JPH01224544A - Fluid seal type vibrationproof device - Google Patents

Abstract

PURPOSE:To obtain the titled device which is lightweight and possesses the superior vibration absorbing characteristic at a low cost by forming a partitioning wall for the dividing into a main fluid chamber and a subfluid chamber of a fluid seal type vibrationproof device by baking-fitting a rubber onto a base plate consisting of thin metal plates. CONSTITUTION:An upper plate 12 on which an upper orifice 17 and an orifice 24 for low frequency region is formed by baking-fitting a rubber 11 onto a base plate 10 consisting of a thin steel plate. Therefore, each effective sectional shape of the orifices 17 and 24 is determined correctly by the opened ports 14 and 15 formed on the base plate 10. Further, since the shape in the direction of length of the orifice 17, 24 can be secured by the rubber 11 which is easily shaped, the shaping to a complicate shape having a taper, etc., is facilitated. Further, the part between the upper orifices 17 and 17 or the part between the orifices 17 and 24 can be formed thin, and the total sectional area can be increased by increasing the number of orifices for intermediate or high frequency region. The rigidity of a partitioning wall 6 can be secured by the base plate 10 and a lower plate 13.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a vibration isolating device used in an automobile engine mount, etc., and in particular, the present invention relates to a vibration isolating device used in an automobile engine mount, etc. The present invention relates to a fluid-filled vibration isolator that includes a fluid-filled vibration damping device.

(Prior Art) A variety of vibrations with different frequencies and amplitudes are generated in an automobile depending on its operating conditions, such as the engine speed and the condition of the road surface. Therefore, it is necessary for automobiles to use vibration isolators that can absorb vibrations over a wide range.

In such a vibration isolator, a main fluid chamber is formed by an elastic body such as rubber whose both ends are fixed to a mounting member to which a vibrating body such as an engine is attached and a support member which is attached to a support body such as a vehicle body frame. Additionally, a fluid-filled vibration damping device is known in which a sub-fluid chamber is provided which communicates with the main fluid chamber through an orifice, and an incompressible fluid such as water or oil is sealed in the main and sub-fluid chamber.

In such a fluid-filled vibration damping device, the main fluid chamber and the sub-fluid chamber are generally separated by a partition wall, and an orifice is formed in the partition wall to communicate between the main and sub-fluid chambers. .

According to such a fluid-filled vibration damping device, vibrations from an engine or the like are absorbed by the elastic deformation of the elastic body and the flow of fluid through the orifice.

By the way, in such a fluid-filled vibration isolator,
It is known that by causing resonance in the fluid flowing through the orifice, it is possible to increase the loss coefficient, that is, the damping coefficient, and reduce the dynamic spring constant at the target vibration frequency (for example, 1986
(Refer to Publication No.-263736). In order to cause the fluid to resonate in this way, it is necessary to form the orifice in various shapes. Further, in order to provide sufficient mass to the fluid flowing through the orifice, it is necessary to make the orifice long. That is, the partition wall in which the orifice is formed must be thick. Furthermore, the partition wall must have sufficiently high rigidity so as not to be deformed by the fluid pressure generated in the fluid chamber.

For this reason, in conventional fluid-filled vibration damping devices, the partition wall that partitions the main fluid chamber and the sub-fluid chamber is a cast iron component formed by casting.

(Problems to be Solved by the Invention) However, such a partition wall made of cast iron inevitably increases in weight.

Furthermore, in recent years, the shape of orifices has become increasingly complex in order to minimize the resistance applied to the fluid flowing through the orifices. Furthermore,
In order to be able to absorb even low-frequency, large-amplitude vibrations, it has become necessary to provide a separate narrow and long orifice. Therefore, a problem arises in that the mold for casting the partition wall becomes extremely complicated and the cost increases. In addition, thin wall portions may occur in the partition walls, which cannot be handled by casting.

The present invention was made in view of these problems, and its purpose is to make a partition wall lightweight and easy to mold, thereby making it lightweight, inexpensive, and with excellent vibration absorption properties. It is an object of the present invention to provide a fluid-filled vibration damping device.

(Means for Solving the Problems) In order to achieve this object, in the present invention, a partition wall that partitions a main fluid chamber and a sub-fluid chamber of a fluid-filled vibration isolator is made of a base plate made of a thin metal plate. It is formed by baking rubber.

