| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a transmission ratio variable steering system for a vehicle whereby a phase current of a brushless electric motor can accurately be detected, a temperature at a predetermined portion can precisely be estimated, and controllability of the motor can be improved. <P>SOLUTION: This transmission ratio variable steering system 100 for the vehicle is provided with an input shaft 20 connected to a steering wheel 10 side so that a steering angle is inputted, an output shaft 40 connected to a steered wheel FW side and outputting a steered angle, a transmission ratio variable device 30 intervening between the input shaft and the output shaft and capable of varying the transmission ratio of the steered angle with respect to the steering angle by the driving motor 31 as a driving source, and a control device 60 for controlling the electric current to the driving motor in order to vary the transmission ratio in accordance with the traveling state of the vehicle. The driving motor is the brushless electric motor, and the control device is equipped with phase current detecting means 64 and 65 for detecting the phase current of the brushless electric motor, and a temperature estimating means for estimating the temperature at the predetermined portion based on the detected phase current. Thus, it is possible to achieve the transmission ratio variable steering system for the vehicle whereby the temperature can be estimated accurately. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
