| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the load of an engine E by placing first and second main pumps MP1, MP2 into the unloaded state when starting the engine E. <P>SOLUTION: When an ignition key is operated to start the engine E, a controller C opens a solenoid on-off valve 33 and supplies a pilot passage 32 with a discharge fluid from a sub-pump SP. When a pressure fluid flows through the pilot passage 32, the pressure of the pilot passage 32 at that time is applied to a pilot chamber 37b of an unloading valve 37 to switch the unloading valve 37 into an open position. When the unloading valve 37 is opened, the first and second main pumps MP1, MP2 are unloaded through the unloading valve 37. The engine E is thus started in the unloaded state of the first and second main pumps MP1, MP2. <P>COPYRIGHT: (C)2010,JPO&INPIT |
