Rotor shaft system with increased stiffness

A vehicle, comprising:

• an electric motor including a rotor;
• and
• a rotor shaft system coupled to the electric motor, the rotor shaft system including:
• a rotor shaft including a first shaft end opposite a second shaft end and having a first segment and a second segment defined between the first shaft end and the second shaft end, the second segment coupled to the rotor;
• a shaft gear defined on the rotor shaft between the first shaft end and the first segment;
• a shaft sleeve coupled to the first segment so as to be disposed between the shaft gear and the rotor, and the shaft sleeve surrounds a portion of the shaft gear;
• a shaft collar coupled to the second segment between the rotor and the second shaft end, and the shaft collar is configured to clamp the rotor and the shaft sleeve to the rotor shaft;
• and
• a lubrication system defined through a portion of the rotor shaft and the shaft sleeve, the lubrication system configured to supply a fluid to at least the portion of the rotor shaft, the shaft sleeve and the electric motor.