JPH0349315Y2 - - Google Patents

Description

[Detailed description of the invention] (Technical field) The present invention relates to a cylindrical fluid-filled vibration-isolating bushing that mainly dampens vibrations input in the radial direction of the bushing. The present invention relates to a fluid-filled vibration isolating bushing that can advantageously obtain a vibration damping effect as well as a vibration isolation effect when vibration is input in a medium to high frequency range.

(Background Art) Conventionally, as a type of anti-vibration bushing that is interposed between members constituting a vibration transmission system and connects them in a vibration-proof manner, it has been used, for example, in automobile suspension bushes and FF (front engine/front drive). ) There are known cylindrical engine mounts that have a generally cylindrical shape as a whole and are designed to attenuate or block vibrations input mainly in a predetermined direction in the radial direction.

As for such anti-vibration bushings, the applicant of the present application previously proposed Utility Model Application No. 61-100614 and
No. 61-100615, it is constructed by connecting an inner cylindrical metal fitting and an outer cylindrical metal fitting that are arranged concentrically or eccentrically to each other with a cylindrical rubber elastic body interposed between them. The connecting body is provided with a plurality of fluid chambers separated in the circumferential direction, each of which is sealed with a predetermined incompressible fluid and communicated with each other through an orifice passage. At least one of the fluid chambers into which vibrations to be damped are input is provided with a constriction that is integrally attached to the inner cylindrical metal fitting or the outer cylindrical metal fitting and between the inner wall surface of the fluid chamber and the inner cylindrical metal fitting. A so-called fluid-filled anti-vibration bushing has been revealed, which has a structure in which an umbrella member forming a section is arranged.

In other words, in the case of a vibration-proof bushing having such a structure, when vibration is input in a low frequency range, the cylindrical rubber elastic body is elastically deformed by the vibration load input between the inner and outer cylindrical metal fittings, and the cylindrical rubber elastic body is formed inside. By changing the volume (internal pressure) of the fluid chambers, the fluid flow through the orifice passages, that is, liquid column resonance, which is caused between the fluid chambers based on the internal pressure changes, increases the resistance to input vibration. On the other hand, when a vibration input in the medium to high frequency range causes the orifice passage to become substantially blocked, the enclosed fluid is reduced due to the constriction formed in the fluid chamber. The liquid column resonance can reduce the spring constant of the entire bushing, that is, reduce the vibration transmissibility.

However, even in a vibration-proof bushing having such a structure, the frequency range in which the vibration transmissibility reduction effect due to the liquid column resonance of the sealed fluid in the narrowed part can be exhibited is narrow, so the orifice passage becomes blocked, It has been extremely difficult to reduce the vibration transmissibility in multiple or wide areas of high frequencies.

And for that purpose, e.g.
When applied to the engine mount of a FF vehicle, the frequency range in which the vibration damping effect of the orifice passage can be advantageously demonstrated is set to approximately 10 Hz, and while damping low frequency large amplitude vibrations such as engine shake, When trying to prevent muffled sounds such as engine transmitted sound by setting the frequency range of the liquid column resonance of the enclosed fluid in the constricted part to 200 to 300 Hz, the frequency range of 50 to 150 Hz is set.
When inputting vibrations in the medium frequency range of around Hz, the vibration transmission rate becomes extremely large, causing problems such as medium-speed muffled sounds and beat sounds.
In such a wide frequency range of medium to high frequencies, there is still room for improvement in engine mounts and the like that require a low dynamic spring constant against input vibration.

(Solution Means) Here, the present invention was made against the background of the above-mentioned circumstances, and its feature is that the inner cylinder metal fitting and the outer cylinder metal fitting are arranged concentrically or eccentrically with respect to each other. are connected by a cylindrical rubber elastic body interposed between them to form a connecting body, and a predetermined incompressible fluid is sealed inside the connecting body, and they are mutually connected through an orifice passage. A plurality of fluid chambers are provided separated in the circumferential direction and communicated with each other, and the inner cylindrical metal fitting or In a fluid-filled vibration isolating bushing including an umbrella member that is integrally attached to the outer cylindrical metal fitting and forms a constricted portion between it and the inner wall surface of the fluid chamber, the vibration to be damped is inputted. A movable member or an elastic member is disposed on the peripheral wall of the fluid chamber so as to constitute the inner wall surface of the fluid chamber, and the movable member or the elastic member is disposed in a predetermined amount of displacement or deformation in the radial direction of the bush. Therefore, a hydraulic pressure absorption mechanism is provided that can absorb the increase in hydraulic pressure when vibration is input into the fluid chamber.

