JPH1047415A - Vibration control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently absorb vibrations of a wider frequency range by providing the first and the second orifices to interconnect liquid chambers in a vibration control device. SOLUTION: An elastic body 16 is mounted between a top fitting plate 18 and a support cylinder 14 connected to a bottom fitting plate 12. The top fitting plate 18, the bottom fitting plate 12 and the support cylinder 14 define a liquid chamber 26 therebetween. A bulk head material 28 is disposed in the liquid chamber 26 to divide it into two chambers of a pressure-receiving liquid chamber 26A and a sub-liquid chamber 26B. The bulk head material 28 is formed at its outer peripheral end 28A with a groove 30 to thereby form an orifice 40 between the thin portion of the elastic body 16 and the groove 30, and is perforated with an orifice 48 to thereby interconnect the pressure-receiving liquid chamber 26A and the sub-liquid chamber 26B. The orifice 48 is made smaller than the orifice 40 in length and in sectional area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration device applied to a case where transmission of vibration from an engine mounted on a vehicle is prevented, and to a mount for supporting a member generating vibration. Applicable.

[0002]

2. Description of the Related Art For example, a vehicle has a structure in which a vibration isolator as an engine mount is disposed between an engine of a vehicle serving as a vibration generating unit and a vehicle body serving as a vibration receiving unit. The generated vibration is absorbed by the vibration isolator and is prevented from being transmitted to the vehicle body.

[0003] That is, as this vibration isolator, there is known one in which an elastic body and a pair of liquid chambers are provided inside the vibration isolator, and these liquid chambers are communicated with each other by an orifice serving as a restriction passage. When the mounted engine operates and generates vibration, the vibration is absorbed by the vibration damping function of the elastic body and the viscous resistance of the liquid in the orifice communicating with these liquid chambers, and the vibration is transmitted. It is designed to block.

[0004] As one example, a vibration isolator 110 as shown in FIG. 3 is known. The vibration isolator 110 includes a rubber elastic body 112 and a diaphragm 114 as shown in FIG.
A liquid chamber 116 is located between the liquid chambers 116, and a partition member 118 for dividing the liquid chamber 116 into a pair of liquid chambers 116A and 116B is provided in the liquid chamber 116. Further, an orifice 120 is provided in the partition member 118. It is a thing.

[0005] In the vibration isolator 110, not only the vibration is absorbed by the elastic body 112 but also the orifice 120
The liquid in both the liquid chambers 116A and 116B flows through to absorb the vibration, thereby reducing the vibration.

[0006]

However, with a single orifice communicating between a pair of liquid chambers as shown in the figure, the frequency band in which liquid resonance occurs is narrow. Therefore, for example, if the resonance point is set to the shake vibration region, in the idle vibration region, the dynamic spring constant Kd increases, and the vibration cannot be absorbed, and the vibration-proof effect in a wide frequency band cannot be improved. .

The present invention has been made in view of the above circumstances, and has as its object to provide a vibration isolator capable of sufficiently absorbing vibrations of a wide range of frequencies.

[0008]

According to a first aspect of the present invention, there is provided a vibration isolator which is connected to one of a vibration generator and a vibration receiver, and connected to the other of the vibration generator and the vibration receiver. A second mounting member, an elastic body interposed between these mounting members and capable of being elastically deformed, and a pressure receiving member capable of expanding and contracting the elastic body as at least a part of a partition wall and being filled with a liquid. A liquid chamber, a sub liquid chamber that can be expanded and contracted and filled with a liquid, a partition wall member that is disposed between the pressure receiving liquid chamber and the sub liquid chamber to partition therebetween, and the pressure receiving liquid chamber. A first orifice communicating with the sub-liquid chamber, and a hole formed in the partition wall material smaller and shorter than the first orifice and between the pressure-receiving liquid chamber and the sub-liquid chamber; And a second orifice communicating therewith.

According to a second aspect of the present invention, in the vibration isolator of the first aspect, the first orifice is formed in an arc shape along an outer periphery of the partition wall material.

The operation of the vibration isolator according to claim 1 will be described below. An elastic body is interposed between the first mounting member and the second mounting member, and the liquid is filled in a pressure-receiving liquid chamber that can be expanded and contracted by using the elastic body as at least a part of a partition. Further, a partition member is disposed between the pressure-receiving liquid chamber and the expandable / contractible sub-liquid chamber to partition therebetween.

