Title of Invention	LUBRICATION STRUCTURE IN ENGINE
Abstract	[Problem] To achieve improvement in lubrication performance in a engine by optimizing the structure for recovering scooped oil for enhanced oil recovery efficiency. [Solving means] The oil which has been scooped up by means of the rotation of a clutch 2b is captured by capturing means. The capturing means is formed as a groove-shaped concave 13d provided to a ring-shaped inner surface 13c of a case cover facing an circumference 2b1 of a clutch. The captured oil is smoothly guided to a recovered oil receiver llA of a crankcase 10 via a bent-upper edge part l5i of an oil guide plate 15. The recovered oil passes through dropping holes 10C1 of a recovered oil path 10C and is supplied to a gear engagement part of a transmission system located below the path lOCo [Selected drawing] Figure 3

Title of Invention

LUBRICATION STRUCTURE IN ENGINE

Abstract

[Problem] To achieve improvement in lubrication performance in a engine by optimizing the structure for recovering scooped oil for enhanced oil recovery efficiency. [Solving means] The oil which has been scooped up by means of the rotation of a clutch 2b is captured by capturing means. The capturing means is formed as a groove-shaped concave 13d provided to a ring-shaped inner surface 13c of a case cover facing an circumference 2b1 of a clutch. The captured oil is smoothly guided to a recovered oil receiver llA of a crankcase 10 via a bent-upper edge part l5i of an oil guide plate 15. The recovered oil passes through dropping holes 10C1 of a recovered oil path 10C and is supplied to a gear engagement part of a transmission system located below the path lOCo [Selected drawing] Figure 3

