JPH11252952A - Ultrasonic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly control the rotation of a rotor without fail when both a stator and the rotor are provided with a piezoelectric vibrator. SOLUTION: Piezoelectric vibrators 5v, 6v are made of one and the same material and formed into one and the same shape, and at least the vibrating portions of elastic bodies 5e, 6e used for driving are made of one and the same material and formed into one and the same shape. The numbers of natural oscillations of oscillating bodies 5g, 6g comprising the piezoelectric vibrators 5v, 6v and at least the vibrating portions of the elastic bodies 5e, 6e used for driving are match with each other. When the piezoelectric vibrators 5v, 6v are supplied with a signal of the resonance frequency of the oscillating bodies 5g, 6g or a frequency close to the resonance frequency in this state, traveling waves produced at the pressure-welded faces can be method with each other. As a result, the rotation of the rotor 6 can be properly controlled properly by continuously shifting the engaging lock position of the traveling waves. In addition, since both the numbers of natural oscillations are shifted in the same direction by the same amount, the engaging lock of the traveling wave will not release and the rotation of the rotor 6 can be controlled properly without fail, even of the numbers of natural oscillations of the oscillating bodies 5g, 6g are shifted due to effects of temperature, humidity, load or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an ultrasonic motor.

[0002]

2. Description of the Related Art Conventional general ultrasonic motors include:
An elastic body and a stator (stator) composed of a piezoelectric element (vibrator) provided on the elastic body; and a rotor (rotor) opposed to and pressed against the elastic body. It is known that a signal of a predetermined frequency is supplied to vibrate the piezoelectric element to generate a traveling wave on a pressing surface of the elastic body, and the traveling wave rotates a rotor.

For example, Japanese Patent Laid-Open Publication No. Hei 2-179281 discloses that the rotor is composed of an elastic body and a piezoelectric element provided on the elastic body. By supplying a signal of a predetermined frequency to both the rotor-side piezoelectric element and the rotor-side piezoelectric element, both the piezoelectric elements are vibrated to generate traveling waves on the pressure contact surfaces of both the stator-side elastic body and the rotor-side elastic body. An ultrasonic motor that drives the rotor to rotate by both traveling waves is disclosed.

[0004]

However, in an ultrasonic motor that vibrates both a stator and a rotor, such as the ultrasonic motor described in Japanese Patent Application Laid-Open No. 2-179281, the configuration described in the publication alone is not sufficient. , It is difficult to obtain a good rotation operation.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and in an ultrasonic motor having a vibrator on both a stator and a rotor, the rotor can be controlled to rotate well. It is another object of the present invention to provide an ultrasonic motor capable of reducing costs.

[0006]

SUMMARY OF THE INVENTION An ultrasonic motor according to the present invention comprises a fixed-side elastic member and a fixed-side vibrator provided on the fixed-side elastic member; A movable-side elastic body and a rotor composed of a movable-side vibrator provided on the movable-side elastic body, and a signal of a predetermined frequency is supplied to each of the two vibrators. In the ultrasonic motor that drives the rotor by a traveling wave generated on the press-contact surface of each elastic body in response to the vibration, the two vibrators are made of the same material and have the same shape. The body is characterized in that at least the vibrating portions to be driven are made of the same material and have the same shape.

According to the ultrasonic motor of the present invention, at least the vibrating portion and both vibrators for driving both elastic members are made of the same material and have the same shape. The natural frequencies of the vibrating body composed of at least the vibrating part used for driving are matched. Therefore, when signals of the resonance frequency of the vibrator or a frequency in the vicinity thereof are supplied to the two vibrators, the traveling waves generated on the press contact surfaces of the two elastic bodies are locked (matched) as if the gears meshed. When the rotor is stopped, and the phase of one signal is shifted positively or negatively with respect to the other, the meshing lock position shifts in the forward direction or the reverse direction. The child rotates forward or reverse. That is, by employing the above configuration, the rotation of the rotor can be favorably controlled.

Further, since at least the vibrating portion and both vibrators used for driving the two elastic members are made of the same material and have the same shape, the parts are shared,
Cost reduction is achieved.

Here, the natural frequency of the vibrating body is shifted by the influence of temperature, humidity, load, applied pressure, drive power, and the like. Although there is a possibility that the engagement lock of the traveling wave may be broken, as described above, at least the vibrating portion and both vibrators provided for driving the two elastic bodies are made of the same material and have the same shape. , The two natural frequencies are shifted by the same amount in the same direction. That is,
The engagement lock of the traveling wave does not break down, and the rotation of the rotor can always be controlled well.

