JPH0279783A - Ultrasonic wave motor - Google Patents

Abstract

PURPOSE:To prevent attenuation of wave motion and to improve efficiency by movably coupling the tips of supporting members into the recess parts at the side surfaces of an annular stator which generates a travelling wave or a standing wave and rotates a rotor, and supporting said tips. CONSTITUTION:Both sides of an annular piezoelectric body 6 are held with annular elastic bodies 7 and 8, and a stator 1 is formed. The piezoelectric body 6 is divided into a plurality of regions in the circumferential direction. The polarities of the regions in the plate-thickness direction are alternately reversed. Two electrodes are provided on one surface of the piezoelectric body 6 with non-electrode parts having the lengths of lambda/4 and 3lambda/4 (lambda is the length of a resonating wave) being provided. A rotors 2 are compressed to both surfaces of the stator 1 through friction materials 13. In a supporting member 4, an end part 17 is attached to a guide member 16 for a shaft 3. An end part 19 of a supporting member 5 is attached to a casing 14. A pin 18 of the end part 17 and a pin 20 of the end part 19 are movably coupled into recess parts 11 and 12 formed on the side surfaces of the stator. Thus the end parts are supported. In this way, the attenuation of vibration generated in the stator is prevented, and the efficiency and the torque of the motor are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic motor, and particularly to an ultrasonic motor with an improved stator support structure.

[Summary of the invention]

The invention according to claim (1) provides an ultrasonic motor in which a stator is supported by a support member, in which a side surface of a stake having an annular shape and an end portion of the support member corresponding to the side surface of the stator By forming a pin on one side and a recess slightly larger than the pin on the other side, and supporting the stator by engaging the pin in the recess, the traveling waves or standing waves generated in the stator during driving can be reduced. The displacement of the stator can be absorbed without affecting the waves, and the attenuation of traveling waves or standing waves can be prevented.

The invention according to claim (2) provides an ultrasonic motor in which the stator is supported by a support member, wherein the stator has a substantially four-ring shape, and a tongue piece is provided on at least one of both sides of the ultrasonic motor. By supporting the stator by sandwiching the tongue piece between the supporting members, displacement of the stator can be absorbed without affecting the traveling waves or standing waves generated in the stator during driving. It is designed to prevent attenuation of waves or standing waves.

[Conventional technology]

A traveling wave ultrasonic motor has a piezoelectric element that is annular and selectively polarized, generates a traveling wave in an elastic body attached to one side of the piezoelectric element, and is pressed against this elastic body. There is a type that rotates a rotor.

An example of an ultrasonic motor with such a traveling waveform is disclosed in Japanese Patent Application Laid-open No. 62
It is disclosed in Japanese Patent Application Laid-Open No. 61-277384.

[Problem to be solved by the invention]

The support of the stator in the conventional ultrasonic motor as described above is described, for example, in Japanese Patent Application Laid-Open No. 61-277384.
The elastic body of the stator was directly fixed to the case by a fixed plate for supporting the stator. Further, in Japanese Patent Application Laid-Open No. 62-100179, a plurality of fixing pieces are interposed between the case and the stator to fix the stator to the case.

In such conventional technology, since the stator is fixedly supported with respect to the case, there is a problem in that the displacement of the stator caused by the traveling wave cannot be absorbed without affecting the traveling wave. For this reason, there is a problem in that the traveling waves generated in the stator propagate to a member such as the case along with the displacement of the stator, and as a result, the traveling waves are attenuated. Additionally, if only one of the outer and inner circumferential sides of the annular stator is fixed, there may be a change in the traveling wave or standing wave between the outer and inner circumferential sides of the stator. Yes, in such cases,
There is a problem in that noise-like waves and unnecessary waves are generated and the traveling waves are further attenuated.

Furthermore, since the traveling wave is attenuated, there is a problem in that the efficiency and torque of the ultrasonic motor are reduced.

Such problems occur not only in progressive waveform ultrasonic motors but also in standing waveform ultrasonic motors.

Therefore, an object of the present invention is to provide an ultrasonic motor that can prevent traveling waves or standing waves from propagating to areas other than the stator.

[Means to solve the problem]

According to the invention of claim (1), in an ultrasonic motor that rotates a rotor by a traveling wave or a standing wave generated by a stator supported by a support member, a side surface of the stator having an annular shape; A configuration in which a pin is formed on one side of the end of the support member corresponding to the side surface of the support member, and a recessed portion slightly larger than the pin is formed on the other side, and the pin is engaged with the recessed portion to support the stator. It is said that

In the invention of claim (2), in an ultrasonic motor that rotates a rotor by a traveling wave or a standing wave generated by a stator supported by a support member, the stator has a substantially annular shape, A tongue piece is formed on at least one of the two side faces, and the tongue piece is held between supporting members to support the stator.

