JP6161980B2 - Motorcycle - Google Patents

Description

  The present invention relates to a motorcycle including a rear suspension device that supports a swing arm for a rear wheel by a shock absorber and a link mechanism disposed below a drive source such as an engine.

  FIG. 12 shows an example of the motorcycle having the above-described configuration (Patent Document 1). The vehicle body frame 205 includes a main frame 205a that extends rearward and downward from the head pipe 204. The rear end of the main frame 205a is It extends substantially vertically downward and forms a swing arm bracket portion 205b. The swing arm 202 that supports the rear wheel 201 is supported on the pivot shaft portion of the swing arm bracket portion 205b so as to be swingable in the vertical direction, and is elastically connected and supported to the vehicle body frame 205 by the rear suspension device 203. Yes. The rear suspension device 203 includes a shock absorber 207 disposed on the lower side of the engine 206 and a link mechanism 210 disposed on the rear side of the engine 206. The upper end portion of the upper link member 210a of the link mechanism 210 is rotatably connected to the upper end portion of the swing arm bracket portion 205b.

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

  In the motorcycle shown in FIG. 12, when viewed from the side of the vehicle, the axis C4 of the upper link member 210a and its forward extension portion gradually move downward from the main frame 205a with respect to the main frame 205a. Thus, it is relatively inclined (inclination angle θ), extends forward without intersecting with the main frame 205a, and further passes forward under the head pipe 204.

  Further, when the rear portion of the vehicle sinks from the state of FIG. 12 and the rear end portion of the swing arm 202 rises relative to the vehicle body frame 205, the shock absorber 207 is compressed, and the upper link member 210a with respect to the main frame 205a is compressed. The inclination θ of the axial center line C4 increases.

  In the above-described conventional structure, the load applied to the main frame 205a from the swing arm 202 via the upper link member 210a is mostly a bending load and further applied in a direction deviating downward from the head pipe 204. Therefore, it is necessary to maintain the durability and rigidity of the vehicle body frame against the load applied from the swing arm.

  An object of the present invention is to provide a motorcycle capable of maintaining the durability and rigidity of a vehicle body frame against a load applied from a swing arm without increasing the vehicle body frame or increasing its weight.

  In order to solve the above-described problems, the first invention of the present application is configured to elastically attach a swing arm for a rear wheel to a vehicle body frame by a shock absorber and a link mechanism arranged substantially along the front-rear direction below the drive source. In a motorcycle including a rear suspension device that supports the link mechanism, the link mechanism includes a link member that is pivotably connected to the vehicle body frame above the swing arm, and the link member has a shaft thereof. The front extension portion of the core wire is assembled so as to follow the axial core wire of the frame portion extending forward and upward from the connection point between the link member and the vehicle body frame.

  According to the first invention of the present application, the load applied to the vehicle body frame from the swing arm via the link member acts so as to compress or pull the frame portion of the vehicle body frame in the longitudinal direction. The durability and rigidity of the vehicle body frame against the load applied from the swing arm can be maintained without increasing the cross section) or increasing the weight. Particularly, since the frame portion and the link member are aligned on the same straight line when the shock absorber is compressed most when the load is applied to the swing arm, the rigidity can be increased when actually required.

    The first invention of the present application has the following configuration in addition to the configuration of the motorcycle.

(A) One or a plurality of ribs extending along the axial line of the frame portion are formed on the frame portion of the body frame.

  According to the configuration (a), the rigidity of the vehicle body frame against the load from the swing arm can be further improved.

(B) The front end portion of the shock absorber is supported by the lower frame of the vehicle body frame. In this case, preferably, the support portion that supports the front end portion of the shock absorber is provided on the lower frame in the vicinity of the attachment portion to which the drive source is attached.

  According to the configuration (b), the load from the swing arm can be distributed to the frame portion of the body frame (a part of the main frame and the lower frame), the rigidity of the body frame can be ensured, and the weight can be reduced. Since the support portion of the front end portion of the shock absorber is provided in the lower frame portion in the vicinity of the attachment portion for attaching the drive source, the drive source can be used as a rigid member, and the body frame can be prevented from being enlarged.

