JP2010023685A - Rear suspension structure of saddle-ride type vehicle - Google Patents

Abstract

In a rear suspension structure of a saddle-ride type vehicle provided with a swing arm type rear suspension, suspension parts are reduced in weight and simplified.
A pivot portion 60 for supporting a swing arm 11 is provided at a rear end portion of a crankcase 18 of an engine 16, and an under bracket 95 is attached below the pivot portion 60 in the crankcase 18. 95 is provided with a rear extending portion 95a extending rearward of the pivot portion 60 and in the vicinity of the swing arm 11, and a rear portion using a cushion rubber 104 between the rear extending portion 95a and the swing arm 11. A cushion 105 was provided.
[Selection] Figure 14

Description

  The present invention relates to a rear suspension structure suitable for a saddle-ride type vehicle such as a motorcycle.

2. Description of the Related Art Conventionally, there is a motorcycle rear suspension structure in which an integral swing unit that supports a rear wheel on an engine power system is elastically supported on a vehicle body frame via a cushion rubber (see, for example, Patent Document 1). As a result, the rear suspension can be configured to be lightweight and simple.
JP 2001-213379 A

By the way, the above conventional configuration is applied to a unit swing type rear suspension, but a configuration suitable for a normal swing arm type rear suspension that swings a swing arm for suspension of a rear wheel separately from an engine is desired. Has been.
Accordingly, an object of the present invention is to reduce the weight and simplify the suspension parts in a rear suspension structure of a saddle-ride type vehicle provided with a swing arm type rear suspension.

  As a means for solving the above-mentioned problem, the invention described in claim 1 is to swing a swing arm for suspension of a rear wheel (for example, the swing arm 11 of the embodiment) separately from the engine (for example, the engine 16 of the embodiment). In a rear suspension structure of a riding type vehicle (for example, the motorcycle 1 of the embodiment), a pivot portion (for example, of the embodiment) that supports the swing arm at a rear end portion of the crankcase (for example, the crankcase 18 of the embodiment) of the engine. A pivot portion 60) is provided, an under bracket (for example, the under bracket 95 of the embodiment) is attached below the pivot portion in the crankcase, and the rear portion of the under bracket is behind the pivot portion and the swing arm. Provide a rear extension (for example, rear extension 95a of the embodiment) extending to the vicinity, Characterized in that a rear cushion with a cushion rubber (rubber cushion 104 of the example embodiment) between the rearward extending portion and the swing arm (e.g., the rear cushion 105 in the embodiment).

  According to a second aspect of the present invention, the swing arm includes a cross member (for example, the cross member 102 of the embodiment) that connects the front portions of the left and right arms (for example, the left and right arms 101 of the embodiment). Is provided with a cushion holder for holding the outer periphery of the cushion rubber (for example, the cushion holder 106 of the embodiment), and the under bracket has a load input member (for example, the load input plate 107 of the embodiment) penetrating the cushion rubber. Is provided.

  According to a third aspect of the present invention, a rear frame (for example, the rear frame 2R of the embodiment) for supporting a passenger seat (for example, the seat 13 of the embodiment) is located above the pivot portion at the rear portion of the crankcase. Fastened and supported, and at least one of the rear fastening portions for fastening the rear frame (for example, the rear fastening portions 82 and 83 of the embodiment) (for example, the upper rear fastening portion 83 of the embodiment) is provided in the vicinity of the pivot portion. It is characterized by.

  The invention described in claim 4 is characterized in that a damper (for example, the damper 108 of the embodiment) for absorbing the swing energy of the swing arm is provided between the rear frame and the swing arm.

  The invention described in claim 5 is characterized in that a connecting portion (for example, the upper damper support portion 12k of the embodiment) of the damper to the rear frame is provided in the vicinity of at least one of the rear fastening portions.

According to the first aspect of the present invention, the swing arm is supported by the crankcase of the engine, so that the pivot frame for supporting the swing arm is eliminated to reduce the weight of the vehicle body, and the behavior of the rear wheel is increased in mass. Can be received with the engine.
In addition, by adopting a rear cushion using cushion rubber, the rear suspension can be made lighter and more compact than when a rear cushion using a metal spring is employed.
Furthermore, the rear bracket attached to the engine side (on the spring) is provided with a rear extension that extends to the swing arm side (under the spring), and a rear cushion is provided between the rear extension and the swing arm, thereby Compared with the case where an extension part extending to the engine side is provided on the arm side, the weight of the swing arm and hence the unsprung weight can be reduced, and the rear extension part (under bracket) is separated from the crankcase. As a result, the crankcase can be easily formed.
In addition, the cushion load input to the rear frame at the rear of the vehicle body can be eliminated, and the rear frame can be made lighter and more compact.

  According to the invention described in claim 2, when the swing arm swings up and down with respect to the vehicle body (engine) together with the rear wheel, the load input member provided on the vehicle body side (under bracket) holds the cushion on the swing arm side. The load input member is displaced relative to the rubber and elastically deforms the rubber layer of the adjacent cushion rubber. As described above, the rear cushion that generates the elastic force of the cushion rubber as a cushion load can be configured relatively easily.

According to the invention described in claim 3, by providing the rear fastening portion in the vicinity of the pivot portion in which the strength and rigidity are ensured, the strength and rigidity of the rear fastening portion can be easily secured without requiring reinforcement. be able to.
Further, by providing the rear fastening portion at a position above the pivot portion at the rear portion of the crankcase, it is possible to efficiently avoid interference between the rear fastening portion and the under bracket and interference between the rear frame and the swing arm. it can.

According to the fourth aspect of the present invention, the damping force generated by the damper (energy absorbing device) and the cushion load generated by the rear cushion are distributed to the rear frame and the under bracket. Light weight and compactness can be achieved.
Further, it is not necessary to give the cushion rubber damping characteristics, and heat generation of the cushion rubber can be suppressed and durability can be improved.

  According to the invention described in claim 5, by providing a connecting portion of the damper in the vicinity of the fastened portion with respect to the rear fastening portion in the rear frame, the reinforcement is particularly strengthened using the strength rigidity of the fastened portion. The strength and rigidity of the connecting portion can be easily ensured without the necessity.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the directions such as front, rear, left and right in the following description are the same as those in the vehicle unless otherwise specified. In the figure, the arrow FR indicates the front of the vehicle, the arrow LH indicates the left side of the vehicle, and the arrow UP indicates the upper side of the vehicle.

  A motorcycle 1 shown in FIG. 1 has a front frame 2F and a rear frame 2R which are separate from each other on the front and rear of the vehicle body, and a crankcase of an engine 16 in which the front frame 2F and the rear frame 2R are arranged at the center lower part of the vehicle body. 18 is connected. An underframe 2U is attached to the lower rear side of the crankcase 18. A front wheel suspension system FS is supported to be steerable at a front end portion of the front frame 2F, and an occupant seat 13 is supported above the rear frame 2R. A rear wheel suspension system RS is supported on the rear end of the crankcase 18 so as to be vertically swingable.

  Referring also to FIG. 2, the engine 16 is, for example, an air-cooled single-cylinder engine. The crankshaft 17 has a rotation center axis (crank axis) C1 along the left-right direction (vehicle body width direction) and a crankcase 18. The cylinder 19 is protruded forward from the front end of the cylinder substantially horizontally (in detail, slightly upward). In the figure, a line C2 indicates a central axis (cylinder axis) along the protruding direction of the cylinder 19, and an arrow f indicates the rotational direction of the crankshaft 17. Since the engine 16 causes the cylinder 19 to protrude substantially horizontally, when the cylinder axis C2 is extended forward, it crosses the front wheel 6 in a side view.