Full Text	[Name of document] Specification [Title of the invention] LUBRICATION STRUCTURE IN ENGINE [Technical field] [0001] The present invention relates to a lubrication structure in an engine, more particularly relates to an improvement technology for an oiling system in which lubrication is performed by scooping up oil accumulated in the lower part of a crankcase. [0002] [Background art] As a lubrication structure in an engine, there have heretofore been known a lubrication structure in an engine in which oil accumulated in the lower part of a crankcase is scooped up by means of the rotation of a clutch equipped with a mainshaf t (a driveshaft for a transmission) which rotates in conjunction with a crankshaft, then the scooped oil is received by oil receivers provided on the inner walls of the crankcase and a clutch cover, the received oil which has been received by these oil receivers is then supplied via a path to an oil room extending above a transmission system, the oil supplied to the oil room drops onto a gear engagement part of the transmission system on the mainshaft and a countershaft (a power take-off shaft) via dropping holes formed in the oil room, and thereby the gear engagement parts is lubricated. (See Patent document 1, for example) [Patent document 1] Japanese Utility Model Publication No. Hei05-33686 (pages 2 to 3, Figs 1 to 3) [Disclosure of the invention] [Problems to be solved by the invention] [0003] The engine described in the Patent document 1 is configured in such a way that a crankshaft is movably supported in a crankcase, that the rotation of the crankshaft is transmitted to a mainshaft (a driveshaft for a transmission) via engagement of gears and a clutch, and that the rotation of the mainshaft is further transmitted to a power take-off shaft (a countershaft) via a transmission system. [4] A lubrication structure is provided in which oil accumulated in the bottom (lower part) of the crankcase is scooped up by means of the rotation of the above-described clutch equipped on the mainshaft and in which the scooped oil is used to lubricate gear engagement parts of the transmission systems on the mainshaft and the countershaft. [5] More specifically, concerning the lubrication for the gear engagement part in the transmission system, oil which has been scooped up by the above-described clutch is received by oil receivers provided on the inner walls of the crankcase and a clutch cover and the oil is supplied to an oil room via a path. [6] A part of the oil which has been supplied to the oil room is configured to be dropped from the oil room onto the gear engagement parts of the transmission systems on the mainshaft and the countershaft via a falling hole. In addition, the other part of the scooped oil is configured to be supplied to the countershaft via a communicating path. [7] Incidentally, the oil receiver in the lubrication structure described in the Patent document 1, which receives oil scooped up by means of the rotation of the clutch, is directly formed on the inner walls of the crankcase and crutch cover in the form of a concave or a groove and is integrally formed with the case and cover. Accordingly, selection of a structure or shape, which has a sufficient oil recovery function as an oil receiver, is restricted. Thus, it is required to enhance efficiency in the recovery of the scooped oil in such an oil receiving structure where the oil receiver is formed integrally with a case and cover. [8] In consideration of the above-described problems, it has been required to provide an improvement technology for a lubrication structure in an engine, in which oil accumulated in the bottom (lower part) of a crankcase is scooped up by means of a rotator rotating in the crankcase and the scooped oil is used to lubricate a gear engagement part and the like in the crankcase. Here, the improvement technology is one which enhances the lubrication efficiency in the gear engagement part and the like by enhancing the efficiency of recovering the scooped oil, and which can be provided at low price with simple structure modification. [Means for solving the problems] [9] The present invention is an improvement in a lubrication structure in an engine, which is provided to solve the foregoing problems. The present invention is a lubrication structure in an engine, which includes: a crankcase having an oil pan at its lower position; a crankshaft which is rotatively supported in the crankcase; a rotating member which rotates in conjunction with the crankshaft and which scoops up oil in the oil pan located at the lower position of the crankcase; an oil receiver for receiving oil which has been scooped up by means of the rotating member; and an oil path for circulating oil in the crankcase for lubrication, the oil having been received by the oil receiver. Here, the oil receiver has an oil guide plate for guiding oil to the oil receiver, the oil having been scooped up by the rotating member. [10] Moreover, the oil guide plate is characterized in that it is capable of guiding the scooped oil to the oil receiver by allowing the oil guide plate to abut the oil receiver, and that the oil receiver is positioned above a gear engagement part of a transmission system. Furthermore, the oil guide plate is characterized in that it has at its upper portion a bent-upper edge part for guiding the scooped oil to the oil receiver, the bent-upper edge part being tilted and the upper edge thereof bent in a direction away from the oil receiver. [0011] The oil guide plate is characterized in that a roof plate for covering the guide plate in the side view thereof is arranged thereto, and the roof plate is characterized in that it has a structure for capturing oil which has been scooped up by the rotating member and for guiding the captured oil to the oil receiver. Moreover, the roof plate is characterized in that it is tilted in a way that oil is guided to the oil receiver by moving on the surface thereof. [Effects of the invention] [0012] In the present invention as set forth in claim 1, the oil receiver has, in the lubrication structure in an engine, an oil guide plate for guiding oil which has been scooped up by the rotating member to the oil receiver. Accordingly, it is possible to effectively guide oil which has spattered in multiple directions to the oil receiver by means of the oil guide plate and to improve oil recovery efficiency. As a result, it is made possible to improve lubrication performance in an engine. [0013] In the present invention as set forth in claim 2, the oil guide plate is capable of guiding the scooped oil to the oil receiver by allowing the oil guide plate to abut the oil receiver and the oil receiver is positioned above the gear engagement part of the transmission system, in the invention set forth in claim 1. Accordingly, it is possible to effectively guide oil which has spattered in multiple directions to the oil receiver by means of the oil guide plate and to improve oil recovery efficiency. In addition, since the oil receiver is positioned above the gear engagement part, oil drops by gravity and thereby the gear engagement part can be lubricated effectively. As a result, it is made possible to improve lubrication performance in an engine. In the present invention as set forth in claim 3, the oil guide plate has at its upper portion a bent-upper edge part for guiding the scooped oil to the oil receiver, the bent-upper edge part being tilted and the upper edge thereof bent in a direction away from the oil receiver, in the invention set forth in one of claims 1 and 2. Accordingly, it is made possible to smoothly guide the scooped oil by means of the bent-upper edge part and to highly effectively guide the oil to the oil receiver. [15] In the present invention as set forth in claim 4, a roof plate for covering the guide plate in the side view thereof is arranged to the oil guide plate, and the roof plate has a structure for capturing oil which has been scooped up by the rotating member and for guiding the captured oil to the oil receiver in the invention set forth in any one of claims 1 to 3. Accordingly, the oil which has been scooped up by the rotating member and has been captured by the roof plate is efficiently guided to the oil receiver via the oil guide plate and is recovered. [16] In the present invention as set forth in claim 5, the roof plate is tilted in a way that oil is guided to the oil receiver by moving on the surface thereof, in the invention set forth in clam 4. Accordingly, the oil which has been scooped up by the rotating member moves on the surface of the roof plate and thereby the oil is efficiently guided to the oil receiver. [Best modes for carrying out the invention] [0017] The oil accumulated in the lower part of a crankcase is scooped up by use of a rotator attached to a shaft of a transmission system, the shaft being rotated by a crankshaft. The oil which has been scooped up by the rotator is collected by use of a roof plate, and the collected oil is guided to an oil receiver by use of an oil guide plate. In this way, the present invention is carried out. [Embodiment] [0018] An embodiment of the present invention will be described on the basis of Figs. 1 and 10. Pig. 1 shows a side view of a motorcycle which is a vehicle A to be mounted with an engine E where improvement in the lubrication of the present invention is to be applied. The motorcycle of the present invention includes a head pipe A1 as a frame member for the front thereof. A front fork A2 is attached below the head pipe A1. A front wheel A3 is rotatively supported by the front fork A2 . Above the head pipe A1, a handle bar A4 is attached. In addition, a mainframe A5 is connected to the head pipe Al, obliquely pointing downward and extending in a rear direction therefrom. At the rear upper portion of the mainframe A5, a seat rail A6 which extends in a rear direction and points in a substantially horizontal direction therefrom is attached. Moreover, at the rear end portion of the mainframe A5 which bends downward, a back stay A7 extending in a rear direction and pointing upward therefrom is attached. The rear end portion of the back stay A7 is connected to the rear side of the seat rail A6. [20] The front end portion of a swing arm A8 is pivotally supported in the vicinity of the attached portion of the back stay A7 to the mainframe A5 . A rear wheel A9, which is a driving wheel of the vehicle A, is supported at the rear side of the swing arm A8 . Further, a seat member A10 for a rider is attached on the seat rail A6 located in a rearward position of the mainframe A5. [0021] Furthermore, the top end of a down tube All is connected to the head pipe Al. The downtube All points and extends in a downward direction and then extends substantially in a horizontal direction. The end portion thereof is connected to the bent end portion of the mainframe A5. The engine E is arranged in a space surrounded by the mainframe A5 and the downtube All, so that the engine E is held in the space. The space is formed below the mainframe A5. The engine E is supported by the mainframe A5 and the downtube All via supporting members. In this way, the engine E is mounted on the vehicle A which is an motorcycle. [0022] Fig. 1 shows the engine E in a state of being mounted on the vehicle A. Fig. 1 also shows an inlet pipe El arranged on the rear upper portion of the engine E, an air cleaner Ell connected thereto, an exhaust pipe E2 which is arranged on the front side of the engine E and is passing the side of the engine E to extend in a rear direction, a muffler E21 connected to the rear side of the exhaust pipe E2, and the like. In addition, Fig. 1 shows a radiator E3 for cooling the engine E, which is arranged in the front side of the engine E, a blowby gas pipe E4, a kick starter pedal E5 and the like. [23] A structure outline of the engine E to be mounted on the above-described motorcycle will be described. [24] In Fig. 2, the principal portion of the engine E of the present invention is shown in cross-sectional view. As shown in this figure, the engine E includes a crankcase 10, a cylinder block 20 connected to the crankcase 10, a cylinder head 30 to be connected to the cylinder block 20 and a cylinder head cover 40 . These are clamped and fixed together by means of stud bolts and the like, thereby constituting the main structure of the engine E. [25] The crankcase 10 has a structure in which half cases 11 and 12are integrally connected to each other. The half cases 11 and 12 are formed by being divided in right and left. In the crankcase 10 in which these half cases 11 and 12 are combined, a crankshaft 1, a mainshaft 2 and countershaft 3 of a transmission system 6, which are extending in parallel with the crankshaft 1, and the like are rotatively bearing-supported. [0026] The crankshaft 1 is supported by bearings la and lb and, to a crankpin lc thereof, a connecting rod Id is roratively attached via a bearing located at the large-end le thereof. A piston P is swingably attached to the small-end If of the connecting rod Id via a piston pin lg. In this embodiment, there is provided one piston P and the engine E of the present invention is a 4-cycle single cylinder engine. [27] A gear lh having relatively a small outer diameter is attached near the right end of the crankshaft 1. The gear lh is a drive gear lh to be engaged with a driven gear 2a. The driven gear 2a is one to be loosely fitted to the mainshaft 2 of the above-described transmission system 6. The driven gear 2a, which is loosely fitted to the mainshaft 2, is provided near the right end of the mainshaft 2 together with a clutch 2b. The clutch 2b is one which selectively transmits the rotation of the driven gear 2a to the mainshaft 2 by means of its open/close operation. In addition, the shaft part located between bearings 2c and 2d which rotatively support the mainshaft 2 is equipped with a plurality of gears 2e for shifting. [28] The countershaft 3 is equipped with a plurality of gears 3a, which selectively engages with the plurality of gears 2e equipped to the mainshaft 2 to rotate the countershaft 3 at a desired gear ratio. These gears 3a are equipped to the shaft part located between bearings 3b and 3c supporting the countershaft 3. Moreover, a sprocket 3d for driving the rear wheel A9 which is a driving wheel of the vehicle A is attached to the left end of the countershaft 3. [0029] Accordingly, the rotation of the crankshaft 1 is transmitted to the mainshaft 2 via engagement between the drive gear lh and the driven gear 2a and further via the open/close clutch 2b. The rotation of the crankshaft 1, which has been transmitted to the mainshaft 2 is then transmitted to the countershaft 3 from the mainshaft 2 via appropriate and selective engagement between the plurality of gears 2e and 3a for shifting, which are equipped on the countershaft 3 and mainshaft 2. [30] The rotation transmitted from the mainshaft 2 to the countershaft 3, which is conducted via selective engagement of gears 2e and 3a, is used to rotate the countershaft 3 at a desired gear ratio. The gear ratio is based on the selection of the gears 2e and 3a to be engaged. The rotation of the countershaft 3 is transmitted to the driving sprocket 3d attached to the left end of the shaft 3, and is further transmitted to the rear wheel A9 which is a driving wheel for driving a vehicle (see Fig. 1) via an unillustrated driving chain or the like, thereby making it possible to allow the vehicle A to drive at a desired speed. [31] A cylinder hole 20a for the piston P is provided in the cylinder block 20. The engine E of this embodiment includes one piston P, and accordingly only one cylinder hole 20a is provided therein. As is well known, the piston P reciprocates in the cylinder hole 20a in conjunction with the motion of the connecting rod Id, the motion triggered by the rotation of the crankshaft 1. [32] In the cylinder head 30, a combustion chamber 3 0a is provided which is formed by the cylinder hole 20a of the cylinder block 20 and the concave located at the lower part of the cylinder head 30. Unillustrated openings for intake/exhaust are formed in this combustion chamber 30a. These openings respectively communicate with intake and exhaust paths. In addition, intake and exhaust valves 3 0b and 30c