Brushless linear servomotor

A brushless linear servomotor comprising:

• a first member provided at the surface thereof with magnetic teeth comprising a large number of teeth-like salients and slots arranged lengthwise of said first member at regular pitches, said magnetic teeth being formed on a cylindrical plane of said surface;
• a second member movable along said first member and lengthwise thereof and relative thereto and having at least one magnetic cores, said second member comprising magnetic teeth groups engraved on said magnetic cores at the surfaces thereof opposite to said first member, a plurality of coils wound around said magnetic cores, and a guide means which keeps a constant gap between said magnetic cores and said first member to allow said second member to move smoothly relative to said first member;
• a plurality of non-contact detectors which are connected to said second member, and which detect said salients and slots of said magnetic teeth of said first member and convert the detected results into electric signals so as to thereby output position signals of sine wave form which are different from each other;
• an electronic commutator means for energizing said plurality of coils in the order according to said position signals;
• an electronic scale means which electronically measures the position of said second member relative to said first member by demodulating phase information from a carrier wave signal modulated by said position signals;
• and
• a motor driving circuit which extracts a difference between the output of said electric scale means and the input of position command and provides a current to said plurality of coils according to the magnitude of said difference so as to thereby allow said second member to move relative to said first member.