JPS647253B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved structure of a fluid-filled bushing, in particular, in addition to the vibration damping effect of an elastic member, the present invention effectively utilizes hydraulic damping force due to the inclusion of an incompressible fluid. This invention relates to a fluid-filled bushing that can be easily mass-produced.

Conventionally, in order to suspend differential gears, wheels, etc. to the body of an automobile, various types of suspension members such as arms, rods, and links have been attached so as to be swingable in various directions. Suspension bushings are generally incorporated into the pivot joints at both ends of the member for the purpose of dampening vibrations, and engine mounts are installed between them to suppress the transmission of vibrations from the engine to the vehicle body. It is mediated by

By the way, such bushes such as suspension bushes and engine mounts, in other words, anti-vibration supports, are generally made of an inner cylindrical metal fitting into which a predetermined pivot shaft is inserted for suspension of a vehicle, etc., and concentrically therewith. It has a structure in which an annular rubber sleeve is inserted between the outer cylindrical metal fitting and the vibration is damped by deforming the rubber sleeve, but recently, A composite bushing, in other words, a fluid-filled bushing, is proposed in which the rubber material forming the rubber sleeve does not have to have a particularly high damping coefficient, and is capable of generating a desirable damping function as a cushioning function of the bushing. It came to this.

In other words, Special Publication No. 1983-36151, Special Publication No. 1972
As disclosed in Publication No. 16554, etc., such a composite bushing has a plurality of recesses on the surface of a rubber sleeve inserted between an inner cylindrical metal fitting and an outer cylindrical metal fitting. Filling the pocket portion formed between the inner wall of the cylindrical metal fitting with a predetermined fluid,
These pockets have a structure in which they communicate through an orifice, and during excitation vibration, the fluid filled in one pocket flows through the orifice toward the other pocket, resulting in a good damping effect. is beginning to be demonstrated.

However, in such a conventional composite bush structure, the rubber sleeve is press-fitted into the outer cylindrical metal fitting to form the pocket portion, which causes problems such as deformation of the pocket portion and instability of the shape. There is a problem that requires post-adhesion between the outer cylinder metal fitting and the rubber sleeve after the press-fitting operation.
In addition, in order to fill the pocket with fluid and take out the air inside the pocket, after press-fitting a rubber sleeve into the outer cylindrical metal fitting,
As described in the above publication, all of these methods require troublesome work using a syringe needle, which significantly reduces the workability of bushing assembly, leading to higher costs. Furthermore, in such conventional composite bushing structures, there is considerable difficulty in applying pre-compression to the rubber sleeve in order to improve durability.

However, one possible solution to these problems is to adopt a structure in which a suitable rigid member is interposed between the outer cylinder fitting and the rubber sleeve. With the rigid member fixed to the outer circumferential surface of the rubber sleeve, it can be press-fitted into a predetermined outer cylindrical fitting in an incompressible fluid, thereby eliminating the need for the conventional post-adhesion process, and Advantages such as the fact that the pocket portion can be filled with fluid at the same time as the press-fitting operation are achieved, and assembly workability can be significantly improved. However, the structure in which a rigid member is interposed between the rubber sleeve and the outer cylindrical fitting has a problem with the sealing performance between the rigid member and the outer cylindrical fitting, and it remains to be seen what kind of sealing structure to adopt. This was a major challenge. In addition, since an O-ring or the like is generally used as a seal between two members, it is also possible to attach such an O-ring to the surface of a rigid member and seal between the outer cylinder metal fitting. It is extremely difficult to attach such an O-ring to a rigid member that is formed relatively thin in order to pre-compress the rubber sleeve. When the particles are present on the surface of the member, problems arise in which the pre-compression operation itself becomes difficult.

The present invention has been made against this background, and its main purpose is to improve a fluid-filled bushing that utilizes a fluid medium and has high damping characteristics. It is in.