(Function) With this configuration, the cross-sectional shape and diameter of the orifice can be accurately determined by the opening formed in the metal base plate. In addition, the rigidity of the partition wall
Its base is secured by provisional.

In addition, since rubber is easy to mold, complex-shaped orifices can be easily formed, and post-molding operations such as removing burrs are also easier, which makes it possible to reduce costs. Become.

Furthermore, since rubber is lightweight, the partition wall whose thickness is ensured by rubber is lightweight, and a lightweight fluid-filled vibration damping device can be obtained.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

In the drawings, FIG. 1 is a longitudinal cross-sectional view showing an automobile engine mount which is an embodiment of the fluid-filled vibration isolator according to the present invention, and FIGS. 2 and 3 are views showing the engine mount used in the engine mount. FIG. 2 is a vertical cross-sectional view and a plan view of a partition wall.

As is clear from FIG. 1, this engine mount 1 includes a conical cylindrical elastic body 2 made of thick rubber and a housing 3 made of a rigid material such as a steel plate. The housing 3 is composed of an upper housing 3a and a lower housing 3b having a substantially cylindrical shape, and is attached to a vehicle body frame as a support by a flange 3c provided on the lower housing 3b. Therefore, in this embodiment, the housing 3 constitutes a support member.

The external lower end of the elastic body 2 is vulcanized and baked onto the inner peripheral surface of the upper end of the upper housing 3a. Further, on the upper end of the elastic body 2, a mounting fitting 5, that is, a mounting member, is vulcanized and baked, which is equipped with a bolt 4 for fixing the engine, which is a vibrating body. In this way, the engine is supported by the vehicle body frame via the elastic body 2, and the elastic body 2 is elastically deformed in response to the vibrations.

A partition wall 6 is provided below the elastic body 2 to cover the lower opening of the elastic body 2. Further, on the lower surface side of the partition wall 6, a rubber diaphragm 7 having a thin portion that easily deforms is provided. The partition wall 6 and the diaphragm 7 are constructed by sandwiching the mounting flanges 6a and 7a on their peripheral edges between the lower end of the upper housing 3a and the upper end of the lower housing 3b, and caulking the lower end of the upper housing 3a. It is now fixed to . In that case, there is a liquid-tight seal between them.

In this way, the inside of the engine mount 1 is surrounded by the elastic body 2 and the diaphragm 7, and the partition wall 6
A liquid-tight space is formed which is divided into upper and lower parts. In the space, an incompressible fluid such as oil or water is sealed. That is, the spaces above and below the partition wall 6 are respectively defined as fluid chambers 8.9.

A fluid chamber 8 formed above the partition wall 6 is surrounded by an elastic body 2, and its volume is changed by deformation of the elastic body 2 due to engine vibration. That is, the fluid chamber 8 is the main fluid chamber. On the other hand, a sub-fluid chamber 9 formed below the partition wall 6 is surrounded by a diaphragm 7 that can be easily deformed. The lower surface side of the diaphragm 7 is open to the atmosphere. Therefore, the auxiliary fluid chamber 9 has a diaphragm 7 depending on the internal fluid pressure.
By deforming, the volume can be changed freely.

As is clear from FIG. 2.3, the partition wall 6 is shaped like a relatively thick disk and has a mounting flange 6a at its peripheral edge. This partition wall 6 includes an upper plate 12 in which rubber 11 is vulcanized and baked on a base plate 10 made of a thin steel plate;
The lower plate 13 is made of a thin steel plate.

The base plate 10 constituting the upper plate 12 is shaped like a hat having a flange at its peripheral edge, and has a large number of circular openings 14, 14°, . . . formed in its center. Moreover, one rectangular opening 15 is formed on the top side.

The rubber 11 is filled in the recess on the lower side of the center of the base plate 10 to form a rubber layer. The rubber layer 11 has an opening 14 in the base plate 10. '
14. A large number of communicating holes 16, 16 . ...
is formed.

The communication hole 16 has a tapered portion that widens toward the lower end. In this way, a relatively long upper orifice 17 that vertically penetrates the upper plate 12 is formed by the openings 14 in the base plate 10 and the communication holes 16 in the layer of rubber 11.

