JPH01238731A - Bush having fluid therein - Google Patents

Abstract

PURPOSE:To restrain relative displacement between the axial center and right angle directions so as to improve seal and durability properties by housing an independent stopper member in a fluid chamber as well as monolithically arranging a metal sleeve at the outer peripheral face of a resilient member. CONSTITUTION:A rubber sleeve 8 has a ring made of two thin metal cylinders, at the outer peripheral face at both ends. In a fluid chamber 16, a metal stopper member 26 is housed in a state that it is not fixed or suspended by any one of an outer cylindrical metal member 6, an inner cylindrical metal member 4, and a rubber sleeve 8. When a large oscillation load is generated between the members 4, 6, and large displacement is generated between them in the direction vertical to the axial center, and then the rubber sleeve 8 is greatly deformed. As a result, the stopper face of the stopper members 26 abuts against rubber layers 14, 24 so as to restrain the deformation.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to an improved structure of a striped fluid-filled bushing,
A fluid-filled product that has a stopper function that restricts the amount of deformation of the elastic body especially when a large load is input, increasing its durability, ensuring fluid sealing performance, and improving assembly workability and mass production. It concerns the structure of Bu-Nshu.

(Prior art and its problems) Various arms, ports, and ends have been used to suspend differential gears, wheels, etc. to the body of an automobile.

A suspension member such as a ring is attached so as to be able to swing in each direction, and suspension bushings are generally incorporated into the pivot portions at both ends of the suspension member for the purpose of damping vibrations and the like.

Further, as a bushing for the same purpose, an engine mount is also used which is interposed between the engine and the vehicle body to suppress the transmission of vibrations.

By the way, such suspension bushings, bushings as anti-vibration supports for engine mounts, etc. generally consist of an inner cylinder member into which a predetermined pivot shaft is inserted for vehicle suspension, and a predetermined distance outside the inner cylinder member. It has a structure in which a rubber sleeve is inserted between the outer cylindrical member and the outer cylindrical member placed apart from each other, and vibrations are damped by deformation of the rubber sleeve. So-called fluid-filled bushings have been used, which have a structure in which a fluid chamber containing a predetermined incompressible fluid is formed in a rubber sleeve disposed between the rubber sleeves. It is attracting attention because it can advantageously provide anti-vibration properties that cannot be obtained with sleeves alone.

However, in the conventional fluid-filled bushing structure, the fluid chamber is formed by press-fitting the rubber sleeve into the outer cylinder member, which causes the problem that the fluid chamber deforms and becomes unstable in shape. In addition, there is a problem in that it is necessary to bond the outer cylinder member and the rubber sleeve after the press-fitting operation, and in order to fill the fluid chamber with fluid and take out the air from the fluid chamber, After the rubber sleeve is press-fitted, as described in Japanese Patent Publication No. 4B-36151, the troublesome work of using a syringe needle is required, which significantly reduces the workability of assembling the bushing, leading to the problem of increased costs. There it was. Furthermore, in such conventional composite bush structures, there is considerable difficulty in applying pre-compression to the rubber sleeve in order to improve durability.

Therefore, one way to solve these problems is to integrally fix a suitable rigid member to the outer peripheral surface of the rubber sleeve and press fit it into the outer cylindrical member in an incompressible fluid. As a result, the conventional post-adhesive process can be eliminated, and the pocket can be filled with fluid at the same time as the press-fitting operation, resulting in improved assembly workability. It will be done. However, such a structure in which a rigid member is interposed between the rubber sleeve and the outer cylinder member has a problem with the sealing performance between the rigid member and the outer cylinder fitting, and it is difficult to know what kind of seal structure to adopt. The big question that remained was whether to do so. In addition, as for the seal between the two member pipes,
In general, since 0 rings etc. are often used,
It is conceivable to install such an O-ring between the rigid member and the outer cylindrical member to provide a seal between these two members, but the rigid O-ring is formed relatively thin in order to apply pre-compression to the rubber sleeve. It is extremely difficult to attach such an O-ring to a member, and when such an O-ring is present on the outer peripheral surface of a rigid member, there are problems such as that the pre-compression operation itself becomes difficult. They also place orders.

Furthermore, in the fluid-filled bushing of the conventional structure, there is no way to prevent excessive displacement between the inner cylinder member and the outer cylinder member, or in other words, to prevent excessive displacement of the rubber sleeve inserted between the two members. The problem is that the rubber sleeve undergoes large deformation when a large load is applied to it, and that the rubber sleeve is damaged and its durability deteriorates due to repeated exposure to such large deformation. It also contained within it.

