| 摘要 |
PROBLEM TO BE SOLVED: To improve comfortableness of steering feeling and stability of operation by supplying an electric current value for controlling an opening degree of a variable restriction so that a pressure oil amount which can pass the variable restriction is less than a discharge oil amount from a pump in that car- speed zone. SOLUTION: A pressure oil in the quantity corresponding to the engine revolution number is discharged from a pump 1 and flows into a flow control device 2. If the discharge oil amount of the pump 1 is more than a predetermined level, a spool valve 4 is displaced by pressure difference before and after the pressure oil passes a fixed restriction 126 and a variable restriction 124. And a part of the pressure oil is fed from a return passage 5 to the inlet of the pump 1, while the remaining flows into a through passage 121 through an insertion hole 125 and an opening 122. When the discharge oil amount is less than the predetermined level, the pressure oil flows into the through passage 121 only through the insertion hole 125. The pressure oil controlled in this way by action of the spool valve 4 is fed from an outlet 6 toward a control valve 7. Thus, the opening degree of the variable 124 controls the pressure oil supply amount to a control valve 7. |
