JP2671001B2 - Fluid filled type vibration damping device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration device for use in an automobile engine mount or the like, and particularly to a fluid chamber inside a fluid chamber formed by an elastic body such as rubber. The present invention relates to a fluid-filled type vibration damping device in which is enclosed.

(Prior Art) Various vibrations having different frequencies and amplitudes are generated in an automobile depending on its operating state, for example, the engine speed and the state of the road surface on which the vehicle travels. Therefore, it is necessary to use an anti-vibration device capable of absorbing a wide range of vibrations in an automobile.

As such a vibration isolation device, 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 vibration body such as an engine is mounted and a support member to be mounted to a support body such as a vehicle body frame. At the same time, there is known a fluid filled type vibration damping device in which an auxiliary fluid chamber communicating with the main fluid chamber via an orifice is provided, and an incompressible fluid such as water or oil is enclosed in the auxiliary fluid chamber. In such a fluid-filled type vibration damping device, generally, the main fluid chamber and the sub-fluid chamber are partitioned by a partition wall, and the partition wall is formed with an orifice for communicating between the main and sub-fluid chambers.

According to such a fluid filled type vibration damping device, the vibration of the engine or the like is absorbed by the elastic deformation of the elastic body and the flow of the fluid through the orifice.

By the way, in such a fluid filled type vibration damping device, the loss coefficient at the target vibration frequency, that is, the damping coefficient is increased and the dynamic spring constant is reduced by causing the fluid flowing through the orifice to resonate. It is known that the
60-263736). In order to cause the fluid to resonate, it is necessary to form the orifice in various shapes. Further, in order to give the fluid flowing through the orifice a sufficient mass, 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 a sufficiently high rigidity so that it will not be deformed by the fluid pressure generated in the fluid chamber.

For this reason, in the conventional fluid filled type vibration damping device, the partition wall that divides the main fluid chamber and the sub fluid chamber is a cast iron part formed by casting.

(Problems to be Solved by the Invention) However, in such a cast iron partition wall, an increase in weight is inevitable.

Recently, in order to minimize the resistance applied to the fluid flowing through the orifice,
The shape of the orifice is becoming more and more complicated. Further, in order to absorb low-frequency, large-amplitude vibrations, it is also required to provide a thin and long separate orifice. Therefore, the mold for casting the partition wall is remarkably complicated and the cost is increased. Further, a thin wall portion may be formed on the partition wall, and it may not be possible to cope with the problem by casting.

The present invention has been made in view of such a problem, and an object thereof is to make the partition wall lightweight and easy to mold, so that it is lightweight and inexpensive, and has excellent vibration absorption characteristics. Another object of the present invention is to provide a fluid filled type vibration damping device.

(Means for Solving the Problem) In order to achieve this object, in the present invention, a partition wall for partitioning a main fluid chamber and a sub fluid chamber of a fluid filled type vibration damping device is provided.
The base plate made of a thin metal plate is formed by baking rubber.

(Operation) 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. Further, the rigidity of the partition wall is also ensured by the base plate.

Since the rubber is easily molded, the orifice having a complicated shape can be easily formed, and the post-molding work such as the removal of burrs can be facilitated, so that the cost can be reduced. Become.

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

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In the drawings, FIG. 1 is a vertical sectional view showing an automobile engine mount which is an embodiment of a fluid filled type vibration damping device according to the present invention, and FIGS. 2 and 3 are used for the engine mount. It is a vertical cross-sectional view and a top view of a partition wall.

As is apparent from FIG. 1, the 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 a substantially cylindrical upper housing 3a and a lower housing 3b, 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 outer periphery of the lower end portion of the elastic body 2 is vulcanized and baked onto the inner peripheral surface of the upper end portion of the upper housing 3a. In addition, a mounting member 5 provided with a bolt 4 for fixing an engine, which is a vibrating body, that is, a mounting member is vulcanized and baked on the upper end of the elastic body 2. In this way, the engine is supported by the body frame via the elastic body 2, and the elastic body 2 is elastically deformed in response to the vibration.

Below the elastic body 2, a partition wall 6 that covers the lower surface opening of the elastic body 2 is provided. Further, on the lower surface side of the partition wall 6, a rubber diaphragm 7 having a thin portion that is easily deformed is provided. The partition wall 6 and the diaphragm 7 are formed by narrowing the mounting flanges 6a, 7a on the periphery of the partition wall 6 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 fixed to 3. In that case, a liquid-tight seal is provided between them.