(Effect of the invention) In other words, in the fluid-filled vibration isolating bushing having the structure according to the invention, the constriction can reduce the vibration transmissibility when vibration is input in a predetermined frequency range due to liquid column resonance. In addition to this, a hydraulic pressure absorption mechanism is provided that can absorb the increase in hydraulic pressure in the fluid chamber when vibration is input in a predetermined frequency range and reduce the vibration transmissibility by displacing or deforming a movable member or an elastic member. By setting different frequencies for the narrowed portion and the hydraulic pressure absorption mechanism, the vibration transmission rate can be further reduced in the medium to high frequency range where the orifice passage is closed. This can be effectively achieved over a wide frequency range.

(Examples) Hereinafter, in order to clarify the present invention more specifically, examples of the present invention will be described in detail with reference to the drawings. Here, an example will be described in which the present invention is applied to a cylindrical engine mount for a front-wheel drive vehicle.

First, FIGS. 1 to 3 show a cylindrical engine mount for a front-wheel drive vehicle having a structure according to the present invention. In these figures, 10 and 12
are an inner cylindrical metal fitting and an outer cylindrical metal fitting, respectively, and are arranged eccentrically by a predetermined distance in the radial direction of the mount. Moreover, a rubber elastic body 14 is interposed between the inner cylinder metal fitting 10 and the outer cylinder metal fitting 12, and the inner cylinder metal fitting 10 and the outer cylinder metal fitting 12 are integrated with each other by the rubber elastic body 14. are connected both physically and elastically.

The engine mount is attached to the mounting shaft of the vehicle body side or the power unit including the engine in the inner cylinder fitting 10 by being fitted onto the mounting shaft, while the engine mount is attached to the cylindrical holding part of the vehicle body side or the power unit side in the outer cylinder fitting 12. inserted and installed,
This allows the power unit to be supported against vibrations against the vehicle body. In addition, in the case of the mount in this embodiment, when the mount is mounted on an actual vehicle, the engine load is applied between the inner and outer cylindrical metal fittings 10 and 12, so that the two metal fittings 10 and 12 are positioned approximately concentrically. .

More specifically, the rubber elastic body 14 has a cylindrical shape with a space 20 having a substantially arcuate cross section penetrating in the mount axis direction on the side where the distance between the inner and outer cylindrical fittings 10 and 12 in the eccentric direction is smaller. As shown in FIGS. 4 to 6, the inner circumferential surface thereof is integrally vulcanized and bonded to the outer circumferential surface of the inner cylindrical metal fitting 10, and the outer circumferential surface includes a substantially cylindrical sealing sleeve 16.
are vulcanized and bonded together. This seal sleeve 16 has approximately rectangular window portions 1 at positions facing each other in the eccentric direction of the inner and outer cylindrical fittings 10 and 12.
8 and 18 are provided, and between the window portions 18 and 18, a groove portion 22, which opens toward the outer circumferential side, is provided so that the circumferential ends of the respective window portions 18 and 18 communicate with each other. 22 is formed.

Furthermore, the rubber elastic body 14 is provided with an opening on the outer circumferential surface through the window 18 at a portion of the seal sleeve 16 that corresponds to the window 18 in the direction in which the distance between the inner and outer cylindrical fittings 10 and 12 increases. A pocket portion 24 having a predetermined depth is formed. On the other hand, in a portion of the seal sleeve 16 corresponding to the other window portion 18, a thin film-like elastic bag portion 26 is provided to close the window portion 18 from the inside.
The bag portion 26 protrudes into the cavity 20 and is integrally molded with the rubber elastic body 14, and a recess 28 having a variable volume with the window portion 18 as an opening is formed in the bag portion 26.

