Axial brushless DC motor

Patent metadata

Field	Value
Publication number	US-10148152-B2
Application number	US-201615017237-A
Country	US
Kind code	B2
Filing date	Feb 5, 2016
Priority date	Feb 10, 2015
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

An axial brushless DC motor comprising a stator, a rotor including a magnet, a sleeve bushing extending through the stator and including a pair of opposed distal collars, a motor shaft extends through the sleeve bushing, and a pair of opposed bearings are seated in the respective pair of collars and mount the shaft and a rotor for rotation relative to the sleeve bushing and the stator. The bearings are adapted for thrust, radial support/self-alignment, and angular adjustment of the motor shaft. In one embodiment, a stator overmold member includes a central tube that defines the sleeve bushing and includes a stator shorting ring. In one embodiment, a metal pole piece is seated in a cup-shaped magnet with a rim and the magnetic flux travels through the rim of the magnet and through a magnetic flux sensor.

First claim

We clam:

1. An axial brushless DC motor comprising: a stator; a rotor including a magnet; an elongate sleeve bushing extending through the stator, the sleeve bushing defining an interior through-aperture and including first and second opposed distal bearing collars; an elongate shaft extending through the interior through-aperture of the sleeve bushing; a first bearing in the first bearing collar in the sleeve bushing and surrounding a first end of the shaft for allowing the rotation of the shaft relative to the sleeve bushing and the stator; and a second bearing in the second bearing collar in the sleeve bushing and surrounding a second opposed end of the shaft for allowing the rotation of the shaft and the rotor relative to the stator; and a cup defining a receptacle for a disc-shaped pole piece, the disc-shaped pole piece being separate from the magnet, the cup including a base defining a through-hole and the disc-shaped pole piece defining a through-hole and seated against the base of the cup, the elongate shaft extending through the through-hole in the base of the magnet and the disc-shaped pole piece respectively.

2. The axial brushless DC motor of claim 1 , wherein the ball bearing abutment surface on the upper bearing race follows the contour of the balls and the ball bearing abutment surface on the lower bearing race is angled and flat to allow for the combination of thrust, self-centering, radial support, and alignment of the bearing races relative to each other and the shaft and the rotor that is supported by the thrust bearing.

3. The axial brushless DC motor of claim 1 , wherein the ball bearing abutment surface on the upper bearing race is angled and flat and the ball bearing abutment surface on the lower bearing surface follows the contour of the balls to allow the combination of thrust, radial support, and self-alignment of the bearing races relative to each other and the shaft and the rotor that is supported by the thrust bearing.

4. The axial brushless DC motor of claim 1 , further comprising a stator over mold member surrounding the coils and defining the sleeve bushing and a housing for the rotor.

5. The axial brushless DC motor of claim 4 , further comprising a stator shorting ring including respective terminals coupled to the respective coils, the stator shorting ring extending in the stator over mold member.

6. An axial brushless DC motor comprising:
a stator;
a rotor including a magnet;
an elongate sleeve bushing extending through the stator, the sleeve bushing defining an interior through-aperture and including first and second opposed distal bearing collars;
an elongate shaft extending through the interior through-aperture of the sleeve bushing;
a first bearing in the first bearing collar in the sleeve bushing and surrounding a first end of the shaft for allowing the rotation of the shaft relative to the sleeve bushing and the stator;
a second bearing in the second bearing collar in the sleeve bushing and surrounding a second opposed end of the shaft for allowing the rotation of the shaft and the rotor relative to the stator;
the magnet being in the form of a cup defining a receptacle for a disc-shaped pole piece, the disc-shaped pole piece being separate from the magnet, the cup including a base defining a through-hole and the disc-shaped pole piece defining a through-hole and seated against the base of the cup, the elongate shaft extending through the through-hole in the base of the magnet and the disc-shaped pole piece respectively.

7. The axial brushless DC motor of claim 6 further comprising a magnetic flux sensor, the magnet of the rotor including a rim and adapted to generate a magnetic flux, the magnetic flux being adapted to travel through the rim of the magnet and the magnetic flux sensor.

8. The axial brushless DC motor of claim 7 wherein the metal pole piece defines a notch in a peripheral region thereof located adjacent the rim of the magnet for enhancing the density of the magnetic flux in the region of the rim of the magnet and the magnetic flux sensor.

9. An axial brushless DC motor comprising: a stator including a plurality of coils; a stator over mold member surrounding the coils and defining a sleeve bushing including first and second bearing collars and a rotor housing; a rotor including a magnet and located in the rotor housing defined in the stator over mold member; a motor shaft extending through the sleeve bushing of the stator over mold assembly and coupled for rotation to and with the rotor; and first and second bearings seated in the respective first and second bearing collars in the sleeve bushing of the stator over mold assembly and mounting the motor shaft in the motor for rotation with the rotor relative to the stator; and a cup defining a receptacle for a disc-shaped pole piece, the disc-shaped pole piece being separate from the magnet, the cup including a base defining a through-hole and the disc-shaped pole piece defining a through-hole and seated against the base of the cup, the elongate shaft extending through the through-hole in the base of the magnet and the disc-shaped pole piece respectively.

10. An axial brushless DC motor comprising:
a stator;
a rotatable motor shaft extending through the stator; and
a rotor overlying and spaced from the stator and coupled for rotation with the motor shaft, the rotor including a magnet that generates a magnetic flux adapted for sensing by a magnetic flux sensor, the magnet including a rim and the magnetic flux sensor overlying and spaced from the rim of the magnet, the magnetic flux being adapted to travel through the rim of the magnet and the magnetic flux sensor; and
the magnet is in the shape of a cup defining a through-hole and including the rim and further comprising a metal pole piece defining a through-hole and seated in the cup-shaped magnet and including an angled surface formed in a peripheral region of the material of the metal pole piece and located adjacent the rim of the magnet for enhancing the density of the magnetic flux in the region of the rim and the magnetic flux sensor, the motor shaft extending through the through-hole in the magnet and the metal pole piece respectively.

Assignees

• King Yulanda Yhw
• Kolberg David
• Cors Douglas E
• Calkins Scott
• Andrina Eric
• Wolschlager Kevin C
• Stewart William S
• Cts Corp

Inventors

• King Yulanda Yhw
• Kolberg David
• Cors Douglas E
• Calkins Scott
• Andrina Eric
• Wolschlager Kevin C
• Stewart William S

Classifications

• F16C19/163 Primary

  with angular contact · CPC title

• F16C2380/26

  Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators · CPC title

• H02K7/085

  radially supporting the rotary shaft at only one end of the rotor (H02K7/086, H02K7/09 take precedence) · CPC title

• F16C19/543

  in O-arrangement · CPC title

• H02K21/24 Primary

  with magnets axially facing the armatures, e.g. hub-type cycle dynamos · CPC title