  A second invention of the present application includes a rear suspension device that elastically supports a swing arm for a rear wheel on a vehicle body frame by a shock absorber and a link mechanism that are disposed substantially along the front-rear direction below the drive source. In the motorcycle, the link mechanism has a link member that is pivotably connected to the vehicle body frame above the swing arm, and the link member has a front extension portion of its axis. As viewed from the side of the vehicle, it is assembled so as to cross the main frame of the main frame.

  According to the second invention of the present application, the load applied from the swing arm to the vehicle body frame has a large ratio of acting as a bending load, but the extension part of the axial center line of the upper link member intersects the vehicle body frame in a side view. Compared with the conventional structure as shown in FIG. 11, the durability and rigidity of the body frame against the load applied from the swing arm can be maintained without increasing the body frame or increasing the weight.

  The second invention of the present application can be set to a specific mode as follows, and any mode can exhibit the same effect as described above.

(C) When the shock absorber is in a compressed state and the swing arm is raised with respect to a horizontal line passing through the axis of the pivot shaft portion at the front end, a forward extension portion of the shaft core wire of the link member is The vehicle crosses the main frame when viewed from the side of the vehicle.

(D) When the shock absorber is in an extended state and the swing arm is lowered with respect to a horizontal line passing through the axis of the pivot shaft at the front end, a forward extension portion of the axis of the link member is The vehicle crosses the main frame when viewed from the side of the vehicle.

(E) When the shock absorber is most compressed or extended, a forward extension portion of the shaft core wire of the link member intersects the main frame when viewed from the side of the vehicle.

(F) In the entire stroke from when the shock absorber is fully compressed to when it is fully extended, the forward extension portion of the axial core of the link member intersects the main frame when viewed from the side of the vehicle.

  In short, according to the present invention, the durability and rigidity of the body frame against the load applied from the swing arm can be maintained without increasing the body frame (enlarging the cross section) or increasing the weight.

1 is a left side view of a motorcycle according to a first invention of the present application. 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 left side view of a motorcycle according to a second invention of the present application. FIG. 10 is a left side view of the rear suspension device of FIG. 9 when the shock absorber is fully extended. FIG. 10 is a left side view of the rear suspension device of FIG. 9 when the shock absorber is fully compressed. FIG. 6 is a side view of a conventional motorcycle.

[First embodiment]
An embodiment of the first invention of the present application 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.

[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 substantially vertically 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 drive source is an engine (internal combustion engine) 30. The engine 30 is mounted in the vehicle body frame 1, and is provided on the main frame 3 and a pair of left and right lower mounting portions 31 provided on the lower frame 6. The body frame 1 is supported by a pair of left and right upper mounting portions 32, a pivot shaft portion 33 of the swing arm bracket portion 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 the present embodiment, the connection structure in each connection portion is configured to be relatively rotatable between the objects to be connected by being connected via pins.

  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 is The front extension portion is attached so as to substantially coincide with the axial center line C3 of the straight rear frame portion of the main frame 3. In this embodiment, as shown in FIG. 8, the second link is when the rear end of the swing arm 40 is raised most relative to the vehicle body frame 1 and when the shock absorber 51 is most compressed. A front extension portion of the axial line C4 of the member 72 is attached so as to substantially coincide with the axial line C3 of the rear portion of the main frame 3. Therefore, as shown in FIG. 7, the rear end of the swing arm 40 descends relative to the vehicle body frame 1, and when the shock absorber 51 is fully extended, the axial line C <b> 4 of the second link member 72 and the main frame 3 intersects with the axis C3 of the rear frame portion at a slight angle.

