JPH06316211A - Suspension device for vehicle - Google Patents

Abstract

PURPOSE:To provide a vehicle suspension device which can compatibly achieve a good comfortableness at the time of getting over a step or the like and a good maneuverability or sense of steering at the time of controlled driving etc. CONSTITUTION:The fore-and-aft supporting stiffnesses of an L-shaped lower suspension member) and an L-shaped upper link 4 (upper suspension member) are set low, and first liquid chamber 8 and second liquid chamber 11 are formed inside of a lower resilient body 7 and an upper resilient body 10 which are installed in the car body supporting parts of the two links 3, 4 and are put in communication through a communication pipe 12 so that Point (b) is displaced, when Point (a) as a supporting point to specify the caster is displaced in the direction to behind the vehicle, in the same direction as displacement of Point (a).

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 which is applied to steered wheels.

[0002]

2. Description of the Related Art Conventionally, as a vehicle suspension device, for example, one shown in FIG. 8 has been known (HON
DA Service Manual Chassis Maintenance Accord / Vigor, 8
5-6).

According to the above-mentioned conventional source, the axle 02 for rotatably supporting the wheel 01 is a point a and an upper suspension link of a lower suspension link 03 arranged at a lower position and an upper position of an axle to define a caster. It is possible to swing up and down by the point b of 04, and
It is supported so that it can be steered.

Further, the lower suspension link 03
Is swingably attached to the vehicle body at points c and d, and the rigidity of the elastic body used at point c is adjusted so that the rigidity in the front-rear direction at point a can be set to be appropriately low.

[0005]

However, in the above-mentioned conventional vehicle suspension device, the axle 0 is not used.
Since the rigidity in the front-rear direction at the points a and b, which are the two supporting points, is independent and is not coupled to each other, there are the following problems.

When the longitudinal rigidity at points a and b is set low in order to improve vibration characteristics when riding over a step, etc., the steering axis changes in angle (caster change) due to input of longitudinal force, and The trail, which is the horizontal distance of the intersection between the axle and the road surface of the wheel center axle, changes, and the maneuverability or steering feel deteriorates. That is, as shown in FIG. 9, the steering axis L represented by a straight line connecting the points a and b when the longitudinal force is not input is, for example, as shown in FIG. Along with this, points a and b move to points a ′ and b ′, and this movement causes the steered axis to become L ′.

On the other hand, if the front and rear rigidity at points a and b is set high in order to maintain maneuverability or steering feeling during braking or the like and the change in casters is suppressed to a small value, the vibration characteristics when overcoming a step are deteriorated. .

The present invention has been made in view of the above problems, and in a vehicle suspension device, achieves a good ride comfort when climbing over a step or the like and good maneuverability during braking / driving or the like. The challenge is to achieve both steering feeling and achievement.

[0009]

In order to solve the above-mentioned problems, in a vehicle suspension device of the present invention, a lower elastic member and an upper elastic member provided in the vehicle body supporting portions of the lower suspension member and the upper suspension member are provided with a first elastic member. The first liquid chamber and the second liquid chamber are formed, and when one of the support points defining the caster is displaced in one direction in the vehicle front-rear direction, the other point is displaced by the communication pipe so that the other point is displaced in the same direction. Communicated during pressure.

That is, an axle member that rotatably supports a wheel, and an axle member that is connected to the axle member and is located at a lower position and an upper position of an axle to define a caster and has a low support rigidity in the front-rear direction. A lower suspension member and an upper suspension member, a lower elastic body and an upper elastic body provided on a vehicle body supporting portion of the lower suspension member and the upper suspension member, and a braking force formed on the lower elastic body and the upper elastic body, respectively. Alternatively, when one of the first liquid chamber and the second liquid chamber whose internal volume changes when the driving force is input to the wheel and one of the support points is displaced in one direction of the vehicle front-rear direction, the other point is displaced in the same direction. It is provided with a communication pipe that connects the first liquid chamber and the second liquid chamber to each other at the time of hydraulic pressure.

[0011]

When the longitudinal force that fluctuates on the wheels is input when riding over a step or the like, the elasticity of the lower suspension member and the upper suspension member connected to the axle member for rotatably supporting the wheels is provided on the vehicle body side support portion. Due to the deformation of the body, the input longitudinal fluctuation force is effectively reduced.

