JPH0336971A - Ultrasonic motor - Google Patents

Abstract

PURPOSE:To obtain the rotational motion of a rotor by providing a hollow cylindrical stator, which is in perturbed motion and of which the inside is magnetized so that poles differ alternately in the circumferential direction, and a cylindrical rotor, of which the outside is magnetized alternately in the circumferential direction and the number of poles slightly differs from that of the stator. CONSTITUTION:A plurality of piezoelectric actuators 3 are provided between circular tube-shaped frame 1 and stator 2 to extend and contract radially by an applied voltage. The stator 2 is composed of ferromagnetic material, its inside is magnetized into alternately different poles, and the poles are nine in number. The outside of a rotor 4 is also composed of ferromagnetic material and magnetized into N and S poles alternately in the same way as the stator 2, and the number of poles is eight which is one less than that of the stator 2. Thus, it is possible to perform the rotational motion of the rotor 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a so-called ultrasonic motor that extracts the deformation of a piezoelectric element due to electric JE as rotational motion.

[1; t: Future technology J Conventional ultrasonic motors (J) used two types of piezoelectric elements to generate rotational force on the rotor with 11 forces.

[Problems to be Solved by the Invention] The conventional technology described in the prior art has a drawback that the torque decreases due to wear because the five-speed power transmission is performed by friction.

[Means for Solving the Problems] In order to achieve the above object, the present invention combines a plurality of piezoelectric actuators, and
A hollow cylindrical stator whose inner side is R-magnetized so that the poles are alternately different in the circumferential direction, which perturbs the locus of one point in a circular manner when viewed from the center line direction, by adding different mills. A cylindrical shape whose central shaft is supported by a bearing, a part of which is always inscribed in the stator with a gap, and whose outer side is alternately magnetized in the circumferential direction so that the number of poles differs by one degree from the stator. It has a rotor, and is configured so that the rotor is rotated by the perturbation movement of the stator.

[Effects of the Invention] Since it is configured as described above, Jfi defects do not occur in the power transmission part like in the conventional ultrasonic motor. There are a plurality of piezoelectric actuators 3 between the flares AL and the stator 2, which expand and contract in the radial direction depending on the applied voltage. /+ In the case of a piezoelectric actuator with 8 views as shown in the figure, if a delayed rectangular wave of f-L[+ is applied at 1/8 increments in the 0 meter direction as shown in Figure 2, the stator 2 will become as shown in 314. The position changes as shown in 2-1.2-2.2-3.2-4, and the stator inscribed curve becomes cylindrical. , it U4 and J], and the central axis 5 of the rotor 4 is rotatably supported by a bearing integrally provided with the rotor 4, which is slightly smaller than the diameter of this cylinder.

The stator 24i is made of ferromagnetic material, and its inner side is alternately attached to different poles. The N-shaded part is the S pole. The number of LJ poles in Japan is 9, and the outside of the rotor 4 is also made of ferromagnetic material.

Similar to stator 2, it is alternately magnetized with N, Sl, and 1 m@. The number of poles is 8, which is one less than the stator 2.

Now, from the 111th position 4, a delayed voltage Ts is applied clockwise to the actuator 3 (Then, the small gap M between the stator 2 and the rotor 4 moves clockwise. At 11° C., the rotor 11 rotates counterclockwise due to the force that increases to the deviation [i] between the stator 2 and the rotor 1.

[Effect of the Invention J] Since the present invention is configured as described above, the displacement caused by the voltage of the piezoelectric actuator 2 can be effectively converted into rotational motion, and the transmission of rocking motion by I'll friction can be achieved. Since there is no change in torque over time, the lifespan is the same as that of conventional motors.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the principle of the ultrasonic motor of the present invention, FIG. 2 is a voltage applied to the piezoelectric actuator 2, and FIG. 3 is a diagram showing the locus of the stator 2 caused by the piezoelectric actuator 2. 1... Frame 11. 2... Stator, 3... J, E
IT-type actuator, ・4... Rotor 5... Rotor center axis" = a [L- Procedural amendment writing method) 1. Display of case 1999 Patent application No. 169883 2. Title of invention Ultrasonic motor 3 , Relationship to the case of the person making the amendment Patent applicant address: 3-2-12-407 Sugamo, Toshima-ku, Tokyo October 31, 1999 5. Subject of amendment Drawings (all drawings) 6. Contents of amendment (attached sheet) street)

Claims (1)

[Claims] By combining multiple piezoelectric actuators and applying voltages with different phases to them, the locus of one point makes a perturbed movement in a circular manner when viewed from the center line direction, and poles alternate in the circumferential direction. A hollow cylindrical stator is magnetized differently, and its central axis is supported by a bearing, and a part of the stator is always inscribed in the stator with a slight gap, and the outside is alternately circumferentially and slightly separated from the stator. An ultrasonic motor that has a cylindrical rotor magnetized with different numbers of poles and rotates the rotor by perturbing the stator.