JP2612705B2 - Rear wheel support device for motorcycles - Google Patents

Description

Description: 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 configuration of a rear swing arm and an axle support member provided at a rear end thereof. Regarding the coupling structure.

[Prior Art] A first arm pivotally supported on a rear swing arm of a motorcycle by a pivot shaft at a rear portion of a vehicle body frame,
A second arm is disposed obliquely above the second arm, and the rear ends of both arms are connected to an axle support member that supports the axle of the rear wheel.
-55080). In general, both arms are pipe members, and the axle support member is a press-formed plate-shaped member. In such a case, the end of each arm is previously squeezed or crushed with a slit, and a blank portion is formed on the axle support member side, and after fitting both, the periphery thereof is welded. Was.

Japanese Utility Model Laid-Open Publication No. 51-45759 discloses that the above-mentioned plate-like member is used as a mating member, and a groove having a semicircular cross-section is press-formed in each of them, and a cylindrical portion is formed in the mating portion by joining both plate-like members. In the figure, a circular hole is provided, and the rear end of the pipe member is inserted into the circular hole and welded.

[Problems of the Prior Art] By the way, the above-described conventional connection structure requires many processing steps. That is, on the arm side, it is necessary to cut, form (form a slit), squeeze or crush and trim the pipe member.

On the other hand, blanking, trimming and drilling are required on the axle support member side. Further, when the two parts are joined and the periphery is welded, it is necessary to perform a welding operation along the periphery of the drawn or crushed portion, so that the welded portion must be relatively long.

Therefore, an object of the present invention is to significantly reduce the number of processing steps of such a connecting portion, and to reduce the weight and manufacture of the axle connecting member.

[Means for Solving the Problems] A rear wheel support device for a motorcycle according to the present invention pivotally supports a front end portion with a rear pivot shaft of a vehicle body frame, and attaches an axle support member to a rear end portion. A rear swing arm constituted by an arm that supports an axle of a rear wheel via a fork or a cast, wherein the axle support member is formed by forging or casting, and a rear end of the arm is provided on a front side of the axle support member. A pipe-shaped protrusion that can be fitted to the portion is integrally provided, and a hollow portion that opens toward the inside of the vehicle body is formed between the protrusion of the axle support member and the axle support portion. And the rear end of the arm is fitted.

[Operation of the Invention] In the joint structure of the arm and the axle support member according to the present invention, first, only the arm side needs to be cut, and trimming is unnecessary in the usual case. The axle support member is formed in several steps by forming means such as forging. At this time, the protruding portion and the bulging portion that bulges outward continuously from the protruding portion are integrally formed. Therefore, the rigidity of the arm and the axle support member can be easily balanced, and stress is less likely to be concentrated at the joint between the axle support member and the arm. Furthermore, since the lightening portion is formed on the inner surface of the bulging portion of the axle support portion, the weight of the axle support member can be reduced without impairing the appearance.
Furthermore, in the connecting step, the end of the rear swing arm and the projection are fitted together, and the periphery of the fitted portion is welded. Since this welding operation is performed along the cut surface of the arm, the length of the weld is minimized.

In addition, when the axle support member is formed by a left-right split mold, the mold on the side forming the surface facing the inward side of the vehicle body can be provided with a molded portion of the lightening portion, so that the mold structure can be simplified. it can.

Further, since the hollow portion and the lightening portion communicate with each other through the communication port, the pretreatment liquid or paint or the like that has entered the pipe of the arm can be discharged to the outside from the lightening portion. Since there is no need to provide a separate drain hole, workability is improved.

Further, since the communication port is located within the thickness of the axle support member, it is difficult to see from outside the vehicle body, and the appearance is improved.

[Embodiment] Figs. 1 to 9 show an embodiment of the present invention. FIG. 1 shows a side view of the motorcycle, FIG. 2 shows an enlarged side view of the rear swing arm, and FIG. 3 shows a plan view of the lower part of the rear swing arm. First, the schematic structure will be described. As shown in FIG. 1, an engine 4 is supported on a vehicle body frame 3 having a front end attached to a steering shaft 2 of a front wheel 1. A rear swing arm is pivotally mounted on 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. As shown in FIG. 3, the rear swing arm is a double-supported type, and the first arm 6 is provided as a pair of left and right arms. Hereinafter, for the sake of explanation, in particular, the right side of the vehicle body will be referred to as the right first arm.
6r. The second arm 7 is a substantially U-shaped member.

The rear portion of each arm converges on a pair of left and right axle support members 8 and is connected by a fitting structure described later, and is welded at a welding connection portion W. Both ends of the axle 9
The axle 9 is supported at the center of the axle support member 8 and the rear wheel 10
Are rotatably supported.

