JP3078912B2 - Vehicle suspension device - Google Patents

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 support member for a steered wheel, that is, a knuckle is supported by a vehicle body via at least a lower arm so as to be vertically swingable. The wheels attached to the wheel support members are required to be set to have a predetermined wheel alignment. One important factor that determines the wheel alignment is a kingpin shaft.

[0003] That is, when viewed from the front (rear) of the vehicle body, the downward extension of the kingpin shaft is located slightly outside the vehicle body in the width direction center line of the vehicle. In. Further, the kingpin axis is located slightly inward of the vehicle body than the center line in the width direction of the wheel at the rotational center height position of the wheel so that the wheel is toned when receiving driving force. It is desired 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 slightly inclined so as to be positioned outwardly of the vehicle body as it goes downward when viewed from the front of the vehicle body. For example, in a strut type suspension, the connection between the lower arm and the wheel support member constitutes a lower set point, and the connection between the suspension damper and the wheel support member constitutes an upper set point. The line connecting the points is the kingpin axis.

In order to satisfy the above-mentioned requirement for the inclination of the kingpin shaft, the lower set point, that is, the outer end of the lower arm in the vehicle width direction is greatly extended deeper into the inner diameter portion of the wheel, that is, outwardly in the vehicle width direction. However, from the viewpoint of preventing interference with brake discs and the like,
It is practically difficult to greatly extend the vehicle outward in the vehicle width direction in the circumferential direction.

The lower arm is divided into two parts, a front lower arm and a rear lower arm, so that the lower set point of the kingpin shaft is located more outwardly in the vehicle width direction, and a wheel support member and a lower arm are provided. There has been proposed a so-called double pivot type suspension in which the number of connection portions with the system is two (see Japanese Patent Publication No. 58-42042). That is, the lower set point of the virtual kingpin axis is intended to be constituted by the intersection of the front lower arm and the rear lower arm extending outwardly from the vehicle body. More specifically, a line connecting the vehicle side connecting portion of the front lower arm and the wheel supporting member side connecting portion, and a line connecting the vehicle body side connecting portion of the rear lower arm and the wheel supporting member side connecting portion. By locating the intersection on the outer end side in the vehicle width direction with respect to the connecting portion of each lower arm to the wheel support member, the intersection is configured as a substantially lower set point of the virtual kingpin axis. is there.

[0007]

However, in the case where the lower arm is formed as a virtual kingpin axis as a divided structure of a front lower arm and a rear lower arm, when the steering is turned, It has been found that the caster trail of the wheel on the side serving as the turning outer wheel becomes small, causing a problem that the return of the steering wheel becomes poor.

To explain this point in detail, when turning with the steering wheel turned, the outer wheel is steered about the virtual kingpin axis in the straight running state as the instantaneous center. When this steered,
The connecting portions of the front lower arm and the rear lower arm to the wheel supporting members are relatively displaced rearward as compared with the straight traveling state, whereby each lower arm swings toward the rear of the vehicle body. Movement, the lower set point of the virtual kingpin axis is displaced rearward, which results in a smaller caster trail and a poor return of the handle. In particular, since the turning outer wheel is a wheel that substantially controls the return of the steering wheel due to the load movement of the vehicle body, the steering wheel returns when driving at a high speed and a large steering angle such as during sports running. The deterioration was considerable, and in extreme cases the wheels could be steered more than intended.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and in a case where a lower set point of a virtual kingpin axis is constituted by a front lower arm and a rear lower arm, a return of a handle is provided. An object of the present invention is to provide a vehicle suspension device capable of reducing deterioration.

[0010]

In order to achieve the above object, the present invention has the following configuration. That is, a wheel supporting member for steered wheels is vertically swingably supported by a vehicle body via a front lower arm and a rear lower arm, and the vehicle body of the front lower arm and the rear lower arm is provided. In a vehicle suspension apparatus wherein a lower set point of a virtual kingpin axis is constituted by an outer extension intersection, the front lower
The rear lower arm is connected to the vehicle body in such a manner that the inner end in the vehicle width direction of the vehicle is displaceable in the front-rear direction, and the rear lower arm is connected to the vehicle body in the vehicle width direction via a sub-link mounted to be swingable in a substantially horizontal direction. The front and rear lower arms are interlocked so that the front end of the front lower arm is displaced rearward when swung rearward around the inner end. is there.

In order to make the inner end of the front lower arm in the vehicle width direction displaceable in the front-rear direction, a sub-link is used, that is, the inner end of the front lower arm in the vehicle width direction with respect to the sub-link is used. It can be obtained by mounting via a ball joint. Further, the inner end in the vehicle width direction of the front lower arm can be displaced in the front-rear direction by using the slide bush without using the sub-link.