[Effect]

Claim (1)--1-- Since there is a gap, or so-called play, between the pin and the recess, when the ultrasonic motor is driven,
Displacement of the stator can be absorbed without affecting the traveling waves or standing waves generated in the stator.

Claim (2): Since the tongue piece extending from the stator is held, it does not affect the traveling waves or standing waves generated in the stator when the ultrasonic motor is driven. can absorb the displacement of the stator.

Therefore, the traveling waves or standing waves generated in the stator are prevented from propagating to the supporting member of the stator, and the attenuation of the traveling waves or standing waves is prevented.

In addition, there is no change in the traveling waves or standing waves between the outer circumferential side and the inner circumferential side of the annular stator, and no unnecessary waves are generated. Therefore, attenuation of the traveling waves and standing waves is further prevented. Ru. Furthermore, efficiency and torque are improved.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to a traveling wave type ultrasonic motor as shown in FIGS. 1 to 9. Note that this embodiment will be explained in the following order.

(A) First embodiment (B) Second embodiment (C) Modification of the second embodiment (D) Third embodiment (E) Fourth embodiment (A) First embodiment FIG. A cross-sectional view of an ultrasonic motor that utilizes traveling waves on both the upper and lower sides of a stator is shown. This ultrasonic motor includes a stator l, a rotor 2, a shaft 3, and a support member 4.5.
It mainly consists of.

In the stator 1, alternating current voltages having different phases are applied to the piezoelectric body 6, thereby causing bending vibration in the elastic body 7.8 and generating traveling waves. The stator 1 has a three-layer structure. That is, it is constructed by disposing the piezoelectric body 6 between the upper and lower elastic bodies 7 and 8. In the inner surface 9 and outer surface 10 of the stator 1, recesses 11 and 12 for inserting inner pins and outer pins, which will be described later, are larger in size than the inner pins and outer pins, and are arranged in a direction perpendicular to the plane of the paper in FIG. A plurality of them are formed continuously or discontinuously.

The piezoelectric body 6 has an annular shape as a whole and is arranged between the elastic bodies 7 and 8. This piezoelectric body 6 consists of a piezoelectric element and an electrode. Although not shown, the piezoelectric element is divided into a plurality of regions in the circumferential direction, and the polarity of each region is alternately reversed in the thickness direction. Further, two electrodes are provided on one surface of the piezoelectric element, and these electrodes are provided with a non-electrode portion having a length of λ/4.3λ/4 (λ is the resonant wavelength) separated from each other.

The rotor 2 is pressed against the stator 1 by a biasing means (not shown) in order to generate a frictional force between the rotor 2 and the stator 1. When a traveling wave is generated in the stator 1, the stator 1 rotates due to the frictional force generated between the stator 1 and the stator 1. The rotors 2 are arranged on both upper and lower sides of the stator 1, respectively. Note that 13 indicates felt.

The shaft 3 transmits the driving force obtained by the rotation of the rotor 2.

The support member 4.5 supports the stator 1 in a predetermined position. The support member 4 is attached to the shaft 3 on the inner peripheral side of the stator 1.
is fixedly supported. This support member 4 has a guide portion 16 for shaft insertion around the shaft 3, and this guide portion 1
An inner pin 18 is formed at an end portion 17 extending from 6 toward the inner surface 9 of the stator 1 . The support member 5 is inserted through the insertion hole 15 of the casing 14 and is detachably attached to the recess 12 on the outer circumferential side of the stator l. An outer pin 20 is formed on the support member 5 at an end 19 on the side corresponding to the outer surface 10 of the stator 1 .

The stator l is supported in the following manner.

As shown in FIGS. 1 and 2, the inner pin 18 of the support member 4 is inserted into the recess 11 of the stator 1, and
The outer surface l of the stator 1 corresponding to the position of the inner pin 18
The outer pin 20 is inserted into the recess 12 of the casing 14 through the insertion hole 15 of the casing 14. Note that this support by the inner pin 18 and the outer pin 20 is performed at a plurality of locations. Therefore,
The stator l is loosely supported in a predetermined position by inserting the inner pin 18 and the outer pin 20 into the recesses 11 and 12, respectively.

A slight gap, or so-called "play", is provided between the recess 11, 12 of the stator 1, the inner pin 18, and the outer pin 20, respectively, so that the degree of freedom for changing the position of the stator l is increased. .

