Title of Invention	SADDLE-RIDING TYPE VEHICLE
Abstract	A motorcycle (10) includes a head pipe (15) that supports a steering shaft to rotationally move freely, a body frame (11) connected to the head pipe (15), and an engine (12) supported by the body frame (11) in a suspended state. The body frame (11) includes a main frame (19) that extends obliquely downward to the rear from the head pipe (15) and a pair of left and right sub-frames (20) that extend obliquely downward to the rear from the main frame (19) . The engine (12) includes a crankcase (l2b) and a cylinder (12a) that extends obliquely upward to the front from the crankcase (l2b) . The cylinder (12a) is supported by a rear end (19b) of the main frame (19) . The crankcase (l2o) is supported by portions in two places sewpatated to the front, and the rear in the respective sub-frames (20).

Title of Invention

SADDLE-RIDING TYPE VEHICLE

Abstract

A motorcycle (10) includes a head pipe (15) that supports a steering shaft to rotationally move freely, a body frame (11) connected to the head pipe (15), and an engine (12) supported by the body frame (11) in a suspended state. The body frame (11) includes a main frame (19) that extends obliquely downward to the rear from the head pipe (15) and a pair of left and right sub-frames (20) that extend obliquely downward to the rear from the main frame (19) . The engine (12) includes a crankcase (l2b) and a cylinder (12a) that extends obliquely upward to the front from the crankcase (l2b) . The cylinder (12a) is supported by a rear end (19b) of the main frame (19) . The crankcase (l2o) is supported by portions in two places sewpatated to the front, and the rear in the respective sub-frames (20).

