US 12,107,468 B2
Brushless DC motor having high power density for power tool
Barak N. Gohn, Shrewsbury, PA (US); Colin M. Crosby, Baltimore, MD (US); Nicholas J. Lowe, Lutherville-Timonium, MD (US); James R. Clarke, York, PA (US); Daniel F. Heck, Toms River, NJ (US); Michael P. Sikora, Baltimore, MD (US); Christian B. Rogerson, Towson, MD (US); Ryan F. Schroeder, Hampstead, MD (US); Connor T. Mohan, Fallston, MD (US); and Michael D. Grove, Windsor, PA (US)
Assigned to Black & Decker Inc., New Britain, CT (US)
Filed by Black & Decker Inc., New Britain, CT (US)
Filed on Dec. 14, 2021, as Appl. No. 17/550,323.
Claims priority of provisional application 63/129,797, filed on Dec. 23, 2020.
Prior Publication US 2022/0200414 A1, Jun. 23, 2022
Int. Cl. H02K 21/12 (2006.01); H02K 1/16 (2006.01); H02K 1/27 (2022.01); H02K 1/276 (2022.01); H02K 1/28 (2006.01); H02K 3/28 (2006.01); H02K 3/46 (2006.01); H02K 3/52 (2006.01); H02K 5/16 (2006.01); H02K 7/14 (2006.01); H02K 9/06 (2006.01); H02K 11/33 (2016.01); H02K 21/16 (2006.01); B25F 5/00 (2006.01); H02K 11/215 (2016.01)
CPC H02K 21/12 (2013.01) [H02K 1/16 (2013.01); H02K 1/165 (2013.01); H02K 1/27 (2013.01); H02K 1/276 (2013.01); H02K 1/28 (2013.01); H02K 3/28 (2013.01); H02K 3/46 (2013.01); H02K 3/522 (2013.01); H02K 5/16 (2013.01); H02K 7/145 (2013.01); H02K 9/06 (2013.01); H02K 11/33 (2016.01); H02K 21/16 (2013.01); B25F 5/001 (2013.01); H02K 11/215 (2016.01); H02K 2203/03 (2013.01); H02K 2213/03 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A power tool comprising:
a housing; and
a brushless direct-current (BLDC) motor disposed within the housing, the motor comprising:
a rotor assembly including rotor shaft extending along a longitudinal axis and a rotor supporting a plurality of magnets mounted on the rotor shaft;
a stator assembly including a stator comprising a stator core and a plurality of stator teeth radially extending from the stator core and defining a plurality of slots therebetween, and a plurality of stator windings wound on the plurality of stator teeth; and
a circuit board disposed adjacent a rear end of the stator assembly and including a plurality of conductive traces facilitating a one of a parallel or a series connection between at least two stator windings of the plurality of stator windings corresponding to the same phase of the motor,
wherein a ratio of a motor size (Km) constant of the motor to an electrical envelope of the motor is greater than approximately 850 (N·m/√W)/m 3, wherein the electrical envelope of the motor is radially bound by an outer cylindrical boundary of the stator assembly and axially bound by a front radial plane located at a frontmost point of the stator windings and a rear radial plane located at a rearmost point of the circuit board.