JPS63158334A - Vibrationproof device - Google Patents

Abstract

PURPOSE:To effectively absorb the compounded vibration of the high and low frequency by forming the first and second communication passages which communicate to a plurality of small liquid chambers and varying the viscosity of the fluid which possesses the electric fluidity through the electric conduction to the electrodes installed in the second communication passage. CONSTITUTION:A liquid chamber 28 is formed from an elastic body 22, outer cylinder 16, and a diaphragm 18, and charged with the fluid 30 which possesses electric fluidity. The liquid 30 possesses the characteristic that the viscosity increases with the intensity of electric field during the electric conduction. Further, the liquid chamber 25 is divided into the upper and lower small liquid chambers 30A and 30B by a partitioning wall 32, and the both liquid chambers communicate each other through the first communication passage 42. Further, the second communication passage 48 is formed onto the partitioning wall 32, and a pair of electrodes 50 and 52 are installed and connected with a voltage loading device 58 and a controller 60. The optimum voltage value is selected by detecting the engine revolution speed and traveling speed. etc., and supplied into the electrodes 50 and 52.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a vibration isolator for absorbing vibrations of automobiles, etc., and particularly relates to a vibration isolator that includes a liquid chamber filled with liquid and absorbs vibrations. Regarding equipment.

[Background technology]

A vibration isolator having a liquid chamber filled with liquid is used (see, for example, Japanese Patent Laid-Open No. 113835/1983). This vibration isolator separates the liquid chamber into multiple small liquid chambers using a partition wall. This partition wall is provided with a communication path that communicates the small liquid chambers. Furthermore, a diaphragm is provided on the partition wall to absorb high frequency vibrations.

Therefore, in this vibration isolator, low frequency vibrations are absorbed by the passage resistance of the communication passage provided in the partition wall, and when the liquid in the communication passage becomes clogged during high frequency vibration, the diaphragm vibrates and absorbs this high frequency. It is supposed to be done.

However, with this vibration isolator, when a so-called compound vibration is applied, in which a high frequency, small amplitude vibration and a low frequency, large amplitude vibration overlap, the diaphragm moves by the maximum amount due to the low frequency vibration included in this compound vibration. There may be cases where the device remains stopped at a certain point, and high frequency vibrations cannot be absorbed.

The present invention takes the above-mentioned facts into account, and aims to provide an anti-JLI device that can appropriately absorb complex vibrations even when they are input.

[Summary and operation of the invention]

A vibration isolator according to the present invention includes a liquid chamber that can be expanded and contracted, a partition wall that partitions the liquid chamber into a plurality of small liquid chambers, a first communication path that communicates the small liquid chambers with each other, and a first communication path that communicates with the small liquid chambers. a second communicating path having a large area; an electrorheological fluid provided corresponding to at least the second communicating path; and an electrode provided in the second communicating path; It is characterized by having an alternating voltage control n means for changing the viscosity of the fluid fluid.

This electrorheological fluid
C fluid) is also disclosed in, for example, US Pat.

Therefore, in the present invention, the ill! Since the energized electrorheological fluid has a large viscosity, the electrorheological fluid in the second communication path periodically increases its viscosity in accordance with the frequency of the alternating voltage. As a result, low-frequency large-amplitude vibrations with a frequency lower than the frequency of the alternating voltage cannot pass through the second communication path, and high-frequency vibrations higher than the frequency of the alternating voltage pass through the second communication path and are opposed. This leads to the liquid chamber on the side, suppressing a large pressure rise in the liquid chamber and absorbing vibrations.

- For example, the alternating voltage is 100% as the frequency of high frequency vibration.
When fiz is considered to be 1011z as the frequency of low-frequency vibration/motion, an intermediate frequency of 5 0 fiz can be adopted. These low and high frequency vibration frequencies are the frequencies of vibration that are required to be eliminated when using the present invention as an automobile engine mount, cab mount, body mount, and member mount.

[Embodiments of the invention]

FIG. 1.2 shows the first part of the vibration isolator 10 to which the present invention is applied.
An example is shown.

This vibration isolator 10 has a mounting plate 14 hanging down from the center of a base plate 12, and is adapted to be fixed to the body of an automobile.

