Automatic shift device for an epicyclic change-speed gear having means for blocking the engagement of a reverse gear clutch and/or reverse gear brake

摘要

In an automatic shift of an epicyclic change-speed gear, engagement of a reverse gear brake used to shift to reverse gear is blocked until a forward gear clutch used to shift at least one forward gear is disengaged by using the working pressure of the forward gear clutch as a blocking pressure to stress a blocking control element acting upon the valve used for engaging the reverse gear brake.