JPH04321834A - Vibration isolating device - Google Patents

Abstract

PURPOSE:To provide a vibration isolating device which is not complicated in structure by providing plural liquid chambers. CONSTITUTION:An intermediate block 26 is disposed inside an outer cylinder 16. An intermediate cylinder 25 is disposed in a large-diameter hole of the intermediate block 22, and an inner cylinder 26 is disposed inside the intermediate cylinder 25. An elastic body 28 is laid between the intermediate cylinder 25 and the inner cylinder 26, and a main liquid chamber 30 surrounded by the elastic body 28 and the large-diameter hole 29 is provided below the inner cylinder 26. The first sub-liquid chamber 32 surrounded by the intermediate block 22 and the outer cylinder 16 is provided above the intermediate block 22, and the second sub-liquid chamber 32 surrounded by the intermediate block 22 and the outer cylinder 16 is provided below the intermediate block 22. The first connecting path 44 for connecting the first sub-liquid chamber 34 to the main liquid chamber 30 is disposed in the outer periphery of the intermediate block 22. The second connecting path 44 for connecting the second sub-liquid chamber 34 to the main liquid chamber 30 is disposed in the lower portion of the intermediate block 22. Thus, plural liquid chambers are disposed on both sides, with the inner cylinder 26 interposed therebetween, so that the internal structure will not be complicated.

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 isolating device used in engine mounts of vehicles, particularly automobiles, for absorbing and damping vibrations from vibration-generating parts.

0002

[Prior Art] A vibration isolating device serving as an engine mount is disposed between the engine and the vehicle body in an automobile engine.
It is designed to prevent engine vibrations from being transmitted to the vehicle body. The vibrations that occur in the engine include the so-called shake vibration that occurs when the vehicle is running at about 70 km/h, and the so-called idling vibration that occurs when the vehicle is idling and when the vehicle is running 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 shake vibration and idle vibration have different frequencies.

[0003] As a vibration isolator that effectively absorbs vibrations with such a wide frequency range, a liquid-filled type anti-vibration device has been proposed (Japanese Unexamined Patent Publication No. 2-42226, Japanese Unexamined Patent Publication No. 2-42).
Publication No. 227).

In this vibration isolator, the main liquid chamber and two sub-liquid chambers are arranged in layers on one side of the inner cylinder, which makes the internal structure complicated and complicated to manufacture.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned facts, it is an object of the present invention to provide a vibration isolator whose structure does not become complicated even when a plurality of sub-liquid chambers are provided.

[0006]

[Means for Solving the Problems] The present invention provides an outer cylinder connected to one of a vibration generating part and a vibration receiving part, an inner cylinder connected to the other of the vibration generating part and a vibration receiving part, and an outer cylinder connected to the other of the vibration generating part and the vibration receiving part. and an elastic body that is provided between the inner cylinder and the inner cylinder and deforms when vibration occurs;
In the vibration isolator, the vibration isolating device includes a main liquid chamber that is expandable and contractible, with the elastic body being at least part of a partition wall, and a plurality of sub-liquid chambers isolated from the main liquid chamber, wherein the plurality of sub-liquid chambers are connected to an inner cylinder. It is characterized by being placed on both sides.

[0007]

[Operation] In the vibration isolating device of the present invention, for example, when the outer cylinder is connected to the vibration receiving part and the inner cylinder is connected to the vibration generating part, the vibration transmitted from the vibration generating part is transmitted to the vibration receiving part through the elastic body. is supported. Vibration is absorbed by resistance based on internal friction of the elastic body, and also by liquid passage resistance and liquid column resonance generated in the communication path between the main liquid chamber and the sub liquid chamber.

Furthermore, in the vibration isolator of the present invention, since the sub-liquid chambers are arranged on both sides of the inner cylinder, it is different from the conventional vibration isolator in which a plurality of sub-liquid chambers are arranged on one side of the inner cylinder. The internal structure is less complicated than that of 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. 1 to 3.

As shown in FIG. 1, this vibration isolator 10 is equipped 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 this mounting frame 12. has been done. A thin rubber layer 18 is vulcanized and bonded to the inner peripheral surface of the outer cylinder 16. Further, this 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 of the outer cylinder 16,
A diaphragm 21 is provided on the lower side.

[0011] An intermediate block 22, which is a substantially cylindrical block, is inserted inside the outer cylinder 16. This intermediate block 22 has a notch 23 formed at its upper axially intermediate portion, and a notch 27 formed at its lower axially intermediate portion. Note that the radially outer circumferential surface of the intermediate block 22 is in close contact with the inner circumferential surface of the thin rubber layer 18.

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

[0013] An intermediate cylinder 25 is fitted into the large diameter hole 29, and an inner cylinder 26 is disposed penetrating inside the intermediate cylinder 25. The inner cylinder 26 is supported by the intermediate cylinder 25 with a main body rubber 28 as an elastic body being stretched between the inner cylinder 26 and the intermediate cylinder 25.

