STRUCTURE AND FUNCTION HYDRAULIC PUMP Actuation when acting as high pressure relief valve (Valve at piston pump delivery side) Port A is connected to the piston pump circuit and port B is connected to the charge circuit. The pressurized oil fills port C through drill hole a of piston ( 3A ). The pressurized oil at high pressure port A fills port D through groove b be- tween body and valve. Poppet ( 3A ) is in tight contact with valve seat ( 3C ).
3A 3B 3C 3D 3E B a A b C D RKS00050 If abnormal pressure is generated in the circuit and the oil pressure at ports A and D reaches to the pressure set by spring ( 3D ), poppet ( 3A ) is pushed to direction, and oil at port A is relieved to port B to reduce the oil pressure at port A . B 3A RKS00060 a A b D 3D 10-22 SK818-5 SK820-5 turbo