Preferably, the two elastic bodies are made of the same material and have the same shape. When such a configuration is adopted, the natural frequencies of the stator and the rotor as a whole match, so that the rotation of the rotor can be controlled even better. Further, since the number of parts of the stator and the rotor is minimized and the parts are shared, the cost can be further reduced.

Each of the elastic members includes a member provided with a vibrator and pressed against another opposing elastic member, and at least one other member other than the member.
It is preferable that the members corresponding to the fixed-side and movable-side elastic bodies are made of the same material and have the same shape.
When such a configuration is adopted, even if the shape accuracy of the other member is roughened compared to the shape accuracy of one member, that is, at least the shape accuracy of the vibrating portion used for driving the elastic body, the pressure contact surface Of the traveling wave is hardly affected. Therefore, the manufacturing cost can be reduced because the shape accuracy of the other members can be roughened.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an ultrasonic motor according to the present invention will be described below with reference to the accompanying drawings. In the description of the drawings, the same elements or elements having the same functions will be denoted by the same reference symbols, without redundant description.

FIG. 1 is a cross-sectional view showing an ultrasonic motor according to the first embodiment. The ultrasonic motor includes an ultrasonic motor main body 1 including a mechanical drive mechanism and an electric control unit 2 that drives the ultrasonic motor main body 1.

The ultrasonic motor main body 1 includes a fixing base 3 fixed to a fixed side of a main body device such as a camera to which the ultrasonic motor is applied, and a circular outer edge fixed on the fixing base 3 in an overlapping manner. A stator 5, a rotating base 4 which is inserted through the fixing base 3 and a central portion of the stator 5 and is rotatably supported by a bearing 7 fixed to the stator 5, and an outer peripheral circle press-fitted and fixed to the rotating shaft 4. And the rotor 6.

The rotor 6 shifts the phase of one traveling wave positively or negatively with respect to the other while the traveling waves generated in the circumferential direction of the opposing contact surfaces of the stator 5 and the rotor 6 mesh with each other. Then, the meshing position is shifted in the normal rotation direction or the reverse rotation direction, and the meshing position is rotated forward or reverse according to the continuation of the shift amount (details will be described later).

The stator 5 includes an annular vibrator 5v made of a ceramic piezoelectric element, and an annular elastic body 5e made of a metal with the vibrator 5v adhered to the outer periphery of the back surface (the lower surface in the figure). ing. The outer peripheral portion 5o and the inner peripheral portion 5i of the elastic body 5e are thick, and the vibrator 5v is attached to the back surface of the outer peripheral portion 5o, and the inner peripheral portion 5i is fixed to the fixing base 3 by, for example, screwing. Is done. The annular intermediate portion 5m between the outer peripheral portion 5o and the inner peripheral portion 5i of the elastic body 5e is thin, and the intermediate portion 5m facilitates the vibration of the outer peripheral portion 5o, and the outer peripheral portion 5o and the inner peripheral portion. 5i is suppressed.

In particular, in the present embodiment, the rotor 6 is
A rotor-side vibrator 6v made of the same material and having the same shape as the stator-side vibrator 5v, and the rotor-side vibrator 6v is attached to an outer peripheral portion of a back surface (upper surface in the drawing) to form a stator-side elastic body 5e. A rotor-side elastic body 6e made of the same material and having the same shape is provided. As a result, the natural frequencies of the stator 5 and the rotor 6 are in the same state.

The vibrator 6v is attached to the back surface of the outer peripheral portion 6o of the rotor 6 similarly to the stator 5, and a thin intermediate portion 6m between the outer peripheral portion 6o and the inner peripheral portion 6i of the rotor 6 is provided.
Is the outer peripheral portion 6o, like the thin intermediate portion 5m of the stator 5.
And the outer peripheral portion 6o and the inner peripheral portion 6i
To suppress the transmission of vibration between them.

The rotary shaft 4 is inserted through through holes 3h, 5h formed in the center of the fixing base 3 and the stator 5, respectively, and is fitted to a bearing 7 fitted and fixed in the through hole 3h of the fixing base 3. It is rotatably supported. A boss 8 having a diameter larger than that of the rotary shaft 4 is provided above a position where the rotary shaft 4 is supported by the bearing 7. Inner circumference 6i of the rotor 6
Is located between the boss 8 and the stator-side elastic body 5e, and is press-fitted and fixed to the boss 8. A snap ring 9 such as a C-ring is attached to a lower portion of the rotating shaft 4. A compression spring 11 is inserted between the snap ring 9 and the bearing 7 via a spacer 10. I have. The compression spring 11 allows the rotation shaft 4 and the rotor 6
Is constantly biased downward.

