JP4247839B2 - Motorcycle body structure - Google Patents

Description

  The present invention relates to a vehicle body structure of a motorcycle that includes a vehicle body frame and a rear wheel swing arm, and that has a rear suspension interposed therebetween.

  In a motorcycle having a rear suspension for a rear wheel, a rear suspension is generally disposed at the center of the vehicle width, and the front end of the rear suspension is connected to a cross member of a vehicle body frame. It is transmitted to the vehicle body frame via a member.

As another example of the arrangement of the rear suspension, there is a vehicle type in which the rear suspension is arranged on the side of the engine arranged in the body frame, and the rear suspension is interposed between the front end portion of the body frame and the swing arm. (Refer to patent document 1 etc.).
JP 2001-106155 A

  If the front end of the rear suspension is connected to the cross member of the body frame as in the past, the load from the swing arm is first transmitted to the cross member, and then to the main frame member. The member is a member arranged in the vehicle width direction, and therefore the load from the swing arm is a lateral load with respect to the cross member. Further, since the rear suspension is usually attached via a support bracket protruding from the cross member, the load transmitted from the swing arm is applied eccentrically to the cross member, and a torsional moment is generated in the cross member. Therefore, the cross member is required to have high rigidity, and as a result, there is a problem in that the weight of the cross member is increased, and consequently, the weight of the body frame is increased.

(Object of invention)
The present invention solves the above-mentioned problems, reduces the burden on the cross member due to the load transmitted from the swing arm via the rear suspension, and reduces the weight of the vehicle body frame including the cross member. The purpose is to provide.

According to a first aspect of the present invention, a vehicle body frame and a rear wheel swing arm supported by the vehicle body frame so as to be swingable up and down are provided, and a rear suspension is provided between the vehicle body frame and the rear wheel swing arm. In the vehicle body structure of the interposed motorcycle, the vehicle body frame has a pair of left and right main frame members extending rearward from the head pipe, and a cross member connecting between the rear end portions of the main frame members. The cross member has a support boss that swingably supports an end portion of the rear suspension at a connection portion with the main frame member, and a swing fulcrum of the rear suspension in the support boss is wherein it is arranged on the cross member and on approximately the same axis, so that the swing fulcrum, intersects the central axis of the rear end portion of the adjacent main frame member Characterized in that it is location.

  According to this, since the swing fulcrum of the rear suspension is arranged coaxially with the cross member, a torsional moment is not generated in the cross member due to the load applied to the cross member from the swing arm via the rear suspension. The burden on the cross member can be reduced. Accordingly, it is possible to reduce the weight of the cross member, and thus the body frame. Further, since the swing fulcrum of the rear suspension does not protrude front and rear and up and down with respect to the cross member, the appearance from the side is also improved. Further, since the support boss is provided at the connection portion with the main frame member, the load transmitted from the swing arm via the rear suspension can be directly transmitted to the main frame member.

According to a second aspect of the present invention , a vehicle body frame and a rear wheel swing arm supported by the vehicle body frame so as to swing up and down are provided, and a rear suspension is provided between the vehicle body frame and the rear wheel swing arm. In the vehicle body structure of the interposed motorcycle, the vehicle body frame has a pair of left and right main frame members extending rearward from the head pipe, and a cross member connecting between the rear end portions of the main frame members. The cross member has a support boss that swingably supports an end portion of the rear suspension at a connection portion with the main frame member, and a swing fulcrum of the rear suspension in the support boss is the cross member and is disposed substantially coaxially mind, the rear suspension, the main frame members and on substantially the same straight line when viewed from the side in Characterized in that it is location.

  According to this, the main frame member can receive most of the load transmitted from the swing arm via the rear suspension as an axial load, improving the load resistance against the swing arm and reducing the weight of the main frame member. Is possible.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein the cross member has a main body extending in the left-right direction and the support boss fixed to an end of the main body. the support boss, a pair of shaft support portions for supporting both ends of the swing shaft of the rear suspension, as well as connected to each other with the hinge supporting portion, connecting portion connected to the rear end portion of the main frame member It is characterized by having.

  According to this, among the cross members, the strength of the support boss (the strength of the connecting portion) to which the rear suspension is coupled and the main frame member is coupled can be partially increased, and the strength of the entire cross member is increased. The weight can be reduced compared to the above.

  According to the present invention, it is possible to reduce the burden on the cross member due to the load transmitted from the swing arm via the rear suspension, and to reduce the weight of the vehicle body frame including the cross member.

