JPH0370609A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To improve steering stability during lower steering by a method wherein a pair of upper and lower upper arms and one lower arm are arranged in the specified direction of a car body, and the outer end part of the lower upper arm is inclined forward. CONSTITUTION:A wheel 1 is vertically rockably supported to a car body 6 by means of a plurality of vertically disposed upper arms 3 and 4 and one lower arm 5 arranged therebelow. In this case, the lower arm 5 is arranged in the direction of the width of a car, an outer end part 5a thereof is pivotally mounted to the lower part of a wheel support 2 and an inner end part 5b thereof to a lower part 6a of a car body. The first upper arm 3 is arranged in the longitudinal direction of the car body, the one end part 3a thereof is pivotally mounted to the upper part of the support 2 and the other end part of an upper part 6c of the car body. The second upper arm 4 is arranged in the direction of the width of a car in a state that an outer end part 4a is inclined forward, the outer end part 4a is pivotally supported to the central part of the support 2 and an inner end part 4b to a central part 6b of the car body.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a suspension device for a vehicle.
The present invention relates to a suspension device installed in a vehicle such as an automobile in which a lower arm and a plurality of upper arms swingably support wheels.

[Conventional technology]

In the case of an independent suspension type automobile suspension system, for example, as described in Japanese Utility Model Application Publication No. 62-187904, there is a link composed of an upper arm and a lower arm that are arranged vertically and approximately parallel to each other in the vehicle width direction. According to
There is a so-called double wishbone type suspension device that supports the wheels. In this type, the upper arm and lower arm are each approximately A-shaped, and by appropriately setting the dimensions and mounting positions of each, it is possible to reduce the scoot when starting, and the camber changes and scuff changes caused by the vertical movement of the wheels. It has the advantage of being able to be made small.

On the other hand, in this type, both arms are pivotally attached to the vehicle body at two points in the front and back, so the support rigidity in the front and rear direction is high. Therefore, there is a problem in that the front-rear impact load that acts on the wheels due to undulations and unevenness of the road surface while driving tends to affect the vehicle body. In order to solve this problem, a method can be considered in which flexible elastic bushings are interposed between the two pivot points of both arms to reduce the supporting rigidity of the wheel in the longitudinal direction. However, doing so will also reduce the supporting rigidity of the wheel support around the axle, lowering its natural frequency and causing so-called brake shudder, where the wheel support resonates with the wheels, brake discs, etc. during braking. There are concerns. Therefore, with this type, either ride comfort or brake jug had to be sacrificed, or the satisfaction levels of both had to be reduced to a level where they were balanced.

In view of this, for example, Japanese Utility Model Publication No. 62-1762 discloses a so-called high mount type in which the wheel support extends above the wheel and the tip of the upper arm, which is offset backward, is attached to the extended part. Proposed. However, in this example, although the wheel support extends upward, the upper arm is arranged at an angle to accommodate loads in the vehicle width direction, so an elastic bushing is inserted at the pivot point on the vehicle body side. However, there is a concern that the effect contributing to improving longitudinal compliance characteristics may not be sufficient because the direction of action of the external force deviates from the compression direction to the shear direction. In addition, regarding the prevention of brake shudder during braking, due to the deflection arrangement of the upper arm, it is not sufficient to respond to the external force around the axle that acts on the wheel support during braking, and it is difficult to expect a significant effect. .

[Problem to be solved by the invention]

By the way, a relatively large space is required above and around the inside of the wheel because various parts are placed above the wheel to allow the wheel to move up and down, and inside the wheel. It is said that Therefore, in the above-described conventional high-mount type, the dimensions and layout of the upper arm are restricted, and as described above, the upper arm itself is relatively short and arranged at an angle. As a result, if the wheel does not have a sufficient vertical stroke or if the wheel swings violently, the camber change becomes excessive and there is a concern that another problem may arise in that the steering stability is affected.

