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Title:
ELECTRIC MACHINE WITH INTEGRATED CLUTCH
Document Type and Number:
WIPO Patent Application WO/2012/006522
Kind Code:
A2
Abstract:
An electric machine assembly includes a rotor located at a central axis of the electric machine assembly, the rotor includes a rotor cavity that terminates within the rotor. An shaft is operably connected to the rotor and is configured to operatively connect with a component external to the electrical machine. A clutch is located in the rotor cavity such that when the clutch is engaged rotational energy is transferrable from the rotor to the shaft. An electric machine includes a housing and a rotor disposed in the housing. The rotor defines a rotor cavity. A stator is in operable communication with the rotor. A clutch is located in the rotor cavity configured such that, when engaged, rotational energy is transferrable from the rotor to a component external to the electric machine.

Inventors:
CHAMBERLIN BRADLEY D (US)
Application Number:
PCT/US2011/043356
Publication Date:
January 12, 2012
Filing Date:
July 08, 2011
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
REMY TECHNOLOGIES LLC (US)
CHAMBERLIN BRADLEY D (US)
International Classes:
H02K7/10; H02K49/00
Domestic Patent References:
WO2003053734A12003-07-03
Foreign References:
JP2006345685A2006-12-21
JP2003120765A2003-04-23
US20070062774A12007-03-22
JP2003527049A2003-09-09
Attorney, Agent or Firm:
KERNUS, Victor (20 Church Street 22nd Floo, Hartford Connecticut, US)
Download PDF:
Claims:
CLAIMS:

1. An electric machine assembly comprising:

a rotor disposed at a central axis of the electric machine assembly, the rotor including a rotor cavity that terminates within the rotor;

a shaft operably connected to the rotor and configured to operatively connect with a component external to the electrical machine; and

a clutch disposed in the rotor cavity such that when the clutch is engaged rotational energy is transferrable from the rotor to the shaft.

2. The electric machine assembly of claim 1, wherein the rotor comprises:

a rotor shaft disposed at the central axis;

a rotor body; and

a rotor support extending from the rotor shaft to the rotor body.

3. The electric machine assembly of claim 2, wherein the rotor cavity is defined by an outer surface of the rotor shaft, the rotor support and the rotor body.

4. The electric machine assembly of claim 1, further comprising a housing substantially surrounding the rotor.

5. The electric machine assembly of claim 4, wherein the clutch is disposed between the rotor and the housing.

6. The electric machine assembly of claim 4, wherein the housing extends axially inwardly into the rotor cavity thereby defining a housing cavity.

7. The electric machine assembly of claim 6, wherein the clutch is disposed in the housing cavity.

8. The electric machine assembly according to claim 7, wherein the housing defines an axial extent of the electric machine assembly.

9. The electric machine assembly according to claim 1, wherein the clutch is operably coupled to the shaft and configured to selectively engage with the rotor.

10. The electric machine assembly according to claim 1, wherein the rotor defines an axial extent of the electric machine assembly.

11. An electric machine comprising:

a housing;

a rotor disposed in the housing, the rotor, the rotor including a rotor cavity that terminates within the rotor;

a stator in operable communication with the rotor; and a clutch disposed in the rotor cavity configured such that, when engaged, rotational energy is transferrable from the rotor to a component external to the electric machine.

12. The electric machine of claim 11, wherein the rotor comprises:

a rotor shaft disposed at the central axis;

a rotor body; and

a rotor support extending from the rotor shaft to the rotor body.

13. The electric machine of claim 12, wherein the rotor cavity is defined by an outer surface of the rotor shaft, the rotor support and the rotor body.

14. The electric machine according to claim 12, wherein the rotor support and the rotor body form a substantially T-shaped cross-section.

15. The electric machine assembly of claim 11, wherein the clutch is disposed between the rotor and the housing.

16. The electric machine assembly of claim 11, wherein the housing extends inwardly into the rotor cavity thereby defining a housing cavity.

17. The electric machine assembly of claim 16, wherein the clutch is disposed in the housing cavity.

18. .The electric machine assembly according to claim 17, wherein the housing defines an axial extent of the electric machine assembly.

19. The electric machine assembly according to claim 11, wherein the clutch is operably coupled to the shaft and configured to selectively engage with the rotor.

20. The electric machine assembly according to claim 11, wherein the rotor defines an axial extent of the electric machine assembly.

Description:
ELECTRIC MACHINE WITH INTEGRATED CLUTCH

BACKGROUND

[0001] The subject matter disclosed herein relates to electric machines. More specifically, the subject disclosure relates to clutches for electric machines.

[0002] Electric machines, for example, alternators or generators, typically include a rotor located at a central axis of the electric machine. A stator is disposed radially outboard of the rotor and both the rotor and stator are located in a housing of the electric machine. Current is flowed through conductive windings of the stator, which drives rotation of the rotor about the central axis. The rotor is connected to a shaft to drive one or more components outside of the electric machine. One or more clutches are typically located external to the housing to engage and disengage the electric machine from the one or more components. The one or more clutches take up space in, for example, an engine compartment that could otherwise be utilized for other components. The art would well receive a more compact packaging of the electric machine and clutch.

SUMMARY

[0003] An electric machine assembly includes a rotor located at a central axis of the electric machine assembly, the rotor includes a rotor cavity that terminates within the rotor. A shaft is operably connected to the rotor and is configured to operatively connect with a component external to the electrical machine. A clutch is located in the rotor cavity such that when the clutch is engaged rotational energy is transferable from the rotor to the shaft.

