Transmission system, especially for automobile vehicles, with wide torque and speed range

Claim 1

Transmission system, especially for automobile vehicles, comprising an input shaft (E), an intermediate shaft (M), an output shaft (S), an input gearbox (P) between the input and intermediate shafts and a main gearbox (B) between the intermediate and output shafts, the input gearbox (P) having a free neutral setting in which the intermediate shaft (M) is decoupled from the input shaft (E) and freely rotatable and a sequence of forward gear ratios in which the intermediate shaft (M) is coupled to the input shaft (E) with a variable forward gear ratio, control means for the input gearbox by means of which the input gearbox (P) is selectively placed in its free neutral setting or in a forward gear with a ratio selected from said sequence of ratios, the main gearbox (B) comprising a clutch (EB), a brake (FB), a double planet gear (TB1, TB2) with four elements (L1, L2, L3, L4) of which a first element (L1) is coupled to the intermediate shaft (M), a second element (L2) is selectively coupled to the input shaft (E) or disengaged by the clutch (EB), a third element (L3) is coupled to the output shaft (S) and the fourth element (L4) is selectively immobilized or released by the brake (FB), said main gearbox (B) having three forward running ranges respectively called slow, intermediate and fast such that in its slow range the second element (L2) is released and the fourth elemenent (L4) is immobilized, in its intermediate range the second element (L2) is coupled to the input shaft (E) and the fourth element (L4) is immobilized in its fast range, the second element (L2) is coupled to the input shaft (E) and the fourth element (L4) is released in its fast range, the transmission system (P, B) having three forward running modes: a slow mode in which the input gearbox (P) is in a forward gear and the main gearbox (B) is in its slow range, an intermediate mode in which the input gearbox (P) is in its free neutral setting and the main gearbox (B) is in its intermediate range and a fast mode in which the input gearbox (P) is in a forward gear and the main gearbox (B) is in its fast range, a change of gear ratio within the sequence of forward gear ratios of the input gearbox (P) increasing the slow forward running ratio of the transmission system (P, B) and decreasing the fast forward running ratio of the transmission system (P, B) and vice versa, the transmission system characterized in that the input gearbox (P) has a reverse gear selected by the input gearbox control means (EP1, EP2, FP1, FP2, FPR), which gives the transmission system on the one hand, a reverse ratio (AR) when the main gearbox (B) is in its slow range and, on the other hand, a highest (11th) forward gear ratio of the transmission system when the main gearbox (B) is in its fast range.