Another object of the present invention is to provide a bushing structure that improves assembly or assembling workability, is excellent in mass productivity, and is capable of effectively performing preliminary compression while ensuring an effective sealing effect. It is about providing.

In order to achieve these objects, in the present invention, an annular elastic member is interposed between an inner cylindrical metal fitting and an outer cylindrical metal fitting that are arranged concentrically, and a plurality of ring-shaped elastic members are provided in the elastic member. separate recesses that communicate with each other via an orifice to define a plurality of pocket portions between the outer cylindrical fitting and the plurality of pocket portions, and a predetermined incompressible fluid is supplied to the plurality of pocket portions. an opening in each recess opening in the outer circumferential surface of the elastic member; A cylindrical outer rigid member is disposed on the outer circumferential surface so as not to cover the outer cylindrical part, while an elastic layer of a predetermined thickness made of an elastic material is provided on the inner surface of the outer cylindrical metal fitting, and through the elastic layer, The elastic member having the outer rigid member is fitted into the outer cylindrical fitting.

Thus, according to the present invention, an effective seal is achieved between the elastic member and the outer circumferential surface of the outer rigid member by the elastic layer formed on the inner surface of the outer cylinder fitting. Therefore, there is no need to provide any sealing means on the outer circumferential surface of the outer rigid member, and the elastic member can be effectively pre-compressed via the outer rigid member,
Furthermore, the preliminary compression operation can now be performed easily. Furthermore, when filling each pocket with a predetermined incompressible fluid, the elastic member having the outer rigid member is inserted into the outer cylindrical fitting having an elastic layer on the inner surface in the fluid. As a result, the operation becomes easy and reliable, and the assembly work of the bushing is significantly improved.In addition, by providing an elastic layer over the entire inner surface of the outer cylinder metal fitting, the operation becomes easy and reliable. This prevents the outer cylindrical metal fitting from coming into direct contact with the fluid contained in the pocket, thereby effectively preventing corrosion of the outer cylindrical fitting due to the fluid.

Further, in the present invention, while the predetermined outer rigid member is provided on the outer peripheral surface of the elastic member as described above, an elastic layer of a predetermined thickness made of an elastic material is provided on the inner surface of the outer cylinder fitting, and the elastic layer is The elastic member having the outer rigid member can be inserted into the outer cylindrical fitting through the elastic member, and the bottom of each recess forming the pocket portion is located between the elastic member and the inner cylindrical fitting. A cylindrical inner rigid member is provided in which a plurality of holes each opening in the cylinder wall are provided, and a groove is provided in the outer circumferential surface of the inner cylinder fitting where the holes of the inner rigid member are located, It is also characterized in that the respective recesses are made to communicate with each other by making these holes communicate with each other, and thereby, in addition to the above-mentioned excellent advantages, it also provides the following advantages. It has become possible to demonstrate its unique characteristics. In other words, since the respective recesses (pocket parts) are communicated with each other by grooves carved on the outer circumferential surface of the inner cylindrical metal fitting, which serve as communication passages that open at the bottom, leakage may occur during the manufacturing process. Even if air bubbles enter the recess due to liquid or the like, the air bubbles will collect at the top of the recess and have little risk of flowing into the opening of the groove at the bottom. Therefore, as before,
This also completely eliminates the disadvantage that air bubbles flow into the communication path on the outside of the bush, causing sudden changes in the orifice function and making the vibration damping function extremely unstable.

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

First, FIGS. 1 and 2 show an example of a single bushing constituting the suspension bushing according to the present invention, and FIG. 3 shows an example of an outer cylinder fitting, and furthermore, a fourth The figure shows the structure of a suspension bushing, which is an embodiment of the present invention, and is constructed by assembling the bushing alone and the outer cylinder metal fitting.

