JPH0789312A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To reduce an increase in a positive directional camber change at bound time even if an elastic body is adopted as a link member. CONSTITUTION:Wheels 1 are supported rotatably freely with knuckle spindles 2. Lower arms 5 are connected to the lower parts of the knuckle spindles 2. The lower arms extend in the car body width direction, and the other end parts are connected to the car body side. The lower arms 5 are composed of a plate-like elastic body, and the car body side installing parts are joined rigidly to a car body. In the lower arms 5, plural notches 6 extending in the longitudinal direction of the car body are formed respectively in the car body width direction on an upper surface of the wheel side part 5a and an under surface of the car body side part 5b, so that rigidity changing means are arranged in both parts 5a and 5b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension system for a vehicle, and more particularly, to at least one of the connecting members for connecting a wheel supporting member for rotatably supporting a wheel and a vehicle body, for example, a lower arm is made of an elastic material. The present invention relates to a suspension system for a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a suspension system for a vehicle in which an elastic body is used as a connecting member, for example, an actual Kaihei 3-8680.
Some are disclosed in Japanese Patent No. The left and right wheels are rotatably supported by the left and right wheel support members, and shock absorbers and connecting members are attached to the wheel support members.

The shock absorber has its lower end fixed to the upper portion of the wheel support member and extends upward, and its upper end is attached to the vehicle body. The connecting member is composed of a lower arm for lateral positioning and a trailing arm for longitudinal positioning. The trailing arm has one end connected to a vehicle front-rear direction front portion under the wheel support member and extends forward in the vehicle front-rear direction, and the other end is connected to the vehicle body side.

The lower arm is a plate-shaped member made of an elastic body which is elastically deformable in the vertical direction and is formed by integrally molding two lower links extending in the vehicle width direction.
The two foot parts located on the wheel side are connected to the lower part of the wheel support member so as to be swingable in the vertical direction, and the base part on the vehicle body side is rigidly connected to the vehicle body in a vertically non-rotatable manner. It is set up.

Therefore, the weight can be reduced, and the suspension spring is not required, so that the layout is improved.

[0006]

In the conventional suspension system for a vehicle as described above, since the lower arm is composed of a plate-shaped elastic body and the vehicle body side mounting portion is mounted by a rigid connection, It is in a state similar to that of a cantilever having a vehicle body side attachment portion as a fulcrum, and is vertically bent by a vertical load applied to the wheel side attachment portion with the vehicle body side as a fulcrum.

Therefore, when the elastic body is deformed in the vertical direction with respect to the vehicle body due to the vertical load applied to the wheel side attachment portion due to the bound and rebound of the wheel, the entire lower arm bends in the displacement direction, The span between the wheel-side attachment point and the vehicle-body-side attachment point is displaced inward in the vehicle body width direction as compared with the case where the lower arm is made of a rigid body.

This is because the lower part of the wheel supporting member, that is, the lower part of the wheel, increases the relative displacement inward in the vehicle width direction at the time of bounce / rebound, so that the camber change of the wheel at the time of bounce is positive. Will be increased. However, when the vehicle turns, the roll of the vehicle body normally inputs a camber change in the positive direction to the outer wheels.Therefore, in order to make the ground camber angle close to zero, the camber change in the positive direction can be changed by the suspension stroke. I would like to cancel, but in the above-mentioned conventional vehicle suspension system, compared with the case where the lower arm is made of a rigid body as described above, the camber change in the positive direction due to the suspension stroke is increased, and the turning performance of the vehicle is deteriorated. There's a problem.

The present invention has been made by paying attention to the above problems. Even if an elastic body is adopted as the connecting member, the increase in the change in the camber in the positive direction at the time of bouncing is reduced, and the increase occurs. The purpose is to solve various problems.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and connects a wheel supporting member for rotatably supporting a wheel to a vehicle body side member to form a vehicle body side end. A suspension device for a vehicle, comprising a resilient connecting member whose portion is attached to a body-side member so as not to be rotatable in the vertical direction with respect to the vehicle body, and elastically deformable in the vertical direction with respect to the vehicle body. In at least one of the vehicle body side portion and the wheel side portion of the vehicle, rigidity changing means is provided, and the rigidity changing means increases the bending rigidity of the elastic coupling member upward or downward when the wheel is bound or rebounded. It is characterized by changing high or low with respect to.