Full Text	DESCRIPTION Saddle-riding Type Vehicle Technical Field [0001] The invention relates to a saddle-riding type vehicle such as a motorcycle. Background Art [0002] Conventionally, there is known a saddle-ridinq type vehicle including a head pipe that supports a steering handle to be capable of moving rotationally, a frame that extends obliquely downward to the rear from the headpipe, and an engine supported by the frame in a suspended state. As the saddle-riding type vehicle of this type, for example, motorcycles disclosed in Patent Documents 1 to 3 described below are known, [0003] The motorcycle disclosed, in the Patent Document 1 includes a head pipe and a pair of left atid right maim frames that extend obliquely downward to the rear from the head pipe. Brackets are coupled to rear portioms of the main frames, An engine is supported by the left and the right main frames and brackets in a suspended state. The motorcycle also includes rear swing arms that support a rear wheel The rear swing arms are supported by the brackets via. a pivot shaft to move up and 1 down freely, [0004] Patent Document 1. JP-A-08-067285 Patent Document 2: JP~A-05-330474 Patent Document 3: JP-A-03-330475 Disclosure of the Invention Problems that the Invention 15 to solve [0005] Incidentally, in such a saddle-riding type vehicle, it is desired to reduce weight of a body frame or reduce width of the vehicle while maintaining strength of the body frame. For improvement of convenience in getting on and off the vehicle, it is also desired to keep a portion ahead of a seat low. [0006] However, in the conventional saddle-riding type vehicle, the engine is supported by the pair of left and right main frames and brackets in an upper part and a rear part of a crankcase of the engine. Consequently, the main frames and the brackets are required to have rigidity that is large to some extent. Therefore, in order to secure rigidity of the main frames and the brackets, it is necessary to increase thickness of the main frames and the brackets. However, when thickness of the main frames and the like is increased, it is difficult to reduce weight of the body frame [0007] In the conventional saddle-ridinq type vehicle, both. the engine and the rear swing arms ate held between the pair of left and right brackets. Consequently, an interval between 2 the left and the right brackets is increased and the main frame sticks out in the Left to right direction. Therefore, it is difficult to reduce width of the vehicle (a reduction in width in a vehicle Width direction). [0008] Thus, it is an object of the invention to realize a reduction in weight of a body frame while maintaining strength of the body frame in a saddle-riding type vehicle. It is another object of the invention to realize a reduction in width of the vehicle while maintaining strength of the body frame. It is still another object of the invention to keep a portion ahead of a seat of the vehicle low. Means for salving the Problems [0009] A saddle-riding type vehicle according to the invention includes: a head pipe that supports a steering shaft to rotationally move freely: a body frame including a main frame that is connected to the bead pipe and extends obliquely- downward to the rear and a pair of left and right sub-frames that are connected to the main frame and extend obliquely downward to the rear; and a motor supported by the main frame and the respective sub-frames in a suspended state. [0010] According to the saddle-riding type vehicle, the motor is supported by the main frame and both the sub-frames, whereby the motor is arranged to be laid over the main frame and both the left and the right sub-frames- As a result, since the main frame and the sub-frames are reinforced by the motor, it is 3 possible to keep strength of the main frame itself or the sub-frames themselves low because of reinforcement by the motor. Therefore, it is possible to resalize a seduction in a size or a reduction in weight of the body frame while maintaining strength of the body frame. [0011] It is preferable that a connecting portion of the main frame ancl the sub-frames is located ahead of a portion supporting the motor in the main frame. [0012] Consequently, a portion between a front end portion of the main frame and a portion supporting the motor 15 reinforced by the sub-frames. Thus, strength of the main frame is improved. Note that a necessary strength distribution of the main frame differs for each vehicle. However, it is possible to make a strength distribution of the main frame suitable or optimum by adjusting a connecting position of the sub-frames to the main frame appropriately. [0013] It is preferable that the head pipe is connected to a front end side of the main frame and a cross sectional area of the main frame changes along a longitudinal direction of the main frame such that the front end side is larger than a rear end side. [0014] Note that the change in the cross sectional area of the main frame may be continuous or stepwise along the longitudinal direction of the main frame. A form of the change in the cross sectional area is not specifically lumited. 4 [0015] Consequently, the main frame is formed relatively thick on the front end side connected to the head pipe. Thus, it is possible to secure larger strength of the main frame against bending moment. On the other hand, since the rear end of the main frame is formed relatively thin, when a body cover on a front side of the seat is arranged above the rear end of the main frame, it is possible to keep the body cover low. [0016] It is preferable that the main frame supports the motor at the rear end of the main frame. [0017] Consequently, it is possible to reduce length of the main frame. [0018] It is possible that the sub-frames are bent convexly downward and support the motor at least in one place near bent portions. [0019] Consequently, the motor functions as a reinforcing member to increase strength of the bent portions of the sub-frames. Since the strength of the sub-frames increases. it is possible to realize a reduction in a size or a reduction in weight of the sub-frames. Since it is possible to reduce a size of the sub-frames, it is possible to keep the body cover on the front side of the seat low. [0020] It is preferable that the sub-frames are bent convexly downward and support the motor at least in one place further on a rear side than the bent portions. [0021] Consequently, the motor functions as a reinforcing 5 member and strength in portions further on the rear side of the bent portions in the sub-frames increases. Since the strength of the sub-frames increases, it is possible to realise a reduction in size and a reduction in weight of the sub-frames . Since it is possible to reduce a size of the sub-frames, it is possible to keep the body covet on the front side of the seat low. [0022] It is preferable that the saddle-riding type vehicle includes: a rear wheel; and rear arms that support the rear wheel and extend substantially in a front to rear direction, the sub-crams iS beat convexly downward, and both a part of the motor and the rear arms are supported at the rear ends of the sub-frames. [0023] Consequently, since a part of the motor 15 supported together with the rear arms, it is possible to simplify a supporting structure for the motor and the rear arms. Since the motor and the rear anus are supported together, in using brackets for support, it is possible to reduce a size of the brackets compared with a case in which the motor and the rear arms are supported separately. Since it is possible to reduce a size of the brackets in this way, it is possible to increase strength of the entire body frame. [0024] It is preferable that the sub-frames are bent convexly downward and the saddle-riding type vehicle further includes rear side frames that are connected to a portion further on 6 the rear side than the bent portions of the sub-frames and extand obliquely upward to the rear. [0025] Consequently, the rear side portions of the sub-frames are reinforced by the reer side frames, it is possible to reduce a size of the sub-frames because the sub-frames are rein forced. Thus, it is possible to keep the body cover on the front side of the seat low. [0026] The. saddle-riding type vehicle may include plural rear side frames that are connected to the rear ends of the sub-frames, respectively, to extend obliquely upward to the rear and are connected to one another. [0027] Consequently, the rear side portions of the sub-frames are reinforced by the plural rear side frames connected to one another. Thus, strength of the sub-frames increases. Therefore, it is possible to realise a reduction in a size or a, reduction in weight of the sub--frames. It is possible to keep the body cover on the front side of the seat low through the reduction in a size of the sub-frames. [0028] It is preferable that the sub-frames support the motor at least in one place tvear connecting portions to which the rear side frames are connected. [0025] Consequently, a part of the motor is supported by portions reinforced by the rear side frames in the sub-frames. Thus, it is possible to realize a reduction in a size or a reduction in weight of the sub-frames themselvee. Since it 7 is possible to reduce a size of the sub-frames, it is possible to keep the body cover on the front side of the seat low. [0030] it is preferable that the motor consists of an internal combustion engine having a crankcase and a cylinder that extends forward or obliquely upward to the front from the crankfcase, the cylinder is supported by the main frame, and the crankcase is supported by the sub-frames. [0031] Consequently, since the cylinder located on the front side of the motor is supported by the main frame and the crankcase located on the rear side of the motor is supported by the sub-frames, the motor is supported by the main frame and the sub-frames in a well-balanced state. Thus, it is possible to form the main frame and the sub-frames in appropriate lengths and form the main frame relatively short. Therefore, it is possible to realize a reduction in a size and a reduction in weight of the body frame while securing strength of the body frame. [0032] It is preferable that the cylinder extends obliquely upward to the front from the crankcase such that an axis of the cylinder extends obliquely in an upward direction, the sub-frames are bent convexly downward, and front side portions further on the front side than the bent portions in the sub-frames extend substantially parallel to the axis of the cylinder, [0033] Consequently, since the front side portions of the sub-frames extend along the cylinder of the internal combustion engine, it is possible to arrange the front side portions of the sub-frames in positions near the cylinder Thus, it is possible to reduce height of the sub-frames and keep the body cover covering the sub-frames low. [0034] It is preferable that the cylinder extends obliquely upward to the front from the crankcase such that the axis of the cylinder extends obliquely in the upward direction, the sub-frames are bent convexly downward, and the bent portions of the sub-frames are located above a boundary portion of the cylinder and the crankcase in the internal combustion engine. [0035] Consequently, since the sub-frames are arranged along the cylinder and the crankcase of the internal combustion engine, in setting the sub-frames and the internal combustion engine, efficient use of a space as realized. Since it is possible to arrange the sub-frames in positions near the combustion engine, it is possible to keep the body cover covering the sub-frames low, [0036] Another saddle-riding type vehicle according to the invention includes: a head pipe that supports a steering shaft to rotationally move freely; a body frame including a main frame that is connected to the head pipe and extends obliquely downward to the rear and a pair of left and right sub-frames that are connected to the main frame and extend obliquely downward to the rear; and a motor supported in positions of 9 [0040] still another saddle-riding type vehicle according to the invention is a saddle-riding type vehicle including; a head pipe that supports a steering shaft to rotationally move freely; a body frame that extends obliquely downward to the rear from the head pipe; and a motor sup-ported by the body frame in a suspended state. The body frame includes at least a pair of left and right side frames and the paddle-riding type vehicle includes' a real wheel; rear arms that support the rear wheel and extend substantially in a front to rear direction; left and right brackets fixed to the left and the right side frames, respectively; and a pivot shaft that pierces through both the brackets, both the rear arms, and the motor and attaches both the rear arms and the Motor to both the brackets in a state in which the left and the right brackets are interposed between the Left and the right rear arms and the motor, respectively. [0041] According to the saddle-riding type vehicle, the buckets fixed to the left and the right frames are interposed between the motor and the left and the right rear arms, respectively. Thus, it is possible to reduce an interval between the left and the right brackets compared with a case in which the brackets are provided on an outer side of the motor and the rear arms. Therefore, it is possible to reduce intervals on the left and the right of the side frames and realise a reduction in width of the vehicle. [0042] The body frame may include a main frame that is connected 11 to the head pipe and extends obliquely downward to the rear and a pair of left and right sub-frames that are connected to the main frame and extend obliquely downward to the rear. The side frames may consist of the sub-frames. [0043] Consequently, the motor functions as a reinforcing member to increase strength of the sub-frames. Thus, it as possible to realize a reduction in a size or a reduction in weight of the frames. [0044] It is preferable that a part of the motor is supported by the main frame. [0045] Consequently, since the motor functions as the reinforcing member, strength of the main frame is increased. Thus, it is possible to realise, a further reduction in a size