Control apparatus for an automatic transmission

A control apparatus for an automatic transmission, comprising:

• a speed change mechanism including an input shaft for inputting a rotational drive force from a driving source, an output shaft for transmitting the rotational drive force to a plurality of wheels, and a plurality of friction engagement elements, operation states of which being switched between an engagement state and a disengagement state, so as to change a speed of a rotation inputted from the input shaft and to output the rotation with the changed speed;
• an operating member for selecting one of a plurality of shift ranges including a neutral range by being operated to one of a plurality of operation positions;
• operation position detecting means for detecting one of the operation positions to where the operating member is operated;
• a plurality of operation state switching means for switching the operation states of the plurality of friction engagement elements by regulating oil pressure of hydraulic oil which is supplied to the plurality of friction engagement elements;
• vehicle speed detecting means for detecting a vehicle speed of a vehicle;
• supply state switching means for switching operation states between a supply state in which the hydraulic oil is supplied to the plurality of operation state switching means and a cut-off state in which supply of hydraulic oil to the plurality of operation state switching means is cut off;
• and
• control means for setting one selected from among the plurality of shift ranges on the basis of the operation position detected by the operation position detecting means, the control means being adapted to form, in the case where the operating member is operated to one of the plurality of operation positions corresponding to the neutral range, a non-transmission state where the rotational drive force is prevented from being transmitted to the output shaft from the input shaft, by controlling the supply state switching means when the vehicle speed detected by the vehicle speed detecting means is smaller than a predetermined vehicle speed, whereas the control means being adapted to form the non-transmission state by controlling the plurality of operation state switching means when the vehicle speed detected by the vehicle speed detecting means is no less than the predetermined vehicle speed.