Angle detecting apparatus and angle detecting method
First Claim
1. An angle detecting apparatus comprising:
- a rotor fixed to a rotating shaft, the rotor being such that a distance between two points where a straight line passing through a center of rotation of the rotor crosses an outer periphery of the rotor is constant;
a first magnetic sensor and a second magnetic sensor arranged opposite each other and close to the outer periphery of the rotor, the first magnetic sensor detecting a change in a magnetic field corresponding to a change in a first distance between the outer periphery of the rotor and the first magnetic sensor which distance varies periodically in conjunction with rotation of the rotor, thereby outputting a first detection signal, the second magnetic sensor detecting a change in a magnetic field corresponding to a change in a second distance between the outer periphery of the rotor and the second magnetic sensor which distance varies complementarily in conjunction with the variation in the first distance, thereby outputting a second detection signal;
differential operation means for performing differential operation on the first detection signal and the second detection signal; and
angle calculating means for calculating an angle of rotation of the rotating shaft based on a result of the differential operation by the differential operation means.
1 Assignment
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Accused Products
Abstract
An angle detecting apparatus includes a rotor fixed to a rotating shaft, a pair of magnetic sensors arranged opposite each other so as to output a first detection signal and a second detection signal, respectively, each of which contains information on the angle of rotation of the rotor, a differential operational circuit performing differential operation on the first detection signal and the second detection signal, and an angle calculating circuit calculating the angle of rotation of the rotating shaft based on the result of the differential operation by the differential operational circuit. Here, the distance between two points where a straight line passing through the center of rotation of the rotor crosses the outer periphery of the rotor is constant.
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Citations
12 Claims
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1. An angle detecting apparatus comprising:
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a rotor fixed to a rotating shaft, the rotor being such that a distance between two points where a straight line passing through a center of rotation of the rotor crosses an outer periphery of the rotor is constant; a first magnetic sensor and a second magnetic sensor arranged opposite each other and close to the outer periphery of the rotor, the first magnetic sensor detecting a change in a magnetic field corresponding to a change in a first distance between the outer periphery of the rotor and the first magnetic sensor which distance varies periodically in conjunction with rotation of the rotor, thereby outputting a first detection signal, the second magnetic sensor detecting a change in a magnetic field corresponding to a change in a second distance between the outer periphery of the rotor and the second magnetic sensor which distance varies complementarily in conjunction with the variation in the first distance, thereby outputting a second detection signal; differential operation means for performing differential operation on the first detection signal and the second detection signal; and angle calculating means for calculating an angle of rotation of the rotating shaft based on a result of the differential operation by the differential operation means. - View Dependent Claims (2, 3, 4)
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5. An angle detecting method of detecting an angle of rotation of a rotating shaft using a first magnetic sensor and a second magnetic sensor arranged opposite each other and close to an outer periphery of a rotor fixed to the rotating shaft, the method comprising the steps of:
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rotating the rotor together with the rotating shaft, the rotor being such that a distance between two points where a straight line passing through a center of rotation of the rotor crosses the outer periphery of the rotor is constant; allowing a first detection signal to be output by the first magnetic sensor detecting a change in a magnetic field corresponding to a change in a first distance between the outer periphery of the rotor and the first magnetic sensor which distance varies periodically in conjunction with rotation of the rotor; allowing a second detection signal to be output by the second magnetic sensor detecting a change in a magnetic field corresponding to a change in a second distance between the outer periphery of the rotor and the second magnetic sensor which distance varies complementarily in conjunction with the variation in the first distance; performing differential operation on the first detection signal and the second detection signal; and calculating the angle of rotation of the rotating shaft based on a result of the differential operation. - View Dependent Claims (6, 7, 8)
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9. An angle detecting apparatus comprising:
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a rotor fixed to a rotating shaft, the rotor being such that a distance between two points where a straight line passing through a center of rotation of the rotor crosses an outer periphery of the rotor is constant; a first magnetic sensor and a second magnetic sensor arranged at an equal distance from the center of rotation so as to have a phase difference of 90 degrees with respect to the center of rotation of the rotor, the first magnetic sensor detecting a change in a magnetic field corresponding to a change in a first distance between the outer periphery of the rotor and the first magnetic sensor which distance varies periodically in conjunction with rotation of the rotor, thereby outputting a first detection signal, the second magnetic sensor detecting a change in a magnetic field corresponding to a change in a second distance between the outer periphery of the rotor and the second magnetic sensor which distance varies periodically in conjunction with the rotation of the rotor, thereby outputting a second detection signal; a conversion table storing an angle of rotation of the rotating shaft corresponding to each of the first and second detection signals; and angle calculating means for comparing the conversion table with each of the first and second detection signals output by the first and second magnetic sensors to output the angle of rotation of the rotor. - View Dependent Claims (10)
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11. An angle detecting method of detecting an angle of rotation of a rotating shaft using a first magnetic sensor and a second magnetic sensor arranged at an equal distance from a center of rotation of a rotor fixed to the rotating shaft so as to have a phase difference of 90 degrees with respect to the center of rotation, the method comprising the steps of:
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rotating the rotor together with the rotating shaft, the rotor being such that a distance between two points where a straight line passing through the center of rotation of the rotor crosses the outer periphery of the rotor is constant; allowing a first detection signal to be output by the first magnetic sensor detecting a change in magnetic field corresponding to a change in first distance between the outer periphery of the rotor and the first magnetic sensor which distance varies periodically in conjunction with rotation of the rotor; allowing a second detection signal to be output by the second magnetic sensor detecting a change in magnetic field corresponding to a change in second distance between the outer periphery of the rotor and the second magnetic sensor which distance varies periodically in conjunction with the rotation of the rotor; and comparing a conversion table with each of the first and second detection signals output by the first and second magnetic sensors, thereby outputting the angle of rotation of the rotor, wherein the conversion table stores the angle of rotation of the rotating shaft corresponding to each of the first and second detection signals. - View Dependent Claims (12)
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Specification