GEAR 8E3470 - Caterpillar

Illustration 1 g01519263
(1) passage (2) chamber (3) valve (4) port (5) spring chamber (6) valve (7) spring (8) port (9) passage (10) passage (11) passageThe relief valves that are in the control valves are pilot operated relief valves. The relief valves protect the circuits from a spike in pressure. Hydraulic oil in passage (1) flows through passage (10) to spring chamber (5). When the pressure of the hydraulic oil in the spring chamber overcomes the force of spring (7), the relief valve opens. When the relief valve opens, valve (6) moves to the right. The oil in spring chamber (5) flows through port (8) into passage (9). The oil then flows through port (4) to passage (11) to the tank. At the same time, the oil pressure in chamber (2) moves valve (3) to the right. This opens port (4). Hydraulic oil in passage (1) flows past valve (3) through port (4) to passage (11). This oil then flows to the tank.