JP2001095267A - Electrostatic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the dimension of an apparatus in the direction of a rotating shaft, as well as loss torque in a rotary electrostatic actuator. SOLUTION: This electrostatic actuator is provided with a rotating shaft 11, rotatably journalled to bearings 3A, 3B, a rotor 12 which is formed so that a plurality of electric poles 16a, 16b are disposed radially on an insulating layer 15 fixed to the rotating shaft 11, and in which the electric poles are connected at intervals in a prescribed number thereof to form multiple phases, a stator 22 which is formed so that a plurality of electric poles 26a, 26b, 26c are disposed on the insulating layer 25 to face the rotor 12, and in which the electric poles are connected at intervals in a prescribed number thereof to form multiple phases, and a feeding means 30 for applying voltage to the electric poles 16a, 16b, 26a-26c of the rotor 12 and the stator 22 for feeding current to the poles 16a, 16b of the rotor 12 via the bearings 3A, 3B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding device such as a sun visor, a moon roof, a sun roof and a rear window of an automobile, a light-shielding device of a railway, an aircraft, a ship or the like, or a driving source of a paper feeder of a copying machine. The present invention relates to an electrostatic actuator to be used.

[0002]

2. Description of the Related Art Conventionally, a rotating shaft rotatably supported by a bearing, a rotor having a plurality of electrodes radially provided on an insulating layer fixed to the rotating shaft, and a rotor arranged opposite to the rotor. There is known a rotary electrostatic actuator including a stator having a plurality of electrodes provided radially on an insulating layer. Electrodes are connected every other one of the rotor and the stator to form a plurality of phases, and a voltage having a fixed polarity is applied to each phase. On the other hand, electrodes are connected every predetermined number to form a plurality of phases, and a voltage whose polarity is periodically switched is applied to each phase. As a result, the rotor is rotationally driven by the electrostatic attraction and repulsion generated between the electrodes of the rotor and the stator.

[0003] As a method of supplying power to the electrodes of the rotor, there is a wired power supply method in which a power supply side and an electrode side are connected by an electric wire. However, in the case of this method, the rotor cannot rotate beyond a certain number of rotations.

As a power supply method in which the number of revolutions of the rotor is not limited, there is a method in which power is supplied by a brush connected to the power supply side and a slip ring connected to the electrode side of the rotor and rotating integrally with the rotor. is there. The power supply system using the brush and the slip ring is roughly classified into two types.
The first method is a method (radial contact type) in which a plurality of slip rings are stacked in the axial direction of a rotating shaft and a brush is brought into contact with each slip ring from a radial direction of the rotating shaft. The second method is a method (thrust direction contact type) in which a plurality of slip rings are provided concentrically and a brush is brought into contact with each slip ring from the axial direction of the rotation shaft.

[0005]

However, in the case of the above-mentioned radial contact type power supply system, since the slip rings are provided so as to be stacked in the axial direction of the rotary shaft as described above, the axial direction of the rotary shaft or the rotor The size of the device in the thickness direction increases. Further, in the case of the above-mentioned thrust direction contact type power supply system, since the outermost one of the concentrically provided slip rings is farther from the rotating shaft, a loss torque due to sliding resistance between the brush and the slip ring is reduced. large. Furthermore, in the power supply system using a brush and a slip ring, the number of components required for supplying power to the electrodes of the rotor increases.

Accordingly, an object of the present invention is to reduce the size of the device in the axial direction of the rotating shaft, reduce the torque loss, and reduce the number of components required for power supply in a rotary electrostatic actuator.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a bearing, a rotating shaft rotatably supported by the bearing, and a plurality of electrodes on an insulating layer fixed to the rotating shaft. A rotor in which a plurality of phases are formed by connecting electrodes at predetermined intervals to form a plurality of phases, and a plurality of electrodes are radially provided on an insulating layer disposed opposite to the rotor, and The electrode is connected to the stator to form a plurality of phases, and the voltage is applied to the electrodes of each phase of either the rotor or the stator while the polarity is fixed, and the polarity is applied to the electrodes of the other phase. Power supply means for applying a voltage in a fixed manner, and an electrostatic actuator for rotating and driving the rotor by electrostatic attraction and repulsion acting between the rotor and the electrodes of the stator; Electrostatic actuator characterized by feeding power to rotor electrodes Data.

