JP3040840B2 - Anti-vibration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bush type vibration isolator which is used for a vehicle, particularly an engine mount of an automobile, and absorbs and attenuates vibration from a vibration generating portion.

[0002]

2. Description of the Related Art In an automobile engine, an anti-vibration device as an engine mount is disposed between the engine and a vehicle body.
The vibration of the engine is prevented from being transmitted to the vehicle body. The vibrations generated in the engine include so-called shake vibration generated when the vehicle is traveling at about 70 km / h and so-called idle vibration generated when the vehicle is idling and when the vehicle is traveling at about 5 km / h. . Generally, the shake vibration has a frequency of less than 15 Hz, while the idle vibration has a frequency of 20 to 40 Hz,
The frequency differs between shake vibration and idle vibration.

As a vibration isolator that effectively absorbs vibrations of such a wide frequency range, a liquid-sealed type vibration isolator has been proposed (JP-A-2-42226, JP-A-2-42).
227).

In this vibration isolator, the main liquid chamber and the two sub liquid chambers are arranged in a layer on one side of the inner cylinder, so that the internal structure becomes complicated and the production becomes complicated.

[0005]

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a vibration isolator which does not become complicated even if a plurality of auxiliary liquid chambers are provided.

[0006]

A vibration isolator according to the present invention comprises an outer cylinder connected to one of a vibration generator and a vibration receiver, and an inner cylinder connected to the other of the vibration generator and the vibration receiver. An elastic body provided between the outer cylinder and the inner cylinder and deforming when vibration occurs, a main liquid chamber capable of expanding and contracting the elastic body at least as a part of a partition , and on both sides of the inner cylinder. Before placed
Multiple units separated from the main liquid chamber and connected by a communication passage
And one of the partition walls of the sub liquid chamber provided in the outer cylinder.
A diaphragm constituting a part, the inner cylinder and the plurality of sub- parts.
And a liquid chamber disposed between the inner cylinder and the liquid chamber to restrict radial displacement of the inner cylinder.
Is characterized by having an intermediate member that, a.

[0007]

In the vibration isolator according to the present invention, for example, when the outer cylinder is connected to the vibration receiving section and the inner cylinder is connected to the vibration generating section, the vibration transmitted from the vibration generating section is transmitted through the vibration receiving section via the elastic body. Supported by Vibration is absorbed by the resistance based on the internal friction of the elastic body, and the vibration is absorbed by the passage resistance of the liquid generated in the communication passage between the main liquid chamber and the sub liquid chamber and the liquid column resonance.

Further, in the vibration damping device of the present invention, since the auxiliary liquid chambers are arranged on both sides of the inner cylinder with respect to each other, a conventional vibration isolator in which a plurality of auxiliary liquid chambers are arranged on one side of the inner cylinder. The internal structure is not complicated as compared with the device.

[0009]

【Example】

[First Embodiment] A first embodiment of a vibration isolator 10 according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, the vibration isolator 10 is provided with a mounting frame 12 for mounting on a vehicle body (not shown), and an outer cylinder 16 is inserted into an annular portion 14 of the mounting frame 12. Have been. A thin rubber layer 18 is vulcanized and bonded to the inner peripheral surface of the outer cylinder 16. Further, the outer cylinder 16 is provided with a diaphragm 20 on the upper side in which a part of the thin rubber layer 18 is separated from the inner peripheral surface from the outer cylinder 16.
A diaphragm 21 is provided on the lower side.

An intermediate block 22 formed as a substantially columnar block is inserted into the outer cylinder 16. The intermediate block 22 has a notch 23 formed at an upper middle portion in the axial direction, and a notch 27 formed at a lower middle portion in the axial direction. The outer peripheral surface in the radial direction of the intermediate block 22 is in close contact with the inner peripheral surface of the thin rubber layer 18.

As shown in FIG. 2, a large-diameter hole 29 penetrating in the axial direction and partially communicating with the notch 23 is formed substantially in the center of the intermediate block 22 in the radial direction.