for opening/closing the openings, only parts of which are shown here, are disposed in the openings. The cylinder head 30 includes valve mechanism for activating the intake and exhaust valves 30b and 30c and, a cam 30d, a camshaft 30e and the like which constitute the valve mechanism are disposed therein. The camshaft 3 0e is attached with a sprocket 30g for a timing chain 30f. The timing chain 30f is used to rotate the camshaft 30e with half the number of the rotation of the crankshaft 1. The cylinder head cover 40 is equipped to the upper part of the cylinder head 30. [34] The engine E of this embodiment generally includes such a structure that has been described above. However, the engine E further includes a characteristic lubrication structure. Hereinafter, this lubrication structure will be described. [35] As described hereinbefore, and as shown in Fig. 2 and in a diagram of Fig. 5, the crankcase 10 includes a structure in which the right and left divided half cases 11 and 12 are integrally connected to each other. In the crankcase 10, the crankshaft 1 is rotatively bearing-supported. The rotation of the crankshaft 1 is transmitted to the mainshaft 2 of the transmission system G via engagement between the drive gear lh and driven gear 2a and via the clutch 2b. [36] The rotation of the crankshaft 1, which has been transmitted to the mainshaft 2, is configured to be further transmitted to the countershaft 3 via engagement between the gears 2e and 3a for shifting. In the lubrication structure of this embodiment, the oil scooped up by the rotating part of the rotation transmission system is utilized to lubricate the gear engagement part G1 of the transmission system G of the engine E. [37] For the purpose of scooping up oil by means of the rotating part of the rotation transmission system, the clutch 2b on the mainshaft 2, which is a rotator having a maximum diameter in this rotation transmission system, is utilized in this embodiment. Accordingly, the lower part of the clutch 2b is dipped into oil accumulated in the lower part of the crankcase 10. [38] As shown in Figs. 3 and 4 and in the diagram of Fig. 5, there is provided a structure in which the oil, which has been scooped up by means of the rotation of the clutch 2b, is captured by oil capturing means and is recovered in an oil receiver 11A, and in which the recovered oil is supplied from the oil receiver 11A via oil paths 11C and 12C communicating with the oil receiver 11A in order to lubricate the gear engagement part G1 of the transmission system G. The oil paths 11C and 12C are located in the right and left divided half cases 11 and 12 of the divided crankcase 10. [39] In order to lubricate the gear engagement part G1 of the transmission system G, such a structure is adopted that can be understood from Fig. 6 showing the side view of the right half case. In other words, a structure is adopted in which the transmission system G is located below the recovered oil receiver 11A and is positioned immediately underneath an oil path 10C to be described later. The oil path C is one which is composed of the recovered oil paths 11C and 12C, is communicating with the recovered oil receiver 11A, and is crossing the crankcase 10 in the direction orthogonal to the front-back-direction of the vehicle. Here, in the drawing, reference numerals 4, 5 and 6 denote a shift drum, a balancer shaft and an oil pump, respectively. [40] As shown in Fig. 2 and in the diagram of Fig. 5, the clutch 2b is equipped to the right end of the mainshaft 2. While maintaining this state, the most part of the clutch 2b is configured to protrude to the outside from the side 11a of the right half case 11 of the divided crankcase 10, the side 11a being equipped with the clutch. The portion of the clutch 2b, protruding from the side 11a of the right half case 11, is completely covered with the case cover 13. 10041J The outer shape of the case cover 13 has a bowl-shaped concave for covering a portion of the clutch 2b, the portion protruding from the right half case side 11a (see Figs. 2, 3 and 5) . An opening 13a of the cover 13, which substantially forms the opening of the bowl-shaped concave, is applied to the side 11a of the right half case 11 from outside, and is fixed thereto by means of appropriate fixing means such as bolts. In this way, the case cover 13 is attached to the side 11a of the half case 11. Moreover, the outer side of the case cover 13, which substantially forms a bottom 13b of the bowl-shaped concave of the case cover 13, is configured to have a complete sealed structure. The case cover 13 is attached to the side 11a of the right half case 11, and thereby the side 11a of the right half case 11 is completely covered. [42] As can be seen by referring to Figs. 2 to 5, the substantial depth of the concave of the bowl-shaped case cover 13 which covers the protruding portion of the clutch 2b is set. In addition, the ring-shaped inner surface 13c, which covers the circumference 2bl of the outside diameter of the clutch 2b, is substantially concentric with the circumference 2bl of the clutch 2b. The circumference 2bl of the outside diameter of the clutch 2b and the ring-shaped inner surface 13c of the case cover 13 are configured to face each other with a relatively narrow space interposed therebetween. As shown in Figs. 3 to 5, on the ring-shaped inner surface 13c of the upper part of this case cover 13, there is formed a groove-shape concave 13d obliquely crossing the ring-shaped inner surface 13c in the width direction. [43] This groove-shaped concave 13d is the means for capturing the oil which has been scooped up by means of the rotation of the clutch 2b, and is formed on the ring-shaped inner surface 13c corresponding to a predetermined upper portion of the case cover 13 as a groove 13e obliquely crossing the ring-shaped inner surface 13c in the width direction. The groove 13e is a structure which has been cut to have a certain width and depth. The structure of the ring-shaped inner surface 13c, in which the oil capturing means is provided, is positioned as a roof plate 14 which covers above an oil guide plate 15 when viewed from the side of the oil guide plate 15, the roof plate 14 cooperating with the oil guide plate 15 of oil recovering means to be described later (see Fig. 3). The groove-shaped concave 13d which is the oil capturing means in the roof plate 14 is formed at a position where the oil, which has been scooped up by means of the rotation of the clutch 2b, can be most effectively captured. As for the optimal position for capturing the scooped up oil, the ring-shaped inner surface 13c corresponding to a certain upper portion of the case cover 13 is selected, the position located substantially above both the mainshaft 2 and countershaft 3 of the transmission system G when the crankcase 10 is viewed from the top thereof as shown in Fig. 5. [45] As described above, the groove-shaped concave 13d which is the oil capturing means in the roof plate 14 obliquely crosses the ring-shaped inner surface 13c of the case cover 13 in the width direction. More specifically, from the outside of the case cover 13 to the inside of the crankcase 10, that is, from the cover sealing side 13f, which is the right side of the case cover 13, to the cover opening side 13g which is the left side of the case cover 13 as shown in Figs. 3 to 5, the groove-shaped concave 13d obliquely crosses the ring-shaped inner surface 13c of the case cover 13 in the width direction. The groove-shaped concave 13d obliquely crosses the ring-shaped inner surface 13c in the width direction, so that the groove-shaped concave 13d can be brought in line with the rotation direction R of the clutch 2b. [46] The groove-shaped concave 13d, which obliquely crosses the ring-shaped inner surface 13c constituting the roof plate 14 in the above-described manner, is formed to have the following structure, of which the cross-sectional view is shown in Fig. 3B. That is, the structure is one which is formed by gouging the ring-shaped inner surface of the case cover 13 to have an arc-shaped groove with certain width and depth,the groove-shaped concave 13d extending in the crossing direction in a smooth curve. In addition, as can be seen from Fig. 3A, the top of the groove-shaped concave 13d, that is, the bottom 13h of the groove-shaped concave 13d is a structure which has a gentle curve and gets slightly higher from the cover sealing side 13f, which is the outside of the case cover 13, to the cover opening side 13g which is the inner side thereof. Specifically, the groove-shaped concave 13d is formed to have such a structure that has a gentle curve and in which the bottom 13h get deeper from the cover sealing side 13f, which is the outside of the case cover 13, to the cover opening side 13g which is the inside thereof. [47] The above-described structure of the groove-shaped concave 13d is the optimal structure for effectively capturing the oil which has been scooped up by means of the rotation of the clutch 2b. The oil which has been captured by the groove-shaped concave 13d is configured to be guided from the roof plate 14 side of the case cover 13 to the inner side of the crankcase 10 via the oil guide plate 15 to be described later, more specifically, is configured to be guided to the oil recovered oil receiver 11A, which is formed along the side 11a of the right half case 11 (see Figs. 3 to 5). [48] To the side 11a of the right half case 11 of the crankcase 10, there is formed the above-described recovered oil receiver 11A. The oil receiver 11A communicates with the groove-shaped concave 13d for capturing oil, which is formed in the roof plate 14 of the case cover 13 along the side 11a. As shown in Figs. 5 to 8 and the like, this recovered oil receiver 11A is accordingly formed above the mainshaft 2 of the transmission system G, in the position slightly near the rear side of a vehicle. This is the position substantially above the gear engagement part Gl, where the shifting gears 2e and 3a are engaged with each other. The shifting gears 2e and 3a are located on the mainshaft 2 and countershaft 3 of the transmission system G. For reference purposes, reference numeral 7 in Fig. 8 denotes a breather pipe. [49] As shown in Figs. 3 and 6, the oil guide plate 15 is allowed to abut to a side lie of a divided space 11c and the recovered oil receiver 11A is covered therewith, thereby forming the oil guide plate 15 (see Figs. 3 and 6). Here, the side lie is the side 11a of the right half case 11 (see Fig. 3) , specifically, this is the side of the divided space 11c partitioned by a rib lib on the side 11a of the right half case 11 to which the clutch 2b is equipped (see Fig. 6) , more specifically, this is the side of the lower part lid of the divided space 11c partitioned by the rib lib, the position corresponding to the position substantially above the mainshaft 2 on the side 11a. This oil receiver 11A is placed at a position llf, which is near the rear side of a vehicle and is lower than the lower part lid of the divided space 11c covered with the oil guide plate 15. [50] In addition, the side lie of the lower part lid of the divided space 11c (see Fig. 3) is covered with the oil guide plate 15 . At the same time, the lower part 11 j of a small divided space Hi is covered with the oil guide plate 15. The small divided space lli is adjacent to the divided space 11c partitioned by the rib lib with a rib llg interposed therebetween and is partitioned by a rib llh. In this way, an oil receiver 11B is formed which is different from the recovered oil receiver 11A (see Fig. 6). [51] The oil receiver 11B is positioned above the mainshaft 2, which is slightly near the front side of a vehicle, and is formed at a position Ilk which is lower than the lower position llj of the small divided space Hi. This one-step lower position Ilk of the small divided space is situated at a position further slightly lower than the lower position llf of the recovered oil receiver 11A. The oil receiver 11B is one provided for the injected oil and therefore is provided with an oil inlet 11m communicating therewith, which is shown in Fig. 9. [52] As shown in Figs. 10A and 10B, the oil guide plate 15 is a plate-like member formed of a relatively thin steel plate or the like. As described above, the plate 15 is allowed to abut the side 11a of the right half case 11 and is fixed thereto in such a way that the lower parts lid and llj of the divided spaces 11c and lli on the side 11a of the right half case 11 of the crankcase 10 are covered with the plate 15. The lower parts lid and llj are partitioned by the ribs lib, llg and llh (see also Figs. 3 and 5 and the like). The oil guide plate 15 is attached via the following two points by means of bolts B: that is, an upper position 15a of the plate 15, which corresponds to the position above the mainshaft 2 and is slightly rear side of the plate 15 when the plate 15 is in the contact state; and a position 15b of the plate 15, which is lower and the forefront position and is also in the vicinity of the oil receiver 11B for the injected oil (see also Fig. 6) . [54] The oil guide plate 15 covers the lower parts lid and llj of the divided spaces 11c and lli which are partitioned by the ribs lib, llg and llh on the right half case of the crankcase 10. Accordingly, when the oil guide plate 15 is viewed from the side, the outer shape thereof has a structure in which its lower shape 15A is brought in line with the ribs lib and llh substantially forming the lower parts lid and llj of the divided spaces 11c and lli. The outer shape of the oil guide plate 15 is also configured to include a center part 15c in the upper side thereof, which extends in the form of a substantially convex arc, and end parts 15d and 15e. The end parts 15d and 15e of the plate 15 further extend downward in the front- back-directions of a vehicle. Here, the center part 15c having a substantially convex arc is sandwiched by the end parts 15d and 15e. [55] Moreover, an upper shape 15B is configured to include the following structure: that is, a part of the plate 15, which is near the rear side of a vehicle, is a linear part 15f obliquely descending in the rear direction; a linear part 15g horizontally extending in the front-back-direction of the vehicle A is connected to this linear part 15f; and furthermore, a curve part 15h of the plate 15, which is near the front side of a vehicle and extending in the form of a segment of a circle, is connected to this linear part 15g. Accordingly, on the whole, the plate 15 has the shape that is similar to a sector when the plate 15 is viewed from the side. The linear part 15f of the upper shape 15B of the plate 15, which is near the rear side of a vehicle and is obliquely descending in the rear direction, is a bent- upper edge part 151 in which the upper edge thereof is bent in the direction away from the crankcase 10 (see also Fig. 10B). [56] In the state of installing the oil guide plate 15 on the side 11a of the right half case 11, by which the divided spaces 11c and 111 are covered, the lower spaces llf and Ilk of the divided spaces 11c and 111 are considered to be portions corresponding to the above-described two oil receivers 11A and 11B. Here, the lower spaces llf and Ilk are covered with the end parts 15d and 15e which further extend downward and in which the center part 15c having a convex arc is interposed therebetween. [57] In other words, the lower space llf of the divided space 11c is considered to be the recovered oil receiver 11A, the lower space llf being covered with the part 15d of the oil guide plate 15. The part 15d is located in the rear side and further extends downward when viewed from the front-back-direction of the vehicle A. Moreover, the lower space Ilk of the divided space lli is formed as the oil receiver 11B for the injected oil, the lower space lli being covered with the part 15e of the oil guide plate 15. The part 15e is located in the front side and further extends downward. [58] The bent-upper edge part 15i of the upper shape 15B of the oil guide plate 15 is positioned above the recovered oil receiver 11A. The bent-upper edge part 15i makes it easy to guide the oil flowing from the oil capturing groove-shaped concave 13d of the roof plate 14 to the recovered oil receiver 