JPH05201218A - Suspension for vehicle - Google Patents

Abstract

PURPOSE:To prevent a worsening of return of a steering wheel at the time of its operation by providing a sub link for pressing an inner end in the car width direction of a rear lower arm to the rear corresponding to displacement of an outer end in the car width direction of a rear lower arm. CONSTITUTION:A knuckle 6 is supported in the vertical direction by a car body through a front lower arm 1 and a rear lower arm 2 in capable of oscillation, and a lower set point KD of a virtual king pin axis KP is constituted by an extended intersection outside the car body between the front lower arm 1 and the rear lower arm 2. And an inner end in the car width direction of the rear lower arm 2 is connected to the car body through a slide bush 10 in capable of sliding in the longitudinal direction of the car body. And an intermediate part of the rear lower arm 2 is connected to the car body by a sub link 25, and the inner end in the car width direction of the rear lower arm 2 is also displaced to the rear when an outer end in the car width direction of the rear lower arm 2 is displaced to rear. By this, the extended intersection outside the car body between the front and rear lower arms is located relatively front, a reduction amount of a caster trail is reduced and deterioration in returning of a steering wheel can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle suspension device.

[0002]

2. Description of the Related Art A wheel supporting member for a steered wheel, that is, a knuckle is supported by a vehicle body through at least a lower arm so as to be vertically swingable. The wheels attached to the wheel support member are required to be set so as to have a predetermined wheel alignment, and the kingpin shaft is one of the important factors for determining the wheel alignment.

That is, when viewed from the front (rear) of the vehicle body, the downward extension line of the kingpin shaft is located slightly outward of the widthwise center line of the wheel body so that the wheel may move when braking. It is desired to be in. Further, the kingpin shaft is located slightly inward of the widthwise center line of the wheel inward of the vehicle body at the rotation center height position of the wheel so that the wheel becomes a toe-in when receiving a driving force. It is desirable to do. Such a setting is strongly required especially for the front suspension of an FF vehicle equipped with an engine that generates a large torque.

As can be understood from the above description, the kingpin shaft is required to be set slightly inclined so that it is located toward the outer side of the vehicle body as it goes downward when viewed from the front of the vehicle body. For example, in a strut suspension, the connecting portion between the lower arm and the wheel supporting member constitutes the lower set point, and the connecting portion between the suspension damper and the wheel supporting member constitutes the upper set point, and both of the above setting points are set. The line connecting the points is the kingpin axis.

In order to satisfy the above-mentioned demand for tilting of the kingpin shaft, the lower setting point, that is, the outer end of the lower arm in the vehicle width direction is deeply extended to the inner diameter portion of the wheel, that is, greatly extended outward in the vehicle width direction. However, from the standpoint of preventing interference with break disks, etc.
It is practically difficult to extend the frame to the outer side in the circumferential direction of the vehicle.

In order to position the lower set point of the kingpin shaft to the outer side in the vehicle width direction more sufficiently, the lower arm is divided into a front lower arm and a rear lower arm, and the wheel support member and the lower arm are arranged. A so-called double-pivot type suspension having two connecting portions with the frame has been proposed (see Japanese Patent Publication No. 58-42042). That is, the lower set point of the virtual kingpin axis is to be configured by the intersection point of the front lower arm and the rear lower arm that extends outward of the vehicle body. More specifically, the line connecting the vehicle body side connecting portion of the front lower arm and the wheel supporting member side connecting portion and the line connecting the vehicle body side connecting portion of the rear lower arm and the wheel supporting member side connecting portion By arranging the intersection point on the outer end side in the vehicle width direction with respect to the connecting portion of each lower arm with respect to the wheel support member, the intersection point is substantially configured as a lower set point of the virtual kingpin axis. is there.

[0007]

However, in the structure in which the virtual kingpin shaft is formed by dividing the lower arm into the front lower arm and the rear lower arm, the steering wheel is turned when the steering wheel is steered. It has been found that the caster trail of the wheel on the side of the turning outer wheel becomes smaller and the return of the steering wheel becomes worse.

Explaining this point in detail, when the steering wheel is turned, the outer wheel is steered about the virtual kingpin axis when it is in a straight traveling state. When this steered,
The connecting portions of the front lower arm and the rear lower arm to the wheel supporting member are displaced relatively rearward as compared with the straight traveling state, whereby each lower arm swings rearward of the vehicle body. As a result, the lower set point of the virtual kingpin axis is displaced rearward, resulting in a smaller caster trail and poorer handle return. In particular, the turning outer wheel is the wheel on the side that substantially controls the return of the steering wheel due to the movement of the load on the vehicle body, so the steering wheel return wheel is operated at high speed and at a large steering angle such as during sports driving. The deterioration was considerable, and in extreme cases, the wheels would be steered more than intended.

