JP2657566B2 - Car rear suspension - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[Industrial applications]

 The present invention relates to a rear suspension of an automobile.

[Prior art and its problems]

In a vehicle suspension, a suspension arm is usually connected to a vehicle body via an elastic body such as rubber. This is because vibration transmitted from the wheels to the vehicle body is reduced by the elastic body. However, on the other hand, there is a problem that compliance steer occurs due to the elastic body.
When a lateral force or the like acts on the wheel, the wheel is displaced in the toe direction without permission due to the bending of the elastic body. Such compliance steer has a delicate effect on steering and running stability, and often causes a problem particularly in a rear-wheel suspension that is a non-steered wheel. For example, in the case of a rear suspension called a compound crank type as shown in FIG. 4, bosses c are respectively provided at the front ends of left and right arms b, b of the suspension arm a, and the bosses c, c are respectively provided. By supporting the support shaft d on the vehicle body via a rubber bush (not shown),
The suspension arm a is connected to the vehicle body. The left and right arms b, b are connected to a connecting bar e extending between them.
Are connected via However, when a lateral force acts on the wheel during turning or the like, the suspension arm a rotates around the X point due to the deflection of the rubber bush, and the turning outer wheel moves in the toe-out direction, the turning inner wheel moves in the toe-in direction, and so on. It will be displaced. As a result, the steering stability tends to be degraded due to the tendency toward opus steering. FIG. 6 of German Patent Publication No. DE 3441 560 and the related description show, as an idea to solve the above problem, a boss provided at the front end of a suspension arm in a so-called compound crank type suspension. Part, a support shaft on the vehicle body side inserted through a rubber bush therein is disposed vertically, and the rubber bush is positioned obliquely rearward inward in the vehicle width direction with respect to the support shaft, The rubber bushing is formed so as to have a portion located diagonally forward and outward in the vehicle width direction with respect to the support shaft. There has been proposed a configuration in which a spring constant with respect to a relative movement between the support shaft and the boss portion in a direction extending obliquely rearward is minimized. Certainly,
According to this idea, for example, when turning to the right, the left boss moves diagonally to the right and the right boss moves diagonally to the right, so that the entire suspension arm leans to the right, and tends to understeer. Can be. However, in the configuration of this conventional example, since both of the two portions of the rubber bush located with the support shaft narrowed in the boss portion are disposed obliquely with respect to the support shaft, the cornering input from the wheel at the time of turning is performed. Due to the force, the boss portion is unnecessarily deviated in the vehicle width direction, and the deterioration of the steering stability due to this is inevitable. That is, in the configuration of the conventional example, even if the compliance steer at the time of turning can be reduced, the overall adverse effect attributable to a decrease in the support rigidity of the entire suspension in the vehicle width direction is reduced. It does not significantly improve steering stability. The present invention was conceived under the circumstances described above, and appropriately prevents a change in wheel toe due to compliance steer while maintaining a predetermined support rigidity in the vehicle width direction of the suspension. It is another object of the present invention to provide a rear suspension configured to improve overall steering stability.

[Means for Solving the Problems]

In order to solve the above problems, the present invention employs the following technical means. That is, the rear suspension of the present invention includes a pair of left and right arms that extend in the front-rear direction of the vehicle and are supported by a boss provided at the front end of the boss provided on the support shaft of the vehicle body via a rubber bush. A suspension arm having a connection part for rigidly connecting the parts to each other, and a rear suspension of an automobile in which the respective arm parts support left and right wheels, respectively, wherein the support shaft on the vehicle body side and a boss part of each arm part And the rubber bush in each boss of the left and right arm parts, with respect to each support shaft, an inner rubber pillar portion located inward in the linear direction connecting between the support shafts And an outer rubber column located obliquely outward in the vehicle width direction with respect to each support shaft.

