JPH0787765A - Spherical actuator and its assembling method - Google Patents

Abstract

PURPOSE:To uniformly bring every stator into contact with the surface of a rotor and to as semble a spherical actuator precisely and easily. CONSTITUTION:One fixed stator and three adjustable stators 7, 8, 9 are installed at a casing 1, and the individual stators 6 to 9 are brought uniformly into contact with a rotor 4 by the adjustable stators 7, 8, 9. When they are assembled, the fixed stator 6 is attached to the casing 1, the fixed stator is then positioned by uniformly bringing the surface of the rotor 4 into contact with its surface. Them, the adjustable stator 7 in a position facing the fixed stator 6 is brought uniformly into contact with the rotor 4, and the rotor 4 is held from both sides. Then, the residual adjustable stators 8, 9 are pressed sequentially to, and brought uniformly into contact with, the surface of the rotor 4.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a spherical actuator and a method for assembling the same. Specifically, the present invention relates to techniques for precisely positioning multiple stators.

[0002]

2. Description of the Related Art FIG. 8 is an explanatory view showing a rotor holding structure in a conventional spherical actuator and its problems. In this spherical actuator 61,
The bases of the stators 62a, 62b, 62c, and 62d are slidably held by the casing 63, and the stators 62a to 6a-6
2d is displaceable in the axial direction, and four stators 6
The rotor 64 is held by pressing 2a to 62d against the surface of the rotor 64 from four directions. The center C of the rotor 64 is the axial centers P1, P2, P of the stators 62a to 62d.
4, the four stators 62a to 62 in a state of matching with P4.
the required stator, for example 62a, 6
When ultrasonic vibration is generated in 2c, the rotor 64 is rotationally driven around the shaft centers P1 and P3 of the stators 62a and 62c.

With such a structure, the stator 62a
Axis portions P1 to P4 of a portion of the contact member 62 to 62d that contacts the rotor 64
Depends on the machining accuracy of the casing 63 that holds the stators 62a to 62d and the stators 62a to 62d. However, in reality, the four stators 62a to 62d are
It is very difficult to precisely match the shaft centers of the four stators 62a to 62d, as shown in FIG.
P4 and the center C of the rotor 64 are easily displaced, and it was almost impossible to uniformly contact all the stators 62a to 62d with the surface of the rotor 64. Therefore, in the conventional spherical actuator 61, the stators 62a to 62d and the rotor 64 make one-sided contact, and the rotor 6 is caused by this one-sided contact.
4 causes a decrease in drive torque for rotating the motor 4, uneven rotation, and the like, and the rotation speed characteristic of the rotor 64 deteriorates.
There is a problem that the energy conversion efficiency of the spherical actuator 61 becomes low. In addition, the positioning characteristics of the rotor 64 are deteriorated, and the rotor 6 by the stators 62a to 62d is
The holding property of No. 4 was also deteriorated.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the drawbacks of the above-mentioned conventional examples, and its object is to make it possible even if the casing for holding the stator has a processing error or the like. It is an object of the present invention to provide a spherical actuator capable of rotatably holding a rotor in a state where the axial center of a portion of each stator that contacts the rotor and the center of the rotor are aligned, and an assembling method thereof.

[0005]

A spherical actuator of the present invention is a spherical actuator in which a plurality of stators are brought into pressure contact with the surface of a substantially spherical rotor to generate minute vibrations in the stator to drive the rotor to rotate. One of the plurality of stators is a fixed stator, and the other stator is an adjustable stator whose position can be adjusted so as to uniformly contact the surface of the rotor.

Also, in the method of assembling the spherical actuator of the present invention, the rotor is positioned by bringing the surface of the rotor into uniform contact with the fixed stator, and then another adjustable stator is brought into contact with the surface of the rotor evenly. It is characterized in that the spherical actuator is assembled by adjusting the position.

