JP2015013507A - Motor cycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor cycle in which contact between a shock absorber and an obstacle on a road surface is prevented while the shock absorber is placed below a driving source such as an engine.SOLUTION: In a motor cycle, a vehicle body frame (1) includes a lower frame (6) extending below a driving source such as an engine and a shock absorber (51) of a rear suspension device (50) is placed below the drive source. The shock absorber (51) is arranged along a substantially fore-and-aft direction, and a lower end of the shock absorber (51) is disposed so as to be positioned above a lower surface of the lower frame (6). Preferably, the motor cycle includes a pair of left and right lower frames (6) and the shock absorber (51) is disposed between the lower frames (6).

Description

  The present invention relates to a motorcycle in which a shock absorber of a rear suspension device is disposed below a drive source such as an engine.

  FIG. 9 shows an example of the motorcycle having the above configuration (Patent Document 1). The swing arm 202 that supports the rear wheel 201 is elastically supported by the vehicle body frame 205 by the rear suspension device 203. The rear suspension device 203 includes a shock absorber 207 disposed on the lower side of the engine 206, and a link link member structure 210 that connects the rear end portion of the shock absorber 207 to the swing arm 202 and the vehicle body frame 205.

U.S. Pat. No. 7,178,621, FIG.

  In the motorcycle disclosed in Patent Document 1, since the shock absorber is disposed on the lower side of the engine, the shock absorber and the obstacle on the road surface easily come into contact with each other.

  An object of the present invention is to provide a motorcycle capable of preventing contact between a shock absorber and an obstacle on a road surface while disposing the shock absorber under a drive source such as an engine.

  In order to solve the above problems, the present invention relates to a motorcycle in which a vehicle body frame has a lower frame extending below a drive source, and a shock absorber of a rear suspension device is disposed below the drive source. The shock absorber is disposed so as to be substantially along the front-rear direction, and the lower end of the shock absorber is disposed above the lower surface of the lower frame. The drive source includes an electric motor in addition to the engine.

  According to the present invention, (1) the shock absorber disposed below the drive source of the engine or the like is disposed such that the lower end thereof is located above the lower surface of the lower frame. Prevents contact with obstacles on the road surface, making it easier to protect the shock absorber from the outside.

(2) Since the shock absorber is arranged below the drive source, a large space for arranging an intake device such as an intake box can be secured behind the drive source.

  The present invention can include the following configuration in addition to the configuration of the motorcycle.

(A) A pair of left and right lower frames is provided, and the shock absorber is disposed between the left and right lower frames.

  According to the above configuration (a), the left and right lower frames can protect the shock absorber from obstacles located outward in the vehicle width direction, and the protection effect can be enhanced.

(B) The front end portion of the shock absorber is supported by a support portion provided above the upper surface of the lower frame so as to be swingable in the vertical direction.

  According to the configuration (b), the shock absorber can be easily attached from the side of the vehicle body.

(C) A reserve tank connected to the cylinder portion of the shock absorber via a communication pipe is disposed in front of the shock absorber.

  According to the said structure (c), a reserve tank can be arrange | positioned compactly using the space ahead of a shock absorber.

(D) In a motorcycle including a pair of left and right lower frames and a communication pipe, a cross member that connects the pair of left and right lower frames is formed with a recess that allows the communication pipe to pass in the front-rear direction.

  According to the said structure (d), it can pipe compactly, without extending a communicating pipe upward or downward.

(E) A protective plate that covers the lower side of the shock absorber is provided.

  According to the above configuration (e), it is possible to protect the shock absorber from pebbles and pebbles that are splashed from below during traveling.

(F) The lower frame is provided with a drive source mounting portion at a position ahead of the front end support portion of the shock absorber.

  According to the configuration (f), the drive source itself such as the engine can be used as a cross member of the body frame, and the rigidity of the body frame can be increased.

(G) The shock absorber is arranged so that the axial center line is raised rearward, and the downwardly convex arcuate locus while the rear end of the shock absorber moves between the most compressed position and the most extended position. Move along.

  According to the said structure (g), a shock absorber can be arrange | positioned close to the lower surface of a drive source, and compactization can be achieved.

  In short, according to the present invention, there is provided a motorcycle that prevents contact between a shock absorber and an obstacle on a road surface while disposing the shock absorber below a drive source such as an engine.

1 is a left side view of a motorcycle including a rear suspension device according to the present invention. Fig. 2 is a left side view of a rear suspension device for the motorcycle shown in Fig. 1. Fig. 2 is a bottom view of the shock absorber of the motorcycle of Fig. 1. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3. FIG. 3 is a perspective view of the link mechanism of the rear suspension device of FIG. It is a rear view of the link mechanism of FIG. FIG. 3 is a left side view of the rear suspension device of FIG. 2 when the shock absorber is fully extended. FIG. 3 is a left side view of the rear suspension device of FIG. 2 when the shock absorber is fully compressed. FIG. 6 is a side view of a conventional motorcycle.

  An embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, the traveling direction of the vehicle will be described as “front” of the vehicle and each component, and the left-right direction viewed from the rider will be described as “left-right direction” of the vehicle and each component. In FIGS. 1 and 3, a protection plate 49 (see FIGS. 2 and 4) that covers the lower and front sides of a crankcase 38 to be described later is removed.

[Overall configuration of vehicle]
FIG. 1 is a left side view of the entire motorcycle. A vehicle body frame 1 includes a head pipe 2, a pair of left and right main frames 3 extending substantially rearward and downward from the head pipe 2, and a head pipe 2 extending substantially downward. The book has a down frame 5 and a pair of left and right lower frames 6 connected to the lower end bifurcated portion of the down frame. The rear end portion of the main frame 3 extends downward as a swing arm bracket portion 3a. The lower frame 6 extends downward from the lower end portion of the down frame 5 and curves backward, and extends rearward in a substantially horizontal state. The lower end portion of the lower frame 6 is coupled to the lower end portion of the swing arm bracket portion 3a. Has been. The lower frame 6 is located below the lower end of the swing arm bracket portion 3a.

  A seat rail 10 extending substantially rearward is connected to a substantially middle portion in the front-rear direction of the main frame 3, and a rear frame 11 extending rearward and upward is connected to an upper end portion of the swinger bracket portion 3a. The rear end portion is coupled to the rear end portion of the seat rail 10.

  The head pipe 2 supports a pair of left and right front forks 15 via a steering shaft (not shown) and upper and lower brackets 13, and a front wheel 17 is connected to a lower end portion of the front fork 15 via a front axle 16. Is supported rotatably.

  A fuel tank 18 and a seat 19 are provided on the main frame 3 and the seat rail 10, an exhaust muffler 20 is provided on the lower side of the rear frame 11, and a front fender 21 is provided on the front fork. Yes.

