MOTOR GP-TRAVEL 1886396 - Caterpillar

Illustration 1 g06121892
Left Side of Drum
(1) Drum speed sensor
(2) Case drain line
(3) Reverse port"B"
(4) Maximum displacement limiter
(5) Forward port"A"
(6) Shift port
(7) Flushing spool
(8) Flushing relief valve
(9) Drum motorDrum motor (9) is on the left side of the drum. This motor is a piston motor with two speeds. The drum motor drives the drum through a planetary gear reducer. The planetary gear reducer contains an integral parking brake.Note: The axle motor and the drum motor are similar. Refer to Piston Motor (Axle Propulsion) for additional information about this type of motor.The parking brake is spring applied and hydraulically released. The brake inlet line (not shown) on the motor provides charge oil to release the parking brake.The drum motor receives supply oil from and returns low-pressure oil to the drum rotating group of the propulsion pump. This hydraulic oil flows through forward port"A" (5) and reverse port"B" (3).The drum motor contains a flushing valve. Flushing valve spool (7) directs oil from the low-pressure side of the drum propulsion loop to flushing relief valve (8). When the pressure in the low-pressure side of the propulsion loop is greater than the setting of the valve, the flushing relief valve opens. When the flushing relief valve is open, an orifice diverts oil from the low-pressure side of the drum propulsion loop into the drum motor case drain.Case drain line (2) for drum motor (9) directs oil from the drum motor case to the return manifold.Drum motor (9) is equipped with maximum displacement limiter (4) and a minimum displacement limiter (not visible). When the shift solenoid is not energized, the drum motor operates at maximum displacement. When the shift solenoid is energized, charge oil is directed into shift port (6). In this case, the motor operates at maximum displacement.Drum motor (9) is equipped with speed sensor (1). The machine ECM uses input from this sensor and input from the axle speed sensor to calculate the actual machine speed. The machine ECM uses this input in the control logic for uncommanded movement.Note: Sensor input is used for propulsion system calibration. The propulsion system is controlled using open-loop logic. The machine's propel calibration procedure uses the motor speed sensors to synchronize the axle and drum. From this calibration, ECM output to the pump control is determined for propulsion speed control, based on propulsion lever position and automatic speed control setting.Note: The speed sensor screw threads are not blind tapped. These threads tap into the case cavity. The speed sensor retaining screws require the use of 1E2200B (Loctite 242 Blue) sealant thread lock. This sealant prevents motor case oil from weeping past the threads.