Apparatus with a dual-clutch gearbox for a motor vehicle

1 . An apparatus with a dual-clutch gearbox for a motor vehicle, the dual-clutch gearbox comprising:

an input shaft to be connected to a power source of the motor vehicle;

a first shaft extending along a straight axis and carrying a plurality of first gearwheels;

a second shaft carrying a plurality of second gearwheels;

an output shaft to be connected to an axle of the motor vehicle, the output shaft carrying a plurality of third gearwheels meshing with the first gearwheels to form first gears and a plurality of fourth gearwheels meshing with the second gearwheels to form second gears;

a double clutch selectively controllable to connect one of the first and second shafts with the input shaft;

wherein at least a fifth gearwheel of the third gearwheels and a sixth gearwheel of the fourth gearwheels are carried in a rotatable manner with respect to the output shaft,

a first engagement means arranged axially between the fifth gearwheel and the sixth gearwheel and controllable to selectively and mutually exclusive rotationally fix either the fifth gearwheel or the sixth gearwheel to the output shaft;

characterized in that the first engagement means comprises a sleeve element rotationally fixed to the output shaft and axially sliding on the output shaft between the fifth and sixth gearwheels to engage with one of first axial ends of the fifth and sixth gearwheels, the fifth and sixth gearwheels comprising second axial ends axially opposite to the first axial ends, wherein the dual-clutch gearbox comprises a radial bearing supporting the output shaft and arranged axially between the sleeve element and the second axial end of one of the fifth and sixth gearwheels, the radial bearing being arranged in a radially outer position with respect to the first axial end of the one of the fifth and sixth gearwheels, so as to support the output shaft via the first axial end of the one of the fifth and sixth gearwheels.

2 . The apparatus according to claim 1 , further comprising:

a reverse gear comprising at least a seventh and an eighth gearwheel respectively carried in a fixed manner by the second shaft and by the output shaft in a rotatable manner with respect to the output shaft, or respectively carried by the second shaft in a rotatable manner with respect to the second shaft and in a fixed manner by the output shaft; and

a second engagement means controllable to rotationally fix the gearwheel being carried in a rotatable manner, among the seventh and eighth gearwheels, to a related carrying shaft among the second shaft and the output shaft.

3 . The apparatus according to claim 2 , wherein the reverse gear is arranged at an axial end of the dual-clutch gearbox opposite to a further axial end comprising the double clutch according to said straight axis.

4 . The apparatus according to claim 1 , wherein the first shaft and the output shaft carry, respectively, in addition, a ninth gearwheel and a tenth gearwheel meshing with the ninth gearwheel to form a third gear, the ninth gearwheel being carried by the first shaft in a rotatable manner about the first shaft, wherein the tenth gearwheel is carried by the output shaft in a fixed manner with respect to the output shaft or in a rotatable manner with respect to the output shaft.

5 . The apparatus according to claim 4 , further comprising an electric motor-generator having a rotor coupled to the ninth gearwheel via a transmission, such that a rotation of the rotor can be transmitted to the ninth gearwheel and vice versa.

6 . The apparatus according to claim 5 , wherein the tenth gearwheel is carried by the output shaft in a rotatable manner with respect to the output shaft.

7 . The apparatus according to claim 6 , further comprising a second engagement means controllable to rotationally fix the tenth gearwheel to the output shaft.

8 . The apparatus according to claim 7 , wherein the second engagement means comprises a dog-clutch configured to engage the tenth gear on the output shaft.

9 . The apparatus according to claim 4 , wherein the first gears are arranged between the third gear and the second gears according to said straight axis.

10 . The apparatus according to claim 1 , wherein the first gears, and the second gears define respective gear ratios sortable according to an ascending numerical order, so as to correspond to respective degrees of reduction in angular input speed, the degrees of reduction being gradually decreasing, the gear ratios being thus divisible into even ratios and odd ratios according to their numerical order.

11 . The apparatus according to claim 10 , wherein the fifth and sixth gearwheels are part of respective gears defining one of the even ratios and one of the odd ratios.

12 . The apparatus according to claim 11 , wherein the even ratio and the odd ratio related to the fifth and sixth gearwheel are the first and last of the gear ratios according to their ascending numerical order.

13 . The apparatus according to claim 1 , wherein the first engagement means is a synchronizer comprising a synchronizer ring arranged in radial contact with the first axial end of the one of the fifth and sixth gearwheels and axially interposed between the radial bearing and the sleeve element.

14 . The apparatus according to claim 1 , wherein the first and second shafts are coaxial with each other.

15 . A transmission for a motor vehicle, the transmission comprising:

an input shaft configured to be connected to a power source of the motor vehicle;

a first shaft extending along a straight axis and carrying a plurality of first gearwheels, each of the first gearwheels being carried either in a fixed manner by the first shaft, thus defining an element of a set of first rotationally fixed gearwheels, or in a rotatable manner with respect to the first shaft, thus defining an element of a set of first engageable gearwheels;

a second shaft carrying a plurality of second gearwheels, each of the second gearwheels being carried in a fixed manner by the second shaft, thus defining an element of a set of second rotationally fixed gearwheels, or in a rotating manner with respect to the second shaft, thus defining an element of a set of second engageable gearwheels;

an output shaft configured to be connected to an axle of the motor vehicle, the output shaft carrying:

