Hydraulic transmission and unloader null of engineering works

摘要

PURPOSE: To prevent the oscillation due to the deflection of the phase as the signal pressure between the load pressure and the discharge pressure of a hydraulic pump which is transmitted to an unload valve. ;CONSTITUTION: An unload valve 17 is equipped with a restrictive communicating means for allowing the first pressure receiving chamber 19 into which the discharge pressure of a hydraulic pump 9 is led and the second pressure receiving chamber 20 into which the load pressure of an actuator is led to selectively communicate, and the restrictive communicating means consists of a passage 32 whose one edge is opened to the first pressure receiving chamber 19, penetrating through a spool 18, throttle 31 formed in this passage 32, and a passage 30 which communicates to the passage 32 and can be opened to the second pressure receiving chamber 20. Accrdingly, the improvement of the operation performance and the reduction of the fatigue of an operator due to the operation can be achieved.;COPYRIGHT: (C)1993,JPO&Japio