JPH01243861A - Oscillatory wave motor - Google Patents

Abstract

PURPOSE:To decrease the distortion of an oscillation absorber, by dividing said oscillation absorber such as rubber to be provided on the mover side into small parts and by providing said absorber with a plurality of notches. CONSTITUTION:An oscillatory wave motor is composed of an elastic body 1, a piezoelectric element 2, a flexible printed-circuit board 3, a oscillation isolator 4, a pressuring disc spring 5, a rotor 6, a felt-fixing stand 7, a pressurizing and regulating spacer 8, a whirl-stop 9, a fixed tube 10, an absorber 11, an output connecting plate 12, a ball bearing inner ring and output tube 13 and others. Said absorber 11 has divided parts 11a to reduce a distortion by thermal expansion. Also, said piezoelectric element 2 is polarized according to the pattern of its electrodes 2a-2b to adhere to the elastic body 1 and two frequency voltages are applied through the flexible printed-circuit board 3 from the outside so that a progressive wave is generated in said elastic body 1. Said rotor 6 is friction-driven by said progressive wave. Thus, the oscillation absorber 11 absorbs the portion of oscillation, which cannot be completely absorbed by the rotor 6, to transmit the rotation of said rotor 6.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a vibration wave motor that drives a moving body by progressive vibration waves generated on a vibrating body. It relates to the structure of a vibration absorber that absorbs and damps vibrations.

[Prior Art] A vibration wave motor, also called an ultrasonic motor, applies a frequency voltage to a piezoelectric element on a vibrating body to generate progressive vibration waves on the vibrating body, and drives a moving body with the vibration waves. Compared to conventional electromagnetic motors, it does not require windings.
It has been attracting attention in recent years because it has the advantage of being small and being able to obtain high torque even when rotating at low speeds.

As a means for exciting the vibrating body of the vibration wave motor, an electro-mechanical energy conversion element, such as a piezoelectric element, an electrostrictive element, or a magnetostrictive element, which periodically deforms according to the applied frequency voltage may be used.

By the way, this kind of traveling wave type vibration wave motor can be easily realized in a hollow ring shape, so it is used as a focusing actuator and a yuator for lenses for reflex cameras. At this time, in order to absorb the vibrations of several micrometers generated by the vibration wave motor, instead of increasing the overall size and increasing the rigidity, as shown in Figure 4, a simple ring-shaped vibration absorber made of rubber or the like is used. The body 21 is used to achieve miniaturization.

However, since the members constituting the vibration wave motor are mainly made of metal, there is a large difference in coefficient of thermal expansion from the vibration absorber 21 made of rubber or the like, which causes distortion.

Now, the rotor which is a moving body is An, the vibration absorber 21 is butyl rubber, the output connecting plate is Bs, and the center diameter is 72.25 m +
When n is the case, the amount of deformation and the strain generated in the vibration absorber 21 at each temperature in the radial direction from the case where the normal temperature is 23° C. are as shown in Table 1.

Note that if the thickness of the vibration absorber 21 is approximately 1 non, then 2 to 3
Thickness unevenness occurs due to distortion of μm, which is a non-negligible amount for a traveling wave amplitude of several μm.

[Problems to be Solved by the Invention] As mentioned above, in the conventional technology, the members constituting the vibration wave motor are mainly metal, and the vibration absorber 21 made of rubber or the like has a simple ring shape. Due to changes in the environmental temperature, there is a large difference in the coefficient of thermal expansion between the vibration absorber 21 and the vibration absorber 21. As a result, as shown in Table 1 above, distortion occurs in the vibration absorber. There is a problem in that it has an adverse effect and, in turn, increases the generation of vibration and sound.

The present invention attempts to solve these problems. That is, the present invention reduces the distortion of the vibration absorber caused by the difference in thermal expansion coefficient due to environmental temperature changes, and
The object of the present invention is to provide a vibration wave motor that does not generate vibration or sound.

[Means for Solving the Problems] In order to achieve the above objects, the present invention provides a pair of electro-mechanical energy converting elements comprising an A phase and a B phase arranged or polarized in a phase-differential manner. A first standing wave generated by applying a first frequency voltage to the A phase of the group and a second standing wave that is out of phase by a predetermined amount from the first frequency voltage to the B phase.
A vibration wave motor having a vibrating body that generates a progressive vibration wave by combining with a second standing wave generated by applying a frequency voltage of , and a moving body frictionally driven by the progressive vibration wave. A vibration absorber made of rubber or the like that absorbs and damps unnecessary vibrations of the moving body is interposed between the fixed bodies, and the vibration absorber is finely divided or has a structure having a plurality of notches.

[Function] According to the present invention, the vibration absorber made of rubber or the like provided on the moving body side is finely divided or has a plurality of notches, so that the vibration absorber is not affected by differences in thermal expansion coefficient due to environmental temperature changes. Distortion is reduced, and vibration and sound generation due to temperature changes are eliminated.

[Example code] FIG. 1 shows a first embodiment of the invention.

In FIG. 1, 1 is an elastic body made of metal, and 2 is an electric body.
A piezoelectric element as a mechanical energy conversion element, 3 a flexible printed circuit board, 4 a vibration insulator mainly made of felt, 5 a disc spring for pressure, 6 a rotor as a moving body mainly made of metal, and 7 a felt. A fixing table, 8 a spacer for pressure adjustment, 9 a rotation stopper for the elastic body 1, 10 a fixed cylinder, 11 a vibration absorber made of rubber or the like, 12 an output connecting plate, and 13 a ball. Bearing inner ring/output cylinder, 14 is a holding ring, 1
5 is a ball bearing outer ring, 16 is a ball, 17, 18, 19 are fixing screws, and 20 is a fixing base.

