Patent ID: 8478497
Filing Date: 2013-07-02
Classification: F16H,Y10T

Abstract:
1. A hydraulic control device for a vehicle automatic transmission in which a plurality of hydraulic friction engagement devices are selectively engaged to establish a plurality of speeds having different speed ratios, comprising: a hydraulic control unit that uses an electromagnetic valve device to control engagement hydraulic pressures supplied to the respective hydraulic friction engagement devices by setting a driving current corresponding to the engagement hydraulic pressures; an estimated torque calculation unit that calculates an input torque related value of the vehicle automatic transmission; and a line hydraulic pressure setting unit that sets a line hydraulic pressure on the basis of the input torque related value, the line hydraulic pressure being a source pressure for controlling the engagement hydraulic pressures applied to the respective hydraulic friction engagement devices, wherein during a non-actual shift operation time when a predetermined speed of the vehicle automatic transmission is kept, the hydraulic control unit sets the driving current to increase, by a predetermined hydraulic pressure with respect to the line hydraulic pressure, the engagement hydraulic pressure applied to an engaged hydraulic friction engagement device of the hydraulic friction engagement device associated with formation of the predetermined speed.