JP4620539B2 - Motorcycle frame structure - Google Patents

Description

  The present invention relates to an improvement in the frame structure of a motorcycle.

As a conventional motorcycle frame structure, there is known a structure in which a pivot plate is attached to a rear portion of a main frame, and a pivot shaft is attached to the pivot plate (for example, see Patent Document 1).
Japanese Patent No. 3548173

  2 and 5 of Patent Document 1, a pivot plate 17 is attached to the rear portion of the main frame 13 constituting the vehicle body frame, a support shaft 20 is attached to the pivot plate 17, and a rear wheel is supported on the support shaft 20. It is described that the rear fork 21 to be mounted is swingable up and down.

  The pivot plate 17 includes left and right flat plate portions 18 and 18 and a connecting plate portion 19 that connects these flat plate portions 18 and 18, and is attached by penetrating a support shaft 20 to the left and right flat plate portions 18 and 18. is there.

The left and right flat plate portions 18, 18 of the pivot plate 17 need a large width to penetrate the support shaft 20, and the longitudinal length of the flat plate portions 18, 18 increases, so that the pivot plate 17 becomes large.
Further, the pivot plate 17 is required to be further improved in rigidity because a large load is applied to support the rear wheel via the rear fork 21.

  An object of the present invention is to improve the frame structure of a motorcycle to reduce the size and rigidity of the pivot plate.

According to a first aspect of the present invention, there is provided a main frame extending obliquely downward and rearward from the head pipe, a rear frame coupled to a rear portion of the main frame and extending obliquely rearward and upward, and an engine unit supported by a lower portion of the main frame. In this motorcycle, a pivot pipe is provided on the back of a pivot plate provided at the lower rear part of the main frame, and the rear fork is swingably supported by the pivot pipe. The pivot plate has a pair of opposed flat plate portions and these It has a connecting plate that connects the rear end of the flat plate part and has a substantially U-shaped cross section that opens to the front, and a notch is provided on the back of the connecting plate, and a pivot pipe is fitted into this notch It was made to be characterized.

Since the pivot pipe is provided on the back surface of the pivot plate, the front and rear width of the pivot plate is shorter than the conventional case where the pivot pipe is passed through the left and right pivot plates. In addition, the pivot pipe can be supported by the entire back surface of the pivot plate, so that the pivot pipe is firmly supported and the rigidity of the pivot plate itself is improved.
Further, by fitting the pivot pipe into the notch provided on the back surface of the connecting plate, the longitudinal length of the pivot plate to which the pivot pipe is attached can be further reduced. Further, the fitting of the pivot pipe to the notch strengthens the connection between the pivot plate and the pivot pipe and improves the rigidity of the pivot plate.

According to a second aspect of the present invention, intermediate portions of a pair of connecting members that are arranged on both sides of the main frame and connect the rear frame and the pivot plate are connected to the main frame, and the front ends of these connecting members are connected to the pivot plate. It is connected to at least a pivot pipe provided on the back surface.

  Since the pivot pipe is supported by the connecting member connected to the main frame in addition to the support by the main frame, the rigidity of the pivot portion including the pivot plate and the pivot pipe is further improved.

The invention according to claim 3 is characterized in that the muffler is supported on the lower back surface of the pivot plate.
Since the lower rear surface of the pivot plate is close to the center of the vehicle body and close to the muffler, the stay that supports the muffler is downsized.

The invention according to claim 4 is characterized in that the pillion step bracket for supporting the pillion step on which the passenger puts his / her foot is supported by the pivot pipe and the rear frame.
Since the pillion step bracket is supported by the pivot pipe and the rear frame, the pillion step bracket is more reliably supported.

