JPH0532992B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ultrasonic motor useful as a drive device in various fields.

(Prior art and its problems) Various motor devices that apply electromagnetic force as a drive source have been widely used for various purposes.
However, in the case of these conventional motor devices, there are certain limitations on their size, weight, rotational force, etc. depending on the materials used, and it is difficult to make them smaller and lighter.

This is because it is limited by the magnetic properties of the materials used.

On the other hand, as an alternative to these conventional motor devices, the applicant has developed a motor device that uses ultrasonic vibrations, that is, a surface wave excited on the surface of an elastic body that is an ultrasonic vibrator. A driving device has been proposed that converts a moving body into unidirectional motion with pressure contact.

By converting the powerful vibrational energy of ultrasonic waves into rotational or linear motion, a small and lightweight motor device is realized.

Although this ultrasonic motor device has attracted attention as having excellent features, there are still concrete issues that need to be improved.

That is, in this ultrasonic motor, a traveling wave is generated due to bending vibration in the rod-shaped elastic body corresponding to the stator, and there is no stationary part. Therefore, it is necessary to support the stator with a spring or an acoustic insulator. The rod-shaped elastic body must be supported in such a way that no force is applied that would damage the vibration system. Furthermore, there is a problem in that efficiency must be taken into account to prevent leakage to the outside through the support.

However, it is actually extremely difficult to completely solve these problems.

Therefore, the present invention supports the rod-shaped elastic body corresponding to the stator of these devices in a low-loss manner, thereby transmitting the vibration energy of the stator to the rotating or moving movable element with high efficiency. The purpose is to provide a high-performance motor device.

(Means for Solving the Problems) The present invention solves the above problems by providing an ultrasonic motor comprising an elastic stator and a movable element, the elastic stator having a support body, This support provides an ultrasonic motor that has a flexural and/or torsional vibration of a natural frequency and that abuts and supports the elastic stator.

(Function) The features of the motor device of the present invention will first be explained in terms of its function.

Figure 1A shows a part of the rod-like elastic stator 1 that causes traveling waves due to bending vibration.If the method of supporting it is to support it at point A on the neutral axis B, the point A is relative to the neutral axis. It is vibrating in the right angle direction, and at the same time it is rotating in rotation around point A. Therefore, as shown in FIG. 1B as a cross-sectional view of the rod-shaped elastic body stator 1, if one end of the elastic body support 2 is fixed at point A and the other end is fixedly supported, the elastic body support 2 will undergo bending vibration and torsion. This will cause vibration.

In order not to affect the vibration system of the rod-shaped elastic body stator 1, the natural frequencies of bending and torsion of the elastic body support 2 are made equal to the frequency of the traveling wave of the rod-shaped elastic body stator 1.

Taking a round bar as an example of the elastic stator 2, in the case of bending vibration, length l = miRC/f-(1) mi: order of vibration mode R: secondary radius of cross section C: speed of sound: frequency of torsional vibration In case, length l = 1/4 G/P-(2) From the formula of G: modulus of elasticity P: density, find the diameter and length of a round bar that satisfies formulas (1) and (2), It turns out that it is sufficient to fix one end to the motor frame.

Therefore, embodiments of the present invention will be described below.

(Example) Example 1 FIG. 2 shows a rotary surface wave motor in which the neutral shaft portion of a ring-shaped elastic body stator 1a is supported by a plurality of spring supports 2a, and the ends of the spring supports 2a are connected to the motor frame 3. An example of a fixed state is shown.

The natural frequency of bending and twisting of the spring support body 2a is made equal to the frequency of the traveling wave of the ring-shaped elastic body stator 1a. And, in the stator 1a,
The movable element 4 is arranged in contact with the movable element 4.

Example 2 Figure 3 shows a rod-shaped elastic stator 1 of a linear motor.
A case is illustrated in which both ends of b are supported by spring supports 2a. A coupler 8 and a vibrator 9 are also attached to the elastic stator 1b.

One end of the spring support body 2a is fixedly supported by the motor frame 3, and the natural frequency due to its bending vibration is made equal to the frequency of the rod-shaped elastic body stator 1b.

Of course, it goes without saying that the spring support body 2a may be integrally formed as a part of the rod-shaped elastic body stator 1b.

Embodiment 3 FIG. 4 shows an embodiment of a supporting method using a sliding body 6 as a support, in which a rod-shaped elastic body stator 1c is
It vibrates with longitudinal and transverse waves, and exhibits motion in a two-dimensional plane.

Therefore, it can be supported by the sliding body 6 that is movable in the vibration direction.

Of course, the feature of this supporting method using the sliding body 6 is that, whereas the above-mentioned supporting method using an elastic body support requires a shape based on natural vibration, the sliding body 6 does not vibrate and can have any shape.

Embodiment 4 FIG. 5 shows an acoustic insulator 5 as a support such as felt or sponge on a ring-shaped elastic stator 1a.
This is an example in which the motor frame is fixedly supported by adhesive bonding.

Generally, when an elastic wave is incident through an interface between two media, if there is a large difference in the characteristic acoustic impedance of each medium, most of the incident wave will be reflected and the transmitted wave will be close to zero.

In particular, elastic bodies such as metals have a large characteristic acoustic impedance, whereas felt, sponge, etc. have a very small characteristic acoustic impedance, and it has been found that these materials can serve as sufficient acoustic insulators.

(Effects of the Invention) With this invention, as explained in detail above,
By supporting the elastic body corresponding to the stator with the support without damaging its vibration, power can be transmitted to the movable element with high efficiency, and a higher performance motor device can be obtained.

[Brief explanation of the drawing]

FIG. 1A is a side view of a rod-shaped elastic stator, FIG. 1B is a sectional view of the rod-shaped elastic stator, FIG. 2 is a sectional view of a rotary ultrasonic motor supported by a spring support, and FIG. The figure is a side view of a rod-shaped elastic stator supported and fixed, Figure 4 is a side view of a rod-shaped elastic stator supported by a sliding body, and Figure 5 is a sectional view of a rotary motor supported by an acoustic insulator. It is. 1... Elastic body stator, 1a... Ring-shaped elastic body stator, 1b... Rod-shaped elastic body stator, 1c... Rod-shaped elastic body stator. 2...Elastic body, 2a...Spring, 3...Motor frame, 4 Mover, 5...
Acoustic insulator, 6...Sliding body, 8...Connector, 9...
... vibrator.

Claims (1)

[Scope of Claims] 1. An ultrasonic motor consisting of an elastic stator 1 and a movable element 4, the elastic stator 1 having a support 2, which has a bending characteristic of a natural frequency. An ultrasonic motor that has vibration and/or torsional vibration and that comes into contact with and supports an elastic stator 1. 2. Claim 1, wherein the support body 2 is a sliding body 6 movable in parallel to the vibration direction of the elastic body stator 1.
Ultrasonic motor as described in section. 3. The ultrasonic motor according to claim 1, wherein the support body 2 is an acoustic insulator 5.