  The engine 30 is mounted in the vehicle body frame 1, and includes a pair of left and right lower mounting portions 31 provided on the lower frame 6, a pair of left and right upper mounting portions 32 provided on the main frame 3, and a swing arm bracket portion. It is supported on the vehicle body frame 1 by a pivot shaft portion 3a of 3a and a pair of left and right front mounting portions 34 provided at the lower end portion of the down frame 5. The engine 30 is connected to the left and right frame portions of the body frame 1 by being supported by the body frame 1 in the pair of left and right lower mounting portions 31, the upper mounting portion 32, and the front mounting portion 34. It also has a function as A radiator 35 is attached to the down frame 5, and an intake air cleaner box 36 is disposed in the rear portion of the main frame 3.

  The swing arm 40 for supporting the rear wheels is rotatably supported by the pivot shaft portion 33 of the swing arm bracket portion 3a and extends rearward. The rear arm of the swing arm 40 is connected to the rear end via the rear axle 41. The wheel 42 is rotatably supported. A drive chain 45 is wound around a driven sprocket 43 provided on the rear wheel 42 and an output sprocket 44 disposed on the left side surface of the crankcase 38 of the engine 30. Then, the rear wheel 42 is driven. The output sprocket 44 and the driven sprocket 43 are arranged in a region 33 in which a space between the main frame 3 and the link mechanism 52 extends in a direction perpendicular to the vehicle width direction. Specifically, the output sprocket 44 and the driven sprocket 43 are disposed between the left main frame 3 and the link mechanism 52 as viewed from the front or the rear.

  The swing arm 40 is elastically supported on the vehicle body frame 1 by the rear suspension device 50. The rear suspension device 50 includes a shock absorber 51 disposed on the lower side of the crankcase 38 of the engine 30, a link mechanism 52 disposed on the rear side of the swing arm bracket portion 3 a of the main frame 3, and the front side of the crankcase 38. And a reserve tank 53 disposed in the tank.

[Chain guide mechanism]
FIG. 2 is a left side view of the rear suspension device 50 and the periphery thereof. The rear end of the left swing arm bracket portion 3a is disposed at a position higher than the upper surface of the swing arm 40 at the rear end portion in the vehicle width direction inner surface. A toothed upper chain guide roller 46 and a toothed lower chain guide roller 47 disposed below the lower surface of the swing arm 40 are rotatably provided. Furthermore, chain guide plates 48a and 48b for guiding the drive chain 45 are provided on the upper and lower surfaces of the left arm portion of the swing arm 40, respectively.

  As shown in FIG. 5, the swing arm bracket portion 3 a is formed with an attachment portion 46 a for attaching the shaft portion of the chain guide roller 46. The mounting portion 46a is recessed inward in the vehicle width direction from the outer surface in the vehicle width direction of the swing arm bracket 3a, and a nut 46b for fixing the shaft portion of the chain guide roller 46 is accommodated in the recessed portion. Has been. Thereby, the fastening member for the chain guide roller (the nut 46b and the like) suppresses the protruding amount of the main frame 3 outward in the vehicle width direction.

  The tension side portion (upper portion) of the drive chain 45 extends rearward from the upper end of the front output sprocket 44 while being in sliding contact with the upper surface of the upper chain guide plate 48a of the swing arm 40, and the left swing arm bracket portion 3a. A space surrounded by the inner surface in the vehicle width direction, the upper chain guide plate 48a, the left side surface of the link mechanism 52, and the upper chain guide roller 46 passes rearwardly.

  The loose side portion (lower portion) of the drive chain 45 includes a lower surface of the lower chain guide plate 48b, an inner surface in the vehicle width direction of the left swing arm bracket portion 3a, a lower chain guide roller 47, a shock absorber 51, And extends rearward along the lower surface of the lower chain guide plate 48b.

[Rear suspension device 50]
In FIG. 2, the crankcase 38 of the engine 30 has a rear lower surface located above the front and rear lower surfaces, and specifically, tilts upward so that it gradually becomes higher rearward. More specifically, the crankcase 38 integrally includes a first-half crank chamber portion 38a that houses a crankshaft and a second-half transmission chamber portion 38b that houses a gear-type transmission. Further, it is formed at a position higher than the lower surface of the crank chamber 38a by a predetermined width or more in the vertical direction. Specifically, the lower end portion of the crank chamber portion 38a is attached to the engine lower attachment portion 31 formed on the upper surface of the lower frame 6, and the lower surface of the transmission chamber portion 38b is connected to the crank chamber portion 38a. As it goes backwards from the back, it inclines back upward so that it becomes higher. Thereby, in a side view, a space in which the shock absorber 51 can be accommodated in a substantially horizontal posture is secured at least between the lower surface of the lower frame 6 and the lower surface of the transmission chamber portion 38b.

(Shock absorber 51)
The shock absorber 51 is arranged in the lower space of the transmission chamber portion 38b of the crankcase 38 so as to be slightly rearwardly inclined and substantially along the front-rear direction, and the lower end of the shock absorber 51 is at the lower frame 6 It extends rearward substantially parallel to the lower frame 6 at a position above the lower surface. In other words, the lower edge of the shock absorber 51 extending in the front-rear direction among the projection surfaces of the shock absorber 51 in the vehicle side view is the lower frame 6 extending in the front-rear direction among the projection surfaces of the lower frame 6. It is located above the lower edge.

  The shock absorber 51 is a coil-over type having a first-half cylinder portion 51a, a rod portion 51b that protrudes rearward and rearwardly from the cylinder portion 51a, and a coil spring 51c that is contracted between spring seats at the front and rear ends. It is. Oil and gas are injected into the cylinder portion 51a, and the rod portion 51b is covered with a cylindrical cover 51d. The rod part 51b can protrude rearward from the swing arm bracket part 3a together with the cover 51d, and the cover 51d is fitted to the outer peripheral surface of the cylinder part 51a so as to be slidable in the axial direction.

  A clevis (attached portion) 51e is formed at the front end portion of the cylinder portion 51a, and a flexible gas communication pipe 54 is connected to the cylinder portion 51a. The communication pipe 54 extends forward between the left and right lower frames 6, and the clevis 51 e extends in the left-right direction to the support portion 57 disposed in the vicinity of the rear side of the engine lower mounting portion 31 in a side view. It is rotatably supported via a support shaft 58 extending in the direction.

  The axis and lower end of the support shaft 58 are located above the upper surface of the lower frame 6, and the upper half of the shock absorber 51 is located above the upper surface of the lower frame 6. Furthermore, the lower end of the shock absorber 51 is located above the lower surface of the lower frame 6 as described above. In this embodiment, in a state where the rear end portion of the swing arm 40 swings upward, the shock absorber 51 and its periphery are relatively close to the road surface. Even in such a case, the lower frame 6 The shock absorber 51 is configured not to protrude downward from the lower surface.

  FIG. 3 is a bottom view of the shock absorber 51 and the crankcase 38, and the reserve tank 53 of the shock absorber 51 is formed in a cylindrical shape and is disposed in a saddle-like manner along the lower end bifurcated portion of the down tube 5. And is supported on the crankcase 38 by a holding band. Further, the shock absorber 51 is disposed at the center in the vehicle width direction so that the axial center line C1 is along the vehicle width center line.