In the invention according to claim 1, since the pivot pipe is provided on the back surface of the pivot plate, and the rear fork is swingably supported by the pivot pipe, the front and rear width of the pivot plate can be shortened, and the pivot plate can be reduced in size. be able to. In addition, the pivot pipe can be supported by the entire back surface of the pivot plate, whereby the pivot pipe can be firmly supported and the rigidity of the pivot plate itself can be improved.
Further, in the present invention, the pivot plate has a substantially U-shaped cross-sectional shape opened forward by including a pair of opposed flat plate portions and a connecting plate connecting the rear ends of these flat plate portions, A notch is provided on the back of the plate, and the pivot pipe is fitted into this notch, so the front and rear length of the pivot plate to which the pivot pipe is attached can be reduced, and the pivot part consisting of the pivot plate and the pivot pipe can be made compact. Can be.
Furthermore, by fitting the pivot pipe into the notch, the coupling between the pivot plate and the pivot pipe can be strengthened and the rigidity of the pivot plate can be improved.

In the invention according to claim 2, the middle part of the pair of connecting members that are arranged on both sides of the main frame and connect the rear frame and the pivot plate are connected to the main frame, and the front ends of these connecting members are connected to the pivot plate. Since the pivot pipe is connected to at least the pivot pipe provided on the back surface, the pivot pipe is supported by the coupling member connected to the main frame in addition to the support by the main frame, so that the rigidity of the pivot portion including the pivot plate and the pivot pipe is further increased. Can be improved.

In the invention according to claim 3, since the muffler is supported by the lower rear surface of the pivot plate, the lower rear surface of the pivot plate and the muffler come close to each other, and the stay that supports the muffler can be reduced in size.

In the invention according to claim 4, since the pillion step bracket is supported by the pivot pipe and the rear frame, the pillion step can be supported more reliably.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a side view of a motorcycle having a frame structure according to the present invention. The motorcycle 10 includes a main frame 12 extending rearward and obliquely downward from a head pipe 11 and a rear end of the main frame 12. A pair of left and right rear frames 21, 22 (supporting an engine unit 18 including an engine 16 and a transmission 17, and extending obliquely rearward and upward from a rear portion of the main frame 12). This is a vehicle in which a fuel tank 23 is attached to the front side, and a storage box 24 is attached to the fuel tank 23 and the rear frames 21 and 22, and a tandem seat 26 is attached to the storage box 24 so as to be openable and closable. is there.

The head pipe 11 is a member on which a front fork 31 that supports the front wheel 28 at the lower end is attached so as to be steerable.
The pivot plate 13 and the rear frames 21 and 22 span a pair of left and right subframes 34 and 34 (only the front side reference numeral 34 is shown), and a pair of left and right pillion steps 36 and 37 (front side) for passengers. A pair of left and right step support frames 41 and 42 for supporting each of them are attached.

The head pipe 11, the main frame 12, the pivot plate 13, the rear frames 21 and 22, and the sub frames 34 and 34 are members constituting the vehicle body frame 45.
The pivot plate 13 is a member in which a rear fork 47 that supports the rear wheel 46 at the rear end is swingably attached via a pivot pipe described later.

The engine 16 is provided with a substantially horizontal cylinder portion 50 at the front, and an intake device 52 and an exhaust device 53 are connected to a cylinder head 51 provided in the cylinder portion 50.
The intake device 52 includes an air cleaner 55 attached to the front portion of the main frame 12, and an injector integrated throttle body 57 having one end connected to the air cleaner 55 and the other end connected to the cylinder head 51 via an intake pipe 56. Prepare.

The exhaust device 53 includes an exhaust pipe 61 having one end connected to the cylinder head 51, a catalyst 62 provided in the middle of the exhaust pipe 61, and a muffler 63 connected to the rear end of the exhaust pipe 51. It is arranged behind the engine unit 18.
The catalyst 62 has a higher ground clearance by being disposed in a space 64 formed below the cylinder portion 50 and in front of a crankcase 65 described later.

  The engine unit 18 includes a crankcase 65, and is attached to a lower portion of the crankcase 65, and main steps 66 and 66 (only the reference numeral 66 on the front side is shown) for a driver extending on both sides are arranged. A rear wheel brake pedal 67 and a main stand 68 are swingably supported at the lower rear end of the crankcase 65.

