To increase productivity of bending work, while improving work environment through noise reduction and reducing a manufacturing cost of a hydraulic press brake 1.
A pump discharge flow rate of a bi-directional piston pump 31 is set to a standard pump discharge flow rate Qa when an operation state of a lifting cylinder 15 is in a high load state, and to a pump discharge flow rate Qb for a high flow rate which is greater than the standard pump discharge flow rate Qa when the operation state of the lifting cylinder 15 is in an unloaded state. A ratio Qb/Qa of the pump discharge flow rate Qb for the high flow rate to the standard pump discharge flow rate Qa is set to be smaller than a ratio Vb/Va of lifting velocity Vb of an upper table 13 when the lifting cylinder 15 is in the unloaded state to a lifting velocity Va of the upper table 13 when the lifting cylinder 15 is in the high load state.
NAKAMURA AKIRA
OKUBO TAKANORI
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Iwa Saki Kokuni
Shunichi Takahashi
Masakazu Ito
Toshio Takamatsu