or reduction in weight of the body frame. Advantages of the Invention [0046] As described above, according to the invention, since the motor is supported by the main frame and the left and the right sub-frames, it is possible to use the motor as the reinforcing member. Thus, it is possible to realize a reduction in a size and a reduction in weight of the body frame while maintaining strength of the body frame. [0047] If the motor is supported in positions of two places in the front and the rear of the left and the right sub-fraines, it is possible to reinforce the the places in the front and the rear of the sub-frames with the motor and realize a 12 reduction in a size and a reduction in weight while maintaining strength of the body frame [0048] If left and the right brackets fixed to a pair of left and right side frames, respectively, are interposed between the motor and the left and the right rear arms, respectively, and then the motor and the left and the right rear arms are- attached to the brackets together, it is possible to reduce an interval between the left and the right side frames and realize a reduction in width of the vehicle. Brief Description of the Drawings [0049] Fig. 1 is a schematic side view of a motorcycle according to an embodiment of the invention. Fig 2 is a perspective view of a motor cycle according to the embodiment of the invention. Fig, 3 is a sectional view along line A-A in Fig, 1. Fig. 4 is a sectional view along line B-B in Fig, 1. Description of Reference Numerals and Signs [0050] 10 Motorcycle 11 Body frame 12 Engine (Motor, Internal combustion engine) 12a Cylinder 12b Crankcase 15 Head pipe 19 Main frame 13 20 Sub-frames 26 Bear arms 29 Brackets 29 Pivot shaft Best Mode for carrying out the Invention [0051] An embodiment of the invention will be hereinafter explained on the basis of the drawings [0052] As shown in Fig. 1, a saddle-riding type vehicle according to the embodiment 15 a motorcycle 10 of a so-called Underbone type. The motorcycle 10 includes a body frame 11 forming a skeleton and an engine 12 supported by the body frame 11 in a suspended state. [0053] A head pipe 15 is provided at a front end of the body frame 11. A not-shown steering shaft is inserted into the head pipe is to rotate freely. A not-shown front fork is provided on a lower side of the steering shaft. A front wheel 18 is supported by the body frame 11 to be capable of moving rotationally via the front fork and the like. [0054} One main frame 19 is fixed to the head pipe 15. The main frame 19 extends obliquely downward to the rear from the head pipe 15. In order to secure sufficient strength, the main frame 19 is formed relatively thick and a section of the main frame 19 is formed in a hollow rectangular shape. In this embodiment, the main, frame 19 is constituted by assembling a 14 pair of left and right beam-shaped members . Specifically, the main frame 13 includes a pair of left and right beam-shaped members that extend obliquely downward to the rear and are bent 90 degrees at both top and bottom ends. The main frame 15 is constituted by joining bent portions of the left and the right beam-shaped members in a left to right direction. However, it goes without spying that a method of forming the hollow main frame 19 is not limited at all and other forming methods may be used. [0055] A cross-sectional area of the main frame 19 is different at a front end 19c and at a rear end 13b connected to the head pipe 15. The cross-sectional area of the main frame 19 is larger at the front end 19c than the rear end 19b and changes along a longitudinal direction of the main frame 19. Note that the cross-sectional area of the main frame 19 may chahge continuously along the longitudinal direction of the main frame 19 or may change stepwise. [0056] A gusset 27 is fixed to a lower side of a front half portion of the main frame 19. The gusset 27 is arranged to be laid over between the main frame 19 and the head pipe 15. [0057] A bracket 22 is fixed to a lower side of the rear end 19b of the main frame 19 A cylinder 12a of the engine 12 is attached to the bracket 22 via a bolt and a nut. In other words, the cylinder 12a of the engine 12 is supported by the main frame 19 via the bracket 22. 15 [0058] The engine 12 is a water-cooled engine. The engine 12 includes the cylinder 12a and a crankcase 12b. The cylinder 12a extends obliquely upward to the front from the crankcase 12b. The cylinder 12a includes a cylinder block, and a cylinder head attached to an upper side of the cylinder bloc}:. The cylinder 12a is supported in a posture with an axial direction of the cylinder l2a and a longitudinal direction of the main frame 19 substantially parallel to each other. [0059] A carburetor 13 is disposed behind the cylinder 12a. The carburetor 13 is arranged near a lower side of the rear end 19b of the main frame 19, that is, on an extension line to the rear of the main frame 19. An air cleaner 21 that purifies the outside air and supplies the outside air to the carnuretor 13 is disposed on a rear side of the carburetor 13. The air cleaner 21 is arranged in a position near the carburetor 13, that is, a position adjacent to the carburetor 13. The air cleaner 21 assumes substantially a rectangular parallelepiped shape. As shown in Fig. l, the air cleaner 21 is arranged obliquely such that an upper end side thereof is positioned further in the front of the vehicle than a lower end side thereof. [0060] A battery 34 is arranged behind and above the air cleaner 21. The battery 34 is located on a lower side of a seat 36 to be maintained by opening the seat 36. [0061] In this way, since the air cleaner 21 is arranged near 16 the rear of the carburetor 13, an air intake passage is made linear and simplified. Thus, it is possible to improve performance of the engine 12, The air cleaner 21 and the battery 34 are relatively large components. When the air cleaner 21 and the battery 34 are arranged in a vehicle width direction, a vehicle width tends to be large. However, in the motorcycle 10, since the air cleaner 21 and the battery 34 are arranged in a front to rear direction of the vehicle, it is possible to control the vehicle width and reduce width of the vehicle. Moreover, since the air cleaner 21 is arranged in a tilted posture, it is possible to effectively use a space on a lower side of the battery 34 as a part of a space for setting the air cleaner 21. Therefore, it is possible to control length in the front to rear direction of the vehicle and height of the vehicle while securing a capacity of the air cleaner 21. [0062] A fuel tank 35 13 disposed behind the battery 34 and below the seat 36. [0063] A radiator 24 that cools cooling water supplied to the engine 12 is arranged above the cylinder 12a of the engine 12 and below the main frame 19. A not-shown bracket 13 provided in the gusset 27. The radiator 24 is supported by the body frame 11 via the bracket. [0064] Incidentally, in the vehicle of the underbone type, that is, a vehicle in which the main frame 19 inclines obliquely downward at a relatively steep angle, there 15 a problem 17 described below concerning a space for setting the radiator 24. In the vehicle of the underbone type, when it is attempted to arrange the radiator 24 below the main frame 13 and above the cylinder head, a space for setting the radiator 24 is relatively limited. Thus, in the motorcycle 10, a lower edge 27a of the gusset 27 is bent to be recessed upward. In other words, the lower edge 27a of the gusset 27 is bent to escape upward. Consequently, the space for setting the radiator 24 increases to prevent contact of the gusset 27 and the radiator 24. In other words, since the lower edge 27a of the gusset 27 is bent upward, the gusset 27 and the radiator 24 are less likely to interfere with each other. It is possible to efficiently arrange the gusset 27 in a limited space. Since this makes it possible to arrange the gusset 27 with a suitable size in a suitable position., it is possible to improve strength of the main frame 19. [0065] As shown in Fig- 2, sub-frames 20 are fixed to both side portions 19a on the left and the right of the main frame 19. Specifically, a pair of sub-frames 20 are provided on the left and the right and front ends 20a of the respective sub-frames 20 are fixed near the center in the Longitudinal direction of the main frame 19. Most parts of the sub-frames 20 assume a round pape shape. A section of the sub-frames 20 is formed smaller than a section of the main frame 19, A shape of the front ends 20a of the sub-frames 20 is changed from the pipe shape to the planar shape toward a front side thereof Portions of the planar shape are joined to the side portion 19a of the main frame 19 by welding or the like in. a, state in which the portions are in surface contact with the side portion 19a. [0066] The sub-frames 20 have a bent structure. Specifically, as shown in Fig. 1, substantially the center in the longitudinal direction of the sub-frames 20 is bent to be projected downward. Bent portions 20b are located above a boundary portion of the crankcase 12b and the cylinder 12a of the engine 12. Front side portions 20c further on the front side than the bent portions 20b extend substantially parallel to an axial direction of the cylinder 12a of the engine 12 Rear side portions 20d farther on a real side than the bent portions 20b are inclined more gently than the front side portions 20c. [0067] Brackets 23 are fixed to rear side portions 20d (portions near the rear of the bent portions 20b) of the sub-frames 20. The crankcase 12b of the engine 12 is attached to the brackets 23 via a bolt and a nut. [0068] The rear side portions 20d of the sub-frames 20 extend to the rear of the engine 12. Brackets 28 are fixed to rear ends 20e of the rear side portions 20d of the sub-frames 20. Both the crankcase 12b of the engine 12 and rear arms 26 are supported by the brackets 28. [0069] Specifically, as shown in Fig. 1, the brackets 28 made of metal extending downward, respectively, are fixed to the 19 rear ends 20e of the pair of left and right sub-frames 20. A pivot shaft 25 is suspended between the brackets 28. As shown in Fig 3, a bolt head 29a is provided at one end of the pivot shaft 29 and a male thread portion 29b is formed at the other end. The male thread portion 29b is screwed in a nut 30. The crankcase 12b of the engine 12 and front end cylindrical portions 26a of the rear arms 2 6 are supportea by the pivot shaft 29 supported by the brackets 28. [0070] Specifically, as showm in Fig. 3, on the left side of the engine 12, the front end cylindrical portion 26a of the rear arm 2 6 on the left side is arranged between the bolt head 29a of the pivot shaft 29 and the bracket 28, The front end cylindrical portion 26a is supported by the pivot shaft 29 via a bush 38 with internal and external cylinders and is capable of rotationally moving around the pivot shaft 29 within a predetermined angle range. The bush 38 with internal and external cylinders includes an inner cylinder 38a and an outer cylinder 38c made of iron and an intermediate cylinder 38b made of rubber interposed between the inner cylinder 3Ba and the outer cylinder 38c. The pivot shaft 29 is inserted into the inner cylinder 38a and the outer cylinder 38c is pressed into the front end cylindrical portion 26a of the rear arm 26. Consequently, when the front end cylindrical portion 26a of the rear arm. 26 rotationally moves around the pivot shaft 29, the intermediate cylinder 38b made of rubber of the bush 38 20 with internal and external cylinders is elastic ally deformed to allow rotational movement of the rear arm 26 and regulate rotational movement of the rear arm 26 exceeding a predetermined range. [0071] The front end cylindrical portion 26a is also provided in the rear arm 26 on the right side of the engine 12. The front end cylindrical portion 2 6a is arranged between the bracket 28 on the right side and a washer 33 on the nut 30 side. The front end cylindrical portion 26a of the rear arm 26 on the right side is also supported to rotationally move freely by the pivot shaft 29 via the bush 38 with internal and external cylinders and rotationally moves in the predetermined angle range. [0072] Moreover, the crankcase 12b of the engine 12 is held between the pair of left and right brackets 28, 23. A through-hole 12c extending to the left and the right is formed in the crankcase 12b and the pivot shaft 29 is inserted through the through-hole 12c. With such a constitution, the crankcase 12b is supported by the pivot shaft 29. [0073] The crankcase 12b of the engine 12, the left and the right brackets 28, and the left and the right inner cylinders 38a are integrally combined by screwing the male thread portion 29b of the pivot shaft 29 in the nut 30. The inner cylinder 38a on. the right side is held between the bracket 28 on the right side and the mit 30 portion (accurately, the washer 33). 21 [0060] In this way, in the motorcycle 10, the engine 12 is fixed to be laid over between the main frame 19 and the sub-fraides 20. Thus, the engine 12 also functions as a reinforcing member for the body frame 11. Therefore, it is possible to realize a redaction in a size and a reduction rn weight of the body frame 11 while maintaining strength of the vehicle. [0081] As shown in Fig, 4, according to the motorcycle 10, it is possible to form the sub-frames 20 in a thin round pipe shape. Thus, it is possible to keep a center tunnel portion 37a of the leg shield 31 in front of the seat 36 low. In other wortis, as indicated by an alternate long and two short dashes line In Fig 4, when the sub-frames 20 ate formed of relatively thick square pipes in order to increase strength, since positions of upper surfaces of the square pipes are elevated, a position of the leg shield 37 is also elevated as indicated by an alternate long and two short dashes line in the figure, on the other hand, in. the motorcycle 10, since the sub-frames 20 are formed of a round pipe and thickness of the sub-frames 20 is reduced, it is possible to reduce height of the leg shield 37. [0082] According to the motorcycle 10, connhecting positions of the sub-frames 20 and the main frame 19, that is, positions of the front ends 20a of the sub-frames 20 are ahead of a supporting portion of the engine 12 in the main frame 19, that is, a position of the bracket 22. in this way, since the front 24 ends 20a of the sub-frames 20 are connected ahead of the supporting portion of the engine. 