JPH0223882Y2 - - Google Patents

Description

[Detailed description of the invention] (Technical field) The present invention relates to a fluid-filled anti-vibration bushing that utilizes the elasticity of rubber and the resonance effect and flow resistance of fluid.
In particular, the present invention relates to improvements in the orifice structure for causing the fluid to flow.

(Prior art) Conventionally, fluid-filled vibration isolating bushings have been developed that combine the elasticity of rubber with the resonance action and flow resistance of a fluid to produce a large damping effect against low-frequency vibrations due to the resonance action and flow resistance of the fluid. For example, it is used in suspension bushes and engine mounts for vehicles. This is usually done by arranging an inner cylindrical metal fitting and an outer cylindrical metal fitting concentrically with each other at intervals in the radial direction, and providing a cylindrical rubber-like elastic body between the inner cylindrical metal fitting and the outer cylindrical metal fitting. A pair of fluid chambers are formed in the rubber elastic body so as to be located on both sides in the radial direction with the inner cylindrical fitting in between, and each of the fluid chambers is filled with a predetermined incompressible fluid. The chambers are communicated with each other by an orifice (communication means) to allow fluid to flow between the fluid chambers.

In the case of such a fluid-filled anti-vibration bushing, as shown in Japanese Patent Laid-Open No. 56-164242, etc., a metal sleeve is usually fixed integrally on the outer peripheral surface of the rubber elastic body. The orifice is formed between the fluid chamber and the outer cylindrical fitting so as to extend across the fluid chamber in the circumferential direction. That is, in the vibration-proof bushing having such a structure, the passage length of the orifice corresponds to a little less than half the circumference of the outer cylindrical metal fitting.

Furthermore, as one of such fluid-filled anti-vibration bushings, the applicant of the present application previously published Japanese Patent Application Laid-Open No. 59-164428.
As disclosed in the publication, a block body is integrally fitted into the outer periphery of the inner cylindrical metal fitting, and this block body is fixed so as to protrude into a pair of fluid chambers, so that the block body can be positioned in each fluid chamber. The proposed block body functions as a stopper that comes into contact with the inner circumferential surface of the outer cylindrical metal fitting when a large load is applied, thereby preventing excessive displacement between the inner cylindrical metal fitting and the outer cylindrical metal fitting.

By the way, in such a type of anti-vibration bushing in which the block body is fitted into the inner cylindrical metal fitting, the communication means for communicating the pair of fluid chambers with each other is formed at the boundary of the fitting part between the block body and the inner cylindrical metal fitting. The annular passage includes a circular passage, and a communication portion that communicates the annular passage with a pair of fluid chambers.
For example, by covering an annular groove formed on the inner circumferential surface of the block body with the outer circumferential surface of the inner cylindrical metal fitting, or by covering an annular groove formed on the outer circumferential surface of the inner cylindrical metal fitting with the inner circumferential surface of the block body. In particular, an annular passage is formed which acts as an orifice. As a result, the fluid that reaches the annular passage from one fluid chamber via the communication part is divided into two parts, reaches the communication part on the opposite side, and from there flows into the other fluid chamber, so the passage actually functions as an orifice. The length corresponds to a little less than half the circumference of the inner cylindrical metal fitting.

(Problem to be solved by the invention) Therefore, the phase angle peak frequency of the fluid-filled bushing as described above: c, in other words, the frequency at which the resonance effect of the fluid or the vibration damping effect due to flow resistance is greatest is , is determined by orifice cross-sectional area/orifice length. Therefore, the phase angle peak frequency: c has a small orifice cross section,
The longer the orifice length, the smaller the value, but if the orifice cross section is small, the amount of fluid movement will be small and it will be difficult to produce a damping effect, so the phase angle peak frequency should be adjusted to the low frequency range where damping is most needed. And in order to obtain a high attenuation effect in the low frequency range,
It is effective to ensure the length of the orifice as long as possible while maintaining a sufficient amount of fluid movement without reducing the cross-sectional area of the orifice.

However, in the fluid-filled bushings of conventional structure as disclosed in the above-mentioned Japanese Patent Application Laid-open No. 56-164242 and Japanese Patent Application Laid-open No. 59-164428, approximately half the circumference of the outer cylindrical metal fitting or the inner cylindrical metal fitting is The orifice cannot be made longer than the orifice length corresponding to A problem arises in that the amount of movement of the fluid decreases, and the damping effect on low frequency vibrations decreases accordingly.

