JP3137153B2 - Ultrasonic motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a structure of an ultrasonic motor,
In particular, the structure of the contact part of the ultrasonic motor vibrating body with the moving body,
And an electronic device using the ultrasonic motor.

[0002]

2. Description of the Related Art The structure of a vibrating body of a conventional ultrasonic motor is
A description will be given based on FIG. In the vibrating body 201, a plurality of displacement enlarging portions 202 are integrally formed in an annular shape. Displacement enlargement section 20
The second end has chamfers 203 formed at four ends on the outer periphery, and has a contact surface 204 that comes into contact with the moving body.

For example, Japanese Patent Application Laid-Open No. 63-283475 discloses a conventional structure. Next, the operation of the ultrasonic motor will be described with reference to FIGS. In the ultrasonic motor of FIG. 3, elliptical traveling waves (a) to (d) are generated in the displacement magnifying section 202 provided on the vibrating body 201 as illustrated.

FIGS. 4A to 4D show actual states of the states (a) to (d) of the elliptical traveling wave shown in FIG.
The operation will be described in (d). First, in FIG. 4A, a contact surface 204 provided at an end of the displacement enlarging portion 202 is provided.
At the end 204A of the moving body 210, and lifts the moving body 210.

In FIG. 4B showing the next state, the contact surface 204 provided on the displacement magnifying portion 202 and the moving body 21
0 comes in contact and moves it to the left in the figure. In FIG. 4C showing the next state, an end 204B of the contact surface 204 provided on the displacement magnifying portion 202 comes into contact with the moving body 210 and separates therefrom.

In FIG. 4D showing the next state, the displacement enlarging unit 202 returns to the original position while being separated from the moving body 210. By repeating the above operation, the moving body 210
Moves to the left in the figure.

[0007]

In the structure of the conventional ultrasonic motor as described above, the contact portion between the moving body and the displacement expanding portion of the vibrating body changes in a line, a plane, and a line, so that the contact pressure is reduced. There has been a problem that the system becomes unstable, the efficiency of the ultrasonic motor is reduced, and noise is generated.

It is an object of the present invention to provide an ultrasonic motor having high efficiency and low noise.

[0009]

In order to solve the above-mentioned problems, in the present invention, the contact surface of the displacement enlarging portion provided on the vibrating body with the moving body is formed into a smooth curved surface. Further, the curved convex portion is formed by non-cutting processing such as forging or casting.

[0010]

[Function] By making the contact surface of the displacement enlargement portion of the vibrating body with the moving body a smooth curved convex, the contact between the contact surface of the displacement enlargement portion provided on the vibrating body portion and the moving body is always a line or a point. Only, there was no change in the contact pressure.

Therefore, the moving body contacts the enlarged displacement portion of the vibrating body and moves smoothly and quietly.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) First Embodiment A first embodiment of the present invention will be described below with reference to the drawings.
FIG. 6 shows the structure of the first embodiment of the ultrasonic motor according to the present invention. The center shaft 121 is fixed to the support plate 120. The piezoelectric element 105 is bonded and fixed to the vibrating body 101 on the side of the support plate 120. A part of the vibrating body 101 is provided with a comb-shaped displacement enlarging portion 102 in an annular shape. The vibrating body 101 includes the support plate 12
It is fixed to the center shaft 121 so as not to contact with zero.

A sliding plate 111 is adhered and fixed to a contact portion of the vibrating body 110 with the displacement expanding portion 102 in order to reduce frictional resistance and prevent scraping. The moving body 110 is provided with a bearing 112 at a central portion, and assembled with a central shaft 121. The moving body 110
The spring 123 comes into contact with the displacement expanding section 102 provided on the vibrating body 101 at a predetermined pressure. The spring 123 is supported by a spring retainer 124 and a spring receiver 122. The spring retainer 124 is fixed to the center shaft 121 by a screw 125. The spring force is applied to the bearing 122 provided at the center of the moving body 110 via the spring receiver 122, and the moving body 110 is
1 at a predetermined pressure. The lead wire 130 is electrically connected to an electrode (not shown) of the piezoelectric element 105.

Next, the structures of the vibrating body and the moving body according to the present invention will be described with reference to FIGS. In FIG. 1, a plurality of displacement enlarging portions 102 are integrally formed in a vibrating body 101 in an annular shape. The end of the displacement enlarging portion 102 of the vibrating body 101 has a contact surface 104 that is hemispherically convex in the direction of the moving body 101. The end of the displacement expanding portion 102 of the vibrating body 101 may be convex in a part of a hemisphere in the direction of the moving body 101.

Contact surface 1 of vibrating body 101 with moving body 101
04 can be formed by cutting, but is preferably formed by non-cutting such as forging or casting. When processed by forging or casting, the surface is smooth and uniform. In particular, when processed by forging, the strength of the contact surface is sufficiently ensured.

Next, the operation will be described. In FIG. 5A, a contact surface 1 provided at an end of the displacement enlarging portion 102
At one point 104A on 04, it comes into contact with moving body 110 and lifts it. In FIG. 5B showing the next state, the mobile terminal 110 is brought into contact with the moving body 110 at a point 104B at the center on the contact surface 104 on which the displacement enlarging part 102 is provided, and is moved to the left in the figure.

