JPS62203571A - Vibration wave motor - Google Patents

Abstract

PURPOSE:To readily apply an AC voltage by providing conductivity at a vibration plate and a movable body, securing an electro-mechanical energy converter to one side of the plate, and applying an AC voltage to the other side face of the converter and the body. CONSTITUTION:A vibration plate 2 is held together with a piezoelectric element plate 1 through a ringlike vibration absorber 4 at a base 5 made of an insulating material. A rotatable circular movable body 3 made of a conductor material is supported by bearing 77 through a bush 8 to a stationary shaft 6. The body 3 is contacted with the upper surface of the body 3 in a pressed stage. The shaft 6, the bush 8 and the bearing 7 are formed of conductive materials, the shaft 6 is electrically conducted with the body 3 to apply an AC voltage between an electrode film formed on the lower surface of the plate and the body 3.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention comprises a vibrating body by arranging and fixing a plurality of electro-mechanical energy converting elements to a diaphragm, and applying an alternating current voltage to the converting elements. In a so-called vibration wave motor configured to frictionally drive a moving body in contact with the vibrating body by a traveling wave of bending vibration generated in the vibrating body, a motor for applying an alternating current voltage to the electro-mechanical energy conversion element is used. Concerning improvements to the configuration.

[Background of the invention]

First, the principle of a vibration wave motor using traveling waves of bending vibration will be explained with reference to FIG. 2 and FIG. 3, which is a bottom view thereof. As shown in the figure, a first group of electro-mechanical energy conversion elements 1a and a second group of electro-mechanical energy conversion elements 1b are arranged on the lower surface of a ring plate-shaped diaphragm 2 made of an elastic body (for example, metal). The array is fixed. These electricity-
Mechanical energy conversion elements include piezoelectric elements, electrostrictive elements,
Alternatively, a magnetostrictive element or the like can be used, but a piezoelectric element will be used as a representative example below.

First, referring to the first group of piezoelectric elements 1a, electrode films (not shown) are provided on the upper and lower surfaces of all the piezoelectric elements 1a, and these electrodes are connected to each other and the upper surface electrodes by electrical connection means (not shown). The lower surface electrodes are electrically connected in parallel, and a voltage is simultaneously applied to each piezoelectric element 1&, and each piezoelectric element is configured to expand and contract in the circumferential direction by applying this voltage. And each piezoelectric element 1a is
Just as nine neighboring items have opposite polarity (i.e.
They are arranged in the circumferential direction with inputs λ and a total pitch of 7 so that when one expands, the other contracts.

The same applies to the configuration and arrangement of the second group piezoelectric elements 1b.

λ The first group 1a and the second group lb are arranged to be shifted by an odd multiple of -. It is also assumed that the length of the entire circumference of the diaphragm 2 is an integral multiple of λ. Note that a portion 1' between the first group 1a and the second group lb is a region to which no voltage is applied and does not actively expand or contract. The diaphragm 2, the piezoelectric elements 1a and 1b, and the portion Y1 form a rectangular body.

In such a configuration and arrangement, when an AC voltage is applied only to the first group piezoelectric element 1a, the diaphragm becomes convex downward in the part where the piezoelectric element 1a extends, and convex upward in the part where the piezoelectric element 1a contracts. As a result of such bending deformation, a standing wave of bending vibration (wavelength λ) is generated over the entire circumference of the vibrating body. In this case, the intermediate position between the voltage λ and the electric element 1m and the positions spaced apart from the intermediate position become nodes. When an AC voltage is applied only to the second group piezoelectric element 1b, a standing wave of wavelength λ is similarly generated, but the position of the node is shifted by 7 compared to the standing wave. It becomes something.

If an AC voltage is applied to the first group piezoelectric element 1a, and at the same time an AC voltage having an electrical phase difference of 900 is applied to the 82nd group piezoelectric element 1b, as a result of the synthesis of standing waves by both, the vibrating body A traveling wave of bending vibration is generated that travels in the circumferential direction, and its traveling direction is determined by the sign of the phase difference between the applied voltages. In this traveling wave of bending vibration, points on the neutral plane of the diaphragm's thickness only vibrate in the vertical direction, but points on the top and bottom surfaces of the diaphragm vibrate in the vertical and circumferential directions. It performs a kind of combined elliptical motion. Therefore, in FIG. 2, the diaphragm 2 is appropriately supported so as not to rotate, and a ring plate-shaped moving body 3 (not shown) is mounted on the top surface of the diaphragm 2.
When pressed into contact with each other, the movable body is driven and rotated by the frictional force caused by the elliptical motion of the diaphragm, and the direction of rotation can be selected by the positive or negative sign of the phase difference between the voltages applied to the piezoelectric element groups 1a and lbO. The above is the principle of a vibration wave motor that uses traveling waves of bending vibration.

By the way, conventionally, in such a vibration wave motor, in order to apply an alternating voltage in the thickness direction of the piezoelectric element, lead wires are attached to the diaphragm 2 made of a conductive material such as metal with a conductive adhesive, or the Vibration plate (or.