  The cylinder 19 has a cylinder body 21 attached to the front end portion of the crankcase 18, a cylinder head 22 attached to the front end portion of the cylinder body 21, and a head cover 23 attached to the front end portion of the cylinder head 22. Become. The cylinder 19 is separate from the crankcase 18 and is integrally attached together with the cylinder head 22 by a plurality of stud bolts or the like fixed to the front end portion of the crankcase 18.

  Referring to FIG. 1, the upper side (intake side) of cylinder head 22 is connected to the downstream side of throttle body 24 positioned above the cylinder head 22, and the air cleaner box positioned further above the upstream side of throttle body 24. 25 is connected. A base end portion of the exhaust pipe 26 is connected to the lower side (exhaust side) of the cylinder head 22. The exhaust pipe 26 is appropriately curved below the cylinder 19 and extends rearward after passing through the catalytic converter 26b, and is connected to the front end portion of the silencer 26a disposed on the right side of the rear wheel 9.

  Referring to FIGS. 1 to 3, a cylinder bore 27 is formed in the cylinder body 21 along the cylinder axis C <b> 2, and a piston 28 is slidably fitted in the cylinder bore 27. The reciprocating motion of the piston 28 is converted into rotational motion about the crank axis C1 of the crankshaft 17 via the connecting rod 29. The rotational power of the crankshaft 17 is driven by the clutches 33 and 34 arranged on the right side in the crankcase 18 and the transmission 35 arranged on the rear left side of the crankcase 18 via the transmission 35 arranged on the rear side in the crankcase 18. It is output to the sprocket 36 and transmitted from the drive sprocket 36 to the driven sprocket 36b on the left side of the rear wheel 9 through the drive chain 36a.

  Referring to FIG. 2, the engine 16 is operated with respect to the cylinder axis C <b> 2 in order to reduce the pressing force of the piston 28 against the cylinder inner surface at the time of the maximum pressure in the combustion chamber (the initial stage of the combustion (expansion) stroke) and the sliding resistance. An offset crank mechanism is employed in which the crank axis C1 is offset upward (upstream in the rotational direction f) by a predetermined amount t. In other words, the cylinder axis C2 is offset downward (downstream in the rotational direction f) with respect to the crank axis C1.

  Referring to FIG. 3, a centrifugal clutch 33 is coaxially arranged at the right end portion of the crankshaft 17, and the rotational power of the crankshaft 17 is transmitted via the centrifugal clutch 33 to a primary drive gear 37a coaxially arranged on the left and right inner sides thereof. Is done. The primary drive gear 37a meshes with a relatively large-diameter primary driven gear 37b arranged coaxially on the right side of the main shaft 38a behind the crankshaft 17. A generator 39 is coaxially disposed at the left end of the crankshaft 17.

A multi-plate clutch 34 that can be intermittently operated by the driver is coaxially disposed at the right end of the main shaft 38a, and the rotational power transmitted to the primary driven gear 37b is transmitted to the main shaft 38a via the multi-plate clutch 34.
Referring also to FIG. 2, a counter shaft 38b is disposed behind the main shaft 38a, and a transmission gear group (not shown) is supported on each of the shafts 38a and 38b so that the driver can perform a speed change operation. 35 is configured. The left end portion of the counter shaft 38b projects out of the crankcase 18, and the drive sprocket 36 is attached to the left end portion so as to be integrally rotatable. Each shaft 17, 38a, 38b is disposed on a substantially horizontal plane.

  2, intake and exhaust ports 41a and 41b for connecting the throttle body 24 and the exhaust pipe 26 are formed above and below the cylinder head 22, respectively. The cylinder inner openings (combustion chamber side openings) of the ports 41a and 41b are opened and closed by single or plural intake and exhaust valves 42a and 42b, respectively. The opening and closing operations of the ports 41a and 41b by the intake and exhaust valves 42a and 42b are performed by a single camshaft 44 via intake and exhaust rocker arms 43a and 43b having cam rollers, respectively.

  The camshaft 44 is disposed with its rotation axis C3 along the left-right direction. A cam drive sprocket 45 having a relatively large diameter is coaxially fixed to the left end portion of the camshaft 44, and endlessly connected to the cam driven sprocket 45 and a cam drive sprocket 46 having a relatively small diameter coaxially fixed to the left side portion of the crankshaft 17. A cam chain 47 is wound around. Via these sprockets 45 and 46 and the cam chain 47, the camshaft 44 is driven in linkage with the crankshaft 17 to open and close the valves 42a and 42b. A cam chain tensioner 51 mainly including a tensioner roller 52, a swing arm 53, and a lifter 54 is disposed on the left inner side of the crankcase 18.

  Referring to FIG. 3, the case main body 55 that supports the shafts 38 b and the like in the crankcase 18 is divided into left and right case bodies 56 and 57 with a dividing surface CS orthogonal to the crank axis C <b> 1 as a boundary. In this embodiment, the dividing plane CS coincides with the left and right center plane of the vehicle body, but may be offset to the left or right with respect to the center plane. Left and right case covers 58 and 59 are attached to the left and right outer sides of the left and right case bodies 56 and 57, respectively. The left case body 56 and the left case cover 58 constitute a generator case 58a that accommodates the generator 39 and the like, and the right case body 57 and the right case cover 59 constitute a clutch case 59a that accommodates the clutches 33, 34, and the like.

  Referring to FIGS. 1 and 2, a pivot portion 60 that supports a front end portion of a swing arm 11 for suspending a rear wheel so as to be swingable up and down is provided at an upper and lower intermediate portion of a rear end portion of the crankcase 18 (case body 55). Is provided. The pivot portion 60 has a mountain shape in a side view and protrudes rearward from the rear surface of the crankcase 18 in a mountain shape in a side view. The projecting tip side of the pivot portion 60 has a boss shape along the left-right direction, and the front end portion of the swing arm 11 is pivotally supported by the pivot portion 60 via a pivot shaft along the left-right direction.

  2 and 3, a starter motor 61 for starting the engine 16 is disposed above the front portion of the case body 55 of the crankcase 18. The starter motor 61 is disposed with the rotation axis of the drive shaft 62 extending in the left-right direction, and protrudes leftward from the cylindrical motor main body 63 along the rotation axis and the left end portion of the motor main body 63. And the drive shaft 62. The starter motor 61 is disposed above the case body 55 so as to straddle the dividing surface CS in the left and right directions.

  The left side portion of the starter motor 61 is attached to the gear housing 65 protruding from the upper left of the crankcase 18 from the right side. The gear housing 65 has a motor holder 66 projecting in a mountain shape in a side view on the front upper side of the left case body 56, and an upper portion of the left case cover 58 so as to overlap with the right side of the motor holder 66 in a side view. And a holder cover 67 projecting from the head. A part of starter transmission mechanism 71 arranged in generator case 58a is accommodated in gear housing 65. The left end of the motor main body 63 of the starter motor 61 is held on the right side of the projecting top of the motor holder 66, and the drive shaft 62 of the starter motor 61 faces the gear housing 65.

  The starter transmission mechanism 71 includes a large-diameter idle gear 72 that meshes with a pinion gear 62b formed on the outer periphery of the distal end portion of the drive shaft 62, a small-diameter idle gear 73 that is provided coaxially with the large-diameter idle gear 72, and that can rotate integrally therewith. A one-way clutch 75 that meshes with the small-diameter idle gear 73 and engages the large-diameter driven gear 74 that is coaxially and relatively rotatable with the crankshaft 17, and the outer rotor 39 a that rotates integrally with the crankshaft 17 in the generator 39. It has. The one-way clutch 75 allows the rotational power of the drive shaft 62 to be transmitted to the crankshaft 17, while the rotational power of the crankshaft 17 cannot be transmitted to the drive shaft 62.

