JPH0218453B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a vibration isolator for reducing vibrations from a vibration source.

[Background Art] A vibration isolating device, generally called a vibration isolating rubber, is used, for example, in an engine mount of an automobile to absorb vibrations from the automobile engine and prevent the vibrations from being transmitted to the vehicle body.

Two vibration-damping liquid chambers are provided as this vibration isolator, and the vibration from the vibration source is transmitted as a contraction force to one of the liquid chambers, and when the liquid in this liquid chamber is moved to the other liquid chamber through the restriction passage. A configuration has been proposed in which vibrations are absorbed by a resistance force based on internal friction.

However, in this vibration isolator, when the input vibration is a high frequency of 50 Hz or higher, for example, the amplitude is small, the restriction passage becomes clogged, the internal pressure rises, and the spring constant becomes high. As a result, the transmission rate of vibration increases, causing a worsening of the ride comfort of the vehicle.

[Object of the Invention] Taking the above-mentioned facts into account, the present invention aims to provide a vibration isolating device that can appropriately attenuate even high-frequency vibrations and is capable of damping vibrations over a wide range.

[Summary of the Invention] The vibration isolator according to the present invention uses a hollow chamber mainly formed of a hollow molded body of rubber or rubber-like elastic material as a vibration absorbing body as a liquid chamber, and the liquid chamber is confined inside the liquid chamber. The liquid flow is separated into small liquid chambers through a restriction passage, and the damping effect based on the viscous resistance of the liquid flow generated in this restriction passage is combined with the vibration damping function mainly based on internal friction, which is the main vibration absorber, to buffer vibration. A vibration isolating device is provided, in which a sealed chamber is provided between each of the separated small liquid chambers, this sealed chamber and each of the small liquid chambers are separated by an elastic membrane, and the amount of displacement of the elastic membrane in the direction of contraction of the sealed chamber is By limiting the displacement of the elastic membrane at low frequencies and high amplitudes, vibrations are absorbed in the restriction passage, and at high frequencies and low amplitudes, the volume change of the elastic membrane prevents pressure rise and obtains a low dynamic spring constant. It's summery.

[Embodiments of the Invention] FIG. 1 shows a sectional view of a vibration isolator to which the present invention is applied. This vibration isolator is used as an engine mount, and a mounting bolt 12 is fixed to the center of the bottom plate 10 for mounting to a vehicle body (not shown).

A cylindrical connecting plate 1 is provided on the outer periphery of the bottom plate 10.
The lower end part of 4 is bent and fixed by caulking,
Furthermore, the peripheral edge of a lower diaphragm 16 made of an elastic body is sandwiched between the bottom plate 10 and the connection plate 14. The center of the bottom plate 10 and the lower diaphragm 1
6 constitutes an air chamber 18, and the lower diaphragm 16 is movable in the direction of expansion and contraction of the air chamber 18. Air holes 19 may be provided in the bottom plate 10.

The outer periphery of the lower end of rubber 20, which is a hollow molded body whose axis is perpendicular, is vulcanized and bonded to the upper part of the connecting plate 14. It is also possible to use other elastic materials in place of the rubber 20.

A top plate 22 is fixed to the top of the rubber 20. A mounting bolt 24 is fixed to the center of the top plate 22 for mounting an engine (not shown).

A hollow chamber formed by the rubber 20 and the lower diaphragm 16 is a liquid chamber 26, and this liquid chamber 26 is filled with a liquid such as water.

An air chamber unit 28 forming a sealed chamber is disposed within the liquid chamber 26. This air chamber unit 28 is attached to the bottom plate 10 by a cylindrical body 30 whose lower end is held between the lower diaphragm 16 and the rubber 20, and the outer circumference of a disk 32 is fixed into the cylindrical body 30. has been done. As a result, air chamber unit 2
8 separates the liquid chamber 26 into an upper liquid chamber 26A and a lower liquid chamber 26B, which are small liquid chambers. This disk 32 is the second
As shown in the figure, an orifice 34, which is a ring-shaped restriction passage, is formed on the outer periphery of the axially intermediate portion. This orifice 34 is located in a part of the circumference of the upper liquid chamber 2.
6A and other parts of the lower liquid chamber 26
A notch 38 communicating with B is formed. For this purpose, the upper liquid chamber 2 enters the orifice 34 through the notch 36.
The liquid 6A flows through the notch 38 after rotating the disk 32 by half a turn.
The lower liquid chamber 26B is reached through the lower liquid chamber 26B, and an orifice with a long axial length is obtained.

Also, the upper liquid chamber 26A and the lower liquid chamber 2 of this disc 32
Circular recesses 40, 42 are bored in the surface facing 6B, and the disc 32 has these recesses 40, 4.
A through hole 44 is bored through the axial center of the two. In addition, elastic rubber membranes 46 are provided on the front and back surfaces of the disk 32,
The periphery of 48 is fixed to cover the recesses 40 and 42. Therefore, the recesses 40, 42 and the through hole 44 constitute a sealed air chamber. Also, the recess 4
The thin wall portion of the disc 32 formed between 0 and 42 constitutes a displacement regulating means, and when the elastic rubber membrane 46 or 48 changes by a predetermined amount as shown in FIG. It's getting old. In the vibration isolator of this embodiment configured in this way, the bottom plate 10
is fixed to the body of the automobile via the mounting bolts 12, and the mounting is completed by mounting and fixing the automobile engine onto the top plate 22 using the mounting bolts 24.