11A. This is achieved because the bent-upper edge part 15i has a bent structure bending in the direction away from the crankcase 10 and a linear structure 15f obliquely descending in the rear direction of the bent-upper edge part 15i. With this configuration, it is made possible to effectively guide the scooped oil to the recovered oil receiver 11A. [59] In addition, the curve part 15h of the oil guide plate 15, which points to the front side of the vehicle A and extends downward in the form of a segment of a circle, is positioned just above the oil receiver 11B for the injected oil. [60] The recovered oil receiver 11A is communicated with the oil path 11C which extends in the direction orthogonal to the front-back-direction of the vehicle A and which crosses in the right half case 11 of the crankcase 10, specifically, as shown in the diagrams of Figs. 5 and 6, is communicated with the oil path 11C which allows the recovered oil to flow therein and extends in such a manner that it crosses in the half case 11 just above the gear engagement part G1 of the shifting gears on the mainshaft 2 and countershaft 3 of the transmission system G while maintaining parallel relation with both the shafts 2 and 3. Moreover, an oil path 10D2 serving to circulate and supply the injected oil also communicates with this recovered oil receiver 11A, which will be described later. [0061] The recovery oil path 11C which crosses in the right half case 11 is communicated with and connected to the oil path 12C similarly extending and crossing in the left half case 12 of the crankcase 10, resulting one oil path 10C in which these paths are communicated with and connected to each other to substantially form single-piece structure. As a result, the oil path 10C crossing in the crankcase 10 has the following structure: that is, the oil path 10C extends above the gear engagement part G1 and has a length that is enough to hold the entire length of the gear engagement part G1 of the shifting gears on the mainshaft 2 and countershaft 3 of the transmission system G. In this way, the recovery oil path 10C is formed which crosses in the crankcase 10 consisting of the right and left divided half cases 11 and 12. [0062] As described above, the recovery oil path 10C, crossing in the crankcase 10, passes above the gear engagement part G1 of the transmission system G. In this oil path 10C, there is formed oil dropping means for dropping and supplying the recovered oil running through the oil path to the gear engagement part Gl. In this embodiment, there are formed dropping holes 10C1 through which oil is dropped (see Figs. 3 and 5). The dropping hole 10C1 has a predetermined diameter, and the plurality of dropping holes 10C1 is appropriately formed and opened along the path 10C at a predetermined intervals in the front-back-direction. However, the size and shape of the dropping hole 10C1, furthermore, the number of the dropping hole 10C1 and the intervals between the dropping holes 10C1 and the like are set as appropriate. [0063] Moreover, as can be seen from the diagram of Fig. 5, the injected oil receiver 11B is communicated with an oil path 11D through which the injected oil flows, as similar to the recovered oil receiver 11A. Here, the oil path 11D extends in the direction orthogonal to the front-back-direction of the vehicle A and crosses in the right half case 11 of the crankcase 10. As described above, and as apparent from the references of Fig. 6 and the like, the injected oil receiver 11B is located at a position that is slightly lower than the recovered oil receiver 11A. Accordingly, the injected oil path 11D is also located at a position that is slightly lower than the recovered oil path 11C, and is extending and crossing in the half case 11. Although not shown in Fig. 5, this oil receiver 11B is communicated with the oil inlet 11m (see Fig. 9) through which oil is injected as described above. The oil path 11D crossing in the divided right half case 11 is communicated with and connected to an oil path 12D which likewise extends and crosses in the left half case 12 of the crankcase 10, resulting one oil path 10D in which these paths are communicated with and connected to each other to substantially form single-piece structure. The oil path 10D forms the injected oil path 10D which crosses in the crankcase 10 consisting of the right and left divided half cases 11 and 12. A part of the injected oil flowing through the injected 11 path 10D is supplied to the mainshaft 2 via a path. A part of the path is not illustrated here. The other part of the oil is circulated and supplied to the recovered oil receiver 11A via a connection path 12D1 and a second injected oil path 12D2, which are described later. [65] As can be seen from the above statements, the two paths cross in the crankcase 10 consisting of the right and left divided half cases 11 and 12. That is, the recovered oil path 10C and the injected oil path 10D are in parallel with each other and crossing in the crankcase 10 while maintaining a predetermined interval therebetween. As shown in Fig. 5, in the crankcase 10, there is formed an oil path 10D2 crossing in the crankcase 10. The oil path 10D2 is different from the recovered oil path 10C and the injected oil path 10D. [0066] One end of this oil path 10D2 is communicated with the connection path 12D1 which is formed inside the left side wall of the left half case 12 shown in the drawing and which is connected to the above-described injected oil path 10D crossing in the crankcase 10. The other end of the oil path 10D2 is communicated with the recovered oil receiver 11A of the right half case 11. The oil which has been injected into the injected oil receiver 11B via this oil path 10D2 is configured to be circulated and supplied to the recovered oil receiver 11A. This oil path forms the second oil path 10D2. [67] An overflow hole X for ejecting excess oil is provided to the side of the right half case 11, the side corresponding to a slightly lower part of the gear engagement part Gl in the transmission system G of the mainshaft 2 and countershaft 3, more specifically, the side corresponding to a slightly lower part of the gear engagement part Gl that is located substantially beneath the recovered oil receiver 11A when the half case 11 is viewed from the side. In this embodiment, the overflow hole X is only provided in the right half case 11 shown in Figs. 6 to 8. However, a similar overflow hole can also be provided in the left half case 12. [68] Here, on the basis of Figs. 3 to 5, brief descriptions will be added for explaining the recovery of the oil which has been scooped up by the clutch 2b and for explaining the effect of lubrication using this oil. [69] It is to be noted that the rotating member, the oil path, the oil guide plate and the roof plate, which are described in the claims, are equivalent to the clutch 2b, the oil path 11C, the oil guide plate 15 and the roof plate 14, respectively. [70] H103-3630 The oil which has been scooped up by means of the rotation R of the clutch 2b attached to the mainshaft 2 is captured by the roof plate 14 of the case cover 13, that is, by the structure provided with the groove-shaped concave 13d formed on the predetermined upper portion of the ring-shaped inner surface 13c of the case cover 13. The scooped oil flows in such a way that it obliquely crosses the ring-shaped inner surface 13c along the groove-shaped concave 13d. [71] The captured oil that flows along the groove-shaped concave 13d is effectively guided by the structure of the groove 13e, which extends in a smooth curve and in which its bottom 13h gradually deepens from outside to the crankcase 10 side. The oil is then allowed to flow toward a crankcase 10 side open-end of the groove-shaped concave 13d, which is formed at an upper portion of the oil guide plate 15. The oil which has reached the crankcase 10 side-open-end of the groove-shaped concave 13d is guided by the bent part of the bent-upper edge part 15i, which bends in the direction away from the crankcase 10 located behind (left) the oil guide plate 15. This oil then flows along an inclined plane 15 pointing to the rear side of the bent-upper edge part 15i, and then is guided to the recovered oil receiver 11A from the side 11a of the right half case 11. [73] The recovered oil which has been guided to the recovered oil receiver 11A flows along the recovered oil path 11C of the right half case 11, and flows toward the recovered oil path 12C of the left half case 12 . In this flowing process, the oil drops by gravity from the plurality of oil dropping holes 10C1 formed in the recovered oil paths 11C and 12C to the gear engagement part Gl of the mainshaft 2 and countershaft 3 of the transmission system G located below the paths 11C and 12C, thus the lubrication of the gear engagement part Gl is achieved. Furthermore, this embodiment adopts such a configuration that allows the recovered oil to flow by means of the plurality of oil dropping holes 10C1. However, a configuration maybe adopted in which such dropping holes are not provided in the recovered oil paths 11C and 12C and the oil overflowed in the recovered oil paths 11C and 12C begins to come out from their edges. [74] Meanwhile, the oil which has been injected from the oil inlet 11m (see Fig. 9) floods into the injected oil receiver 11B, flows from the injected oil receiver 11B along the injected oil path 11D of the right-side half case 11, flows through the injected oil path 12D of the left half case 12, and crosses crankcase 10 consisting of the right and left divided half cases 11 and 12. A part of this oil is then supplied to the mainshaft 2 from an opening 12E (see Fig. 2) via an unillustrated path communicating with the injected oil path 12D. [75] The other part of the oil flows from the injected oil path 12D into the connection path 12D1 which is located inside the left side wall of the left half case 12 shown in Fig. 5 . However, since the injected oil receiver 11B and injected oil paths 11D and 12D are located at positions that are slightly lower than the recovered oil receiver 11A and the recovered oil paths 11C and 11D, only the injected oil in which the liquid level is in excess of certain limits is allowed to flow into the connection path 12D1. [76] The oil flowed into the connection path 12D1 makes U-turn after passing through the connection path 12D1. This oil again flows through the second injected oil path 10D2 crossing the crankcase 10, is circulated and supplied to the recovered oil receiver 11A of the right half case 11, meets the aforementioned recovered oil in this recovered oil receiver 11A, follows the above-described path of the recovered oil, and is supplied to the gear engagement part G1 of the transmission system G for the aforementioned lubrication. In the embodiment of the present invention, the groove-shaped concave 13d of the roof plate 14 crosses in the oblique direction while facing the circumference 2bl and pointing to the rotation direction of the clutch 2b, and has a structure that deepens gradually from outside to inside with a gentle slope. Accordingly, it is possible to effectively capture the oil which has been scooped up by means of the rotation of the clutch 2b and to facilitate the smooth guidance of the captured oil. [78] The oil guide plate 15 includes the bent-upper edge part 15i which points to the lower adjacent part of the groove - shaped concave 13d of the roof plate 14 in the oblique and backward direction and which is bent in the direction away from the crankcase 10 side. Accordingly, the flowing oil which has been guided by the groove-shaped concave 13d of the roof plate 14 is further smoothly guided by the bent-upper edge part 15i and runs down along the bent-upper edge part 15i . In this way, this oil is effectively guided to the recovered oil receiver 11A. [79] The recovered oil receiver 11A is communicated with the recovered oil path 10C crossing the crankcase 10. The plurality of oil dropping holes 10C1 is formed and opened in the path 10C. Oil drops from these holes by gravity and thereby the gear engagement part Gl is lubricated. Accordingly, simple and reliable lubrication of the gear engagement part Gl can be achieved without any extra cost. [80] The oil in the injected oil path 10D is guided to the recovered oil receiver 11A via the connection path 12D1 and the second injected oil path 10D2. Accordingly, oil shortage in the recovered oil path 10C crossing the crankcase 10 is resolved, leading to effective and reliable lubrication of the gear engagement part Gl. [Industrial applicability] In the embodiment of the present invention, the engine having the lubrication structure of the present invention is considered to be an engine for motorcycles . However, the engine having this lubrication structure is not limited to an engine for motorcycles, and accordingly can be used in other similar vehicles. [Brief description of the drawings] [0082] [Fig. 1] Fig. 1 is a side view showing the whole of a vehicle mounted with a engine having a lubrication structure of the present invention. [Fig. 2] Fig. 2 is a cross-sectional view showing the principle structure of the engine of the present invention. [Fig. 3A] Fig. 3A is a side view showing the principle structure of the present invention. [Fig. 3B] Fig. 3B is a cross-sectional view taken along A-A line in Fig. 3A. [Fig. 4] Fig. 4 is a cross-sectional view taken along B-B line in Fig. 3, which shows the principle structure of the present invention. [Fig. 5] Fig. 5 is an explanatory diagram showing the principle structure of the present invention. [Fig. 6] Fig. 6 is a side view showing a right half case of a crankcase of the present invention. [Fig. 7] Fig. 7 is a side view showing the right half case of the crankcase of the present invention, which is similar to Fig. 6. [Fig. 8] Fig. 8 is a view showing another side of the right half case of the crankcase of the present invention. [Fig. 9] Fig. 9 is a view showing the outside of the right half case of the crankcase of the present invention. [Fig. 10A] Fig. 10A is a side view showing an oil guide plate of the present invention. [Fig. 10B] Fig. 10B is a cross-sectional view taken along C-C line in Fig. 10A. [Explanation of reference numerals] [0083] 1...crankshaft 2b....clutch 10...crankcase 11A...recovered oil receiver 11C, 12C... recovered oil path 14...roof plate 15...oil guide plate 15i...bent-upper edge part [Name of document] Claims [Claim 1] A lubrication structure in an engine, which includes: a crankcase having an oil pan at its lower position; a crankshaft which is rotatively supported in the crankcase; a rotating member which rotates in conjunction with the crankshaft and which scoops up oil in the oil pan located at the lower position of the crankcase; an oil receiver for receiving oil which has been scooped up by means of the rotating member; and an oil path for circulating oil in the crankcase for lubrication, the oil having been received by the oil receiver, wherein the oil receiver has an oil guide plate for guiding oil to the oil receiver, the oil having been scooped up by the rotating member. [Claim 2] The lubrication structure in an engine according to claim 1, wherein the oil guide plate is capable of guiding the scooped oil to the oil receiver by allowing the oil guide plate to abut the oil receiver, and the oil receiver is positioned above a gear engagement part of a transmission system. [Claim 3] The lubrication structure in an engine according to one of claims 1 and 2, wherein the oil guide plate has at its upper portion a bent-upper edge part for guiding the scooped oil to the oil receiver, the bent-upper edge part being tilted and the upper edge thereof bent in a direction away from the oil receiver. [Claim 4] The lubrication structure in an engine according to any one of claims 1 to 3, wherein, to the oil guide plate, there is arranged a roof plate for covering the guide plate in the side view thereof, and the roof plate has a structure for capturing oil which has been scooped up by the rotating member and for guiding the captured oil to the oil receiver. [Claim 5] The lubrication structure in an engine according to claim 4, wherein the roof plate is tilted in a way that oil is guided to the oil receiver by moving on the surface thereof.

