JPH0425638A - Vibration isolator - Google Patents

Abstract

PURPOSE:To ameliorate the extent of durability in an elastic body as well as to improve the durability of a vibration isolator in particular by segregating the elastic body, forming a liquid chamber, from a liquid being filled up in this liquid chamber through an isolating body. CONSTITUTION:Since an isolating film 50 is made up of a rubber film of butyl rubber, it is expanded or contracted together with absorbent rubber 22 even if this rubber is elastically deformed by vibration. Then, a liquid chamber 28 is formed by this isolating film 50 and a diaphragm 18, and an electroviscous fluid is charged into this liquid chamber 28. Thus, since the absorbent rubber 22 is isolated by the film 50, such a fear that the electroviscous fluid 29 extracts an additive agent mixed in the absorbent rubber 22 and thereby deteriorate this rubber in terms of quality is brought to bothing. In consequence, since it is possible to use this absorbent rubber 22 consisting of an optimum material to applications of a vibration-isolator 1 to be used, both absorbent and endurant properties are improbable in particular.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a vibration damping device that is provided between a vibration generating part and a vibration receiving part of a vehicle or general industrial machine, and absorbs vibrations from the vibration generating part. Regarding equipment.

[Prior Art] A vibration isolator, which serves as an engine mount, is used in an automobile to absorb engine vibrations between the engine and the vehicle body.

An elastic body mainly made of natural rubber is disposed inside this vibration isolator, and an expandable and contractible liquid chamber is provided in which the elastic body forms part of a partition wall. This liquid chamber is divided into a plurality of small liquid chambers, and these small liquid chambers are communicated with each other by a restriction passage.

In this vibration isolator, when engine vibration is applied to one small liquid chamber, passage resistance and liquid column resonance occur when the liquid in one small liquid chamber moves to the other small liquid chamber via the restriction passage. Vibrations are absorbed.

Incidentally, some of the above-mentioned vibration isolators may use a special liquid other than ordinary ethylene glycol or the like. For example, electrorheological fluid whose viscosity changes depending on the magnitude of the electric field applied to the liquid chamber is used as a vibration isolator that aims to effectively absorb vibrations with different frequencies over a wide range of frequencies. Some attempts have been made to effectively absorb vibrations over a wide range by filling the restriction passage with electrodes and adjusting the flow rate of the electrorheological fluid passing through the restriction passage according to the vibration frequency.

However, depending on the composition of the electrorheological fluid, there is a possibility that additives and the like contained in the elastic body constituting the wall of the liquid chamber may be extracted and deteriorate the elastic body.

[Problems to be Solved by the Invention] Taking the above-mentioned facts into account, the present invention isolates an elastic body from a liquid that may deteriorate the elastic body forming the liquid chamber and the chamber wall, such as an electrorheological fluid. The purpose of this invention is to provide a vibration isolator with excellent durability.

[Means for Solving the Problems] The present invention as set forth in claim (1) includes: a first member connected to one of a vibration generating section or a vibration receiving section; a second member connected to the other; an elastic body provided between the first member and the second member to absorb vibration; a liquid chamber in which the elastic body forms at least a part of the chamber wall; and a liquid filled in the liquid chamber; The present invention is characterized in that it includes a separator that covers the elastic body and separates the liquid and the elastic body.

The present invention according to claim (2) is characterized in that the liquid is an electrorheological fluid whose viscosity changes depending on the magnitude of the applied electric field.

[Function] In the present invention as set forth in claim (1), the elastic body constituting the chamber wall of the liquid chamber that expands and contracts due to vibration is covered with a separator, so that the liquid filled in the liquid chamber and the elastic body are covered. and are isolated.

Therefore, the elastic body will not deteriorate due to the influence of the liquid.

As a result, it is possible to improve the durability of the elastic body and further improve the durability of the vibration isolator.

In the present invention as set forth in claim (2), the elastic body constituting the chamber wall of the liquid chamber that expands and contracts due to vibration is covered with a separator, and the electrorheological fluid filled in the liquid chamber and the elastic body are separated. is isolated.

Therefore, the elastic body does not deteriorate due to the influence of the electrorheological fluid.

[First Embodiment] FIGS. 1 and 2 show an embodiment of a vibration isolating device 10 according to the present invention.

