Patent ID: 7898121

Claim:
A gear selector shaft for a vehicle transmission, the shaft being movable in a first axial direction from a neutral position to a first gear engagement position and in a second axial direction from said neutral position to a second gear engagement position, wherein the gear selector shaft incorporates a single phase linear actuator for controlling movement of the gear selector shaft between said first and second gear engagement positions, wherein the linear actuator comprises a stator defining a tubular bore, and wherein said gear selector shaft extends through said tubular bore, wherein the linear actuator further comprises a radially magnetized moving magnet armature which is movable within said stator between first and second stator positions, wherein a portion of the selector shaft forms a core of the armature, and wherein the armature includes radially magnetized permanent magnet annuli arranged on said portion of the selector shaft in opposing magnetic polarity to one another, wherein the stator has a plurality of recesses and a coil mounted in each recess, and further includes portions which define a fixed air gap between the coils and the armature, wherein each coil is positioned to be in concentric association with a respective one of said radially magnetized permanent magnet annuli, wherein the coils are connected to one another to form a single phase coil configured for single phase power input, wherein, upon energization of the single phase coil, the armature is movable axially within the stator between said first and second stator positions, wherein, in a first non-powered state, the armature is at rest in a central position intermediate the first and second stator positions, and the selector shaft is in said neutral position so that the gearbox is in a neutral condition, wherein in order to shift the transmission from its neutral condition into gear, the single phase coil is energized using a voltage of a first polarity, thereby causing an axial shift of the armature from the central position to the first or second stator positions, whereupon the shaft arrives at a respective first or second gear engagement position, and wherein under the application of a voltage of opposite polarity, the armature is controlled to return to its central position.