  FIG. 1 is a right side view of a body frame or the like of a motorcycle according to an embodiment of the present invention, and FIG. 2 is a left side view of the body frame or the like. In these drawings, the body frame 10, the swing arm 11 and the rear suspension 12 are shown by solid lines, the engine 13, the front and rear wheels 14, 15 and the front fork 16 are shown by phantom lines, and other parts are omitted. ing.

[Body frame structure]
FIG. 3 is a perspective view of the vehicle body frame 10, and the vehicle body frame 10 is mainly composed of a front frame body 8 disposed on the front side and a rear frame body 9 disposed on the rear side. The front frame body 8 has a pair of left and right main frame members 20L and 20R, a pair of left and right subframe members 21L and 21R, and a pair of left and right lower frame members (bracket members) 22L and 22R. The rear frame body 9 has a pair of left and right rear frame members 23L and 23R and a pair of left and right rear auxiliary frame members 24L and 24R. The front and rear frame bodies 8, 9 include a plurality of cross members 26, 27, 30, 35, 42 and a plurality of connection frame members 28, 29, 46 in addition to the above. Each frame member is formed of a circular or square pipe material.

  The left and right main frame members 20 </ b> L and 20 </ b> R have a front end portion coupled to the head pipe 25 and a rear end portion coupled to the central cross member 26. As shown in FIGS. 1 and 2, the left and right main frame members 20 </ b> L and 20 </ b> R have a front side inclined slightly forwardly downwardly and a rear side inclined rearwardly downwardly as viewed from the side. In FIG. 1, α1 is given to the inclination angle with respect to the horizontal line on the rear side.

  FIG. 4 is a plan view of the front side of the vehicle body frame. The left and right main frame members 20L and 20R are inclined so as to move away from the vehicle width center O1 as the front side moves rearward as viewed from above, and the rear side is rearward. The vehicle is inclined to approach the vehicle width center O1 as it goes. The front and rear substantially central portions of the main frame members 20L and 20R protrude most outward in the left-right direction (vehicle width direction). The front portions of the left and right main frame members 20 are connected to each other by a front cross member 27 extending in the left-right direction. The front cross member 27 is connected to the head pipe 25 via a connection frame member 28 at the left and right central portions. Each of the left and right main frame members 20 is connected to the head pipe 25 by a connecting frame member 29 extending obliquely at the front side of the front cross member 27.

  As shown in FIG. 3, the left and right subframe members 21L and 21R are disposed below the left and right main frame members 20L and 20R, respectively, and are formed in an L shape in a side view. Each sub-frame member 21L, 21R extends downward from the front lower surface of the main frame member 20L, 20R and bends backward at the lowest end, and the rear end portion is coupled to the central cross member 26.

  As shown in FIGS. 1 and 2, the lower frame members 22L and 22R are disposed on the lower side of the central cross member 26, and are formed in a C-shape or a U-shape when viewed from the side with the upper and lower ends facing forward. Has been. The left lower frame member 22L has an upper end coupled to the lower surface of the central cross member 26 (FIG. 2), and the right lower frame member 22R is coupled to the lower surface of the rear end of the right subframe member 21R (FIG. 2). 1). The lower ends of the left and right lower frame members 22L and 22R are connected to each other by a lower cross member 30. A support bracket 33 including a boss portion 32 for supporting the front end of the swing arm 11 is provided on the front side of the left and right lower frames 22L and 22R. The left and right support brackets 33 and 33 are connected to each other by a left and right auxiliary cross member 35 disposed between the center cross member 26 and the boss portion 32.

  As shown in FIG. 1, engine mounting brackets 37, 38, and 39 are provided on the lower cross member 30, the auxiliary cross member 35, and the lower end portion of the subframe member 21. , 39, the engine 13 is supported by the vehicle body frame 10.

  As shown in FIG. 3, the left and right rear frame members 23L and 23R function as seat rails for supporting a seat (not shown), and the front ends are coupled to the rear portions of the left and right main frame members 20L and 20R, respectively. The rear end portions are connected to each other by the connecting bracket 41. The front and rear intermediate portions of the left and right rear frame members 23L and 23R are connected to each other by a rear cross member 42.