Further, when a forward force or a backward force is input to the wheel during braking / driving, and one of the supporting points is displaced in one direction of the vehicle front-rear direction, the lower elastic force is accompanied by the displacement of the one supporting point. The corresponding one of the first liquid chamber and the second liquid chamber formed inside the body or the upper elastic body contracts, and the hydraulic fluid that has flowed out passes through the communication pipe and flows into the other liquid chamber. And expand the other liquid chamber. Due to this liquid chamber contraction and liquid chamber expansion action, both support points are displaced in the same direction, and the steering axis connecting both support points moves in parallel.Before and after the longitudinal force input, the angle of the steering axis is changed. In other words, changes in casters are suppressed.

[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 vehicle front suspension device according to a first embodiment of the present invention.

In FIG. 1, an axle 2 (corresponding to an axle member) for rotatably supporting a wheel (not shown) is an L-shaped lower link 3 arranged at a lower position and an upper position of an axle to define a caster. The point a (corresponding to the lower suspension member) and the point b of the L-shaped upper link 4 (corresponding to the upper suspension member) are swingably supported in the vertical direction and steerable. The support rigidity in the vehicle front-rear direction at points a and b is set low. A tie rod 5 from the front wheel steering mechanism is connected to the axle 2.

The L-shaped lower link 3 has a lower elastic body 6,
A first liquid chamber 8 is formed inside the vehicle inside a lower elastic body 7 on the vehicle rear side so as to be swingably supported by 7.

The L-shaped upper link 4 is swingably supported by the vehicle body by upper elastic bodies 9 and 10, and a second liquid chamber 11 is provided inside the vehicle outside of the upper elastic body 10 on the vehicle rear side. Has been formed.

The first liquid chamber 8 and the second liquid chamber 11 are communicated with each other through a communication pipe 12, and both liquid chambers 8 and 1 are connected.
The working fluid is filled inside the communication pipe 1 and the communication pipe 12.

Next, the operation will be described.

(A) When inputting front-rear fluctuation force When a front-rear force that fluctuates on a wheel is input when riding over a step or when bouncing, a connection point between the axle 2 and the L-type lower link 3 and the L-type upper link 4 Since the support rigidity in the front-rear direction is set low at the points a and b, the input longitudinal fluctuation force is effectively reduced.

As a result, the transmission of the longitudinal fluctuation force applied to the wheels to the vehicle body is suppressed to a small level, and a good riding comfort can be achieved.

(B) During braking During constant-speed straight traveling, turning, etc., and when the longitudinal force input from the wheel to the point a through the axle 2 is small, L
Rotation of the lower lower link 3 about the point f of the lower elastic body 6 is small, and the volume of the first liquid chamber 8 formed inside the lower elastic body 7 supported by the vehicle body of the L-shaped lower link 3 is substantially unchanged. As shown in FIG. 2, in both liquid chambers 8 and 11, the working fluid does not substantially flow through the communication pipe 12. It should be noted that the vertical force input from the wheel to the point a via the axle 2 escapes due to the swing of the L-shaped lower link 3 and does not become a force that causes a change in the volume of the first liquid chamber 8, and the lateral force is The force is received by the lower elastic body 6 that exists substantially on the extension line of the vehicle width direction at the point a, and does not serve as a force that causes the volume change of the first liquid chamber 8.

When the vehicle rearward force is input from the wheel to the point a via the axle 2 during braking from the normal state, as shown in FIG. 4, the L-shaped lower link 3 is moved to the lower elastic body 6 as shown in FIG. Is rotated about the point f, the point a is displaced to the rear a'point, and the point e is displaced to the inner side e'point. With the displacement from the point e to the point e ′, as shown in FIG. 3, the first liquid chamber 8 formed inside the lower elastic body 7 is pushed toward the inside of the vehicle to be contracted, and the first liquid is discharged. The hydraulic fluid flowing out of the chamber 8 passes through the communication pipe 12 and flows into the second liquid chamber 11 of the upper elastic body 10 to expand the second liquid chamber 11.

Due to the expansion of the second liquid chamber 11, as shown in FIG. 4, g of the upper elastic body 10 of the L-shaped upper link 4 is increased.
The point rotates about the h point, the g point is displaced to the g ′ point inside the vehicle body, and the b point is displaced to the rear b ′ point.

By this action, the steered shaft L of the wheel passing through the points a and b moves in parallel to the rear of the vehicle, and the steered shaft L and the rear steered shaft L before the rearward force of the vehicle due to braking is input. The angle of the steered shaft L'of, that is, the change of the caster is suppressed.

As a result, good maneuverability or steering feeling can be obtained without deteriorating the maneuverability or steering feeling due to caster change.

