BRUSHLESS DIRECT CURRENT ELECTRIC MOTOR WITH REDUCED COGGING TORQUE AND PRODUCTION METHOD THEREOF

• US 20200136486A1
• Filed: 10/28/2019
• Published: 04/30/2020
• Est. Priority Date: 10/29/2018
• Status: Active Grant

• Current Assignee: Circor Industria
• Original Assignee: Circor Industria
• Inventors: ABRAHAM, Sylvain
• Granted Patent: US 11,532,975 B2
• Time in Patent Office: Days
• CPC Class Codes: H02K 1/146 consisting of a generally annular yoke with salient poles
• CPC Class Codes: H02K 1/148 Sectional cores H02K1/141 takes precedence
• CPC Class Codes: H02K 1/185 to outer stators
• CPC Class Codes: H02K 1/278 Surface mounted magnets; Inset magnets
• CPC Class Codes: H02K 15/022 with salient poles or claw-shaped poles
• CPC Class Codes: H02K 15/12 Impregnating, heating or drying of windings, stators, rotors or machines
• CPC Class Codes: H02K 21/16 having annular armature cores with salient poles with homopolar co-operation H02K21/20
• CPC Class Codes: H02K 29/03 with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems

Abstract

The invention relates to a brushless direct current motor, comprising a rotor made up of at least one permanent magnet and a stator comprising at least three partitions (160) radially extending from a circular based cylindrical main body (170), said partitions (160) together defining at least two volumes for receiving at least three coils generating a magnetic field, characterized in that each volume is closed by a wall (170) connecting said partitions (160), and in that said wall comprises, on the face thereof oriented toward the rotor, at least one magnetic restriction zone. A sleeve (4) surrounds the stator and the rotor and comprises at least one deformation zone formed by cutouts (11) adapted to maintain the external geometrical configuration of the sleeve (4) when mounting the constituent elements of the motor.

The invention also relates to a method for manufacturing such a motor.

Claims

1. A brushless direct current motor (1), comprising a rotor (2) made up of at least one permanent magnet, and a stator (3) having at least three partitions (16;

160) radially extending from a circular based cylindrical main body (17;

170), said partitions (16;

160) together defining at least two volumes for receiving at least three coils generating a magnetic field, each volume being closed by a wall, formed by a portion of the body (17;

170), connecting said partitions (16;

160), and said wall comprising, on the face thereof oriented toward the rotor (2), at least one magnetic restriction zone, characterized in that the magnetic restriction zone is formed by at least one zone (18, 19;

180) that is thinner than the wall, and in that a sleeve (4) surrounds the stator (3) and the rotor (2), and in that said sleeve (4) comprises at least one deformation zone formed by cutouts (11) and adapted to maintain the external geometrical configuration of the sleeve (4) when mounting the constituent elements of the motor (1).

2. The motor according to claim 1, wherein the thinner zone is defined by a counterbore (19) or a groove (18;

180) provided in the wall (17;

170).

3. The motor according to claim 1, wherein the magnetic restriction zone is formed by at least one wall portion made of at least one slightly magnetic or non-magnetic material.

4. A method for manufacturing a motor according to claim 1, comprising:

a) stacking metal rings (15;

150) previously machined and configured according to the cross section of the stator (3) with partitions (16;

160) delimiting open volumes for receiving coils, the stacking being carried out to a height corresponding to the desired length of the stator (3);

b) winding copper wires around the partitions (16;

160) on the stack obtained in step a);

c) mounting, using the lacing technique, the stack obtained in step b) in a sleeve (4), with angular indexing by lugs (9) and notches (10) ensuring the positioning of the stack in relation to the sleeve (4);

d) inserting the rotor (2) into the volume for receiving the stator (3);

e) forming the part of the copper wires appearing on the ends or coil;

f) final overmolding of the motor elements with resin.

5. The method according to claim 4, further comprising, after step e) and before step f), an additional step g) of grinding external and internal diameters of the stator is carried out.

6. The method according to claim 4, wherein the sleeve (4) is obtained by stacking rings.

7. The method according to claim 6, wherein the stacking of the rings constituting the sleeve (4) is carried out independently of steps a) to f).