The upper end of the upright portion 12A bent at a right angle from the periphery of the base plate 12 is a flange portion 12B extending at a right angle in the radial direction.

The lower end portion of the outer cylinder 16 is caulked and fixed to the outer periphery of the flange portion 12B with the outer periphery of the diaphragm 18 interposed therebetween. An air chamber 20 is formed between the diaphragm 18 and the base plate 12, and is communicated with the outside as necessary.

The upper end of the outer cylinder 16 has a tapered diameter, and the outer peripheral end of a substantially cylindrical elastic body 22 is vulcanized and bonded to the inner periphery of this expanded diameter. The diameter of the elastic body 22 is gradually reduced toward the upper end, and the outer periphery of a frame 24 is vulcanized and bonded to the inner periphery of the elastic body 22. A mounting bolt 26 is provided upright on the frame 24, so that an automobile engine (not shown) can be mounted and fixed thereon.

A liquid chamber 28 is formed here by the elastic body 22, the outer cylinder 16, and the diaphragm 18, and a liquid 3 is introduced into the liquid chamber 28.
Filled with 0s. This liquid 30 is an electrorheological fluid.

The electrorheological fluid may include, for example, 40-60% by weight of silicic acid, 30-50% by weight of a low-boiling organic phase, 50-10% by weight of a low-boiling organic phase,
A mixture consisting of 1% by weight water and 5% by weight dispersion medium can be applied, for example, isododecane (1sododecane).
) can be used. This electrorheological fluid is connected to electrodes 72.74
It has a viscosity of zero hydraulic fluid when no current is applied through it, and when electricity is applied, the viscosity changes and becomes hard depending on the electric field strength.

A partition wall 32 is disposed within the liquid chamber 28 to divide the inside of the liquid chamber 28 into an upper liquid chamber 30A and a lower liquid chamber 30B.

As shown in FIG. 3, the outer periphery of both upper and lower ends of the partition wall 32 is held between a lower support plate 34 and a lower support plate 36.

The lower support plate 34 and the lower support plate 36 are connected from the outer periphery to the cylindrical portion 34A.
, 36A are each extended, and these cylindrical portions 34
The lower end portions of A and 36A are bent at right angles to form flange portions 34B and 36B that protrude in the radial direction. These flange portions 34B136B are in close contact with each other and are sandwiched together with the diaphragm 18 between the outer cylinder 16 and the base plate 12.

The cylindrical portion 34A is in close contact with the outer periphery of the partition wall 32, and
A first communicating path 42 is formed between the recessed portion and the concave portion formed approximately half way to the outer periphery of the second portion. This first communication passage 42 has one longitudinal end connected to the upper liquid chamber 3OA through a through hole 44 formed in the cylindrical portion 34A, and the other end connected to the lower liquid chamber 3OA through a through hole 46 formed in the lower support plate 36. It communicates with room 30B. For this reason, this fi! l! J path 42 is the upper liquid chamber 3
0A and the lower liquid chamber 30B communicate with each other to form an orifice.

Further, a pair of semicircular second communicating passages 48 are formed in the partition wall 32, communicating both the upper and lower end surfaces.

A pair of electrodes 50 and 52 are provided in each of the second communication paths on the fourth day.
are attached, and are connected to a voltage load device 58 and a control device 60, which are drive circuits, via conductive wires 54 and 56, respectively. A controller 6 is included in this control device 60.
2 is provided, and the sensor 64 detects the engine speed of the automobile, the running speed of the automobile, acceleration, etc., selects the optimum frequency and voltage value, and supplies the selected frequency and voltage value to the electrodes 50 and 52.

Here, the sum of the fluid passage cross-sectional areas of the pair of second communicating passages 48 is larger than the cross-sectional area of the first communicating passage 42.

Next, the operation of this embodiment will be explained.

The anti-vibration bag H10 is fixed to the body of an automobile using the mounting bolts 14, and the installation is completed by mounting the engine on the frame body 24 using the mounting bolts 26.

When the vibration of the engine is only at a relatively low frequency, the vibration is absorbed by the resistance force when the liquid 30 in the liquid chamber 28, which is moved by the low frequency vibration, passes through the first communication path 42. .

