JP2000205327A - Liquid sealing bush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid sealing bush capable of reducing load noise greatly without impairing operability and stability. SOLUTION: A liquid chamber formed by an inner cylinder side member 3, an outer cylinder side member 2, and an outer elastic body 4 is partitioned into a first and second liquid chamber 5a, 5b side and a third and fourth liquid chamber 6a, 6b side by a first elastic body. Furthermore, both of these liquid chambers are partitioned into a first liquid chamber 5a, a second liquid chamber 5b, a third liquid chamber 6a, and a fourth liquid chamber 6b by a second elastic body 1 which has a groove part 8 formed at inner periphery of the outer cylinder side member 2 and a slight clearance and is fixed on the inner cylinder side member 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-filled bush attached to a suspension link.

[0002]

2. Description of the Related Art As a conventional liquid-filled bush, there is a technique described in JP-A-6-129460 and JP-A-7-280026. In the former example, a part of the elastic body welded to the outer cylinder side member corresponding to a part of the inner cylinder side member has a spherical shape in order to reduce the sliding force against the twisting direction displacement. Further, in the latter example, the provision of two liquid chambers allows the torsion bar to be easily displaced relative to the outer cylinder in the rotational direction, but not easily displaced in the direction perpendicular to the axis (the direction in which the liquid chambers exist). It has a structure.

[0003]

By reducing the torsional and torsional rigidity of the suspension bush, it is possible to reduce the link shaft direct input transmitted from the suspension link to the vehicle body during traveling. However, in the conventional technology, if the rigidity in the rotational direction of the torsional rigidity or torsional rigidity is reduced, the rigidity in the direction perpendicular to the axis is reduced, and the steering and stability characteristics are adversely affected. there were. Looking at the conventional example, see JP-A-6-12946.
In Japanese Patent Publication No. 0, the contact portions are made spherical to reduce the rigidity in the twisting direction. However, since the metal and the elastic body are in contact with each other, sliding friction occurs. Are considered to be displaced integrally. That is, in this conventional example, it is substantially difficult to reduce the torsional rigidity. JP-A-7-2800
In the conventional example disclosed in Japanese Patent Publication No. 26, since the rigidity in the left-right direction is determined by the expansion elasticity of the elastic body constituting the liquid chamber, when the value of the expansion elasticity is increased to increase the left-right rigidity, the torsional rigidity also increases. Will increase.

[0004] In the present invention, considering that road noise is mainly a problem during straight cruising and that the bush shaft stiffness in the direction of the axis is required mainly when steering and when a force acts on the bush, the inner cylinder is required. The purpose is to significantly reduce road noise without sacrificing maneuverability and stability by arranging the elastic body fixed to the side member with a slight gap in the groove provided in the outer cylinder side member. And

[0005]

In order to achieve the above object, an invention according to claim 1 of the present invention is a substantially cylindrical bush mainly used as an elastic coupling element between a suspension link and a vehicle body. A liquid chamber is formed by a cylinder-side member, an outer cylinder-side member, and an outer elastic body that couples them, and the interior of the liquid chamber is radially partitioned by a first elastic body. Is characterized in that the second elastic body fixed to the inner cylinder side member is provided with a slight gap so as to correspond to the outer cylinder side member.

According to a second aspect of the present invention, in the liquid sealing bush according to the first aspect, the second elastic body comes into contact with the outer cylinder side member at the time of a large input in a direction perpendicular to the bush axis, and the second elastic body is provided between the liquid chambers. By acting as a partition, movement of liquid between partitioned liquid chambers is prevented.

According to a third aspect of the present invention, in the liquid sealing bush according to the first or second aspect, a groove is formed in the outer cylinder side member in a circumferential direction, and the second cylinder is fixed to the inner cylinder side member. The outer peripheral portion of the elastic body has a shape substantially matching the shape of the groove.

According to a fourth aspect of the present invention, in the liquid sealing bush according to any one of the first to third aspects, the expansion elasticity of the second elastic body is the outer elastic body connecting the inner cylinder side member and the outer cylinder side member. It is characterized by being larger than the expansion elasticity.

According to a fifth aspect of the present invention, in the liquid sealing bush according to the third or fourth aspect, the cross-sectional shape of the outside of the groove coincides with a part of an arc centered on the center of the liquid sealing bush main body. Features.

[0010]

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

FIG. 1 is a view showing an application site of a liquid sealing bush according to an embodiment of the present invention. As shown by the arrows in the figure, the effect can be maximized if it is used for a portion that largely affects the steering and stability performance, such as camber rigidity, and has a large contribution to road noise input.

Next, the configuration of the liquid sealing bush according to the present embodiment will be described with reference to the sectional views of the liquid sealing bush shown in FIGS.

As shown in the figure, the outer cylinder side member 2 and the inner cylinder side member 3 are elastically connected by an outer elastic body 4, and a space formed by them is filled with a liquid. This liquid chamber is isolated by the first elastic body 7 into two liquid chambers, and there is no movement of liquid between the two liquid chambers. Further, these two liquid chambers are connected to each other by the second elastic body 1 fixed to the inner cylinder side member 3 so as to have two first liquid chambers 5a, second liquid chambers 5b, two third liquid chambers 6a,
It is divided into a fourth liquid chamber 6b.

The outer peripheral portion of the second elastic body 1 is installed so as to be opposed to the groove 8 provided on the inner peripheral surface of the outer cylinder side member 2 with a slight gap. Further, as shown in FIG. 2, a part of the cross-sectional shape of the groove 8 is an arc centered on the center point of the liquid sealing bush.

