JPH03265720A - Fluid type torque transmission device - Google Patents

Abstract

PURPOSE:To restrict the drop in slide performance between a shaft-like body of rotation and a cylindrical body of rotation by adding a liquid, which has a larger specific gravity than dispersed phase grains and dispersion mediums and which is not compatible with the dispersion mediums, to an electroviscous fluid. CONSTITUTION:A torque transmission unit 14 is provided with a cylindrical body 16 of rotation and a shaft-like body 18 of rotation, and a space between both the bodies 16, 18 of rotation is filled with an electroviscous fluid whose viscosity is changed in response to the strength of an electric field in use. Further, a liquid whose specific gravity is larger than that of dispersed phase grains and dispersion mediums and which is not compatible with the dispersion mediums, is added to the electroviscous fluid. Sometimes, the electroviscous fluid in which specific gravity of the dispersion mediums is larger than that of the dispersed phase grains is used. As a result, even when centrifugal force acts on the electroviscous fluid, the liquid 42 with greater specific gravity enters a space 40 between an inside electrode 32 and the circular groove 38 of an outside insulating ring 28 to remove the dispersed phase grains 44 from the space 40, and thereby the drop in slide performance between the cylindrical body 16 of rotation and the shaft-like body 18 of rotation can be restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a fluid torque transmission device using an electrorheological fluid as a torque transmission medium.

(Background technology) When a viscous fluid is interposed between opposing discs and one of them is rotated, the other disc is also rotated based on the shear stress of the viscous fluid located between the discs. . Hydrodynamic torque transmission devices utilize this principle to transmit torque, and generally, as disclosed in Japanese Patent Application Laid-Open No. 63-34331, the outer periphery of a ring-shaped rotating body is A plurality of circular brim-shaped inner disk members fixed to the surface and a plurality of circular brim-shaped outer disk members fixed to the inner peripheral surface of the cylindrical rotating body are arranged in a space filled with viscous fluid. The structure is such that they are arranged alternately with a predetermined gap in the axial direction so as to be relatively rotatable.

By the way, in this type of fluid torque transmission device,
Newtonian fluid is generally used as the viscous fluid that transmits torque, but in recent years, as such viscous fluid,
It has been proposed to employ an electrorheological fluid whose viscosity changes substantially (apparently) depending on the magnitude of the applied electric field.

Therefore, this fluid type torque transmission device using an electrorheological fluid uses an electrorheological fluid instead of Newtonian fluid in the conventional fluid type torque transmission device as described above, but the inner disc member and the outer disc member are different from each other. This can be achieved by using electrodes with different polarities from the plate member, but in a fluid torque transmission device using this type of electrorheological fluid, the relative It is required to accurately maintain the distance between the facing electrodes. This is because in a torque transmission device using an electrorheological fluid, the torque transmission characteristics vary greatly due to variations in the distance between electrodes, and if opposing electrodes come into contact, there is a risk of causing an electrical short circuit phenomenon.

Therefore, the applicants of the present application first filed the patent application No. 1-12076.
In No. 7, in the above-mentioned torque transmission device using an electrorheological fluid, an inner insulating ring is interposed between the inner circumferential edges of the inner electrodes, an outer insulating ring is arranged between the outer circumferential edges of the outer electrodes, and the The inner insulating ring and the outer insulating ring each have a circumferential annular groove, so that the inner circumferential edge of the outer electrode is guided in the circumferential direction by the annular groove of the inner insulating ring, while the outer circumferential edge of the inner electrode is guided in the outer insulating ring. We proposed that the ring be guided in the circumferential direction by an annular groove. In this way, both the inner and outer peripheral edges of the inner and outer electrodes are constrained in the axial direction, so that the distance between the opposing electrodes is maintained at a constant distance with high precision. Moreover, it is possible to effectively prevent short-circuit accidents caused by contact between opposing electrodes.

However, when the inner and outer peripheries of the inner and outer electrodes are guided in the circumferential direction by insulating rings, the shaft-like rotating body and the cylindrical rotating body gradually change over time after the rotation operation starts. The sliding performance between the rotary shaft and the cylindrical rotor gradually deteriorates, and eventually the relative rotational performance between the shaft-shaped rotary body and the cylindrical rotary body is significantly impaired, and there is a possibility that control of the transmitted torque becomes impossible.

