| 摘要 |
PURPOSE:To start a fluid actuator smoothly by switching a control valve under the condition of communication of a high pressure side with a low pressure side to throttle moreover the communication of the high pressure side with the low pressure side for gently raising the pressure on the high pressure side. CONSTITUTION:When a variable throttle 24 is throttled, oil pressure in a high pressure flow path 14 and a connection flow path 26 is raised and at the same time pilot pressure is also raised, so that oil flows via a pilot flow path 30 toward a pilot operation switching valve 22. Oil flow from the pilot flow path 30 is throttled by a variable throttle valve 32 and gently supplied to the pilot operation switching valve 22. With the raise of the pilot pressure, the pilot operation switching valve 22 is gently switched from a normal position 22a via a transitional position 22c to an operational position 22b. The amount of oil flowing to a low pressure flow path 14 is thus gradually decreased to gradually increase the pressure in a high pressure flow path 10, so that the oil pressure of a hydraulic motor 1 is gradually raised to start revolution smoothly. |
