JPH0226337A - Inner-outer cylinder type fluid sealed vibration isolator - Google Patents

Abstract

PURPOSE:To make improvements in vibration transmissibility so sharply as well as to perform a displacement regulation between an exciting body and an excited body by installing a fluid chamber in an interval between a compression deforming part and a shear deforming part of a supporting elastic body, and adding it with a function as a fluid sealed type vibration isolator. CONSTITUTION:Capacity in a main fluid chamber 24 is varied according to the deformation of a supporting elastic body 16 due to vibration input. A fluid in this chamber 24 is moved in an interval between respective sub-fluid chambers 26 and 28. At this time, each liquid column resonance of orifice passages 40, 42 being interconnected to these sub-fluid chambers 26, 28 is subjected to tuning in advance in response to frequency of a vibration mainly requiring a displacement regulation, whereby relative displacement between an exciting body and an excited body is effectively regulated. In addition, the liquid column resonance in the orifice passages 40, 42 being interconnected to the sub-fluid chambers 26, 28 is subjected to tuning in response to frequency of a vibration mainly requiring vibration absorption, whereby any vibration transmitted between the exciting body and the excited body at the time of inputting this vibration is effectively absorbed.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a vibration isolator of a type in which a supporting elastic body is interposed between an inner cylinder and an outer cylinder, and in particular, the supporting elastic body is An inner and outer cylindrical type fluid-filled vibration damping device composed of a compression deformation part and a shear deformation part separated in the circumferential direction, and a fluid chamber is configured in the space between the compression deformation part and the shear deformation part. Regarding the body.

(Prior art) Generally, a power unit (engine,
(transmission, etc.) is supported by the vehicle body through a vibration isolator called an engine mount, and the vibration isolator reduces the vibration transmission force between the power unit and the vehicle body. ing.

The above-mentioned vibration isolator is provided with a support elastic body such as rubber, and the vibration transmission force is reduced by the vibration absorption function of the support elastic body, but in recent years, incompressible fluid is sealed in the support elastic body. There is a so-called fluid-filled vibration isolator that can effectively reduce the vibration transmission force in a specific frequency range due to the resonance effect of the fluid.

On the other hand, as for the vibration isolator, when the supporting elastic body is cut for some reason, the respective attachments for holding the supporting elastic body prevent the members from being separated from each other, and Conventionally, there are inner and outer cylindrical vibration isolators that can reduce the overall size.

That is, such an inner and outer cylinder type vibration isolator is disclosed in Japanese Patent Application Laid-Open No. 59-65632.
As disclosed in the publication, when a support elastic body is interposed between the inner cylinder and the outer cylinder and this is used as an engine mount, one of the inner cylinder and the outer cylinder is on the vehicle body side, and the other side is on the power unit side. can be attached to.

By the way, the support elastic body of the vibration isolator disclosed in the above-mentioned publication is composed of a compression deformation part that is mainly compressively deformed when the static load of the power unit is applied, and a shear deformation part that is mainly shear deformed. This makes it easy to tune the spring constant to effectively absorb input vibrations.

(Problem to be Solved by the Invention) However, when using such a conventional inner and outer cylindrical vibration isolator as an engine mount, engine shake occurs in the low frequency range between the vehicle body and the power unit. Two typical vibration peaks of idle vibration are generated, and it is necessary to effectively reduce these two vibrations.

However, of the two vibrations mentioned above, engine shake, which exists in a relatively low frequency range, has a large amplitude, and it is necessary to mainly control the displacement of the power unit.On the other hand, idle vibration, which exists in a relatively high frequency range, has a large amplitude. It is necessary to mainly absorb the transmission of vibrations to the vehicle body, and it is extremely difficult to satisfy these two conflicting elements only with a supporting elastic body that has been tuned in advance to have a constant spring constant. There was a problem in that a sufficient displacement regulation effect or a sufficient vibration absorption effect could not be obtained.

