JPH0191676A - Progressive wave type ultrasonic wave motor - Google Patents

Abstract

PURPOSE:To generate the output of high torque at high efficiency and obtain the ultrasonic wave motor of the long span of life, by arranging an oscillating unit for generating an elliptical oscillation in a specified surface area, and a rotor coming in pressure contact with its surface area and driven frictionally. CONSTITUTION:This ultrasonic wave motor is composed of a stator 5 consisting of an elastic unit 3 and a piezoelectric unit 4, a rotor 8 consisting of a ring 6 and a slider 7, a shaft 11, a case 1, and a cover 2. The rotor 8 is pushed against the stator 5 by the pressure of a flush head spring 10, and is rotated integrated with the shaft 11 via the flush head spring 10. When two or more sorts of high frequency voltage is applied to the piezoelectric unit 4 in this composition, then an elliptical oscillation is generated in the specified surface area of the stator 5 by an elastic progressive wave. Accordingly, the slider 7 is frictionally driven in the fixed direction by the elliptical oscillation, and so the rotor 8 and the shaft 11 which are integrated with each ether are rotated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an ultrasonic motor driven by an elastic traveling wave.

Traveling wave type ultrasonic motors (including those called surface wave motors) are disclosed, for example, in Japanese Patent Application Laid-Open No. 58-14868 by the present applicant.
As disclosed in Publication No. 2, ultrasonic elliptical vibrations are generated on a predetermined surface of the stator (vibrating body) by applying a high frequency voltage to a piezoelectric body fixed to an elastic body. It gives rotation/transfer motion to the rotor/moving body that comes into contact with pressure by friction drive, and compared to conventional electromagnetic motors, it has no windings, has a simpler structure, and uses ultrasonic vibration with high energy density. Because it uses energy, it is small, low speed, and high torque, and has high responsiveness and excellent controllability.
These motors have recently been attracting attention from various quarters.

However, in order to increase the efficiency and torque of this motor, it is necessary to increase the pressure force between the rotor and stator, and in this regard, there is a need to improve the pressure contact area between the rotor and stator. There is.

An object of the present invention is to provide the following traveling wave type ultrasonic motor.

(1) Ultrasonic motor with high efficiency (2) Ultrasonic motor that outputs high torque (3) Ultrasonic motor with long life Next, embodiments will be described.

Structure> Fig. 1 is a side view showing the external appearance, and Fig. 2 is a plan view, where ■ indicates a case of the ultrasonic motor, and 2 indicates a cover serving as a body. or.

FIG. 3 shows the A-AIIf plane in FIG. 2. Now, to explain the fiS3 diagram, a piezoelectric body 4 such as a piezoelectric ceramic is fixed to an elastic body 3 constituting a stator (vibrating body) 5.

The rotor 8 that comes into pressurized contact with the stator 5 has a ring 6 and a slider 7 made of high-performance engineering plastic or high-performance rubber that has a high coefficient of friction and low wear.
is fixed. Depending on the purpose, of course ring 6
In some cases, the rotor 8 is made of the same material as the slider 7 and forms the rotor 8.

The rotor 8 is pressed against the stator 5 by the pressing force of a flat spring 10, and rotates integrally with the shaft 11 via the flat spring 10.

The pressing force is adjusted by the thickness of the shim 12 and then kept constant by the snap ring 13.

The output of this motor can be extracted by assembling pulleys and gears to the shirt 11. (Not shown) Now, like general electromagnetic motors, this ultrasonic motor exhibits so-called drooping characteristics, but if you want to obtain a motor with high efficiency and large output torque, It is necessary to increase the pressing force between the rotor 8 and the stator 5 by using the spring spring 10. Conventionally, the pressurizing force was several kg (
Since the stator size (φ60) was relatively small, mutual surface alignment of the rotor 8 and stator 5 in the pressurized state,
Regarding the contact surface pressure, the motor characteristics were sufficiently satisfactory even without taking into account the elastic deformation during pressurization.

However, as shown above, when trying to increase the efficiency and torque of this ultrasonic motor, the pressurizing force is as high as 10 kg, so it is necessary to apply pressure to the rotor 8 or stator 5. It was found that elastic deformation greatly affects motor characteristics.

