JPH1191325A - Double wishbone suspension system for vehicles - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To achieve both high security and maintenance of steering stability and input comfort in the longitudinal direction of a vehicle. SOLUTION: A lower arm 13 of a double wishbone type suspension device is connected to a lateral lower arm 14 whose one end is rotatably supported by a knuckle 12 and a compression arm whose one end is rotatably connected to an intermediate portion of the lateral lower arm 14. 15, the input in the front-rear direction and the lateral direction are separated, and the displacement with respect to the input in the front-rear direction of the vehicle is absorbed by the support point of the knuckle 12 of the compression arm 15 so that the input to the lateral lower arm 14 is reduced. To improve the ride comfort by reducing the lateral displacement of the vehicle and improve the steering stability, and to achieve a high level of compatibility between ensuring the steering stability and input / output in the longitudinal direction of the vehicle and maintaining the ride comfort.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double wishbone type suspension device in which a wheel support member is supported on a vehicle body by a lower arm and an upper arm.

[0002]

2. Description of the Related Art Vehicle suspension system (suspension system)
As an example, a double wishbone type suspension device in which a wheel (wheel supporting member) is supported on a vehicle body side by a lower arm and an upper arm is widely used (for example, see Japanese Patent Application Laid-Open No. 5-92710). A conventional double wishbone type suspension device will be described with reference to FIGS. FIG. 8 is a perspective view of a conventional double wishbone type suspension apparatus applied to the front wheels (steering wheels) of the vehicle, and FIG. 9 is a plan view of FIG.

As shown in FIG. 1, a front wheel 1 is rotatably supported by a knuckle 2 via a hub (not shown). At the lower end of the knuckle 2, the tip (point B) of the A-type lower arm 3 is rotatably supported around an axis extending in the up-down direction, and the other end (points A and G) of the bifurcated shape of the A-type lower arm 3 is horizontal. It is rotatably supported on the vehicle body side via a bush around an axis extending in the direction. That is, the A-type lower arm 3 is swingable in the vertical direction of the vehicle body. At the upper end of the knuckle 2, the tip of the upper arm 4 is rotatably supported around an axis extending in the vertical direction, and the other end of the upper arm 4 is freely rotatable around the axis extending in the horizontal direction toward the vehicle body via a bush. It is supported by.

On the other hand, an end (point H) of a tie rod 6 is rotatably supported on a knuckle arm 5 of the knuckle 2, and the knuckle 2 is rotated around the kingpin axis via the tie rod 6 to steer the front wheel 1. Is done. The tip of the piston rod 8 of the shock absorber 7 is supported on the vehicle body side.
The lower end of the cylinder 9 of the shock absorber 7 is supported on the upper surface of the A-shaped lower arm 3. A coil spring 10 is provided between the shock absorber 7 and the piston rod 8 and the cylinder 9.

In the above-described double wishbone type suspension device, the ground camber characteristic with respect to the suspension stroke is such that the front wheel 1 can be made substantially vertical at the time of turning, so that the steering stability at the time of turning is high. . In addition, there is an advantage that design flexibility such as a change in geometry and compliance tuning is high, and a bending moment is not applied to the shock absorber 7, so that friction is small.

[0006]

In the double wishbone type suspension apparatus provided with the A-type lower arm 3 described above, when a force S in the vehicle front-rear direction is input to the front wheel 1 as shown in FIG. The A-type lower arm 3 is about to pivot about the point. At this time, actually, both the point A and the point G cannot be simultaneously set as the rotation centers at the same time, so that the A-type lower arm 3 rotates around the virtual rotation center P point existing inside the vehicle body. Become. When the A-type lower arm 3 rotates around the virtual rotation center P, moments having different directions are generated at the points A and G, respectively.

For this reason, the tip of the A-type lower arm 3 (B
), The tie rod 6 and the A-type lower arm 3 become non-parallel between the points A and B, and the angle change of the front wheel 1 becomes large, which may deteriorate the steering stability. By increasing the stiffness of the bush at points A and G, it is possible to suppress the change in the angle of the front wheel 1 with respect to the input S in the front-rear direction of the vehicle. It will lead to worse riding comfort.

As described above, the double wishbone type suspension apparatus has an advantage that the steering stability during turning is high, but on the other hand, the steering stability against the input S in the longitudinal direction of the vehicle and the riding comfort are ensured. It was difficult to achieve a high level of maintenance. Input S in the longitudinal direction of the vehicle
Japanese Patent Application Laid-Open No. 9-99717 discloses a technique for suppressing the displacement of the front wheel 1, which is different in structure from a double wishbone type suspension having an advantage of high steering stability during turning. Things.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is a double wishbone type suspension capable of achieving a high level of compatibility between ensuring steering stability and maintaining ride comfort in response to a vehicle longitudinal input. It is intended to provide a device.

