Takehiro Takano

Thin Rotary and Linear Ultrasonic Motors Using a Double-Mode Piezoelectric Vibrator of the First Longitudinal and Second Bending Modes

This paper deals with thin rotary and linear ultrasonic motors using a double-mode piezoelectric ceramic vibrator; a rectangular plate vibrator of the first longitudinal and second bending modes is utilized. A specific merit of the motors is that their thickness can meet the restriction of 10 mm, which is one of the practical requirements of a light load gearless motor. The rotary motor is intended for application in card forwarding, and the linear motor, in magnetic-head traveling and so on. Construction and characteristics of the motors are described herein.

Analysis of nonaxisymmetric vibration mode piezoelectric annular plate and its application to an ultrasonic motor

The development of an ultrasonic motor using nonaxisymmetric vibration modes of a piezoelectric annular plate is described. A piezoelectric annular plate is analyzed to find its mode patterns, elliptic motions of displacement for the motor, and the distributions of the induced charge on the plate surface, and to calculate electromechanical coupling factors. On the basis of the analyzed results, motors using the annular plate have been built and their characteristics measured. The construction and characteristics of these motors are discussed.<<ETX>>

Ultrasonic Motors Using Longitudinal and Bending Multimode Vibrators with Mode Coupling by Externally Additional Asymmetry or Internal Nonlinearity

The present paper deals with some ultrasonic motors using longitudinal and bending multimode vibrators with their mode couplings caused by externally additional asymmetry or internal nonlinearity. A rectangular plate vibrator with two corners on one diagonal line cut to make its resonance modes couple with each other was used, along with a rectangular plate vibrator under the condition that two resonance frequencies are obtained, for example, as fL/fB=2.0, because internal nonlinear coupling of parametric vibration between two resonance modes is generated under this condition. Using these vibrators with mode couplings, it was found that some ultrasonic motors of simple form can be constructed. The ultrasonic motor using the phenomenon of mode-coupling vibrations dealt with here is not completely new, and a few trial constructions have already been reported [Jpn. J. Appl. Phys. 24 (1985) Suppl. 24-2, p. 739]. However, their motions were not reversible in ordinary driving with an electrical signal of a constant frequency. In contrast, the motors that the authors proposed in this paper can be expected to have a reversible motion.

Some constructions and characteristics of rod-type piezoelectric ultrasonic motors using longitudinal and torsional vibrations

Ultrasonic motors using longitudinal and torsional motions of rod vibrators have previously been proposed. Several motor constructions, whose forms are different from the previous ones, are proposed and their characteristics are experimentally examined in order to develop the ultrasonic motors of this type; that is, they are expected to have much different uses, according to how their forms are modified. Two groups of motor are dealt with: one contains motors basically suited to the relatively high torque of 2-3 kgf-cm and the other contains motors for small or medium torque below about 1.0 kgf-cm. As the result, operational characteristics of motors are totally revealed. These are useful in developing the rod type ultrasonic motors and in their practical applications.<<ETX>>

Same phase drive-type ultrasonic motors using two degenerate bending vibration modes of a disk

Same-phase drive-type ultrasonic motors, using two degenerate bending vibration modes of a disk, are presented. The distinctive feature of the motor is in using the standing wave modes. The motor is not driven by two input signals with different phases, but by input signals with the same phase. Therefore, only one amplifier is sufficient to drive the motor. The experimental results have proved that the motor can yield stable operational characteristics at low speed and high torque.<<ETX>>

Examination of disk-type multidegree-of-freedom ultrasonic motor

A multidegree-of-freedom (MDOF) ultrasonic motor using the multimode of a disk vibrator is realized. A spherical rotor can rotate around arbitrary axes. However, at the beginning of research on the MDOF ultrasonic motor, the MDOF ultrasonic motor did not have any mechanisms for supporting a spherical rotor. Since the preload was given by only the rotors own weight, the friction between the rotor and the stator vibrator was very small, but the torque characteristics of the MDOF motor were insufficient for practical use. The purpose of this study is to improve the motor performance further. In this paper, some support and preload mechanisms using a support plate were examined for the improvement of the motor performance. In addition to these methods, a sandwich structure in which two stator vibrators hold a spherical rotor is proposed. This structure has both a rotor support mechanism and a preload mechanism, and high torque by the torque composition of two stator vibrators can be obtained.

Excitation of a progressive wave in a lossy ultrasonic transmission line and an application to a powder-feeding device

This paper describes several excitation methods of a progressive wave in an ultrasonic lossy transmission line and its application to powder-feeding devices. The use of a lossy transmission line causes the reflected wave to reduce in magnitude. Therefore, the wave, transmitted from the driving source, becomes dominant in the line. That is, the progressive wave is generated, without attention to acoustical matching in the received end. A symmetric mode, an asymmetric mode and a rotating asymmetric mode were used for the progressive wave and an acrylic pipe was appropriated for the ultrasonic lossy line. Construction and characteristics of a trial device are shown. It was found that the device is useful for feeding and supplying a small amount of powder.

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.

Linearly Moving Ultrasonic Motor Using a Multi-Mode Vibrator

This paper deal with the construction and some of the characteristics of linearly moving ultrasonic motors using multi-mode vibrators; a thin rectangular plate vibrator of the 1st longitudinal and 4th bending modes, and a piezo-ceramics annular plate vibrator of the 1st radial and ((1, 1)) non-axisymmetric modes are utilized. Key points in the design of the multi-mode vibrators and experimental characteristics of the motor such as its efficiency are discussed.

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.