JPH0664435A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To prevent change in steering characteristics at the time of turning and racing of turning inner rings by reducing the load movement of each driving wheel with the roll center height lowered in a suspension device for a vehicle. CONSTITUTION:In order that the roll center height of each rear wheel is lowered by means of change in volume with driving force applied to each rear wheel, a communication pipe 12 is provided, which is communicated with a first liquid chamber 11, second liquid chambers 7 and 8 which are formed for respective bushes 10, 6 and 8 provided for a radius rod 4, a front barrel link 2 and a rear barrel link 3.

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 applied to driving wheels.

[0002]

2. Description of the Related Art Conventionally, as a vehicle suspension device, for example, one shown in FIG. 7 is known.

This device is a rear suspension device for FR vehicles, and is an axle 01 that rotatably supports rear wheels (not shown).
Is a front parallel link 02, a rear parallel link 03, a radius rod 04, and an A type upper link 05.
Is supported so as to be swingable with respect to the vehicle body. And
A bush is provided on each vehicle body support portion.

[0004]

However, in the above-mentioned conventional vehicle suspension device, since the roll center height is uniquely determined by the suspension stroke, the turning inner wheel side to the turning outer wheel side during turning. There is a problem in that the amount of load movement is large, and particularly in a vehicle equipped with a high-power engine, idling is likely to occur due to a change in steer characteristics during turning acceleration and a loss of load on the drive inner wheels.

That is, when the vehicle body is rolled, a load movement occurs in which one of the front and rear wheels has a larger load and the other has a smaller load. According to P127 of "Motion and Control of Car Body" (Kyoritsu Shuppan, Masato Abe), this load movement amount can be calculated by comparing the load movement amounts of the front and rear wheels with ΔW _f and ΔW _{r as} shown in FIG.
Then, ΔW _f = μW _s / d _f · [{h _s / (1 + k _r / k _f )} + (l _r / l) · h _f ] ... (1) ΔW _r = μW _s / d _r · [ {H _s / (1 + k _f / k _r )} + (l _f / l) hr] ... (2)

Here, k _f , k _r ; roll rigidity of front and rear suspension devices h _f , h _r ; roll center height of front and rear wheels from the ground d _f , d _r ; tread of front and rear wheels h _s ; Roll axis distances l _f , l _r ; Distance between front and rear axles and vehicle center of gravity in horizontal plane W _s ; Vehicle weight μW _s ; Inertia force acting on vehicle body.

As can be seen from the above equations (1) and (2), this load movement amount becomes larger as the roll center heights h _f and h _r from the ground are higher.

The present invention has been made in view of the above problems, and in a vehicle suspension device, a steer characteristic at the time of accelerating cornering due to a load moving amount reducing action of a drive wheel accompanying a decrease in roll center height. The challenge is to prevent changes and idling of the turning inner wheel.

[0009]

In order to solve the above problems, in a vehicle suspension device of the present invention, a suspension member is provided in order to reduce the roll center height of the drive wheels due to a change in the volume of the drive force due to input of the drive wheels. Further, a communication pipe is provided which connects the first liquid chamber and the second liquid chamber formed in each of the first elastic body and the second elastic body so that pressure can be transmitted.

That is, a first member having an axle member for rotatably supporting a drive wheel and a first elastic body connected to the axle member and elastically deformed by input of a driving force to the drive wheel.
A suspension member and the axle member,
A second suspension member having a second elastic body that defines a roll center height in the vehicle body support portion, a first liquid chamber and a second liquid chamber formed in each of the first elastic body and the second elastic body, and a drive There is provided a communication pipe that communicates the first liquid chamber and the second liquid chamber so that pressure can be transmitted in order to reduce the roll center height of the drive wheel due to volume change due to input of force to the drive wheel.

[0011]

When driving, the first elastic body provided on the first suspension member is elastically deformed by input of the driving force to the driving wheel. Due to the elastic deformation of the first elastic body, the volume of the first liquid chamber formed in the first elastic body is reduced, and the working fluid is guided to the second liquid chamber through the communication pipe, so that the volume of the second liquid chamber is reduced. Inflate.
Due to the expansion of the second liquid chamber formed in the second elastic body,
The second suspension member having the elastic body is displaced so as to lower the roll center height of the drive wheel.

As described above, since the roll center height of the drive wheels is lowered during driving, the amount of load movement of the drive wheels from the inner turning wheel to the outer outer wheel during acceleration turning is reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the structure will be described.

FIG. 1 is a perspective view showing a double-wishbone type vehicle rear suspension device of a first embodiment applied to a rear-wheel drive vehicle.

In FIG. 1, an axle 1 (corresponding to an axle member) rotatably supporting a rear wheel (not shown) which is a drive wheel.
Is a front parallel link 2 (corresponding to a second suspension member), a rear parallel link 3 (corresponding to a second suspension member), a radius rod 4 (corresponding to a first suspension member), and an A-type upper link 5 for rocking relative to the vehicle body. Supported as possible.