12 (aportion where the bucket 22 is disposed) in the main frame 19, a portion between the front end 19c of the main frame 19 and the supporting portion is reinforced by the sub-frames 20. Thus, it is possible to increase strength of the main frame 19, It is possible to effectively increase strength of the main frame 19 by contriving a connecting position of the sub-frames 20 according to a necessary strength distribution of the main frame 19. [0083] The main frame 19 is formed thicker at the front end 19c than the rear end 19b. Thus, on the front end. 19c side connected to the head pipe 15, it is possible to secure strength against bending moment sufficiently. On the other hand, it is possible to form the rear end 19b side thin. Since it is possible to form the rear end 19b side thin in this way, it is possible to keep the center tunnel portion. 37a of the leg shield 37 low. [0084] The cylinder 12a of the engine 12 is supported by the main frame 19 having large strength. Thus, it is possible to reduce length of the main frame 19 compared with a case in which the cylinder 12a of the engine 12 is supported by the sub-frames 20. Therefore, it is possible to realize a reduction in weight of the body frame 11 while securing necessary strength, [0065] The cylinder 12a of the engine 12 is supported by, in particular, a portion near the rear end of the main frasae 19, 25 that is, the rear end 19b. Thus, it is possible to reduce length of the main frame 19 and realize a further reduction in weight of the body frame 11. [0086] The front side, portions 20c of the sub-frames 20 extend substantially in parallel to the axial direction of the cylinder 12a of the engine 12. Thus, it is possible to effectively bring the front side portions 20c of the sub-frames 20 close to the cylinder 12a. As a result, it is possible to reduce height of the sub-frames 20 Therefore, it is possible to keep the center tunnel portion 37a of the leg shield 37 low. [0087] The cylinder 12a of the engine 12 extends obliquely upward from the crankcase 12b. The engine 12 is formed in a shape binding upward as a whole. The bent portions 20b of the sub-frames 20 are located above the boundary portion of the cylinder 12a of the engine 12 and the crankcase 12. Thus, the sub-frames 20 are arranged along the bent shape of the engine 12. Therefore, since it is possible to arrange the sub-frames 20 in positions near the engine 12, it is possible to keep the center tunnel portion 37a of the leg shield 37 lower. [0088] According to the motorcycle 10, middle portions of the sub-frames 20 are bent to be recessed downward. The engine 12 is supported near the bent portions 20b of the sub-frames 20. Thus, it is possible to reinforce strength in the bent portions 20b of the sub-frames 20 with the engine 12. Moreover, it is possible to keep the center tunnel portion 37a of the 26 leg shield 37 lower. [0089] According to the motorcycle 10, the seat rails 31 extending obliquely upward to the rear is fixed to the rear side portions 20d further on the rear side than the bent portions 20b of the sub-frames 20. Consequently, the sub-frames 20 are reinforced. Therefore, it is possible to reduce a diameter of the sub-frames 20 while securing strength of the entire body frame 11 and keep the center tunnel portion 37a of the leg shield 37 lower. [0090] According to the motorcycle 10, the portions further on the rear side than the bent portions 20b of the sub-frames 20 extend to the rear of the engine 12. Both the engine 12 and the rear arms 26 ate supported by the rear ends 20e of the sub-frames 20 via the brackets 28. Consequently, it is possible to simplify a supporting structure for the engine 12 and the like and reduce a size of the brackets 28. [0091] The front ends 31a arid 32a of the seat rails 31 and the back stays 32 extending obliquely upward to the rear are fixed to the rear ends 20e of the sub-frames 20. The seat rails 31 and the back stays 32 are connected to each other on the rear end sides thereof. Consequently, it is possible to reduce a diameter of the sub-frames 20 while securing strength of the body frame 11 and keep the center tunnel portion 37a of the leg snield 37 lower. [0032] The engine 12 as supported by portions near the 27 connecting portions of the seat rails 31 and the back stays 32 in the sub-frames 20. Consequently, since the engine 12 is supported by portions having high strength in the sub-frames 20, it is possible to reduce thickness of the sub-frames 20 while securing strength of the body frame 11. [0093] The engine 12 is supported by the main frame 19 via the bracket 22 and supported by portions of two places separated to the front and the rear of the respective sub-frames 20 via the brackets 23 and the brackets 28. Thus, the engine 12 is supported by the main frame 19 and the sub-frames 20 in a well-balanced stata. The function of the engine 12 as a reinforcing member is improved to make it possible to obtain larger strength compared with a case in which the engine 12 is supported by one portion of the sub-frames 20. [0094] The pair of sub-frames 20 are provided on the left and the right, respectively. The pair of brackets 26 provided in the left and the right sub-frames 20 are interposed between the rear arms 26 supporting the rear wheel 25 and the engine 12 (see Fig. 3) Thus, it is possible to control an increase in an interval between the left and the right sub-frames 20 and reduce a width of the vehicle while mainataining strength of the body frame 11. [0095] Incidentally, when it is assumed that the brackets 28 are disposed on an outer side of the rear arms 26 and the inner cylinders 38a of the bush 38 with internal and external 28 cylinders are directly in contact with the crankcass 12lp of the engine 12, it is likely that the inner cylinders 38a made of iron cut into the crankcase 12b made of aluminum because of tightening of the nut 30 at the time of assembly. In that case, in order to prevent the inner cylinders 38a from cutting into the crankcase 12b, it is necessary to dispose washers between the inner cylinders 38a and the crarikcase 12b. However, in the motorcycle 10, the tabular brackets 23 made of iron are interposed between the inner cylinders 39a made of iron and the crankcase 12b made of aluminum. Thus, when the nut 30 is tightened, the inner cylinders 38a never cut into the crankease 12b side, Therefora, since it is unnecessary to provide washers, it is possible to redues the numbar of components , [0096] Note that, in the motorcycle 10 according to the embodiment, the pair of sub-frames 20 formed symmetrically are provided as the pair of left and right sub-frames. However, the pair of Left end right sub-frames only have to he provided on the left and the right of the vehicle and do not always have to be formed symmetrically. [0097] The motorcycle 10 according to the embodment includes the engine 12, which serves as an internal combustion engine, as the "motor". However, it goes without saying that the motor is not limited to the engine 12 and may be other motors such as an electric motor. The saddle-riding type vehicle according to the invention is not limited to the motorcycle 29 10. Industrial Applicability [0098] As described above, the invention is useful for the saddle-riding type vehicle such as a motorcycle. 30 Claims [1] A saddle-riding type vehicle comprising: a head pipe that supports a steering shaft to rotationally move freely; a body frame including a main frame that is connected to the head pipe and extends obliquely downward to a rear and a pair of left and right sub-frames that are connected to the main frame and extend obliquely downward to the rear, and a motor supported by the main frame and the respective sub-frames in a suspended state. [2] A saddle-riding type vehicle according to claim 1, wherein a connecting portion of the main frame and the sub-frames is located ahead of a portion supporting the motor in the main frame. [3] A saddle-riding type vehicle according to claim. 1 or 2, wherein. the head pipe is connected to a front end side of the main frame, and a cross sectional area of the main frame changes along a longitudinal direction of the main frame such that the front end side is larger than a rear end side. [4] A saddle-riding type vehicle according to any one of claims 1 to 3, wherein the main frame supports the motor at the rear end of the main, frame. [5] A saddle-riding type vehicle according to any one of 31 claims 1 to 4, wherein the sub-frames are bent convexly downward and support the motor at least in one place near bent portions [6] A saddle-riding type vehicle according to any one of claims 1 to 5, wherein the sub-frames are bent convexly downward and support the motor at least in one place further on a rear side than the bent portions. [7] A saddle-riding type vehicle according to any one of claims 1 to 6, wherein. the saddle-riding type vehicle includes: a rear wheel; and rear anus that support the rear wheel and extend substantially in a front to rear direction, the sub-frame is bent convexly downward, and both a part of the motor and the rear arms are supported at the rear ends of the sub-frames. [8] A saddle-riding type vehicle according to any one of claims 1 to 7, wherein the sub-frames are bent convexly downward, and the saddle-riding type vehicle includes rear side frames that are connected to a portion further on the rear side than the bent portions of the sub-frames and extend obliquely upward to the rear. [9] A saddle-riding type vehicle according to any one of claims 1 to 7, wherein the saddle-riding type vehicle include plural rear side 32 frames that are connected to the rear ends of the sub-frames, respectively, to extend obliquely upward to the rear and are connected to one another. [10] A saddle-ridinq type vehicle according to claim 8 or 9, wherein the sub-frames support the motor at least in one place near connecting portions to which the rear side frames are connected. [11] A saddle-riding type vehicle according to any one of claims 1 to 10, wherein the motor consists of an internal combustion engine having a crankcase and a cylinder that extends forward or obliquely upward to the front from the crankcase, the cylinder is supported by the main frame, and the crankcase is supported by the sub-frames [12] A saddle-riding type vehicle according to claim 11, wherein the cylinder extends obliquely upward to the front from the crankcase such that an axis of the cylinder extends obliquely in an upward direction, the sub-frames are bent convexly downward, and front side portions further on the front side than the bent portions in the sub-frames extend substantially parallel to the axis of the cylinder. [13] A saddle-riding type vehicle according to claim 11, wherein 33 the, cylinder extends obliquely upward to the front from the crankcase such that the axis of the cylinder extends obliquely in the upward direction, the sub-frames are bent convexly downward, and the bent portions of the sub-frames are located above a boundary portion of the cylinder and the crankcase in the internal combustion engine. [14] A saddle-riding type vehicle comprising: a head pipe that supports a steering shaft to rotatlonally move freely; a body frame including a main frame that is connected to the head pipe and extends obliquely downward to the rear and a pair of left and right sub-frames that are connected to the main frame and extend obliquely downward to the rear; and a motor supported in positions of two places separated in a front to rear direction in the respective sub-frames in a suspended state. [15] A saddle-riding type vehicle according to claim 14, wherein the motor consists of an internal combustion engine including a crankcase and a cylinder that extends forward or obliquely upward to the front from the crankcsse, the cylinder 13 supported by the main frame, and the cranktase is supported by the sub-frames [16] A saddle-riding type vehicle comprising. 34 a head pipe that supports a steering shaft to rotationally move freely; a body frame that extends obliquely downward to the rear from the head pipe; and a motor supported by the body frame in a suspended state, wherein the body frame includes at least a pair of left and right side frames, and the saddle-riding type vehicle includes: a rear wheel; rear arms that support the rear wheel and extend substantially in a front to rear direction; left and right brackets fixed to the left and the right side frames, respectively, and a pivot shaft that pierces through both the brackets, both the rear arms, and the motor and attaches both the rear arms and the motor to both the brackets in a state in which the left and the right brackets are interposed between the left and the right rear arms and the motor, respectively. [17] A saddle-riding type vehicle according to claim 16, wherein the body frame includes a main frame that is connected to the head pipe and extends obliquely downward to the rear and a pair of left and right sub-frames that are connected to the main frame and extend obliquely downward to the rear, and the side frames consist of the sub-frames. 35 36 [18] A saddle-riding type vehicle according to claim 17, wherein a part of tha motor is supported by the main frame. A motorcycle (10) includes a head pipe (15) that supports a steering shaft to rotationally move freely, a body frame (11) connected to the head pipe (15), and an engine (12) supported by the body frame (11) in a suspended state. The body frame (11) includes a main frame (19) that extends obliquely downward to the rear from the head pipe (15) and a pair of left and right sub-frames (20) that extend obliquely downward to the rear from the main frame (19) . The engine (12) includes a crankcase (l2b) and a cylinder (12a) that extends obliquely upward to the front from the crankcase (l2b) . The cylinder (12a) is supported by a rear end (19b) of the main frame (19) . The crankcase (l2o) is supported by portions in two places sewpatated to the front, and the rear in the respective sub-frames (20).

