JP3947277B2 - Vehicle suspension system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle suspension device suitable for a rear wheel suspension device of a motorcycle, and more particularly to a novel structure of a swing arm.
[0002]
[Prior art]
Japanese Patent Application Laid-Open No. 3-106528 shows a swing arm of a rear wheel suspension device for a motorcycle in which a pair of left and right main arms are connected by a cross member. Each main arm is formed so as to be tapered in the longitudinal direction by swaging the pipe member and then pressing the pipe member.
[0003]
Also known is a swing arm having a reinforcing structure in which a reinforcing member is provided above a straight main arm that is not tapered so that the reinforcing member has a substantially triangular shape in a side view.
[0004]
[Problems to be solved by the invention]
For a swing arm of a special vehicle such as a high-performance vehicle, in order to pursue high running performance, high rigidity, a high torsion center position (hereinafter referred to as a high torsion center) and weight reduction may be required at the same time. Here, the torsion center is the center of the torsion of the swing arm that occurs with the axle when the vehicle body is tilted in the left-right direction, and is indicated by the height from the ground contact point of the wheel.
[0005]
On the other hand, in the vehicle body structure of the above known example, the entire swing arm can be reduced in weight by making the main arm tapered, but the conditions of high rigidity and high twist center cannot be realized. That is, in the main arm that linearly connects the vehicle body connecting portion at the front end and the axle support portion at the rear end, the torsion center is approximately the height of the axle. Moreover, in order to obtain higher rigidity, a reinforcing structure different from the main arm is required.
[0006]
Therefore, as in the other known examples, if a reinforcing member having a substantially triangular structure in a side view is used on the main arm, the rigidity becomes high and the torsional center position is increased by the reinforcing member arranged above. Therefore, except for weight reduction, the two conditions of high rigidity and high twist center can be realized to some extent. However, since the rigidity of the reinforcing member is limited, even in such a structure, the torsion center cannot be so high, and there is a certain limit by itself.
[0007]
Accordingly, none of these known examples can simultaneously and sufficiently realize the three conditions required for the high-performance vehicle. Therefore, the present invention aims to realize a swing arm that simultaneously and sufficiently provides the three conditions of high rigidity, high twist center and light weight.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, a vehicle suspension apparatus according to the present invention includes a pair of left and right main arms having one end pivotally supported on the vehicle body side and supporting a wheel on the other end, and a swing member connecting the left and right main arms. In a vehicle suspension system including an arm and a shock absorber coupled to the cross member, a reinforcing member is disposed above the main arm and coupled to the cross member and the axle support portion of the main arm. A substantially triangular portion is formed between the main arm and the main arm, and the main arm is formed in a tapered shape whose width gradually decreases from the connecting portion of the cross member toward the wheel support portion, and the reinforcing member is connected. While the vicinity of the wheel support portion is a minimum cross-sectional area portion, and the vicinity of the rear end portion of the reinforcing member is a bent portion that bends downward at a steep angle ,
Said vehicle wheel support unit is an end-piece is a member for supporting the axle of the rear wheel to be welded to the rear end of the main arm, with a welded rear end of the reinforcing member to substantially the entire length of the end piece It is characterized by.