The front parallel link 2 is arranged below the axle in the vehicle width direction, and a front parallel link bush 6 (corresponding to a second elastic body) for defining the roll center height is provided on the vehicle body supporting portion thereof. Has been. A second liquid chamber 7 is formed inside the lower portion of the inner cylinder of the front parallel link bush 6.

The rear parallel link 3 is arranged below the axle in parallel with the front parallel link 2.
A rear parallel link bush 8 (corresponding to a second elastic body) that defines the roll center height is provided on the vehicle body support portion. And this rear parallel link bush 8
A second liquid chamber 9 is formed inside the lower portion of the inner cylinder.

The radius rod 4 is disposed below the axle in a diagonally front-rear direction of the vehicle, and a radius rod bush 10 (corresponding to a first elastic body) which is elastically deformed when a driving force is input is provided on a vehicle body support portion thereof. Has been. The radius rod bush 10 has a first liquid chamber 11 formed inside the rod-side position of the inner cylinder.

The first liquid chamber 11 and the second liquid chambers 7 and 9 are connected to each other by a communication pipe 12, and the inside thereof is filled with a working fluid.

In FIG. 1, 13 is a strut in which a shock absorber and a coil spring are coaxially arranged.
Supports the suspension load applied in the vertical direction.

Next, the operation will be described.

When the vehicle is accelerated by depressing the accelerator, a driving force that pushes the radius rod 4 toward the front of the vehicle from the rear wheels, which are the driving wheels, via the axle 1 acts.

By this driving force, the radius rod bush 10 is elastically deformed from the broken line state to the solid line state in FIG. 3, the first liquid chamber 11 of the radius rod bush 10 is crushed and the volume thereof is reduced, and the first liquid chamber is reduced. The working fluid flows from 11 to the communication pipe 12.

The working fluid that has flowed out flows into the second liquid chambers 7 and 9 of the bushes 6 and 8 of the front parallel link 2 and the rear parallel link 3 through the communication pipe 12,
The liquid chambers 7 and 9 are expanded by the inflow hydraulic fluid to expand their volumes, and the bushes 6 and 8 are elastically deformed from the broken line state in FIG. 3 to the solid line state to push down the vehicle body side pivot point to the vehicle lower side.

That is, during driving, the suspension geometry changes from the solid line state in FIG. 2 to the broken line state, and the roll center height becomes low. In this way, when the roll center height becomes low, the load movement amount of the rear wheels is reduced by the above equation (2).

Due to the reduction of the load movement amount of the rear wheel, the wheel load on the turning inner wheel side is maintained at the time of acceleration turning, the idling of the inner wheel is prevented, the traction capacity is improved, and the rear wheel when power is applied. It is possible to prevent power oversteering that occurs due to a decrease in cornering force.

As described above, in the vehicle rear suspension device of the first embodiment, the radius rod 4, the front parallel link 2, and the front parallel link 2 are arranged in order to reduce the roll center height of the rear wheels due to the volume change due to the rear wheel input of the driving force. Since the communication pipe 12 that connects the first liquid chamber 11 and the second liquid chambers 7, 9 formed in each of the bushes 10, 6, 8 provided in the rear parallel link 3 is provided, the roll center height is reduced. Due to the action of reducing the load movement amount of the rear wheels due to the above, it is possible to prevent the steer characteristic change and the idling of the turning inner wheels during turning acceleration.

(Second Embodiment) First, the structure will be described.

FIG. 4 is a perspective view showing a double-wishbone type vehicle front suspension device of a second embodiment applied to a front-wheel drive vehicle.

In FIG. 4, an axle 21 (corresponding to an axle member) that rotatably supports a front wheel (not shown), which is a drive wheel, includes an L-shaped lower link 22 (corresponding to a first suspension member and a second suspension member) and It is swingably supported by the A-type upper link 23 with respect to the vehicle body. A tie rod 24 from the front wheel steering mechanism is connected to the axle 21.

The L-shaped lower link 22 is disposed below the axle, and a link bush 25 (corresponding to a second elastic body) that defines the roll center height is provided on the vehicle body support portion on the front side of the vehicle. A compression rod bush 26 (corresponding to a first elastic body) that is elastically deformed when a driving force is input is provided on the vehicle body rear side of the vehicle. A second liquid chamber 27 is formed in the link bush 25 at a lower position of the inner cylinder, and a first liquid chamber 28 is formed in the compression rod bush 26 at a vehicle outer position of the inner cylinder. There is.

The first liquid chamber 28 and the second liquid chamber 27 are connected by a communication pipe 29, and the inside thereof is filled with a working fluid.

Next, the operation will be described.

When the vehicle is accelerated by depressing the accelerator, when a driving force is applied from the front wheels, which are the driving wheels, toward the front of the vehicle through the axles 21, the L-shaped lower link 22 is moved forward about the link bush 25. The force to rotate acts.