In FIG. 4, reference numeral 2 denotes a suspension bush according to an embodiment of the present invention, into which a pivot shaft supported by a pair of brackets fixed to the vehicle body, axle housing, etc. is inserted into the innermost part of the suspension bush. A relatively thick inner cylindrical metal fitting 4 is provided. Then, a relatively thin metal sleeve (inner rigid member) 6, a rubber sleeve (elastic member) 8, and two metal rings (outer rigid member) 10 are placed in contact with each other outward from the inner cylinder fitting 4, A single bushing 12 arranged concentrically and a rubber layer (elastic layer) 14 of a predetermined thickness fitted on the outside thereof.
The suspension bush 2 is constituted by the outer cylindrical metal fitting 16 having the following.

More specifically, as shown in FIGS. 1 and 2, the rubber sleeve 8 has an annular shape, and has two symmetrical grooves extending in the circumferential direction at corresponding positions on its outer peripheral surface. A ring 10 made of the two short relatively thin metal cylinders is provided on both ends of the outer peripheral surface of the rubber sleeve 8 in the axial direction so as to sandwich the opening of the recess 18. Each is provided. Further, the inner metal sleeve 6 has a hole 22 opened through the hole 22 at the bottom of the recess 18, and an inner cylindrical metal fitting 4 located below the hole 22. A ring-shaped circumferential groove 24 is provided on the outer peripheral surface of. Therefore, the circumferential groove 24 connects the two holes 22 to form an orifice, and the respective recesses 18 are brought into communication with each other.

Moreover, as shown in FIG. 4, such a recess 1
Separate pocket portions 26, 26 are respectively defined by the inner wall of the outer cylindrical fitting 16 which is fitted into the outer cylindrical fitting 16. ,
For example, an incompressible fluid 32 such as water, polyalkylene glycol, silicone oil, or a low molecular weight polymer is enclosed.

On the other hand, as shown in FIG.
A rubber layer 14 of a predetermined thickness made of rubber as an elastic material is integrally formed on the inner surface of almost the entire surface, and when the bushing unit 12 is inserted into the outer cylindrical fitting 16, Cylindrical metal fitting 1
6 and a ring 10 constituting the outer surface of the bushing unit 12 is liquid-tight to prevent a predetermined fluid 32 sealed in the pocket portion 26 from leaking.

In this way, the inner cylindrical metal fitting 4 and the outer cylindrical metal fitting 16
A predetermined precompression is applied to the rubber sleeve 8 placed between the The aim is to improve this.

It should be noted that the bush shown in FIGS.
The suspension bushing 2 as shown in FIG. 4, which is fitted into the suspension bushing 6, is a cylindrical member formed at the end of a suspension member in a vehicle suspension system, as shown in FIG. It is press-fitted into the arm eye 28 and attached.

By the way, the suspension bushing 2 as described above can be manufactured through the following steps.

First, when manufacturing a single bushing 12 as shown in FIGS. 1 and 2, a predetermined inner metal sleeve 6 made of metal and two short metal tubes kept at a predetermined distance in the axial direction are used. Ring 1 consisting of
0 are concentrically set in a predetermined mold, and a rubber material is injected into the gap between them and vulcanized to form the sleeve 6 and ring 10, and the rubber sleeve 8 is vulcanized and bonded. At the same time, it is vulcanized and molded. At this time, the rubber sleeve 8 has a plurality of recesses (here, two recesses 18, 18).
are simultaneously formed in positions that are open to the outer peripheral surface and are not covered by the two rings 10, and the bottoms of these recesses 18 are formed by the metal sleeve 6. It will be done. Note that a hole 22 is penetrated and opened in advance in the bottom forming portion of each recess 18 of the rubber sleeve 8 of the metal sleeve 6.