  A lower end portion of the reserve tank 53 is connected to a front end portion of a communication pipe 54 for gas circulation. The left and right lower frames 6 are joined by a cross member 62 at an intermediate portion in the front-rear direction, and the gas flow communication pipe 54 passes through a recess 62 a formed on the lower surface of the left end portion of the cross member 62, The lower frame 6 extends forward along the inner surface in the vehicle width direction.

  The recess 62a formed in the cross member 62 that couples the left and right lower frames 6 is recessed upward and extends in the front-rear direction. On the other hand, the shock absorber 51 has a portion to which the communication pipe 54 is connected facing downward. Are arranged. As described above, the communication pipe 54 extends forward through the recess 62a formed in the left end portion of the cross member 62 located below the clevis 51e. As a result, the communication pipe 54 can extend forward between the pair of left and right lower frames 6 below the cross member 62, and its lower surface can be positioned above the lower surfaces of the pair of left and right lower frames 6.

  4 is a cross-sectional view (rear view) taken along the line IV-IV in FIG. 3, and the cross member 62 that joins the left and right lower frames 6 has L-shaped attachment surfaces 62b at the left and right ends. Each mounting surface 62b is in contact with the upper surface and the inner surface in the vehicle width direction of each lower frame 6, and is fixed to each lower frame 6 by welding. The pair of left and right engine lower mounting portions 31 and the pair of left and right shock absorber support portions 57 are integrally formed with the cross member 62 on the upper surface of the same cross member 62. The engine lower attachment portion 31 protrudes upward from the upper surfaces of the left and right ends of the cross member 62 and supports the lower end attachment portion 30 a of the engine 30 at a position higher than the upper surface of the lower frame 6. The support portion 57 of the shock absorber 51 is disposed at a substantially central portion in the vehicle width direction of the cross member 62 with a constant interval left and right, and protrudes upward from the upper surface of the cross member 62. A front end clevis 51e of the shock absorber 51 is rotatably supported by a support shaft 58 at a position above the upper surface.

  The resin protective plate 49 is attached to the lower surface of the lower frame 6 to cover the shock absorber 51, the communication pipe 54, and the crankcase 38 from below.

  The front end portion of the protection plate 49 is curved upward along the front end curved portion of the lower frame 6, and covers the reserve tank 53 (FIGS. 1 and 3) from the front. The protective plate 49 is formed with holes 49b of various shapes and sizes for weight reduction and air circulation, and a gas injection tool or the like is provided at a position corresponding to the gas injection port of the reserve tank 53. An insertion hole for insertion is formed.

(Link mechanism 52)
In FIG. 2, the link mechanism 52 includes a first link member 71 that connects the rear end portion of the shock absorber 51 and the swing arm 40, and a second link member 72 that connects the first link member 71 and the main frame 3. And have. In the present embodiment, the second link member 72 is disposed above the first link member 71. The first link member 71 includes a first connecting portion (shock side connecting portion) 81 at the lower end that is one end portion of the first link member 71, a second connecting portion (arm side connecting portion) 82 at the upper front end, And a third connecting portion (second link side connecting portion) 83 at the upper end, which is the other end portion of the first link member 71. The second link member 72 includes a lower fourth connecting portion (first link side connecting portion) 90 that is one end of the second link member 72 and a fifth upper end that is the other end of the second link member 72. And a connecting portion (frame side connecting portion) 91.

  The first connecting portion 81 of the first link member 71 is rotatably connected to the rear end portion of the rod portion 51 b of the shock absorber 51, and the second connecting portion 82 is the pivot shaft portion 33 of the swing arm 40. The third connecting portion 83 is rotatably connected to the fourth connecting portion 90 of the second link member 72. As described above, the fourth connecting portion 90 of the second link member 72 is rotatably connected to the third connecting portion 83 of the first link member 71, and the fifth connecting portion 91 is a swing arm. The bracket portion 3a is rotatably connected to the link support portion 3b at the upper end of the bracket portion 3a. In addition, in a present Example, the connection structure in each connection part is comprised through the pin, respectively, and it is comprised so that relative connection is possible between connection objects.

  FIG. 5 is a perspective view of the link mechanism 52, and the first connecting portion 81 is formed in a bifurcated shape that branches to the left and right, and between the bifurcated portions at a position below the lower surface of the swing arm 40. The rear end portion of the rod portion 51b of the shock absorber 51 is inserted and is rotatably connected. The first link member 71 is formed widely in the vehicle width direction and extends forward and upward from the first connecting portion 81. The second connecting portion 82 is rotatably connected to a support portion 40 a formed near the upper end of the swing arm 40 via a connecting pin 86. The connecting pin 86 penetrates the second connecting portion 82 in the vehicle width direction and is fixed to the left and right arm portions of the swing arm 40 by nuts 86b. As a result, the left and right arm portions serve as cross members. The left and right arm portions of the swing arm 40 are also connected by a connecting body 88.

  The first link member 71 passes through the front opening recess of the connection body 88 upward and upward, and the third connection portion 83 is located above the upper surface of the swing arm 40 and has step portions at the left and right ends. It is formed narrowly through. That is, the third connecting portion 83 is formed to have a narrower width in the vehicle width direction than the first and second connecting portions 81 and 82 by the width in the vehicle width direction of the stepped portions at the left and right end portions.

  The fifth connecting portion 91 of the second link member 72 is rotatably connected to the support portion 3b of the left and right swing arm bracket portions 3a via a connecting shaft 89 at a position above the upper chain guide roller 46. Has been. The connecting shaft 89 penetrates the boss-like fifth connecting portion 91 in the vehicle width direction and is connected to the left and right swing arm bracket portions 3a, thereby also serving as a cross member of the vehicle body frame 1. . The connecting shaft 89 that supports the fifth connecting portion 91 is detachably fastened to the mounting portion 3 b of the main frame 3 by a nut 89 a that protrudes outward in the vehicle width direction of the main frame 3.

  FIG. 6 is a rear view of the link mechanism 52, and the width in the vehicle width direction of the fifth connecting portion 91 of the second link member 72 substantially corresponds to the distance between the inner surfaces in the vehicle width direction of the left and right swing arm bracket portions 3a. It is formed to the dimension to be. An intermediate portion between the fourth and fifth connecting portions 90 and 91 of the second link member 72 is formed in a trapezoidal shape so that the width in the vehicle width direction becomes narrower as it goes rearward and downward. In addition, the trapezoidal portion is formed with a thin thickness for weight reduction. The fourth connecting portion 90 of the second link member 72 is formed in a bifurcated left and right shape, and the third connecting portion 83 of the first link member 71 is fitted into the bifurcated fourth connecting portion 90. It is.

  As described above, the intermediate portion in the vertical direction of the second link member 72 is formed in a trapezoidal shape whose width becomes narrower rearward and downward, and the width of the third connecting portion 83 in the vehicle width direction is narrowed. Thus, a space is provided between the left swing arm bracket portion 3a and the link mechanism 52 so that the drive chain 45 can be passed with a margin.

