Electric motor

Patent metadata

Field	Value
Publication number	US-9806588-B2
Application number	US-201214381692-A
Country	US
Kind code	B2
Filing date	Feb 28, 2012
Priority date	Feb 28, 2012
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

An electric motor comprising a rotor which has a plurality of permanent magnets arranged along a circumferential direction, a stator arrangement with a winding arrangement which surrounds, at least in parts, the permanent magnets. Said stator arrangement comprises a first stator having a plurality of windings and the stator arrangement comprises a second stator, the windings of the first and second stators being embodied, respectively as frame-shaped coils, said coils of the first stator being arranged in the radial direction on the outside of the permanent magnets, the coils of the second stator being arranged in the radial direction inside the permanent magnets, and the coils are arranged along the winding axis thereof in the radial direction and the permanent magnets are arranged along the magnetization direction thereof in the radial direction.

First claim

The invention claimed is:

1. An electric motor comprising:
a rotor which rotates about an axis of rotation and has a plurality of permanent magnets arranged along a circumferential direction with respect to the axis of rotation, the permanent magnets each having a magnetization direction in a radial direction with respect to the axis of rotation; and
a stator arrangement having first and second stators, the first and second stators each having a plurality of windings and located correspondingly radially outside and radially inside the rotor, the windings of the first and second stators being formed as frame-shaped coils, the coils of the first stator being arranged radially outside the permanent magnets with respect to the axis of rotation, such that the first stator at least partially surrounds the permanent magnets, the coils of the second stator being arranged radially inside the permanent magnets with respect to the axis of rotation, the coils of the first and second stators being wound around respective winding axes, which extend in respective radial directions with respect to the axis of rotation, each öf the coils in the first stator and/or in the second stator having an individual curvature along the circumferential direction of the electric motor,
wherein each of the coils in the first stator and in the second stator have a uniform thickness with a size in the radial direction which is smaller than a size in the circumferential direction and than a size in a direction of the axis of rotation of the rotor,
wherein the coils of the first stator have a different curvature in the circumferential direction than the coils of the second stator so that the coils of the first stator and the coils of the second stator have shapes drawn from different centers and thus are non-concentric relative to one another, and the coils of the first and second stators have a greater spatial extension in the direction of the axis of rotation of the rotor than in the circumferential direction, and the circumferential extension of each of the coils of the first stator located radially outside of the rotor is greater than the circumferential extension of each of the coils of the second stator located radially inside the rotor,
wherein the coils of the second stator located radially inside the rotor have a lower number of windings than the coils of the first stator located radially outside the rotor and are shorter in the circumferential direction that the coils of the first stator, and
wherein the coils of the first stator located radially outside the rotor are formed from a wire having a first cross-sectional area, the coils of the second stator located radially inside the rotor are formed from a wire having a second cross-sectional area, and the first cross sectional area is different from the second cross sectional area.

2. The electric motor as claimed in claim 1 , wherein the permanent magnets are arranged to have alternating magnetization directions around a circumference of the rotor such adjacent permanent magnets have magnetization directions oriented radially oppositely with respect to the axis of rotation.

3. The electric motor as claimed in claim 1 , wherein the permanent magnets are arranged to form a hollow cylinder.

4. The electric motor as claimed in claim 1 , wherein
the first stator is formed from a first number of coils,
the second stator is formed from a second number of coils, and
each of the first number and the second number is a multiple of three.

5. The electric motor as claimed in claim 1 , wherein at least one of the first stator and the second stator has a support structure having a plurality of support elements, around which wires are wound to form the coils.

6. The electric motor as claimed in claim 5 , wherein the support elements each extend radially outwardly from the support structure.

7. The electric motor as claimed in claim 5 , wherein the support structure and the support elements ara manufactured from an electrically insulating material that has a relative permeability of one.

8. The electric motor as claimed in claim 5 , wherein a cross-section of the coils, taken in a direction perpendicular to the winding axis, has a substantially rectangular shape.

Assignees

• Hoffmann Martin
• Huth Gerhard
• Siemens Ag

Inventors

• Hoffmann Martin
• Huth Gerhard

Classifications

• H02K1/278

  Surface mounted magnets; Inset magnets · CPC title

• H02K16/04 Primary

  Machines with one rotor and two stators · CPC title

• H02K3/47

  Air-gap windings, i.e. iron-free windings · CPC title

• H02K3/522

  for generally annular cores with salient poles · CPC title

• H02K7/14

  Structural association with mechanical loads, e.g. with hand-held machine tools or fans (with fan or impeller for cooling the machine H02K9/06) · CPC title