A linear driving unit comprising: - a linear electric motor formed by a motor housing, which is electrically excited and affixed to a fixed structure, and by a magnetic armature which is coupled to a piston through coupling means and displaced by the electric excitation of the motor housing, in a reciprocating axial movement, said piston, coupling means and magnetic armature defining a compression movable assembly, - a helical resonant spring having an end coupled to the fixed structure and an opposite end coupled to the magnetic armature in order to be displaced by the latter and elastically deformed, in a reciprocating axial movement, and operating as a guide for the axial displacement of the piston and also actuating on the compression movable assembly, jointly with the linear electric motor, - a deformation control device being provided directly and tightly, along and around one or more wire extension(s) of the resonant spring, in respective specific regions which are subject to radial, lateral or torsional deformations upon the reciprocating axial movement of the resonant spring, in order to maintain direct contact with the surface of the wire extension (s) in said specific regions of the resonant spring, producing, during the axial elastic deformation of said resonant spring, a generation of friction with the surface of said wire extension(s) of the resonant spring, and/or a generation of elastic deformation of the deformation control device, caused by said radial, lateral or torsional deformations of the resonant spring, being transmitted to the deformation control device, characterized in that the deformation control device is defined by a semi-tubular coating which surrounds part of the circumferential contour of said wire extension of the resonant spring, maintaining direct contact with the latter, said semi-tubular coating being defined, in a single piece, by a plurality of semi-annular segments which are spaced apart and connected to one another. - a linear electric motor formed by a motor housing, which is electrically excited and affixed to a fixed structure, and by a magnetic armature which is coupled to a piston through coupling means and displaced by the electric excitation of the motor housing, in a reciprocating axial movement, said piston, coupling means and magnetic armature defining a compression movable assembly, - a helical resonant spring having an end coupled to the fixed structure and an opposite end coupled to the magnetic armature in order to be displaced by the latter and elastically deformed, in a reciprocating axial movement, and operating as a guide for the axial displacement of the piston and also actuating on the compression movable assembly, jointly with the linear electric motor, - a deformation control device being provided directly and tightly, along and around one or more wire extension(s) of the resonant spring, in respective specific regions which are subject to radial, lateral or torsional deformations upon the reciprocating axial movement of the resonant spring, in order to maintain direct contact with the surface of the wire extension (s) in said specific regions of the resonant spring, producing, during the axial elastic deformation of said resonant spring, a generation of friction with the surface of said wire extension(s) of the resonant spring, and/or a generation of elastic deformation of the deformation control device, caused by said radial, lateral or torsional deformations of the resonant spring, being transmitted to the deformation control device,