  In FIG. 6, assuming that the vertical plane including the axial center line C1 of the shock absorber 51 is a virtual symmetry plane, the connecting portions 81, 82, 83 (90), 91 of the link mechanism 52 are They are formed to extend in the left-right (vehicle width) direction symmetrically. Furthermore, each connection part 81, 82, 83 (90), 91 is connected and supported rotatably at both ends in the vehicle width direction.

  7 and 8 are side views of the rear suspension device 50 when the shock absorber 51 is fully extended and compressed, and the cover 51d and the spring 51c are omitted. As shown in FIG. 8, the rod part 51b of the shock absorber 51 at the time of the most compression is housed in the vehicle body frame 1 except for the rear end part in a side view, and is extended from the state shown in FIG. , Projecting rearward from the swing arm bracket portion 3a.

  In FIG. 8, when the shock absorber 51 is most compressed, the second connecting portion (arm-side connecting portion) 82 of the first link member 71 overlaps the swing arm bracket portion 3a in the vehicle width direction in a side view. .

  In the present embodiment, the distance between the axis O5 of the pivot shaft 33 and the axis O1 of the first connecting portion 81 is such that the axis O5 of the pivot shaft 33 and the axis of the second connecting portion 82 are the same. It is set to be larger than the distance to O2. Further, the distance between the axis O2 of the second connecting portion 82 and the axis O1 of the first connecting portion 81 is such that the axis O2 of the second connecting portion 82 and the axis O3 of the third connecting portion 83 are. It is set larger than the distance between. As a result, the amount of movement of the shock absorber 51 can be made larger than the amount of movement of the swing arm 40, and the shock reduction characteristics can be suitably set. At the time of expansion, the first connecting portion 81 is disposed behind the second connecting portion 82, and the third connecting portion 83 is disposed above the second connecting portion 82. As a result, a force acts in the direction of pushing the first connecting portion 81 forward during compression, and the amount of movement of the first connecting portion 81 in the vertical direction can be reduced and the amount of movement in the front-rear direction can be increased.

  On the lower surface of the swing arm 40, a recess 40b is formed in which a part of the first connecting portion 81 of the first link member 71 is fitted when the shock absorber 51 is extended most. As a result, a nut or the like fastened to the end of the first connecting portion 81 is exposed to the outside in the vehicle width direction when the shock absorber 51 is fully extended.

  The second link member 72 of the link mechanism 52 has an extremely small swing range, and the axis C4 connecting the axis O3 of the fourth connecting portion 90 and the axis O4 of the fifth connecting portion 91 has a main axis C4. The frame 3 extends in a direction substantially along the length direction of the rear portion of the frame 3. A pair of ribs 93 that are parallel to each other are formed on the inner surface in the vehicle width direction of the rear portion of the main frame 3 along the length direction of the rear portion of the main frame 3. The connecting body 88 of the swing arm 40 is formed with an inclined flank 88a in order to secure a moving space in the rear lower part of the first link member 71 when the shock absorber 51 is extended most.

  The main frame 3 has a U-shaped cross section that is open on the inner side in the vehicle width direction, and the pair of ribs 93 are formed at substantially the same height as the upper and lower walls of the body frame 3.

  The link mechanism 52 is a connecting axis of the first connecting portion 81 of the first link member 71 in the process in which the shock absorber 51 expands and contracts between the most extended state shown in FIG. 7 and the most compressed state shown in FIG. O1 moves along an arcuate locus B1 (FIG. 8) protruding downward. Accordingly, the shock absorber 51 itself swings slightly downward about the axis O0 of the front end support shaft 58. Thus, in the present embodiment, when the shock absorber 51 is displaced from the most compressed state to the most extended state, the rear end portion of the shock absorber 51 moves along a locus B1 that protrudes downward. Thus, the shock absorber 51 is formed so as not to protrude downward from the lower surface of the lower frame 6 in a state where the axis C1 of the shock absorber 51 is closest to the horizontal plane. Further, when the shock absorber 51 is compressed, the diameter of the coil spring 51c increases. Even in such a case, the shock absorber 51 is configured not to protrude downward from the lower surface of the lower frame 6. .

  In addition, the relative position (swing position) of the shaft center line C1 of the shock absorber 51 with respect to the vehicle body frame 1 (lower frame 6) coincides between when the shock absorber 51 is fully extended and when it is most compressed. That is, the lever ratio of the link mechanism 52, the attachment position of each component, etc. are set so as to be the same position. In short, the shock absorber 51 once swings downward around the axis O0 of the front end support shaft 58 in the expansion and contraction process, but eventually returns to the original swing position.

  Further, in FIG. 7, at the rear end of the left swing arm bracket portion 3a, a fastening nut 86b of the second connecting portion 82 is provided from the left swing arm bracket portion 3a when the shock absorber 51 is fully extended. A recessed portion 3d that is recessed forward is formed so as to be exposed outward (leftward) in the direction. Thereby, the attachment and detachment work of the 2nd connection part 82 can be easily performed by inserting a tool from the vehicle side or back. Instead of the recess 3d, a through hole having a size that allows the tool to access the nut 86b from the side of the vehicle may be formed in the main frame 3.

  Similarly to the case of the second connecting portion 82, the connecting portion between the first link member 71 and the second link member 72, that is, the third and fourth connecting portions 83 and 90 are also the most extended of the shock absorber 51. Sometimes, the fastening nuts 83b of the third and fourth connecting portions 83, 84 are configured to be exposed outward (leftward) in the vehicle width direction from the swing arm 40 and the swing arm bracket portion 3a. Specifically, it is set so as to be exposed to the left in the vehicle width direction at an upper position with respect to the swing arm 40 and at a rear position with respect to the swing arm bracket portion 3a.

  The swing arm bracket portion 3a and the swing arm 40 may be formed with a through hole having a size that allows the tool to access the nut 83b from the side or the rear of the vehicle, or a recess recessed forward or downward. Thereby, the attachment and detachment work of the 3rd and 4th connection parts 83 and 90 can be easily performed from a vehicle side.

[Setting of the attachment position and lever ratio of each component of the link mechanism 52]
In order to make the axial center line C1 of the shock absorber 51 coincide at the time of the maximum extension and the time of the maximum compression, it can be obtained using geometric calculation. For example, the uppermost position and the lowermost position of the swing arm 40, the angle of the axial center line C1 of the shock absorber 51 with respect to the horizontal plane when the shock absorber 51 is most extended and compressed, the connection positions of the front and rear ends of the shock absorber 51, the shock absorber 51 strokes S1 are preset. In addition to these set values, the shaft cores of the connecting portions of the link members 71 and 72 are constrained by the condition that the inclination angle of the shaft core line C1 coincides when the shock absorber 51 is fully extended and compressed. By appropriately selecting the relative positions, it is possible to obtain the relative positions of the shaft centers of the respective connecting portions so that the shaft core line C1 of the shock absorber 51 coincides at the time of maximum extension and the time of maximum compression.