The stator-side elastic member 5e has a narrow annular convex portion 5p integrally formed on the surface of the outer peripheral portion 5o, and the rotor-side elastic member 6e has a narrow circular member integrally formed on the surface of the outer peripheral portion 6o. It has an annular convex portion 6p. These projections 5p, 6p
Are arranged opposite to each other and have the same shape. Here, if the stator-side and rotor-side elastic members 5e and 6e are brought into full contact, the vibration on the excitation side is mostly transmitted to the partner side and the displacement of the traveling wave is attenuated. 5e and 6e have convex portions 5p and 6p, respectively, and since the press-contact surface is narrower than the entire surface contact, normal traveling waves are held in the stator-side and rotor-side convex portions 5p and 6p. be able to.

Between the stator-side protrusion 5p and the rotor-side protrusion 6p, an annular cushioning friction member 1 made of, for example, resin is provided.
2 intervenes, and the cushioning friction member 12 is in pressure contact with them. That is, the rotor-side convex portion 6p presses the stator-side convex portion 5p via the buffer friction member 12 by the elastic force of the compression spring 11.

The cushioning friction member 12 functions as a kind of vibration low-pass filter that operates so that the traveling wave generated in the stator-side convex portion 5p or the rotor-side convex portion 6p is hardly transmitted to the other side. Mutual interference between the traveling wave of the body 5e and the traveling wave of the rotor-side elastic body 6e is prevented to generate a normal traveling wave for both, and the metal (protrusion 5)
p, 6p) to avoid direct contact to prevent the generation of abnormal noise,
Further, the durability of the press contact portion is improved. The cushioning friction member 12 may not be fixed to any of the protrusions 5p and 6p, but may be interposed between the protrusions 5p and 6p, or may be fixed to any one of them.

A slip ring 13 composed of three rings 13a, 13b, and 13c that are disconnected from each other is fixed to the upper portion of the rotating shaft 4. For these rings 13a, 13b, 13c, the energizing brushes 15a, 1 for the rotor provided on the upper part of the fixing base 3.
5b and 15c are arranged so as to be in contact with each other.
The energizing brushes 15a and 15b respectively control the first drive signal of the second drive signal.
The component supply brush is a brush for supplying a second component of the second drive signal, and the energizing brush 15c is a ground brush. Here, the first component and the second component preferably have a 90 ° phase difference and are sine waves, but they may be square waves.

FIG. 2 is a plan view of one side of the above-described stator-side vibrator 5v or rotor-side vibrator 6v. The vibrators 5v and 6v include an annular piezoelectric ceramic plate CM,
Each of the piezoelectric ceramic plates CM includes four first electrode portions S1 to S4 and second electrode portions C1 to C4 formed on one surface of the piezoelectric ceramic plate CM. First electrode unit S1 to S4 and second electrode unit C1
.About.C4 are equally distributed at a mechanical angle of 36 DEG so that the vibrator can generate standing waves of 5 wavelengths (5.lambda.) In the entire circumferential direction. The first electrode units S1 to S4 and the second electrode units C1 to C4
The polarization processing is performed in advance so that the polarization directions in the thickness direction are opposite to each other (see + and-in the drawing) in the adjacent regions. The electrodes S1 to S4 and C1 to C4 are provided without leaving a gap between the inner edge and the outer edge of the annular piezoelectric ceramic plate CM.

FIG. 3 is a plan view of the other side of the stator-side vibrator 5v or the rotor-side vibrator 6v. On the other surface of the annular piezoelectric ceramic plate CM, a first side electrode portion SS facing the entire formation region of the first electrode portions S1 to S4 on one surface of the piezoelectric ceramic plate CM, and a second electrode portion C1 ~ C4
And the second side electrode portion CC opposed to the entire formation region of. Between the first side electrode portion SS and the second side electrode portion CC, there are provided feedback electrode portions FB and FB 'which face each other at a mechanical angle of 18 ° and an electrical angle of 90 °. .

Referring again to FIG. 1, the entire surface of the one side of the stator-side vibrator 5v is bonded to the back side of the metal elastic body 5e with an adhesive or a conductive adhesive. In general, even when a non-conductive adhesive is used, a small portion of the machined surface comes into contact because of the small thickness of the adhesive, and electrical conduction is achieved. The metal elastic body 5e is electrically connected to the fixing base 3, so that the electrode portions S1 to S4, FB, C1 to C4 formed on one surface of the stator-side vibrator 5v are connected to ground. I have.

