Pressure reducing valve

A pressure reducing valve includes main and pilot valves. The pilot valve is configured to regulate a pilot pressure, and includes pilot, drain, and first control-oil ports, a first opening cross section between the first control-oil and pilot ports, a second opening cross section between the pilot and drain ports; and a pilot part. The pilot part is configured to keep the pilot pressure at least substantially constant and control the first and second opening cross sections to be open during a pressure control operation. The main valve is fluidically connected to the pilot port and includes a second control-oil port, an outlet port, a third opening cross section between the second control-oil port and the outlet port, and a control part configured to control the third opening cross section based on the pilot pressure.