JPH03118777A - Abrasion removing structure of ultrasonic motor - Google Patents

Abstract

PURPOSE:To remove slippage and to get rid of abrasion from the contact face between a stator and a rotor by decreasing the contact area between the stator and the rotor or the contact area of an abrasion-resistant member, and enlarging the contact area per unit area. CONSTITUTION:An abrasion-resistant member 4 is put between the stator 1 and the rotor 2 of an ultrasonic motor 3 consisting of said stator 1 and rotor 2. When the elliptic vibration of the stator is generated by applying AC voltage to the piezoelectric element (not shown in the figure) of the stator 1, the elliptic vibration is transmitted to the rotor 2 through the abrasion-resistant member 4, but since the contact area of the abrasion-resistant member 4 is small, even if the pressing to the rotor is the same, the contact pressure per unit area becomes large. Accordingly, the rotor 2 rotates without slipping, and also the abrasion of the stator 1 or the rotor 2 can be prevented by the abrasion-resistant member 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wear-removal structure for an ultrasonic motor that eliminates wear and abnormal noise on the contact surface between a stator and a rotor.

[Prior Art] In recent years, various ultrasonic motors using piezoelectric elements have been proposed. This ultrasonic motor uses the vibration of a piezoelectric element to generate traveling waves or elliptical vibrations on the end face of the stator, presses the rotor against the surface where this elliptical vibration is generated, and drives the rotor as the elliptical vibration progresses. be.

[Problems to be Solved by the Invention] However, in this ultrasonic motor, the rotor is pressed against the stator, so when the rotor rotates, the contact surface between the stator and the rotor wears out. The drawback was that it had a shorter lifespan than a motor. Furthermore, there is a drawback in that a squeak is generated at the contact surface between the stator and the rotor, causing discomfort to the user.

In order to eliminate this drawback, it is thought that wear can be reduced by interposing an anti-wear member or oil-less metal in the contact area between the stator and rotor, but the pressing force between the stator and rollers is dispersed and the stator There has been a problem in that the force exerted by the generated elliptical vibration on the roller is reduced, causing the rotor to slip.The present invention reduces the contact area between the stator and rotor or the contact area of the wear-resistant member. The object of the present invention is to provide a wear-removal structure for an ultrasonic motor that increases the contact pressure per unit area to eliminate slip and remove wear on the contact surface between the stator and rotor. .

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a superstructure comprising a stator using a piezoelectric element and a rotor on a surface of the stator that generates traveling waves or elliptical vibrations. In the sonic motor, a wear-resistant member having a smaller contact surface than the contact surface between the stator and the rotor is interposed.

Further, the wear-resistant member may be configured in a ring shape or may be configured in an elliptical ring shape. Further, the wear-resistant member may be configured in the shape of a disc with a large number of through holes, and the oil-impregnated member may be provided in the large number of holes.

In addition, in an ultrasonic motor that combines a stator using a piezoelectric element and a rotor on a surface of the stator that generates traveling waves or elliptical vibrations, an anti-wear material is provided on the contact surface between the stator and the rotor. In addition to intervening,
The contact surface of the rotating body or the contact surface of the stator has a smaller contact area than the contact surface of the wear-resistant member.

Further, the contact surface of the stator or rotor may be configured in a ring shape.

[Operation] According to the present invention, in order to efficiently transmit the elliptical vibration of the stator to the rotor, it is sufficient to increase the contact area of the stator with the rotor, but this causes wear on the contact surface. to remove it.

If a wear-resistant member having the same contact area as the contact area between the stator and the rotor is used, the rotor will slip because the pressing force of the rotor against the stator is dispersed. Therefore, by reducing the contact area of the stator or rotor with the wear-resistant member, the pressing force per unit area is increased to prevent slipping, and the wear-resistant member reduces wear and reduces abnormal noise. It was designed to eliminate it.

[Example] Referring to FIG. 1, in the wear removal structure of the example of the present invention, a wear-resistant member 4 is interposed between the stator 1 and rotor 2 of an ultrasonic motor 3 consisting of a stator 1 and a rotor 2. let As shown in FIG. 2(a), the wear-resistant member 4 has a ring shape that is smaller than the contact area of the stator 1 or rotor 2 and whose outer diameter is approximately the same as or smaller than the diameter of the stator 1 or rotor 2. to form. Further, as shown in FIG. 2(b), it is formed into an elliptical ring shape whose maximum outer diameter is approximately the same as or smaller than the diameter of the stator 1 or rotor 2. This wear-resistant member 4 is fixed to the stator 1 or rotor 2.

