JP2004123062A - Rear fork structure of motorcycle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make axle supporting members as small as practicable and to firmly couple a rear fork with each axle supporting member, in a constitution where a lower coupling part to couple the bottom part of a rear cushion unit is integrally formed with the axle supporting member of a rear fork. <P>SOLUTION: The rear fork 34 of the motorcycle 10 is equipped with axle supporting members 84 at the tails of a left 81 a right arm 81 extending fore and aft. Each axle supporting member has a supporting hole 85 to support an axle 121 for a rear wheel, and the lower coupling part 86 to couple a bottom part 102 of the rear cushion unit 36 is extended upward from the front upper part more than the supporting hole, and the front end part 87 of the axle supporting member is located in the neighborhood of and ahead of the lower coupling part, and a joining surface 89 inclining down backward is formed in the front end part. Also at the tail of the left and right arms, a joining surface 97 inclining down backward is formed. The left and right arms and the left and right axle supporting members can be integrally constructed by overlapping joining the joining surfaces. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique for improving a rear fork structure of a motorcycle.
[0002]
[Prior art]
BACKGROUND ART In a motorcycle, a rear suspension device in which a rear wheel is mounted on a rear fork supported by a body frame is known (for example, see Patent Literature 1 and Patent Literature 2).
[0003]
[Patent Document 1]
JP-A-5-193545 (page 2, FIG. 1)
[Patent Document 2]
JP-A-2001-1977 (page 3-4, FIG. 1-2)
[0004]
According to Patent Literature 1, the conventional rear fork includes a lower connecting portion that bridges a cross member between front portions of left and right arms extending in a front-rear direction, and connects a lower end portion of a rear cushion unit to the cross member. Then, axle brackets are welded to the rear ends of the left and right arms, respectively, and the axle for the rear wheel is supported by these axle brackets.
[0005]
According to Patent Literature 2, the conventional rear suspension device mounts a front end of a rear fork on a vehicle body frame so as to be able to swing up and down, and suspends a rear portion of the rear fork on a vehicle body frame via a rear cushion unit. is there. The rear fork includes a lower connecting portion that connects a lower end portion of the rear cushion unit at a rear portion, and a support hole that supports a rear wheel axle.
[0006]
[Problems to be solved by the invention]
By the way, the position of the lower connecting portion connecting the lower end portion of the rear cushion unit is set in consideration of the load balance of the entire motorcycle, the cushion performance of the rear cushion unit, and the like.
In Patent Document 1, a lower connecting portion is provided at a front portion of a rear fork. However, as in Patent Document 2, a lower connecting portion may be provided at a rear portion of the rear fork. In that case, in the rear fork of Patent Literature 1, a lower connection portion having a relatively complicated shape is integrally formed on an axle bracket (corresponding to an axle support member). However, simply forming the lower connection portion integrally increases the size of the axle bracket. Therefore, when a large axle metal fitting is a forged product or a cast product, the molding die becomes large and the manufacturing cost increases.
Also, if the lower connecting part is formed integrally with the axle bracket, it is necessary to have sufficient strength to receive the load from the rear cushion unit and the axle, and to improve the coupling strength between the rear fork and the axle bracket, And the axle bracket itself had to be enlarged.
[0007]
Therefore, an object of the present invention is to reduce the size of the axle support member as much as possible while providing the lower connecting portion for connecting the lower end portion of the rear cushion unit integrally with the axle support member of the rear fork. It is an object of the present invention to provide a technique capable of firmly joining a member.
[0008]
[Means for Solving the Problems]
To achieve the above object, a first aspect of the present invention is to attach a front end of a rear fork for a rear wheel to a body frame so as to be able to swing up and down, and to suspend a rear portion of the rear fork for the rear wheel on the body frame via a rear cushion unit. Motorcycle,
The rear fork has axle support members at the rear ends of the left and right arms extending forward and backward, respectively.