Next, the effect will be described.

(1) In the vehicle front suspension device, the L-shaped lower link 3 and L for defining casters
The supporting rigidity in the front-rear direction of the mold upper link 4 is set low, and the first liquid chamber 8 and the second liquid 8 are provided inside the lower elastic body 7 and the upper elastic body 10 provided in the vehicle body supporting portions of both links 3, 4. A support point a that forms the chamber 11 and defines the caster,
Since the first liquid chamber 8 and the second liquid chamber 11 are communicated with each other by the communication pipe 12 so that when one a point of the b points is displaced in the rearward direction of the vehicle, the other b point is displaced in the same direction, so that the step can be overcome. At the same time, it is possible to achieve both good riding comfort at times and good maneuverability or steering feeling at the time of braking.

(2) Since the invention is applied to the front wheels, which are the steered wheels, it is possible to suppress abnormal vibrations such as shimmy due to the damping force generated by the movement of the hydraulic fluid accompanying the front-back movement of the axle 2.

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

FIG. 5 is a perspective view showing a McPherson strut type vehicle front suspension device of the second embodiment.

In FIG. 5, an axle 22 (corresponding to an axle member) for rotatably supporting a wheel (not shown) is a lower link 23 (lower portion) which is arranged at a lower position and an upper position of an axle to define a caster. It is supported so as to be swingable in the vertical direction and steerable by point a of the suspension member) and point i of the shock absorber 24 (corresponding to the upper suspension member). And a
The support rigidity in the vehicle front-rear direction at the points i and i is set low. A tie rod 25 from the front wheel steering mechanism is connected to the axle 22.

The lower link 3 is composed of a vertical link portion 23a and a horizontal link portion 23b, and the respective link portions 23a and 23b are swingably supported by the vehicle body by the lower elastic bodies 26 and 27, and the vertical link is formed. A first liquid chamber 28 is formed inside the vehicle of the lower elastic body 26 on the side of the portion 23a.

The shock absorber 24 is swingably supported by the vehicle body by an upper elastic body 29, and a second liquid chamber 30 is formed inside the upper elastic body 29 on the vehicle front side.

Then, the first liquid chamber 28 and the second liquid chamber 30
Are communicated with each other via a communication pipe 31, and both liquid chambers 2
A hydraulic fluid is filled inside the communication pipes 8 and 30.

Next, the operation will be described.

(A) When inputting front-rear fluctuation force When a front-rear force that fluctuates on a wheel is input when a vehicle climbs over a step or bounces, point a, which is a connection point of the axle 22, the lower link 23, and the shock absorber 24 And i
At this point, since the supporting rigidity in the front-rear direction is set low, the input front-rear fluctuation force is effectively reduced.

As a result, the transmission of the longitudinal fluctuation force applied to the wheels to the vehicle body is suppressed to a small level, and a good riding comfort can be achieved.

(B) During braking During constant-speed straight traveling, turning, etc., and when the longitudinal force input from the wheels to the point a through the axle 22 is small,
The elastic deformation of the lower elastic body 28 of the lower link 23 that receives the longitudinal force is small, and as shown in FIG. 6, the working fluid is hardly circulated through the communication pipe 31 in both the fluid chambers 28 and 30. Become.

The vertical force input from the wheel to the point a via the axle 22 escapes due to the swing of the vertical link portion 23a and does not become a force that causes a change in the volume of the first liquid chamber 28.
In addition, the lateral force is received by the lower elastic body 27 existing substantially on the line extending in the vehicle width direction at the point a, and does not become a force that causes a change in the volume of the first liquid chamber 28.

When a vehicle rearward force is input from the wheel to the point a through the axle 22 during braking from the normal state described above, the lower link 23 rotates about the point k of the lower elastic body 27 as a center. , Points a and j are displaced rearward. With the displacement of the point j, as shown in FIG. 7, the first liquid chamber 28 formed inside the lower elastic body 26 is pushed rearward of the vehicle to be contracted, and flows out of the first liquid chamber 28. The hydraulic fluid passes through the communication pipe 31 and flows into the second liquid chamber 30 of the upper elastic body 29 to expand the second liquid chamber 30. This second
Due to the expansion of the liquid chamber 30, the point i of the upper elastic body 29 of the shock absorber 24 is displaced rearward of the vehicle.