The present invention has been made in consideration of the above circumstances, and in which the front lower arm and the rear lower arm constitute the lower set point of the virtual kingpin shaft, the handle is returned. An object of the present invention is to provide a vehicle suspension device that can reduce deterioration.

[0010]

In order to achieve the above-mentioned object, the present invention has the following first structure. That is, the wheel support member for the steered wheels is swingably supported by the vehicle body in the vertical direction via the front lower arm and the rear lower arm,
In a vehicle suspension device in which a lower set point of a virtual kingpin axis is constituted by an intersection of the front lower arm and a rear lower arm extending outward from the vehicle body, an inner end portion of the rear lower arm in a vehicle width direction. Is connected to the vehicle body so as to be slidable in the front-rear direction of the vehicle body, connects the intermediate portion of the rear lower arm and the vehicle body, and responds to the rearward displacement of the outer end portion of the rear lower arm in the vehicle width direction. The rear lower arm is provided with a sub-link for pushing the inner end of the rear lower arm in the vehicle width direction rearward.

In order to achieve the above object, the present invention has the following second construction. That is, the wheel support member is swingably supported on the vehicle body in the up-down direction via the front lower arm and the rear lower arm, and is extended by the outward extension intersection of the front lower arm and the rear lower arm. In a vehicle suspension device configured to form a lower set point of a virtual kingpin axis, a vehicle with an assist link mounted on a vehicle body such that an inner end portion of the rear lower arm in the vehicle width direction is swingable in a vehicle front-rear direction. The rear lower arm is connected to the outer end in the width direction, connects the intermediate portion of the rear lower arm and the vehicle body, and the rear lower arm is displaced in response to the rearward displacement of the outer end of the rear lower arm in the vehicle width direction. A sub-link for pressing the inner end of the vehicle in the vehicle width direction to the rear is provided.

In the suspension device according to the present invention, it is possible to connect the suspension damper and the wheel supporting member via the upper arm without directly connecting the suspension damper and the wheel supporting member. The lower end of the suspension damper may be connected to a lower arm, for example, a front lower arm.

[0013]

According to the present invention, the inner end of the rear lower arm for the steered turning outer wheel in the vehicle width direction is largely displaced rearward, and as a result, the vehicle body including the front lower arm and the rear lower arm. The outward extension intersection, that is, the lower set point of the virtual kingpin axis, is located in a relatively forward position as compared with the case where the inner end portion in the vehicle width direction of the rear lower arm is swung rearward with respect to the vehicle body. The reduction amount of the minute caster trail is reduced, and the return of the steering wheel is prevented from being deteriorated. Also, since the setting of the rear lower arm side including the sub-link is only devised, and it does not affect the front lower arm side, it is also preferable in terms of the degree of freedom in setting the lower arm as a whole. .

By using the slide bush as in claim 2, the structure of the connecting portion between the vehicle body and the rear lower arm can be simplified. Further, by using the assist link as in claim 3, the rear lower arm can be smoothly displaced rearward.

As described in claim 4, by connecting the suspension damper and the wheel supporting member with the upper arm, compared to a general strut suspension in which the suspension damper and the wheel supporting member are directly connected. The camber control of the wheels can be performed with a greater degree of freedom. Preferred embodiments of the invention and their advantages will be apparent from the description of the examples below.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings, as an example in the case of being applied to a front suspension of an FF vehicle. 1 to 4, 1 is a front lower arm, 2 is a rear lower arm, and 3 is a suspension damper.

The front lower arm 1 extends substantially parallel to the vehicle width direction, and its inner end portion in the vehicle width direction is rotatably attached to the vehicle body through a bush 4, and the axis of rotation thereof is approximately the front and rear of the vehicle body. It is aligned with the direction. An outer end portion of the front lower arm 1 in the vehicle width direction is attached to a lower end portion of a knuckle 6 as a wheel supporting member via a ball joint 5.

