4) 4) BRAKE SYSTEM BRAKE SYSTEM (1) (1) Control valve swing brake system Control valve swing brake system This is the brake system to stop the swing motion of the excavator during operation. In this system, the hydraulic circuit is throttled by the swing control valve, and the resistance created by this throttling works as a brake force to slow down the swing motion.
Work Deceleration Stop A B A B A B MCV MCV MCV MCV A, B opened MCV A, B throttled MCV A, B closed (2) (2) Mechanical swing parking brake system Mechanical swing parking brake system The mechanical swing parking brake system is installed to prevent the upper structure from swinging downhill because of its own weight when the excavator is parked on a slope since it completely eliminates the hydraulic drift of swing motion while the excavator is on a slop, work can be done more easily and safely. ① Brake assembly Brake assembly Circumferential rotation of separate plate (27) is constrained by the groove located at casing (1).
When housing is pressed down by brake spring (30) through friction plate (26), separate plate (27) and brake piston (28), friction force occurs there. Cylinder (3) is constrained by this friction force and brake acts, while brake releases when hydraulic force exceeds spring force. 30 28 27 26 3 1 1 Casing 3 Cylinder 26 Friction plate 27 Separate plate 28 Brake piston 30 Brake spring 2-18