As shown in FIGS. 1 and 2, the first arm 6 (6r)
Is curved downward, and the second arm 7 is inclined upward and forward. Therefore, the first arm 6 (6
r) and the second arm 7 are arranged vertically above and below a reference line A connecting the pivot shaft 5 and the axle 9 at the front end of the first arm 6, and the rear portion of each arm is axle support. 8
A space S at the angle is formed to be connected. This space S is a space which is protected by being surrounded by the rear portion of each arm and the axle support member 8, and is a space which can be easily operated by putting a hand from the side of the vehicle body. In addition, the first arm 6 (6
r) and the second arm 7 are connected to each other by connecting a cushion bracket 11 welded to the front center of the second arm 7 with a cross pipe 12 passed between the left and right first arms 6 and 6r. It has a rigid structure having a substantially triangular appearance (see FIG. 1).

The cushion bracket 11 is a member having a substantially letter-shaped cross section. One end 14 of a known rear cushion unit 13 is attached to the cushion bracket 11, and the other end is attached to the vehicle body frame 3 side.

Next, the detailed structure of the rear swing arm will be described. As shown in FIG. 3, the front end of the rear swing arm is flattened by the front end 6a of the first arm 6 being narrowed inward, and a bearing holder 5a for supporting the pivot shaft 5 is provided at the front end. Welded. On the other hand, the right first arm
A similar bearing holder 5b is welded to the front of 6r. Note that the planar shape of the first arm 6 is substantially linear so as to be along the chain C, while the right first arm 6r
The front part is bent toward the center of the vehicle body because it is not restricted by the chain C.

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
It is welded to the right first arm 6r, so that a 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 including the axle support portion 8a provided at the rear portion of the rear swing arm and the projections 15 and 16 is a molded product by forging or the like, and has a bulging portion on the front side of the axle support member 8a.
19a are integrally formed (see FIG. 5). At the tip end of the bulging portion 19a, substantially bottomed cylindrical protrusions 15 and 16 are formed.
The arm 6 (6r) and the second arm 7 can be fitted into respective rear end openings. The projections 15 and 16 are formed with axial hollow portions 17 and 18 as shown in FIG.
The counterbore portions 17a and 18a at the ends communicate with the inside of a lightening hole 19 formed on the back surface of the bulging portion 8a of the axle support member 8 through a communication port (see FIG. 8). In FIG. 8, a lightening hole 19 is formed by an elongated hole 20 serving as an axle support portion and projections 15 and 16.
It is open toward the inside of the car body between them. The bulging portion 19a can maintain the rigidity balance at the connecting portion between the axle support member 8 and the first and second arms 6, 7, avoiding concentration of stress, and supporting the vehicle by the lightening hole 19. The weight of the member 8 is also reduced.

In the center of the axle support member 8, a slot 20 for accommodating both ends of the axle 9 and adjusting its front-rear position.
Are formed as axle supports. 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 support member 8, and an adjusting member 23 made of a bolt is screwed into the screw hole 22. . The adjusting member 23 is located on the front side of the axle support member 8,
It protrudes into the space S of the angled portion surrounded by the arm 6 and the second arm 7, is positioned by the lock nut 24, and its tip is fitted around the axle 9 to form the elongated hole 20.
It engages a counterbore 26 in a collar 25 housed therein.

As shown in FIG. 9, the collar 25 has a cylindrical shape, and two notches 27 are formed in parallel at the target positions on the side surfaces. The space between the notches 27 corresponds to the narrow width of the elongated hole 20. However, one end of the notch 27 is
Stopped in the middle of the collar 25, the remaining part is a flange
28, and comes into contact with a step 20a (see FIG. 4) formed around the elongated hole 20. The counterbore hole 26 is formed at two symmetrical positions on the side surface of the collar 25 between the notches 27. Reference numeral 29 is a through hole for passing the axle support member 8.

A chain tensioning mechanism is constituted by the adjusting members 23 to the collar 25. Also, the adjusting member of the chain tension mechanism
Reference numeral 23 is located on or near the reference line A (see FIG. 1).

1 to 3, reference numeral 30 denotes a brake drum, 31 denotes a brake lever, and 32 denotes a brake rod 32. The brake rod 32 is made of a pipe member.
As shown in the figure, one end 32a is crushed inward and flattened, and is attached to the brake drum 30 by a bolt 33. The other end 32b is squashed outward and flattened, and is connected to a stay 34 attached to the lower end of the right first arm 6r. Thereby, the brake rod 32 formed linearly can be used. The press plate 36 having the oblique plane 35 is welded to the back side of the right first arm 6r because the stay 34 needs to be attached to the three-dimensional bent portion of the right first arm 6r.

