TUBE 2136768 - Caterpillar

Hydraulic Pumps
REAR OF TORQUE CONVERTER
1. Hydraulic pump for steering and elevator. 2. Hydraulic pump for elevator and implements.The hydraulic pumps are two-section (cartridge) vane-type pumps. The large section (cartridge) of pump (1) provides oil needed to operate the steering cylinders. The small section (cartridge) of pump (1) provides oil needed to operate the elevator motor in FAST FORWARD speed.The large section (cartridge) of pump (2) provides oil needed to operate the elevator motor in SLOW and FAST FORWARD speeds. The small section (cartridge) of pump (2) provides oil needed to operate the bowl cylinders, ejector cylinder, floor cylinder and the elevator motor in REVERSE speed.Operation of the Pump Sections
The components of all of the cartridges are similar: inlet and outlet support plates, seal packs, flex plates, cam ring (1), rotor (2), vanes (4) and inserts (9). For more information on vane-type pumps see, Special Instruction, Form No. SMHS7047.Since both pump sections (cartridges) are similar, only the description of one cartridge is given. Grooves in the flex plates send pressure oil to slots (6) in rotor (2). Oil from these slots goes into the area between inserts (9) and vanes (4). This pushes the vanes out against cam ring (1).As rotor (2) turns, the vanes in positions (E) and (F) move out and follow the shape (contour) of the cam ring. The chamber area between the vanes increases which causes a low pressure or vacuum in the chamber. This pressure difference causes oil to flow through inlet (8). The oil fills the space between vanes at positions (D) and (E) and continues to fill the space through positions (A) and (D). Oil between the vanes at positions (A) and (D) will be trapped (held) when the vane at position (D) passes the end of inlet (8). As rotor (2) continues to turn, the vanes are pushed in by the contour of cam ring (1). The chamber area between the vanes now decreases. Oil between the vanes at positions (A) and (B) is pushed into outlet (3). The oil continues to be pushed out through positions (B) and (C). When the vane at position (B) passes the end of outlet (3), the cycle is completed.Both ends of the vanes are connected by passages (7) in the rotor. The oil found in these passages keeps the pressure even on both ends of the vanes and permits the oil behind the vanes to go out (escape) as the vanes are pushed back in.
SCHEMATIC OF STEERING AND IMPLEMENT SECTIONS
1. Cam ring. 2. Rotor. 3. Outlet. 4. Vane. 5. Inlet. 6. Slot. 7. Passage. 8. Inlet. 9. Insert. 10. Outlet, A, B, C, D, E and F. Positions of vanes.Hydraulic Oil Cooler
Oil cooler (2) is fastened to the front of the radiator. The return oil to the hydraulic tank divides. Some oil goes through the oil filter and some goes to inlet (1). This oil goes through the oil cooler, through outlet (3) and back to the hydraulic tank. Air goes through the fins