JPS60174074A - Vibration wave motor - Google Patents

Abstract

PURPOSE:To enhance the drive efficiency and to eliminate a noise by elastically deforming a movable element and contacting it with the vicinity of the top of a traveling vibration wave of a vibrator. CONSTITUTION:A movable element 3 is formed of an elastic plate 3a made of a material having relatively hard and wear resistance such as a stainless steel, titanium or Duralumin, an elastic substance 3b such as rubber, and a structure 3c of metal or plastic. The element 3 is pressure contacted with the vibrator 3, and when a traveling vibration wave of the vibrator 2 is generated, the plate 3a is contacted to be draped with the shape near the top of the vibration wave while elastically deforming. Accordingly, the contacting area of the element 3 and the vibrator 2 is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure of a moving body of a vibration wave motor that frictionally drives the moving body by progressive vibration waves.

FIG. 1 shows a schematic diagram of an embodiment of a vibration wave motor driven by progressive vibration waves, which has recently been put into practical use. In the figure, 1 is an electrostrictive element made of, for example, PZT (lead zirconium titanate), and 2 is a vibrating body made of an elastic material, to which the electrostrictive element 1 is bonded.

The vibrating body 2 and the electrostrictive element 1 are held on the stator (not shown) side. Reference numeral 3 denotes a moving body which is pressed into contact with the vibrating body 2 and forms a rotor. A plurality of electrostrictive elements l are glued together, and each electrostrictive element within the 0 group is arranged at a pitch shifted by three wavelengths of vibration and wave wavelength λ for some groups and for other groups. The elements are arranged at a pitch of the local wavelength so that the polarities of adjacent elements are i.

In a vibration wave motor with such a configuration, V is applied to one group electrostrictive element.
. An AC voltage of SinωT is applied, and an AC voltage of voCO8ωT is applied to the electrostrictive elements of the other group. Therefore, the polarities of each electrostrictive element are opposite to that of the adjacent ones, and the two groups have a 90° phase difference. A deviated AC voltage is applied, causing vibration. This vibration is transmitted and the vibrating body 2 becomes an electrostrictive element l.
bending vibration according to the arrangement pitch. When the vibrating body 2 protrudes at the position of every other electrostrictive element, the position of every other electrostrictive element retracts. On the other hand, as mentioned above, one group of electrostrictive elements has a wavelength of % relative to the other group. Bending vibration progresses due to the shifted position. 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 is shown in Figure 2 (a) (b) (c
) It is shown in (d). Now, assume that the progressive bending vibration wave advances in the direction of arrow X1. If 0 is the center plane of the vibrating body in its oldest state, then in the vibrating state it is in the state shown by the chain line, and the stress due to bending is balanced on this neutral plane 6. neutral plane 6
When looking at the cross section 71 perpendicular to , no stress is applied to the intersection line 5I of these two surfaces, and only vertical vibration occurs.

At the same time, the cross section 71 is pendulum-oscillating left and right about the intersection line 5I.

Similarly for the cross section 72 or 73, the intersection line 52 or 5
The pendulum oscillates left and right with 3 as the center.

In the state shown in FIG. 4A, a point P1 on the intersection line between the cross section 7I and the surface of the three moving bodies of the vibrating body 2 is the right dead center of left-right vibration, and the vibrating body 2 is only moving upward.

In this pendulum vibration, when the intersection line 51, 52 or 53 is on the positive side of the wave (when it is above the center plane 0), stress is applied in the left direction (opposite to the wave traveling direction X), and on the negative side of the wave ( Similarly, stress in the right direction is applied to the lower side. That is, in the same figure (a), when the intersection line 52 and the cross section 72 are in the former state, the point P
2, stress is applied in the direction of the arrow. When the intersection line 53 and the cross section 73 are in the latter state d, a stress is applied to the point P3 in the direction of the arrow.

As the wave progresses, the intersection line 51 is on the positive side of the wave as shown in (b).
When the point PI comes, it moves to the left and at the same time moves upward. In (c), point PI only moves to the left at the top dead center of the vertical vibration. In (d), point P1 moves leftward and downward. The wave further advances, moving rightward and downward, moving rightward and upward, and then returning to state (a). When this series of movements is combined, the point P1 moves in a spheroid, and the radius of rotation thereof is a function of t, where t is the length from the neutral plane 6 of the vibrating body 2 to the moving body side surface. On the other hand, the moving body 3 is in pressurized contact with the vibrating body 2, and the moving body 3 is in pressure contact with the vibrating body 2.
), the spheroidal motion of the point PI on the vibrating body 2 frictionally drives the movable body 3 in the x2 direction.

Points P2 and P3 and all other points on the vibrating body 2 are points PL
The movable body 3 is frictionally driven in the same way.

Vibration wave motors driven in this manner cannot be said to be fully satisfactory in terms of noise, drive efficiency, durability, etc.

The present invention was developed in view of this unfortunate situation, and aims to provide a vibration wave motor that is noiseless, has improved driving efficiency, and has good durability by improving the structure of a moving body. Depend on the purpose.

