Title of Invention

MOTORCYCLE CRANKSHAFT LUBRICATING STRUCTURE

Abstract

ABSTRACT OF THE INVENTION A MOTORCYCLE ENGINE CRANKSHAFT LUBRICATING STRUCTURE A motorcycle engine crankshaft lubricating structure with a side plate (71) defining an oil sump (61) communicating with an outer surface of a crank pin l0p is fitted at an outer end of a crank web l0w, and with a feeding oilway (58) communicating with an oil pump (32) further communicating with the oil sump (61), wherein communication between the feeding oilway (58) and the oil sump (61) is carried out via oil grooves (59) formed at an outer surface of a crank journal 10ji supported at the crankcase 6 via a bearing 151.

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] PROVISIONAL/COMPLETE SPECIFICATION [See Section 10] "MOTORCYCLE CRANKSHAFT LUBRICATING STRUCTURE " HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan,, 1-1, Minamiaoyama 2-chome,, Minato-ku, Tokyo, Japan The following specification particularly describes the nature of the invention and the manner in which it is to be performed :- ORIGINAL 333/MUMNP/2000 GRANTED 7-5-2005 [Field of the Invention] The present invention relates to a;motoreycle eublulcating crankshaft structure mainly for lubricating an outer surface of a crank pin at an engine crankshaft, and more particularly relates to a superior crankshaft feeding oilway structure where a side plate defining an oil sump communicating with an outer surface of a crank pin is fitted at an end surface of a crank web, and a feeding oilway communicating with the oil pump communicates with the oil sump. [Related Art] Related crankshaft feeding oilway structures such as that disclosed in, for example, Japanese Utility Model Publication Laid-open No. 57-45460 are already well known. [Problems to be Solved by the Invention] In the feeding oilway structure described in the aforementioned publication, a curved oil hole reaching from an end of a crankshaft to an oil sump has to be made at the crankshaft in order that a feeding oilway extending from the oil pump communicates with the oil sump. However, the process of making this curved oil hole has to be carried out with a drill from two directions. This processing takes a long time and prevents costs from being reduced. In order to resolve the aforementioned situation, it is therefore the object of the present invention to provide a crankshaft feeding oilway structure in which communication between the oil sump and the feeding oilway is possible using a groove which is extremely simple to make, so that costs can be reduced accordingly. [Means for Resolving the Problems] In order to achieve the aforementioned object, in a first aspect of the present invention there is provided a moturcycle entine crankshaft structure with a side plate defining an oil sump communicating with an outer surface of a crank pin is fitted at an outer end of a crank web, and with a feeding oilway communicating with an oil pump further communicating with the oil sump, wherein communication between the feeding oilway and the oil sump is carried out via oil grooves formed at an outer surface of a crank journal supported at the crankcase via a bearing. According to the first aspect, communication between the feeding oilway and the oil sump is simplified, crankshaft productivity is increased and cost is reduced because the process of making the oil grooves at the outer surface of the crank journal is simplified. In addition to the first aspect, in a second aspect of the present invention the oil grooves are formed parallel with a crankshaft journal axis. According to this second aspect, the oil grooves are formed at the same time as the forging of the crankshaft. A special groove-forming process is therefore not required and crankshaft productivity is increased In addition to the second aspect, in a third aspect of the present invention, the oil grooves are located at a position phase-shifted by approximately 90 degrees to the crank pin withrespect to the center of rotation of the crank journal. According to the third aspect, when the piston reaches top dead center and bottom dead center, the oil grooves are positioned in a plane orthogonal to the axis of a cylinder bore. The application of a vertical load from the piston in the vicinity of the oil grooves, are therefore avoided and the lowering in the strength of the crank journal due to the presence of the oil grooves is prevented. In addition to the first to third aspects, in a fourth aspect of the present invention, the crank journal is formed with a larger