JP2006081236A5

JP2006081236A5 -

Info

Publication number: JP2006081236A5
Application number: JP2004259319A
Authority: JP
Filing date: 2004-09-07
Publication date: 2007-10-18
Anticipated expiration: 2024-09-07

Claims

A drive circuit for driving an ultrasonic motor including a piezoelectric element that expands and contracts by application of an alternating voltage and a vibrating body having a contact portion that comes into contact with a driven body,
Pulse generation means for generating a periodic pulse signal ;
While maintaining the period of the pulse signal generated by said pulse generating means, and the pulse number adjustment means for adjusting the number of pulses in the unit period of the pulse signal generated by said pulse generating means,
Applies a first amplitude of the AC voltage that corresponds to the adjusted pulse signal by the pulse number adjustment means to said piezoelectric element, said first time period that the alternating voltage amplitude is applied to said piezoelectric element and in non-overlapping time periods, applying a smaller second amplitude of the AC voltage from the AC voltage of the first amplitude that corresponds to the generated pulse signal amplitude by the pulse generating means to the piezoelectric element, the greater Driving means for driving the sonic motor,
An ultrasonic motor driving circuit configured to control the driving of the ultrasonic motor by adjusting the number of pulses in the unit period by the pulse number adjusting means.

A drive circuit for driving an ultrasonic motor including a piezoelectric element that expands and contracts by application of an alternating voltage and a vibrating body having a contact portion that comes into contact with a driven body,
  Pulse generating means for generating a periodic pulse signal;
  A pulse number adjusting means for adjusting the number of pulses within a unit period of the pulse signal generated by the pulse generating means while maintaining the period of the pulse signal generated by the pulse generating means;
  Driving means for driving the ultrasonic motor by applying an AC voltage corresponding to the pulse signal adjusted by the pulse number adjusting means to the piezoelectric element;
  An ultrasonic motor driving circuit configured to control the driving of the ultrasonic motor by adjusting the number of pulses in the unit period by the pulse number adjusting means.

The ultrasonic motor drive circuit according to claim 1, wherein the second amplitude is substantially half of the first amplitude.

The driving means further includes voltage reduction means for reducing the supplied voltage, and the voltage reduction is performed in a time zone that does not overlap with a time zone in which the alternating voltage having the first amplitude is applied to the piezoelectric element. The voltage reduced by the means is applied to the piezoelectric element substantially in synchronization with the pulse signal generated by the pulse generation means, and an AC voltage obtained by adding the voltage reduced by the voltage reduction means is The drive circuit for an ultrasonic motor according to claim 1, wherein the AC voltage has the second amplitude.

The ultrasonic motor drive circuit according to claim 4 , wherein the amplitude of the AC voltage before the voltage reduced by the voltage reduction unit is added is substantially half of the first amplitude.

The ultrasonic motor driving circuit according to claim 4 , wherein the voltage lowering unit is a resistor.

It said voltage drop means is a variable resistor capable of changing the resistance value, the movable by changing the resistance value of the variable resistor, according to claim 4 or 5 is configured capable of changing the second amplitude Ultrasonic motor drive circuit.

The ultrasonic motor drive circuit according to claim 1, further comprising unit period setting means for setting the unit time.

The ultrasonic motor according to any one of claims 1 to 8 , wherein the unit period setting unit is configured to set a period that is a multiple of a period of a pulse signal generated by the pulse generation unit as the unit period. Drive circuit.

Driving circuit of the ultrasonic motor according to any one of claims 1 is configured capable of changing the unit period 9.

The pulse number adjusting means invalidates a part of the pulse signals generated by the pulse generating means to thereby reduce the number of pulses in the unit period of the pulse signal generated by the pulse generating means. driving circuit of the ultrasonic motor according to any one of 10 claims 1 and is configured to regulate.

By adjusting the number of pulses in the unit period by the pulse number adjustment means, wherein according to any one of claims 1 to 11 is configured to perform a current control for adjusting the current value of the ultrasonic motor super Drive circuit for sonic motor.

Current detecting means for detecting the current of the ultrasonic motor;
Current adjusting means for adjusting the current of the ultrasonic motor;
The current adjusting means operates the pulse number adjusting means based on a current command value and a detection result of the current detecting means to adjust the number of pulses in the unit period, thereby enabling the ultrasonic motor to driving circuit of the ultrasonic motor according to any one of claims 1 and is configured to perform current control for adjusting the current 11.

The driven body is a rotor provided rotatably,
The ultrasonic wave according to any one of claims 1 to 13 , wherein the number of pulses in the unit period is adjusted by the number-of-pulses adjusting means to control the number of rotations of the rotor. Motor drive circuit.

The driven body is a rotor provided rotatably,
A rotational speed detection means for detecting the rotational speed of the rotor;
A rotation speed adjusting means for adjusting the rotation speed of the rotor;
The rotational speed adjusting means operates the pulse number adjusting means based on the rotational speed command value and the detection result of the rotational speed detecting means to adjust the number of pulses in the unit period, thereby allowing the rotor to adjust. driving circuit of the ultrasonic motor according to any of claims is configured to perform the speed control section 1 to 13 for adjusting the rotational speed of the.

The ultrasonic motor drive circuit according to any one of claims 1 to 15 ,
And an ultrasonic motor driven by the drive circuit.

The actuator according to claim 16 , wherein the driven body is in contact with a contact portion of the ultrasonic motor and is displaced by a driving force from the ultrasonic motor.