On the other hand, the first side electrode portion SS and the second side electrode portion CC of the stator side vibrator 5v are connected to the drive circuit 16.

The drive circuit 16 applies a sine wave voltage signal, which is the first component of the first drive signal, between the ground and the first side electrode portion SS of the stator-side vibrator 5v.
A sine wave voltage signal as a second component of the first drive signal having a phase difference of 90 ° with the side electrode portion CC is applied. A piezoelectric voltage signal as a displacement detection signal generated between the feedback electrode portions FB and FB ′ according to the displacement amount of the vibrator 5v is input to the drive circuit 16, and a stator is generated based on the input displacement detection signal. The frequency and phase of the sine wave voltage signal supplied to the side vibrator 5v are kept constant.

The entire surface of the one side of the rotor-side vibrator 6v is bonded to the back side of the metal elastic body 6e using an adhesive or a conductive adhesive. Metal elastic body 6
e is an internal wiring 14c electrically connected thereto sequentially,
The rotor 13 is electrically connected to the fixing base 3 via the ring 13c and the energizing brush 15c.
v formed on one surface of the electrode portions S1 to S4, FB, C1
To C4 are connected to the ground.

On the other hand, the first side electrode portion SS of the rotor side vibrator 6v is connected to the internal wiring 14 electrically connected thereto sequentially.
a, a ring 13a, and an energizing brush 15a. The second side electrode portion CC of the rotor side vibrator 6v is connected to the internal wiring 1 electrically connected thereto sequentially.
4b, the ring 13b, and the energizing brush 15b are connected to the drive circuit 16.

The drive circuit 16 applies a first drive signal of the second drive signal between the ground and the first side electrode portion SS of the rotor-side vibrator 6v.
Apply a sine wave voltage signal as a component, and
A sine wave voltage signal as a second component of the second drive signal having a phase difference of 90 ° with the side electrode portion CC is applied.

Next, the operation of the ultrasonic motor constructed as described above will be described in more detail together with the drive circuit 16. From the drive circuit 16 to the first side electrode portion SS of the vibrator 5v
When the first drive power supply as the first component of the first drive signal is supplied to the vibrator 5v, the vibrator 5v is excited to generate a standing wave of five wavelengths along the circumferential direction on the elastic body surface.

Here, as described above, the thin intermediate portion 5m
As a result, the outer peripheral portion 5o to which the vibrator 5v is attached vibrates, so that the standing wave is applied to the outer peripheral portion 5o of the stator 5.
O occurs on the surface of o.

When the second drive power supply as the second component of the first drive signal having a phase difference of 90 ° with respect to the first drive power supply is supplied to the second side electrode portion CC, the outer peripheral portion 5o of the stator 5 is A standing wave of five wavelengths is generated on the surface along the circumferential direction. As described above, since the first side electrode portion SS and the second side electrode portion CC are separated by 90 ° in electrical angle, there is a phase difference of 90 ° between the standing waves.

Therefore, when the first drive power and the second drive power are simultaneously supplied from the drive circuit 16 to the stator-side vibrator 5v, a rotating traveling wave of a synthetic wave is formed on the surface of the outer peripheral portion 5o of the stator 5. Also, the first vibrator 6v
When the driving power and the second driving power are supplied simultaneously, the rotor 6
A rotating traveling wave due to the composite wave is formed on the surface of the outer peripheral portion 6o.

In the present embodiment, first, the frequency of the two-phase first drive signal supplied from the drive circuit 16 to the stator-side vibrator 5v is f, and the two-phase second drive supplied to the rotor-side vibrator 6v. The control circuit 17 controls the drive circuit 16 so that the frequency of the signal becomes f similarly.

Then, as described above, since the natural frequencies of the stator 5 and the rotor 6 match, the frequency f
Is the resonance frequency of the stator 5 and the rotor 6 or a frequency near the resonance frequency, as shown in FIG. 4, the rotating traveling wave A generated at the convex portion 5p of the stator-side outer peripheral portion 5o and the convex portion of the rotor-side outer peripheral portion 6o. The rotating traveling wave B generated at 6p matches and locks as if the gears were meshed. For this reason, the rotor 6 is in a stopped state. Here, in the present embodiment, the frequency f is set to, for example, 50 kHz.

In this state, the frequency of the two-phase first drive signal supplied from the drive circuit 16 to the stator-side vibrator 5v is f, and the frequency of the two-phase second drive signal supplied to the rotor-side vibrator 6v is f. Is set to (f + Δf) by the control circuit 17.
Controls the driving circuit 16, the rotating traveling wave B on the rotor side of the meshing rotating traveling waves A and B tries to advance relatively to the rotating traveling wave A on the stator side. In the stationary state, the engagement lock position of the rotating traveling waves A and B advances in the traveling direction of the traveling wave, and the rotor 6 rotates forward.