[0007]

In the present invention, since one fixed stator and a plurality of adjustable stators whose positions can be adjusted are provided, after the rotor is positioned so that the surface of the rotor is brought into uniform contact with the fixed stator, the other stators are not changed. The adjusting stator can be adjusted so as to sequentially contact the surface of the rotor uniformly.

Therefore, even when the stator holding portion is off the center of the rotor, it is possible to assemble the fixed stator and the adjustable stator so that the shaft centers of the fixed stator and the adjustable stator coincide with the center of the rotor. Can be eliminated. Moreover, by sequentially assembling the fixed stator, the rotor, and each adjustable stator,
Each stator can be brought into contact with the rotor surface uniformly one by one with the fixed stator as a reference, and the spherical actuator can be assembled accurately and easily.

[0009]

1 is a partially cutaway plan view showing the structure of a spherical actuator A according to an embodiment of the present invention. In this spherical actuator A, a substantially spherical or substantially spherical shell-shaped rotor 4 is housed in a cavity 3 of a casing 1 having a substantially circular window 2 opened therein. Rotor 4 is cavity 3
It is supported only by the fixed stator 6 and the adjustable stators 7, 8, 9 arranged on the same circumference without contacting the inner wall surface of the. In addition, 5 is an arm protruding from the outer peripheral surface of the rotor 4.

Each of the stators 6, 7, 8 and 9 is shown in FIG.
It is composed of a rotary type surface acoustic wave oscillator having a structure as shown in (b) (however, in the case of the stators 7, 8 and 9, the protrusions 2 are formed on the protrusion 11
5 is provided). That is, the elastic body 10 made of an elastic material such as metal has a substantially dish shape, and the contact pieces 12 are projected and arranged in a ring at a constant pitch on the outer peripheral surface of the elastic body 10. Elastic body 10 corresponding to 12
A piezoelectric element 13 such as PZT is attached to the back surface of the outer peripheral portion of the. Each of the stators 6, 7, 8 and 9 is adapted to support the rotor 4 by bringing the contact piece 12 into contact with the rotor 4 as shown in FIG.
A concave rounded surface 12a having the same curvature as that of the surface of the rotor 4 is provided on the upper surface of the.

Each of the stators 6, 7, 8 and 9 drives the rotor 4 according to the same principle as that used as an ultrasonic motor, and vibrates the piezoelectric element 13 to bring the elastic body 10 into contact. The surface wave vibration such as flexural vibration or stretching vibration is generated on the surface of the piece 12.
Then, when the piezoelectric element 13 is driven in a predetermined driving mode, particles on the surface of the contact piece 12 move in an elliptical orbit by a traveling wave (deflection traveling wave) traveling in the circumferential direction on the surface of the elastic body 10. , The surface of the rotor 4 is the stator 6, 7,
It moves along the circumferential direction of 8 and 9. As a result, the rotor 4 rotates around the axis of each stator 6, 7 or 8, 9.

Reference numeral 6 is a fixed stator for rotating the rotor 4 around an axis parallel to the X axis, and reference numeral 7 is an adjustable stator for rotating the rotor 4 around an axis parallel to the X axis. Reference numerals 8 and 9 are adjustable stators for rotating the rotor 4 around an axis parallel to the Y axis. Any pair of stators 6, 7 and 8, 9 are arranged so as to sandwich the rotor 4 from both sides. The fixed stator 6 is an elastic body 1.
The protrusion 11 protruding to the center of the back surface of the casing 0
It is fixed to the base 14 fitted in. Further, the adjustable stators 7, 8 and 9 are adapted to perform Oldham operation in the casing 1, and the stators are housed in the straight holes 15 of the casing 1 so as to be slidable in the axial direction and non-rotatable. It is held by the holding portion 16 via the Oldham portion 17. Further, a load cell case 19 is provided between the stator holding portion 16 and the base 18 fitted in the casing 1.
The load cell 20 put in is stored slidably,
A disc spring 21 is inserted between the load cell case 19 and the stator holding portion 16, and the screw 2 screwed into the base 18 is inserted.
The tip of No. 2 is in contact with the load cell 20. Therefore, the contact pressure between the stator 6, 7, 8, 9 and the rotor 4 can be adjusted by rotating the screw 22 while monitoring the output of the load cell 20.

