| 摘要 |
PURPOSE:To speedily absorb in two stages the boosted pressure in a line on the pressurized-oil discharge side by connecting a main pressure valve in a bypass line to a relief valve through a pressure absorbing valve. CONSTITUTION:If the position (a1) of a direction controlling valve 20 for the state is switched to (a2), when a motor 51 is in revolution state, the poppet 35a of a pressure absorbing valve 35 is moved leftward by the high pressure in a pressurized-oil feeding and discharging line 32. While, a main pressure valve 34 in a bypass line 42 is opened by the differential pressure before and behind a spool 34c until a port (a) is closed, and the pressurized-oil in the feeding and discharging line 32 is discharged into a feeding and discharging line 31, and the increase of the pressure in the feeding and discharging line 32 is speedily absorbed. When the poppet 35a closes the port (a), and the pressure in the pressurized oil feeding and discharging line 32 increases, a relief valve 37 is opened, and the main pressure valve 34 is opened to discharge the pressurized-oil in the pressurized-oil feeding and discharging line 32 into the pressurized-oil feeding and discharging line 31. Thus, the gear contact shock for the motor 51 is speedily absorbed lightened by the absorbing function of the above-described devices.
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