SEAL, LIP EXTERNAL 7098403C1 - Caterpillar

Illustration 1 g00930602
The main components of the hydrostatic drive system are power train pump (13) and dual piston motor (17). The pump and the motor are connected to each other at the pressure side and the return side. This is a closed loop circuit.Power train pump (13) is a variable displacement piston pump. Dual piston motor (17) is a variable displacement axial piston motor.The swashplate angle of pump (13) determines the displacement of the pump. The swashplate angle also determines the direction of rotation for dual piston motor (17). The direction of travel for the machine is also determined by the swashplate.The IQAN Monitoring and Control System controls the hydrostatic drive system. The IQAN uses electrical input from the following components in order to control the hydrostatic drive system: speed sensors, accelerator pedals, temperature sensors and pressure sensors. The IQAN also uses electrical input from the direction selector switch, the seat direction switch, the door switch, and the accelerator pedal in order to control the hydrostatic drive system.The parameters of the IQAN software optimize the operation of the hydrostatic drive system. The IQAN reads all the input signals from the sensors. The IQAN then compares the input signal to the set of parameters in the IQAN software. Then, the IQAN generates output signals. The output signals regulate the components of hydrostatic drive system.When the temperature of the drive loop is out-of-range, the IQAN retards the electrical signals to solenoids (5) and (6) .When the operator depresses the accelerator pedal an electrical signal is sent to the IQAN. The IQAN processes the electrical signals from the accelerator pedal, the direction selector switch, and the seat direction switch. Then, the IQAN sends an electrical signal to proportional solenoids (5) or (6). The IQAN sends an electrical signal to proportional solenoid (18) also. An electrical signal to proportional solenoid (6) causes the machine to move in the reverse direction. An electrical signal to proportional solenoid (5) causes the machine to move forward.Reference: For more information about the IQAN, refer to Systems Operation, RENR6127, "IQAN Monitoring and Control System".The power train pump will begin to upstroke when the electrical signal that is sent to the proportional solenoids reaches the minimum current. This causes the swashplate to tilt. As a result, oil flows from power train pump (13) to the dual piston motor (17) .Power train pump (13) produces the minimum displacement when the electrical signal to the proportional solenoids is at the minimum current. Power train pump (13) produces the maximum displacement when the electrical signal to the proportional solenoids is at the maximum current.The oil from the power train pump causes the power train motor to rotate. The rotation of the power train motor depends on the swashplate angle in the power train pump.