[Operation of the embodiment]
When the vehicle travels on an uneven road surface or a mountain field, vibration transmitted from the road surface or the like is attenuated by expansion / contraction of the front fork 17 and expansion / contraction of the shock absorber 51 of the rear suspension device 50 accompanying the swing of the swing arm 40.

  The swing arm 40 swings up and down relatively with respect to the vehicle body frame 1 with respect to the horizontal reference plane M passing through the axis O5 of the pivot shaft portion 33, and the swing arm 40 ascends from the horizontal reference plane M. In this case, that is, when the rear part of the vehicle sinks, the shock absorber 51 is compressed as shown in FIG. 8, and on the contrary, when the swing arm 40 descends from the horizontal reference plane M, that is, when the rear part of the vehicle rises. First, the shock absorber 51 extends as shown in FIG. At the same time, the link mechanism 52 changes between the state of FIG. 8 and the state of FIG.

  In FIG. 7, when the shock absorber 51 is fully extended, the fastening nut or the like at the left end of the first connecting portion 81 is positioned below the recess 40 at the lower end of the swing arm 40 and the swing arm bracket portion. It is exposed to the left in the vehicle width direction at the rear position 3a. The fastening nut 86b at the left end of the second connecting portion 82 is exposed to the left in the vehicle width direction in the recess 3D on the rear side of the swing arm bracket portion 3a. Further, the fastening nut 89b at the left end of the third and fourth connecting portions 83 and 84 is exposed to the left in the vehicle width direction at the rear side position of the swing arm bracket portion 3a. Thus, the first to fourth connecting portions 81, 82, 83, 90 are exposed to the outside in the vehicle width direction when the shock absorber 51 is fully extended, and the detachable tool is attached to the side of the vehicle or It becomes easy to access nuts from the rear.

[Effect of the embodiment]
(1) Since the shock absorber 51 disposed below the crankcase 38 of the engine 30 is disposed above the lower surface of the lower frame 6 of the vehicle body frame 1, the shock absorber 51 is moved to the road surface by the lower frame 6. It is possible to prevent the shock absorber 51 from coming into contact with the obstacle.

(2) Since the shock absorber 51 is disposed on the lower side of the crankcase 38 of the engine 30, a large space can be secured behind the engine 30, and the degree of freedom of arrangement of various equipment such as the intake box 36 and the throttle body 32 is increased. Increase.

(3) Since the shock absorber 51 is disposed on the lower side of the engine 30 along the substantially front-rear direction, the reaction force of the shock absorber 51 acts forward on the vehicle body when the vehicle body swings up and down, The pushing-up action can be prevented, and the pitching phenomenon during braking can be suppressed.

(4) Since the front end portion of the shock absorber 51 is supported by the support portion 57 protruding upward from the upper surface of the lower frame 6 so as to be swingable in the vertical direction, the shock absorber 51 can be easily attached from the side of the vehicle body. Can be done.

(5) The crankcase 38 of the engine 30 has a transmission chamber portion 38b on the rear side of the crank chamber portion 38a. The lower end surface of the crankcase 38 is such that the lower end of the transmission chamber portion 38b is the lower end of the crank chamber portion 38a. Since it is formed so as to be higher than that of the transmission chamber portion 38b, a swinging space at the rear of the shock absorber 51 swinging up and down can be secured, and the shock absorber 51 can be viewed from the side. The vehicle body frame 1 can be arranged compactly.

(6) The shock absorber 51 is a coil-over type, and includes a cylinder part 51a, a rod part 51b protruding rearward from the cylinder part 51a, a coil spring disposed on the outer peripheral side of the rod part and the latter half part of the cylinder part 51a. 51c, and the shock absorber 51 is configured so that substantially the entire body is accommodated in the vehicle body frame 1 when viewed from the side at the time of maximum compression (in FIG. 10). More accurately protected. Further, the shock absorber 51 has a cylinder portion 51a that contains oil and has a large weight disposed on the front side (oscillating shaft side), and a light rod portion 51b disposed on the rear side (free end side). The vertical swinging motion of the entire absorber 51 can be easily performed.

(7) Since the reserve tank 53 connected to the cylinder portion 51a of the shock absorber 51 via the communication pipe 54 is disposed in the heel direction in the lower end bifurcated portion of the down frame 5 in front of the shock absorber 51. The reserve tank 53 can be compactly arranged using the space in front of the shock absorber 51 without reducing the bank angle.

(8) Since the cross member 62 of the lower arm 6 is formed with a recess 62a through which the communication pipe 54 for the shock absorber 51 passes in the front-rear direction, the communication pipe 54 does not protrude upward or downward, and is compact. Can be plumbed.

(9) Since the protective plate 49 is provided to cover the lower side of the shock absorber 51, the shock absorber 51 can be protected from pebbles and gravels that are bounced from below during traveling.

(10) Since the lower engine mounting portion 31 is provided in the lower frame 6 at a position in front of the support portion 57 that supports the front end portion of the shock absorber 51, the crankcase 38 of the engine 30 itself is attached to the lower frame. 6 as a cross member, and the rigidity of the body frame 1 can be increased.

(11) The shock absorber 51 is arranged so that the axial center line C1 is rearwardly raised. While the rear end (O1) of the shock absorber 51 moves between the most compressed position and the most extended position, the shock absorber 51 moves downward. Since it moves along the convex arcuate trajectory B1, the shock absorber 51 can be disposed close to the lower surface of the crankcase 38 of the engine 30, and compactness can be achieved.

(12) Since the rear end portion of the shock absorber 51 is connected to the vehicle body frame 1 by the first and second link members 71, 72, the link mechanism 52 is utilized using the space behind the crankcase 38 of the engine 30. Can be arranged compactly.

(13) When the shock absorber 51 is fully extended, the rear end portion of the shock absorber 51 (the rear end portion of the rod portion 51) is positioned so as to overlap the lower portion of the swing arm 40 in the vehicle width direction when viewed from the side of the vehicle. Thus, the shock absorber 51 can be brought closer to the swing arm 40, and the rear part of the shock absorber 51 can be positioned as high as possible.

(14) When the shock absorber 51 is most compressed, a part of the first link side connecting portion 90 of the second link member 72 is positioned so as to overlap with the upper portion of the swing arm 40 in the vehicle width direction when viewed from the side of the vehicle. Since they are arranged, interference between the swing arm 40 and the second link member 72 can be prevented, and the swing range of the second link member 72 can be reduced.

(15) When the shock absorber 51 is most compressed, a part of the first link side connecting portion 90 of the second link member 72 is positioned so as to overlap the upper part of the swing arm 40 in the vehicle width direction when viewed from the vehicle side. Since they are arranged, interference between the swing arm 40 and the second link member 72 can be prevented, and the swing range of the second link member 72 can be reduced.