As shown in FIG. 1, a mounting bolt 14 is protruded from the center of the bottom plate 12 of the vibration isolator 10, and is adapted to be fixed to the body of an automobile (not shown), for example.

The outer peripheral part of the bottom plate 12 is a cylindrical vertical wall part 1 bent at a substantially right angle.
2A, and a flange portion 12B having a raised portion 12C bent at a substantially right angle is continuously formed at the upper end of this standing wall portion 12A.

This flange portion 12B has an outer cylinder 1 fixed to the bottom plate 12.
A flange portion 16A formed at the lower end portion of 6 is fixed by caulking. The flange portion 12B and the flange portion 16A
A diaphragm 1 formed of a thin film-like rubber material is provided between the
80 peripheral edge portion 18A is sandwiched. An air chamber 20 is formed between the diaphragm 18 and the bottom plate 12.

The air chamber 12 may be communicated with the outside air by forming a through hole or the like in the bottom plate 12.

A cylindrical portion 16C formed at an axially intermediate portion of the outer cylinder 16 has an expanded portion 16B whose inner diameter is gradually enlarged on the opposite side from the flange portion 16A. The outer periphery of the vibration-absorbing rubber 22 is vulcanized and bonded to this expanded portion 16B. The vibration absorbing rubber 22 is made of a natural rubber (NR) rubber material that has excellent dynamic characteristics and durability.

The outer circumferential portion of the support base 24 is vulcanized and bonded to the inner circumferential portion of the vibration absorbing rubber 22 . The support stand 24 is a mounting part for an engine (not shown), and has mounting bolts 26 protruding therefrom.
The engine is now fixed.

An isolation membrane 50 serving as a thin membrane-like isolation body is adhered to a portion of the cylindrical portion 16C and flange portion 16A of the outer cylinder 16 and to the inner peripheral surface of the vibration absorbing rubber 22. This isolation membrane 50
is formed from a rubber film based on butyl rubber (for example, inbutylene rubber or isoprene rubber). Since the isolation membrane 50 is made of a rubber material, it can expand and contract together with the vibration absorbing rubber 22 even if the vibration absorbing rubber 22 expands and contracts in response to vibrations.

As shown in FIG. 1, a liquid chamber 28 is formed by the isolation membrane 50 and the diaphragm 18. This liquid chamber 28 is filled with an electrorheological fluid 29 .

An orifice member 30 made of an insulator such as synthetic resin is disposed within the liquid chamber 28, and the liquid chamber 28 is connected to a main liquid chamber 36.
and an auxiliary liquid chamber 38.

The flange portion 3 [IB of the orifice member 30 is clamped and fixed by the flange portion 12B of the bottom plate 12 and the flange portion 16A of the outer cylinder 16 via the peripheral portion 18A of the diaphragm 18 and the isolation membrane 50.

A through hole 32 is formed in the axial center of the orifice member 30 . This through hole 32 is closed by a top plate portion 34 placed on the projection portion 30A of the orifice member 30.

As shown in FIG. 2, the protrusion 30 of the orifice member 30
A C-shaped groove 40 is formed around the axis of the protrusion 30A. The cross-sectional area of the groove 40 is formed relatively large to prevent the electrorheological fluid 29 from clogging even in the case of high frequency vibration. A circular opening 40A is formed in the top plate portion 34 corresponding to one end of the groove 40 and communicates with the main liquid chamber 36, and a circular opening 40B is formed in the orifice member 30 corresponding to the other end. is formed and communicates with the sub-liquid chamber 38. Thereby, the front groove 40 communicates the main liquid chamber 36 and the auxiliary liquid chamber 38, and serves as an orifice 44 as a restriction passage. C-shaped electrode plates 46 and 48 are bonded to the inner peripheral surface of the groove 40 so as to face each other.

As shown in FIG. 1, these electrode plates 46 and 48 have lead wires 46A passing through the inside of the orifice member 30,
48A to a high voltage generation circuit (not shown), and is energized as necessary.

The electrorheological fluid 29 may include, for example, 40 to 60% by weight of silicic acid, 30 to 50% by weight of a low boiling point organic phase, and 50 to 1% by weight of a low boiling point organic phase.
Mixtures consisting of 0% by weight water and 5% by weight dispersion medium can be applied, for example indodecane
n) is applicable. This electrorheological fluid 29 is applied to the electrode plate 46
．． It has the viscosity of a normal hydraulic fluid when it is not energized through 48, and when it is energized, its viscosity changes and becomes hard depending on the electric field strength.