[0004] An electric machine includes a housing and a rotor disposed in the housing. The rotor includes a rotor cavity that terminates within the rotor. A stator is in operable communication with the rotor. A clutch is located in the rotor cavity configured such that, when engaged, rotational energy is transferrable from the rotor to a component external to the electric machine.

[0005] These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

[0007] FIG. 1 is a cross-sectional view of an embodiment of an electric machine; and [0008] FIG. 2 is a cross-sectional view of another embodiment of an electric machine.

[0009] The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION

[0010] FIG. 1 illustrates an improved electric machine 10 with an integrated clutch. The electric machine 10 includes a rotor 12 disposed at a central axis 14 of the electric machine 10. A stator 16 is disposed radially outboard of the rotor 12 and comprises one or more conductors 18. The rotor 12 and stator 16 are disposed in a housing 20. When the conductors 18 are energized, the field generated interacts with and drives rotation of the rotor 12 about the central axis 14. At this point it should be understood that electric machine 10 can take on a variety of forms. For example, electric machine 10 could be an AC electric machine, a DC electric machine, an induction machine, an internal permanent magnet machine, a brushed machine, a brushless machine, a synchronous electric machine and the like.

[0011] The rotor 12 is arranged about a rotor shaft 22 located at the central axis 14. At least one rotor support 24 extends outwardly from the rotor shaft 22 and supports a rotor body 26 located along the rotor support 24 at some radial distance from the central axis 14. In some embodiments, the rotor support 24 and the rotor body 26 form a substantially T-shaped cross-section extending from the central axis 14. In other embodiments, rotor support 24 and rotor body 26 could form a U-shaped cross-section. In any event, rotor 12 is constructed such that the stator 16 interacts with the rotor 12 at the rotor body 26, and rotation of the rotor body 26 about the central axis 14 drives rotation of the rotor shaft 22 about the central axis 14. The rotor shaft 22 operably connects to a shaft 28 that is configured to connect with components external to the electric machine 10, for example, an accessory 30.

[0012] A radially outer surface 32 of the rotor shaft 22, the rotor support 24 and the rotor body 26 together define a rotor cavity 34 inside the electric machine 10. The size of the rotor cavity 34 is made possible because of the construction of the rotor 12 having the rotor support 24 and the rotor body 26, with the rotor body 26 located at a radial distance from the central axis 14 to define a radial extent of the rotor cavity 34. Rotor cavity 34 terminates within rotor body 26 at rotor support 24. The rotor cavity 34 is of sufficient size that a clutch 36 is disposed in the rotor cavity 34, integral to the electric machine 10, and is operably connected to the rotor shaft 22. More specifically, clutch 36 is positioned to selectively engage and disengage rotor 12 and shaft 28. In accordance with one aspect of the exemplary embodiment, clutch 36 is operably connected to the shaft 28. In some embodiments, the clutch 36 is located in the rotor cavity 34 such that the rotor 12, not the clutch 36 defines an axial extent of the electric machine 10 / clutch 36 assembly, thus reducing an overall length of an electric machine 10 / clutch 36 assembly.

[0013] In accordance with an exemplary embodiment, clutch 36, when engaged, allows for the transfer of rotational energy from the rotor shaft 22 to shaft 28. For example, if shaft 28 provides an input to electric machine 10, engagement of clutch 36 allows an external machine, such as a motor, to drive rotor 12 to generate electric power. In the event shaft 28 defines an output from electric machine 10, engagement of clutch 36 allows rotational energy from rotor 12 drive an external component. Locating the clutch 36 within the housing of the electric machine 10 in the rotor cavity 34 significantly compacts the packaging of the electric machine 10 and clutch 36 assembly to open up space for other components in, for example, an engine compartment of a motor vehicle.

[0014] Another embodiment is shown in FIG. 2. In this embodiment, the housing 20 of the electric machine 10 extends axially inwardly into the rotor cavity 34 defined by the rotor support 24 and the rotor body 26 at at least one axial end of the electric machine 10. The housing extends axially inwardly such that an exterior surface 38 of the housing 20 defines a housing cavity 40. As shown, in such embodiments, the clutch 36 is disposed in the housing cavity 40 at an exterior of the electric machine 10, rather than directly in the rotor cavity 34 as in the embodiments of FIG. 1 above. In some embodiments, the clutch 36 is located in the housing cavity 40 such that the housing 20, not the clutch 36 defines an axial extent of the electric machine 10 / clutch 36 assembly. Locating the clutch 36 within the housing of the electric machine 10 in the rotor cavity 34 significantly compacts the packaging of the electric machine 10 and clutch 36 assembly to open up space for other components.

[0015] At this point it should be understood that the exemplary embodiments describe a clutch that is internal to a rotor of an electric machine. The clutch is configured to operatively connect the rotor and a shaft. When the rotor and shaft are engaged the electric machine can drive or be driven by an external component. Alternatively, disengaging the clutch interrupts a mechanical link between the rotor and the shaft. The particular configuration allows for the construction of an electric machine having a more compact form factor that can be more readily integrated into a wide array of systems. It should be further understood that the particular type of clutch employed in connection with the exemplary embodiments can vary. For example, the clutch could be a spring clutch, a friction clutch, a wet clutch, a dry clutch, a centrifugal clutch, a hydraulic clutch and the like.

[0016] While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.