  A pair of ribs 93 are formed on the inner surface in the vehicle width direction of the rear frame portion of the main frame 3 along the length direction of the frame portion and parallel to the axis C3. 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 by 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) As for the 2nd link member 72 which comprises the upper part of the link mechanism 52, the 5th connection part 91 of the upper end part is connected with the swing arm bracket part 3a of the main frame 3 so that rotation is possible, Since the second link member 72 is assembled so that the front extension portion of the axial center line C4 of the two link member 72 is substantially coincident with the axial center line C3 of the linear rear frame portion of the main frame 3, the swing arm Most of the load applied from 40 to the main frame 3 via the first and second link members 71 and 72 acts to compress or pull the rear frame portion of the main frame 3 in the length direction. Thereby, the durability and rigidity of the body frame 1 against the load applied from the swing arm 40 can be maintained without increasing the body frame 1 (enlarging the cross section) or increasing the weight.

(2) In particular, when the shock absorber 51 is most compressed when the load is applied to the swing arm 40, the axial line C3 of the rear frame part of the main frame 3 and the extended part of the axial line C4 of the second link member 72 However, since they are aligned on the same straight line, the rigidity can be increased when actually required.

(3) Since the rib 92 extending substantially parallel to the axial center line C3 is formed on the straight rear frame portion of the main frame 3, the rigidity of the body frame 1 with respect to the load from the swing arm 40 is further improved. be able to.

(4) Since the clevis 51e at the front end of the shock absorber 51 is supported by the support portion 57 provided on the lower frame 6 of the vehicle body frame 1, the load applied to the vehicle body frame 1 from the swing arm 40 is Accordingly, the rigidity of the vehicle body frame 1 can be secured and the weight can be reduced. In addition, since the support portion 57 is provided on the lower frame 6 in the vicinity of the engine lower side attachment portion 31, the engine 30 itself can be used as a rigid member of the vehicle subframe 1 and the large body frame can be used. Can be prevented.

(5) Since the shock absorber 51 is arranged below 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.

(6) 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.

The (7) swing arm 40, (FIG. 8) when swung to the most upper position about the Pivot shaft portion 33 of the front end, of the link mechanism 52 is rotatably connected to the main frame 3 Since the fifth connecting portion 91 is provided so that the axis O4 of the fifth connecting portion 91 is positioned above the drive chain 45, the link mechanism 52 is not used on 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.

(8) 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 parts for the body frame (cross member) can be saved. Further, the rigidity of the second link member 72 constituting the link mechanism 52 can be increased.

(9) 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.

(10) 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.

(11) 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 to be 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.

(12) 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.

(13) When the shock absorber 51 is compressed most, 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.

(14) 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 89 a 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.

(15) 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.

(16) 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.

[Second Embodiment]
9 to 11 show a second embodiment of the present application. Compared to the first embodiment, the shape of the frame portion at the rear of the main frame 3 and the frame portion and the second link member 72 are shown. The relative positional relationship is different, the other structures are the same, and the same parts or portions as those in the first embodiment are denoted by the same reference numerals or numbers.

  In FIG. 10, the link support part 3b formed in the upper end part of the swing arm bracket part 3a is located in the front end part of the swing arm bracket part 3a. Accordingly, the fifth connecting portion 91 at the upper end portion of the second link member 72 is also located at the front end portion of the swing arm bracket portion 3a when viewed from the side of the vehicle.

  As shown in FIG. 10, when the shock absorber 51 is at its maximum extension and the swing arm 40 is in the state of being most lowered with respect to the horizontal line M passing through the axis 05 of the pivot shaft 33, the second link The front extension portion of the axial line C4 of the member 72 intersects with the axial line C3 of the linear frame portion at the rear of the main frame 3 at an acute crossing angle (inclination angle) θ1, and is shown in FIG. As described above, even when the shock absorber 51 is most compressed and the swing arm 40 is in the most elevated state with respect to the horizontal line M passing through the axis 05 of the pivot shaft portion 33, the rear portion of the main frame 3. Crossing with the axis C3 of the straight frame portion at an acute crossing angle (inclination angle) θ2. However, the crossing angle θ2 when the shock absorber 51 of FIG. 11 is most compressed is smaller than the crossing angle (tilt angle) θ1 when the shock absorber 51 of FIG.

