Brushless DC motor

Electricity: motor control systems – Specific application: – Hand tool

Reexamination Certificate

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

C318S720000, C318S724000

Reexamination Certificate

active

07058291

ABSTRACT:
A system and method for reducing the cost of producing a brushless DC motor (58) is presented. The brushless DC motor (58) provides higher power density and efficiency with an increased tool run time. The brushless DC motor (58) includes a rotor assembly (72) that has an unmagnetized permanent magnet (74) affixed to a shaft. The permanent magnet (74) remains unmagnetized until the motor is partially assembled. A plurality of coils (94) for producing a magnetic field are wound about the rotor assembly (72). The coils (94) include end turns that enclose the rotor assembly (72) such that the rotor assembly (72) is not removable. Since the windings (94) are wound with the rotor assembly (72) already enclosed, the windings (94) do not require large end coils to allow subsequent insertion of the rotor (72). Minimizing the end coils reduces the length of wire required per turn, thereby reducing the resistance of the winding (94). Also, since the permanent magnet (74) is unmagnetized when the coils (94) are wound around the rotor assembly (72) the winding process is simplified by not coupling energy into the wire which would influence the winder operation. The wound assembly is inserted into a stator stack (96) comprised of magnetic material that provides a magnetic flux return path for the magnetic flux generated by the permanent magnet (74). Using an unmagnetized permanent magnet (74) facilitates easy insertion of the wound assembly into the stator stack (96), reduces the accumulation of magnetic debris during the manufacturing process, and permits the motor assembly to be sealed prior to magnetizing the permanent magnet (74).

REFERENCES:
patent: 4130769 (1978-12-01), Karube
patent: 4228384 (1980-10-01), Arnold et al.
patent: 4547713 (1985-10-01), Langley et al.
patent: 4745345 (1988-05-01), Petersen
patent: 4755699 (1988-07-01), Schmider
patent: 4873463 (1989-10-01), Jones
patent: 4883997 (1989-11-01), De Cesare
patent: 4900968 (1990-02-01), Feigel et al.
patent: 4933581 (1990-06-01), Shramo
patent: 4942323 (1990-07-01), DeCesare
patent: 5197685 (1993-03-01), Banner
patent: 5205721 (1993-04-01), Isaacson
patent: 5221881 (1993-06-01), Cameron
patent: 5382853 (1995-01-01), von der Heide et al.
patent: 5525850 (1996-06-01), Stinson
patent: 5572097 (1996-11-01), Cameron
patent: 5619085 (1997-04-01), Shramo
patent: 5689159 (1997-11-01), Culp et al.
patent: 5714827 (1998-02-01), Hansson
patent: 5729065 (1998-03-01), Fremery et al.
patent: 5731670 (1998-03-01), Galbiati et al.
patent: 5747953 (1998-05-01), Philipp
patent: 5798592 (1998-08-01), Peterson
patent: 5903462 (1999-05-01), Wagner et al.
patent: 5907205 (1999-05-01), Herman et al.
patent: 5909072 (1999-06-01), Muller
patent: 5912519 (1999-06-01), Horner et al.
patent: 6047104 (2000-04-01), Cheng
patent: 6051943 (2000-04-01), Rabin et al.
patent: 6064175 (2000-05-01), Lee
patent: 6080352 (2000-06-01), Dunfield et al.
patent: 6081093 (2000-06-01), Oguro et al.
patent: 6252325 (2001-06-01), Nashiki
patent: 6359401 (2002-03-01), Garcia-Sinclair et al.
patent: 6365998 (2002-04-01), Kech et al.
patent: 2217884 (1973-10-01), None
patent: 2545303 (1977-04-01), None
patent: 2601981 (1977-07-01), None
patent: 2548313 (1980-02-01), None
patent: 3510228 (1986-10-01), None
patent: 3528765 (1987-09-01), None
patent: 3609351 (1987-09-01), None
patent: 3331002 (1988-02-01), None
patent: 3711397 (1988-10-01), None
patent: 3620137 (1989-03-01), None
patent: 3839932 (1990-06-01), None
patent: 39 38 088 (1991-05-01), None
patent: 4026785 (1992-05-01), None
patent: 4122391 (1993-01-01), None
patent: 4440495 (1996-05-01), None
patent: 19502907 (1996-08-01), None
patent: 4432530 (1998-06-01), None
patent: 0107629 (1986-07-01), None
patent: 0170641 (1987-01-01), None
patent: 0268490 (1988-05-01), None
patent: 0254215 (1988-07-01), None
patent: 0107628 (1988-08-01), None
patent: 0419435 (1991-03-01), None
patent: 0490375 (1992-06-01), None
patent: 0688086 (1995-12-01), None
patent: 0848474 (1998-06-01), None
patent: 08484474 (1998-06-01), None
patent: 267757 (1996-11-01), None
patent: 2677571 (1996-11-01), None
patent: 2111773 (1984-12-01), None
patent: 3-190586 (1991-08-01), None
patent: 9068222 (1997-03-01), None
patent: WO 8802192 (1988-03-01), None
patent: WO 9306647 (1993-07-01), None
patent: WO 9638903 (1996-12-01), None
David Halliday, Fundamentals of Physics, John Wiley & Sons, Inc, Fifth Edition, pp. 793, 796-798.
PCT International Search Report PCT/US01/50210, Dec. 19, 2001.
PCT International Search Report PCT/US01/00357, Jan. 4, 2000.
International Search Report, PCT/US01/00357, ISA/US, Feb. 28, 2001.

LandOfFree

Say what you really think

Search LandOfFree.com for the USA inventors and patents. Rate them and share your experience with other people.

Rating

Brushless DC motor does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Brushless DC motor, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Brushless DC motor will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFUS-PAI-O-3662151

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.