JPH02176230A - Fluid damper - Google Patents

Abstract

PURPOSE:To readily adjust the vibration damping property of a fluid damper by providing electrodes on the inner peripheral face of a damper case and on the outer peripheral face of a piston, the electrodes opposite to each other via a space between the inner peripheral face of a damper case and the outer peripheral face of a piston, and filling each fluid chamber with an electroviscous fluid which has a Winslow effect. CONSTITUTION:On the inner peripheral face of the damper case 11 of a fluid damper 10 and the outer peripheral face of a piston 12, a pair of electrodes 22, 23 are provided respectively which are opposite to each other while sandwiching a space 21 which is formed between the faces and which communicates fluid chambers 13A, 13B with each other, and each fluid chamber 13A, 13B is filled with an electroviscous fluid which has a Winslow effect. By application of voltages between the electrodes 22, 23, an electric field is formed perpendicular to the flow of the electroviscous fluid through the space 21 from the fluid chamber 13A to 13B or its reverse flow so that the viscosity of the electroviscous fluid sandwiched between the electrodes 22, 23 is increased. The viscosity of the fluid moving in the space 21 is thus controlled to enable the vibration damping property of the fluid damper 10 to be adjusted.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to industrial machines such as paper making machines, transportation machines such as vehicles,
The present invention relates to fluid dampers widely used in various other devices.

“Conventional technology” Conventionally, a hydraulic damper uses a working fluid such as oil or air.
A piston is provided within the damper case, and two fluid chambers partitioned by the piston are formed within the damper case,
The piston is provided with an orifice that communicates the two fluid chambers, an operating shaft fixed to the piston extends inside and outside the damper case, and a vibrating body is connected to the operating shaft. [Problems to be Solved] The vibration damping characteristics of the conventional fluid damper described above are fixed depending on the shape of the orifice and the characteristics of the working fluid.

Therefore, if the fluid damper is used in a vibration system that differs from its original design conditions, an optimal vibration damping effect cannot be obtained, and if the fluid damper is used in a vibration system where the vibration state changes over time. In some cases, the vibrations cannot be effectively damped.

In addition, in the conventional fluid damper described above, the gap between the inner peripheral surface of the damper case and the outer peripheral surface of the piston is sealed so that the fluid can move between the two fluid chambers only by passing through the orifice. A sealing member is attached to the outer peripheral surface of the piston. Therefore, the frictional force generated between the seal member and the inner circumferential surface of the damper case acts as resistance to the displacement of the piston, making it difficult to operate the piston smoothly and quickly.

The present invention makes it possible to extremely easily adjust the vibration damping characteristics of a fluid damper, and to enable the piston to operate smoothly and quickly with respect to the damper case, thereby imparting an optimal vibration damping effect to the vibration system. purpose.

[Means for Solving the Problems] The present invention provides a piston in a damper case, forms two fluid chambers partitioned by the piston in the damper case, and connects an operating shaft fixed to the piston to the inside and outside of the damper case. In the fluid damper that extends to the inner circumferential surface of the damper case, a gap is provided between the inner circumferential surface of the damper case and the outer circumferential surface of the piston to communicate the two fluid chambers, and the inner circumferential surface of the damper case and the outer circumferential surface of the piston are each provided with a gap that communicates the two fluid chambers. The electrodes are provided facing each other through the gap, and the two fluid chambers are filled with an electrorheological fluid having a Winslow effect.

[Operation] First, the electrorheological fluid having the Winslow effect, which is essential to the configuration of the present invention, will be explained.

The Winslow effect was introduced in 1947 by W, M, Winsl.
It was first disclosed in U.S. Pat. ) is filled with a so-called electrorheological fluid, and when a voltage is applied between both electrodes, the viscosity of the fluid increases due to the influence of an external electric field. Not only can this viscosity be externally controlled by the magnitude of the external electric field, but it can also be expected to have excellent effects in that it has very good responsiveness.

The electrically insulating liquid used as the "dispersion medium" used in the electrorheological fluid may be any electrically insulating liquid as long as it has a stun property, and is not subject to any particular restrictions.

Examples of this type of electrically insulating liquid include mineral oils and synthetic lubricating oils, and more specifically, naphthenic mineral oils, paraffinic mineral oils, polyalphaolefins, polyalkylene glycols, silicones, diester tripolyol esters, phosphorus Examples include acid esters, silicon compounds, fluorine compounds, polyphenyl ethers, and synthetic hydrocarbons.

The viscosity range of these electrically insulating liquids is 5 at 40°C.
~300 cp is preferred.

Also, porous solid particles as "dispersoids".

Conventional methods are used, and there are no special restrictions.

Porous solid particles of this type include, for example, silica gel, hydrous resins, diatomaceous earth, alumina, silica-alumina, zeolites, ion exchange resins, cellulose, and the like. These porous solid particles typically have a particle size of Ions to
200 tons is used in a proportion of 0.1 to 50 wt%.

"Water" is added to produce an ER (air-viscosity) effect. In particular, it is preferable to adsorb water onto porous solid particles, which are dispersoids, and use the porous solid particles in a manner that facilitates dielectric polarization of the porous solid particles in an electric field. It is used in a proportion of 20 wt%.

