PUMP ASSEM. 7N5445 - Caterpillar

Illustration 1 g01173015
Travel motor (1) Inlet port B (supply oil or return oil) (2) Inlet port A (supply oil or return oil) (3) Displacement change valve (4) Shuttle valve (5) Shaft (6) Piston (7) Rod (8) Plate (9) Spring (11) Piston assembly (12) Barrel assembly (13) Housing (14) Passage (Barrel) (15) Passage (Valve plate) (16) Head (17) Plate (18) Separator plate (19) Brake spring (21) Swashplate (22) Guide (24) Retainer plate (25) Valve plate (26) Brake piston (27) Drain port (28) Passage (supply oil or return oil) (29) Pressure reducing valve (31) Pilot port (automatic speed change)The travel motor can be divided into the following three groups:
The rotary group consists of the following components: barrel assembly (12), shaft (5), piston assembly (11), spring (9) and guide (22) .
The parking brake consists of the following components: brake piston (26), plate (17), separator plate (18), spring (19) and pressure reducing valve (29) .
The displacement change valve consists of the following components: piston (6), rod (7), shuttle valve (4) and displacement change valve (3) .The flow of the pump oil depends on the direction of travel. Pump oil flows into the travel motor through port (1) or port (2). Pump oil is forced out of the travel motor through port (2) or (1) .The case drain oil returns to the hydraulic tank through drain port (27) of housing (13) .Supply oil flows into the left travel motor through port (2) during forward travel. The oil from port (2) flows through the passage in head (16) and through passage (15) in valve plate (25). See Illustration 2. The oil then flows through passage (14) of barrel assembly (12), and the oil forces piston assembly (11) to move.
Illustration 2 g00580938
Motor passages (side view from head) (A) Bottom center (B) Inlet side (high pressure) (C) Top center (D) Outlet side (low pressure) (14) Passage (barrel) (15) Passage (valve plate) (30) Passage (valve plate)The piston assembly (11) slides on the surface of plate (8) from the top center to the bottom center. The piston rotates with barrel assembly (12). Oil is drawn through passage (15) of valve plate (25) into piston assemblies (11). Oil is discharged through passage (14) of piston assemblies (11). The oil then flows through passage (30) of valve plate (25). The oil continues to flow through port (1), and the barrel turns counterclockwise.Shaft (5) is splined to barrel (12). The shaft and barrel of the left travel motor rotate counterclockwise for forward travel.In reverse travel, port (2) functions as an oil return port. Port (1) functions as a supply port. The left travel motor rotates clockwise.When the right travel motor is supplied pump oil through port (1), the right travel motor turns clockwise for forward travel. Pump oil through port (2) turns the motor counterclockwise for reverse travel.