A linear actuator comprising: a motor having an output shaft for producing a bi-directional rotational output; a casing connected to the motor at a proximal end, the casing having an inner cavity defining at least a joint surface, and a seat surface of greater diameter proximal to the joint surface,; a threaded shaft within the inner cavity of the casing; at least one bearing within the inner cavity in a proximal portion of the casing, the at least one bearing being received in the seat surface; a coupling assembly for coupling the output shaft of the motor to the threaded shaft, the coupling assembly having at least a first coupling component receiving the rotational output from the motor, and at least a second coupling component coupled to the first coupling component for transmission of the rotational output to the threaded shaft, wherein the second coupling component has a cylindrical head, a cylindrical periphery of the cylindrical head being against a surface of an inner race of the bearing; a sliding tube in sliding arrangement with the inner cavity of the casing for moving in translation relative to the casing, a traveling nut in the sliding tube for moving therewith, the traveling nut being operatively engaged to the threaded shaft for converting a rotational motion of the threaded shaft into a translation of the sliding tube; characterized in that the linear actuator is to be used with motion simulators or in motion simulation to displace an occupant of a motion platform relative to the ground or a base, whereby the linear actuator further comprises an end interface at a distal end of the sliding tube, the end interface having connection means to connect the linear actuator to the base or to the ground or to the motion platform, and in that the linear actuator further comprises an integral driven assembly unit comprising the bearing, the threaded shaft, the traveling nut and the sliding tube interconnected to one another so as to be removable by pulling out the integral driven assembly unit as a whole from the inner cavity of the casing via the proximal end after removing the end interface at a distal end of the sliding tube. a motor having an output shaft for producing a bi-directional rotational output; a casing connected to the motor at a proximal end, the casing having an inner cavity defining at least a joint surface, and a seat surface of greater diameter proximal to the joint surface,; a threaded shaft within the inner cavity of the casing; at least one bearing within the inner cavity in a proximal portion of the casing, the at least one bearing being received in the seat surface; a coupling assembly for coupling the output shaft of the motor to the threaded shaft, the coupling assembly having at least a first coupling component receiving the rotational output from the motor, and at least a second coupling component coupled to the first coupling component for transmission of the rotational output to the threaded shaft, wherein the second coupling component has a cylindrical head, a cylindrical periphery of the cylindrical head being against a surface of an inner race of the bearing; a sliding tube in sliding arrangement with the inner cavity of the casing for moving in translation relative to the casing, a traveling nut in the sliding tube for moving therewith, the traveling nut being operatively engaged to the threaded shaft for converting a rotational motion of the threaded shaft into a translation of the sliding tube;