JP2536123B2 - Strut suspension - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strut suspension for a vehicle body, and more particularly to a suspension used for front wheel suspension and connected to a steering device.

(Prior Art) A strut suspension includes a strut upper part of a strut having an upper part of the strut and a lower part of the strut capable of relative activity with respect to the upper part of the strut so as to be swingably connected to the vehicle body, and the lower part of the strut is arranged in a lateral direction of the vehicle body. It is configured by swingably connecting to a suspension arm extending to (for example, JP-A-56-82613 and JP-A-63).
-28707 publication).

Since this suspension has features such as a small number of attachment points to the vehicle body and a lateral member that is only a suspension arm, input to the vehicle body is small and
It has advantages such as less influence of work precision on suspension geometry and less space limitation in the lateral direction. On the other hand, since there is little change in the camber of the tire when bounding, the ground outer camber of the turning outer wheel becomes large on the positive side.

By the way, in order to cope with, for example, a front-wheel drive vehicle equipped with a high-power engine, it is necessary to suppress the front wheels from trying to rotate around the kingpin axis line at the time of sudden acceleration or sudden deceleration as much as possible to ensure steering stability.

The front wheel tries to rotate backward around the kingpin axis due to the braking force acting on the center of the ground contact surface of the tire,
Further, the driving force acting at the point where the virtual vertical plane passing through the center of the tire ground contact plane intersects the tire rotation axis, and tries to rotate forward around the kingpin axis. The degree of rotation of the former depends on the magnitude of the kingpin offset given by the distance from the intersection of the kingpin axis with the contact surface to the center of the contact surface of the tire, and the degree of rotation of the latter passes through the center of the contact surface of the tire. The distance from the intersection of the virtual vertical plane and the axis of rotation of the tire to the kingpin axis depends on the size of the so-called IK distance. The distance must be zero, or as close to zero as possible.

Separately proposed strut suspension (Patent application Sho
63-220409) is a strut having a strut upper part and a strut lower part slidable relative to the strut upper part, the strut upper part is swingably connected to the vehicle body, and the strut lower part is arranged in a lateral direction of the vehicle body. A strut suspension that is swingably connected to an extending suspension arm and has a portion above and below a rotation axis of a wheel, and the upper portion swings to the lower portion of the strut via a ball joint. A wheel carrier that is movably connected, and a control that is swingably connected to the suspension arm at one end and swingably connected to the lower portion of the wheel carrier at the other end via a ball joint. Including links and. The connection point between the control link and the suspension arm is provided at a position where the suspension arm is displaced outward in the lateral direction of the vehicle body as the suspension arm swings in the bounding direction from the reference state.

The suspension can greatly change the camber, the kingpin offset can be made substantially zero, and the IK distance can be made as small as possible.

(Problems to be Solved by the Invention) When the suspension according to the above proposal is examined under running conditions, there are the following problems. That is, when the outer wheel steers in the toe-in direction during turning and becomes bound, in order to keep the ground camber angle appropriate to the rolling of the vehicle body, set the camber angle to negative and make a large camber change with bounding. Need to be done. However, when the vehicle goes into a bound state without a steer change when going straight, the camber change must be small in order to suppress the deterioration of straightness due to the canvas last.

The suspension according to the above proposal has a large change in camber and does not satisfy the latter requirement. Therefore, it is conceivable that the caster angle is set to a large value to improve the straightness, thereby compensating for the decrease in the straightness due to the large camber change. However, if the caster angle is set to a large value, the straight running stability at the time of driving is impaired, especially in the case of FF vehicles.

It is an object of the present invention to provide a strut suspension capable of increasing the camber change at the time of bouncing and simultaneously increasing the caster angle.

