Solenoid microactuator with magnetic retraction

A magnetic microactuator (100) comprising at least one structure (20) containing at least one coil (6;

• 61;
• 62) arranged to exert, in a powered position, an axial thrust force on a sliding block (30), included in said microactuator (100), in an axial direction (D) in a first direction, up to a front end-of-travel position, corresponding to an abutment bearing between a first bearing surface (21) of said structure (20) and a first abutment surface (31) of said sliding block (30), and wherein in the front end-of-travel position, a front arbor (41), included in said sliding block (30), is protruding from a front face (24) of said structure (20), and, when no said coil (6;
• 61;
• 62) is powered said sliding block (30) is moveable in said axial direction (D) in a second direction opposite to the first direction, and is brought back by purely magnetic means to a rear end-of-travel position corresponding to an abutment bearing between a second bearing surface (22) of said structure (20) and a second abutment surface (32) of said sliding block (30), wherein said sliding block (30) includes at least one permanent magnet (2) joined with a rear arbor (42) aligned with said front arbor (41), or consisting of at least one portion of said rear arbor (42), said at least one permanent magnet (2) generating a magnetic field of revolution around said axial direction (D), which rear arbor (42) is ferromagnetic or magnetised and is arranged to guide the field lines of said magnetic field of revolution substantially in said axial direction (D) through said at least one coil (6;
• 61;
• 62) wherein circulates said sliding block (30), up to a rear end (43) of said rear arbor (42) that tends to cooperate by magnetic attraction with at least one first ferromagnetic restoration element (8), located in the vicinity of a rear face (25) of said structure (20), opposite said front face (24), in order to bring said sliding block (30) back into its said rear end-of-travel position when no said coil (6;
• 61;
• 62) is powered.