The present invention has been made against the background of the above-mentioned circumstances, and its purpose is to advantageously pre-compress the elastic body while ensuring good sealing performance of the fluid chamber. It is possible to realize this method, and its assembly workability can be improved, and problematic deformation of an elastic body such as a rubber sleeve when a large load is input can be effectively controlled, and its durability can be advantageously improved. An object of the present invention is to provide a fluid-filled bushing that obtains a fluid-filled bushing.

(Solution Means) In order to achieve the above object, in the present invention, an outer cylinder member is arranged outside the inner cylinder member at a predetermined distance, and the inner cylinder member and the outer cylinder member are connected. An elastic body is interposed between them to connect them, a recess is provided in the elastic member, and the opening of the recess is closed by the outer cylinder member, whereby a predetermined incompressible fluid can be In a fluid-filled bushing formed with an enclosed fluid chamber, a metal sleeve is integrally disposed on the outer circumferential surface of the elastic body so as not to cover the opening of the recess, and the inner circumference of the outer cylinder member is A sealing rubber layer of a predetermined thickness is integrally provided on the surface so that the opening of the recess is closed when the outer cylinder member is fitted onto the metal sleeve, and at least one of the fluid chambers is sealed. An independent stopper member that is not fixed is housed in the chamber, and the contact of the stopper member with the inner surface of the fluid chamber prevents excessive relative displacement in the direction perpendicular to the axes of the inner cylinder member and the outer cylinder member. It is characterized by the fact that it suppresses the

(Operation/Effect) That is, according to the present invention, an effective seal can be achieved between the seal rubber layer formed on the inner surface of the outer cylinder member and the metal sleeve arranged on the outer peripheral surface of the elastic body. Therefore, there is no need to provide any sealing means on the outer circumferential surface of such a metal sleeve, and moreover, effective precompression can be applied to the elastic body through the metal sleeve. Preliminary compression operations can now be performed easily. Furthermore, even when filling a fluid chamber with a predetermined incompressible fluid, the elastic body with the metal sleeve is fitted into the outer cylindrical member with a sealing rubber layer on the inner circumferential surface in the crimping fluid. Because you just have to insert it,
The operation is easy and reliable, and the ease of assembling the bushing is significantly improved.In addition, by providing a sealing rubber layer over the entire inner surface of the outer cylinder member, the outer cylinder member This prevents the fluid from coming into direct contact with the fluid contained in the fluid chamber, thereby effectively preventing corrosion of the outer cylinder member due to the fluid.

Further, according to the present invention, even if a large load is applied, the elastic body will not be deformed by more than a predetermined amount due to the restriction by the stopper member, and therefore damage caused by such large deformation of the elastic body will not occur. can be effectively suppressed, and its durability can be significantly improved.

Moreover, such a stopper member is not fixed,
Since they are placed in a suspended state within the fluid chamber, the durability of the elastic body that forms the inner wall of the fluid chamber may be affected when a relative torsional load occurs between the inner cylinder member and the outer cylinder member. It is effective in improving sexual performance. That is, assuming that the stopper member is fixed to the inner cylinder member, for example, when twisting occurs between the inner cylinder member and the outer cylinder member, the stopper member is simultaneously twisted and the elastic body portion in the twisting direction In other words, the inner wall portions on both sides of the fluid chamber are repeatedly pressed, which deteriorates the torsional durability of the elastic body portion, whereas the stopper member is independent and is not fixed to either side, so that Even if twisting occurs between the inner cylinder and the outer cylinder, the stopper member does not substantially move, and therefore does not press against the side wall of the fluid chamber, thus improving the durability of the side wall. It was decided to do so.

(Examples) Hereinafter, in order to clarify the present invention more specifically, examples of the present invention will be described in detail based on the drawings.

In FIGS. 1 and 2, 2 is a suspension bushing which is an embodiment of the present invention.

This bushing 2 has a relatively thick and cylindrical inner tube fitting 4 on its innermost side, and a pair of inner tube fittings 4, which correspond to inner tube members, are fixed to the vehicle body, axle housing, etc. The pivot shaft supported by the bracket will pass through it. And, on the outside of this inner cylinder metal fitting 4,
Cylindrical outer tube fittings 6 as outer tube members are arranged concentrically with a predetermined distance apart, and the outer tube fittings 6 and the inner tube fittings 4
An annular rubber sleeve 8 is interposed between the two and functions as an elastic body.