Full Text

DESCRIPTION
Saddle-riding Type Vehicle
Technical Field
[0001] The invention relates to a saddle-riding type vehicle
such as a motorcycle.
Background Art
[0002] Conventionally, there is known a saddle-ridinq type
vehicle including a head pipe that supports a steering handle
to be capable of moving rotationally, a frame that extends
obliquely downward to the rear from the headpipe, and an engine
supported by the frame in a suspended state. As the
saddle-riding type vehicle of this type, for example,
motorcycles disclosed in Patent Documents 1 to 3 described
below are known,
[0003] The motorcycle disclosed, in the Patent Document 1
includes a head pipe and a pair of left atid right maim frames
that extend obliquely downward to the rear from the head pipe.
Brackets are coupled to rear portioms of the main frames, An
engine is supported by the left and the right main frames and
brackets in a suspended state. The motorcycle also includes
rear swing arms that support a rear wheel The rear swing arms
are supported by the brackets via. a pivot shaft to move up and
1

down freely,
[0004] Patent Document 1. JP-A-08-067285
Patent Document 2: JP~A-05-330474
Patent Document 3: JP-A-03-330475
Disclosure of the Invention
Problems that the Invention 15 to solve
[0005] Incidentally, in such a saddle-riding type vehicle, it
is desired to reduce weight of a body frame or reduce width
of the vehicle while maintaining strength of the body frame.
For improvement of convenience in getting on and off the vehicle,
it is also desired to keep a portion ahead of a seat low.
[0006] However, in the conventional saddle-riding type vehicle,
the engine is supported by the pair of left and right main frames
and brackets in an upper part and a rear part of a crankcase
of the engine. Consequently, the main frames and the brackets
are required to have rigidity that is large to some extent.
Therefore, in order to secure rigidity of the main frames and
the brackets, it is necessary to increase thickness of the main
frames and the brackets. However, when thickness of the main
frames and the like is increased, it is difficult to reduce
weight of the body frame
[0007] In the conventional saddle-ridinq type vehicle, both.
the engine and the rear swing arms ate held between the pair
of left and right brackets. Consequently, an interval between
2

the left and the right brackets is increased and the main frame
sticks out in the Left to right direction. Therefore, it is
difficult to reduce width of the vehicle (a reduction in width
in a vehicle Width direction).
[0008] Thus, it is an object of the invention to realize a
reduction in weight of a body frame while maintaining strength
of the body frame in a saddle-riding type vehicle. It is
another object of the invention to realize a reduction in width
of the vehicle while maintaining strength of the body frame.
It is still another object of the invention to keep a portion
ahead of a seat of the vehicle low.
Means for salving the Problems
[0009] A saddle-riding type vehicle according to the invention
includes: a head pipe that supports a steering shaft to
rotationally move freely: a body frame including a main frame
that is connected to the bead pipe and extends obliquely-
downward to the rear and a pair of left and right sub-frames
that are connected to the main frame and extend obliquely
downward to the rear; and a motor supported by the main frame
and the respective sub-frames in a suspended state.
[0010] According to the saddle-riding type vehicle, the motor
is supported by the main frame and both the sub-frames, whereby
the motor is arranged to be laid over the main frame and both
the left and the right sub-frames- As a result, since the main
frame and the sub-frames are reinforced by the motor, it is
3

possible to keep strength of the main frame itself or the
sub-frames themselves low because of reinforcement by the motor.
Therefore, it is possible to resalize a seduction in a size or
a reduction in weight of the body frame while maintaining
strength of the body frame.
[0011] It is preferable that a connecting portion of the main
frame ancl the sub-frames is located ahead of a portion
supporting the motor in the main frame.
[0012] Consequently, a portion between a front end portion of
the main frame and a portion supporting the motor 15 reinforced
by the sub-frames. Thus, strength of the main frame is improved.
Note that a necessary strength distribution of the main frame
differs for each vehicle. However, it is possible to make a
strength distribution of the main frame suitable or optimum
by adjusting a connecting position of the sub-frames to the
main frame appropriately.
[0013] It is preferable that the head pipe is connected to a
front end side of the main frame and a cross sectional area
of the main frame changes along a longitudinal direction of
the main frame such that the front end side is larger than a
rear end side.
[0014] Note that the change in the cross sectional area of the
main frame may be continuous or stepwise along the longitudinal
direction of the main frame. A form of the change in the cross
sectional area is not specifically lumited.
4

[0015] Consequently, the main frame is formed relatively thick
on the front end side connected to the head pipe. Thus, it
is possible to secure larger strength of the main frame against
bending moment. On the other hand, since the rear end of the
main frame is formed relatively thin, when a body cover on a
front side of the seat is arranged above the rear end of the
main frame, it is possible to keep the body cover low.
[0016] It is preferable that the main frame supports the motor
at the rear end of the main frame.
[0017] Consequently, it is possible to reduce length of the
main frame.
[0018] It is possible that the sub-frames are bent convexly
downward and support the motor at least in one place near bent
portions.
[0019] Consequently, the motor functions as a reinforcing
member to increase strength of the bent portions of the
sub-frames. Since the strength of the sub-frames increases.
it is possible to realize a reduction in a size or a reduction
in weight of the sub-frames. Since it is possible to reduce
a size of the sub-frames, it is possible to keep the body cover
on the front side of the seat low.
[0020] It is preferable that the sub-frames are bent convexly
downward and support the motor at least in one place further
on a rear side than the bent portions.
[0021] Consequently, the motor functions as a reinforcing
5

member and strength in portions further on the rear side of
the bent portions in the sub-frames increases. Since the
strength of the sub-frames increases, it is possible to realise
a reduction in size and a reduction in weight of the sub-frames .
Since it is possible to reduce a size of the sub-frames, it
is possible to keep the body covet on the front side of the
seat low.
[0022] It is preferable that the saddle-riding type vehicle
includes: a rear wheel; and rear arms that support the rear
wheel and extend substantially in a front to rear direction,
the sub-crams iS beat convexly downward, and both a part of
the motor and the rear arms are supported at the rear ends of
the sub-frames.
[0023] Consequently, since a part of the motor 15 supported
together with the rear arms, it is possible to simplify a
supporting structure for the motor and the rear arms. Since
the motor and the rear anus are supported together, in using
brackets for support, it is possible to reduce a size of the
brackets compared with a case in which the motor and the rear
arms are supported separately. Since it is possible to reduce
a size of the brackets in this way, it is possible to increase
strength of the entire body frame.
[0024] It is preferable that the sub-frames are bent convexly
downward and the saddle-riding type vehicle further includes
rear side frames that are connected to a portion further on
6

the rear side than the bent portions of the sub-frames and
extand obliquely upward to the rear.
[0025] Consequently, the rear side portions of the sub-frames
are reinforced by the reer side frames, it is possible to
reduce a size of the sub-frames because the sub-frames are
rein forced. Thus, it is possible to keep the body cover on
the front side of the seat low.
[0026] The. saddle-riding type vehicle may include plural rear
side frames that are connected to the rear ends of the
sub-frames, respectively, to extend obliquely upward to the
rear and are connected to one another.
[0027] Consequently, the rear side portions of the sub-frames
are reinforced by the plural rear side frames connected to one
another. Thus, strength of the sub-frames increases.
Therefore, it is possible to realise a reduction in a size or
a, reduction in weight of the sub--frames. It is possible to
keep the body cover on the front side of the seat low through
the reduction in a size of the sub-frames.
[0028] It is preferable that the sub-frames support the motor
at least in one place tvear connecting portions to which the
rear side frames are connected.
[0025] Consequently, a part of the motor is supported by
portions reinforced by the rear side frames in the sub-frames.
Thus, it is possible to realize a reduction in a size or a
reduction in weight of the sub-frames themselvee. Since it
7

is possible to reduce a size of the sub-frames, it is possible
to keep the body cover on the front side of the seat low.
[0030] it is preferable that the motor consists of an internal
combustion engine having a crankcase and a cylinder that
extends forward or obliquely upward to the front from the
crankfcase, the cylinder is supported by the main frame, and
the crankcase is supported by the sub-frames.
[0031] Consequently, since the cylinder located on the front
side of the motor is supported by the main frame and the
crankcase located on the rear side of the motor is supported
by the sub-frames, the motor is supported by the main frame
and the sub-frames in a well-balanced state. Thus, it is
possible to form the main frame and the sub-frames in
appropriate lengths and form the main frame relatively short.
Therefore, it is possible to realize a reduction in a size and
a reduction in weight of the body frame while securing strength
of the body frame.
[0032] It is preferable that the cylinder extends obliquely
upward to the front from the crankcase such that an axis of
the cylinder extends obliquely in an upward direction, the
sub-frames are bent convexly downward, and front side portions
further on the front side than the bent portions in the
sub-frames extend substantially parallel to the axis of the
cylinder,
[0033] Consequently, since the front side portions of the

sub-frames extend along the cylinder of the internal combustion
engine, it is possible to arrange the front side portions of
the sub-frames in positions near the cylinder Thus, it is
possible to reduce height of the sub-frames and keep the body
cover covering the sub-frames low.
[0034] It is preferable that the cylinder extends obliquely
upward to the front from the crankcase such that the axis of
the cylinder extends obliquely in the upward direction, the
sub-frames are bent convexly downward, and the bent portions
of the sub-frames are located above a boundary portion of the
cylinder and the crankcase in the internal combustion engine.
[0035] Consequently, since the sub-frames are arranged along
the cylinder and the crankcase of the internal combustion
engine, in setting the sub-frames and the internal combustion
engine, efficient use of a space as realized. Since it is
possible to arrange the sub-frames in positions near the
combustion engine, it is possible to keep the body cover
covering the sub-frames low,
[0036] Another saddle-riding type vehicle according to the
invention includes: a head pipe that supports a steering shaft
to rotationally move freely; a body frame including a main frame
that is connected to the head pipe and extends obliquely
downward to the rear and a pair of left and right sub-frames
that are connected to the main frame and extend obliquely
downward to the rear; and a motor supported in positions of
9