[0009]
【The invention's effect】
Since the main arm is tapered so that the vertical width gradually decreases from the cross member connecting portion toward the axle support portion, the overall weight can be reduced while sufficiently securing the rigidity of the cross member connecting portion to which the greatest force is applied. . Moreover, high rigidity is implement | achieved by making it a substantially triangular-shaped structure by the side view using a reinforcement member. In addition, by providing a reinforcing member above the main arm, the center of torsion can be raised upward, and the reinforcing member is connected to the axle support portion having the smallest cross-sectional area, and the vicinity of the rear end portion of the reinforcing member is suddenly lowered downward. A bent part that bends at an angle and an end piece that is welded to the rear end of the main arm are used as the wheel support part , and the rear end part of the reinforcing member is welded to substantially the entire length of the end piece so that the twist center is further raised. Therefore, a high torsion center that cannot be achieved with a straight main arm can be realized. Therefore, it is possible to simultaneously realize a light weight, a high rigidity and a high twist center required for a high-performance vehicle at a high level.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
1 is a side view of a swing arm according to an embodiment, FIG. 2 is a side view of the entire motorcycle to which the swing arm is applied, FIG. 3 is a side view of a rear wheel suspension device, and FIG. 4 is a perspective view of the swing arm. FIG. 5 is a plan view thereof, FIG. 6 is a side view of the main arm, FIG. 7 is a cross-sectional view taken along the line 7-7 in FIG. 6, and FIG. FIG. 9 is a cross-sectional view taken along line 9-9 in FIG.
[0011]
First, in FIG. 2, the motorcycle includes an engine 3 disposed between the front wheel 1 and the rear wheel 2, a main frame 4 extending in the front-rear direction in a pair of left and right above the engine 3 to support the engine 3, and thereafter A pair of left and right pivot frames 5 extending in the vertical direction from the end, a pair of left and right front forks 7 rotatably connected to a head pipe 6 provided at the front end of the main frame 4, a handle 8 for rotating the front forks 7, A front cowl 9 that covers the front of the vehicle body, a swing arm 10 whose front end is swingably supported by the pivot frame 5, a shock absorber 11 that connects the middle part of the swing arm 10 and the pivot frame 5, and a rear end of the swing arm 10 An axle 12 supported by the parts, a driven sprocket 13, a chain 14, and a drive sprocket 15 that transmits the output of the engine 3 are provided. Reference numeral 16 is a fuel tank, 17 is a seat rail, 18 is a rear cowl, and 19 is a seat.
[0012]
As shown in FIG. 3, the rear wheel suspension device transmits a force F input from the ground contact point with respect to the ground G of the rear wheel 2 from the axle 12 to the swing arm 10, and is provided at a lower position in the middle of the swing arm 10. The link connecting stay 20 transmits the shock to the shock absorber 11 via the link 21 so as to be buffered.
[0013]
The shock absorber 11 is a known one provided with progressive characteristics. The swing arm 10 swings up and down around the pivot 22 at the front end, and the link 21 is connected to the lower part of the pivot frame 5 via the link rod 23. Has been. Reference numerals 24 and 25 are mudguards and are detachably attached to the swing arm 10.
[0014]
As shown in FIGS. 1, 4 and 5, the swing arm 10 includes a pair of left and right main arms 30 and a pivot pipe 31 that connects these front ends, a cross member 32 that connects an intermediate portion, and an upper portion from the cross member 32. A reinforcing member 35 is provided between the upper end of the stay 33 extending to the rear end and the end piece 34 welded to the rear end of the main arm 30.
[0015]
The reinforcing member 35 is a member that has a substantially U shape in plan view, and that extends obliquely downward to the rear in a side view and forms a substantially triangular shape with the main arm 30. It is welded to the end piece 34 by forming a bent portion 36 that bends at a sharp angle. Reference numerals 37 and 38 are attachment stays for the mudguards 24 and 25.
[0016]
As shown in FIGS. 6 to 8, the left and right main arms 30 are each formed by being extruded into a hollow rectangular pipe having a vertically long cross section using an appropriate metal such as an aluminum alloy, and then the maximum portion 40 in the vicinity of the link connecting stay 20. The taper portion 42 has a taper shape that changes in cross section in a tapered shape so that the rear side is swaged and the vertical width gradually decreases toward the rear end portion 41. Therefore, the rear end portion 41 has the smallest cross-sectional area behind the maximum portion 40.
[0017]
Further, the front side of the maximum part 40 is also formed in a taper shape whose vertical width becomes narrower toward the front, and as is apparent from FIG. 6, the taper part 43 is provided with a slit 44 on the side surface from the front end side. The slit 44 is formed by press forming and welding.
