JPH0370611A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To cause steering stability during low steering to be compatible with cornering ability during high steering by a method wherein the two end parts of each of a pair of upper and lower upper arms and one lower arm are coupled to respective specified portions, and the outer end part of a tie rod is coupled to the specified portion in a state to be inclined upward. CONSTITUTION:A wheel support 2 to support a wheel 1 is vertically rockably supported to a car body 6 by means of a pair of upper and lower upper arms 3 and 4 and one lower arm 5. In this case, inner and outer end parts 5b and 5a of the lower arm 5 are pivotally mounted to a lower part 6a of a car body and the lower part of the support, respectively. Two end parts 3a of the first upper arm 3 are respectively pivotally mounted to an upper part 6c of the car body and the upper part of the support. Inner and outer end parts 4b and 4a of the second upper arm 4 are pivotally mounted to a central part 6b of the car body and the central part of the support, respectively. A tie rod 18 is inclined such that an outer end part 18a is positioned above, and the outer end part 18a is coupled in a position in the rear of a king pin shaft 21 to the wheel support 2.

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 also reduces the support 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 of vehicle, either ride comfort or brake shudder had to be sacrificed, or the satisfaction level 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, due to layout constraints, etc., which will be described later, the upper arm is deviated rearward as described above, so even if an elastic bushing is inserted at its pivot point, the action of external force will If the direction shifts from the compression direction to the shear direction, there is a concern that the effect of improving longitudinal compliance and buffering the external force acting on the wheel support around the axle during braking may not be sufficient.

[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 formed at the tip of a lower arm disposed below is disposed at an angle substantially in the same plane above the lower pivot point. By providing a conceptual upper pivot point formed by the two upper arms, an instantaneous pivot axis connecting the two is formed, and the outer wheel is configured to have a negative camber when turning.
A suspension device is described that attempts to improve steering stability during turning. 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, a conceptual upper pivot point is provided at the intersection of the axes of the two upper arms, so that it gives longitudinal compliance to the wheel.
If flexible elastic bushings or the like are interposed in the vehicle body side pivot portions of both upper arms, there is a problem in that the upper pivot points may be displaced depending on the degree of impact received by each upper arm.

Furthermore, in order to improve steering stability, it is desirable that the toe characteristics be particularly good during small steering turns. In other words, when turning a small wheel, the outer turning wheel bumps while the inner turning wheel rebounds, but initially the steering wheel is made less effective, that is, the toe-out effect of the outer turning wheel is increased, resulting in a slight understeer. If the steering device is configured, stable turning maneuverability can be obtained. Furthermore, even with this configuration, it goes without saying that good turning performance can be obtained during large steering turns. Therefore, it is desirable to obtain a toe characteristic in which the amount of toe-out initially increases gradually and then gradually decreases depending on the degree of bump during turning. Regarding this point, the above-mentioned conventional examples etc. do not mention anything at all, and it is not thought that such an effect is produced.

The present invention was made in consideration of the above-mentioned circumstances, and achieves both improvement of riding comfort and prevention of brake shudder, and particularly good steering stability during small steering turns and good steering stability during large steering turns. An object of the present invention is to provide a suspension device for a vehicle that can achieve both good turning performance.

(Means for Solving the Problems) The present invention provides 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 relative to a vehicle body. In order to solve the above problem, first, 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 mounted. One end of the first upper arm, which is located above and away from the axle, is mounted above the wheel support, and the other end is pivoted at an upper height position on the vehicle body side. The first upper arm is placed in the longitudinal direction of the vehicle body, and the outer end of the second upper arm placed below the first upper arm is placed in the middle of the wheel support, and the inner end is placed on the side of the vehicle body. The second upper arm is arranged substantially in the width direction of the vehicle.

1. Connect the outer end of the tie rod to the wheel support at a position rearward of the kingpin shaft that connects the pivot point of each arm on the wheel support side.1. The tie rod is arranged with its outer end inclined slightly upward to obtain a toe-out effect of the turning outer wheel during a small steering turn, and a toe-in effect by retracting the first upper arm during a large steering turn. As a result, the amount of toe-out of the outer turning wheel is reduced.

