JPS61170285A - Piezoelectric linear motor - Google Patents

Abstract

PURPOSE:To improve the propulsion force and to smoothly drive a movable body by generating a surface wave on the entire periphery of the outer peripheral body of a rod-shaped elastic unit so that substantially entire periphery of the inner peripheral body of the body receives a frictional force by the surface wave. CONSTITUTION:When an alternating voltage is applied to a transmitting side vibrator 2, the vibrator 2 is vibrated radially. In other words, the vibrator 2 is elongated or contracted radially, and is repeated. Accordingly, a rod-shaped elastic unit 1 secured to the outer peripheral body of the vibrator 2 generates a surface wave on the outer peripheral body (entire surface) to be propagated in a direction of an arrow A. Thus, a movable body 8 mounted on the unit 1 receives a frictional force by the surface wave substantially on the entire periphery of the inner peripheral body, and is driven in a direction of an arrow B which is the opposite direction to the propagating of the surface wave.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a piezoelectric linear motor that generates surface waves in an elastic body using electrostrictive effects and drives a moving body using the surface waves.

[Background technology] This type of piezoelectric linear motor is disclosed in Japanese Patent Application Laid-Open No. 59-12
As disclosed in Japanese Patent Application No. 2385, there is a device that generates surface waves in an elastic body such as a metal by synthesizing longitudinal vibration and transverse vibration of the electrostrictive effect. In this device, one end surface of the elastic body and one end surface of the moving body are placed in pressure contact with each other, but the surface waves necessary to drive the moving body are generated only on a part of the surface of the elastic body. do not have. Therefore, the moving object driven by the frictional force with the surface waves also comes into contact with the non-vibrating portion of the elastic body, and receives the frictional force in the opposite direction to the driving direction, reducing the propulsive force of the moving object. Further, for the same reason, the propulsive force is not uniformly applied to the moving object, which impedes smooth driving of the moving object.

[Object of the Invention] The present invention has been made in view of the above reasons, and its purpose is to provide a piezoelectric linear motor that can improve propulsion force and smoothly drive a moving object. .

[Disclosure of the Invention] A piezoelectric linear motor according to the present invention includes a rod-shaped elastic body having a circular cross-sectional shape, and a disk-shaped elastic body, which is fixed to an outer circumferential body at one end of the rod-shaped elastic body and when an alternating voltage is applied to the rod-shaped elastic body. a wave transmitting side vibrator that vibrates in the radial direction; a wave receiving side vibrator having a disk shape and having a vibration absorbing means fixed to the outer peripheral body at the other end of the rod-shaped elastic body; Sufficiently shorter than the distance between both oscillators,
and a moving body attached to the rod-shaped elastic body so that substantially the entire circumference of the inner circumferential body is in contact with the outer circumference of the rod-shaped elastic body, and the vibration of the wave-transmitting side vibrator causes the rod-shaped elastic body to move. The movable body is driven by surface waves generated on the outer circumference (surface) to improve the propulsive force and to smoothly drive the movable body.

(Example) An example of the present invention will be described below based on FIGS. 1 to 5.

1 is a rod-shaped elastic body made of a metal material and has a circular cross-sectional shape.

Reference numeral 2 denotes a wave transmitting side vibrator made of a piezoelectric element, which has a disk shape, and is fixed to the outer peripheral body of the rod-shaped elastic body 1 at one end.

The wave transmitting side vibrator 2 is provided with electrodes 3 and 4 sandwiching the upper and lower surfaces of a disc, and an alternating voltage such as a sine wave voltage is applied from a drive circuit 5. When an alternating voltage is applied, it vibrates (expands and contracts) in the radial direction.

Reference numeral 6 denotes a wave-receiving side vibrator made of a piezoelectric element, which has a disk shape and is fixed to the outer peripheral body of the rod-shaped elastic body 1 at the other end.