Next, the operation of the embodiment will be explained.

The bottom plate 12 is fixed to a vehicle body (not shown) via mounting bolts 14, and the engine mounted on the support base 24 is fixed using mounting bolts 26.

When engine vibration is transmitted to the mounting bolt 26, it is transmitted to the vibration absorbing rubber 22 via the support base 24, and a portion of the vibration is absorbed by the internal friction of the vibration absorbing rubber 22.

Low-frequency, large-amplitude shake vibrations (frequency: 8-15Hz) that occur when a vehicle travels at a speed of about 70-80 km/h.
At times, the electrode plates 46, 48 are energized. As a result,
The viscosity of the electrorheological fluid 29 within the orifice 44 increases, and the amount of electrorheological fluid 29 flowing through the orifice 44 decreases.

At this time, the shake vibration can be absorbed by the passage resistance of the electrorheological fluid 29 passing through the orifice 44 and by the liquid column resonance occurring within the orifice 44.

In addition, during high frequency and small amplitude idle vibration (20 to 40 Hz) such as idling operation, the electrode plate 46.48
Stop energizing. For this reason, the orifice 44
Since the viscosity of the electrorheological fluid 29 within the main liquid chamber 36 does not increase, a large amount of the electrorheological fluid 29 flows from the main liquid chamber 36 to the sub liquid chamber 38 .

As a result, idle vibrations are absorbed by passage resistance when the electrorheological fluid 29 passes through the orifice 44 and by liquid column resonance occurring within the orifices 4.

By the way, in this embodiment, the vibration absorbing rubber 22 is isolated from the electrorheological fluid 29 by the isolation membrane 50, so the electrorheological fluid 29 extracts additives etc. blended into the vibration absorbing rubber 22, and the vibration absorbing rubber 22 is It doesn't cause any deterioration.

As a result, it is possible to use the vibration absorbing rubber 22 made of the most suitable material depending on the application of the vibration isolator 10 to be used, so that the vibration absorbing performance and durability of the vibration isolator 10 can be further improved.

Note that the isolation membrane 50 is used not only for the vibration absorbing rubber 22 but also for the support base 2.
4. Although the cylindrical portion 16C and part of the flange portion 16A of the outer cylinder 16 have been bonded, it is only necessary that they be bonded to at least the vibration absorbing rubber 22 to prevent the electrorheological fluid 29 from adhering to the vibration absorbing rubber 22.

The isolation membrane 50 does not necessarily have to be made of butyl rubber, but is instead made of a material that is not affected by the electrorheological fluid and can be deformed along with the deformation of the vibration absorbing rubber 22, such as a synthetic resin such as nylon. You may.

Furthermore, the present invention is not limited to the type of vibration isolator described in the embodiments, but may be applied to, for example, a so-called bush type vibration isolator.

In addition, although the example shows a vibration isolator applied as an engine mount, the device is not limited to this and may be applied to a cab mount, body mount, member mount, general industrial vibration isolator mount, etc. Of course.

[Effects of the Invention] As explained above, in the vibration isolating device according to the present invention, the elastic body forming the liquid chamber and the liquid filling the liquid chamber are separated by the isolating body, so that the durability of the elastic body is improved. This has the excellent effect of improving the durability of the vibration isolator and further improving the durability of the vibration isolator.

[Brief explanation of drawings]

1 and 2 show an embodiment of a vibration isolator according to the present invention, with FIG. 1 being a longitudinal sectional view and FIG. 2 being an exploded perspective view of an orifice member. 10... Vibration isolator, 12... Bottom plate (first member), 16... Outer tube (second member), 22... Vibration absorbing rubber (elastic body), 28... Liquid chamber , 29... Electrorheological fluid, 50... Separation membrane (separator). Figure Figure

Claims (2)

[Claims] (1) The first one connected to either the vibration generating part or the vibration receiving part
a second member connected to the other member, an elastic body provided between the first member and the second member to absorb vibrations, and this elastic body forming at least a part of the chamber wall. A vibration isolating device comprising a liquid chamber, a liquid filled in the liquid chamber, and an isolator that covers at least the elastic body and isolates the liquid and the elastic body. (2) The vibration isolator according to claim (1), wherein the liquid is an electrorheological fluid whose viscosity changes depending on the magnitude of the applied electric field.