The axle support member includes a support hole for supporting the rear wheel axle, and extends a lower connecting portion connecting the lower end portion of the rear cushion unit upward from the front upper portion to the upper side of the support hole. A front end portion of the axle support member is provided in the front, and a joining surface inclined downward and downward is provided at the front end portion,
The right and left arms and the left and right axle support members are integrally formed by providing a joint surface that slopes backward and downward at the rear ends of the left and right arms, and by joining these joint surfaces together. It is a rear fork structure of a motorcycle characterized by the following.
[0009]
The rear fork is divided into left and right arms and an axle support member, and these are joined together. A front end portion of the axle support member is provided near and forward of a lower connecting portion provided on the axle support member. The axle support member is provided despite the complicated shape in which the lower connection portion is provided on the axle support member because the joint surface inclined backward and downward is provided and the inclined joint surfaces are overlapped and joined. Can be made as small as possible. For this reason, when the axle support member is a forged product or a cast product, the molding die can be downsized, and the manufacturing cost can be reduced.
Moreover, the structure of the axle support member can be simplified, and the weight can be reduced.
Further, since the inclined joining surfaces are overlapped and joined by welding or the like, the joining length can be increased. As a result, the joining strength between the rear fork and the axle support member can be further increased.
[0010]
According to a second aspect of the present invention, the support hole, the lower connecting portion, and the upper connecting portion connecting the upper end portion of the rear cushion unit to the vehicle body frame are arranged substantially on a straight line.
The load can be efficiently transmitted between the rear wheel axle and the lower connecting portion.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that “front”, “rear”, “left”, “right”, “up”, and “down” follow directions viewed from the driver. Also, the drawings should be viewed in the direction of reference numerals.
[0012]
FIG. 1 is a left side view of a motorcycle according to the present invention. The motorcycle 10 has a front fork 12 attached to a head pipe 11 so as to be steerable, a steering handle 14 attached to a top bridge 13 of the front fork 12, and a front bracket between the top bridge 13 and the bottom bridge 15 via a bracket. A headlight 16, a front blinker 17, and meters 18 are attached, a front fender 19 and a front wheel 21 are attached below the front fork 12, a main frame 22 as a body frame is extended rearward from the head pipe 11, and a down tube is attached. 23 is extended obliquely downward from the rear, an engine 24 is interposed between the main frame 22 and the down tube 23, and power is taken out of the engine 24 by a driving sprocket 25, a chain 26 and a driven sprocket 27, and The gin 24 is held on the body frame, the seat rail 28 is extended rearward from the main frame 22, the fuel tank 29 and the tandem seat 31 are placed in this order, and the sub-frame 32 is extended from the down tube 23 to the seat rail 28. A rear fork 34 is extended from a lower rear portion of the body frame via a pivot 33, and a rear wheel 35 is rotatably attached to the rear end of the rear fork 34. The rear portion of the rear fork 34 and the body frame (the subframe 32 and the seat rail 28 The rear cushion unit 36 is provided between the rear cushion unit 36 and the corner.
[0013]
The combination structure of the head pipe 11, the main frame 22, the down tube 23, the seat rail 28, and the sub-frame 32 forms a body frame 60.
A mechanism for attaching the rear wheel 35 to the body frame 60 by the rear fork 34 and the rear cushion unit 36 is a rear suspension device 70.
The rear wheels 35 can be driven by the power taken out of the engine 24 by the chain 26.
[0014]
41 is a radiator, 42 is an air cleaner, 43 is a throttle valve, 44 is a cylinder head, 45 is an exhaust pipe, 46 is a main stand, 47 is a silencer, 48 is a rear fender, 49 is a license light, 51 is a rear blinker, 52 is a rear cowl, 53 Is a club rail, and 54 is a tail light.
[0015]
FIG. 2 is an enlarged view of the periphery of the rear suspension device according to the present invention. The front end of the rear fork 34 is attached to the vehicle body frame 60 so as to be able to swing up and down, and the rear portion of the rear fork 34 is (Only the left side is shown in the figure).