The "dispersant" is used to make the state of dispersion of the porous solid particles in the dispersion medium uniform and stable, so a conventional one is used.

Examples of this type of dispersant include sulfonates, phenates, phosphonates, succinimides, amines, esters, nonionic dispersants, and more specifically magnesium sulfonate, calcium sulfonate, and calcium phenate. nate, calcium phosphonate,
Examples include polybutenyl succinimide, sorbitan monooleate, and nrubitan sesquiolate. These are usually used in a proportion of 0.1 to If) rt%. however,
A dispersant may not be used if the solid particles have good dispersibility.

Therefore, in the present invention, electrodes are provided on each of the inner circumferential surface of the damper case and the outer circumferential surface of the piston, and are opposed to each other across a gap that is formed between the two and communicates the two fluid chambers, and the damper Since the two fluid chambers formed inside the case are filled with an electrorheological fluid having a Winslow effect, applying a voltage between the electrodes will increase the viscosity of the electrorheological fluid sandwiched between the two electrodes. . Therefore, the viscosity of the fluid moving from one fluid chamber through the gap to the other fluid chamber is controlled, and as a result, the throttling resistance of the fluid in the gap is adjusted, and the vibration damping characteristics of the fluid damper can be adjusted. Become. In other words, the voltage applied between the two electrodes is determined by the position of the piston relative to the damper case,
By appropriately controlling the speed, direction of movement, etc., the vibration damping characteristics of the fluid damper can be adjusted very easily.

Further, in the present invention, the gap between the inner circumferential surface of the damper case and the outer circumferential surface of the piston is made to function as a fluid passage passage without being sealed with a sealing member attached to the outer circumferential surface of the piston. . Therefore, the conventional frictional force generated between the seal member and the inner circumferential surface of the damper case does not act as resistance to the displacement of the piston, and the piston can operate smoothly and quickly. Moreover, the gap between the inner circumferential surface of the damper case and the outer circumferential surface of the piston, which is not provided with a sealing member, is actively utilized as a control element.

Note that the electrodes of the present invention can be provided over a wide range around the inner peripheral surface of the damper case and the outer peripheral surface of the piston. Therefore, even if a relatively low voltage is applied between both electrodes, the viscosity of a large amount of fluid sandwiched between the two electrodes will change, effectively adjusting the vibration damping characteristics of the fluid damper. It will be possible.

Therefore, according to the present invention, the vibration damping characteristics of the fluid damper can be adjusted extremely easily, the piston can be operated smoothly and quickly with respect to the damper case, and the optimum vibration damping effect can be obtained for the vibration system. can be granted.

[Example] Fig. 1 is a longitudinal cross-sectional view showing one embodiment of the present invention, Fig. 2 is a cross-sectional view of Fig. 1, and Fig. 3 is a longitudinal cross-sectional view showing another embodiment of the present invention. 4 is a cross-sectional view of FIG. 3, FIG. 5 is a sectional view showing a modification of the electrode installation state, and FIG. 6 is a sectional view showing another modification of the electrode installation state.

The fluid damper lO shown in FIGS. 1 and 2 has a damper case 11
A piston 12 is provided inside the damper case 11, and two fluid chambers 1 partitioned by the piston L2 are provided inside the damper case 11.
3A and 13B, and an actuating shaft 15 fixed to the piston 12 extends inwardly and outwardly at both ends of the damper case 11.

Note that 17 is a sealing member.

Thus, the fluid damper 10 has two fluid chambers 1 between the inner peripheral surface of the damper case 11 and the outer peripheral surface of the piston 12.
3A and 13B are provided, and a pair of ring-shaped electrodes 22 and 23 are provided on the entire inner circumferential surface of the damper case 11 and the outer circumferential surface of the piston 12, respectively, facing each other through the gap 21. , and the two fluid chambers 13A,
13B is loaded with an electrorheological fluid having a Winslow effect.

Note that the electrodes 22 and 23 are provided with electrical insulators 24 on the damper case 11 and the bodies 11A and 12A of the piston 12, respectively.
．． 25.

Further, a voltage source V is connected between the electrode 22 and the electrode 23. The voltage source V can be taken in from the extending end of the actuating shaft L5 located outside the damper case 11. Also, the voltage source V
may be built into the damper case 11, the piston 12, or the actuating shaft 15.

Next, the operation of the above embodiment will be explained.

In the fluid damper 10, each of the inner circumferential surface of the damper case 11 and the outer circumferential surface of the piston 12 is provided with a gap 21 formed therebetween that communicates the two fluid chambers 13A and 13B. Since a pair of electrodes 22.23 are provided, and the two fluid chambers 13A and 13B formed inside the damper case 11 are filled with an electrorheological fluid having a Winslow effect, there is a gap between the two electrodes 22.23. When a voltage is applied, if the electrorheological fluid flows through the gap 21 from the fluid chamber 13A to the fluid chamber 13B, an electric field is formed that is perpendicular to the flow of the electrorheological fluid in the opposite direction, and both electrodes 22, 23 This increases the viscosity of the electrorheological fluid sandwiched between the two. Therefore, the viscosity of the fluid moving from one fluid chamber through the gap 21 to the other fluid chamber is controlled, and as a result, the throttling resistance of the fluid in the gap 21 is adjusted, and the vibration damping characteristics of the fluid damper 10 are adjusted. Adjustable. That is, by appropriately controlling the voltage applied between both electrodes 22 and 23 according to the position, speed, moving direction, etc. of the piston 12 with respect to the damper case 11, the vibration damping characteristics of the fluid damper 10 can be adjusted extremely easily. can.