Therefore, in view of the conventional situation, the present invention takes advantage of the characteristics of the compression deformation part and the shear deformation part of the supporting elastic body of the inner and outer cylindrical vibration isolators, and creates a fluid chamber between the compression deformation part and the shear deformation part. By adding the function of a fluid-filled vibration isolator, the internal and external cylindrical fluid-filled type can satisfy both the conflicting elements of displacement regulation effect and vibration absorption effect without requiring major changes to the structure. The purpose is to provide a vibration isolator.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes an inner cylinder attached to either the vibrating body or the vibrated body, surrounding the inner cylinder with appropriate intervals, and connecting the vibrating body to the vibrating body. or an outer cylinder attached to the other side of the vibrating body, at least one compression deformation part interposed between the inner and outer cylinders, which is mainly compressively deformed in response to a static load, and at least two parts which are mainly shear deformed. and a support elastic body separated in the circumferential direction from two shear deformation parts, and a space defined by the compression deformation part and shear deformation part of the support elastic body is closed on both sides in the direction of the center axis of the inner cylinder with an elastic thin film. and a liquid is sealed in each of the closed spaces, so that at least one closed space existing in the direction of vibration input between the inner and outer cylinders is used as a main fluid chamber, and the remaining closed spaces are used as auxiliary fluid chambers. ,
The main fluid chamber and the auxiliary fluid chamber are configured to communicate with each other via orifice passages provided along the circumferential direction of the outer cylinder.

(Function) With the above-described structure, in the inner/outer cylinder type fluid-filled vibration isolator of the present invention, the internal volume of the main body chamber changes as the supporting elastic body deforms due to vibration input, and the liquid in the main body chamber changes. It is moved to and from each sub-fluid chamber via an orifice passage.

At this time, by tuning the liquid column resonance in the orifice passage communicating with at least one sub-fluid chamber in accordance with the frequency of the vibration that mainly requires displacement regulation, the vibration is applied when the vibration is input. It can effectively regulate the relative displacement between the vibrating body and the vibrated body, and mainly requires vibration absorption of liquid column resonance in the orifice passage that communicates with the remaining sub-fluid chamber. By tuning in accordance with the vibration frequency, the vibration transmitted between the vibrating body and the vibrated body can be effectively absorbed when the vibration is input.

In addition, in the present invention, the main and auxiliary fluid chambers are configured by individually closing both sides of the space between the compression deformation section and the shear deformation section in the axial direction with elastic thin films. Since the spring constant of the elastic thin film defining the fluid chamber can be easily tuned independently, the liquid column resonance point of the orifice passage can be easily tuned in accordance with the vibration frequency to be damped.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

That is, FIGS. 1 to 7 show an inner and outer cylindrical type fluid-filled vibration isolator showing an embodiment of the present invention. state

The engine mount 10 is provided between a vehicle body and a power unit (not shown), and includes an inner cylinder 12 that is attached to one of the vehicle body or the power unit, and an outer cylinder 14 that is attached to the other of the vehicle body or the power unit. .

A supporting elastic body 16 made of rubber is vulcanized and bonded between the inner cylinder 12 and the outer cylinder 14, and the supporting elastic body I
6 supports the load of the power unit with a buffering function. The support elastic body 16 also includes a compression deformation portion 16a that extends downward in the figure from the inner cylinder 12 and is mainly compressively deformed in response to the static load of the power unit, and a first
It is composed of shear deformation parts 16b and 16C that extend in the left-right direction in the figure and are mainly shear deformed in response to the static load, and these compressive deformation parts 16a and shear deformation parts 16b and 16C are separated in the circumferential direction and are approximately It forms a T-shape. Therefore, the inside of the outer cylinder 14 is formed by the compression deformation part 16a and the shear deformation parts 16b and 16c, which are separated from each other.
,S, are formed.

Here, in this embodiment, the space portion S l+S,
FIG. 2 shows both sides of the inner cylinder 12 of S3 in the central axis direction.

As shown in FIGS. 3 and 4, the elastic thin film 18.
20 and 22, and by sealing a liquid in each of the closed spaces, the space SI is closed.
The chamber corresponding to the space S is defined as the main fluid chamber 24, the chamber corresponding to the space S is defined as the first sub-fluid chamber 26, and the space S is defined as the first sub-fluid chamber 26.
The chamber corresponding to , is defined as the second sub-fluid chamber 28. The main fluid chamber 24 is located in the space S1 located in the acting direction of the displacement force or vibration input to the engine mount 10.
By providing the main fluid chamber 24 for these inputs,
This can most effectively cause a change in the volume within.

