JPS63242183A - Cylindrical ultrasonic quadrupole motor - Google Patents

Abstract

PURPOSE:To increase torque, by welding a rotor to the side of the whole surface electrode of a quadrupole ultrasonic rotary vibrator, provided with the whole surface electrode on one surface thereof, by pressure. CONSTITUTION:A cylindrical quadrupole ultrasonic rotary vibrator 1 of a cylindrical ultrasonic quadrupole motor, which is constituted of a piezoelectric ceramics, is provided with a grounding electrode on the whole surface of the inner periphery thereof while the outer peripheral surface of the vibrator 1 is provided with quarter cylindrical electrodes 3-6. The cylinder is applied with polarizing process radially in the diametral direction previously. The vibrator 1 is fitted into a casing 10 and a rotor, equipped with a shaft, is fitted into the vibrator while the rotor 7 is supported by bearings 8, 9. According to this constitution, the center of gravity of the cylinder is rotated when a rotary electric field is impressed on said vibrator 1 and, as a result, the rotor 10 may be rotated energetically by the principle of hula-hoop.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic motor, and more particularly to an ultrasonic motor that has improved torque characteristics and can have a hollow cylindrical structure.

[Conventional technology]

The present inventor previously applied for a patent application for "center of gravity rotating type ultrasonic motor" in 1983.
No. 2-11374 was proposed. Since this motor uses an ultrasonic rotary vibrator consisting of a disk, cylinder, and ring polarized in the thickness direction as a driving source, it has the characteristic that the motor can be made thin. On the other hand, the resonant frequency, or drive frequency, is determined by the diameter of the piezoelectric element, so in high-frequency motors the diameter becomes smaller, but as the diameter becomes smaller, the area of the piezoelectric body becomes smaller, and therefore the input impedance increases, making it difficult for input to enter. However, the drawback was that it was not possible to create high-frequency, high-output motors. Furthermore, the disk type had the disadvantage that it was not possible to rotate the shaft passing through the motor or to rotate a hollow cylinder.

[Problem that the invention seeks to solve]

This invention solves the disadvantage of not being able to obtain a high-frequency, powerful motor, which the motor of the previous application had, and the problem of obtaining a structure that rotates a shaft passing through the motor or a structure that rotates a hollow shaft. The purpose is to provide superior ultrasonic motors.

[Means to solve the problem]

The cylindrical ultrasonic quadrupole motor according to the present invention is a motor that uses a separately applied "cylindrical quadrupole ultrasonic rotating vibrator" as a stator, and the electrode area can be reduced by increasing the axial length of the cylindrical vibrator. It can be made wider, the input impedance can be lowered,
Can increase resonance energy. In order to convert this strong energy into rotational force of the rotor, the rotor may be brought into external or internal contact with the outer circumferential surface or inner circumferential surface of the cylindrical vibrator, and the rotational force may be transmitted through frictional force. There are electrodes on the circumferential surface of the vibrator, but if the rotor is pressed against the ground electrode surface, it can be brought into direct contact with the electrode surface, or a wear-resistant film can be applied to the electrode surface and contact can be made through this. It's okay. If the electrode is not a ground surface, an insulating coating must be applied to the electrode on the pressure contact surface. In this respect, the quadrupole vibrator is advantageous because it has a ground electrode on the entire surface of one side of the cylinder. If the rotor is made into a hollow cylinder, it is possible to rotate the lens barrel with a strong torque.

〔Example〕

FIG. 1 and FIG. 2 are explanatory diagrams showing the principle of an embodiment of the cylindrical ultrasonic quadrupole motor according to the present invention.

A cylindrical quadrupole ultrasonic rotary vibrator 1 made of Pb (ZrTi)Os-based piezoelectric ceramic has a ground electrode applied to the entire inner peripheral surface, and further has hard chrome plating applied to the electrode surface. As shown in FIG.
．． 4, 5, and 6 are applied, and the lead wires are connected. This ceramic cylinder has been previously polarized radially in the radial direction, and the direction of polarization is such that the semi-cylindrical portion faces outward at 31.61, while the remaining semi-circumferential portion faces inward at 41.51. This cylindrical quadrupole ultrasonic rotary transducer 1 has one at each end along its length.
/10 is fitted into the casing 10, and the other part of the outer periphery of the rotary vibrator 1 has a length of 5 with respect to the casing 10.
A gap of about 0 μm is formed. The inside of the cylindrical rotary vibrator 1 has a diameter of about 38 mm, which is 10 to 50 fi smaller in diameter.
A rotor 7 with a fin and a length of 40 mm and shafts at both ends is fitted, and the shaft portion is supported by bearings 8 and 9 press-fitted into the O-sink 10. Lead wires short-circuit electrodes 1 and 5 and electrodes 4 and 6, respectively, and connect them to terminals A and B of a two-phase drive power source, respectively. The A and B terminals output sine waves with the same amplitude and frequency as the ground terminal, but with phases different by π/4, so when the lead wires are connected, a rotating electric field is generated in the cylindrical quadrupole ultrasonic rotating transducer. applied.

