JPS61295881A - Vibration wave motor - Google Patents

Abstract

PURPOSE:To obtain uniform contacting state by constructing to contact a movable unit with a vibrator by a contacting member of spherical contact supported by many elastic units displaceably. CONSTITUTION:A movable unit 3 is formed of a ringlike structure 3a, a ringlike elastic unit 3b made of rubber or sponge bonded to the structure 3a, and many semispherical contacts 3d bonded to the unit 3b. The unit 3 is combined with the vibrator 2 with an electrostrictive element 1 to form a vibration motor. The unit 3 is contacted with the vibrator 2 by the contacts 3d. The vibrator 2 is made, for example, of metal material such as brass or copper having low internal loss of vibration energy. The contacts 3d has wear resistance, and uses a quenched copper or ceramic material or metal or plastic surface-treated with wear resistance.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a so-called vibration wave motor that frictionally drives a moving body in contact with the vibrating body by progressive vibration waves generated in the vibrating body, particularly the moving body. It is related to the structure of

[Background of the invention]

A known example of a vibration wave motor will be schematically explained with reference to FIGS. 4 and 5. Reference numeral 1 indicates an electromechanical energy conversion element such as an electrostrictive element or a magnetostrictive element, for example, PZT (lead zirconium titanate). Reference numeral 2 denotes a ring-shaped vibrating body made of an elastic material, and the electrostrictive element 1 is adhered to one side of the vibrating body. The vibrating body 2 is a stator (not shown) together with an electrostrictive element.
held on the side. Reference numeral 3 designates a moving body, which in this example forms a ring plate-shaped rotor that is pressed into contact with the other surface of the vibrating body 2 . A plurality of electrostrictive elements 1 are arranged in the circumferential direction of the vibrating body 2), and some groups of the electrostrictive elements 1 are arranged at a pitch shifted from other groups by 1/4 wavelength of the wavelength λ of the vibration wave. be done. The electrostrictive elements in the group are arranged at a pitch of A wavelength so that adjacent ones have opposite polarities.

In a vibration wave motor with such a configuration, when a full AC voltage of Vo-8inωT is applied to the electrostrictive elements in one group, and an AC voltage of VcvO-COSωT is applied to the electrostrictive elements in the other group, each electrostrictive element becomes An alternating current voltage is applied to the two groups, with polarities opposite to each other and a phase shift of 90° between the two groups, causing vibration. This vibration is transmitted to the vibrating body 2F
Bending photography is performed according to the arrangement picture of the i-electrostrictive element 1. This bending vibration occurs in such a way that the vibrating body 2 protrudes at every other electrostrictive element position and then retracts at every other electrostrictive element position. On the other hand, as described above, one group of electrostrictive elements is shifted by 1/4 wavelength from the other group, so that bending vibration progresses in the direction in which the voltage elements are arranged. While the AC voltage is being applied, vibrations are excited one after another and become progressive bending vibration waves that propagate in the circumferential direction of the vibrating body 2″f!.

The progress state of the wave at this time is shown in Figure 5 (a), (b), and (e).
(d) Ic is shown. Now, the progressive bending vibration wave is pointing to arrow X! Suppose you move in the direction. If 0 is the central plane of the vibrating body in the resting state, this central plane is the neutral plane 6 shown by the chain line in the vibrating state, and the stress due to bending is balanced on this neutral plane 6. Generally, the cross section perpendicular to the neutral plane 6 is 7.
The line of intersection between the cross section 7 and the neutral plane 6 is generally represented by 5, and the point on the line of intersection between the cross section 7 and the surface of the vibrating body 2 on the moving body 3 side is generally represented by P. When specifically expressed, a subscript number will be added. Looking at the cross section 7 perpendicular to the neutral plane 6, no stress is applied to the intersection line 5 of these two surfaces, and the intersection line 5 only vibrates vertically. At the same time, the cross section 7 vibrates left and right with the intersection line 5 as the center. Therefore, point P moves in a combination of vertical and horizontal movements, which will be explained in detail next.

Figure 5 (1) shows the state at an arbitrary point in time), a cross section 7 passing through the intersection line 51t of the plane 0 and the neutral plane 6 and the vibrating body 2.
Point P1 on the line of intersection with the surface of the moving body 3 is the right dead center of the left-right vibration, and only upward movement is possible. Point p corresponding to line 5sic
A motion component in the left direction (in the X direction opposite to the wave traveling direction A motion component in the direction is added.

Thereafter, as the wave progresses, as shown in FIG. 5(b), when the above-mentioned intersection line 51 comes to the positive side of the wave, point Pg moves to the left and at the same time moves upward.

Furthermore, at the time of (ci) in the same figure, the reading point P1 has reached the top dead center of the vertical vibration and makes only a leftward movement.Furthermore, at the time of (a), the reading point P! makes a leftward movement and a downward movement. do.

The wave further advances, moving rightward and downward, moving rightward and upward, and then returning to the state shown in the figure (&). Other points PS
The same thing can be said for #PSK.

As a result of such a series of motion processes, the point pFi undergoes spheroidal elliptical motion, and the radius of rotation thereof is a function of the length from the neutral plane 6 of the vibrating body 2 to the moving body side surface (that is, to the point P).

On the other hand, since the movable body 3 comes into pressure contact with the vibrating body 2, for example, as typically shown in FIG. The spheroidal motion of the point P1 frictionally drives the moving body 3 in the Xz direction. Not only the point P1 but all the points on the surface of the vibrating body 2 on the movable body 3 side frictionally drive the movable body 3 in the same way as the point P1. The above is the principle of a vibration wave motor.

