US5004965A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brushless motor with torque compensation
Assignee: Canon Inc
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Filing: 1988-05-18
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Granted: 1991-04-02
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Expires: 2008-05-18
Abstract
Abstract There is disclosed a brushless motor provided with a speed detector for detecting the rotating speed of rotor; a synthesizer for synthesizing the output wave forms of inverse electromotive force of different phases of the brushless motor; a detector for detecting the synthesized wave form from the synthesizer; an inverter for inverting the detected wave form from the detector; an oscillator for generating a predetermined frequency; a frequency divider for dividing the frequency from the oscillator according to the output from the inverter; a counter for counting the clock output signal from the frequency divider, latching the count in a cycle of a signal from the speed detector and resetting the count; and a drive controller for generating a control voltage in response to the output from the counter thereby controlling the current supplied to the rotor.
Inventors
- 👤 Mitsuhiro Otokawa
- 👤 Hiroyuki Takimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:17
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/10
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
153 words
In a brushless motor which includes a rotor, comprising: speed detecting means for detecting the rotating speed of said rotor; synthesizing means or synthesizing the output wave forms of inverse electromotive forces of different phases of the brushless motor and outputting a synthesized wave form; detector means for demodulating the synthesized wave form obtained from said synthesizing means and outputting a demodulated wave form; inverter means for inverting the demodulated wave form from said detector means and outputting it; comparator means for comparing a predetermined rotation speed with the speed detected by said speed detecting means and generating a voltage corresponding to the difference of speed obtained from said comparison and outputting it; adding means for adding the output from said inverter means to the output from said comparator means and outputting it; and drive control means for controlling the current supplied to said motor according to the output from said adding means.
Claim 2
Dependent Claim
153 words
In a brushless motor which includes a rotor, comprising: speed detecting means for detecting the rotating speed of said rotor; synthesizing means or synthesizing the output wave forms of inverse electromotive forces of different phases of the brushless motor and outputting a synthesized wave form; detector means for demodulating the synthesized wave form obtained from said synthesizing means and outputting a demodulated wave form; inverter means for inverting the demodulated wave form from said detector means and outputting it; comparator means for comparing a predetermined rotation speed with the speed detected by said speed detecting means and generating a voltage corresponding to the difference of speed obtained from said comparison and outputting it; adding means for adding the output from said inverter means to the output from said comparator means and outputting it; and drive control means for controlling the current supplied to said motor according to the output from said adding means.
Claim 3
Dependent Claim
166 words
In a brushless motor which includes a rotor, comprising: speed detecting means for detecting the rotating speed of said rotor and outputting it; synthesizing means for synthesizing the output wave forms of inverse electromotive forces of different phase of the brushless motor and outputting a synthesized wave form; detector means for demodulating the synthesized wave form obtained from said synthesizing means and outputting it; inverter means for inverting the demodulated wave form from said detector means and outputting it; oscillator means for generating a predetermined frequency signal; frequency divider means for dividing the predetermined frequency signal from said oscillator means according to the output from said inverter means; counter means for counting the output from said frequency divider means as clock signals, latching the count in the counter means when a predetermined signal is entered from said speed detecting means, and simultaneously resetting the count value; and drive control means for controlling the current supplied to said motor, according to the output from said counter means.
Claim 4
Dependent Claim
166 words
In a brushless motor which includes a rotor, comprising: speed detecting means for detecting the rotating speed of said rotor and outputting it; synthesizing means for synthesizing the output wave forms of inverse electromotive forces of different phase of the brushless motor and outputting a synthesized wave form; detector means for demodulating the synthesized wave form obtained from said synthesizing means and outputting it; inverter means for inverting the demodulated wave form from said detector means and outputting it; oscillator means for generating a predetermined frequency signal; frequency divider means for dividing the predetermined frequency signal from said oscillator means according to the output from said inverter means; counter means for counting the output from said frequency divider means as clock signals, latching the count in the counter means when a predetermined signal is entered from said speed detecting means, and simultaneously resetting the count value; and drive control means for controlling the current supplied to said motor, according to the output from said counter means.
Claim 5
Dependent Claim
150 words
In a brushless motor comprising: speed detecting means for non-linearly detecting a speed of a rotor, said speed detecting means including a speed detecting magnet having magnetic poles for a frequency generator and provided on a periphery of said rotor, and a magnetic resistance device for detecting magnetic fields of said magnetic poles, said magnetic poles being spaced from each other in accordance with a pattern of torque ripple, denser at the position of higher torque and coarse at the position of lower torque; comparator means for comparing a predetermined rotating speed with the speed detected by said speed detecting means and converting the difference between said speeds obtained by the comparison into a voltage value corresponding to the difference between said speeds, and outputting the voltage value; and drive control means for controlling current supplied to the motor on the basis of the voltage value from said comparator means.
Claim 6
Dependent Claim
150 words
In a brushless motor comprising: speed detecting means for non-linearly detecting a speed of a rotor, said speed detecting means including a speed detecting magnet having magnetic poles for a frequency generator and provided on a periphery of said rotor, and a magnetic resistance device for detecting magnetic fields of said magnetic poles, said magnetic poles being spaced from each other in accordance with a pattern of torque ripple, denser at the position of higher torque and coarse at the position of lower torque; comparator means for comparing a predetermined rotating speed with the speed detected by said speed detecting means and converting the difference between said speeds obtained by the comparison into a voltage value corresponding to the difference between said speeds, and outputting the voltage value; and drive control means for controlling current supplied to the motor on the basis of the voltage value from said comparator means.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-04-01 | 1994-10-01 | 1995-04-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-04-01 | 1998-10-01 | 1999-04-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-04-01 | 2002-10-01 | 2003-04-02 | $7700.00 | Window Closed / Lapsed |