When a force in the axial direction is applied to the liquid sealing bush, the first liquid chamber 5a, the second liquid chamber 5b, and the third liquid chamber 6
a, a pressure difference is generated between the fourth liquid chamber 6b and the outer peripheral portion of the second elastic body 1 is pressed against the groove 8 provided in the outer cylinder side member 2 to be in a state of being covered, and the liquid You will not be able to move.

Next, the operation of the liquid sealing bush according to this embodiment will be described.

As shown in FIG. 5, during traveling, the tire portion vibrates due to input from the road surface, and the vibration is input to the vehicle body via the suspension link. At this time, assuming that the ball joint portion is free to rotate, as shown in the graph of FIG. 6, the input level to the vehicle body in the direction (z direction) perpendicular to the link axis of the suspension is the torsional rigidity (kt) of the bush.
Lowers the lower. This is the same for the twisting direction. However, in the conventional bush structure, if the rigidity in the twisting and twisting directions is reduced, the rigidity in the direction perpendicular to the axis (x direction) required for steering and stability is reduced.

2 to 4, a description will be given of a mechanism for achieving both high rigidity in the direction perpendicular to the bush axis and low rigidity in the twisting and twisting directions in the liquid sealing bush according to the present embodiment.

During straight running, since a large force does not act in the direction perpendicular to the bush axis, the second elastic body 1 rotates the groove 8 of the outer cylinder side member 2 in the torsion direction without resistance by helping the lubricating action of the liquid. can do. At this time, only the outer elastic body 4 acts as the torsional rigidity, but since the outer elastic body 4 is set to have a lower rigidity than the second elastic body 1, the torsional rigidity is also small. Become. Also, in the twisting direction, since the contact surfaces of the second elastic body 1 and the outer cylinder side member 2 are substantially on the same circle, the gap can be smoothly displaced relative to each other.

At the time of steering, when the force in the direction perpendicular to the bush axis (the force in the X direction shown in FIG. 5) is input to the bush, the first force is applied.
The liquid chamber 5a and the second liquid chamber 5b are separated by the second elastic body 1 so that the liquid cannot move. The higher the pressure of the second liquid chamber 5b, the more the outer peripheral portion of the second elastic body 1 becomes the groove 8 of the outer cylinder side member 2.
And the degree of sealing increases. Third liquid chamber 6
a, in the fourth liquid chamber 6b, the pressure in the fourth liquid chamber 6b becomes the lowest, contrary to the first liquid chamber 5a and the second liquid chamber 5b.

When a force acts on the bush in which the liquid is sealed in a direction to change the volume of the liquid chamber, the rigidity in this direction is the rigidity (supporting rigidity) of the rubber alone with the liquid removed and the sealing of the liquid. In this case, the liquid is expressed by the sum of the rigidity (expanded elasticity) of the rubber in the direction in which the liquid tries to spread the rubber forming the liquid chamber. When the contribution of the expansion elasticity of the body 1 increases, a large axial rigidity is generated from that moment. Further, since the large pressure does not act on the first liquid chamber 5a and the third liquid chamber 6a due to the partitioning action of the second elastic body 1, the rigidity of the outer elastic body 4 which has a large influence on the torsional and twisting rigidity is reduced. Can be set low.

As described above, the cornering force generated by the tire is received with high bush stiffness when the vehicle is about to turn, such as during steering, and when the vehicle is going straight, the torsional stiffness and the twisting stiffness can be greatly reduced. Road noise input from the suspension to the vehicle body can be reduced while maintaining performance.

[0023]

As described above, according to the liquid-filled bush of the present invention, the twisting and twisting rigidity can be reduced without impairing the steering / stability performance, so that the road noise can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing an application site of a liquid sealing bush according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the liquid sealing bush according to the embodiment;

FIG. 3 is a sectional view taken along line AA of FIG. 2;

FIG. 4 is a sectional view taken along line BB of FIG. 3;

FIG. 5 is a diagram illustrating an operation of the liquid sealing bush according to the embodiment.

FIG. 6 is a diagram illustrating the operation of the liquid sealing bush according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 2nd elastic body 2 outer cylinder side member 3 inner cylinder side member 4 outer elastic body 5a 1st liquid chamber 5b 2nd liquid chamber 6a 3rd liquid chamber 6b 4th liquid chamber 7 1st elastic body 8 groove part

Claims (5)

[Claims] 1. A substantially cylindrical bush mainly used as an elastic coupling element between a suspension link and a vehicle body, wherein a liquid chamber is formed by an inner cylinder-side member, an outer cylinder-side member, and an outer elastic body that connects them. The liquid chamber is formed and partitioned in the radial direction by a first elastic body. In each of the partitioned liquid chambers, the second elastic body fixed to the inner cylinder side member has a slight gap. And a liquid-encapsulated bush, which is provided so as to correspond to the outer cylinder side member. And a second elastic body that comes into contact with the outer cylinder-side member at the time of a large input in a direction perpendicular to the bush axis and acts as a partition between the liquid chambers, so that the liquid between the partitioned liquid chambers is removed. The liquid-filled bush according to claim 1, wherein movement is prevented. 3. A groove is formed in the outer cylinder-side member in a circumferential direction, and an outer peripheral portion of the second elastic body fixed to the inner cylinder-side member has a shape substantially matching the shape of the groove. 3. The liquid-filled bush according to claim 1, wherein the liquid-filled bush is formed. 4. The liquid according to claim 1, wherein an expansion elasticity of the second elastic body is larger than an expansion elasticity of an outer elastic body connecting the inner cylinder side member and the outer cylinder side member. Enclosed bush. 5. The liquid sealing bush according to claim 3, wherein a cross-sectional shape of the outside of the groove matches a part of an arc centered on a center of the liquid sealing bush main body.