(Means for Solving the Problems) The present invention was made in order to solve the problem of the orifice, that is, the communication means, in a fluid-filled bushing equipped with an inner cylinder metal fitting, an outer cylinder metal fitting, and a block body as described above. and the means of communication,
It is formed in a spiral shape at the fitting part between the block body and the inner cylindrical metal fitting. More specifically, a spiral passage is formed at the fitting part between the block body and the inner cylindrical fitting, from one fluid chamber side to go around the inner cylindrical fitting at least one and a half times to the other fluid chamber side. Both ends of the passage were made to communicate with the pair of fluid chambers through the communication portions. Note that such a spiral passage may be formed by covering a spiral groove formed on the inner circumferential surface of the block body with the outer circumferential surface of the inner cylindrical metal fitting, or by covering a helical groove formed on the outer circumferential surface of the inner cylindrical metal fitting with the outer circumferential surface of the block body. It is also possible to cover the inner peripheral surface.

(Effect of the invention) As described above, if the communication means (orifice) is mainly composed of the spiral passage formed at the fitting part of the block body and the inner cylinder fitting, the length of the orifice is at most half the circumference of the inner cylinder fitting. The length can be at least three times longer than that of the conventional annular orifice. Therefore, the orifice cross section can be kept large to maintain sufficient fluid displacement, and the long orifice allows the phase angle peak frequency to be matched to the low frequency range where attenuation is most needed. This made it possible to produce a high attenuation effect in that low frequency range.

In addition, forming a spiral orifice extending in the circumferential direction at the fitting part between the block body and the inner cylinder fitting in this way makes extremely efficient use of the limited space due to the unique structure of the bush. This is because the size of the bushings does not become a problem.

(Embodiments) Hereinafter, first and second embodiments of the present invention will be described in detail based on the drawings.

First, in FIGS. 1 and 2, reference numeral 2 denotes a thick-walled cylindrical inner cylindrical metal fitting, and on the outside of this inner cylindrical metal fitting 2, there is a thin-walled cylindrical outer cylinder at a predetermined interval in the radial direction. The metal fittings 4 are arranged concentrically. A cylindrical rubber sleeve 6 functioning as a rubber elastic body is integrally provided between the inner cylindrical metal fitting 2 and the outer cylindrical metal fitting 4. This rubber sleeve 6 is vulcanized and bonded on the inner circumferential surface to the outer circumferential surface of the inner cylindrical metal fitting 2, and is vulcanized and bonded on the outer circumferential surface to the inner circumferential surface of the outer sleeve 8. It is held within the metal fitting 4. A thin sealing rubber layer 10 is fixed to the inner peripheral surface of the outer cylindrical metal fitting 4, and this rubber layer 10 seals between the outer cylindrical metal fitting 4 and the outer sleeve 8.

Further, a pair of fluid chambers 12 and 14 are formed in the rubber sleeve 6 so as to be located symmetrically on both sides in the radial direction with the inner cylinder fitting 2 interposed therebetween. These fluid chambers 12 and 14 are formed by closing the openings of two recesses opening in the outer circumferential surface of the rubber sleeve 6 with the outer circumferential surface of the inner tube fitting 2 as bottoms, respectively, with the outer tube fitting 4. The outer sleeve 8 is provided with windows 16 corresponding to the openings of these recesses. And these fluid chambers 1
In 2 and 14, any one of incompressible fluids such as alxylene glycol, polyalkylene glycol, silicone oil, low molecular weight polymer, or water, alone or in an appropriate combination, is enclosed. There is.

On the other hand, on the outside of the inner cylindrical metal fitting 2, a substantially rectangular block body 18 is integrally fitted into a fitting hole 20 formed at the center thereof. This block body 18 extends symmetrically from the inner cylindrical fitting 2 in its radial direction and is thrust into the fluid chambers 12 and 14, respectively.
The protruding end portion of the outer cylindrical metal fitting 4 can come into contact with the inner circumferential surface of the outer cylindrical metal fitting 4 via the seal rubber layer 10, so as to function as a stopper to prevent excessive displacement between the inner cylindrical metal fitting 2 and the outer cylindrical metal fitting 4. It's getting old.

The inner peripheral surface of this block body 18, that is, the fitting hole 2
As shown in FIGS. 3 to 5, a spiral groove 22 is formed on the inner peripheral surface of the block body 18 along a helical winding centered on the center line of the block body 18. This spiral groove 22 starts from the fluid chamber 12 side, goes around the inner cylinder fitting 2 one and a half times, and then goes around the fluid chamber 14 on the opposite side.
It is made to reach the side. One end of the spiral groove 22 communicates with a communication hole 24 and the other end communicates with a communication hole 26, and these communication holes 24 and 26 are connected to the center line by the lead of the spiral groove 22. They are formed at different positions in the direction and play the role of communication portions, and both penetrate through each thick portion of the block body 18 and open at both ends in the longitudinal direction.

