Speed change control system for vehicles

A speed change control system, that is applied to a vehicle in which a transmission having a plurality of engagement devices whose torque capacities are changed continuously is connected to an output side of a prime mover, and in which a gear stage of the transmission is shifted among a plurality of stages by changing engagement states of the engagement devices, and that is configured to carry out a clutch-to-clutch shifting of the gear stage from a predetermined gear stage to another gear stage by gradually reducing a torque capacity of the predetermined engagement device to be disengaged while gradually increasing a torque capacity of another engagement device to be engaged, comprising:

• a torque calculator that calculates a target torque capacity of the engagement device to be engaged during a torque phase and an inertia phase under the clutch-to-clutch shifting using a common arithmetic expression, based on a target input angular acceleration of the transmission, a target output angular acceleration of the transmission, a target torque capacity of the engagement device to be disengaged, and a target output torque;
• and
• wherein the target torque capacity of the engagement device to be disengaged is changed continuously from the torque phase to the inertia phase under the clutch-to-clutch shifting.