| 摘要 |
PROBLEM TO BE SOLVED: To provide a brake device for working machine as improvement of a conventional one involving such a problem that eventual stop of a pressure source for generation of an incremental operating pressure during application of brakes causes drop of the braking pressure to lead to a drop of the braking force. SOLUTION: If a hydraulic pump 11 stops during braking to cause a stop of supplying a pressure oil to the master cylinder 8, the oil pressure p1 between the pump 11 and a check valve 16 drops, and the pressure oil in an oil chamber 8b is willing to counterflow to the pump 11 via a pressure reducing valve 12. However, this counterflow is checked by the check valve 16, so that the amount of pressure oil between the master cylinder 8 and check valve 16 does not change, and the oil pressure between the pressure reducing valve 12 and check valve 16 is kept unchanged at p1. Accordingly the assist pressure pa generated in the oil pressure 8b is maintained, and it is possible to generate a high braking pressure pc with the same stamping force as before the pump 11 is stopped. |
