A gearbox comprising a gearshift actuator configured to be driven by an eccentric electric motor, the actuator comprising: - a rotary shaft; - a rotating nut configured to be driven by said electric motor, wherein a rotation axis of the rotating nut is the same as a rotation axis of said rotary shaft; - an actuation member; - a converter adapted to convert a torque of said rotating nut into a translational force and to provide said translational force as actuating force for said gear shift, wherein said converter comprises at least one of the following coupling elements between said rotating nut and said actuation member: a thread, a pin to cam coupling, a pin in a groove coupling, two grooves with rolling elements in-between, another component providing a relative linear movement upon a relative rotation between said rotating nut and said actuation member; - a first gear wheel; - second gear wheel; - wherein a gear shift includes a change of a gear wheel (210, 220) to couple to said rotary shaft, - the gearbox comprising the eccentric electric motor, wherein the electric motor is secured to a frame or housing of the gearshift actuator by a support structure, and a rotation of the electric motor is transferred to the gearshift actuator by a direct connection through a transmission element, - the gearshift actuator comprising a sliding sleeve with a toothed internal surface and configured, upon a translational movement, to couple the first gear wheel or the second gear wheel with the rotary shaft, said sliding sleeve being rotatable relative to said actuation member but axially fixed with respect to said actuation member to enable said gear shift driven by said electric motor, wherein the coupling is provided by the toothed internal surface of the sliding sleeve facing the rotary shaft and toothed external surfaces on rotatory shaft and on the first gear wheel and on the second gear wheel, which are in an interlocking engagement wherein the rotary shaft is either coupled to the first gear wheel or to the second gear wheel, wherein the gearshift actuator is configured to couple or decouple said gear wheels (210, 220) to said rotary shaft in response to an actuation driven by said electric motor. - a rotary shaft; - a rotating nut configured to be driven by said electric motor, wherein a rotation axis of the rotating nut is the same as a rotation axis of said rotary shaft; - an actuation member; - a converter adapted to convert a torque of said rotating nut into a translational force and to provide said translational force as actuating force for said gear shift, wherein said converter comprises at least one of the following coupling elements between said rotating nut and said actuation member: a thread, a pin to cam coupling, a pin in a groove coupling, two grooves with rolling elements in-between, another component providing a relative linear movement upon a relative rotation between said rotating nut and said actuation member; - a first gear wheel; - second gear wheel; - wherein a gear shift includes a change of a gear wheel (210, 220) to couple to said rotary shaft, - the gearbox comprising the eccentric electric motor, wherein the electric motor is secured to a frame or housing of the gearshift actuator by a support structure, and a rotation of the electric motor is transferred to the gearshift actuator by a direct connection through a transmission element, - the gearshift actuator comprising a sliding sleeve with a toothed internal surface and configured, upon a translational movement, to couple the first gear wheel or the second gear wheel with the rotary shaft, said sliding sleeve being rotatable relative to said actuation member but axially fixed with respect to said actuation member to enable said gear shift driven by said electric motor, wherein the coupling is provided by the toothed internal surface of the sliding sleeve facing the rotary shaft and toothed external surfaces on rotatory shaft and on the first gear wheel and on the second gear wheel, which are in an interlocking engagement wherein the rotary shaft is either coupled to the first gear wheel or to the second gear wheel,