In addition to the first orifice communicating between the pressure-receiving liquid chamber and the sub-liquid chamber, the second orifice having a smaller cross-sectional area than the first orifice is formed by the pressure-receiving liquid chamber and the sub-liquid. A hole is formed in a partition wall material that separates the pressure receiving chamber from the chamber, and communicates between the pressure receiving liquid chamber and the sub liquid chamber.

As described above, when the vibration is transmitted from the vibration generating portion connected to any of the mounting members, the vibration is transmitted to the elastic body through any of the mounting members, and the vibration is generated by the deformation of the elastic body. Vibration is less likely to be transmitted to the vibration receiving portion side that is absorbed and connected to the other mounting member. Further, the pressure receiving liquid chamber expands and contracts with the deformation of the elastic body, and the auxiliary liquid chamber communicated with the pressure receiving liquid chamber via the first orifice and the second orifice expands and contracts accordingly. Changes and flows occur, and the damping effect based on the viscous resistance of the liquid flow and the liquid resonance can improve the vibration isolation effect.

Further, since the second orifice is smaller and shorter in length than the first orifice and is bored in the partition wall material between the pressure-receiving liquid chamber and the sub-liquid chamber, the first orifice has a vibration isolating function. It is possible to improve the vibration damping effect of vibration in a high frequency band at a small amplitude where the effect is insufficient, and it becomes possible to sufficiently absorb vibration in a wide frequency range.

For example, by setting the resonance point of the first orifice in the shake vibration region and setting the resonance point of the second orifice in the idle vibration region, it is possible to improve the anti-vibration effect in both vibration regions. it can.

The operation of the vibration isolator according to claim 2 will be described below. The present invention has the same effect as the first embodiment. However, in the present invention, since the first orifice is formed in an arc shape along the outer periphery of the partition wall material, the first orifice can be formed longer. For this reason, it is possible to increase the difference between the vibration frequency band that can be absorbed by the first orifice and the vibration frequency band that can be absorbed by the second orifice. The anti-vibration effect in the band can be further improved.

[0016]

1 and 2 show an embodiment of a vibration isolator according to the present invention, and the present embodiment will be described with reference to these drawings.

As shown in FIG. 1 showing the present embodiment, the vibration isolator 10 is illustrated on a vehicle body (not shown) in the center of the lower portion of a bottom metal fitting 12 forming the lower side of the vibration isolator 10. A bolt 13 for connecting and fixing by screwing a nut that does not protrude. The periphery of the bottom metal fitting 12 is a cylindrical upright wall 12A, and a support cylinder 14 is disposed at the upper end thereof.

The support cylinder 14 has a disk-shaped flange portion 14A, an outer peripheral end of the flange portion 14A is bent, and an upright wall 12A of the bottom metal fitting 12 is caulked to the flange portion 14A. The support cylinder 14 is the bottom plate fitting 12
It is stuck to. A tubular portion 14B is provided upright at a right angle from the inner peripheral portion of the flange portion 14A of the support cylinder 14, and a support tubular portion 14C that expands in a tapered shape is formed continuously at an upper end portion of the tubular portion 14B. . As described above, the first mounting member is constituted by the bottom plate 12 and the support cylinder 14 which are fixed to each other.

At the center of the upper part of the support cylinder 14C, a top plate 18 as a second mounting member is arranged, and a bolt 19 projects upward from the center of the top plate 18.
The protruding bolt 19 is used for connection to the engine, and the engine is fixed by screwing a nut (not shown).

The outer peripheral surface of a rubber-made elastic body 16 having a cylindrical shape is vulcanized and bonded to the inner peripheral surface of the support cylindrical portion 14C. The upper surface and the inner peripheral surface of the elastic body 16 It is vulcanized and bonded to the metal fitting 18 and the bolt 19. Therefore, the elastic body 16 is interposed and attached between the top metal fitting 18 and the support cylinder 14 fixed to the bottom metal fitting 12. A thin rubber portion 16A extending from the elastic body 16 is also vulcanized and bonded to the outer peripheral surface side of the support cylinder 14.

On the other hand, a rubber diaphragm 22 is caulked and fixed to the flange 14A of the support cylinder 14 together with the upright wall 12A of the bottom plate fitting 12.
2. The space defined by the inner wall surfaces of these members surrounded by the support cylinder 14 and the elastic body 16 constitutes the liquid chamber 26. The liquid chamber 26 is filled and sealed with a liquid such as ethylene glycol.