Full Text

[Name of document] Specification
[Title of the invention] LUBRICATION STRUCTURE IN ENGINE
[Technical field]
[0001]
The present invention relates to a lubrication structure in an engine, more particularly relates to an improvement technology for an oiling system in which lubrication is performed by scooping up oil accumulated in the lower part of a crankcase. [0002]
[Background art]
As a lubrication structure in an engine, there have heretofore been known a lubrication structure in an engine in which oil accumulated in the lower part of a crankcase is scooped up by means of the rotation of a clutch equipped with a mainshaf t (a driveshaft for a transmission) which rotates in conjunction with a crankshaft, then the scooped oil is received by oil receivers provided on the inner walls of the crankcase and a clutch cover, the received oil which has been received by these oil receivers is then supplied via a path to an oil room extending above a transmission system, the oil supplied to the oil room drops onto a gear engagement part of the transmission system on the mainshaft and a countershaft (a power take-off shaft) via dropping holes formed in the oil room, and thereby the gear engagement parts is lubricated. (See Patent document 1, for example)
[Patent document 1] Japanese Utility Model Publication No. Hei05-33686 (pages 2 to 3, Figs 1 to 3) [Disclosure of the invention] [Problems to be solved by the invention] [0003]
The engine described in the Patent document 1 is configured in such a way that a crankshaft is movably supported in a crankcase, that the rotation of the crankshaft is transmitted to a mainshaft (a driveshaft for a transmission) via engagement of gears and a clutch, and that the rotation of the mainshaft is further transmitted to a power take-off shaft (a countershaft) via a transmission system.
[4]
A lubrication structure is provided in which oil accumulated in the bottom (lower part) of the crankcase is scooped up by means of the rotation of the above-described clutch equipped on the mainshaft and in which the scooped oil is used to lubricate gear engagement parts of the transmission systems on the mainshaft and the countershaft.
[5]
More specifically, concerning the lubrication for the gear engagement part in the transmission system, oil which has been scooped up by the above-described clutch is received by oil receivers provided on the inner walls of the crankcase and a clutch cover and the oil is supplied to an oil room via a path.
[6]
A part of the oil which has been supplied to the oil room is configured to be dropped from the oil room onto the gear engagement parts of the transmission systems on the mainshaft and the countershaft via a falling hole. In addition, the other part of the scooped oil is configured to be supplied to the countershaft via a communicating path.
[7]
Incidentally, the oil receiver in the lubrication structure described in the Patent document 1, which receives oil scooped up by means of the rotation of the clutch, is directly formed on the inner walls of the crankcase and crutch cover in the form of a concave or a groove and is integrally formed with the case and cover. Accordingly, selection of a structure or shape, which has a sufficient oil recovery function as an oil receiver, is restricted. Thus, it is required to enhance efficiency in the recovery of the scooped oil in such an oil receiving structure where the oil receiver is formed integrally with a case and cover.
[8]
In consideration of the above-described problems, it has been required to provide an improvement technology for a lubrication structure in an engine, in which oil accumulated in the bottom (lower part) of a crankcase is scooped up by means of a rotator rotating in the crankcase and the scooped oil is used to lubricate a gear engagement part and the like in the crankcase. Here, the improvement technology is one which enhances the lubrication efficiency in the gear engagement part and the like by enhancing the efficiency of recovering the scooped oil, and which can be provided at low price with simple structure modification. [Means for solving the problems]
[9]
The present invention is an improvement in a lubrication structure in an engine, which is provided to solve the foregoing problems. The present invention is a lubrication structure in an engine, which includes: a crankcase having an oil pan at its lower position; a crankshaft which is rotatively supported in the crankcase; a rotating member which rotates in conjunction with the crankshaft and which scoops up oil in the oil pan located at the lower position of the crankcase; an oil receiver for receiving oil which has been scooped up by means of the rotating member; and an oil path for circulating oil in the crankcase for lubrication, the oil having been received by the oil receiver. Here, the oil receiver has an oil guide plate for guiding oil to the oil receiver, the oil having been scooped up by the rotating member.
[10]
Moreover, the oil guide plate is characterized in that it is capable of guiding the scooped oil to the oil receiver by allowing the oil guide plate to abut the oil receiver, and that the oil receiver is positioned above a gear engagement part of a transmission system.
Furthermore, the oil guide plate is characterized in that it has at its upper portion a bent-upper edge part for guiding the scooped oil to the oil receiver, the bent-upper edge part being tilted and the upper edge thereof bent in a direction away
from the oil receiver. [0011]
The oil guide plate is characterized in that a roof plate for covering the guide plate in the side view thereof is arranged thereto, and the roof plate is characterized in that it has a structure for capturing oil which has been scooped up by the rotating member and for guiding the captured oil to the oil receiver.
Moreover, the roof plate is characterized in that it is tilted in a way that oil is guided to the oil receiver by moving on the surface thereof. [Effects of the invention] [0012]
In the present invention as set forth in claim 1, the oil receiver has, in the lubrication structure in an engine, an oil guide plate for guiding oil which has been scooped up by the rotating member to the oil receiver. Accordingly, it is possible to effectively guide oil which has spattered in multiple directions to the oil receiver by means of the oil guide plate and to improve oil recovery efficiency. As a result, it is made possible to improve lubrication performance in an engine. [0013]
In the present invention as set forth in claim 2, the oil guide plate is capable of guiding the scooped oil to the oil receiver by allowing the oil guide plate to abut the oil receiver and the oil receiver is positioned above the gear engagement part of the transmission system, in the invention set forth in claim 1. Accordingly, it is possible to effectively guide oil which has spattered in multiple directions to the oil receiver by means of the oil guide plate and to improve oil recovery efficiency. In addition, since the oil receiver is positioned above the gear engagement part, oil drops by gravity and thereby the gear engagement part can be lubricated effectively. As a result, it is made possible to improve lubrication performance in an engine.
In the present invention as set forth in claim 3, the oil guide plate has at its upper portion a bent-upper edge part for guiding the scooped oil to the oil receiver, the bent-upper edge part being tilted and the upper edge thereof bent in a direction away from the oil receiver, in the invention set forth in one of claims 1 and 2. Accordingly, it is made possible to smoothly guide the scooped oil by means of the bent-upper edge part and to highly effectively guide the oil to the oil receiver.
[15]
In the present invention as set forth in claim 4, a roof plate for covering the guide plate in the side view thereof is arranged to the oil guide plate, and the roof plate has a structure for capturing oil which has been scooped up by the rotating member and for guiding the captured oil to the oil receiver in the invention set forth in any one of claims 1 to 3. Accordingly, the oil which has been scooped up by the rotating member and has been captured by the roof plate is efficiently guided to the oil receiver via the oil guide plate and is recovered.
[16]
In the present invention as set forth in claim 5, the roof plate is tilted in a way that oil is guided to the oil receiver by moving on the surface thereof, in the invention set forth in clam 4. Accordingly, the oil which has been scooped up by the rotating member moves on the surface of the roof plate and thereby the oil is efficiently guided to the oil receiver. [Best modes for carrying out the invention] [0017]
The oil accumulated in the lower part of a crankcase is scooped up by use of a rotator attached to a shaft of a transmission system, the shaft being rotated by a crankshaft. The oil which has been scooped up by the rotator is collected by use of a roof plate, and the collected oil is guided to an oil receiver by use of an oil guide plate. In this way, the present invention is carried out.
[Embodiment] [0018]
An embodiment of the present invention will be described on the basis of Figs. 1 and 10.
Pig. 1 shows a side view of a motorcycle which is a vehicle A to be mounted with an engine E where improvement in the lubrication of the present invention is to be applied. The motorcycle of the present invention includes a head pipe A1 as a frame member for the front thereof. A front fork A2 is attached below the head pipe A1. A front wheel A3 is rotatively supported by the front fork A2 . Above the head pipe A1, a handle bar A4 is attached.

In addition, a mainframe A5 is connected to the head pipe Al, obliquely pointing downward and extending in a rear direction therefrom. At the rear upper portion of the mainframe A5, a seat rail A6 which extends in a rear direction and points in a substantially horizontal direction therefrom is attached. Moreover, at the rear end portion of the mainframe A5 which bends downward, a back stay A7 extending in a rear direction and pointing upward therefrom is attached. The rear end portion of the back stay A7 is connected to the rear side of the seat rail A6.
[20]
The front end portion of a swing arm A8 is pivotally supported in the vicinity of the attached portion of the back stay A7 to the mainframe A5 . A rear wheel A9, which is a driving wheel of the vehicle A, is supported at the rear side of the swing arm A8 . Further, a seat member A10 for a rider is attached on the seat rail A6 located in a rearward position of the mainframe A5. [0021]
Furthermore, the top end of a down tube All is connected to the head pipe Al. The downtube All points and extends in a downward direction and then extends substantially in a horizontal direction. The end portion thereof is connected to the bent end portion of the mainframe A5. The engine E is arranged in a space surrounded by the mainframe A5 and the downtube All, so that the engine E is held in the space. The space is formed below the mainframe A5. The engine E is supported by the mainframe A5 and the downtube All via supporting members. In this way, the engine E is mounted on the vehicle A which is an motorcycle. [0022]
Fig. 1 shows the engine E in a state of being mounted on the vehicle A. Fig. 1 also shows an inlet pipe El arranged on the rear upper portion of the engine E, an air cleaner Ell connected thereto, an exhaust pipe E2 which is arranged on the front side of the engine E and is passing the side of the engine E to extend in a rear direction, a muffler E21 connected to the rear side of the exhaust pipe E2, and the like. In addition, Fig. 1 shows a radiator E3 for cooling the engine E, which is arranged in the front side of the engine E, a blowby gas pipe E4, a kick starter pedal E5 and the like.
[23]
A structure outline of the engine E to be mounted on the above-described motorcycle will be described.
[24]
In Fig. 2, the principal portion of the engine E of the present invention is shown in cross-sectional view. As shown in this figure, the engine E includes a crankcase 10, a cylinder block 20 connected to the crankcase 10, a cylinder head 30 to be connected to the cylinder block 20 and a cylinder head cover 40 . These are clamped and fixed together by means of stud bolts and the like, thereby constituting the main structure of the engine E.
[25]
The crankcase 10 has a structure in which half cases 11 and 12are integrally connected to each other. The half cases 11 and 12 are formed by being divided in right and left. In the crankcase 10 in which these half cases 11 and 12 are combined, a crankshaft 1, a mainshaft 2 and countershaft 3 of a transmission system 6, which are extending in parallel with the crankshaft 1, and the like are rotatively bearing-supported. [0026]
The crankshaft 1 is supported by bearings la and lb and, to a crankpin lc thereof, a connecting rod Id is roratively attached via a bearing located at the large-end le thereof. A piston P is swingably attached to the small-end If of the connecting rod Id via a piston pin lg. In this embodiment, there is provided one piston P and the engine E of the present invention is a 4-cycle single cylinder engine.
[27]
A gear lh having relatively a small outer diameter is attached near the right end of the crankshaft 1. The gear lh is a drive gear lh to be engaged with a driven gear 2a. The driven gear 2a is one to be loosely fitted to the mainshaft 2 of the above-described transmission system 6. The driven gear 2a, which is loosely fitted to the mainshaft 2, is provided near the right end of the mainshaft 2 together with a clutch 2b. The clutch 2b is one which selectively transmits the rotation of the driven gear 2a to the mainshaft 2 by means of its open/close operation. In addition, the shaft part located between bearings 2c and 2d which rotatively support the mainshaft 2 is equipped with a plurality of gears 2e for shifting.
[28]
The countershaft 3 is equipped with a plurality of gears 3a, which selectively engages with the plurality of gears 2e equipped to the mainshaft 2 to rotate the countershaft 3 at a desired gear ratio. These gears 3a are equipped to the shaft part located between bearings 3b and 3c supporting the countershaft 3. Moreover, a sprocket 3d for driving the rear wheel A9 which is a driving wheel of the vehicle A is attached to the left end of the countershaft 3. [0029]
Accordingly, the rotation of the crankshaft 1 is transmitted to the mainshaft 2 via engagement between the drive gear lh and the driven gear 2a and further via the open/close clutch 2b. The rotation of the crankshaft 1, which has been transmitted to the mainshaft 2 is then transmitted to the countershaft 3 from the mainshaft 2 via appropriate and selective engagement between the plurality of gears 2e and 3a for shifting, which are equipped on the countershaft 3 and mainshaft 2.
[30]
The rotation transmitted from the mainshaft 2 to the countershaft 3, which is conducted via selective engagement of gears 2e and 3a, is used to rotate the countershaft 3 at a desired gear ratio. The gear ratio is based on the selection of the gears 2e and 3a to be engaged. The rotation of the countershaft 3 is transmitted to the driving sprocket 3d attached to the left end of the shaft 3, and is further transmitted to the rear wheel A9 which is a driving wheel for driving a vehicle (see Fig. 1) via an unillustrated driving chain or the like, thereby making it possible to allow the vehicle A to drive at a desired speed.
[31]
A cylinder hole 20a for the piston P is provided in the cylinder block 20. The engine E of this embodiment includes one piston P, and accordingly only one cylinder hole 20a is provided therein. As is well known, the piston P reciprocates in the cylinder hole 20a in conjunction with the motion of the connecting rod Id, the motion triggered by the rotation of the crankshaft 1.
[32]
In the cylinder head 30, a combustion chamber 3 0a is provided which is formed by the cylinder hole 20a of the cylinder block 20 and the concave located at the lower part of the cylinder head 30. Unillustrated openings for intake/exhaust are formed in this combustion chamber 30a. These openings respectively communicate with intake and exhaust paths. In addition, intake and exhaust valves 3 0b and 30c for opening/closing the openings, only parts of which are shown here, are disposed in the openings.

