KIT-SEAL 5253500 - Caterpillar

Illustration 1 g00759210
Hydraulic Pump (4) Charge pump (15) Drive shaft (16) Swashplate (17) Adjustment screw (servo piston) (18) Barrel assembly (19) Charge pump inlet (20) Piston (21) Spring (22) Valve plate (23) Main circuit portsThe hydraulic pump for the water spray system is a variable displacement piston pump. The pump output is electrically controlled through the electrical displacement control (EDC). The EDC maintains the position of the swashplate in proportion to the electrical input.When the engine is running, shaft (15), barrel assembly (18) and charge pump (4) are rotating. There are nine pistons (20) in barrel assembly (18). Spring (21) keeps a force on barrel assembly (18) in order to make a high pressure seal between barrel assembly (18) and valve plate (22). When barrel assembly (18) is rotating, each piston (20) follows the angle of swashplate (16). If the angle of swashplate (16) is at zero, the pistons do not move in and out of barrel assembly (18). This would cause no flow of oil. Charge oil from charge pump (4) will maintain oil pressure in the hydraulic pump in order to keep barrel assembly (18) full of oil. Charge oil lubricates the pump components. This makes up for the normal, internal loss of oil, which is due to leakage. The position of swashplate (16) is controlled by the EDC and servo piston (17). The EDC receives an electrical signal from the flow control box. This causes movement of the servo valve inside the EDC. Servo piston (17) will activate and servo piston (17) will adjust due to charge oil that is routed from the servo valve. Servo piston (17) controls the direction and the amount of angle for swashplate (16) .Oil flows from the pump to the drive motor and back to the pump. This oil flows through main circuit ports (23). The position of swashplate (16) determines the direction of flow.EDC
Illustration 2 g00759265
(9) Displacement control spool (10) Pressure control pilot (PCP) (11) Sensing pistons (12) Feedback linkage (13) Servo control piston (14) Electronic displacement control (EDC) (17) Neutral adjustment (servo piston) (24) Spring (25) neutral adjustment (EDC) (26) Control oil passagesElectric displacement control (14) is mounted on the hydraulic pump.The pump control consists of EDC (14), displacement control spool (9), and servo control piston (13). EDC (14) is a two-stage electrohydraulic control. The EDC uses feedback linkage (12) and control oil (26) from the charge pump in order to set up a closed swashplate control circuit. EDC (14) receives an electrical input from the flow analyzer control dial at the pressure control pilot valve (10) .EDC (14) uses an electrohydraulic pressure control pilot in order to control differential pilot pressure. PCP (10) converts an electrical input signal to a hydraulic input signal in order to operate spring (24) that is centered in the sensing piston (11). Sensing piston (11) is mechanically hooked up with the displacement control spool (9) through feedback linkage (12). As sensing piston (11) moves, the displacement control spool is moved. This opens a