Showa Corporation

Yoshitaka Kubo

Akira Fujisaki

Harunori Imagawa

Shunya Senda

Yoshinori Takeuchi

In a motor-driven power steering apparatus, there is provided a correction coefficient memory previously storing an output correction coefficient to be multiplied by a current control signal applied to an electric motor at certain points in a range of temperatures in such a manner as to correct a temperature dependent output torque changing in dependence upon an environmental temperature of the electric motor to a demand output torque required in the electric motor. A temperature sensor for detecting the environmental temperature of the electric motor is provided, a correction coefficient computing circuit for reading the output correction coefficient corresponding to the temperature detected by the temperature sensor from the correction coefficient memory is provided, and a current control computing means for calculating a corrected current control signal by multiplying the current control signal of the electric motor computed on the basis of a steered condition of a vehicle by the output correction coefficient read from the correction coefficient computing circuit is provided. The drive control signal is output based on the corrected current control signal to the motor driving means.

Motor-driven power steering apparatus

In a motor-driven power steering apparatus, the main coil winding and auxiliary coil winding are wound around the same slot of a stator core in a parallel manner, a motor drive means has a main driver feeding at least to the main coil windings, and an auxiliary driver feeding only to the auxiliary coil windings, the main driver being actuated so as to be capable of assisting the steering during normal conditions of a control system of an electric motor, and the auxiliary driver is actuated so as to execute an auxiliary assist corresponding to a motor friction torque under abnormal conditions of the control system of the electric motor.

In a motor-driven power steering apparatus, a plurality of rotational position detecting sensors are provided in an electric motor, and during an abnormality in any one rotational sensor, the electric motor can be driven by using a detected result of any other one rotational position detecting sensor.

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Tochigi, Japan

Yoshitaka Kubo