PUMP AUTOMATIC UNLOADER Russian patent published in 2012 - IPC F04B49/35 

FIELD: engines and pumps.

SUBSTANCE: invention relates to automatic hydraulic drives, particularly, to aircraft hydraulic drives. Proposed unloader comprises case 1 with pressure, drain and discharge channels 2, 3 and 4, respectively, normally -open unloading valve 5 to communicate pressure channel 2 with discharge channel 3 via booster throttle valve 6. Control drive is composed of hydraulic cylinder 7 with piston 8 jointed to rod-gate 23 of unloading valve 5. Rod-gate end opposite piston 8 faces pressure line 2 and is arranged in rod end 9 of hydraulic cylinder 7 wherein spring 10 is arranged to act of piston 8 in direction of opening of valve 5. Pressure line 2 is communicated via throttle valve 12 with piston end 11 of cylinder 7 and with normally-open spring-loaded pilot valve 8 controlled by pressure in line 2 to communicate hydraulic cylinder chamber 11 with line 3. Piston 8 and rod-gate 23 have shared through axial channel 13 accommodating throttle valve 12 on the side of chamber 11. Pressure line 2 is connected on opposite side. Note here that line 2 is separated from cylinder chamber 9 by wall 15 provided with opening to accommodate slide valve of rod-gate 23.

EFFECT: decreased weight and overall dimensions, lower costs, higher efficiency.

5 cl, 3 dwg