The cylinder head 30 includes valve mechanism for activating the intake and exhaust valves 30b and 30c and, a cam 30d, a camshaft 30e and the like which constitute the valve mechanism are disposed therein. The camshaft 3 0e is attached with a sprocket 30g for a timing chain 30f. The timing chain 30f is used to rotate the camshaft 30e with half the number of the rotation of the crankshaft 1. The cylinder head cover 40 is equipped to the upper part of the cylinder head 30.
[34]
The engine E of this embodiment generally includes such a structure that has been described above. However, the engine E further includes a characteristic lubrication structure. Hereinafter, this lubrication structure will be described.
[35]
As described hereinbefore, and as shown in Fig. 2 and in a diagram of Fig. 5, the crankcase 10 includes a structure in which the right and left divided half cases 11 and 12 are integrally connected to each other. In the crankcase 10, the crankshaft 1 is rotatively bearing-supported. The rotation of the crankshaft 1 is transmitted to the mainshaft 2 of the transmission system G via engagement between the drive gear lh and driven gear 2a and via the clutch 2b.
[36]
The rotation of the crankshaft 1, which has been transmitted to the mainshaft 2, is configured to be further transmitted to the countershaft 3 via engagement between the gears 2e and 3a for shifting. In the lubrication structure of this embodiment, the oil scooped up by the rotating part of the rotation transmission system is utilized to lubricate the gear engagement part G1 of the transmission system G of the engine E.
[37]
For the purpose of scooping up oil by means of the rotating part of the rotation transmission system, the clutch 2b on the mainshaft 2, which is a rotator having a maximum diameter in this rotation transmission system, is utilized in this embodiment. Accordingly, the lower part of the clutch 2b is dipped into oil accumulated in the lower part of the crankcase 10.
[38]
As shown in Figs. 3 and 4 and in the diagram of Fig. 5, there is provided a structure in which the oil, which has been scooped up by means of the rotation of the clutch 2b, is captured by oil capturing means and is recovered in an oil receiver 11A, and in which the recovered oil is supplied from the oil receiver 11A via oil paths 11C and 12C communicating with the oil receiver 11A in order to lubricate the gear engagement part G1 of the transmission system G. The oil paths 11C and 12C are located in the right and left divided half cases 11 and 12 of the divided crankcase 10.
[39]
In order to lubricate the gear engagement part G1 of the transmission system G, such a structure is adopted that can be understood from Fig. 6 showing the side view of the right half case. In other words, a structure is adopted in which the transmission system G is located below the recovered oil receiver 11A and is positioned immediately underneath an oil path 10C to be described later. The oil path C is one which is composed of the recovered oil paths 11C and 12C, is communicating with the recovered oil receiver 11A, and is crossing the crankcase 10 in the direction orthogonal to the front-back-direction of the vehicle. Here, in the drawing, reference numerals 4, 5 and 6 denote a shift drum, a balancer shaft and an oil pump, respectively.
[40]
As shown in Fig. 2 and in the diagram of Fig. 5, the clutch 2b is equipped to the right end of the mainshaft 2. While maintaining this state, the most part of the clutch 2b is configured to protrude to the outside from the side 11a of the right half case 11 of the divided crankcase 10, the side 11a being equipped with the clutch. The portion of the clutch 2b, protruding from the side 11a of the right half case 11, is completely covered with the case cover 13.
10041J
The outer shape of the case cover 13 has a bowl-shaped concave for covering a portion of the clutch 2b, the portion protruding from the right half case side 11a (see Figs. 2, 3 and 5) . An opening 13a of the cover 13, which substantially forms the opening of the bowl-shaped concave, is applied to the side 11a of the right half case 11 from outside, and is fixed thereto by means of appropriate fixing means such as bolts. In this way, the case cover 13 is attached to the side 11a of the half case 11. Moreover, the outer side of the case cover 13, which substantially forms a bottom 13b of the bowl-shaped concave of the case cover 13, is configured to have a complete sealed structure. The case cover 13 is attached to the side 11a of the right half case 11, and thereby the side 11a of the right half case 11 is completely covered.
[42]
As can be seen by referring to Figs. 2 to 5, the substantial depth of the concave of the bowl-shaped case cover 13 which covers the protruding portion of the clutch 2b is set. In addition, the ring-shaped inner surface 13c, which covers the circumference 2bl of the outside diameter of the clutch 2b, is substantially concentric with the circumference 2bl of the clutch 2b. The circumference 2bl of the outside diameter of the clutch 2b and the ring-shaped inner surface 13c of the case cover 13 are configured to face each other with a relatively narrow space interposed therebetween. As shown in Figs. 3 to 5, on the ring-shaped inner surface 13c of the upper part of this case cover 13, there is formed a groove-shape concave 13d obliquely crossing the ring-shaped inner surface 13c in the width direction.
[43]
This groove-shaped concave 13d is the means for capturing the oil which has been scooped up by means of the rotation of the clutch 2b, and is formed on the ring-shaped inner surface 13c corresponding to a predetermined upper portion of the case cover 13 as a groove 13e obliquely crossing the ring-shaped inner surface 13c in the width direction. The groove 13e is a structure which has been cut to have a certain width and depth. The structure of the ring-shaped inner surface 13c, in which the oil capturing means is provided, is positioned as a roof plate 14 which covers above an oil guide plate 15 when viewed from the side of the oil guide plate 15, the roof plate 14 cooperating with the oil guide plate 15 of oil recovering means to be described later (see Fig. 3).

The groove-shaped concave 13d which is the oil capturing means in the roof plate 14 is formed at a position where the oil, which has been scooped up by means of the rotation of the clutch 2b, can be most effectively captured. As for the optimal position for capturing the scooped up oil, the ring-shaped inner surface 13c corresponding to a certain upper portion of the case cover 13 is selected, the position located substantially above both the mainshaft 2 and countershaft 3 of the transmission system G when the crankcase 10 is viewed from the top thereof as shown in Fig. 5.
[45]
As described above, the groove-shaped concave 13d which is the oil capturing means in the roof plate 14 obliquely crosses the ring-shaped inner surface 13c of the case cover 13 in the width direction. More specifically, from the outside of the case cover 13 to the inside of the crankcase 10, that is, from the cover sealing side 13f, which is the right side of the case cover 13, to the cover opening side 13g which is the left side of the case cover 13 as shown in Figs. 3 to 5, the groove-shaped concave 13d obliquely crosses the ring-shaped inner surface 13c of the case cover 13 in the width direction. The groove-shaped concave 13d obliquely crosses the ring-shaped inner surface 13c in the width direction, so that the groove-shaped concave 13d can be brought in line with the rotation direction R of the clutch 2b.
[46]
The groove-shaped concave 13d, which obliquely crosses the ring-shaped inner surface 13c constituting the roof plate 14 in the above-described manner, is formed to have the following structure, of which the cross-sectional view is shown in Fig. 3B. That is, the structure is one which is formed by gouging the ring-shaped inner surface of the case cover 13 to have an arc-shaped groove with certain width and depth,the groove-shaped concave 13d extending in the crossing direction in a smooth curve. In addition, as can be seen from Fig. 3A, the top of the groove-shaped concave 13d, that is, the bottom 13h of the groove-shaped concave 13d is a structure which has a gentle curve and gets slightly higher from the cover sealing side 13f, which is the outside of the case cover 13, to the cover opening side 13g which is the inner side thereof. Specifically, the groove-shaped concave 13d is formed to have such a structure that has a gentle curve and in which the bottom 13h get deeper from the cover sealing side 13f, which is the outside of the case cover 13, to the cover opening side 13g which is the inside thereof.
[47]
The above-described structure of the groove-shaped concave 13d is the optimal structure for effectively capturing the oil which has been scooped up by means of the rotation of the clutch 2b. The oil which has been captured by the groove-shaped concave 13d is configured to be guided from the roof plate 14 side of the case cover 13 to the inner side of the crankcase 10 via the oil guide plate 15 to be described later, more specifically, is configured to be guided to the oil recovered oil receiver 11A, which is formed along the side 11a of the right half case 11 (see Figs. 3 to 5).
[48]
To the side 11a of the right half case 11 of the crankcase 10, there is formed the above-described recovered oil receiver 11A. The oil receiver 11A communicates with the groove-shaped concave 13d for capturing oil, which is formed in the roof plate 14 of the case cover 13 along the side 11a. As shown in Figs. 5 to 8 and the like, this recovered oil receiver 11A is
accordingly formed above the mainshaft 2 of the transmission system G, in the position slightly near the rear side of a vehicle. This is the position substantially above the gear engagement part Gl, where the shifting gears 2e and 3a are engaged with each other. The shifting gears 2e and 3a are located on the mainshaft 2 and countershaft 3 of the transmission system G. For reference purposes, reference numeral 7 in Fig. 8 denotes a breather pipe.
[49]
As shown in Figs. 3 and 6, the oil guide plate 15 is allowed to abut to a side lie of a divided space 11c and the recovered oil receiver 11A is covered therewith, thereby forming the oil guide plate 15 (see Figs. 3 and 6). Here, the side lie is the side 11a of the right half case 11 (see Fig. 3) , specifically, this is the side of the divided space 11c partitioned by a rib lib on the side 11a of the right half case 11 to which the clutch 2b is equipped (see Fig. 6) , more specifically, this is the side of the lower part lid of the divided space 11c partitioned by the rib lib, the position corresponding to the position substantially above the mainshaft 2 on the side 11a. This oil receiver 11A is placed at a position llf, which is near the rear side of a vehicle and is lower than the lower part lid of the divided space 11c covered with the oil guide plate 15.
[50]
In addition, the side lie of the lower part lid of the divided space 11c (see Fig. 3) is covered with the oil guide plate 15 . At the same time, the lower part 11 j of a small divided space Hi is covered with the oil guide plate 15. The small divided space lli is adjacent to the divided space 11c partitioned by the rib lib with a rib llg interposed therebetween and is partitioned by a rib llh. In this way, an oil receiver 11B is formed which is different from the recovered oil receiver 11A (see Fig. 6).
[51]
The oil receiver 11B is positioned above the mainshaft 2, which is slightly near the front side of a vehicle, and is
formed at a position Ilk which is lower than the lower position llj of the small divided space Hi. This one-step lower position Ilk of the small divided space is situated at a position further slightly lower than the lower position llf of the recovered oil receiver 11A. The oil receiver 11B is one provided for the injected oil and therefore is provided with an oil inlet 11m communicating therewith, which is shown in Fig.
9.
[52]
As shown in Figs. 10A and 10B, the oil guide plate 15 is a plate-like member formed of a relatively thin steel plate or the like. As described above, the plate 15 is allowed to abut the side 11a of the right half case 11 and is fixed thereto in such a way that the lower parts lid and llj of the divided spaces 11c and lli on the side 11a of the right half case 11 of the crankcase 10 are covered with the plate 15. The lower parts lid and llj are partitioned by the ribs lib, llg and llh (see also Figs. 3 and 5 and the like).