Such a block body 18 is firmly fitted into the outer circumferential surface of the inner cylinder metal fitting 2, so that the spiral groove 22 is covered with the outer circumferential surface of the inner cylinder metal fitting 2, and thereby the block body 18 and the inner cylinder fit together. A spiral passage 28 having a length corresponding to one and a half circumferences of the inner cylinder fitting 2 is formed at the boundary of the fitting portion with the metal fitting 2. One end of the spiral passage 28 is communicated with the fluid chamber 12 through the communication hole 24, and the other end thereof is communicated with the fluid chamber 14 through the communication hole 26. and 26, both fluid chambers 12
A communication means for communicating between the fluid chambers 12 and 14 is configured, and by causing the fluid to flow between both fluid chambers 12 and 14 through this communication means, the resonance effect or flow of the fluid flowing in the spiral passage 28 is achieved. The resistance can provide a vibration damping effect. Note that the communication holes 24 and 26
Depending on the size of the communicating holes 24,
26 can also be seen as an orifice.

By the way, in order to obtain such a fluid-filled bushing, for example, a rubber sleeve 6 is inserted between the outer sleeve 8 and the block body 18 integrally fitted into the inner cylinder fitting 2 by press fitting, shrink fitting, etc. The rubber sleeve 6 is vulcanized and simultaneously vulcanized and bonded to form an integral bushing assembly, and if necessary, the rubber sleeve 6 is pre-compressed by drawing the outer sleeve 8. On the other hand, on the inner peripheral surface of the outer cylinder fitting 4,
The seal rubber layer 10 is integrally vulcanized and molded in advance. Then, in the fluid as described above, fit this bushing assembly into the outer cylindrical metal fitting 4,
In addition, a pair of fluid chambers 12 and 14 are formed by squeezing the outer cylindrical metal fitting 4 in all directions, and at the same time, a fluid is sealed in them, and then both side edges of the outer cylindrical metal fitting 4 are roll caulked to form the outer sleeve 8. Once fixed, it becomes a fluid-filled bushing with a spiral passage 28 as described above.

Such a fluid-filled bushing is generally interposed between two objects to be vibration-isolated, and
The inner cylindrical metal fitting 2 is attached to either one of the objects to be vibration-isolated, and the outer cylindrical metal fitting 4 is attached to the other object for use, and can be suitably used, for example, as a vibration-proof bushing for a tension rod in a vehicle suspension. .

Based on the relative displacement between the inner cylindrical metal fitting 2 and the outer cylindrical metal fitting 4, fluid is caused to flow between the fluid chambers 12 and 14 through the spiral passage 28 and the like. At that time, the passage that functions as an orifice is spiral passage 2.
8 to a length equivalent to one and a half circumferences of the inner cylindrical fitting 2, while maintaining its passage cross-sectional area large enough to ensure a sufficient flow of fluid.
The lengthened orifice 28 makes it possible to match the phase angle peak frequency to the optimum frequency in the low frequency range, and as a result, it is possible to obtain a large damping effect in the low frequency range where attenuation is most needed. .

Next, another embodiment of the present invention will be described based on FIGS. 6 to 10.

In this embodiment, as is clear from FIGS. 6 and 7, no spiral groove is formed on the inner circumferential surface of the block body 18, but instead, as shown in FIGS.
As is clear from the figure, a spiral groove 30 is formed on the outer circumferential surface of the inner cylinder fitting 2. This spiral groove 30 goes around the inner cylinder fitting 2 approximately one and a half times,
Not all of them are spiral-shaped. That is,
Circumferential grooves 32 extending approximately half a circumference along the circumference of the inner cylindrical fitting 2 at a predetermined distance in the axial direction of the inner cylindrical fitting 2.
and 34 are formed, and the diagonal ends of these circumferential grooves 32 and 34 with respect to the center of the inner cylinder fitting 2 are connected by a helical groove 36 to form one continuous spiral. This is called the groove 30.

