HOUSING-SCREEN 3859284 - Caterpillar

Illustration 1 g00905126
Hydraulic Schematic of Manifold and Relief Valve (1) Manifold and relief valve (2) Hydraulic filter (bypass) (3) Inlet port to the manifold and relief valve (4) Supply lines to rotor tilt cylinders (5) Shift valve (logic) (6) Supply line to rotor transmission (7) Gear pump (8) Relief valve (9) Relief to differential lock (10) Orifice (11) "Port D" to rotor transmission
Illustration 2 g00883294
Manifold and Relief Valve (Priority Valve)Manifold and relief valve (1) is an integral part of the hydraulic circuit in the propel and rotor transmission system. Hydraulic oil flows into the priority valve at inlet "Port P" (3) from hydraulic filter (2) and the transmission pump. Supply lines (4) will operate the rotor tilt cylinder and the shutdown lock valve.The flow rate for the relief valve is 11.35 L/min (3 US gpm) to scavenge pump (7) and the propel transmission.As a flow of 11.35 L/min (3 US gpm) goes to the propel transmission, the pressure drop across orifice (10) is sufficient enough to cause shift valve (5) (logic) to shift. This will allow flow to the rotor transmission control through "Port D" (11) .If scavenge pump (7) locks up, relief valve (8) will open. As a result, the flow will go to the transmission cooler and the lube circuit for the flywheel gear through port "T2". This valve will open when the pressure reaches 8963 kPa (1300 psi). Consequently, the rotor transmission will not engage in this condition because shift valve (5) (logic) has shifted as a result of no pressure drop across orifice (10) .The remaining oil will flow through shift valve (5) and to the rotor transmission control.The hood tilt function and the differential lock are secondary functions for the manifold and relief valve.