JPH0640745B2 - Twin resonance type ultrasonic motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use and object of the invention] The present invention relates to an improvement of an ultrasonic motor, and has a simple structure, a large output per volume, a high efficiency, and an electrically rotating direction. An object is to provide an ultrasonic motor that can be controlled arbitrarily.

[Conventional technology]

In the ultrasonic motor configured such that the rotor crimped to the end surface of the stator receives the rotational torque, ultrasonic elliptical vibration must be generated at the end surface of the stator. For this purpose, the stator may be a torsion mode ultrasonic elliptical oscillator, but conventionally, since such a torsion mode elliptical oscillator is not found, it has been difficult to realize an ultrasonic motor.

In other words, most of the ultrasonic transducers that have been put into practical use in the past are Langevin-type vertical mode transducers, and it is not easy to generate torsional mode elliptical vibrations using them, and the structure becomes complicated. However, there was a drawback that it was difficult to make it compact. Further, there are many transmission losses of ultrasonic energy from the ultrasonic oscillator to the stator, the efficiency of the motor is low, and the direction of rotation of the motor cannot be electrically changed easily.

[Means for solving problems]

This invention solves the above-mentioned drawbacks of the prior art.
An ultrasonic torsional oscillator composed of a structure in which a plurality of bending oscillators having the same resonance frequency are coupled to each other and configured to excite torsional vibration with a piezoelectric body is excited in parallel with the torsion axis by using another piezoelectric body. The twin resonance ultrasonic motor is characterized in that a rotating torque is generated in the rotor by crimping the rotor to the end surface of the twin resonance type ultrasonic elliptical oscillator in which a twist elliptical motion is generated in the end surface. That is why the purpose was achieved.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing an embodiment of a twin resonance type ultrasonic motor according to the present invention. The rotation output shaft 21 is fixed to the rotor 17, rotates at a rotational speed of 10 to 60 rpm slowly, and is rotated so strongly that a torque of several tens of kg · cm is required to stop it. The rotor 17 is crimped to the twin resonator 1 by a cap bolt 18 having a diameter of 4 mm which is passed through a coil spring 19 supported by a bearing 20. Since ultrasonic elliptical vibration is generated on the crimping surface between the twin resonator 1 and the rotor 17, a strong rotational torque is generated in the crimped rotor 17 having a thickness of 5 mm and a diameter of 30 mm. .

As shown in FIGS. 2 and 3, the ultrasonic elliptical oscillator has an excitation source that excites torsional bending vibration in the aluminum biresonator 1 having a size of 10 mm × 10 mm and 2 mm.
Four sets of piezoelectric vibrators 2, 3, 4 (not shown), 5 made of thick Pb (Zr, Ti) O ₃ piezoelectric ceramic square plates, two pairs each, and the same ceramics stacked via a washer 6. The doughnut-shaped piezoelectric thickness vibrator 7 having a diameter of 35 mm, an inner diameter of 15 mm and a thickness of 2 mm is formed of a piezoelectric body. These are diameter 3
With a cap bolt 9 having a diameter of 8 mm and a length of 20 mm, which is passed through a disk-shaped bolt washer 6 having a thickness of 5 mm and a thickness of 12.5 mm, a torque of several tens of kg · cm is applied to the screw hole of the twin resonator 1. Tightened and integrated. The piezoelectric vibrators 2 and 4 are superposed on each other with terminal plates with lead wires 12 and 14 facing each other facing the positive polarization surface, and the piezoelectric vibrators 3 and 5 are facing each other with the negative polarization surface facing each other. When the lead wires 12, 13, 14, 15 are made common and a sinusoidal voltage of 38 KHz is applied between these and the lead wire 16, the two beams of the twin resonator 1 bend and resonate in opposite phases, Looking at the tip surfaces 1'of the two beams, a torsional vibration force is generated. The lead wire 10 of the piezoelectric thickness oscillator 7 is connected to the lead wires 12, 13, 14, and 15, and the lead wire 11
When the voltage is applied again with the lead wire connected to the lead wire 16, a twist elliptical motion is generated in the front end surface 1 ′ of the twin resonator 1,
The rotor 17 started to rotate strongly at about 60 rpm. While keeping the frequency of the applied voltage the same, the voltage is 50V, 70V
Both the number of rotations and the torque increased. The variable range of the rotation speed was about 10 to 100 rpm.

The configuration of the ultrasonic motor shown in FIG. 1 is a schematic diagram, so the motor case is omitted, but it goes without saying that a practical product can be housed in the case for protection. Yes.

In this embodiment, the twin resonator 1 used in the twin resonance type ultrasonic vibrator is exemplified by a bending vibrator composed of two beams made of square aluminum having a cross section of 10 mm × 10 mm. As long as the resonance frequencies can be equalized, any number of children can be combined. For example, the shapes of bending oscillators in three 3-pole twin resonators and four 4-pole twin resonators are shown in FIGS. 4 and 5, respectively. In these figures, 31, 41 are three or four twin resonators, 31 ',
41 'is the front end face of the twin resonators 31, 41, 32, 42
Is a washer.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention has a structure in which a plurality of bending oscillators having the same resonance frequency are coupled, and an ultrasonic torsion oscillator configured to excite the torsion oscillator by a piezoelectric body When a rotor is crimped to the end face of a bi-resonant ultrasonic elliptical oscillator in which a torsion elliptical motion is generated at the end face by exciting the piezoelectric body in parallel with the torsion axis, rotational torque is generated in the rotor. It is characterized by doing. Therefore, the twin resonance type ultrasonic motor according to the present invention can be made compact with a simple structure in which an ultrasonic oscillator that generates torsional elliptical vibration is used as a stator and a rotor is crimped thereto. Therefore, there is an effect that a large output can be output for the volume, a high efficiency is obtained, and further, the rotation direction of the motor can be arbitrarily controlled by reversing the polarity of the input electric signal.

As described above, the twin resonance ultrasonic motor according to the present invention is characterized by high efficiency and high output among ultrasonic motors.
Compared with ordinary electromagnetic motors, the output per weight is large, and it is outstandingly superior in that it can obtain high output at low speed rotation. Furthermore, the angular resolution of the rotation amount is high, and it is possible to move immediately and stop instantly without inertia. The motor has excellent qualities from a practical point of view.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of a twin resonance ultrasonic motor according to the present invention, and FIGS. 2 and 3 are front views and side views of a twin resonance ultrasonic elliptical vibrator used in the motor. FIG. 4 and FIG. 5 are plan views showing modified examples of the biresonance ultrasonic elliptical transducer. 1, 31, 41 ... Twin resonator, 1 ', 31', 41 '...
… Twin resonator tip surface, 2 to 5 …… Piezoelectric vibrator, 7 …… Piezoelectric thickness vibrator, 17 …… Rotor, 21 …… Output shaft.

Claims (2)

[Claims] 1. An ultrasonic torsional oscillator having a structure in which a plurality of bending oscillators having the same resonance frequency are coupled to each other, and a torsional vibration is excited by the piezoelectric substance using another piezoelectric substance. The torsional elliptical motion is generated by exciting the rotor parallel to the torsion axis, and the rotating torque is generated in the rotor by crimping the rotor on the end face of the twin resonance type ultrasonic elliptical oscillator. Twin resonance type ultrasonic motor. 2. The twin resonance ultrasonic motor according to claim 1, wherein the polarity of the alternating voltage applied to the piezoelectric body that excites torsional vibration and another piezoelectric body that excites in parallel with the torsion axis. A bi-resonant ultrasonic motor characterized by switching the direction of rotation by changing the mutual relationship.