Now, in order to improve the driving performance of the vibration wave motor, it is necessary that the moving object be in uniform contact with the imaging object. For this purpose, the moving object is divided into multiple pieces,
A structure in which each small piece is supported by an elastic body is shown in JP-A-59-178987 and JP-A-59-183087, but the shape of the contact part of each small piece is either plane or linear. Only an example is disclosed in which the material is pressed against a relatively wide surface. By the way, when a surface or line is divided into small pieces and elastically supported, in order to obtain the desired uniform contact state, each small piece after division must be processed with high surface accuracy, just as before the division. There is a hassle of having to do it. Also, even if a small piece is machined with high surface accuracy, the 6th
As shown in the figure, the pressing force is applied to the small piece 3c of the moving body and the vibrating body 2.
(i.e., if P
), small piece (contact member) 3
A moment is applied to c, and the small piece 3c that was in contact with it as shown by the solid line when no pressure is applied changes to 3a shown by the dotted line in Figures 6 and 7.
', and the contact is not uniform.

[Purpose of the invention]

In view of the above points, the present invention aims to provide a vibration wave motor that can maintain a moving body in a uniform contact state without requiring high surface precision machining.

[Summary of the invention]

In the vibration wave motor of the present invention, the contact portion of the movable body with the vibrating body is composed of a plurality of contact members making spherical contact, and
A feature is that these contact members are supported by elastic members so that they can be elastically displaced independently.

[Embodiments of the invention]

FIG. 1(a) is a side view of a moving body in a first embodiment of the present invention, in which the moving body 3 is a ring-shaped structure 3m.

A ring-shaped elastic body 3b made of rubber, rubber, etc. is bonded to this, and a number of hemispherical contact members 3d are bonded to the elastic body 3b. FIG. 1(b) shows a moving body 3 having such a configuration as a vibrating body 2 with an electrostrictive element 1.
(The structure and function are the same as those described above using FIG. 4 and FIG. 5). ing. The vibrating body 2 is made of a metal material such as brass or steel, which has a low internal loss of vibration energy. Mobile structure 3
A can be made of any material that can maintain its shape, such as metal or plastic. The contact member 3d is made of hardened steel, ceramics, or metal or plastic with wear-resistant surface treatment.

In addition to having the moving body configured as described above, the structure 3a
Even if there is some distortion or deviation in the flatness of the vibrating body 2, the contact members 3d are each elastically supported and follow the vibrating body 2 well, and even surface contact can be obtained. In addition, since the contact member 3d has a spherical shape and makes point contact with the h''Cm moving body 2, the surface precision of the contact portion is not required, and the pressing force is, for example, as shown in Fig. 1(b).
Even if a moment is applied to the contact member 3d by acting on the biased P position shown in the figure, the contact part will only move a little on the sphere as shown by the dotted line in the figure, but the contact state will not change and will be uniform. good contact is maintained. In this way, the surface accuracy of the vibrating body surface and the contact member 3d of the movable body is extremely relaxed, and the position where the pressing force is applied to the vibrating body of the movable body can be arbitrarily selected.

FIG. 2(a) shows a part of a rear view of a moving body according to another embodiment of the present invention, and FIG. 2(b) shows a cross section taken along line AA'.

In this embodiment, the moving body is an elastic disk (for example, a metal plate) 3e.
A radial cut 31″f: is made in each of the hemispherical contact members 3.
d is fixed, and the elastic plate 3• functions as the elastic body 3b in the embodiment shown in FIG. 1, and also serves as the structural body 3&.

FIG. 3(a) is a side view of a moving body according to yet another embodiment,
FIG. 3(b) is a rear view thereof. Said 1st. In the second embodiment, there are a plurality of individual contact members 3d, and it is difficult to manufacture them and adhere them to the elastic body.

Therefore, in the embodiment shown in FIG. 3, each contact member 3d is connected by a thin part 3g made of the same material and having sufficient elasticity, which allows the contact members to be molded at once. Can be made of forged material and also made of elastic material (
3b or 3e) can also be easily bonded.

FIG. 8 shows another example of the contact member 3d that can be used in the present invention, in which the top of the conical shape is made into a spherical shape. As described above, as long as only the contact portion is spherical, the other portions may have any shape depending on the manufacturing process or other circumstances.

〔Effect of the invention〕

According to the present invention, since the movable body contacts the vibrating body with a large number of individually displaceable spherical contact members supported by elastic bodies, a uniform contact state cannot be obtained; Since the surface is spherical, there is no need for high surface precision machining, and even if the contact part is subjected to a moment due to uneven pressure, the contact part will only roll slightly, ensuring a uniform contact condition. . In addition, since the moving body and the vibrating body are in contact as described above, there is no problem caused by an air film between them.
Further, wear particles will not get stuck between these.

[Brief explanation of the drawing]

FIG. 1 (&) is a side view of the moving body according to the first embodiment of the present invention, FIG. (b) is the second embodiment of the present invention, respectively.
The rear view and AA' sectional view of the moving body according to the embodiment, FIGS. 3(a) and 3(b) respectively, and FIGS. FIG. 8 is a sectional view showing a partial state of the improved conventional example, and is a view showing another example of the contact member used in the present invention. 1... Electric-mechanical energy conversion element 2... Vibration plate 3... Moving body 3a... Structure
3b...Elastic body 3e...Elastic plate. Figure 1 (a) Figure 2 (a>

Claims (1)

[Claims] In a vibration wave motor that frictionally drives a moving body that comes into contact with the vibrating body by a progressive vibration wave generated in a vibrating body in which a plurality of electro-mechanical energy conversion elements are arranged and bonded, A vibration wave motor characterized in that the contact part is constituted by a large number of contact members making spherical contact, and each of these contact members is supported by an elastic member so that each contact member can be elastically displaced independently.