Function and Effect of the Invention

The suspension arm supports wheels on left and right arms extending in the front-rear direction, and a front end boss of each arm is supported on a support shaft of the vehicle body via a rubber bush. The support shaft and the boss of each arm are arranged upright in the vertical direction. When the front end boss portion of the suspension arm is connected to the support shaft via the rubber bush in this way, at the time of turning, compliance steering in the toe-out direction of the turning outer wheel and the toe-in direction of the turning inner wheel becomes a problem.
As described above. However, in the present invention, the rubber bush is provided with an inner rubber column portion which is located inward in a linear direction connecting substantially each of the support shafts with respect to each of the support shafts, and an outer rubber column portion with respect to each of the support shafts. As a result, the support shaft is narrowed so that the support shaft is narrowed, and the rubber for the relative movement between the support shaft and the boss portion in the direction extending from the vehicle width direction diagonally forward to the vehicle width diagonally rearward is narrowed. The spring constant of the bush is minimized. Thereby, when the boss moves relative to the support shaft inward in the vehicle width direction, the center of the boss moves obliquely forward while moving inward in the vehicle width direction. On the other hand, when relatively moving outward in the vehicle width direction, the center of the boss is displaced obliquely rearward while moving outward in the vehicle width direction. This is because the boss attempts to escape in a direction in which the rubber bush has a lower spring constant. The turning lateral force is an inward force in the vehicle width direction on the outer ring side.
Since the inner ring side acts as an outward force in the vehicle width direction, the boss portion is pushed inward in the vehicle width direction on the arm portion on the outer ring side of the suspension arm, and the boss portion is outwardly directed in the vehicle width direction on the arm portion on the inner ring side. Pressed. As described above, when the boss moves inward in the vehicle width direction, the center of the boss displaces diagonally forward, and when the boss moves outward in the vehicle width direction, the center of the boss moves diagonally rearward. Because it is displaced, when turning,
On the turning outer wheel side, the center of the boss tends to move obliquely inward in the vehicle width direction, and on the turning inner wheel, the center of the boss attempts to move obliquely rearward in the vehicle width direction. Since the left and right arm portions of the suspension arm are rigidly connected via the connection portion, the displacement of the center of the left and right boss portions is performed by displacing the suspension arm in the direction of displacing the outer ring in the toe-in direction and displacing the inner ring in the toe-out direction. Acts to rotate.
Due to the rotation of the suspension arm, the toe change in the toe-out direction of the outer wheel and the toe-in direction of the inner wheel can be reduced or completely eliminated. Therefore,
Compliance steer can be substantially prevented, and steering stability can be improved. Moreover, in the present invention, in order to minimize the spring constant of the rubber bush in the above-described direction, only the outer rubber column is disposed obliquely with respect to the support shaft, and the inner rubber column is disposed in the front-rear direction with respect to the support shaft. They are arranged in a linear direction that almost connects the supports without any deviation. Therefore, the lateral rigidity of the rubber bush and, consequently, the rear suspension can be secured to a predetermined value or more, which also greatly contributes to the improvement of the overall steering stability of the vehicle, especially when turning. In addition, since the support shaft and the boss portion are arranged in the vertical direction as described above, the rubber bushes of the left and right boss portions are both in the shearing direction with respect to the input in the front-back and up-down directions when the wheel goes over the bump. Is transformed into The spring constant is usually smaller in the shear direction than in the compression or tension direction. Therefore, the insulating effect against vibrations in the front-back and up-down directions is high, and the riding comfort is improved. Further, the support shaft is taken in and out vertically, and it is not necessary to secure a space for attaching and detaching the support shaft to the side of the boss portion. For example, when the fuel tank is disposed between the left and right boss portions, The capacity of the tank can be increased.

[Explanation of the embodiment]