The reason for this is thought to be as follows. That is, electrorheological fluids generally consist of water-absorbing fine particles such as silica gel, starch, cellulose, metal salts of acid group-containing polymers, or organic semiconductor fine particles such as boriacene quinone dispersed in a highly electrically insulating oily substance. However, in these ordinary electrorheological fluids, the specific gravity of the dispersed phase particles is greater than that of the dispersion medium, so when used in a torque transmission device,
A type of centrifugal separation effect acts on the electrorheological fluid, and more dispersed phase particles with a larger specific gravity are distributed on the outer circumferential side. Here, in a torque transmission device in which the outer peripheral edge of the inner electrode is guided in the circumferential direction by an outer insulating ring, the gap between the inner electrode and the annular groove of the outer insulating ring is extremely small. If a large number of dispersed phase particles separated by centrifugation enter the gap due to centrifugal force, the sliding resistance between the inner electrode and the outer insulating ring will be significantly increased by the dispersed phase particles that have entered the gap. . As a result, it is thought that the sliding performance between the shaft-shaped rotating body and the cylindrical rotating body is significantly reduced.

(Problems to be solved) The present invention has been made in view of the above circumstances, and the problems to be solved are as follows:
A hydraulic torque transmission device of a type configured such that an outer circumferential edge of an inner electrode and an inner circumferential edge of an outer electrode are guided in the circumferential direction by an outer insulating ring and an inner insulating ring, respectively. It is an object of the present invention to provide a fluid type torque transmission device capable of stably controlling torque transmission by satisfactorily suppressing deterioration in sliding performance with a shaped rotating body.

(Solution Means) In order to solve this problem, the first invention of the present invention includes a plurality of circular flange-shaped inner electrodes fixed to the outer peripheral surface of the shaft-like rotating body, as described above; A plurality of circular flange-shaped outer electrodes fixed to the inner circumferential surface of a cylindrical rotating body are arranged alternately in a space filled with electrorheological fluid so that they can rotate relative to each other at a predetermined distance in the axial direction. At the same time, a predetermined voltage can be applied between the inner electrode and the outer electrode, and an outer insulating ring is interposed between the outer peripheral edge of the outer electrode. The outer circumferential edge of the inner electrode is guided in the circumferential direction by the annular groove, and an inner insulating ring is interposed between the inner circumferential edges of the inner electrode, and the annular groove formed in the inner insulating ring guides the outer electrode. In a hydrodynamic torque transmission device of the type in which the inner peripheral edge of the electrorheological fluid is guided in the circumferential direction, the electrorheological fluid contains dispersed particles having a specific gravity larger than that of the dispersed phase particles and the dispersion medium constituting the electrorheological fluid. It was decided to add a liquid that is incompatible with the medium.

Further, in a second aspect of the present invention, in a fluid torque transmission device of the same type as described above, an electrorheological fluid in which the specific gravity of the dispersion medium is larger than the specific gravity of the dispersed phase particles is used as the electrorheological fluid. That's what I did.

(Operation/Effect) In the torque transmission device according to the first aspect of the present invention, in the electrorheological fluid, dispersed phase particles of the electrorheological fluid and a liquid having a higher specific gravity than the dispersion medium and which is incompatible with the dispersion medium are added. is added, so when the electrorheological fluid is subjected to centrifugal separation, more of the added liquid will be unevenly distributed in the outer circumference. Therefore, the added liquid enters the gap between the outer circumferential edge of the inner electrode and the annular groove of the outer insulating ring, and the dispersed phase particles are removed. This effectively prevents the sliding resistance between the electrode and the outer insulating ring from being increased by the dispersed phase particles. In other words, deterioration in the sliding performance between the shaft-like rotating body and the cylindrical rotating body is effectively suppressed, and torque transmission can be controlled stably.

Further, in the torque transmission device according to the second invention, since an electrorheological fluid is used in which the specific gravity of the dispersion medium is larger than the specific gravity of the dispersed phase particles, the gap between the outer peripheral edge of the inner electrode and the annular groove of the outer insulating ring is A dispersion medium with a large specific gravity enters the gap due to centrifugal force, and therefore, similarly to the first invention, a decrease in the sliding performance between the shaft-like rotating body and the cylindrical rotating body is well suppressed. The Rukoto.

(Example) Hereinafter, in order to clarify the present invention more specifically,
The embodiment will be described in detail based on the drawings.

First, in FIG. 1, reference numerals 1012 are a human-powered shaft to which rotational torque is manually applied from a predetermined rotational torque source, and a human-powered shaft that outputs the torque transmitted from the human-powered shaft 10, respectively.
They are the second output shafts, and are coaxially connected to each other via the torque transmission section 14.

The torque transmitting unit 14 includes a cylindrical rotary body 16 having a bottomed cylindrical shape and concentrically connected to the end face of the output shaft 12 so as to be non-rotatable.
and an annular rotating body 18 that is coaxially connected to the end face of the input shaft 10 so as to be unable to rotate relative to the input shaft 10. A closing member 20 disposed at the opening of the rotating body 16 fluid-tightly closes the opening of the rotating body 16 in a manner that allows relative rotation of the two rotating bodies 16°18. The space between the rotating bodies 16 and 18 that is closed by the closing member 20 is filled with an electrorheological fluid whose viscosity substantially changes depending on the intensity of the applied electric field. Note that 21 is a sealing material.

