OPTION AR-ROADING 3534252 - Caterpillar

Illustration 1 g00780744
Parking brake (cross section) (1) Shaft (2) Passage (3) Barrel (4) Friction plate (5) Separator plate (6) Passage (7) Piston chamber (8) Spring (9) Brake piston (10) Passage (11) Brake pilot valve (12) Motor housing
Illustration 2 g00780745
Brake pilot valve (cross section) (6) Passage (10) Passage (13) Spring (14) Orifice (15) Valve (16) RetainerSeparator plates (5) are splined to motor housing (12). Friction plates (4) are splined to barrel (3) .When no pump oil is supplied to the travel motor, brake piston (9) is forced to the left by the force of spring (8). The oil in piston chamber (7) flows through passage (10) and through orifice (2) in valve (15) of brake pilot valve (11). The oil flows from orifice (2) to the case drain port of the motor. When brake piston (9) moves to the left, separator plates (5) and friction plates (4) are forced against housing (12) by the force of spring (8). The rotation of barrel (3) and the rotation of shaft (1) stop and the parking brake is engaged.Orifice (14) in valve (15) restricts oil flow from piston chamber (7). The restriction of return oil flow delays the application of the parking brake. The parking brake is delayed in order to give the machine time to stop. Earlier wear and/or damage to the machine could result if the machine stayed in motion.Prior to the operation of the travel motor, a portion of the pressure oil flows through passage (2) and through passage (6). Then, the oil flows through orifice (14) and through passage (10) into piston chamber (7). The pressure oil moves brake piston (9) to the right against the force of spring (8). The force that holds friction plates (4) and separator plates (5) to housing (12) is released and barrel (3) and shaft (1) are able to rotate.