| 摘要 |
PURPOSE:To obtain a piezoelectric material, the amplitude of vibration of which can be large in the case of inputting an AC field of a frequency in the vicinity of the resonance frequency of a piezoelectric body, by baking the starting piezoelectric material mixed with resin to remove the resin material, and obtaining a dielectric material as the piezoelectric material of high porosity. CONSTITUTION:A starting piezoelectric unit containing at least one kind selected from a group consisting of lead zirconate titanate, lead titanate and barium titanate, is mixed with methacrylic resin powder, and this mixture is baked to produce a porous dielectric material by substantially removing the resin material. An ultrasonic motor is constituted of a piezoelectric body 1 made of this porous dielectric material, a vibrator 2 mounted onto the piezoelectric body 1, a mover 4 provided n the vibrator 2 through a friction material 3, a rotary shaft 5 journalled to the center of the mover 4 and electrode parts 6 provided on both sides of the piezoelectric body 1. Since the amplitude of vibration of the piezoelectric body 1 depends upon its porosity, large amplitude can be obtained by this porous material. |
