JPH08337189A - Rear wheel supporting device of motorcycle - Google Patents

Abstract

PURPOSE: To improve the torsional rigidity in the vicinity of an axle supporting member of each arm by bending a first arm downward, forming its rear part so as to be an upwardly inclined part, and allowing the reference line of the axle to pass the approximate center of a narrow angle part constituted by the first and second arms and an axle supporting member. CONSTITUTION: A second arm is inclined rearward and connected to an axle supporting member 8, a first arm is bent downward, its rear inclined part 6f is connected to the axle supporting member 8, and the reference line A connecting a pivot axis 5 to an axle 9 is allowed to pass the approximate center of a narrow angle part. The first arm 6 and the second arm 7 are connected to the axle supporting member 8 above and below the axle 9 to improve the torsional rigidity of the axle supporting member 8. The narrow angle part constituted by the first arm 6 and the second arm 7 can be increased in size without increasing the axle supporting member 8, and the torsional rigidity of the axle supporting member 8 can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear wheel support device for a motorcycle, and more particularly to an advantageous structure of a rear swing arm and an axle support member provided at a rear end portion thereof.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 59-143787 (hereinafter referred to as "first document") discloses a lower first swing support for a rear swing arm of a motorcycle which is swingably supported at a rear portion of a vehicle body frame.
It is composed of an arm and an upper second arm, and these first and second arms are arranged vertically with a horizontal line passing through the axle interposed therebetween, and the rear end of the first arm and the front end of the second arm are attached to the vehicle body frame. A rear wheel support device of a motorcycle having a structure in which a cushion unit is provided between positions is shown.

Further, in Japanese Patent Application Laid-Open No. 55-152680 (hereinafter referred to as the second document), a lower first arm extends rearward substantially horizontally and is connected to an upper second arm by an axle support member. A rear wheel support device for a motorcycle having a structure in which a cushion unit is provided between the front end of the second arm and the vehicle body frame is shown.

[0004]

By the way, in the rear wheel supporting device of the first document, since the cushion unit is arranged near the axle, the layout of the power transmission members and the like is restricted. Further, in the rear wheel support device of the second document, since the lower first arm extends substantially horizontally rearward, when the angle of contact between the axle support member and the first and second arms is increased, However, there is a problem that the axle support member becomes large. Then, this invention aims at solving such a problem.

[0005]

A rear wheel support device for a motorcycle according to the present invention pivotally supports a front end portion to a rear portion of a vehicle body frame by a pivot shaft, and an axle support member at a rear end portion. A first arm that supports the axle of the rear wheel via the first arm and a first arm that is disposed obliquely downward toward the rear above the first arm. The front end portion is connected to the front half portion of the first arm, and the rear end portion is What has a rear swing arm constituted by a second arm connected to an axle support member, wherein the first arm is bent downward so as to sandwich an axle reference line connecting the pivot shaft and the axle with the first arm and the second arm. The inclined portion formed on the rear portion of the first arm and the rear portion of the second arm form a flank portion at the connecting portion of the axle support member, and the axle reference line passes through substantially the center of the flank portion. Together with the body frame and the rear swing arm A cushion unit for binding than the second frame front, characterized in that attached to the front.

[0006]

As described above, the first arm is curved downward, and the rear portion is formed to be an upwardly inclined portion, and the approximate center of the flank portion formed by the first and second arms and the axle support member is pivoted. Since the axle reference line that connects the axle and the axle passes through, the torsional rigidity of the first and second arms near the axle support member is improved.

In addition, since the first arm is curved downward, the angle between the first and second arms and the axle support member can be increased, and the torsional rigidity can be increased without increasing the size of the axle support member. Can be improved.

Moreover, since the cushion unit is arranged in front of the front end of the second arm, the power transmission member can be easily attached and arranged.

[0009]

1 to 9 show one embodiment of the present invention. FIG. 1 shows a side surface shape of a motorcycle, FIG. 2 shows an enlarged side surface shape of a rear swing arm, and FIG. 3 shows a plane shape of a lower side of a rear swing arm. First,
The schematic structure will be described. As shown in FIG. 1, an engine 4 is supported by a vehicle body frame 3 having front ends attached to a steering shaft 2 of front wheels 1. A rear swing arm is swingably attached to the rear portion of the body frame 3 by a pivot shaft 5.

The rear swing arm is made of a pipe-shaped member and has a first arm 6 on the lower side and a second arm 7 on the upper side. Note that, as shown in FIG. 3, the rear swing arm is a double-sided type, and the first arm 6 is provided in a pair of left and right. For the sake of description, the right side of the vehicle body is hereinafter referred to as the right side first arm 6r. The second arm 7 is a substantially U-shaped member.

The rear part of each arm is converged on a pair of left and right axle support members 8 and connected by a fitting structure described later, and welded at a welded joint W. Both ends of the axle 9 are supported by the central portion of the axle support member 8, and
A rear wheel 10 is rotatably supported by the.