The rigidity changing means may have, for example, a notch extending on at least one of the vehicle body side portion and the wheel side portion of the elastic connecting member on the upper surface side or the lower surface side, the notch extending substantially orthogonal to the axial direction of the elastic connecting member. It is characterized in that it is formed along the axial direction of the elastic connecting member. Alternatively, the rigidity changing means may be configured such that a fiber member having flexibility in the vertical direction and having a predetermined hardness in the axial direction is provided on the upper surface side or the lower surface side of the elastic connecting member along the axial direction of the elastic connecting member. It is characterized by being fixed by.

[0012]

In the elastic connecting member, a bending moment in the vertical direction is input by the bouncing and rebounding of the wheels, and the elastic connecting member bends vertically with the vehicle body mounting portion as a fulcrum. For example, when the rigidity distribution means is provided in the wheel side portion of the elastic coupling member so that the downward bending rigidity of that portion is set to be lower than that of the vehicle body side portion, the wheel rebounds, that is, the wheel side. When a downward load is input to the mounting portion, the bending rigidity of the wheel side portion, which is the position where the rigidity changing means is provided, is low in the axial direction of the elastic connecting member. Direction of the vehicle body side portion and the vehicle body side portion does not bend so much, as shown in J of FIG.
Compared to the case where the rigidity changing means is not provided (H), the wheel side mounting portion is displaced in the axial direction of the elastic coupling member in the direction approaching the vehicle body side mounting portion side.

In FIG. 14, H is the case of a conventional elastic connecting member without the rigidity changing means, and J is the bending state when the rigidity changing means is provided. Further, F indicates a vehicle body side mounting portion, and G indicates a wheel side mounting portion. Further, when the rigidity distribution means is provided in the vehicle body side portion of the elastic connecting member so that the downward bending rigidity of the portion is set to be lower than that of the wheel side portion, the wheel rebounds, that is, is attached to the wheel side. When a downward load is applied to the portion, the bending rigidity of the vehicle body side portion at the position where the rigidity changing means is provided is low in the axial direction of the elastic coupling member. Since the wheel side portion is bent more than the side portion and the wheel side portion is not bent so much, as shown in K of FIG. 14, in the axial direction of the elastic connecting member, as compared with the case where the rigidity changing means is not provided (H), The wheel side mounting portion is displaced in the direction away from the vehicle body side mounting portion side.

In FIG. 14, the alternate long and short dash line shows the case where the connecting member is made of a rigid body. Further, by providing the rigidity distribution means on the wheel side portion of the elastic connecting member,
When the downward bending rigidity of that portion is set higher than that of the vehicle body side portion, when the wheel rebounds, that is, when a downward load is input to the wheel side mounting portion, the rigidity is increased in the axial direction of the elastic connecting member. Since the downward bending rigidity of the wheel side portion at the position where the changing means is provided becomes higher, the vehicle body side portion is relatively configured to have a lower downward rigidity than the wheel side portion.
Mainly, the body side portion bends more than the axial wheel side portion and the wheel side portion does not bend so much. Therefore, rigidity changing means is provided in the body side portion to reduce the bending rigidity of the portion. In comparison with the case where the rigidity changing means is not provided, the wheel-side mounting portion is displaced in the axial direction of the elastic connecting member in the direction away from the vehicle-body-side mounting portion side, as compared with the case where the rigidity changing means is not provided.

Further, by providing rigidity distribution means in the vehicle body side portion of the elastic connecting member, when the downward bending rigidity of that portion is set higher than that of the wheel side portion, the wheel rebounds, that is, is mounted on the wheel side. When a downward load is applied to the portion, the bending rigidity of the elastic coupling member in the axial direction of the elastic coupling member becomes higher in the downward bending rigidity of the vehicle body side portion at the position where the rigidity changing means is provided.
Since the rigidity of the wheel side portion is relatively lower than that of the vehicle body side portion, the wheel side portion bends more largely than the vehicle body side portion in the axial direction, and the vehicle body side portion bends a little. Therefore, it has the same effect as providing rigidity changing means on the wheel side portion to reduce the downward bending rigidity of that portion, as compared with the case where the rigidity changing means is not provided,
In the axial direction of the elastic connecting member, the wheel side mounting portion is displaced in a direction approaching the vehicle body side mounting portion side.

Further, rigidity changing means is provided at a vehicle body side portion or a wheel side portion of the elastic connecting member to set the upward bending rigidity of the portion to be high or low so that the wheel bounces, that is, the wheel side mounting portion. Even when an upward load is input to, the same action as above occurs. That is, if the upward bending rigidity of the wheel side portion is set low by the rigidity changing means or the upward bending rigidity of the vehicle body side portion is set high,
At the time of bouncing, as compared with the case where the rigidity changing means is not provided, in the axial direction of the elastic connecting member, the wheel side mounting portion is displaced toward the vehicle body side mounting portion side.