FIG. 3 is an exploded perspective view showing in detail the holding structure of the adjustable stators 7, 8 and 9 operating in Oldham.
Square grooves 23 and 24 are formed on both the front and back surfaces of the Oldham section 17 over the entire width.
3, 24 are oriented in a direction twisted by 90 degrees with respect to each other. The protrusions 11 of the adjustable stators 7, 8 and 9 have rectangular protrusions 25.
The protrusion 25 is slidably inserted into the groove 23 of the Oldham portion 17, and the protrusion 25 can slide smoothly along the direction of the groove 23. Groove 23
It is inserted without rattling in the direction orthogonal to. Similarly, a protrusion 26 having the same cross section as the groove 24 is also provided on the surface of the stator holding portion 16, and the protrusion 26 is also slidably inserted into the groove 24 of the Oldham portion 17. The ridge 26 can slide smoothly only in the direction of the groove 24. Therefore, the adjustable stators 7, 8 and 9 are connected to the stator holding portion 16 via the Oldham portion 17, and the adjustable stators 7, 8 and 9 are connected to the stator holding portion 16.
Although it can be freely eccentric in the direction perpendicular to the axis of the shaft, it is constrained from rotating with respect to the stator holding portion 16 about the axis.

When assembling this spherical actuator A, first, the fixed stator 6 is attached to the casing 1, then the rotor 4 is delivered into the cavity 3 of the casing 1, and the surface of the rotor 4 contacts the contact piece 12 of the fixed stator 6. The rotor 4 is positioned so as to be evenly adhered to the. Then, the adjustable stator 7 and the stator holding portion 16 are attached to the casing 1 at a position facing the fixed stator 6, and the adjustable stator 7 is pressed against the surface of the rotor 4 by the disc spring 21. At this time, even if the axial center of the stator holding portion 16 is deviated from the center of the rotor 4 by δ, when the adjustable stator 7 is pressed against the surface of the rotor 4 by the elastic force of the disc spring 21 or the like, the adjustable stator 7 is moved. The shaft center of the adjustable stator 7 is eccentric along the curve of the surface of the rotor 4 to coincide with the center of the rotor 4, and the surface of the rotor 4 is contacted exactly and uniformly. At the same time, the rotor 4 is sandwiched and fixed by the fixed stator 6 and the adjustable stator 7 from both sides. Then, one of the remaining adjustable stators 8, 9 is attached to the casing 1, for example one adjustable stator 8,
The adjustable stator 8 is pressed against the surface of the rotor 4 in a direction orthogonal to the direction in which the rotor is held. Due to this pressing force, the adjustable stator 8 is displaced and brought into uniform contact with the surface of the rotor 4. Finally, the remaining adjustable stator 9
Is attached to the casing 1, and the adjustable stator 9 is pressed against the surface of the rotor 4 by the elastic force of the disc spring 21. Due to this pressing force, the adjustable stator 9 is also displaced and brought into uniform contact with the surface of the rotor 4. Thus, as shown in FIG. 4, each stator 6, 7, 8,
The spherical actuator A can be assembled in a state where the axis of 9 and the center of the rotor 4 are aligned.

Alternatively, another assembly method may be as follows. That is, the fixed stator 6 and the adjustable stators 7, 8 and 9 are attached to the casing 1 in advance, and all the adjustable stators 7, 8 and 9 are attached to the rotor 4.
And the rotor 4 is positioned only on the fixed stator 6. Then, the screw 22 is tightened to bring the adjustable stator 7 at a position facing the fixed stator 6 into pressure contact with the rotor 4 to uniformly contact the adjustable stator 7 and the rotor 4. After that, the other adjustable stators 8 and 9 may be sequentially brought into pressure contact with the rotor 4 so as to be evenly contacted with the surface of the rotor 4.

