STEERING WHEEL AS 3W5957 - Caterpillar

Illustration 2 g02404316
Cross Section of Joystick (9) Port for bucket (open) (RH Joystick) (10) Port for boom lower (RH Joystick) (11) Port for bucket close (RH Joystick) (12) Port for boom (raise) (RH Joystick) (13) Port for swing left (LH Joystick) (14) Port for stick out (LH Joystick) (15) Port for swing right (LH Joystick) (16) Port for stick in (LH Joystick) (17) Hydraulic control unit (18) Plunger (19) Return spring (20) Control spring (21) Passage (22) Line to tank (23) Pilot pressure supply line from pilot manifold (24) Line to main control valve (25) PlateEach pilot control valve has four valves that control two operations. The left pilot control valve has two valves for the stick and two valves for the swing. The right pilot control valve has two valves for the boom and two valves for the bucket.When the joystick is moved to the right, plate (25) tilts to the left. Plate (25) pushes down on plunger (18). The seat pushes control spring (20) and return spring (19). The force of the control spring (20) moves control spool (17) downward and passage (21) is opened. The oil can go through the passages and out of port (24) through the line to the main control valve. The oil pressure that is generated at the pilot control valve moves the main control valve spools. This permits oil flow to the implements.The oil at the opposite end of the main control valve stem flows through the port return passage and to the return chamber. The oil then flows through port (22) to the hydraulic tank.Return spring (19) in the pilot control valve provides the necessary force in order to allow joysticks to return to the NEUTRAL position when released.When the joystick is actuated, control springs (20) are compressed. This causes control spool (17) to move downward. Control spool (17) controls the pilot oil pressure to the main control valve. The pilot pressure that is delivered to the main control valve is proportional to the travel distance of the joystick.
Illustration 3 g02404836
Typical joystick schematic showing ports 1 through 4.
Illustration 4 g02404657
Joystick pressure curves (Ports 1 and 3) (A) Pressure (bar) (A1) 24 2.5 (A2) 11.5 1.2 (A3) 6 0.4 (B) Operating angle (Degrees) (B1) 2 degrees 30' 1degree 10' (B2) 11 degrees 50' 2 degrees (B3) 22 degrees 1degree 35' (B4) 23 degrees 15' 1 degree
Illustration 5 g02404700
Joystick pressure curves (Ports 2 and 4) (C) Pressure (bar) (C1) 6 0.4 (C2) 11.5 1.2 (C3) 24 0.6 (D) Operating angle (Degrees) (D1) 2 degrees 30' 1 degrees 10' (D2) 11 degrees 20' 2 degrees (D3) 18 degrees 20' 1 degreesThe pilot pressure that is delivered to the main control valve is proportional to the travel distance of the joystick. Refer to Illustration 4 and Illustration 5. The amount of change in the flow rate from the main control valve to the implements and/or motors is proportional. The proportion is based off the