Electric power steering apparatus
First Claim
1. An electric power steering apparatus comprising:
- a first device for detection of steering torque of a steering line;
a motor for exerting assist steering torque on the steering line;
a motor drive unit for driving the motor;
a second device for determining a target current to be supplied to the motor based upon at least a signal of steering torque delivered by the first device;
a third device for detection of a motor current running through the motor; and
a control unit for generating a signal for motor drive based upon at least a deviation between the target current and motor current and transmitting the signal for motor drive to the motor drive unit, wherein the control unit comprises a fourth device for weakening a magnetic field within the motor according to one of the deviation and a value computed based upon the deviation.
1 Assignment
0 Petitions
Accused Products
Abstract
An electric power steering apparatus is provided, which has a first device for detection of steering torque, a motor, a motor drive unit, a second device for determining a target current based upon at least a signal of steering torque, a third device for detection of a motor current, and a control unit for generating a signal for motor drive based upon at least a deviation between the target current and motor current and transmitting the signal for motor drive to the motor drive unit. The apparatus has a feature that the control unit includes a fourth device for weakening a magnetic field within the motor according to the deviation or a value computed based upon the deviation.
32 Citations
3 Claims
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1. An electric power steering apparatus comprising:
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a first device for detection of steering torque of a steering line;
a motor for exerting assist steering torque on the steering line;
a motor drive unit for driving the motor;
a second device for determining a target current to be supplied to the motor based upon at least a signal of steering torque delivered by the first device;
a third device for detection of a motor current running through the motor; and
a control unit for generating a signal for motor drive based upon at least a deviation between the target current and motor current and transmitting the signal for motor drive to the motor drive unit, wherein the control unit comprises a fourth device for weakening a magnetic field within the motor according to one of the deviation and a value computed based upon the deviation.
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2. An electric power steering apparatus comprising:
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a first device for detection of steering torque of a steering line;
a motor for exerting assist steering torque on the steering line;
a motor drive unit for driving the motor;
a second device for determining a target current to be supplied to the motor based upon at least a signal of steering torque delivered by the first device;
a third device for detection of a motor current running through the motor; and
a control unit for generating a signal for motor drive based upon at least a deviation between the target current and motor current and transmitting the signal for motor drive to the motor drive unit, wherein the control unit comprises a fourth device for weakening a magnetic field within the motor according to the motor current.
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3. An electric power steering apparatus comprising:
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a first device for detection of steering torque of a steering line;
a motor for exerting assist steering torque on the steering line;
a motor drive unit for driving the motor;
a second device for determining a target current to be supplied to the motor based upon at least a signal of steering torque delivered by the first device;
a third device for detection of a motor current running through the motor;
a fourth device for detection of a rotational velocity of the motor; and
a control unit for generating a signal for motor drive based upon at least a deviation between the target current and motor current and transmitting the signal for motor drive to the motor drive unit, wherein the control unit comprises a fifth device for weakening a magnetic field within the motor according to the rotational velocity of the motor.
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Specification