diameter than a journal outer shaft section extending further outwards, inlets of the oil grooves open at an annular step between the crank journal and the journal outer shaft section, an annular oil chamber faced by the outer surface of the bearing and the inlet of the oil grooves are defined by the crankcase supporting,the bearing, and the feeding oilway is connected to the oil chamber. According to this fourth aspect, the bearing supporting the crank journal can be lubricated by lubricating oil flowing into an annular oil chamber from the feeding oilway, lubricating oil of the annular oil chamber can be communicated directly to the oil grooves without being subjected to centrifugal force, and lubrication of the crank pin can be carried out in a smooth manner. [Brief Description of the Drawings] FIG. 1 is a side view of a front part of a motorcycle to which the present invention is applied. FIG. 2 is a cross-section taken along line 2-2 of FIG. 1. FIG. 3 is a cross-section taken along line 3-3 of FIG. 2. FIG. 4 is a cross-section taken along line 4-4 of FIG. 3. FIG. 5 is a cross-section taken along line 5-5 of FIG. 3. FIG. 6 is a cross-section taken along line 6-6 of FIG. 3. FIG. 7 is an enlarged view of the surroundings of the oil pump of FJG. 3. FIG. 8 is a cross-section taken along line 8-8 of FIG. 7. FIG. 9 is an exploded perspective view of a crankshaft. FIG. 10 is a perspective view of a cover. [0014] [Embodiments] A description is now given of practical examples of the present invention based on an embodiment of the present invention shown in the appended drawings. FIG. 1 is a side view of a front part of a motorcycle to which the present invention is applied, FIG 2 is a cross-section taken along line 2-2 of FIG. 1, FIG. 3 is a cross-section taken along line 3-3 of FIG. 2, FIG. 4 is a cross-section taken along line 4-4 of FIG. 3, FIG. 5 is a cross-section taken along line 5-5 of FIG. 3, FIG. 6 is a cross-section taken along line 6-6 of FIG. 3, FIG. 7 is an enlarged view of the surroundings of the oil pump of FIG. 3, FIG. 8 is a cross-section taken along line 8-8 of FIG. 7, FIG. 9 is an exploded perspective view of a crankshaft, and FIG. 10 is a perspective view of a cover. First, in FIG. 1, a motorcycle 1 is a scooter-type motorcycle, a power unit P for driving a rear wheel Wr is fitted to the rear part of a body frame 2 of the motorcycle 1 and is capable of freely rocking up and down via a link 9, and a shock absorber 3 is interposed between the power unit P and the body frame 2. As shown in FIG. 2, the power unit P comprises a water-cooled four-cycle engine 4 and a belt-type infinitely variable transmission 5 coupled to the left side-surface of the engine 4. The rear wheel Wr is mounted at a position immediately after the engine 4 at a side of the rear end of the infinitely variable transmission 5. In FIG. 2 to FIG. 4, the crank case 6, cylinder block 7 coupled at the front surface of the crank case 6 and arranged in a substantially horizontal manner, and a cylinder head 8 joined to the upper surface of the cylinder block 7 constitute the engine body of the engine 4. A crankshaft 10 housed in and supported by the crank case 6 is connected to a piston 11 moving up and down within a cylinder bore 7a of the cylinder block 7 via a connecting rod 12. A well-known valve gear 74 including a camshaft 14 driven by a crankshaft 10 via a timing transmission assembly 13 and an inlet valve 72 and exhaust valve 73 are provided in the cylinder head 8 (refer to FIG. 4). The crankcase 6 comprises a front case half 6a continuing on integrally from the cylinder block 7 and a rear case half 6b bolted onto the front case half 6a. Left and right ciank journals l0j, and !0j:, of the crankshaft !0 are then sandwiched between the crankcase halves 6a and 6b via ball bearings 151 and 152, respectively. A drive pulley 16 of the infinitely variable transmission 5 is attached to a journal outer shaft section 10e extending outwards from the left crank journal 10j1. and a transmission case 17 is bolted to the left end of the crank case 6. A transmission chamber 18 in which the timing transmission assembly 13 is located and a cylindrical auxiliary chamber 19 adjacent to the outer side of the transmission chamber 18 are formed at the right end of the crank case 6 on the opposite side to the infinitely variable transmission 5. An oil seal 21 tightly fitting with the outer surface of the crankshaft 10 is mounted at a bulkhead 20 between the transmission chamber 18 and the auxiliary chamber 19. As shown in FIG. 3 and FIG. 5, a