  The left and right rear auxiliary frame members 24L and 24R are disposed below the left and right rear frame members 23L and 23R, respectively. As shown in FIG. 2, the rear auxiliary frame member 24L on the left side has a rear end portion coupled to the rear portion of the rear frame member 23L and extends forward and in a slanting manner, and the front end is halfway up and down the left lower frame member 22L. Connected to the part. On the other hand, as shown in FIG. 1, the right rear auxiliary frame member 24R has a rear end portion coupled to the rear portion of the rear frame member 23R and forwardly inclined downward, and a front end coupled to the auxiliary cross member 35. Has been.

  FIG. 5 is a plan view of the front-rear center portion of the vehicle body frame 10, and the right rear auxiliary frame member 24 </ b> R includes a front member 44 and a rear member 45. The rear member 45 is formed in a substantially L shape in plan view by a portion 45a extending in the front-rear direction and a portion 45b extending leftward from the front end of the front-rear portion 45a. The rear end portion of the front-rear direction portion 45a is coupled to the rear portion of the right rear frame member 23R, and the left-right direction portion 45b is disposed near the center in the front-rear direction of the rear frame member 23 (below the rear cross member 42). Is coupled to the left rear auxiliary frame member 24L. The front member 44 extends in the front-rear direction, the rear end portion is coupled to the left-right direction portion 45 b of the rear member 45, and the front end is coupled to the auxiliary cross member 35. Further, the front member 44 and the right rear frame member 23R are connected by a connection frame member 46 extending in the vertical direction and the horizontal direction. The connection frame member 46 is substantially perpendicular to the front member 44 when viewed from the side. Reinforcing gussets (ribs) 76 are provided at the connecting portion between the left and right direction portion 45b of the rear member 45 and the left rear auxiliary frame member 24L, and the reinforcing gusset (at the connecting portion between the left and right direction portion 45b and the front member 44 is provided. Rib) 77 is provided.

  Accordingly, the left and right rear auxiliary frame members 24L and 24R are asymmetrical to each other, and the right rear auxiliary frame member 24R is displaced closer to the vehicle width center O1 than the left rear auxiliary frame member 24L. A displacement portion (front member) 44 is provided, and a space S is formed below the right rear frame member 23R and outside the displacement portion 44 in the left-right direction. In this space S, the rear suspension 12 is arranged.

[Configuration of swing arm]
FIG. 6 is a plan view of the swing arm 11. The swing arm 11 includes an arm main body 51, left and right stabilizer members 52L and 52R provided on the upper surface of the arm main body 51, a pivot cylinder 53 provided at the front end of the arm main body 51, and the like.

  The arm body 51 includes a pair of left and right arm members 55L and 55R extending in the front-rear direction, and a cross member 56 that interconnects the front and rear intermediate portions of the left and right arm members 55L and 55R. 55R is arranged at intervals in the vehicle width direction, and a rear axle (not shown) is supported at the rear ends of both arm members 55L, 55R.

  The left and right stabilizer members 52L and 52R are provided substantially along the left and right arm members 55L and 55R as viewed from above. As shown in FIG. 2, the left stabilizer member 52L has a rear end coupled to the upper surface of the rear portion of the left arm member 55L, a front end coupled to the pivot cylinder 53, and a front and rear middle portion bent upward in a mountain shape. Has been. The bent portion of the left stabilizer member 52L is connected to the cross member 56 via a support member 58 extending vertically.

  As shown in FIG. 1, the right stabilizer member 52 </ b> R has a rear end coupled to the rear upper surface of the right arm member 55 </ b> R and extends obliquely forward and upward. The front end portion of the right stabilizer member is connected to the cross member 56 via a support member 59 extending vertically. As shown in FIG. 6, the right support member 59 and the left support member 58 are connected by a reinforcing member 60 extending in the left-right direction.

  FIG. 7 shows the cross-sectional shapes of the left and right stabilizer members 52L and 52R. The left stabilizer member 52L is formed of a pipe material having a circular (true circular) cross section, whereas the right stabilizer member 52R is The pipe material has an elliptical cross section that is long in the vertical direction. The left and right stabilizer members 52L and 52R have substantially the same left-right width, or the right stabilizer member 52R is formed slightly smaller, and the upper and lower lengths of the right stabilizer member 52R are longer. The thickness of the pipe material of both the stabilizer members 52L and 52R is substantially the same. Therefore, the strength (rigidity) of the right stabilizer member 52R is higher than that of the left stabilizer member 52L, and in particular, the bending strength (bending rigidity) in the vertical direction is higher.