The lower end of the suspension damper 3 is connected to an intermediate portion of the front lower arm 1 via a mounting member 7. This mounting member 7 is used for the suspension damper 3
Has a tubular portion 7a that fits around the outer periphery of the lower end portion, and a pair of leg portions 7b that are bifurcated in the front-back direction from the lower end portion of the tubular portion 7a. The pair of legs 7b forming a fork shape are connected to the front lower arm 1 via a bush 8 with the front lower arm 1 sandwiched in the front-rear direction. As will be described later, the bush 8 is set so that the suspension damper 3 can rotate with respect to the front lower arm 1 about the vehicle longitudinal direction axis and can slightly slide in the vehicle longitudinal direction. Has been done. The pair of legs 7
A drive shaft (not shown) penetrates between b.

The rear lower arm 2 is set so as to have a substantially L shape as shown in FIG. An inner end portion of the rear lower arm 2 in the vehicle width direction extends substantially parallel to the vehicle body front-rear direction and is connected to the vehicle body via a slide bush 10 described later. Further, from the vicinity of the middle of the rear lower arm 2, a slight inclination is set so as to gradually move forward toward the outer side in the vehicle width direction, and the outer end in the vehicle width direction forms the ball joint 11. The ball joint 11 is connected to the lower end of the knuckle 6 via the knuckle 6, and the position of the ball joint 11 is located right after the ball joint 5 for the front lower arm 1.

The mounting member 7, that is, the suspension damper 3 and the upper end portion of the knuckle 6 are connected to each other via an upper arm 21. The upper arm 21 has a substantially U-shape that opens toward the inner side of the vehicle body and holds the tubular portion 7a of the mounting member 7 in the front-back direction.
It is connected to the mounting member 7 so as to be swingable in the vertical direction, that is, rotatable about an axis extending substantially in the front-rear direction of the vehicle body. An outer end portion of the upper arm 21 in the vehicle width direction is connected to an upper end portion of the knuckle 6 via a ball joint 23. Such an upper arm 21 is
The length in the vehicle width direction is set to be sufficiently shorter than the lower arms 1 and 2.

As shown in FIG. 2, the line connecting the center of the bush 4 for the front lower arm 1 and the center of the ball joint 5 is L1, and the center of the bush 10 of the rear lower arm 2 is the same. The line connecting the center of the ball joint 11 is L2. The lines L1 and L2 are connected to the ball joints 5 and 1, respectively.
They intersect on the outer side in the vehicle width direction than 1, and the intersection is indicated by KD.

A line connecting the intersection KD and the center KU of the ball joint 23 for the upper arm 21 constitutes a virtual kingpin axis KP (see FIG. 3). That is,
The center of the lu-joint 23 constitutes the upper set point of the virtual kingpin axis KP, and the intersection KD constitutes the lower set point of the virtual kingpin axis.

The intermediate portion of the rear lower arm 2 and the vehicle body are further connected via a sublink 25. That is, one end of the sub-link 25 is connected to the vehicle body via the ball joint 26. The other end of the sub-link 25 is connected to an intermediate part of the rear lower arm 2 via a ball joint 27. The ball joint 26 on the vehicle body side
Between the bushes 4 and 10, it is located in the immediate vicinity of the bush 4 and is set at substantially the same height as the bushes 4 and 10, so that the sub link 25 extends in a substantially horizontal direction. Then, the sub-link 25 is inclined so as to be located rearward as it goes outward in the vehicle width direction.

The sub-link 25 pushes the inner end of the rear lower arm 2 in the vehicle width direction toward the rear when the ball joint 11 for the rear lower arm 2 is displaced rearward. The force is transmitted as a force, and the ball joints 26, 2 are arranged so that such force transmission is effectively performed.
The connection positions for 7 and 2 have been selected. That is,
At the time of steering, the lower arms 1 and 2 for the wheels serving as turning outer wheels tend to swing rearward about the inner end side in the vehicle width direction, but the rear lower arm 2 has a ball. As a result of the distance between the joints 26 and 27 being regulated by the sub-link 25, the rear lower arm 2 is displaced rearward on the vehicle width direction outer end side and is also displaced rearward on the vehicle width direction inner end side. Will be done.

The above-mentioned bush 8 is constructed as shown in FIG. The bush 8 includes an outer cylinder 31 fitted in the mounting hole 1a of the front lower arm 1, an inner cylinder 32 into which a shaft to which the leg portion 7b is mounted is inserted, and both cylinders 31 and 32. The elastic material 33 such as rubber is filled in the gap.

A projection 34 extending in the axial direction is formed on the inner peripheral surface of the outer cylinder 31, and the projection 34 has an axial stroke.
The end portion is an inclined surface 34a that gradually decreases toward the end portion in the axial direction. Further, a concave portion 35 extending in the axial direction is formed on the outer peripheral surface of the inner cylinder 32.
The axial stroke end portion of is an arcuate surface 35a facing the inclined surface 34a. Such a protrusion 34
In the embodiment, the recess 35 and the recess 35 are formed over the entire length of the bush 8 in the circumferential direction.