The inner cylindrical fitting 4 is then press-fitted into the vulcanized product 30 formed in this manner. An operation is employed in which the metal sleeve 6 is pressurized radially outward from its inner surface to enlarge (enlarge) its inner diameter. Note that an annular groove 24 is previously carved in the outer circumferential surface of the inner cylinder fitting 4 so as to be located below the hole 22 .
2 are made to communicate with each other. Then, in the single bush 12 formed by press-fitting the inner cylindrical metal fitting 4 in this manner, a squeezing operation is applied to the two rings 10 located on the outer peripheral surface thereof.
That is, by a known drawing method, for example, by an eight-way drawing method, or by press-fitting the bushing unit 12 into a die and applying a throttle to the ring 10 by the drawing part, the bushing unit 12 is drawn in the radial direction. Inward compressive deformation, ie, diameter reduction, is performed to obtain a predetermined outer diameter, and a predetermined pre-compression is then applied to the rubber sleeve 8 from the outside.

On the other hand, a rubber layer 14 having a predetermined thickness is separately formed integrally on the inner surface of the outer cylindrical metal fitting 16 by a similar vulcanization molding method.

Next, the bush 12 which has been subjected to the preliminary compression operation in this manner is inserted into the outer cylindrical fitting 16 having the rubber layer 14 in a liquid tank containing a predetermined incompressible fluid 32. Through this fitting operation, the fluid 32 is easily and effectively enclosed within the pocket portion 26 formed by the recess 18 in the bushing unit 12 and the inner peripheral surface of the outer cylindrical fitting 16. That's what happens. Then, the insert thus obtained is subjected to a diameter reduction by applying a restriction to the outer cylindrical fitting 16, either in the liquid tank as it is, or in the atmosphere after taking it out from the liquid tank. Thus, by imparting a compression effect to the rubber layer 14 interposed between the ring 10 and the outer cylindrical fitting 16, the sealing performance between them is improved.
In this way, each pocket 26 is completely filled with the incompressible fluid 32, and the desired suspension bushing 2 as shown in FIG. 4 is completed.

Therefore, the suspension bushing 2 having such a structure has the great advantage of being able to effectively pre-compress the rubber sleeve 8. That is, the desired pre-compression action can be applied to the bushing unit 12 formed by press-fitting the vulcanized product 30 into the inner cylindrical fitting 4 as described above via the ring 10 disposed on its outer circumferential surface. Therefore, a pre-compression operation is effectively applied to the rubber sleeve 8, and the adhesive surface between the rubber sleeve 8 and the metal sleeve 6, ring 10, etc. fixed by vulcanization adhesive is peeled off. This is effectively prevented, thereby significantly improving the durability of the rubber sleeve 8.

In particular, suspension bushing 2 with the above structure
According to this manufacturing method, the rubber sleeve 8 is subjected to preliminary compression from the ring 10, and the outer cylinder fitting 1
By reducing the diameter of 6 to a predetermined outer diameter, it receives preliminary compression from the outer cylinder metal fitting 16, and can also receive preliminary compression from the inner metal sleeve 6 if necessary. As a result, the durability of the rubber sleeve 8 is further improved. In addition, the rubber layer 14 interposed between the outer cylindrical fitting 16 and the ring 10 exerts an effective pressing action due to the preliminary compression from the outside, that is, the preliminary compression by reducing the diameter of the outer cylindrical fitting 16. As a result, the sealing effect between them is significantly enhanced, and the problem of leakage of the incompressible fluid 32 sealed within the pocket portion 26 is also more effectively resolved. It was reached.

In addition, regarding the sealing effect, the bushing alone has 12
is fitted into the outer cylindrical fitting 16 which has a rubber layer 14 on its inner surface, and by interposing the rubber layer 14 between the outer cylindrical fitting 16 and the ring 10, sealing is achieved. Therefore, the fluid filled in the pocket portion 26 will not leak from these gaps, and the sealing function can be achieved with a simple structure without using the conventional O-ring sealing mechanism. He was able to demonstrate his abilities. In addition, the outer cylindrical metal fitting 16 as described above
If the outer cylindrical fitting 16 is attached to the bushing unit 12 by a squeezing operation, problems such as damage or damage to the rubber seal 14 may occur, as would be the case if they were attached by a press-fitting operation. That's not the case at all. As a result, the operation of filling the pocket portion 26 with fluid can be performed extremely simply and easily, and the workability of assembling the bushing is significantly improved, and mass production thereof is also facilitated.