Further, when the rigidity changing means is used to reduce the upward bending rigidity of the vehicle body side portion or the upward bending rigidity of the wheel side portion is set, the rigidity changing means is not provided with the rigidity changing means as compared with the case where the rigidity changing means is not provided. Then, in the axial direction of the elastic connecting member, the wheel side mounting portion is displaced in the direction away from the vehicle body side mounting portion side. Furthermore, by combining the above actions, for example, by lowering the upward bending rigidity of the wheel side portion by the rigidity changing means, and by setting the upward bending rigidity of the vehicle body side portion to a higher level, when bounding, Compared with the case where the rigidity changing means is not provided, the wheel-side mounting portion can be displaced in the axial direction of the elastic coupling member in the direction approaching the vehicle-body-side mounting portion side.

Further, the rigidity changing means lowers the upward bending rigidity of the vehicle body side portion and sets the upward bending rigidity of the wheel side portion so that the rigidity changing means is not provided at the time of further bounce. In comparison with the above case, the wheel-side mounting portion can be displaced in the axial direction of the elastic coupling member in the direction away from the vehicle-body-side mounting portion side. As the rigidity changing means, for example, the rigidity changing means described in claim 2 is used.

The rigidity changing means forms a notch on the upper surface side or the lower surface side of the elastic connecting member extending in a direction substantially orthogonal to the axial direction of the elastic connecting member along the axial direction of the elastic connecting member. carry out. For example, when the notch is provided on the upper surface side, when a downward load is input to the wheel side attachment portion of the elastic arm due to the rebound of the wheel, a downward bending moment is input to each portion.

As a result, the elastic connecting member is compressed on the lower surface side sandwiching the central axis thereof and pulled on the upper surface side,
Resisting it, compressive stress and tensile stress are generated respectively. However, since the elastic connecting member bends downward, the gap between the cuts provided on the upper surface side is opened, and the tensile stress in that portion is reduced, so the resistance to the upward bending moment is reduced and the bending rigidity is reduced. Becomes smaller.

On the other hand, when an upward load is applied to the wheel-side mounting portion of the elastic connecting member, an upward bending moment is input to each part, and the elastic connecting member is attached to the upper surface side across the central axis. It is compressed and the lower surface side is pulled, and tensile stress and compressive stress are generated by resisting each, but between the notches on the upper surface side, they are pressed against each other and the same compressive stress is generated as when the notches are not provided. Thus, the bending rigidity is equivalent to that when the rigidity changing means is not provided.

However, when the cut has a predetermined gap in the axial direction, since the compressive stress is low until the facing surfaces forming the cut come into contact with each other, the bending rigidity is set to be weak halfway. For this reason, both the upper and lower bending moments at the portion where the notch is provided are set low. Further, as the rigidity changing means, for example, the rigidity changing means described in claim 3 may be used.

The rigidity changing means comprises a fiber member having flexibility in the vertical direction and having a predetermined hardness in the axial direction on the upper surface side or the lower surface side of the elastic connecting member and in the axial direction of the elastic connecting member. It is carried out by fixing along. For example,
When it is installed on the upper surface side, by rebounding the wheels,
When a downward load is input to the wheel-side mounting portion of the elastic connecting member, a downward bending moment is input to each part.

As a result, the elastic connecting member is compressed on the lower surface side with respect to the central axis and pulled on the upper surface side,
Resisting it, compressive stress and tensile stress are generated respectively. At this time, the elastic connecting member bends downward, whereby a tensile force is input to the fiber member provided on the upper surface side, and the fiber member resists the tensile force. As a result, in that portion, the resistance to the bending moment on the upper surface side is increased and the bending rigidity is increased.

On the other hand, when an upward load is input to the wheel-side mounting portion of the elastic connecting member, an upward bending moment is input to each portion, and the elastic connecting member is moved upward on the upper side of the central axis. Compressed, the lower surface side is pulled, and tensile stress and compressive stress are generated respectively by resisting it, but the fiber member fixed on the upper surface side bends and does not resist the compressive force, so it is equivalent to the case without the fiber member. Has bending rigidity.

Incidentally, the rigidity changing means by the above notch,
Also, a rigid means using a fiber member may be used in combination. Also,
Since the rigidity changing means is an example, it may be implemented by using elastic members having different elastic forces in the upper and lower thickness directions.