On the other hand, the frequency of the two-phase first drive signal supplied from the drive circuit 16 to the stator-side vibrator 5v is f, and the frequency of the two-phase second drive signal supplied to the rotor-side vibrator 6v is ( When the control circuit 17 controls the drive circuit 16 so that f−Δf), of the meshed rotational traveling waves A and B, the rotational traveling wave B on the rotor side becomes the rotational traveling wave A on the stator side. To try to be relatively late,
In a state where the stator 5 is not moved, the meshing lock position of the rotating traveling waves A and B advances in the direction opposite to the traveling direction of the traveling wave, and the rotor 6 rotates in the reverse direction.

Further, when the variable amount ± Δf of the frequency is increased or decreased, the rotation speed of the rotor 6 is increased or decreased. The rotation speed (rpm) based on the ± Δf value indicates a synchronous rotation speed determined by 60 × Δf / wave number. For example, in the case of the 5-wave type shown in FIG. 2, when Δf is 1 Hz, 60 ×× = 12 rpm.

As described above, in the present embodiment, the vibrators 5v and 6v are made of the same material and have the same shape, and the elastic members 5e and 6e are made of the same material and have the same shape. As the shape, the stator 5 and the rotor 6
Are set to be equal to each other, by supplying signals of the resonance frequency of the stator 5 and the rotor 6 or frequencies near the resonance frequency to the vibrators 5v and 6v, respectively.
The generated traveling waves A and B are locked as if the gears meshed (coincided), and the rotor 6 was stopped.
By shifting the phase of one signal to positive or negative with respect to the other, the meshing lock position shifts in the forward direction or the reverse direction, and the rotor 6 rotates forward or reverse due to the continuation of this shift amount. Has become.

That is, in the ultrasonic motor provided with the vibrators 5v and 6v in both the stator 5 and the rotor 6, both vibrators 5v and 6v are made of the same material and have the same shape, Since the bodies 5e and 6e are made of the same material and have the same shape, the rotation of the rotor 6 can be controlled well.

Here, the natural frequencies of the stator 5 and the rotor 6 are shifted by the influence of temperature, humidity, load, applied pressure, drive power, and the like.
If the natural frequency shift amount is different, the meshing lock of the traveling waves A and B may be broken, but as described above,
Since both vibrators 5v and 6v are made of the same material and have the same shape, and both elastic bodies 5e and 6e are made of the same material and have the same shape, both natural frequencies are in the same direction. Are shifted by the same amount.

That is, according to the present embodiment, the engagement lock between the traveling waves A and B does not break, and the rotor 6
The rotation can always be controlled satisfactorily.

The two vibrators 5v and 6v and the two elastic members 5
Since e and 6e can be shared, the cost can be reduced.

FIG. 5 is a cross-sectional view showing an ultrasonic motor according to the second embodiment. The ultrasonic motor of the second embodiment is different from that of the first embodiment in that the elastic body 5e on the stator 5 side and the elastic body 6e on the rotor 6 side are each composed of a plurality of elastic bodies, The feature is that the corresponding elastic bodies on the rotor side are made of the same material and have the same shape.

That is, the stator-side elastic body 5e has a thick outer peripheral portion 5 to which the thin intermediate portion 5ma and the vibrator 5v are attached.
o, and a thick inner peripheral portion (other member) 5ia fixed to the fixing base 3, while the rotor-side elastic body 6e has a thin intermediate portion 6ma and a vibrator 6v. Member 6 composed of a thick outer peripheral portion 6o to which is attached
ea and a thick inner peripheral portion (other member) 6ia which is press-fitted and fixed to the boss 8, and one member 5ea, 6e
a is made of an elastic body made of the same metal and has the same shape. Both thick inner peripheral portions 5ia and 6ia are made of an elastic body made of the same metal and have the same shape.

The one member 5ea on the stator side has a thin intermediate portion 5ma on the inner peripheral portion 5ia, and the one member 6ea on the rotor side has the thin intermediate portion 6ma on the inner peripheral portion 6ia.
Are fixed by, for example, screws. In order to perform the screw fastening, the stator-side thin intermediate portion 5ma and the rotor-side thin intermediate portion 6ma are respectively provided with inner peripheral portions 5ia and 6ia.
It is configured to overlap.

Even with this configuration, the natural frequencies of the stator 5 and the rotor 6 can be matched, so that the same effects as in the first embodiment can be obtained.