Here, both the cylindrical rotating body 16 and the shaft-shaped rotating body 18 are made of metal materials, but the closing member 20 is made of a non-conductive material such as a resin material.

Further, the bottom wall portion of the cylindrical rotating body 16 and the tip end surface of the annular rotating body 18 are separated by a spacer 22 made of a non-conductive material and arranged in a form that allows relative rotation therebetween. Here, the cylindrical rotating body 16 and the shaft-shaped rotating body 18 are electrically separated from each other by this.

By the way, on the inner peripheral surface of the cylindrical rotating body 16, there is a spline 2.
4 is formed, and an outer electrode 26 which is a circular metal plate and an annular outer insulating ring 28 made of an insulating material are alternately fitted to this spline 24 and fixedly arranged. There is. On the other hand, splines 30 are also formed on the outer peripheral surface of the shaft-like rotor 18 inserted into the cylindrical rotor 16, and the splines 30 are alternately fitted to
A circular brim-shaped inner electrode 32 similar to the outer electrode 26 and an annular inner insulating ring 34 similar to the outer insulating ring 28
are fixedly arranged. As a result, the outer electrodes 26 and the inner electrodes 32 are alternately arranged in the electrorheological fluid filled space with a certain gap between them in the axial direction so as to be relatively rotatable.

Note that the inner electrode 32 on the most extreme side of the shaft-shaped rotating body 18 is configured integrally with the ring-shaped rotating body 18 here.

Here, annular grooves 36 and 38 extending in the circumferential direction are formed in the outer circumferential surface of the inner insulating ring 34 and the inner circumferential surface of the outer insulating ring 28, respectively, and the inner circumferential edge of the outer 1 2 side electrode 26 and The outer peripheral edges of the inner electrodes 32 are slidably inserted in the respective annular grooves 36, 38 in the circumferential direction. As a result, when the electrodes 26 and 32 rotate relative to each other, the outer electrode 2
The inner peripheral edge of the inner electrode 32 is guided in the circumferential direction by the annular groove 36 of the inner insulating ring 34.
The outer peripheral edge of the outer insulating ring 28 is guided in the circumferential direction by an annular groove 38 of the outer insulating ring 28.

In this example, in a fluid torque transmission device having such a structure, a normal electrorheological fluid is used as the electrorheological fluid, for example, an oily substance with high electrical insulation is used as a dispersion medium, while dispersed phase particles Water-absorbing fine particles such as starch, cellulose, metal salts of acid group-containing polymers,
Alternatively, in an electrorheological fluid containing organic semiconductor fine particles such as polyacene quinone, a liquid having a specific gravity higher than that of the dispersion medium or dispersed phase particles and which is incompatible with the dispersion medium, for example, a liquid having a specific gravity of 1, Liquids such as perfluoropolyether (product name of Fluorinert IAM) with a specific gravity of about 7 to 2.0, fluorinated silicone oil with a specific gravity of about 1.2 to 1.3, or fluorophosphazene oil with a specific gravity of about 1.8 are used. , an electrorheological fluid added in a predetermined amount is employed.

In the hydrodynamic torque transmission device having such a configuration, the outer electrode 26 is passed through the cylindrical rotating body 16 and the axial rotating body 18.
When a voltage is applied between the inner electrodes 32 and 32, the inner electrodes 2
Since the viscosity of the electrorheological fluid located at 6.32 changes depending on the voltage, the voltage is transmitted from the input shaft 10 side to the output shaft 12 side by controlling the voltage applied between these electrodes 26.32. torque can be controlled.

In the torque transmission device of this example, as described above, the outer peripheral edge of the inner electrode 32 and the inner peripheral edge of the outer electrode 26 are shaped like the annular groove 38 of the outer insulating ring 28 and the annular groove of the inner insulating ring 34, respectively. Since each electrode 26.32 is guided circumferentially in the groove 36 and the free end of each electrode 26.32 is constrained in the axial direction, the distance between the opposing electrodes 26.32 is accurate. It is well maintained, and the occurrence of control errors in torque transmission characteristics due to fluctuations in the distance between these electrodes 26, 32 is well suppressed, and the occurrence of short circuit accidents due to contact between these electrodes 26, 32 is well suppressed. is prevented.

Therefore, in the torque transmission device of this example as well, a kind of centrifugal separation effect acts on the electrorheological fluid as in the conventional torque transmission device of this type, but in this example, as described above, , because a liquid with a higher specific gravity than the dispersion medium and dispersed phase particles of the electrorheological fluid is added to the electrorheological fluid, and which does not dissolve in the dispersion medium, this liquid with high specific gravity is affected by centrifugal force. As a result, more of it is unevenly distributed in the outer peripheral portion.