  FIG. 8 is an exploded perspective view showing a connecting portion between the vehicle body frame 10 and the swing arm 11. The swing arm 11 is swingably supported by the lower frame members 22L and 22R by inserting the pivot cylinder 53 between the boss portions 32 of the left and right support brackets 33 and inserting the pivot shaft 57 from the side.

[Rear suspension and its mounting structure]
The rear suspension 12 is, for example, a shock absorber in which a hydraulic shock absorber 12a and a shock absorbing coil spring 12b are combined, and can extend and contract in the longitudinal direction. As shown in FIG. 1, the central cross member 26 is provided with a front support boss 63 for attaching the front end portion of the rear suspension, and after the rear end portion of the rear suspension 12 is attached to the front end portion of the right stabilizer member 52R. A support boss 64 is provided.

  9 is a front sectional view of the front support boss 63, and FIG. 10 is a sectional view taken along the line XX of FIG. The central cross member 26 includes a cylindrical body (main body portion) 26A extending in the left-right direction, and a front support boss 63 fixed to the right end of the cylindrical body 26A by welding or the like. The front support boss 63 includes a pair of left and right shaft support plates (shaft support portions) 65 and 65, and a connection plate (connection portion) 66 that connects the shaft support plates 65 and 65 at the outer peripheral portion. 65 and the connecting plate 66 are fixed by welding or the like.

  The shaft support plate 65 has a dish shape, and a shaft through hole 67 is formed at the center, and a nut member 69 is fixed to the side surface of the shaft support plate 65 on the cylindrical body 26A side coaxially with the shaft through hole 67. .

  The connecting plate 66 is formed in a C shape in a side view, and an opening 68 into which the front end portion of the rear suspension 12 can be inserted is formed between the pair of support plates 65 and 65. The connecting plate 66 is provided in a range extending over more than half of the outer periphery of the shaft support plate 65 so that the opening 68 is formed in a substantially minimum size into which the front end portion of the rear suspension 12 can be inserted. The rear end portion of the right main frame member 20R and the rear end portion of the right subframe 21R abut against the connecting plate 66 and are fixed by welding.

  As shown in FIGS. 8 and 9, the front end portion of the rear suspension 12 is inserted into the front support boss 63 through the opening 68, and the shaft bolt 70 is inserted into the shaft through hole 67 from the left and right outside of the front support boss 63. By being screwed into the nut member 69, the front support boss 63 is swingably attached. The front end swing fulcrum P of the rear suspension 12 is disposed on the axis O2 of the central cross member 26, and as shown in FIG. 10, the right main frame member 20R and the right subframe member 21R are seen from the side. It arrange | positions in the position which cross | intersects center axis line O3 and O4.

  As shown in FIGS. 6 and 8, the rear support boss 64 is configured by a U-shaped plate material in a plan view provided at the front end of the right stabilizer member 52 </ b> R. A shaft through hole 71 is formed on both left and right sides of the rear support boss 64. The rear end portion of the rear suspension 12 is inserted into a U-shape of the rear support boss 64, and a shaft bolt 72 is inserted into the shaft through hole 71 and fastened with a nut 73, so that the rear suspension 12 can swing on the rear support boss 64. Attached to.

  As shown in FIG. 5, the rear suspension 12 attached as described above is displaced from the vehicle width center O1 to the right side and is arranged in parallel with the vehicle width center O1, and the amount of displacement is the rear of the right main frame member 20R. It matches the amount of displacement at the end. As shown in FIG. 1, the rear suspension 12 is arranged in a downwardly inclined manner when viewed from the side, and the inclination angle α2 with respect to the horizontal line substantially coincides with the inclination angle α1 of the main frame member. Therefore, the right main frame member 20R and the rear suspension 12 are arranged on substantially the same straight line when viewed from the side.

  Further, as shown in FIG. 5, the rear suspension 12 is disposed in a space S formed on the left and right outer sides of the displacement portion 44 of the right rear auxiliary frame member 24R, and the right suspension frame member 23R of the right rear frame member 23R is viewed from above. It is arranged so as to overlap the lower side. Further, as shown in FIG. 1, the rear suspension 12 is disposed so as to intersect the displacement portion 44 of the right rear auxiliary frame member 24 </ b> R when viewed from the side.

  In FIG. 1, the right stabilizer member 52R of the swing arm 11 is arranged in a downwardly inclined manner when viewed from the side, and the inclination angle α3 with respect to the horizontal line is substantially the same as or close to the inclination angles α1 and α2. ing. Further, since the rear end of the rear suspension 12 is attached to the front end portion of the right stabilizer member 52R, the rear suspension 12 and the right stabilizer member 52R are disposed on substantially the same straight line when viewed from the side and from above.