The bush 8 having the above-mentioned structure is used for the outer cylinder 3
1 and the inner cylinder 32 are relatively displaced in the axial direction within a range of the axial distance between the inclined surface 34a and the arcuate surface 35a, which are set to be relatively large and are allowed to relatively rotate about the axis. I'm supposed to get it.

The bush 10 is constructed as shown in FIG. The bush 10 includes an outer cylinder 41, a middle cylinder 42, a longest inner cylinder 43, and an outer cylinder 41.
And an elastic member 44 such as rubber interposed between the inner cylinder 42 and the inner cylinder 42.

The clearance between the middle cylinder 42 and the inner cylinder 43 is made slightly larger so that they can rotate relative to each other around the axis, and they can relatively displace in the axial direction, that is, the front-rear direction of the vehicle body. There is. Then, with the inner end of the rear lower arm 2 in the vehicle width direction being inserted into the inner cylinder 43,
The inner cylinder 43 and the rear lower arm 2 are fixed using a nut 45. That is, while the flange portion 2a formed on the rear lower arm 2 is seated on one end surface of the inner cylinder 43, the washer is attached to the rear lower arm 2 protruding from the other end surface of the inner cylinder 43 in this state. After fitting 46, the nut 45 is screwed and the flange portion 2a and the washer 4 are
6 and the inner cylinder 43 is fixed in a state of being sandwiched from the axial direction. In order to smoothly perform the relative displacement between the middle cylinder 42 and the inner cylinder 43, a member having a low coefficient of friction, for example, a Teflon material, is interposed between the middle cylinder 42 and the inner cylinder 43 (a coating process is also possible). You can also

The operation of the present invention configured as described above will be described with reference to FIGS. 7 and 8. In the following description, reference symbol W is a wheel and O is a center of rotation of the wheel. First,
In FIG. 7, when the wheel W is viewed from the outside of the vehicle body, the virtual kingpin axis KP is tilted so as to be positioned forward as it goes downward, and the caster trail when the wheel is in a straight traveling state is indicated by T1. Be done. Now, assuming that the lower set point KD is displaced rearward while the upper set point KU of the virtual kingpin axis KP is not displaced, the caster trail becomes smaller as indicated by T2, and the steering wheel returns when turning. Become.

In FIG. 8, the state of the wheel W1 and the lower arms 1 and 2 when the wheel W is in a straight traveling state is shown by a solid line, and the lower set point of the virtual kingpin axis KP is KD.
Indicated by. In addition, in order to facilitate understanding, FIG.
The illustration is exaggerated.

The broken line shows the state of the wheel W which is the outer wheel when turning from the straight traveling state. During this steering, the wheel W is steered about the kingpin axis KP in the straight traveling state, while the steering position of the lower arms 1 and 2 with respect to the knuckle 6, that is, the wheel, is caused by the steering of the wheel W. -Le joints 5, 11 move backwards.

When the ball joints 5 and 11 move rearward, the states of the lower arms 1 and 2 when the lower arms 1 and 2 swing rearward around the vehicle body side connecting portion are described. It is shown by a broken line in the figure, and the lower set point of the virtual kingpin axis at this time is KD1, which is B than the original lower set point KD.
The caster trail will be considerably smaller after it has been displaced backwards by one minute. Each lower arm 1 and 2 which becomes this KD1
The displacement state of is conventional.

On the other hand, in the case of the present invention in which the sub-link 25 is provided and the inner end portion of the rear lower arm 2 in the vehicle width direction can be displaced in the vehicle front-rear direction, turning during steering is performed. The rear lower arm 2 for the wheel W on the outer wheel side is as shown by the alternate long and short dash line in the figure. That is, the inner end portion in the vehicle width direction of the rear lower arm 2 is displaced rearward. The lower set point of the virtual kingpin axis at this time is KD2, and although it is displaced backward by B2 from the original lower set point KD, it is smaller than the displacement B1 (B1> B2). That is, in the present invention, the reduction amount of the caster trail is suppressed to a small amount, and the deterioration of the return of the steering wheel when turning is suppressed.

FIG. 9 shows another embodiment of the present invention.
The same components as those of the above-described embodiment are designated by the same reference numerals, and the duplicated description will be omitted. This FIG. 9 corresponds to FIG. 2 and is shown as a skeleton diagram for simplification.

