Electric motor having a stator and a rotor

Patent metadata

Field	Value
Publication number	US-9780627-B2
Application number	US-201414257332-A
Country	US
Kind code	B2
Filing date	Apr 21, 2014
Priority date	Apr 30, 2013
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

An electric motor includes a stator, and a rotor which has a rotor shaft. At least one rotor position magnet is disposed on the rotor shaft, and is configured to provide a magnetic signal that can be evaluated, upon a rotation of the rotor shaft, at least for the purpose of determining a respective rotor position of the rotor. At least one carrier is disposed in a rotationally fixed manner on the rotor shaft, and is connected to the at least one rotor position magnet. The carrier includes at least one opening configured to compensate imbalance of the rotor.

First claim

What is claimed is:

1. An electric motor, comprising:
a stator; and
a rotor assembly positioned relative to the stator, the rotor assembly including:
a rotor that includes a rotor shaft,
at least one rotor position magnet disposed on the rotor shaft, the at least one rotor position magnet providing a magnetic signal that is configured to be evaluated to determine a respective rotor position of the rotor upon a rotation of the rotor shaft, and
at least one carrier disposed on the rotor shaft in a rotationally fixed manner, the at least one carrier including at least one opening configured to compensate an imbalance of the rotor assembly,

wherein the at least one carrier is connected to the at least one rotor position magnet, and
wherein a position of the at least one opening is based on the imbalance of the rotor assembly.

2. The electric motor according to claim 1 , wherein the at least one carrier further includes a non-magnetically conducting material.

3. The electric motor according to claim 1 , wherein the at least one carrier further includes brass.

4. The electric motor according to claim 1 , wherein:
a portion of the at least one carrier is configured as a frame-type receiver; and
the at least one rotor position magnet is disposed in the frame-type receiver portion in a rotationally fixed manner.

5. The electric motor according to claim 1 , wherein the at least one rotor position magnet includes a ring magnet.

6. The electric motor according to claim 1 , wherein the at least one opening is formed by a removal of material from the at least one carrier.

7. The electric motor according to claim 1 , wherein the at least one opening is formed via at least one of drilling, milling, and cutting.

8. The electric motor according to claim 1 , wherein the at least one carrier includes a plurality of openings disposed in a circular manner.

9. The electric motor according to claim 1 , wherein the at least one carrier is fastened to the rotor shaft at least via form closure.

10. A hand power tool, comprising:
an electric motor that includes:
a stator, and
a rotor assembly positioned relative to the stator, the rotor assembly including:
a rotor that includes a rotor shaft,
at least one rotor position magnet disposed on the rotor shaft, the at least one rotor position magnet providing a magnetic signal that is configured to be evaluated to determine a respective rotor position of the rotor upon a rotation of the rotor shaft, and
at least one carrier disposed on the rotor shaft in a rotationally fixed manner, the at least one carrier including at least one opening configured to compensate an imbalance of the rotor assembly,

wherein the at least one rotor position magnet is connected to the at least one carrier, and
wherein a position of the at least one opening is based on the imbalance of the rotor assembly.

11. The electric motor according to claim 1 , wherein the at least one opening is formed by a removal of material from the at least one carrier in an amount based on the imbalance of the rotor assembly.

12. The electric motor according to claim 1 , wherein the at least one opening is formed via at least one of drilling, milling, and cutting so as to remove material from the at least one carrier in an amount based on the imbalance of the rotor assembly.

13. The electric motor according to claim 1 , wherein the position of the at least one opening is infinitely variable across a surface portion of the at least one carrier.

14. The electric motor according to claim 13 , wherein the surface portion is an end face of the at least one carrier, the end face oriented perpendicular to and completely encircling the rotor shaft.

15. The electric motor according to claim 13 , wherein the surface portion is a continuous circumferential surface of the at least one carrier, the circumferential surface facing radially away from and completely encircling the rotor shaft.

16. The electric motor according to claim 4 , wherein the frame-type receiver includes a ring-shaped basic body with a circumferential web and a spacer element extending axially from a central region of the basic body.

17. The electric motor according to claim 16 , wherein the at least one rotor position magnet is disposed within a cavity formed by the basic body and the circumferential web, the at least one rotor position magnet disposed entirely within the cavity and surrounded circumferentially by the circumferential web.

Assignees

• Bosch Gmbh Robert

Inventors

• Weller Friedbert
• Nadig Peter
• Dengler Klaus
• Rombach Daniel
• Kloer Bastian

Classifications

• H02K7/145

  Hand-held machine tool · CPC title

• H02K11/215 Primary

  Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements · CPC title

• H02K7/04

  Balancing means · CPC title

• H02K1/27

  Rotor cores with permanent magnets · CPC title

• H02K1/30

  using intermediate parts, e.g. spiders · CPC title