In order to obtain good steering stability, in addition to ensuring that the camber change during rocking does not become excessive, it is also necessary to prevent It is desirable that sufficient camber rigidity be exhibited during small steering turns. To this end, it is conceivable to arrange the upper arm so as to substantially coincide with the axis of the steered outer wheel, thereby improving the lateral support rigidity for the outer wheel at that time. Regarding this point, the above-mentioned high mount type is not effective because the upper arm is deviated rearward.

Furthermore, Japanese Patent Application Laid-Open No. 58-67508 discloses that a lower pivot point is disposed at an angle substantially in the same plane above a lower pivot point formed at the tip of a lower arm disposed below. By providing a conceptual upper pivot point formed by the two upper arms, an instantaneous pivot axis connecting them is formed, and the outer wheel is configured to have a negative camber when turning. A suspension device that attempts to improve steering stability is described. However, since this device has two upper arms on the same plane, the length and surrounding layout of the upper arms are more restricted than the previously cited high-mount type. Become. In addition, since the conceptual upper pivot point is provided at the intersection of the axes of the two upper arms, flexible elastic bushings etc. are attached to the vehicle body side pivot points of both upper arms to give longitudinal compliance to the wheels. If this is installed, there is a concern that the position of the upper pivot point may shift depending on the degree of impact received by each upper arm, which may affect steering stability.

The present invention has been made in consideration of the above-mentioned circumstances, and has achieved both improved ride comfort and prevention of brake shudder, as well as improved steering stability, especially during small steering turns. Our objective is to provide a suspension device for a vehicle.

[Means to solve the problem]

The present invention solves the above problems with a suspension device in which a wheel support that rotatably supports a wheel is supported by a lower arm and a plurality of upper arms so as to be able to swing vertically with respect to a vehicle body. For this purpose, first, the outer end of the lower arm is pivotally connected to the lower part of the wheel support, and the rear end is pivotally connected to a lower height position on the vehicle body side, and the lower arm is arranged in the vehicle width direction. One end of the first upper arm disposed at an upper position away from the axle is pivotally connected to the upper part of the wheel support, and the other end is pivotally connected to an upper height position on the vehicle body side,
The first upper arm is arranged in the longitudinal direction of the vehicle body, and the second upper arm is arranged below the first upper arm.
The outer end of the upper arm is pivoted to the middle part of the wheel support, and the inner end thereof is pivoted to the middle height position on the vehicle body side, and the second upper arm is pivoted so that the outer end part is tilted forward. It is placed in the width direction of the vehicle.

[For production]

The second upper arm, which is placed above the lower arm with its outer end inclined forward in the vehicle width direction, restricts the displacement of the wheel support in the vehicle width direction, resulting in particularly good steering stability. During the required small turning, the second upper arm is moved along the axis of the outer wheel, thereby effectively improving the camber rigidity. Since this second upper arm is placed in a lower position that is different from the first upper arm and has a relatively flexible layout, the second upper arm can be set to a sufficient length and It is also possible to obtain good steering stability when traveling straight by preventing the camber change from becoming excessive.

The displacement of the wheel support in the longitudinal direction of the vehicle body can be effectively restricted by the first upper arm, which is placed in the longitudinal direction of the vehicle body at a position above and away from the axle. By using elastic bushings, the front and rear compliance of the wheels can be increased to improve riding comfort. Moreover, the elastic characteristics of the elastic bushing can effectively reduce and buffer the natural vibration of the wheel support around the axle, thereby preventing the occurrence of brake shudder. Furthermore, although the outer end of the second auber arm is inclined toward the front of the vehicle body, it is connected to the wheel support at a relatively low position, so that the brake shudder does not affect the wheel support in the vehicle width direction. Displacement can be kept small and does not cause a decrease in running stability.

Since the first upper arm and the second upper arm are arranged at different height positions, and the upper first upper arm is arranged in the longitudinal direction of the vehicle body, no space is required above the inner side of the wheel. The degree of freedom in layout is improved.

