TUBE 1737150 - Caterpillar

Illustration 1 g00774031
(1) Piston pump group (2) Pilot port (one per rotating group) (3) Maximum angle stop screw (one per rotating group) (4) Shaft (5) Pilot port (one per rotating group) (6) Cross over relief valves and makeup valves (two per rotating group) (7) Charge pressure relief valve (8) Adjustment for the pump null (one per rotating group)
Illustration 2 g00772209
(4) Shaft (9) Piston (10) Control arm for the swashplate (11) Actuator (12) Slider (13) Swashplate (14) Retraction plate (15) Rotating group 1 (16) Rotating group 2 (A) Passage to port (B) Passage to portThe pump group consists of the following components: two rotating groups (15) and (16), two actuators (11), two swashplates (13), shaft (4), four cross over relief valves (6), charge pressure relief valve (7) and speed sensing valve.The pilot ports (2) and (5) are used to control the angle of the swashplate (13). The angle of the swashplate and the engine rpm controls the output of the pump. The pilot ports are connected to the resolver network on the pilot valve.The piston pump operates in a closed loop system. The standard piston pump is a variable displacement piston pump with a maximum displacement of 45 cc/rev (2.75 in3/rev). The piston pump for machines that are equipped with two speed has a maximum displacement of 38.4 0.6 cc/rev (2.34 0.04 cu in/rev). The pump is driven from the engine flywheel by a coupling that is splined to the pump input shaft.
Illustration 3 g00774128
(17) Spring collar (18) Actuator piston (19) Spring collar (20) SpringThe shaft (4) for the rotating groups consists of two shafts that are splined together between the two rotating groups. Each swashplate within the rotating group can operate independently. Rotating group 1 (15) supplies the left hand piston motor and rotating group 2 (16) supplies the right hand piston motor. For the following example of the operation of the pump, rotating group 1 will be used. Rotating group 2 will operate in the same manner.When the operator moves the pilot valve in order to move the machine forward, pilot oil flows out of the pilot valve and into pilot port (5). This causes the actuator piston (18) to