(Means for Solving the Problems) A strut-type suspension according to the present invention is capable of relatively sliding relative to an upper part of a strut that is swingably connected to a vehicle body, and rotatable about an axis of the upper part of the strut. A strut having a lower strut, a suspension arm extending in the lateral direction of the vehicle body to which the lower strut of the strut is swingably connected via a ball joint, and a portion above and below the rotation axis of the wheel. And a wheel carrier whose upper part is swingably connected to the lower part of the strut via a ball joint, and one end of which is swingably connected to the suspension arm, and the other end of which is At a lower portion of the wheel carrier via a ball joint so as to be swingable. It is a trawl link and the connection point with the suspension arm is
As the suspension arm swings in the bounding direction from the reference state, the first control link is provided at a position that is displaced outward in the lateral direction of the vehicle body; A second control link swingably connected to the suspension arm or the vehicle body at the end of the wheel via a ball joint, and moves the ball joint in the upper portion of the wheel carrier to the rear of the vehicle body at the time of bouncing. A second control link provided at a position where

Two preferred embodiments are given. In one aspect,
The first control link forms a rotating pair with the suspension arm at one end, that is, the inner end, and forms a spherical pair with the wheel carrier at the outer end. In this aspect, the kingpin axis is provided as a line connecting the respective centers of ball joints located above and below the wheel carrier.

In another aspect, the first control link consists of two rods. Each rod forms a spherical pair with the suspension arm at the inner end and a spherical pair with the wheel carrier at the outer end. In this aspect, the kingpin axis is given as a line connecting the center of the ball joint arranged above the wheel carrier and the intersection of the extension lines of the axes of the two rods, and is, so to speak, a virtual kingpin axis.

(Operation and Effect) When the tire becomes bound and the suspension arm swings, the strut swings, and at the same time, the first control link pushes the lower portion of the wheel carrier outward in the lateral direction of the vehicle body. The wheel carrier swings around the upper ball joint by the outward push-out by the first control link, but since the strut swing is also added to the wheel carrier, the overall swing angle is large. Then, the tire changes the camber drastically.

When the suspension arm swings, the lower part of the strut is restrained by the second control link and rotates around the axis of the upper part of the strut. The rotation of the lower part of the strut causes the ball joint above the wheel carrier to be displaced rearward, increasing the caster angle.

As the caster angle increases with the bound stroke of the tire, when a steer change occurs in the bound state,
The camber angle increases to the negative side. Therefore, in a situation where a steer change in the toe-in direction and a bound stroke occur at the same time, such as a turning outer wheel, the camber angle becomes large on the negative side, and the ground camber angle is appropriately maintained.

In the case of a bound stroke that does not involve a steer change, such as when going straight, the caster angle is increased and the straightness is improved, which compensates for the decrease in the straightness due to a large change in the camber.

When the tire bounces and the suspension arm swings, the first control link is pushed outward in the lateral direction, so that the ball joint at the joint between the first control link and the wheel carrier moves in the lateral direction. It will be displaced, and the swing angle of the ball joint will be small. This means that the ball joint can be arranged as laterally as possible outside the vehicle body without interfering with the wheel brake device.
Therefore, it is possible to reduce the kingpin offset to zero and shorten the IK distance as much as possible. As a result, when the front wheels receive a braking force or a driving force, it is possible to prevent the front wheels from attempting to rotate around the kingpin axis line, and it is possible to improve steering stability while achieving high performance.

The kingpin axis can be set independently, increasing the flexibility of suspension geometry design.

(Embodiment) The strut suspension according to the present invention is basically constructed as shown in FIG. In this suspension, the strut 10 is composed of a shock absorber having a structure known per se, and has a strut upper portion 11 and a strut lower portion 12 forming a sliding pair and a rotation pair with respect to the strut upper portion 11. A coil spring (not shown) is arranged between the strut upper portion 11 and the strut lower portion 12.

The suspension arm 14, the lower strut 12, the upper strut 11 and the vehicle body 16 form a first four-bar link. The suspension arm 14
The vehicle body 16 and the vehicle body 16 form a kinematic pair about an axis 18, and the suspension arm 14 and the lower strut 12 form a spherical pair with a ball joint 20. The upper portion 11 of the strut and the vehicle body 16 form a spherical pair with the support 22.

The suspension arm 14, the control link 24, the wheel carrier 26, and the lower strut 12 form a second four-bar link. In this four-bar link, the suspension arm 14 and the control link 24 form a rotating pair about an axis 28.

The wheel carrier 26 has a portion 33 above and a portion 34 below the rotation shaft 32 of the tire 30. The kingpin axis connects the center of a ball joint 36 where the upper part 33 of the wheel carrier and the lower part of the strut 12 form a spherical pair, and the lower part 34 of the wheel carrier and the center of a ball joint 38 where the control link 24 forms a spherical pair. Given as a connecting line.