In the electrostatic actuator of the present invention, since the rotor supplies power to the electrodes of the rotor via the bearing of the fixed rotating shaft, a slip ring and a brush for supplying power to the electrodes of the rotor are provided. No need. Therefore, it is possible to reduce the number of components for power supply, reduce the torque loss, and reduce the size of the device in the axial direction of the rotating shaft.

The bearing is a rolling bearing having an inner ring, a plurality of spheres, and an outer ring each made of a conductive material. The bearing is provided on an insulator fixed to the rotating shaft, and the rolling is provided on the insulator. An inner ring of the bearing is fixed, and a conductor to which the electrode of the rotor is connected, and a power supply line connected to the outer ring of the bearing, and the rotor passes through the rolling bearing and the conductor from the power supply line. It is preferable to supply power to the electrodes.

In this case, the plurality of spheres serve as contact points for conducting between the inner ring and the outer ring of the rolling bearing, and one of the spheres reliably connects the inner ring and the outer ring. Is done.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention shown in the drawings will be described in detail. (First Embodiment) An electrostatic actuator according to a first embodiment of the present invention shown in FIG. 1 includes a short-cylindrical housing 1 with both ends closed, and is provided at the center of the upper end wall and the lower end wall of the housing 1. Rolling bearings 3A and 3B are fixed to the openings via mounting members 2A and 2B, respectively.

The above-mentioned rolling bearings 3A, 3B are provided with inner rings 3a,
This is a known structure including a plurality of balls (spheres) 3b and an outer ring 3c. The inner ring 3a, the ball 3b, and the outer ring 3c are all made of a conductive metal material. Silver paste between the inner ring 3a and the outer ring 3c;
A conductive lubricant such as mercury is contained. However, when the ball 3b can roll smoothly, it is not necessary to use a lubricant.

In the figure, a connector 6a is mounted on a mounting member 2A holding a lower rolling bearing 3A, and one end of an A-phase power supply line 8A is electrically connected to an outer ring 3c of the rolling bearing 3A by the connector 6a. Connected. The other end of the A-phase power supply line 8 </ b> A is connected to a connector 9 attached to the outside of the housing 1. Similarly,
In the drawing, a connector 6b is attached to an attachment member 2B holding the upper rolling bearing 3B, and the connector 6b is connected to one end of a B-phase power supply line 8B to the outer ring 3c of the rolling bearing 3B. This B-phase feed line 8B
Is connected to the connector 9.

A rotating shaft 11 made of metal is rotatably supported by the rolling bearings 3A and 3B, and one end of the rotating shaft 11 projects from the housing 1 to the outside. A disk-shaped rotor 12 is fixed to the rotation shaft 11, and the rotation shaft 11 passes through the center of the rotor 12. Rotary axis 1
An insulator 13A, 1 made of a non-conductive resin is
3B is provided. In addition, each insulator 13A, 13B
A conductor 14A made of a conductive metal,
14B are formed. Since the insulators 13A and 13B are fixed to the rotating shaft 11 and the conductors 14A and 14B are fixed to the insulators 13A and 13B, the insulators 13A and 13B and the conductors 14A and 14B rotate. It rotates integrally with the shaft 11. Each conductor 14A, 14B has
The inner race 3a of each of the rolling bearings 3A and 3B is fixed. Each conductor 14A, 14B and inner ring 3a are electrically connected. Further, as described later, each conductor 14A,
14B is connected to the electrodes 16a and 16b of the rotor 12. The conductors 14A and 14B and the rotating shaft 11 are insulated by insulators 13A and 13B, respectively. Also,
The conductors 14A and 14B are separated from each other by the insulating layer 15 of the rotor 12.
Are insulated from each other.