In addition, even if the shape accuracy of the inner peripheral portions 5ia and 6ia is made rougher than the shape accuracy of the one member 5ea and 6ea, the inner peripheral portions 5ia and 6ia do not generate vibrations for driving. Since the engagement lock of the traveling waves A and B on the pressure contact surface is hardly affected, the inner peripheral portions 5ia and 6 are not affected.
Because the shape accuracy of ia can be roughened, the manufacturing cost can be reduced.

FIG. 6 is a transverse sectional view showing an ultrasonic motor according to the third embodiment. The ultrasonic motor according to the third embodiment is different from the ultrasonic motor according to the second embodiment in that the coupling position between the divided elastic members is changed from the inner peripheral side to the outer peripheral side with respect to the vibrator. The point is that the shapes of 5e and the rotor side elastic body 6e are changed.

That is, the stator-side elastic body 5e has a vibrator fixing portion (the first and second embodiments) in which the stator-side vibrator 5v is adhered and has a convex portion 5p to press against the cushioning friction member 12. The same member as the outer peripheral portion) 5o, one member 5eb composed of a thin intermediate portion 5mb continuously provided on the outer peripheral side of the transducer fixing portion 5o, and a thick inner peripheral portion 5ib fixed to the fixing base 3, It is divided into another member 5im which is provided continuously with the thick inner peripheral portion 5ib and has a support portion 5mc shaped to cover the thin intermediate portion 5mb and the vibrator fixing portion 5o from below.
On the other hand, the rotor-side elastic body 6e has a vibrator fixing portion (to which the outer peripheral portion of the first and second embodiments is attached) to which the rotor-side vibrator 6v is attached and which has the convex portion 6p and presses against the cushioning friction member 12. The same thing) 6o, one member 6eb composed of a thin intermediate portion 6mb continuously provided on the outer peripheral side of the transducer fixing portion 6o, a thick inner peripheral portion 6ib press-fitted and fixed to the boss 8, and this thick inner peripheral The member 6eb is divided into another member 6im which is provided continuously with the portion 6ib and includes a support portion 6mc shaped to cover the thin intermediate portion 6mb and the vibrator fixing portion 6o from above.
eb is made of an elastic body made of the same metal and has the same shape, and the other members 5im and 6im are made of an elastic body made of the same metal and has the same shape.

The one member 5eb on the stator side has a thin intermediate portion 5mb whose supporting portion 5mc supports the other member 5im.
Meanwhile, one member 6eb on the rotor side has a thin intermediate portion 6m.
b is fixed to the support portion 6mc of the other member 6im by, for example, a screw or the like.

Even with such a configuration, the natural frequencies of the stator 5 and the rotor 6 can be matched, so that it is needless to say that the same effect as in the second embodiment can be obtained.

In the second and third embodiments,
Among the elastic members 5e and 6e, one elastic member (other member) other than the elastic member to which the vibrators 5v and 6v are attached is used, but other than the elastic member to which the vibrators 5v and 6v are attached. May be two or more. In short, each elastic body 5
e, 6e are composed of one member provided with the vibrators 5v, 6v and pressed against another opposing elastic body, and at least one or more other members. The number of constituent members is not limited as long as the corresponding members of the elastic bodies are formed of the same material and have the same shape.

In the second and third embodiments, all the members constituting the stator-side and rotor-side elastic members 5e, 6e may be made of the same material. When the material of one member is made different from that of another member, it is preferable to adopt a material having a similar thermal expansion coefficient in consideration of, for example, the effect of thermal expansion during rotation.

As described above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the above embodiment, and can be variously modified without departing from the gist thereof. Needless to say,
For example, in the above embodiment, the natural frequencies of the stator 5 and the rotor 6 can be better matched, and in the first embodiment, both vibrators 5v and 6v are made of the same material and have the same shape. At the same time, both elastic bodies 5e, 6e
The whole is made of the same material and has the same shape. In the second and third embodiments, both vibrators 5v and 6v are made of the same material and have the same shape. 5ea and 6ea, 5ia and 6i
a (2nd Embodiment), 5eb and 6eb, 5im and 6im
In the third embodiment, the two vibrators 5v and 6v are made of the same material and have the same shape, and are used for driving the stator-side elastic body 5e. The vibrating portion (the outer peripheral portion of the first and second embodiments, the vibrator fixing portion of the third embodiment) 5o and the vibrating portion (the first and second portions) used for driving the rotor-side elastic body 6e are provided.
Outer peripheral portion of the embodiment, vibrator fixing portion of the third embodiment) 6o
Only the same material may be used to form the same shape.

Even with such a configuration, the stator-side vibrator 5 comprising the vibrator 5v and the vibrating portion 5o used for driving.
Since the natural frequency of g is the same as the natural frequency of the vibrator 6v and the vibrating body 6g on the rotor side, which is composed of the vibrating portion 6o used for driving, substantially the same operation and effect as described in the above embodiment can be obtained.

In the above embodiment, application to an ultrasonic motor that generates a traveling wave by a two-phase drive signal is described. However, the present invention is applied to an ultrasonic motor that generates a traveling wave by a drive signal of three or more phases. The same can be applied to this.

[0060]

According to the ultrasonic motor of the present invention, both vibrators are made of the same material and have the same shape, and at least the vibrating portions for driving the elastic bodies are made of the same material and have the same shape. The natural frequencies of the vibrating body, which includes at least the vibrating part used for driving the vibrator and the elastic body, are matched. For this reason, when signals of the resonance frequency of the vibrator or a frequency near the resonance frequency are supplied to both vibrators, traveling waves generated on the press-contact surface can be matched. As a result, if the meshing lock position of the traveling wave is continuously shifted, the rotation of the rotor can be favorably controlled. Also, the natural frequency of the vibrating body shifts due to the influence of temperature, humidity, load, pressing force, drive power, and the like. However, as described above, since at least the vibrating portion and both vibrators used for driving both elastic members are formed of the same material and have the same shape, both natural frequencies are Shift by the same amount in the same direction. That is, the engagement lock of the traveling wave does not break, and the rotation of the rotor can always be satisfactorily controlled. In addition, since at least the vibrating portion and both vibrators used for driving the two elastic members are made of the same material and have the same shape, parts can be shared and cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an ultrasonic motor according to a first embodiment.

FIG. 2 is a plan view of one side of a stator-side vibrator or a rotor-side vibrator.

FIG. 3 is a plan view of the other side of a stator-side vibrator or a rotor-side vibrator.

FIG. 4 is a sectional view taken along a circumferential direction of a stator / rotor contact portion when a traveling wave is generated.

FIG. 5 is an enlarged cross-sectional view showing a stator and a rotor portion of an ultrasonic motor according to a second embodiment.

FIG. 6 is an enlarged cross-sectional view illustrating a stator and a rotor portion of an ultrasonic motor according to a third embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Ultrasonic motor main body, 2 ... Electric control part, 5 ... Stator (stator), 5e ... Stator side elastic body (fixed side elastic body), 5ea, 5eb, 6ea, 6eb ... One member which comprises an elastic body 5g, 6g ... vibrator, 5ia, 5im,
6ia, 6im: Other members constituting the elastic body, 5o, 6
o: vibrating portion for driving the elastic body; 5v: stator side vibrator (fixed side vibrator); 6 ... rotor (rotor); 6e
... rotor side elastic body (movable side elastic body), 6v ... rotor side vibrator (movable side vibrator).

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[Procedure amendment]

[Submission date] February 17, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006]

An ultrasonic motor according to the present invention comprises a fixed-side elastic body and a fixed-side vibrator provided on the fixed-side elastic body and fixed to a fixing member.
A movable-side elastic body opposed to and pressed against the fixed-side elastic body, and a rotor fixed to a rotating shaft, which is configured by a movable-side vibrator provided on the movable-side elastic body; In the ultrasonic motor that drives the rotor by a traveling wave generated on the press-contact surface of each elastic body in response to the vibration, the two vibrators are vibrated by supplying signals of the respective frequencies. A first portion provided with a convex portion and a vibrator that are in pressure contact with another elastic body to be pressed, and a second portion other than the first portion, and the fixed-side and movable-side elastic bodies correspond to each other. The first portion is made of the same material and has the same shape, and the second portion is made of a material different from that of the first portion.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

According to the ultrasonic motor of the present invention, the first portion having the projections and the vibrators of the two elastic members is a vibrating portion for driving the elastic members, and the two vibrating portions are made of the same material. Since they are formed in the same shape, their natural frequencies match. Therefore, when signals of the resonance frequency of the first portion or a frequency in the vicinity thereof are supplied to both the vibrators, the traveling waves generated on the pressure contact surfaces of the two elastic bodies are locked as if the gears are meshed with each other. ) The rotor is stopped, and the phase of one signal is shifted positively or negatively with respect to the other, so that the meshing lock position shifts in the forward direction or the reverse direction. Rotor rotates forward or reverse. That is, by employing the above configuration, the rotation of the rotor can be favorably controlled.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

