TURBOCHARGER AS 4795799 - Caterpillar

Illustration 1 g02968018
Left Side of Drum (1) Brake supply line (2) Minimum displacement limiter (3) Drum motor (4) Flushing valve (5) Drum speed sensor (6) Shift valve line (7) Flushing relief valveDrum motor (3) is located 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.The parking brake is spring applied and hydraulically released. Brake supply line (1) 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 propel pump, through the forward, and reverse circuit lines.When the machine is in the high speed range, the shift solenoid is energized. In this case, charge oil enters the propel motor through shift valve line (6). In the high speed range, the propel motor operates at the minimum angle.The drum motor contains flushing valve (4). The flushing valve spool directs oil from the low-pressure side of the drum propel loop to flushing relief valve (7). When the pressure in the low-pressure side of the propel loop is greater than 1600 kPa (232 psi), the flushing relief valve opens. When the flushing relief valve is open, an orifice diverts oil from the low-pressure side of the drum propel loop into the drum motor case drain.The drum motor case drain line (not shown) directs oil from the drum motor case to the return manifold.Drum motor (3) is equipped with maximum displacement limiter (not shown) and minimum displacement limiter (2). When the shift solenoid is not energized, the drum motor operates at maximum displacement in the working speed range. When the shift solenoid is energized, charge oil is directed into shift valve line (6). In this case, the motor operates at minimum displacement in the travel speed range. Drum motor (3) is equipped with speed sensor (5). The machine ECM uses input from this sensor and input from the axle speed sensor in order to calculate the actual machine speed. The machine ECM uses this input in the control logic for uncommanded movement and for propel system calibration.Note: The propel system is controlled using open loop logic. The machine does not use input from drum speed sensor (5) in order to control the speed of the machine.
Illustration 2 g02968036
Motor Cross Section (2) Minimum displacement limiter (7) Flushing relief valve (8) Barrel assembly (9) Piston (10) Control spool (11) Shift port (12) Check valve (13) Output shaft (14) Control plate (15) Maximum displacement limiter (16) Actuator piston (17) Rod (18) Flushing block (19) Flushing spoolThe drum motor has a bent axis. The speed of this type of motor shifts when the bend angle of the motor is changed. The motor is operated against either minimum displacement limiter (2) or maximum displacement limiter (15). The displacement limiters can be adjusted to control the minimum and maximum motor speeds.A pressure differential between the forward port and the reverse