Asmo Co., Ltd.

Satoshi Morizaki

Hiroyuki Furukoshi

Yoshihiro Adachi

Kazutomo Kakegawa

Shinichi Naito

Masao Nakada

An actuator that reduces the number of components, simplifies connection, and lowers costs. The actuator includes a connector body and a cover. The connector body has an input terminal and an output terminal. The cover holds a harness with the connector body. The connector body or the cover includes a cutter that is arranged between the input terminal and the output terminal. The cutter cuts a signal line of the harness into two cut pieces when attaching the connector body and the cover to each other. The input and output terminals each include two contact portions that penetrate through a coating of the signal line of the harness to contact one of the two cut pieces of the signal line when attaching the connector body and the cover to each other.

Actuator

When a motor is driven by a signal transmitted due to a switch turned on, a count value is added. When the motor is stopped, the count value is subtracted. When the count value is an upper limit value, the motor is continuously driven until the switch is changed to an off state. Subsequently, until the count value comes to a lower limit value, the motor is maintained in a stopped state even if the switch of the motor is changed to an on state. For this reason, generation of heat in the motor can be prevented.

Driving circuit of a motor

A microcomputer outputs a driving frequency signal to an oscillator circuit and the oscillator circuit oscillates at a driving frequency designated by the microcomputer. A switching control circuit outputs switching signals to an A-phase amplifier circuit and to a B-phase amplifier circuit at a predetermined timing. The A-phase amplifier circuit and the B-phase amplifier circuit each convert a DC voltage supplied by a voltage control circuit to an AC voltage and supply the same to two piezoelectric bodies of an ultrasonic motor. Due to the AC voltage being supplied to each of the two piezoelectric bodies, the ultrasonic motor is driven. At the start time of driving the ultrasonic motor, by gradually increasing the voltage level of the DC voltage outputted from the voltage control circuit and also gradually increasing the voltage level of a driving voltage to be supplied to the piezoelectric body of the ultrasonic motor, a stator and a rotor of the ultrasonic motor are gradually separated from each other. Further, in a case in which the voltage has been increased to a predetermined voltage level, the driving frequency is gradually lowered to increase the number of revolutions of the motor, thereby making it possible to lessen the vibration of the ultrasonic motor at the start time of driving. As a result, the generation of an audible sound can be prevented.

Growing community of inventors

Toyokawa, Japan

Satoshi Morizaki