JPH04293606A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To provide a suspension device capable of suppressing the toe-out tendency of a wheel setting the wheel to the toe-in tendency at the time of deceleration without reducing the riding comfortableness and space efficiency of a vehicle and complicating a structure. CONSTITUTION:The vehicle body inside member 3d of a bush 3b in front of a vehicle body and the vehicle body outside member 3g of a bush 3c at the rear of the vehicle body among bushes inserted between vehicle body side end sections 1b, 1c of an A-arm 1 and a shaft 4a are made of a material with a negative Poisson's ratio respectively. The members 3d, 3g are increased in size in the lateral direction of a vehicle in response to the component force in the longitudinal direction of the vehicle during deceleration, thus the toe-out tendency of a wheel 2 is suppressed.

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 a suspension system for a vehicle that can suppress the tendency of wheels to toe out or make them tend to toe in during braking.

0002

2. Description of the Related Art The structure of a vehicle suspension device according to a first prior art will be explained with reference to FIG. Here, FIG. 9 is a configuration diagram of a suspension device applied to the left rear wheel of a vehicle, viewed from above the vehicle.

Reference numeral 1 denotes an A-arm, which is provided as a link member that connects the vehicle body and the wheels. A-arm 1
The wheel side end portion 1a is swingably connected to a wheel support member 2a that rotatably supports the wheel 2, and the vehicle body side end portions 1b and 1c are connected to bushes 3b and 3c and a shaft 4a, respectively. It is swingably connected to the vehicle body side support member 4 via.

[0004] In such a vehicle suspension system (hereinafter referred to as an A-arm type suspension system), so-called compliance steering can be achieved in response to the input to the wheels 2 by appropriately setting the elastic coefficients of the bushes 3b and 3c. It is possible to cause

FIG. 10 is a schematic diagram of the A-arm type suspension device viewed from above the vehicle when the vehicle is accelerating.
FIG. 11 is a schematic diagram of the rear suspension device viewed from above the vehicle when the vehicle is decelerating. During acceleration, a force in the forward direction of the vehicle body acts on the wheels 2, so as shown in FIG.
tends to toe-in. On the other hand, during deceleration, a force in the rearward direction of the vehicle body acts on the wheel 2, so as shown in FIG. 11, the bush 3b is compressed on the inside of the vehicle body, the bush 3c is compressed on the outside of the vehicle body, and the wheel 2 tends to toe out. .

In addition, as shown in FIG. 12, apart from the A-arm type suspension device, two front links 21 and two rear links 22 are used as link members instead of the A-arm 1.
A suspension device (hereinafter referred to as a parallel link type suspension device) is known that is provided substantially parallel to the lateral direction of the vehicle and connects the wheel support member 2a and the vehicle body side support member 4 by these.

In this suspension device, the vehicle body side ends 21b and 22c of the front link 21 and the rear link 22
However, like the A-arm type suspension device, Bush 3
b and 3c and the shaft 4a, and the wheel side end 21a of the front link 21 is connected to the wheel support member 2a through the bush 3h and the shaft 2b. The wheel side end portion 22a of the rear link 22 is swingably connected to the wheel support member 2a via the bush 3i and the shaft 2b.

The parallel link type suspension device during deceleration will be explained with reference to FIG. 13. wheel 2
When a force in the rearward direction of the vehicle is applied to the bushes 3b, 3
i is compressed on the outside of the vehicle body, and at the same time, bushes 3c and 3h are compressed on the inside of the vehicle body. Here, bushes 3b, 3c,
As long as the elastic coefficients of 3h and 3i are the same, the front link 2
1, the rear link 22, and the shafts 2b and 4a are displaced while maintaining parallelism, so no toe change occurs.

However, as shown in FIG. 14, for example, the elastic modulus of the bushes 3h and 3i is lower than that of the bushes 3b and 3c.
Bushes 3b, 3c, 3h, 3i, etc.
If there are variations in the elastic coefficient of the bush 3b when a force is applied to the wheel 2 in the rearward direction of the vehicle,
, 3c, 3h, and 3i, and the shaft 2b
and the axis 4a cannot maintain parallelism. As a result, even in the parallel link type suspension device, the wheels 2 may exhibit a tendency to toe out.

[0010] As described above, in the conventional suspension system, the wheels 2 may exhibit a tendency to toe out during deceleration, and this causes a large change in the attitude of the vehicle when turning. Stability may decrease. Here, in order to suppress the toe-out tendency, the elastic modulus of the bushes 3b, 3c, etc. may be set large, or the bushes 3b, 3c, etc. may be disposed approximately in the longitudinal direction of the vehicle between the wheel support member 2a and the vehicle body. Radius rod (not shown) that restricts displacement in the approximately longitudinal direction of the vehicle
It is necessary to set the rigidity of the vehicle to a large value, which may impair the ride comfort of the vehicle.