By this action, the steered shafts of the wheels passing through the points a and i move in parallel to the rear of the vehicle, and the steered shafts before and after the rearward force of the vehicle due to braking is input. The change of the angle of the rudder axis, that is, the caster is suppressed.

As a result, good maneuverability or steering feeling can be obtained without deteriorating maneuverability or steering feeling due to caster change.

Next, the effect will be described.

(1) In the vehicle front suspension device, the supporting rigidity of the lower link 23 and the shock absorber 24 that define the casters in the front-rear direction is set low, and the suspension members 23 and 24 are provided on the vehicle body supporting portions. A first liquid chamber 28 and a second liquid chamber 30 are formed inside the lower elastic body 26 and the upper elastic body 29, and one of the supporting points a and i defining the caster, a point a, is displaced rearward of the vehicle. Since the first liquid chamber 28 and the second liquid chamber 30 are communicated with each other by the communication pipe 31 so that the other point i is displaced in the same direction at the time of running, it is possible to achieve a good ride comfort when climbing over a step and at the time of braking. It is possible to achieve both good maneuverability and steering feeling.

(2) Since the invention is applied to the front wheels, which are the steered wheels, it is possible to suppress abnormal vibrations such as shimmy due to the damping force generated by the movement of the hydraulic fluid accompanying the forward and backward movement of the axle 22.

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, in the embodiment, the example of application to the front suspension device having steered wheels is shown, but it may be applied to the rear suspension device in a four-wheel steering vehicle or the like.

In the embodiment, the example in which the caster change is suppressed during braking has been described. However, by changing the arrangements of the first liquid chamber and the second liquid chamber so as to communicate with each other, the caster changes during driving such as starting or accelerating. Can be suppressed.

Further, the communication pipe does not directly communicate between the liquid chambers but indirectly communicates through a free piston whose maximum displacement amount is regulated by a stopper to transmit the hydraulic pressure. May be.

[0052]

As described above, according to the present invention, in the vehicular suspension device, the lower elastic member and the upper elastic member provided in the vehicle body supporting portions of the lower suspension member and the upper suspension member are provided with the first and second elastic members. The first liquid chamber and the second liquid chamber are formed, and when one of the support points that define the caster is displaced in one direction in the vehicle front-rear direction, the two liquid chambers are pressed by the communication pipe so that the other point is displaced in the same direction. Since the communication is performed in a communicable manner, it is possible to achieve both good ride comfort when climbing over a step or the like and good maneuverability or steering feel when braking / driving.

[Brief description of drawings]

FIG. 1 is a perspective view showing a vehicle front suspension device according to a first embodiment of the present invention.

FIG. 2 is an operation explanatory view showing a state of a lower elastic body and an upper elastic body at a normal time when the longitudinal force is not input in the device of the first embodiment.

FIG. 3 is an operation explanatory view showing states of a lower elastic body and an upper elastic body at the time of braking in the device of the first embodiment.

FIG. 4 is a perspective view showing displacement of each support point when the normal state is shifted to the braking state.

FIG. 5 is a perspective view showing a vehicle front suspension device according to a second embodiment of the present invention.

FIG. 6 is an operation explanatory view showing a state of a lower elastic body and an upper elastic body at a normal time when the longitudinal force is not input in the device of the second embodiment.

FIG. 7 is an operation explanatory view showing the states of the lower elastic body and the upper elastic body during braking in the device of the second embodiment.

FIG. 8 is a perspective view showing a conventional vehicle front suspension device.

FIG. 9 is a view showing a caster in a normal state in a conventional device.

FIG. 10 is a diagram showing changes in casters during braking in the conventional device.

[Explanation of symbols]

 2 Axle (axle member) 3 L-type lower link (lower suspension member) 4 L-type upper link (upper suspension member) 5 Tie rod 6,7 Lower elastic body 8 First liquid chamber 9,10 Upper elastic body 11 Second liquid chamber 12 communication tubes

Claims (1)

[Claims] 1. An axle member that rotatably supports a wheel, and a lower suspension member and an upper suspension member that are connected to the axle member and that have respective support points at a lower position and an upper position of an axle to define a caster. A lower elastic body and an upper elastic body provided on the vehicle body supporting portions of the lower suspension member and the upper suspension member, respectively, and an internal volume formed when the braking force or the driving force is input to the wheel. A first liquid chamber and a second liquid chamber, and when one of the support points is displaced in one direction of the vehicle front-rear direction, the other of the support points is displaced in the same direction. A suspension device for a vehicle, comprising: a communication pipe that communicates with each other so that pressure can be transmitted.