stator 22s of a generator 22 (accessory) is fixed using a plurality of bolts 23 (refer to FIG. 5) to a plurality of bosses 19a projecting from the inner wall of the auxiliary chamber 19, and a rotor 22r fixed to the right end of the crankshaft 10 by bolts 24. An auxiliary chamber cover 25 and a fan cover 26 are sequentially connected to the right end of the crank case 6, an engine cooling radiator 28 is fitted to the outer end of the fan cover 26, and a cooling fan 27 for cooling the radiator 28 and the generator 22 is positioned within the fan cover 26. The cooling fan 27 is fixed together with the rotor 22r to the crankshaft 10 by the bolts 24. As shown in FIG. 3 and FIG. 4, the lower part of the crankcase 6 forms an oil sump 29 and lubricating oil 30 accumulated in the oil sump 29 is sucked into an oil pump 32 •through an oil filter 31 and sent under pressure to the crankshaft 10 and other parts of the engine by the pump 32. A cylindrical filter chamber 33 opening at a front surface is formed at the lower part of the front case half 6a and houses the cup-shaped oil filter 31 and a support spring 35 that presses a seal member 34 attached to the open end of the oil filter 31 against the back wall of the chamber 33, with a cap 36 being screwed into the opening of the filter chamber 33. [0026] The filter chamber 33 is partitioned by the oil filter 31 into a dirty chamber within the oil filter 31 and a clean chamber outside the oil filter 31. An intake oilway 37 extending from the oil sump 29 is connected to the dirty chamber and an intake port 32i of the oil pump 32 communicates with the clean chamber via an outlet oilway 38. If the cap 36 is removed, the oil filter 31 can be taken out and cleaned and lubricating oil 30 within the oil sump 29 can be discharged to outside through the filter chamber 33, i.e. the cap 36 doubles as a drain bolt. In FIG. 7 the oil pump 32 is fitted to an inner wall of the transmission chamber 18 on the opposite side to the bulkhead 20. The oil pump 32 is equipped with a pump housing 40, pump rotor 41 housed within the pump housing 40 and pump cover 42 connected to the open face of the pump housing 40. The intake port 32i and an outlet port 32o are provided at the pump cover 42. The pump housing 40 and the pump cover 42 are fixed to the inner wall of the transmission chamber 18 using bolts 43 at the inner side of the cover 42. A pump shaft 46 that penetrates a pump housing bearing hole 45 of the pump housing 40 is fitted at and coupled to a communicating hole 44 of the pump rotor 41. A boss 48a of the drive gear 48 is then fitted at the pump shaft 46 and is coupled via a joint pin 68. i.e., as shown in FIG 8, the joint pin 68 is fitted at the pump shaft 46 in such a manner as to transverse the pump shaft 46 and couple between the pump shaft 46 and the drive gear 48 by engaging with a key channel 69 at the end surface of the boss 48a of the drive gear 48. The driven gear 48 is driven at low speed by the drive gear 47 fixed to the crankshaft 10 at the transmission chamber 18 and is formed with a much larger diameter than the oil pump 32. A drive sprocket 49 of the timing transmission assembly 13 is integrally formed at the drive gear 47. A circular fitting hole 50 of substantially the same diameter as the oil pump 32, i.e. of a much smaller diameter than the driven gear 48, is provided at the portion of the bulkhead 20 facing the oil pump 32 in such a manner that the oil pump 32, and in particular, the bolts 43, can be detached from the auxiliary chamber 19 via the fitting hole 50. A cover 52 is fitted to the fitting hole 50 via a seal member 53. A saccate bearing hole 51 for rotatably supporting an outer end of the pump shaft 46 and limiting movement of the pump shaft 46 in an axial direction is provided at the inner surface of the cover 52. As shown in FIG. 10, a segmental flange 54 projecting radially from an outer peripheral edge of the cover 52 and a strut 55 projecting from the outside surface of the cover 52 are formed integrally with the cover 52. The cover is therefore supported at a fixed' position at the fitting hole 50 as a result of the flange 54 coming into contact with the bulkhead 20 at the auxiliary chamber 19-side and an end of the strut 55 pressing against the inner surface of the stator 22s via a resilient cap 56. The outlet port 32o of the oil pump 32 communicates with the outer surface of a crank pin 10p via a feeding oilway 58 formed at the front case half 6a, an oil chamber 60 faced by the outer surface of the ball bearing 15, bearing the left crank