Further, the outer cylinder 14 is recessed in the inner radial direction at the center in the central axis direction to form an annular groove 30, into which an orifice structure 32 divided into two in the vertical direction is fitted. .

Note that the outer cylinder 14 is connected to the main fluid chamber 24. The portions corresponding to the first and second sub-fluid chambers 26.28 are cut out, and the outer peripheral portions of each of these fluid chambers 24.26.28 are directly closed by the orifice structure 32.

As shown in FIG. 5, the orifice structure 32 has two openings 34a and 34b communicating with the main fluid chamber 24.
At the same time, as shown in FIG. 6, an opening 36a communicating with the first sub-fluid chamber 26 and an opening 36b communicating with the second sub-fluid chamber 28 are formed. The opening 34a and the opening 36a are connected via a first groove 32a that extends 174 times around the orifice structure 32, and the opening 34b and the opening 36b are , are connected via a second groove 32b extending approximately 1/4 of the way around the orifice structure 32.

As shown in FIG. 7, the orifice structure 32 is fitted into an annular bracket 38 together with the outer cylinder 14,
The bracket 38 allows the first and second grooves 32a, 3
A closed cross section is formed by closing the open portion in the external direction of 2b, and the first groove 32a is connected to the first orifice passage 40.
．． The second groove 32b is configured as the second orifice passage 42.

Therefore, the main fluid chamber 24 and the first sub-fluid chamber 26 are
are communicated with each other via the orifice passage 40, and
The main fluid chamber 24 and the second auxiliary fluid chamber 28 communicate with each other via a second orifice passage 42 .

With the above configuration, in the engine mount 10 of this embodiment, when a relative displacement force or vibration is generated between the vehicle body and the power unit in the direction in which the static load is applied to the power unit, the inner cylinder 12 and the outer cylinder 14 are relatively displaced, and the compression deformation portion 16a of the support elastic body 16 is compressed and tensile deformed, and the shear deformation portion 16b is shear deformed, and the main fluid chamber 24
The internal volume is changed.

Then, the liquid in the main fluid chamber 24 is transferred between the first sub-fluid chamber 26 and the second sub-fluid chamber 28 via the first orifice passage 40 and the second orifice passage 42 .

At this time, the liquid in the first orifice passage 40 is vibrated using the movable liquid as a mass and the expansion elasticity of the main fluid chamber 24 and the first sub-fluid chamber 26 as a spring, and the liquid in the second orifice passage 42 is vibrated. Similarly, the movable liquid is used as a mass and the expansion elasticity of the main fluid chamber 24 and the second sub-fluid chamber 28 is used as a spring to vibrate.

Therefore, the liquids in the first orifice passage 40 and the second orifice passage 42 experience a resonance phenomenon depending on the frequency of the input vibration, and this resonance phenomenon causes the dynamic spring constant of the engine mount 10 to be changed. can be significantly reduced. Furthermore, it has been confirmed through experiments that a peak point with a large loss factor occurs in a frequency range slightly higher than this resonant frequency.

By the way, in this embodiment, the liquid resonance frequency in the first orifice passage 40 is tuned to be slightly lower than the frequency at which engine shake occurs, and is set so that the loss factor is maximized in the engine shake frequency region. In addition, the resonance frequency of the liquid in the second orifice passage 42 is tuned to the frequency region of idle vibration, and the dynamic spring constant is set to be the lowest during the idle vibration.

In this embodiment, the main fluid chamber 24 and the first and second
Elastic membrane 18.20.2 defining secondary fluid chamber 26.28
2 are provided individually, so that the spring constants for determining the expansion elasticity of each can be set independently.

For example, the spring constant of each elastic membrane is 18.20
．． It can be easily tuned by changing the thickness of 22.

In this case, the elastic thin film 18 of the main fluid chamber 24 is made thickest to generate a sufficient pressure change within the main fluid chamber 24 when vibration is input. 2nd orifice passage 40.42
The elastic thin membrane 20.22 of each sub-fluid chamber 26.28 is made thinner than that of the main fluid chamber 24, so that even in this thinner state, the first sub-fluid chamber The elastic thin film 20 of 26 is formed to be thinner than the second auxiliary fluid chamber 28, and tuned so that the resonance frequency is easily set lower in response to engine shake.