[0027]

Embodiments of the present invention will be described with reference to the drawings.
In the first embodiment, a strut type vehicle suspension device will be described as an example. First, the structure will be described. As shown in FIG. 1, the left and right wheels 1, 1 are rotatably supported by the left and right knuckle spindles 2, 2 which are wheel supporting members. The lower parts of the shock absorbers 3, 3 constituting the above are gripped. The shock absorber 3 extends upward, and its tip is fixed to a vehicle body-side member (not shown).

Further, one end portions of trailing arms 4 and 4 are connected to the front lower portions of the wheel supporting members 2 and 2 in the front-rear direction of the vehicle body, respectively. Its trailing arm 4,
Reference numeral 4 extends forward in the front-rear direction of the vehicle body, and its tip is attached to the vehicle-body-side member via a bush. Further, one ends of the lower arms 5, 5 (elastic connecting members) are connected to the lower portions of the wheel supporting members 2, 2. The lower arms 5 and 5 extend inward in the vehicle width direction, and the other ends are connected to the vehicle body.

As shown in FIG. 2, the lower arms 5 and 5 of the present embodiment are made of plate-like elastic bodies whose thickness direction is vertically oriented, and the wheel 1 side end is formed into a fork. The wheel side mounting portion 5d is configured. The wheel-side mounting portion 5c is connected to the wheel support member 2 at a position lower than the rotation center axis of the wheel 1, and the vehicle-body-side mounting portion 5c.
d is rigidly connected to the vehicle body so as not to rotate at least in the vertical direction.

Further, in the lower arm 5, a plurality of notches 6 (rigidity changing means) extending in the front-rear direction of the vehicle body are respectively provided on the lower surface of the vehicle body side portion 5a and the upper surface of the wheel side portion 5b along the vehicle body width direction. Has been formed. As a result, the vehicle-body-side portion 5a of the lower arm 5 opens between the notches 6 with respect to an upward bending moment, and the notch 6 portions have a significantly reduced resistance to tensile force. The flexural rigidity is the same as that of the elastic body having a thickness excluding the six portions, and the flexural rigidity in the upward direction is weakened. Further, with respect to a downward bending moment, the facing surfaces between the cuts 6 are brought into contact with each other and pressed against each other to resist the compressive force, so that the same flexural rigidity as in the case without the cuts 6 is secured.

That is, the vehicle body side portion 5a of the lower arm 5 is
With respect to the bending input in the vertical direction, the bending is set to be more easily bent upward than downward. On the other hand, the lower arm 5
The wheel-side portion 5b of each of the notches 6 is opened between the notches 6 with respect to a downward bending moment, and the notch 6 portion has a significantly reduced resistance to tensile force. The flexural rigidity is the same as that of the elastic body having the removed thickness. For this reason, the wheel side portion 5b is set to have a low downward bending rigidity.

In addition, against the upward bending moment, the facing surfaces between the cuts 6 are brought into contact with each other and pressed against each other to resist the compressive force, so that the bending rigidity to the same level as that without the cuts 6 is provided. Is secured. That is, the wheel-side portion 5b of the lower arm 5 is set so as to bend more downward than upward with respect to the bending input in the vertical direction.

Next, the operation of the vehicle suspension system provided with the lower arm 5 made of such an elastic body will be described. In addition, in this vehicle suspension device, the lower arm 5 is configured as shown in FIG.
As shown in (b), the wheel-side mounting portion 5d is set to a slightly lower position than the vehicle-body-side mounting portion 5c to reduce the camber change in the positive direction at the time of bounce, as shown in FIG. At the same time, the camber change in the positive direction at the time of rebound is increased to make the ground camber angle closer to zero.

First, considering the case where the wheel 1 bounces, as shown in FIG. 3, in the lower arm 5, an upward load is input to the wheel side mounting portion 5d and the upward bending moment causes the vehicle body side. The wheel-side mounting portion 5d moves upward while bending around the mounting portion 5c as a fulcrum. In addition,
Since the vehicle body side mounting portion 5c is rigidly fixed to the lower arm 5, the lower arm 5 is in a bending state similar to that of a cantilever.

At this time, in the lower arm 5, the notch 6 of the vehicle body side portion 5a is opened as described above, and the bending rigidity of the vehicle body side portion 5a becomes weaker than that of the wheel side portion 5b. Therefore, the wheel-side portion 5b does not bend so much, and the vehicle-body-side portion 5a relatively bends significantly. Therefore, since the vehicle body side portion 5a near the vehicle body side attachment portion 5c and the wheel side attachment portion 5d turn in a substantially linear state, the locus of the wheel side attachment portion 5d is a rigid body of the lower arm 5. It approaches the locus of the wheel-side mounting portion 5d in the case of being configured.