As shown in FIG. 2, the rotor 12 has a disk-shaped insulating layer 15 made of a dielectric such as polyethylene terephthalate (PET).

On one surface (lower surface in FIG. 1) 15a of the insulating layer 15 of the rotor 12, a plurality of elongated rectangular electrodes 16a, 1 made of a conductive metal are provided.
.. 16a, 16b... Are provided radially.
These electrodes 16a, 16b are provided on one surface 15a of the insulating layer 15 for every other electrode 16a, 16b.
Ring-shaped power supply portions 17A formed on the center side and the outer peripheral side of the
17B, and is connected to the power supply unit 17 on the center side.
The electrodes 16a, 16a,... Connected to A constitute the A phase,
Electrodes 16b and 16 connected to power supply section 17B on the outer peripheral edge side
... constitute the B phase.

The A-phase power supply section 17A is electrically connected to a conductor 14A formed below the rotor 12 in the figure. On the other hand, the B-phase power supply portion 17B is electrically connected to the rotor 12 via a through hole 18 to a conductor 14B formed on the upper side in the drawing.

In the present embodiment, as shown in FIG. 4, the dimension (width) d1 of the A-phase electrode 16a and the B-phase electrode 16b in the rotational direction of the moving element 3 is the same. The distance P1 between the adjacent electrodes 16a and 16b is constant, and the width d
It is set to twice of 1.

A stator 22 is fixed to the upper surface of the mounting member 2A located below the rotor 12 in the figure so as to face the rotor 12 with a gap therebetween.

As shown in FIG. 3, the stator 22 is provided with a disk-shaped insulating layer 25 made of a dielectric material such as PET and having a circular hole 22a formed in the center.
The insulator 13A and the conductor 13B are inserted with a sufficient gap.

One surface of the insulating layer 25 of the stator 22 (FIG. 1)
A plurality of elongated rectangular electrodes 26a, 26b, 26 made of a conductive metal
c ... 26a, 26b, 26c ... are provided radially.

These electrodes 26a to 26c are connected to each other every other electrode 26a to 26c. The electrodes 26a, 26a,.
Is connected to an annular power supply portion 27A formed in the vicinity of the circular hole 25a on one surface 25b, and constitutes a U-phase. Also, the electrodes 26b are formed with an annular power supply portion 27B formed near the outer peripheral edge of the one surface 25b of the insulating layer 25.
To form a V-phase. Further, the electrode 26
, 26c... are formed on the insulating layer 2 through the through holes 28a.
5 is electrically connected to an annular power supply portion (not shown) formed on the other surface (the lower surface in FIG. 1) 25c to form a W phase.

A connector 6c is connected to the other surface 25c of the insulating layer 15, and the U-phase power supply 27A,
V-phase power supply 27B is connected to through-holes 28b, 2
8c, it is electrically connected to one end of the U-phase power supply line 8C and one end of the V-phase power supply line 8D. Also, the W-phase power supply unit (not shown) is connected to the W-phase power supply line 8E via the connector 6c.
Is electrically connected to one end. From these U phases to W
The other ends of the phase feeders 8C to 8E are connected to the connector 9.

The U-phase, V-phase and W-phase electrodes 26a,
The dimensions (width) d2 of the electrodes 26b and 26c in the rotation direction of the rotor 12 are the same, and the width d2 is
Is equal to the width d1 of the electrodes 16a and 16b. The interval P2 between the adjacent electrodes 26a to 26c is constant, and the width d is
Equal to 2.

The connector 9 is connected to a power supply device (power supply means) 30 schematically shown in FIG. The power supply device 30 includes a power supply, a switching element, a control circuit for the switching element, and the like (none of them are shown).
2 outputs a high voltage to the power supply lines 8A to 8E during the rotational drive.

In this embodiment, as shown in FIG. 5, the power supply device 30 outputs a positive high voltage with a fixed polarity to the A-phase power supply line 8A, and outputs a negative high voltage to the B-phase power supply line 8B. Outputs high voltage with fixed polarity. Also, the U-phase to W-phase power supply line 8
For C to 8E, a high DC voltage (alternating voltage) whose polarity is switched periodically is output.