[Effects of this embodiment]
(1) As shown in FIG. 1, when the swing arm 11 swings up and down relative to the vehicle body frame 10 during traveling, the rising load is transmitted from the right stabilizer member 52 </ b> R to the rear suspension 12. Attenuated and transmitted to the right main frame member 20R. At this time, the rear suspension 12 is connected to the rear end portion of the right main frame member 20R so as to be continuous, and the rear suspension 12 and the right main frame member 20R are arranged on the same straight line when viewed from the side. Therefore, the vehicle body frame 10 can receive the load from the rear suspension 12 as the axial load of the right main frame member 20R, and little lateral load is applied, so that the thickness of the vehicle body frame 10 and the pipe diameter are increased. The load from the swing arm 11 can be received.

(2) Since the front end swing fulcrum P of the rear suspension 12 is disposed on the axis O2 of the central cross member 26 as shown in FIG. 10, the center due to the load transmitted from the rear suspension 12 No torsional moment is generated in the cross member 26. Therefore, the burden on the central cross member 26 can be reduced, and the weight of the cross member can be reduced. Further, since the swing fulcrum P does not protrude forward and backward and up and down from the central cross member 26, the appearance seen from the side is also improved.

(3) As shown in FIG. 5, a part (displacement part) 44 of the right rear auxiliary frame member 24R is arranged near the vehicle width center O1, and the arrangement space S of the rear suspension 12 on the left and right outer sides of the displacement part 44. Therefore, the rear suspension 12 can be arranged so as to overlap the lower side of the right rear frame member 23R without overhanging in the vehicle width direction. Therefore, the maintenance and inspection of the rear suspension 12 from the outside can be easily performed, the appearance is improved, and the rear suspension 12 does not interfere with the legs of the rider or passenger.

(4) As shown in FIGS. 1 and 5, the displacement portion 44 of the right rear auxiliary frame member 24R and the right rear frame member 23R are coupled by the connecting frame member 46, and both are reinforced, so that the displacement Although the portion 44 is disposed closer to the vehicle width center O1, the rigidity of the rear frame body 9 can be maintained, and in particular, the left and right torsional rigidity of the rear frame member 23 can be maintained.

  This point will be described in detail. The rear auxiliary frame members 24L and 24R mainly reinforce the load from above on the rear frame members 23L and 23R. In the present embodiment, as shown in FIG. The sandwiching angle β2 between the right rear frame member 23R and the right rear auxiliary frame member 24R is smaller than the sandwiching angle β1 between the left rear frame member 23L and the left rear auxiliary frame member 24L, and the right rear portion Since the displacement portion 44 is displaced in the left-right direction with respect to the frame member 23R, the right rear auxiliary frame member 24R alone is inferior in function of the reinforcement as compared with the left side. Therefore, in the present embodiment, the reinforcing function is supplemented by connecting the displacement portion 44 and the right rear frame member 23R by the connection frame member 46.

(5) As shown in FIG. 5, the right rear auxiliary frame member 24 </ b> R is configured by a combination of a linear front member 44 and an L-shaped rear member 45. Can be manufactured at a low cost. In addition, a cross member (45b) for connecting the left and right rear auxiliary frame members 24L and 24R to each other can be formed at the same time.

(6) As shown in FIG. 9, in the front support boss 63 that supports the front end portion of the rear suspension 12, the thickness of the connecting plate 66 is larger than the thickness of the cylindrical body 26 </ b> A of the central cross member 26. Therefore, in the central cross member 26, the strength of the portion to which the right main frame member 20R is coupled can be partially increased, and an increase in the weight of the entire central cross member 26 can be suppressed.

(7) Since the front support boss 63 is formed in a cylindrical shape like the cylindrical body 26A of the central cross member 26, the cylindrical body 26A and the front support boss 63 are integrated with each other without a sense of incongruity when viewed from the outside. And the appearance is improved.

(8) The stabilizer members 52L and 52R of the swing arm 11 have an oval cross section on the right side 52R to which the rear suspension 12 is attached, a true circle on the left side 52L, and the strength and rigidity of the right side 52R are higher than those on the left side 52L. ing. That is, since the left and right stabilizer members 52L and 52R are configured to be asymmetric with each other by the deformed members, it is possible to increase the rigidity of only one (right side) and to withstand the reaction force received from the rear suspension. The rear suspension can be displaced left and right while suppressing the increase in weight of the entire swing arm 11 as much as possible.