Next, a case where the rotor undergoes elastic deformation due to pressurization will be described.

As shown in FIG. 4, the rotor 8 is in state a before being pressurized, and when constant pressure is applied after pressure adjustment, it is in state b due to the elastic deflection of the rotor member.

As can be seen, only the inner circumferential portion of the slider 7 is in contact with the elastic body 3 of the stator 5 during pressurization, resulting in a pressure distribution as shown in FIG. p is blood pressure, which is higher toward the inner circumference and is uneven inside and outside, resulting in abnormal wear of the slider and low output torque of the motor. Therefore, as shown in the present invention, when designing and processing the rotor, it has become necessary to determine the elastic deflection of the rotor when pressurized in advance, and to process the rotor according to the amount of the deflection.

Specifically, as shown in Fig. 6, if the slider 7 of the rotor 8 is to be lapped, it will be lapped with a demarcation plate with a curvature p corresponding to the deflection due to the pressing force, and if it is machined, it will be lapped. Machining is performed at a gradient θ. Since the width B of the contact portion of the rotor 8 with the stator is smaller than the diameter A, sufficient uniform contact can be achieved even on a curved surface plate during lapping.

The case where the pressure is applied to the inner periphery of the rotor 8 has been described above, but if the pressure is applied to the outer periphery, the lap
In r, a rotating surface plate is used, and machining is performed at a constant slope.

Further, when the stator 5 is elastically deformed, the contact surface with the rotor is processed based on the same idea as in the case of the rotor.

Furthermore, if both the rotor 8 and the stator 5 are to be shaped by pressure, either or both should be processed optimally depending on the conditions.

Although the above refers to rotation, it is also possible to process linear types in the same way.

Effect> When two or more types of high frequency voltages are applied to the piezoelectric body 4 which has undergone alternating polarization treatment, elliptical vibration is caused in a predetermined surface area of the stator 5 by elastic traveling waves.

The slider 7 that comes into pressurized contact is frictionally driven in a fixed direction by its elliptical vibration, so that the rotor 8 and shaft 11, which are integrated, rotate.

As described above, the present invention is an ultrasonic motor in which the mutual contact surface pressure is uniform and constant when the rotor and stator are in pressurized contact, and the following first-order effects can be expected.

(1) The pressurized contact between the rotor and stator is uniform and constant, resulting in high efficiency and high output torque.

(2) Since the contact surface pressure is uniform, the amount of wear is stable, so the life is extended.

[Brief explanation of the drawing]

FIG. 1 is a side view of one embodiment of the present invention, FIG. 2 is a plan view of the present invention, FIG. 3 is a sectional view taken along line A-A in FIG. 2, FIG. 4 is a detailed view of the rotor, and FIG. 6 is an enlarged view of the distribution state of the pressurizing force and the pressurizing contact portion, and FIG. 6 is a processed view of the rotor. 9... Rubber body, 14.15... Jokichi of bearing drawing (no change in content) Figure 1 Figure 2 Figure 3 Figure 5 Figure 6 Figure 4 Procedure correction Type (method) % formula % 1 Indication of the case Japanese Patent Application No. 1983-314366 2 Name of the invention Traveling wave type AM sound wave motor 3 Relationship with the 19 amendments Patent applicant location Tokyo 1 (Kasuya, Taya Ward) 2-1-8 March 31, 1988 (Start gate) 5 Subject of amendment 1) As attached (no change in content) 2) As attached (no change in content)

Claims (1)

[Claims] 1) A vibrating body that generates elliptical vibration in a predetermined surface area, and a rotor that is in pressurized contact with the surface area and is driven by friction.
A traveling wave type ultrasonic motor consisting of a moving body, characterized in that mutual contact surface pressure during pressurization is uniform and constant. 2) The traveling wave type ultrasonic motor according to item 1, wherein in the rotor/moving body, mutual contact surface pressure is uniform and constant in a state of elastic deformation of the rotor member due to pressurization. 3) The traveling wave type ultrasonic motor according to item 1, wherein in the vibrating body, mutual contact surface pressure is uniform and constant in a state of elastic deformation of the vibrating body member due to pressurization.