Torque sensor and motor-driven power steering apparatus using thereof
First Claim
1. A torque sensor including magnetic media attached to input and output axes coupled through a torsion bar, respectively, and each having magnetic tracks magnetized at a predetermined pitch and magnetic detection elements disposed opposite to each of said magnetic media and sensitive to said magnetic tracks, whereby torque is detected on the basis of output signals of said magnetic detection elements, comprising:
- at least two magnetic tracks formed in each of said magnetic media attached to said input and output axes with a magnetic phase difference in order to detect torque.
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Accused Products
Abstract
A torque sensor includes input and output axes coupled through a torsion bar, magnetic media attached to the input and output axes and having magnetic tracks magnetized at a predetermined pitch and magnetic detection elements disposed opposite to the magnetic media to be sensitive to the magnetic tracks. At least two magnetic tracks for detection of torque are formed with a magnetic phase difference in each of the magnetic media attached to the input and output axes.
18 Citations
27 Claims
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1. A torque sensor including magnetic media attached to input and output axes coupled through a torsion bar, respectively, and each having magnetic tracks magnetized at a predetermined pitch and magnetic detection elements disposed opposite to each of said magnetic media and sensitive to said magnetic tracks, whereby torque is detected on the basis of output signals of said magnetic detection elements, comprising:
at least two magnetic tracks formed in each of said magnetic media attached to said input and output axes with a magnetic phase difference in order to detect torque. - View Dependent Claims (3, 5, 7, 9, 11, 13, 15, 17)
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2. A torque sensor including first and second axes coupled through a torsion bar, a first magnetic medium rotated together with said first axis and having magnetic tracks magnetized at a predetermined pitch, a second magnetic medium rotated together with said second axis and having magnetic tracks magnetized at a predetermined pitch, first magnetic detection elements disposed to be sensitive to said magnetic tracks of said first magnetic medium, and second magnetic detection elements disposed to be sensitive to said magnetic tracks of said second magnetic medium, whereby torque is detected on the basis of output signals of said first and second magnetic detection elements, comprising:
at least two magnetic tracks formed in each of said first and second magnetic media at equal magnetization pitch and with a magnetic phase difference. - View Dependent Claims (4, 6, 8, 10, 12, 14, 16, 18)
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19. A torque sensor including magnetic media attached to input and output axes coupled through a torsion bar, respectively, and each having magnetic tracks magnetized at a predetermined pitch and magnetic detection elements disposed opposite to each of said magnetic media and sensitive to said magnetic tracks, whereby torque is detected on the basis of output signals of said magnetic detection elements, comprising:
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at least two magnetic tracks disposed in each of said magnetic media and having a magnetic phase difference;
magnetic tracks disposed in each of said magnetic media to be able to identify the number of at least four or more periods of a magnetization pattern in said at least two magnetic tracks; and
an operation unit for calculating torque exerted on said input and output axes from detection signals of said magnetic tracks having said magnetic phase difference and detection signal of said magnetic tracks disposed to be able to identify the number of at least four or more periods.
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20. A torque sensor comprising a rotational axis of which a rotational angle is detected by electromagnetic induction operation and a distortion sensor disposed in said rotational axis to detect torque exerted on said rotational axis and be driven by utilizing electric power produced by said electromagnetic induction operation.
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21. A torque sensor for detecting torque exerted between first and second axes coupled through a torsion bar on the basis of a torsional angle produced in said torsion bar, comprising:
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at least one or more moving coils rotated together with said first or second axis and disposed to produce electromagnetic induction by a magnetic field perpendicular to said first or second axis; and
at least one or more fixed coils fixedly mounted relatively to said first or second axis and disposed to produce electromagnetic induction by a magnetic field perpendicular to said first or second axis. - View Dependent Claims (22, 23, 24, 25)
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26. A motor-driven power steering apparatus which transmits rotation of a steering wheel to wheels through a rotational axis and detects at least torque of said rotational axis so that a motor for assisting operation of the steering wheel is controlled on the basis of the detected signal, wherein
said detection of said torque is performed by providing a plurality of magnetic tracks each having a phase difference in a plurality of magnetic drums provided in two rotational axes coupled through a torsion bar and by means of a contactless magnetic encoder system.
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27. A motor-driven power steering apparatus which transmits rotation of a steering wheel to wheels through a rotational axis and detects at least torque of said rotational axis so that a motor for assisting operation of the steering wheel is controlled on the basis of the detected signal, wherein
said detection of said torque is performed by detecting distortion of said rotational axis and taking out the detected signal by means of electromagnetic induction from a moving coil provided in said rotational axis to at least two fixed coils disposed around said rotational axis.
Specification