In this embodiment, the load applied to the vehicle body frame 1 from the swing arm 40 has a large ratio of acting as a bending load, but the front extension portion of the axial center line C4 of the second link member 72 is the main frame 3 in a side view. Since it intersects with the rear frame portion at an acute crossing angle θ2 or θ1, it is applied from the swing arm 40 without increasing the body frame 1 or increasing the weight as compared with the conventional structure as shown in FIG. The durability and rigidity of the body frame 1 with respect to the load can be maintained.
[Other embodiments]
(1) 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.

(2) The link mechanism is not limited to the shape of the above 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.

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

(4) The shape of the bottom surface of the crankcase is not limited to the shape of the above-described embodiment, and for example, a shape that is formed in a step-up manner and rearwardly rising may be used.

(5) 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.

(6) 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.

DESCRIPTION OF SYMBOLS 1 Body frame 3 Main frame 3a Swing arm bracket part 6 Lower frame 30 Engine (drive source)
31 Lower engine mounting part (Mounting part for drive source)
40 Swing Arm 50 Rear Suspension Device 51 Shock Absorber 52 Link Mechanism 57 Shock Absorber Support 71 71 First Link Member 72 Second Link Member C4 Axis Core Line of the First Link Member C3 Axis Core Line of the Rear Part of the Body Frame

Claims (8)

In a motorcycle including a rear suspension device that elastically supports a swing arm for a rear wheel on a vehicle body frame by a shock absorber and a link mechanism arranged substantially along the front-rear direction below the drive source.
The link mechanism has a link member that is rotatably connected to the vehicle body frame above the swing arm,
The link member is assembled such that the front extension portion of the axial center line (C4) is along the axial center line of the frame portion extending forward and upward from the connection point between the link member and the body frame,
The link member is rotatably connected to the main frame of the vehicle body frame via a connecting shaft,
The motorcycle according to claim 1, wherein the connecting shaft is provided in an axial core portion along an axial core line (C3) of a swing arm bracket portion of the swing arm .
2. The motorcycle according to claim 1, wherein the link member is assembled such that a forward extension portion of the axis line (C4) of the link member substantially coincides with or intersects with the axis line (C3) of the swing arm bracket portion. .
The axial center line (C3) of the swing arm bracket part and the front extension part of the axial center line (C4) of the link member are aligned on the same straight line when the shock absorber is compressed most. Motorcycle.
The vehicle body frame has a head pipe and a pair of left and right main frames extending substantially rearward and downward from the head pipe,
  The motorcycle according to any one of claims 1 to 3, wherein the connecting shaft functions as a cross member that couples the pair of left and right main frames.
The motorcycle according to claim 4, wherein the connecting shaft is detachably fastened to the pair of left and right main frames.
In a motorcycle including a rear suspension device that elastically supports a swing arm for a rear wheel on a vehicle body frame by a shock absorber and a link mechanism arranged substantially along the front-rear direction below the drive source.
The link mechanism has a link member that is rotatably connected to the vehicle body frame above the swing arm,
The link member is assembled such that the front extension portion of the axial center line crosses the main frame of the body frame when viewed from the side of the vehicle,
The motorcycle according to claim 1, wherein a link support portion that supports the link member is located at a front end portion of a swing arm bracket portion of the swing arm .
When the shock absorber is in a compressed state and the swing arm is raised with respect to a horizontal line passing through the axis of the pivot shaft portion at the front end, or when the shock absorber is in an extended state, the swing arm is When the shock absorber is in a state of being lowered with respect to a horizontal line passing through the axis of the pivot shaft at the front end, or when the shock absorber is at the most compressed or extended position, or when the shock absorber is at the most compressed or extended position. In the whole process
  The motorcycle according to claim 6, wherein a forward extension portion of the shaft core of the link member intersects with the main frame when viewed from the side of the vehicle.
The motorcycle according to claim 6, wherein a crossing angle between the link member and the main frame when the shock absorber is compressed most is smaller than the crossing angle when the shock absorber is extended most.

Images