PUMP GP-GEAR 0R7822 - Caterpillar

Illustration 1 g00854678
Charge relief valve (1) Supply passage for charge oil from the charge pump (2) Spring chamber (3) Passage (4) Port (5) Spring (6) Spring retainer (7) Poppet (8) Passage to case drain (9) Seating surface of poppetCharge oil flows from the hydraulic oil filter through passage (1) to passage (3). The oil flows from passage (3) through port (4) to poppet (7). When the pressure against surface (9) of poppet (7) overcomes the force of spring (5), poppet (7) moves to the left and the poppet pushes spring retainer (6) against the force of spring (5). Oil flows past poppet (7) into spring chamber (2). Then, the oil flows from spring chamber (2) through passage (8) to the case drain of the piston pump.Poppet (7) oscillates as the flow of charge oil fluctuates in order to maintain a constant pressure for the charge oil.