In FIG. 5C showing the next state, the moving body 110 comes into contact with the moving body 110 at another point 104C on the contact surface 104 provided on the displacement enlarging section 102 and separates therefrom. In FIG. 5D showing the next state, the displacement enlarging unit 102 returns to the original position while being separated from the moving body 110.

By repeating the above, the moving body 110 moves to the left in the figure. (2) Second Embodiment Next, a second embodiment of the ultrasonic motor of the present invention will be described. In FIG. 7, the moving body is provided with a plurality of displacement enlarging portions 702 in an annular shape. The displacement expanding portion 702 of the moving body has a semi-cylindrical convex contact surface 704 whose axial direction is aligned with the center of the vibrating body and whose curved surface is aligned with the direction of the moving body.

(3) Third Embodiment Next, a third embodiment of the ultrasonic motor according to the present invention will be described. In FIG. 8, reference numeral 802 denotes a plurality of displacement enlarging portions provided on the vibrating body in a ring shape, and has a contact surface 804 which is curved in the direction of the moving body and has an aspherical convex shape.

Contact surface 704 of vibrating body with moving body 101
Can be formed by cutting, but is preferably formed by non-cutting such as forging or casting. As a pressing unit for pressing the vibrating body 101 and the moving body 110 at a predetermined pressure, an elastic body such as a spring is preferably used.

The contact surface of the vibrating body with the moving body 101 is preferably a part of a spherical surface having an arbitrary curvature, a continuous shape of a curved surface having a plurality of curvatures, or an arbitrary aspherical surface. It can also be formed in the shape of a parabola. (4) Fourth Embodiment Further, using the ultrasonic motor of the present invention, a power transmission unit that operates integrally with the moving body 110 of the ultrasonic motor, and an output unit that operates based on the operation of the power transmission unit With this configuration, an electronic device with an ultrasonic motor can be realized.

As the power transmission means, a transmission wheel such as a gear or a friction wheel is preferably used. As output means,
Preferably, hands are used in an electronic timepiece, a film feeder or a lens drive is used in a camera, a blade feeder or a workpiece feeder is used in a machine tool, and an arm is used in a robot.

As the electronic device with an ultrasonic motor according to the present invention, preferably, an electronic timepiece, a camera, a printer, a printing machine, a machine tool, a robot, a moving device, and the like can be realized.

[0024]

According to the present invention, as described above, the contact surface of the displacement enlarging portion provided on the vibrating body in contact with the moving body has a smooth convex shape on the curved surface in the direction of the moving body. Since the contact position between the moving body and the vibrating body moves smoothly, the following effects are obtained.

(1) Since there is no change in the contact pressure between the moving body and the vibrating body, a highly efficient ultrasonic motor can be obtained. (2) A low-noise ultrasonic motor can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a first embodiment of a vibrating body of an ultrasonic motor according to the present invention.

FIG. 2 is a perspective view of a vibrating body of a conventional ultrasonic motor.

FIG. 3 is a partial enlarged view for explaining the movement of a traveling wave in a displacement expanding section of a vibrating body of a conventional ultrasonic motor.

FIG. 4 is a partial enlarged view of a displacement increasing portion of a vibrating body and a moving body of a conventional ultrasonic motor during driving.

FIG. 5 is a partial enlarged view of the first embodiment of the displacement enlarging portion of the vibrating body of the ultrasonic motor according to the present invention and a moving body being driven.

FIG. 6 is a partially cutaway perspective view of the first embodiment of the ultrasonic motor according to the present invention.

FIG. 7 is a partially enlarged perspective view of a second embodiment of the vibration body of the ultrasonic motor according to the present invention.

FIG. 8 is a partially enlarged perspective view of a third embodiment of the vibration body of the ultrasonic motor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Vibration body 102 Displacement enlargement part 104 Contact surface 104A Contact point 104B Contact point 104C Contact point 105 Piezoelectric element 110 Moving body 111 Slide body 112 Bearing 120 Support plate 121 Center shaft 122 Spring receiver 123 Spring 124 Spring retainer 125 Screw 130 Lead wire 201 Vibrating body 202 Displacement enlargement part 203 Chamfer 204 Contact surface 204A End 204B End 210 Moving body 702 Displacement enlargement 704 Contact surface 802 Displacement enlargement 804 Contact surface

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Akihiro Iino 6-31-1, Kameido, Koto-ku, Tokyo Seiko Electronic Industries Co., Ltd. (56) References JP-A-2-26278 (JP, A) 63-277479 (JP, A) Hikaru 3-77292 (JP, U)

Claims (3)

(57) [Claims] A piezoelectric element, a vibrating body to which the piezoelectric element is fixed, a plurality of protrusions standing in an annular shape from a part of the vibrating body, and an expansion and contraction movement of the piezoelectric element in contact with the protrusion. A moving body that is frictionally driven by the generated vibration, wherein the protrusion has a circular cross-sectional shape, and a shape of a portion in contact with the moving body is a hemisphere or a part of a hemisphere. Ultrasonic motor. 2. The ultrasonic motor according to claim 1, wherein said vibrator is formed by non-cutting processing. 3. An ultrasonic motor according to claim 1 , wherein the ultrasonic motor operates according to an operation of the power transmission unit, the power transmission unit operating integrally with the moving body. An ultrasonic motor having output means.