  Here, 71 is a handle cover, 72 is a front cover, 73 is a battery disposed in front of the head pipe 11, 73a is a battery support bracket attached to the front of the head pipe 11 to support the battery 73, and 74 is a front wheel. Front fender covering the upper and rear of 28, 76 is a leg shield, 77 is opened and closed when fueling from a fuel filler port 23e (see FIG. 3, 78 is a cap for closing the fuel filler port) provided in the fuel tank 23. A refueling lid with a locking device provided on the leg shield 76, 81 and 81 (only the front side reference numeral 81 is shown) is a pair of left and right engine hangers attached to the main frame 12, and 82 is attached to the rear wheel axle 83. A drum brake device 84 is provided to prevent the drum brake device 82 from rotating. A torque rod passed between the rear fork 47 and the rear fork 47, 86 a rear cushion unit 47 a provided on the rear fork 47 and one rear frame 21 side, and 87 a rear portion of the storage box 24. A mudguard attached to the lower part, 88 is a rear fender that covers the rear wheel 46, 91 is a grab rail, and 92 is a tail lamp.

  FIG. 2 is a plan view of an essential part of the motorcycle according to the present invention (the arrow (FRONT in the figure indicates the front of the vehicle; the same applies hereinafter)), and the exhaust pipe 61 extends downward and rearward from the cylinder head 51 of the engine 16. The muffler 63 is connected to the rear end of the exhaust pipe 61 in the vicinity of the rear end of the crankcase 65 of the engine unit 18, and the pair of left and right are integrally formed with the rear end of the crankcase 65. Stand support bosses 65S, 65S are provided, shaft support holes 65a, 65b are formed in the stand support bosses 65S, 65S, and the support shaft 101 is passed through the shaft support holes 65a, 65b. It shows that the pedal 67 and the main stand 68 are supported in a swingable manner.

  The exhaust pipe 61 extends substantially linearly in the vehicle front-rear direction below the engine unit 18, and the catalyst 62 extends in the vehicle front-rear direction and substantially overlaps the cylinder portion 50 of the engine 16 in a plan view. It is located in front of the vehicle with respect to the protruding portion 65c and the right bulging portion 65d.

  The muffler 63 includes a wide front portion 63a disposed between the engine unit 18 and the rear wheel 46, and a vertically long rear portion 63b extending rearward from the wide front portion 63a along the right side surface of the rear wheel 46. It has a letter shape. Reference numeral 69 denotes a tail pipe provided at the rear end of the vertically long rear portion 63b.

  The muffler 63 is disposed below the rear fork 47, and the tail pipe 69 of the muffler 63 is provided on the left and right pillion steps 36, 37 below the rear fork 47, specifically, the arm 104 on the right side of the rear fork 47. It is arranged inside. For this reason, the muffler 63 can be made difficult to be exposed to the outside.

The wide front part 63a is provided with a left part attaching part 63c attached to the back surface of the pivot plate 13 (see FIG. 1), and the vertically long rear part 63b is provided with a right part attaching part 63d attached to one step support frame 42.
The torque rod 84 has a front end attached to a cross member 105 that connects the left and right arm portions 103 and 104 of the rear fork 47.

Here, 111 is a mounting bracket for attaching the leg shield 76 to the cylinder portion 50, 112 is a change pedal provided in the transmission 17, 113 is a side stand, and 114 is a pivot plate 13 (see FIG. 1) for supporting the rear fork 47. An attached pivot pipe, 116 is a kick pedal for starting the engine, and 117 is a step bar attached to the crankcase 65 side in order to connect the left and right main steps 66, 66.
The pivot pipe 114 described above supports the left and right step support frames 41 and 42 together with the rear fork 47.

  FIG. 3 is a side view of the main part of the motorcycle according to the present invention. The fuel tank 23 has a flange 23a attached to the left and right rear frames 21, 22 (only the reference numeral 21 on the front side is shown). The mounting brackets 121 and 122 are attached with bolts 123 and nuts 124 (the nuts 124 are fixed to the lower surfaces of the tank mounting brackets 121 and 122). A fuel pump 125 is disposed in the fuel tank 23 and attached to the upper wall of the fuel tank 23.