  When electric power is supplied to the starter motor 61 from an in-vehicle power source (not shown) by the driver's operation, the drive shaft 62 rotates to move the crankshaft 17 via the starter transmission mechanism 71 in the starting direction of the engine 16 (the aforementioned The engine 16 can be started by rotating in the direction of the arrow to cause cranking. Further, after the engine 16 is started, the transmission of the rotational power of the crankshaft 17 to the starter transmission mechanism 71 and the starter motor 61 is interrupted by the one-way clutch 75.

  Before and after the motor holder 66, front and rear motor mounting portions 76 and 77 are provided respectively protruding from the front and rear inclined surfaces in a mountain shape when viewed from the side. The front motor attachment portion 76 is provided near the tip of the motor holder 66, and the rear motor attachment portion 77 is provided near the base end of the motor holder 66. The front and rear motor mounting portions 76 and 77 are provided at substantially the same height before and after the drive shaft 62 is sandwiched.

  As shown in FIGS. 2 and 4, the upper and lower sides of the front frame 2F are connected to the upper and lower sides of the front end portion of the cylinder 19 at the front end portion of the crankcase 18 (case body 55). A front fastening portion 80 and a lower front fastening portion 81 are provided. The upper front fastening portion 80 has a mountain shape when viewed from the side and protrudes forward from the cylinder mating surface (a surface perpendicular to the cylinder axis C2) 55a at the front end of the crankcase 18, and the lower front fastening portion 81 also has a mountain shape when viewed from the side. Thus, it protrudes obliquely downward and forward so as not to protrude forward from the cylinder alignment surface 55a.

  Referring also to FIG. 5, each of the front fastening portions 80 and 81 has a boss shape extending in the left-right direction, and can be inserted or screwed into a fastening bolt. Each of the front fastening portions 80 and 81 is also a fastening portion that fastens the front end portions of the left and right case bodies 56 and 57 of the case main body 55 integrally. The front fastening portions 80 and 81 are respectively sandwiched between the left and right fastened portions 80a and 81a of the front frame 2F, and these are integrally formed by a combination of long bolts 80b and 81b and nuts 80c and 81c along the left-right direction. It is concluded.

The upper front fastening portion 80 is located obliquely forward and upward of the crank axis C1, and the lower front fastening portion 81 is located obliquely forward and downward of the crank axis C1. In other words, the front fastening portions 80 and 81 are arranged so as to be distributed above and below the crank axis C1 in a side view.
Here, the cylinder 19 is disposed at a relatively low position with respect to the crankcase 18 because the cylinder axis C2 is offset downward with respect to the crank axis C1 as described above. 80 and 81 are also arranged at a relatively low position, so that the height of the rear portion of the front frame 2F is kept low.

  As shown in FIGS. 2 and 14, intermediate rear fastening portions for connecting the front and rear of the front portion (lower portion) of the rear frame 2 </ b> R are respectively connected to the upper side of the front and rear middle portion and the upper side of the rear end portion of the crankcase 18 (case body 55). 82 and upper rear fastening portion 83 are provided. The intermediate rear fastening portion 82 forms a mountain shape when viewed from the side and protrudes upward from the upper surface of the crankcase 18, and the upper rear fastening portion 83 similarly forms a mountain shape when viewed from the side and projects obliquely upward and rearward from the upper inclined surface of the pivot portion 60.

  Referring to FIGS. 5, 14, and 17 together, each of the rear fastening portions 82 and 83 has a boss shape extending in the left-right direction, and a fastening bolt can be inserted or screwed therein. The rear fastening portions 82 and 83 are also fastening portions that integrally fasten the rear upper sides of the left and right case bodies 56 and 57 of the case main body 55. The rear fastening portions 82 and 83 are respectively sandwiched between the left and right fastened portions 82a and 83a of the rear frame 2R, and these are integrally formed by a combination of long bolts 82b and 83b and nuts 82c and 83c along the left-right direction. It is concluded.

Referring to FIG. 2, the intermediate rear fastening portion 82 is located obliquely above and rearward of the crank axis C1, and the upper front fastening portion 80 is located obliquely above and forward of the crank axis C1. In other words, the intermediate rear fastening portion 82 and the upper front fastening portion 80 are arranged so as to be distributed forward and rearward relative to the crank axis C1.
Note that the gear housing 65 is located above the crank axis C1, and it can be said that the intermediate rear fastening portion 82 and the upper front fastening portion 80 are disposed before and after sandwiching the gear housing 65.
On the other hand, the upper rear fastening portion 83 is disposed almost directly above the pivot portion 60 and in close proximity thereto.

  Here, the rear motor mounting portion 77 is provided between the intermediate rear fastening portion 82 and the gear housing 65, and between the rear motor mounting portion 77 and the intermediate rear fastening portion 82, these are crossed. In this way, a rib 85 is provided that rises from the upper surface of the crankcase 18. The rear motor attaching portion 77 and the intermediate rear fastening portion 82 are connected to each other via the ribs 85 to reinforce each other.

  The front fastening portions 80 and 81 for the front frame 2F and the rear fastening portions 82 and 83 for the rear frame 2R are provided separately from each other and separated from each other in the front-rear direction. That is, the front frame 2F and the rear frame 2R are fastened to the crankcase 18 separately from each other and separated from each other in the front-rear direction. At this time, the starter motor 61 and the gear housing 65 are located between the front frame 2F and the rear frame 2R. Therefore, neither the front frame 2F nor the rear frame 2R exists above the front part of the crankcase 18 (above the starter motor 61 and the gear housing 65).

  As described above, the motorcycle 1 has the engine 16 having the substantially horizontal cylinder 19 disposed in the lower center of the vehicle body, and the front frame 2F and the rear frame 2R are eliminated from the space above the front portion of the crankcase 18. As shown in FIG. 1, the height of the vehicle body between the bar handle 8 and the seat 13 can be kept low, and the space can be used as the straddling portion 69 when the vehicle gets on and off, thereby improving the boarding / exiting performance.

  2 and 14, a lower rear fastening portion 84 for fastening the front and rear intermediate portions of the underframe 2U is provided below the rear end portion of the crankcase 18 (case body 55). The lower rear fastening portion 84 has a mountain shape in side view and protrudes rearward from the rear surface of the crankcase 18.

Referring to FIGS. 5 and 17 together, the lower rear fastening portion 84 has a boss shape extending in the left-right direction so that a fastening bolt can be inserted or screwed therein. The lower rear fastening portion 84 is also a fastening portion that integrally fastens the lower side of the rear end portions of the left and right case bodies 56 and 57 of the case body 55 together. The lower rear fastening portion 84 is sandwiched between the left and right fastening portions 84a of the under frame 2U, and these are fastened together by a combination of a long bolt 84b and a nut 84c along the left-right direction.
The lower rear fastening portion 84 is disposed at a site that is spaced downward from the pivot portion 60 and slightly forward of the pivot portion 60.