[0040] still another saddle-riding type vehicle according to
the invention is a saddle-riding type vehicle including; a head
pipe that supports a steering shaft to rotationally move
freely; a body frame that extends obliquely downward to the
rear from the head pipe; and a motor sup-ported by the body frame
in a suspended state. The body frame includes at least a pair
of left and right side frames and the paddle-riding type vehicle
includes' a real wheel; rear arms that support the rear wheel
and extend substantially in a front to rear direction; left
and right brackets fixed to the left and the right side frames,
respectively; and a pivot shaft that pierces through both the
brackets, both the rear arms, and the motor and attaches both
the rear arms and the Motor to both the brackets in a state
in which the left and the right brackets are interposed between
the Left and the right rear arms and the motor, respectively.
[0041] According to the saddle-riding type vehicle, the
buckets fixed to the left and the right frames are interposed
between the motor and the left and the right rear arms,
respectively. Thus, it is possible to reduce an interval
between the left and the right brackets compared with a case
in which the brackets are provided on an outer side of the motor
and the rear arms. Therefore, it is possible to reduce
intervals on the left and the right of the side frames and
realise a reduction in width of the vehicle.
[0042] The body frame may include a main frame that is connected
11

to the head pipe and extends obliquely downward to the rear
and a pair of left and right sub-frames that are connected to
the main frame and extend obliquely downward to the rear. The
side frames may consist of the sub-frames.
[0043] Consequently, the motor functions as a reinforcing
member to increase strength of the sub-frames. Thus, it as
possible to realize a reduction in a size or a reduction in
weight of the frames.
[0044] It is preferable that a part of the motor is supported
by the main frame.
[0045] Consequently, since the motor functions as the
reinforcing member, strength of the main frame is increased.
Thus, it is possible to realise, a further reduction in a size
or reduction in weight of the body frame.
Advantages of the Invention
[0046] As described above, according to the invention, since
the motor is supported by the main frame and the left and the
right sub-frames, it is possible to use the motor as the
reinforcing member. Thus, it is possible to realize a
reduction in a size and a reduction in weight of the body frame
while maintaining strength of the body frame.
[0047] If the motor is supported in positions of two places
in the front and the rear of the left and the right sub-fraines,
it is possible to reinforce the the places in the front and
the rear of the sub-frames with the motor and realize a
12

reduction in a size and a reduction in weight while maintaining
strength of the body frame
[0048] If left and the right brackets fixed to a pair of left
and right side frames, respectively, are interposed between
the motor and the left and the right rear arms, respectively,
and then the motor and the left and the right rear arms are-
attached to the brackets together, it is possible to reduce
an interval between the left and the right side frames and
realize a reduction in width of the vehicle.
Brief Description of the Drawings
[0049] Fig. 1 is a schematic side view of a motorcycle according
to an embodiment of the invention.
Fig 2 is a perspective view of a motor cycle according
to the embodiment of the invention.
Fig, 3 is a sectional view along line A-A in Fig, 1.
Fig. 4 is a sectional view along line B-B in Fig, 1.
Description of Reference Numerals and Signs
[0050] 10 Motorcycle
11 Body frame
12 Engine (Motor, Internal combustion engine)
12a Cylinder
12b Crankcase
15 Head pipe
19 Main frame
13

20 Sub-frames
26 Bear arms
29 Brackets
29 Pivot shaft
Best Mode for carrying out the Invention
[0051] An embodiment of the invention will be hereinafter
explained on the basis of the drawings
[0052] As shown in Fig. 1, a saddle-riding type vehicle
according to the embodiment 15 a motorcycle 10 of a so-called
Underbone type. The motorcycle 10 includes a body frame 11
forming a skeleton and an engine 12 supported by the body frame
11 in a suspended state.
[0053] A head pipe 15 is provided at a front end of the body
frame 11. A not-shown steering shaft is inserted into the head
pipe is to rotate freely. A not-shown front fork is provided
on a lower side of the steering shaft. A front wheel 18 is
supported by the body frame 11 to be capable of moving
rotationally via the front fork and the like.
[0054} One main frame 19 is fixed to the head pipe 15. The
main frame 19 extends obliquely downward to the rear from the
head pipe 15. In order to secure sufficient strength, the main
frame 19 is formed relatively thick and a section of the main
frame 19 is formed in a hollow rectangular shape. In this
embodiment, the main, frame 19 is constituted by assembling a
14

pair of left and right beam-shaped members . Specifically, the
main frame 13 includes a pair of left and right beam-shaped
members that extend obliquely downward to the rear and are bent
90 degrees at both top and bottom ends. The main frame 15 is
constituted by joining bent portions of the left and the right
beam-shaped members in a left to right direction. However,
it goes without spying that a method of forming the hollow main
frame 19 is not limited at all and other forming methods may
be used.
[0055] A cross-sectional area of the main frame 19 is different
at a front end 19c and at a rear end 13b connected to the head
pipe 15. The cross-sectional area of the main frame 19 is
larger at the front end 19c than the rear end 19b and changes
along a longitudinal direction of the main frame 19. Note that
the cross-sectional area of the main frame 19 may chahge
continuously along the longitudinal direction of the main frame
19 or may change stepwise.
[0056] A gusset 27 is fixed to a lower side of a front half
portion of the main frame 19. The gusset 27 is arranged to
be laid over between the main frame 19 and the head pipe 15.
[0057] A bracket 22 is fixed to a lower side of the rear end
19b of the main frame 19 A cylinder 12a of the engine 12 is
attached to the bracket 22 via a bolt and a nut. In other words,
the cylinder 12a of the engine 12 is supported by the main frame
19 via the bracket 22.
15

[0058] The engine 12 is a water-cooled engine. The engine 12
includes the cylinder 12a and a crankcase 12b. The cylinder
12a extends obliquely upward to the front from the crankcase
12b. The cylinder 12a includes a cylinder block, and a cylinder
head attached to an upper side of the cylinder bloc}:. The
cylinder 12a is supported in a posture with an axial direction
of the cylinder l2a and a longitudinal direction of the main
frame 19 substantially parallel to each other.
[0059] A carburetor 13 is disposed behind the cylinder 12a.
The carburetor 13 is arranged near a lower side of the rear
end 19b of the main frame 19, that is, on an extension line
to the rear of the main frame 19. An air cleaner 21 that
purifies the outside air and supplies the outside air to the
carnuretor 13 is disposed on a rear side of the carburetor 13.
The air cleaner 21 is arranged in a position near the carburetor
13, that is, a position adjacent to the carburetor 13. The
air cleaner 21 assumes substantially a rectangular
parallelepiped shape. As shown in Fig. l, the air cleaner 21
is arranged obliquely such that an upper end side thereof is
positioned further in the front of the vehicle than a lower
end side thereof.
[0060] A battery 34 is arranged behind and above the air cleaner
21. The battery 34 is located on a lower side of a seat 36
to be maintained by opening the seat 36.
[0061] In this way, since the air cleaner 21 is arranged near
16

the rear of the carburetor 13, an air intake passage is made
linear and simplified. Thus, it is possible to improve
performance of the engine 12, The air cleaner 21 and the
battery 34 are relatively large components. When the air
cleaner 21 and the battery 34 are arranged in a vehicle width
direction, a vehicle width tends to be large. However, in the
motorcycle 10, since the air cleaner 21 and the battery 34 are
arranged in a front to rear direction of the vehicle, it is
possible to control the vehicle width and reduce width of the
vehicle. Moreover, since the air cleaner 21 is arranged in
a tilted posture, it is possible to effectively use a space
on a lower side of the battery 34 as a part of a space for setting
the air cleaner 21. Therefore, it is possible to control length
in the front to rear direction of the vehicle and height of
the vehicle while securing a capacity of the air cleaner 21.
[0062] A fuel tank 35 13 disposed behind the battery 34 and
below the seat 36.
[0063] A radiator 24 that cools cooling water supplied to the
engine 12 is arranged above the cylinder 12a of the engine 12
and below the main frame 19. A not-shown bracket 13 provided
in the gusset 27. The radiator 24 is supported by the body
frame 11 via the bracket.
[0064] Incidentally, in the vehicle of the underbone type, that
is, a vehicle in which the main frame 19 inclines obliquely
downward at a relatively steep angle, there 15 a problem
17