(16) When the rear end of the swing arm 40 swings upward with respect to the vehicle body frame 1, the shock absorber 51 is compressed, so that the shock absorber 51 approaches the road surface and the shock absorber 51 enters the vehicle body frame 1. The amount in which 51 is accommodated can be increased, and this also facilitates protection of the shock absorber 51.

(17) Since the drive chain 45 is disposed on the inner side in the vehicle width direction of the main frame 3 of the body frame 1 so as to pass between the main frame 3 and the link mechanism 52, the drive chain 45 is driven by the main frame 3. While protecting 45, interference between the link mechanism 52 and the drive chain 45 can be prevented, and the power of the engine 30 can be transmitted to the rear wheel 42. As a result, the shock absorber 51 of the rear suspension device 50 is disposed below the engine 30, and the interference between the drive chain 45 and the link mechanism 52 is prevented, and the power from the engine 30 is transmitted to the rear wheels 42, so that the vehicle Can be self-propelled.

(18) When the swing arm 40 swings to the uppermost position about the pivot shaft 33 at the front end (FIG. 8), the fifth of the link mechanisms 52 that is rotatably connected to the main frame 3 Since the fifth connecting portion 91 is provided so that the shaft core O4 of the connecting portion 91 is positioned above the drive chain 45, the link mechanism 52 is attached to the main frame 3 without using a bracket or the like. Even if they are directly connected, interference between the link mechanism 52 and the drive chain 45 can be prevented. Further, since a special bracket or the like is not necessary for supporting the link mechanism, it is possible to achieve weight reduction and easy assembling work. Furthermore, the load applied from the swing arm 40 to the second link member 72 can be directly and efficiently transmitted to the main frame 3.

(19) Since the connecting shaft 89 that supports the fifth connecting portion 91 of the link mechanism 52 connects the left and right frame members of the main frame 3, the connecting shaft 89 serves as a cross member of the vehicle body frame 1. As a result, the rigidity of the body frame 1 can be maintained, and the body frame parts (cross member) can be saved. Further, the rigidity of the second link member 72 constituting the link mechanism 52 can be increased.

(20) Since both side edges in the vehicle width direction of the second link member 72 are formed in a trapezoidal shape whose width in the vehicle width direction becomes narrower as it goes downward, the interference between the drive chain 45 and the link mechanism 52 is prevented. The fifth connecting portion 91 at the upper end of the link mechanism 52 can be formed wide, and the support rigidity of the link mechanism 52 can be increased.

(21) Since the connecting shaft 89 that supports the fifth connecting portion 91 at the upper end of the link mechanism 52 is disposed above the upper chain guide roller 46, interference between the drive chain 45 and the connecting shaft 89 is avoided. Thus, the assembly work and the support mechanism of the link mechanism 52 can be simplified.

(22) The width in the vehicle width direction of the fifth connecting portion 91 at the upper end of the second link member 72 is formed larger than the width in the vehicle width direction of the swing arm 40, and the fourth at the lower end of the second link member 72. Since the width of the connecting portion 90 in the vehicle width direction is formed to be smaller than the interval in the vehicle width direction of the swing arm 40, the interference between the swing arm 40 and the link mechanism 52 is prevented, and the rotation amount of the second link member 72 is Can be increased.

(23) The width in the vehicle width direction of the third connecting portion 83 at the upper end of the first link member 71 is formed smaller than the width in the vehicle width direction of the second connecting portion 82 connected to the swing arm 40. Therefore, it is not necessary to form a recess for escape in the swing arm 40 so as not to interfere with the connecting portion 83 of the first and second link members 71, 72, and the shape of the swing arm 40 is prevented from being complicated, Manufacturing can be facilitated. Furthermore, a space for tool insertion can be secured between the swing arm 40 and the connecting portion 83, and the assembling work is facilitated.

(24) The chain transmission device includes an upper chain guide roller 46 disposed above the upper (tension side) drive chain 45, and the fifth connecting portion 91 at the upper end of the link mechanism 52 is an upper chain guide. Since it is disposed above the roller 46, interference between the link mechanism 52 and the drive chain 45 can be more effectively prevented.

(25) Since the upper chain guide plate 48a for guiding the tight side portion of the drive chain 45 from the lower side is provided on the upper surface of the swing arm 40, the drive is performed regardless of the vertical swing of the swing arm 40. The chain 45 can be smoothly guided backward without rattling.

(26) The shock absorber 51 is compressed and expanded as the swing arm 40 is raised and lowered (sinking and lifting of the rear portion of the vehicle). In the expansion and contraction process between the maximum extension and the maximum compression, the shock absorber 51 The shaft 58 swings slightly downward about the axis O0 of the support shaft 58, and the swing position coincides between the maximum compression and the maximum expansion. Therefore, the load applied to the swing arm 40 can be efficiently absorbed by the shock absorber 51.

(27) Since the vertical swing range of the shock absorber 51 with respect to the vehicle body frame 1 (lower frame 6) can be reduced, the space around the shock absorber 51 can be effectively used to arrange other parts and equipment. . Further, since the ground clearance can be increased, contact between the shock absorber 51 and the ground during traveling on the uneven surface is prevented.

(28) The connecting shaft core O1 of the first connecting portion 81 of the first link member 71 connected to the rear end portion of the shock absorber 51 is lowered between when the shock absorber 51 is fully extended and when it is compressed most. Therefore, the shock absorber 51 can be arranged close to the lower surface of the engine while avoiding interference between the shock absorber 51 and the lower surface of the engine 30.

(29) Since the shaft core line C1 connecting the shaft cores O0 and O1 at the front and rear end portions of the shock absorber 51 is inclined upward toward the rear at the time of the most compression (and at the time of the maximum expansion), the first connection When the connecting shaft core O1 of the portion 81 (the rear end portion of the shock absorber 51) moves along the arcuate locus B1, it becomes easy to prevent contact between the rear end portion of the shock absorber 51 and the road surface.

(30) Since the rear end portion of the shock absorber 51 is connected to the vehicle body frame 1 by the first and second link members 71, 72, the link mechanism 52 is utilized using the space behind the crankcase 38 of the engine 30. Can be arranged compactly.

(31) Since the second connecting portion (arm-side connecting portion) 82 is connected to the swing arm 40 at a position higher than the center line of the vertical width of the swing arm 40, the second connecting portion 82 The distance (first lever length L1) between the shaft core O2 and the shaft core O1 of the first connecting portion (shock-side connecting portion) 81 can be increased, whereby the most compressed position and the most extended position can be increased. The radius of the arcuate trajectory B1 can be increased, and the swinging of the shock absorber 51 between the most extended position and the most compressed position can be suppressed.

(32) When the shock absorber 51 is compressed most, the second connecting portion (arm-side connecting portion) 82 of the first link member 71 is overlapped with the swing arm bracket portion 3a in the vehicle width direction when viewed from the vehicle side. Therefore, the second connecting portion 82 is disposed at a position close to the pivot shaft portion 33 of the swing arm 40, whereby the second connecting portion by the swinging up and down of the swing arm 40 is arranged. The amount of vertical movement of the portion 82 can be reduced.

