| 摘要 |
PURPOSE:To obtain appropreate reactional force matched with a running condition by introducing pump port pressure into a reaction chamber through an orifice while, on the other hand, providing a relief valve in a passage that connects said reaction chamber to a tank port side and opening said valve by means of the tank port pressure. CONSTITUTION:An annular groove 43, which is connected to a pump port 45, is connected to a reaction chamber 37 through an orifice 50 formed in a spool 25. Also, the reaction chamber 37 is connected to an annular chamber 56, which is connected to a tank port, through passages 51, 52 formed in the spool 25 and a housing 7. A relief valve 53 is provided midway in the passage 52, and a pilot cylinder part 60 which controls the opening and closing of the valve 53 is formed in the housing 7. A chamber 63 which actuates the pressure in the direction in which the relief valve 53 is opened, is connected to the pump port 45 through a passage 64 and the annular groove 43, and the other chamber 65 is connected to the tank port side. Therefore, the pressure to start opening the valve 53 becomes great when the steering load is small when driving at a high speed, etc., providing high steering reactional force, and vice versa when driving at a low speed. |