Further, on the lower surface of the rubber layer 11, an arcuate groove 1 is formed at the periphery.
8 is formed, and a circular recess 19 is formed in the center. One end of the groove 18 is connected to a rectangular opening I5 formed on one side of the base plate 10. Also,
The recess 19 is connected to the communication holes 16, 16 . ... is sized to completely include the opening area. The rubber 11 further includes:
The stopper 21 is made to protrude toward the upper surface of the outer circumference of the base plate 10 through an opening 20 formed around the top of the base plate 10, and the protrusion forms a stopper 21 that restricts excessive deformation of the elastic body 2. .

On the other hand, the lower plate 13 has upper orifices 17, 17. ..., that is, the openings 14, 14 of the base plate 10. ...and communication hole 16 in the rubber layer
,16. A lower orifice 22° 22, . . . having a tapered portion whose diameter decreases downward and having an open lower end is formed at a position opposite to . The opening diameter of the lower orifice 22 is relatively large.

Further, a rectangular opening 23 is formed on one side of the lower plate 13 and faces the other end of the arcuate groove 18 formed on the outer periphery of the lower surface of the rubber layer 11 .

The partition wall 6 has an upper plate 1 attached to this lower plate 13.
It is formed by overlapping 2 and welding the peripheral edges. The upper orifice 17 of the upper plate 12 and the lower orifice 22 of the lower plate 13
A rectangular opening 15 formed in the base plate 1o of the upper plate 12, a groove 18 formed in the layer of rubber 11, and a rectangular opening formed in the lower plate 13 form an orifice for medium and high frequency ranges. 23 forms an orifice 24 for low frequency range that communicates the main fluid chamber 8 and the sub fluid chamber 9.

Further, a thin disc-shaped space is formed between the upper plate 12 and the lower plate 13 by a recess 19 formed on the lower surface of the layer of rubber 11. A thin disc-shaped diaphragm 25 is housed in the space. The thickness of the accommodating cavity of this diaphragm 25,
That is, the depth is smaller than the depth of the recess 19 formed in the layer of rubber 11. Therefore, the diaphragm 25
can move up and down between the lower surface of the upper plate 12 and the upper surface of the lower plate 13. Moreover, the fluid pressure in the main fluid chamber 8 acts on the upper surface of the diaphragm 25 through the upper orifice 17, and the fluid pressure in the auxiliary fluid chamber 9 acts on the lower surface thereof through the lower orifice 22. ing.

Next, the operation of the engine mount 1 configured as described above will be explained.

When the engine rotates at medium to high speeds, such as during normal driving of an automobile, small amplitude vibrations at medium to high frequencies are input to the engine mount 1 . Therefore, the elastic body 2 is slightly deformed. As a result, the volume of the main fluid chamber 8 changes, and its internal pressure changes. The pressure change passes through the seven orifices 17 of the partition wall 6 to the upper plate 12 and lower plate 13.
The change in volume of the main fluid chamber 8 is absorbed by the diaphragm 25 provided in the space vibrating up and down in accordance with the pressure change. At this time,
As the diaphragm 25 vibrates, the fluid flows through the lower orifice 22 and the pressure inside the sub-fluid chamber 9 changes.
The pressure change is absorbed by the change in volume of the sub-fluid chamber 9 due to the deformation of the diaphragm 7.

In this way, the deformation of the elastic body 2 due to the vibration of the diaphragm 25 is allowed with almost no resistance, and the vibration at that time is absorbed by the elasticity of the elastic body 2. When the elastic body 2 resonates with engine vibration,
The resonance amplitude of the elastic body 2 is suppressed by resonating the vibration of the fluid flowing through the upper orifice 17 with a predetermined phase difference.

Furthermore, when vibrations with extremely large amplitudes occur, such as during cranking of the engine or during shaking during normal driving, the elastic body 2 deforms significantly, and the volume of the main fluid chamber 8 changes significantly. In such a case, the change in volume due to the vertical movement of the diaphragm 25 is not absorbed. Therefore, the fluid flows through the thin and long orifice 24 for low frequency range, and vibrations are damped by the flow resistance.