The positive high voltage output to the A-phase power supply line 8A is applied to the outer ring 3c, the ball 3b and the inner ring 3 of the rolling bearing 3A.
a through the conductor 14A and the through hole 18, from the power supply portion 17A to each of the A-phase electrodes 16a of the rotor 12, 16a,.
Is applied to Similarly, the negative high voltage output to the B-phase power supply line 8B is transmitted from the outer ring 3c, the ball 3b and the inner ring 3a of the rolling bearing 3B via the conductor 14B to the power supply unit 17B to the respective B-phase electrodes 16b of the rotor 12. , 16b...

The high voltage output to the U-phase and V-phase power supply lines 8C and 8D passes through the U-phase and V-phase power supply units 27A and 27B via the through holes 28b and 28c, respectively.
, 26b, 26b,... Are applied to the phase electrodes 26a, 26a,. Also, the high voltage output to the W-phase power supply line 8E is supplied from the W-phase power supply unit (not shown) to the W-phase electrodes 26c, 26c,.
Is applied to

When a high voltage is applied to the electrodes 16a and 16b and the electrodes 26a to 26c as described above, the electrodes 16a and 16b of the rotor 12 and the electrode 26a of the stator 22
To 26c, an electrostatic attraction force and a repulsion force act, and the rotor 12 rotates with respect to the stator 22. The rotating shaft 11 supported by the rolling bearings 3A and 3B is the rotor 1
Rotate with 2.

In the electrostatic actuator of the present embodiment, since the high voltage is applied to the electrodes 16a and 16b of the rotor 12 via the bearings 3A and 3B that support the rotating shaft 11 as described above, the brush and the There is no need to provide a slip ring. Therefore, the dimension in the axial direction of the rotating shaft 11 or the thickness direction of the rotor 12 can be reduced as compared with the case where a radial contact type brush and a slip ring are used. Further, the sliding resistance is reduced as compared with the case where a thrust direction contact type brush and slip ring are used, so that the torque loss can be reduced. Furthermore, since the bearings 3A and 3B that support the rotating shaft 11 also function as conventional brushes and slip rings, the power supply structure is simple and the number of components required for power supply can be reduced. Furthermore, since the plurality of balls 3b serve as contact points and the outer ring 3c and the inner ring 3a of each of the rolling bearings 3A and 3B are electrically connected, conduction between the outer ring 3c and the inner ring 3a is surely achieved by any one of the balls 3b. Secured. Therefore, poor conduction is unlikely to occur between the outer ring 3c and the inner ring 3a, and a high voltage is reliably supplied to the electrodes 16a and 16b of the rotor 12. Furthermore, in this embodiment, since the bearings 3A and 3B are provided on both sides of the rotor 12, the rotating shaft 11
Is stably supported by the bearings 3A and 3B.

The waveform of the alternating voltage output from the power supply device 30 is not limited to the one shown in FIG. 5, and the power supply device 30 may output an AC voltage. Further, the power supply device 30 applies a voltage to the electrodes 16a and 16b of the rotor 12 by periodically switching the polarity and applies a voltage to the electrodes 26a to 26b of the stator 22 while fixing the polarity. It may be. Furthermore, rotor 1
It is not always necessary that 2 has two phases and the stator 22 has three phases. For example, both may have three phases.

(Second Embodiment) A second embodiment of the present invention shown in FIG.
In the electrostatic actuator of the embodiment, the rolling bearings 3A,
3B are both arranged on one surface side (upper surface side in the figure) of the rotor 12.