As shown in FIGS. 1 and 2, a seal is placed on the outer peripheral surface of the integrally vulcanized product of the rubber elastic body 14 having such a pocket portion 24 and a recess 28. Groove 2 of sleeve 16
2, a pair of semi-cylindrical orifice division bodies 30, 31 are integrally assembled on the outer circumferential surface so as to have a cylindrical shape as a whole. body 30, 31
By closing the openings of the pocket portion 24 and the recess 28, two fluid chambers, namely a pressure receiving chamber 36 and an equilibrium chamber 38, are formed.

In addition, these orifice division bodies 30, 31
is provided with an orifice groove 34 on its outer circumferential surface that extends in the circumferential direction for a length of approximately half a circumference in the assembled state, and the orifice groove 34
are communicated with the pressure receiving chamber 36 and the equilibrium chamber 38, respectively, at both end portions in the length direction thereof, through communication holes 40 provided at the bottom.

Furthermore, in this way, the orifice divided bodies 30, 3
The integrally vulcanized molded product to which 1 is assembled includes an outer cylindrical metal fitting 12 integrally equipped with a seal rubber 42 on the inner peripheral surface.
The opening of the orifice groove 34 in the orifice divided bodies 30, 31 is covered by the outer fitting and the diameter reduction process, whereby the orifice divided bodies 30, 31 and the outer cylinder metal fitting are covered. 12, the pressure receiving chamber 36 and the equilibrium chamber 3
8 are formed with an orifice passage 44 that allows them to communicate with each other with a predetermined flow cross-sectional area.

In addition, the outer cylindrical fitting 12 is fitted into the integrally vulcanized molded product into the pressure receiving chamber 36, the equilibrium chamber 38, and the orifice passage 44 in a predetermined incompressible fluid. A predetermined incompressible fluid such as water, polyalkylene glycol, silicone oil, etc. is sealed.

Accordingly, the inner and outer cylindrical fittings 10, 12
In between, when the vibration loads in the eccentric direction are input, the pressure receiving chamber 36 and the equilibrium chamber 38 are adjusted based on the fluid pressure change in the pressure receiving chamber 36 generated by the elastic deformation of the rubber elastic body 14. The fluid flow through the orifice passageway 44 created between the two constitutes a fluid flow mechanism capable of exerting a damping force on input vibrations.

Note that the vibration frequency range in which the vibration damping effect of the fluid flow mechanism can be effectively exhibited, that is, the frequency range in which liquid column resonance is induced, is the orifice passage 44.
This is determined by the length, cross-sectional area, etc. of the vibration, but in this example, it is tuned to about 10Hz, and the vibration is The damping force is set so that it can be effectively applied.

In addition, regarding the mount in this example,
As shown in FIGS. 1 and 3, regulation plates 60 are attached to both ends of the inner cylinder fitting 10 in the axial direction, respectively. This regulation plate 60 is composed of a mounting cylinder part 62 that is externally fitted onto the inner cylinder metal fitting 10, and a plate-like part 64 that has a substantially fan shape and extends in the direction perpendicular to the axis. However, among the rubber elastic bodies 14,
By being positioned substantially parallel to and facing the outside in the axial direction of the portion constituting the axial side wall portion of the pressure receiving chamber 36, the regulating plate 60 can control the axis of the pressure receiving chamber 36. The outward bulge of the rubber elastic body 14 constituting the side wall portion is restricted. In addition, in FIG. 1, the gap between the regulation plate 60 and the rubber elastic body 14 disappears due to the elastic deformation of the rubber elastic body 14 due to the engine load when such a mount is mounted on an actual vehicle. .

That is, by the regulation plate 60,
Between the inner and outer cylindrical fittings 10 and 12, these two fittings 10,
12 approaches the pressure receiving chamber 36 with the pressure receiving chamber 36 in between, the side wall portion of the pressure receiving chamber 36 expands and the pressure receiving chamber 3
6 can be effectively prevented from escaping, and an increase in the flow rate of the fluid flowing through the orifice passage 44, which is caused by such fluctuations in fluid pressure, and vibrations caused by the increase in the flow amount of the fluid can be effectively prevented. This means that the damping force can be improved.

On the other hand, as shown in FIGS. 4 and 5, a stopper block 46 having a substantially longitudinal rectangular cross section is integrally fitted into the center hole 48 of the inner cylindrical fitting 10 in the axial direction. The projecting end portions 50 and 52 on both sides are connected to the pressure receiving chamber 36 and the cavity 20.
They each protrude within the interior at a predetermined height.

