HARNESS AS-ALARM 4418287 - Caterpillar

Piston Pump
Illustration 1 g00891299
(1) Actuator piston
(2) Feedback lever
(3) Proportional solenoid
(4) Passage
(5) Solenoid valve
(6) Pressure override valve (POR Valve)
(7) Reel out port
(8) Input shaft
(9) Swashplate
(10) Piston
(11) Barrel
(12) Spring
(13) Port plate
(14) Reel in port
(15) Charge pump The pump for the winch hydrostatic system is a variable displacement piston pump. The winch pump is mounted to the back of the second hystat pump. The input shaft of the winch pump engages a coupling from the second hystat pump in order to drive the winch pump.When the engine is running, shaft (8) and barrel (11) are rotating. There are nine pistons (10) in the barrel. Port plate (13) and swashplate (9) are stationary within the pump housing. Port plate (13) and swashplate (9) do not rotate. Spring (12) maintains a force against barrel (11) and port plate (13). When barrel (11) is rotating, each piston (10) follows the angle of swashplate (9).If the angle of swashplate (9) is zero, pistons (10) do not move in and out of barrel (11) and there is no oil flow. Charge oil from charge pump (15) maintains oil pressure in the pump in order to perform the following tasks:
Keep barrel (11) full of oil.
Lubricate the pump components.
Provide makeup oil for internal leakage.
Provide oil to solenoid valve (5) in order to shift actuator piston (1) and change the angle of swashplate (9).The position of swashplate (9) is determined by actuator piston (1). The winch control lever that is located on the right console sends a pulse width modulated signal to the ECM. The ECM determines the operator request from the signal. The ECM sends a pulse width modulated signal to proportional solenoid valve (3). The signal is proportional to the operator input. Proportional solenoid valve (3) directs oil through passage (4) to the corresponding end of actuator piston (1).As actuator piston (1) begins to move, the angle of swashplate (9) begins to increase. As pistons (10) follow swashplate (9), the pistons begin to move in and out of barrel (11). As piston (10) moves out of barrel (11), oil is drawn from the reel out port (7) of the winch through port plate (13). As piston (10) follows swashplate (9) and the pistons move into barrel (11), the oil is pushed through port plate (13) into the reel in port (14) of the loop.As the angle of swashplate (9) increases, the output flow of the pump also increases.Charge Pump
Illustration 2 g01348948
Charge pump
(16) Orifice
(17) Passage
(18) Crossover relief valve
(19) Oil filter
(20) Filter bypass valve
(21) Passage
(22) Ring gear
(23) Pinion gear
(24) Supply passage for the charge pump from the hydraulic tank
(25) Passage
(26) Charge relief valve
(27) Supply passage for the charge pump
(28) Crossover relief valve The charge pump is a gerotor pump that is located on the rear of the winch pump. The charge pump provides oil for the winch hydrostatic system when you start the machine. Charge oil is also used as makeup oil for the drive loop. Charge oil is also used for lubrication of pump components and of motor components and