  As shown in FIGS. 1, 4, and 5, the front frame 2 </ b> F includes a cylindrical head pipe 3 that constitutes a front end portion thereof, and a pair of left and right that linearly extend obliquely downward and rearward from the head pipe 3 in a side view. The main tube 4 and the front cross member 5 extending in the left-right direction provided between the longitudinal intermediate portions of the left and right main tubes 4 are mainly used. The front frame 2F is an integrally cast product using, for example, an aluminum alloy, and is divided (die-cut) along the central axis (steering axis) C4 of the head pipe 3 that is inclined so as to be located on the rear side toward the upper side. Made. The front frame 2F has a substantially symmetrical configuration. FIG. 5 is a view as seen from an arrow A parallel to the steering axis C4 (the mold dividing direction).

  The left and right main tubes 4 have a vertically long cross-sectional shape (see FIG. 6). When viewed from above, the main tubes 4 extend from the head pipe 3 by a predetermined amount so as to branch obliquely rearward and leftward and rightward (see FIG. 5). It bends along the surface CS and extends rearward substantially parallel to each other. In the side view, the left and right main tubes 4 extend from the head pipe 3 to the rear thereof in a straight line and slightly widen with a steep slope from the direction perpendicular to the steering axis C4 (corresponding to the parting surface of the front frame 2F). (See FIG. 1).

  Referring also to FIG. 6, the cross-sectional shape of the left and right main tubes 4 is a substantially U-shape that is deep in the mold dividing direction (longitudinal direction) and opens toward one side (diagonally lower front). The vertical width of the cross-sectional shape of the left and right main tubes 4 changes so as to increase slightly toward the engine 16 side (rear side), while the horizontal width is substantially constant. Hereinafter, the left and right inner and outer walls of the left and right main tubes 4 are referred to as inner and outer walls 4a and 4b, and the wall along the upper edge (rear edge) is referred to as the upper wall 4c. The inner and outer walls 4a and 4b are formed in a flat plate shape that is substantially orthogonal to the left-right direction, but a slight draft angle is secured between them. In addition, ribs 4d extending over the walls 4a, 4b, and 4c are appropriately formed inside the cross section of the left and right main tubes 4.

  4 and 5, the rear (lower) upper side of the left and right main tubes 4 reaches the upper side of the front end of the crankcase 18 and is integrally fastened to the upper front fastening portion 80. On the other hand, the rear lower side of the left and right main tubes 4 is curved forward and immediately behind the lower side of the front end of the crankcase 18, then reaches the lower side of the front end of the crankcase 18, and is also integrated with the lower front fastening portion 81. To be concluded.

  Referring to FIG. 5, the rear part of the left and right main tubes 4 is tapered when the outer wall 4b is slightly inclined in a top view, and the upper and lower parts of the left and right main tubes 4 are bosses extending in the left-right direction across the inner and outer walls 4a and 4b, respectively. The upper and lower fastened portions 80a and 81a are integrally provided. The upper front fastening portion 80 is sandwiched between the left and right upper fastening portions 80a, and these are fastened together by a combination of the long bolt 80b and the nut 80c. Similarly, the lower front fastening portion 81 is sandwiched between the left and right lower fastening portions 81a, and these are fastened together by a combination of the long bolts 81b and 81c and the nut.

  Referring to FIG. 4, the cross member 5 has a substantially U-shaped cross-sectional shape that opens obliquely downward and forward, and both ends of the cross member 5 are lower edges of the inner wall 4 a in the middle portion in the longitudinal direction of the left and right main tubes 4. Joined near (front edge). The upper wall 5a of the cross member 5 is provided along the longitudinal direction of the left and right main tubes 4, the front wall 5b is provided substantially orthogonally to the upper wall 5a, and the rear wall 5c is provided along the mold dividing direction. It is provided to be inclined with respect to 5b.

  Referring to FIG. 1, a left and right front fork 7 that pivotally supports a front wheel 6 is pivotally supported on the head pipe 3 via a steering stem 7a. The left and right front forks 7 and the steering stem 7a are mainly used as the front wheel. A suspension system FS is configured. A steering bar handle 8 is attached to the upper portion of the steering stem 7a.

Referring to FIGS. 1 and 6, the air cleaner box 25 and the throttle body 24 are disposed between the left and right main tubes 4.
The air cleaner box 25 accommodates and holds a flat air cleaner element 25b in a rectangular parallelepiped air cleaner case 25a, and is provided so as to overlap the front portions of the left and right main tubes 4 in a side view.

The left and right side walls of the air cleaner case 25a are substantially parallel to and close to the inner side walls 4a of the left and right main tubes 4, and are appropriately engaged and supported by the left and right inner side walls 4a. It is sandwiched between the tubes 4.
The throttle body 24 located obliquely below and rearward of the air cleaner case 25a is disposed adjacent to the rear of the cross member 5. That is, since the cross member 5 is positioned in front of the throttle body 24, mud or the like can be hardly applied to the throttle body 24.

Here, the front frame 2F ′ shown in FIGS. 7 and 8 has a direction in which the crankcase 18 is fastened to a direction parallel to the cylinder axis C2 (a direction perpendicular to the vehicle body width direction).
At the same position as the front fastening portions 80 and 81 at the front end of the crankcase 18 (case body 55), there are an upper front fastening portion 80 ′ and a lower fastening portion that respectively connect the top and bottom of the rear portion (lower portion) of the front frame 2F ′. A front fastening portion 81 ′ is provided. Each of the front fastening portions 80 ′ and 81 ′ has a front end surface along the cylinder mating surface 55a and a screw hole along the cylinder axis C2, and is provided integrally with the front end portion of the crankcase 18. Each front fastening portion 80 ′, 81 ′ is provided in a pair of left and right.

  On the other hand, boss-like upper and lower fastened portions 80 a ′ and 81 a ′ along the cylinder axis C <b> 2 are integrally provided above and below the rear portion of the left and right main tubes 4 in the front frame 2 </ b> F ′ so as to project inward in the left and right directions. These fastened portions 80a 'and 81a' are brought into contact with the front fastened portions 80 'and 81' from the front, respectively, and bolts 80b 'and 81b' passing through the fastened portions 80a 'and 81a' from the front are provided. By screwing and tightening the front fastening portions 80 ′ and 81 ′, the rear portion of the front frame 2 F ′ is fastened integrally with the front end portion of the crankcase 18.

  According to this configuration, variation in the caster angle of the front wheels 6 can be suppressed as compared with the case where the fastening direction of the front fastening portions 80 and 81 is parallel to the vehicle body width direction as in the front frame 2F.

  Referring to FIGS. 1 and 11, the rear frame 2 </ b> R mainly includes a left and right split-type rear frame body 12. The left and right rear frame bodies 12 extend linearly from the front part coupled to the upper rear part of the crankcase 18 diagonally upward and rearward, and have a vertically long cross-sectional shape. Each of the left and right rear frame main bodies 12 is an integrally cast product using, for example, an aluminum alloy, and is divided (die-cut) along the left and right directions. The left and right rear frame bodies 12 have a substantially bilaterally symmetric configuration.

  The cross-sectional shape of the left and right rear frame bodies 12 is a substantially U-shape that is shallow in the dividing direction and opens toward one side (the left and right inner sides). While the vertical width of the cross-sectional shape of the left and right rear frame main body 12 changes so as to increase slightly toward the engine 16 side (front side), the horizontal width is substantially constant. Hereinafter, the left and right outer walls of the left and right rear frame body 12 are referred to as outer walls 12a, and the upper and lower walls are referred to as upper and lower walls 12b and 12c, respectively. The outer side wall 12a is slightly inclined so as to be located on the left and right inner sides as it is on the lower side, and is slightly curved in a convex shape on the left and right outer sides. Front and rear ribs 12d and 12e for supporting the fuel tank 15, which will be described in detail later, are partially formed on the left and right inner sides of the outer side wall 12a.

