COVER 5S3711 - Caterpillar

Illustration 1 g01844916
Oil makeup operation (1) Motor rotary group (2) Travel motor (3) Passage (4) Check valve (5) Swivel (6) Line (7) Line (8) Passage (9) Return passage (10) Passage (11) Travel control valveIn order to prevent cavitation in the travel motor during travel stop, makeup oil is supplied to the travel motor.During travel stop, the travel control levers or pedals are moved to the NEUTRAL position. The oil delivery from the main pumps is blocked at passage (8) of travel control valve (11) . The oil delivery from the main pumps is not supplied to the travel motors.Since no oil delivery is supplied to travel motor (1) , the travel motor will attempt to stop. However, the travel motor will continue to rotate because of the inertia (weight and size) of the machine. This causes a vacuum condition in passage (3) of the travel motor.When travel control valve (11) is in the NEUTRAL position, return oil flows from passage (9) through passage (10) . The return oil then flows through line (7) , swivel (5) , line (6) , check valve (4) and passage (3) to motor rotary group (1) as makeup oil. This makeup oil prevents cavitation in the travel motor during travel stop.Makeup oil is supplied for forward travel in the same manner as reverse travel.