Transmission shift control apparatus arranged to perform compulsory shift-down action of continiously variable transmission

摘要

A shift control apparatus for controlling a continuously variable transmission device (18) including a continuously variable transmission mechanism (42, 46, 48) having rotary elements (42, 46) and operable to transmit a rotary motion of a drive power source (12) of an automotive vehicle to a drive wheel (24) of the automotive vehicle, such that a speed ratio of said mechanism is continuously variable, the shift control apparatus includes a power-transmission-state determining device (94) for determining whether the mechanism is placed in a non-power-transmitting state, a speed-ratio determining device (90) for determining whether the mechanism is placed in a lowest-speed position, a rotation-stop detecting device (92) for determining whether the rotary elements are at rest, and a compulsory-speed-ratio-change implementing device (96) for effecting a compulsory shift-down action of the mechanism toward the lowest-speed position when the mechanism is placed in the non-power-transmitting state while the mechanism is not placed in the lowest-speed position and while the rotary elements of the mechanism are at rest.