  Referring also to FIG. 14, the front part (lower part) of the left and right rear frame body 12 reaches the upper rear part of the crankcase 18, the front side is integrally fastened to the intermediate rear fastening part 82, and the rear side is the upper part. Fastened integrally to the rear fastening portion 83. Each of the rear fastening portions 82 and 83 is located above the crank axis C1 and the pivot portion 60. Therefore, the left and right rear frame bodies 12 are fastened above the crank axis C1 and the pivot portion 60 in the crankcase 18. The

  Referring to FIG. 1, the lower wall 12 c of the left and right rear frame body 12 is bent obliquely upward and forward above the rear wheel 9 to form a rear wall 12 f of the left and right rear frame body 12 and an upper seat 13 thereof. To the rear end. On the other hand, the upper wall 12b of the left and right rear frame body 12 bends forward and upward from the rear wall 12f to form the rear front wall 12g of the left and right rear frame body 12, and the rear lower edge of the seat 13 above it. To. The rear upper edge of the rear rising connecting the upper end of the rear wall 12 f and the upper end of the rear front wall 12 g in the left and right rear frame main body 12 is inclined along the rear lower edge of the seat 13.

  Here, the sheet 13 is integrally formed with a cushion layer 13b having a predetermined thickness on a bottom plate 13a made of a synthetic resin such as polypropylene, and its lower edge shape is formed along the outer edge shape of the bottom plate 13a. The front lower edge of the sheet 13 is formed in a curved shape that protrudes downward in a side view, and the rear lower edge is formed in a straight line that rises rearward in a side view. The central portion of the bottom plate 13a has an upwardly convex curve, and the thickness of the cushion layer 13b, which also has an upwardly convex curve, is maintained appropriately, and the capacity of the article storage box 14 below the seat 13 is increased.

  The front end of the bottom plate 13a of the seat 13 is rotatably supported by the front end of the article storage box 14 below the hinge 13c along the vehicle body width direction, and the rear end of the bottom plate 13a is The sheet 13 can be engaged with the lock mechanism 13d disposed at the rear end of the storage box 14 with the article storage box 14 closed.

  A connecting boss 12h that connects the rear portions of the left and right rear frame main bodies 12 directly or via a predetermined connecting member is provided behind the rear front walls 12g of the left and right rear frame main bodies 12, respectively. The locking mechanism 13d is disposed between the connecting boss 12h (or the connecting member) and the rear front wall 12g, and the locking mechanism 13d is attached to the left and right connecting boss 12h (or the connecting member).

  Referring also to FIG. 11, the article storage box 14 has a box shape that opens upward, and is made of a synthetic resin such as polypropylene, for example. The upper opening 14a of the article storage box 14 is formed along the lower edge shape of the seat 13 in front of the rear front wall 12g of the left and right rear frame main body 12, and the article storage box so as to hang downward from the lower edge shape. 14 front walls 14b and left and right side walls 14c are formed. The front wall 14b and the left and right side walls 14c form the exterior of the vehicle between the seat 13 and the left and right rear frame body 12.

Referring to FIG. 1, the front wall 14 b of the article storage box 14 is inclined so as to be located on the rear side (side away from the engine 16) as viewed from the side, and the straddling portion 69 is enlarged. Yes.
A rear wall 14d is formed at the rear end of the article storage box 14 so as to stand along the rear front wall 12g in a side view. A bottom wall 14e is formed at the bottom of the article storage box 14 so as to be inclined along the upper wall 12b of the left and right rear frame body 12 in a side view.

  Referring to FIG. 11, the article storage box 14 is fastened and supported by the upper walls 12 b of the left and right rear frame bodies 12 at appropriate locations on both sides of the bottom wall 14 e. In the figure, reference numeral 14f denotes a clip nut attached to the upper wall 12b of the left and right rear frame body 12, and reference numeral 14g denotes a stepped bolt that is screwed onto the clip nut 14f from above and tightened.

  Referring to FIG. 1, the article storage box 14 opens and closes the upper opening 14a as the seat 13 rotates about the hinge shaft 13c. The article storage box 14 is locked in a state in which the upper opening 14a is closed by engaging the seat 13 with the upper opening 14a closed with the locking mechanism 13d, and in this state, an occupant can be seated on the seat 13. . On the other hand, when a predetermined unlocking operation is performed from the locked state, the lock mechanism 13d is unlocked and the seat 13 can be rotated around the hinge shaft 13c, and the upper opening 14a of the article storage box 14 is opened. It becomes possible.

Referring to FIGS. 1 and 9 to 11, a fuel tank 15 made of a synthetic resin such as polypropylene is disposed between the left and right rear frame bodies 12.
The fuel tank 15 is provided so as to incline rearward so as to overlap with the left and right rear frame bodies 12 in a side view, and to narrow the left and right width toward the rear side in a top view.

  The fuel tank 15 includes left and right side walls 15 a along the outer wall 12 a of the left and right rear frame body 12, an upper wall 15 b along the upper wall 12 b of the left and right rear frame body 12 in a side view, and a tread surface on the upper front portion of the rear wheel 9. A lower wall 15c that is spaced from the front wall 15c by a predetermined distance and curved along the lower wall 15c; a substantially horizontal front lower wall 15d that extends between the front end (lower end) of the lower wall 15c and the front end (lower end) of the upper wall 15b; A rear wall 15e that rises upward from the rear end (upper end) of the wall 15c, and a substantially horizontal rear upper wall 15f that extends between the upper end of the rear wall 15e and the rear end (upper end) of the upper wall 15b. Become. Both sides of the lower wall 15c are formed flat so as to face the upper wall 15b (see FIG. 11).

  Referring to FIGS. 1 and 9, the rear upper wall 15f and the rear wall 15e are disposed between the rear portions of the left and right rear frame bodies 12 and behind the lock mechanism 13d and the left and right connecting bosses 12h. The rear upper wall 15f is located at the upper end of the fuel tank 15. The rear upper wall 15f is formed with a fuel inlet 15g of the fuel tank 15, and a fuel cap 15h is detachably attached to the fuel inlet 15g.

  Referring to FIG. 9, a fuel pump 99 that pumps fuel in the fuel tank 15 toward, for example, an injector provided in the throttle body 24 is disposed inside the front portion of the fuel tank 15. The fuel pump 99 is mounted on a front lower wall 15d positioned at the lower end of the fuel tank 15, and is connected to the injector from a feed nozzle 99a protruding below the front lower wall 15d through a fuel hose and the like.

A fuel remaining amount sensor is provided on the upper portion of the fuel pump 99. The fuel remaining amount sensor has a swing type float 99b, and the float 99b can swing between a posture inclined forward and downward and a posture inclined forward and upward. In the front portion of the upper wall 15b of the fuel tank 15, a convex bulging portion 15i is formed obliquely forward and upward so as to avoid this when the float 99b assumes a forward tilting posture.
Referring to FIG. 11, the bottom wall 14e of the article storage box 14 is overlapped on the upper wall 15b of the fuel tank 15, and a bulging portion similar to the bulging portion 15i is formed on the bottom wall 14e (illustrated). (Omitted). Further, chamfered portions 15 j that avoid the fastening portions of the left and right rear frame main bodies 12 and the article storage box 14 are formed at appropriate locations on both sides of the upper portion of the fuel tank 15.

