JPH0735841B2 - Anti-vibration device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vibration isolation device interposed between a vibration generating portion and a vibration receiving portion, and in particular, a liquid is enclosed and its flow resistance absorbs vibration. Regarding a vibration control device.

[Background technology]

2. Description of the Related Art As a vibration isolation device used for automobile engine mounts, cab mounts, body mounts, and the like, there is one that has a liquid chamber partially formed of an elastic body. This liquid chamber is divided into a plurality of small liquid chambers by a partition wall, and these small liquid chambers are connected by an orifice.

Therefore, the vibration is absorbed by the resistance when the liquid in one small liquid chamber moves toward the other small liquid chamber through the orifice when the vibration occurs.

However, in such a vibration isolator, in order to cope with vibrations of different frequencies generated in an automobile or the like, it is necessary to provide a plurality of orifices of different sizes and to open and close them by valves or the like.

A vibration damping device that changes the viscosity of the liquid according to the load by applying an electric field has also been proposed (JP-A-60-104828 and JP-A-61-74930), but the orifice is short and the damping is sufficient. Can't get

In view of the above facts, the present invention has an object to obtain a vibration isolator that can easily absorb vibrations of different frequencies.

[Outline and Action of Invention]

The vibration control device of the present invention includes a first member connected to either one of the vibration generating unit and the vibration receiving unit, and a second member connected to the other of the vibration generating unit and the vibration receiving unit. An elastic body which is provided between the first member and the second member and elastically deforms when vibration is generated, a main liquid chamber which can be expanded and contracted by using the elastic body as a part of a partition wall, and the main liquid chamber. And a sub-liquid chamber that is isolated by a partition member, and a long orifice that is parallel to a surface of the partition member that receives pressure from the main liquid chamber and that has a flow direction of a circular arc. An electrorheological fluid filled in the main liquid chamber, the sub liquid chamber, and the long orifice, and along a direction intersecting a surface of the inner wall surface of the long orifice that receives pressure from the main liquid chamber. An electric field for applying an electric field to the electrorheological fluid in the long orifice. It is characterized by having a and.

This electrorheological fluid is also disclosed in, for example, US Pat. Nos. 2,88,615 and 3,047,507, and the viscosity thereof increases according to the strength of the electric field.

As described above, according to the present invention, the electrodes are energized to change the viscosity of the electrorheological fluid in the long orifice to adjust the flow resistance, so that vibrations of different frequencies can be dealt with.

Example of Invention

FIG. 1 shows a vibration damping device to which the first embodiment of the present invention is applied. The base plate 10 of this anti-vibration device has a mounting bolt 12 projecting from the center lower part thereof, and is fixed to the body of an automobile as an example.

Around the base plate 10 is a cylindrical standing wall portion 10A bent at a right angle, and an upper end portion of the standing wall portion 10A is a flange portion 10B bent at a right angle to the outside. The diaphragm 16 and the partition wall 20 are mounted on the flange portion 10B. An air chamber 22 is formed between the diaphragm 16 and the base plate 10. The air chamber 22 may communicate with the outside if necessary.

The periphery of the partition wall 20 and the diaphragm 16 are caulked and fixed to the flange portion 10B by the lower end portion of the outer cylinder 24. The inner diameter of the upper end of the outer cylinder 24 is gradually increased, and the outer periphery of the vibration absorbing body 26 is vulcanized and adhered. The vibration absorbing body 26 is formed of rubber as an example, the lower end portion is an extension portion 26A extending along the inner circumference of the outer cylinder 24, and a part of the extension portion 26A includes the outer cylinder 24 and the partition wall 20. Is sandwiched between.

The outer periphery of the support base 28 is vulcanized and adhered to the axial center of the vibration absorbing body 26. Mounting bolts protruding from the axis of this support base 28
Reference numeral 30 is for fixing an engine (not shown) mounted on the support base 28.

The vibration absorbing main body 26 forms a liquid chamber 32 together with the outer cylinder 24 and the diaphragm 16, and the liquid chamber 32 is filled and filled with an electrorheological fluid (not shown). As the electrorheological fluid, for example, a mixture of 40 to 60% by weight of silicic acid, 30 to 50% by weight of a low boiling organic phase, 50 to 10% by weight of water, and 5% by weight of a dispersion medium can be applied. , For example, isododecane (isododeka
n) can be applied. This electrorheological fluid has the viscosity of ordinary hydraulic fluid when it is not energized, and has the characteristic that when it is energized, its viscosity changes according to the electric field strength and becomes hard.

