HYDRAULIC PRESSURE SUPPLY DEVICE FOR INDUSTRIAL VEHICLE

摘要

A hydraulic pressure supply device for an industrial vehicle has a first hydraulic pump (1) and a second hydraulic pump (2) that are driven by an engine (E); a first hydraulic circuit (L1) for leading, as clutch control pressure, pressurized oil, which is supplied by the first hydraulic pump (1), to a transmission control device (3) after regulating the pressurized oil by a pressure regulation valve (21), leading as torque converter operation oil the pressurized oil, which has passed through the pressure regulation valve (21), to a torque converter (4), and further leading the pressurized oil, which has passed through the torque converter (4), to an oil cooler (23) ; a safety valve (22) connected to that part of the first hydraulic circuit (L1) which is between the pressure regulation valve (21) and the torque converter (4) and, if the pressure on the entrance side of the torque converter (4) is not lower than a predetermined value (P22), releasing that pressurized oil on the torque converter entrance side to a tank; a second hydraulic circuit (L2) for dividing pressurized oil from the second hydraulic pump (2) to a circuit portion that is downstream of the pressure regulation valve (21) and upstream of the safety valve (22) and to a circuit portion that is downstream of the torque converter (4) and upstream of the oil cooler (23); and a flow control section (24) for changing the proportion of the rate of flow in the second hydraulic circuit (L2) so that the proportion to a circuit part that is downstream of the torque converter (4) and upstream of the oil cooler (23) increases as the pressure at the entrance of the torque converter (4) increases.