  Referring to FIGS. 1 and 9 to 11, front and rear convex portions 15 k that are formed in a long oval shape along the inclination direction (longitudinal direction) of the fuel tank 15 in a side view, respectively, before and after the left and right side walls 15 a of the fuel tank 15. , 15l are projected toward the left and right outer sides. On the other hand, front and rear ribs 12d and 12e are formed in front and rear of the outer wall 12a of the left and right rear frame main body 12 and have the same elliptical shape as the convex portions 15k and 15l in side view. The inner peripheral sides of the front and rear ribs 12d and 12e are front and rear recesses 12i and 12j into which front and rear protrusions 15k and 15l can be fitted via cup-shaped rubber members g that open toward the left and right inner sides, respectively. The oblong front and rear convex portions 15k and 15l do not have to extend along the longitudinal direction of the fuel tank 15. For example, the front and rear convex portions 15k and 15l may be arranged substantially horizontally in a side view. 15l may be arranged at different angles.

  The front portions of the left and right rear frame main bodies 12 are fastened to the crankcase 18 with the left and right front and rear convex portions 15k and 15l of the fuel tank 15 fitted in the front and rear concave portions 12i and 12j of the left and right rear frame main bodies 12, respectively. At the same time, the fuel tank 15 is securely clamped between the left and right rear frame bodies 12 by connecting the rear portions of the left and right rear frame bodies 12 together. In addition, the structure which concerns on the rear convex part 15l and the rear recessed part 12j shown in FIG. 11 shall have the front convex part 15k and the front recessed part 12i similarly.

Here, the fuel tank 15 ′ shown in FIG. 13 has, for example, a hollow monaca structure in which left and right divided bodies B1 and B2 having a divided surface BS substantially parallel to the divided surface CS are integrally joined to each other.
The left and right divided bodies B1 and B2 are container-like ones opened to the left and right inner sides. The left divided body B1 has left projections 15k and 15l on the bottom (left side wall 92b), and the right divided body B2 has its left side. By forming the right protrusions 15k and 15l on the bottom (right wall 92b), the entire fuel tank 15 (particularly the protrusions 15k and 15l) can be easily formed.

The dividing surface BS between the left and right divided bodies B1 and B2 is offset to the right side of the dividing surface CS, for example, and the joint flange F of the left and right divided bodies B1 and B2 is located near the upper and lower walls 12b and 12c of the right rear frame body 12. To move. Thus, by offsetting the joining flanges F of the left and right divided bodies B1 and B2 to the left or right, a decrease in the clearance with the rear wheel 9 is suppressed, and the joining flange F is avoided on the bottom wall 14e of the article storage box 14. This also makes it difficult to get in the way when the convex portion 14h is formed.
The fuel tank 15 ′ is a unit in which the steel plate press-formed product is integrally bonded by welding or the like, but this may be a unit in which the resin molded product is integrally bonded by bonding or the like.

  Referring to FIGS. 1, 9, 10, and 12, the rear wall 15e of the fuel tank 15 is integrally provided with a tail lamp 91a, a left and right rear turn signal 91b, a license plate 91c, and a rear stay 92 that supports the reflector 91d. It is formed. The rear stay 92 extends linearly from the rear wall 15e of the fuel tank 15 obliquely downward and rearward, and has a substantially U-shaped cross-sectional shape that is shallow in the vertical direction and opens downward. The rear stay 92 has a substantially constant vertical width when viewed from the side, and narrows the lateral width toward the rear so as to be continuous with the fuel tank 15 when viewed from the top. Hereinafter, the upper wall of the rear stay 92 is denoted by reference numeral 92a, and the left and right side walls are denoted by reference numeral 92b.

  Rear turner mounting bases 92c are respectively provided at the rear portions of the left and right side walls 92b of the rear stay 92 so as to protrude outward in the left and right directions. The rear end portion of the rear stay 92 is a tail lamp mounting portion 92d. The tail lamp 91a functions as a tail lamp and a brake lamp, and also serves as a number lamp that illuminates the license plate 91c disposed below the tail lamp 91a.

  An upper protruding portion 92e is formed on the rear portion of the upper wall 92a of the rear stay 92 to expand the tail lamp mounting portion 92d upward. The tail lamp mounting portion 92d is inclined so as to be positioned on the front side toward the upper side, and the lower portion is formed with a wider left and right width. A tail lamp 91a is attached to the tail lamp attachment portion 92d via a base portion 91e. A license plate stay 92f is integrally formed below the base portion 91e, and a reflector stay 92g is integrally formed below the license plate stay 92f.

  Since the rear stay 92 has a flat open cross-sectional shape, it can be said that the rear stay 92 has a low-rigidity portion 93 at its front-rear intermediate portion. The low-rigidity portion 93 has a lower rigidity than the main body portion of the fuel tank 15 having a hollow closed cross-sectional shape. That is, even when an external force is applied to the rear stay 92 protruding rearward from the rear frame 2R from behind the vehicle, the rear stay 92 can be easily deformed by the low rigidity portion 93, and the external force is transmitted to the fuel tank 15. Is suppressed. In addition, the said open cross-sectional shape is what opened one side of the closed cross-sectional shape, and includes various shapes, such as not only a U-shape but C shape and V shape.

The rear stay 92 is provided so as to cover the upper rear portion of the rear wheel 9, and the rear stay 92 and the lower wall 15 c of the fuel tank 15 constitute a rear fender 94.
The license plate stay 92f and the reflector stay 92g may be formed integrally with the rear stay 92. Alternatively, the rear stay 92 and the rear fender 94 may be provided integrally with the fuel tank 15 by means such as adhesion or fastening (including welding if the fuel tank 15 ′ is made of a steel plate).

1, 14, and 17, the under frame 2 </ b> U connects the left and right under brackets 95 that form a substantially crescent shape that protrudes obliquely downward and rearward in a side view, and the rear lower side of the left and right under brackets 95. Main stand pivot shaft 96 is mainly used.
Left and right fastened portions 84a are formed on the upper sides of the front and rear intermediate portions of the left and right under brackets 95 so as to protrude upward in a side view, and the lower rear fastening portion 84 is sandwiched between the left and right fastened portions 84a. Fastened together. The left and right under brackets 95 are mainly attached to the left and right to-be-fastened portions 84a at portions below the pivot portion 60 in the crankcase 18.

  Referring to FIG. 14, a portion of the left and right under bracket 95 behind the lower rear fastening portion 84 (fastened portion 84a) (hereinafter referred to as a rear extension portion 95a) is inclined obliquely upward and rearward in a side view. It extends to the vicinity of the swing arm 11 behind the part 60. On the other hand, left and right steps 95b for occupant footrests are supported above the front end portions of the left and right under brackets 95, respectively.

  A base end portion of a main stand (center stand) 97 that supports the vehicle body in an upright state is rotatably supported on the main stand pivot shaft 96. A stand bracket 98a is fixed to the lower side of the front portion of the left under bracket 95, and a base end portion of a side stand 98 that supports the vehicle body in an upright state inclined to the left is rotatably supported on the stand bracket 98a. . In addition, the front part of the left and right under bracket 95 is slender with respect to the rear part.

Referring to FIGS. 14 and 15, the swing arm 11 is formed by integrally joining, for example, a plurality of types of steel materials or aluminum alloy materials by welding or the like, and the left and right arms 101 extending linearly back and forth, and the left and right arms The cross member 102 that connects the front portions of the arms 101 and the left and right arm pivot portions 103 provided at the front ends of the left and right arms 101 are provided.
The left and right arms 101 have, for example, a hollow square cross-sectional shape, and the left and right ends of the rear wheel axle are supported at the rear end. On the other hand, the front end portions of the left and right arms 101 are cut out in a circular arc shape when viewed from the side, and the front end portions are aligned and welded together in alignment with the outer periphery of the cylindrical arm pivot portion 103 along the left and right direction.