On the rotating shaft 11, a conductor 34B connected to the insulator 33B and the B-phase electrode 16b (see FIG. 2) is formed. The inner race 3a of one of the rolling bearings 3B is fixed to the upper end of the conductor 34B in the drawing. The insulator 33A and the A-phase electrode 16a are provided on the rolling bearing 3B and the rotor 12 of the insulator 33B (see FIG. 2).
Are formed to be connected to the conductor 34A. The inner race 3a of the other rolling bearing 3A is fixed to the conductor 34A. In the electrostatic actuator according to the second embodiment, the two bearings 3A, 3A
Since B is arranged, the wiring structure of the A-phase and B-phase power supply lines 8A, 8B connected to these bearings 3A, 3B is simplified. Other configurations and operations of the second embodiment are the same as those of the above-described first embodiment.

(Third Embodiment) A third embodiment of the present invention shown in FIG.
In the electrostatic actuator of the embodiment, the rotating shaft 11 has the sliding bearings 36A and 36A made of conductive materials, respectively.
It is rotatably supported by 36B.

One of the sliding bearings 36A is provided with the rotor 12
The conductor 14A connected to the A-phase electrode 16a is in sliding contact with the A-phase power supply line 8A and the sliding bearing 36A and the conductor 1A are connected.
A high voltage is applied to the A-phase electrode 16a via 4A.
Similarly, the other plain bearing 36B has the B
The conductor 14B connected to the phase electrode 16b is in sliding contact with
A high voltage is applied from the phase feeder line 8B to the B-phase electrode 16b via the slide bearing 36B and the conductor 14B. Other configurations and operations of the third embodiment are the same as those of the above-described first embodiment.

[0036]

As is clear from the above description, in the electrostatic actuator of the present invention, the rotor is supplied with power to the rotor electrode via the bearing of the rotating shaft to which the rotor is fixed. There is no need to provide a slip ring and a brush for supplying power to the power supply. Therefore, it is possible to reduce the number of components for power supply, reduce torque loss, and reduce the size of the device in the axial direction of the rotating shaft.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an electrostatic actuator according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a schematic diagram showing the width and pitch of electrodes of a rotor and a stator.

FIG. 5 is a diagram illustrating an example of a voltage waveform applied to electrodes of a rotor and a stator.

FIG. 6 is a sectional view of a main part showing an electrostatic actuator according to a second embodiment of the present invention.

FIG. 7 is a longitudinal sectional view showing an electrostatic actuator according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2A, 2B Mounting member 3A, 3B Rolling bearing 3a Inner ring 3b Ball (sphere) 3c Outer ring 6a, 6b, 6c Connector 8A A-phase power supply line 8B B-phase power supply line 8C U-phase power supply line 8D V-phase power supply line 8E W-phase Power supply line 9 Connector 11 Rotating shaft 12 Rotor 13A, 13B, 33A, 33B Insulator 14A, 14B, 34A, 34B Conductor 15, 25 Insulating layer 16a, 16b, 26a, 26b, 26c Electrode 17A, 17B, 27A, 27B , 27C power supply part 18, 28a, 28b, 28c through hole 22 stator 30 power supply device 36A, 36B sliding bearing

Claims (2)

[Claims] 1. A bearing, a rotating shaft rotatably supported by the bearing, and a plurality of electrodes radially provided on an insulating layer fixed to the rotating shaft. A rotor having a plurality of phases formed thereon, and a stator having a plurality of electrodes radially provided on an insulating layer disposed opposite to the rotor, and connecting the electrodes every predetermined number to form a plurality of phases, Power supply means for applying a voltage with a fixed polarity to the electrode of each phase of one of the rotor and the stator, and applying a voltage with a fixed polarity to the electrode of the other phase; And an electrostatic actuator for rotating the rotor by electrostatic attraction and repulsion acting between the electrodes of the stator, wherein power is supplied to the electrodes of the rotor via the bearing. Electric actuator. 2. The bearing is a rolling bearing including an inner ring, a plurality of spheres, and an outer ring each made of a conductive material; and an insulator fixed to the rotating shaft, and provided on the insulator. The inner ring of the rolling bearing is fixed, and a conductor to which the electrode of the rotor is connected, and a power supply line connected to the outer ring of the bearing, and the power supply line passes through the rolling bearing and the conductor. The electrostatic actuator according to claim 1, wherein power is supplied to an electrode of the rotor.