described below concerning a space for setting the radiator
24. In the vehicle of the underbone type, when it is attempted
to arrange the radiator 24 below the main frame 13 and above
the cylinder head, a space for setting the radiator 24 is
relatively limited. Thus, in the motorcycle 10, a lower edge
27a of the gusset 27 is bent to be recessed upward. In other
words, the lower edge 27a of the gusset 27 is bent to escape
upward. Consequently, the space for setting the radiator 24
increases to prevent contact of the gusset 27 and the radiator
24. In other words, since the lower edge 27a of the gusset
27 is bent upward, the gusset 27 and the radiator 24 are less
likely to interfere with each other. It is possible to
efficiently arrange the gusset 27 in a limited space. Since
this makes it possible to arrange the gusset 27 with a suitable
size in a suitable position., it is possible to improve strength
of the main frame 19.
[0065] As shown in Fig- 2, sub-frames 20 are fixed to both side
portions 19a on the left and the right of the main frame 19.
Specifically, a pair of sub-frames 20 are provided on the left
and the right and front ends 20a of the respective sub-frames
20 are fixed near the center in the Longitudinal direction of
the main frame 19. Most parts of the sub-frames 20 assume a
round pape shape. A section of the sub-frames 20 is formed
smaller than a section of the main frame 19, A shape of the
front ends 20a of the sub-frames 20 is changed from the pipe

shape to the planar shape toward a front side thereof Portions
of the planar shape are joined to the side portion 19a of the
main frame 19 by welding or the like in. a, state in which the
portions are in surface contact with the side portion 19a.
[0066] The sub-frames 20 have a bent structure. Specifically,
as shown in Fig. 1, substantially the center in the longitudinal
direction of the sub-frames 20 is bent to be projected downward.
Bent portions 20b are located above a boundary portion of the
crankcase 12b and the cylinder 12a of the engine 12. Front
side portions 20c further on the front side than the bent
portions 20b extend substantially parallel to an axial
direction of the cylinder 12a of the engine 12 Rear side
portions 20d farther on a real side than the bent portions 20b
are inclined more gently than the front side portions 20c.
[0067] Brackets 23 are fixed to rear side portions 20d (portions
near the rear of the bent portions 20b) of the sub-frames 20.
The crankcase 12b of the engine 12 is attached to the brackets
23 via a bolt and a nut.
[0068] The rear side portions 20d of the sub-frames 20 extend
to the rear of the engine 12. Brackets 28 are fixed to rear
ends 20e of the rear side portions 20d of the sub-frames 20.
Both the crankcase 12b of the engine 12 and rear arms 26 are
supported by the brackets 28.
[0069] Specifically, as shown in Fig. 1, the brackets 28 made
of metal extending downward, respectively, are fixed to the
19

rear ends 20e of the pair of left and right sub-frames 20. A
pivot shaft 25 is suspended between the brackets 28. As shown
in Fig 3, a bolt head 29a is provided at one end of the pivot
shaft 29 and a male thread portion 29b is formed at the other
end. The male thread portion 29b is screwed in a nut 30. The
crankcase 12b of the engine 12 and front end cylindrical
portions 26a of the rear arms 2 6 are supportea by the pivot
shaft 29 supported by the brackets 28.
[0070] Specifically, as showm in Fig. 3, on the left side of
the engine 12, the front end cylindrical portion 26a of the
rear arm 2 6 on the left side is arranged between the bolt head
29a of the pivot shaft 29 and the bracket 28, The front end
cylindrical portion 26a is supported by the pivot shaft 29 via
a bush 38 with internal and external cylinders and is capable
of rotationally moving around the pivot shaft 29 within a
predetermined angle range. The bush 38 with internal and
external cylinders includes an inner cylinder 38a and an outer
cylinder 38c made of iron and an intermediate cylinder 38b made
of rubber interposed between the inner cylinder 3Ba and the
outer cylinder 38c. The pivot shaft 29 is inserted into the
inner cylinder 38a and the outer cylinder 38c is pressed into
the front end cylindrical portion 26a of the rear arm 26.
Consequently, when the front end cylindrical portion 26a of
the rear arm. 26 rotationally moves around the pivot shaft 29,
the intermediate cylinder 38b made of rubber of the bush 38
20

with internal and external cylinders is elastic ally deformed
to allow rotational movement of the rear arm 26 and regulate
rotational movement of the rear arm 26 exceeding a
predetermined range.
[0071] The front end cylindrical portion 26a is also provided
in the rear arm 26 on the right side of the engine 12. The
front end cylindrical portion 2 6a is arranged between the
bracket 28 on the right side and a washer 33 on the nut 30 side.
The front end cylindrical portion 26a of the rear arm 26 on
the right side is also supported to rotationally move freely
by the pivot shaft 29 via the bush 38 with internal and external
cylinders and rotationally moves in the predetermined angle
range.
[0072] Moreover, the crankcase 12b of the engine 12 is held
between the pair of left and right brackets 28, 23. A
through-hole 12c extending to the left and the right is formed
in the crankcase 12b and the pivot shaft 29 is inserted through
the through-hole 12c. With such a constitution, the crankcase
12b is supported by the pivot shaft 29.
[0073] The crankcase 12b of the engine 12, the left and the
right brackets 28, and the left and the right inner cylinders
38a are integrally combined by screwing the male thread portion
29b of the pivot shaft 29 in the nut 30. The inner cylinder
38a on. the right side is held between the bracket 28 on the
right side and the mit 30 portion (accurately, the washer 33).
21

[0060] In this way, in the motorcycle 10, the engine 12 is fixed
to be laid over between the main frame 19 and the sub-fraides
20. Thus, the engine 12 also functions as a reinforcing member
for the body frame 11. Therefore, it is possible to realize
a redaction in a size and a reduction rn weight of the body
frame 11 while maintaining strength of the vehicle.
[0081] As shown in Fig, 4, according to the motorcycle 10, it
is possible to form the sub-frames 20 in a thin round pipe shape.
Thus, it is possible to keep a center tunnel portion 37a of
the leg shield 31 in front of the seat 36 low. In other wortis,
as indicated by an alternate long and two short dashes line
In Fig 4, when the sub-frames 20 ate formed of relatively thick
square pipes in order to increase strength, since positions
of upper surfaces of the square pipes are elevated, a position
of the leg shield 37 is also elevated as indicated by an
alternate long and two short dashes line in the figure, on
the other hand, in. the motorcycle 10, since the sub-frames 20
are formed of a round pipe and thickness of the sub-frames 20
is reduced, it is possible to reduce height of the leg shield
37.
[0082] According to the motorcycle 10, connhecting positions
of the sub-frames 20 and the main frame 19, that is, positions
of the front ends 20a of the sub-frames 20 are ahead of a
supporting portion of the engine 12 in the main frame 19, that
is, a position of the bracket 22. in this way, since the front
24

ends 20a of the sub-frames 20 are connected ahead of the
supporting portion of the engine. 12 (aportion where the bucket
22 is disposed) in the main frame 19, a portion between the
front end 19c of the main frame 19 and the supporting portion
is reinforced by the sub-frames 20. Thus, it is possible to
increase strength of the main frame 19, It is possible to
effectively increase strength of the main frame 19 by
contriving a connecting position of the sub-frames 20 according
to a necessary strength distribution of the main frame 19.
[0083] The main frame 19 is formed thicker at the front end
19c than the rear end 19b. Thus, on the front end. 19c side
connected to the head pipe 15, it is possible to secure strength
against bending moment sufficiently. On the other hand, it
is possible to form the rear end 19b side thin. Since it is
possible to form the rear end 19b side thin in this way, it
is possible to keep the center tunnel portion. 37a of the leg
shield 37 low.
[0084] The cylinder 12a of the engine 12 is supported by the
main frame 19 having large strength. Thus, it is possible to
reduce length of the main frame 19 compared with a case in which
the cylinder 12a of the engine 12 is supported by the sub-frames
20. Therefore, it is possible to realize a reduction in weight
of the body frame 11 while securing necessary strength,
[0065] The cylinder 12a of the engine 12 is supported by, in
particular, a portion near the rear end of the main frasae 19,
25

that is, the rear end 19b. Thus, it is possible to reduce length
of the main frame 19 and realize a further reduction in weight
of the body frame 11.
[0086] The front side, portions 20c of the sub-frames 20 extend
substantially in parallel to the axial direction of the
cylinder 12a of the engine 12. Thus, it is possible to
effectively bring the front side portions 20c of the sub-frames
20 close to the cylinder 12a. As a result, it is possible to
reduce height of the sub-frames 20 Therefore, it is possible
to keep the center tunnel portion 37a of the leg shield 37 low.
[0087] The cylinder 12a of the engine 12 extends obliquely
upward from the crankcase 12b. The engine 12 is formed in a
shape binding upward as a whole. The bent portions 20b of the
sub-frames 20 are located above the boundary portion of the
cylinder 12a of the engine 12 and the crankcase 12. Thus, the
sub-frames 20 are arranged along the bent shape of the engine
12. Therefore, since it is possible to arrange the sub-frames
20 in positions near the engine 12, it is possible to keep the
center tunnel portion 37a of the leg shield 37 lower.
[0088] According to the motorcycle 10, middle portions of the
sub-frames 20 are bent to be recessed downward. The engine
12 is supported near the bent portions 20b of the sub-frames
20. Thus, it is possible to reinforce strength in the bent
portions 20b of the sub-frames 20 with the engine 12. Moreover,
it is possible to keep the center tunnel portion 37a of the
26

