JP2003011876A - Rear arm for motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the weight of a rear arm 10 in the form of a chevron on side view. SOLUTION: An arm 22 which adjoins to an exhaust pipe (silencer 13 and downstream exhaust pipe 14) is formed of a lower arm supporting the axle of a rear wheel 9 against its rear end portion and an upper arm 34 extending forwardly upwardly from the upper surface of the rear end portion of the lower arm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has left and right arms extending from a base for connecting a pivot shaft to both sides of a rear wheel.
The present invention relates to a rear arm for a motorcycle, which is formed in a V shape when viewed from the side where an exhaust pipe is located.

[0002]

2. Description of the Related Art A conventional rear arm for a motorcycle is provided with left and right arms that extend laterally in the front-rear direction on the side of a rear wheel, and a base for connecting a pivot shaft that connects the front ends of these arms. There is one in which one arm adjacent to the pipe is formed in a V shape in a side view so as to avoid interference with the exhaust pipe. The V-shaped arm in a side view of this type of rear arm is formed into a rectangular tube shape by welding the outer half of the vehicle body and the inner half of the vehicle body to each other. The arm on the other side includes a lower arm linearly extending from the base toward the rear of the vehicle body and an upper arm extending from the upper surface of the rear end of the lower arm to the front and extending to the upper extension of the base. It is composed of an arm. This upper arm is often formed by a square pipe. The uppermost portion of the upper arm and the uppermost portion of the V-shaped arm are connected to each other via the upwardly extending portion of the base portion in order to maintain rigidity.

[0003]

However, when the V-shaped arm in side view is formed by the outer half of the vehicle body and the inner half of the vehicle body as described above, there is a problem that the weight becomes heavy. This is because the V-shaped arm is formed so that the uppermost part of the V-shaped arm and the uppermost part of the upper arm of the other arm are located at substantially the same height.
That is, the plate-shaped portion of the V-shaped arm is elongated in the vertical direction.

The present invention has been made to solve such a problem, and an object thereof is to reduce the weight of a V-shaped rear arm in a side view.

[0005]

In order to achieve this object, a rear arm for a motorcycle according to the present invention is a rear arm for a motorcycle formed in a V shape when viewed from the side where an exhaust pipe is located, The arm adjacent to the exhaust pipe is formed by a lower arm that supports the axle of the rear wheel at the rear end and an upper arm that extends upward from the upper surface of the rear end of the lower arm. According to the present invention, when connecting the uppermost parts of the left and right arms in order to improve the rigidity of the rear arm, the upper end part of the upper arm of the arm adjacent to the exhaust pipe can be connected to the other arm. That is,
Since the arm adjacent to the exhaust pipe can form a space between the lower arm and the uppermost portion, it is possible to reduce the plate-shaped portion extending in the vertical direction as compared with the conventional case.

A rear arm for a motorcycle according to a second aspect of the present invention is the rear arm for a motorcycle according to the first aspect, wherein the lower arm of the arm adjacent to the exhaust pipe is the rear end of the lower arm body. The rear end of the upper arm is joined to the lower arm main body and the end portion. According to the present invention, since the load is transmitted from both the lower arm body and the end portion to the upper arm, it is possible to reduce the stress in the shearing direction generated in the welded portion between the lower arm body and the end portion.

A rear arm for a motorcycle according to a third aspect of the present invention is the rear arm for a motorcycle according to the first aspect of the present invention, wherein the upper arm is connected to the top of the base at the front and curved rearward. And is connected to the upper surface of the rear end of the other arm. According to the present invention, the left and right arms can be connected by the upper arm, and the upper arm functions as a cross member.

