JPS6426055A - Shift controller for automatic transmission - Google Patents

Abstract

PURPOSE:To perform shift control so smoothly without disengaging a clutch by attaching each transfer torque variable device to both maximum and minimum speed steps, shifting it in increasing the extent of load torque by degrees and, after shifting, releasing this load torque. CONSTITUTION:Each of solenoid multiple disk clutch C1 and C2 being driven by a solenoid multiple disk clutch actuator 15 is attached to both maximum and minimum speed steps of a transmission 6. And, at the time of ship-up and shift-down, an electronic controller 9 applies the specified fluid pressure to the multiple disk clutch C1 or C2 via the actuator 15, while torque transfer is temporarily loaded on a gear train of the maximum or minimum speed step from the existing speed step and, after mesh neutral of the existing speed step, load is increased, engine speed is regulated and gears of a synchromesh is unmeshed, then gearing into the next shift takes place. Afterward, current to the actuator 15 is released, and the load of the maximum or minimum speed step by these clutches C1 and C2 is released. Thus, shift operation is smoothly performable without disengaging the clutch.