| 摘要 |
<p>PURPOSE:To structure an unload valve and a relief valve which is provided on a pilot oil supplying passage with compactness. CONSTITUTION:A pilot operating control valve for supplying and discharging operation oil is provided on a hydraulic actuator which drives a back hoe device, while a pilot valve is provided for outputting result selected by operation of a lever which selects the hydraulic actuator to be operated as a pilot pressure. An unload valve 57 and a pilot pressure adjusting relief valve 58 are provided on an oil supplying passage to the pilot valve, while a relief valve 58 is arranged inside a spool 60 of the unload valve 57.</p> |