journal 10j,, oil grooves 59 formed at the outer surface of the left crank journal 1 0j,, an oil sump 61 provided at a crank web l0w extending integrally from the left crank journal 1 0j,, a hollow part 62 of the crank pin lOp, and radially-facing oil spout 63 provided at the crank pin l0p. The outer surface of the crank pin l0p which the oil spout 63 opens out to supports a big end 12b of the connecting rod 12 via a needle bearing 64 (refer to FIG. 4). The above oilway structure is now described in more detail. AN outer race of the ball bearing 15, supporting the left crank journal 1 Oj, is fitted at a infinitely variable transmission 5-side outer wall 65 of the crank case 6, an oil seal 66 is mounted in a close-fitting manner at a journal outer shaft section lOe, and the annular oil chamber 60 faced by the outside surface of the ball bearing 15, is defined by the outer wall 65 and the oil seal 66. The left crank journal 1 0j, has a larger diameter than the journal outer shaft section l0e that extends further outwards than the left crank journal lOj, and an annular step 67 that faces the oil chamber 60 is therefore formed between the left crank journal 10j, and the journal outer shaft section 1 0e. A pair of the oil grooves 59 that reach from the step 67 to the base of the left crank journal 10j, are provided at the outer surface of the left crank journal 10j,, with the open ends of these oil grooves 59 going to the step 67 then constituting inlets. The oil groove 59 is formed when forging the crankshaft 10 and in order to make this forming straightforward, as becomes clear from FIG. 6 and FIG. 9, is arranged at two locations about the center of rotation of the left crank journal 10j, parallel to the axis of the left crank journal 10jl phase-shifted by approximately 90 degrees with respect to the crank pin l0p. Further, a circular recess 70 is formed at the outside surface of the crank web l0w on the same side as the left crank journal 1 Oj, and an annular side plate 71 encompassing the left crank journal 10j, is press-fitted at the recess 70. The annular, flat oil sump 61 is then defined between the side plate 71 and the crank web lOw. The outlets of the oil grooves 59 then open at the inner side of the oil sump 61 in the radial direction and have the hollow part 62 of the crank pin lOp opening at a central part. As shown in FIG. 6, a second feeding oilway 58' diverging from the feeding oilway 58 is provided in the front case half 6a, the cylinder block 7 and the cylinder head 8, for supplying oil to the valve gear 74 via the second feeding oilway 58. The following is a description of the operation of this embodiment. Regarding the fitting of the oil pump 32 and its drive system, first, in the front case half 6a prior to the rear case half 6b being connected, the oil pump 32 is inserted into the transmission chamber 18, and the oil pump 32 is fitted to a prescribed location within the transmission chamber 18 the auxiliary chamber 19 using the bolts 43 inserted into the transmission chamber 18 through the fitting hole 50. Next, the large diameter driven gear 48 is inserted into the transmission chamber 18 of the front case half 6a so as to be next to the oil pump 32. The pump shaft 46 equipped with the joint pin 68 is then sequentially fitted into the boss 48a of the driven gear 48, the bearing hole 45 of the pump housing 40 and the communicating hole 44 of the pump rotor 41 in that order from the auxiliary chamber 19 through the fitting hole 50, and the joint pin 68 is made to engage with the key groove 69 of the boss 48a. Finally, the cover 52 with the seal member 53 mounted at its outer periphery is fitted to the fitting hole 50 of the bulkhead 20, the cover bearing hole 51 is fitted with the outer end of the pump shaft 46 and the flange 54 comes into contact with the outer surface of the bulkhead 20. The end of the strut 55 of the cover 52 is then covered with the reinforcing cap 56. The coupling of the driven gear 48 to the pump shaft 46 is therefore straightforward when the oil pump 32 is fitted to the inner wall of a narrow transmission chamber 18 even when the fitting hole 50 of the bulkhead 20 is of a smaller diameter than the driven gear 48. Reduction in the strength of the bulkhead 20 is therefore substantially avoided by having the fitting hole 50 of a smaller diameter than the driven gear 48 and brings about the benefits of being light in weight. Further, a member such as a clip, etc., dedicated to preventing the pump shaft, from coming away is no longer necessary because movement of