In this way, in order for the fluid flowing through the orifice 17 to resonate at a predetermined frequency, the orifice 1
It is necessary to accurately set the effective cross-sectional shape of 7 and to make its length sufficiently long. In addition, in order to allow the deformation of the elastic body 2 without resistance during vibration in the medium and high frequency range, the total cross-sectional area of the upper orifice 17 and the lower orifice 22 that constitute the orifice for the medium and high frequency range is sufficient. The orifice must be large enough to reduce the flow resistance of the fluid flowing through the orifice. Therefore, if the orifices 17, 22 are to have a small diameter, it is necessary to increase their number.

Furthermore, in order to prevent the formation of vortices or the like in the fluid flowing between these orifices 17.22 and the cavity in which the diaphragm 25 is accommodated, these orifices 17.
It is also necessary to form 22 into a tapered shape.

On the other hand, the low frequency orifice 24 is required to have a small cross-sectional area and an extremely long length in order to provide sufficient attenuation to the fluid flowing therethrough.

In the case of this engine mount 1, the upper plate 12 on which the upper orifice 17 and the low-frequency orifice 24 are formed is made by baking the rubber 11 onto the base plate 10 made of a thin steel plate.
The effective cross-sectional shape of 24 can be precisely defined by the openings 14.15 formed in the base plate 10. Also,
Since the shape of the orifice 17, 24 in the longitudinal direction is ensured by the easily moldable rubber 11, it is easy to form it into a complex shape with a taper or the like. Furthermore, since it is possible to form a thin wall between the upper orifices 17 and 17 or between orifices 17 and 24, it is also possible to increase the total cross-sectional area by increasing the number of orifices for medium and high frequency ranges. .

The rigidity of the partition wall 6 is determined by the base plate 10 made of a steel plate.
and secured by the lower plate 13. In addition, since the thickness is ensured by the rubber 11, the partition wall 6 can be lightweight but have a long orifice 17.24.

Furthermore, the rubber 11 is attached to the base plate 10 made of a steel plate in this way.
By forming the upper plate 12 by baking it, it becomes possible to integrally provide the stopper 21 made of the rubber 11 on the outer periphery of the upper surface thereof. By providing such a stopper 21, the inner surface of the elastic body 2 comes into contact with the stopper 21 during large-amplitude vibrations, so excessive deformation of the elastic body 2 is regulated, and the mounting bracket 5 is attached to the partition wall. This prevents the partition wall 6 from being damaged due to contact with the partition wall 6. Furthermore, since the space between the upper plate 12 and the lower plate 13 is sealed by the rubber 11,
There is no need to use a separate sealing member. A sealing member that seals between the upper plate 12 and the housing 3 also includes:
It can be formed integrally with the upper plate 12 using the rubber 11. Therefore, it is possible to reduce the number of parts.

FIG. 4 is a longitudinal sectional view showing another example of the partition wall 6 used in the engine mount 1 as shown in FIG. In this embodiment, the same reference numerals are given to the parts corresponding to the parts of the partition wall 6 in FIGS. 2-3.

In the partition wall 6 of FIG. 4, the upper plate 12 is similar to that of FIG. 2.3. Similarly to the upper plate 12, the lower plate 13 is made by vulcanizing and baking rubber 31 on a base plate 3o made of a thin steel plate.

That is, the base plate 30 has a thin plate-like shape with a flange on the periphery, and has a large number of circular openings 34, 34. ... is formed. Further, a rectangular opening 35 is formed on one side of the bottom surface of the upper plate 12, which is connected to the other end of the groove 18 formed on the outer circumference of the lower surface of the upper plate 12. The rubber 31 is filled in the recess of the base plate 30,
A rubber calendar has been formed. The rubber layer 31 has openings 34, 34, . ...
A large number of communicating holes 36.36. ... is formed. The upper end of the communication hole 36 is opened to the upper surface of the layer of rubber 31, and a tapered portion that widens upward is formed at the upper end. In this way, the lower orifice 22 that vertically penetrates the lower plate 13 is formed by the openings 34 of the base plate 30 and the communicating holes 36 of the layer of rubber 31.

The other configurations are similar to those shown in FIG. 2.3.

In the fluid-filled engine mount 1 having the partition wall 6 as shown in FIG. 4, the lower orifice 22 provided in the lower plate 13 also has an accurate cross-sectional shape and sufficient length. The fluid flowing through the orifice 22 can also be caused to resonate. Therefore, fluid resonance occurs in the entire middle and high frequency range orifice consisting of the upper orifice 17 and the lower orifice 22, and the resonance of the elastic body 2 is suppressed more reliably.