When an excessive vibration load is input in the eccentric direction of the inner and outer cylindrical fittings 10 and 12 due to the stopper block 46, the stopper block 4 is caused to protrude into the pressure receiving chamber 36 and the cavity 20.
The protruding ends 50 and 52 of the orifice segment 3
Based on the contact with the inner circumferential surfaces of 0 and 31, excessive displacement of the inner cylindrical fitting 10 and the outer cylindrical fitting 12 in the eccentric direction can be restricted.

Further, in the stopper block 46, a rubber block 53 is provided on the outer circumferential surface of the protruding end 50 protruding into the pressure receiving chamber 36, with a peripheral edge protruding by a predetermined distance from each side surface of the protruding end 50. A rectangular umbrella plate 54 is integrally fixed with bolts.

And the rubber block 5 of this umbrella plate 54
3, the protruding end 50 of the stopper block 46 is brought into contact with the inner circumferential surface of the orifice segment 30, and
A rectangular annular narrowed portion 58 with a predetermined cross-sectional area is formed between the peripheral edge of the rubber block 53 fixed to the umbrella plate 54 and the corresponding inner wall surface of the pressure receiving chamber 36, and the inner tube fitting 10 and the outer tube fitting 10 are connected to each other. 12 are moved relative to each other in their eccentric direction upon vibration input, the incompressible fluid sealed in the pressure receiving chamber 36 is caused to flow (vibrate) in the radial direction of the mount through the narrowed portion 58. The liquid column resonance caused by the flow of the sealed fluid within the narrowed portion 58 can improve the vibration damping function against input vibration in a predetermined frequency range, that is, reduce the mount spring constant. It is becoming.

Note that the vibration frequency range in which the vibration absorption effect due to the liquid column resonance of the sealed fluid can be effectively exhibited is determined by the size of the constricted portion 58, etc., but in particular, in this example, It is set in a high frequency range of ~300Hz, thereby preventing muffled sounds such as engine transmitted sound.

Furthermore, in the case of the mount in this embodiment, as shown in FIG.
A rectangular communication window 68 is provided in a portion where 4 is not formed. On the other hand, as shown in FIG. 8, the outer cylinder fitting 12 is provided with a rectangular cutout window 70 at a portion corresponding to the communication window 68 of the orifice division body 30.
A seal rubber 42 fixed to the inner peripheral surface is exposed to the outside. Then, the seal rubber 4
2, the exposed portion of the cutout window 70 of the outer cylinder fitting 12 is a diaphragm-shaped elastic thin film 72 that swells outward.
As a result, the opening of the communication window 68 of the orifice segment 30 is closed.

Further, the communication window 68 of the orifice divided body 30
As shown in FIG. 2, a partition member 74 is fitted and integrally attached therein, so that between the partition member 74 and the thin part 72 of the seal rubber 42, The partition member 74 forms a sub-chamber 76 that is separated from the pressure-receiving chamber 36 .

Here, the partition members 74 are stacked one on top of the other, so that their opposing inner surfaces are opposed to each other substantially in parallel with a predetermined gap therebetween, and a housing space 78 that extends in the mount circumferential direction is formed therein. It is composed of partition plates 80 and 82, and a movable plate 84 accommodated in the accommodation space 78 in such a manner that the displacement end position is regulated by the opposing inner surfaces of both partition plates 80 and 82. Further, each of the partition plates 80 and 82 is provided with a plurality of through holes 86, and through these through holes 86, the space within the housing space 78 is communicated with the pressure receiving chamber 36 or the sub chamber 76. It is being

Therefore, when vibration in a predetermined frequency range is inputted between the inner and outer cylindrical fittings 10 and 12 by such a partition member 74, the inside of the accommodation space 78 and the pressure receiving chamber 36 are separated based on the displacement of the movable plate 84. The sealed fluid is allowed to flow between the inside of the sub-chamber 76 and the inside of the auxiliary chamber 76, and thereby the liquid pressure inside the pressure-receiving chamber 36 can be absorbed, and as is clear from this, In this embodiment, the partition member 74 constitutes a hydraulic pressure absorption mechanism capable of absorbing an increase in the hydraulic pressure within the pressure receiving chamber 36 when vibrations in a predetermined frequency range are input.

