CAP 1415978 - Caterpillar

Illustration 1 g06294072
Oil makeup operation
(1) Motor rotary group
(2) Left travel motor
(3) Passage
(4) Check valve
(5) Line
(6) Swivel
(7) Line
(8) Return passage
(9) Passage
(10) Left travel control valve
(11) PassageReturn oil flow from the travel control valve is used as makeup oil. Makeup oil prevents a vacuum condition in the travel motor when operation is stopped. The description for makeup operation is given for left travel. The makeup operation for left travel functions in the same manner as the makeup operation for right travel.When left travel control valve (10) is returned to the NEUTRAL position to stop left travel, pump oil supply to left travel motor (2) is blocked at passage (11). The motor continues to rotate because of the mass (weight and size) of the machine. Oil pressure decreases at passage (3) of motor rotary group (1). Check valve (4) opens.When left travel control valve (10) is in the NEUTRAL position, return oil from return passage (8) flows to passage (9). The return oil then flows through line (7), and through swivel (6). The return oil then enters left travel motor (2). The oil passes through check valve (4) and passage (3). The oil then enters motor rotary group (1) as makeup oil. The makeup oil circuit eliminates the possibility of cavitation in the travel motor.