| 摘要 |
PURPOSE:To prevent the heating and wear of a mechanical brake and the decrease in its braking force, by synchronizing the braking action of the mechanical brake with the stoppage of rotation of a hydraulic motor. CONSTITUTION:When a direction control valve 5 is shifted to its neutral position during the rotation of a hydraulic motor 2, the pressure of the chamber of a pilot-type direction control valve 20 is made high because of the resistance of an orifice 21 to pressurized oil flowing through it, so that the valve 20 is shifted to its left-hand position. As a result, the inlet port of a valve 14 communicates with a cylinder 16 and pressurized oil the hydraulic motor 2 acting to the valve is conducted into the cylinder so that a brake 15 remains out of operation while the hydraulic motor continues its rotation under inertial force. When the rotation of the hydraulic motor 2 has stopped, the rate of flow of the pressurized oil through the orifice 21 becomes zero and the valve 20 is shifted to its neutral positon so that the brake 15 operates. |
