JPS6185078A - Rotary driver - Google Patents

Abstract

PURPOSE:To simplify the structure by radially polarizing a circular vibrator, and equally dividing one of electrodes on the inner and outer peripheral surface into four or more, thereby forming a vibration wave motor of sole electrostric tive element. CONSTITUTION:A circular vibrator 1 made of a ceramic electrostrictive element is radially polarized inside into positive and outside into negative, equally divided at the inside into four to provide polarized electrodes 3. The outside becomes an earth side electrode 3. Further, a semicircular pressure contacting inner ring 5 is disposed through a contactor 4 on the inner peripheral surface, and similar semicircular pressure contacting outer ring 6 is provided on the outer peripheral surface. The rings 5, 6 are pressed to pressure contacting the vibrator 1 by pushing and pulling springs 9, 11. Thus, when an alternating voltage of phase displacement of 2pi/x is applied to the electrode 3 of the inner peripheral surface to obtain the excitation of a traveling wave, and a driven unit contacted with the electrodes 2, 3 can be rotated in the width having no node over the entire periphery.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a rotary drive body using a vibration element applied to a vibration wave motor or the like.

<Prior Art> Rotational drive bodies using vibrating elements such as the electrostrictive elements are disclosed in Japanese Patent Application Laid-open Nos. 148682-1982, 96881-1981, and 96882-1982.

In both of these devices, a plurality of electrostrictive elements are combined in an annular shape, each polarized in the circumferential direction, and by applying an alternating voltage, the end face is excited in a phase difference in the circumferential direction and propagates to the end face. It generates waves and rotates the driven body that is in contact with the end face.

<Problems to be Solved by the Invention> However, in the conventional device, it is necessary to arrange a plurality of electrostrictive elements each polarized in the circumferential direction in an annular shape, resulting in a complicated structure.

The object of the present invention is to provide a rotary drive body composed of a single electrostrictive element.

Means for Solving the Problems> The present invention comprises polarizing an annular vibrating element made of an electrostrictive element or a magnetostrictive element in the radial direction, providing electrodes on the inner and outer circumferential surfaces thereof,
One of the inner and outer electrodes is divided into equal parts by a number X of four or more, and each divided electrode is divided by 2π/
It is characterized in that an alternating voltage of vos inωL with a temporal phase shift of x is applied, and a driven body is pressed against the inner and outer peripheral surfaces of the annular vibration element or one surface thereof.

Note that the pressure contact of the driven body to the circumferential surface of the annular vibrating element in the above configuration may be either direct pressure contact or indirect pressure contact.

− Effect> The operating principle of the present invention will be explained.

One of the typical vibration modes of a toroidal ring is expansion and contraction in the circumferential direction (M wave) called an extension mode, which is unique to a toroidal ring, and this also has displacement in the radial direction. Therefore, when the traveling wave of the extension moat is excited, all the mass points of the ring move in an elliptical manner as shown in FIG. 2, and a propulsive force can be obtained at the side periphery of the ring.

In order to generate this excitation, in the present invention, the annular vibration element l is polarized in the radial direction as shown in FIG. V6 with a temporal phase shift of 2π/x for each of four or more divided electrodes 3
When an alternating voltage of s i n ωt was applied, it was possible to obtain extension mode traveling wave excitation as expected.

As a result of optically measuring this radial amplitude using a photonic sensor, it was possible to confirm a knot-free amplitude over the entire circumference as shown in FIG. When this vibration trajectory was observed under a microscope, it was found that all points of the ring were moving in a circular motion.

So, what about the internal and external electrodes? , 3, when the driven body was pressed against the driven body, a propulsive force was generated, causing rotation of the driven body.

Note that the number of divisions is four or more, and if the number of divisions X is less than three, knots will occur in the swing width, and the propulsive force at that part will decrease. Moreover, if the number of divisions is large, the amplitude distribution in the radial direction becomes uniform.

<Example> 4-6 show one embodiment of the present invention.

Here, the annular vibration element 1 is made of a ceramic electrostrictive element such as PZT, and is polarized in the radial direction so that the inner side is positive and the outer side is negative. The inner circumferential surface is divided into four equal parts, and divided electrodes 3 are provided in each quarter. Furthermore, a semicircular press-welding inner ring 5.5 is disposed on the inner circumferential surface of the ring 5.5 via the contact piece 4, and a contact piece 4.
A semi-circular pressure contact outer ring 6.6 is provided via. Arc-shaped passage holes 7.7 are formed at both ends of the pressure-welding inner rings 5, 5, respectively, and an annular connecting rod 8°8 is inserted into the passage holes, and a pressing spring 9.9 is inserted around the circular connecting rods 8.9. is fitted externally. Further, spring hooks 10 and 10 are fixed to the outer circumferential surface of both ends of the press-contact outer ring 6.6, and tension springs 11.11 are respectively hung in the through holes thereof.

