JPS6185076A - Vibration wave ring motor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application) The present invention relates to the structure of a vibration wave motor, particularly a traveling wave ring motor that drives a rogue by means of traveling waves.

(Prior art) A vibration wave ring motor that applies a voltage to an electrostrictive element connected to a vibrating body and generates progressive vibration waves in the vibrating body to frictionally drive a movable body that is brought into pressure contact with the vibrating body has been patented. Showa 5
No. 7-206299.

First, such a ring motor will be explained.

In FIG. 1, ■ is an electrostrictive element such as PZT (lead zirconium titanate), which is joined to a vibrating body 2 made of a ring-shaped elastic plate as shown in FIG. It is held and forms the stator. 3 is a movable body rotatably held by the fixed body and brought into pressure contact with the vibrating body 2, forming a rotor. 4 is a vibration absorbing material inserted between the fixed body and the vibrating body 2.

A plurality of electrostrictive elements are bonded together, and one group is arranged with a pitch shifted from the other group by 1/4 wavelength of the vibration wave wavelength.The number of electrostrictive elements in 0 groups is 1. They are arranged at a pitch of /2 wavelengths so that adjacent ones have opposite polarities.

With the vibration wave motor having such a configuration, an AC voltage of V6S inωT is applied to all the electrostrictive elements in one group, and an AC voltage of voCO5ωT is applied to all the electrostrictive elements in the other group. Therefore, the polarity of each electrostrictive element is opposite to that of the adjacent ones.

The two groups are vibrated by applying alternating current voltages with a 90" (Q phase shift). This vibration is transmitted and the vibrating body 2 bends and vibrates according to the arrangement pitch of the electrostrictive elements l. When the electrostrictive element protrudes at the position of , the other every other TL electrostrictive element retracts.

On the other hand, as mentioned above, one group of electrostrictive elements is 1
The bending vibration progresses because they are at positions shifted by 74 wavelengths. While the alternating current voltage is applied, vibrations are excited one after another and propagate through the vibrating body 2 as progressive bending vibration waves.

The progress state of the wave at this time: fS3 diagram (&) (b) (c)
Assume that the progressive bending vibration wave shown in (d) advances in the direction of arrow X. If 0 is the central plane of the vibrating body in the resting state, then in the vibrating state it is in the state shown by the button line 6, and the stress due to bending is balanced on this central plane 6. Looking at the cross section 7 perpendicular to the center plane 6, there is only vertical vibration due to the stress applied at the intersection line 5 of these two planes. At the same time, the cross section 7 is pendulum-oscillating left and right about the intersection line 5. Same figure (
In the state shown in a), a point P on the line of intersection between the cross section 7 and the moving body side surface of the vibrating body 2 is the right dead center of left-right vibration, and is only moving upward. This pendulum oscillation is caused by the fact that when the intersection line 5 is on the positive side of the wave (above the center plane 0), stress is applied to the left (in the opposite direction to the wave's progress), and when the intersection line 5 is on the positive side of the wave (also on the bottom side) ), stress is applied in the right direction.
When the intersection line 5' and the cross section 7' are the former, stress r is applied to the point P', and when the intersection line 5' and the cross section T are the latter, the stress r is applied to the point 〆. As the wave progresses, as shown in b), when the intersection line 5 comes to the positive side of the wave, point P moves to the left and at the same time moves upward. In (C), point P moves only to the left at the top dead center of the vertical vibration.

In (d), it moves to the left and moves downward. The wave further advances, moving to the right and downward, moving to the right and upward, and then returning to the state in (a). When this series of movements is combined, the point P moves in a spheroidal ellipse, and the radius of rotation is a number between t/2, where t is the thickness of the vibrating body. On the other hand, the same figure (C
), on the line where point P is in contact with moving body 3, M of point P is
Due to the movement, the moving body 3 moves in the X direction PH! ! J driven.

2! on the bottom surface of the vibrating body 2 in the left and right direction like the original surface! This causes an elliptical pressure movement accompanied by a movement, and as mentioned above, a large energy loss occurs due to the friction between the absorber and the absorbent material fixed to the fixed body.

(Summary of the Invention) The present invention aims to reduce the energy loss due to friction between the vibrating body and the absorbing body as described above, and improve the efficiency of the motor. By focusing on the fact that there is only vertical vibration and no horizontal vibration on the neutral plane of the vibrating body, the vibrating body is constructed to be supported on this neutral plane.

(Example) Examples will be described below with reference to the figures.

4 to 6 are longitudinal cross-sectional views showing embodiments of a traveling wave ring motor according to the present invention, each of which is constructed substantially the same as that of FIG. 3, and corresponding members are designated by the same reference numerals.

In FIG. 4, the lower part of the ring-shaped diaphragm 2 is shaved off from the center of its thickness near the inner periphery, and the neutral surface is supported on a fixed body (not shown) by an absorbing material. Since the vertical amplitude of the vibrating body is smaller on the inner circumference side, support loss can be minimized by supporting the vibrator at the center plane near the inner circumference in this way.

FIG. 5 shows a configuration in which a step is provided near the outer periphery of the diaphragm 2 to support the neutral plane, which has the advantage of being easy to implement by taking advantage of the annular structure that is a feature of a ring motor.

In FIG. 6, a flange is projected from the outer periphery of the diaphragm 2, and the lower surface of the flange is supported by an absorbent material.

By supporting the vibrating body with the collar in this way, it is possible to absorb the vertical vibration of the vibrating body by utilizing the spring properties of the collar body, and the area of the electrostrictive element can be increased. Good for getting output. This flange may be configured to protrude not only from the outer periphery but also from the inner periphery.

(Effects of the Invention) As described above, the present invention provides a traveling wave ring motor in which the diaphragm is supported on the motor fixed body 1- by an absorbing material at its neutral plane, so that the diaphragm and the absorbing material are connected to each other. Energy loss due to internal friction is reduced, resulting in a highly efficient ring motor.

[Brief explanation of drawings]

Figures 1 to 3 show conventional examples, where Figure 1 is a longitudinal sectional view of a vibration wave motor, Figure 2 is a perspective view showing the shape of the main part of the vibration wave motor, Figure 3 (a), (b), (c),
(d) is a diagram illustrating the driving principle of the vibration wave motor, and FIGS. 4, 5, and 6 are sectional views showing examples, respectively. 1 knee; li strain element; 2: vibrating body; 3: rotor. 4. Absorbent material

Claims (1)

[Claims] In a traveling wave ring motor that generates a bending traveling wave in the elastic plate by applying an alternating current voltage to an electrostrictive element connected to the elastic plate, and drives a rotor in contact with the surface of the elastic plate, the elastic plate is moved to its neutral position. A vibration wave ring motor characterized by being supported by a vibration absorbing material on the surface.