(33) When the shock absorber 51 is fully extended, the rear end portion of the shock absorber 51 (the rear end portion of the rod portion 51) is positioned so as to overlap the lower portion of the swing arm 40 in the vehicle width direction when viewed from the side of the vehicle. Thus, the shock absorber 51 can be brought closer to the swing arm 40, and the rear part of the shock absorber 51 can be positioned as high as possible.

(34) When the shock absorber 51 is most compressed, a part of the fourth connecting portion 90 of the second link member 72 is disposed at a position overlapping the upper portion of the swing arm 40 in the vehicle width direction when viewed from the side of the vehicle. Therefore, interference between the swing arm 40 and the second link member 72 can be prevented, and the swing range of the second link member 72 can be reduced.

(35) The shock absorber 51 is a coil-over type, and a large-diameter coil spring 53 is disposed at the rear part of the shock absorber 51 and a heavy cylinder part 51a is disposed at the front part. The shock absorber 51 can be arranged compactly in the vertical direction, and the inertial force at the time of swinging can be kept small, so that the shock absorbing performance is good.

(36) Since the reserve tank 53 connected to the cylinder portion 51a of the shock absorber 51 by the communication pipe 54 is disposed facing the front side of the shock absorber 51, the free space on the front side of the shock absorber 51 is reserved. It can be used effectively for the tank 53.

(37) Since the shock absorber 51 is disposed on the lower side of the engine 30 substantially in the front-rear direction, the reaction force of the shock absorber 51 acts forward on the vehicle body when the vehicle body swings up and down, and pushes it up against the rider. The action can be prevented, and the pitching phenomenon during braking can also be suppressed.

(38) Since the link mechanism 52 is configured so that the shock absorber 51 is compressed when the swing arm 40 is lifted, the axial center line C1 of the shock absorber 51 is in the rearward direction when the swing arm is lifted so that the vehicle body sinks downward. By inclining so as to incline upward as it travels, it is possible to easily prevent the shock absorber 51 from contacting the road surface obstacle.

(39) In the vehicle side view, the rear end portion of the shock absorber 51 is configured to overlap the pair of arm portions of the swing arm 40 when the shock absorber 51 is fully extended. In other words, the swing arm 40 is formed with a recess 40b having a lower opening in which the rear end portion of the shock absorber 51 is accommodated when the shock absorber 51 is fully extended. Thereby, the rear end portion of the shock absorber 51 at the time of maximum extension can be positioned as high as possible, and the axial center axis C1 of the shock absorber 51 can be easily formed rearward.

(40) Since the lower end of the support shaft 58 that supports the front end portion of the shock absorber 51 is positioned above the upper surface of the lower frame, the lower end of the shock absorber 51 is disposed above the lower surface of the lower frame 6. It's easy to do.

(41) The support portion 57 that supports the support shaft 58 at the front end portion of the shock absorber 51 is formed integrally with a cross member 62 extending in the left-right direction, and the cross member 62 connects the left and right lower frames 6 together. Yes. As a result, the impact transmitted from the shock absorber 51 can be distributed and transmitted to the left and right lower frames 6 respectively. Further, since the engine lower mounting portion 31 is disposed in front of the support portion 57, the shock from the shock absorber 51 is transmitted from the left and right lower frames 6 to the engine case such as the crankcase 38. As a result, an impact can be received by the crankcase 38, and the rigidity against the impact can be increased by suppressing the frame rigidity. Further, the engine case such as the crankcase 38 can be distributed to the pair of left and right upper mounting portions 32 and the front mounting portion 34 to transmit an impact.

(42) The support portion 57 at the front end portion of the shock absorber 51 and the lower attachment portion 31 of the engine 30 are integrally formed with the cross member 62, and the cross member 62 is welded to the pair of left and right lower frames 6, or It is concluded. Therefore, the cross member 62 also functions as a connection portion that extends in the front-rear direction and connects the support portion 57 and the lower attachment portion 31 in the front-rear direction. Thereby, the impact transmitted to the shock absorber 51 is transmitted to the front mounting portion 31 from the support portion 57 through the cross member 62, so that the impact can be transmitted smoothly.

(43) Since the protection plate 49 is provided on the lower surface of the lower frame 6, the displacement of the communication pipe 54 of the shock absorber 51 is restricted by the protection plate 49, and thereby the communication pipe 54 below the lower frame 6. Is prevented from protruding. Since the communication pipe 54 can be protected by the pair of left and right lower frames 6 and the protection plate 49, even if the shock absorber 51 swings up and down, the communication pipe 54 is prevented from interfering with other equipment and the road surface. Can do.

(44) The reserve tank 53 of the shock absorber 51 is disposed so that the axial center line C1 thereof is substantially parallel to the bifurcated portion of the lower end of the down tube 5, so that the compact between the bifurcated portions of the down tube 5 is compact. The space at the lower end portion of the down tube 5 can be effectively used.

(45) Since the front area of the reserve tank 53 and the communication pipe 54 is covered with the protection plate 49, the communication pipe 54 and the reserve tank 53 can be protected from the front.

(46) Since the link mechanism 52 that faces the chain roller 46 in the vehicle width direction is disposed at a distance from the chain roller 46 in the vehicle width direction, interference between the chain roller 46 and the link mechanism 52 is avoided. It is done.

(47) The connecting shaft 89 that supports the fifth connecting portion 91 at the upper end of the link mechanism 52 is detachably fastened to the main frame 3 by a nut 89a that protrudes outward in the vehicle width direction of the main frame 3. Therefore, for example, the attaching / detaching operation of the connecting shaft 89 is easier than the structure in which the link mechanism is supported on the vehicle body frame via the support member.

(48) Since the connecting shaft 89 that supports the fifth connecting portion 91 at the upper end of the link mechanism 52 is disposed in front of and above the chain roller 46, even if the drive chain 45 swings upward. Interference between the connecting shaft 89 and the drive chain 45 can be prevented more reliably.

(49) The side surface of the first link member 71 on the drive chain arrangement side, that is, the left side surface is arranged on the right side with an interval in the vehicle width direction with respect to the swing arm 40 and the main frame 3. Of the link member 71, the third connecting portion 83 connected to the second link member 72 is formed at a position retracted inward (rightward) in the vehicle width direction from the left side surface. Connection portions (third and fourth connection portions 83 and 90) between the first link member 71 and the second link member 72 are located inward in the vehicle width direction from the left side surface of the first link member 71. . As a result, one end surface (left end surface) in the vehicle width direction of the fastening portions (third and fourth connecting portions 83 and 90) of the link members 71 and 72 is more inward in the vehicle width direction than the chain line. It becomes easy to position.

[Other embodiments]
(1) The present invention only requires that a shock absorber is disposed above the lower surface of the lower frame, and the vehicle body frame can be applied to a vehicle body frame having a configuration different from that of the above embodiment. For example, the main frame may have a structure that branches from the head pipe in the vehicle width direction and then branches to the left and right, and the down frame has a structure that branches to the left and right immediately after the head pipe. It may be.