An intermediate cylinder 25 is fitted in the large-diameter hole 29, and an inner cylinder 26 is disposed inside the intermediate cylinder 25 so as to pass therethrough. The inner cylinder 26 is supported by the intermediate cylinder 25 with a main rubber 28 as an elastic body being stretched between the inner cylinder 26 and the intermediate cylinder 25.

In a space surrounded by the main rubber 28 and the large-diameter hole 29, the lower part of the inner cylinder 26 is a main liquid chamber 30, and the upper part of the inner cylinder 26 communicates with the outside. The notch 23
The space surrounded by the outer cylinder 16 is a first sub liquid chamber 32. Note that an air chamber 31 is provided between the diaphragm 20 and the annular portion 14 and communicates with the outside as needed.

On the other hand, a space surrounded by the notch 27 and the outer cylinder 16 is a second auxiliary liquid chamber 34. Further, an air chamber 36 is provided between the diaphragm 22 and the annular portion 14,
It is communicated with the outside if necessary.

In the first embodiment, the diaphragm 20
The surface area of the diaphragm 22 is substantially the same as the surface area of the diaphragm 22, but the thickness of the diaphragm 20 is
Is larger than the thickness. For this reason, the rigidity of the diaphragm 20 with respect to the liquid pressure is set larger than that of the diaphragm 22.

As shown in FIG. 1, a groove 38 is formed on the radially outer peripheral surface of the intermediate block 22 on the side of the arrow A in FIG. 1 along the outer peripheral direction. The upper end of the groove 38 is connected to the notch 23, and the lower end is connected to the main liquid chamber 3 through a hole 40.
0, and is surrounded by the outer cylinder 16 so that the first communication passage 4
2 are formed.

Further, in the intermediate block 22, a second communication passage 44 is formed between the main liquid chamber 30 and the second sub liquid chamber 34, as shown in FIG. The main liquid chamber 30 and the second sub liquid chamber 34 are always in communication with each other.

The main liquid chamber 30, the first sub liquid chamber 32, the second sub liquid chamber 34, the first restriction passage 42 and the second restriction passage 44.
Is filled with a liquid such as water or oil.

In the first embodiment, the size of the second communication passage 44 is made larger than that of the first communication passage 42 (the size of the communication passage is expressed by the following equation. This is a dimensionless parameter: the size of the communication passage = (cross-sectional area perpendicular to the length of the communication passage) ^1/2 / the length of the communication passage.

Next, the operation of this embodiment will be described. When the frame 12 is attached to a vehicle body (not shown) and the inner cylinder 26 is connected to an engine (not shown), the vibration of the engine is
It is supported by a vehicle body (not shown) via the main body rubber 28. At this time, the main rubber 28 is elastically deformed and the vibration is absorbed by the damping action based on the internal friction.

[0022] (for example, shake vibration of a frequency lower than, for example, 15H _Z) when the vibration is relatively low frequency of the engine, the liquid of the main liquid chamber 30 and the second auxiliary liquid through the second communication passage 44 Comes and goes with room 34. At this time, the first sub liquid chamber 3
The second diaphragm 20 hardly deforms,
The volume of the first sub liquid chamber 32 changes little and the liquid is
Does not flow 2. This is the diaphragm 2 in the first sub liquid chamber 32.
0 is higher in rigidity than the diaphragm 22 in the second sub liquid chamber 34. Therefore, shake vibration is absorbed by the passage resistance of the liquid in the second communication passage 44 or the liquid column resonance.

Further, when the vibration of the engine becomes high (for example, in the case of idling operation or when the vehicle speed is 5 km / h)
Idle vibration frequency 20~40H _Z) which occurs when the following second communication passage 44 becomes clogged. Therefore, the liquid in the main liquid chamber 30 passes through the first communication passage 42 and deforms the diaphragm 20, and the main liquid chamber 30 and the first sub liquid chamber 32
Come and go between. Thus, the dynamic spring constant of the vibration isolator 10 is reduced due to the liquid column resonance in the first communication passage 42 for the liquid.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIGS. The same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIGS. 4 and 5, the intermediate block 46 of the second embodiment is different from the intermediate block 22 of the first embodiment.
A pair of grooves 48 are formed on the outer peripheral surface in the radial direction and on the radial side on the opposite side to the arrow A direction along the outer peripheral direction. The upper ends of these grooves 48 are connected to the notch 23, and the lower ends are connected to the notch 27, forming a first communication path 50 surrounded by the outer cylinder 16.