  The tank mounting brackets 121 and 122 are members attached before and after the bent portions 21b and 22b (only the front side 21b is shown) of the rear frames 21 and 22, and the fuel tank 23 includes the bent portions 21b and 22b. Therefore, the fuel tank 23 can serve as a reinforcing material for the rear frames 21 and 22, and the rigidity of the rear frames 21 and 22 can be improved. Further, since the fuel tank 23 is provided to the left and right rear frames 21 and 22, and also serves as a cross member of the vehicle body frame 45, it can greatly contribute to the improvement of the overall rigidity of the vehicle body frame 45.

  The rear end portion 12a of the main frame 12 is a portion that is reduced to a height H2 with respect to the height H1 on the front side by crushing up and down, thereby lowering the position of the bottom surface 23f of the fuel tank 23, The capacity of the fuel tank 23 was expanded.

  The storage box 24 has a pair of left and right front lower protrusions 24a and 24a (only the front side reference 24a is shown) and a pair of left and right rear lower protrusions 24b and 24b (only the front side 24b is shown) on the bottom. The front lower protrusions 24a and 24a are attached to a pair of left and right box mounting brackets 126 and 126 (only the reference numeral 126 on the front side) attached to the upper surface of the fuel tank 23 with a bolt 128 and a nut member 131, and the rear part. The downward projecting portions 24b and 24b are attached to box mounting brackets 127 attached to the rear frames 21 and 22 with bolts 128 and nut members 131, respectively.

  The nut member 131 is a cylindrical member having a flange at one end. The nut member 131 is provided with a female screw on the inner surface of the cylinder. The nut member 131 is passed through the insertion holes formed in the box mounting brackets 126 and 127 from the bottom to the box mounting brackets 126 and 127. It is fixed by welding.

  The storage box 24 is attached to the box mounting brackets 126 and 127 at the portions of the nut member 131 that protrude upward from the box mounting brackets 126 and 127, at the front lower protrusions 24 a and 24 a and the rear lower protrusions of the storage box 24. Positioning is performed by fitting through holes opened in 24 b and 24 b and screwing the bolts 128 into the female screws of the nut member 131 from within the storage box 24.

The muffler 63 is a container having a lower muffler half 135 connected to the exhaust pipe 61 and an upper muffler half 136 aligned vertically.
The lower muffler half body 135 includes a lower bulging portion 135a that bulges downward to a position where the bottom surface of the lower muffler half body 135 overlaps the main stand 68 in a state of being flipped up.

  The left mounting portion 63c, which is the mounting portion of the muffler 63 to the pivot plate 13, is composed of a mounting bracket 137 mounted on the upper muffler half 136 and a nut (not shown) mounted on the side surface of the mounting bracket 137. 138 is passed through a stay 139 attached to the back surface of the pivot plate 13 and screwed into a nut (not shown) on the mounting bracket 137 side described above, so that the left attachment portion 63c is attached to the pivot plate 13.

  The right mounting portion 63d, which is the mounting portion of the muffler 63 to the step support frame 42, includes a mounting bracket 141 mounted on the upper muffler half 136 and a cylindrical member 142 mounted on the upper portion of the mounting bracket 141. By attaching the cylindrical member 142 to the bracket 144 provided on the step support frame 42 with bolts 146 and nuts 147, the right attachment portion 63 d is attached to the step support frame 42.

  The step support frames 41 and 42 are respectively attached to the pivot pipe 114 provided at the lower portion thereof on the pivot plate 13 with the bolts 151 coaxially with the rear fork 47, and brackets 152 and 152 provided on the rear frames 21 and 22 at the upper portion (front side). These are attached with bolts 153 respectively.

