Elastic body for actuator, and piezoelectric actuator

Abstract

An elastic member 43 comprises a crystalline resin. The elastic member is fixed to a piezoelectric element 42 that generates vibration in response to application of an AC voltage, is in contact with a movable body 45 in use, and flexurally vibrates in response to the vibration of the piezoelectric element 42 to drive the movable body 45. The elastic member 43 may have a tooth 43b on an opposite side with respect to a side fixed to the piezoelectric element 42. The crystalline resin may be a poly(aryl ketone) resin or a poly(phenylene sulfide) resin. The piezoelectric actuator has an excellent transmission of flexural vibration. In a case where a displacement expansion element of a displacement-expanding piezoelectric actuator is formed from a crystalline resin, the actuator greatly amplifies an expansion and contraction displacement of a piezoelectric element. In a case where a resonance member of a Langevin transducer is formed from a crystalline resin, the transducer allows the vibration of the surface at a high speed even in application of a low electric current (or a low voltage).

Description

technical field [0001] The present invention relates to an elastic body for an actuator using ultrasonic vibration generated by an electromechanical conversion element such as a piezoelectric element, and a piezoelectric actuator including the elastic body. Background technique [0002] An ultrasonic motor is known as a piezoelectric actuator using a piezoelectric element. An ultrasonic motor is a motor that uses a piezoelectric element as an electromechanical conversion element as an ultrasonic vibrating body. Compared with electromagnetic motors, ultrasonic motors do not require coils, have a simple structure, and have excellent responsiveness and controllability at low speeds and high torques, and can perform small and precise drives. Therefore, they are widely used in optical devices such as cameras and DVDs. . Among ultrasonic motors, there are linear or rotary types, and convert ultrasonic vibration from a vibrating body into linear motion or rotary motion. [0003]...

AI Technical Summary

Problems solved by technology

However, the elastic body made of metal has a heavy specific gravity and is hard, so it also has the following disadvantages: its own vibration is low, the formability is low, it is not easy to miniaturize, and the productivity is reduced for complex shapes such as comb teeth. Deterioration due to rust, difficult to improve characteristics by compounding additives, etc., insulation cannot be ensured, etc.

However, since the elastic body made of metal has a heavy specific gravity and is hard, it has the following disadvantages: its own vibration is low, the formability is low, it is not easy to miniaturize, and the productivity decreases in complex shapes with protrusions. It leads to deterioration, it is difficult to use additives to improve characteristics, and insulation cannot be ensured, etc.

[0030] However, in the ultrasonic vibrators of Patent Documents 7 to 10, the vibration velocity of the surface is low, and the output characteristics are not sufficient.

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