In view of this problem, as a second prior art, Japanese Utility Model Application Publication No. 129606/1983 discloses a technique for suppressing the tendency of the wheels 2 to toe out even during braking.

That is, as shown in FIG.
In addition to the configuration of the first prior art related to the arm-type suspension device, an actuator 6 is provided which uses the hydraulic pressure from the brake device 5 as a power source, and when braking, the actuator 6 is actuated by a brake switch 8 that is activated when the brake pedal 7 is depressed. The solenoid valve 9 is operated to introduce the hydraulic pressure from the brake device 5 to the actuator 6, and the vehicle body side support point 1 is
It is configured to press c toward the outside of the vehicle body. As a result, the inner side of the bush 3c is compressed during braking, so the toe-out of the wheel 2 can be avoided without setting the elastic coefficients of the bushes 3b, 3c, etc. large toward the outside of the vehicle body, or without setting the rigidity of the radius rod large. It becomes possible to suppress the tendency.

[0013]

[Problems to be Solved by the Invention] The second prior art requires the actuator 6, a means for supplying hydraulic pressure to the actuator 6, a solenoid valve 9, etc., resulting in decreased space efficiency and structural problems. This has the problem of complicating the process.

In view of the above problems, the present invention suppresses the tendency of the wheels 2 to toe out even during deceleration without reducing space efficiency or complicating the structure, and without impairing the ride comfort of the vehicle. Alternatively, it is an object of the present invention to obtain a suspension device that can make the wheels 2 tend to toe-in.

[0015]

[Means for solving the problem] In order to solve the above problem,
In the invention according to claim 1, the wheel side end portion is connected to the wheel support member, and the vehicle body side end portion is provided with two front and rear supports to the vehicle body side support member via an annular elastic member whose axis is in the longitudinal direction of the vehicle. In a suspension device having link members connected at points, the elastic members are two members, an inner member of the vehicle body and an outer member of the vehicle body, and the elastic member interposed at the support point at the front of the vehicle connects the inner member of the vehicle body with a Poisson ratio. The outer member of the vehicle body is made of a material with a Poisson's ratio, and the elastic member inserted at the support point at the rear of the vehicle is made of a material with a Poisson's ratio. It is characterized by being made of a material with a negative Poisson's ratio.

In the invention as claimed in claim 2, the elastic member is disposed substantially parallel to the lateral direction of the vehicle, and the wheel side end portion and the vehicle body side end portion are connected to each other via an annular elastic member whose axis is in the longitudinal direction of the vehicle. 2 connected to the wheel support member and the vehicle body side support member.
In a suspension device having a book link member,
The elastic members on the vehicle body side are composed of two members, an inner member of the vehicle body and an outer member of the vehicle body.As for the elastic members interposed at the support points at the front of the vehicle, the inner member of the vehicle body is made of a material with a negative Poisson's ratio, and the outer member of the vehicle body is made of a material with a negative Poisson's ratio. The elastic member interposed at the support point at the rear of the vehicle is made of a material with a positive Poisson's ratio, and the inner member of the vehicle body is made of a material with a positive Poisson's ratio, and the outer member of the vehicle body is made of a material with a negative Poisson's ratio. This is a characteristic feature.

Further, in the invention according to claim 3, the wheel side end portion and the vehicle body side end portion are arranged substantially parallel to the lateral direction of the vehicle, and the annular elastic member has an annular elastic member having an axis in the longitudinal direction of the vehicle. 2 connected to the wheel support member and the vehicle body side support member.
In a suspension device having a book link member,
The elastic member on the side of the wheel support member is made of two members, an inner member of the vehicle body and an outer member of the vehicle body, and the elastic member interposed at the support point at the front of the vehicle is made of a material having a Poisson's ratio for the inner member of the vehicle body,
The outer member of the vehicle body is made of a material with a negative Poisson's ratio, and the elastic member interposed at the support point at the rear of the vehicle is made of a material with a negative Poisson's ratio, and the outer member of the vehicle body is made of a material with a positive Poisson's ratio. It is characterized by consisting of the following.

[0018]

[Operation] In the invention according to claims 1 and 2, when the vehicle decelerates, the force acting on the wheels in the rearward direction of the vehicle causes the elastic member located at the front of the vehicle among the elastic members on the vehicle body side to be compressed on the inside of the vehicle body. , the outer side of the elastic member at the rear of the vehicle is compressed, but the inner side of the elastic member at the front of the vehicle and the outer side of the elastic member at the rear of the vehicle are both made of materials with a negative Poisson's ratio, so these The size of the member increases in the lateral direction of the vehicle due to the force acting on the member in the longitudinal direction of the vehicle, thereby suppressing the tendency of the wheel to toe-out or causing the wheel to tend to toe-in.