[0018]
As shown in FIG. 8, the Damper rate (W2 / W1), which is the ratio of the width W1 of the maximum portion 40 to the width W2 of the rear end portion 41, is the required performance of the vehicle body, the structure of the swing arm 10 and the materials used. However, it is generally preferably about 60 to 80%, and in the present embodiment, it is about 67%.
[0019]
The cross member 32 is formed into a hollow shape by casting or the like using an appropriate material such as an aluminum alloy, and has a substantially I shape in plan view and is welded to the inside of the vicinity of the maximum portion 40 of the left and right main arms 30. Thus, the vicinity of the maximum portion 40 that receives the greatest force is reinforced. The link connection stay 20 projects in advance downward from the bottom of the cross member 32 and is integrally formed.
[0020]
Like the main arm 30, the reinforcing member 35 is formed by extruding and forming a hollow square pipe using an appropriate metal such as an aluminum alloy and then performing a three-dimensional bending process.
Similarly, the stay 33 is subjected to a three-dimensional bending process after extrusion processing to form a hollow shape, so that the front side as shown in FIG. 9 has a substantially U-shaped cross section.
[0021]
Next, the operation of this embodiment will be described. As shown in FIG. 1, the stay 33 and the reinforcing member 35 are provided above the main arm 30 to form a substantially triangular portion in a side view, so that the swing arm 10 can be made sufficiently high in rigidity. In addition, the weight can be reduced by using a tapered shape.
[0022]
In addition, by providing the reinforcing member 35 above the main arm 30, and by connecting the connecting portion with the reinforcing member 35 in the vicinity of the rear end portion 41 of the main arm 30 having the smallest cross-sectional area, the twist center C1 is A conventional twist center C0 using a combination of such a reinforcing member and a straight main arm also moves upward by a dimension D. For this reason, it becomes a high twist center structure. Therefore, light weight, high rigidity, and high twist center can be achieved simultaneously and at a high level.
[0023]
In addition, this invention is not limited to the said Example, It can deform | transform variously, For example, as a suspension apparatus, it can apply also for front wheels and can apply to the automatic three-wheeled vehicle etc. of an object vehicle.
[Brief description of the drawings]
1 is a side view of a swing arm. FIG. 2 is an overall side view of a motorcycle to which a swing arm is applied. FIG. 3 is a side view of a rear wheel suspension device. FIG. 4 is a perspective view of a swing arm. Fig. 6 is a plan view of the swing arm. Fig. 6 is a side view of the main arm. Fig. 7 is a sectional view taken along line 7-7 in Fig. 6. Fig. 8 is a view taken along the direction of arrow Z in Fig. 6. Fig. 9 is line 9-9 in Fig. 1. Sectional view [Explanation of symbols]
10: Swing arm, 12: Axle, 30: Main arm, 32: Cross member, 33: Stay, 35: Reinforcing member, 40: Maximum part, 41: Rear end part, 42: Tapered part

Claims (1)

A vehicle comprising a pair of left and right main arms having one end pivotally supported on the vehicle body and a wheel supported on the other end, a swing arm having a cross member connecting the left and right main arms, and a shock absorber connected to the cross member In the suspension system for a vehicle, a reinforcing member is disposed above the main arm and connected to the cross member and the axle support portion of the main arm to form a substantially triangular portion when viewed from the side. The main arm is formed in a tapered shape whose width is gradually narrowed from the connecting portion of the cross member toward the wheel support portion, the vicinity of the wheel support portion to which the reinforcing member is connected is a minimum cross-sectional area portion, and the reinforcing member While making the vicinity of the rear end bend downward at a steep angle ,
Said vehicle wheel support unit is an end-piece is a member for supporting the axle of the rear wheel to be welded to the rear end of the main arm, with a welded rear end of the reinforcing member to substantially the entire length of the end piece A vehicle suspension system characterized by the above.

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