In the suspension device according to the present invention, the suspension damper and the wheel support member can be connected via the upper arm without directly connecting the suspension damper and the wheel support member. The lower end of the suspension damper can be connected to a lower arm, for example, a front lower arm.

[0013]

According to the present invention, as a result of the rear end of the steered front lower arm for the turning outer wheel being largely displaced rearward in the vehicle width direction, the vehicle body having the front lower arm and the rear lower arm is displaced. The outer extension intersection, i.e., the lower set point of the virtual kingpin axis, is located relatively forward as compared with the conventional case in which the inner end of the front lower arm in the vehicle width direction cannot be displaced substantially backward. Reduction of the minute caster trail is suppressed, and deterioration of the return of the steering wheel is prevented.

According to a fourth aspect of the present invention, the suspension damper and the wheel support member are connected by the upper arm, so that the suspension damper and the wheel support member are directly connected to each other. The camber control of the wheels can be performed with a greater degree of freedom. Preferred aspects of the invention and its advantages will be apparent from the description of the following examples.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings, in which an embodiment is applied to a front suspension of a front-wheel-drive vehicle. 1 to 4, reference numeral 1 denotes a front lower arm, 2 denotes a rear lower arm, and 3 denotes a suspension damper.

The front lower arm 1 extends substantially parallel to the vehicle width direction, and its inner end in the vehicle width direction is attached to the vehicle body via a sub-link 15 extending substantially horizontally. The sub-link 15 is attached to the vehicle body via a bush 16 so as to be swingable in a substantially horizontal direction. The front lower arm 1 is connected to a middle portion of such a sub-link via a ball joint 17.
(See also FIG. 5).

The swing center of the sub-link 15 is located forward of the front lower arm 1 and is inclined so as to be gradually located outward in the vehicle width direction toward the rear. When the sub-link 15 is rotated clockwise from the state shown in FIG. 2, the inner end of the front lower arm 1 in the vehicle width direction is displaced rearward. Also, the outer end of the front lower arm 1 in the vehicle width direction is
It is attached to the lower end of a knuckle 6 as a wheel support member via a ball joint 5.

A lower end of the suspension damper 3 is connected to an intermediate portion of the front lower arm 1 via a mounting member 7. The mounting member 7 is used for the suspension damper 3.
And a pair of legs 7b that are bifurcated in the front-rear direction from the lower end of the cylindrical portion 7a. A pair of legs 7b forming a fork shape is connected to the front lower arm 1 via a bush 8 with the front lower arm 1 sandwiched in the front-rear direction. As described later, the bush 8 is set so that the suspension damper 3 can rotate about the longitudinal axis of the vehicle body with respect to the front lower arm 1 and can slide slightly in the longitudinal direction of the vehicle body. Have been. In addition, a pair of legs 7
A drive shaft (not shown) is penetrated between b.

The rear lower arm 2 is set so as to be substantially L-shaped as shown in FIG. Thereafter, the inner end in the vehicle width direction of the lower arm 2 extends substantially parallel to the vehicle longitudinal direction, and is connected to the vehicle body via a bush 10 so as to be vertically swingable. Further, the rear lower arm 2 is set to be slightly inclined so as to gradually move forward from near the middle toward the outside in the vehicle width direction, and the outer end in the vehicle width direction is formed with the ball joint 11. The ball joint 11 is connected to the lower end of the knuckle 6 via the ball joint 11, of course, and is located immediately behind the ball joint 5 for the front lower arm 1.

The mounting member 7, ie, the suspension damper 3, and the upper end of the knuckle 6 are connected via an upper arm 21. The upper arm 21 is formed in a substantially U-shape opened toward the inside of the vehicle body, and the bush 2 is held in a state where the tubular portion 7a of the mounting member 7 is sandwiched from the front-rear direction.
2 is connected to the mounting member 7 so as to be swingable up and down, that is, rotatable about an axis extending substantially in the longitudinal direction of the vehicle body. The outer end of the upper arm 21 in the vehicle width direction is connected to the upper end 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, a line connecting the center of the ball joint 17 for the front lower arm 1 and the center of the ball joint 5 is denoted by L1, and the bush 10 of the rear lower arm 2 is denoted by L1. A line connecting the center of the ball joint 11 and the center of the ball joint 11 is denoted by L2. These lines L1 and L2 intersect outside the ball joints 5 and 11 in the vehicle width direction, 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 joint 23 forms the upper set point of the virtual kingpin axis KP, and the intersection KD forms the lower set point of the virtual kingpin axis.

The middle part of the rear lower arm 2 and the sub-link 15
Is connected via a connection link 25. That is, one end of the connection link 25 is connected to the sub-link 15 via the ball joint 26. The other end of the connection link 25 is connected to an intermediate portion of the rear lower arm 2 via a ball joint 27. Link 2
5 extends in a substantially horizontal direction and is slightly inclined so as to gradually move outward in the vehicle width direction toward the rear.

