FRAME ASSEM. 4K2030 - Caterpillar

When the machine is turned to the right, the steering control valve operates in a similar manner.When you turn the steering wheel clockwise in order to make a right turn, pilot oil enters pilot port (11). The oil fills cavity (28). The pressure of the oil in cavity (28) causes directional spool (13) to move left. As spool (13) moves to the left, washer (24) will also move to the left. This causes spring (18) to compress. Any oil that was in chamber (25) flows back to the hydraulic oil tank.When directional spool (13) moves left, pressure oil flows from pump inlet passage (21) and flows through slots in spool (13). The oil then flows into steering cylinder passage (22) and out of steering cylinder port (27) .The pressure oil then flows out of the port for steering cylinder for right turns (3). The pressure oil then flows to the head end of the steering cylinder on the left side of the machine. The pressure oil also flows to the rod end of the steering cylinder on the right side of the machine.At the same time, the return oil flows from the head end of the steering cylinder on the right side of the machine. The return oil also flows from the rod end of the steering cylinder on the left side of the machine. This process causes the machine to articulate to the right. The return oil flows back to the hydraulic oil tank.Crossover Relief Valve for the Steering Cylinders
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Crossover Relief Valve for the Steering CylindersThe crossover relief valve for the steering cylinders is located on the front right side of the steering control valve.
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Schematic for the Steering Control ValveCrossover Relief Valve for the Steering Cylinders
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Crossover Relief Valve for the Steering Cylinders (1) Screw. (2) Jam nut. (3) Spring. (4) Spring chamber. (5) Sleeve. (6) Holes. (7) Valve face. (8) Passage. (9) Poppet for the relief valve. (10) Drain hole. (11) Face of sleeve. (12) Passage. (13) Valve face. (14) Valve seat.The crossover relief valve for the steering cylinders relieves shock loading in the steering system. The crossover relief valve operates when the steering system is in neutral or when the steering system is articulating the machine.Steering cylinder pressure is sensed in passages (8) and (12) of the steering control valve. Steering cylinder pressure is also sensed on valve faces (7) and (13) .When the steering cylinders are moved by external steering forces, the pressure in passages (8) and (12) can increase suddenly.A pressure increase in passage (8) acts on valve face (7). If the pressure is greater than the valve setting, poppet (9) moves left. This causes spring (3) to compress. The pressure is relieved to passage (12) through holes (6) .If the pressure in passage (12) is greater than the pressure setting of the crossover relief valve, the pressure acts on valve face (13). The pressure also acts on the face of sleeve (11) .Sleeve (5) and poppet (9) move to the