A partition member 28 made of, for example, a resin material is disposed in the liquid chamber 26.
Are divided into a pressure receiving liquid chamber 26A and a sub liquid chamber 26B. For this reason, as shown in FIG.
A can be expanded and contracted by using the elastic body 16 as at least a part of the partition, and the auxiliary liquid chamber 26B can be expanded and contracted by the diaphragm 22.

The outer peripheral end 2 which is the outer peripheral surface of the partition member 28
8A, a groove 30 is formed over substantially the entire circumference along the outer peripheral end 28A, and an orifice 40 serving as a passage between the thinned portion of the elastic body 16 and the groove 30 is formed in an arc shape.

A small hole 42 is formed at one end of the orifice 40 for communicating the pressure receiving liquid chamber 26A with the inside of the orifice 40. At the other end, the sub liquid chamber 26B and the orifice 40 are formed.
A small hole 44 communicating with the inside is formed. Therefore, the orifice 40 and the small holes 42 and 44 are
And a first orifice that communicates with the auxiliary liquid chamber 26B.

The lower portion of the outer peripheral end 28A protrudes outward, abuts against the bottom surface of the flange 14A of the support cylinder 14, and the flange 1 along with the diaphragm 22.
4A and caulked. Further, an air chamber 46 is provided between the diaphragm 22 and the bottom plate 12 to allow the diaphragm 22 to be deformed.

On the other hand, an orifice 48, which is a second orifice, is formed in the center of the partition wall member 28 in a hole shape. The orifice 48 also allows the pressure receiving liquid chamber 26A and the auxiliary liquid chamber 26B to be formed. Is communicated with. The longitudinal direction of the orifice 48 (the direction in which the liquid passes)
Since the orifice 48 is simply perforated in the partition wall member 28, the length is shorter than the length of the orifice 40 in the longitudinal direction, and the cross section is also smaller in diameter than the orifice 40.

Specifically, the vertical height of the orifice 40 in the cross section shown in FIG.
The width of the partition wall 28 in the horizontal direction is 5.15 mm, and the length along the outer periphery of the partition wall member 28 is 140 mm. On the other hand, the inner diameter of the orifice 48 is 1.5 mm, and the length along the vertical direction is 3.5 mm.

As a result of setting the cross-sectional areas and the lengths of the orifices 40 and 48 in this manner, the orifice 40 can effectively absorb low-frequency band shake vibration and the like, and the orifice 48 becomes high-frequency band It becomes possible to effectively absorb idle vibration and the like.

When assembling the vibration isolator 10 of the present embodiment, the partition member 28 is supported by the support cylinder 14 while the vibration isolator 10 is immersed in a tank (not shown) that stores liquid.
Then, the diaphragm 22 and the bottom plate 12 are overlapped, and they are caulked and fixed. Thereby, the assembly of the entire structure of the vibration isolator 10 in which the liquid is injected into the liquid chamber 26 is completed.

Next, the operation of the present embodiment will be described. When the engine mounted on the top plate 18 operates, vibration of the engine is transmitted to the elastic body 16 via the top plate 18. The elastic body 16 is deformed and acts as a vibration absorber, and can absorb vibration by a vibration damping function based on internal friction of the elastic body 16. The pressure receiving liquid chamber 26A expands and contracts with the deformation of the elastic body 16, and the orifice 40,
Sub liquid chamber 26B communicated with pressure receiving liquid chamber 26A via
Expands and contracts due to the deformation of the diaphragm 22, so that pressure changes and flows occur in the liquids in the orifices 40 and 48, the pressure receiving liquid chamber 26A and the sub liquid chamber 26B.

Therefore, the vibration is absorbed by the deformation of the elastic body 16, the change in pressure of the liquid, the viscous resistance of the liquid flow based on the flow, and the damping action due to the liquid resonance, and the vibration damping effect is improved, and the vibration is improved and the vibration is applied to the vehicle body. Is difficult to be transmitted.

Further, the orifice 48 is connected to the orifice 4
Pressure receiving liquid chamber 26A and auxiliary liquid chamber 2
6B, the vibration is transmitted through the orifice 48 even when the vibration in the high frequency band is transmitted with a small amplitude such that the vibration is not sufficiently reduced only by the orifice 40. Anti-vibration characteristics are maintained,
The vibration isolation effect of the vibration isolation device 10 can be improved, and vibrations of a wide range of frequencies can be sufficiently absorbed.