Pressure! Connect the conductive resin between the electrode on the surface that connects to the diaphragm of the element and the unnecessary electrode on the back side of the piezoelectric element (the electrode provided at the part corresponding to 1' in Figures 2 and 3) and connect the lead wire from there. was issued. However, pulling out the lead wires from the side of the diaphragm can disturb the vibration of the vibrating body, cause the lead wires to come off due to vibration, and conduct conductivity from unnecessary electrodes in parts of the piezoelectric element that are not applied with voltage and do not actively expand or contract. When connecting with conductive resin, the vibration state changes depending on the amount of conductive resin applied, and the work itself is very troublesome, so when considering mass production, there is a drawback that there is wide variation between individual motors. there were.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vibration wave motor which eliminates the above-mentioned drawbacks and allows application of an alternating current voltage to a piezoelectric element very easily without disturbing the vibration of the vibrating body.

[Summary of the invention]

A vibrating body is formed by arranging and fixing a plurality of electro-mechanical energy conversion elements on one side of a diaphragm, and when an alternating current voltage is applied to the electro-mechanical energy conversion elements, the expansion and contraction action of the electro-mechanical energy conversion elements causes In a vibration wave motor that frictionally drives a moving body that is in pressure contact with the other surface of the diaphragm by a traveling wave of bending vibration that is excited and generated in the vibrating body, the diaphragm and the moving body are electrically conductive. the electro-mechanical energy conversion element is fixed in electrical continuity with one side of the diaphragm, and the alternating current voltage is applied to a surface of the electro-mechanical energy conversion element opposite to the surface to which the diaphragm is fixed. It is characterized in that the voltage is applied between the moving body and the moving body.

[Embodiments of the invention]

FIG. 1 is a partial elevational side view of a vibration wave motor according to an embodiment of the present invention. In FIG. 1, 1 is a ring-shaped piezoelectric element plate on which a first piezoelectric element group 1a and a second piezoelectric element group 1b are arranged with pitch and polarity as described in detail of the invention; Ferroelectric ceramics, such as PZT (lead zirconate titanate)
It is made of. Reference numeral 2 denotes a ring-shaped diaphragm made of a conductive metal such as brass or stainless steel, and the upper surface of the piezoelectric element plate 1 is adhered to the lower surface of the ring-shaped diaphragm 2 using a conductive adhesive.

The diaphragm 2 includes a ring-shaped vibration absorber 4 together with the piezoelectric element plate 1.
It is held on a base 5 made of an insulating material via a T-. 3 is a rotatable circular moving body made of conductive material, and bearing 7
It is rotatably supported by a fixed shaft 6 via a bushing 8. The fixed shaft 6 is fixed to the base 5 and has a screw at the top. The bush 8 is loosely fitted onto the fixed shaft 6, and a spring 9 is fitted to the upper end of the bush 8, and a nut 11 is screwed into the bush 8 through a washer 10. In this case, mobile object 3
is in contact with the upper surface of the diaphragm 2 in a pressed state. On the lower surface of the piezoelectric element plate 1, first piezoelectric element groups I are provided.
Electrode films are provided in regions corresponding to the IL and the second piezoelectric element group 1b, and lead wires are connected to these, respectively. On the other hand, the movable body 3 is in contact with the diaphragm 2 at the peak of the bending vibration wave not only when the motor is stopped but also during driving.

Therefore, by applying an alternating current voltage as described in the background of the invention between each of the lead wires and the movable body 3, an operation as a vibration motor occurs, and the movable body 3 is rotationally driven. In the embodiment shown in FIG. 1, the fixed shaft 6, bushing 8, and bearing 7 are also made of conductive materials, and by providing electrical continuity from the fixed shaft 6 to the movable body 3 through these, the movable body 3 can be moved with the lead wire. An alternating current voltage is applied between the body 3 and the body 3. Of course, the movable body 3 may be electrically connected to the movable body 3 from a brush or the like that directly contacts the movable body 3.

Japanese Patent Application No. 60-65455 describes a type of vibration wave motor that performs linear reciprocating motion using an oblong diaphragm having a straight portion and a curved portion based on essentially the same principle, but this The invention can also be applied to this.

〔Effect of the invention〕

According to the present invention, it is possible to prevent the conventional drawbacks in which the vibration of the vibrating body is disturbed by pulling out the lead wire from the diaphragm, and the lead wire is detached from the vibrating body due to vibration.
The efficiency and reliability of vibration wave motors are significantly improved.

[Brief explanation of drawings]

FIG. 1 is an elevational side view, partially in section, showing one embodiment of the vibration wave motor of the present invention, and FIGS. 2 and 3 are diagrams illustrating the principle of the vibration wave motor. DESCRIPTION OF SYMBOLS 1... Piezoelectric element plate, 1a, lb... 1st group and 2nd group piezoelectric elements, 2...
- Vibration plate, 3... Moving body, 4... Vibration absorber, 5... Base, 6... Fixed axis, 7.
...Bearing, 8...Button, 9...Spring, 1
0...washer, 11...nut. Honta small flat ゛＋−―ψ

Claims (1)

[Claims] A vibrating body is formed by arranging and fixing a plurality of electro-mechanical energy conversion elements on one side of a diaphragm, and when an alternating current voltage is applied to the electro-mechanical energy conversion elements, the expansion and contraction action of the electro-mechanical energy conversion elements causes In a vibration wave motor that frictionally drives a moving body that is in pressure contact with the other surface of the diaphragm by a traveling wave of bending vibration that is excited and generated in the vibrating body, the diaphragm and the moving body have electrical conductivity. The electro-mechanical energy conversion element is fixed in electrical continuity with one side of the diaphragm, and the AC voltage is transferred to the surface of the electro-mechanical energy conversion element opposite to the surface to which the diaphragm is fixed. A vibration wave motor that is characterized by being applied between the vibration wave motor and the body.