GRILL 7X9136 - Caterpillar

Illustration 1 g00274368
Top View of Steering Component Locations
(1) Hydraulic and steering pump
(2) Combination valve
(3) Steering accumulator
(4) Steering metering pump
(AA) Outlet port to the combination valve
(BB) Inlet port from the combination valve
(CC) Outlet port to the right steering cylinder
(DD) Load sensing signal port
(EE) Outlet port to the left steering cylinder
Illustration 2 g00274369
Right Side View of Steering Component Locations
(1) Hydraulic and steering pump
(2) Combination valve
(4) Steering metering pump
(5) Steering cylinder crossover relief valve
(6) Right steering cylinder
(AA) Outlet port to the combination valve
(BB) Inlet port from the combination valve
(CC) Outlet port to the right steering cylinder
(DD) Load sensing signal port
(EE) Outlet port to the left steering cylinder The steering circuit is composed of three main components:
Steering priority valve
Steering metering pump (4).
Left and right steering cylinders.Hydraulic oil for the steering circuit is supplied by the hydraulic and steering pump (1). The steering priority valve gives priority to the steering function over the available hydraulic pump flow. The priority valve senses pressure in the steering circuit. Then, the priority valve directs flow to steering accumulator (3) until the demand is satisfied.Typically, the requirements of the oil flow for the steering circuit are significantly less than the available hydraulic pump flow. This means that oil flow to other implement circuits will not be interrupted when the steering is operated. Steering metering pump (4) provides oil flow to the steering cylinders. This depends on the direction and the rotation of the steering wheel. The steering cylinders that are mounted on the front axle turn the front wheels to the right or to the left.Oil Flow of the Steering Hydraulic System
Illustration 3 g00274371
Steering System in the HOLD Position
(1) Hydraulic and steering pump and pressure and flow compensator valve
(2) Combination valve
(3) Steering accumulator
(4) Steering metering pump
(5) Steering cylinder crossover relief valve
(6) Steering cylinders
(7) Gerotor
(8) Rotary sleeve
(9) Signal resolver
(10) Steering priority valve
(11) Hydraulic tank
(BB) First pressure reduction oil
(CC) Second pressure reduction oil
(FF) Reduced pilot oil
(JJ) Trapped oil
(LL) Tank oil Second pressure reduction oil (CC) is approximately 2275 kPa (330 psi) when the steering wheel is not turned. Oil (CC) will be approximately 2100 kPa (305 psi) above the load pressure of the steering cylinder. This difference is called margin pressure. Oil flows through the check valve for the steering circuit, to steering accumulator (3) and/or to steering metering pump (4). Oil flows to steering metering pump (4) through the inlet port. Then, the oil flows through the check valve and to rotary sleeve (8). Steering accumulator (3) matches the pressure of the steering demand above 6900 kPa (1000 psi).The pilot reduced oil (FF) from steering priority valve (10) then flows to the signal port on steering metering pump (4). Signal oil then flows through an orifice in rotary sleeve (8) back to hydraulic tank (11).When there is no steering demand, the oil pressure in the signal line is approximately 345 kPa (50 psi). Oil in the signal line is supplied from the center passage in the steering priority valve (10). The oil then flows into the spring chamber of the steering