As shown in FIG. 2, a through hole 36 is formed in the raised portion 20A formed in the central portion of the partition wall 20. The through hole 36 is closed by a partition cover plate 38 that is fixed to the raised portion 20A by heat welding, high frequency welding or the like. Therefore, the liquid chamber 32 is
The partition cover plate 38 divides into an upper small liquid chamber 32A and a lower small liquid chamber 32B.

A groove having a substantially C-shaped plan is formed in the raised portion 20A, and the opening portion is closed by the partition cover plate 38 to close the orifice 40A.
Has become. The orifice 40 communicates with the upper small liquid chamber 32A and the lower small liquid chamber 32B at longitudinal ends via a circular hole 42 formed in the partition cover plate 30 and a circular hole 44 penetrating the partition 20.

Therefore, the liquid in the upper small liquid chamber 32A and the liquid in the lower small liquid chamber 32B can mutually flow through the orifice 40 and generate resistance when passing.

Electrode plates 46 and 48 are concentrically adhered to the inner peripheral facing surfaces of the orifice 40, that is, the side walls. These electrode plates 46,
Reference numeral 48 is connected to a power source and control circuit (not shown) by lead wires 50 and 52 passing through the inside of the partition wall 20 as shown in FIG. 1, and is energized when necessary.

The partition wall 20 in which the lead wires 50 and 52 are enclosed needs to be partially or wholly made of an insulating material such as synthetic resin or ceramics. As an example, the interval between the electrode plates 46 and 48 is about 1 to 2 mm.

Next, the operation of this embodiment will be described. The base plate 10 is fixed to a vehicle body (not shown) via the mounting bolts 12, and the engine mounted on the support base 28 is fixed by the mounting bolts 30.

The vibration generated in the engine is mainly absorbed through the support base 28.
The vibration is absorbed by the internal friction of the vibration absorbing body 26.

Further, since this vibration is transmitted to the liquid chamber 32 via the vibration absorbing body 26, the electrorheological fluid in the liquid chamber 32 moves through the orifice 40, and the vibration is absorbed by the passage resistance during this movement.

Next, engine vibration occurs over a wide range of frequencies, and accordingly, the electrode plates 46, 48 are connected via the lead wires 50, 52.
Energize to This causes the liquid in the orifice 40 to gradually increase its viscosity. Therefore, if the energization amount is controlled according to the vibration absorption frequency, it is possible to absorb the vibration over a wide range.

In particular, since the orifice 40 has a long axial dimension, it can cope with the case where engine vibration occurs over a wide range.

Specifically, applying this embodiment to an engine mount, the bouncing vibration of the engine is 15 Hz and the rolling vibration is 7H.
May occur around z. On the other hand, the anti-vibration device does not energize the electrode plates 46 and 48, but tunes the viscosity of the fluid so as to match the bouncing vibration of the engine, and when rolling vibration occurs, energizes the electrode plates 46 and 48 to cause a gap between the electrodes. By increasing the viscosity of the fluid by applying a potential difference, the peak position of high attenuation can be shifted to around 7Hz.

FIG. 3 shows a second embodiment of the present invention.

In this embodiment, the outer circumference of the partition cover plate 30 in the above embodiment is bent at a right angle to form a cylindrical standing wall portion 38A that is in contact with the outer circumference of the raised portion 20A, and the lower end portion of the standing wall 38A is bent at a further right angle. Flange portion 38B, which is in close contact with the upper surface of the partition wall 20, and is pressed against the partition wall 20 by the lower end caulking portion of the outer cylinder 24. Therefore, in this embodiment, the upper end of the partition wall 20 and the partition wall cover plate
It is possible to form a leak-free orifice 40 by surely closing the gap with 38.

