HOUSING-FLYWHEEL 1542595 - Caterpillar

Illustration 1 g06073054
Left Pump Stack
(1) Fan pumpFan pump (1) is located in the upper pump stack, in the engine compartment. The engine compartment cover provides access to the fan pump.Fan pump (1) supplies oil flow for the fan motor. This pump is the first in a stack of pumps that are driven by the engine through the pump drive gearbox.Fan pump (1) is an electronically controlled, axial-piston pump. The pump displacement is variable. Maximum displacement of the pump is 56 cc/rev (3.4 cu in/rev). A proportional solenoid controls the volume of oil flow through the pump.
Illustration 2 g06073378
Fan Pump Cross Section
(2) Direction control solenoid
(3) Speed control solenoid
(4) Port B
(5) Servo piston
(6) Swashplate
(7) Drive shaft
(8) Slipper pad
(9) Piston
(10) Barrel assembly
(11) Port plate
(12) Port A
(13) POR valveNote: Direction control solenoid (2) is not used for this machine application. The fan pump only generates flow to operate the fan in the forward direction.Engine rotation turns pump drive shaft (7), which then rotates the barrel assembly (10). Pistons (9) in the fan pump rotate with the barrel assembly. Piston slipper pads (8) allow the pistons to follow the angle of swashplate (6). When the swashplate is perpendicular to the drive shaft axis, no flow is generated by the pump. As the swashplate angle increases, oil flow is generated. Flow increases with the angle.Fan pump (1) receives charge oil from the charge pump through port"G1" (21). This charge oil is used to control pump oil flow and to maintain pump fill. The charge oil is directed to the following:
Forward makeup and relief valve (22)
Reverse makeup and relief valve (20)
Speed control solenoid (3) valve
Control port (16) of the pressure override relief (POR) valve (13).Each pressure circuit of the fan pump is equipped with makeup and relief valve (20) and (22). The valve function depends on direction of oil flow through the pump circuits. The makeup section allows charge oil to flow into the low-pressure circuit to replenish the oil lost to internal leakage. The relief section limits the pressure in the high-pressure circuit to 32500 1000 kPa (4713 145 psi).Since the direction control circuit is not utilized, charge oil is directed to the forward chamber of servo piston (5) only. This oil pressure moves swashplate (6) in the forward direction. In this case, high-pressure oil is directed out port"A" (12) (as shown in the above illustration).The oil pressure in the chamber on the pressurized side of servo piston (5) controls the angle of swashplate (6), and therefore, pump output. Since pump output ultimately controls fan speed, this pressure is referred to as"control pressure". The control pressure in the servo piston is approximately the same as the pressure at control port (16). If the pressure at the control port increases, the pressure in the servo piston chamber increases. In this case, pump output increases, and fan speed increases. If the pressure in the control port decreases, the pressure in the servo piston chamber decreases. In this case, pump output decreases, and fan speed decreases.The position of control