Note that the vibration frequency at which the liquid pressure absorption effect by the partition member 74 can be effectively exhibited, that is, the partition plate 8
The liquid column resonance frequency of the sealed fluid flowing through the through hole 86 is determined depending on the size of the through hole 86, etc., but in particular, in this embodiment, the resonance frequency of the liquid column is approximately 50 to 150 Hz. It will be set in the medium frequency range. Furthermore, if the amount of displacement of the movable plate 84 is large, the vibration damping function of the orifice passage 44 will be inhibited due to the liquid pressure absorption in the pressure receiving chamber 36 based on the displacement of the movable plate 84. For this reason, when a low frequency, large amplitude vibration is input in which damping force by the orifice passage 44 is expected, the amount of displacement needs to be set sufficiently small so that an increase in the hydraulic pressure in the pressure receiving chamber 36 can be ensured.

By the way, in such a mount, generally, as mentioned above, the orifice half bodies 30, 31
After fitting the outer cylindrical fitting 12 onto the vulcanized molded product assembled with the vulcanized molded product and sealing the fluid inside it, in order to ensure sealing between these two members,
The diameter reduction process is performed on the outer cylinder metal fitting 12. In particular, in the case of the mount in this embodiment, after such diameter reduction process is performed, the outer cylinder metal fitting 1
2, a communication hole 88 communicating with the orifice passage 44 is formed.

In other words, due to the communication hole 88, the increase in hydraulic pressure caused by the volume reduction in the pressure receiving chamber 36 and the equilibrium chamber 38 due to the diameter reduction process is prevented by the communication hole 88.
This problem can be solved by removing pressure (liquid removal) through the liquid pressure, and thereby problems such as disappearance of the void space 20 and deterioration of sealing performance caused by such an increase in liquid pressure can be effectively avoided. It will become.

In addition, after the pressure is released from the communication hole 88,
It is closed liquid-tightly by blind rivets 90 or the like.

Therefore, in the engine mount of this embodiment having the above-described structure, when low frequency and large amplitude vibrations of around 10 Hz are input, based on the fluid flow through the orifice passage 44, While an excellent damping force can be exerted, the resistance to the fluid flowing through the orifice passage 44 increases, and when a small amplitude vibration in the medium frequency range of 50 to 150 Hz is input, the resistance to the fluid flowing through the orifice passage 44 increases. Based on the displacement of the movable plate 84 in the mechanism, an increase in the hydraulic pressure in the pressure receiving chamber 36 is avoided, and low dynamic spring characteristics can be exhibited. When a small amplitude vibration in a high frequency range is input, low dynamic spring characteristics can be exhibited based on the flow of fluid through the constricted portion 58 (liquid column resonance).

In other words, with such an engine mount, high damping characteristics against input vibrations in the low frequency range as well as low dynamic spring characteristics against input vibrations in the medium to high frequency range can be advantageously realized over a wider frequency range. This not only prevents input vibrations in the low frequency range such as engine shake, but also prevents vibrations in the medium to high frequency range that cause muffled noise such as mid-speed muffled noise, beat sound, and muffled noise such as engine transmission sound. Input vibration isolation can be achieved extremely effectively.

In addition, in the engine mount according to this embodiment, the increase in hydraulic pressure in the pressure receiving chamber 36 and the equilibrium chamber 38 caused by the diameter reduction of the outer cylinder fitting is caused by pressure relief through the communication hole 88. Therefore, deterioration of spring characteristics and deterioration of sealing performance and durability due to the disappearance of void space 20 can be advantageously avoided.

Furthermore, in the engine mount of this embodiment, the regulation plates 60 prevent the rubber elastic body 14 forming the axial side wall portion of the pressure receiving chamber 36 from expanding outward when vibration is input. Therefore, it also has the advantage that the damping function of the orifice passage 44 against input vibrations in the low frequency range can be more effectively exhibited.

Next, FIGS. 9 to 11 respectively show other embodiments of engine mounts constructed according to the present invention.

It should be noted that these embodiments show other aspects of the hydraulic pressure absorption mechanism with respect to the engine mount in the first embodiment, and have the same structure as the first embodiment. For parts that have
By assigning the same reference numerals to each, detailed explanation thereof will be omitted.

