Self-Starting electric brushless motor having permanent magnet and reluctance poles

A self-starting brushless electric motor, comprising

• a first motor part (11) having a plurality of pole groups arranged in spaced-apart relation in a first pole line,
• a second motor part (16) having a plurality of poles arranged in spaced-apart relation in a second pole line,
• bearing means supporting the first motor part and the second motor part for relative movement with the first pole line confronting the second pole line across an air gap,
• the first pole line and the second pole line comprising a pole system comprising reluctance poles and permanent-magnet poles which are polarized transversely to the air gap, and
• a winding system (15) on the first motor part comprising a winding coil arranged in association with each pole group to produce a magnetic field linking the poles of the first pole line and the second pole line through the pole group upon energization of the coil,
• at least one of the first pole line and the second pole line including a magnetic asymmetry providing a preferential relative direction of movement of the motor parts upon energization of the winding system, at least one of said pole groups comprising an asymmetrical permanent-magnet pole;
• in which said at least one pole group of the first pole line includes at least one symmetrical reluctance pole;
• and
• in which said at least one pole group of the first pole line includes one symmetrical reluctance pole, one asymmetrical reluctance pole and one asymmetrical permanent-magnet pole positioned between the reluctance poles, and in which the second pole line comprises a plurality of substantially evenly spaced asymmetrical identical poles.

A self-starting brushless electric motor, comprising

• a first motor part (11) having a plurality of pole groups arranged in spaced-apart relation in a first pole line,
• a second motor part (16) having a plurality of poles arranged in spaced-apart relation in a second pole line,
• bearing means supporting the first motor part and the second motor part for relative movement with the first pole line confronting the second pole line across an air gap,
• the first pole line and the second pole line comprising a pole system comprising reluctance poles and permanent-magnet poles which are polarized transversely to the air gap,
• a winding system (15) on the first motor part comprising a winding coil arranged in association with each pole group to produce a magnetic field linking the poles of the first pole line and the second pole line through the pole group upon energization fo the coil, a direction of said magnetic field being opposite to a direction of magnetization of the permanent magnets,
• at least one of the first pole line and the second pole line including a magnetic asymmetry providing a preferential relative direction of movement of the motor parts upon energization of the winding system, at least one of said pole groups comprising a pair of reluctance poles and an asymmetrical permanent-magnet pole positioned between and spaced from said reluctance poles;
• and wherein
• the second pole, line includes at least one asymmetrical reluctance pole said at least one pole group of the first pole line includes two symmetrical reluctance poles, the permanent-magnet pole being positioned between the reluctance poles, and in which the second pole line comprises a plurality of substantially evenly spaced asymmetrical identical poles;
• asymmetrical poles on the first motor part and on the second motor part comprise a main pole part and an auxiliary pole part which projects from the main pole part;
• the auxiliary pole parts are of a length, as measured along pole lines, such that when any two poles on the two motor parts are magnetically aligned with one another, the auxiliary pole part of at least one of the magnetically asymmetrical poles on one of the motor parts extends at least to the vicinity of an adjacent pole on the other motor part and preferably slightly overlaps said adjacent pole;
• and
• the auxiliary pole part of at least one of the magnetically asymmetrical poles on one of the motor parts slightly overlaps said adjacent pole.

A self-starting brushless electric motor, comprising

• a first motor part (11) having a plurality of pole groups arranged in spaced-apart relation in a first pole line,
• a second motor part (16) having a plurality of poles arranged in spaced-apart relation in a second pole line,
• bearing means supporting the first motor part and the second motor part for relative movement with the first pole line confronting the second pole line across an air gap,
• the first pole line and the second pole line comprising a pole system comprising reluctance poles and permanent-magnet poles which are polarized transversely to the air gap, and
• a winding system (15) on the first motor part comprising a winding coil arranged in association with each pole group to produce a magnetic field linking the poles of the first pole line and the second pole line through the pole group upon energization of the coil,
• at least one of the first pole line and the second pole line including a magnetic asymmetry providing a preferential relative direction of movement of the motor parts upon energization of the winding system, at least one of said pole groups comprising an asymmetrical permanent-magnet pole;
• in which said at least one pole group of the first pole line includes at least one symmetrical reluctance pole;
• and
• in which said at least one pole group of the first pole line includes one symmetrical reluctance pole, one asymmetrical reluctance pole and one asymmetrical permanent-magnet pole positioned between the reluctance poles, and in which the second pole line includes a plurality of substantially evenly spaced symmetrical permanent-magnet poles.

A self-starting brushless electric motor, comprising

• a first motor part (11) having a plurality of pole groups arranged in spaced-apart relation in a first pole line,
• a second motor part (16) having a plurality of poles arranged in spaced-apart relation in a second pole line.
• bearing means supporting the first motor part and the second motor part for relative movement with the first pole line confronting the second pole line across an air gap,
• the first pole line and the second pole line comprising a pole system comprising reluctance poles and permanent-magnet poles which are polarized transversely to the air gap, and
• a winding system (15) on the first motor part comprising a winding coil arranged in association with each pole group to produce a magnetic field linking the poles of the first pole line and the second pole line through the pole group upon energization of the coil,
• at least one of the first pole line and the second pole line including a magnetic asymmetry providing a preferential relative direction of movement of the motor parts upon energization of the winding system, at least one of said pole groups comprising an asymmetrical permanent-magnet pole;
• in which said at least one pole group of the first pole line comprises a permanent-magnet pole which is placed in an asymmetrical position, and the second pole line comprises a plurality of substantially evenly spaced asymmetrical reluctance poles;
• in which said at least one pole group comprises a pair of reluctance poles, the permanent-magnet pole being placed between the reluctance poles in a position which is asymmetrical with respect to them;
• and
• in which the permanent-magnet pole and the reluctance poles are symmetrical, in which the permanent-magnet pole is displaceable along the pole line from said asymmetrical position to a corresponding asymmetrical position on the opposite side of a line of symmetry between the reluctance poles and in which the reluctance poles of the second pole line comprise a main pole part and an auxiliary pole part at each end of the main pole part.