| 摘要 |
PURPOSE: To decrease control flow at nonsteering and reduce energy loss by retaining the control flow to the min. flow if a power cylinder has low load pressure, and increasing the control flow to the flow required for assistant force when the load pressure arrives at the predetermined pressure. CONSTITUTION: A flow control mechanism 2 controls flow in accordance with the load pressure P of a power cylinder. Namely, if the power cylinder C has the low load pressure P, control flow Q is retained to the min. flow Q1 ; when the load pressure P arrives at the predetermined pressure P2 , the control flow Q is increased to flow Q2 required for assistance. Therefore, in the low load pressure P range, namely, at nonsteering, only the min. flow Q1 passes through a valve mechanism 7. Decreasing flow passing through the valve mechanism 7 depresses pressure loss generated in cylinder variable throttles 7a-7d, a pipe line, etc., accordingly to reduce energy loss. The higher load pressure P at steering results in increase to the flow Q2 to obtain sufficient assistant force. |
