The Kobelco excavator rotary parking brake is a wet multi-disc brake. The brake is released only when the brake release pressure oil S enters the brake cylinder 6 (normally closed brake). When performing swing operations and stick retracting operations (that is, when the solenoid valve 9 is not energized), the brake release pressure oil S comes from the pilot pump 10 when performing other operations other than swing and stick retracting operations, or when the engine When stopping, the brake release pressure oil S is connected to the hydraulic oil tank, and the parking brake is automatically realized by the spring 1.
When the brake is in the ON position (that is, during operations other than turning and/or stick retracting operations), the signal from the turning pressure switch 7 and/or the stick retracting pressure switch 8 is not transmitted to the pump valve controller (PVC), so that the solenoid valve 9 remains energized (ON). When the solenoid valve 9 is energized, the brake release pressure s is released to the fuel tank port, so that the force of the spring 1 passes downward through the piston 2, so that the steel plate 3 engages with the circumferential part of the cylinder 6, and the friction plate 4 is connected to the motor housing. The inner surface is engaged. The friction force is equal to the thrust load, and the steel plate 3 and the cylinder block 6 are braked by the friction force.
When the brake is in the OFF position (i.e. during the turning operation and/or the stick retracting operation), the signals from the automatic turning pressure switch 7 and (or) the stick retracting pressure switch 8 are transmitted to the pump valve controller (PVC ) To de-energize the solenoid valve 9. Then, the brake release pressure SI pushes upwards, against the spring 1, so that the piston leaves the steel plate 3 and the friction plate 4, thereby releasing the brake.