At this time, since the orifice 40 is formed in an arc shape along the outer periphery of the partition wall member 28, the orifice 40 can be formed longer, and the vibration frequency band that can be absorbed by the orifice 40 and the orifice 48 The difference between the vibration frequency band that can be absorbed can be increased, and the vibration of a wider frequency can be absorbed, and the vibration isolation effect in a wider frequency band can be further improved.

Specifically, the operation is as follows. That is,
With a small amplitude of about 0.1 mm and a frequency of 5 Hz as shown in FIG.
When vibration of about 30 Hz to about 30 Hz is applied to the vibration isolator 10, vibration in a relatively low frequency band is reduced by the orifice 40 and vibration in a high frequency band is reduced by the orifice 48.

For this reason, the characteristic curve A of FIG. 2 is obtained due to the resistance and the liquid column resonance when the liquid flows through the orifices 40 and 48.
The loss coefficient (loss factor) tan δ is represented by the characteristic coefficient B of the vibration isolator 110 according to the prior art.
It becomes wider than anδ, so that vibration in a wider frequency band can be absorbed.

In accordance with this, the characteristic curve C representing the dynamic spring constant Kd of the vibration isolator 10 according to the present embodiment indicates that even if high-frequency vibration that cannot be sufficiently reduced by the orifice 40 occurs, the orifice 40 It can be understood from FIG. 48 that a low dynamic spring is maintained and the vibration isolation characteristics are maintained, and that the effect of the vibration isolation device 10 is sufficiently exhibited.

On the other hand, when the amplitude increases and a large amplitude vibration of about 1.0 mm occurs, the orifice 48 having a small sectional area is clogged, but the vibration is absorbed only by the orifice 40. Become.

In the above embodiment, the orifice 4 is used to absorb shake vibration, idle vibration and the like.
Although 0 and 48 have been described using specific numerical values, they are not limited to these descriptions, and the orifices 40, 4
The dimension 8 may be freely set to a value other than the described value.

Further, in the above embodiment, the bottom plate fitting 12 serving as the first mounting member is connected to the vehicle body serving as the vibration receiving portion, and the top plate fitting 18 serving as the second mounting member is connected to the engine serving as the vibration generating portion. Although the configuration is such that the sides are connected, the configuration may be reversed.

On the other hand, in the above-described embodiment, the purpose of the present invention is to dampen an engine mounted on a vehicle. However, the anti-vibration device of the present invention is used for a body mount of a vehicle or for other uses other than a vehicle. Needless to say, the shape and size of the elastic body and the number of orifices are not limited to those of the embodiment.

[0041]

As described above, the vibration isolator according to the present invention can sufficiently absorb vibrations in a wide frequency range.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a vibration isolator according to the present invention.

FIG. 2 is a diagram showing a graph representing the vibration isolation performance of an embodiment of the vibration isolation device according to the present invention.

FIG. 3 is a cross-sectional view showing a vibration isolator according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vibration isolator 12 Bottom plate fitting (1st mounting member) 14 Support cylinder (1st mounting member) 16 Elastic body 18 Top plate fitting (2nd mounting member) 26A Pressure receiving liquid chamber 26B Secondary liquid chamber 28 Partition material 40 Orifice 48 orifice

Claims (2)

[Claims] A first mounting member connected to one of the vibration generating portion and the vibration receiving portion; a second mounting member connected to the other of the vibration generating portion and the vibration receiving portion; An elastic body interposed therebetween and elastically deformable; a pressure-receiving liquid chamber capable of expanding and contracting the elastic body as at least a part of a partition and being filled with a liquid; A sub-liquid chamber, a partition wall member disposed between the pressure-receiving liquid chamber and the sub-liquid chamber to partition the sub-liquid chamber, and a first member communicating between the pressure-receiving liquid chamber and the sub-liquid chamber. An orifice; and a second orifice, which is smaller and shorter than the first orifice and is formed in the partition wall material in a hole shape and communicates between the pressure receiving liquid chamber and the sub liquid chamber. And anti-vibration device. 2. The vibration isolator according to claim 1, wherein the first orifice is formed in an arc shape along an outer periphery of the partition wall material.