[0016]
The vehicle body frame 60 has a lower bracket 61 attached to a lower rear portion, that is, a corner portion where the rear end of the main frame 22 is joined to the subframe 32, and a corner where the rear upper end of the subframe 32 is joined to the rear upper portion, that is, the seat rail 28. The upper connecting portion 62 is attached to the portion.
[0017]
The support tube 83 at the front end of the rear fork 34 can be attached to the lower bracket 61 so as to be able to swing up and down by the pivot 33. On the other hand, the upper end portions 101 of the left and right rear cushion units 36 can be connected to the upper connecting portion 62 by a pivot 63 so as to be able to swing back and forth. Thus, the front end of the rear fork 34 and the upper ends 101 of the left and right rear cushion units 36 are connected to the vehicle body frame 60.
The rear fork 34 includes a lower connecting portion 86 that connects the lower end portion 102 of the rear cushion unit 36 to be able to swing back and forth by a pivot 111.
[0018]
Next, the configuration of the rear fork 34 will be described. 3 is a left side view of the rear fork according to the present invention, FIG. 4 is a plan view of the rear fork according to the present invention, FIG. 5 is a sectional view taken along line 5-5 in FIG. 3, and FIG. It is an exploded view.
[0019]
The rear fork 34 is a swing arm having a substantially H-shape in plan view, which includes left and right arms 81, 81 extending in the front-rear direction, and a cross member 82 bridged between intermediate portions of the arms 81, 81. The left and right arms 81, 81 have a support tube 83 suspended between the front ends thereof, and have axle support members 84, 84 at the rear ends, respectively.
[0020]
The left and right axle support members 84, 84 each have a support hole 85 penetrating in the vehicle width direction, extend the lower connecting portion 86 upward from the front upper part of the support hole 85, and extend near the lower connecting portion 86 and forward ( A left end portion of the axle support member 84 is provided on the left side in FIGS. 3 and 4), and a joining surface 89 is provided on the front end portion 87 so as to be inclined backward and downward, and is made of a forged product or a cast product.
[0021]
The support holes 85 are elongated holes before and after supporting the rear wheel axle 121 (see FIG. 2).
As shown in FIGS. 4 and 5, the lower connecting portion 86 has a fork shape (bifurcated shape) whose upper side is open in rear view, and has left and right connecting piece portions 91 and 92 arranged with a constant gap Sp. Consists of These left and right connecting pieces 91 and 92 have connecting holes 91a and 92a penetrating in the vehicle width direction.
[0022]
As shown in FIG. 6, a front end portion 87 of the axle support member 84 is a portion that is provided near and in front of the lower connecting portion 86 and that slopes downward and is a hole at the rear end of the arm 81 made of a pipe material. And a joint surface 89 (flange surface 89) formed between the fitting convex portion 88 and the lower connecting portion 86. The joining surface 89 is an inclined surface having substantially the same inclination angle as the front end portion 87.
[0023]
Since the lower connecting portion 86 is disposed in the upper front portion of the axle support member 84, the front end portion 87 and the joining surface 89 immediately before the lower connecting portion 86 can be inclined backward and downward. As a result of inclining backward, there is no front lower portion 94 shown by the imaginary line in FIG. 6 among the axle support members 84, so that the axle support members 84 can be reduced in size and weight accordingly.
[0024]
The left and right arms 81, 81 are pipes provided with a joining surface 97 inclined rearward and downward at a rear end portion 96. The inclination angle of the joint surface 97 of the arm 81 is the same as the inclination angle of the joint surface 89 of the axle support member 84.
The joining surfaces 97, 97 of the left and right arms 81, 81 and the joining surfaces 89, 89 of the left and right axle support members 84, 84 are overlapped and joined by welding or the like, so that the left and right arms 81, 81 and the left and right arms 81, 81 are joined together. The axle support members 84, 84 can be integrally formed.