[For production]

The displacement of the wheel support in the longitudinal direction of the vehicle body can be effectively restricted by the first assister arm, which is disposed above the axle and substantially in the longitudinal direction of the vehicle body. Therefore, by using a flexible elastic bushing at the pivot point of the first upper arm toward the vehicle body, it is possible to increase the longitudinal compliance of the wheel and improve ride comfort, as well as reduce the natural vibration of the wheel support around the axle. It is also possible to effectively provide low m buffering and prevent the occurrence of brake shudder.

The second upper arm, which regulates the displacement of the wheel support in the vehicle width direction, is located approximately in the vehicle width direction at a position below the first upper arm where there is a relatively high degree of freedom in layout. By setting the length to a suitable length, changes in camber during rocking can be reduced, and good steering stability can be obtained. Furthermore, since the first upper arm and the second upper arm are arranged at different height positions, and the upper first upper arm is arranged approximately in the longitudinal direction of the vehicle body, space is required above the inner side of the wheel. This improves the flexibility of layout.

Since the tie rod is connected to the wheel support at a position rearward of the kingpin axis with its outer end inclined slightly upward, in an equilibrium state, the tie rod corresponds to a state approximately perpendicular to the kingpin axis. , when turning,
The more the outer ring bumps, the larger the corresponding angle of the tie rod with respect to the kingpin axis becomes, and therefore the so-called steering becomes less effective. When the first upper arm disposed in the longitudinal direction of the vehicle body pulls the outer swinging wheel toward the toe-in side, the amount of toe-out caused by the tie rod is reduced and the steering becomes more effective. In other words, a toe characteristic is exhibited in which the amount of toe-out is large during a small steering turn, and the amount of toe-out is reduced during a large turning. It is possible to achieve both.

〔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. , 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 the upper height position on the vehicle body side, so that the first upper arm is attached to the vehicle body. while the outer end of the second upper arm disposed 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 disposed substantially in the vehicle width direction, it is possible to improve ride comfort and prevent brake shudder from occurring. 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.

Then, the outer end of the tie rod is connected to the wheel support at a position rearward of the kingpin axis that connects the pivot point on the wheel support side of each arm, and the tie rod is tilted slightly upward. The steering wheel is arranged so that a toe-out effect of the outer turning wheel can be obtained during a small steering turn, and at the same time, the amount of toe-out of the turning outer wheel is reduced by a toe-in effect caused by retraction of the first upper arm during a large turning. Therefore, it is possible to improve both the turning maneuverability during a small steering turn and the retrospective ability during a large steering turn.

〔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 jug during small steering turns. This system is designed to improve both the steering stability at the time of steering and the ability to turn at the time of large steering turns, and is configured as follows.

As shown in FIGS. 1(a) and (b), a wheel support 2 that rotatably supports a wheel 1 and extends upward is provided with two upper arms disposed at different height positions and in different directions. 3 and 4 and a lower arm 5 disposed below the lower arm 5, the lower arm 5 is supported by 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. It is arranged in the width direction of the vehicle.

And the wheel support 2 of each arm 3, 4.5 above.
The outer end 18a of the tie rod 18 is connected to the wheel support 2 at a rear position than the king pin shaft 21 connecting the pivot point in the example, and the tie rod 18 is connected so that the outer end 18a is located slightly upward. It is placed at an angle. This makes it possible to obtain a toe-out effect of the outer turning wheel during a small turning, and to reduce the amount of toe-out of the turning outer wheel during a large turning due to the toe-in effect caused by the retracting action of the first upper arm 3. ing. In other words, at the beginning of a turn, the amount of toe-out is gradually increased, and as the turning angle increases, the amount of toe-out is gradually decreased, thereby achieving both steering stability during small turns and retrospective performance during large turns. Improving.

To explain in detail, the lower arm 5 is formed into a substantially V-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 about a substantially vertical axis, while its two inner ends 5b and 5c are located at the lower height position 6a of the six examples of vehicle bodies.
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 freely rotatable around an axis in the approximately front-rear direction, and the upper end of the damper 11 is connected to a coil spring 10. spring 10
At the same time, it is attached to a suspension tower 13 via an elastic bush 12, so that the wheel 1 is resiliently and cushioned. In addition, in the figure, 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. The 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 is attached to a pivot point on the vehicle body 6 side relative to the pivot point 2A of the two wheel supports. The landing point 6A is set at a low position [see Figure 4]. This improves the anti-dive property during braking by setting the momentary swing center of the wheel 1, which is determined by the first upper arm 3 and the lower arm 5, toward the rear side of the wheel 1 during bumping. This is to improve the performance.

