| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an assist device capable of restricting fluctuation of steering force small when returning a steering wheel 1. <P>SOLUTION: The assist device is provided with a hydraulic pump 7 capable of separately supplying the hydraulic pressure to two cylinder chambers 6b and 6c with a piston. The assist device is also provided with a bypass passage 13 for communicating the two cylinder chambers 6b and 6c with each other, a fail safe valve for opening/closing the bypass passage 13, a controller 10 for controlling opening/closing of the fail safe valve, and a bypass valve 15 for reducing the pressure by communicating the low-pressure side cylinder chamber 6b or 6c with a pressure reduction port with operation of a spool by a pressure difference between the two cylinder chambers 6b and 6c. When returning the steering wheel 1, the controller 10 transfers the fail safe valve from the open state to the closed state after opening the fail safe valve synchronously with a start of the operation of the spool of the bypass valve 15. <P>COPYRIGHT: (C)2007,JPO&INPIT |