The frequency is the primary resonance frequency of the cylindrical rotating vibrator 1, here 4
When adjusted to 5 K fiz, the amplitude increases and the center of gravity of the cylinder rotates. As a result, according to the principle of hula hoop,
The rotor 10 rotated vigorously. The direction of rotation of the rotor 10 is reversed by reversing the early/late phase relationship between A and B.

FIG. 3 is a principle explanatory diagram showing a cylindrical rotor that also serves as a lens barrel as another embodiment of the cylindrical ultrasonic quadrupole motor of the present invention. The cylindrical quadrupole ultrasonic rotary transducer 11 set on the fixing ring 19 has the same configuration as in Example 1, so a description thereof will be omitted. The ground electrode on the inner periphery is not chrome plated, but is fitted with an aluminum cylinder with a wall thickness of 1 mm, and a thread with a pitch of 0.5 mm is carved into the inner surface, and the surface is hard chrome plated. There is. The outer periphery of the retaining ring 17 of the lens 18 is also carved with threads that fit this screw, so when the screw is fitted and the ring 17 is turned, the lens moves forward or backward on the optical axis.

Instead of rotating the link 17 by hand, a rotating electric field is applied using the method described in Example 1 and the phase is controlled to move the lens back and forth. The large torque makes it easy to drive even lens barrels with large-diameter compound lenses built in. Displacement resolution is in the micrometer range, allowing quick and fine adjustment of the focal position, and the large holding force in the set state prevents vibrations. It has the advantage of not losing focus even when other factors are added.

In the figure, 12 is a ground electrode, 13, 14, 15° and 16 are electrodes, and 19 is a fixed frame.

〔Effect of the invention〕

As explained above, in the present invention, the motor is capable of exciting first-order mode vibration along the circumference of a cylinder, and presses the rotor against the entire electrode surface side of a quadrupole ultrasonic rotary vibrator having electrodes on one surface. With this structure, the grounded rotor can be pressed against the electrode surface, which has the effect of simplifying the structure.

Furthermore, even in the case of a motor with a small diameter and a high driving frequency, the rotor length is long, so the area of the piezoelectric body is large, and it is possible to design a motor with low input impedance, and at the same time, the torque of the motor can be increased.

The rotor can be designed to be externally or internally connected to the stator, but if it is internally connected, the rotor can be shaped like a pipe, and a motor that drives the lens barrel can also be made, making it suitable for optical equipment. It has the effect of expanding its uses, such as by using it as well.

[Brief explanation of drawings]

1 and 2 are principle explanatory diagrams showing one embodiment of a cylindrical ultrasonic quadrupole motor according to the present invention, and FIG. 3 is a principle explanatory diagram showing another embodiment of the present invention. 1.11...Cylindrical ultrasonic quadrupole rotating vibrator, 2
゜12... Ground electrode, 3. 4. 5. 6.
13. 14゜15.16... Electrode, 7...
...Rotor, 8.9 ...Bearing, 10
...Casing, 17...Lens barrel, 18...Lens, 19...Fixed frame.

Claims (2)

[Claims] (1) In an ultrasonic motor that utilizes the rotational torque received through frictional force by a rotor that is crimped onto an ultrasonic rotary transducer whose center of gravity rotates, a cylindrical piezoelectric material with a zero-order breathing mode is used as an ultrasonic rotary transducer. The element consists of two areas divided by a diameter and radially polarized so that the polarities are opposite to each other. One of the outer and inner circumferential surfaces is coated with an electrode over almost the entire surface, and the other side is polarized. A cylindrical ultrasonic transducer characterized by using a cylindrical quadrupole rotating ultrasonic transducer that has electrodes divided into two along the respective circumferences in both the positive and negative regions and is capable of exciting vibrations in the first mode. Sonic quadrupole motor. (2) In the ultrasonic motor according to claim (1), the rotor is directly connected to the electrode surface of the cylindrical quadripole rotary ultrasonic vibrator on which the entire surface electrode is provided, or the rotor is provided with a cylindrical shape on the electrode surface. A cylindrical ultrasonic quadrupole motor characterized in that, when an elastic body is fitted, a cylindrical or cylindrical rotor is crimped onto the elastic body surface of the composite cylinder.