〔Effect of the invention〕

In the vehicle suspension device of the present invention, the outer end of the lower arm is pivoted to the lower part of the wheel support, and the inner end thereof is pivoted to a lower height position on the vehicle body side, and the lower arm is disposed in the vehicle width direction. The front end of the first upper arm, which is disposed above and away from the axle, is pivotally connected to the upper part of the wheel support, and the rear end is pivotally connected to the upper height position on the vehicle body side, so that the first upper arm is attached to the vehicle body. The second upper arm is arranged in the front-rear direction, and the outer end of the second upper arm arranged below the first upper arm is pivoted to the middle part of the wheel support, and the inner end thereof is pivoted to the middle height position on the vehicle body side. Since the second upper arm is arranged substantially in the vehicle width direction with the outer end inclined forward,
It is possible to both improve ride comfort and prevent brake jug from occurring, and to reduce camber changes during rocking to obtain good steering stability when traveling straight. In addition, the degree of freedom in the layout above the inside of the wheels is improved, allowing for a lower bonnet, a more compact engine room, or a larger engine. In particular, the camber rigidity of the outer turning wheel can be improved during small turns when steering stability is required.

〔Example〕

The present invention will be described in detail below based on examples thereof.

The vehicle suspension device shown in this embodiment is a multi-link suspension device that combines multiple link members three-dimensionally, and is capable of improving both ride comfort and preventing brake shudder, while also improving the ability to handle small steering movements. It is designed to improve steering stability and is constructed as follows.

As shown in FIGS. 1(a) and 1(b), a wheel support 2 that rotatably supports a wheel l and extends upwardly has two wheel supports 1 and 1 disposed in different directions at different height positions (upper and lower). The upper arms 3 and 4 and the lower arm 5 disposed below the upper arms 3 and 4 support the vehicle body 6 so as to be able to swing up and down. That is, the outer end 5a of the lower arm 5 is
At the bottom of the wheel support 2, its inner end 5b is attached to the vehicle body 6.
The lower arms 5 of the lower arms 5 are arranged in the width direction of the vehicle. On the other hand, one end 3a of the first upper arm 3 disposed above is pivoted to the upper part of the wheel support 2, and the other end 3b is pivoted to the upper height position 6C on the vehicle body 6 side. It is arranged substantially in the longitudinal direction of the vehicle body 6. The outer end 4a of the second upper arm 4 disposed below is pivoted to the middle part of the wheel support 2, and the inner end 4b thereof is pivoted to the middle height position 6b of the vehicle body 6. The outer end portion 4a is arranged substantially in the vehicle width direction with the outer end portion 4a tilted forward.

To explain in detail, the lower arm 5 is formed into a substantially square shape by combining shaft members 51 and 52, and its outer end 5a is
The wheel support 2 is pivotally attached to the lower part of the wheel support 2 via an elastic bushing so as to be rotatable around a substantially vertical axis, while its two inner ends 5b and 5c are located at a lower height position 6a on the vehicle body 6 side.
Bracket 8 installed at the bottom of cross member 7
．． 9 through elastic bushings so that the outer end 5a can swing up and down about the inner ends 5b and 5c. The lower end of a damper 11 equipped with a coil spring 10 is pivotally attached to a position near the outer end 5a of one shaft member 51 so as to be rotatable about an axis in the substantially front-back direction, and the upper end of the damper 11 is coil spring 1
0 and is attached to a suspension tower 13 via an elastic bushing 12, so that the wheel 1 is resiliently and cushioned. In addition, in the figure, 18 is a tie rod, and 19 is a stabilizer.