(2) In the present invention, it is preferable that the shock absorber is positioned above the lower surface of the lower frame at any swing position of the swing arm swinging up and down. It is sufficient that the shock absorber is above the lower surface of the lower frame when the drive source such as the engine is lowered to the lowest position in the state where it is raised most with respect to the frame, that is, when the vehicle body is depressed most. Therefore, for example, when the rear end of the swing arm is lowered relative to the body frame and the drive source such as the engine is raised to a relatively high position, the lower end of the shock absorber is lower than the lower surface of the lower frame. A configuration located below is also included.

(3) In the above-described embodiment, as shown in FIG. 8, when the shock absorber 51 is most compressed, except for the rear end portion of the shock absorber 51, substantially the entire shock absorber 51 is viewed from the side of the vehicle. Although the structure fits within the body frame 1, the present invention may have a structure in which most of the rod portion of the shock absorber 51 protrudes rearward from the body frame 1 even when the shock absorber 51 is compressed most. it can. In this case, it is preferable to extend the protection plate 49 to the rear of the vehicle body frame 1 to protect the rear end portion of the shock absorber 51.

(4) Although the engine (internal combustion engine) is mounted as a drive source in the above embodiment, the present invention can also be applied to a motorcycle mounted with another drive source such as an electric motor.

(5) The link mechanism is not limited to the shape of the above-described embodiment, and other forms can be adopted. For example, the first link member constituting the link mechanism is not limited to the bell crank type, and may be a linear link member. Moreover, it can also be set as the link mechanism which does not have a 2nd link member.

(6) The present invention can also be applied to a motorcycle including a single cylinder type shock absorber having no coil as a shock absorber.

(7) In the above embodiment, the fifth connecting portion (frame side connecting portion) 91 of the link mechanism 52 is supported by the main frame 3 so as to be freely rotatable. Thus, a support member (bracket) can be disposed at a right interval, and the fifth connecting portion 91 of the link mechanism 52 can be supported by the support member. As a result, a space in the vehicle width direction through which the endless body can pass can be formed between the link mechanism 52 and the main frame 3. By forming a space in this way, it is possible to avoid interference between the link mechanism 52 and the endless body (drive chain 45) while increasing the degree of freedom in designing the upper end portion (fifth connecting portion 91) of the link mechanism 52. it can.

(8) The present invention is applicable to a saddle riding type vehicle having a belt type transmission device using a belt and a pulley in addition to a chain type transmission device using a chain and a sprocket (gear) as a winding transmission device. Is possible.

(9) In the above embodiment, the rotatable chain guide roller 46 is provided as a member for restricting the upward movement of the endless body. However, the upward movement of the endless body can be regulated even if it is not a rotary type. For example, a resin guide body may be provided. Furthermore, it is also possible to adopt a structure in which a roller or a guide body is provided on a part of the connecting shaft 89 that supports the fifth connecting portion 91 of the link mechanism 52.

(10) In the above-described embodiment, it has been described that the shaft core line C1 (FIG. 8) of the shock absorber 51 coincides between the maximum extension time and the maximum compression time. A case of deviation is also included in the present invention. For example, while moving from the maximum extension to the maximum compression, the shock absorber shaft core line should be separated from the shock absorber shaft core line at the maximum extension and then close to the shaft core line of the shock absorber at the maximum extension. Therefore, the swing amount of the shock absorber can be reduced with respect to the swing amount of the swing arm, and such a configuration is also included in the present invention.

(11) The reserve tank 53 of the shock absorber 51 preferably extends in the direction perpendicular to the left-right direction so that the reserve tank 53 is disposed between the left and right frames. It may be arranged in the front-rear direction between the lower frames.

(12) As the shock absorber, a single cylinder type shock absorber having no coil can be provided.

(13) The shape of the bottom surface of the crankcase is not limited to the shape of the above-described embodiment, and for example, it can be a shape formed in a step-up manner.

(14) In the embodiment described above, the first link member is provided with three connecting portions, but the positions of the connecting shaft cores (O1, O2, 03) may be set at different positions. Also, it is not always necessary to set the end portion. Furthermore, the vertical position may be different. For example, a 1st connection part or a 3rd connection part may be arrange | positioned in the intermediate part. Further, for example, the second connecting portion may be arranged in front of or below the pivot shaft portion.

(15) The motorcycle to which the present invention is applied can be particularly suitably used for a vehicle traveling on rough terrain, for example, a motocross vehicle. Specifically, the present invention is preferably applied to a vehicle in which the swinging amount of the swing arm is relatively large or travels on a rough road surface, and a large impact due to the vertical movement of the rear wheel is applied to the vehicle body via the suspension. . Further, the present invention is not limited to this, and the present invention can also be applied to a vehicle for leveling traveling.

1 Body frame 3 Main frame 6 Lower frame 30 Engine (drive source)
31 Lower engine mounting part (Mounting part for drive source)
38 Crankcase 40 Swing arm 49 Protective cover 50 Rear suspension device 51 Shock absorber 51a Cylinder portion 51c Coil spring 52 Link mechanism 53 Reserve tank 54 Communication pipe 62 Cross member 62a Recessed portion 57 Shock absorber support portion 71 First link member 72 Second link Link member C1 Shaft absorber shaft core wire

Claims (8)

The vehicle body frame has a lower frame extending below the drive source, and in the motorcycle in which the shock absorber of the rear suspension device is disposed below the drive source,
The motorcycle, wherein the shock absorber is disposed so as to be substantially along the front-rear direction, and the lower end of the shock absorber is disposed above the lower surface of the lower frame. The motorcycle according to claim 1, wherein
The lower frame is provided with a pair of left and right,
The shock absorber is a motorcycle disposed between the left and right lower frames. The motorcycle according to claim 1 or 2,
A motorcycle, wherein a front end portion of the shock absorber is supported by a support portion provided above the upper surface of the lower frame so as to be swingable in the vertical direction. The motorcycle according to any one of claims 1 to 3,
A motorcycle in which a reserve tank connected to a cylinder portion of the shock absorber via a communication pipe is disposed in front of the shock absorber in a saddle direction. The motorcycle according to claim 4 quoting claim 2.
A motorcycle in which a recess that allows the communication pipe to pass in the front-rear direction is formed in a cross member that connects the pair of left and right lower frames. The motorcycle according to any one of claims 1 to 5,
A motorcycle comprising a protective plate that covers a lower side of the shock absorber. The motorcycle according to any one of claims 1 to 6,
The lower frame is provided with a drive source mounting portion at a position ahead of a front end support portion of the shock absorber. The motorcycle according to any one of claims 1 to 7,
The shock absorber is disposed such that the axial center line is raised rearward,
A motorcycle that moves along a downward arcuate locus while the rear end of the shock absorber moves between the most compressed position and the most extended position.

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