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. The second upper arm 4 extends substantially in the vehicle width direction, and has an outer end 4a. , is pivotally attached to the wheel support 2 at a position near the boss of the rim ib 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 at the middle height position 6b of the vehicle body 6.
On the bracket 16 installed on the top of the cross member 7,
It is pivotally mounted via an elastic bushing so as to be rotatable about an axis that is horizontal in the approximately front-to-back direction.

The kingpin shaft 21 connecting the pivot points of the two wheel supports of each of the arms 3, 4.5 is slightly inclined inward, and the shaft arm 2b of the wheel support 2 protrudes rearward from the kingpin shaft 21. An outer end 18a of the tie rod 18 is connected to the tip of the tie rod 18 so as to be tilted slightly upward and rotatable around a substantially vertical axis. Inner end 1 of tie rod 18
8b is swingably connected to both ends of a relay rod 22 that transmits steering force from a steering wheel (not shown). In other words, in the illustrated state where the wheel 1 does not bump, the tie rod 18 is substantially orthogonal to the kingpin shaft 21, but the more the wheel 1 bumps, the more
The tie rod 18 is connected to the wheel 1 so that the corresponding angle of the tie rod 18 to the king pin shaft 21 is increased.
The steering effect is reduced. By setting the tie rod 18 slightly shorter than the lower arm 5, a suspension geometry is created in which the wheels l toe out as the degree of bump increases, and the amount of toe out gradually increases during small steering turns. Obtains toe characteristics. Therefore, during a small steering turn, the effectiveness of the rudder can be reduced to improve steering stability. On the other hand, when the steering angle becomes larger than that, the first upper arm 3 disposed in the longitudinal direction of the vehicle body 6 pulls the upper end of the wheel support 2 toward the rear of the vehicle body to exert a toe-in effect.
The toe-out amount is gradually reduced to improve retrospective performance.

Describing the effects of the vehicle suspension system configured in this way, in terms of driving stability, it not only provides the effects of a so-called low mount upper arm type suspension system, but also improves riding comfort and brake jug. Regarding both prevention and prevention,
This exhibits the effects of the high mount upper arm system. In particular, it is possible to achieve the effect of improving both the steering stability during small steering turns and the turning performance during large turning turns. First, to explain the steering characteristics during a turn, due to the suspension geometry described above, as shown in Figure 2, at the beginning of a bump or rebound, that is, at the time of a small steering turn, the amount of toe-out or toe-in gradually increases. When the steering angle becomes large and the vehicle bumps or rebounds to an extent greater than that, a toe characteristic in which the amount of toe-out or amount of toe-in gradually decreases is exhibited.

During a small steering turn, the outer wheels 1 are in a bump state, so
As mentioned above, the tie rod 18 is connected to the king pin shaft 21
The corresponding position state is such that the corresponding angle further increases from the state where it is substantially perpendicular to the corresponding position.

In such a state, the amount of rotation of the shaft arm 2b of the wheel support 2 operated by the tie rod 18, that is, the amount of actual steering of the wheel 1, tends to decrease, and in addition to the above-mentioned toe-out effect, the effectiveness of the rudder is moderately reduced. can be made duller to improve steering stability.

On the other hand, when the vehicle is steered beyond the point where the bump becomes large and the amount of bump becomes large, the wheel 1 is deflected inward of the vehicle body (see Fig. 3), and the first upper arm 3 disposed in the longitudinal direction of the vehicle body provides wheel support. The upper end of 2 is drawn approximately backward (δ) [see Figure 4]. Therefore, a toe-in effect appears on the outer wheels 1, reducing the above-described amount of toe-out, which improves the so-called rudder effectiveness and improves turning performance.

