Toshiharu Ogasawara

Construction of Ultrasonic Motors and their Application

This paper deals with construction of an ultrasonic motor and their application; a paper-sending device using a flat rectangular type ultrasonic motor is described. Various types of ultrasonic motors can be constructed by considering displacement combinations in the horizontal and vertical directions at the elliptic motion yielded. As for this elliptic motion, multi-mode vibrators using degenerate modes of the same or different form are utilized.

Ultrasonic Motors Using Piezoelectric Ceramic Multi-Mode Vibrators

The purpose of this paper is to report development of an ultrasonic motor using piezoelectric ceramic multi-mode vibrators of circular or annular plates, in which degenerate horizontal vibration modes of the same or different form are used. Some constructions of the motor and its experimental characteristics are presented. The ultrasonic motor investigated herein shows special merit in its thin construction.

Experimental Characteristics of a Bolt-Clamped Short-Cylindrical Torsional Vibrator Using Shear Mode Piezoceramics Inserted in the Axial Direction.

A torsional vibrator using shear mode piezoceramics inserted in the axial direction, developed 20 years ago for use in a mechanical filter exhibits good vibration performance. The authors applied this torsional vibrator to a high-power transducer shaped as a short cylinder with a large diameter. In this case, the torsional vibrator can easily be fabricated by bolt-clamping in the radial direction, and the small number of parts is beneficial to the fabrication. The vibrational characteristics of the torsional vibrator were determined previously using finite element analysis. In this paper, we report the results of a trial fabrication of such a torsional vibrator. As a result, it is clarified that this torsional vibrator exhibits superior vibration performance such that it could be applied to an ultrasonic high-power transducer, and that the torsional and bending vibrations on the disk are easy to couple to each other according to the dimensions of the vibrator.

Fundamental Considerations of Excitation of a Flexural Progressive Wave and its Application

This paper deals with fundamental considerations of excitation of a flexural progressive wave and its application to an ultrasonic motor. The conditions for excitation of a progressive wave not only in a straight line flexurally vibrating medium, but also in a flexural disk vibrator are made clear, and conditions of the excitation method for an ultrasonic motor are reported to be very similar to those for an electro-magnetic induction motor. Characteristics of a disk vibrator for an ultrasonic motor and results of fundamental experiments on it are also described.

Ultrasonic Motor Using a Large-Diameter Torsional Vibrator with Slant Slits

This paper deals with a large-diameter rod-type ultrasonic motor, in which only the torsional vibration is excited piezoelectrically. This new motor is designed to improve the performance of a relatively high-torque motor by increasing the diameter of the stator vibrator. The characteristic feature of the motor construction is that many slits are cut aslant on the vibrator end-face in contact with a rotor in order to form small slanted cantilever beams ; that is, these cantilever beams operate in the bending vibration due to coupling with the main torsional vibration of the stator and lift the rotor in the inclined direction to rotate it. Therefore, this motor operates fundamentally one-way, and thus its advantage is that it is easily driven with a single power source. The first part of this paper concerns the simulated results of an aslant slit torsional vibrator, especially on its slanted cantilever beam, and the second part describes the experimental investigation of the prototype motor.

Characteristics and a New Control Method of a Same-Phase Drive-Type Ultrasonic Motor

This paper deals with a same-phase drive-type ultrasonic motor, using two degenerate bending vibration modes of a disk. Characteristics of the motor driven at low input power are shown. Signal waves picked up from a rotor are also shown. It is found that these signals are closely related to revolution states of the motor. Moreover, a new control method for the motor is proposed and tried.

Ultrasonic linear motors for application to driving a light pick-up element

This paper deals with ultrasonic linear motors using a double-mode vibrator and their application to driving a light pick-up element of CD-ROM etc. We have already invented some ultrasonic linear motors. In the first part of this paper, two kinds of the motors using a square plate vibrator are proposed; one construction is the motor using an extensional mode and a bending mode, and the other is using degenerated bending modes of the same form. Their construction and characteristics are shown. The second part contains experimental investigation of the linear motor using a L1-B2 mode rectangular plate. Characteristics of the device of which a light pick-up element is mounted on a linear motor are presented

Constructions and characteristics of ultrasonic motors using a piezo-ceramic annular plate

Ultrasonic motors that use a piezoceramic annular plate vibrating in nonaxisymmetric modes are discussed. Analyses on nonaxisymmetric vibration modes of an annular plate are summarized from the viewpoint of its application to an ultrasonic motor. An attempt was made to construct the motors using the annular plate, and the characteristics of the motors were measured. Experimental results of motors utilizing degenerated mode rotation of

Vibratory gyro‐sensor using a trident tuning fork resonator with lateral width set in parallel with a rotationary axis

This paper deals with a new type of piezoelectric vibratory gyro‐sensor using a trident tuning fork resonator, which is supported laterally at its base portion, the width direction of which is in parallel with a rotationary axis. The vibratory gyro‐sensor is an important and attractive device as an angular velocity sensor, especially, in the vehicle stability control (VSC) system schemed for a practical use in the not so far future. Therefore, many researchers have been engaged in development of such a key device in the VSC system. Some types of piezoelectric vibratory gyro‐sensors have also been investigated; for example, two types of vibratory gyro‐sensors have been studied using a trident tuning fork resonator: one of them was vertically supported at its base portion and the other was flatly supported at the same portion. The gyro‐sensor dealt with here is one of such types of gyro‐sensors; however, its operation principle is different from theirs. That is, this new gyro‐sensor is aimed at being constr...

EXCITATION OF UNIFORM FLEXURAL PROGRESSIVE WAVES ON A LARGE RECTANGULAR PLATE

A method for exciting a uniform flexural progressive wave which propagates along the length of a large rectangular duralumin plate is proposed. A method for modal vibration control of large ultrasonic tools is applied for both uniform excitation and absorption of the progressive wave at the ends of the plate. In the experiment, a small weight placed on the plate 10 mm thick has moved slowly towards the source of vibration. This fact indirectly proves the existence of the progressive waves excited by the method. However, standing waves of some strength has also been found and the progressive wave does not seem completely uniform. The authors conclude that the method proposed here still has some practical problems to be solved and further investigation is necessary.