Considering the case where the wheel 1 rebounds, as shown in FIG. 4, in the lower arm 5, a downward load is input to the wheel side attachment portion 5d, and the downward bending moment causes the vehicle body side to move. The wheel-side mounting portion 5d bends downward with the mounting portion 5c as a fulcrum and moves downward. At this time, in the lower arm 5, the notch 6 of the wheel side portion 5b is opened as described above, and the bending rigidity of the wheel side portion 5b becomes weaker than that of the vehicle body side portion 5a.

For this reason, the vehicle body side portion 5a does not bend so much, and only the wheel side portion 5b largely bends downward, and the span between the vehicle body side mounting portion 5c and the wheel side mounting portion 5d when rebounding. The length is shorter than that of the conventional elastic connecting member that does not have the notch 6. As described above, in the lower arm 5 of this embodiment, the displacement of the wheel-side mounting portion 5d inward in the vehicle width direction is smaller than that of the conventional elastic connecting member having no notch 6 at the time of bouncing. ,
As the lower arm 5 is made closer to a rigid body, it becomes larger at the time of rebound as compared with a conventional elastic connecting member having no notch 6.

This is done via the knuckle spindle 2.
Since it is input as the displacement in the vehicle width direction of the lower position with respect to the upper position of the wheel 1, it directly affects the camber angle of the wheel 1. When this is calculated as the camber change occurring in the wheel 1, it becomes as shown in FIG. Here, the alternate long and short dash line B is the camber characteristic of the lower arm 5 made of a conventional elastic body without the notch 6, and the broken line C is the camber characteristic when the lower arm 5 is made of a rigid body. Further, T indicates the position where the ground camber angle is zero.

As can be seen from FIG. 5, when the wheel 1 bounces, the conventional elastic connecting member without the notch 6 increases the camber change in the positive direction more than the lower arm 5 made of a rigid body. It can be seen that the lower arm 5 has a camber characteristic close to that of the lower arm 5 made of a rigid body, with the increase in the positive direction decreasing.

This reduces the increase in camber change in the positive direction with respect to the outer wheel at the time of turning, which occurs when the lower arm 5 is made of an elastic body, and reduces the camber angle of the wheel 1 in the direction away from zero ground camber angle. It is possible to reduce the deterioration of the turning performance on the turning outer wheel side when the lower arm 5 is made of an elastic body that is displaced. Further, when rebounding, the camber change can be increased in the positive direction as compared with the case where the notch 6 is not provided, and the ground camber angle can be made closer to zero, and the grip force of the tire can be increased. Can be pulled out reliably.

As described above, the lower arm 5 of this embodiment is
No. 5 has a relatively low bending rigidity downward in the wheel side portion and a low bending rigidity upward in the vehicle body side portion, so that the wheel side mounting portion 5d is separated from the vehicle body side mounting portion 5c during bouncing. When the vehicle rebounds, the wheel side mounting portion 5d is moved to the vehicle body side mounting portion 5c.
Can be displaced in the direction of approaching.

Therefore, the span between the vehicle body side mounting portion 5c and the wheel side mounting portion 5d becomes longer when the wheel 1 bounces, and approaches the span when the lower arms 5, 5 are made of a rigid body. It is possible to suppress an increase in the change in the camber in the positive direction at the time of bouncing when the elastic body is formed of. Further, when the wheel rebounds, the span between the vehicle body side mounting portion 5c and the wheel side mounting portion 5d is further shortened to increase the camber change in the positive direction at the time of rebounding and the inner camber angle of the inner wheel at the time of turning to zero. It is possible to prevent the tire from being unevenly worn, the grip force of the tire is increased, and the turning stability is improved.

In the above embodiment, the suspension system for a strut type vehicle has been described, but the upper arm 7 is provided above the knuckle spindle 2 as in the second embodiment shown in FIG.
It may be adopted in a suspension system for a double wishbone type vehicle in which is provided. Also in this case, similarly to the above, by configuring the lower arm 5 with an elastic body, an increase in camber change in the positive direction at the time of bounding can be suppressed and
By configuring with the elastic body provided with the notch 6 as described above, the increase amount of the camber change in the positive direction at the time of rebound can be set to be large.

Further, as in the third embodiment shown in FIG. 7, the upper arm 7 is also made of an elastic body, and the upper arm 7 has a plurality of upper body 7b upper surfaces and wheel side 7a lower surfaces, each extending in the vehicle front-rear direction. The notch 8 may be formed along the width direction of the vehicle body to provide the rigidity changing means.
In this case, in the upper arm 7, the wheel side portion 7a easily bends with respect to the upward bending moment, and the vehicle body side portion 7b easily bends with respect to the downward bending moment.

