Patent attributes
A hydraulic control apparatus of an automatic transmission. The hydraulic control apparatus of the automatic transmission has a hydraulic servo for controlling an engaging state of a clutch C-1 on the basis of supplied oil pressure, a linear solenoid valve for C-1 for outputting signal pressure by adjusting the oil pressure, a control valve for outputting control pressure provided by adjusting line pressure PL on the basis of the signal pressure of the linear solenoid valve for C-1, and a C-1 apply relay valve for inputting, selectively switching and outputting the control pressure and the line pressure PL to the hydraulic servo. An orifice for regulating the flow rate of the oil is arranged in an oil path g for inputting the line pressure PL to this C-1 apply relay valve.