TUBE AS 3487492 - Caterpillar

Schematic Of Vibration Control Valve Group
(1) Return port from vibration motors. (2) Unloading valve in over-run valve. (3) Over-run valve. (4) Outlet port to vibration motors. (5) Pilot valve in over-run valve. (6) Solenoid. (7) ON/OFF Switch. (8) Spring. (9) Vibration control valve. (10) Main relief valve. (11) Return to tank port. (12) Pilot valve in relief valve. (13) Unloading valve in relief valve. (14) Pump inlet port.Over-run Valve
This valve is a pilot-operated type. It limits the motor return line pressure to 8000 kPa (1150 psi) during the stopping process of the vibrators.To turn OFF the vibration, switch (7) is moved to OFF. Solenoid (6) is de-energized and spring (8) returns the valve spool to the rest position. Return port (1) is blocked to the flow of oil. The over-run of the eccentric mass of the vibrator causes a sudden pressure increase in the return line. Over-run valve (3) opens and allows the vibrator to slow down gradually. The oil goes from the return line, through the over-run valve, to the motor supply line to prevent cavitation of the motor.Oil from the vibration motor return line enters the valve group through port (1). The pressure of the oil acts against both sides of unloading valve (2) and the top of pilot valve (5). When the pressure becomes more than the pilot valve setting, the valve moves and allows a small amount of oil to flow. With oil flowing past the orifice, a pressure drop is created at the spring side of the unloading valve. System pressure on the top of the unloading valve causes the valve to move. This allows full system flow to vibration motor supply port (4).The pressure setting of the valve can be changed with an adjustment screw.Main Relief Valve
The maximum working pressure of the circuit is limited to 15 000 kPa (2200 psi) by the main relief valve. This valve is a direct-acting type. Oil from the vibration pump enters the valve group through passage (14). The pressure of the oil acts against both sides of unloading valve (13) and the top of pilot valve (12). When the pressure becomes more than the pilot valve setting, the valve moves and allows a small amount of oil to flow. With oil flowing past the orifice, a pressure drop is created at the spring side of the unloading valve. System pressure on the top of the unloading valve causes the valve to move. This allows oil flow to tank return port (11).The pressure setting of the valve can be changed with an adjustment screw.Vibration Circuit Flows
Vibration System Schematic
(1) Case drain line. (2) Rear drum vibration motor. (3) Front drum vibration motor. (4) Case drain line. (5) Over-run valve. (6) Solenoid valve spool. (7) ON-OFF switch. (8) Hydraulic oil cooler. (9) Main relief valve. (10) Filter. (11) Hydraulic tank. (12) Vibration pump. (13) Diesel engine.Oil flows from vibration pump (12) to solenoid valve spool (6). When vibration ON-OFF switch (7) on the propulsion control lever is moved