  4 is a side view of the main part of the vehicle body frame according to the present invention. The rear frames 21 and 22 are welded to the left and right rear portions of the main frame 12, and the pivot plate 13 is welded to the lower portion of the rear end of the main frame 12. The pivot pipe 114 is fitted and welded to a notch 13b provided on the rear surface 13a of the pivot plate 13, and the subframes 34 and 34 (reference numerals 34 on the front side) are attached to the rear surface 13a of the pivot plate 13 and the outer peripheral surface 114a of the pivot pipe 114. Only one end) is welded. Reference numeral 139 denotes a stay attached to the lower portion of the back surface 13a of the pivot plate 13.

  The sub-frames 34 and 34 are members having intermediate portions attached to both side surfaces 12c and 12c of the main frame 12 (only the front side reference numeral 12c is shown) by welding. Reference numeral 161 denotes a reinforcement pipe that is passed to the left and right subframes 34 and 34 for reinforcement.

5 (a) and 5 (b) are explanatory views showing the pivot portion according to the present invention.
(A) is a perspective view of the main part of the vehicle body frame, and the pivot plate 13 includes a pair of flat plate portions 13D and 13E (only one symbol 13D is shown) provided on the left and right sides, and these flat plate portions 13D and 13E. It is a member having a substantially U-shaped cross-sectional shape opened forward by an integrally formed product comprising a connecting plate 13F for connecting the rear ends.

The pivot pipe 114 is attached to the notch 13b (see FIG. 4) on the connecting plate 13F side, and the stay 139 is attached to the back surface 13a of the connecting plate 13F.
The stay 139 is an L-shaped plate, and is a member having a bolt insertion hole 139a and a nut 163 attached thereto.

  (B) is a perspective view of the pivot plate 13, and the notch 13b of the pivot plate 13 has an arcuate shape formed in a window portion 13h provided in an intermediate portion of the connecting plate 13F and the rear portions of the left and right flat plate portions 13D and 13E. And rear notch portions 13j and 13k. Reference numerals 13m and 13n denote an upper side and a lower side of the window portion 13h.

  In order to fit the pivot pipe 114 (see (a)) into the notch 13b, one end of the pivot pipe 114 is inserted, for example, from one rear notch 13j, and is inserted into the upper side 13m and the lower side 13n of the window portion 13h. It is made to move along and it protrudes from the other rear notch part 13k, or the outer peripheral surface of the intermediate part of the pivot pipe 114 is inserted into the window part 13h, and it moves to the back of the rear notch parts 13j and 13k. Thereafter, the pivot pipe 114 is joined to the pivot plate 13 by welding.

  Since the welding of the pivot plate 13 and the pivot pipe 114 is performed at the upper side 13m and the lower side 13n of the window portion 13h, the rear notches 13j and 13k, and the outer peripheral surface 114a of the pivot pipe 114 (see (a)), The welding length can be increased, the strength of the coupling between the pivot plate 13 and the pivot pipe 114 can be increased, and a firm coupling can be achieved.

Returning to FIG. 4, the pivot plate support structure for supporting the pivot plate 13 has a pivot plate 13 attached to the lower part of the rear end of the main frame 12, and a pivot pipe 114 attached to the rear surface 13 a of the pivot plate 13. And one end of each of the sub-frames 34 and 34 is attached to the pivot pipe 114, the other end of the sub-frames 34 and 34 is attached to the rear frames 21 and 22, and an intermediate portion of the sub-frames 34 and 34 is attached to the rear end portion of the main frame 12. In the side view, the main frame 12, the pivot plate 13, and the sub frame 34 form a triangle, and the main frame 12, the rear frames 21, 22 (only the reference numeral 21 on the front side is shown) and the sub. The frame 34 is a truss structure that forms a substantially triangular shape.
Accordingly, the rigidity of the pivot portion 165 including the pivot plate 13 and the pivot pipe 114 can be further improved.

  FIG. 6 is a view taken in the direction of arrow 6 in FIG. 3, and attaches intermediate portions of the subframes 34, 34 extending from the rear frames 21, 22 side to both side surfaces 12 c, 12 c of the main frame 12. It is shown that the ends are attached to the back surface 13a of the pivot plate 13 and the outer peripheral surface 114a of the pivot pipe 114.