the pump shaft 46, inserted through the driven gear 48, pump housing 40 and pump rotor 41, in the axial direction is restricted by the saccate cover bearing hole 51 of the cover 52 fitted to the fitting hole 50, and the structure can therefore be further simplified. Further, the cover bearing hole 51 of the cover 52, together with the bearing hole 45 of the pump housing 40, supports the pump shaft 46 on both sides of the driven gear 48 in a strong manner and thus contributes to improving the durability of the oil pump 32. When the entire engine is then assembled, the inner end surface of the stator 22s of the generator 22 fixed to the inner wall of the auxiliary chamber 19 of the crank case 6 presses against the end of the strut 55 of the cover 52 via the resilient cap 56 so that the cover 52 is supported in a fixed position with the flange 54 coming into contact with the outside surface of the bulkhead 20. A dedicated support member such as a bolt, etc., is therefore no longer necessary and this support structure can therefore be simplified. On the other hand, the drive gear 47 fixed to the crankshaft 10 meshes with the driven gear 48 so as to enable the oil pump 32 to be driven. When the engine is running, the drive gear 47 rotating together with the crankshaft 10 drives the driven gear 48 at low speed and the rotor 41 of the oil pump 32 can therefore be driven at an appropriate speed. The oil pump 32 operating in this manner then takes in lubricating oil 30 of the oil sump 29 via the oil filter 31 and sends this oil under pressure to the feeding oilway 58, oil chamber 60, oil grooves 59, hollow part 62 of the crank pin l0p and the oil spout 63. The ball bearing 151 supporting the left crank journal 10j, can therefore be lubricated at the oil chamber 60 and the outer surface of the crank pin 1 0p, the needle bearing 64 and the inner surface of the big end 12b of the connecting rod 12 can be lubricated at the crank pin l0p. Lubricating oil of the oil chamber 60 can therefore be communicated in a direct manner to the oil grooves 59 and oil can be supplied to the crank pin 1 0p in a smooth manner because the inlets of the oil grooves 59 open at the annular step 67 between the large-diameter left crank journal 10j, and the small diameterjournal outer shaft section l0e. The oil grooves 59 formed at the outer surface of the left crank journal 10j,, for communicating between the oil chamber 60 on the outside of the ball bearing 151 and the oil sump 61 on the outside of the crank web l0w can also be easily made. In particular, when the oil grooves 59 are arranged parallel with the axis of the left crank journal 10j,, the oil grooves 59 can be formed at the same time as the forging of the crankshaft 10. A special groove-forming process is therefore not necessary, productivity can be improved for the crankshaft 10 and cost reductions can be made. The oil grooves 59 on the outer surface of the left crank journal 10j, are located at a position phase-shifted by approximately 90 degrees from the crank pin l0p with respect to the center of rotation of the left crank journal 10j,. When the piston 11 then reaches top dead center and bottom dead center, the oil grooves 59 are then positioned in a plane orthogonal to the axis of the cylinder bore 7a. The application of a large vertical load from the piston 11 in the vicinity of the oil grooves 59 of the left ciank journal 10j, can therefore be avoided and a lowering of the strength of the left crank journal 10j, due to the oil grooves 59 can be avoided. The present invention is by no means limited to the aforementioned embodiment, and various design modifications are possible without deviating from the spirit of this invention as defined in the patent claims. For example, a plain bearing can be provided in place of the ball bearing 15, supporting the crank journal 1 0j,. The oil groove 59 and the oil sump 61 can also be provided at the right crank journal 10j2 and the crank web l0w. [Effects of the Invention] According to the first aspect of the present invention, there is provided a crankshaft feeding oilway structure with a side plate defining an oil sump communicating with an outer surface of a crank pin fitted at an outer end of a crank web lOw, and with a feeding oilway communicating with an oil pump 32 further communicating with the oil sump 61, wherein communication between the feeding oilway and the oil sump is carried out via oil grooves formed at an outer surface of a crank journal supported at the crankcase via a bearing. Communication between the feeding