In this way, by changing the outer turning wheel to toe-out and the inner turning wheel to toe-in during a small steering turn, the effectiveness of the rudder is moderately reduced and steering stability is improved, while during a large turning turn, the outer turning wheel is changed to toe-in. By gradually decreasing the amount of toe-out of the wheel and the amount of toe-in of the inner wheel of the turning, the effectiveness of the rudder is improved and the turning performance is improved, which improves the maneuverability during turns where there is a tendency to understeer when taking small steering turns into consideration. 6 Next, to explain in more detail the effects of the multi-link suspension, firstly, by extending the wheel support 2 that supports the wheel l upward, it is relatively rigid in the front-rear direction. The distance from the lower pivot point 5A of the outer end 5a of the lower arm 5 connected to the vehicle body 6 to the upper pivot point 2A of the one end 3a of the first upper arm 3 is increased, and the lever ratio to the axle 1a is increased. In addition, by interposing a flexible elastic bushing at the pivot point 6A on the other end 3b side of the first upper arm 3, the longitudinal compliance characteristics of the wheel 1 are improved and shocks are softly absorbed. The ride comfort can be improved. Due to the longitudinal arrangement of the first aft 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 shudder. More specifically, as shown in FIG. 5, in the high mount upper arm system of the present invention, during braking, the axle 1 receives a moment F from the ground around the axle 1a, and the first
The upper pivot point 2A, which is the pivot point with the upper arm 3, is displaced forward, and the lower pivot point 5A, which is the pivot point with the lower arm 5, is displaced rearward. 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 the brake shudder is allowed to move from the king pin axis K to B, the compliance of the first upper arm 3 is set to X2. This amount of compliance x
2 acts to improve riding comfort (see C), the amount of rearward movement at the wheel center (the center of the axle 1a) at that time is X4.

In the low mount upper arm system (the upper pivot point is indicated by H4), if the tolerance of the brake shudder during braking is up to B, the compliance of the upper arm is
1 can contribute to improving ride comfort, but the amount of rearward movement at the wheel center at that time is x3. 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 X3 in the low mount upper arm method. Therefore, when the tolerance of the brake shudder is the same, the high mount upper arm method has the difference in the amount of rearward movement (xa x3)
This means that the shock absorbing ability is excellent. In other words,
It solves the problems that conventional suspension systems could not achieve: improving ride comfort and preventing brake shudder.

In addition, since the second upper arm 4 is arranged at a lower position than the first upper arm 3, there is a relatively high degree of freedom in layout in the direction along the cross member 7 at this location.
The second assister arm 4 can be set to a sufficient length, and an excessive camber change when the wheel 1 swings can be eliminated, and good steering stability can be obtained.

Furthermore, since the first upper arm 3 is arranged at a different height from the second upper arm 4 in the longitudinal direction of the vehicle body 6, no space is required above the inner side of the wheel 1, and the degree of freedom in the layout of that part is increased. This allows for lower bonnets and larger engines. Although not shown,
The first upper arm 3 and the 27th . By incorporating a turnbuckle in each of the collar arms 4, caster adjustment and camber adjustment can be easily adjusted independently without interfering with each other.

As described above, according to the present invention, it is possible to both improve riding comfort and prevent brake jug from occurring, and in particular, to improve both steering stability during small steering turns and turning performance during large steering turns. Vehicle suspension equipment that can
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 front view of a vehicle suspension device for front wheels of the present invention, and FIG.
)) is its plan view, Fig. 2 is a graph showing toe characteristics, Fig. 3 is a schematic front view of the suspension device, Fig. 4 is a schematic side view of the suspension device, and Fig. 5 is a graph showing the ride quality. FIG. 3 is a schematic diagram for explaining how to achieve both improvement and prevention of brake shudder. 1-wheel, 2-wheel support, 3-first upper arm, 3a-11 end, 3b.-=other end, 4-.second
Upper arm, 4a-outer end, 4b-inner end, 5-o arm, 5a-outer end, 5b, 5c-inner end, 6.
・-Vehicle body, 6a-lower height position, 6b=middle height position,
6c --- Upper height position, 18-- Tie rod, 18a
-・Outer end, 21. - Kingpin axis.

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. The second upper arm is located approximately in the width direction of the vehicle, and is located rearward of the kingpin axis that connects the pivot point of each arm on the wheel support side. The outer end of the tie rod is connected to the wheel support, and the outer end of the tie rod is arranged with the outer end inclined slightly upward, so that a toe-out effect of the turning outer wheel is obtained during a small turning, and A suspension device for a vehicle, characterized in that during a large steering turn, a toe-in effect due to retraction of the first upper arm reduces the amount of toe-out of the outer turning wheel.