  As described above, the pivot plate 13 attached to the main frame 12 and the pivot pipe 114 attached to the pivot plate 13 are also supported by the subframes 34 and 34 attached to the main frame 12, and therefore the rear fork 47 (see FIG. 1). The pivot plate 13 and the pivot pipe 114 to which a large load acts from the side can be firmly supported.

  7 is a cross-sectional view taken along line 7-7 of FIG. 4. The main frame 12 has a square pipe shape, and side covers (not shown) are attached to the engine hangers 81 and 81 attached to both side surfaces 12c and 12c of the main frame 12. FIG. It shows that the side cover stays 167 and 168 to be attached are attached. Reference numerals 167a and 168a denote bolt insertion holes through which bolts for mounting the engine are passed.

FIG. 8 is a side view of an essential part showing another embodiment of the pivot plate according to the present invention. In addition, about the same structure as embodiment shown in FIG. 4, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.
A pivot plate 171 attached to the rear lower portion of the main frame 12 is a connection for connecting a pair of left and right flat plate portions 172 and 172 (only the reference numeral 172 on the front side is shown) and the rear ends of these flat plate portions 172 and 172. This is a member formed integrally with the plate 173.

  The flat plate portion 172 includes an engine hanger portion 175 provided at the front portion, a pivot plate portion 176 provided at the rear portion, and a connecting portion 177 that connects each of the engine hanger portion 175 and the pivot plate portion 176.

  A notch 181 is provided at the rear portion of the pivot plate 171, and the pivot pipe 114 is fitted and welded to the notch 181, and the subframes 34, 34 are attached to the back surface 13 a of the connecting plate 173 and the outer peripheral surface 114 a of the pivot pipe 114. Each end of (only the front side code is shown) is attached by welding.

  As shown in FIGS. 1 and 4, the present invention firstly has a main frame 12 that extends rearward and obliquely downward from the head pipe 11, and is connected to a rear portion of the main frame 12 and extends obliquely upward and rearward. In the motorcycle 10 including the rear frames 21 and 22 and the engine unit 18 supported at the lower part of the main frame 12, a pivot pipe 114 is provided on the rear surface 13a of the pivot plate 13 provided at the lower rear part of the main frame 12. The rear fork 47 is swingably supported by the pivot pipe 114.

  Thereby, the front-rear width of the pivot plate 13 can be shortened, the pivot plate 13 can be reduced in size, and weight reduction and cost reduction can be achieved. Further, the pivot pipe 114 can be supported by the entire back surface 13a of the pivot plate 13, whereby the pivot pipe 114 can be firmly supported and the rigidity of the pivot plate 13 itself can be improved.

  Secondly, according to the present invention, as shown in FIGS. 5 and 6, the pivot plate 13 has a pair of opposing flat plate portions 13D and 13F and a connecting plate 13F connecting the rear ends of the flat plate portions 13D and 13E. And has a substantially U-shaped cross section opened forward, a notch 13b is provided on the back surface 13a of the connecting plate 13F, and a pivot pipe 114 is fitted into the notch 13b. To do.

  Accordingly, the longitudinal length of the pivot plate 13 to which the pivot pipe 114 is attached can be reduced, and the pivot portion 165 including the pivot plate 13 and the pivot pipe 114 can be reduced in size.

  Further, by fitting the pivot pipe 114 into the notch 13b, the connection between the pivot plate 13 and the pivot pipe 114 becomes strong and the rigidity of the pivot plate 13 can be improved.

  Thirdly, as shown in FIGS. 4 and 6, the present invention is arranged on both sides of the main frame 12 and a sub frame 34 as a pair of connecting members for connecting the rear frames 21 and 22 and the pivot plate 13. , 34 is connected to the main frame 12, and the front ends of these sub-frames 34, 34 are connected to at least the pivot pipe 114 provided on the back surface 13 a of the pivot plate 13.