Further, in the invention according to claim 3, the outer side of the vehicle body of the elastic member located at the front of the vehicle among the elastic members on the side of the wheel support member is compressed due to the force acting in the rear direction of the vehicle on the wheels when the vehicle is decelerated. At the same time, the inner side of the elastic member at the rear of the vehicle is compressed, but both the outer member of the elastic member at the front of the vehicle and the inner member of the vehicle body of the elastic member at the rear of the vehicle are made of materials with a negative Poisson's ratio. The dimensions of these members increase in the lateral direction of the vehicle due to forces acting on these members in the longitudinal direction of the vehicle, thereby suppressing the tendency of the wheels to toe out or causing the wheels to tend to toe in.

[0020]

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. Note that the same components as those in the prior art are given the same reference numerals to simplify the explanation.

FIG. 1 is a block diagram of a suspension device according to a first embodiment of the present invention, and FIG.
A sectional view, and FIG. 2(b) is a BB sectional view of FIG. In this embodiment, the present invention is applied to an A-arm type suspension device.

The bush 3b as an elastic member provided at the front of the vehicle is composed of an inner member 3d of the vehicle body and an outer member 3e of the vehicle body.The inner member 3d of the vehicle body has a negative Poisson's ratio, and the outer member 3e of the vehicle body has a negative Poisson's ratio. is positive. Also,
Similarly to the bush 3b, the bush 3c provided at the rear of the vehicle is composed of an inner member 3f of the vehicle body and an outer member 3g of the vehicle body, and the Poisson's ratio of the inner member 3f of the vehicle body is positive, and the Poisson's ratio of the outer member 3g of the vehicle body is negative. It is.

A material having a negative Poisson's ratio will be explained with reference to FIG. Here, FIG. 3(a) is a schematic diagram showing the structure of the material in an initial state, and FIG. 3(b) is a schematic diagram showing the structure of the material in a state where a tensile force is applied.

For example, polytetrafluoroethylene (hereinafter referred to as PTFE) is known as a material having a negative Poisson's ratio. As shown in the model, PTFE has a disc-shaped minute piece 1 in its initial state as shown in Figure 3(a).
5 are connected by a thread 16, but when a tensile force is applied in the horizontal direction in the figure, the minute piece 15 is pulled by the thread 16 and rotates, as shown in FIG. The dimension in the direction, that is, the thickness increases.

In this embodiment, materials having a negative Poisson's ratio are arranged as the inner member 3d and outer member 3g so that the thickness increases when a tensile force is applied in the longitudinal direction of the vehicle. . Specifically, the material having a negative Poisson's ratio is arranged so that the left-right direction in FIG. 3 is substantially parallel to the longitudinal direction of the vehicle.

Next, the operation of the embodiment of the present invention will be explained with reference to FIGS. 4 and 5. Here, FIG. 4 is a schematic diagram of the rear suspension device viewed from above the vehicle when the vehicle is accelerating, and FIG. 5 is a schematic diagram of the rear suspension device viewed from above the vehicle when the vehicle is decelerated.

When the vehicle accelerates, a force in the forward direction of the vehicle acts on the wheel 2, so the outer member 3e of the vehicle body is compressed in the bush 3b at the front of the vehicle, and the inner member 3f of the vehicle body is compressed in the bush 3c at the rear of the vehicle. 2 indicates a tendency toward toe-in. At this time, the Poisson's ratio of the inner vehicle body member 3d of the bush 3b and the outer vehicle body member 3g of the bush 3c is negative, and a force in the longitudinal direction of the vehicle acts on the inner vehicle body member 3d and the outer vehicle body member 3g, so that the member 3d and 3g increases in the vehicle lateral direction, so the toe-in tendency of the wheel 2 is stronger than the toe-in tendency of the first prior art related to the A-arm type suspension device shown by the two-dot chain line.

On the other hand, during deceleration, a force in the rearward direction of the vehicle acts on the wheel 2, so the bush 3b compresses the vehicle body inner member 3d, and the bush 3c compresses the vehicle body outer member 3g, but the vehicle body inner member 3d and the bush 3c compress the vehicle body outer member 3g. When a force in the longitudinal direction of the vehicle acts on the outer member 3g of the vehicle body, the dimensions of the members 3d and 3g increase in the lateral direction of the vehicle, so the tendency to toe out of the wheel 2 is suppressed as compared to the first conventional technique indicated by the two-dot chain line. be done.