The three adjustable stators 7, 8 and 9 are pressed against the surface of the rotor 4 at a time so that the rotor 4 and each stator 6,
When trying to make 7, 8, 9 evenly contact, each adjustable stator 7, 8, 9 cannot be freely displaced, so that each stator 6, 7, 8, 9 cannot be evenly contacted with the rotor 4. . On the other hand, by sequentially adjusting the rotor 4 and the adjustable stators 7, 8 and 9 as described above, the stators 6, 7, 8 and 9 can be surely brought into uniform contact with the surface of the rotor 4. Therefore, the assembling work of the spherical actuator A can be facilitated. In addition, not all of the stators are adjustable stators, but one is a fixed stator. Therefore, after positioning the rotor 4 with the fixed stator 6 as a reference, each adjustable stator 7, 8, 9
Can be sequentially adjusted to be in contact with the surface of the rotor 4 uniformly, and the assembling work can be further simplified.

Therefore, when the rotor 4 is rotated around the axis parallel to the X axis, the fixed stator 6 and the adjustable stator 7 are driven to generate a traveling wave on the surface of the stators 6, 7 and 7. To rotate the rotor 4. At this time, the displacement of the stator holding portion 16 is absorbed by the Oldham portion 17 on the side of the stator 6, and since both the stators 6 and 7 are in uniform contact with the surface of the rotor 4 over the entire circumference, the rotation speed and the rotation torque of the rotor 4 are increased. Can be prevented and uneven rotation can be prevented. Similarly, when the adjustable stators 8 and 9 are driven to rotate the rotor 4 around the axis parallel to the Y axis,
Adjustable stator Since the stators 8 and 9 are in uniform contact with the rotor 4, the rotor drive characteristics can be improved.

Moreover, each of the adjustable stators 7, 8 and 9 operates in Oldham's direction and can be eccentric in the direction perpendicular to the axis, but cannot rotate about the axis, so the rotor 4 is rotating. Adjustable stators 7,8,
9 does not rotate in the opposite direction to the rotor 4. As a result, the loss of the drive torque of the rotor 4 due to the slippage (rotation) of the adjustable stators 7, 8, 9 can be prevented, and the drive characteristics of the rotor 4 can be maintained in a good state.

The structure of the adjustable stator is not limited to the above structure, and any structure may be used. For example, also in the Oldham mechanism, a protrusion may be provided in the Oldham portion, and a groove may be provided in the stator and the stator holding portion.
Alternatively, the Oldham portion may be provided with the concave groove and the protrusion, and the stator and the stator holding portion may be provided with the protrusion and the concave groove. Further, various methods of holding the adjustable stator as described below may be used.

FIG. 5 is an exploded perspective view showing another holding structure for the adjustable stators 7, 8, 9. A square plate-shaped intermediate member 31 is interposed between the adjustable stators 7, 8 and 9 and the square plate-shaped stator holding unit 16, and the stator holding unit 16 and the intermediate member 31 are cylindrical. Of the intermediate member 31 and the adjustable stator 7, 8,
9 are also connected by a cylindrical roller 33. That is, the rollers 32 and 3 are provided on the front and back surfaces of the intermediate member 31, respectively.
Concave grooves 34 and 35 having an arcuate cross section shallower than the radius of 3 are provided, and both concave grooves 34 and 35 are oriented in a direction twisted by 90 degrees. The stator holding portion 16 is provided with a concave groove 36 having an arcuate cross section, which is shallower than the radius of the roller 32, and the protrusion 11 on the back surface of the adjustable stator 7, 8, 9 is shallower than the radius of the roller 33. A concave groove 37 having an arcuate cross section is provided. Thus, the stator holding portion 16 and the intermediate member 3
The rollers 1 and 1 are connected from both sides so as to sandwich the rollers 32 in the recessed grooves 36 and 34, and the intermediate member 31 can rotate around the rollers 32 within a range not contacting the stator holding portion 16. In addition, the intermediate member 31 and the adjustable stators 7, 8, 9
Are connected from both sides so that the rollers 33 are sandwiched in the concave grooves 35, 37, and the adjustable stators 7, 8, 9 are connected.
Can be rotated around the roller 33 (the swinging direction orthogonal to the swinging direction of the intermediate member 31) within a range where the intermediate member 31 is not contacted.