[0025]
Here, description will be made with reference to FIG. FIG. 2 shows a support hole 85 that supports the axle 121, a lower connecting portion 86 that connects the lower end 102 of the rear cushion unit 36 to the axle support member 84, and an upper end 101 of the rear cushion unit 36 that is connected to the body frame 60. The upper connecting portion 62 and the upper connecting portion 62 are arranged on a substantially straight line L1.
[0026]
That is, the axle 121, the pivot 111 on the lower connecting portion 86 side, and the pivot 63 on the upper connecting portion 62 side are arranged on a substantially straight line L1. In this manner, the position of the support hole 85 can be made substantially coincident with the straight line L1 passing through the longitudinal axis of the rear cushion unit 36. The joint surface 89 of the axle support member 84 is substantially parallel to the straight line L1.
[0027]
FIG. 7 is a sectional view of a main part on the left side of the rear suspension device as viewed from the rear. An axle 121 made of a pipe material is fitted into a support hole 85 of a left axle support member 84, and a bolt 122 is passed through the axle 121. This shows that the hub 35a of the rear wheel 35 is rotatably mounted on the axle 121 by being attached to the support member 84.
[0028]
Further, FIG. 7 shows a detailed configuration in which the lower end portion 102 of the rear cushion unit 36 is connected to the lower connecting portion 86 by a pivot 111.
The pivot 111 is formed of a hexagon socket head bolt, and the head 112 of the bolt is fitted into the connection hole 91 a of the one connection piece 91, and the shaft 113 of the bolt is fitted into the connection hole 92 a of the other connection piece 92. The nuts 114 protrude and are screwed into the nuts 114.
Furthermore, the head 112 of the bolt is fitted into the connection hole 91a of the one connection piece 91, and the end of the head 112 is prevented from protruding from the connection piece 91 in the vehicle width direction (the longitudinal direction of the bolt). did. Since the head 112 does not protrude, the rear suspension device 70 can be narrowed in the vehicle width direction.
[0029]
The lower end portion 102 of the rear cushion unit 36 includes a rotating ring 103 (inner ring 103) rotatable about a swing center. The rotating ring 103 is interposed in the gap Sp between the left and right connecting pieces 91 and 92, and the shaft 113 of the pivot 111 is fitted to the rotating ring 103 so that the lower end 102 of the rear cushion unit 36 can be pivoted. The lower connecting portion 86 can be connected to the lower connecting portion 86 through a swingable manner.
[0030]
The other connecting piece 92 and the head 112 of the pivot 111 gently sandwich both end faces of the rotating ring 103 in the axial direction. Further, by supporting both ends of the pivot 111 with the left and right connecting pieces 91 and 92, a both-ends support structure can be obtained. Since the pivot 111 is supported by the both-ends support structure, the rigidity of the pivot 111 and the connecting pieces 91 and 92 can be further increased.
[0031]
Here, the above description will be described collectively.
The rear fork 34 is divided into left and right arms 81, 81 and axle support members 84, 84, and these are joined to each other, and near and forward of lower connecting portions 86, 86 provided on the axle support members 84, 84. The front end portions 87, 87 of the axle support members 84, 84 are provided, and the front end portions 87, 87 are provided with joining surfaces 89, 89 inclined rearward and downward. The rear end portions 96, 96 of the left and right arms 81, 81 are also provided with joining surfaces 97, 97 inclined rearward and downward.
[0032]
Since these joining surfaces 89, 97 are overlapped and joined, the axle supporting members 84, 84 have a complicated shape in which the lower connecting portions 86, 86 are provided on the axle supporting members 84, 84, despite the complicated shape. 84 can be made as small as possible. For this reason, when the axle support members 84 and 84 are forged products or cast products, the size of the molding die can be reduced, and the manufacturing cost can be reduced.
[0033]
Moreover, the structure of the axle support members 84, 84 can be simplified, and the weight can be reduced.