A rear arm for a motorcycle according to a fourth aspect of the present invention is the rear arm for a motorcycle according to the first aspect, wherein the lower arm of the arm adjacent to the exhaust pipe is welded to the inner and outer two panels. It has been configured. According to the present invention, as compared with the case where the lower arm is formed by extrusion, for example, the portion that requires relatively high rigidity may be formed to have a large cross-sectional area and the rigidity may be relatively low. The part can be formed so that the cross-sectional area becomes small and the weight can be reduced.
Therefore, the degree of freedom in designing the cross-sectional shape of the lower arm is increased.

A rear arm for a motorcycle according to a fifth aspect of the present invention is a rear arm for a motorcycle according to the first aspect of the present invention, wherein the rear arm is provided in a space formed between a lower arm and an upper arm. It goes through the hydraulic hose of the brake. According to the present invention, the upper arm functions as a protective cover that covers the hydraulic hose from above.

A rear arm for a motorcycle according to a sixth aspect of the present invention is the rear arm for a motorcycle according to the fifth aspect, wherein the rear brake caliper is disposed above the rear axle. According to this invention,
Since the rear brake caliper is arranged above the lower arm, the hydraulic hose connected between the lower arm and the upper arm can be connected to the rear brake caliper without being greatly bent.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a rear arm for a motorcycle according to the present invention will be described in detail below with reference to FIGS. 1 is a side view of a motorcycle using a rear arm according to the present invention, FIG. 2 is a right side view of an essential part, FIG. 3 is a view showing a rear arm, FIG. 1 (a) is a plan view, and FIG. The right side view and the same figure (c) are left side views. FIG. 4 is a sectional view taken along line IV-IV of the lower arm in FIG.
FIG. 5 is a sectional view taken along line VV in FIG. 2. FIG. 6 is an enlarged side view showing the exhaust control valve portion of the exhaust device, and FIG. 7 is a rear view of the motor mounting portion, in which the portion supporting the downstream side exhaust pipe is cut away. The position of this break is indicated by line VII-VII in FIG. Figure 8 is a side view of the motor,
In the figure, the portion attached to the vehicle body frame is drawn in a broken state.

In these figures, the reference numeral 1 designates a motorcycle according to this embodiment. 2 shows a body frame of the motorcycle 1, 3 shows an engine, 4
Is a front wheel, 5 is a front fork, 6 is a steering wheel, 7
Is a fuel tank, 8 is a seat, 9 is a rear wheel, and 10 is a rear arm that supports the rear wheel 9.

The engine 3 of this motorcycle 1 is of a water-cooled 4-cycle 4-cylinder type and is connected to a driven sprocket 9a provided on the left side of the rear wheel 9 via a drive chain (not shown). The rear wheels 9 are driven by this drive chain. Further, the exhaust system 11 of the engine 3 has upstream exhaust pipes 11a (see FIG. 6) for each cylinder gathered below the engine 3, and an exhaust control valve 11b (see FIG. 6) is provided at this gathering portion. Is.

The exhaust control valve 11b has a structure similar to that well known in the prior art, and a valve 12 is internally provided by a motor 12 (see FIG. 2) arranged below a front portion of a rear arm 10 which will be described later. Is driven to change the position where the pressure wave of the exhaust gas is reflected toward the engine 3. Motor 1
2, the exhaust control valve 11b is driven by two wires 12a as shown in FIG. The wire 12a and the pulley (not shown) of the exhaust control valve 11b connecting the wire 12a are arranged on the right side of the vehicle body so that the wire length is as short as possible. At the downstream end of the exhaust control valve 11b, a silencer 13 extending rearward and upward on the right side of the rear wheel 9 (see FIG. 2).
(Refer to FIG. 4) is connected by the downstream side exhaust pipe 14.

The rear arm 10 of the motorcycle 1 is, as shown in FIG. 3 (a), the left side of the vehicle body (upper side in the figure).
The rear wheel 9 is supported by the arm 21 of the vehicle body 2 and the arm 22 on the right side of the vehicle body, and the base portion 23 connecting the front end portions of the two arms 21 and 22 is attached to the rear arm bracket 2a of the vehicle body frame 2 by the pivot shaft 24 (see FIG. 1 and FIG. 2), and is swingably supported in the vertical direction. The material forming each member of the rear arm 10 is an aluminum alloy.