In the ultrasonic motor 3 of this embodiment configured as described above, when an alternating current voltage is applied to the piezoelectric element (not shown) of the stator 1 to generate elliptical vibration of the stator 1, the elliptical vibration is generated by the wear-resistant member 4. However, since the contact area of the wear-resistant member 4 is small, even if the pressure on the rotor 2 is the same, the contact pressure per unit area becomes larger, and the rotor 2 may slip. In addition, the wear-resistant member 4 can prevent wear of the stator 1 or rotor 2.
Since the contact area between the wear-resistant member 4 and the stator is small, abnormal noises such as squeaks do not occur.Furthermore, if the wear-resistant member 4 is configured in an elliptical ring shape as shown in FIG. 2(b), the wear-resistant member 4 and the stator 1 or rotor 2 are not in the same area, so that wear can be further reduced.

In addition, as a material for the wear-resistant member 4, polyimide resin with high wear resistance, wear-resistant metal, etc. can be used.

Further, as another embodiment of the wear-resistant member 4 of the present invention, as shown in FIG. The pressing force is increased, and an oil-impregnated portion 7 is provided in the through hole 6.

In the ultrasonic motor using the wear-resistant member 4 configured in this way, the pressing force per unit area is large, so the rotor 2
rotates without slipping, and stator 1
Alternatively, wear of the rotor 2 can be prevented. Furthermore, by providing an oil impregnated part 7 in the first through hole 6, oil seeps out from the impregnated part 7 when the temperature rises due to friction on the contact surface, softening abnormal rotation and making the rotor 2 rotate smoothly. can do.

In addition, in order to reduce the contact area of the stator 1 or rotor 2, as shown in FIG.
The contact surface 8 of this stator 1 is made to protrude in a ring shape.
may be brought into contact with a disc-shaped wear-resistant member 4 fixed to the rotor 2 as shown in FIG.

In the ultrasonic motor of this embodiment configured as described above, the pressing force per unit area is large, so the rotor 2 can be rotated without slipping, and the wear of the stator 1 can be prevented by the wear-resistant member 4. This eliminates abnormal rotation noise.

In the above embodiment, the contact surface 8 of the stator 1 is formed in a ring shape, but the contact surface of the rotor 2 may be formed in a ring shape.
Alternatively, the rotation speed of the rotor 2 can be changed by changing the diameter of the ring of the stator 1 or the rotor 2.

[Effect of the invention] The present invention is configured as described above.

By reducing the contact area of the stator, rotor, or wear-resistant member, the pressing force per unit area is increased to prevent the rotor from slipping, and the wear-resistant member reduces wear on the stator or rotor. This has the advantage of eliminating abnormal sounds.

[Brief explanation of drawings]

FIG. 1 is a side view of a part of an ultrasonic motor according to an embodiment of the present invention, FIG. 2 is a plan view of a wear-resistant member used in the ultrasonic motor shown in FIG. 4 is a side view and a plan view of a rotor of an ultrasonic motor according to another embodiment of the present invention, and FIG. 5 is an ultrasonic motor using the rotor of FIG. 4. FIG. 3 is a side view of the sonic motor. 1 is a rotor, 2 is a stator, 3 is an ultrasonic motor, and 4 is a wear-resistant member.

Claims (7)

[Claims] 1. In an ultrasonic motor that combines a stator using a piezoelectric element and a rotor on a surface of the stator that generates traveling waves or elliptical vibration, a contact surface between the stator and the rotor that is smaller than the contact surface is formed. A wear removal structure for an ultrasonic motor, characterized in that a wear-resistant member having a surface is interposed. 2. 2. The wear removal structure for an ultrasonic motor according to claim 1, wherein the wear-resistant member has a ring shape. 3. 2. The wear-removing structure for an ultrasonic motor according to claim 1, wherein the wear-resistant member has an elliptical ring shape. 4. 2. The wear removal structure for an ultrasonic motor according to claim 1, wherein the wear-resistant member is configured in a disc shape with a large number of through holes. 5. 2. A wear removal structure for an ultrasonic motor according to claim 1, wherein oil-impregnated members are provided in a large number of through holes of said disc-shaped wear-resistant member. 6. In an ultrasonic motor that combines a stator using a piezoelectric element and a rotor on a surface of the stator that generates traveling waves or elliptical vibration, an anti-wear member is interposed on the contact surface between the stator and the rotor. Also, a wear removal structure for an ultrasonic motor, characterized in that the contact surface of the rotating body or the contact surface of the stator has a smaller contact area than the contact surface of the wear-resistant member. 7. 7. The ultrasonic motor wear removal structure according to claim 6, wherein the contact surface of the stator or rotor is formed into a ring shape.