Therefore, the upper arm 7 largely bends at the vehicle body side portion 7b with respect to the downward bending moment due to the downward input to the wheel side attachment portion 7c, and the upper arm 7 is moved from the vehicle body side portion to the wheel side attachment portion. In the case where the upper arm 7 is made of a rigid body, the relative displacement of the wheel-side mounting portion 7c inward in the vehicle width direction due to the fact that the upper arm 7 is made of an elastic body while turning while maintaining a substantially straight line between the 7c The displacement can be close to.

Further, as to the upward bending rigidity due to the upward input to the wheel-side mounting portion 7c, the wheel-side portion 7a is largely bent, so that the notch 8 is not provided. The inward displacement in the vehicle width direction becomes large. Since the displacement of the upper arm 7 in the vehicle body width direction is a relative displacement of the upper position of the wheel 1 in the vehicle body width direction via the knuckle spindle 2, it is more than in the case where only the lower arm 5 is made of the elastic body. Furthermore, the increase amount of the camber change in the negative direction at the time of bouncing is set to be large.

FIG. 8 shows the actual camber change at the time of bound / rebound. Here, T indicates a position where the camber angle to the ground is zero, A1 indicates a case where the upper arm 7 is made of a rigid body and the lower arm 5 is made of the elastic connecting member of the above-described embodiment, and A2 is an upper arm 7 and a lower arm 5. Both show the case where the elastic connecting members described above are used.

As a comparative example, C shows the case where both the upper arm 7 and the lower arm 5 are made of rigid bodies, and D shows the conventional elastic connecting member in which the rigidity changing means is not provided in the lower arm 5. The case where the upper arm 7 is made of a rigid body is shown. As can be seen from FIG. 8, the camber change in the negative direction at the time of bouncing is
It can be set to earn more than the case where both arms are made of rigid bodies, and the ground camber angle of the wheel 1 at the time of bouncing can be brought closer to zero.

As described above, the upper arm 7 of this embodiment is
Relatively lowers the bending rigidity downward in the vehicle body side portion 7c and the upward bending rigidity in the wheel side portion 7d. Therefore, at the time of bouncing, the wheel side mounting portion 7d becomes the vehicle body side mounting portion 7c. While displacing in the approaching direction,
At the time of rebound, the wheel side mounting portion 7d can be displaced in a direction away from the vehicle body side mounting portion 7c.

Therefore, the span between the vehicle body side mounting portion 7c and the wheel side mounting portion 7d becomes longer when the wheel 1 rebounds, and the displacement inward in the vehicle width direction when the upper arm 7 is made of an elastic body is reduced. Since the upper arm 7 is close to the span when the upper arm 7 is made of a rigid body, it is possible to suppress an increase in the camber change in the negative direction at the time of rebound due to the upper arm 7 being made of an elastic body.

Further, when the wheel bounces, the span between the vehicle body side mounting portion 7c and the wheel side mounting portion 7d is further shortened to increase the camber change in the negative direction at the time of bouncing, and the ground camber of the outer wheel at the time of turning. It is possible to make the angle even closer to zero, prevent uneven wear of the tire, increase the grip force of the tire, and improve turning stability.

In the above embodiment, the double wishbone type suspension system for vehicles is constituted by an elastic connecting member in which the lower arms 5 or both the lower arms 5 and the upper arms 7 are provided with the notches 6 and 8 as rigidity changing means. Although the above example is shown, only the upper arm 7 may be configured by an elastic connecting member provided with the notch 8 as a rigidity changing means.

Next, a fourth embodiment will be described. The vehicle suspension system according to the fourth embodiment is a trailing link type rear wheel suspension system in which the trailing arm 4 is composed of an elastic connecting member extending in the vehicle front-rear direction as shown in FIG. is there. The trailing arm 4 is rigidly attached to the vehicle body at least around the axis in the vehicle width direction, extends rearward in the vehicle front-rear direction, and has the other end rigidly connected to the knuckle spindle 2.

Further, the trailing arm 4 is provided with a plurality of notches 9 extending in the vehicle body width direction along the axial direction on the lower surface of the vehicle body side portion 4b and the upper surface of the wheel side portion 4a. In such a vehicle suspension system,
If the elastic connecting member is not provided with rigidity changing means,
Compared with the case where the arm is made of a rigid body, the wheel-side mounting portion 5d when the wheel 1 bounces is largely displaced forward in the vehicle body front-rear direction. This is the wheel 1 when bound
Of the wheel 1 and the wheel house, and the layout is disadvantageous.