Furthermore, since the inclined joining surfaces 89 and 97 are overlapped and joined by welding or the like, the joining length can be increased. As a result, the joining strength between the joining surfaces 89 and 97 can be further increased.
[0034]
Furthermore, as shown in FIG. 2, the support hole 85, the lower connecting portion 86, and the upper connecting portion 62 are arranged on the substantially straight line L <b> 1, so that the rear wheel axle 121 and the lower connecting portion 86 can be located between the rear wheel axle 121 and the lower connecting portion 86. Thus, the load can be transmitted efficiently.
In particular, the compression load from the motorcycle 10 and the compression load due to the road surface reaction force can be efficiently transmitted between the axle 121, the lower connecting portion 86, the rear cushion unit 36, and the upper connecting portion 62. As a result, the cushion performance of the rear cushion unit 36 can be efficiently exhibited.
[0035]
【The invention's effect】
The present invention has the following effects by the above configuration.
According to a first aspect of the present invention, the rear fork is divided into left and right arms and an axle support member, which are joined together, and a front end portion of the axle support member is provided near and forward of a lower connecting portion provided on the axle support member. The front end portion is provided with a joining surface inclined downward and downward, and the inclined joining surfaces are overlapped and joined to each other, so that the axle support member is provided with a lower connecting portion, which is a complicated shape. Thus, the axle support member can be made as small as possible. For this reason, when the axle support member is a forged product or a cast product, the molding die can be downsized, and the manufacturing cost can be reduced.
Moreover, the structure of the axle support member can be simplified, and the weight can be reduced.
Further, since the inclined joining surfaces are overlapped and joined by welding or the like, the joining length can be increased. As a result, the joining strength between the rear fork and the axle support member can be further increased.
[0036]
According to a second aspect of the present invention, the support hole, the lower connecting portion, and the upper connecting portion connecting the upper end of the rear cushion unit to the vehicle body frame are arranged substantially on a straight line. , The load can be transmitted efficiently.
[Brief description of the drawings]
FIG. 1 is a left side view of a motorcycle according to the present invention; FIG. 2 is an enlarged view around a rear suspension device according to the present invention; FIG. 3 is a left side view of a rear fork according to the present invention; FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. 3; FIG. 6 is an exploded view of the rear fork according to the present invention; FIG. [Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... motorcycle, 34 ... rear fork, 35 ... rear wheel, 36 ... rear cushion unit, 60 ... body frame, 62 ... upper connection part, 81 ... arm, 84 ... axle support member, 85 ... support hole, 86 ... lower part Connecting portion, 87: front end of axle support member, 89: joining surface, 96: rear end of arm, 97: joining surface, 101: upper end of rear cushion unit, 102: lower end of rear cushion unit, 111 ... Pivot, 121: rear wheel axle, L1: straight line.

Claims (2)

A motorcycle in which a front end of a rear fork for a rear wheel is attached to a body frame so as to be able to swing up and down, and a rear portion of the rear fork for the rear wheel is suspended from the body frame via a rear cushion unit.
The rear fork includes axle support members at rear ends of left and right arms extending forward and backward, respectively.
The axle support member includes a support hole for supporting a rear wheel axle, and a lower connecting portion connecting a lower end portion of the rear cushion unit extends upward from a front upper portion to the upper side of the support hole. A front end portion of the axle support member is provided in the vicinity and forward of the axle support member, and a joining surface inclined downward and downward is provided at the front end portion,
The left and right arms and the left and right axle support members are integrally formed by providing a joining surface inclined rearward and downward at the rear end portions of the left and right arms, and by joining these joining surfaces together. The rear fork structure of a motorcycle characterized by the following. The motorcycle according to claim 1, wherein the support hole, the lower connecting portion, and an upper connecting portion connecting an upper end portion of the rear cushion unit to the vehicle body frame are arranged substantially on a straight line. Rear fork structure.

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