The rubber sleeve 8 has two symmetrical recesses 10 extending in the circumferential direction at corresponding positions on its outer circumferential surface, and the rubber sleeve 8 is provided with two symmetrical recesses lO extending in the circumferential direction at corresponding positions on the outer circumferential surface thereof, and the rubber sleeve 8 is arranged so as to sandwich the openings of the recesses 10.
Rings 12 each consisting of two short relatively thin metal cylinders are provided on both ends of the outer circumferential surface in the axial direction. On the other hand, on the inner surface of the outer cylinder fitting 6, a rubber layer 14 of a predetermined thickness made of rubber as an elastic material is formed over almost the entire inner surface.

Then, by covering the opening of the recess 10 of the rubber sleeve 8 with the outer cylindrical metal fitting 6 having the rubber layer 14 on the inner surface, separate fluid chambers 16 and 16 are formed, and the fluid chambers thus formed are 16, for example, water, alkylene glycol, polyalkylene glycol 6
Incompressible fluids such as silicone oil and low molecular weight polymers are each enclosed. Further, the rubber layer 14 on the inner surface of the outer cylinder fitting 16 is in close contact with the rings 12 disposed on the outer circumferential surface of the rubber sleeve 8 to form a liquid-tight space between them, thereby sealing the fluid chamber 16. It is designed to prevent incompressible fluid from leaking to the outside.

The two fluid chambers 16 are communicated with each other by an orifice. That is, an annular groove 18 is provided on the outer peripheral surface of the axially central portion of the inner cylinder fitting 4, and the ring body 20 is press-fitted into the outer peripheral surface of the inner cylinder fitting 4 so as to cover this annular groove 18. , an annular liquid passage is formed by the annular groove 18 and the inner circumferential surface of the ring body 20;
Further, a communication hole 22 is formed in the thickness direction of the ring body 20 to communicate the liquid passage (18) with each fluid chamber 16,
In this embodiment, the two fluid chambers 16 are communicated with each other by the liquid passage (18) and the orifice formed by the communication hole 22.

The ring body 20 includes, in its circumferential direction, alternately a portion surrounded by the rubber sleeve 8 and a portion located within the fluid chamber 16 and forming the bottom wall surface of the fluid chamber 16. The outer circumferential surface of the ring body, except for the opening of the communication hole 22, is covered with a rubber layer 24 continuous with the rubber sleeve 8. Then, this rubber layer 24 and the rubber layer 14 of the outer cylinder metal fitting 6 are located opposite to each other.

As is clear from FIG. 2, the walls of the fluid chambers 16 are parallel to each other in the axial direction of the rubber sleeve 8, but as shown in FIG.
Its walls are not parallel in the circumferential direction. That is, each of the fluid chambers 16 is formed in such a shape that the distance between the wall surfaces in the circumferential direction of the rubber sleeve 8 gradually decreases from the outer cylinder fitting 6 side to the inner cylinder fitting 4 side. Both wall surfaces are formed along the radial direction of the sleeve 8.

In such a fluid chamber 16, a metal stopper member 2 is provided.
6 is the outer cylinder metal fitting 6. They are not fixed to either the inner cylindrical metal fitting 4 or the rubber sleeve 8, and are housed in a so-called dangling state. In the axial direction of the outer cylindrical fitting 6, this stopper member 26 has a cross-sectional shape parallel to the axis of the outer cylindrical fitting 6, and is positioned at a predetermined interval between mutually parallel wall surfaces of the fluid chamber 16. However, in the circumferential direction of the outer cylindrical metal fitting 6, it has a curved shape corresponding to its inner circumferential surface, particularly an arcuate shape in this case. The length of the stopper member 26 in the arcuate direction is longer than the distance between the walls of the fluid chamber 16 on the inner cylindrical fitting 4 side, but is slightly shorter than the distance between the walls on the outer cylindrical fitting 6 side. Therefore, the stop member 26 has both ends in the arcuate direction in contact with both inclined wall surfaces of the fluid chamber 16, so that
In a normal state, it is located on the side of the outer cylinder metal fitting 6, and although it is not fixed, the opening of the communication hole 22 is prevented from being blocked.

Incidentally, such a suspension bushing 2 is manufactured, for example, according to the following process.

First, the ring body 20 is press-fitted into the outer periphery of the inner cylindrical metal fitting 4, and the ring 12, which is made up of two short metal tubes, are set concentrically in a predetermined mold, and the gap between them is set concentrically. By injecting a rubber material and vulcanization molding, the inner cylindrical fitting 4 and ring 12 are vulcanized and bonded, and the rubber sleeve 8 is vulcanized and molded at the same time. At that time, ring body 2
Each of the communication holes 22 of No. 0 is covered with a predetermined cap to prevent rubber material from entering. Then, simultaneously with the vulcanization molding of the rubber sleeve 8, the two recesses 10 are formed so as to open on the outer peripheral surface of the rubber sleeve 8.