The first upper arm 3 is for regulating displacement of the wheel support 2 in the front-rear direction, and one end portion 3a thereof is pivotably attached to the upper end of the extension portion 2a of the wheel support 2 about an axis substantially perpendicular to the upper end. On the other hand, the other end portion 3b is pivotally connected to a bracket 20 provided at an upper portion of the rear portion of the wheel house inner 14 via an elastic bushing so as to be freely rotatable about an axis in a substantially horizontal and lateral direction. In the case of front wheel suspension, this first upper arm 3 extends rearward from the wheel support 2 substantially in the longitudinal direction of the vehicle body at a position above the top end of the wheel 1, and extends from the pivot point 2A on the side of the wheel support 2. The pivot point 6A on the vehicle body 6 side is set at a low position (see Figure 3). This is to improve anti-dive performance during braking by setting the momentary rocking center of the wheel 1, which is determined by the first upper arm 3 and lower arm 5, toward the rear when bumping. It is.

The second upper arm 4 is disposed below the first upper arm 3 and is provided to restrict lateral displacement of the wheel support 2, and is inclined by a small angle θ with respect to the axle 1a when traveling straight. , the outer end portion 4a is slightly inclined forward and extends substantially in the vehicle width direction as a whole, and the tip portion 4a is
It is pivotally attached to the wheel support 2 at a position near the top of the rim 1b of the wheel 1 via an elastic bushing so as to be rotatable around a substantially vertical axis. On the other hand, the inner end 4b is
It is pivotally connected to a bracket 16 erected on the upper part of the cross member 7, which is located at a middle height position 6b of the vehicle body 6, via an elastic bushing so as to be freely rotatable about an axis horizontal to the longitudinal direction.

To describe the effects of the suspension system for vehicles that are bottomed out as described above, in terms of running stability,
It provides the effects of a so-called low mount upper arm type suspension device, and also provides the effects of a high mount upper arm type in terms of improving riding comfort and preventing brake jug. Further, by improving the camber rigidity of the outer turning wheel during small steering, good steering stability can be obtained. That is, as shown in FIG. 2, the second upper arm 4, which regulates the displacement of the wheel support 2 in the vehicle width direction, together with the lower arm 5, is arranged as described above so as to be able to cope with the inclination of the outer wheel 1 during a small turning. As such, the distal end portion 4a is tilted forward, and the entire body is disposed slightly forward and inclined by θ with respect to the axle shaft 1a. This θ is set to a value that allows the second upper arm 4 to most effectively receive the external force received from the outer wheels 1 during so-called small steering, where steering stability is most required. In other words, in order to obtain particularly sufficient camber rigidity in the range up to the steering angle of 2θ at the time of small steering, the second upper arm 4 is placed approximately along the direction of the axle shaft 1a, which is the direction in which the external force is applied at that time. are placed.

Next, to explain in more detail the effects of the multi-link suspension exhibited by this device, firstly, by extending the wheel supports 2 that support the wheels 1 upward, the vehicle body 6 can be relatively rigid in the longitudinal direction. Lower pivot point 5A of outer end 5a of lower arm 5 to be connected
From upper pivot point 2A of one end 3a of first upper arm 3
The lever ratio to the axle 1a is increased, and the other end 3 of the first upper arm 3 is increased.
By interposing a flexible elastic bushing at the pivot point 6A on the b side, the longitudinal compliance characteristics of the wheel 1 can be improved, shocks can be softly absorbed, and riding comfort can be improved. Due to the longitudinal arrangement of the first upper arm 3 having a long lever ratio, during braking, the external force around the axle shaft 1a acting on the wheel support 2 is applied in the compression direction of the elastic bushing, thereby causing the natural vibration of the wheel support 2. It is also possible to effectively reduce and buffer the brakes and prevent the occurrence of brake jug. More specifically, as shown in FIG. 4, in the high mount upper arm system of the present invention, during braking, the wheel l receives a moment F from the ground around the axle 1a, and the first upper arm on the wheel support 2 The upper pivot point 2A, which is the pivot point with the lower arm 5, is displaced forward, and the lower pivot point 5A, which is the pivot point with the lower arm 5, is displaced backward. On the other hand, when the vehicle runs onto a stone or the like, both the upper pivot point 2A and the lower pivot point 5A are displaced rearward. Therefore, when allowing brake shudder from king pin axis K to B, the compliance of first upper arm 3 is set to X2. This amount of compliance χ works to improve the ride comfort (see C), and the wheel center (axle 1a
The amount of backward movement at the center) is X4.