First, in the engine mount shown in FIG. 9, the above-mentioned partition member 74 is not disposed with respect to the communication window 68 formed in the orifice divided body 30, and the opening thereof is not provided. A portion of the covering rubber seal 42 corresponding to the communication window 68 is made of an elastic thin film 92 containing a reinforcing material such as canvas.

In other words, the elastic thin film 92 is deformed in response to fluctuations in the fluid pressure within the pressure receiving chamber 36 caused by vibration input, thereby making it possible to avoid an increase in the fluid pressure within the pressure receiving chamber 36. ,
As is clear from this, in this embodiment, the elastic thin film 92 constitutes a hydraulic pressure absorption mechanism.

It should be noted that, of course, the size etc. of the elastic thin film 92 are set according to the target vibration frequency to achieve low spring characteristics. The amount of deformation of 92 is regulated to a small value by the reinforcing material, thereby greatly affecting the vibration damping characteristics based on the fluid flow through the orifice passage 44 when large amplitude vibrations in the low frequency range are input. Therefore, it is possible to effectively avoid an increase in the hydraulic pressure in the pressure receiving chamber 36 when a vibration with a small amplitude in the medium frequency range is input, and to reduce the spring constant accordingly.

Next, in the case of the engine mount shown in FIG. 10, a canvas or the like is used to cover the radially inward opening of the communication window 68 formed in the orifice split body 30. An elastic thin film 94 whose deformation is regulated by a reinforcing material is integrally vulcanized and bonded.

That is, in this embodiment as well, similar to the elastic thin film 92 in the second embodiment, the elastic thin film 94 constitutes a hydraulic pressure absorption mechanism, and the elastic thin film 94 absorbs vibrations. By being deformed in accordance with the fluid pressure fluctuations within the pressure receiving chamber 36 that occur upon input, such an increase in the fluid pressure within the pressure receiving chamber 36 can be avoided.

In addition, in the mount in this embodiment, the communication window 6 to which the elastic thin film 94 is fixed is
It is not necessary to close the outer opening of the elastic thin film 9 with the seal rubber 42.
Since it is structurally difficult to ensure sufficient sealing performance for the pressure receiving chamber 36 in the outer space of 4, a fluid is sealed in the space 96 and the space 96 is closed off with the sealing rubber 42. That is desirable.

When the fluid is sealed in the space 96 in this way, the elastic thin film 94 is prevented from increasing the fluid pressure in the pressure receiving chamber 36 by elastic deformation of the seal rubber 42 in the radial direction. This means that a predetermined amount of deformation of can be allowed.

Furthermore, in the case of the engine mount shown in FIG. 11, a piece of canvas or the like is placed over the communication window 68 formed in the orifice split body 30 so as to cover the opening on the radially inward side of the communication window 68. Elastic thin film 94 whose deformation is regulated by embedding reinforcing material
are integrally vulcanized and bonded, and a space formed between the elastic thin film 94 and the seal rubber 42 is communicated with the orifice passage 44, and a fluid is sealed therein.

That is, in this embodiment, as in the third embodiment, the elastic deformation of the seal rubber 42 in the radial direction causes the pressure receiving chamber 36 in the elastic thin film 94 to
A predetermined amount of deformation is allowed in order to avoid an increase in the hydraulic pressure inside, and as is clear from this, the elastic thin film 94 constitutes a hydraulic pressure absorption mechanism. -ing

Although several embodiments of the present invention have been described in detail above, these are literal illustrations, and the present invention is not to be construed as being limited to such specific examples.

For example, the specific structure of the hydraulic pressure absorption mechanism in the bushing according to the present invention is not limited to that of the embodiment described above, and in particular, in the embodiment described above, the movable plate 84 constituting the hydraulic pressure absorption mechanism Although the elastic thin films 92 and 94 are formed to have a rectangular planar shape, it is easy to change the shape to another shape such as a circular shape.

Further, in all of the above embodiments, the outer cylinder fitting 12 is provided with a cutout window 70 through which the seal rubber 42 or the elastic thin film 92 can bulge out. If an air chamber defined by an elastic thin film is provided for the pressure receiving chamber 36 and a structure is adopted in which the elastic thin film is allowed to deform (bulge) in the air chamber, such a notch window 7
0 does not necessarily need to be provided.