Then, by reducing the diameter of the ring 12 located on the outer peripheral surface of the bush 2 assembly formed in this way to a predetermined outer diameter by a normal drawing operation, etc., the rubber sleeve 8 is Pre-compression is applied from the outside, thereby improving the durability of the rubber sleeve 8.

On the other hand, a rubber layer 14 of a predetermined thickness is integrally formed on the inner surface of the outer cylindrical fitting 6 by a similar vulcanization molding operation. Next, after housing the stopper member 26 in each recess 10 of the rubber sleeve 8, the bushing assembly is inserted into the outer cylindrical fitting 6 in a liquid tank containing an incompressible fluid as described above. . This fitting operation allows the fluid to be easily and effectively sealed into the fluid chamber 16 formed by the recess 10 of the rubber sleeve 8 and the inner circumferential surface of the outer cylindrical fitting 6. Then, the insert obtained in this way is held in the liquid tank as it is, or it is taken out from the liquid tank and placed in the atmosphere, and a squeezing operation is applied to the outer cylindrical fitting 6, and the ring 12 and By compressing the rubber layer 14 interposed between the outer cylindrical fitting 6 and the rubber layer 14, the seal between them is made perfect, and each fluid chamber 16 is reliably filled with incompressible fluid. Then, the opening edges on both sides of the outer cylindrical metal fitting 6 are sealed to prevent it from coming off, and the suspension bushing 2 as shown in FIGS. 1 and 2 is completed.

Such a suspension bushing 2 is suitably used, for example, in a four-link suspension mechanism. In that case, the outer cylinder fitting 6 is fitted into the arm eye (boss part) of the control arm, while a pivot provided on the vehicle body or axle housing is fitted inside the inner cylinder fitting 4. It will perform a vibration damping function.

Therefore, high frequency vibrations are mainly damped by the elastic deformation of the rubber sleeve 8, and low frequency vibrations are mainly damped by the two fluid chambers 1.
Based on the fluid flow effect generated when the incompressible fluid confined in the fluid chamber 6 flows from one fluid chamber 16 to the other fluid chamber 16 through an orifice consisting of a communication hole 22 and a liquid passage (18). It will be attenuated.

Then, a stopper member 2 is provided in each of the two fluid chambers 16.
6, even if a large vibration load is generated between the inner cylindrical metal fitting 4 and the outer cylindrical metal fitting 6, the rubber sleeve 8 will not undergo any larger deformation after a predetermined deformation. Bare, inner tube.

When a large displacement occurs between the outer cylinder side fittings 4 and 6 in a direction perpendicular to their axes, and the rubber sleeve 8 becomes greatly deformed, both the inner and outer stopper surfaces of the stopper member 26 touch the inner surface of the fluid chamber 16. This is because the stopper member 26 comes into contact with the rubber layer 24 of the ring body 20 to be formed and the rubber layer 14 of the outer cylinder fitting 6, and further deformation is prevented by the presence of the stopper member 26. In this way, excessive deformation of the rubber sleeve 8 is suppressed, so its durability is further improved, and when the rubber sleeve 8 is deformed, the tension between the part of the rubber sleeve 8 on the side receiving the tensile load and the outer cylinder metal fitting 6 is reduced. The seal is also maintained well, which also leads to improved sealing performance of the droplet 16.

Moreover, when a relative torsional load occurs between the inner cylinder fitting 4 and the outer cylinder fitting 6, the stopper member 26
Since it is not fixed to the side or the outer cylinder metal fitting 6 side,
Although some displacement occurs due to torsional deformation of the rubber sleeve 8, virtually no torsional load is applied to the stopper member 26 (therefore, during torsional deformation, both ends of the stopper member 26 in the curved direction are This prevents the side walls A and B of the chamber 16 from being repeatedly pressed, and as a result, the durability of the side walls A and B is greatly improved.In particular,
When the suspension bushing 2 is used under usage conditions where the torsional deformation applied to both metal fittings 4 and 6 is 10 degrees or more, if the stopper member 26 can properly receive the torsional load, the rubber sleeve 8
The deterioration in durability of parts A and B is significant,
In the bushing 2 of this embodiment, even under such usage conditions, the torsional durability of the portions A and B can be effectively enhanced.

