| 摘要 |
PURPOSE:To carry out the braking operation in correspondence with the load variation by providing a braking circuit provided with a pressure control valve in a main circuit between a direction changeover valve and the actuator and supplying a pressure fluid to a pilot chamber of the pressure control valve in linkage with the direction changeover. CONSTITUTION:When the direction changeover valve 4 is switched to a position 4b, a changeover valve 12 is set to a position 12b, and a pump discharge pressure acts on the pilot chamber 34a of the pressure control valve 7a of the braking circuit 9a via a check valve 10 and a pilot circuit 6a. The pilot chamber 34b of the pressure control valve 7b of other braking circuit 9b is communicated with a tank T. Accordingly, a motor 2 is driven. When the changeover valve 4 is switched to a neutral position during the motor being driven, the changeover valve 12 also assumes a neutral position and main circuits 3a and 3b are closed. But the motor 2 continues to rotate under load inertia, thereby holding the main valve 32b of the control valve 7b at a righthand position, increasing the fluid pressure within the main circuit 3b, and lowering the pressure within the main circuit 3a. |
