JPH0213281A - Vibrating motor using piezoelectric elements - Google Patents

Abstract

PURPOSE:To miniaturize and lighten an apparatus by connecting a rotating shaft rotatably fitted into a case through piezoelectric elements arranged along the tangential direction of said shaft. CONSTITUTION:A vibrating motor is equipped with a case 1 shaped into a cylindrical container, a disc type rotating shaft 2 projecting its shank 2a externally of said case 1, piezoelectric elements 3-4, and metal plates 5-6. On the inner surface of said case 1, a plurality of V-shaped metal plates 5 are fixed in positions arranged at equal distances circumferentially as they are respectively directed inwards, and tongue-shaped metal plates 6 are fixed at a plurality of places on the peripheral face of the rotating shaft 2 corresponding to said positions. Also, said piezoelectric elements 3-4 are arranged alternately in the circumferential direction in said metal plates 5-6. Thus, the piezoelectric elements 3-4 are transformed when voltage is applied thereto; its length is shortened or elongated according to the direction of said transformation; the rotating shaft 2 side, to which the metal plate 6 as a free end is fixed, is turned relatively; and the rotating shaft 2 is rotated at a minute angle in the direction of the arrow.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vibration motor that reciprocates a rotating shaft, and particularly relates to a vibration motor using a piezoelectric element.

[Prior Art] A vibration motor can vibrate a driven member by reciprocating a rotating shaft at high speed and engaging a cam or the like attached to the rotating shaft with the driven member. Furthermore, by engaging a one-way gear, this type of motor can also be used as a drive source that rotates in one direction.

Conventionally, this type of motor is configured to rotate a rotating shaft using a magnetic field obtained by passing an alternating current through an electromagnetic coil.

[Problem to be solved by the invention]

The conventional vibration motor described above requires an electromagnetic coil and is therefore large in size, which may make it difficult to apply it to small devices. In addition, there is also the problem that the inertia is large due to the relatively large weight, and there is a limit to the frequency of rotational vibration, making it difficult to obtain high-speed vibration.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vibration motor that is small in size and can easily generate high-speed vibrations.

[Means to solve the problem]

The vibration motor of the present invention includes a cylindrical container-shaped case, a rotating shaft rotatably installed inside the case, and a rotating shaft disposed between the case and the rotating shaft along a substantially tangential direction of the rotating shaft. It includes a piezoelectric element whose both ends are fixed to the inner surface of the case and the circumferential surface of the rotating shaft, respectively, and is configured to apply a high frequency voltage to the piezoelectric element.

[Function] In the above-described configuration, the piezoelectric element alternately repeats the deformation operation of shortening and stretching by applying a high frequency voltage, and this shortening and stretching causes the rotating shaft to rotate relative to the case in opposite directions. .

(Example〕 Next, the present invention will be explained with reference to the drawings.

1 and 2 show one embodiment of the present invention, FIG. 2 is a vertical cross-sectional view at the center position, and FIG.
- It is a cross-sectional view along the A line. In these figures, ■
1 is a cylindrical container-shaped case, and a disc-shaped rotating shaft 2 with a shaft portion 2a protruding outside the case 1 is housed inside the case 1 and is supported for reciprocating rotation. Further, on the inner surface of the case 1, a plurality of V-shaped metal plates 5 are fixed inwardly at positions equally distributed in the circumferential direction. A tongue-shaped metal plate 6 is fixed at the location. And on these metal plates 5 and 6,
Piezoelectric elements 3.4 arranged alternately in the circumferential direction are connected at both ends.

These piezoelectric elements 3 and 4 deform when a voltage is applied, and the length is shortened or expanded depending on the direction of voltage application. Here, one piezoelectric element 3 and the other piezoelectric element 4 are respectively disposed in opposite tangential directions with respect to the rotating shaft 2, and each piezoelectric element 3.4 has a
It is configured to apply high frequency voltages with different phases.

According to this configuration, when a high frequency voltage is applied to the piezoelectric element 3.4, as shown in FIG. 3(a), when the piezoelectric element 3 is shortened, the piezoelectric element 4 is expanded; Since the outer end of is fixed to the inner surface of the case l by the metal plate 5, the rotating shaft 2 side to which the metal plate 6 as a free end is fixed is relatively rotated, and the rotating shaft 2 is rotated in the direction indicated by the arrow. It is rotated by a small angle counterclockwise.

On the other hand, at the next moment, the direction of the high frequency voltage applied to the piezoelectric elements 3 and 4 changes, so the piezoelectric element 3 is expanded and the piezoelectric element 4 is shortened, as shown in FIG. 3(b). . As a result, the rotating shaft 2 is rotated by a small angle clockwise as shown by the arrow.

Therefore, by repeating this operation, the rotating shaft 2
is rotated back and forth at high speed according to the high frequency voltage.

FIG. 4 shows another embodiment of the invention, and is a cross-sectional view similar to FIG. 1.

In this embodiment, the piezoelectric elements 3A are arranged only in one tangential direction of the rotating shaft 2, and are connected to the case 19 and the rotating shaft 2 by metal plates 5.6, respectively.

Further, here, high frequency voltages of the same phase are applied to all the piezoelectric elements 3A.

According to this configuration, since the piezoelectric elements 3A are all oriented in the same direction, the piezoelectric elements 3A can be shortened.

By the extension operation, the rotating shaft 2 can be rotated clockwise and counterclockwise, respectively, and reciprocated.

In each of the embodiments described above, it is possible to obtain stronger torque by increasing the number of arms made up of the metal plate 5.6 and the piezoelectric element 3.4.

〔Effect of the invention〕

As explained above, the present invention has a structure in which a case and a rotating shaft rotatably installed inside the case are arranged along the tangential direction and connected by a piezoelectric element. is shortened by applying
By repeating the deformation operation of extension alternately, the rotating shaft can be rotated relative to the case in opposite directions, and a vibration motor that is small, lightweight, and capable of high-speed vibration can be obtained.

[Brief Description of the Drawings] Fig. 1 shows an embodiment of the present invention, and Fig. 2 shows an embodiment of the present invention.
Fig. 2 is a longitudinal sectional view along the center position of Fig. 1, and Fig. 3(a) and 3(b) are partially enlarged cross-sectional views to explain the action. FIG. 4 is a cross-sectional view of another embodiment of the present invention. l...Case, 2...Rotating shaft, 2a...Shaft portion, 3°3A. 4...Piezoelectric element, 5゜6...Metal plate. Figure ■ Figure 2 Figure a

Claims (1)

[Claims] 1. A cylindrical container-shaped case, a rotating shaft rotatably housed within the case, and a rotating shaft disposed between the case and the rotating shaft along a substantially tangential direction of the rotating shaft, with both ends thereof facing the inner surface of the case. Equipped with a piezoelectric element fixed to the circumferential surface of the rotating shaft,
A vibration motor using a piezoelectric element, characterized in that it is configured to apply a high frequency voltage to the piezoelectric element.