The base portion 23 is composed of a cylinder 25 through which the pivot shaft 24 penetrates, and a box-shaped portion 26 welded to the rear side of the cylinder 25. The box-shaped portion 26 is formed into a box shape having a substantially triangular shape in a side view by welding a plurality of plate materials. Further, a hollow portion 28 for inserting the rear cushion unit 27 (see FIG. 1) is formed in the center portion of the box-shaped portion 26 in the left-right direction. The rear cushion unit 27 has a lower end portion connected to a lower bracket 26a protruding from the lower surface of the box-shaped portion 26 via a link 29 (see FIG. 1), and an upper end portion that is a cushion unit bracket 2b of the vehicle body frame 2. (See FIG. 1).

The left and right arms 21 of the rear arm 10,
As shown in FIGS. 3 (b) and 3 (c), the reference numeral 22 denotes a lower arm 31, linearly extending rearward from the base 23,
32 and upper arms 33 and 34 extending upward from the upper surfaces of the rear ends of the lower arms 31 and 32. 3B and 3C, the arms on the opposite side in the left-right direction are omitted.

Lower arm 31 of arm 21 on the left side of the vehicle body
As shown in FIG. 3 (c), an end bracket 31b for mounting rear wheels is attached to the rear end of a rectangular pipe 31a having a rectangular cross section.
Are formed by welding, and the front end portion is welded to the box-shaped portion 26. A welding line at the front end of the lower arm 31 is indicated by reference numeral 35 in FIG. The upper arm 33 of the arm 21 on the left side of the vehicle body is formed of a square pipe, and the rear end portion is welded to the upper surface of the end bracket 31b.

In this embodiment, as shown in FIG. 3 (a), the upper arm 33 is formed in a U-shape that is open toward the rear of the vehicle body and the upper arm 3 of the arm 22 on the right side of the vehicle body is formed.
It is formed integrally with 4. In the upper arm thus formed in a U shape, the bent portion of the front end is welded to the upper rear end of the box-shaped portion 26 (the top of the base 23).

Lower arm 32 of arm 22 on the right side of the vehicle body
As shown in FIG. 3 (b) and FIG. 4, a half portion 32a on the inner side of the vehicle body and a half portion 32b on the outer side of the vehicle body formed in a U-shaped cross section.
And a pipe portion 32c welded to each other and a rear wheel mounting end bracket 32d welded to the rear end portion of the pipe portion 32c, and the front end portion is welded to the box-shaped portion 26. . This weld line is shown by reference numeral 36 in FIG. The pipe portion 32c constitutes the lower arm body according to the invention of claim 2, and the end bracket 3
2d constitutes the end portion. Further, the half portion 32a on the inner side of the vehicle body and the half portion 32b on the outer side of the vehicle body form two panels, the inner and outer panels according to the invention described in claim 4.

The upper arm 34 of the arm 22 on the right side of the vehicle body
Welds the rear end of the end bracket 32d to the upper surface of the end bracket 32d and the upper surface of the pipe portion 32c. In addition, the upper arm 34 is forwardly attached to the base portion 23.
The upper arm 33 of the left arm 21 of the vehicle body is connected to the upper surface of the rear end portion of the left arm 21 of the vehicle body. Further, as shown in FIG. 2, the upper arm 34 holds a hydraulic hose 42 of the rear wheel brake 41.

The hydraulic hose 42 is used for the rear wheel brake 4
No. 1 master cylinder 43 and the brake caliper 44 are connected, and the upper arm 34 is connected by the hose holder 45 and the clamp 46 attached to the upper arm 34.
To hold. The master cylinder 43 is attached to a footrest bracket 47 on the right side of the vehicle body, and is supported by the rear arm bracket 2a via the bracket 47. The footrest bracket 47 includes
A footrest 48 and a brake pedal 49 are provided.