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

Next, a method of connecting the rear ends of the arms 6 (6r) and 7 to the axle support member 8 will be described. First, each arm 6 (6
r) Fit the projections 15 and 16 into the rear end openings of 7 and 7.
At this time, the rear ends of the arms 6 (6r) and 7 remain cut at substantially right angles to the axial direction, and trimming is omitted. Further, since the protrusions 15 and 16 are formed products by forging or the like, the formed surfaces can be used as they are when they are fitted, and the trimming is also omitted. Then, after joining the two by fitting, welding is performed along each rear end of each arm 6 (6r) and 7. In this case, the rear ends of the arms 6 (6r) and 7 are still cut and are not processed such as drawing, so that the minimum welding length can be set 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 engaged at the weld joint W.

In the present embodiment, the hollow portions 17 and 18 communicate with the lightening holes 19 on the back surface of the bulging portion 19a of the axle support member 8 through the communicating holes at the tips of the counterbore portions 17a and 18a. therefore,
In the coating process, the pretreatment liquid, paint, and the like that have entered the pipe portion of each arm can be discharged to the outside from the lightening hole 19, and there is no need to separately provide a liquid discharging hole, which is convenient. Further, since the communication port is located within the thickness of the axle support member 8, it is difficult to see from outside the vehicle body, and the appearance is improved.

In addition, when the axle support member 8 is formed by a left-right split mold, a mold forming portion of a lightening portion can be provided in a mold forming a surface facing the inward side of the vehicle body. Can be.

In addition, even when a space that cannot be formed by dividing the projection 16 (15) into left and right portions is formed, as in the case of the hollow portion 18, the entire bulging portion 19a including the hollow portion 18 and the lightening hole 19 in FIG. As compared with the case of forming a pipe, the hollow portion 18 can be made smaller, so that molding can be facilitated.

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

[Effects of the Invention] In the joint structure of the arm and the axle support member according to the present invention, the processing on the arm side only requires cutting, drawing and the like are unnecessary, and trimming can be omitted. Also, the axle support member is molded in several steps by molding means such as forging,
No machining such as blanking, trimming and drilling is required. Therefore, the man-hour is significantly reduced. Further, the welding operation in the joining step can be performed so as to minimize the length of the welded portion, thereby facilitating the operation. Therefore, the number of processing steps related to the connection between the arm and the axle support member can be significantly reduced, and the work can be easily performed.

Furthermore, the axle support member is formed integrally with the protrusion and the bulge bulging outward continuously from the protrusion by molding means such as forging, so that the rigidity of the arm and the axle support member is balanced. Thus, concentration of stress at the joint between the axle support member and the arm can be avoided.

Further, since the lightening portion is formed on the inner surface of the bulging portion of the axle supporting portion, the weight of the vehicle supporting member can be reduced without deteriorating the appearance.

In addition, when the axle support member is formed by a left-right split mold, a mold forming part of the lightening portion can be provided on the mold that forms the surface facing the inward side of the vehicle body. The mold structure can be simplified as compared with the case of molding into a shape.

Further, since the hollow portion of the projection and the lightening portion communicate with each other through the communication port, the pretreatment liquid, paint, and the like that have entered the pipe portion of the arm can be discharged from the lightening portion to the outside. It is not necessary to provide a special drain hole for
Workability can be improved.

Further, since the communication port is located within the thickness of the axle support member, it is difficult to see from outside the vehicle body, and the appearance can be improved.

[Brief description of the drawings]

1 to 9 show an embodiment, FIG. 1 is a side view of a vehicle body, FIG. 2 is a side view thereof, FIG. 3 is a plan view of a first arm, and FIG. FIG. 5, FIG. 5 is a cross-sectional view taken along the line VV of FIG. 4, FIG. 6 is a cross-sectional view taken along the line VI-VI of FIG. 4, FIG. VIII-VIII sectional view of the figure,
FIG. 9 is a perspective view of a main part. (Explanation of reference numerals) 3 ... body frame, 5 ... pivot shaft, 6 ... first arm, 6r ... right first arm, 7 ... second arm, 8 ...
... Axle support member, 9 ... Axle, 10 ... Rear wheel, 15, 16 ...
Projection, W: welded joint.

Claims (1)

(57) [Claims] 1. An automatic vehicle having a rear swing arm comprising a front end portion pivotally supported by a rear pivot shaft of a vehicle body frame and an arm supporting a rear wheel axle via an axle support member at a rear end portion. In the rear wheel support device for a motorcycle, the axle support member protrudes substantially forward from a front portion to a substantially bottomed cylindrical shape from a front portion and can be fitted to a rear end portion of the arm. Part, and the whole is integrally formed by forging or casting, and a bulge extending continuously in the axial extension direction and bulging outward continuously with the protrusion is integrated with the outer surface of the axle support part. The hollow portion formed on the inner surface of the axle support portion where the bulging portion is formed is opened toward the vehicle body, and the hollow portion formed in the hollow portion and the protrusion is formed. Through a communication port formed within the thickness of the axle support member. A rear wheel support device for a motorcycle, comprising: