JP2000060157A - Ultrasonic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable extracting a plurality of drive forces with a simplified high frequency voltage circuit by sticking an annular piezoelectric member common to a plurality of annular resonance parts on an annular elastic body, and connecting transformers generating each high frequency voltage, corresponding to each resonance frequency of the annular resonance parts with the piezoelectric member. SOLUTION: On the bottom surfaces of an inner peripheral side annular part 4 and an outer peripheral side annular part 5 which are annular resonance parts, a piezoelectric member 7 common to the annular parts 4, 5 is stuck. The secondary side of a transformer 13 is connected with an A phase of the piezoelectric member 7. The secondary side of a transformer 14 is connected with a B phase of the piezoelectric member 7. A high-frequency voltage Va1 for resonating the annular part 4 is inputted to the primary side of the transformer 13. A 90 degree high-frequency voltage Vb1 is inputted in the primary side of the transformer 14. A high-frequency voltage Va2 for resonating the annular part 5 is inputted in the primary side of the transformer 13. a high-frequency voltage Vb2 whose phase is shifted by 90 degrees is inputted in the primary side of the transformer 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic motor.

[0002]

2. Description of the Related Art Heretofore, a stator formed by pasting a ring-shaped piezoelectric body to a ring-shaped elastic body, and a stator provided coaxially with the stator and resiliently contacting the elastic body. In the ultrasonic motor having the rotor set as described above, a high-frequency voltage, which is out of phase with each other, is applied to the piezoelectric body at the same time to generate a traveling wave in the elastic body, and the vibration causes a vibration with respect to the rotor. There is one that obtains a driving force in a direction.

In such an ultrasonic motor, a plurality of driving forces are provided from a rotor which is provided concentrically with annular elastic bodies having different diameters and which are independently rotatable in correspondence with the respective elastic bodies. However, as a driving structure in such a case, a ring-shaped piezoelectric body corresponding to each of the ring-shaped elastic bodies having different diameters is attached, and a high-frequency voltage circuit is provided for each of the piezoelectric bodies. Conceivable.

[0004]

However, in the above structure, if a plurality of driving forces are to be obtained, the same number of high-frequency voltage circuits will be required.
Accordingly, the number of power supply lead wires is similarly increased, and there is a problem that not only the number of parts but also the number of assembly steps are complicated.

[0005]

SUMMARY OF THE INVENTION In order to solve such a problem and realize a plurality of driving forces to be taken out by a simplified high-frequency voltage circuit, the present invention employs the same driving force. An annular elastic body having a plurality of annular resonators having different diameters concentric with each other and radially divided by a circumferential groove on a plane, and respectively corresponding to the plurality of annular resonators and independently of each other; A plurality of rotors rotatably provided, affixed to the annular elastic body an annular piezoelectric body common to the plurality of annular resonators, and each of the plurality of annular resonators. A transformer that generates different high-frequency voltages corresponding to the resonance frequency alone or in combination is connected to the piezoelectric body.

According to this, by providing a plurality of toroidal resonating portions obtained by dividing the toroidal elastic body in the radial direction by the circumferential grooves, the toroidal resonating portions have different resonance frequencies, and each toroidal resonating portion has By applying a common high-frequency voltage to the piezoelectric body by attaching a common piezoelectric body to the toroidal elastic body, a plurality of toroidal resonators alone or in combination can resonate simultaneously. Can be done.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to specific examples shown in the accompanying drawings.

FIG. 1 is a side sectional view of an ultrasonic motor to which the present invention is applied. As shown in FIG. 1, a step-like boss 1a is provided at the center of the bottom wall of the case 1 so as to protrude upward, and the lowermost part thereof has a disk shape having an opening at the center. The elastic body 2 is fixed coaxially by screwing the outer peripheral portion of the opening. The first drive shaft 3 is coaxially and rotatably mounted on the uppermost portion of the boss 1a via a bearing.
Is supported.

The elastic body 2 is divided in the radial direction by a central annular portion screwed to the boss 1a, a case connecting portion 2a extending radially outward from the central annular portion, and a circumferential groove 2b. And a plurality of annular resonating sections 4 and 5. The respective annular portions 4 and 5 are arranged concentrically with respect to the boss portion 1a (first drive shaft 3), and mutually connected via a connecting portion 6 serving as a bottom wall of the circumferential groove 2b. Are linked.

The connecting portion 6 is provided such that the center of the connecting portion 6 is located at a position (a position where no bending stress occurs) in the axial direction of the annular portions 4 and 5 in the axial direction. The connecting portion 6 is formed by processing the circumferential groove 2b and also processing the circumferential groove 2c on the side of the connecting portion 6 opposite to the circumferential groove 2b.