In addition, in the bushing 2 having the above structure, since the opposing contact surfaces facing both sides of the stopper member 26 are formed by the rubber layers 14 and 24, contact between metals can be avoided, and contact between the metals can be avoided. Effective in suppressing sound. In addition, fluid chamber 1
The distance between the walls 26 gradually decreases toward the inside, and the stopper member 26 is always kept lifted from the communication hole 22 forming a part of the orifice.
Blockage of the flow of incompressible fluid is avoided.

Moreover, such an orifice is formed in the annular groove 18 of the inner cylinder fitting 4.
Since it is formed by the liquid passage formed by the inner peripheral surface of the ring body 20 and the communication hole 22 of the ring body 20, the effective cross-sectional area of the orifice is always constant regardless of the elastic deformation of the rubber sleeve 8. Therefore, stable damping performance against excitation vibration can be obtained.

Note that, as shown in FIG. 3, the rubber layer 24 of the ring body 20 forming the bottom wall surface of the fluid chamber 16 is formed in the width direction of the ring body 20 from the opening of the communication hole 22 on the side that opens to the fluid chamber 16. It is also possible to form grooves 28 extending to both side edges. In this way, even when the stopper member 26 is brought into contact with the surface of the rubber layer 24 of the ring body 20, the communication state between the fluid chamber 16 and the communication hole 22 is maintained through the groove 28, and both fluids A good flow of incompressible fluid between the chambers 16 is always ensured. In that case, the shape of the fluid chamber 16 and the length of the stopper member 26 may be determined so that the stopper member 26 can be seated on the rubber layer 24 of the ring body 20.

In the above embodiment, two metal rings 12 were provided on both sides of the outer peripheral surface of the rubber sleeve 8, but one metal cylindrical body was used instead of the two rings, and A window portion may be provided in a portion of the cylinder wall corresponding to the recess 10. Furthermore, such a ring 12 or cylinder may be useful in imparting precompression to the rubber sleeve 8.
It is also effective in making it easier to fit the outer cylinder fitting 6;
A bush structure without such a ring 12 or the like can also be adopted.

In addition, in the above example, the orifice that communicates the two fluid chambers 16 was formed by the annular groove 18 and the like across the inner cylinder fitting 4 and the ring body 20, but the orifice (
The communication passage) may be mainly formed of a groove partially formed on the outer circumferential surface of the inner cylinder fitting 4 as long as it has a structure that allows the fluid chambers 16 to communicate with each other. It is also possible to have a structure in which an orifice is provided on the metal fitting 6 side or in the rubber sleeve 8.

Furthermore, the number of fluid chambers 16 is not limited to two;
Alternatively, three or more fluid chambers may be provided, and if there are two or more fluid chambers, in addition to providing a stopper member in all of the fluid chambers, a stopper member may be provided in one of the fluid chambers. A configuration may also be adopted in which this is done.

In addition, various changes and modifications can be made to the present invention based on the knowledge of those skilled in the art without departing from the spirit thereof.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view (I-1 sectional view in FIG. 2) of a suspension bushing that is an embodiment of the present invention.
FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1. Further, FIG. 3 is an enlarged plan view showing the main parts of another embodiment of the present invention. 2: Suspension push (fluid-filled bush) 4:
Inner tube fitting (inner tube member) 6: Outer tube fitting (outer tube member) 8; Rubber sleeve (elastic body) 16: Fluid chamber 18: Annular groove (orifice) 2
0: Ring body 22: Communication hole 24; Rubber layer 26: Soba member 28: Groove

Claims (1)

[Claims] An outer cylinder member is arranged outside the inner cylinder member at a predetermined distance,
An elastic body is interposed between the inner cylindrical member and the outer cylindrical member to connect them, and a recess is provided in the elastic member, and an opening of the recess is closed with the outer cylindrical member. In the fluid-filled bushing, which forms a fluid chamber filled with a predetermined incompressible fluid, a metal sleeve is integrally attached to the outer peripheral surface of the elastic body so as not to cover the opening of the recess. At the same time, a sealing rubber layer of a predetermined thickness is integrally provided on the inner peripheral surface of the outer cylinder member, and the opening of the recess is closed by fitting the outer cylinder member onto the metal sleeve. On the other hand, an independent stopper member that is not fixed is accommodated in at least one of the fluid chambers, and the axes of the inner cylinder member and the outer cylinder member are adjusted by abutting the stopper member against the inner surface of the fluid chamber. A fluid-filled bush characterized by suppressing excessive relative displacement in a direction perpendicular to .