The operating principle and basic structure of the vibration wave motor shown in FIG. 1 are almost the same as those described in Japanese Patent Laid-Open No. 62-21358.

First, the piezoelectric element 2 is polarized according to the pattern of the electrodes 8i2a and 2b on both sides, and is bonded to the elastic body 1.

The piezoelectric element 2 is externally connected to the piezoelectric element 2 through a flexible printed circuit board 3 with a phase shift of ±9
When two frequency voltages (0°) are applied, a traveling wave of several micrometers due to bending vibration is generated in the elastic body 1 due to resonance. The elastic body 1 has a trapezoidal cross section and a plurality of comb-like contact portions 1b in order to improve efficiency.

The rotor 6 contacts the elastic body 1 via the wear-resistant material 1a and is frictionally driven according to the traveling wave. Further, the rotor 6 is formed with a flange-shaped spring portion 6a that follows a traveling wave of several micrometers and absorbs vibrations.

The vibration absorber 11 absorbs vibrations in parts of the rotor 6 that cannot be completely absorbed, and also transmits the rotation of the rotor 6. The rotation of the rotor 6 is controlled by the screw 1 via the output connecting plate 12.
It can be taken out as an output from the output cylinder 13 fixed at 8.

The output tube 13 also serves as an inner ring of a ball bearing, and the ball 16, outer ring 15, and presser ring 14 constitute the bearing.

The elastic body 1 is held by a vibration insulator 4 such as felt fixed to a stand 7 to insulate vibrations. Further, the table 7 is pressurized by a pressure plate spring 5, the frictional force between the rotor 6 and the elastic body 1 is adjusted by a spacer 8, and the fixed table 20 is fixed to the fixed cylinder 1o with screws 19.

Since the elastic body 1 may be damaged by the reaction of the rotor 6, it is engaged with the rotation stopper 9 using the comb-shaped grooves 1b to prevent it from rotating, and is fixed to the fixed cylinder 10 with screws 17. ing.

FIG. 2 shows an enlarged view of the vibration absorber 11 shown in FIG. This vibration absorber 11 has a divided portion 11a, that is, is divided into a large number of parts in the circumferential direction, and has the effect of significantly reducing the distortion due to thermal expansion shown in Table 1 above.

FIG. 3 shows a second embodiment of the present invention, in which only the vibration absorber 11 is shown.

In this second embodiment, the vibration absorber 11 is provided with a large number of inner cuts llb and a large number of outer cuts 1c alternately in the circumferential direction. In this case as well, the strain caused by thermal expansion is absorbed by these cuts lb and lc, which has the same effect as in the case of Fig. 2, and since it is not divided, it can be made in one piece and is easy to handle. It's simple.

[Effects of the Invention] As explained above, according to the vibration wave motor of the present invention,
By dividing the vibration absorber into smaller pieces or by making multiple cuts, it is possible to significantly reduce distortion caused by thermal expansion caused by temperature changes, which in turn has the effect of suppressing vibrations and noise caused by temperature changes.

[Brief explanation of the drawing]

Fig. 1 is a partial sectional view showing the first embodiment of the present invention;
The figure is an enlarged plan view of the vibration absorber shown in FIG. 1, FIG. 3 is an enlarged plan view of the second embodiment of the present invention showing only the vibration absorber, and FIG. 4 is an enlarged plan view showing the conventional vibration absorber. be. 1... Elastic body 2... Piezoelectric element 4... Vibration insulator 5... Pressure disc spring 6... Rotor
1o... Fixed tube 11... Vibration absorber 1
2...Output connection board 1) Positive line spacing. d lung

Claims (2)

[Claims] 1. Applying a first frequency voltage to the A phase of a pair of electro-mechanical energy conversion element groups consisting of an A phase and a B phase, which are either arranged phase-differentially or polarized. A first standing wave generated by applying a voltage to the B phase and a second frequency voltage whose phase is shifted by a predetermined amount from the first frequency voltage.
a vibrating body that generates a progressive vibration wave by combining with a second standing wave generated by applying a frequency voltage of
Further, in a vibration wave motor including a moving body that is frictionally driven by the progressive vibration waves, a vibration absorber that absorbs and damps unnecessary vibrations of the moving body is interposed between the fixed bodies, and the vibration absorber is A vibration wave motor characterized by being made up of finely divided parts. 2. Applying a first frequency voltage to the A phase of a pair of electro-mechanical energy conversion element groups consisting of an A phase and a B phase, which are either arranged phase-differentially or polarized. A first standing wave generated by applying a voltage to the B phase and a second frequency voltage whose phase is shifted by a predetermined amount from the first frequency voltage.
a vibrating body that generates a progressive vibration wave by combining with a second standing wave generated by applying a frequency voltage of
Further, in a vibration wave motor including a moving body that is frictionally driven by the progressive vibration waves, a vibration absorber that absorbs and damps unnecessary vibrations of the moving body is interposed between the fixed bodies, and the vibration absorber is A vibration wave motor comprising a plurality of notches.