The automatic transmission consists of automatic starting clutches (51, 53, 55), primary wheels (52, 54, 56) and secondary wheels (57, 58 ,59) of the individual gears, the input shaft (50), output shaft (60), and freewheels (61, 62). Transmission output shaft (50) is mechanically and permanently connected to the input of automatic starting clutch (51) of the first gear. The output of the first automatic starting clutch (51) is mechanically and permanently connected to primary wheel (52) of the first gear and to the input shaft (53) of the second starting clutch. The output of the second automatic starting clutch (53) is mechanically and permanently connected to primary wheel (54) of the second gear and to the input shaft (55) of the third starting clutch. The output of the third automatic starting clutch (55) is mechanically and permanently connected to the primary wheel (56) of the third gear. Freewheels (61, 62) are inserted between the output shaft (60) and the secondary wheels (57, 58) of the individual gears. Secondary wheel (59) of the highest gear is mechanically and permanently attached to output shaft (60).

La présente invention se rapporte à une boîte de vitesses d'un véhicule automobile. Dans l'invention, la boîte de vitesses automatique ou manuelle pilotée automatiquement comporte :

- une pluralité de rapports de démultiplication incluant au moins deux rapports de décollage,

- un calculateur 15 comportant des moyens pour sélectionner automatiquement un rapport de décollage parmi lesdits au moins deux rapports de décollage en fonction des conditions d'utilisation dudit véhicule automobile. L'invention trouve une application immédiate dans le domaine des véhicules automobiles.

A power transmission device for a vehicle successively forms a clutch housing (7) incorporating an engine output portion (20) and a transmission housing (9) incorporating a differential mechanism (64) of drive axles are successively formed lengthwise from an engine (5). A center unit (C1, C2 or C3) serves as an assembly of a center plate (12, 12' or 12") to which a transmission unit or transmission units (U) are attached disposed between the common clutch housing (7) and the common transmission housing (9) so that a transmission unit (U) of center units (C1, C2, C3) is stored inside the clutch housing (7) or the transmission housing (9), and the center units (C1, C2, C3) are constructed such a way that the transmission unit (U) is attached to the center plates (12, 12', 12").

L'invention concerne une boîte de vitesses (110) à arbres parallèles (112, 114, 116), dans laquelle des pignons (118, 120) portés par un arbre primaire (112) lié en rotation au moteur du véhicule engrènent avec des pignons (122, 124, 128, 130, 132) portés par des arbres secondaires (114, 116) liés en rotation à une couronne d'un différentiel pour établir différents rapports de démultiplication, caractérisée en ce que tous les pignons (122, 124, 128, 130, 132, 134) sont montés fous à rotation sur leurs arbres (112, 114, 116), les pignons fous (122, 124, 128) d'un des arbres secondaires (114) étant tous solidaires en rotation, et les pignons (122, 124, 128, 130, 132, 134) portés par les arbres secondaires (114, 116) pouvant y être sélectivement liés par des moyens de crabotage (154, 156, 158), les pignons portés par l'arbre primaire (118, 120 )pouvant être y sélectivement liés par au moins deux embrayages (150, 152) indépendants, pour établir les rapports de démultiplication, les deux embrayages (150, 152) pouvant étant être actionnés alternativement, pour permettre des changements de rapports sans discontinuité du couple aux roues du véhicule.

Application à la réalisation d'une boîte de vitesses robotisée.

A multiple-speed ratio transmission mechanism for an automotive vehicle includes a torque input shaft (12), an output shaft (234), an intermediate shaft, these three shafts rotatably supported on a common axis, and a countershaft (238) mounted parallel to the other shafts. Multiple pinion-gear pairs (26,36,240,246,242,248,244,250) are supported on the three coaxial shafts and countershaft. A planetary gear unit (98), including a sun gear (104), ring gear (100), and a set of planet pinions (106) rotatably supported on a carrier (108), has its input connected to the intermediate shaft and the output connected to the output shaft (234). Synchronisers (52,252,254,256) driveably connect a member of the pinion-gear pairs to one of the shafts.

The invention relates to a multi-speed transmission (10), comprising an input shaft (11), a first driveshaft (13) having at least one driving gearwheel (G1a, G2a, G3a, G4a, G5a), a second driveshaft (14), having a at least two driving gearwheels (GRa, GLa, G1a, G2a, G3a, G34a, G45a), at least one driven shaft (15) with a plurality of gearwheels (Gb, GLb, G1b, G2b, G3b, G4b, G34b, G45b,) on it meshing with the driving gearwheels (GRa, GLa, G1a, G2a, G3a, G4a, G34a, G45a) on said driveshafts (13, 14), said gearwheels (GRa, GLa, G1a, G2a, G3a, G4a, G34a, G45a; Gb, GLb, G1b, G2b, G3b, G4b, G34b, G45b) for forward speeds being engageable to said shafts (13, 14; 15, 16) with a first clutch (C1L) a second clutch (C1R), a third clutch (C2L), a fourth clutch (C2R) and a fifth clutch (C3R) forming a power flow from said driveshafts (13, 14) to the driven shaft (15) with different ratios, a controllable lock-up clutch (C3L) being arranged between the driveshafts (13, 14), connecting said driveshafts (13, 14) with each other, a brake device (40) with controllable slip, a planetary gearset (20) with three links (21, 22, 23), a first (21) of said links being connected to the first driveshaft (13) and the input shaft (11), a second link (22) being connected to the second driveshaft (14), and a third link (23) being kinematically connected to said brake device (40).

A speed ratio (i_PGS) between the second link (22) and the third link (23) for stopped first link (21) has a defined value i_PGS <0, a first gear ratio (i_G1) of the first gearing (GL) on the second driveshaft (14) has a defined value i_G1, a second gear ratio (i_G2) of the first gearing (G1) on the first driveshaft (13) matches the inequality i_G2 >= i_G1/ (1-(1/i_PGS)), a third gear ratio (i_G3) of the second gearing (G2) on the second driveshaft (14) matches the inequality i_G3 < i_G2, a fourth gear ratio (i_G4) of the second gearing (G3) on the first driveshaft (13) matches the inequality i_G4 >= i_G3/ (1-(1/i_PGS)), a fifth gear ratio (i_G5) of the third gearing (G4/5) on the second driveshaft (14) matches the inequality i_G5 < i_G4.

A speed change system for a working vehicle comprises a main transmission (16), a sub transmission (17) and a preliminary transmission (14). The main transmission (16) receives a prime mover power outputted from a prime mover (2), and has plural main speed stages, one of which is selected to transmit the prime mover power (2). The sub transmission (17) is disposed on the downstream of the main transmission (16), and has plural sub speed stages, one of which is selected to transmit a power from the main transmission (16). The preliminary transmission (14) is disposed on the upstream of the main transmission (16), and has plural preliminary speed stages, one of which is selected to transmit the prime mover power (2) to the main transmission (16). An operation for selecting one of the preliminary speed stages can be performed during traveling of the working vehicle.