STRUCTURE, FUNCTION, & MAINTENANCE STANDARD SWING MOTOR 12 Operation of swing lock 1. When swing lock solenoid valve is deactivated When the swing lock solenoid valve is deactivated, the pressurized oil from the main pump is shut off and port B is connected to the tank circuit. As a result, brake piston (7) is pushed down by brake spring (1), discs (5) and plates (6) are pushed together, and the brake is applied. 2. When swing lock solenoid valve is excited When the swing lock solenoid valve is excited, the valve is switched and the pressure oil from the main pump enters port B and flows to brake chamber a .
The pressure oil entering chamber a overcomes brake spring (1) and pushes brake piston (7) up. As a result, discs (5) and plates (6) are separated and the brake is released. PC210/240-7K 10-95