The second control link 40 and the lower strut 12 form a spherical kinematic pair by the ball joint 42, and the control link 40 and the suspension arm 14 form a spherical kinematic pair by the ball joint 44.

FIG. 2 shows the suspension of FIG. 1 in a working state. The description of the structure of this suspension which is substantially the same as that of FIG. 1 is omitted.

The suspension arm 14 is bifurcated, and rubber bushes (not shown) are arranged at the bifurcated ends 14a and 14b. The suspension arm 14 swings on the vehicle body 16 by a shaft 18 penetrating the bushes. Connected as possible. The rotating pair of the suspension arm 14 and the vehicle body 16 about the axis 18 forms the suspension arm 14 with a substantially straight rod, while connecting the strut bar for restricting the longitudinal movement of the vehicle body to the wheel carrier 26. Can also be secured by.

A bracket 15 protruding downward is provided at a portion of the suspension arm 14 which is located inward of the ball joint 20 in the lateral direction of the vehicle body. The shaft 28 is supported by the bracket 15. On the other hand, the control link 24 is bifurcated, and rubber bushes (not shown) are arranged at the bifurcated ends 24a and 24b. The control link 24 is swingably connected to the bracket 15, and thus the suspension arm 14, by a shaft 28 passing through these bushes. As a result, a rotational pair of the suspension arm 14 and the control link 24 about the axis 28 is secured.

The connection point between the suspension arm 14 and the control link 24 is laterally outward from the vehicle body as the suspension arm 14 swings in the bounding direction from a standard state such as a state where the suspension arm 14 is not bound or rebounded during standard loading. It is provided at a position that is displaced toward.

In the illustrated embodiment, the bracket 15 is projected downward from the suspension arm 14 and the bracket 15
The above structure is secured by connecting the control link 24 via 28. In this case, the axis of the shaft 28 becomes the connecting point.

The wheel carrier 26 is a steering knuckle,
A knuckle arm 46 is provided on the upper portion 33. Knuckle arm 46 is tie rod via ball joint 48
The tie rod 50 is connected to a member such as a rack bar of a steering device (not shown) via a ball joint 52.

A bracket 54 is provided at an intermediate portion of the suspension arm 14, and the ball joint 44 is supported by the bracket 54. On the other hand, a bracket 56 is provided on the lower portion 12 of the strut, and the ball joint 42 is supported by the bracket 56. The control link 40 connects the lower strut 12 and the suspension arm via these ball joints.
It is connected to 14 and.

The ball joint 44 and the control link 40 are arranged so that when the tire 30 makes a bound stroke, the ball joint 36 moves to the rear of the vehicle to increase the caster angle.

In the embodiment shown in FIG. 6, the ball joint 44 is arranged so as to be perpendicular to the straight line connecting the center of the ball joint 20 and the center of the support 22 and above the straight line a passing through the center of the ball joint 20. Has been done. Further, the control link 40 is arranged so as to be positioned behind the vehicle (front side in the figure) with respect to a plane including a perpendicular line drawn from the center of the ball joint 20 to the shaft 18 and the center of the support 22. .

In the embodiment shown in FIG. 7, the ball joint 44 is located below the straight line a. And control link 40
Is arranged in front of the vehicle with respect to a plane including a perpendicular line drawn from the ball joint 20 to the axis 18 and the center of the support 22.

Third embodiment showing another embodiment of strut suspension
In the figure, a configuration different from the suspension shown in FIG. 2 will be described.

The first control link 70 includes a first rod 71 and a second rod 72. Both rods 71 and 72 are arranged at substantially the same level when viewed from the rear, and are equivalent to one control link. The suspension arm 14, the control link 70, the wheel carrier 26, and the strut lower portion 12 form a second four-bar link.

The suspension arm 14, the first rod 71, the wheel carrier 26, and the second rod 72 form a third four-bar link. Specifically, from the suspension arm 14,
Two arm portions, which are spaced apart in the front and rear direction, are projected downward, the rear arm portion is connected to the first rod 71 via the ball joint 74, and the front arm portion is connected to the second rod portion via the ball joint 78. Is connected to the rod 72 of the.

