Electric machine having segmented stator

• US 7,592,728 B2
• Filed: 05/07/2007
• Issued: 09/22/2009
• Est. Priority Date: 05/10/2006
• Status: Active Grant

• Current Assignee: Robert M. Jones
• Original Assignee: Robert M. Jones
• Inventors: Jones, Robert M., Lisiecki, Joseph M.
• Primary Examiner(s): Zarroli; Michael C
• Application Number:
  US11/800,716
• Publication Number:
  US 20070296298A1
• Time in Patent Office: 869 Days
• Field of Search: 310/112, 310/113, 310/114, 310/156.25, 310/77, 310/93, 310/49.R
• US Class Current: 310/112
• CPC Class Codes: H02K 1/278 Surface mounted magnets; Inset magnets
• CPC Class Codes: H02K 11/33 Drive circuits, e.g. power electronics H02K11/38 takes precedence
• CPC Class Codes: H02K 16/00 Machines with more than one rotor or stator machines for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts H02K51/00; permanent magnet machines with multiple rotors or stators relatively rotated for vectorially combining the excitation fields or the armature voltages H02K21/029
• CPC Class Codes: H02K 21/16 having annular armature cores with salient poles with homopolar co-operation H02K21/20
• CPC Class Codes: H02K 2213/12 Machines characterised by the modularity of some components
• CPC Class Codes: H02K 29/08 using magnetic effect devices, e.g. Hall-plates, magneto-resistors H02K29/12 takes precedence
• CPC Class Codes: H02K 3/38 around winding heads, equalising connectors, or connections thereto
• CPC Class Codes: H02K 5/04 Casings or enclosures characterised by the shape, form or construction thereof
• CPC Class Codes: H02K 5/18 with ribs or fins for improving heat transfer
• CPC Class Codes: H02K 5/225 Terminal boxes or connection arrangements specially adapted for submersible motors H02K5/132

Abstract

An electric machine, such as a brushless direct current motor, includes a number of stator formed as stator sections. The stator sections are longitudinally offset from each other along a common central axis of the electric machine. The stator sections are magnetically independent of one another, but are electrically driven with offset phases typically in a manner similar to a standard multi-phase motor. The stator sections may be further offset with one another in radial position. The structure of the stator sections provides advantages in terms of efficiency, power consumption, torque, and thermal performance, and can be especially advantageous where a battery is used to power the motor, such as in portable hand tools or driving motors for vehicles.

Claims

1. An electric machine comprising:

a cylindrical stator comprising a plurality of stator sections, each stator section having an associated winding that is magnetically independent of the windings of the other stators, the winding being wound around an inner periphery of each of the plurality of the cylindrical stator sections, the plurality of stator sections being longitudinally offset from each other along a common central axis of the electric machine;

a rotor disposed within the cylindrical stator, the cylindrical stator and rotor configured as a DC brushless motor;

a housing configured to support the cylindrical stator and the rotor; and

a controller supported within the housing and configured to provide a separate driving signal to each stator section.

2. An electric machine according to claim 1, wherein the rotor comprises a plurality of rotor sections, each being magnetically independent of the other rotor sections.

3. An electric machine according to claim 2, wherein:

the separate driving signal provided to each stator has a different electrical phase with respect to the driving signals for the other stator sections.

4. An electric machine according to claim 2, wherein each of the plurality of rotor sections electromagnetically interacts with a corresponding one of the plurality of stator sections.

5. An electric machine as in claim 1, wherein the stator sections are wire wound.

6. An electric machine as in claim 1, wherein the stator sections comprise blade sections.

7. The electric machine of claim 6 further comprising:

one or more interconnect disks coupled to the blade sections at each stator section; and

tabs electrically coupled to at least one of the one or more interconnect disks at each stator section, the tabs associated with each stator section configured to transmit the driving signal from the controller to the associated stator section.

8. An electric machine according to claim 2, wherein the rotor comprises a plurality of permanent magnets in each of the rotor sections, the plurality of permanent magnets in at least one of the rotor sections having a different magnetic polarity sequence from the plurality of permanent magnets in another of the rotor sections.

9. A stator comprising:

a first stator portion;

a second stator portion;

a third stator portion;

wherein each of the first through third stator portions are longitudinally offset from one another along a common central axis thereof;

wherein each of the first through third stator portions further include associated blade sections and one or more interconnect disks being electrically and magnetically independent relative to the remainder of the first through third stator portions; and

one or more tabs electrically coupled to at least one of the one or more interconnect disks at each stator section, the tabs also electrically coupled between the one or more interconnect disks and the blade sections.

10. The stator of claim 9, wherein each of the first through third stator portions is generally associated with an operating phase of an electric motor.

11. The stator of claim 9, wherein at least one of the first through third stator sections is generally cylindrical.

12. The stator of claim 9, wherein at least one of the first through third stator portions comprises a back iron.

13. The stator of claim 9, wherein at least one of the first through third stator portions comprises a plurality of laminated disks.

14. The stator of claim 9, wherein the first through third stator sections are all generally cylindrically shaped.

15. The stator of claim 9, wherein at least one of the stator portions is used for one function of an electric motor, while another of the plurality of stator portion is used for a different function.

16. The stator of claim 15, wherein at least one function is selected from the group consisting of power generation, energy generation, and braking.

17. The stator of claim 9, further comprising an insulating member being disposed between at least the first stator portion and the second stator portion.

18. The stator of claim 9, further comprising a second insulating member between the second stator portion and the third stator portion.

19. The stator of claim 9 further comprising:

a housing configured to support the stator portions; and

a controller, supported within the housing, configured to provide a separate driving signal to each stator portion.

20. The stator of claim 19 wherein the separate driving signal provided to each stator portion is provided at a phase different from the phases sent to the remaining stator portions.