In addition, suspension bushing 2 with the structure of the above example
In this case, since the communication passages 22 and 24 that connect the two recesses 18 are provided on the inner cylindrical metal side, they are located deep in the fluid, so even if the bush is manufactured, gas may not be released. Even if gas enters or is generated during use of the bush, such gas will remain on the outer periphery of the recess 26, that is, on the inner cylindrical metal fitting side. Hole 22 and groove 24 corresponding to the diagonal of
There is almost no risk of air bubbles flowing into the tank. Therefore, in the conventional bushing structure, the problem of air bubbles flowing together with fluid into the communication path of the pocket portion 26, causing a sudden change in the orifice function and making its damping characteristics extremely unstable, can be effectively solved. It became possible to do so. Note that even if air bubbles enter the lower pocket portion 26, such air bubbles will pass through the groove 24 and enter the upper pocket portion 26.
Therefore, air bubbles that enter the lower pocket part rarely pose a problem.

Furthermore, in the structure of the above example, the two pocket portions 26
The communication path that connects the groove 24 and the metal sleeve 6
Since it is formed by the inner circumferential surface of
Since its shape is always kept constant, in other words, the cross-sectional area of the fluid passage is kept unchanged, the flow action corresponding to the external force applied to the bush 2 is also constant, and therefore the excitation vibration The damping performance against the damping force was also stabilized, and the desired damping function could be permanently obtained.

In the above embodiment, the outer rigid member is constructed using two rings 10, thereby eliminating the need to provide an opening in the outer rigid member at a portion corresponding to the recess 18 of the rubber sleeve 8. An unnecessary effect was produced, which was extremely advantageous from the viewpoint of manufacturing the bushing.Of course, instead of the two rings 10, a single metal cylinder was used, and the recess 18 in the cylinder wall was filled with the metal cylinder. There is no problem even if a window is provided in the corresponding part.

Further, in the above example, a predetermined rubber layer 14 was provided over the entire inner surface of the outer cylinder fitting 16 to facilitate the formation operation of the rubber layer 14 on the outer cylinder fitting 16. As shown in FIG. 6, it is also possible to provide the rubber layer 34 over a predetermined length of both ends of the outer cylinder fitting 16 in the axial direction. Of course, the rubber layer 34 that is divided and provided in the outer cylinder fitting 16 in this way is different from that of the ring 10 in the previous example.
It will be installed at a position corresponding to

Furthermore, even if there is a communication path that connects the two pocket parts 26, there is no problem in providing it on the outer cylindrical metal fitting 16 side instead of providing it on the inner cylindrical metal fitting 4 side as in the above example. There is no problem even if such a communication path is provided in the outer rigid member 10 itself.

Furthermore, in the above example, a circumferential groove 24 is provided along the circumferential surface of the inner cylinder fitting 4, and a communication path is formed between the circumferential groove 24 and the inner metal sleeve 6. However, such a communication path may be a groove partially provided on the outer peripheral surface of the inner cylindrical fitting 4, as long as the pocket portions 26 are structured to communicate with each other, or may be a groove formed partially on the outer circumferential surface of the inner cylinder fitting 4. Instead of arranging the sleeve 6 on the entire inner surface of the rubber sleeve 8, as shown in FIG.
It is also possible to use a ring 36 that is partially disposed only around 4. In addition, such a ring 36
When using the rubber sleeve 8, the vulcanization molding operation of the rubber sleeve 8 is carried out in the presence of the inner cylindrical fitting 4 which is press-fitted into the ring 36 and has a communication path formed therein.

