Patent ID: 7600463

Claim:
An oil pressure supply circuit which supplies pressurized oil to an oil pressure power steering device and a cargo handling device of an industrial vehicle, comprising: an oil pump which discharges pressurized oil; a power steering oil passage which supplies pressurized oil to the power steering device; a load signal port which outputs a load pressure exerted on the power steering device, the load signal port being released to an oil tank when the power steering device is not operative; a signal pressure passage which connects the load signal port and the power steering oil passage, the signal pressure passage comprising a first orifice and a second orifice which are disposed in series such that the first orifice is disposed nearer to the load signal port than the second orifice; a priority flow rate control valve which preferentially distributes the pressurized oil discharged by the oil pump to the power steering oil passage, and distributes excess oil to the cargo handling device, the priority flow rate control valve being configured to increase a distribution ratio of the pressurized oil to the power steering oil passage as a differential pressure between the power steering oil passage and the signal pressure passage between the first orifice and the second orifice decreases; a bypass passage which bypasses one of the first orifice and the second orifice; and a bypass valve which opens and closes the bypass passage.