In the low mount upper arm system (the upper pivot point is indicated by HL), if the tolerance of the brake shudder during braking is up to B, the compliance of the upper arm is
, will contribute to improving ride comfort, but the amount of rearward movement at the wheel center at that time will be X. As is clear from the figure, the amount of backward movement x4 in the high mount upper arm method is larger than the amount of backward movement X in the low mount upper arm method. Therefore, if the tolerance of the brake shudder is the same, the high mount upper arm method is better than the above-mentioned difference in rearward movement amount (X4 X3)
This means that the shock absorbing ability is excellent. In other words,
It improves ride comfort and solves problems that could not be achieved with playpencillan devices. In addition, the second upper arm 4
Although the outer end 4a of the upper arm 4a is arranged slightly inclined toward the front of the vehicle body, it is connected to the wheel support 2 at a position considerably lower than the first upper arm 3, so that the wheel support 20 of the vehicle body by the brake jug is Displacement in the width direction can be suppressed to a small level and does not cause a decrease in running stability.

In addition, since the second upper arm 4 is arranged at a lower position than the first upper arm 3, this part is not subject to space constraints due to the arrangement of the engine, etc., and the cross member 7
There is relatively more freedom in layout in the direction along the
The upper arm 4 can be set to a sufficient length, and excessive camber changes can be eliminated when the wheels 1 swing, thereby achieving good steering stability.

Furthermore, since the first upper arm 3 is arranged in the front-rear direction of the vehicle body 6 at a different height from the second upper arm 4, no space is required above the inner side of the wheel 1, and the flexibility of the layout of that part is increased. This allows for lower bonnets and larger engines. Although not shown,
By incorporating turnbuckles into the first upper arm 3 and the second upper arm 4, the caster adjustment and the camber adjustment can be easily adjusted independently without interfering with each other.

As described above, according to the present invention, there is provided a suspension device for a vehicle that is capable of improving steering stability, especially during small turning, and is capable of simultaneously improving riding comfort and preventing the occurrence of brake shudder. It can be configured without impairing the freedom of layout around the wheels.

[Brief explanation of drawings]

The drawings show embodiments of the present invention, and FIG. 1(a) is a plan view of a vehicle suspension device for front wheels of the present invention.
b) is a front view, Fig. 2 is a schematic plan view, Fig. 3 is a schematic side view seen from the inside, and Fig. 4 is a schematic diagram to explain how to improve riding comfort and prevent brake jug. It is a diagram. 1-wheel, 2-wheel support, 3...-first upper arm, 3a=---one end, 3b-other end, 4-
Second upper arm, 4a-outer end, 4b-inner end, 5-
Lower arm, 5a--outer end, 5b, 5c-inner end, 6
--Vehicle body, 6a--lower height position, 6b--middle height position, 6c=--upper height position. Figure 1 (b) 5a (5A)

Claims (1)

[Claims] (1) A wheel support that rotatably supports the wheel and extends upward, with a lower arm and a plurality of upper arms,
In a suspension device that supports a vehicle body so as to be able to swing vertically, an outer end of the lower arm is pivotally connected to a lower part of the wheel support, and an inner end thereof is pivotally connected to a lower height position on the vehicle body side. The lower arm is arranged in the vehicle width direction, and one end of the first upper arm, which is located above the axle, is located above the wheel support, and the other end is located at an upper height position on the vehicle body side. The first upper arm is arranged in the longitudinal direction of the vehicle body, while the outer end of the second upper arm arranged below the first upper arm is attached to the middle part of the wheel support, and the inner end thereof is arranged in the longitudinal direction of the vehicle body. A suspension device for a vehicle, characterized in that the second upper arm is arranged approximately in the width direction of the vehicle with its outer end tilted forward. .