PUSHER-STEM 5S2834 - Caterpillar

Illustration 1 g00535357
Inside Front of Swing Frame (1) Swing control valve (2) Front control valveSwing control valve (1) controls the swing functions. The swing control valve (1) is located on the left inner side of the swing frame behind the front control valve. The swing control valve (1) directs the oil from the two swing piston pumps to the three swing motors.Operation of the Swing Control Valve
Neutral
Illustration 2 g00576737
Swing System in NeutralWhen the swing system is in NEUTRAL, the spool of the swing control valve is centered in the valve. The flow from the swing pumps passes through the open center section of the swing control valve. The flow then goes to the tank. The swing piston pumps are fully upstroked in NEUTRAL. Full pump flow is passing through the swing control valve. The pressure in the swing system is low and the oil between the control valve and the swing motors is blocked.
Illustration 3 g00576738
Swing Control Valve in NeutralThe swing system is in NEUTRAL. The flow from the swing pumps enters the swing control valve. The oil passes to the center area of the swing control valve spool. The spool is centered in the valve. The oil passes around the swing control valve spool. The flow then returns to the tank. The oil that is between the work ports of the spring control valve spool and the swing motors is blocked.Swinging
Illustration 4 g00576739
Swing System during SwingWhen the swing function is actuated, pilot oil acts in two places. Pilot pressurized oil from the resolver manifold pressurizes the swing dual pressure relief valve. This sets the swing dual pressure relief valve so that the acceleration pressure of 35000 kPa (5080 psi) is used to regulate the maximum pressure of the swing system. Pilot oil also enters the lower end of the swing control valve spool. This oil pushes the swing control valve spool upward. The spool movement blocks the open center passage. The movement also opens the upper passage. The flow through the upper passage opens the check valve. The oil flows through the swing control valve.After leaving the swing control valve, the oil flows to the swing crossover relief valve. The two makeup check valves, the two check valves, and the swing dual pressure relief valve are located in the swing crossover relief valve. The swing crossover relief valve is located on the left rear swing motor. Inside the swing crossover relief valve, the swing system pressure is regulated by the swing dual pressure relief valve. The oil then passes through the swing crossover relief valve to the three swing motors.
Illustration 5 g00576740
Swing Control Valve during SwingThe force of the pilot pressure has shifted the swing control valve spool to the right against the force of the centering spring. The spool movement opens a path for the oil past the left land on the swing control valve spool to the left