In this way, a liquid-tight space surrounded by the elastic body 2 and the diaphragm 7 and vertically partitioned by the partition wall 6 is formed inside the engine mount 1. An incompressible fluid such as oil or water is enclosed in the space. That is, the spaces above and below the partition wall 6 are fluid chambers 8 and 9, respectively.

The fluid chamber 8 formed above the partition wall 6 is surrounded by the 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, the partition wall 6
The sub-fluid chamber 9 formed below is surrounded by a diaphragm 7 which can be easily deformed. The lower surface side of the diaphragm 7 is open to the atmosphere. Therefore, the volume of the sub-fluid chamber 9 is freely changed by the deformation of the diaphragm 7 according to the fluid pressure inside.

As is clear from FIGS. 2 and 3, the partition wall 6 is a relatively thick disc-shaped member having a mounting flange 6a at the peripheral edge. The partition wall 6 is a base plate 10 made of a thin steel plate.
It is composed of an upper plate 12 obtained by vulcanizing and baking a rubber 11 and a lower plate 13 made of a thin steel plate.

The base plate 10 that constitutes the upper plate 12 is formed in a hat shape having a brim at the peripheral edge, and a large number of circular openings 14, 14, ... Are formed in the center thereof. Further, one rectangular opening 15 is formed on one side of the top. Rubber 11
Is filled in the recess on the lower surface side of the central portion of the base plate 10,
It is designed to form a rubber layer. And that rubber
In the 11th layer, a large number of communication holes 16, 16, ... Which are continuous with the openings 14, 14 ,. The communication hole 16 has a tapered portion that expands toward the lower end side. Thus, the opening 14 of the base plate 10 and the communication hole 16 in the layer of the rubber 11 form a relatively long upper orifice 17 which vertically penetrates the upper plate 12.

Furthermore, on the lower surface of the rubber 11 layer, an arc-shaped groove 18 is formed in the peripheral portion.
Is formed, and a circular concave portion 19 is formed in the central portion.
One end of the groove 18 is connected to a rectangular opening 15 formed on one side of the base plate 10. In addition, the concave portion 19,
It is sized to completely include the area where the communication holes 16, 16 ,. The rubber 11 is further made to project to the upper surface side of the outer peripheral portion of the base plate 10 through an opening 20 formed in the periphery of the top of the base plate 10, and the protruding portion regulates excessive deformation of the elastic body 2. 21 are formed.

On the other hand, in the lower plate 13, the upper orifices 17, 17, ... Of the upper plate 12, that is, the openings 14, 1 of the base plate 10 are formed.
, And lower orifices 22, 22 having a taper portion of which the diameter is reduced downward, and whose lower ends are open, are formed at positions facing the communication holes 16, 16 ,. . The opening diameter of the lower orifice 22 is relatively large. In addition, a rectangular opening 23 is formed on one side of the lower plate 13 so as to face the other end of the arc-shaped groove 18 formed in the outer peripheral portion of the lower surface of the layer of the rubber 11.

The partition wall 6 has a lower plate 13 and an upper plate 12
Are overlapped with each other and their peripheral portions are welded. Then, the upper orifice 17 of the upper plate 12 and the lower orifice 22 of the lower plate 13 form an orifice for the medium and high frequency regions, and the rectangular opening 15 formed in the base plate 10 of the upper plate 12 and the rubber 11 are formed.
The groove 18 formed in the lower layer and the rectangular opening 23 formed in the lower plate 13 form an orifice 24 for the low frequency region which connects the main fluid chamber 8 and the sub fluid chamber 9 with each other. ing.

A thin disk-shaped space is formed between the upper plate 12 and the lower plate 13 by the recess 19 formed on the lower surface of the layer of the rubber 11. A thin disk-shaped diaphragm 25 is housed in the void. The vibrating plate 25 is smaller than the thickness of the accommodating space, that is, the depth of the recess 19 formed in the layer of the rubber 11. Therefore, the diaphragm 25 can move vertically 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 vibrating plate 25 through the upper orifice 17, and the fluid pressure in the sub fluid chamber 9 acts on the lower surface through the lower orifice 22. ing.

Next, the operation of the engine mount 1 thus configured will be described.

