JPH0260472A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To remove the abrasion and noise of an apparatus and to improve the conversion efficiency thereof by using a waveform member for a rotor, by filling a casing for housing said rotor with a fluid, and by driving a piezoelectric material vibrator. CONSTITUTION:A casing 11, of which the inside is filled with a fluid having a high lubricating ability, is divided into two parts in the central part, and a waveform rotor 12 is housed in the inside of said casing. Said rotor 12 is formed into a shape obtained when a sine curve is caused to make a round and then closed, and a rotating shaft 13-14 is formed in the central part and supported rotatably by bearings 15-16 of the casing 11. Also, piezoelectric material vibrators 17a-17f, 18a-18f, are arranged in the casing 11 so as to face each other with the rotor 12 between. Thus, voltage is applied to one end and the other vibrators out of a pair of piezoelectric material vibrators 17, 18, so that there is a certain phase difference between said vibrators. Accordingly, the generated pressure wave of said fluid hits on the waveform rotor 12 to rotate said rotor 12.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application This invention relates to a motor using an ultrasonic vibrator. SUMMARY OF THE INVENTION The present invention provides an ultrasonic motor in which a corrugated member having a continuous corrugated portion extending around the circumference is used at least on the outer circumference of the rotor, and a casing housing the rotor is filled with fluid. This allows the rotor to rotate in the fluid, eliminating wear and noise.
Moreover, it is possible to improve the efficiency of energy conversion into rotational force.

BACKGROUND OF THE INVENTION In recent years, ultrasonic motors have been developed and put into practical use because they are capable of generating high torque at low speeds. In addition to the above-mentioned feature of generating high torque in a low speed range, this ultrasonic motor is also characterized by the fact that it does not generate a magnetic field and has good controllability.

(Nikkei Electronics, 1987, 6.15 [No,
Although the ultrasonic motor has various features as described in 2009 Problems to be Solved by the Invention -1-, the ultrasonic motor still has problems with its moving body (rotor).

An object of the present invention is to obtain an ultrasonic motor that rotates a rotor in a fluid to eliminate wear and noise.

E9 Means for Solving the Problems This invention houses a wavy rotor having a continuous wavy portion around the outer periphery in a casing filled with fluid, and the rotor is mounted on the outer wall of the casing. A plurality of pairs of piezoelectric vibrators are arranged on the circumference -L, sandwiched between them,
The rotor is rotated by periodically applying voltage to a plurality of piezoelectric vibrators, and the output shaft of the rotor is led out of the casing.

F When voltage is applied to one vibrator and the other of a pair of piezoelectric vibrators disposed with the rotor in between, the voltage is applied with a certain phase difference. This generates a fluid pressure wave or waveform that hits the rotor. At this time, since the rotor is formed into a wave shape, when the pressure wave becomes large and when it becomes small, it hits the rotor and generates a force that rotates the rotor. If a voltage is applied to the pair of piezoelectric vibrators with a predetermined phase difference, the rotor will rotate in proportion to the acceleration of the applied voltage.

G. Embodiment In explaining an embodiment of the present invention based on the drawings, first the basic principle of an ultrasonic motor will be described.

As shown in Fig. 4, a piezoelectric vibrator 2 is attached to the inner bottom surface of the bead
is installed, and the beer force 4 is filled with a liquid 5 such as water. Next, when the piezoelectric vibrator 2 is subjected to ultrasonic vibration, the liquid level 1 rises like a mountain as shown in the figure.

This is because highly directional pressure waves act due to ultrasonic vibrations. Next, this phenomenon will be applied to the configuration shown in FIG. As shown in FIG. 5, a plurality of piezoelectric vibrators 2a, 2b, 2c are arranged at equal intervals on the inner bottom surface of the bead 4 (either on a straight line or on a circumference), and the piezoelectric vibrators 2a →2b→2
An ultrasonic vibration voltage is applied to the piezoelectric vibrator with a phase difference in the order c. Then, as shown in the figure, the liquid level 3a-
→3b→3c gets excited. Incidentally, the one shown in FIG. 4 is used for atomizing water for a humidifier.

Next, as shown in FIG. 6A, the piezoelectric vibrators 2a to 2f and 2aa to 2ff are fixed to two plates 3A and 3B arranged at a constant interval in the liquid. These piezoelectric vibrators 2a
~2f and 2aa~2ff are arranged opposite to each other, and a sine curved corrugated plate 6 as shown is floated in the liquid between them.