However, in the present embodiment, by providing the notches as described above, as shown in FIG. 10A, at the time of bouncing, the bending rigidity of the vehicle body side portion 4b to the upper side as compared with the wheel side portion 4a is increased. Is lower, the movement of the wheel-side mounting portion 5d in the front-rear direction of the vehicle body is smaller than in the case where the notch 9 is not provided. This makes it possible to suppress the forward movement of the vehicle body in the front-rear direction at the time of bouncing as compared with the conventional one, and even if an elastic body is adopted for the trailing arm 4, the interference between the wheel 1 and the wheel house at the time of bouncing is suppressed. It is not a disadvantage.

Further, at the time of rebound, FIG. 10 (b)
As shown in FIG.
Since the flexural rigidity of the wheel-side mounting portion 4c is low, the flexure angle of the wheel-side mounting portion 4c becomes larger than that of the related art. Therefore, as compared with the conventional elastic connecting member in which the notch 9 is not provided, the instantaneous rotation center of the suspension moves upward, so that the anti-lift characteristic is improved.

In order to confirm this, the locus of the wheel center of the rear wheel is obtained and viewed, as shown in FIG.
Here, the solid line A shows the case where the trailing arm 4 is an elastic connecting member provided with the rigidity changing means. Further, as a comparative example, the alternate long and short dash line B shows the case of a conventional elastic connecting member not provided with the rigidity changing means, and the broken line C is
The case of a rigid arm is shown.

As described above, in the trailing arm 4 of this embodiment, the downward bending rigidity of the wheel side portion is set relatively low and the upward bending rigidity of the vehicle body side portion is set relatively low. When the wheel 1 bounces, the span between the vehicle body side mounting portion 4c and the wheel side mounting portion 4d becomes long. Therefore, when the trailing arm 4 is made of an elastic body, the wheel moves forward and backward in the vehicle body front and rear direction. It is possible to avoid interference between the wheel and the wheel house at the time of bouncing due to the trailing arm 4 being made of an elastic body.

Further, when the wheel rebounds, the span between the vehicle body side mounting portion 4c and the wheel side mounting portion 4d becomes short, and the deflection angle at the vehicle body mounting portion position 4c becomes large. It is also possible to improve the anti-lift characteristics by moving the above. In all the above-mentioned embodiments, the notches 6, 8, 9 are provided on the upper surface or the lower surface, and the notches 6, 8, 9
The flexural rigidity in the direction opposite to the direction in which the
The rigidity changing means is not limited to this, and is not limited to this.
As shown in FIG. 2, a plurality of grooves 10 are engraved along the axis in the direction orthogonal to the axis on the surface side where the flexural rigidity is desired to be weakened, and in the axial direction of the arm so as to connect the peaks of the grooves 10. Alternatively, a fiber member (for example, reinforced glass fiber) 11 that has a foldability and does not expand or contract may be fixed along the path.

In this case, when a bending moment in the direction in which the fiber member 11 is provided is input, the fiber member 1
No. 1 is bent and the fiber member 11 does not resist the compressive force, and the compressive force is set lower by the amount of the groove 10, so that the flexural rigidity in that direction is set lower. Further, when a bending moment is input in the opposite direction, a tensile force is input to the side where the fiber member 11 is provided, but the fiber member 11 resists the tensile force, so that the flexural rigidity is increased.

When this is used for the lower arm 5, as shown in FIGS. 12 and 13, by providing it on the upper surface of the vehicle body side portion 5a and the lower surface of the wheel side portion 5b, the same effect as described above can be obtained. At this time, both ends of the fiber member 11 and intermediate positions thereof may be fixed to the elastic body without using the groove 10 to serve as the rigidity changing means.

In this case, with respect to the input in the direction in which the fibrous member 11 is fixed, the fibrous member 11 does not flex and resist, but the flexural rigidity of the elastic body itself, and the input in the opposite direction. On the other hand, since the fiber member 11 is pulled and resists, the flexural rigidity is increased. Further, in all of the above-mentioned embodiments, the rigidity changing means is provided on both the wheel side portion and the vehicle body side portion of the connecting member, but for example, when it is desired to exert the above-mentioned action only at the time of bouncing in the lower arm 5. ,
For example, the rigidity changing means may be provided only on the vehicle body side portion 5a, or when the above-mentioned action is exerted only at the time of bouncing, for example, the rigidity changing means may be provided only on the wheel side portion 5b. In this way, the rigidity changing means may be provided only on one of the vehicle body side portion and the wheel side portion depending on the purpose.

