Torque sensor
First Claim
1. A torque sensor, comprising:
- a magnetic metal film with magnetic anisotropy attached to a torque transmission shaft;
an exciting coil and a detector coil each installed near the magnetic metal film;
an excitation power supply source that generates an ac excitation signal to be supplied to the exciting coil;
a reference voltage generator that is connected to the excitation power supply source to input the excitation signal and send the ac excitation signal whose reference voltage indicating a midpoint of the ac excitation signal is set to a voltage corresponding to a 50% duty ratio of the ac excitation signal, to the exciting coil; and
a torque detector that is connected to the detector coil and detects a torque applied to the torque transmission shaft based on an output of the detector coil when the torque is applied.
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Accused Products
Abstract
In a torque sensor having a magnetic metal film with magnetic anisotropy attached to a torque transmission shaft and an exciting coil and a detector coil each installed near the magnetic metal film, there is provided a reference voltage generator that supplies an ac excitation signal whose reference voltage indicating a midpoint of the ac excitation signal is set to a voltage corresponding to a 50% duty ratio of the ac excitation signal, to the exciting coil, such that a torque applied to the torque transmission shaft is detected based on an output of the detector coil, thereby achieving improved torque detection accuracy by enabling generation of an excitation signal of large amplitude that is free of upper-lower imbalance relative to the reference voltage as the midpoint and accurate detection of the magnitude and accuracy of detection waveform amplitude. In addition, the excitation signal is generated based on clock frequency of a microcomputer that detects the applied torque, thereby achieving improved torque detection accuracy by enabling generation of an excitation signal of large amplitude that is free of upper-lower imbalance relative to the reference voltage as the midpoint and accurate detection of the magnitude and accuracy of detection waveform amplitude.
20 Citations
16 Claims
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1. A torque sensor, comprising:
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a magnetic metal film with magnetic anisotropy attached to a torque transmission shaft;
an exciting coil and a detector coil each installed near the magnetic metal film;
an excitation power supply source that generates an ac excitation signal to be supplied to the exciting coil;
a reference voltage generator that is connected to the excitation power supply source to input the excitation signal and send the ac excitation signal whose reference voltage indicating a midpoint of the ac excitation signal is set to a voltage corresponding to a 50% duty ratio of the ac excitation signal, to the exciting coil; and
a torque detector that is connected to the detector coil and detects a torque applied to the torque transmission shaft based on an output of the detector coil when the torque is applied. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A torque sensor, comprising:
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a magnetic metal film with magnetic anisotropy attached to a torque transmission shaft;
an exciting coil and a detector coil each installed near the magnetic metal film;
an excitation power supply source that supplies a power for an excitation signal to be supplied to the exciting coil;
a microcomputer that constitutes the torque detector; and
an excitation signal generator that is connected to the excitation power supply source to input the power and generates the excitation signal from the power based on clock frequency of the microcomputer. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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Specification