Patent ID: 9707994
Date: 2017-07-18
CPC Classifications: B62D

Claim:
1. A power steering apparatus comprising: a steering mechanism formed of an iron-series metallic material and which steers steerable wheels in accordance with a steering operation of a steering wheel; an electrically driven motor which provides a steering force for the steering mechanism; a speed reduction mechanism formed of the iron-series metallic material, interposed between the steering mechanism and the electrically driven motor, and which transmits a revolution force of the electrically driven motor to the steering mechanism; a torque sensor which detects a steering torque generated in the steering mechanism; a control unit which calculates a motor command current drivingly controlling the electrically driven motor on a basis of the steering torque and outputs the motor command current to the electrically driven motor; a steering load average value calculating circuit installed in the control unit and which calculates an average value of a steering load corresponding value, the steering load corresponding value corresponding to any one of the steering torque within a predetermined interval of time, the motor command current, and a motor actual current actually flowing through the electrically driven motor; and an abnormality detection circuit installed in the control unit, which compares the average value of the steering load corresponding value with a specified value stored in the control unit, and detects an abnormality of the apparatus when the average value is larger than the specified value, wherein the steering load average value calculating circuit stores a newest value of the average value of the steering load corresponding value into a non-volatile memory, when an ignition switch of a vehicle is turned off, wherein the steering load average value calculating circuit calculates the average value of the steering load corresponding value on a basis of an information of the average value of the steering load corresponding value stored in the non-volatile memory and the steering load corresponding value after the ignition switch is turned on, when the ignition switch of the vehicle is turned on, and wherein the steering load average value calculating circuit calculates the average value of the steering load corresponding value by making a weight of the average value of the steering load corresponding value stored in the non-volatile memory larger than the steering load corresponding value after the ignition switch is turned on.