The connecting link 25 transmits the movement when the rear lower arm 2 swings rearward about the bush 10 so that the sub-link 15 rotates clockwise in FIG. That is, it is for displacing the inner end of the front lower arm 1 in the vehicle width direction rearward, and the fulcrums 16 and 1 are arranged so that such a force can be effectively transmitted.
The positions of 7, 26 and 27, the lengths and inclinations of the links 15 and 25 are set.

The above-described bush 8 is configured as shown in FIG. The bush 8 includes an outer cylinder 31 fitted into the mounting hole 1a of the front lower arm 1, an inner cylinder 32 into which a shaft to which the leg 7b is attached is inserted, and a space between the two cylinders 31 and 32. And an elastic material 33 such as rubber filled in the gap.

A projection 34 extending in the axial direction is formed on the inner peripheral surface of the outer cylinder 31.
The cut end is an inclined surface 34a that becomes gradually lower toward the end in the axial direction. A recess 35 extending in the axial direction is formed on the outer peripheral surface of the inner cylinder 32.
Is formed as an arcuate surface 35a facing the inclined surface 34a. Such a protrusion 34
The recess 35 is formed over the entire length of the bush 8 in the circumferential direction in the embodiment.

The bush 8 having the above-described structure is used to
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 is allowed to rotate slightly around the axis and is set relatively large. I am getting it.

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 indicates a wheel, and O indicates the 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 set to be inclined so as to be located forward as it goes downward, and the caster trail when the wheel is in a straight running state is indicated by T1. It is. Now, assuming that the lower set point KD is displaced rearward without the upper set point KU of the virtual kingpin axis KP being displaced, the caster trail becomes smaller as indicated by T2, and the steering wheel is not easily returned when steered. Become.

In FIG. 8, the state of the wheel W1 and each of 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 FIG. 8 shows, for easy understanding,
It is exaggerated.

The state of the wheel W which is the turning outer wheel when the vehicle is steered from the straight traveling state is shown by a broken line. During this steering, the wheel W is steered about the kingpin axis KP which is in a straight running state, while the lower arm 1, 2 is connected to the knuckle 6 due to the steering of the wheel W, that is, the bob. -The joints 5, 11 move rearward.

The state of the lower arms 1 and 2 when the lower arms 1 and 2 swing rearward around the vehicle-body-side connecting portion when the ball joints 5 and 11 move rearward. The lower set point of the virtual kingpin axis is KD1 at this time, which is smaller than the original lower set point KD by B.
Displaced rearward by one minute, the caster trail becomes considerably smaller. Each lower arm 1 and 2 which becomes this KD1
Is a conventional displacement state.

On the other hand, in the case of the present invention, the front lower arm 1 for the wheel W on the turning outer wheel side at the time of turning is used.
Is indicated by a dashed line in the figure. That is, the inner end in the vehicle width direction of the front lower arm 1 is displaced rearward. At this time, the lower set point of the virtual kingpin axis is KD2, and is displaced backward by B2 from the original lower set point KD,
It becomes smaller than the displacement B1 (B1> B2). In other words, according to the present invention, the caster trail is reduced to a small amount, and 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 denoted by the same reference numerals, and the description thereof will not be repeated. FIG. 9 corresponds to FIG. 2 and is shown as a skeleton diagram for simplicity.

In this embodiment, the inner end of the front lower arm 1 in the vehicle width direction is slidable in the front-rear direction via a slide bush 51 and attached to the vehicle body, while the inner end of the rear lower arm 2 in the vehicle width direction. The part is attached to the vehicle body via a sub-link 52 (corresponding to the sub-link 15 in the above embodiment). That is, the sub-link 52 is attached to the vehicle body at a substantially intermediate position via a bush 53 so as to be swingable in a substantially horizontal direction, and a ball joint 54 is attached to the outer end of the sub-link 52 in the vehicle width direction. Through lower arm 2
Is mounted at the inner end in the vehicle width direction.

The inner end of the sub link 52 in the vehicle width direction and the vicinity of the bush 51 of the front lower arm 1 are connected to the connecting link 5.
5 (corresponding to the connection link 25 of the above embodiment). Reference numerals 56 and 57 denote ball joints for connecting the link.

In this embodiment, when the outer end in the vehicle width direction of the rear lower arm 2 used for the turning outer wheel is about to be displaced rearward, the length of the rear lower arm 2 is invariable, so that the sub link 52 is not changed. It turns counterclockwise in FIG.
The inner end of the vehicle 1 in the vehicle width direction is pulled rearward via the connection link 55.

