JPH0914333A - Vibration control device - Google Patents

Abstract

PURPOSE: To effectively absorb vibration in a wide range with a simple and inexpective structure. CONSTITUTION: A cutaway recess 20 is disposed in an elastic body 18 opposite to a liquid room 26 such that a part of the elastic body 18 facing the liquid room 26 becomes a thin wall 22 and the cutaway recess 20 is recessed such that it is opened outward in a direction perpendicular to an axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolator applied to prevent transmission of vibrations from a vibration generator, for example, an engine mount for preventing transmission of engine vibrations to a vehicle body, and others. It is applicable to vehicles and general industrial machines.

[0002]

2. Description of the Related Art For example, a vibration isolator as an engine mount is arranged between an engine which is a vibration generating part of a vehicle and a vehicle body which is a vibration receiving part. Is absorbed and is prevented from being transmitted to the vehicle body side. That is, as an example of such a vibration isolation device, a vibration isolation device 110 as shown in FIG. 4 is known, and a conventional technique will be described based on this drawing.

The vibration isolator 110 includes a center member 112 mounted on a bracket on the engine side and an outer cylinder 11.
4, an elastic body 116 made of rubber is provided, a liquid chamber 118 in which a liquid is sealed is provided inside the outer cylinder 114 and the elastic body 116, and the liquid chamber 118 is sealed by a diaphragm 120 made of a rubber film. It is configured by The inside of the liquid chamber 118 is partitioned into a pair of liquid chambers 118A and 118B by a partition member 122, and the limiting passage 124
These liquid chambers 118A and 118B are communicated with each other. The partition member 122 and the diaphragm 1
20 is attached by being sandwiched by both when fixing the lid member 126 to the opening portion of the outer cylinder 114. The lid member 126 is attached to the vehicle body side by a bolt 126A, and therefore, the outer cylinder 114 integral with the lid member 126.
Is attached to the vehicle body side via the lid member 126. When the mounted engine operates to generate vibration, the vibration damping function of the elastic body 116 and the liquid chamber 11
A liquid column resonance of the liquid in the restriction passage 124 that communicates 8A and 118B, etc., is used to generate a damping force, absorb the vibration, and prevent the vibration from being transmitted.

[0004]

However, in the vibration isolator 110 as described above, vibrations in the low frequency range are restricted to the restricted passage 12.
When the liquid in the liquid chamber 4 is attenuated by the flow of the liquid, when the vibration in the higher frequency range is transmitted, the internal pressure of the liquid chamber 118A is increased due to the clogging of the restriction passage 124, and the spring coefficient is increased. As a result, there is a drawback that the vibration cannot be reduced sufficiently.

Further, in order to solve this drawback, a movable piece 128 capable of reciprocating in the partition member 122 as shown in FIG.
It has been proposed that the one having a membrane made of a rubber film instead of the movable piece 128 is provided.
These products have the disadvantages that the structure is complicated, the manufacturing is complicated, the number of parts is large, and the cost is increased.

Further, as shown in FIGS. 6 and 7, a structure is also proposed in which a recess 130 is provided in the elastic member 116 to form a thin portion 132 so as to prevent the internal pressure of the liquid chamber 118A from rising. However, in the case of FIG. 5, since the recess 130 is formed on the side of the liquid chamber, the amount of the liquid sealed in the liquid chamber increases, which causes a problem that the weight of the device increases, and therefore, in FIG. In the case of the product, since the recess 130 is axially recessed by releasing the molding die upward in the drawing, foreign matter is likely to accumulate in the recess 130 and is difficult to be discharged once foreign matter enters. Further, for example, when a center member having a different outer diameter such as a step is used, the recess 130 cannot be formed closer to the center than the outermost diameter of the center member due to the mold release, so that the area of the thin portion is reduced. It is difficult to secure enough, and these also adversely affect the characteristics of the device.

In view of the above facts, an object of the present invention is to provide a vibration damping device having a simple structure and capable of effectively absorbing vibration in a wide band.

[0008]

According to the present invention, an outer cylinder connected to one of a vibration generating portion and a vibration receiving portion, a center member connected to the other of the vibration generating portion and the vibration receiving portion, and the outer cylinder. A vibration-damping device comprising: a rubber-like elastic body interposed between the center member and the center member; and a liquid chamber in which the rubber-like elastic body is part of a partition wall and a liquid is sealed. A cutout recess is provided in the rubber-like elastic body portion opposite to the liquid chamber so that a part of the rubber-like elastic body facing the liquid chamber becomes a thin thin portion, and the cutout recess is It is formed so as to be opened at least outward in the direction orthogonal to the axis.

[0009]

According to the above-mentioned structure of the present invention, when the vibration is transmitted from the vibration generating portion side to the center member or the outer cylinder, the elastic body is deformed and a pressure change occurs in the liquid in the liquid chamber. As a result, the vibration is damped and it becomes difficult to transmit the vibration to the vibration receiving portion side. Further, since the elastic body forming the partition wall of the liquid chamber has a thin portion formed by the notched concave portion,
Even when a high-frequency vibration that cannot be damped by the elastic body and the liquid is transmitted from the vibration generating portion side, this thin portion is elastically deformed to become a low dynamic spring, and it becomes difficult to transmit the vibration to the vibration receiving portion side.

