Vibration wave motor
AssigneeCanon Kabushiki Kaisha
InventorsNobuyuki Suzuki, Masao Shimizu, Mitsuhiro Katsuragawa
Life of this patent
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Abstract
A vibration wave motor for driving a movable member by a travelling vibration wave generated by applying a periodic signal to an electro-mechanical energy transducer element such as an electrostrictive device or piezoelectric device is disclosed. A drive status of the vibration wave motor is detected, a phase difference between the detected signal and the periodic signal applied to the transducer element is detected, a frequency of the periodic signal is selected such that the phase difference is equal to a predetermined constant and the vibration wave motor is driven in a resonance state.
Claims53
A control circuit for a vibration wave motor having first and second electro-mechanical energy transducing elements arranged on a vibration member for generating a travelling vibration wave by applying periodic signals respectively having phases different from each other to said first and second energy transducing elements for use as a drive force, comprising:
- (a) first detection means for detecting an output signal of an electro-mechanical energy transducing element which is arranged on said vibration member and to which said periodic signals are not applied;
- (b) second detection means for detecting a phase shift of the phase difference between the output signal detected by said first detection means and said periodic signals, from a predetermined phase;
- and
- (c) a frequency determination circuit for determining a frequency of the periodic signals applied to said first and second transducing elements in accordance with the phase shift detected by said second detection means;
- said predetermined phase being determined in accordance with a position al relationship between the transducing element to which the periodic signals are applied and the transducing element which produces the output signal.
A control circuit for a travelling vibration wave motor for driving a movable member by a travelling vibration wave generated by applying a periodic voltage to an electro-mechanical energy transducing element, comprising:
- (a) a pulse signal generation circuit for generating a pulse having a predetermined repetition period;
- and
- (b) an electrode for applying said pulse to an electro-mechanical energy transducing element through a coil.
A control circuit for a travelling vibration wave motor for moving a member by a travelling vibration wave generated by applying periodic signals which respectively have phases different from each other to first and second electro-mechanical energy transducing element parts comprising:
- (a) detecting means for detecting a drive state of the motor driven by the travelling vibration wave and producing a periodic signal representing the drive state of the motor;
- (b) a detection circuit for detecting a phase difference between the periodic signal from said detecting means and the periodic signal applied to said first electro-mechanical energy transducing element part.
A vibration wave motor comprising;
- (a) vibration member having first and second electro-mechanical energy transducing element parts arranged thereon;
- (b) application means for applying periodic signals which respectively have phases different from each other to said first and second electro-mechanical energy transducing element parts to generate a travelling vibration wave as a drive force;
- (c) detection means for detecting a signal produced by another electron-mechanical energy transducing element part arranged on said vibration member at a position electrically insulated from said application means;
- (d) a detection circuit for detecting the phase difference between a periodic signal applied to said first transducing element part and the signal detected by said detection means;
- and
- (e) a frequency determination circuit for determining the frequency of the periodic signals applied to said first and second electro-mechanical energy transducing element parts in accordance with the phase difference detected by said detection circuit.
A control circuit for a travelling vibration wave motor for moving a member by a travelling vibration wave generated by applying periodic signals which respectively have phases different from each other to first and second electro-mechanical energy transducing element parts, comprising:
- (a) detecting means for detecting a drive state of the motor driven by the travelling vibration wave and producing a periodic signal representing the drive state of the motor;
- (b) a detection circuit for detecting a phase difference between the periodic signal from said detecting means and the periodic signal applied to said first electro-mechanical energy transducing element part and for detecting the phase shift between the detected phase difference value and a predetermined phase difference;
- and
- (c) a frequency control circuit for controlling the frequency of the periodic signals applied to said first and second electro-mechanical energy transducing element parts to reduce the phase shift detected by said detection circuit.
A vibration motor comprising:
- (a) a vibration member having first and second electro-mechanical energy transducing element parts arranged thereon;
- (b) application means for applying periodic signals having different phases from each other to said first and second electro-mechanical energy transducing element parts, to generate a travelling vibration wave as a drive force;
- (c) detection means for detecting a signal produced by another electro-mechanical energy transducing element part arranged on said vibration member at a position electrically insulated from said application means;
- (d) a detection circuit for detecting a phase difference between the periodic signal from said detecting mean and the periodic signal applied to said first electro-mechanical energy transducing element part and for detecting the phase shift between the detected phase difference and a predetermined phase difference;
- (e) a frequency control circuit for controlling the frequency of the periodic signals applied to said first and second electro-mechanical energy transducing element parts to reduce the phase shift value detected by said detection circuit.
A vibration wave motor comprising:
- (a) a vibration member;
- (b) a first group of electro-mechanical energy transducing elements and a second group of electro-mechanical energy transducing elements arranged at different positions on said vibration member;
- (c) first and second application means for applying periodic signals at different phases to said first and second groups of electro-mechanical energy transducing elements to generate a travelling vibration wave as a drive force;
- (d) an electro-mechanical energy transducing element arranged at a different position on said vibration member from said first and second groups of electro-mechanical energy transducing elements for producing a periodic signal representing a vibration state of the travelling vibration wave;
- (e) a frequency determination circuit for determining the frequency of the periodic signals applied to said first and second group of electro-mechanical energy transducing elements through said application means in accordance with the phase difference between the periodic signal applied to said first group of electro-mechanical energy transducing elements and the periodic signal representing the vibration state so that the phase difference is maintained at a specified value.
A vibration motor device comprising:
- (a) a vibration member having first and second electro-mechanical energy transducing element parts arranged thereon;
- (b) application means for applying periodic signals having different phases from each other to said first and second electro-mechanical energy transducing element parts, to generate a travelling vibration wave as a drive force;
- (c) detecting means for detecting the drive state of said motor driven by the travelling vibration wave and producing a periodic signal representing the drive state of the motor;
- and
- (d) a detection circuit for detecting the phase difference between the periodic signal from the detecting means, the periodic signal applied to said first electro-mechanical energy transducing element part and the resonance vibration state of the motor being monitored by detecting the phase difference with said detection circuit.
Dependencies are inferred from the claim text.