| 摘要 |
PURPOSE:To decrease the fluid motor stopping shock when an operation valve is reversibly operated and decrease the peak pressure. CONSTITUTION:A fluid motor 1 and an operation valve 2 are communicated with each other by first and second main circuits 3, 4, and check valves 5 and brake valves 6 are provided, and these circuits are communicated with each other by a short circuit 8 provided with a safety valve 7. The safety valve 7 is formed so that set pressure is raised by fluid pressure to be supplied into a spring chamber 7a, and the spring chamber 7a is connected to the brake valves 6 by a passage 9, moreover a slowly return valve 29 is provided. The operation valve 2 is so formed as to be switched to a neutral position N, a first position A for supplying the discharge fluid of a fluid pump 12 to the first main circuit 3, and a second position B for supplying the discharge fluid to the second main circuit 4, while the brake valve 6 is formed so as to be respectively pointioned in a shut-off position F when the operation valve 2 is in the neutral position N, positioned in a first position G when the valve 2 is in a first position A, and positioned in a second position H when the valve 2 is in a second position B, so that the set pressure of the safety valve 7 is gradually raised. |