  The left and right arm pivot portions 103 are coaxial with each other, and a bearing 103a such as a needle bearing is fitted on the inner periphery thereof. On the other hand, the pivot part 60 of the crankcase 18 is fixedly provided with a pivot pipe 60a penetrating left and right. The left and right side portions of the pivot pipe 60a are slightly tapered in diameter, the left and right ends thereof reach the inner ends of the left and right arm pivot portions 103, and the left and right ends are inner ends of the inner collar 103b fitted to the inner periphery of the bearing 103a. Abut. Then, the pivot pipe 60a and the left and right inner collars 103b are fastened together by a combination of a long bolt (pivot shaft) 103c and a nut 103d along the left and right direction, so that the front end of the swing arm 11 becomes the rear end of the crankcase 18 It is pivotally supported so that it can swing up and down. The cylindrical portion corresponding to the pivot pipe 60a may be integrally formed with the left and right case bodies 56 and 57 of the case body 55, respectively.

The cross member 102 has a substantially rectangular cross-sectional shape in which an inclined wall 102 a that rises forward is formed on the lower side of the front part, and extends linearly to the left and right. Welded to. The left and right gussets 102b are integrally welded between the rear side of the left and right side portions of the cross member 102 and the inside of the front portion of the left and right arms 101, respectively.
A rear cushion 105 using a cushion rubber 104 is formed between the cross member 102 and the rear extension 95a of the left and right under bracket 95 which is a component on the engine 16 side.

  Referring also to FIG. 16, a cushion holder 106 that holds the cushion rubber 104 is integrally provided below the left and right central portions of the cross member 102, and cushion rubber is provided at the rear left and right middle portions of the left and right under brackets 95. A load input plate 107 penetrating the left and right 104 is integrally provided. When the cushion rubber 104 is displaced with respect to the load input plate 107 by the input from the swing arm 11, the cushion rubber 104 is elastically deformed to generate a reaction force (cushion load) against the displacement. That is, a single rear cushion 105 is disposed on the swing base end side of the swing arm 11 and on the left and right center of the vehicle body.

  The cushion holder 106 has a holder main body 106a that is welded and joined to the lower side of the left and right central portion of the cross member 102 in a posture inclined along the inclined wall 102a, and an inclined front and lower side of the holder main body 106a so as to face the holder main body 106a. And a holder plate 106b that is integrally fastened in the above posture. Front and rear bosses 106c having screw holes are respectively fixed to the front and rear of the holder body 106a, and front and rear bolts 106d penetrating the front and rear of the holder plate 106b are screwed and tightened to the front and rear bosses 106c.

  Between the front and rear intermediate portions of the holder main body 106a and the holder plate 106b, a space having a substantially square shape in side view along these inclinations is formed, and a cushion rubber 104 having a substantially rectangular shape in side view is accommodated and sandwiched in the space. The The cushion holder 106 is provided so as to be located behind and substantially below the pivot axis C5 along the left-right direction, and project only below the swing arm 11 in a side view.

  The cushion rubber 104 penetrates the load input plate 107 on the holder main body 106a side (upper side), and a cutout hole 104a is formed on the cushion plate side (lower side) penetrating left and right. Since the lower portion of the load input plate 107 in the cushion rubber 104 is secured to be thicker than the upper portion of the load input plate 107, and the lower portion is also formed with a lightening hole 104a, Elastic deformation is positively allowed. In addition, as long as the said hollow hole 104a promotes the elastic deformation | transformation of the cushion rubber | gum 104, the shape, quantity, etc. will not ask | require and a recessed part etc. may be sufficient instead of a through-hole.

  The left and right end portions of the load input plate 107 protrude to the left and right outer sides of the cushion rubber 104 and the cushion holder 106, and the left and right end portions are respectively fastened to the rear end portion (upper end portion) of the rearward extension portion 95 a of the left and right under bracket 95. . Left and right bosses 95c having screw holes are fixed to the rear end portions of the left and right rearward extending portions 95a, and left and right bolts 95d penetrating the left and right end portions of the load input plate 107 are screwed to the left and right bosses 95c. Is included. The left and right rearward extending portions 95a are provided to be displaced to the left and right inside with respect to the periphery of the fastened portion 84a fastened to the crankcase 18 (see FIG. 16). Concave portions 102c and 106e for securing a space for attaching and detaching the left and right bolts 95d are respectively formed on the rear edge portion of the cross member 102 and the left and right side edge portions of the cushion holder 106 (holder body 106a) (see FIG. 15).

  When the swing arm 11 swings upward with respect to the vehicle body together with the rear wheel 9, the cushion rubber 104 pivots upward about the pivot axis C5 with respect to the load input plate 107, and the load input plate on the cushion rubber 104 The lower part of 107 is compressed and elastically deformed. At this time, the elastic force generated in the cushion rubber 104 becomes a reaction force (cushion load) against the swing of the swing arm 11 and the rear wheel 9. If the swing arm 11 swings downward with respect to the vehicle body due to the rear wheel 9 being separated from the ground or the like, a compressive load acts on the upper portion of the load input plate 107 in the cushion rubber 104. Since the upper part is relatively thin and does not positively allow elastic deformation, the part functions as a stopper rubber when the swing arm 11 swings downward.

Referring to FIGS. 14 and 15, a single damper 108 separate from the rear cushion 105 is provided on the swing base end side of the swing arm 11 and at a portion offset to the right side, for example, from the lateral center position.
The damper 108 is a rod type that is inclined so that its upper part is located on the front side, and upper and lower connecting parts 108 a and 108 b each having a spherical bearing are provided on the upper and lower ends, respectively.

  A lower damper support bracket 101a is welded to the lower side of the front portion of the right arm 101 of the swing arm 11, and the lower connecting portion 108b is fastened to the lower damper support bracket 101a by bolts 101b extending in the left-right direction. A lower end portion is slidably connected to the lower side of the front portion of the right arm 101. On the other hand, an upper damper support portion 12k is formed on the lower side of the front portion of the right rear frame body 12, and the upper connecting portion 108a is fastened to the upper damper support portion 12k by bolts 12l extending in the left-right direction. The part is connected to the lower side of the front part of the right rear frame body 12 so as to be swingable. The lower damper support bracket 101a is positioned behind and below the cross member 102 in a side view, and the upper damper support portion 12k is positioned substantially vertically above the cross member 102 in a side view.

  The damper 108 expands and contracts as the swing arm 11 swings, whereby the deformation energy of the cushion rubber 104 of the rear cushion 105 is attenuated and absorbed. The swing arm 11, the rear cushion 105, and the damper 108 mainly constitute the rear wheel suspension system RS. The damper 108 does not have a reaction force against the compression displacement, but it may have a predetermined compression displacement reaction force due to a compressive fluid or the like.

  As described above, the rear suspension structure of the saddle-ride type vehicle in the above embodiment is applied to the motorcycle 1 that swings the swing arm 11 for suspension of the rear wheels separately from the engine 16. A pivot portion 60 for supporting the swing arm 11 is provided at the rear end portion of the crankcase 18 of the engine 16, and an under bracket 95 is attached below the pivot portion 60 in the crankcase 18. A rear extension portion 95a extending rearward of the pivot portion 60 and in the vicinity of the swing arm 11 is provided at the rear portion, and a rear cushion 105 using a cushion rubber 104 between the rear extension portion 95a and the swing arm 11 is provided. Is provided.