As described above, in this embodiment, by using a material with a negative Poisson's ratio for the vehicle body inner member 3d of the bush 3b and the vehicle body outer member 3g of the bush 3c, a decrease in space efficiency and a complication of the structure can be avoided. without inviting
It is possible to obtain a vehicle suspension device that can suppress the tendency of the wheels 2 to toe out even during deceleration. Furthermore, in this embodiment, there is no need to set the elastic coefficients of the bushes 3b and 3c large in order to suppress the tendency of the wheels 2 to toe out, and there is no need to set the rigidity of the radius rod large, which impairs the ride comfort of the vehicle. There is little risk.

Next, a second embodiment of the present invention will be described with reference to FIG. Here, FIG. 6 is a configuration diagram of a suspension device according to a second embodiment of the present invention. In this embodiment, the present invention is applied to a parallel link type suspension device.

In this embodiment, the bushes 3b and 3c are made of a material having a negative Poisson's ratio on the inside member 3d of the vehicle body and the outside member 3g of the vehicle body, and the thickness of the bushes 3b and 3c increases when a tensile force is applied in the longitudinal direction of the vehicle. are arranged so that the intensity increases. The other configurations are similar to the first prior art related to a parallel link type suspension device.

In this embodiment, as in the first embodiment, the force acting in the rearward direction of the vehicle body on the wheel 2 during deceleration causes the inner member 3d of the vehicle body of the bush 3b and the bush 3c to
The dimensions of the vehicle body outer member 3g increase in the vehicle lateral direction. As a result, the front link 21 is pulled into the vehicle body and the rear link 22 is pushed out toward the wheel, so that the front side of the shaft 2b is located relatively inside the vehicle body than the rear side. Therefore, as shown in FIG. 7, the wheel 2 exhibits a more toe-in tendency than the first prior art related to FIG. Ru.

As described above, in this embodiment, by using a material with a negative Poisson's ratio for the vehicle body inner member 3d of the bush 3b and the vehicle body outer member 3g of the bush 3c, a decrease in space efficiency and a complication of the structure can be avoided. without inviting
It is possible to obtain a suspension device that can make the wheels 2 tend to toe-in or suppress the toe-out tendency of the wheels 2 even during deceleration. Furthermore, in this embodiment, there is no need to set the elastic coefficients of the bushes 3b, 3c, 3h, and 3i large in order to suppress the tendency of the wheels 2 to toe out, and there is no need to set the rigidity of the radius rod large. There is little risk of deteriorating ride comfort.

In the second embodiment of the parallel link type suspension device, materials having a negative Poisson's ratio are used for the inner member 3d of the bush 3b on the vehicle body and the outer member 3g of the bush 3c. As shown in FIG. 8, the entire bushes 3b and 3c are made of a material with a Poisson's ratio. Instead, the bush 3h on the wheel support member 2a side is divided into two parts, an inner member 3j of the vehicle body and an outer member 3k of the vehicle body, and the bush 3i is connected to the vehicle body. Inner member 3l and vehicle outer member 3
It is also possible to use a material having a negative Poisson's ratio for the vehicle body outer member 3k and the vehicle body inner member 3l. As a result, the dimensions of the vehicle body outer member 3k of the bush 3h and the vehicle body inner member 3l of the bush 3i increase in the lateral direction of the vehicle due to the force acting on the wheel 2 in the rearward direction of the vehicle body during deceleration, and the front side of the shaft 2b increases in the rearward direction of the vehicle body. Since the wheel 2 is located on the inside of the vehicle body relative to the side, similarly to the second embodiment, the wheel 2
It is possible to make the wheel 2 more prone to toe-in than in the first prior art, or to suppress the tendency of the wheel 2 to toe-out.

Furthermore, if a material with a negative Poisson's ratio is used for all of the vehicle body inner member 3d, the vehicle outer member 3g, the vehicle outer member 3k, and the vehicle inner member 3l, the effects of the second embodiment described above can be more pronounced. .

[0036]

As described above, in the suspension device according to the invention as set forth in claims 1 and 2, among the elastic members on the vehicle body side, the elastic member at the support point at the front of the vehicle body is By using a material having a negative Poisson's ratio for the elastic member on the outer side of the vehicle body at the support point at the rear of the vehicle body, By using a material with a negative Poisson's ratio for the elastic member on the outer side of the vehicle body at the support point at the front of the vehicle body and the inner member for the elastic member at the support point at the rear of the vehicle body, it is possible to avoid reducing space efficiency or complicating the structure. Furthermore, it is possible to obtain a suspension device that can suppress the tendency of the wheels 2 to toe out or make the wheels 2 tend to toe in even during braking without impairing the riding comfort of the vehicle.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of an A-arm type suspension device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of FIG. 1;

FIG. 3 is a schematic diagram showing the structure of a material having a negative Poisson's ratio.