Therefore, the stator holding portion 16 is delivered in the straight hole portion 15 opened in the casing 1 in the shape of a square hole, and the position can be adjusted only in the axial direction. Intermediate member 31
Since the adjustable stators 7, 8 and 9 are housed in the casing 1 so as to be freely movable, the adjustable stators 7, 8 and 9 are
Can swing at a small angle to the axis.
Therefore, even if the axial center of the stator holding portion 16 is deviated from the center of the rotor 4, if the adjustable stators 7, 8 and 9 are pressed against the surface of the rotor 4 by the elastic force of the disc springs 21 or the like, the adjustable stator is adjusted. 7, 8 and 9 swing their heads along the curve of the surface of the rotor 4, and the axial centers of the adjustable stators 7, 8 and 9 coincide with the center of the rotor 4, and the adjustable stator 7,
8, 9 and rotor 4 are in close contact. Moreover, since the rollers 32, 33 are fitted in the concave grooves 36, 34, 35, 37, the adjustable stators 7, 8, 9 are restrained from rotating about the axis with respect to the stator holding portion 16. Has been done. As a result, the stators 6, 7, 8 and 9 are connected to the rotor 4
It is prevented from hitting one side, and the rotor drive characteristics are improved.

FIG. 6 is an exploded perspective view showing still another holding structure for the adjustable stators 7, 8, 9. Here, arcuate ridges 38 and 39 having arcuate cross-sections are provided on both the front and back surfaces of the square plate-shaped intermediate member 31, and the arcuate ridges 38 and 39 are twisted by 90 degrees with respect to each other. It is facing. A groove 40 having an arcuate cross section, which is shallower than the protruding height of the arcuate projection 38, is provided in the stator holding portion 16 over the entire length, and the projection 1 on the rear surface of the adjustable stator 7, 8, 9 is formed.
1 is provided with a concave groove 41 having an arcuate cross section that is shallower than the protruding height of the arcuate ridge 39. Thus, the stator holding portion 16 and the intermediate member 31 have the arc-shaped protrusion 38 and the concave groove 40.
The intermediate member 3 is rotatably fitted into the intermediate member 3 and connected.
1 can be rotated around the concave groove 40 within a range where it does not contact the stator holding portion 16. Further, the intermediate member 31 and the adjustable stators 7, 8 and 9 are connected by fitting the arcuate ridge 39 into the concave groove 41 so as to be rotatable, and the adjustable stator 7,
8 and 9 are arc-shaped protrusions 3 within a range not contacting the intermediate member 31.
It can rotate around 9. Although illustration is omitted, the intermediate member 31 is provided with the concave grooves 40 and 41, and the stator holding portion 16 is provided.
And adjustable stators 7, 8 and 9 each have an arcuate ridge 3
8, 39 may be provided. Alternatively, the intermediate member 31 is provided with the concave groove 40 (or 41) and the arcuate projection 39 (or 38), and the stator holding portion 16 is provided with the arcuate projection 38 (or the groove 4).
0) and the adjustable stators 7, 8, 9 may be provided with the concave groove 41 (or the arcuate ridge 39).

