Hill hold equipped creeping prevention device of automatic gearbox

摘要

To carry out the creep prevention release and the hill hold release in the accelerator OFF time, in the mode to reduction the shock and in an adequate timing. SOLUTION: Until the accelerator OFF time t1, the pressure PC of a forward clutch is reduced to make into the slip condition so as to prevent the creeping and a band brake is made in a fastening condition by increasing the pressure PB so as to carry out the hill hold. After the instant t1, the pressure Pc is raised at an inclination a to refasten the forward clutch and so as to release the creep prevention. While the pressure PC is made in the maximum value at the refastening completing time t2 when the rotation frequency N1 of a turbine is made 0, the pressure PB is reduced suddenly to a fastening capacity limit pressure PBS, and after that and the pressure is reduced gradually to release the band brake so as to release also the hill hold. The inclination a is learning controlled to set the refastening necessary time tC in an adequate scope and while the inclination b is preset to a value to complete the release of the band brake most rapidly within the scope to generate no shock.