Furthermore, in the above embodiment, the outer cylinder fitting 12
The communication hole 88 provided in the cylindrical hole 88 was designed to prevent an increase in the hydraulic pressure within the pressure receiving chamber 36 and the equilibrium chamber 38 due to the diameter reduction process. 12, a single or plural communication holes 88 are provided in advance, and after the diameter is reduced, fluid is sealed through the communication holes 88 to avoid an increase in hydraulic pressure. It is also possible to do so.

However, such a communication hole 88 does not need to be particularly provided when the ability of the equilibrium chamber 38 etc. to avoid a rise in hydraulic pressure is large, and is not an essential requirement in the present invention.

Further, in the above embodiment, a specific example of the present invention was shown in a mount having two fluid chambers consisting of a pressure receiving chamber 36 into which vibrations are input and an equilibrium chamber 38 whose volume is variable. But other than that,
For example, as shown in the above-mentioned Utility Application No. 61-100614, there is a mount having a structure in which two pressure receiving chambers into which vibration is input are radially opposed to each other with an inner cylinder fitting in between, and The present invention can also be successfully applied to mounts with three or more fluid chambers.

In addition, in the above embodiment, an example was described in which the present invention was applied to a cylindrical engine mount for a front-wheel drive vehicle, but the present invention can also be applied to anti-vibration bushings and anti-vibration mounts such as suspension bushings of automobiles. Of course, it can be suitably applied.

In addition, although not listed one by one, the present invention may be implemented with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and such embodiments may include the present invention. It goes without saying that any of these are included within the scope of the present invention as long as they do not deviate from the spirit of the invention.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an engine mount as an embodiment of the present invention, FIG. 2 is a cross-sectional view in FIG. 1, FIG. 3 is a right side view in FIG. Figure 4 shows an integrally vulcanized product of rubber elastic body in such an engine mount.
1, FIG. 5 is a cross-sectional view of FIG. 4, FIG. 6 is a cross-sectional view of FIG. 5, and FIG. 7 is an orifice half used in such an engine mount. FIG. 8 is a plan view showing the split body, and FIG. 8 is an enlarged view taken along the line A-A in FIG. 2. Further, FIGS. 9 to 11 are cross-sectional views corresponding to FIG. 2, respectively, showing other embodiments of the engine mount having a structure according to the present invention. 10...Inner cylinder metal fitting, 12...Outer cylinder metal fitting, 14...
... Rubber elastic body, 36 ... Pressure receiving chamber, 38 ... Equilibrium chamber, 42 ... Seal rubber, 44 ... Orifice passage, 46 ... Stopper block, 54 ... Umbrella plate, 58 ... Constriction section, 68 ... Communication window , 70...
... cutout window, 74 ... partition member, 84 ... movable plate,
86... Through hole, 88... Communication hole, 90... Blind rivet, 92, 94... Elastic thin film.

Claims (1)

[Claims for Utility Model Registration] (1) An inner cylindrical metal fitting and an outer cylindrical metal fitting arranged concentrically or eccentrically with each other are connected by a cylindrical rubber elastic body interposed between them, A plurality of fluid chambers, which constitute a connecting body and which are filled with a predetermined incompressible fluid and communicated with each other through an orifice passage, are provided in a circumferentially divided state; At least one of the fluid chambers into which vibrations to be damped are input is provided with a constriction that is integrally attached to the inner cylindrical metal fitting or the outer cylindrical metal fitting and between the inner wall surface of the fluid chamber and the inner cylindrical metal fitting. In the fluid-filled vibration-isolating bushing, the fluid-filled vibration isolating bushing is provided with an umbrella member that forms an inner wall surface of the fluid chamber, and a movable member or is equipped with an elastic member, and the movable member or the elastic member is displaced or deformed by a predetermined amount in the radial direction of the bush, thereby absorbing the increase in liquid pressure when vibration is input in the fluid chamber. A fluid-filled anti-vibration bushing characterized by the provision of a mechanism. (2) The outer cylindrical fitting is provided with a sealable communication hole that communicates with the fluid chamber, and the communication hole removes or prevents fluid pressure in the fluid chamber under a non-loaded state. A fluid-filled anti-vibration bushing according to claim 1, which is constructed so as to be able to perform the following functions.