oilway and the oil sump can therefore be simplified because the making of the oil grooves on the outer surface of the crank journal is simplified, crankshaft productivity can be improved, and cost can be reduced. According to this second aspect of the present invention, the oil grooves can be formed at the same time as the forging of the crankshaft because the oil grooves are formed parallel with the axis of the crank journal, A special groove-forming process is therefore not required and crankshaft productivity is increased. According to the third aspect of the present invention, the oil grooves are positioned phase shifted by approximately 90 degrees from the crank pin with respect to the center of rotation of the crank journal. The application of a vertical load from the piston in the vicinity of the oil grooves are therefore avoided and the lowering in the strength of the rnal due to the presence of the oil grooves is prevented. In a fourth aspect of the present invention, the crank journal is formed with a larger diameter than a journal outer shaft section extending further outwards, inlets of the oil grooves open at an annular step between the crank journal and the journal outer shaft section, an annular oil chamber faced by the outer surface of the bearing and the inlets of the oil grooves are defined by the crankcase supporting the bearing, and the feeding oilway is connected to the oil chamber. The bearing supporting the crank journal can be lubricated by lubricating oil flowing into an annular oil chamber from the feeding oilway, lubricating oil of the annular oil chamber can be communicated directly to the oil grooves without being subjected to centrifugal force, and lubrication of the crank pin can be carried out in a smooth manner. [Description of the Numerals] crank case 6 crankshaft 10 journal outer shaft section l0e crank journal 10j, crank pin 1 0p crank web 1 0w bearing (ball bearing) 151 oil pump 32 feeding oilway 58 oil grooves 59 oil chamber 60 oil sump 61 step 67 side plate 71 We claim: 1. A motorcycle crankshaft lubricating structure with a side plate (71) defining an oil sump (61) communicating with an outer surface of a crank pin l0p is fitted at an outer end of a crank web l0w, and with a feeding oilway (58) communicating with an oil pump (32) further communicating with the oil sump (61), characterized in that the communication between the feeding oilway (58) and the oil sump (61) is carried out via oil grooves (59) formed at an outer surface of a crank journal lOji supported at the crankcase 6 via a bearing 15i. 2. The crankshaft as claimed in claim 1, wherein the oil grooves (59) are formed parallel with axis of the crank journal l0ji. 3. The crankshaft as claimed in claim 2, wherein the oil grooves (59) are positioned phase-shifted by 90 degrees from the crank pin lOp in relation to the center of rotation of the crank journal l0ji. 4. The crankshaft as claimed in any one of claims 1 to 3, wherein the crank journal l0ji is formed with a larger diameter than a journal outer shaft section l0e extending further outwards, inlets of the oil grooves (59) open at an annular step (67) between the crank journal l0ji and the journal outer shaft section l0e, an annular oil chamber faced by the outer surface of the bearing 151 and the inlets of the oil grooves (59) are defined by the crankcase (6) supporting the bearing 151, and the feeding oilway (58) is connected to the oil chamber (60). 5. A motorcycle crankshaft lubricating structure substantially as herein described with reference to the accompanying drawings. Dated this the 11th day of April, 2000. (JAYANTA PAL) OF REMFRY & SAGAR ATTORNEY FOR THE PPLICANTS

Documents:

333-mum-2000-abstract(24-06-2005).doc

333-mum-2000-abstract(24-06-2005).pdf

333-mum-2000-cancelled pages(07-05-2005).pdf

333-mum-2000-claims(granted)-(07-05-2005).doc

333-mum-2000-claims(granted)-(07-05-2005).pdf

333-mum-2000-correspondence(06-06-2007).pdf

333-mum-2000-correspondence(ipo)-(07-07-2004).pdf

333-mum-2000-drawing(19-03-2001).pdf

333-mum-2000-form 1(11-04-2000).pdf

333-mum-2000-form 19(16-04-2000).pdf

333-mum-2000-form 2(granted)-(07-05-2005).doc

333-mum-2000-form 2(granted)-(07-05-2005).pdf

333-mum-2000-form 3(11-04-2000).pdf

333-mum-2000-form 3(24-06-2005).pdf

333-mum-2000-form 3(26-02-2001).pdf

333-mum-2000-form 5(11-04-2000).pdf

333-mum-2000-petition under rule 138(24-06-2005).pdf

333-mum-2000-power of attorney(04-09-2000).pdf

333-mum-2000-power of attorney(24-06-2005).pdf

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