The compression rod bush 26 is elastically deformed by the rotational force of the L-shaped lower link 22 as shown in FIG.
The first liquid chamber 28 of No. 6 is crushed and its volume is reduced, and the working fluid flows out from the first liquid chamber 28 to the communication pipe 29.

The working fluid that has flowed out flows into the second liquid chamber 27 of the link bush 25 through the communication pipe 29, and
The liquid chamber 27 is expanded by the inflow hydraulic fluid to expand its volume, the link bush 25 is elastically deformed from the broken line state in FIG. 6 to the solid line state, and the vehicle body side pivot point is pushed down to the vehicle lower side.

That is, during driving, the suspension geometry changes from the solid line state in FIG. 5 to the broken line state, and the roll center height becomes low. As described above, when the roll center height becomes low, the load movement amount of the front wheels is reduced by the above equation (1).

Due to the reduction in the load movement amount of the front wheels, the wheel load on the turning inner wheel side is maintained during acceleration turning, the inner wheel idling is prevented, the traction capability is improved, and the front cornering is applied when power is applied. It is possible to prevent the power drift out caused by the decrease in force.

As described above, in the vehicle front suspension device of the second embodiment, the roll center height of the front wheels is lowered by the volume change due to the input of the driving force to the front wheels.
Bushings 26, 25 provided on the L-shaped lower link 22
Since the communication pipe 29 that connects the first liquid chamber 28 and the second liquid chamber 27 formed in each of the above is provided, the steering wheel at the time of turning acceleration is reduced due to the action of reducing the load movement amount of the front wheels accompanying the decrease of the roll center height. It is possible to prevent characteristic changes and idling of the turning inner wheel.

Although the embodiments have been described above with reference to the drawings, the specific configuration is not limited to the embodiments, and modifications and additions within the scope of the present invention are included in the present invention. Be done.

For example, the application to the independent suspension device is not limited to the type shown in the embodiment, but may be applied to other types of independent suspension devices.

Further, the communication pipe does not directly communicate between the liquid chambers, but may indirectly communicate with each other through a free piston whose maximum displacement amount is regulated by a stopper to transmit the hydraulic pressure. Good.

[0044]

As described above, in the suspension device for a vehicle of the present invention, the suspension member is provided in order to reduce the roll center height of the drive wheel due to the volume change due to the drive wheel input of the drive force. Since the communication pipes that connect the first liquid chamber and the second liquid chamber, which are formed in the first elastic body and the second elastic body, respectively, are provided, it is possible to reduce the load movement amount of the drive wheel accompanying the decrease in the roll center height. Therefore, it is possible to obtain an effect that it is possible to prevent a change in steer characteristic at the time of turning acceleration and an idling of the turning inner wheel.

[Brief description of drawings]

FIG. 1 is a perspective view showing a vehicle rear suspension device of a first embodiment.

FIG. 2 is a schematic perspective view showing a state of a suspension geometry change at the time of shifting from normal running to driving in the apparatus of the first embodiment.

FIG. 3 is an operation explanatory view showing a deformed state of the bush at the time of shifting from normal traveling to driving in the apparatus of the first embodiment.

FIG. 4 is a perspective view showing the vehicle front suspension device of the first embodiment.

FIG. 5 is a schematic perspective view showing a state in which the suspension geometry changes at the time of shifting from normal running to driving in the apparatus of the second embodiment.

FIG. 6 is an operation explanatory view showing a deformed state of the bush at the time of shifting from normal traveling to driving in the second embodiment device.

FIG. 7 is a perspective view showing a conventional vehicle rear suspension device.

FIG. 8 is a diagram illustrating load movement during vehicle body roll.

[Explanation of symbols]

1 Axle (corresponding to an axle member) 2 Front parallel link (2nd suspension member) 3 Rear parallel link (2nd suspension member) 4 Radius rod (1st suspension member) 5 A type upper link 6 Front parallel link bush (2nd elasticity) Body) 7 2nd liquid chamber 8 Rear parallel link bush (2nd elastic body) 9 2nd liquid chamber 10 Radius rod bush (1st elastic body) 11 1st liquid chamber 12 Communication pipe

Claims (1)

[Claims] 1. An axle member that rotatably supports a drive wheel, a first suspension member that is connected to the axle member, and has a first elastic body that is elastically deformed by input of a drive wheel of a driving force, and the axle member. A second suspension member that is connected to the vehicle body supporting portion and has a second elastic body that defines a roll center height, and a first liquid chamber and a second liquid chamber that are formed in each of the first elastic body and the second elastic body. And a communication pipe that communicates with the first liquid chamber and the second liquid chamber in a pressure-transmittable manner so as to reduce the roll center height of the drive wheel due to a change in the volume of the drive force input to the drive wheel. Characteristic vehicle suspension device.