According to this configuration, the swing arm 11 is supported by the crankcase 18 of the engine 16, thereby eliminating the pivot frame for supporting the swing arm 11 and reducing the weight of the vehicle body. It can be received by the engine 16.
Further, by adopting the rear cushion 105 using the cushion rubber 104, the rear suspension can be made lighter and more compact than when the rear cushion 105 using the metal spring is adopted.
Further, a rear extension 95a extending to the swing arm 11 side (under the spring) is provided on the under bracket 95 attached to the engine 16 side (on the spring), and a rear cushion is provided between the rear extension portion 95a and the swing arm 11. By providing 105, it is possible to reduce the weight of the swing arm 11 and the unsprung weight compared to the case where an extension portion extending to the engine 16 side is provided on the swing arm 11 side, and the rear extension portion. By making 95a (under bracket 95) separate from the crankcase 18, the crankcase 18 can be formed easily.
In addition, the cushion load input to the rear frame 2R at the rear of the vehicle body can be eliminated, and the rear frame 2R can be reduced in weight and size.

  In the rear suspension structure, the swing arm 11 includes a cross member 102 that connects the front portions of the left and right arms 101, and a cushion holder 106 that holds the outer periphery of the cushion rubber 104 is provided on the cross member 102. The under bracket 95 is provided with a load input plate 107 penetrating the cushion rubber 104, so that when the swing arm 11 swings up and down with respect to the vehicle body (engine 16) together with the rear wheel 9, the vehicle body The load input plate 107 provided on the side (under bracket 95) is relatively displaced with respect to the cushion rubber 104 held on the swing arm 11 side, and the load input plate 107 elastically deforms the rubber layer of the adjacent cushion rubber 104. In this manner, the rear cushion 105 that generates the elastic force of the cushion rubber 104 as a cushion load can be configured relatively easily.

Further, in the rear suspension structure, the rear frame 2R for supporting the passenger seating seat 13 is fastened and supported above the pivot portion 60 in the rear portion of the crankcase 18, and upper and rear fastening for fastening the rear frame 2R is performed. Since the portion 83 is provided in the vicinity of the pivot portion 60, the upper rear fastening portion 83 is provided in the vicinity of the pivot portion 60 in which strength and rigidity are ensured, and the upper rear fastening portion is not particularly required to be reinforced. The strength and rigidity of 83 can be easily secured.
Further, by providing the upper rear fastening portion 83 at a position above the pivot portion 60 in the rear portion of the crankcase 18, interference between the upper rear fastening portion 83 and the under bracket 95, the rear frame 2R, the swing arm 11, and the like. Can be efficiently avoided.

Furthermore, in the rear suspension structure, the damper 108 (energy absorbing device) is generated by providing the damper 108 that absorbs the swing energy of the swing arm 11 between the rear frame 2R and the swing arm 11. By distributing the damping force and the cushion load generated by the rear cushion 105 to the rear frame 2R and the under bracket 95, the rear frame 2R and the under bracket 95 can be reduced in weight and size.
Further, it is not necessary to give the cushion rubber 104 damping characteristics, and heat generation of the cushion rubber 104 can be suppressed and durability can be improved.

  The present invention is not limited to the above embodiment. For example, the connecting portion (upper damper support portion 12k) of the damper 108 to the rear frame 2R is provided in the vicinity of the upper rear fastening portion 83. May be. According to this configuration, by providing the connecting portion of the damper 108 in the vicinity of the fastened portion 83a for the upper rear fastening portion 83 in the rear frame 2R, it is particularly reinforced by utilizing the strength and rigidity of the fastened portion 83a. Therefore, it is possible to easily ensure the strength and rigidity of the connecting portion.

Further, for example, the front frame 2F and the left and right rear frame main bodies 12 are not limited to integral casting products using aluminum alloys, but are a plurality of cast (or forged) molded products, press molded products, extruded materials, pipe materials, and the like. These may be combined as appropriate and integrated by welding or the like. In addition to aluminum alloys, various mechanical materials such as steel materials such as steel and cast iron, non-ferrous metal materials such as magnesium alloys and titanium alloys, and composite materials such as FRP may be used.
Further, the front frame 2F and the rear frame 2R may be fastened and supported to the engine 16 by fasteners other than the long bolts 80b to 84b and the nuts 80c to 84c. Further, the rear frame 2R may be fastened and supported to the front frame 2F (main frame).
And the structure in the said Example is an example of this invention, It can apply not only to a motorcycle but to a scooter type vehicle which has a three-wheel or a four-wheel vehicle, and a floor step, In the range which does not deviate from the summary of the said invention. It goes without saying that various modifications are possible.

1 is a left side view of a motorcycle according to an embodiment of the present invention. Fig. 2 is a left side view including a partial cross section of the engine of the motorcycle. It is an expanded sectional view in alignment with the crankshaft line of the above-mentioned engine. It is a left view which shows the fastening part of the front part of the said engine, and the rear part of a front frame. It is A arrow directional view of FIG. It is BB sectional drawing of FIG. It is a left view equivalent to FIG. 4 which shows the modification of the fastening structure of the said engine and a front frame. It is CC sectional drawing of FIG. Fig. 3 is a left side view of a fuel tank supported by a rear frame of the motorcycle. It is a top view of the fuel tank. It is DD sectional drawing of FIG. It is EE sectional drawing of FIG. FIG. 12 is a cross-sectional view corresponding to FIG. 11 showing a modification of the fuel tank. It is a left view which shows the fastening part of the rear part of the said engine and the front part of a rear frame, a rear-wheel suspension system, etc. It is explanatory drawing which looked at the principal part of the said rear-wheel suspension system planarly. It is FF sectional drawing of FIG. It is GG sectional drawing of FIG.

Explanation of symbols

1 Motorcycle 2R Rear frame 11 Swing arm 12k Upper damper support part (connection part)
13 Seat 16 Engine 18 Crankcase 60 Pivot part 82 Center rear fastening part (rear fastening part)
83 Upper rear fastening part (rear fastening part)
95 Under bracket 95a Rear extension part 101 Left and right arm 102 Cross member 104 Cushion rubber 105 Rear cushion 106 Cushion holder 107 Load input plate (load input member)
108 damper

Claims (5)

In the rear suspension structure of a saddle-ride type vehicle that swings a swing arm for suspension of a rear wheel separately from an engine,
A pivot portion for supporting the swing arm is provided at a rear end portion of the crankcase of the engine, an under bracket is attached below the pivot portion in the crankcase, and a rear portion of the under bracket is more than the pivot portion. A rear suspension for a saddle-ride type vehicle, characterized in that a rear extension portion extending rearward and near the swing arm is provided, and a rear cushion using a cushion rubber is provided between the rear extension portion and the swing arm. Construction.   The swing arm includes a cross member that connects between the front portions of the left and right arms, the cross member is provided with a cushion holder that holds an outer periphery of the cushion rubber, and the under bracket penetrates the cushion rubber. The rear suspension structure for a saddle-ride type vehicle according to claim 1, further comprising a load input member for performing the saddle riding type vehicle.   A rear frame that supports an occupant seat is fastened and supported above the pivot portion at the rear portion of the crankcase, and at least one of the rear fastening portions for fastening the rear frame is provided in the vicinity of the pivot portion. The rear suspension structure of a saddle-ride type vehicle according to claim 1 or 2, wherein   The rear suspension structure for a saddle-ride type vehicle according to claim 3, wherein a damper for absorbing swing energy of the swing arm is provided between the rear frame and the swing arm. The rear suspension structure for a saddle-ride type vehicle according to claim 4, wherein a connecting portion of the damper to the rear frame is provided in the vicinity of at least one of the rear fastening portions.

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