| 摘要 |
PURPOSE:To reduce fatigue due to steering operation and perform safety running of a vehicle, by always suitably controlling reaction force in accordance with a running condition of the vehicle. CONSTITUTION:At low speed running, a pair of throttle ports 20, 21 of a reaction force regulating valve 15 are never extremely throttled and mutually communicated through reaction communication passages 16, 17, and pressure oil in a reaction chamber 64 of the port is fed to the other reaction chamber 63. Accordingly, the pressure oil in the chamber 64 never causes large resistance for sliding of a control valve spool 51, and steering can be performed by small operative force. At high speed running, a large pressure drop is generated between the upstream and downstream sides of an orifice 35 of a flow control valve 12, and passage sectional area in a communication part between a ring groove 25 of a throttle valve 22 and the ports 20, 21 is decreased to require larger steering force. |