As shown in FIG. 4, a groove 52 is formed in the intermediate block 22 in the vicinity of the end in the direction of arrow B in FIG. As shown in FIGS. 4 and 5,
One end of the groove 52 is connected to the notch 27, and the other end is connected to the main liquid chamber 30 through the hole 54, and is surrounded by the outer cylinder 16 to form a second communication passage 56. . In addition,
The second communication path 56 is longer than the first communication path 42 and has a smaller cross-sectional area perpendicular to the longitudinal direction.

Next, the operation of the second embodiment will be described. When the vibration of the engine is at a relatively low frequency (shake vibration), the liquid in the main liquid chamber 30 moves to and from the second sub liquid chamber 34 via the second communication path 56. At this time, the first sub liquid chamber 32
Of the first sub liquid chamber 32 is small and the liquid is not deformed.
Does not flow. This is the same as the diaphragm 20 in the first sub liquid chamber 32.
This is because the rigidity of the second auxiliary liquid chamber 34 is higher than that of the diaphragm 22. Therefore, the shake vibration is absorbed by the passage resistance of the liquid in the second communication passage 56 or the liquid column resonance.

When the vibration of the engine increases (idle vibration), the second communication passage 56 is clogged. For this reason, the liquid in the main liquid chamber 30 deforms the diaphragm 21 through the first communication path 50, and moves between the main liquid chamber 30 and the first sub liquid chamber 32. Therefore, the first communication path 50 of the liquid
The dynamic spring constant of the vibration isolator 10 is reduced by the liquid column resonance in the inside.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIGS. The same components as those of the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 6, the intermediate block 58 of the third embodiment is different from the intermediate block 22 of the first embodiment, and the first communication path 42 is omitted.

As shown in FIG. 7, a groove 60 is formed on the intermediate block 58 on the side opposite to the direction of arrow A in FIG. The upper end of the groove 60 is the notch 2
3, the lower end is connected to the notch 27,
A first communication path 62 is formed surrounded by the outer cylinder 16. Also, as shown in FIG. 6, an arrow A in FIG.
A groove 6 is formed on the radially outer peripheral surface of the
4 are formed. The upper end of the groove 64 is formed by the notch 23
The lower end is connected to the main liquid chamber 30 via a hole 66, and is surrounded by the outer cylinder 16 to form a second communication passage 68.

The second communication passage 68 has a smaller cross-sectional area perpendicular to the longitudinal direction than the first communication passage 62.

Next, the operation of the third embodiment will be described. When the vibration of the engine is at a relatively low frequency (shake vibration), the liquid in the main liquid chamber 30 flows through the second communication passage 68, the first sub liquid chamber 32, and the first communication passage 62 to the second sub liquid. Comes and goes with room 34. Therefore, the shake vibration is absorbed by the passage resistance or liquid column resonance of the liquid in the second communication passage 68, the first sub liquid chamber 32, and the first communication passage 62. At this time, the diaphragm 20 of the first sub liquid chamber 32 hardly deforms. This is the diaphragm 2 in the first sub liquid chamber 32.
0 is higher in rigidity than the diaphragm 22 in the second sub liquid chamber 34.

When the vibration of the engine increases (idle vibration), the first communication passage 62 is clogged. For this reason, the liquid in the main liquid chamber 30 deforms the diaphragm 20 of the first sub liquid chamber 32 and moves between the main liquid chamber 30 and the first sub liquid chamber 32. Therefore, the first communication path 62 of the liquid
The dynamic spring constant is reduced by the liquid column resonance in the inside.

