ELECTRIC POWER STEERING DEVICE
First Claim
1. An electric power steering device comprising:
- a motor for steering assist that is supplied with a current in accordance with a steering torque applied to a steering member;
a temperature detection portion that detects temperature of a specific site whose temperature increases due to driving of the motor;
a control portion that controls the current to be equal to or less than a restriction value that is changed according to the temperature of the specific site, if the temperature detected by the temperature detection portion exceeds a threshold temperature;
a temperature value storage portion that stores the temperature of the specific site when an engine is stopped;
a restriction value storage portion that stores the restriction value provided when the engine is stopped, as a pre-stop restriction value;
a computation portion that computes a temperature difference between the temperature of the specific site detected when a starter switch for starting the engine is turned on and the temperature stored when the engine is stopped; and
a setting portion that sets the restriction value to be equal to or greater than the pre-stop restriction value according to the temperature difference computed by the computation portion, over a predetermined time following a time of turning-on of the starter switch, if the temperature of the specific site at the time of the turning-on of the starter switch is above the threshold temperature.
1 Assignment
0 Petitions
Accused Products
Abstract
In an electric power steering device, if the temperature of a specific site that increases due to the driving of a steering assist motor exceeds a threshold, the motor current is controlled to be equal to or below a current restriction value. The temperature Toff of the specific site detected when an engine is stopped, and the current restriction value Ioff provided when the engine is stopped are stored into a storage. A temperature difference Ta between the temperature detected when a starter switch is turned on and the temperature Toff is computed. If the temperature of the specific site when the starter switch is turned on is above the threshold, the current restriction value is set to be equal to or above the current restriction value Ioff stored in the storage, according to the temperature difference Ta, over a time following the turning-on of the starter switch.
30 Citations
9 Claims
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1. An electric power steering device comprising:
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a motor for steering assist that is supplied with a current in accordance with a steering torque applied to a steering member; a temperature detection portion that detects temperature of a specific site whose temperature increases due to driving of the motor; a control portion that controls the current to be equal to or less than a restriction value that is changed according to the temperature of the specific site, if the temperature detected by the temperature detection portion exceeds a threshold temperature; a temperature value storage portion that stores the temperature of the specific site when an engine is stopped; a restriction value storage portion that stores the restriction value provided when the engine is stopped, as a pre-stop restriction value; a computation portion that computes a temperature difference between the temperature of the specific site detected when a starter switch for starting the engine is turned on and the temperature stored when the engine is stopped; and a setting portion that sets the restriction value to be equal to or greater than the pre-stop restriction value according to the temperature difference computed by the computation portion, over a predetermined time following a time of turning-on of the starter switch, if the temperature of the specific site at the time of the turning-on of the starter switch is above the threshold temperature. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An electric power steering device comprising:
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a motor for steering assist that is supplied with a current in accordance with a steering torque applied to a steering member; a temperature detection portion that detects temperature of a specific site whose temperature increases due to driving of the motor; a control portion that controls the current to be equal to or less than a restriction value that is changed according to the temperature of the specific site, if the temperature detected by the temperature detection portion exceeds a threshold temperature; a storage portion that stores the restriction value provided when an engine is stopped, as a pre-stop restriction value; a determination portion that determines a temperature correction value that corrects the temperature of the specific site detected, based on the pre-stop restriction value, when the starter switch for starting the engine is turned on; and a temperature value setting portion that sets a temperature value obtained by adding the temperature correction value to the temperature of the specific site detected at a time of turning-on of the starter switch, as the temperature of the specific site, over a predetermined time following the turning-on of the starter switch. - View Dependent Claims (8, 9)
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Specification