To achieve this object, the present invention applies a frequency and a voltage to an electrostrictive element, and uses progressive vibration waves generated in a vibrating body connected to the electrostrictive element to generate vibrations that drive a moving body in contact with the vibrating body. The vibration wave motor is characterized in that the movable body is elastically deformed and comes into contact with the vibrating body near the top of a progressive vibration wave.

The embodiments shown in the drawings will be described in detail below to clarify the structure of the present invention.

FIG. 3 shows the main part of an embodiment of a vibration wave motor to which the present invention is applied. In the figure, 3a is a part of the movable body 3, which is a thin elastic plate that comes into frictional contact with the vibrating body 2, and is made of a relatively hard and wear-resistant material such as stainless steel, titanium, duralumin, etc. 3b is an elastic material, such as a relatively soft material such as rubber. Reference numeral 3c denotes a structure of the moving body 3, which is made of metal, plastic, or the like.

The moving body 3 is in pressure contact with the vibrating body 2, and the vibrating body 2
When a progressive vibration wave is generated, the contact elastic plate 3a is elastically deformed together with the elastic substance 3b and comes into contact with the shape of the vibration wave near the top edge.

Therefore, the contact area between the movable body 3 and the vibrating body 2 is increased, and the friction drive efficiency is improved. At this time, the contact elastic plate 3
Since a is hard, even though it deforms, it does not deform to the extent that it makes contact at a position deeper than the vicinity of the apex of the vibration wave. Therefore, since it is not subjected to frictional drive in the opposite direction due to the distortion force at the bottom of the vibration wave (see FIG. 2), there is no cancellation of the driving force. Since the deformation of the movable body 3 is elastic deformation, it immediately returns to its original flat shape after passing through the contact area with the vibrating body 2.

The elastic material 3b of the moving body 3 also serves as a dashpot that absorbs 1# of vibration. It is not possible to suppress the jump of the moving body 3 that occurs when the amplitude of the vibration wave fluctuates, so uneven rotation and noise are less likely to occur, and the output does not decrease.

Note that the contact elastic plate 3a can be surface-treated by plating, sputtering, ion implantation, etc. to improve wear resistance and increase the coefficient of friction. In addition, the elastic material 3b may be made of a porous material such as a sponge other than rubber, and the porous material may be impregnated with a liquid such as oil. If this is done, the effect of the dashpot will be even greater. The elastic material 3b serving as a cushioning material is rubber,
A laminated structure of porous materials may also be used. In these cases, the spring constant and damping coefficient of the elastic material 3b are determined by taking into consideration various conditions such as the frequency and amplitude of the vibration wave, and the contact pressure of the moving body 3 with respect to the vibrating body 2. design.

As shown in Fig. 4, even if a material 3b with a lower elastic modulus is attached to the moving body structure 3C, which has a somewhat higher elastic modulus, to a thickness that is equal to or less than the amplitude of the vibration wave, the same effect can be obtained. is obtained.

As described above, according to the present invention, it is possible to obtain a vibration wave motor that is free from noise, has improved driving efficiency, and has good durability.

It should be noted that the present invention can be applied not only to the rotary type vibration wave motor shown in the embodiments but also to a linear type vibration wave motor.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the main parts of a vibration wave motor, FIG. 2 is a diagram explaining the driving principle of the vibration wave motor, and FIG. 3 is a schematic diagram of the main parts of an embodiment of a vibration wave motor to which the present invention is applied. FIG. 4 is a schematic diagram of main parts of another embodiment. 1 is an electrostrictive element, 2 is a vibrating body, 3 is a moving body, 3a is a contact elastic plate, 3b is an elastic material, and 3C is a structure of the moving body. Figure 2 Figure 1 Figure 3 Figure 4 (1) Procedure auxiliary device March 29, 1985 Patent application No. 14905 2, Title of invention Vibration wave motor 3, Case of person making amendment Relationship with Patent Applicant Name (100) Canon Co., Ltd. 4, Agent Kimura Building 5, 1-12 Yoyogi 2-chome, Shibuya-ku, Tokyo Subject of amendment Specification “Claims” / “Details of the invention "Explanation" column. (2) Lines 12-13 of page 5 of the specification shall be amended as follows. Vibration wave mode characterized in that the recording body is supported by an elastic body impregnated with liquid (3) The second line from the bottom of page 6, ``It also plays a role.'' is amended as follows. A porous material (such as a sponge) is impregnated with a liquid such as oil to serve as a recorder. Dashpots become extremely effective when impregnated with liquid. (0 same page 7 lines 6-8 “Also 1 elastic substance 3b...
・Delete "It may be impregnated." 2. Claims (1) A vibration wave motor that applies a frequency voltage to an electrostrictive element and drives a moving body in contact with the vibrating body using progressive vibration waves generated in a vibrating body joined to the electrostrictive element. 2. A vibration wave motor characterized in that the movable body has a vibration wave caused by the vibration.

Claims (1)

[Claims] (1) In a vibration wave motor that applies a frequency voltage to an electrostrictive element and drives a moving body in contact with the vibrating body by progressive vibration waves generated in a vibrating body joined to the electrostrictive element. A vibration wave motor characterized in that the movable body is elastically deformed and comes into contact with a vicinity of a top edge of a progressive vibration wave of the vibrating body.