CONTROL AS 7R3399 - Caterpillar

Illustration 1 g00873499
The swing system is independent of the implement system and the travel system. The machine has two bent axis type motors and two swing drives. The swing motors and the swing drives are located on the rear 90 degree segment of the swing gear.The swing control valve directs pump flow from the swing piston pump to both swing motors at the same time. Each swing motor powers a swing drive. The swing drives are planetary reduction drives. A spring engaged swing parking brake is located inside each swing drive. The swing parking brakes are released with low pressure pilot oil that is controlled by the swing pressure switch, the machine control module and the swing parking brake solenoid valve. The swing system uses an open center swing control valve. The swing control valve includes the directional control spool and a swing dual pressure relief valve. The swing dual pressure relief