JP2698850B2 - 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 a rear swing arm and an axle support member provided at a rear end thereof. Related to the advantageous structure. 2. Description of the Related Art Japanese Unexamined Patent Publication No. Sho 59-143787 (hereinafter referred to as "first document") discloses a lower swing arm of a motorcycle that is pivotally supported by a rear portion of a vehicle body frame. First
An arm and an upper second arm, and the first and second arms are arranged vertically above and below a horizontal line passing through the axle, and a vehicle body frame is attached to a rear end of the first arm and a front end of the second arm. A rear wheel support device for a motorcycle having a structure in which a cushion unit is provided between positions is shown. In Japanese Patent Application Laid-Open No. 55-152680 (hereinafter referred to as "second document"), a lower first arm extends substantially horizontally rearward, and is connected to an upper second arm by an axle support member. A rear wheel support device of a motorcycle having a structure in which a cushion unit is provided between a front end of a second arm and a vehicle body frame is shown. [0004] In the rear wheel support device of the first document, since the cushion unit is arranged near the axle, the layout of the power transmission member 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, if the angle between the axle support member and the connecting portion between the first and second arms is made large. However, there is a problem that the axle support member becomes large. Therefore, an object of the present invention is to solve such a problem. 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 has an axle at a rear end portion. A first arm that supports an axle of a rear wheel via a support member, and is disposed above the first arm so as to diagonally descend rearward, and a front end is connected to a front half of the first arm. A rear swing arm having an end portion formed by a second arm connected to an axle support member, wherein the first arm is lowered so as to sandwich an axle reference line connecting the pivot axis and the axle between the first arm and the second arm. A bent portion is formed at the connecting portion of the axle support member by the upwardly inclined portion formed at the rear portion of the first arm and the rear portion of the second arm, and substantially the center of the bent portion is defined by the axle reference line. Passes, and the body frame and rear switch A cushion unit for connecting the swing arm to the front end of the second frame. According to the present invention, the first arm is bent downward, and the rear portion is formed so as to be inclined upward, and the angled portion formed by the first and second arms and the axle support member is substantially formed. Since the axle reference line connecting the pivot axis and the axle passes through the center, the torsional rigidity of the first and second arms near the axle support member is improved. Moreover, since the first arm is bent downward, the angle between the first and second arms and the axle support member can be increased, and the torsional rigidity can be achieved without increasing the size of the axle support member. Can be improved. In addition, since the cushion unit is disposed forward of the front end of the second arm, the attachment and arrangement of the power transmission member can be easily performed. FIG. 1 to FIG. 9 show an embodiment of the present invention. 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 a lower portion 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, the right side of the vehicle body is particularly referred to as a 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 joint W. Both ends of the axle 9 are supported at the center of the axle support member 8,
, A rear wheel 10 is rotatably supported. As shown in FIGS. 1 and 2, the first arm 6
The side shape of (6r) forms an inclined portion 6d whose front portion is inclined downward from the pivot shaft 5 and extends rearward, and its rear portion is an axle support member 8.
An inclined portion 6f extending upward and inclining toward the rear is formed, and an intermediate portion between the inclined portions 6d and 6f forms a horizontal portion 6e extending substantially horizontally rearward, and has a shape curved downward from the axle 9 as a whole. No. The second arm is straight, and is inclined downward toward the rear. The inclined portion 6f of the first arm 6 is attached to the axle support member 8 obliquely upward, and
The arm 7 is attached to the axle support member 8 obliquely downward. Therefore, the first arm 6 (6r) and the second arm 7 are connected to the pivot shaft 5 and the axle 9 at the front end of the first arm 6.
The arms are arranged in a vertically divided state with a reference line A connecting them therebetween, and the rear portion of each arm is connected to the axle support member 8 by forming a space S at an angle portion. This space S is
It is a space that is protected by being surrounded by the rear portion of each arm and the axle support member 8, and is easy to operate by inserting a hand from the side of the vehicle body. Note that the reference line A passes through substantially the center. The first arm 6 (6r) and the second arm 7 pass the cushion bracket 11 welded to the front center of the second arm 7 between the left and right first arms 6 and 6r. By connecting to the cross pipe 12, a rigid structure having a substantially triangular shape in a side view is formed (see FIG. 1). The cushion bracket 11 is a member having a substantially U-shaped cross section.
3 has one end 14 attached, and the other end attached to the vehicle body frame 3 side. For this reason, the cushion unit 13 is located ahead 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 6a of the first arm 6 is narrowed inward and flattened at a front portion of the rear swing arm, and a bearing holder 5a for supporting the pivot shaft 5 is welded to the front end. Have been. On the other hand, a similar bearing holder 5b is also welded to the front of the right first arm 6r. Note that the planar shape of the first arm 6 is set along the chain C which is the power transmission member of the present embodiment.
On the other hand, the front portion of the right first arm 6r 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 is welded to the right first arm 6r, so that 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 at the rear portion of the rear swing arm is a molded product formed by forging or the like, and a protruding portion is integrally formed on the front side (see FIG. 5). Cylindrical projections 15 and 16 are formed on the tip side of the ridge,
The first arm 6 (6r) and the second arm 7 can be fitted into respective rear end openings. These projections 15 and 1
6 are provided with holes 17 and 1 in the axial direction as shown in FIG.
8 are formed, and counterbore portions 17a and 18a at the tip thereof are formed.
Communicate with the lightening holes 19 formed on the rear surface of the axle support member 8, respectively. However, the lightening holes 17 and 18 may be omitted. An axle 9 is provided at the center of the axle support member 8.
A long hole 20 is formed for accommodating both end portions of the base member 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 support member 8, and an adjusting member 23 composed of a bolt is screwed into the screw hole 22. I have. The adjusting member 23 projects forward and downward into the space S of the angled portion surrounded by the first arm 6 and the second arm 7 on the front side of the axle support member 8.
, And its tip engages a counterbore 26 in a collar 25 which is fitted around the axle 9 and housed in the slot 20. As shown in FIG. 9, the collar 25 has a cylindrical shape, and two notch portions 27 are formed in parallel at symmetrical positions on the side surface. The interval between the notches 27 corresponds to the narrow width of the elongated hole 20. However, one end of the cutout portion 27 stops in the middle of the collar 25,
The remaining portion forms a flange portion 28 and comes into contact with a step portion 20a (see FIG. 4) formed around the elongated hole 20. The counterbore 26 has a notch 27.
Two positions are formed at symmetrical positions on the side surface of the collar 25 between the positions 27. Reference numeral 29 denotes a through hole through which the axle support member 8 passes. A chain tensioning mechanism is constituted by the adjusting members 23 to the collar 25. The adjusting member 23 of the chain tension mechanism is located on or near the reference line A (see FIG. 1). 1 to 3, reference numeral 30 denotes a brake drum, reference numeral 31 denotes a brake lever, and reference numeral 32 denotes a brake rod 32. The brake rod 32 is made of a pipe member. As shown in FIG. 3, one end 32a of the brake rod 32 is crushed inward and flattened, and is attached to the brake drum 30 by bolts 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 rear side of the right first arm 6r because the stay 34 needs to be attached to the three-dimensional bent portion of the first right arm 6r. Reference numeral 37 denotes a driven sprocket.
It 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, the projections 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 remains 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 fitting, and the trimming is also omitted. Therefore, 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 connected at the welding connection W. In the present embodiment, the lightening holes 17 and 18 and the lightening hole 19 of the axle support member 8 communicate with each other by the front ends 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 extracted from the communicating 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 between the rear end portions (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 inclined rearward to be connected to the axle support member 8, and the first arm 6 is bent 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 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. Therefore, the torsional rigidity of the axle support member 8 can be improved. Further, the angle 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. Further, the cushion unit 13 is connected to the second
Since the arm 7 is disposed forward of the front end, the chain C, which is a power transmission member, can be easily attached and arranged.