a plurality of third gearwheels meshing with the first gearwheels to form first gear trains, each of the third gearwheels being carried in a fixed manner by the output shaft, thus defining an element of a set of third rotationally fixed gearwheels, or in a rotating manner with respect to the output shaft, thus defining an element of a set of third engageable gearwheels; and

a plurality of fourth gearwheels meshing with the second gearwheels to form second gear trains, each of the fourth gearwheels being carried in a fixed manner by the output shaft, thus defining an element of a set of fourth rotationally fixed gearwheels, or in a rotating manner with respect to the output shaft, thus defining an element of a set of fourth engageable gearwheels;

a double clutch controllable to selectively connect one of the first and second shafts with the input shaft;

at least one first engagement device controllable for rotationally fixing a related first engageable gearwheel of the first engageable gearwheels to the first shaft selectively;

at least one second engagement device controllable for rotationally fixing a related second engageable gearwheel of the second engageable gearwheels to the second shaft selectively;

a third engagement device arranged between one of said third gearwheels and one of said fourth gearwheels and controllable to selectively and mutually exclusive rotationally fix either the said one of said third gearwheels or the said one of said fourth gearwheels to the output shaft; and

a fourth engagement device controllable to rotationally fix another one of said third gearwheels to the output shaft selectively,

characterized in that the third engagement device comprises a sleeve element rotationally fixed to the output shaft and axially sliding on the output shaft between the said one of said third gearwheels and the said one of said fourth gearwheels to engage with one of first axial ends of the said one of said third gearwheels and the said one of said fourth gearwheels, the said one of said third gearwheels and the said one of said fourth gearwheels comprising second axial ends axially opposite to the first axial ends, wherein the double clutch comprises a radial bearing supporting the output shaft and arranged axially between the sleeve element and the second axial end of one of the said one of said third gearwheels and the said one of said fourth gearwheels, the radial bearing being arranged in a radially outer position with respect to the first axial end of the one of the said one of said third gearwheels and the said one of said fourth gearwheels, so as to support the output shaft via the first axial end of the one of the said one of said third gearwheels and the said one of said fourth gearwheels.

16 . The transmission according to claim 15 , wherein the at least one first engagement device, the at least one second engagement device, the third engagement device, and the fourth engagement device each comprise at least one synchronizer.

17 . The transmission according to claim 15 , wherein the at least one first engagement device, the at least one second engagement device, the third engagement device, and the fourth engagement device each comprise at least one clutch.

18 . The transmission according to claim 15 , further comprising a control unit operably connected to the at least one first engagement device, the at least one second engagement device, the third engagement device, and the fourth engagement device, wherein the control unit is operable to selectively fix the first gearwheels, the second gearwheels, the third gear wheels, and the fourth gearwheels to their respective shafts.

19 . A motor vehicle, comprising:

a first power drive;

a second power drive;

a drive axle; and

a transmission, comprising:

an input;

a first shaft carrying a plurality of first gearwheels, each of the first gearwheels being carried either in a fixed manner by the first shaft, thus defining an element of a set of first rotationally fixed gearwheels, or in a rotatable manner with respect to the first shaft, thus defining an element of a set of first engageable gearwheels;

a second shaft carrying a plurality of second gearwheels, each of the second gearwheels being carried in a fixed manner by the second shaft, thus defining an element of a set of second rotationally fixed gearwheels, or in a rotating manner with respect to the second shaft, thus defining an element of a set of second engageable gearwheels;

an output shaft connected to the drive axle, the output shaft carrying:

a plurality of third gearwheels meshing with the first gearwheels to form first gear trains, each of the third gearwheels being carried in a fixed manner by the output shaft, thus defining an element of a set of third rotationally fixed gearwheels, or in a rotating manner with respect to the output shaft, thus defining an element of a set of third engageable gearwheels; and

a plurality of fourth gearwheels meshing with the second gearwheels to form second gear trains, each of the fourth gearwheels being carried in a fixed manner by the output shaft, thus defining an element of a set of fourth rotationally fixed gearwheels, or in a rotating manner with respect to the output shaft, thus defining an element of a set of fourth engageable gearwheels;

a double clutch controllable to selectively connect one of the first and second shafts with the input;

at least one first engagement device controllable for rotationally fixing a related first engageable gearwheel of the first engageable gearwheels to the first shaft selectively;

at least one second engagement device controllable for rotationally fixing a related second engageable gearwheel of the second engageable gearwheels to the second shaft selectively;

a third engagement device arranged between one of said third gearwheels and one of said fourth gearwheels and controllable to selectively and mutually exclusive rotationally fix either the said one of third gearwheels or the said one of fourth gearwheels to the output shaft; and

a fourth engagement device controllable to rotationally fix another one of said third gearwheels to the output shaft selectively,

characterized in that the third engagement device comprises a sleeve element rotationally fixed to the output shaft and axially sliding on the output shaft between the said one of said third gearwheels and the said one of said fourth gearwheels to engage with one of first axial ends of the said one of said third gearwheels and the said one of said fourth gearwheels, the said one of said third gearwheels and the said one of said fourth gearwheels comprising second axial ends axially opposite to the first axial ends, wherein the double clutch comprises a radial bearing supporting the output shaft and arranged axially between the sleeve element and the second axial end of one of the said one of said third gearwheels and the said one of said fourth gearwheels, the radial bearing being arranged in a radially outer position with respect to the first axial end of the one of the said one of said third gearwheels and the said one of said fourth gearwheels, so as to support the output shaft via the first axial end of the one of the said one of said third gearwheels and the said one of said fourth gearwheels.