JPS6373887A - Travelling-wave type ultrasonic motor - Google Patents

Abstract

PURPOSE:To enhance heat dissipation effect and to make a motor compactsized, by fixing its stator to the cover. CONSTITUTION:In an ultrasonic motor, a stator 5 is constituted by fixing a piezoelectric body 4 to an elastic body 3. Except the part where the stator 5 is secured to a cover 2 and the part where a rotor 8 comes into pressured contact, the stator 5 is formed into a thin disk. by fixing a slider 7 to a ring 6, the rotor 8 is constituted, which is pressed to the stator 5 by the pressure of a belleville spring 6 with a rubber pad 9 clamped between and rotates integrally with a shaft 11. In this way, the damping of oscillation caused by the fixation to the cover 2 of the stator 5 can be reduced to the minimum. As to the temperature raise of motor due to the head generation of the stator 5, the head dissipation effect can be increased by the conduction and dissipation of heat from the stator 5 to the cover 2 and a case 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultrasonic motor driven by a linear traveling wave.

A traveling wave type (including what is called a surface wave motor) ultrasonic motor is, for example, disclosed in Japanese Patent Application Laid-Open No. 58-14868 by the present applicant.
As disclosed in Publication No. 2 (Japanese Patent Application No. 57-29400), a high-frequency voltage is applied to the piezoelectric material to generate ultrasonic elliptical vibration on the stator surface, causing the rotor that is in pressurized contact to rotate slowly. Compared to conventional electromagnetic motors, it has no windings, has a simple structure, is compact because it uses ultrasonic vibration energy, and can obtain high torque at low rotation speeds. Therefore, it is attracting attention because it has the advantages of high response and excellent controllability.

However, when looking at this ultrasonic motor as a functional component, there are almost no known motors that are housed in a case.

An object of the present invention is to provide a traveling wave type ultrasonic motor as follows.

(1) Extremely small and compact ultrasonic motor (2) Ultrasonic motor with excellent heat dissipation (3) Highly efficient ultrasonic motor (4) Ultrasonic motor with easy pressure adjustment Next, implementation will be explained.

FIG. 1 shows a side view, FIG. 2 shows a top plan view, and FIG. 3 shows a bottom plan view.

Structure〉 2 is a cover for the wooden motor neck, and ■ is a case. FIG. 4 shows a cross-sectional view taken along the line A-A in FIG. As can be seen from the cross-sectional shape shown in Figure 2, this stator 5 is made into a thin disk shape except for the part fixed to the cover 2 and the part where the rotor 8 (to be described later) contacts under pressure. When the piezoelectric body 4 is excited by the frequency, the attenuation of vibration due to the fixation of the stator 5 to the cover 2 can be suppressed to a minimum. This can increase efficiency. Furthermore, the increase in motor temperature due to the heat generated by the stator 5 is caused by the increase in motor temperature from the stator 5 to the cover 2. By conducting and dissipating the heat to the case 1, the structure has a large heat dissipation effect with very little heat.

Next, a slider 7 is fixed to the ring 6, forming a rotor 8. This rotor 8.

The rubber body 9 is narrowed and pressed against the stator 5 by the pressing force of the flat spring 6, so that it rotates integrally with the shaft 11. Note that the pressing force can be adjusted very easily since the thickness of the shim 12 is appropriately selected and adjusted, and then the shim 12 is held by the snap ring 13. Further, the rubber body 9 allows the elastic vibration generated in the rotor 8 to be transmitted to the shaft 1.
It has the effect of absorbing vibrations that prevent it from being transmitted to the 1st.

By the way, by providing a groove in the contact portion of the elastic body 3 with the slider 7, the heat dissipation effect is extremely high, the frictional heat due to pressurization is dissipated, and a motor with stable frictional force can be obtained.

(Function) When two or more types of high-frequency voltages are applied to the polarized piezoelectric body, an elastic traveling wave is generated in the stator 5. This traveling wave causes elliptical vibration in the mass points on the surface of the stator 5. , the slider 7 in pressurized contact is driven in the opposite direction to the traveling wave by the frictional force caused by its elliptical vibration, so the rotor 8 and shaft 11 that are integrated are driven in the opposite direction to the traveling wave.
rotates.

As described above, the present invention is a compact ultrasonic motor in which the stator is fixed to the cover 2 to enhance the heat dissipation effect, and the rotor is brought into pressurized contact with the stator using a spring. You can expect it.

(1) By using a counter spring, a large pressure force can be generated in a small space, and the product can be made smaller and more compact.

(2) Due to the structure that effectively dissipates the heat generated by the stator,
Less deterioration due to heat.

(3) High efficiency due to partially thin-walled stator structure that reduces damping of stator vibrations.

(4) Adjustment of the pressurizing force between the rotor and stator is extremely easy as it is done using a counter spring and shims.

[Brief explanation of the drawing]

Fig. 1.2 Side view of one embodiment of the present invention Fig. 2: Top plan view of the present invention No. 3N: Bottom plan view of the invention No. 4N: A cross-sectional view taken along line A-A in Fig. 1 of the present invention 1...・Case, 2...Cover 5...Stator, 8...Rotor 14.15...Bearing

Claims (1)

[Claims] The stator, which has a piezoelectric body fixed to an elastic body, is fixed to a cover, and the stator has a slider fixed to an elastic ring, and is in pressurized contact with a rotor that is integrated with an output shaft via a spring. The pressing force is adjusted by the counter spring and the spacer, and is held by a snap ring.On the other hand, by applying two or more types of high frequency voltages to the piezoelectric body constituting the stator, the stator is A traveling wave type ultrasonic motor, characterized in that an elastic traveling wave is generated in the rotor to frictionally drive the rotor that is in pressurized contact with the rotor.