[0010]

In order to achieve the above object, according to the first aspect of the present invention, a lower arm of a double wishbone type suspension device is provided with a lateral lower arm having one end rotatably supported by a wheel supporting member. A compression arm, one end of which is rotatably connected to an intermediate portion of the lateral lower arm, and a displacement with respect to an input in the vehicle front-rear direction is absorbed by a support point of the compression arm on the vehicle body side, and a lateral displacement of the wheel support member is achieved. And improve steering stability.

[0011] The lower end of the damping device is rotatably connected to the middle of the lateral lower arm so as to improve the steering stability in a state where the lateral rigidity is secured. Further, the center axis of rotation of the compression arm with respect to the support point of the lateral lower arm and the center axis of rotation of the damping device cross each other.

[0012]

FIG. 1 is a perspective view of a double wishbone type suspension apparatus according to an embodiment of the present invention applied to a front wheel (steering wheel) of a vehicle, FIG. 2 is a side view thereof, and FIG. 4 shows a rear view, and FIG. 4 shows a plan view thereof.

As shown in the figure, the front wheel 11 is rotatably supported by a knuckle 12 via a hub (not shown).
The lower side of the knuckle 12 is connected to the vehicle body via a lower arm 13. That is, the lower end of the knuckle 12 is connected to one end (B
Point) is rotatably supported around an axis extending in the vertical direction,
The other end (point A) of the lateral lower arm 14 is rotatably supported on the vehicle body side via a bush around an axis extending in the horizontal direction.

Further, one end of the lateral lower arm 14 (B
One end (point F) of the compression arm 15 is supported rotatably around an axis extending in the vertical direction via a rubber bush 16 at an intermediate portion near the point (point), and the other end (point G) of the compression arm 15 is provided. At a support point different from the other end (point A) of the lateral lower arm 14, it is rotatably supported on the vehicle body side via a bush around an axis extending in the horizontal direction.

That is, the lower arm 13 composed of the lateral lower arm 14 and the compression arm 15
Is swingable in the vertical direction of the vehicle body.

At the upper end of the knuckle 12, the tip of an upper arm 17 is rotatably supported around an axis extending in the vertical direction, and the other end of the upper arm 17 is turned toward the vehicle body via a bush around the axis extending in the horizontal direction. It is rotatably supported. On the other hand, an end portion (point H) of a tie rod 19 is rotatably supported by a knuckle arm 18 of the knuckle 12, and the knuckle 12 is rotated around the kingpin axis via the tie rod 19 to steer the front wheel 11.

On the vehicle body side, the tip of a piston rod 22 of a shock absorber 21 is supported via an insulator 20, and a cylinder 23 of the shock absorber 21 is supported.
The base end of a fork 24 having a forked tip is fixed to the lower end of the fork 24. The tip (Fa point) of the fork 24 is rotatably supported at an intermediate portion of the lateral lower arm 14 via a rubber bush 32 around an axis extending in the horizontal direction. Further, a coil spring 25 is provided over the piston rod 22 side and the cylinder 23 side of the shock absorber 21. That is, the shock absorber 21 and the coil spring 25 constitute a damping device. By supporting the tip (Fa point) of the fork 24 on the lateral lower arm 14 via the rubber bush 32,
Road surface input of high frequency components can be attenuated.

In the embodiment described above, the fork 2
4 is supported at an intermediate portion of the lateral lower arm 14 so as to be advantageous in lateral rigidity.
If there is enough space above the fork,
May be supported by the upper arm 17.

The tip end (point Fa) of the fork 24 is located closer to point B on the opposite side of one end (point B) of the lateral lower arm 14 across one end (point F) of the compression arm 15. The direction in which the rotation center axis of one end (point F) of the compression arm 15 with respect to the lateral lower arm 14 and the rotation center axis of the tip (point Fa) of the fork 24 with respect to the lateral lower arm 14 intersect at an angle of approximately 90 degrees. Has made.

It should be noted that the support positions of the tip (point Fa) of the fork 24 and one end (point F) of the compression arm 15 can be reversed. Further, the rotation center axis of one end (point F) of the compression arm 15 with respect to the lateral lower arm 14 and the tip of the fork 24 (point Fa)
Although the rotation center axis intersects at an angle of about 90 degrees, the intersection angle is not limited to this. Further, in the above-described embodiment, the example in which the double wishbone type suspension device is applied to the support of the front wheel 11 has been described, but the present invention can be applied to the support of the rear wheel.

In the above-mentioned double wishbone type suspension apparatus, the ground camber characteristic with respect to the suspension stroke is such that the front wheel 11 can be made substantially vertical at the time of turning, so that the steering stability at the time of turning is high. . In addition, there is an advantage that design flexibility such as a change in geometry and compliance tuning is high, and a bending moment is not applied to the shock absorber 7, so that friction is small.