The brake caliper 44 is arranged above the axle 9b of the rear wheel 9 and is mounted on the end bracket 32d together with the rear wheel 9 in a state where the rotation is restricted by the end bracket 32d. Reference numeral 50 provided in the vicinity of the brake caliper 44 is a brake disc of the rear wheel brake 41. As shown in FIG. 5, the hose holder 45 is formed into a shape that fits into the upper arm 34 from the inside of the vehicle body (the left side in the figure), and the upper end is fixed to the upper arm 34 by a rivet 51 and the lower end is fixed. Hooks 45 provided at two positions in the front-back direction of the section
The hydraulic hose 42 is engaged with a and 45b. The hooks 45a and 45b hold the hydraulic hose 42 along the lower surface of the upper arm 34 so as to be substantially parallel to the extending direction of the upper arm 34.

The clamp 46 is fixed to the inner wall of the vehicle body of the upper arm 34 and has an annular member through which the hydraulic hose 42 is inserted. These holder 45 and clamp 46
By holding the hydraulic hose 42 on the upper arm 34 by means of, the hydraulic hose 42 can be piped into the space S formed between the upper arm 34 and the lower arm 32. More specifically, the hydraulic hose 42 extends rearward from the master cylinder 43 along the right side surface of the box-shaped portion 26 of the rear arm 10 and enters the space S, and is halfway along the upper arm 34 by the hose holder 45. The position of the department is decided. The hydraulic hose 42 is led out from the space S to the inside of the vehicle body behind the hose holder 45, is held by a clamp 46, and is connected to the brake caliper 44.

Rear arm 10 constructed as described above
As shown in FIGS. 2 and 3B, is formed in a V shape when viewed from the right side where the exhaust pipes (silencer 13 and downstream exhaust pipe 14) are located. The V-shape is formed by the motor 12 that drives the exhaust control valve 11b.
Is under the front part of the rear arm 10 as shown in FIG.
This is to avoid interference between the motor 12 and the rear arm 10. As shown in FIGS. 2 and 3 (a), the motor 12 is disposed below the front end of the base portion 23 of the rear arm 10 on the right side of the vehicle body. As shown in FIG. 8, the motor 12 is laterally attached to the left and right rear arm brackets 2a. Cross member 2c hung
Are supported via brackets 12b.

The position of the motor 12 is as shown in FIGS.
As shown in, the exhaust control valve 11b and the silencer 1
A downstream side exhaust pipe 14 that connects the downstream side exhaust pipe 14 and the downstream side exhaust pipe 14 is connected under the motor 12 so that the downstream side exhaust pipe 14 does not heat the motor 12.
The motor 12 is set so as to be sufficiently separated from the above. The downstream exhaust pipe 14 extends below the cross member 2c in the front-rear direction and is supported by the cross member 2c by a supporting stay 14a and a bracket 14b. Since the lower exhaust pipe 14 that has a high temperature is located,
Avoiding the interference between the motor 12 and the rear arm 10, the motor 1
Since it is not possible to shift the position of 2 downwards because the motor 12 is damaged by heat, the rear arm 10 is formed in the V shape as described above, and a space for housing the motor is widened below the rear arm 10. Is forming. In this embodiment, the space for accommodating the motor 12 is widened by forming the lower surface 23a of the end portion on the right side of the vehicle body of the base portion 23 of the rear arm 10 above the lower surface 23b of the end portion on the left side of the vehicle body. .

The motor 12 is arranged below the end of the base portion 23 of the rear arm 10 on the right side of the vehicle body because the drive chains extend in the front-rear direction both above and below the arm 21 on the left side of the vehicle body. That is, it is not possible to form the left side of the vehicle body of the rear arm 10 in a side view as it is easy to contact the drive chain. Therefore, the motor 12 should be arranged below the end portion of the rear arm 10 on the vehicle body left side of the base portion 23. I can't. By disposing the motor 12 below the end of the base portion 23 on the right side of the vehicle body, the wire 12a connecting the exhaust control valve 11b and the motor 12 could be formed short. Incidentally, conventionally, the motor 12 is arranged near the lower part of the seat, and the wire connecting the motor and the exhaust control valve is long.