When the engine is running at a moderately high speed, such as during normal running of the vehicle, a small amplitude vibration of a high frequency is 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. Then, the pressure change is transmitted to the space between the upper plate 12 and the lower plate 13 through the upper orifice 17 of the partition wall 6, and the diaphragm 25 provided in the space.
Oscillates up and down according to the pressure change, and the volume change of the main fluid chamber 8 is absorbed. At this time, the diaphragm 25
The fluid flows through the lower orifice 22 in accordance with the vibration of, and the pressure inside the sub-fluid chamber 9 changes. It

In this way, the vibration of the diaphragm 25 allows the deformation of the elastic body 2 with almost no resistance, and the elasticity of the elastic body 2 absorbs the vibration at that time. When the elastic body 2 resonates with engine vibration,
Since the fluid flowing through the upper orifice 17 resonates with its vibration with a predetermined phase difference, the resonance amplitude of the elastic body 2 is suppressed.

Further, when vibration with an extremely large amplitude occurs, such as when the engine is cranking or during a shake during normal traveling, the elastic body 2 is largely deformed, and the volume of the main fluid chamber 8 is significantly changed. In such a case, even if the diaphragm 25 moves up and down, the volume change is not absorbed. Therefore, the fluid flows through the narrow and long low frequency range orifice 24,
Vibration is damped by the flow resistance.

Thus, in order for the fluid flowing through the orifice 17 to resonate at a predetermined frequency, the orifice 17
It is necessary to accurately set the effective sectional shape of and to make its length sufficiently long. Further, in order to allow the deformation of the elastic body 2 without any resistance when vibrating in the medium and high frequency range, the total cross-sectional area of the upper orifice 17 and the lower orifice 22 which constitute the orifice for the medium and high frequency range is sufficient. Therefore, the flow resistance of the fluid flowing through the orifice must be reduced. Therefore, it is necessary to increase the number of the orifices 17 and 22 when making them small in diameter. Further, in order to prevent vortices and the like from occurring in the fluid flowing between the orifices 17 and 22 and the cavity in which the diaphragm 25 is housed, the orifices 17 and 22 are tapered. It is also necessary to do so.

On the other hand, the low-frequency region orifice 24 is required to have a small cross-sectional area and an extremely long length so that the fluid flowing therethrough can be sufficiently attenuated.

In the case of this engine mount 1, since the upper plate 12 in which the upper orifice 17 and the low frequency region orifice 24 are formed is the base plate 10 made of a thin steel plate and the rubber 11 is burned, the orifice 17, The effective cross-sectional shape of 24 can be accurately determined by the openings 14 and 15 formed in the base plate 10. Further, since the shape of the orifices 17 and 24 in the length direction is secured by the rubber 11 which can be easily molded, it is easy to form a complicated shape having a taper or the like. Further, since it is possible to form a thin wall between the upper orifices 17 and 17 or between the orifices 17 and 24, it is possible to increase the number of the medium and high frequency range orifices and increase the total cross-sectional area thereof. .

The rigidity of the partition wall 6 is determined by the base plate 10 made of a steel plate.
And the lower plate 13. Further, since the thickness is secured by the rubber 11, the partition wall 6 having the long orifices 17 and 24 while being lightweight can be obtained.

Further, by forming the upper plate 12 in which the rubber 11 is baked on the base plate 10 made of a steel plate as described above, the stopper 21 made of the rubber 11 can be integrally provided on the outer peripheral portion 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 at the time of large-amplitude vibration, so that excessive deformation of the elastic body 2 is restricted and the fitting 5 is attached to the partition wall. It is possible to prevent the partition wall 6 from being damaged by coming into contact with the partition wall 6. Further, since the rubber 11 seals between the upper plate 12 and the lower plate 13, it is not necessary to use a separate sealing member. A seal member that seals between the upper plate 12 and the housing 3 can also be formed integrally with the upper plate 12 by the rubber 11. Therefore, it is possible to reduce the number of parts.

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

In the partition wall 6 of FIG. 4, the upper plate 12 is
It is said to be similar to the one shown in Figs. The lower plate 13 is, like the upper plate 12, made by vulcanizing and baking the rubber 31 on the base plate 30 made of a thin steel plate.