  Since the pivot pipe 114 is supported by the subframes 34 and 34 connected to the main frame 12 in addition to the support by the main frame 12, the rigidity of the pivot portion 165 including the pivot plate 13 and the pivot pipe 114 is further improved. Can do.

Fourthly, the present invention is characterized in that the muffler 63 is supported by the back surface 13a of the lower portion of the pivot plate 13 via the stay 139 as shown in FIG.
Since the muffler 63 is supported by the lower back surface 13a of the pivot plate 13, the lower back surface 13a of the pivot plate 13 and the muffler 63, more specifically, the upper muffler half 136 approach each other, and the stay 139 that supports the muffler 63 is made compact. It is possible to reduce the weight.

The present invention fifthly, as shown in FIGS. 2 and 3, the step support frames 41 and 42 as the pillion step brackets for supporting the pillion steps 36 and 37 on which the passenger puts his / her foot, the pivot pipe 114 and the rear It is supported by the frames 21 and 22.
Since the step support frames 41 and 42 are supported by the pivot pipe 114 and the rear frames 21 and 22, the pillion steps 36 and 37 can be more reliably supported.

  In the present embodiment, as shown in FIG. 4, the end portions of the subframes 34 and 34 are coupled to the back surface 13a of the pivot plate 13 and the outer peripheral surface 114a of the pivot pipe 114. The ends of the sub-frames 34 and 34 may be coupled only to the outer peripheral surface 114a of 114.

  The frame structure of the present invention is suitable for a motorcycle.

1 is a side view of a motorcycle including a frame structure according to the present invention. 1 is a plan view of a main part of a motorcycle according to the present invention. 1 is a side view of a main part of a motorcycle according to the present invention. It is a principal part side view of the vehicle body frame which concerns on this invention. It is a principal part perspective view of the vehicle body frame which concerns on this invention. FIG. 6 is a view taken along arrow 6 in FIG. 3. FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 4. It is a principal part side view which shows another embodiment of the pivot plate which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Motorcycle, 11 ... Head pipe, 12 ... Main frame, 13 ... Pivot plate, 13a ... Back surface, 13b ... Notch, 13D, 13E ... Flat plate part, 13F ... Connecting plate, 18 ... Engine unit, 21, 22 ... Rear frame, 34: connecting member (subframe), 36, 37 ... pillion step, 41, 42 ... pillion step bracket (step support frame), 47 ... rear fork, 63 ... muffler, 114 ... pivot pipe, 165 ... pivot part .

Claims (4)

A main frame (12) extending obliquely rearward and downward from the head pipe (11), a rear frame (21, 22) coupled to a rear portion of the main frame (12) and extending obliquely rearward and upward, and the main frame (12 A motorcycle having an engine unit (18) supported at the lower part of
Wherein the rear of the pivot plate (13) provided in the rear lower portion of the main frame (12) provided with a pivot pipe (114), a rear fork (47) supported swingably by the pivot pipe (114),
The pivot plate (13) is provided with a pair of opposed flat plate portions (13D, 13E) and a connecting plate (13F) for connecting the rear ends of the flat plate portions (13D, 13E) and is almost open forward. It has a U-shaped cross-sectional shape,
Notches (13j, 13k) were provided on the back surface of the connecting plate (13F), and the pivot pipe (114) was fitted into the notches (13j, 13k).
A motorcycle frame structure characterized by that. An intermediate portion of a pair of connecting members (34, 34) arranged on both sides of the main frame (12) and connecting the rear frames (21, 22) and the pivot plate (13) is the main frame (12 The motorcycle according to claim 1 , wherein the front ends of the connecting members (34, 34) are connected to at least the pivot pipe (114) provided on the rear surface of the pivot plate (13). Frame structure. The frame structure of the motorcycle according to claim 1 or 2 , wherein the muffler (63) is supported by a lower back surface of the pivot plate (13) . A pillion step bracket (41, 42 ) for supporting a pillion step (36, 37) on which a passenger rests his / her foot is supported by the pivot pipe (114) and the rear frame (21, 22). The frame structure of the motorcycle according to any one of claims 1 to 3 .

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