Further, in the above embodiment, the fluid can pass through the gap 21 between the inner circumferential surface of the damper case 11 and the outer circumferential surface of the piston 12 without sealing it with a sealing member attached to the outer circumferential surface of the piston 12. It functions as a flow path. Therefore, the frictional force generated between the conventional seal member and the inner circumferential surface of the damper case 11 does not act as resistance to the displacement of the piston 12, and the piston 12 can operate smoothly and quickly. Moreover, the gap 21 between the inner circumferential surface of the damper case 11 and the outer circumferential surface of the piston 12, which is not provided with a sealing member, is actively utilized as a control element.

Further, the electrodes 22 and 23 of the above embodiment are arranged in the damper case 1.
1 and the outer circumferential surface of the piston 12 over a wide range. Therefore, even if only a relatively low voltage is applied between both electrodes 22.23, both electrodes 22.23
This results in a viscosity change being applied to a large amount of fluid caught in a wide range between the two, and as a result, the vibration damping characteristics of the fluid damper 10 can be effectively adjusted.

Therefore, according to the above embodiment, the vibration damping characteristics of the fluid damper 10 can be adjusted extremely easily, and the piston 12 can be operated smoothly and quickly with respect to the damper case 11, which is optimal for the vibration system. It is possible to provide a vibration damping effect.

Note that the fluid damper IO may be provided with an orifice 26 inside the piston 12 that communicates the fluid chamber 13A and the fluid chamber 13B.

The fluid damper 30 in FIGS. 3 and 4 is similar to the fluid damper 10 described above.
The following configuration is added to the above configuration. That is, the fluid damper 30 has two fluid chambers 13A and 13B in the piston 12 in addition to the above-mentioned fluid tank/
A square hole-shaped communicating path 14 is provided, and a pair of electrodes 32 and 33 are provided on each of the opposing inner surfaces with the communicating path 14 interposed therebetween, with an electrical insulator 31 interposed therebetween.

Therefore, according to this fluid damper 30, the viscosity of the fluid passing through the gap 21 similar to that in the fluid damper 10 is controlled, and at the same time, the viscosity of the fluid passing through the communication passage 14 of the piston 12 is controlled. This means that the vibration damping characteristics of the can be adjusted.

FIG. 5 shows an electrode 22 provided on the inner peripheral surface of the damper case 11.
The electrode 23 provided on the outer peripheral surface of the piston 12 is shaped like an external gear.

FIG. 6 shows an electrode 22 provided on the inner peripheral surface of the damper case 11.
and electrodes 23 provided on the outer peripheral surface of the piston 12 are arranged at a plurality of positions intermittently in the circumferential direction.

Further, in implementing the present invention, the electrodes provided on the inner peripheral surface of the damper case may be provided at a plurality of positions intermittently in the axial direction.

Furthermore, in carrying out the present invention, the electrodes provided on the outer circumferential surface of the piston are not provided over the entire area of the piston in the axial direction, but only on one end surface side of the piston, only on both end surface sides, and only on the approximately central portion in the axial direction. Alternatively, they may be provided at a plurality of positions intermittently in the axial direction.

[Effects of the Invention] As described above, according to the present invention, the vibration damping characteristics of a fluid damper can be adjusted extremely easily.

Moreover, the piston can be operated smoothly and quickly with respect to the damper case, and an optimal vibration damping effect can be imparted to the vibration system.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a longitudinal cross-sectional view showing one embodiment of the present invention, Fig. 2 is a cross-sectional view of Fig. 1, and Fig. 3 is a longitudinal cross-sectional view showing another embodiment of the present invention. 4 is a cross-sectional view of FIG. 3, FIG. 5 is a sectional view showing a modification of the electrode installation state, and FIG. 6 is a sectional view showing another modification of the electrode installation state. 1O530... Fluid damper, 11... Damper case, 12... Piston, 13A, 13B... Fluid chamber, 15... Operating shaft, 21... Gap, 22.23... Electrode. Agent Patent Attorney Osamu Shiokawa Figure 1 Figure 2 Figure 6

Claims (1)

[Claims] (1) A fluid damper in which a piston is provided in a damper case, two fluid chambers are formed within the damper case partitioned by the piston, and an operating shaft fixed to the piston extends inside and outside the damper case, A gap is provided between the inner circumferential surface of the damper case and the outer circumferential surface of the piston to communicate the two fluid chambers, and electrodes are provided on each of the inner circumferential surface of the damper case and the outer circumferential surface of the piston, facing each other through the gap. A fluid damper characterized in that the two fluid chambers are filled with an electrorheological fluid having a Winslow effect.