In this case, the control device 60 energizes the electrodes 5o and 52 to harden the liquid in the second communication path 48 and bring it into a substantially closed state.

Furthermore, when the vibration becomes high frequency, the liquid 3 in the first communication path 42
0 is a clogged state, so vibrations cannot be absorbed in this first communicating path 42. However, when the electricity to the electrodes 50, 52 is removed, the liquid 30 moves to the lower liquid chamber 30B through the second communication path 48, so the pressure in the upper liquid chamber 30A does not increase and vibrations are absorbed.

Further, when a complex vibration in which a low frequency vibration and a high frequency vibration are overlapped is input, the control device 60 applies a voltage to the electrodes 50.52 at a frequency intermediate between the low frequency vibration and the high frequency vibration.

Therefore, vibrations with a frequency lower than the voltage frequency are caused by this second
It is not possible to pass through the communication path 48, and high frequency swing J
Only the diaphragm 18 passes through this second communication path 48
transform. As a result, vibrations are absorbed within this second communication path and in the other small liquid chamber through which it passed.

FIG. 4 shows the types of alternating frequency voltages applied by the control device 60.

FIG. 4(A) shows a case where a rectangular wave is applied intermittently, and FIG. 4121(B) shows a case where a triangular wave is continuously applied.

A second embodiment of the invention is shown in FIG. 5.6. In this embodiment, flexible membranes 66, 68 made of rubber or the like are fixed at their peripheral edges to both upper and lower ends of the corner wall 32 of the previous embodiment. The flexible membranes 66 and 68 are surrounded by the lower support plate 3.
4 and the lower support plate 36 to ensure secure attachment. The flexible membranes 66, 68 separate the fluid in the second communication passage 48 from the fluid in the liquid 30.

Therefore, electrorheological fluid can be used only as the fluid in the second communication path 48, and water, oil, etc. can be used as the fluid in the liquid chamber 28.

In order for the flexible ribs 66 and 68 to easily vibrate during high-frequency vibrations, the partition wall 32 can be placed at both the upper and lower ends)! Preferably, a recess 70.72 is provided corresponding to the central portion of the two membranes 66, 68 so that this portion also constitutes a liquid chamber for the electrorheological fluid.

Further, in this embodiment, as shown in FIG.
A large number of electrodes 8 are provided, and each of these has an electrode 5.
0.52 and is connected to the control device as in the first embodiment.

〔Effect of the invention〕

As explained above, the present invention provides a liquid chamber that can be expanded and contracted, a partition wall that divides the liquid chamber into a plurality of small liquid chambers, a first communicating path that communicates the small liquid chambers with each other, and a first communication path that connects the small liquid chambers with each other. A second communicating path having a large area, an electrorheic fluid provided corresponding to at least the second communicating path, an electrode provided in the second communicating path, and the electrorheic fluid being energized by applying current to the electrode. Since it has an alternating voltage control means for changing the viscosity of the liquid, it has an excellent effect of being able to appropriately absorb even when a complex vibration of low frequency vibration and high frequency vibration is input.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the first embodiment of the present invention, FIG. 2 is a plan view showing the partition wall portion of the first embodiment, FIG. 3 is an exploded perspective view of the partition wall portion, and FIG. 4 is an alternating voltage FIG. 5 is a longitudinal sectional view showing a second embodiment of the present invention, and FIG. 6 is a plan view showing a partition wall of the second embodiment. lO...Vibration isolator 16...Outer cylinder 18...Diaphragm 22...Elastic body 28...Liquid chamber 30...Liquid 30A...Upper liquid chamber 30B...Lower liquid chamber 32...・Partition wall 42...First communication path 48...Second communication path 50.52...Electrode 60...Control device 62...Controller 64...Sensor

Claims (1)

[Claims] (1) A liquid chamber that can be expanded and contracted, a partition wall that divides the liquid chamber into a plurality of small liquid chambers, a first communication path that communicates the small liquid chambers with each other, and a larger area than the communication path. a second communication passage;
An electrorheological fluid provided corresponding to at least this second communication path, an electrode provided in this second communication path, and an alternating voltage control means for changing the viscosity of the electrorheological fluid by applying current to the electrode. A vibration isolator having the following.