The oil guide plate 15 is attached via the following two points by means of bolts B: that is, an upper position 15a of the plate 15, which corresponds to the position above the mainshaft 2 and is slightly rear side of the plate 15 when the plate 15 is in the contact state; and a position 15b of the plate 15, which is lower and the forefront position and is also in the vicinity of the oil receiver 11B for the injected oil (see also Fig. 6) .
[54]
The oil guide plate 15 covers the lower parts lid and llj of the divided spaces 11c and lli which are partitioned by the ribs lib, llg and llh on the right half case of the crankcase
10. Accordingly, when the oil guide plate 15 is viewed from the side, the outer shape thereof has a structure in which its lower shape 15A is brought in line with the ribs lib and llh substantially forming the lower parts lid and llj of the divided spaces 11c and lli. The outer shape of the oil guide plate 15 is also configured to include a center part 15c in the upper side thereof, which extends in the form of a substantially convex arc, and end parts 15d and 15e. The end parts 15d and 15e of the plate 15 further extend downward in the front- back-directions of a vehicle. Here, the center part 15c having a substantially convex arc is sandwiched by the end parts 15d and 15e.
[55]
Moreover, an upper shape 15B is configured to include the following structure: that is, a part of the plate 15, which is near the rear side of a vehicle, is a linear part 15f obliquely descending in the rear direction; a linear part 15g horizontally extending in the front-back-direction of the vehicle A is connected to this linear part 15f; and furthermore, a curve part 15h of the plate 15, which is near the front side of a vehicle and extending in the form of a segment of a circle, is connected to this linear part 15g. Accordingly, on the whole, the plate 15 has the shape that is similar to a sector when the plate 15 is viewed from the side. The linear part 15f of the upper shape 15B of the plate 15, which is near the rear side of a vehicle and is obliquely descending in the rear direction, is a bent- upper edge part 151 in which the upper edge thereof is bent in the direction away from the crankcase 10 (see also Fig. 10B).
[56]
In the state of installing the oil guide plate 15 on the side 11a of the right half case 11, by which the divided spaces 11c and 111 are covered, the lower spaces llf and Ilk of the divided spaces 11c and 111 are considered to be portions corresponding to the above-described two oil receivers 11A and 11B. Here, the lower spaces llf and Ilk are covered with the end parts 15d and 15e which further extend downward and in which the center part 15c having a convex arc is interposed therebetween.
[57]
In other words, the lower space llf of the divided space 11c is considered to be the recovered oil receiver 11A, the lower space llf being covered with the part 15d of the oil guide plate 15. The part 15d is located in the rear side and further extends downward when viewed from the front-back-direction of the vehicle A. Moreover, the lower space Ilk of the divided space lli is formed as the oil receiver 11B for the injected oil, the lower space lli being covered with the part 15e of the oil guide plate 15. The part 15e is located in the front side and further extends downward.
[58]
The bent-upper edge part 15i of the upper shape 15B of the oil guide plate 15 is positioned above the recovered oil receiver 11A. The bent-upper edge part 15i makes it easy to guide the oil flowing from the oil capturing groove-shaped concave 13d of the roof plate 14 to the recovered oil receiver 11A. This is achieved because the bent-upper edge part 15i has a bent structure bending in the direction away from the crankcase 10 and a linear structure 15f obliquely descending in the rear direction of the bent-upper edge part 15i. With this configuration, it is made possible to effectively guide the scooped oil to the recovered oil receiver 11A.
[59]
In addition, the curve part 15h of the oil guide plate 15, which points to the front side of the vehicle A and extends downward in the form of a segment of a circle, is positioned just above the oil receiver 11B for the injected oil.
[60]
The recovered oil receiver 11A is communicated with the oil path 11C which extends in the direction orthogonal to the front-back-direction of the vehicle A and which crosses in the right half case 11 of the crankcase 10, specifically, as shown in the diagrams of Figs. 5 and 6, is communicated with the oil path 11C which allows the recovered oil to flow therein and extends in such a manner that it crosses in the half case 11 just above the gear engagement part G1 of the shifting gears on the mainshaft 2 and countershaft 3 of the transmission system G while maintaining parallel relation with both the shafts 2
and 3. Moreover, an oil path 10D2 serving to circulate and supply the injected oil also communicates with this recovered oil receiver 11A, which will be described later. [0061]
The recovery oil path 11C which crosses in the right half case 11 is communicated with and connected to the oil path 12C similarly extending and crossing in the left half case 12 of the crankcase 10, resulting one oil path 10C in which these paths are communicated with and connected to each other to substantially form single-piece structure. As a result, the oil path 10C crossing in the crankcase 10 has the following structure: that is, the oil path 10C extends above the gear engagement part G1 and has a length that is enough to hold the entire length of the gear engagement part G1 of the shifting gears on the mainshaft 2 and countershaft 3 of the transmission system G. In this way, the recovery oil path 10C is formed which crosses in the crankcase 10 consisting of the right and left divided half cases 11 and 12. [0062]
As described above, the recovery oil path 10C, crossing in the crankcase 10, passes above the gear engagement part G1 of the transmission system G. In this oil path 10C, there is formed oil dropping means for dropping and supplying the recovered oil running through the oil path to the gear engagement part Gl. In this embodiment, there are formed dropping holes 10C1 through which oil is dropped (see Figs. 3 and 5). The dropping hole 10C1 has a predetermined diameter, and the plurality of dropping holes 10C1 is appropriately formed and opened along the path 10C at a predetermined intervals in the front-back-direction. However, the size and shape of the dropping hole 10C1, furthermore, the number of the dropping hole 10C1 and the intervals between the dropping holes 10C1 and the like are set as appropriate. [0063]
Moreover, as can be seen from the diagram of Fig. 5, the injected oil receiver 11B is communicated with an oil path 11D through which the injected oil flows, as similar to the recovered oil receiver 11A. Here, the oil path 11D extends in the direction orthogonal to the front-back-direction of the vehicle A and crosses in the right half case 11 of the crankcase
10. As described above, and as apparent from the references of Fig. 6 and the like, the injected oil receiver 11B is located at a position that is slightly lower than the recovered oil receiver 11A. Accordingly, the injected oil path 11D is also located at a position that is slightly lower than the recovered oil path 11C, and is extending and crossing in the half case
11. Although not shown in Fig. 5, this oil receiver 11B is communicated with the oil inlet 11m (see Fig. 9) through which oil is injected as described above.

The oil path 11D crossing in the divided right half case 11 is communicated with and connected to an oil path 12D which likewise extends and crosses in the left half case 12 of the crankcase 10, resulting one oil path 10D in which these paths are communicated with and connected to each other to substantially form single-piece structure. The oil path 10D forms the injected oil path 10D which crosses in the crankcase
10 consisting of the right and left divided half cases 11 and
12. A part of the injected oil flowing through the injected
11 path 10D is supplied to the mainshaft 2 via a path. A part of the path is not illustrated here. The other part of the oil is circulated and supplied to the recovered oil receiver 11A via a connection path 12D1 and a second injected oil path 12D2, which are described later.
[65]
As can be seen from the above statements, the two paths cross in the crankcase 10 consisting of the right and left divided half cases 11 and 12. That is, the recovered oil path 10C and the injected oil path 10D are in parallel with each other and crossing in the crankcase 10 while maintaining a predetermined interval therebetween. As shown in Fig. 5, in the crankcase 10, there is formed an oil path 10D2 crossing in
the crankcase 10. The oil path 10D2 is different from the recovered oil path 10C and the injected oil path 10D. [0066]
One end of this oil path 10D2 is communicated with the connection path 12D1 which is formed inside the left side wall of the left half case 12 shown in the drawing and which is connected to the above-described injected oil path 10D crossing in the crankcase 10. The other end of the oil path 10D2 is communicated with the recovered oil receiver 11A of the right half case 11. The oil which has been injected into the injected oil receiver 11B via this oil path 10D2 is configured to be circulated and supplied to the recovered oil receiver 11A. This oil path forms the second oil path 10D2.
[67]
An overflow hole X for ejecting excess oil is provided to the side of the right half case 11, the side corresponding to a slightly lower part of the gear engagement part Gl in the transmission system G of the mainshaft 2 and countershaft 3, more specifically, the side corresponding to a slightly lower part of the gear engagement part Gl that is located substantially beneath the recovered oil receiver 11A when the half case 11 is viewed from the side. In this embodiment, the overflow hole X is only provided in the right half case 11 shown in Figs. 6 to 8. However, a similar overflow hole can also be provided in the left half case 12.
[68]
Here, on the basis of Figs. 3 to 5, brief descriptions will be added for explaining the recovery of the oil which has been scooped up by the clutch 2b and for explaining the effect of lubrication using this oil.
[69]
It is to be noted that the rotating member, the oil path, the oil guide plate and the roof plate, which are described in the claims, are equivalent to the clutch 2b, the oil path 11C, the oil guide plate 15 and the roof plate 14, respectively.
[70]
H103-3630
The oil which has been scooped up by means of the rotation R of the clutch 2b attached to the mainshaft 2 is captured by the roof plate 14 of the case cover 13, that is, by the structure provided with the groove-shaped concave 13d formed on the predetermined upper portion of the ring-shaped inner surface 13c of the case cover 13. The scooped oil flows in such a way that it obliquely crosses the ring-shaped inner surface 13c along the groove-shaped concave 13d.
[71]
The captured oil that flows along the groove-shaped concave 13d is effectively guided by the structure of the groove 13e, which extends in a smooth curve and in which its bottom 13h gradually deepens from outside to the crankcase 10 side. The oil is then allowed to flow toward a crankcase 10 side open-end of the groove-shaped concave 13d, which is formed at an upper portion of the oil guide plate 15.