The receiving side vibrator 6 is provided with electrodes 3.4 that sandwich the upper and lower surfaces of the disc, and emits the voltage generated by vibration (expansion and contraction) in the radial direction to a vibration absorbing means 7 such as a resistor. do. In other words, the vibration of the transmitting side vibrator 2 generates a surface wave on the outer circumference (surface) of the rod-shaped elastic body 1, and the receiving side vibrator 6 vibrates (expands and contracts) due to the surface wave and generates a voltage. Then, the voltage is absorbed by the vibration absorbing means 7.

8 is a moving body made of a rigid material, whose axial length is the resonator 2.
．． It is attached to the rod-shaped elastic body 1 in such a way that the length is sufficiently shorter than 6, and substantially the entire circumference of the inner circumferential body abuts the outer circumference of the rod-shaped elastic body 1. Specifically, it is composed of two semi-cylindrical parts 9 and 10, the inner radius of each semi-cylindrical part 9 and 10 is approximately equal to the outer radius of the rod-shaped elastic body 1, and these are joined together. Outwardly protruding coupling pieces 9b and 10b having insertion holes 9a and 10a for connection are formed, respectively.

Then, the semi-cylindrical parts 9 and 10 are butted against each other so as to cover the outer circumference of the rod-shaped elastic body 1, and the bolts 11 are inserted into the insertion holes 9a and 10a. Nut 1 until approximately the entire circumference abuts the outer circumferential circle of rod-shaped elastic body l.
Screw 2 together.

FIG. 6 shows a different embodiment of the moving body 8, which includes the fifth
By adding a pressure spring 13 that is compressed and elastically mounted between the coupling piece 9b and the nut 12 shown in the figure, the movable body 8 and the rod-shaped elastic body 1 are elastically brought into contact with each other, and the contact force can be adjusted. This is what I did.

(Operation) In FIG. 1, when an alternating voltage is applied to the wave transmitting side vibrator 2, the wave transmitting side vibrator 2 vibrates (expands and contracts) in the radial direction as shown in FIGS. 3 and 4. FIG. 3 shows a state in which the transmitting side vibrator 2 is extended in the radial direction, and FIG. 4 shows a state in which it is similarly contracted, and this process is repeated. Therefore, a surface wave is generated on the outer circumference (entire surface) of the rod-shaped elastic body 1 to which the transmitting side vibrator 2 is fixed, and the surface wave propagates in the direction of arrow A. As a result, the movable body 8 attached to the rod-shaped elastic body 1 receives frictional force from the surface waves over almost the entire circumference of its inner circumferential body, and is driven in the direction of arrow B, which is opposite to the propagation direction of the surface waves. .

[Effect of the Invention J] Since the piezoelectric linear motor of the present invention is constructed as described above, surface waves are generated around the entire outer circumference of the rod-shaped elastic body, and moreover, surface waves are generated around the entire circumference of the inner circumference of the moving body. Since it receives the frictional force caused by the surface waves, it improves the propulsion force and has the effect of making it possible to drive the moving object smoothly.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the present invention, in which FIG. 1 is a side view, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. FIG. 4 is a sectional view showing a state in which it is extended in the radial direction, FIG. 4 is a sectional view showing a state in which it is contracted, FIG. 5 is a sectional view showing a mounting structure for a moving object, and FIG. It is a sectional view showing a mounting structure. 1- Rod-shaped elastic body, 2- Transmission side vibrator, 5- Drive circuit, 6
- Receiving side vibrator, 7 - Vibration absorbing means, 8 - Moving object. Patent applicant Matsushita Electric Works Co., Ltd. Patent attorney Toshimaru Takemoto (and 2 others) =7- Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) A rod-shaped elastic body with a circular cross-sectional shape, and a wave transmitting side vibrator that is disk-shaped and is fixed to the outer circumferential body on one end side of the rod-shaped elastic body and vibrates in the radial direction when an alternating voltage is applied. , a wave-receiving side vibrator having a disk shape and having a vibration absorbing means fixed to the outer peripheral body on the other end side of the rod-shaped elastic body; a moving body attached to the rod-shaped elastic body so that substantially the entire circumference of the body abuts the outer circumference of the rod-shaped elastic body; A piezoelectric linear motor that drives the moving object using surface waves generated by the piezoelectric linear motor.