FIG. 4 (A) shows a third embodiment of the present invention.
In this embodiment, an opening 56 is formed at the center of the partition cover plate 38, and a movable plate 58 is mounted in this opening 56. The movable plate 58 has an enlarged diameter portion 58A at the end on the side of the upper small liquid chamber 32A, and a stopper plate 60 is fixed to the side of the lower small liquid chamber 32B. The outer diameter of the movable plate 58 and the stopper plate 60 is formed larger than the opening 56, and the distance between the movable plate 58 and the stopper plate 60 is larger than the wall thickness of the partition cover plate 38. Therefore, the movable plate 58 can be slightly displaced (about 0.5 mm or less) in the thickness direction of the partition cover plate 38.

Therefore, in this embodiment, it is possible to absorb a wide range of vibrations by utilizing the viscosity change of the electrorheological fluid due to the energization of the electrode plates 46 and 48, and the movable plate 58 can vibrate, so that particularly high frequency minute vibrations can be generated. Even when receiving it, the dynamic spring constant is not increased, and therefore the muffled noise can be reduced.

FIG. 4 (B) shows a fifth embodiment of the present invention.
In this example, a member that can be slightly displaced similarly to the above-described embodiment is provided, but the iron plate 103 that can be minutely displaced has a plurality of small holes and is sandwiched between the elastic films 101 and 102. The elastic films 101 and 102 are vulcanized and bonded to the partition cover plate 38 and the partition wall 20, and have a gap with the iron plate 103 so that the iron plate 103 can be slightly displaced. Other configurations are similar to those of FIG. 4 (A), and similar effects can be obtained.

FIG. 5 shows a fifth embodiment of the present invention.

In this embodiment, in addition to the vibration isolator of the first embodiment, an upper small liquid chamber
A partition plate 62 is arranged in 32A. This partition plate 62 is arranged at approximately the central portion of the upper small liquid chamber 32A, and the periphery is a standing wall portion 62A bent substantially at a right angle, and the lower end portion of the standing wall portion 62A is further bent at a right angle with a flange portion 62B. The flange portion 62B is pressed and fixed to the partition wall 20 by the lower end portion of the outer cylinder 24. An opening 64 is formed in the center of the partition plate 62.

Therefore, this partition plate 62 divides the upper small liquid chamber 32A into almost two,
The openings 64 communicate with each other.

As a result, in this embodiment, in addition to the first embodiment, the opening
The liquid column resonance generated near 64 can be used to further lower the dynamic spring constant at a specific frequency.

FIG. 6 shows a sixth embodiment of the present invention.

In this embodiment, a plurality of (four in this embodiment) concentric electrode plates 66, 68, 70, 7 are inserted into the through holes 36 in the first embodiment.
Two are provided. These are supported by an arm 74 that is stretched over the through hole 36. Further, the electrode plate 66 and the electrode plate 70 are connected to a control device and a power source (not shown) by a lead wire 76 passing through the arm 74 and the partition wall 20, and the electrode plates 68 and 72 by a similar lead wire 78.

In addition, a through hole 38C communicating with the through hole 36 is formed in the partition cover plate 38, whereby the through hole 38C communicates with the through hole 36, the upper small liquid chamber 32A and the lower small liquid chamber 32B.

The intervals between the electrode plates 66 and 72 are set to be approximately the same as the intervals between the electrode plates 46 and 48.

Therefore, in this embodiment, the upper small liquid chamber is connected through the through holes 36 and 38C.
The cross-sectional area Sa of the orifice connecting the lower fluid chamber 32B and the small fluid chamber 32B is larger than Sb of the orifice 40, and the through hole 38
The length of the orifice at C, 36 is shorter than that of the orifice 40.

At the time of absorbing vibration, the viscosity of the fluid in the orifice 40 and the through holes 38C, 36 is varied by energizing the electrode plates 46, 48 and the electrode plates 66 to 72 to change the viscosity of the fluid in the orifice 40 and the through holes 38C, 36.
Various kinds of vibrations can be absorbed by the combination of orifices. In order to reduce the muffled noise at high speed, it is preferable that the fluid can freely pass through the orifices of the through holes 36, 38C. In particular, it is also possible to solidify the fluid in the through holes 38C and 36 and substantially connect the upper small liquid chamber 32A and the lower small liquid chamber 32B only by the orifice 40. In this case, if the electrode plates 46, 48 are not energized, the orifice 40 has the same characteristics as an orifice without the electrode plates 46, 48.