That is, the base plate 30 is a thin dish having a brim on the peripheral edge, and a large number of circular openings are formed on the bottom surface of the central portion.
34, 34, ... are formed. Further, on one side of the bottom surface thereof, a rectangular opening 35 is formed which is continuous with the other end of the groove 18 formed in the outer peripheral portion of the lower surface of the upper plate 12. Rubber 31
Are filled in the recesses of the base plate 30 to form a rubber layer. A large number of communication holes 36, 36, ... Which are continuous with the openings 34, 34, ... Of the base plate 30 are formed in the layer of the rubber 31. The upper end of the communication hole 36 is opened to the upper surface of the layer of the rubber 31, and the upper end thereof is formed with a taper portion that widens upward. Thus, the lower orifice that vertically penetrates the lower plate 13 by the opening 34 of the base plate 30 and the communication hole 36 of the layer of the rubber 31.
22 are formed.

Other configurations are similar to those shown in FIGS.

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 a sufficient length. The fluid flowing through the orifice 22 can also cause resonance. Therefore,
Resonance of the fluid occurs in the entire medium-high frequency range orifice including the upper orifice 17 and the lower orifice 22, so that the resonance of the elastic body 2 is suppressed more reliably.

Further, in the case of the partition wall 6, the entire circumference of the space where the diaphragm 25 vibrates is formed by the rubbers 11 and 31. Therefore, when the diaphragm 25 vibrates, the diaphragm 25
It will come into contact with 1,31, and the generation of hammering sound is surely prevented.

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 vibration is absorbed only by the orifice.
In such a case, the lower plate 13 can be omitted.

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

(Effects of the Invention) As is apparent from the above description, according to the present invention, a partition wall provided between the main fluid chamber and the sub fluid chamber and having an orifice communicating with each other is formed from a thin metal plate. Since the base plate is made by baking rubber, the thickness of the partition wall is ensured by the rubber, and the partition wall can be made lightweight but thick. Therefore, the orifice formed in the partition wall can be made sufficiently long. Further, since rubber is easily molded, it is easy to form an orifice having a complicated shape. Further, since the work of removing the flash is facilitated and the mounting surface for the support member or the like is not required, the work required after the molding is reduced and the cost is reduced.

Further, since it becomes possible to integrally form the rubber stopper, the seal member and the like, it is possible to reduce the number of parts. When the diaphragm is provided inside the partition wall, the diaphragm can be held by the rubber, so that it is possible to prevent the tapping sound from being generated due to the vibration of the diaphragm.

Therefore, the degree of freedom in design is increased, and the fluid filled type vibration damping device having excellent vibration absorbing characteristics can be obtained.

[Brief description of the drawings]

1 is a vertical sectional view showing an embodiment of a fluid filled type vibration damping device according to the present invention, FIG. 2 is an enlarged vertical sectional view showing a partition wall used in the vibration damping device, FIG. Is a plan view of the partition wall, and FIG. 4 is a vertical sectional view similar to FIG. 2 showing another example of the partition wall. 1 ... Engine mount (fluid-filled type vibration damping device) 2 ... Elastic body 3 ... Housing (supporting member) 5 ... Mounting metal fitting (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 ... Recess (cavity for accommodating diaphragm) 21 ... Stopper 22 ...... Lower orifice 24 …… Low frequency orifice 25 …… Vibration plate

Claims (4)

(57) [Claims] 1. An attachment member to which a fluid is attached, a support member that is arranged apart from the attachment member and attached to a support member, and both ends are fixed to the attachment member and the support member, respectively, and the mainstream is inside. An elastic body that forms a body chamber, a sub-fluid chamber that communicates with the main fluid chamber via an orifice, and has a volume that changes according to the volume change of the main fluid chamber, and these main fluid chambers. A partition wall provided between the sub-fluid chamber and forming the orifice, wherein the main sub-fluid chamber is filled with a fluid; and the partition wall is a thin metal plate. A fluid filled type vibration damping device formed by baking rubber on a base plate made of. 2. The partition wall is provided with cavities communicating with the main fluid chamber and the sub-fluid chamber via orifices, and the fluid pressure in the main-sub fluid chamber acts on both sides in the cavities. The fluid-filled type vibration damping device according to claim 1, further comprising: a vibration plate that vibrates according to a change in fluid pressure. 3. The fluid filled type vibration damping device according to claim 2, wherein the orifice that communicates the void with the main / sub fluid chamber has a tapered portion that widens toward the void. 4. The elasticity of the partition wall is improved by contacting the inner surface of the elastic body located on the outer peripheral portion of the base plate when the elastic body is largely deformed toward the partition wall. The fluid filled type vibration damping device according to claim 1, wherein a stopper for restricting excessive deformation of the body is integrally formed.