Shaft assembly for a gearbox of a vehicle

A shaft assembly for a gearbox, the shaft assembly including:

• a shaft, comprising a front end and a back end coaxial to a rotation axis;
• a gear assembly, comprising a first gearwheel and a second gearwheel secured to each other so as to be locked in rotation relative to each other around the rotation axis;
• a first cylindrical joint, comprising:
• a first cylindrical section, integral to the shaft and coaxial to the rotation axis, and
• a first central opening, integral to the first gearwheel, the first gearwheel being mounted on the shaft coaxially with the rotation axis via the first central opening;
• a second cylindrical joint, comprising:
• a second cylindrical section, integral to the shaft and coaxial to the rotation axis, and
• a second central opening, the second gearwheel being mounted on the shaft coaxially with the rotation axis via the second central opening, wherein the first gearwheel is positioned between the front end and the second gearwheel;
• and
• a spline joint, comprising:
• a first part, integral to the shaft and coaxial to the rotation axis, and
• a second part, integral to the gear assembly, engaged with the first part so that both the first gearwheel and the second gearwheel of the gear assembly are locked in rotation with the shaft around the rotation axis via the spline joint.