Further, since the cutout recess is formed on the outer side of the elastic body rather than on the liquid chamber side, the amount of the liquid enclosed in the liquid chamber does not increase and is small compared to when the recess is formed on the liquid chamber side. It is possible to reduce the weight. Further, since the cutout recess is formed so as to be opened at least outward in the direction orthogonal to the axis, it is difficult for foreign matter to collect in the cutout recess, and even if foreign matter enters, it is easily discharged and proper vibration damping cannot be performed. There is no fear. Further, the die can be easily removed at the time of vulcanization molding of the elastic body, and the production is simple.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

In the embodiment shown in FIG. 1, the center portion of the steel-made substantially conical center member 12 forming the upper side of the vibration isolator 10 has an anti-vibration device 10 for an engine (not shown).
Is provided with a bolt hole 12B for connecting and fixing. The periphery of the lower side of the center member 12 is a tapered wall portion 12A. On the other hand, the outer cylinder 14 is made of a steel plate and has a cylindrical shape. Then, the center member 12 is arranged at a position on the central axis line radially inward of the outer cylinder 14 and at a position deviated in the axial direction. A lid member 16 made of a steel plate is caulked and fixed to the lower opening of the outer cylinder 14, and the lid member 16 has a bolt 16A and is attached to a body member (not shown) by the bolt 16A. Therefore, the outer cylinder 14 is connected to the vehicle body side by being integrally assembled and fixed to the lid member 16.

Further, between the center member 12 and the outer cylinder 14, an elastic body 18 made of rubber and having a substantially truncated cone shape is disposed. That is, the elastic body 18 is vulcanized and attached to the wall portion 12A of the center portion 12 at its central portion, and vulcanized and adhered to the upper inner peripheral side of the outer cylinder 14 at the lower peripheral edge portion of the elastic body 18. It is installed. A lower surface 18A of the elastic body 18 is configured as a part of a partition wall of the liquid chamber as described later, and the elastic body 18 is extended in a film shape from a portion fixed to the outer cylinder 14 to a lower end of an inner circumference of the outer cylinder 14. There is.

The elastic body 18 is vulcanized and molded so that a cutout recess 20 is formed in a part of the inclined surface 18B. The notched concave portion 20 is composed of a standing wall portion 20A that stands up along the center member 12 and a bottom surface 20B that extends along the axis orthogonal direction.

As shown in FIG. 2, the bottom surface 20B has a substantially fan shape in which one side is a circular arc and is expanded from the inside toward the outside toward the one side, whereby the cutout recess 2 is formed.
0 is opened radially outward. Further, the inner side of the bottom surface 20B has an outermost diameter of the center member 12 (the bolt hole 12B).
It is formed so as to enter the central axis side more than the diameter of the forming portion side). Further, the bottom surface 20B is formed to be a surface parallel to the lower surface 18A. Therefore, the elastic body 18 between the both surfaces is formed to have a small wall thickness and a thin wall portion 22.
It has become. In this embodiment, the thin portion 22 has a thickness of 2
It is formed to ~ 4 mm. On the other hand, the standing wall portion 20A is formed so as to rise along the center member 12 on the inner side of the bottom surface 20B and rise substantially vertically except on the inner side and the arc side portion.

A diaphragm 24 made of a rubber film is attached to the lower end of the outer cylinder 14 so as to cover the opening thereof. The closed space surrounded by the elastic body 18, the outer cylinder 14 and the diaphragm 24 is provided with a liquid chamber 26 in which a liquid such as water or ethylene glycol is enclosed. Further, in the liquid chamber 26, a partition plate 28 made of a synthetic resin and formed in a disc shape is arranged. The partition plate 28 divides the liquid chamber 26 into a pair of liquid chambers, that is, a pressure receiving liquid chamber 26A and a sub liquid chamber 26B. Further, a peripheral groove having a U-shaped cross section is formed on the peripheral edge of the partition plate 28, and when the partition plate 28 is assembled inside the outer cylinder 14, the opening of the peripheral groove is the inner peripheral wall surface of the outer cylinder 14. By being closed by, the limiting passage 30 which is a ring-shaped space is formed.
The limiting passage 30 is formed around the partition wall plate 28 over a half circumference or almost the entire circumference, and one end thereof communicates with the pressure receiving liquid chamber 26A by a through hole 30A.
The other end communicates with the sub liquid chamber 26B through the through hole 30B.

The partition plate 28 is formed with a support portion 28A which projects outward in the radial direction. The support portion 28A together with the peripheral edge portion of the diaphragm 24 and the flange portion 14 of the outer cylinder 14.
It is clamped and fixed by A and the lid member 16. Diaphragm 24
A space between the lid member 16 and the lid member 16 is an air chamber 32, and the diaphragm 24 can be deformed.