Therefore, as shown in FIG. 2, the liquid 42 with a high specific gravity enters the gap 40 between the inner electrode 32 and the annular groove 38 of the outer insulating ring 28.
The dispersed phase particles 44 will be excluded from the gap 40, and therefore the dispersed phase particles 44 that have entered the gap 40 will be excluded from the gap 40.
This effectively prevents the sliding resistance between the inner electrode 32 and the outer insulating ring 28 from increasing. In other words, the sliding performance between the cylindrical rotating body 16 and the shaft-shaped rotating body 18, and furthermore the sliding performance between the input shaft 10 and the output shaft 12, is effectively prevented from being deteriorated. In addition, in FIG. 2, 46 indicates a dispersion medium.

Incidentally, such an effect of preventing a decrease in slip performance can also be obtained by employing an electrorheological fluid in which the dispersion medium 46 has a higher specific gravity than the dispersed phase particles 44.

If the specific gravity of the electrorheological fluid dispersion medium 46 is made larger than that of the dispersed phase particles 44, the gap 401 between the inner electrode 32 and the annular groove 38 of the outer insulating ring 28 becomes larger as shown in FIG. Because the dispersion medium 4G with a large specific gravity enters through phase separation due to centrifugal separation, the gap 40
This effectively prevents the dispersed phase particles 44 from entering into the inner electrode 32 and the outer insulating ring 28 from increasing the sliding resistance.

In addition, in the dispersion medium 46 of such an electrorheological fluid, the dispersed phase particles 44 are water-absorbing fine particles such as starch, metal salts of cellulose acid group-containing polymers, organic semiconductor fine particles such as polyacene quinone, etc. In some cases,
Perfluoropolyether and fluorinated silicone oil,
Alternatively, fluorophosphazene oil or the like can be suitably employed.

Although the embodiments of the present invention have been described in detail above, these are literal illustrations, and the present invention is not limited to these specific examples, and various modifications and changes may be made without departing from the spirit thereof. Of course, the present invention can be implemented with modifications, improvements, etc.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing an example of a fluid torque transmission device according to the present invention, and FIG. 2 illustrates a state of phase separation due to centrifugal separation of electrorheological fluid in the device of FIG. 1. FIG. 3 is a diagram corresponding to FIG. 2 of another embodiment. 14: Torque transmission part 16: Cylindrical rotating body Annular rotating body Outer insulating ring Inner insulating ring Gap Dispersed phase particles 26: Outer electrode 32: Inner electrode 36. 38: Annular groove 42: Liquid 46: Dispersion medium

Claims (2)

[Claims] (1) A plurality of inner electrodes in the shape of a circular brim fixed on the outer circumferential surface of the axial rotating body and a plurality of outer electrodes in the shape of a circular brim fixed on the inner circumferential surface of the cylindrical rotating body are connected to each other using an electrorheological fluid. The inner electrodes and the outer electrodes are alternately arranged so as to be relatively rotatable at a predetermined distance from each other in the axial direction in the filling space, and a predetermined voltage can be applied between the inner electrode and the outer electrode, and An outer insulating ring is interposed between the outer peripheral edge of the outer electrode,
An annular groove formed in the outer insulating ring guides the outer peripheral edge of the inner electrode in the circumferential direction, and an inner insulating ring is interposed between the inner peripheral edges of the inner electrode. In a fluid type torque transmission device in which the inner peripheral edge of the outer electrode is circumferentially guided in an annular groove, dispersed phase particles and a dispersion medium constituting the electrorheological fluid are contained in the electrorheological fluid. A fluid torque transmission device characterized in that a liquid having a high specific gravity and incompatible with the dispersion medium is added. (2) A plurality of inner electrodes in the shape of a circular brim fixed on the outer circumferential surface of the axial rotating body and a plurality of outer electrodes in the shape of a circular brim fixed on the inner circumferential surface of the cylindrical rotating body are connected to each other by electrorheological fluid. The inner electrodes and the outer electrodes are alternately arranged so as to be relatively rotatable at a predetermined distance from each other in the axial direction in the filling space, and a predetermined voltage can be applied between the inner electrode and the outer electrode, and An outer insulating ring is interposed between the outer peripheral edge of the outer electrode,
An annular groove formed in the outer insulating ring guides the outer peripheral edge of the inner electrode in the circumferential direction, and an inner insulating ring is interposed between the inner peripheral edges of the inner electrode. In a fluid torque transmission device of a type in which the inner circumferential edge of the outer electrode is guided in the circumferential direction in an annular groove, the electrorheological fluid is an electrorheological fluid in which the specific gravity of the dispersion medium is greater than the specific gravity of the dispersed phase particles. A fluid torque transmission device characterized by using fluid.