leg shield 37 lower.
[0089] According to the motorcycle 10, the seat rails 31
extending obliquely upward to the rear is fixed to the rear
side portions 20d further on the rear side than the bent
portions 20b of the sub-frames 20. Consequently, the
sub-frames 20 are reinforced. Therefore, it is possible to
reduce a diameter of the sub-frames 20 while securing strength
of the entire body frame 11 and keep the center tunnel portion
37a of the leg shield 37 lower.
[0090] According to the motorcycle 10, the portions further
on the rear side than the bent portions 20b of the sub-frames
20 extend to the rear of the engine 12. Both the engine 12
and the rear arms 26 ate supported by the rear ends 20e of the
sub-frames 20 via the brackets 28. Consequently, it is
possible to simplify a supporting structure for the engine 12
and the like and reduce a size of the brackets 28.
[0091] The front ends 31a arid 32a of the seat rails 31 and the
back stays 32 extending obliquely upward to the rear are fixed
to the rear ends 20e of the sub-frames 20. The seat rails 31
and the back stays 32 are connected to each other on the rear
end sides thereof. Consequently, it is possible to reduce a
diameter of the sub-frames 20 while securing strength of the
body frame 11 and keep the center tunnel portion 37a of the
leg snield 37 lower.
[0032] The engine 12 as supported by portions near the
27

connecting portions of the seat rails 31 and the back stays
32 in the sub-frames 20. Consequently, since the engine 12
is supported by portions having high strength in the sub-frames
20, it is possible to reduce thickness of the sub-frames 20
while securing strength of the body frame 11.
[0093] The engine 12 is supported by the main frame 19 via the
bracket 22 and supported by portions of two places separated
to the front and the rear of the respective sub-frames 20 via
the brackets 23 and the brackets 28. Thus, the engine 12 is
supported by the main frame 19 and the sub-frames 20 in a
well-balanced stata. The function of the engine 12 as a
reinforcing member is improved to make it possible to obtain
larger strength compared with a case in which the engine 12
is supported by one portion of the sub-frames 20.
[0094] The pair of sub-frames 20 are provided on the left and
the right, respectively. The pair of brackets 26 provided in
the left and the right sub-frames 20 are interposed between
the rear arms 26 supporting the rear wheel 25 and the engine
12 (see Fig. 3) Thus, it is possible to control an increase
in an interval between the left and the right sub-frames 20
and reduce a width of the vehicle while mainataining strength
of the body frame 11.
[0095] Incidentally, when it is assumed that the brackets 28
are disposed on an outer side of the rear arms 26 and the inner
cylinders 38a of the bush 38 with internal and external
28

cylinders are directly in contact with the crankcass 12lp of
the engine 12, it is likely that the inner cylinders 38a made
of iron cut into the crankcase 12b made of aluminum because
of tightening of the nut 30 at the time of assembly. In that
case, in order to prevent the inner cylinders 38a from cutting
into the crankcase 12b, it is necessary to dispose washers
between the inner cylinders 38a and the crarikcase 12b. However,
in the motorcycle 10, the tabular brackets 23 made of iron are
interposed between the inner cylinders 39a made of iron and
the crankcase 12b made of aluminum. Thus, when the nut 30 is
tightened, the inner cylinders 38a never cut into the crankease
12b side, Therefora, since it is unnecessary to provide
washers, it is possible to redues the numbar of components ,
[0096] Note that, in the motorcycle 10 according to the
embodiment, the pair of sub-frames 20 formed symmetrically are
provided as the pair of left and right sub-frames. However,
the pair of Left end right sub-frames only have to he provided
on the left and the right of the vehicle and do not always have
to be formed symmetrically.
[0097] The motorcycle 10 according to the embodment includes
the engine 12, which serves as an internal combustion engine,
as the "motor". However, it goes without saying that the motor
is not limited to the engine 12 and may be other motors such
as an electric motor. The saddle-riding type vehicle
according to the invention is not limited to the motorcycle
29

10.
Industrial Applicability
[0098] As described above, the invention is useful for the
saddle-riding type vehicle such as a motorcycle.
30

Claims
[1] A saddle-riding type vehicle comprising:
a head pipe that supports a steering shaft to
rotationally move freely;
a body frame including a main frame that is connected
to the head pipe and extends obliquely downward to a rear and
a pair of left and right sub-frames that are connected to the
main frame and extend obliquely downward to the rear, and
a motor supported by the main frame and the respective
sub-frames in a suspended state.
[2] A saddle-riding type vehicle according to claim 1,
wherein a connecting portion of the main frame and the
sub-frames is located ahead of a portion supporting the motor
in the main frame.
[3] A saddle-riding type vehicle according to claim. 1 or 2,
wherein.
the head pipe is connected to a front end side of the
main frame, and
a cross sectional area of the main frame changes along
a longitudinal direction of the main frame such that the front
end side is larger than a rear end side.
[4] A saddle-riding type vehicle according to any one of
claims 1 to 3, wherein the main frame supports the motor at
the rear end of the main, frame.
[5] A saddle-riding type vehicle according to any one of
31

claims 1 to 4, wherein the sub-frames are bent convexly downward
and support the motor at least in one place near bent portions
[6] A saddle-riding type vehicle according to any one of
claims 1 to 5, wherein the sub-frames are bent convexly downward
and support the motor at least in one place further on a rear
side than the bent portions.
[7] A saddle-riding type vehicle according to any one of
claims 1 to 6, wherein.
the saddle-riding type vehicle includes:
a rear wheel; and
rear anus that support the rear wheel and extend
substantially in a front to rear direction,
the sub-frame is bent convexly downward, and
both a part of the motor and the rear arms are supported
at the rear ends of the sub-frames.
[8] A saddle-riding type vehicle according to any one of
claims 1 to 7, wherein
the sub-frames are bent convexly downward, and
the saddle-riding type vehicle includes rear side frames
that are connected to a portion further on the rear side than
the bent portions of the sub-frames and extend obliquely upward
to the rear.
[9] A saddle-riding type vehicle according to any one of
claims 1 to 7, wherein
the saddle-riding type vehicle include plural rear side
32

frames that are connected to the rear ends of the sub-frames,
respectively, to extend obliquely upward to the rear and are
connected to one another.
[10] A saddle-ridinq type vehicle according to claim 8 or 9,
wherein the sub-frames support the motor at least in one place
near connecting portions to which the rear side frames are
connected.
[11] A saddle-riding type vehicle according to any one of
claims 1 to 10, wherein
the motor consists of an internal combustion engine
having a crankcase and a cylinder that extends forward or
obliquely upward to the front from the crankcase,
the cylinder is supported by the main frame, and
the crankcase is supported by the sub-frames
[12] A saddle-riding type vehicle according to claim 11,
wherein
the cylinder extends obliquely upward to the front from
the crankcase such that an axis of the cylinder extends
obliquely in an upward direction,
the sub-frames are bent convexly downward, and
front side portions further on the front side than the
bent portions in the sub-frames extend substantially parallel
to the axis of the cylinder.
[13] A saddle-riding type vehicle according to claim 11,
wherein
33

the, cylinder extends obliquely upward to the front from
the crankcase such that the axis of the cylinder extends
obliquely in the upward direction,
the sub-frames are bent convexly downward, and
the bent portions of the sub-frames are located above
a boundary portion of the cylinder and the crankcase in the
internal combustion engine.
[14] A saddle-riding type vehicle comprising:
a head pipe that supports a steering shaft to
rotatlonally move freely;
a body frame including a main frame that is connected
to the head pipe and extends obliquely downward to the rear
and a pair of left and right sub-frames that are connected to
the main frame and extend obliquely downward to the rear; and
a motor supported in positions of two places separated
in a front to rear direction in the respective sub-frames in
a suspended state.
[15] A saddle-riding type vehicle according to claim 14,
wherein
the motor consists of an internal combustion engine
including a crankcase and a cylinder that extends forward or
obliquely upward to the front from the crankcsse,
the cylinder 13 supported by the main frame, and
the cranktase is supported by the sub-frames
[16] A saddle-riding type vehicle comprising.
34

a head pipe that supports a steering shaft to
rotationally move freely;
a body frame that extends obliquely downward to the rear
from the head pipe; and
a motor supported by the body frame in a suspended state,
wherein the body frame includes at least a pair of left
and right side frames, and
the saddle-riding type vehicle includes:
a rear wheel;
rear arms that support the rear wheel and extend
substantially in a front to rear direction;
left and right brackets fixed to the left and the right
side frames, respectively, and
a pivot shaft that pierces through both the brackets,
both the rear arms, and the motor and attaches both the rear
arms and the motor to both the brackets in a state in which
the left and the right brackets are interposed between the left
and the right rear arms and the motor, respectively.
[17] A saddle-riding type vehicle according to claim 16,
wherein
the body frame includes a main frame that is connected
to the head pipe and extends obliquely downward to the rear
and a pair of left and right sub-frames that are connected to
the main frame and extend obliquely downward to the rear, and
the side frames consist of the sub-frames.
35

36
[18] A saddle-riding type vehicle according to claim 17,
wherein a part of tha motor is supported by the main frame.

A motorcycle (10) includes a head pipe (15) that supports
a steering shaft to rotationally move freely, a body frame (11)
connected to the head pipe (15), and an engine (12) supported
by the body frame (11) in a suspended state. The body frame
(11) includes a main frame (19) that extends obliquely downward
to the rear from the head pipe (15) and a pair of left and right
sub-frames (20) that extend obliquely downward to the rear from
the main frame (19) . The engine (12) includes a crankcase (l2b)
and a cylinder (12a) that extends obliquely upward to the front
from the crankcase (l2b) . The cylinder (12a) is supported by
a rear end (19b) of the main frame (19) . The crankcase (l2o)
is supported by portions in two places sewpatated to the front,
and the rear in the respective sub-frames (20).

SADDLE-RIDING TYPE VEHICLE

Documents:

Inventors:

PCT Conventions: