JPS61116979A - Supersonic wave drive motor - Google Patents

Abstract

PURPOSE:To enhance the efficiency of a supersonic wave drive motor without causing a disturbing vibration by providing a groove at a distance specially controlled in a stator. CONSTITUTION:A supersonic wave drive motor has a stator 1, a rotor 2, the stator 1 is supported to a stator support provided at a stator stationary base 3, and an exciter 8 bonded with a member of iron for forming a piezoelectric unit and the drive surface 6 is supported. The rotor 2 has a ring-shaped driven surface 9, and a rotational shaft 10 at the center. In this case, a groove 11 is formed on the drive surface 6 of the vibrating member, and the entire thickness t of the member and the depth of the groove 11 are set to 1/5t. Further, one wavelength of the driver is lambda, and when the entire driver is vibrated by supersonic wave (m), the number of the grooves 11 is formed in the vibrating range of mXlambda. Thus, uniform vibration distribution can be obtained in the entire drive surface 6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ultrasonic drive motor using ultrasonic vibration as a drive source.

(Structure of conventional example and its problems) A conventional ultrasonic drive motor includes an ultrasonic drive body (stator part) having a drive surface, and a drive surface melt (stator part) that contacts the drive surface and extracts kinetic energy. It consists of a rotor section).

The driving body includes a piezoelectric body as a driving body excitation part in a part of the driving body, the driving surface of the driving body (stator part) is set perpendicular to the wave front, and the driving surface fusion body (rotor part) is arranged perpendicularly to the wave front. move.

Such ultrasonic drive motors have a simple structure and are therefore widely used in electronic equipment, cameras, medical equipment, and the like.

However, due to its structure, this ultrasonic drive motor only extracts a portion of the vibration components of the stator section as output motion, so it has the disadvantage of low power efficiency.In order to increase power efficiency, it is necessary to use less power and a larger amplitude. However, in reality, due to the presence of internal losses within the solid, large-amplitude vibrations actually lead to a decrease in efficiency.

(Object of the Invention) An object of the present invention is to eliminate the conventional drawbacks and provide an efficient ultrasonic drive motor. (Configuration of the Invention) The ultrasonic drive motor of the present invention has a drive surface. An ultrasonic vibration motor comprising an ultrasonic drive body and a drive surface fusion member that contacts the drive surface of the ultrasonic drive body and extracts a part of the vibration as external motion. The drive surface has a concave cross section. Mizoai & 16□ shape.

6. In addition to the ultrasonic driver,
When one wavelength of the ultrasonic driver is λ, and m (m is an integer greater than 2) ultrasonic waves are excited in the entire ultrasonic driver, and N is a number prime to m, then m×λ The number of the concave portions or convex portions is N within the vibration region. Note that N is greater than m.

Further, the vibration drive section has a shape in which the left and right sides of the vibration section are connected, that is, an annular shape, and a rotor section having a similar structure is configured in contact with this annular shape.

(Description of Embodiment) An embodiment of the present invention will be described based on FIGS. 1 to 3. FIG. 1 is a perspective view of the ultrasonic drive motor, and the second
The figure is a sectional view of the same.

In the figure, 1 is a stator part, and 2 is a rotor part. The stator part 1 has a piezoelectric body 5 and a vibrating member 7 made of iron or the like provided with a driving surface 6 on a stator support part 4 provided on a stator fixing base 3. The rotor part 2 has a driven surface 9 formed in a ring shape and rotates around a rotating shaft 10 at the center.

In this embodiment, a groove 11 is provided in the drive surface 6 of the vibrating member 7. The driving surface has a structure in which waves corresponding to nine wavelengths of the driving ultrasonic waves are placed on the driving surface. If the overall thickness of the vibrating member 7 is t, then the depth of the groove 11 is 215t, and the depth of the groove 1 is 215t.
The number of 1's was set to 91 in the entire ring of the vibrating member 7. This is about five half wavelengths, and the number of wavelengths and the number of grooves are relatively prime.

The in-plane vibration distribution at this time is shown in FIG. As is clear from the figure, it is shown that a uniform vibration distribution is obtained over the entire surface. This is the most important point of the present invention; if an uneven imaging distribution occurs in the in-plane distribution, this will appear externally as unnecessary vibration, but in the present invention,
I don't want these things to happen at all.

Although a concave groove or a convex object may be provided on the vibrating member, this is to prevent the basic vibration form of the ultrasonic vibrator from changing. .

In particular, when the vibrating body and the vibrating body vibrate in combination, they interfere with each other, resulting in so-called beat vibration, which is the sum or difference of two frequencies.

This heat vibration first generates unnecessary vibration in the ultrasonic drive motor, which causes disturbance to the outside as external noise. Second, it results in a decrease in efficiency.

(Effects of the Invention) According to the present invention, by providing the stator portion with concave grooves at appropriately controlled distances, there is an effect of increasing efficiency without causing disturbing vibrations.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an ultrasonic drive motor according to an embodiment of the present invention, FIG. 2 is a sectional view thereof, and FIG. 3 is a vibration amplitude distribution diagram of the rotation angle. DESCRIPTION OF SYMBOLS 1... Stator part, 2... Rotor part, 3... Stator fixing base, 4... Stator support part, 5... Piezoelectric body, 6... Drive surface, 7... Drive surface 8... Excitation part, 9... Driven surface 1, 10... Rotating shaft, 11... Groove. Figure 1 Figure 2

Claims (3)

[Claims] (1) An ultrasonic vibration motor comprising an ultrasonic vibrating member having a driving surface, and a driving surface fusion body that contacts the driving surface and extracts a part of the vibration as external motion, in which the vibrating member A plurality of grooves or convex portions having a concave or convex cross section are provided on the drive surface, and one wavelength of the ultrasonic wave applied to the ultrasonic vibrating member is λ, and the entire ultrasonic vibrating member is covered by m wavelengths (m is When excited with ultrasonic waves (an integer greater than 2), N grooves or protrusions are created within the vibration area of m×λ.
An ultrasonic drive motor characterized in that N is greater than m and prime relative to m. (2) The ultrasonic drive motor according to claim (1), wherein the N is a larger number than m. (3) The vibration drive section is characterized by being composed of a vibration drive section having a shape in which both ends of the vibration section are tied together, that is, an annular shape, and a rotor section having a similar structure in contact with the annular shape. An ultrasonic drive motor according to claim (1).