Hydraulic type brake apparatus

摘要

The present invention relates to a hydraulic type brake system which includes a unit for adjusting a back pressure in a turn driving hydraulic circuit mounted in a construction heavy equipment such as an excavator, etc., and in particular to a hydraulic type brake apparatus which is used together with a relief valve installed various actuator driving hydraulic circuits for adjusting a back pressure in a lower flow side of a relief valve for thereby adjusting an opening pressure of a relief valve. There is provided a back pressure adjusting unit adapted to adjust an opening pressure of the relief valve by adjusting a back pressure of the hydraulic circuit in a lower flow portion of the relief valve based on a co-operation with the actuator.