The lower portion 34 of the wheel carrier 26 is bifurcated,
The branched one end is connected to the first rod 71 via the ball joint 76, and the other end is connected to the ball joint 80.
Is connected to the second rod 72 via.

A straight line connecting the center of a ball joint 74 in which the first rod 71 and the suspension arm 14 form a spherical pair and the center of a ball joint 76 in which the first rod 71 and the lower portion 34 of the wheel carrier 26 form a spherical pair. , The second rod
The ball joint 78 in which the center of the ball joint 78 in which the 72 and the suspension arm 14 form a spherical pair and the second rod 72 and the lower portion 34 of the wheel carrier 26 form a spherical pair.
The intersection with the straight line connecting the center of 80 is the virtual rotation center P. The virtual rotation center P is a ball joint in rear view.
It is defined to be located laterally outward of the vehicle body from 76 and 80.

The kingpin axis is a ball joint in which the upper part 33 of the wheel carrier and the lower part 12 of the strut form a spherical pair.
It is given as a line connecting the center of 36 and the virtual rotation center P.

4 and 5 show another embodiment of the strut suspension, in which FIG. 4 is a part of FIG. 2 and FIG. 5 is a part of FIG. There is. That is, in both embodiments, the second control link 40 is swingably connected to the vehicle body 16 via the ball joint 44.

In the embodiment shown in FIG. 8, the ball joint 44 is a straight line passing through the center of the ball joint 42 perpendicular to the straight line c above the straight line c connecting the instantaneous center b of the strut lower part 12 and the vehicle body and the ball joint 42. It is arranged laterally inward of the vehicle from d. On the other hand, the control link 40
It is located in front of the vehicle with respect to a plane that includes the perpendicular from the ball joint 20 to the axis 18 and the center of the support 22.

In the embodiment shown in FIG. 9, the ball joint 44 is located below the straight line c and inward of the straight line d, and the control link 40 includes the perpendicular line from the ball joint 20 to the axis 18 and the center of the support 22. Located behind the vehicle with respect to the plane.

(Operation of Embodiment) Increase in caster angle: The second control link 40 is the suspension arm.
The operation of the embodiment connected to 14 will be described with reference to FIG. 6 in rear view. In the figure, the solid line shows the reference state and the broken line shows the bound state.

When the suspension arm 14 moves from the reference state to the bound state, the ball joint 44 becomes a ball joint.
Rotate counterclockwise about 20. At this time, since the ball joint 42 and the ball joint 44 are connected by the control link 40 and the distance therebetween is regulated, the lower strut 12 and the ball joint 20 are supported.
It rotates about the straight line that connects with 22. Lower strut
The rotation of 12 causes the ball joint 36 to be displaced rearward of the vehicle (front side in the figure). As a result, in a side view, the angle formed by the vertical line and the line connecting the ball joint 36 and the ball joint 20, that is, the caster angle increases.

The operation of the mode in which the second control link 40 is connected to the vehicle body will be described with reference to FIG. 8 in rear view.

The ball joint 42 moves around the ball joint 44 with respect to the vehicle body when the bouncing stroke occurs because the control link 40 exists. This motion is vector q
It is represented by. Assuming that there is no restraint by the control link 40, and therefore the lower strut 12 does not rotate about the straight line connecting the ball joint 20 and the support 22, the ball joint 42 moves about the instantaneous center b with respect to the vehicle body. This motion is represented by the vector r. The difference between vector q and vector r is the lower strut
12 is absorbed by rotating around a straight line connecting the ball joint 20 and the support 22. Lower strut 12
The rotation of the ball joint causes the ball joint 36 to be displaced rearward of the vehicle.

Change in camber angle: The operation of the embodiment shown in FIG. 2 will be described below with reference to FIG. 10 in a rear view and FIG. 11 showing the movement of each component with reference to the lower part of the strut. In FIG. 10 and FIG. 11, the solid line shows the reference state and the broken line shows the bound state.