In this embodiment, as in the previous embodiment, the lower set point KD of the virtual kingpin axis KP is displaced rearward, and the deterioration of the return of the steering wheel is suppressed. The inner end of the rear lower arm 2 in the vehicle width direction is slightly displaced forward to reduce the caster trail. However, the rear end of the front lower arm 1 is largely displaced rearward by the inner end in the vehicle width direction. The amount of reduction of the caster trail is sufficiently suppressed.

The bush 51 is configured as shown in FIG. The bush 51 includes an outer cylinder 41,
The middle cylinder 42, the longest inner cylinder 43, and the outer cylinder 4
An elastic member 44 such as rubber is interposed between the first and middle cylinders 42. The inner end of the front lower arm 1 in the vehicle width direction is fitted and integrated with the outer cylinder 41.

The gap between the middle cylinder 42 and the inner cylinder 43 is slightly increased so that they can relatively rotate around the axis with each other, and can be relatively largely displaced in the axial direction, that is, in the longitudinal direction of the vehicle body. I have. Then, in a state where the mounting shaft 47 fixed to the vehicle body is inserted into the inner cylinder 43,
The inner cylinder 43 and the mounting shaft 47 are fixed using a nut 45. That is, while the flange portion 47a formed on the mounting shaft 47 is seated on one end surface of the inner cylinder 43, the mounting shaft 4 projecting from the other end surface of the inner cylinder 43 in this state.
After the washer 46 is fitted to the nut 7, the nut 45 is screwed into the nut 7, and the inner cylinder 43 is fixed between the flange portion 47 a and the washer 46 in the axial direction. In order to make the relative displacement between the middle cylinder 42 and the inner cylinder 43 smooth, a member having a low coefficient of friction, for example, a Teflon material is interposed between the two cylinders 42 and 43 (a coating process is also possible). You can also.

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

[Brief description of the drawings]

FIG. 1 is an overall perspective view showing one 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 viewed from the rear.

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

FIG. 5 is an enlarged view showing details of a sub-link portion to which a vehicle width direction inner end portion of a front lower arm is attached.

FIG. 6 is a sectional view showing an example of a bush used for a connection portion between a suspension damper and a front lower arm.

FIG. 7 is an explanatory diagram for explaining an effect of a rearward displacement of a lower set point of the virtual kingpin axis on a change in caster trail.

FIG. 8 is an explanatory view for explaining the operation of the present invention in comparison with a conventional one.

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

FIG. 10 is a sectional view showing an example of the slide bush used in FIG. 9;

[Explanation of symbols]

 1: Front lower arm 2: Rear lower arm 3: Suspension damper 6: Knuckle (wheel support member) 7: Mounting member 15: Sub-link 16: Bush 17: Ball joint 21: Upper arm 25: Connection link 26: Ball joint 27: Ball joint 51: Slide bush 52: Sub link 53: Bush 54: Ball joint 55 Connection link 56: Ball joint 57: Ball joint KP: Virtual kingpin axis KU : Upper set point KD: Lower set point KD1: Lower set point during turning (conventional) KD2: Lower set point during turning (present invention)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-92711 (JP, A) JP-A-3-10919 (JP, A) JP-A-3-231011 (JP, A) 182822 (JP, A) JP-A-2-220904 (JP, A) JP-A-63-106118 (JP, A) JP-A-61-218408 (JP, A) JP-A-2-75378 (JP, U) Shokai 61-17311 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60G 3/18

Claims (4)

(57) [Claims] A wheel supporting member for a steered wheel is vertically swingably supported on a vehicle body via a front lower arm and a rear lower arm, and the front lower arm and the rear lower arm are provided. A lower set point of the virtual kingpin axis formed by the intersection of the vehicle outer side extension with the vehicle body, wherein the inner end in the vehicle width direction of the front lower arm is connected to the vehicle body so as to be displaceable in the front-rear direction. When the rear lower arm is pivoted rearward about a vehicle width direction inner end portion through a sub-link attached to the vehicle body so as to be pivotable substantially horizontally, the front lower arm The front and rear lower arms are interlocked so that the inner end of the vehicle in the vehicle width direction is displaced rearward. 2. The vehicle according to claim 1, wherein an inner end in the vehicle width direction of the front lower arm is attached to the sub-link via a ball joint, and an intermediate portion of the rear lower arm connects a connecting link. Attached to the sub-link via 3. The vehicle according to claim 1, wherein the front lower arm has an inner end in the vehicle width direction attached to a vehicle body via a slide bush, and the rear lower arm has a ball joint in an inner end in the vehicle width direction. And an intermediate portion of the front lower arm is attached to the sub-link via a connecting link. 4. The suspension damper according to claim 1, wherein a lower end of the suspension damper is connected to the front lower arm, and the suspension damper and the wheel support member are connected via an upper arm. What is connected.