BRIEF DESCRIPTION OF THE DRAWINGS 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. FIG. 4 is a side view of a main part. FIG. FIG. 6 is a sectional view taken along line VI-VI in FIG. 4 FIG. 7 is a sectional view taken along line X in FIG. 4 FIG. 8 is a sectional view taken along line VIII-VIII in FIG. 4 FIG. DESCRIPTION OF SYMBOLS 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 protrusion, W ...
Weld joint

Claims (1)

(57) [Claims] A first arm for pivotally supporting the front end to a rear part of the vehicle body frame with a pivot shaft, and supporting a rear wheel axle at the rear end via an axle support member; and a rearward direction above the first arm. A rear swing arm which is disposed so as to be inclined downward and has a front end connected to the front half of the first arm and a rear end connected to the axle support member. The first arm is bent downward so as to sandwich an axle reference line connecting the pivot axis and the axle between the arm and the second arm, and an axle support member is formed by an upwardly inclined portion formed at a rear portion of the first arm and a rear portion of the second arm. An abutment portion is formed at the connecting portion of the vehicle, and the axle reference line passes through substantially the center of the abutment portion, and a cushion unit for connecting the body frame and the rear swing arm is mounted forward of the front end of the second frame. thing Wheel supporting apparatus after the motorcycle characterized.