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

On the other hand, a space surrounded by the notch 27 and the outer cylinder 16 is defined as a second sub-liquid chamber 34. Further, an air chamber 36 is formed between the diaphragm 22 and the annular portion 14,
It communicates with the outside as necessary.

Note that in the first embodiment, the diaphragm 20
The surface area of the diaphragm 22 is approximately the same as that of the diaphragm 22, but the thickness of the diaphragm 20 is greater than that of the diaphragm 22.
The thickness is greater than that. Therefore, the rigidity of the diaphragm 20 against hydraulic pressure is made greater than that of the diaphragm 22.

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

Furthermore, as shown in FIG. 2, a second communication passage 44 is formed in the intermediate block 22 between the main liquid chamber 30 and the second sub-liquid chamber 34. The main liquid chamber 30 and the second sub-liquid chamber 34 are always in communication via the main liquid chamber 30 and the second sub-liquid chamber 34 .

These main liquid chamber 30, first sub-liquid chamber 32, second sub-liquid chamber 34, first restriction passage 42 and second restriction passage 44
is filled with liquid such as water or oil.

In the first embodiment, the size of the second communication path 44 is larger than the first communication path 42 (the size of the communication path referred to here is expressed by the following formula). It is a dimensionless parameter.Size of communicating path = (cross-sectional area perpendicular to the length of communicating path) 1/2 / length of communicating path).

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

When the vibration of the engine is relatively low frequency (for example, shake vibration with a frequency of less than 15 Hz), the liquid in the main liquid chamber 30 flows through the second communication passage 44 to the second auxiliary liquid chamber. Go back and forth with 34. At this time, the first sub-liquid chamber 3
The diaphragm 20 of No. 2 hardly deforms,
There is little change in the volume of the first sub-liquid chamber 32 and the liquid flows through the first communication path 4.
2 does not flow. This is the diaphragm 2 of the first sub-liquid chamber 32.
0 has higher rigidity than the diaphragm 22 of the second sub-liquid chamber 34. Therefore, the shake vibration is absorbed by the passage resistance of the liquid in the second communication path 44 or by the liquid column resonance.

[0023] Also, when the vibration of the engine increases (for example, when driving idling or when the vehicle speed is 5 km/h)
Idle vibration with a frequency of 20 to 40 Hz that occurs in the following cases), the second communication passage 44 becomes clogged. Therefore, the liquid in the main liquid chamber 30 passes through the first communication path 42 , deforms the diaphragm 20 , and moves back and forth between the main liquid chamber 30 and the first sub-liquid chamber 32 . As a result, the first liquid communication path 4
The dynamic spring constant of the vibration isolator 10 is reduced by the liquid column resonance within the vibration damper 2 .

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. Note that the same components as those in the first embodiment are given the same reference numerals, and the explanation 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 along the outer circumferential direction on the radial outer circumferential surface on the direction side and on the side opposite to the direction of arrow A. The upper ends of these grooves 48 are connected to the notch 23 and the lower ends are connected to the notch 27, and are surrounded by the outer cylinder 16 to form a first communicating path 50.

As shown in FIG. 4, a groove 52 is formed in the intermediate block 22 along the outer circumferential direction near the side 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 via the hole 54.
6 to form a second communication path 56. Note that the second communication path 56 is longer than the first communication path 42;
The cross-sectional area perpendicular to the length is reduced.

Next, the operation of the second embodiment will be explained. If the engine vibration is relatively low frequency (shake vibration)
, the liquid in the main liquid chamber 30 flows back and forth to the second sub-liquid chamber 34 via the second communication path 56. At this time, the diaphragm 20 of the first sub-liquid chamber 32 hardly deforms, and the volume of the first sub-liquid chamber 32 changes little, and the liquid does not flow through the first communication path 50. This is because the diaphragm 20 of the first sub-liquid chamber 32 has higher rigidity than the diaphragm 22 of the second sub-liquid chamber 34. Therefore, the shake vibration is absorbed by the passage resistance of the liquid in the second communication path 56 or by the liquid column resonance.

Furthermore, when the vibration of the engine increases (idle vibration), the second communicating passage 56 becomes clogged. Therefore, the liquid in the main liquid chamber 30 passes through the first communication path 50, deforms the diaphragm 21, and flows back and forth between the main liquid chamber 30 and the first sub-liquid chamber 32. Therefore, the first liquid communication path 50
The dynamic spring constant of the vibration isolator 10 is reduced due to the liquid column resonance within.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIGS. 6 and 7. Note that the same components as those in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted.

As shown in FIG. 6, the intermediate block 58 of the third embodiment differs from the intermediate block 22 of the first embodiment in that the first communication passage 42 is removed.