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 showing a single bushing used in a suspension bushing, which is one of the fluid-filled bushes according to the present invention, and FIG.
FIG. 3 is a cross-sectional view of an outer cylindrical metal fitting into which such a single bushing is inserted. 4 is a sectional view corresponding to FIG. 2 of a suspension bush obtained by fitting and inserting the outer cylindrical fitting of FIG. 3 into the bush of FIG. 1, and FIG. FIG. 4 is a sectional view corresponding to FIG. 3 showing a state in which the bushing is further press-fitted into the arm eye of the suspension member. FIG. 6 is a view corresponding to FIG. 3 showing another embodiment of the outer cylinder metal fitting in which a rubber layer is formed on the inner surface. FIG. 7 is a cross-sectional view showing another embodiment of the present invention. 2: Suspension bushing, 4: Inner cylinder metal fittings,
6: Metal sleeve, 8: Rubber sleeve, 10: Ring, 12: Button unit, 14, 34: Rubber layer, 16: Outer cylinder metal fitting, 18: Recess, 22: Hole,
24: Circumferential groove, 26: Pocket portion, 32: Incompressible fluid.

Claims (1)

[Scope of Claims] 1. An annular elastic member is interposed between an inner cylindrical metal fitting and an outer cylindrical metal fitting that are arranged concentrically, and a plurality of elastic members are made to communicate with each other via orifices. By providing separate recesses to define a plurality of pocket portions between the outer cylindrical metal fitting and filling a predetermined incompressible fluid in the plurality of pocket portions, the incompressible fluid can be In the bush which allows the fluid to flow from one pocket part to the other pocket part through the orifice, a groove is formed on the outer peripheral surface of the elastic member so as not to cover the opening of each recess opening in the outer peripheral surface of the elastic member. While a cylindrical outer rigid member is disposed, an elastic layer of a predetermined thickness made of an elastic material is provided on the inner surface of the outer cylindrical fitting, and the elastic member having the outer rigid member is connected to the outer side through the elastic layer. A fluid-filled bushing structure characterized by being able to be fitted into a cylindrical metal fitting. 2. The bushing structure according to claim 1, wherein the elastic member is pre-compressed via the outer rigid member. 3. An annular elastic member is interposed between an inner cylindrical metal fitting and an outer cylindrical metal fitting that are arranged concentrically, and a plurality of separate recesses that are communicated with each other are provided in the elastic member. A bush that defines a plurality of pocket portions between the elastic member and the inner cylindrical metal fitting, and a predetermined incompressible fluid is sealed in the plurality of pocket portions; A cylindrical inner rigid member is provided in which the cylindrical wall is penetrated by a plurality of holes that open at the bottoms of the respective recesses, while By providing grooves on the outer peripheral surface and communicating the holes, the recesses are made to communicate with each other, and the openings of the recesses opening on the outer peripheral surface of the elastic member are not covered. To,
A cylindrical outer rigid member is disposed on the outer peripheral surface, and an elastic layer of a predetermined thickness made of an elastic member is provided on the inner surface of the outer cylindrical metal fitting, and the outer rigid member is provided through the elastic layer. A fluid-filled bushing structure characterized in that an elastic member is fitted into the outer cylindrical metal fitting. 4. The outer rigid member is composed of two short metal cylinders, and is arranged on the outer circumferential surface of the elastic member at both ends in the axial direction so as to sandwich the opening of the recess that opens on the outer circumferential surface of the elastic member. A bushing structure according to claim 3. 5. The outer rigid member and the inner rigid member are
4. The bushing structure according to claim 3, wherein the bushing structure is vulcanized and bonded to the outer circumferential surface and inner circumferential surface of the elastic member, respectively, when the elastic member is vulcanized and molded. 6. The bushing structure according to claim 3, wherein the elastic layer is formed over substantially the entire inner surface of the outer cylindrical fitting. 7. The bushing structure according to any one of claims 3 to 6, wherein the elastic member is pre-compressed via the outer rigid member. 8. The bushing structure according to any one of claims 3 to 7, wherein the outer cylindrical metal fitting is reduced in diameter after the elastic member having the outer rigid member is inserted and inserted.