Schaltsteuerungseinrichtung für ein automatisches Getriebe

摘要

An automatic transmission includes a plurality of power transmitting gear trains making up a combination of forward power transmitting paths that can be selected one at a time, a plurality of frictional engaging elements for selecting one of the forward power transmitting paths at a time, and a one-way clutch for establishing a lowest-speed gear position among the forward power transmitting paths. When a gear shift is to be made from a neutral gear range to a forward gear range, one of the frictional engaging elements which is mechanically coupled to the one-way clutch is preliminarily engaged. When the gear shift can be made from the neutral gear range to the forward gear range, one of the frictional engaging elements for establishing the starting gear position starts being engaged, and thereafter those frictional engaging elements which are not necessary to establish the starting gear position are released. Because the frictional engaging element is mechanically coupled to the one-way clutch is preliminarily engaged, vibrations produced upon rotation of the one-way clutch are reliably suppressed when the gear shift is made from the neutral gear range to the forward gear range.