FIG. 3 is for explaining the production of the elastic body 18 by vulcanization molding. The molding die 34 is an upper molding die 34.
A, a molding die 34B, a molding die 34C, a lower molding die 34D, a molding die 34E, and a molding die 34F, which are configured to be slidable relative to each other as indicated by arrows in the figure. There is. In addition, in order to form the cutout recess 20 in the molding die 34B, a projection 35 corresponding to the cutout recess 20 is formed. At the time of molding, the outer cylinder 14 and the center member 12 are set in a molding die, and in this state, the elastic material is injected into the space surrounded by the molding dies from an introduction path (not shown) and then heated. Vulcanization molding is performed.

Next, the operation of this embodiment will be described.

When the engine mounted on the center member 12 operates, the vibration of the engine is transmitted to the elastic body 18 via the center member 12. The elastic body 18 acts as a vibration absorbing body, and can absorb vibration by a vibration damping function based on internal friction of the elastic body 18. Further, the elastic body 18
The pressure receiving liquid chamber 26A expands and contracts in accordance with the deformation of the pressure receiving liquid chamber 26A.
As the pressure change occurs in the liquid in A, the liquid passes through the restriction passage 30 and flows between the pressure receiving liquid chamber 26A and the sub liquid chamber 26B expandable / contractible by the diaphragm 24, and the liquid is restricted. The damping effect based on the liquid column resonance of the liquid generated in the passage 30 can improve the vibration damping effect.

Even when the restriction passage 30 is clogged, the thin portion 2 provided in the elastic body 18 against vibrations in a high frequency range of about 200 Hz or higher, for example.
Due to the deformation of 2, the low dynamic spring coefficient and the pressure receiving liquid chamber 26A
The rise of hydraulic pressure inside is prevented, and it becomes difficult to transmit vibration to the vehicle body side.

Further, with the above-described structure, the notch recess 20 for forming the thin portion 22 is formed not on the liquid chamber 26 side of the elastic body 18 but on the outer side thereof. Compared to forming the concave portion, the amount of the liquid sealed in the liquid chamber 26 does not increase, the increase in weight can be prevented, and the cost does not increase. Further, the notch recess 20 is provided so as to be opened outward in the direction orthogonal to the axis, and foreign matter is unlikely to collect in the notch recess, and even if foreign matter enters, it is easily discharged, and there is a danger that proper vibration damping cannot be performed. Absent. In particular, it is suitable when used in a state rotated 90 degrees counterclockwise from the state of FIG. Further, since the cutout recess 20 is provided so as to be opened outward in the direction orthogonal to the axis, and the depth does not expand from the outside to the inside in the direction orthogonal to the axis, the elastic body is vulcanized and molded. At times, die cutting can be easily performed in the direction orthogonal to the axis, and the manufacturing is simple.

Although the center member 12 is connected to the engine and the outer cylinder 14 side is connected to the vehicle body in the above-mentioned example, the reverse structure may be adopted. Further, the notch concave portion may be formed by an inner wall surface that is parallel or outwardly widened in the direction orthogonal to the axis, or may be formed so as to be opened in the axial direction. Also,
In the above-mentioned example, the purpose is to prevent the engine mounted on the vehicle from vibration, but it goes without saying that the vibration control device of the present invention can be used for other purposes as well, and the shape of the members and the like are also different from those of the embodiment. It is not limited to ones.

[0024]

As described above, according to the present invention, the above-described structure facilitates manufacturing with a simple and inexpensive structure, can prevent foreign matter from entering and staying, and effectively vibrates in a wide band. The excellent effect that it can be absorbed occurs.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention.

FIG. 2 is a plan view showing an embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view illustrating the production of a rubber-like elastic body according to an example of the present invention.

FIG. 4 is a vertical cross-sectional view showing a conventional technique.

FIG. 5 is a vertical sectional view showing a conventional technique.

FIG. 6 is a vertical cross-sectional view showing a conventional technique.

FIG. 7 is a vertical sectional view showing a conventional technique.

[Explanation of symbols]

 12 Center Member 14 Outer Cylinder 18 Elastic Body 20 Notch Recess 22 Thin-walled Part 24 Diaphragm 26A Pressure-receiving Liquid Chamber (Liquid Chamber) 26B Sub-Liquid Chamber (Liquid Chamber)

Claims (1)

[Claims] 1. An outer cylinder connected to one of the vibration generator and the vibration receiver, a center member connected to the other of the vibration generator and the vibration receiver, and between the outer cylinder and the center member. An anti-vibration device comprising a rubber-like elastic body interposed and a liquid chamber in which the rubber-like elastic body is part of a partition wall and liquid is sealed, wherein the rubber-like elastic body faces the liquid chamber. A cutout recess is provided in the rubber-like elastic body portion on the side opposite to the liquid chamber so that a part of the body becomes a thin and thin portion, and the cutout recess extends at least outward in the direction orthogonal to the axis. The anti-vibration device is characterized in that it is recessed so as to be opened.