Gearbox, powertrain for a vehicle comprising said gearbox and vehicle comprising said gearbox

A powertrain for a vehicle, wherein the powertrain comprises:

• a motor having a drive shaft with a pinion;
• and
• a gearbox comprising
• a) an annular support, on which pairs of gears for the input of motion to the gearbox are rotatably and idly supported, the axis of each pair of gears being stationary with respect to the annular support;
• wherein each pair of gears comprises a first gear adapted to receive an input motion, and a second gear;
• wherein the first gear and the second gear being coaxial and angularly coupled to each other to rotate integrally;
• wherein each pair of gears defines a transmission ratio different from the transmission ratios defined by the other pairs of gears;
• wherein the annular support is angularly movable around a selection axis to selectively bring one of said pairs of gears into an angular take-off position of the motion to the gearbox;
• b) a mechanical connection between the second gear of the pair of gears which is in the angular take-off position of the motion to the gearbox, and an output shaft having an axis of rotation parallel to the selection axis or coincident therewith;
• wherein the output shaft passes inside the annular support;
• wherein the mechanical connection comprises a reducer or a multiplier;
• and wherein the reducer or the multiplier comprises a first ring gear meshing with at least the second gear of the pair of gears which is in the angular take-off position of the motion in input to the gearbox;
• wherein the annular support of the gearbox is positioned so as to bring into mesh with the pinion selectively one of the first gears of said pairs of gears, according to the transmission ratio requested, through a rotation of the annular support around the selection axis;
• and wherein the pinion comprises an axis of rotation external to the annular support, so that the motion is input into the gearbox peripherally via the first gear of the pair of gears, which is in the angular take-off position of the motion to the gearbox.

A vehicle comprising:

• a frame;
• at least one driving wheel;
• at least one steered wheel;
• a motor comprising a drive shaft with a pinion rotated by the drive shaft;
• a gearbox interposed between the motor and the driving wheel, wherein the gearbox comprises:
• a) an annular support, on which pairs of gears for the input of motion to the gearbox are rotatably and idly supported, the axis of each pair of gears being stationary with respect to the annular support;
• wherein each pair of gears comprises a first gear adapted to receive an input motion, and a second gear;
• wherein the first gear and the second gear being coaxial and angularly coupled to each other to rotate integrally;
• wherein each pair of gears defines a transmission ratio different from the transmission ratios defined by the other pairs of gears;
• wherein the annular support is angularly movable around a selection axis to selectively bring one of said pairs of gears into an angular take-off position of the motion to the gearbox;
• b) a mechanical connection between the second gear of the pair of gears which is in the angular take-off position of the motion to the gearbox, and an output shaft having an axis of rotation parallel to the selection axis or coincident therewith;
• wherein the output shaft passes inside the annular support;
• wherein the mechanical connection comprises a reducer or a multiplier;
• and wherein the reducer or the multiplier comprises a first ring gear meshing with at least the second gear of the pair of gears which is in the angular take-off position of the motion in input to the gearbox;
• wherein the pinion of the drive shaft is placed outside the annular support of the gearbox;
• and wherein the annular support is adapted to take a plurality of angular positions, such that in each angular position a respective pair of gears is in active position, with the respective first gear in take-off with the pinion of the drive shaft.