Patent ID: 8229629

Claim:
A vehicle steering control system for controlling operation of an electric vehicle steering device which applies a steering assist force to a steering mechanism via a gear mechanism, comprising: a temperature estimating section for estimating a gear temperature as a temperature of the gear mechanism or around the gear mechanism; and a correcting section for correcting the steering assist force according to the estimated gear temperature, wherein the temperature estimating section estimates the gear temperature based on convective heat from a radiator or based on self-heating of an electric motor that applies the steering assist force or based on radiant heat from the internal combustion engine or based on ambient temperature, wherein the correcting section corrects the steering assist force by adding a low-temperature correcting assist force determined according to the gear temperature to a normal assist force, which is applied when the gear temperature is above a prescribed temperature, and wherein the prescribed value of the gear temperature is a temperature at which the preload of the gear mechanism begins to increase.