In this way, the stator 1 is loosely supported by the inner pin 18 and the outer pin 20 with some play, so that the displacement of the stator 1 can be controlled without affecting the traveling waves generated in the stator 1 during driving. Can absorb [displacement due to bending vibration]. This can prevent the traveling wave from propagating to the support member 4.5, and can prevent the traveling wave from being attenuated. In addition, since changes in traveling waves are prevented between the inner and outer circumferential sides of the stator 1, noisy waves,
Generation of so-called unnecessary waves can be prevented, and attenuation of traveling waves can be further prevented. In addition, the efficiency and torque of the ultrasonic motor can be improved.

In this first embodiment, for example, the inner bin 18 is formed on the support member 4 side and the recess 11 is formed on the stator 1 side, but the recess is formed on the support member 4 side and the inner pin is formed on the stator 1 side. Alternatively, the stator 1 may be connected to the inner pin 18,
Although supported by the outer bin 20, the present invention is not limited to this, and only one side may be supported by the bin. This is particularly effective in a type of ultrasonic motor that uses traveling waves on both the upper and lower sides of the stator l. Furthermore, in this embodiment, an ultrasonic motor with a traveling waveform is used as an example, but the present invention is not limited to this (it is also fully applicable to an ultrasonic motor with a bending standing waveform). be.

(B) Second Embodiment FIG. 3 shows a partial cross-sectional view of the stator 31.
The figure shows the state of insertion of the outer pin.

This second embodiment differs from the first embodiment in that the recesses 32 and 33 of the stator 31 are provided on the inner and outer surfaces 35 and 36 of the elastic body 34, and that the rotor 2 is located above the stator 31. The piezoelectric body 6 is disposed only on the lower surface of the elastic body 34. And 37 is the inner pin, 3
8 indicates the outer pins, respectively.

The other contents are the same as those in the first embodiment, so redundant explanation will be omitted.

(C) Modification of the second embodiment In FIG. 5, the outer pin 3 is
A partial cross-sectional view of 8 inserted is shown in FIG.
The condition of the outer bottle 3 days of insertion is shown.

The modification shown in FIG. 5 differs from the second embodiment in that the outer pin 38 is inserted into the recess 33 of the stator 31 via an elastic damper 40 made of synthetic resin, rubber, etc. . Due to the intervention of this damper 40, the stator 3
1 and the outer pin 38 do not come into direct contact with each other, thereby more effectively absorbing displacement of the stator 31 and preventing attenuation of the traveling wave.

The modification shown in FIG. 6 differs from the second embodiment in that the outer pin 38 is made of metal and has a circular cross-section, and the outer pin 38 is inserted into the recess 33 of the stator 31.
It is inserted through the damper 4o mentioned above.

In the examples of FIGS. 5 and 6, the recess 33 and the outer pin 38 are described, but of course a similar structure may be provided between the recess 32 and the inner pin 37. Further, although this modification is described as a modification to the second embodiment, it may also be applied to the first embodiment.

Regarding other contents in both Figures 5 and 6, please refer to the above 1.
, is the same as the second embodiment, so redundant explanation will be omitted.

(D) Third Embodiment FIG. 7 shows a partial sectional view of the stator 31.

This third embodiment differs from the second embodiment in that the tongue pieces 51 and 52 formed at the lower part of the elastic body 34 are fixed to the first support member 53 and the second support member 54 as support members. It is loosely held between members 55 and 56 and bolts 57.

As shown in FIG. 7, both the first and second support members 53.
The tip portions 58.5° 9 of 54 are all formed thin. A threaded portion 60 for fastening the bolt 57 is formed at the tip end portions 58 and 59.

The fixing members 55, 56 are attached to the tip portions 58, 59 by bolts 57 while being in loose contact with the tongues 51, 52 mentioned above.
A bolt hole 61 for inserting a bolt is formed in a portion corresponding to the threaded portion 6°.

The stator 31 is supported in the following manner.

The above-mentioned tongues 51, 52 are positioned and placed on the tips 58, 59 of both the first and second support members 53, 54, respectively. The fixing member 55.56 is then positioned over the tongue 51.52. Then, the bolt hole 6 of the fixing member 55, 56
1 and the threaded portions 60 of the tip portions 58 and 59 are aligned, and then loosely screwed together and fixed with bolts 57.

Similarly, the fixing members 55, 56 and the plurality of fixing portions set at the distal ends 58, 59 of both the first and second support members 53, 54 are screwed together and fixed by bolts 57, respectively.

Thereby, the tongue pieces 51.52 of the stator 31 are held between the tip portions 58.59 and the fixing members 55.56, and the stator 31 is supported in a predetermined position. In the description of this embodiment, it is assumed that the tongue pieces 51 and 52 are clamped by the bolt 57, but the present invention is not limited to this, and any clamping means can be selected, such as a spring, for example.