When the upper part 11 of the strut is rotated by θ ₁ clockwise from the reference state around the ball joint 22 with the bounce,
The suspension arm 14 rotates counterclockwise from the reference state around the ball joint 20 with respect to the lower strut 12 by θ.
Rotate _twice . And the shaft 28 with respect to the lower part 12 of the strut
Rotate θ ₂ counterclockwise around the ball joint 20,
In order to move the ball joint 38 to the right via the control link 24, the wheel carrier 26 rotates θ ₃ clockwise with respect to the lower strut 12 from the reference state around the ball joint 36. Furthermore, the tire 30 rotates θ ₄ clockwise from the reference state.

If each angle when facing in the above-mentioned direction is positive, θ ₄
= Θ ₁ + θ ₃ is established, and θ ₄ is a camber change obtained by the present invention. With the conventional strut suspension, only a change in the camber of θ ₁ can be obtained, but according to the present invention, a change in the camber with the correction angle of the angle θ ₃ can be obtained. Correction angle θ _{3 in} this case
Is the positional relationship of the shaft 28 with respect to the ball joint 20, in other words, the distance L from the ball joint 20 to the shaft 28,
A straight line connecting the ball joint 20 and the shaft 28 is greatly influenced by an angle θ ₅ formed by a vertical line.

Next, in the conventional strut-type suspension, the swing angle of the ball joint 38 accompanying the bounce is substantially the same as the swing angle of the suspension arm 14, as shown in FIG. 11. , Smaller than conventional ones. This allows the ball joint
The 38 can be arranged as laterally as possible in the lateral direction of the vehicle body, and the kingpin tilt angle can be reduced to a required limit with the kingpin offset being zero. This means that the inter-IK distance L ₂ can be reduced.

In FIG. 12 comparing the kingpin axis of the strut suspension shown in FIG. 3 with the kingpin axis of the conventional strut suspension, in the embodiment, the kingpin axis K ₁ is located above the wheel carrier. It is given by a line connecting the center of the ball joint 36 and the virtual rotation center P. On the other hand, in the conventional one, the kingpin axis K ₂ is given by a line connecting the center of the support 22 and the center of the ball joint 90 arranged at the connecting portion between the suspension arm 14 and the lower portion of the wheel carrier 26. To be As is apparent from this figure, the kingpin offset is zero in the embodiment of FIG. 3, but is L ₁ in the conventional example. In addition, in the embodiment of FIG.
With respect to the inter-IK distance L ₂ , the conventional one has L ₃ larger than L ₂ .

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a basic structure of a strut suspension according to the present invention, FIG. 2 is a schematic diagram showing the embodiment of FIG. 1 in an operating state, and FIGS. 3 to 5 are other strut suspension suspensions. FIG. 6 is a schematic view of the embodiment, FIG. 6 is a rear view showing the change of the caster angle in the embodiment of FIG. 2, FIG. 7 is a schematic view showing the arrangement of the second control link, and FIGS. 8 and 9 are FIG. 4 is a rear view showing changes in caster angle in the embodiment of FIG. 4, FIGS. 10 and 11 are rear views showing changes in camber angle of the embodiment in FIG. 2, and FIG. 12 is an embodiment in FIG. It is a rear view which shows the kingpin axis | shaft of. 10: strut, 11: upper strut, 12: lower strut, 14: suspension arm 24: first control link, 26: wheel carrier, 40: second control link, 20, 22, 36, 38, 42, 44 : Ball joint.

Claims (1)

(57) [Claims] 1. A strut having an upper part of a strut swingably connected to a vehicle body and a lower part of the strut slidable relative to the upper part of the strut and rotatable about an axis of the upper part of the strut; The lower part of the strut is swingably connected via a ball joint, and has a suspension arm extending in the lateral direction of the vehicle body, a part above and below the axis of rotation of the wheel, and the upper part is the ball joint. A wheel carrier swingably connected to the lower part of the strut via the suspension arm and one end of the wheel carrier swingably connected to the lower part of the wheel carrier via a ball joint. The first control link is swingably connected, and the connection point with the suspension arm is As the suspension arm swings from the reference state in the bound direction, a first control link which is provided at a position displaced toward the outside of the vehicle body in the lateral direction, the strut lower at one end,
A second control link that is swingably connected to the suspension arm or the vehicle body at the other end via a ball joint, and moves the ball joint in the upper portion of the wheel carrier to the rear of the vehicle body at the time of bouncing. A strut suspension including a second control link provided at a moving position.