In the first embodiment, the diaphragm 20
Of the diaphragm 21 is made higher than the rigidity of the diaphragm 21.
Although the size of the communication path 42 is made larger than the size of the second communication path 44, the present invention is not limited to this, and the rigidity of the diaphragm 21 is set to be larger than the rigidity of the diaphragm 20, and the second communication path 44 May be set to be larger than the size of the first communication passage 42 (the factors that determine the rigidity of the diaphragm with respect to the liquid pressure include the surface area, the thickness, the hardness of the material, and the like. Rigidity against pressure can be determined, for example, increasing the surface area of the diaphragm decreases rigidity against hydraulic pressure, decreasing the surface area increases rigidity, and decreasing the diaphragm thickness decreases rigidity against hydraulic pressure. In addition, increasing the thickness of the material increases the rigidity, and increasing the hardness of the material increases the rigidity with respect to the hydraulic pressure, and decreasing the hardness of the material decreases the rigidity with respect to the hydraulic pressure. ). The diaphragm 20 and the diaphragm 2 of the vibration isolator 10 shown in Table 1 below in the first embodiment.
Modifications 1 to 3 in which the rigidity of the first communication passage 1 is changed and the sizes of the first communication passage 42 and the second communication passage 44 are respectively changed are shown.

[0036]

[Table 1] In addition, the first communication passage 42 described in Table 1 above,
The size of the second communication path 44 is a dimensionless parameter represented by the following equation.

The size of the communication path = (cross-sectional area perpendicular to the length of the communication path) ^1/2 / length of the communication path The types of vibration to be absorbed described in Table 1 above are relative. It means high and low, and the magnitude of the frequency is not limited.

In the first and second embodiments, the shake vibration and the idle vibration are absorbed.
The present invention is not limited to this, and the sizes of the first communication passage 42 and the second communication passage 44, the diaphragm 20 and the diaphragm 2
1 may be tuned to absorb the shake vibration (low frequency vibration) and the muffled sound (high frequency vibration), and the idle vibration (low frequency vibration) and the muffled sound (high frequency vibration) may be absorbed. You may make it absorb. In addition,
Here, the muffled sound refers to a vibration having a frequency of about 80 Hz or more, but the frequency is not necessarily limited to about 80 Hz.

[0039]

As described above, the vibration isolator according to the present invention has the following features.
With the above configuration, even if a plurality of sub-liquid chambers are provided, an excellent effect that the structure is not complicated can be obtained.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a vibration isolator according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the vibration isolator according to the first embodiment of the present invention, taken in a direction perpendicular to an axis.

FIG. 3 is a sectional view of the vibration isolator according to the first embodiment of the present invention, taken along line III-III of FIG. 2;

FIG. 4 is an exploded perspective view showing a vibration isolator according to a second embodiment of the present invention.

FIG. 5 is a sectional view of a vibration isolator according to a second embodiment of the present invention, taken in a direction perpendicular to an axis.

FIG. 6 is an exploded perspective view showing a vibration isolator according to a third embodiment of the present invention.

FIG. 7 is a sectional view of the vibration isolator according to the first embodiment of the present invention, taken in a direction perpendicular to an axis.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vibration isolator 16 Outer cylinder 26 Inner cylinder 28 Body rubber (elastic body) 30 Main liquid chamber 32 First sub liquid chamber (Sub liquid chamber) 34 Second sub liquid chamber (Sub liquid chamber)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-11945 (JP, A) JP-A 1-176827 (JP, A) JP-A-62-167949 (JP, A) JP-A-1- 250636 (JP, A) Japanese Utility Model 2-122249 (JP, U) Japanese Utility Model Showa 64-27549 (JP, U) Japanese Utility Model Utility Model 2-53544 (JP, U) Japanese Utility Model Utility Model 1-1121742 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F16F 13/14 B60K 5/12

Claims (1)

(57) [Claims] 1. An outer cylinder connected to one of a vibration generator and a vibration receiver, an inner cylinder connected to the other of the vibration generator and the vibration receiver, and between the outer cylinder and the inner cylinder. An elastic body that is provided and deforms when vibration is generated; a main liquid chamber that can expand and contract with the elastic body as at least a part of a partition; and is disposed on both sides of the inner cylinder and is isolated from the main liquid chamber.
A plurality of sub-liquid chambers and a part of a partition wall of the sub-liquid chamber provided in the outer cylinder.
A diaphragm disposed between the inner cylinder and the plurality of sub liquid chambers;
Vibration damping device, characterized in that it comprises an intermediate member, a for restricting the radial displacement.