The oil which has reached the crankcase 10 side-open-end of the groove-shaped concave 13d is guided by the bent part of the bent-upper edge part 15i, which bends in the direction away from the crankcase 10 located behind (left) the oil guide plate 15. This oil then flows along an inclined plane 15 pointing to the rear side of the bent-upper edge part 15i, and then is guided to the recovered oil receiver 11A from the side 11a of the right half case 11.
[73]
The recovered oil which has been guided to the recovered oil receiver 11A flows along the recovered oil path 11C of the right half case 11, and flows toward the recovered oil path 12C of the left half case 12 . In this flowing process, the oil drops by gravity from the plurality of oil dropping holes 10C1 formed in the recovered oil paths 11C and 12C to the gear engagement part Gl of the mainshaft 2 and countershaft 3 of the transmission system G located below the paths 11C and 12C, thus the lubrication of the gear engagement part Gl is achieved.
Furthermore, this embodiment adopts such a configuration that allows the recovered oil to flow by means of the plurality of oil dropping holes 10C1. However, a configuration maybe adopted in which such dropping holes are not provided in the recovered oil paths 11C and 12C and the oil overflowed in the recovered oil paths 11C and 12C begins to come out from their edges.
[74]
Meanwhile, the oil which has been injected from the oil inlet 11m (see Fig. 9) floods into the injected oil receiver 11B, flows from the injected oil receiver 11B along the injected oil path 11D of the right-side half case 11, flows through the injected oil path 12D of the left half case 12, and crosses crankcase 10 consisting of the right and left divided half cases 11 and 12. A part of this oil is then supplied to the mainshaft 2 from an opening 12E (see Fig. 2) via an unillustrated path communicating with the injected oil path 12D.
[75]
The other part of the oil flows from the injected oil path 12D into the connection path 12D1 which is located inside the left side wall of the left half case 12 shown in Fig. 5 . However, since the injected oil receiver 11B and injected oil paths 11D and 12D are located at positions that are slightly lower than the recovered oil receiver 11A and the recovered oil paths 11C and 11D, only the injected oil in which the liquid level is in excess of certain limits is allowed to flow into the connection path 12D1.
[76]
The oil flowed into the connection path 12D1 makes U-turn after passing through the connection path 12D1. This oil again flows through the second injected oil path 10D2 crossing the crankcase 10, is circulated and supplied to the recovered oil receiver 11A of the right half case 11, meets the aforementioned recovered oil in this recovered oil receiver 11A, follows the above-described path of the recovered oil, and is supplied to the gear engagement part G1 of the transmission system G for the aforementioned lubrication.
In the embodiment of the present invention, the groove-shaped concave 13d of the roof plate 14 crosses in the oblique direction while facing the circumference 2bl and pointing to the rotation direction of the clutch 2b, and has a structure that deepens gradually from outside to inside with a gentle slope. Accordingly, it is possible to effectively capture the oil which has been scooped up by means of the rotation of the clutch 2b and to facilitate the smooth guidance of the captured oil.
[78]
The oil guide plate 15 includes the bent-upper edge part 15i which points to the lower adjacent part of the groove - shaped concave 13d of the roof plate 14 in the oblique and backward direction and which is bent in the direction away from the crankcase 10 side. Accordingly, the flowing oil which has been guided by the groove-shaped concave 13d of the roof plate 14 is further smoothly guided by the bent-upper edge part 15i and runs down along the bent-upper edge part 15i . In this way, this oil is effectively guided to the recovered oil receiver 11A.
[79]
The recovered oil receiver 11A is communicated with the recovered oil path 10C crossing the crankcase 10. The plurality of oil dropping holes 10C1 is formed and opened in the path 10C. Oil drops from these holes by gravity and thereby the gear engagement part Gl is lubricated. Accordingly, simple and reliable lubrication of the gear engagement part Gl can be achieved without any extra cost.
[80]
The oil in the injected oil path 10D is guided to the recovered oil receiver 11A via the connection path 12D1 and the second injected oil path 10D2. Accordingly, oil shortage in the recovered oil path 10C crossing the crankcase 10 is resolved, leading to effective and reliable lubrication of the gear engagement part Gl. [Industrial applicability]
In the embodiment of the present invention, the engine having the lubrication structure of the present invention is considered to be an engine for motorcycles . However, the engine having this lubrication structure is not limited to an engine for motorcycles, and accordingly can be used in other similar vehicles.
[Brief description of the drawings] [0082]
[Fig. 1] Fig. 1 is a side view showing the whole of a vehicle mounted with a engine having a lubrication structure of the present invention.
[Fig. 2] Fig. 2 is a cross-sectional view showing the principle structure of the engine of the present invention. [Fig. 3A] Fig. 3A is a side view showing the principle structure of the present invention.
[Fig. 3B] Fig. 3B is a cross-sectional view taken along A-A line in Fig. 3A.
[Fig. 4] Fig. 4 is a cross-sectional view taken along B-B line in Fig. 3, which shows the principle structure of the present invention.
[Fig. 5] Fig. 5 is an explanatory diagram showing the principle structure of the present invention.
[Fig. 6] Fig. 6 is a side view showing a right half case of a crankcase of the present invention.
[Fig. 7] Fig. 7 is a side view showing the right half case of the crankcase of the present invention, which is similar to Fig. 6.
[Fig. 8] Fig. 8 is a view showing another side of the right half
case of the crankcase of the present invention.
[Fig. 9] Fig. 9 is a view showing the outside of the right half
case of the crankcase of the present invention.
[Fig. 10A] Fig. 10A is a side view showing an oil guide plate
of the present invention.
[Fig. 10B] Fig. 10B is a cross-sectional view taken along C-C line in Fig. 10A.
[Explanation of reference numerals] [0083]
1...crankshaft 2b....clutch 10...crankcase
11A...recovered oil receiver
11C, 12C... recovered oil path
14...roof plate
15...oil guide plate
15i...bent-upper edge part

[Name of document] Claims [Claim 1]
A lubrication structure in an engine, which includes:
a crankcase having an oil pan at its lower position; a crankshaft which is rotatively supported in the crankcase;
a rotating member which rotates in conjunction with the crankshaft and which scoops up oil in the oil pan located at the lower position of the crankcase;
an oil receiver for receiving oil which has been scooped up by means of the rotating member; and
an oil path for circulating oil in the crankcase for lubrication, the oil having been received by the oil receiver, wherein the oil receiver has an oil guide plate for guiding oil to the oil receiver, the oil having been scooped up by the rotating member. [Claim 2]
The lubrication structure in an engine according to claim 1, wherein the oil guide plate is capable of guiding the scooped oil to the oil receiver by allowing the oil guide plate to abut the oil receiver, and the oil receiver is positioned above a gear engagement part of a transmission system. [Claim 3]
The lubrication structure in an engine according to one of claims 1 and 2,
wherein the oil guide plate has at its upper portion a bent-upper edge part for guiding the scooped oil to the oil receiver, the bent-upper edge part being tilted and the upper edge thereof bent in a direction away from the oil receiver. [Claim 4]
The lubrication structure in an engine according to any one of claims 1 to 3,
wherein, to the oil guide plate, there is arranged a roof plate for covering the guide plate in the side view thereof, and the roof plate has a structure for capturing oil which has been scooped up by the rotating member and for guiding the
captured oil to the oil receiver. [Claim 5]
The lubrication structure in an engine according to claim 4, wherein the roof plate is tilted in a way that oil is guided to the oil receiver by moving on the surface thereof.

Documents:

220-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 09-01-2013.pdf

220-CHE-2005 POWER OF ATTORNEY 09-01-2013.pdf

220-CHE-2005 AMENDED PAGES OF SPECIFICATION 09-01-2013.pdf

220-CHE-2005 AMENDED CLAIMS 09-01-2013.pdf

220-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 27-06-2012.pdf

220-CHE-2005 FORM-3 09-01-2013.pdf

220-CHE-2005 OTHER PATENT DOCUMENT 09-01-2013.pdf

220-CHE-2005 ABSTRACT.pdf

220-CHE-2005 CLAIMS.pdf

220-CHE-2005 CORRESPONDENCE OTHERS.pdf

220-CHE-2005 DESCRIPTION (COMPLETE).pdf

220-CHE-2005 DRAWINGS.pdf

220-CHE-2005 FORM 1.pdf

220-CHE-2005 FORM 18.pdf

220-CHE-2005 FORM 3.pdf

220-CHE-2005 FORM 5.pdf

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Patent Number

256018

Indian Patent Application Number

220/CHE/2005

PG Journal Number

17/2013

Publication Date

26-Apr-2013

Grant Date

19-Apr-2013

Date of Filing

08-Mar-2005

Name of Patentee

HONDA MOTOR CO., LTD.

Applicant Address

1-1 MINAMIAOYAMA 2-CHOME, MINATO-KU,TOKYO,

Inventors:

#	Inventor's Name	Inventor's Address
1	HAMADA , YASUNOBU.	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1,CHUO 1-CHOME, WAKO-SHI, SAITAMA,
2	TAKAHASHI , ISAMU ,	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, 4-1,CHUO 1-CHOME, WAKO-SHI, SAITAMA,

PCT International Classification Number

F01M 1/08

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2004-066241	2004-03-09	Japan