Further, from the other end of the circumferential groove 34, an axial groove 38 is formed which extends in a key shape toward the other circumferential groove 32 in the axial direction of the inner cylinder fitting 2.
A similar short axial groove 40 is formed at the other end of the inner cylindrical fitting 2.
are located symmetrically about the center line of

Then, on the outside of such an inner cylindrical fitting 2, a sixth
Block body 18 as shown in FIG.
By being firmly fitted, the spiral groove 30 formed in the inner cylindrical fitting 2 is covered with the inner circumferential surface of the block body 18, and a spiral passage is formed at the boundary between them. In addition, communication holes 42 and 44 are formed in the block body 18 symmetrically through both thick-walled portions in the longitudinal direction.
8 is fitted into the inner cylinder fitting 2, the communication hole 4
2 is communicated with the axial groove 38, and the communication hole 44 is communicated with the axial groove 40, so that both ends of the spiral passage 30 in this example are connected to both fluid chambers 12 and 14 as in the previous embodiment. The orifice is constructed mainly from these spiral passages. The other parts are the same as those in the previous embodiment, so the explanation will be omitted.

As is clear from the above explanation, the spiral passage, which is the main body of the orifice, does not have to be a spiral that strictly follows the helical winding, but rather can go around the inner cylindrical fitting 2 without intersecting. It's good to have it.

In addition, in the explanation so far, both ends of the spiral passage are connected to the communication holes 24 and 26 formed in the block body 18.
Alternatively, the axial length of the helical groove is made longer than the thickness of the block body 18, and both ends of the helical groove are connected to both end faces of the block body 18. Each of the fluid chambers may be opened. In this case, the openings on both sides of the helical groove function as communication portions.

Furthermore, it goes without saying that the length of the spiral passage is not limited to one that goes around the inner cylindrical metal fitting one and a half times, but may have a length that goes around two and a half times, three and a half times, or even more.

Furthermore, the present invention can be applied not only to suspension bushings such as the tension rod bushings described above, but also to other vibration-proof bushings such as engine mounts.

In addition, although not explained in detail, it is possible to implement the present invention with various changes, improvements, etc. based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a vibration-proof bushing that is an embodiment of the present invention, and corresponds to the - section in FIG. 2, and FIG. 2 is a side view of the bushing shown in FIG. 1. It is. 3 is a front view of the block body in FIG. 1, FIG. 4 is a sectional view taken along the line V--V in FIG. 3, and FIG. 5 is a sectional view taken along line V-V in FIG. FIG. 6 is a front view of a block body according to another embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along the line shown in FIG. FIG. 8 is a side view of an inner cylinder fitting used with the block body shown in FIGS. 6 and 7 in another embodiment of the present invention;
9 is a cross-sectional view taken from FIG. 8, and FIG. 10 is a side view of the inner cylindrical fitting shown in FIG. 8, viewed from another angle. 2...Inner cylinder metal fitting, 4...Outer cylinder metal fitting, 6...Rubber sleeve (rubber elastic body), 12, 14...Fluid chamber,
18...Block body, 22,30...Spiral groove, 2
4, 26, 42, 44...Communication hole (communication part), 3
2, 34... Circumferential groove, 36... Spiral groove, 3
8, 40...Axial groove.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) An inner cylindrical metal fitting, an outer cylindrical metal fitting arranged concentrically at a predetermined interval in the radial direction on the outside of the inner cylindrical metal fitting, and the inner cylindrical metal fitting and the outer cylinder. A cylindrical rubber elastic body provided between the metal fitting, and a predetermined incompressible fluid sealed in the rubber elastic body, which is formed so as to be located on both sides of the inner cylinder metal fitting in the radial direction. a pair of fluid chambers that are connected to each other; a block body that is integrally fitted into the outer periphery of the inner cylindrical fitting and positioned so as to face each of the pair of fluid chambers; and a block body that allows the pair of fluid chambers to communicate with each other. , a fluid-filled anti-vibration bushing including communication means for causing the fluid to flow between the fluid chambers, the communication means being connected to the fitting portion of the block body and the inner cylinder fitting at least one and a half times around the inner cylinder fitting. A fluid-filled anti-vibration bushing characterized in that it is comprised of a spiral passage formed so as to circulate as described above, and communication portions that connect both ends of the spiral passage to the pair of fluid chambers, respectively. (2) The utility model according to claim 1, wherein the spiral passage is formed by covering a spiral groove formed on the inner circumferential surface of the block body with the outer circumferential surface of the inner cylindrical metal fitting. Anti-vibration bushing. (3) The utility model according to claim 1, wherein the spiral passage is formed by covering a spiral groove formed on the outer circumferential surface of the inner cylindrical metal fitting with the inner circumferential surface of the block body. Anti-vibration bushing.