When the rear arm 10 is formed in a V-shape when viewed from the right side of the vehicle body as described above, the arm 22 on the right side of the vehicle body is formed by the lower arm 32 and the upper arm 34, which is lighter than the conventional one. Could be realized. This is because when the uppermost part of the arm 22 on the right side of the vehicle body and the uppermost part of the arm 21 on the left side of the vehicle body are connected to each other in order to improve the rigidity of the rear arm 10, the upper end portion of the upper arm 34 of the arm 22 on the right side of the vehicle body is Left arm 2
This is because it can be connected to 1.

That is, the arm 22 on the right side of the vehicle body is formed by a lower arm 32 and an upper arm 34,
Since members are present only on the lower side and the upper side of the arm 22 and a space S can be formed between the lower side and the upper side, it is lighter than a conventional rear arm in which a plate-shaped member extends in the vertical direction from the lower side to the upper side. Can be realized.

In addition, the rear arm 1 according to this embodiment
0 indicates that the lower arm 32 of the arm 22 on the right side of the vehicle body adjacent to the exhaust pipe is formed by providing an end bracket 32d which is a separate body from the rear end of the pipe portion 32c,
Since the rear end of the upper arm 34 is joined across the pipe portion 32c and the end bracket 32d,
The load is transmitted to the upper arm 34 from both the pipe portion 32c and the end bracket 32d. For this reason, it is possible to reduce the stress in the shearing direction generated in the welded portion of the pipe portion 32c and the end bracket 32d. Besides,
The angle formed by the lower arm 32 and the upper arm 34 is a relatively small acute angle as compared with a general rear arm that is not V-shaped when viewed from the side. Therefore, the lengths of the welded portions of these two are made relatively long. be able to. As a result, the strength of the welded portion can be improved.

Further, the rear arm 10 includes the upper arm 34 of the arm 22 on the right side of the vehicle body and the arms 2 on the left and right sides.
1 and 22 can be connected to each other, and the upper arm 3
3, 34 function as cross members. Therefore, the rigidity of the rear arm 10 can be improved.

Lower arm 32 of arm 22 on the right side of the vehicle body
Is formed by welding two panels, an inner half and an outer half 32b, which are formed on the inner side of the vehicle body and the outer side half portion 32b of the vehicle body. Therefore, for example, the rigidity is relatively high as compared with the case where the panel is formed by extrusion. It is possible to form the front portion which is required to have a large cross-sectional area, and the rear end portion, which may have relatively low rigidity, so that the cross-sectional area becomes small and the weight can be reduced. Therefore, the degree of freedom in designing the cross-sectional shape of the lower arm is increased. In the rear arm 10 according to this embodiment, the hydraulic hose 42 of the rear wheel brake 41 is passed through the space S formed between the lower arm 32 and the upper arm 34 of the arm 22 on the right side of the vehicle body. It functions as a protective cover that covers the hydraulic hose 42 from above. Therefore, the hydraulic hose 42 can be protected by using the rear arm 10.

In addition, according to this embodiment, the brake caliper 44 of the rear wheel brake 41 is connected to the axle 9 of the rear wheel 9.
Since the brake caliper 44 is disposed above b, the brake caliper 44 is disposed above the lower arm 32, and the brake caliper 44 is provided to the brake caliper 44 without greatly bending the hydraulic hose 42 piped between the lower arm 23 and the upper arm 34. Can be connected.

[0034]

As described above, according to the present invention, the arm adjacent to the exhaust pipe can form a space between the lower arm and the upper arm, and thus extends in the vertical direction as compared with the conventional case. The plate-shaped portion can be reduced. Therefore, it is possible to reduce the weight of the V-shaped rear arm when viewed from the side.