(9) The right stabilizer member 52R has an oblong shape that is long in the vertical direction, and has increased rigidity without increasing the left-right width. Therefore, the arrangement of peripheral parts (brake-related parts, etc.) arranged on the side of the swing arm It rarely erodes space.

[Other Embodiments]
(1) The vehicle body frame 10 and the swing arm 11 can be reversed left and right across the vehicle width center O1, and in this case, the rear suspension 12 can be displaced leftward.

  (2) The rear auxiliary frame members 24L and 24R can be configured as shown in FIG. That is, the front-rear direction portion 45a of the rear member 45 of the right rear auxiliary frame member 24R and the front member 44 are formed of a single pipe material, and the intermediate portion between the front member 44 and the rear member 45 is formed by the cross member 75 to the left rear portion. It can be connected to the auxiliary frame member 24L.

  (3) The front support boss 63 that supports the front end portion of the rear suspension 12 is formed by bending a plate material into a U-shape and coupled to the end portion of the cylindrical body 26A of the central cross member 26. Can do. Also in this case, the swing fulcrum P of the rear suspension 12 can be disposed on the axis O2 of the central cross member 26.

  (4) As a method of increasing the strength of the right stabilizer member 52R relative to the left stabilizer member 52L by making the left and right stabilizer members 52L, 52R asymmetric in cross section, both the stabilizer members 52L, 52R have a circular cross section, and the outside of the right stabilizer member 52R. The diameter can be made larger than that of the left stabilizer member 52L, or both can be made the same outer diameter as shown in FIG. 12, and the thickness of the right stabilizer member 52R can be made thicker than that of the left stabilizer member 52L.

  The present invention can be applied to various motorcycles such as motorcycles for general use or racing.

1 is a right side view of a body frame or the like of a motorcycle according to an embodiment of the present invention. Fig. 2 is a left side view of a body frame and the like of the same motorcycle. It is a perspective view of a body frame. It is a top view of the vehicle body frame front side. It is a top view of the front-back center part of a vehicle body frame. It is a top view of a swing arm. It is sectional drawing which shows the shape of each stabilizer member on either side. It is a disassembled perspective view which shows the connection part of a vehicle body frame and a swing arm. It is sectional drawing which shows the front support boss | hub part of a rear suspension. It is XX arrow sectional drawing of FIG. It is a top view of the front-back center part of the vehicle body frame concerning other embodiment. It is sectional drawing which shows the shape of each left-right stabilizer member which concerns on other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Body frame 11 Swing arm 12 Rear suspension 15 Rear wheel 26 Center cross member 63 Front support boss 65 Support plate material 66 Connection plate material

Claims (3)

A motorcycle having a body frame and a rear wheel swing arm supported by the body frame so as to be swingable up and down, and having a rear suspension interposed between the body frame and the rear wheel swing arm. In the body structure,
The vehicle body frame has a pair of left and right main frame members extending rearward from the head pipe, and a cross member connecting between the rear end portions of the main frame members,
The cross member has a support boss that swingably supports an end of the rear suspension at a connection portion with the main frame member;
A swing fulcrum of the rear suspension in the support boss is disposed substantially coaxially with the cross member,
A vehicle body structure for a motorcycle, wherein the swing fulcrum is arranged so as to intersect with a central axis of a rear end portion of an adjacent main frame member . A motorcycle having a body frame and a rear wheel swing arm supported by the body frame so as to be swingable up and down, and having a rear suspension interposed between the body frame and the rear wheel swing arm. In the body structure,
The vehicle body frame has a pair of left and right main frame members extending rearward from the head pipe, and a cross member connecting between the rear end portions of the main frame members,
The cross member has a support boss that swingably supports an end of the rear suspension at a connection portion with the main frame member;
A swing fulcrum of the rear suspension in the support boss is disposed substantially coaxially with the cross member,
2. A vehicle body structure for a motorcycle, wherein the rear suspension is disposed substantially on the same straight line as the main frame member when viewed from the side. The cross member has a main body portion extending in the left-right direction, and the support boss fixed to an end portion of the main body portion,
The support boss, a pair of shaft support portions for supporting both ends of the swing shaft of the rear suspension, as well as connected to each other with the hinge supporting portion, connecting portion connected to the rear end portion of the main frame member The vehicle body structure of a motorcycle according to claim 1 or 2, characterized by comprising:

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