As shown in FIGS. 1 and 2, the first arm 6
As for the side surface shape of (6r), a front portion forms an inclined portion 6d extending downward from the pivot shaft 5 and a rear portion thereof forms an axle support member 8.
Forming an inclined portion 6f which extends upward toward the upper side, and an intermediate portion of these inclined portions 6d and 6f forms a horizontal portion 6e which extends rearward in a substantially horizontal direction, and has a shape curved downward from the axle 9 as a whole. I am doing it.

The second arm is straight and is inclined downward toward the rear. The inclined portion 6f of the first arm 6 is obliquely attached to the axle support member 8 toward the upper side.
The arm 7 is attached to the axle support member 8 obliquely downward.

For this reason, the first arm 6 (6r) and the second arm 7 are provided with a pivot shaft 5 and an axle shaft 9 at the front end of the first arm 6.
Are arranged in a state of being vertically divided with a reference line A connecting between them being arranged, and the rear part of each arm is connected to the axle support member 8 by forming a space S at a corner. This space S is
It is a space surrounded by the rear part of each arm and the axle support member 8 and protected, and is a space where it is easy to operate by putting a hand from the side of the vehicle body. The reference line A passes through the approximate center.

As for the first arm 6 (6r) and the second arm 7, a cushion bracket 11 welded to the front center of the second arm 7 is passed between the left and right first arms 6 and 6r. By connecting with the cross pipe 12, a rigid structure having a substantially triangular side view is formed (see FIG. 1).

The cushion bracket 11 is a member having a substantially U-shaped cross section, and the known rear cushion unit 1 is here.
3, one end 14 is attached, and the other end is attached to the body frame 3 side. Therefore, the cushion unit 13 is located in front of the front end of the second arm 7.

Next, the detailed structure of the rear swing arm will be described. As shown in FIG. 3, a front end portion 6a of the first arm 6 is squeezed inward to flatten the front portion of the rear swing arm, and a bearing holder 5a for supporting the pivot shaft 5 is welded to the front end portion thereof. Has been done. On the other hand, a similar bearing holder 5b is also welded to the front part of the right first arm 6r. The plane shape of the first arm 6 is set so as to follow the chain C that is the power transmission member of this embodiment.
On the other hand, the front part of the right first arm 6r is not restricted by the chain C, and therefore is bent toward the center of the vehicle body.

Further, one end of the bridge 6b is welded to the bearing holder 5a, and the other end extends rearward and is connected to one end of the cross pipe 6c by welding. The other end of the cross pipe 6c is welded to the right first arm 6r, whereby the cross pipe can be provided so as not to interfere with the chain C and the front part of the rear swing arm can be reinforced.

On the other hand, the axle support member 8 provided on the rear portion of the rear swing arm is a molded product obtained by forging or the like, and a raised portion is integrally formed on the front portion side thereof (see FIG. 5). Cylindrical protrusions 15 and 16 are formed on the tip side of the raised portion,
The first arm 6 (6r) and the second arm 7 can be fitted into the respective rear end openings. These protrusions 15 and 1
6, there are axial lightening holes 17 and 1 as shown in FIG.
8 is formed, and the spot facing parts 17a and 18a at the tip thereof are formed.
Respectively communicate with the lightening holes 19 formed on the back surface of the axle support member 8. However, the lightening holes 17 and 18 may be omitted.

Further, an axle 9 is provided at the center of the axle support member 8.
Slots 20 are formed for accommodating both ends of each of the two and adjusting the position in the front-rear direction. Reference numeral 21 is a scale indicating the adjustment position of the axle 9.

Further, as shown in FIGS. 4 and 7, a screw hole 22 is formed from the front end of the elongated hole 20 to the front edge of the axle supporting member 8, and an adjusting member 23 made of a bolt is screwed into the screw hole 22. There is. The adjustment member 23 is located on the front side of the axle support member 8 and protrudes from above and below into the space S of the angled portion surrounded by the first arm 6 and the second arm 7.
Is positioned by and its tip is engaged with the counterbore hole 26 of the collar 25 which is fitted around the axle 9 and accommodated in the slot 20.

As shown in FIG. 9, the collar 25 has a cylindrical shape, and two notches 27 are formed in parallel at symmetrical positions on the side surface. The interval between the cutouts 27, 27 matches the narrow width of the elongated hole 20. However, one end of the cutout portion 27 is stopped in the middle of the collar 25,
The remaining portion forms a flange portion 28, and abuts on a step portion 20a (see FIG. 4) formed around the elongated hole 20. The counterbore 26 has a cutout 27.
It is formed at two symmetrical positions on the side surface of the collar 25 between 27. Reference numeral 29 is a through hole for passing the axle support member 8.