Further, in the above embodiment, the notch 6 which is the rigidity changing means is linearly extended, but it may be formed so as to extend in the direction orthogonal to the axis while meandering in a wave shape or a sawtooth shape. . By doing so, the rigidity with respect to the input from the direction orthogonal to the axis of the elastic connecting member can be improved as compared with the case where the cut 6 is formed in a straight line.

Further, the rigidity changing means by the notch is provided on the vehicle body side portion, and the rigidity changing means by the fiber member is provided on the wheel side portion. Alternatively, a plurality of rigidity changing means may be provided in the same portion of the vehicle body side portion, such as a notch provided on the upper surface side and a fiber member on the lower surface side.

Further, since the rigidity changing means is an example, the rigidity changing means may be provided by burying a fiber member only on the lower surface side of the wheel side portion 5b of the elastic lower arm 5, for example. It is needless to say that the elastic body shown in the above embodiment can be formed by using a leaf spring, a reinforced fiber resin, or the like.

Since the flexural rigidity of the elastic connecting member and the deformation state by these rigidity changing means can be analyzed by a known means such as the finite element analysis method, the flexural rigidity desired from the analysis result, Needless to say, it is possible to set the optimum rigidity changing means for obtaining the deformation state and the like.

[0067]

As described above, in the suspension system for a vehicle of the present invention, changes in the span between the wheel side attachment portion and the vehicle body side attachment portion of the elastic coupling member at the time of bouncing and rebounding of the wheel are individually changed. It becomes possible to set, and it is possible to suppress the positive camber at the time of bounce and increase the positive camber at the time of rebound.

Therefore, the wheel-to-ground camber can always be brought close to zero, uneven wear of the tire can be prevented, the grip force of the tire can be increased, and turning stability can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a vehicle suspension according to an embodiment of the present invention.

2A and 2B are views showing a lower arm of an embodiment according to the present invention, in which FIG. 2A is a perspective view thereof and FIG. 2B is a side view thereof.

FIG. 3 is a side view showing a state in which the lower arm of the embodiment according to the present invention is bound.

FIG. 4 is a side view showing a state in which the lower arm of the embodiment according to the present invention has rebounded.

FIG. 5 is a diagram showing changes in camber at the time of bouncing and rebounding according to the embodiment of the present invention.

FIG. 6 is a perspective view showing a connecting member according to a second embodiment of the present invention.

FIG. 7 is a perspective view showing a connecting member according to a third embodiment of the present invention.

FIG. 8 is a diagram showing changes in camber at the time of bound / rebound in the second and third examples according to the present invention.

FIG. 9 is a perspective view showing a trailing arm according to a fourth embodiment of the present invention.

FIG. 10 is a side view showing a bound / rebound state of a fourth embodiment according to the present invention.

FIG. 11 is a diagram showing a locus of a wheel center according to a fourth embodiment of the present invention.

FIG. 12 is a side view showing an elastic connecting member of a fifth embodiment according to the present invention.

FIG. 13 is a side view showing a state of the elastic connecting member according to the fifth embodiment of the present invention at the time of bound / rebound.

FIG. 14 is a view showing the operation of the rigidity changing member at the time of bouncing according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 wheel 2 wheel support member 4 trailing arm 5 lower arm (elastic connecting member) 5a wheel side portion 5b vehicle body side portion 5c vehicle body side mounting portion 5d wheel side mounting portion 6,8,9 notch (stiffness changing means) 7 upper arm 10 groove 11 Fiber member (rigidity changing means)

Claims (3)

[Claims] 1. A wheel supporting member for rotatably supporting a wheel and a vehicle body side member are connected to each other, and an end portion on the vehicle body side is attached to the vehicle body side member so as not to be vertically rotatable with respect to the vehicle body. And a rigidity changing means is provided in at least one of a vehicle body side portion and a wheel side portion of the elastic connecting member. The vehicle suspension device characterized in that the rigidity changing means changes the bending rigidity of the elastic coupling member upward or downward with respect to the other when the wheel is bound or rebounded. 2. The rigidity changing means includes a notch extending on an upper surface side or a lower surface side of at least one of a vehicle body side portion and a wheel side portion of the elastic connecting member, the notch extending in a direction substantially orthogonal to an axial direction of the elastic connecting member. The vehicle suspension device according to claim 1, wherein the suspension device is formed along an axial direction of the elastic connecting member. 3. The rigidity changing means comprises a fiber member which is flexible in the vertical direction and has a predetermined hardness in the axial direction,
The vehicle suspension device according to claim 1, wherein the elastic connecting member is fixed to the upper surface side or the lower surface side along the axial direction of the elastic connecting member.