- A magnetic screw able to be rotated about an axis and/or translated on said axis, said magnetic screw being made up of an even number of magnetic poles and comprising: - a drive transmission member; - a cylindrical rod, the outer lateral surface of the cylindrical rod being made up of a magnetizable material and divided into as many longitudinal screw sectors (6N, 6S) as there are magnetic poles on the magnetic screw, each screw sector (6N, 6S) being formed by one of a surface section and an axial juxtaposition of surface sections, each screw sector (6N, 6S) being separated from an adjacent screw sector (6S, 6N) by an inter-sector space extending along the longitudinal direction of the cylindrical rod, an alternation of recessed parts and projecting parts being formed on each screw sector (6N, 6S), the recessed parts and the projecting parts being arranged helically on the cylindrical rod such that, on a given helix (HN, HS) formed on the outer lateral surface of the cylindrical rod, a recessed part, respectively a projecting part, formed on a screw sector (6N, 6S) extends a projecting part, respectively a recessed part, formed on the other side of the inter-sector space on the adjacent screw sector (6S, 6N); - longitudinal magnetic assemblies in the same number as there are magnetic poles on the magnetic screw, each longitudinal magnetic assembly comprising at least one magnet and each longitudinal magnetic assembly being configured to be arranged in an inter-sector space between two adjacent screw sectors (6N, 6S) and in contact with two adjacent screw sectors (6N, 6S), once in contact, the north face of a longitudinal magnetic assembly polarizing a screw sector into a north screw sector and the south face of said longitudinal magnetic assembly polarizing a screw sector, adjacent to the north screw sector, into a south screw sector; characterized by the fact that: - at least one longitudinal magnetic assembly consists of two wedges made of magnetizable material sandwiching the at least one magnet and protecting the at least one magnet mechanically, the wedges being beveled such that said at least one longitudinal magnetic assembly has a wedge shape in cross-section, and said at least one longitudinal magnetic assembly also has an endpiece at each end; - the magnetic screw further comprises an adjustable support device, secured to the drive transmission member, on which said at least one longitudinal magnetic assembly is movably mounted via the endpieces between a low position remote from the screw sectors (6N, 6S) and a high position in contact with the screw sectors (6N, 6S) in the assembled state of the magnetic screw; and - the magnetic screw is assembled by bonding each surface section making up a screw sector (6N, 6S) to at least one of another screw sector (6N, 6S) and the support device. - a drive transmission member; - a cylindrical rod, the outer lateral surface of the cylindrical rod being made up of a magnetizable material and divided into as many longitudinal screw sectors (6N, 6S) as there are magnetic poles on the magnetic screw, each screw sector (6N, 6S) being formed by one of a surface section and an axial juxtaposition of surface sections, each screw sector (6N, 6S) being separated from an adjacent screw sector (6S, 6N) by an inter-sector space extending along the longitudinal direction of the cylindrical rod, an alternation of recessed parts and projecting parts being formed on each screw sector (6N, 6S), the recessed parts and the projecting parts being arranged helically on the cylindrical rod such that, on a given helix (HN, HS) formed on the outer lateral surface of the cylindrical rod, a recessed part, respectively a projecting part, formed on a screw sector (6N, 6S) extends a projecting part, respectively a recessed part, formed on the other side of the inter-sector space on the adjacent screw sector (6S, 6N); - longitudinal magnetic assemblies in the same number as there are magnetic poles on the magnetic screw, each longitudinal magnetic assembly comprising at least one magnet and each longitudinal magnetic assembly being configured to be arranged in an inter-sector space between two adjacent screw sectors (6N, 6S) and in contact with two adjacent screw sectors (6N, 6S), once in contact, the north face of a longitudinal magnetic assembly polarizing a screw sector into a north screw sector and the south face of said longitudinal magnetic assembly polarizing a screw sector, adjacent to the north screw sector, into a south screw sector; - at least one longitudinal magnetic assembly consists of two wedges made of magnetizable material sandwiching the at least one magnet and protecting the at least one magnet mechanically, the wedges being beveled such that said at least one longitudinal magnetic assembly has a wedge shape in cross-section, and said at least one longitudinal magnetic assembly also has an endpiece at each end; - the magnetic screw further comprises an adjustable support device, secured to the drive transmission member, on which said at least one longitudinal magnetic assembly is movably mounted via the endpieces between a low position remote from the screw sectors (6N, 6S) and a high position in contact with the screw sectors (6N, 6S) in the assembled state of the magnetic screw; and - the magnetic screw is assembled by bonding each surface section making up a screw sector (6N, 6S) to at least one of another screw sector (6N, 6S) and the support device.