A chain tensioning mechanism is composed of the adjusting member 23 and the collar 25. The adjusting member 23 of the chain tensioning mechanism is located on or near the reference line A (see FIG. 1).

Reference numeral 30 in FIGS. 1 to 3 is a break drum, 31 is a break lever, and 32 is a break rod 32. The brake rod 32 is made of a pipe member, and as shown in FIG. 3, one end 32a thereof is crushed inwardly to be flattened and attached to the brake drum 30 by a bolt 33. The other end 32b is crushed outward and flattened, and is connected to a stay 34 attached to the lower end of the right first arm 6r. As a result, the break rod 32 formed in a straight line can be used. Since it is necessary to attach the stay 34 to the three-dimensional bent portion of the first right arm 6r, a press plate 36 having an oblique plane 35 is welded to the back side of the first right arm 6r.

Reference numeral 37 is a driven sprocket,
It is driven by the drive sprocket 38 of the engine 4 via the chain C.

Next, a method of connecting the rear end portions of the arms 6 (6r) and 7 and the axle support member 8 will be described. First, the protrusions 15 and 16 are fitted into the rear end openings of the arms 6 (6r) and 7, respectively. At this time, each arm 6 (6r) and 7
The rear end is left cut substantially perpendicular to the axial direction and trimming is omitted. Further, since the protrusions 15 and 16 are molded products by forging or the like, the molding surface can be used as it is when fitting, and trimming is also omitted. Therefore, after joining the two by fitting, welding is performed along the rear ends of the arms 6 (6r) and 7. In this case, since the rear ends of the arms 6 (6r) and 7 are still cut and are not processed by drawing or the like, it is possible to minimize the welding length along the periphery of the rear ends. As a result, the rear ends of the arms 6 (6r) and 7 and the axle support member 8 are firmly joined at the welded joint W.

In the present embodiment, the lightening holes 17 and 18 are communicated with the lightening hole 19 of the axle support member 8 by the tips of the counterbore portions 17a and 18a. therefore,
In the painting process, the pretreatment liquid, paint, etc., which has entered the pipe portion of each arm, can be extracted from this communication portion and discharged to the outside through the lightening hole 19, and there is no need to separately provide a hole for this. It is convenient.

The present invention is not limited to the above embodiment,
Various modifications and applications are possible. For example, each arm 6
The fitting structure of the rear end portions of (6r) and 7 and the axle support member 8 can be reversed.

Next, the operation of this embodiment will be described. In the present embodiment, the second arm 7 is tilted rearward to be connected to the axle support member 8, the first arm 6 is curved downward, and the rear inclined portion 6f is connected to the axle support member 8, In addition, since the reference line A connecting the pivot shaft 5 and the axle 9 passes through substantially the center of the included angle portion, the first arm 6 and the second arm 7 are connected to the axle support member 8 at the vertical position of the axle 9. As a result, the torsional rigidity of the axle support member 8 can be improved.

In addition, the angled portion formed by the first arm 6 and the second arm 7 can be increased without increasing the size of the axle support member 8 and the torsional rigidity of the axle support member 8 can be improved. it can.

In addition, the cushion unit 13 has a second
Since the arm C is arranged in front of the front end of the arm 7, the chain C, which is a power transmission member, can be easily attached and arranged.

[Brief description of drawings]

FIG. 1 Side view of the vehicle body

[Figure 2] Side view

FIG. 3 is a plan view of the first arm.

FIG. 4 is a side view of the main part.

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

6 is a sectional view taken along line VI-VI of FIG.

FIG. 7 is an X view of FIG.

8 is a sectional view taken along line VIII-VIII of FIG.

FIG. 9 is a perspective view of a main part.

[Explanation of symbols]

3 ... Body frame, 5 ... Pivot shaft, 6 ... First arm,
6r ... Right side first arm, 7 ... Second arm, 8 ... Axle support member, 9 ... Axle, 10 ... Rear wheel, 15, 16 ... Protrusion, W ...
Welded joint

Claims (1)

[Claims] 1. A first arm which pivotally supports a front end portion to a rear portion of a vehicle body frame by a pivot shaft, and supports a rear wheel axle via a axle support member at the rear end portion; and a first arm of the first arm. It has a rear swing arm which is disposed so as to be slanted downward and upward and has a front end connected to the front half of the first arm and a rear end connected to a second arm connected to the axle support member. In the above, the first arm is bent downward so as to sandwich the axle reference line connecting the pivot shaft and the axle between the first arm and the second arm, and the upwardly inclined portion formed on the rear portion of the first arm and the rear portion of the second arm. Forms a chamfered portion at the connecting portion of the axle support member, and the axle reference line passes through substantially the center of the chamfered portion, and a cushion unit that connects the vehicle body frame and the rear swing arm is provided from the front end of the second frame. Forward too That with a wheel support device after the motorcycle, characterized in.