As shown in FIG. 7, a groove 60 is formed along the outer circumferential direction of the intermediate block 58 on the side opposite to the direction of arrow A in FIG. The upper end of this groove 60 is the notch 2
3, the lower end is connected to the notch 27,
A first communication passage 62 is formed surrounded by the outer cylinder 16 . Further, as shown in FIG. 6, the arrow A in FIG. 6 of the intermediate block 58
A groove 6 is provided along the outer circumferential direction on the radial outer circumferential surface of the direction side.
4 is formed. The upper end of this groove 64 is the notch 23
The lower end portion is connected to the main liquid chamber 30 through a hole 66, and is surrounded by the outer cylinder 16 to form a second communication passage 68.

The second communicating path 68 has a smaller cross-sectional area perpendicular to its longitudinal direction than the first communicating path 62.

Next, the operation of the third embodiment will be explained. If the engine vibration is relatively low frequency (shake vibration)
, the liquid in the main liquid chamber 30 is transferred to the second communication passage 68 and the first sub-liquid chamber 3.
2. Goes back and forth to the second sub-liquid chamber 34 via the first communication path 62. Therefore, the second liquid communication path 68 and the first sub-liquid chamber 3
2. Shake vibration is absorbed by passage resistance or liquid column resonance within the first communication path 62. Note that at this time, the diaphragm 20 of the first sub-liquid chamber 32 is hardly deformed. This is because the diaphragm 20 of the first sub-liquid chamber 32 has higher rigidity than the diaphragm 22 of the second sub-liquid chamber 34.

Furthermore, when the vibration of the engine increases (idle vibration), the first communication passage 62 becomes clogged. Therefore, the liquid in the main liquid chamber 30 deforms the diaphragm 20 of the first sub-liquid chamber 32 and moves back and forth between the main liquid chamber 30 and the first sub-liquid chamber 32. Therefore, the first liquid communication path 62
The dynamic spring constant is reduced by the liquid column resonance within.

Note that in the first embodiment, the diaphragm 20
The rigidity of the diaphragm 21 is made higher than that of the diaphragm 21, and the first
Although the size of the communication passage 42 is made larger than the size of the second communication passage 44, the present invention is not limited to this, and the rigidity of the diaphragm 21 is set larger than the rigidity of the diaphragm 20, The size of the diaphragm may be set larger than the size of the first communication passage 42 (factors that determine the rigidity of the diaphragm against hydraulic pressure include surface area, thickness, hardness of the material, etc., and the desired liquid can be obtained by combining these factors. You can determine the rigidity against pressure.For example, increasing the surface area of the diaphragm will lower the rigidity against hydraulic pressure, and decreasing the surface area will increase the rigidity.Also, making the diaphragm thinner will lower the rigidity against hydraulic pressure. (The thicker the material, the higher the rigidity. Also, increasing the hardness of the material will increase the rigidity against hydraulic pressure, and decreasing the hardness of the material will decrease the rigidity against hydraulic pressure.) The diaphragm 20 and the diaphragm 2 of the vibration isolator 10 shown in the first embodiment are shown in Table 1 below.
Modifications 1 to 3 are shown in which the rigidity of the first communication path 42 and the second communication path 44 are changed respectively.

[0036]

[Table 1] Note that the first communication path 42 described in Table 1 above,
The size of the second communicating path 44 is a dimensionless parameter expressed by the following equation.

[0037] Size of communication path = (cross-sectional area perpendicular to the length of the communication path)
1/2 / Length of communication path Also, the types of vibrations to be absorbed listed in Table 1 above refer to relative heights, and the magnitude of the frequency is not limited. .

Furthermore, in the first and second embodiments, shake vibrations and idle vibrations are absorbed;
The present invention is not limited to this, and the size of the first communicating path 42 and the second communicating path 44, and the diaphragm 20 and the diaphragm 2
The rigidity of 1 may be tuned to absorb shake vibration (low frequency vibration) and muffled sound (high frequency vibration), and idle vibration (low frequency vibration) and muffled sound (high frequency vibration) may be absorbed. It may also be absorbed. In addition,
The muffled sound here refers to vibrations with a frequency of about 80 Hz or more, but the frequency is not necessarily limited to about 80 Hz.

[0039]

[Effects of the Invention] As explained above, the vibration isolating device of the present invention has
The above structure has an excellent effect that the structure does not become complicated even when a plurality of sub-liquid chambers are provided.

[Brief explanation of drawings]

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

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

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

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

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

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

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

[Explanation of symbols]

10 Vibration isolation device 16 Outer cylinder 26 Inner cylinder 28　　　　　Body rubber (elastic body) 30 Main liquid chamber

Claims (1)

[Claims] 1. An outer cylinder connected to one of the vibration generating part and the vibration receiving part, an inner cylinder connected to the other of the vibration generating part and the vibration receiving part, and a space between the outer cylinder and the inner cylinder. A vibration isolating device comprising: an elastic body that is provided and deforms when vibration occurs; a main liquid chamber that uses the elastic body as at least a part of a partition wall and can be expanded and contracted; and a plurality of auxiliary liquid chambers that are isolated from the main liquid chamber. The vibration isolator according to the invention, wherein the plurality of sub-liquid chambers are arranged on both sides of the inner cylinder.