Further, in this embodiment, the first orifice passage 40 tuned to engine shake is formed longer than the second orifice passage 42 tuned to idle vibration, so that the liquid in the first orifice passage 40 is The column resonance can be easily set to a lower frequency than the liquid column resonance in the second orifice passage 42, and together with the thickness change of the elastic thin film 20°22, engine shake and idle vibration are reduced. It is possible to reliably set the reduction area.

Note that the length of the first orifice passage 40 is desirably set to be 4 to 16 times the length of the second orifice passage 42.

By the way, the engine mount 10 of this embodiment has a compression deformation portion 16a and shear deformation portions 16b, 16 on the support elastic body 16.
G is provided, so in addition to functioning as a fluid-filled vibration isolator, these compression deformation portions 16a and shear deformation portions 16b
, 16c is also equipped with the functions when installed separately.
It becomes easier to tune the rigidity balance of the engine mount 10 in the vertical direction, longitudinal direction, and horizontal direction.

Note that the engine mount 10 of this embodiment has a support elastic body 16.
has one compressive deformation section 16a and two shear deformation sections 16b,
16C, each of these modified portions 16a, 16b.

The number of 16C may be set according to the number of fluid chambers required, and it is sufficient to provide at least one compressive deformation section and two shear deformation sections.

(Effects of the Invention) As explained above, in the inner/outer cylinder type fluid-filled vibration isolator of the present invention, the support elastic body interposed between the inner and outer cylinders is defined by the compressive deformation part and the shear deformation part. Both sides of the space are closed with elastic thin films, and a liquid is sealed in the closed space to form at least one main fluid chamber and at least two sub-fluid chambers, and the main fluid chamber and each sub-fluid chamber are Since the fluid chambers are communicated with each other through orifice passages provided along the circumferential direction of the outer cylinder, the compressive deformation part and the shear deformation part are provided separately, and the function achieved by separating them is achieved, while the fluid-filled vibration isolation Because it can function as a body, the synergistic effect of both can significantly increase the vibration transmission rate, and also ensures displacement regulation between the vibrating body and the vibrated body. be able to.

In addition, since the main and sub-fluid chambers are each defined by an elastic thin film, the expansion elasticity of the elastic thin film can be easily adjusted individually, so that the liquid column resonance in each orifice passage can be adjusted to a desired frequency. This has the excellent effect of making tuning significantly easier.

[Brief explanation of the drawing]

FIG. 1 is a sectional front view showing one embodiment of the present invention, FIG. 2 is a sectional view taken along the line ■-■ in FIG.
-I[1 line sectional view, Figure 4 is a sectional view taken along the ■-IV line in Figure 1, Figure 5 is a plan view showing an embodiment of the present invention, and Figure 6 is a plan view showing an embodiment of the present invention. The bottom view shown in FIG. 7 is a perspective view showing the assembled state of the present invention. DESCRIPTION OF SYMBOLS 10... Engine mount (internal and external cylinder type fluid-filled vibration isolator), 12... Inner cylinder, 14... Outer cylinder, 16... Support elastic body, 16a... Compression deformation part, 16b, 16C・
... Shear deformation part, 18.20.22 ... Elastic thin film, 2
4...Main fluid chamber, 26.28...Subfluid chamber, 40.
42... Orifice passage. Figure Figure Figure Figure

Claims (1)

[Claims] (1) An inner cylinder attached to one of the vibrating body or the vibrated body; an outer cylinder surrounding the inner cylinder at an appropriate interval and attached to the other of the vibrating body or the vibrated body; a support elastic body which is interposed between the outer cylinders and is separated in the circumferential direction from at least one compression deformation part that is mainly compressively deformed in response to a static load and at least two shear deformation parts that are mainly shear deformed; The space defined by the compressive deformation part and the shear deformation part of the support elastic body is closed on both sides in the direction of the inner cylinder's central axis with an elastic thin film, and a liquid is sealed in each closed space to form an inner and outer part. At least one closed space existing in the vibration input direction between the cylinders is used as a main fluid chamber, and the remaining closed spaces are used as auxiliary fluid chambers,
An inner/outer cylinder type fluid-filled vibration isolator characterized in that the main fluid chamber and the auxiliary fluid chamber are communicated with each other via an orifice passage provided along the circumferential direction of the outer cylinder.