A piezoelectric member 7 made of one annular thin plate common to both annular portions 4 and 5 is attached to the bottom surfaces (lower surfaces in the drawings) of the annular portions 4 and 5. As shown in FIG. 2, one of the axial end faces of the annular portions 4 and 5 on the side opposite to the side on which the piezoelectric body 7 is adhered (upper part in the drawing) has a circumferential direction. By providing a plurality of radial slits at equal pitch intervals, an inner comb portion 4a and an outer comb portion 5a having an annular comb shape are respectively formed. Thus, the stator is configured.

Since the annular portions 4 and 5 are concentrically arranged on the same plane, the axial length of the motor device can be minimized. Also, since a relatively large torque is obtained as a characteristic of the ultrasonic motor,
Since the size is not increased in the radial direction, a compact and thin structure can be achieved.

The inner peripheral rotor 8 includes a thin disk portion 8a as a disc spring extending integrally from the bearing portion of the first drive shaft 3 in a radially outward direction, and a wall provided on the outer peripheral portion thereof. And a peripheral wall 8b having a large thickness.
Is integrated with a cylindrical second drive shaft 10 rotatably and coaxially provided on the first drive shaft 3 via a bearing, and like the inner peripheral rotor 8, the second drive shaft It has a thin disk portion 9a as a disc spring extending integrally in the radial direction outward from the bearing portion 10 and a thick peripheral wall portion 9b provided on the outer peripheral portion thereof.

The inner peripheral annular portion 4 has an axial lower end surface of the peripheral wall portion 8b of the inner peripheral rotor 8, and the outer peripheral annular portion 5 has an axial line of the peripheral wall portion 9b of the outer peripheral rotor 9. The lower end surfaces in the direction resiliently come into contact with the respective thin disk portions 8a and 9a by the disc spring action.

As shown in FIG. 3A, the piezoelectric body 7 has electrode groups 12a and 12a each having a polarization pattern to which a high-frequency voltage is input from an AC power supply 11 and having a substantially symmetrical semi-circular shape in the figure. 12b. In order to enable the respective rotors 8 and 9 to rotate forward and backward, the A-phase (corresponding to the electrode group 12a) and the B-phase (corresponding to the electrode group 12b), which are formed in a substantially symmetrical semicircular arc in FIG. ).

As shown in FIG. 4, the secondary side of the transformer 13 is connected to the A phase of the piezoelectric body 7, and the secondary side of the transformer 14 is connected to the B phase of the piezoelectric body 7. A high-frequency voltage Va1 for resonating the inner annular portion 4 is supplied to the primary side of the transformer 13 by a high-frequency voltage Vb1 having a phase shift of 90 degrees.
Are input to the primary side of the transformer 14, respectively. Also, a high-frequency voltage Va2 for resonating the outer annular portion 5 is input to the primary side of the transformer 13, and a high-frequency voltage Vb2 having a phase shift of 90 degrees is input to the primary side of the transformer 14.

FIG. 5 shows a control circuit applied to the present invention. The switching circuit 21 shown in FIG. 5 is connected to a changeover switch having a three-position changeover contact, and is connected to the inner annular portion 4 and the outer annular portion. This is for switching one or both of the units 5 to be driven simultaneously. On the output side of the switching circuit 21, a first oscillation circuit 22 for generating the resonance frequency of the inner annular portion 4 and a second oscillation circuit 23 for generating the resonance frequency of the outer annular portion 5 are provided. Is connected. The outputs of the oscillation circuits 22 and 23 are respectively connected to the corresponding amplification circuits 24 and 25 and the phase circuits 26 and 2 for shifting the phase by 90 degrees with respect to the outputs of the oscillation circuits 22 and 23.
7 and input. The high-frequency voltage Va1 is output from the one amplifier circuit 24 and the high-frequency voltage Va2 is output from the other amplifier circuit 25 to the transformer 13 in accordance with the output of each of the oscillation circuits 22 and 23.

In each of the phase circuits 26 and 27, B
A forward / reverse selection command is input from a forward / reverse selection circuit 28 connected to a selection switch having a two-position selection contact for selecting whether to delay or advance the phase of phase A with respect to phase A. ing. In response to the forward / reverse selection command,
Oscillation outputs obtained by delaying or advancing the phase by 90 degrees with respect to the A phase from each of the phase circuits 26 and 27 are input to the correspondingly connected amplifier circuits 29 and 30, respectively. A high-frequency voltage Vb1 having a 90-degree phase shift with respect to the high-frequency voltage Va1, and a high-frequency voltage Vb2 having a 90-degree phase shift with respect to the high-frequency voltage Va2 are output from the other amplifier circuit 30 to the transformer 14.

