Patent ID: 6698303
Filing Date: 2004-03-02
Classification: F16H,Y10T

Abstract:
An automatic transmission apparatus, for a motor vehicle, adapted to couple an engine shaft (10) and an output shaft (12) together, and comprising two input shafts (18, 20), two clutches (E1, E2) arranged between the engine shaft (10) and the output shaft (12), driving pinions (22, 24) mounted on said input shafts and driven pinions (26) mounted on the output shaft (12), each driven pinion (26) being in constant engagement with a driving pinion (22, 24) and defining a transmission ratio, one of the pinions (22, 24, 26) for each ratio being fixed to the input shafts (18, 20) on which said one of the pinions is mounted while the other pinion (26) for said ratio is freely rotatable free pinion (26) on said output shaft (12), and means for selectively coupling each said free pinion (26) fixedly with said output shaft (12) for engagement of the corresponding transmission ratio, wherein each of said two input shafts (18, 20) and said two clutches (E1, E2), couples one input shaft to the engine shaft (10), with each input shaft carrying at least one driving pinion (22, 24), and wherein the selective coupling means comprise, for at least one free pinion (26), first and second controlled one-way lock-up mechanisms (28), mounted in opposition to each other between the free pinion (26) and said output shaft (12), and each said first and second lock-up mechanisms able to occupy two positions, namely a rest position and a working position in which said first mechanism prevents the free pinion (26) from rotating faster than said output shaft while the second mechanism prevents the free pinion (26) from rotating slower than said output shaft, and actuating means (30, 32) for actuating the lock-up mechanisms (28), said actuating means comprising at least one cam which is displaceable in one of straight line motion and in rotation.