Motor-driven spindle assembly for ring spinning

A motor-driven spindle assembly for a textile ring spinning frame, said assembly comprising a support bolster for attachment to a spindle assembly support rail of a spinning frame, shaft means having one end portion mounted in said support bolster for axial rotation on a central rotational axis and the other end adapted for receipt of a yarn support bobbin, and motor means operatively attached to the shaft means to rotate the same;

• said bolster including an outer housing for fixed attachment to the spindle assembly support rail, means fixed against rotation and mounted in said housing for supporting said one end portion of said shaft means for axial rotation on said central axis and for rotation about axes incrementally angularly varying from said central rotational axis during yarn spinning operations, said means fixed against rotation having an outer end portion surrounding said shaft means and extending out of said bolster housing;
• said motor means comprising a multi-phase brushless DC drive motor for said shaft means having a housing mounted in fixed relation to the bolster in surrounding relation to the axis of rotation of the shaft means, a stator fixedly mounted in said motor housing in surrounding relation to the axis of rotation of the shaft means and having salient poles with phase windings thereon, a rotor mounted on said shaft means for rotation therewith, said rotor being located inside said stator and having salient poles spaced inwardly from and facing the salient poles of the stator;
• and
• means for detecting the relative positions of the rotor and stator during rotor rotation and for providing signals in response to such detection, said detecting means comprising sensed means operatively attached to the rotor for rotation therewith and sensing means fixedly mounted on said outer end portion of said means fixed against rotation and adjacent the path of movement of said sensed means for detecting the passage of the sensed means and for producing signals in response to detection of the sensed means to identify relative rotor/stator positions during operation of the motor, whereby said sensing means is correspondingly incrementally angularly displaceable with said means fixed against rotation, shaft means, and sensed means on the rotor to maintain the same radial distance between the sensing means and the sensed means during the yarn spinning operation.