Thus, one set of the high-frequency voltages V
When a1 · Vb1 is input to the transformers 13 and 14, a corresponding high-frequency voltage is applied to each of the A-phase and the B-phase, and the piezoelectric body 7 vibrates at a predetermined frequency. 4, a traveling wave accompanying the resonance is generated, and the first drive shaft 3 rotates. Also, the other set of high-frequency voltages Va
When 2 · Vb2 is input to the transformers 13 and 14, the piezoelectric body 7 vibrates at a predetermined frequency different from the above, and a traveling wave accompanying the resonance of the outer annular portion 5 is generated. Rotates the second drive shaft 10. The forward / reverse rotation is determined by the selection signal of the selection circuit 28.

In the case where the corresponding one vibrates due to the high frequency voltage applied to one of the annular portions 4 and 5, the amplitude thereof vibrates around the neutral plane. According to this, since the connecting portion 6 is provided on the neutral surface where no amplitude is generated, no vibration is transmitted to the other of the annular portions 4 and 5 via the connecting portion 6. Therefore, the amplitude due to the corresponding resonance due to the input of one of the resonance frequencies is not transmitted to the other via the connecting portion 6,
Since mutual vibration propagation can be prevented, each of the annular portions 4 and 5 can resonate independently, and a separate driving force can be independently taken out from each of the drive shafts 3 and 10. it can.

As described above, even when the common piezoelectric body 7 is used, a high-frequency voltage corresponding to each of the annular portions 4 and 5 is selectively applied to extract a driving force from a desired driving shaft. Can be. Also, high-frequency voltages corresponding to the two annular portions 4 and 5 may be applied at the same time, in which case separate driving forces can be taken out at the same time.

Further, the number of lead wires to be connected to the piezoelectric body 7 provided with the A phase and the B phase requires a total of three wires including the ground wire. In the case of a sound wave motor, a total of six leads are required if a piezoelectric body is provided for each drive shaft. According to the present invention, a minimum of three lead wires is required for the common piezoelectric body 12. The number of lead wires and the number of connection steps can be reduced as much as possible. Also, the number of transformers can be similarly reduced. In particular, according to the present invention, the number of lead wires and the number of transformers are further increased when the number of leads is three or more.

[0023]

As described above, according to the present invention, by providing a plurality of annular resonating parts obtained by dividing an annular elastic body in a radial direction by a circumferential groove, different resonance frequencies are obtained. By applying a common high frequency voltage to the piezoelectric body corresponding to each of the piezoelectric bodies by attaching a common piezoelectric body to the annular elastic body to each of the annular resonators, a plurality of annular resonators can be used alone or in combination. Can be simultaneously resonated, so that it is not necessary to configure independent high-frequency voltage circuits and circuits for connecting to the piezoelectric bodies according to the number of drive shafts, and the circuit can be simplified as much as possible. .

[Brief description of the drawings]

FIG. 1 is a side sectional view of an ultrasonic motor to which the present invention is applied.

FIG. 2 is an exploded perspective view of a main part of the ultrasonic motor of FIG. 1;

3A is a plan view showing a polarization pattern of a piezoelectric body, and FIG. 3B is a plan view showing A-phase and B-phase surface electrodes on the back surface thereof.

FIG. 4 is a block diagram showing a high-frequency voltage input circuit to a piezoelectric body according to the present invention.

FIG. 5 is a block diagram showing a high-frequency generation control circuit applied to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Case, 1a boss part 2 Elastic body, 2a case connection part, 2b, 2c circumferential groove 3 1st drive shaft 4 inner peripheral side annular part, 4a inner peripheral side comb tooth part 5 outer peripheral side annular part, 5a outer periphery Side comb teeth 6 Connecting part 7 Piezoelectric body 8 Inner peripheral rotor, 8a thin disk part, 8b peripheral wall part 9 Outer peripheral rotor, 9a thin disk part, 9b peripheral wall part 10 Second drive shaft 11 AC power supply 12 Electrode group , 12a, 12b Electrode 13, 14 Transformer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Koji Kobayashi Inventor 1-2681, Hirosawa-cho, Kiryu-shi, Gunma F-term (reference) 5H680 AA00 AA06 AA08 AA19 BB03 BB16 BB19 BB20 CC07 DD01 DD23 DD35 DD53 DD75 DD85 DD87 DD92 DD98 EE10 FF04 FF08 FF26 FF31 FF33

Claims (1)

[Claims] 1. An annular elastic body having a plurality of annular resonating portions of different diameters concentric with each other and radially divided by a circumferential groove on the same plane, and respectively corresponding to the plurality of annular resonating portions. And a plurality of rotors rotatably provided independently of each other, and affixing an annular piezoelectric body common to the plurality of annular resonating portions to the annular elastic body, An ultrasonic motor, wherein a transformer for generating each of different high-frequency voltages corresponding to each resonance frequency of the toroidal resonance section, alone or in combination, is connected to the piezoelectric body.