This embodiment is different from the above-mentioned embodiment only in the mounting structure of the rear lower arm 2 on the vehicle body side. That is, an assist link 51 extending substantially in the vehicle width direction is separately provided, and an inner end portion of the assist link 51 in the vehicle width direction is connected to the vehicle body via a bush 52 so as to be swingable in the front-rear direction. The inner end of the rear lower arm 2 in the vehicle width direction and the outer end of the assist link 51 in the vehicle width direction are connected to each other by the joint 5
3 is rotatably connected about an axis extending substantially vertically.

In the embodiment shown in FIG. 9, when the steering wheel is steered, the assist link 51 for the wheel on the turning outer wheel side swings rearward, so that the inner end of the rear lower arm 2 in the vehicle width direction. The portion is displaced rearward to prevent the lower set point of the virtual kingpin axis from being displaced rearward.

Although the embodiment has been described above, the suspension damper 3 and the knuckle 6 may be directly connected to each other without the upper arm 21. Also,
The same can be applied to a rear wheel suspension, particularly for a so-called 4WS vehicle in which rear wheel steering is performed. Furthermore, in the embodiment, a so-called negative camber having a negative scrub radius is shown, but the present invention is also applicable to a zero scrub or positive camber. Of course, it can be applied not only for the drive wheels but also as a suspension for the driven wheels.

[Brief description of drawings]

FIG. 1 is an overall perspective view showing an embodiment of the present invention.

FIG. 2 is a plan view showing front and rear lower arm portions.

FIG. 3 is a rear view of the lower arm portion as viewed from the rear.

FIG. 4 is a side view of front and rear lower arms as viewed from the inside of the vehicle body.

FIG. 5 is a cross-sectional view showing an example of a bush used in a connecting portion between a suspension damper and a front lower arm.

FIG. 6 is a cross-sectional view showing an example of a slide bush used at a connecting portion between a rear lower arm and a vehicle body.

FIG. 7 is an explanatory view for explaining the influence of the rearward displacement of the lower set point of the virtual kingpin axis on the change of the caster trail.

FIG. 8 is an explanatory view for explaining the operation of the present invention while comparing it with a conventional one.

FIG. 9 shows another embodiment of the present invention.
Skeleton diagram corresponding to.

[Explanation of symbols]

 1: Front lower arm 2: Rear lower arm 3: Suspension damper 6: Knuckle (wheel support member) 7: Mounting member 10: Slide bush 21: Upper arm 25: Sublink 51: Assist link KP: Virtual kingpin shaft KU: Upper set point KD: Lower set point KD1: Lower set point during steering (conventional) KD2: Lower set point during steering (present invention)

Claims (4)

[Claims] 1. A wheel support member for steered wheels is supported by a vehicle body through a front lower arm and a rear lower arm so as to be vertically swingable, and the front lower arm and the rear lower arm are supported. In a vehicle suspension device in which a virtual kingpin axis lower set point is constituted by an intersection point extending outward from the vehicle body, an inner end portion of the rear lower arm in the vehicle width direction is slidable in a vehicle body front-rear direction. And connecting the intermediate portion of the rear lower arm and the vehicle body, and inward of the rear lower arm in the vehicle width direction in accordance with the rearward displacement of the outer end portion of the rear lower arm in the vehicle width direction. A suspension device for a vehicle, characterized in that a sub-link for pressing the end portion rearward is provided. 2. The vehicle body according to claim 1, wherein an inner end portion of the rear lower arm in the vehicle width direction is slidably connected to a vehicle body in the front-rear direction via a sliding bush. 3. A wheel supporting member comprising a front lower arm and a rear lower arm.
A vehicle which is swingably supported in the vertical direction by a vehicle body and which constitutes a lower set point of the virtual kingpin axis by an extension intersection of the front lower arm and the rear lower arm on the outer side of the vehicle body. In the suspension device described above, an inner end portion in the vehicle width direction of the rear lower arm is coupled to an outer end portion in the vehicle width direction of an assist link attached to the vehicle body so as to be swingable in the vehicle body front-rear direction, and the rear lower arm is provided. For connecting the middle part of the vehicle body and the vehicle body to press the rear inner end of the rear lower arm in the vehicle width direction rearward in accordance with the rearward displacement of the outer end of the rear lower arm in the vehicle width direction. A vehicle suspension device characterized in that a sub-link is provided. 4. The suspension damper according to claim 1, wherein a lower end portion of the suspension damper is connected to the front lower arm, and the suspension damper and the wheel support member are interposed by an upper arm. Those that are connected.