The other contents are the same as in the second embodiment, so the same parts are designated by the same reference numerals, and redundant explanation will be omitted.

(E) Fourth Embodiment FIG. 8 shows a sectional view of the stator 31, FIG. 9 shows a plan view of the stator 31 and the fixing member 71, and
The figure shows a cross-sectional view of the tongue piece 51 being held between the elastic members.

This fourth embodiment differs from the third embodiment in that only the tongue piece 51 on one side is gently held and fixed by the first support member 53, bolt 57, and fixing member 71, and The member 71 is configured to be able to clamp the tongue piece 51 via a damper 72 made of synthetic resin, rubber, or the like.

As shown in FIG. 8, the tip 5 of the first support member 53
8 is formed thin and has a bolt hole 73 for bolt insertion. The fixing member 71 has one end in contact with the tongue piece 51, and the other end is adapted to respond to changes in the distance Ll on the one end side by a spring (not shown) or the like.For example, as shown in FIG. When the tongue piece 51 is fixed at one end via the damper 72, the spacing L1 corresponding to the thickness of the other end is similarly maintained at the other end. Further, a bolt hole 74 for inserting a bolt is formed on the above-mentioned one end side.

The stator 31 is supported in the following manner.

The tongue piece 51 of the stator 31 is positioned and placed on the tip end 58 of the first support member 53. Next, position the fixing member 71 (damper 72 is added if necessary) on top of this tongue piece 51, align the bolt holes 73 and 74,
Loosely screw together and fix with bolts 57 and nuts 75.

Similarly, as shown in FIG.
and a plurality of fixed portions of the first support member 53 are loosely screwed together and fixed using bolts 57 and nuts 75.

The other contents are the same as those in the third embodiment, so the same parts are denoted by the same reference numerals, and redundant explanation will be omitted.

〔Effect of the invention〕

According to the invention of claim (1), since there is a gap, or so-called play, between the pin and the recess, when the ultrasonic motor is driven, the traveling wave can be generated without affecting the traveling wave or standing wave generated in the stator. Alternatively, there is an effect that displacement of the stator due to standing waves can be absorbed.

Further, according to the invention of claim (2), since the tongue piece extending from the stator is held, the traveling wave or standing wave generated in the stator is not affected when the ultrasonic motor is driven. This has the effect of absorbing displacement of the stator due to traveling waves or standing waves.

Due to the above-mentioned effects, both claims (1) and (2) claim that the traveling waves or standing waves generated in the stator can be prevented from propagating to parts other than the stator, and the attenuation of the traveling waves or standing waves can be prevented. effective.

Furthermore, since there is no change in the traveling waves or standing waves between the outer and inner circumferential sides of the annular stator, no unnecessary waves are generated and attenuation of the traveling waves or standing waves is further prevented. effective. This also has the effect of improving the efficiency and torque of the ultrasonic motor.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged sectional view showing a first embodiment of the invention;
2 is a schematic perspective view for explaining the first embodiment, FIG. 3 is a partially enlarged sectional view showing the second embodiment, FIG. 4 is a schematic perspective view for explaining the second embodiment, and FIG. 5 is a partially enlarged sectional view showing a modification, FIG. 6 is a schematic perspective view for explaining the modification, FIG. 7 is a partially enlarged sectional view showing the third embodiment, and FIG. 8 is a fourth embodiment. FIG. 9 is a plan view taken from the direction indicated by the arrow (■) in FIG. 8, and FIG. 10 is a partially enlarged sectional view for explaining the fourth embodiment. Explanation of main symbols in the drawings 1.31: Stator, 2: Rotor, 4.5: Support member,
9.35: Inside surface, 10.36: Outside surface, 11.12.
32.33: recess, 17.19: end, 18.37: inner bin, 20.38: outer bin, 51.52: tongue piece, 5
3: first support member, 54: second support member, 55.56:
Fixed member, 57: bolt. Agent Patent Attorney Masatoshi Sugiura

Claims (2)

[Claims] (1) In an ultrasonic motor that rotates a rotor by a traveling wave or a standing wave generated by a stator supported by a support member, the side surface of the annular stator corresponds to the side surface of the stator. A pin is formed on one end of the support member, and a recess slightly larger than the pin is formed on the other end, and the pin is engaged with the recess to support the stator. An ultrasonic motor characterized by: (2) In an ultrasonic motor in which the rotor is rotated by a traveling wave or a standing wave generated by a stator supported by a support member, the stator has a substantially annular shape, and on both sides thereof,
An ultrasonic motor characterized in that a tongue piece is formed on at least one side surface, and the stator is supported by sandwiching the tongue piece between the support members.