As a specific example, when the bouncing vibration of the engine is around 15 Hz and the pitching vibration is around 7 Hz, it is generally impossible to produce a high damping at a deviated frequency. Therefore, the diameter and length of the orifice 40 are determined so that the frequency peak of the damping force is tuned to 15 Hz when no potential difference is applied to the electrodes 40 and 48 of the orifice 40. By applying an electric field between them, it becomes possible to increase the viscosity of the fluid and bring the peak of the damping force to around 7 Hz. In this case, a potential difference is applied to the electrode plates 66 to 72 to solidify the fluid in this portion of the orifice.

Further, if the fluid in the orifice 40 is solidified, the spring constant can be considerably hardened. This can be applied when the spring constant is temporarily hardened to prevent the engine from interfering with other parts when a high load is suddenly applied.

It is preferable that the ratio L / S of the length L of the orifice and the cross-sectional area S in the orifice portion of this embodiment is 2 or more.

FIG. 8 shows a seventh embodiment of the present invention, in which an elastic body 105 is further attached to the upper part of the support base 28 and is vulcanized and adhered to a plate 106 to which a bolt 30 is fixed. As a result, the fluid stops flowing through the orifice 40, and the small upper fluid chamber 32A
The increase in spring constant when the internal pressure rises is reduced.

〔The invention's effect〕

As described above, the vibration damping device of the present invention can change the viscosity of the electrorheological fluid in the long orifice by energizing the electrodes provided in the long orifice that communicates the main liquid chamber and the sub liquid chamber. Therefore, there is an excellent effect that the vibration can be absorbed over a wide range.

In addition, the long orifice is parallel to the surface that receives pressure from the main liquid chamber and the fluid flow direction is arcuate, so the long orifice can be lengthened without changing the distance between the main liquid chamber and the sub liquid chamber. It has an excellent effect that a large damping effect can be obtained.

Further, since the electrode is provided in a portion of the inner wall surface of the long orifice along the direction intersecting the surface receiving the pressure from the main liquid chamber, even if the partition member is deformed by the pressure from the main liquid chamber, the electrode is Since there is almost no dimensional change between them, it has an excellent effect that the vibration control device can be accurately controlled.

[Brief description of drawings]

1 is a vertical sectional view showing a vibration isolator according to a first embodiment of the present invention, FIG. 2 is an exploded perspective view showing a partition wall portion of FIG. 1, and FIG. 3 is a second embodiment of the present invention. The longitudinal sectional view corresponding to FIG. 1 and FIGS. 4A and 4B are respectively the third and the third of the present invention.
4 is a vertical sectional view showing the fourth embodiment, FIGS. 5 and 6 are vertical sectional views showing the fifth and sixth embodiments of the present invention, and FIG. 7 is a VI of FIG.
Fig. 8 is a sectional view taken along the line I-VII, and Fig. 8 is a longitudinal sectional view showing a seventh embodiment of the present invention. 16 ... Diaphragm, 20 ... Partition, 26 ... Vibration absorption main, 32 ... Liquid chamber, 32A ... Upper small liquid chamber, 32B ... Lower small liquid chamber, 38 ... Partition cover plate, 40 ... Orifice, 46,48,66,68,70,72 ... Electrode plate.

Claims (1)

[Claims] 1. A first member connected to either one of the vibration generating section and the vibration receiving section, a second member connected to the other of the vibration generating section and the vibration receiving section, and the first member. And an elastic body that is elastically deformed when vibration is generated, a main liquid chamber that is expandable and contractible using the elastic body as a part of a partition wall, and the main liquid chamber is a partition wall. A sub-liquid chamber separated by a member, a long orifice parallel to a surface of the partition member that receives pressure from the main liquid chamber, and a liquid flow direction is an arc shape, the main liquid chamber, the The electro-rheological fluid filled in the sub liquid chamber and the inside of the long orifice, and provided in a portion of the inner wall surface of the long orifice along a direction intersecting a surface receiving the pressure from the main liquid chamber, An electrode for applying an electric field to the electrorheological fluid in the long orifice, Anti-vibration device characterized by that.