Power steering apparatus

An electric power steering apparatus for calculating a steering assist command value based on a steering torque and a velocity, generating a PWM signal based on said steering assist command value, PWM-controlling a motor via a motor drive circuit comprised of switching elements, and assist-controlling a steering system that an electromagnetic type motor relay is inserted between said motor drive circuit and said motor, comprising:

• a steering status detecting section that detects a steering status of a steering wheel, outputs a longtime steering holding signal when detecting that said steering status is a longtime steering holding status, and outputs a normal steering signal when detecting that said steering status is a normal steering status, and
• a motor current control section that determines a motor current control value for controlling a motor current flowing in said electromagnetic type motor relay in accordance with said longtime steering holding signal or said normal steering signal that is outputted from said steering status detecting section,
• wherein said steering status detecting section detects a steering status at a time that a given time elapses from a time of determining that said steering status is a steering holding status as said longtime steering holding status.

An electric power steering apparatus for calculating a steering assist command value based on a steering torque and a velocity, generating a PWM signal based on said steering assist command value, PWM-controlling a three-phase brushless DC motor via a motor drive circuit comprised of switching elements, and assist-controlling a steering system that an electromagnetic type motor relay is inserted between said motor drive circuit and said three-phase brushless DC motor, comprising:

• a temperature estimating section that estimates a temperature of a relay spring portion or a relay coil portion of said electromagnetic type motor relay,
• a comparing section that compares an estimated temperature value that is estimated by said temperature estimating section with a given temperature, and
• a motor current control section that controls a motor current flowing in said electromagnetic type motor relay in accordance with a comparison result of said comparing section.