FIG. 7 is an exploded perspective view showing another holding structure for the adjustable stators 7, 8, 9. In this structure, the adjustable stator 7 is provided by the intermediate member 44 made of an elastic body such as rubber, soft plastic, or synthetic resin foam.
8, 9 and the stator holding portion 16 are connected. The stator holding portion 16 is provided with a concave portion 45 which is shallower than the thickness of the intermediate member 44 made of an elastic body. The intermediate member 44 is housed in the concave portion 45, and the surface of the intermediate member 44 protruding from the concave portion 45 can be formed. The back surfaces of the adjusting stators 7, 8 and 9 are in contact with each other. The contact surface between the stator holding portion 16 and the intermediate member 44 and the contact surface between the intermediate member 44 and the adjustable stators 7, 8 and 9 are
It is preferable that they are integrally molded or adhered to each other, but if the elastic force of the disc spring 21 or the like generates a sufficient frictional force, they may be pressed together. Even if the axial center of the stator holding portion 16 is deviated from the center of the rotor 4, when the adjustable stators 7, 8 and 9 are pressed against the surface of the rotor 4, the intermediate member 44 made of an elastic body is elastically deformed. As a result, the axial centers of the adjustable stators 7, 8 and 9 coincide with the center of the rotor 4, and the adjustable stators 7, 8 and 9 and the rotor 4 come into close contact with each other. Further, when the intermediate member 44 made of an elastic body is used, when the rotor 4 is rotated, the intermediate member 44 is twisted by its reaction and the adjustable stators 7, 8,
9 rotates, but after the intermediate member 44 is slightly twisted at the beginning of rotation of the rotor 4, the intermediate member 44 is not twisted and deformed any more, so that there is no risk of substantially affecting the rotor drive characteristics.

As the holding structure for the adjustable stator, various methods other than the above-described embodiment are possible. For example, a structure such as that found in a general universal joint connects the stator holding portion and the stator. It does not matter even if the stator does not eccentrically move in the direction perpendicular to the axis only by swinging.

[0025]

According to the present invention, since the adjustable stator whose position is adjustable is provided, even when the stator holding portion is off the center of the rotor, the adjustable stator is displaced by being pressed against the rotor. In this way, the axial center of each stator is aligned with the center of the rotor, and each stator can be brought into uniform contact with the rotor surface.

Further, after positioning the surface of the rotor so as to make uniform contact with the fixed stator, and then adjusting other adjustable stators so as to make uniform contact with the surface of the rotor, the fixed stator, the rotor, and By sequentially assembling the adjustable stators in this order, the rotor and each adjustable stator can be accurately and easily assembled with the fixed stator as a reference.

Thus, according to the present invention, it is possible to eliminate a decrease in driving torque for rotating the rotor, uneven rotation, etc., and prevent a decrease in the rotational speed of the rotor, and energy conversion of the spherical actuator. The efficiency can be improved. Further, the rotor can be held securely, and the rotor can be precisely positioned.

Further, since not all the stators are adjustable stators but one is a fixed stator, the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway plan view showing a structure of a spherical actuator according to an embodiment of the present invention.

2 (a) and 2 (b) are a front view and a cross-sectional view showing the above stator.

FIG. 3 is an exploded perspective view showing a mechanism for operating the above stator in Oldham.

FIG. 4 is a schematic cross-sectional view schematically showing a state where a rotor is held by four stators.

FIG. 5 is an exploded perspective view showing another holding structure of the adjustable stator.

FIG. 6 is an exploded perspective view showing still another holding structure of the adjustable stator.

FIG. 7 is an exploded perspective view showing still another holding structure of the adjustable stator.

FIG. 8 is a schematic cross-sectional view for explaining a defect of the conventional example.

[Explanation of symbols]

 1 Casing 4 Rotor 6 Fixed stator 7, 8, 9 Adjustable stator 16 Stator holding part 17 Oldham part

Claims (2)

[Claims] 1. A spherical actuator in which a plurality of stators are pressed against the surface of a substantially spherical rotor to generate minute vibrations in the stator to drive the rotor to rotate, and one of the plurality of stators is fixed. A spherical actuator comprising a stator and an adjustable stator whose position can be adjusted so that the other stator uniformly contacts the surface of the rotor. 2. The method of assembling the spherical actuator according to claim 1, wherein after positioning the rotor by uniformly contacting the fixed stator with the surface of the rotor, another adjustable stator is attached to the surface of the rotor. A method of assembling a spherical actuator, characterized in that the spherical actuator is assembled by adjusting the position so as to make uniform contact.