In addition, since the first portions of the two elastic members are made of the same material and have the same shape, the parts are shared and the cost is reduced.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

Here, the natural frequency of the elastic body is shifted by the influence of temperature, humidity, load, applied pressure, drive power, and the like. Although the engagement lock of the traveling wave may be broken, as described above, the first portions that are the vibrating portions of the two elastic bodies are made of the same material and have the same shape. The frequencies are shifted by the same amount in the same direction. That is, the meshing lock of the traveling wave does not break down, and the rotor can always be controlled to rotate well.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

Further, even if the shape accuracy of the second portion other than the first portion of the elastic body is roughened as compared with the shape accuracy of the first portion which becomes the vibrating portion of the elastic body, the shape of the press contact surface can be reduced. Of the traveling wave is hardly affected. Therefore, if the second portion is made of a material different from that of the first portion, and the shape accuracy of the second portion is rougher than the shape accuracy of the first portion, the manufacturing cost can be reduced. It is planned.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Deleted

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction contents]

That is, the stator-side elastic body 5e has a thick outer peripheral portion 5 to which the thin intermediate portion 5ma and the vibrator 5v are attached.
o, and a thick inner peripheral portion (another member; second portion) 5ia fixed to the fixing base 3; and a rotor-side elastic body. 6e
Is a member (first portion) 6ea including a thin middle portion 6ma and a thick outer peripheral portion 6o to which the vibrator 6v is attached,
It is divided into a thick inner peripheral portion (other member; second portion) 6ia which is press-fitted and fixed to the boss 8, and one member 5ea, 6
ea is made of an elastic body made of the same metal and has the same shape. Both thick inner peripheral portions 5ia and 6ia are made of an elastic body made of the same metal and different from one member. It is shaped.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0060

[Correction method] Change

[Correction contents]

[0060]

According to the ultrasonic motor of the present invention, the first portions, which are the vibrating portions used for driving the two elastic members, are made of the same material, have the same shape, and have the same natural frequency. For this reason, when signals of the resonance frequency of the first portion or a frequency in the vicinity thereof are supplied to both vibrators, traveling waves generated on the press contact surface can be matched. As a result, if the meshing lock position of the traveling wave is continuously shifted, the rotation of the rotor can be favorably controlled. In addition, since the natural frequency of the elastic body shifts due to the influence of temperature, humidity, load, pressing force, drive power, and the like, if the natural frequency shift amounts of both elastic bodies are different, the meshing lock of the traveling wave is reduced. However, as described above, since the first portions, which are the vibrating portions of both elastic members, are formed of the same material and have the same shape as described above, the two natural frequencies are in the same direction. Shift by the same amount. That is, the engagement lock of the traveling wave does not break, and the rotation of the rotor can always be satisfactorily controlled. Further, since the first portions of the two elastic bodies are formed of the same material and have the same shape, the components can be shared, and the cost can be reduced. Further, even if the shape accuracy of the second portion other than the first portion of the elastic body is roughened compared to the shape accuracy of the first portion which is the vibrating portion of the elastic body, the traveling wave on the pressure contact surface can be reduced. The meshing lock is hardly affected. Therefore, the second portion is made of a material different from that of the first portion, and the shape accuracy of the second portion is made rougher than the shape accuracy of the first portion, thereby reducing manufacturing cost. Can be achieved.

Claims (4)

[Claims] 1. A fixed-side elastic body, a stator including a fixed-side vibrator provided on the fixed-side elastic body, a movable-side elastic body opposed to and pressed against the fixed-side elastic body, and the movable-side elastic body. And a rotor composed of a movable-side vibrator provided to the vibrator, and by supplying a signal of a predetermined frequency to both vibrators, the two vibrators are vibrated. In an ultrasonic motor that drives the rotor by a traveling wave generated on a pressure contact surface of each elastic body, the two vibrators are made of the same material and have the same shape, and the two elastic bodies are at least used for driving. The vibration part to provide
An ultrasonic motor comprising the same material and the same shape. 2. The apparatus according to claim 1, wherein the signal of the predetermined frequency is a signal of a resonance frequency of a vibrating body including at least the vibrator and a vibrating portion used for driving the elastic body or a frequency near the resonance frequency. 2. The ultrasonic motor according to 1. 3. The ultrasonic motor according to claim 1, wherein the two elastic bodies are made of the same material and have the same shape. 4. Each of the elastic bodies includes a member provided with the vibrator and pressed against another opposing elastic body, and at least one or more other members. The ultrasonic motor according to claim 1, wherein members corresponding to the fixed side and the movable side elastic bodies are formed of the same material and have the same shape.