Vehicle automatic transmission control apparatus with fail-safe arrangement

摘要

A control apparatus for controlling a vehicle automatic transmission including (i) a first coupling device to be engaged for establishing an emergency gear position and (ii) a second coupling device to be released for establishing the emergency gear position. The control apparatus includes: (a) first and second controller valves for controlling the respective first and second coupling devices; and (b) a fail-safe valve having (b- 1 ) a first output port connected to a drain port of the first controller valve, (b- 2 ) a first input port to which a working fluid is input, (b- 3 ) a first drain port for draining the working fluid, (b- 4 ) a second output port connected to an input port of the second controller valve, (b- 5 ) a second input port to which the working fluid is input, and (b- 6 ) a second drain port for draining the working fluid.