In addition to this, since the lower arm 13 is composed of the lateral lower arm 14 and the compression arm 15, as shown in FIG. The lateral lower arm 14 rotates about the other end (point A) as a fulcrum, and the force S in the vehicle longitudinal direction is applied to the compression arm 15.
And the input to the other end (point A) for the force S in the vehicle front-rear direction is dispersed.

Therefore, the longitudinal input of the other end (point A) of the lateral lower arm 14 to the force S in the longitudinal direction of the vehicle is reduced, and the influence of the mounting rigidity of the other end (point A) of the lateral lower arm 14 depends on the steering characteristics and riding characteristics. Less for comfort. Further, the lateral lower arm 14 and the tie rod 19 move in parallel, and the lateral displacement of the front wheel 11 decreases,
There is no danger that the change in the angle of the front wheel 11 becomes large and the steering stability deteriorates.

Therefore, by dividing the lower arm 13, the front and rear and lateral inputs are separated, and in particular, the input at the other end (point A) of the lateral lower arm 14 is reduced, and the riding comfort is improved. Also, the lateral lower arm 14 and the tie rod 1
9 is a movement in the parallel link state, the angle change of the front wheel 11 is reduced, and the straightness and the steering stability are improved. This makes it possible to take full advantage of the high steering stability during turning, which is the characteristic of the double wishbone type suspension system, to ensure steering stability against vehicle longitudinal input and maintain riding comfort. Can be compatible.

Further, since the lower end of the damping device is rotatably connected to the middle of the lateral lower arm, it is possible to improve the steering stability while securing the lateral rigidity. Furthermore, since the rotation center axis of the compression arm and the rotation center axis of the damping device with respect to the support point of the lateral lower arm cross each other, input in the vertical and horizontal directions is separated to improve steering stability and ride comfort. It can be improved.

In the above-described double wishbone type suspension device, one end (point F) of the compression arm 15 is supported on the lateral lower arm 14 via the rubber bush 16, but as shown in FIGS. One end (F) of the compression arm 15 is connected to the lateral lower arm 14 via the joint 31.
Point). Ball joint 3
Use of 1 is advantageous in terms of space.

[0027]

According to the first aspect of the present invention, the lower arm of the double wishbone type suspension device is rotated at one end to a lateral lower arm rotatably supported by a wheel support member, and at one end to an intermediate portion of the lateral lower arm. Since it is composed of a compression arm that is movably connected, the input in the front-rear direction and the lateral direction are separated, and the displacement to the input in the vehicle front-rear direction is absorbed by the support point of the compression arm on the vehicle side, and the input to the lateral lower arm is absorbed. Can be reduced. As a result, it is possible to improve the riding comfort by reducing the lateral displacement of the wheel support member and improve the steering stability, to secure the steering stability against the input in the vehicle front-rear direction and to improve the riding comfort. Can be achieved at a high level.

[Brief description of the drawings]

FIG. 1 is a perspective view of a double wishbone type suspension device according to an embodiment of the present invention applied to a front wheel (steered wheel) of a vehicle.

FIG. 2 is a side view of a double wishbone type suspension device according to an embodiment of the present invention.

FIG. 3 is a rear view of a double wishbone type suspension device according to an embodiment of the present invention.

FIG. 4 is a plan view of a double wishbone type suspension device according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a behavior at the time of front and rear input.

FIG. 6 is a side view of the compression arm showing a state where the lateral lower arm and the compression arm are connected by a ball joint.

FIG. 7 is a rear view of the lateral arm showing a state where the lateral lower arm and the compression arm are connected by a ball joint.

FIG. 8 is a perspective view of a conventional double wishbone type suspension device applied to a front wheel (steered wheel) of a vehicle.

FIG. 9 is a plan view in FIG. 8;

[Explanation of symbols]

 11 Front Wheel 12 Knuckle 13 Lower Arm 14 Lateral Lower Arm 15 Compression Arm 16 Rubber Bush 17 Upper Arm 18 Knuckle Arm 19 Tie Rod 20 Insulator 22 Piston Rod 23 Cylinder 24 Fork 25 Coil Spring 31, 32 Ball Joint

Claims (1)

[Claims] 1. A double wishbone type suspension device in which a lower side of a wheel support member and a vehicle body side are connected by a lower arm, and an upper side of the wheel support member and a vehicle body side are connected by an upper arm. A lateral lower arm rotatably supported by a wheel support member and the other end rotatably supported on the vehicle body side; and one end of the lateral lower arm rotatably connected to an intermediate portion of the lateral lower arm and the other end of the lateral lower arm A double wishbone type suspension apparatus for a vehicle, comprising: a compression arm rotatably supported on the vehicle body side at a support point different from the support point.