For this reason, the pressure contact inner ring 5.5 is biased by the push spring 9.9 in the direction of pressure contact with the inner surface of the fNiN diary circular movement element 1, and the pressure contact outer ring 6, 6' is urged by the tension spring 11.11. It is biased in a direction in which it comes into pressure contact with the outer surface of the annular vibration element 1 .

As shown in FIG. 6, the contactor 4 is made to have a thickness of about 1 mm by overlapping vinyl sheets, etc., and its width is smaller than the width of the annular vibration element 1. A clearance is created between the pressure-welding inner ring 5 and the pressure-welding outer ring 6, and the inner and outer electrodes of the annular vibrating element 1 are connected to each other. , 3, it is possible to connect the lead wires to Jli.

Voltages of V and sinωL are applied to the four divided electrodes 3 with a temporal phase shift of π/2 in the circumferential direction.

FIG. 7 is a plot of the rotational speed of the pressure welding outer rings 6, 6 (pressure contact inner rings 5, 5) against the current when the annular vibrating element l is fixed and the other is rotatable in such a configuration. It is.

In the above example, as shown in the figure, 30 mA
It was possible to obtain high speed rotation of 12 Orpm.

The above-mentioned rotary drive body uses the press-contact outer rings 6, 6 (press-contact inner rings 5, 5) directly as driven bodies, or the press-contact outer rings 6
, 6 (press-contact inner rings 5, 5), the driven body can be rotated.

FIG. 8 shows a further embodiment of the embodiment, in which a circle B20 is brought into contact with the inner surface of the annular vibration element 1, and a shaft 21 protrudes from the center of the disk 20 to hold it unrotatable. At the same time, a driven body 22 is fitted around the outer periphery of the annular vibration element 1 . Further, on the upper surface of the annular vibration element l, terminals 23 connected to the divided electrodes 3 are exposed in an insulating manner, making it possible to supply voltages with different temporal phases to each divided electrode 3. Furthermore, a terminal 24 connected to the earth side electrode 2 is exposed on the lower surface of the annular vibrating element 1 to facilitate its grounding.

In this configuration, since the disc 20 is fixed, the annular vibration element 1 and the driven body 22 rotate, and the driven body 22 rotates at twice the rotation speed of the annular vibration element 1. I will do it.

Instead, if the fixed body is brought into contact with the outer circumferential side of the annular vibrating element 1, the above-mentioned I! It is also possible to cause A20 to rotate at high speed.

Further, in each of the embodiments described above, in order to prevent wear of the annular vibration element 1, a ring made of a wear-resistant material is bonded to the inner and outer peripheral surfaces of the annular vibration element 1, and through the ring,
The pressure rings 5 and 6 or the disk 20 and the driven body 22 may be brought into contact with each other.

In addition, in the embodiments described above, any of the inner and outer electrodes in contact with the annular vibrating element 1 may be a divided electrode. Further, the number of divisions is four or more, and if the number of divisions is X, each 2π/
An alternating voltage with a temporal phase shift of x is applied. If the number of such divisions is large, the amplitude distribution in the radial direction becomes uniform.

<Effects of the Invention> As described above, the present invention polarizes the annular vibration element 1 in the radial direction, and provides the electrodes 2.3 on the inner and outer circumferential surfaces of the annular vibration element 1. is divided into equal parts by a numerical value X of four or more, and the temporal phase of each divided electrode is shifted by 2π/x in the circumferential direction. Since an alternating voltage of S1nωt is applied and the driven body is pressed against the circumferential surface of one annular vibrating element 1 to rotate the driven body, the rotating part/movement is caused only by - annular vibrating elements. It has excellent effects such as a simple structure.

[Brief explanation of drawings]

The attached drawings show an embodiment of the present invention, and Fig. 1 is a plan view showing the basic configuration, Fig. 2 is a principle diagram, Fig. 3 is a graph showing the swing width, and Fig. 4 is an exploded perspective view of the first embodiment. , FIG. 85 is a perspective view of the same assembly, FIG. 6 is a longitudinal side view, FIG. 7 is a graph showing the relationship between current and rotation speed of the driven body, and FIG. 8 is a longitudinal side view of the second embodiment. . 1: Annular vibrating element 2: Earth side electrode 3: Split electrode 4: Contactor 5: Pressure-welding inner ring 6; Pressure-welding outer ring 20; Disc 22; Driven object Applicant: 1 person from NGK Spark Plug Co., Ltd.
Sadayuki Ueba Agent Patent Attorney Kitao Matsuura Pa 1 Figure 3 Figure 1 Tatsunaka 11 50 Figure 4 Figure 6 Figure 80 Figure 7 Electronics (mA)

Claims (1)

[Claims] An annular vibrating element made of an electrostrictive element or a magnetostrictive element is polarized in the radial direction, electrodes are provided on the inner and outer peripheral surfaces of the element, and one of the inner and outer electrodes is equally divided by a number x of four or more. and applying an alternating voltage of Vosinωt with a temporal phase shift of 2π/x to each of the divided electrodes in the circumferential direction, and pressing a driven body to the inner and outer circumferential surfaces of the annular vibration element or one surface thereof. A rotary drive body characterized by