Piezoelectric vibrators 2a, 2f and 2cc arranged in this way
, 2dd, a pressure wave is generated in the direction of the thin arrow 7 in the figure and hits the curved portion 6a of the corrugated plate 6.

This pressure wave generates a force that moves the corrugated plate 6 in the direction of the thick arrow 8. Therefore, the corrugated plate 6 moves to the position shown in FIG. 6B.

After the corrugated plate 6 has moved as shown in FIG. 6B, an ultrasonic voltage is applied to the piezoelectric vibrators 2b, 2dd, 2ee, and 2ff. The corrugated plate 6 then reaches the position shown in FIG. 6C. Similarly, when an ultrasonic voltage is applied to the piezoelectric vibrators 2C, 2ee, and 2ff, the corrugated plate 6 moves in the direction of the thick arrow 8 shown in the figure. In this way, the corrugated plate 6 is moved to the right in the figure.

Next, an embodiment of the present invention using the above basic principle will be described.

In order to make the movement of the corrugated plate 6 a continuous rotational movement, it is constructed as shown in FIGS. 1 to 3. In Figure 1, 1
1 is a casing filled with a fluid having high thermal conductivity and lubricating properties such as silicone oil, and this casing 11 is configured to be divided into two at the center. The casing 11 accommodates a corrugated rotor 12 whose details are shown in FIGS. 2 and 3. This rotor 12 has a closed shape with a sine curve going around once, and a rotating shaft 13.1/I is formed in the center, and is rotatable by sealed type bearings 15 and 1.6 provided in the casing 11. is supported by 17a to 17f and 18a to 18f are piezoelectric vibrators disposed opposite to each other in the casing 11 with the rotor 12 in between, and these vibrators +7a to +7f and 18
A to 18f are arranged at regular intervals on the circumference as shown in FIG. Note that it is more efficient to use laminated piezoelectric actuators that can generate a large force and have a large amount of displacement as the piezoelectric vibrators 178 to 17f and 18a to 18f. In addition, piezoelectric vibrators 17a~], 7f and 18a~1.
Since 8 f uses ultrasonic vibration, cavitation occurs on the transducer surface l-, so N1 or Ti plating or plate 20 is provided on the transducer surface to resist this erosion.
will be established. Numeral 19 is a screw for assembling the casing 11.

In the embodiment configured as described above, the piezoelectric vibrators 17a to 17a are rotated as follows to rotate the rotor 12.
A voltage is applied to 17d and 18a to 18f. When this voltage is applied, it is assumed that piezoelectric vibrators 17b, 18b, 17e, and 18e are located at the peaks and valleys of the rotor 12, as shown in FIG. When the piezoelectric vibrator is in such a position, the order of voltage application is as follows.

17a in the case of piezoelectric vibrators 17a to 17f.

], 7 b→17b, 17C→17c, 17
d→17d 17e->17e, 17f→1.7
f, 17a (repeated in the same manner below). In addition, in the case of piezoelectric vibrators 18a to 18f, 18
d.

18e → 18e, 18f → 18f, 18a → 18a, 1
Apply as follows: 8b→18b, 18cm", 18c, 18d (repeat in the same manner).

By applying voltages in the above order, pressure waves act on the rotor 12 as described in the basic principle, and the rotor 12
is rotated. The rotational speed at this time is proportional to the voltage application acceleration. Note that the shape of the rotor 12 may have a plurality of sine curves, or may have a waveform shape other than a precise sine curve.

Effects of Invention H As described above, according to this invention, there are no contact parts other than bearings, and the rotor rotates in fluid, so there is no wear or noise. Furthermore, since a piezoelectric vibrator is used, it generates less heat and can be made smaller and lighter. Furthermore, since the rotor can be rotated in proportion to the applied voltage acceleration, the speed of the rotor can be easily varied.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment of this invention,
FIG. 1 is a sectional view, FIG. 2 is an exploded perspective view, FIG. 3 is a plan view of the rotor, and FIGS. 4 to 6A. B and C are configuration explanatory diagrams illustrating the basic principle of the present invention.

Claims (1)

[Claims] (1) A rotor with a continuous wave-shaped part extending around the entire circumference is housed in a casing filled with fluid, and a pair of piezoelectric actuators are mounted on the inner wall of the casing with the wave-shaped part of the rotor sandwiched between them. A plurality of piezoelectric body vibrators are arranged on the circumference, a voltage is periodically applied to the plurality of piezoelectric body vibrators to rotate the rotor, and the output shaft of the rotor is guided outside the casing. Features an ultrasonic motor.