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the suspension of the present invention
The vehicle includes a suspension arm 1 having a pair of left and right arms 2, 2 extending in the vehicle front-rear direction and a connecting portion 3 for rigidly connecting the left and right arms 2, 2. Bosses 4 are provided at the front ends of the left and right arms 2,2. As shown in FIG. 1 and FIG. 3, the suspension arm 1 is attached to a vehicle body-side support shaft 5 via a rubber bush 6 so that the suspension arm 1 is supported on the vehicle body. connect. The boss 4
Are also arranged in the vertical direction in accordance with the support shaft 5. Also,
The support shaft 5 has a bolt shaft shape, is fixed to the blanket 7, and has an inner cylinder 8 interposed between the support shaft 5 and the rubber bush 6. Each of the arms 2 is further provided with a wheel spindle 9. The wheel W is supported by the wheel spindle 9 via a bearing (not shown) or the like. The connecting portion 3 has a bar shape, and has a boss portion.
Behind the arm 4, the arm 2 extends between the left and right arms 2, and is rigidly connected to each arm 2 by welding or the like. In the invention of the present application, as described below, the rubber bush 6 narrows the support shaft 5 and extends from the diagonally inward front in the vehicle width direction to the diagonally rearward in the vehicle width direction. It is formed such that the spring constant with respect to the relative movement between the shaft 4 and the support shaft 5 is minimized. That is, as shown in FIGS. 1 and 2, the rubber bush 6 has a non-cylindrical structure. Specifically, the rubber bush 6 is provided with an outer rubber column portion 10a and an inner rubber column portion 10b with the support shaft 5 narrowed, and the outer rubber column portion 10a is
And the inner rubber column 10b is
Are disposed so as not to be displaced in the front-rear direction, that is, in a linear direction that connects the left and right support shafts. Then, portions other than the rubber pillar portions 10a and 10b in the boss portion 4 are voids. Therefore, when the boss portion 4 moves relative to the support shaft 5 inward in the vehicle width direction, the boss portion 4 moves in a direction in which the outer rubber column portion 10a is bent obliquely forward and deformed. Is displaced diagonally forward inward in the vehicle width direction. This is because the outer rubber column 10a is inclined obliquely forward, and therefore has a small spring constant with respect to movement in the direction in which it is bent. On the other hand, when the boss portion 4 moves relative to the support shaft 5 outward in the vehicle width direction, the boss portion 4 moves the center of the boss portion 4 in a direction to displace obliquely outward and rearward in the vehicle width direction. This is because the oblique rear portion of the support shaft 5 outward in the vehicle width direction is a gap, and the spring constant for movement in that direction is small. When the gap is provided as described above, it is preferable that at least the support shaft 5 is narrowed so that a gap is formed between the diagonally inward front part in the vehicle width direction and the diagonally rear part outward in the vehicle width direction. By the way, at the time of turning, the compliance steer in the toe-out direction (the arrow O direction in FIG. 4) on the turning outer wheel side and the toe-in direction (the arrow I direction in FIG. 4) on the inside of the turning due to the bending of the rubber bush caused by the turning lateral force. Is a problem. However, in the present invention, as described above, when the boss portion 4 moves inward in the vehicle width direction, the center of the boss portion easily moves in a direction in which the boss portion is displaced diagonally forward, and the boss portion 4 moves outward in the vehicle width direction. In some cases, the center of the boss is easily moved in a direction displaced obliquely rearward. The turning lateral force acts as an inward force in the vehicle width direction on the outer wheel side, and acts as an outward force in the vehicle width direction on the inner wheel side. For example, in the case of a left turn, as shown in FIG. 2, the boss portion 4 on the turning outer wheel side (the right arm portion 2 side) pushed inward in the vehicle width direction has the center of the boss portion at the point A (support). An attempt is made to move in a direction of displacing from the center of the shaft 5) to an arbitrary point (point C) in a diagonally forward direction inward in the vehicle width direction. On the other hand, the boss portion 4 on the turning inner wheel side (the left arm portion 2 side) pushed outward in the vehicle width direction has the center of the boss portion as B
An attempt is made to move in a direction to displace from a point (the axis of the support shaft 5) to an arbitrary point (point D) in a direction outward and diagonally rearward in the vehicle width direction. The left and right arms 2 are rigidly connected by a connecting portion 3. Therefore, the following displacement of the center of the left and right boss portions acts as a movement for displacing the turning outer wheel in the toe-in direction and rotating the suspension arm 1 in a direction for displacing the turning inner wheel in the toe-out direction.
In this way, since the toe change in the toe-out direction on the outer wheel side and the toe-in direction on the inner wheel side can be reduced or completely eliminated, compliance steer can be substantially prevented and steering stability is improved. Can be. Moreover, in the present invention, in order to minimize the spring constant of the rubber bush 6 in the above-described direction, the outer rubber column 10a
Only the diagonal direction is arranged with respect to the support shaft 5, and the inner rubber column
10b is disposed inside the support shaft 5 without being displaced in the front-rear direction with respect to the support shaft 5, so that the lateral rigidity of the rubber bush 6 and, consequently, the rear suspension can be secured to a predetermined level or more. This can also greatly contribute to improving the overall steering stability of the vehicle. That is, unnecessary movement of the boss portion 4 in the vehicle width direction with respect to the support shaft 5 due to the action of the cornering force during turning can be suppressed, and compliance steer can be substantially prevented. Steering stability at the ship is further enhanced. In addition, the spring constant is usually smaller in the shear direction than in the compression or tension direction. In the case of the present invention, the support shaft 5 and the boss portion 4 are arranged in a vertical direction.
The rubber bushes 6, 6 of the left and right boss portions 4, 4 are both deformed in the shearing direction. Therefore, the insulation effect against the front-back and up-down vibrations is high, and the riding comfort is improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a suspension according to an embodiment of the present invention, FIG. 2 is an explanatory view of the operation of the embodiment, and a cross-sectional view of a boss portion of the suspension arm. FIG.
FIG. 4 is a view corresponding to a section taken along the line III of FIG. 1 ... suspension arm, 2 ... arm part, 3 ...
Connecting part, 4 ... Boss part, 5 ... Support shaft, 6 ... Rubber bush.

Claims (1)

(57) [Claims] 1. A pair of right and left arms extending in the front-rear direction of a vehicle and having a boss provided at a front end thereof supported by a support shaft on the vehicle body side via a rubber bush. A suspension arm having a connection portion for rigidly connecting the vehicle to the vehicle, wherein each of the arm portions supports left and right wheels, respectively, wherein the support shaft on the vehicle body side and the boss portion of each of the arm portions are arranged in a vertical direction. The rubber bush in each boss portion of the left and right arm portions is provided with an inner rubber column portion located substantially inward in a linear direction that connects between the support shafts with respect to the support shafts, and A rear suspension for an automobile, comprising: an outer rubber column located obliquely outward in a vehicle width direction with respect to a support shaft.