FIG. 4 is a schematic diagram of the A-arm type suspension device during acceleration in the first embodiment of the present invention, viewed from above the vehicle.

FIG. 5 is a schematic diagram of the A-arm type suspension device during deceleration in the first embodiment of the present invention, viewed from above the vehicle.

FIG. 6 is a configuration diagram of a parallel link type suspension device according to a second embodiment of the present invention.

FIG. 7 is a schematic diagram of a parallel link suspension device during deceleration in a second embodiment of the present invention, viewed from above the vehicle.

FIG. 8 is a schematic diagram showing another configuration in the second embodiment of the present invention.

FIG. 9 is a schematic diagram of the A-arm type suspension device according to the first prior art, viewed from above the vehicle.

FIG. 10 is a schematic diagram of the A-arm type suspension device during acceleration in the first prior art, viewed from above the vehicle.

FIG. 11 is a schematic diagram of the A-arm type suspension device during deceleration in the first prior art, viewed from above the vehicle.

FIG. 12 is a configuration diagram of a parallel link type suspension device according to the first prior art seen from above a vehicle.

FIG. 13 is a schematic diagram of the parallel link type suspension device during braking in the first prior art, viewed from above the vehicle.

FIG. 14 is a schematic diagram of the parallel link type suspension device during braking in the first prior art, viewed from above the vehicle.

FIG. 15 is a configuration diagram of an A-arm type suspension device according to a second prior art viewed from above a vehicle.

[Explanation of symbols]

1...A arm (link member) 1a, 21a, 22a...Wheel side end 1b, 1c, 21b, 22c...Vehicle body side end 2a...Wheel support member 3b, 3c, 3h, 3i...Bush (elastic member) 3d,
3f, 3j, 3l...vehicle body inner member 3e, 3g, 3k, 3
m...Vehicle body outer member 4...Vehicle body side support member 21...Front side link (link member) 22...Rear side link (link member)

Claims (3)

[Claims] Claim 1: The wheel side end portion is connected to the wheel support member, and the vehicle body side end portion is connected to the vehicle body side support member at two support points, front and rear, via an annular elastic member having an axis in the longitudinal direction of the vehicle. In the suspension device having a link member, the elastic member is made of two members, an inner member of the vehicle body and an outer member of the vehicle body, and the elastic member interposed at the support point at the front of the vehicle is such that the inner member of the vehicle body is made of a material having a negative Poisson ratio. The outer member of the vehicle body is made of a material with a positive Poisson's ratio, and the elastic member interposed at the support point at the rear of the vehicle is made of a material with a positive Poisson's ratio. A vehicle suspension device comprising a material comprising: [Claim 2] A wheel support member and a vehicle body side support member are arranged substantially parallel to the lateral direction of the vehicle, and the wheel side end portion and the vehicle body side end portion are connected to each other via an annular elastic member whose axis is in the longitudinal direction of the vehicle. In a suspension device having two link members connected to each other, the elastic members on the vehicle body side are two members, an inner member of the vehicle body and an outer member of the vehicle body, and the elastic member interposed at the support point at the front of the vehicle is the inner member of the vehicle body. is made of a material with a negative Poisson's ratio, the outer member of the vehicle body is made of a material with a positive Poisson's ratio, and the elastic member interposed at the support point at the rear of the vehicle is made of a material with a positive Poisson's ratio. A suspension device for a vehicle, characterized in that an outer member of the vehicle body is made of a material having a negative Poisson's ratio. 3. A wheel supporting member and a vehicle body supporting member are disposed substantially parallel to the lateral direction of the vehicle, and the wheel side end portion and the vehicle body side end portion are connected to each other via an annular elastic member whose axis is in the longitudinal direction of the vehicle. In a suspension device having two link members connected to the wheel support member, the elastic members on the side of the wheel support member are two members, an inner member of the vehicle body and an outer member of the vehicle body, and the elastic member interposed at the support point at the front of the vehicle is The inner member is made of a material with a positive Poisson's ratio, the outer member of the vehicle body is made with a material with a negative Poisson's ratio, and the elastic member interposed at the support point at the rear of the vehicle is made of a material with a negative Poisson's ratio. 1. A suspension device for a vehicle, characterized in that the outer member of the vehicle body is made of a material having a Poisson's ratio.