HYDRAULIC PRESSURE CONTROL DEVICE FOR AUTOMATIC TRANSMISSION

PROBLEM TO BE SOLVED: To provide a hydraulic pressure control device for an automatic transmission capable of suppressing overshoot which occurs when line pressure of hydraulic fluid is raised to operate the automatic transmission at the time of starting an engine at a low temperature. SOLUTION: In the hydraulic pressure control device for the automatic transmission of this invention equipped with an oil pump driven by the engine, a line pressure control valve for generating the line pressure of the transmission mechanism and a line pressure control means for instructing an instruction pressure of the line pressure and raising the line pressure, the oil pump is provided apart from a main shaft and the main shaft and a rotation shaft of the oil pump is connected with a chain and the oil pump is driven by rotation of the main shaft by the engine. The line pressure to be raised at the time of starting the engine at a low temperature with small discharging quantity of hydraulic fluid from the oil pump is limited to be smaller than a maximum value of predetermined line pressure instruction pressure and the discharge quantity of the hydraulic fluid from the oil pump is suppressed by limiting engine speed. COPYRIGHT: (C)2006,JPO&NCIPI