When installing the engine, since the weight of the engine acts on the mounting bolt 24, the upper liquid chamber 26A
The pressure in the orifice 34 increases.
The air is transmitted to the lower liquid chamber 26B through the air chamber 18, and the air chamber 18 is contracted.

When the engine is operating, vibrations generated by the engine are transmitted through the top plate 22. The rubber 20 acts as a main vibration absorber, and can absorb vibrations by a damping function based on the internal friction of the rubber 20. Furthermore, if the vibration frequency is low and the amplitude is high, the third
As shown in the figure, the pressure increase in the upper liquid chamber 26A is transmitted to the rubber membrane 46, and this rubber membrane 46 is pressed against the bottom surface of the recess 40. As a result, the vibration damping effect can be improved by the damping effect based on the viscous resistance of the liquid flow generated in the orifice 34. Since the rubber membrane 48 receives the displacement of the rubber membrane 46 through the air chamber, it is displaced in the opposite direction as shown in FIG.

Also, if the engine vibration has a high frequency of, for example, 50Hz or higher, the amplitude is small and the orifice 3
4 may become clogged. In this case, as shown in FIG. 4, the rubber membrane 46 of the air chamber unit 28 receives the pressing force and causes a volume change, thereby preventing a pressure increase in the upper liquid chamber 26A and absorbing vibrations.

In this way, in this embodiment, vibrations can be absorbed over a wide range of frequencies, and the ride comfort of the vehicle can be improved.

Next, FIG. 5 shows a second embodiment of the present invention. In this embodiment, as in the previous embodiment, an upper liquid chamber 26A and a lower liquid chamber 26B are provided, which are separated by an air chamber unit 28 and communicated through an orifice 34. In this embodiment, the center portion of the bottom plate 10 is bent significantly downward to form a large air chamber 18. Further, mounting bolts 12 protrude from the vicinity of the periphery of the bottom plate 10 for fixing it to the vehicle body.

Further, in this embodiment, the connecting plate 14 of the previous embodiment is not provided, and a connecting plate 58 is placed on the bottom plate 10.
is fixed, and this connection flat plate 58 connects to the bottom plate 10.
The lower diaphragm 16 and the cylindrical body 30 are sandwiched between them. Rubber 20 having the same role as in the previous embodiment is vulcanized and bonded onto this connecting plate 58.

Therefore, in this embodiment as well, the same effects as in the previous embodiment can be obtained.

Next, FIG. 6 shows a third embodiment of the present invention. In this embodiment, a lower diaphragm 16 is fixed to the lower end of a cylindrical body 60 having a shape substantially the same as the connecting plate 14 of the first embodiment, and an air chamber unit 28 is fixed to the middle part of this cylindrical body 60. . A weight 16A is fixed to the center of the lower diaphragm 16 to improve frequency characteristics. Also, the cylindrical body 60
A flange 6 having a through hole in the center is attached to the upper end.
2 is fixed to the flange 62, and a rubber 20, which is the main vibration absorber, is fixed to this flange 62. Therefore, in this embodiment, the space between the air chamber unit 28 and the rubber 20 is the upper liquid chamber 26A, and the space between the air chamber unit 28 and the lower diaphragm 16 is the lower liquid chamber 26B.

However, in this embodiment as well, the air chamber unit 28
The configuration is similar to that of each of the embodiments described above, and the same effects can be obtained.

[Effects of the Invention] As explained above, in the vibration isolating device according to the present invention, each small liquid chamber is formed with a sealed chamber separated by an elastic membrane, and the amount of displacement of the elastic membrane is regulated by the displacement regulating means, so that high-frequency vibrations can be suppressed. Therefore, it is possible to obtain a vibration isolating device capable of damping vibrations over a wide range.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of the vibration isolator according to the present invention, FIG. 2 is an exploded perspective view of the vibration isolator unit, and FIGS. 3 and 4 are enlarged operations of the main parts of FIG. 1. FIG. 5 is a longitudinal cross-sectional view showing a second embodiment of the present invention, and FIG. 6 is a longitudinal cross-sectional view showing a third embodiment of the present invention. 20... Rubber, 26... Liquid chamber, 28... Air chamber unit, 30... Cylindrical body, 32... Disc, 34... Orifice, 40, 42... Recess, 44... Through hole, 46, 4
8...Rubber membrane.

Claims (1)

[Claims] 1. A hollow chamber mainly for vibration absorption made of a hollow molded body of an elastic material is used as a liquid chamber, and this liquid chamber is separated into small liquid chambers via a passage restricting the flow of liquid confined within the liquid chamber, In a vibration isolating device that uses a damping effect based on the viscous resistance of the liquid flow that occurs in the vibration absorber in combination with a damping function that is mainly based on internal friction to buffer vibrations, a sealed chamber is provided between each of the separated small liquid chambers. A vibration isolating device characterized in that the sealed chamber and each of the small liquid chambers are separated by an elastic membrane, and a displacement regulating means regulates the amount of displacement of the elastic membrane in the direction of contraction of the sealed chamber.