SPRING 1S5507 - Caterpillar

Gear Pump (Steering)
Illustration 1 g03168117
Right Side of Engine Compartment (1) Pressure tap (2) Steering pump (3) Relief valveSteering pump (2) is the second in a series of two pumps which are driven by the engine flywheel. The engine drives the propel pump. The steering pump is splined to the propel pump. The engine compartment cover provides access to the steering pump.Steering pump (2) is a gear pump which produces flow when the engine is operating. The steering pump also acts as a flushing pump for the final drives. Supply flow from the steering pump is controlled by engine speed. The steering pump contains relief valve (3). The relief valve limits pressure in the steering system to 15500 700 kPa (2250 100 psi). The outlet line from the steering pump contains pressure tap (1). Hydraulic Cylinder (Steering)
Illustration 2 g03168136
Front of Machine (4) Steering cylinderHydraulic steering cylinder (4) is located behind the front wheels.The machine is equipped with single steering cylinder (4) which is located under the front of the machine. The head end of the steering cylinder is connected to the machine frame. The rod end of the steering cylinder is connected to the front bolster. The action of the steering cylinder causes the front bolster to pivot around a center pin. The front wheels are mounted to the front bolster.Steering Control Unit
Illustration 3 g03168138
Steering Column (1) Steering control unitSteering control unit (1) is located inside the steering column. The cover on the front of the steering column provides access to the steering control unit.Oil from the outlet of the steering pump flows to steering control unit (1). The steering control spool in the steering control unit is a sleeve type rotary valve which is spring centered. The metering pump is a gerotor pump. The control spool governs the direction of the turn, while the metering pump controls the rate of the turn.Steering control unit (1) contains four ports. The ports are marked for identification. The following list describes each port:
Port "P" Inlet from steering pump
Port "T" Return line to hydraulic tank
Port "R" Outlet to rod end of steering cylinder
Port "L" Outlet to head end of steering cylinder