Further, in the case of this partition wall 6, the entire circumference of the space in which the diaphragm 25 vibrates is formed by the rubbers 11 and 31. Therefore, when the diaphragm 25 vibrates, the diaphragm 25
comes into contact with the rubber 11°31, thereby reliably preventing the occurrence of hitting sounds.

In the above embodiment, the diaphragm 25 is provided inside the partition wall 6.
However, the present invention is not limited to this, and can also be applied to an engine mount in which vibrations are absorbed only by the orifice.

In such a case, the lower plate 13 may be omitted.

Further, the present invention is not limited to the automobile engine mount as in the above embodiment, but can also be applied to various fluid-filled vibration damping devices, such as suspension mounts.

(Effects of the Invention) As is clear from the above description, according to the present invention, the partition wall provided between the main fluid chamber and the sub-fluid chamber, in which the orifice communicating therebetween is formed, is made of a thin metal plate. Since rubber is baked onto the base plate, the thickness of the partition wall is ensured by the rubber, and the partition wall can be thick while being lightweight.

Therefore, the orifice formed in the partition wall can be made sufficiently long. Furthermore, since rubber is easy to mold, it is also easy to form an orifice with a complicated shape. Furthermore, the work of removing burrs becomes easier and there is no need to process the attachment surface to the support member, etc., so the work required after molding is reduced and costs are reduced.

Further, since the rubber stopper, seal member, etc. can be integrally molded, the number of parts can be reduced. When a diaphragm is provided inside the partition wall, the diaphragm can be held by rubber, so that it is also possible to prevent the generation of knocking noise due to the vibration of the diaphragm.

Therefore, the degree of freedom in design is increased, and a fluid-filled vibration isolator with excellent vibration absorption characteristics can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a fluid-filled vibration isolator according to the present invention, FIG. 2 is an enlarged vertical cross-sectional view showing a partition wall used in the vibration isolator, and FIG. is a plan view of the partition wall, and FIG. 4 is a longitudinal sectional view similar to FIG. 2 showing another example of the partition wall. 1... Engine mount (fluid-filled vibration isolator) 2... Elastic body 3... Housing (supporting member) 5... Mounting bracket (mounting member) 6... Partition wall 7... Diaphragm 8
...Main fluid chamber 9...Sub-fluid chamber 10...
・Base plate 11...Rubber 12...Upper plate 13...Lower plate 17...Upper orifice 19...Concavity (diaphragm accommodation space) 21...Stopper 22...Lower orifice 24 ... Orifice for low frequency range 25 ... Vibration plate

Claims (4)

[Claims] (1) A mounting member to which the vibrating body is attached, a support member arranged at a distance from the mounting member and attached to the support body, and both ends of which are fixed to the mounting member and the support member respectively, and a main fluid chamber inside. an elastic body that forms an elastic body; a sub-fluid chamber that communicates with the main fluid chamber via an orifice and whose volume changes according to changes in the volume of the main fluid chamber; and the main fluid chamber and the sub-fluid. A fluid-filled vibration damping device, comprising: a partition wall provided between the main and sub-fluid chambers, and a partition wall in which the orifice is formed; and a fluid is sealed in the main sub-fluid chamber; A fluid-filled vibration isolator formed by baking rubber onto a base plate. (2) the partition wall is provided with a cavity that communicates with the main fluid chamber and the auxiliary fluid chamber through orifices, and within the cavity, the fluid pressure in the main and auxiliary fluid chamber acts on both sides, respectively; The fluid-filled vibration isolator according to claim 1, further comprising a diaphragm that vibrates as the fluid pressure changes. (3) The fluid-filled vibration damping device according to claim 2, wherein the orifice that communicates the cavity with the main and sub-fluid chambers includes a tapered portion that widens toward the cavity. (4) The rubber forming the partition wall is located on the outer periphery of the base plate, and when the elastic body deforms significantly toward the partition wall, the inner surface of the elastic body comes into contact with the rubber, causing the elastic body to 2. The fluid-filled vibration damping device according to claim 1, wherein a stopper for regulating excessive deformation is integrally formed.