Oil pressure control apparatus for automatic transmission

摘要

An oil pressure control apparatus for an automatic transmission configured with an oil pressure servo that engages and disengages a friction engagement element. The friction element is engaged by first and second hydraulic oil chambers that individually provide low torque, and can provide a higher torque when working in combination. A failure solenoid valve outputs a signal when a failure occurs to stop oil pressure to an oil pressure servo. Valves are configured to determine whether oil pressure is supplied to or discharged from the first and second hydraulic oil chambers. A switching valve is switched on the basis of the failure signal, and an oil pressure can be individually supplied to and discharged from the first and second hydraulic oil chambers based on the status of the switching solenoid valve and the signal from the failure solenoid valve.