According to the second aspect of the invention, the load is transmitted from both the lower arm body and the end portion to the upper arm, and the stress in the shearing direction generated at the welded portion between the lower arm body and the end portion is reduced. Therefore, the rear arm having high rigidity can be formed.

According to the third aspect of the invention, the left and right arms can be connected to each other by the upper arm, and the upper arm functions as a cross member, so that a rear arm having high rigidity can be formed.

According to the invention described in claim 4, as compared with the case where the lower arm is formed by extrusion, the cross-sectional shape at an arbitrary part in the front-rear direction can be changed as compared with other parts, which is a design factor. You have more freedom. Therefore, it is possible to provide a rear arm that achieves both improved rigidity and reduced weight.

According to the fifth aspect of the invention, since the upper arm functions as a protective cover for covering the hydraulic hose of the rear wheel brake from above, the hydraulic hose is formed by using the rear arm formed in a V shape in side view. Can be protected.

A rear arm for a motorcycle according to a sixth aspect of the invention is the rear arm for a motorcycle according to the fifth aspect of the invention, in which the rear brake caliper is disposed above the rear axle. According to this invention, since the rear brake caliper is arranged above the lower arm, the hydraulic hose connected between the lower arm and the upper arm can be connected to the rear brake caliper without being greatly bent. Therefore, the piping of the hydraulic hose is simplified, and the workability of the piping work can be improved.

[Brief description of drawings]

FIG. 1 is a side view of a motorcycle using a rear arm according to the present invention.

FIG. 2 is a right side view of a main part.

FIG. 3 is a diagram showing a rear arm.

FIG. 4 is a sectional view taken along line IV-IV of the lower arm in FIG.

5 is a sectional view taken along line VV in FIG.

FIG. 6 is an enlarged side view showing an exhaust control valve portion of the exhaust device.

FIG. 7 is a rear view of a motor mounting portion.

FIG. 8 is a side view of the motor.

[Explanation of symbols]

9 ... rear wheel, 10 ... rear arm, 13 ... silencer, 1
4 ... Downstream exhaust pipe 21, 22 ... Arm, 23 ... Base part,
24 ... Pivot shaft, 32 ... Lower arm, 34 ... Upper arm, 41 ... Rear wheel brake, 42 ... Hydraulic hose, S ... Space.

Claims (6)

[Claims] 1. An exhaust pipe having left and right arms extending laterally on the side of a rear wheel and a pivot shaft connecting base for connecting front end portions of these arms to each other and an arm adjacent to the exhaust pipe. In a rear arm for a motorcycle formed in a V shape when viewed from the side where is located, an arm adjacent to the exhaust pipe, a lower arm that supports an axle of a rear wheel at a rear end portion,
A rear arm for a motorcycle, which is formed by an upper arm extending upward from the upper surface of the rear end of the lower arm. 2. The rear arm for a motorcycle according to claim 1, wherein the lower arm of the arm adjacent to the exhaust pipe is formed by providing a rear end portion of the lower arm body with an end portion that is separate from the rear arm portion. A rear arm for a motorcycle, in which a rear end of the upper arm is joined to the lower arm body and the end portion so as to be joined to each other. 3. The motorcycle rear arm according to claim 1, wherein the upper arm is connected to the top of the base at the front, and is curved rearwardly to be connected to the upper surface of the rear end of the other arm. Rear arm for. 4. The rear arm for a motorcycle according to claim 1, wherein the lower arm of the arm adjacent to the exhaust pipe is formed by welding two inner and outer panels. 5. The rear arm for a motorcycle according to claim 1, wherein a hydraulic hose for a brake for a rear wheel is passed through a space formed between a lower arm and an upper arm. 6. The rear arm for a motorcycle according to claim 5, wherein the rear brake caliper is arranged above the rear axle.