ELECTRIC MACHINE INCLUDING A SHAFT HAVING A PUMP VANE

Abstract

An electric machine includes an electric machine housing having a first end, a second end, and an interior. A stator is fixedly mounted relative to the electric machine housing. A pump housing is provided at one of the first and second ends. A rotor is rotatably supported relative to the stator. The rotor includes a shaft having a first end that extends to a second end through an uninterrupted intermediate portion having an outer surface. One of the first and second ends extends into the pump housing. At least one vane element projects from the outer surface and is arranged in the pump housing.

Description

BACKGROUND OF THE INVENTION

Exemplary embodiments pertain to the art of electric machines and, more particularly, to an electric machine including a shaft having a pump vane.

Electric machines generally include a housing that encloses a rotor and a stator. The rotor typically includes a rotor hub. The rotor hub supports a plurality of rotor windings that, when acted upon by a magnetic field generated by the stator, cause the rotor to rotate. In some cases, the rotor will include laminations that support permanent magnets. The permanent magnets also interact with the magnetic field supplied by the stator causing the rotor to rotate. The rotor hub is joined to a shaft that is supported by one or more bearings. In some cases, a coolant is introduced into the housing to exchange heat with the rotor, stator and/or other internal components. Coolant may be supplied by an external pump that guides a liquid coolant into and out from the housing. In other cases, the electric machine may include an integral pump that is connected to and driven by the shaft.

BRIEF DESCRIPTION OF THE INVENTION

Disclosed is an electric machine including an electric machine housing having a first end, a second end, and an interior. A stator is fixedly mounted relative to the electric machine housing. A pump housing is provided at one of the first and second ends. A rotor is rotatably supported relative to the stator. The rotor includes a shaft having a first end that extends to a second end through an uninterrupted intermediate portion having an outer surface. One of the first and second ends extends into the pump housing. At least one vane element projects from the outer surface and is arranged in the pump housing.

Also disclosed is a method of pumping liquid in an electric machine. The method includes driving a rotor shaft having a first end that extends to a second end through an uninterrupted intermediate portion having an outer surface, rotating at least one vane element projecting outward from the outer surface in a pump housing provided in an electric machine housing, generating a fluid pressure in the pump housing, and urging the fluid from the pump housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:

FIG. 1 depicts a cross-sectional view of an electric machine including a rotor having a shaft provided with at least one vane in accordance with an exemplary embodiment;

FIG. 2 depicts a partial cross-sectional view of the shaft and at least one vane of FIG. 1;

FIG. 3 depicts a partial perspective view of a pump housing and shaft having pump vanes in accordance with an aspect of the exemplary embodiment; and

FIG. 4 depicts a partial perspective view of the shaft having multiple pump vanes in accordance with another aspect of the exemplary embodiment.

DETAILED DESCRIPTION OF THE INVENTION

A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.

An electric machine in accordance with an exemplary embodiment is indicated generally at 2 in FIG. 1. Electric machine 2 includes a housing 4 having an annular side wall 6 that extends from a first end wall 8 to a cantilevered end 9 defining an opening 10. A second end wall or cover 12 is coupled to cantilevered end 9 and extends across opening 10. Annular side wall 6, first end wall 8 and cover 12 collectively define an interior portion 14. Annular side wall 6 includes an inner surface 17. At this point it should be understood that annular side wall 6 may take on many geometries and should not be considered to be limited to being circular.

Housing 4 is shown to include a liquid pump 24 coupled to first end wall 8. Liquid pump 24 is configured to create a pressurized flow of liquid within interior portion 14. For example, liquid pump 24 may generate a flow of coolant such as oil, glycol, or the like within housing 4. Liquid pump 24 includes a pump housing 27 having an inner wall 30. Inner wall 30 defines a pump chamber 32 having a center axis 33. Inner wall 30 is also shown to include an outlet 34 and an inlet 35 that fluidically connects pump chamber 32 and interior portion 14. Pump housing 27 includes a cover 36 that fluidically seals pump chamber 32.

Electric machine 2 is also shown to include a stator 40 arranged on inner surface 17. Stator 40 includes a body or stator core 42 that supports a plurality of stator windings 44 having a first end turn portion 46 and a second end turn portion 47. A rotor assembly 54 is rotatably mounted to housing 4 relative to stator 40. Rotor assembly 54 includes a rotor hub 57 that supports a plurality of rotor laminations 59. Rotor laminations 59 include permanent magnets (not shown). Rotor assembly 54 may alternatively be provided with a rotor core and rotor windings. Rotor hub 57 is coupled to a rotor shaft 62. Rotor shaft 62 is supported to housing 4 through a first bearing 64 provided on first end wall 8 and a second bearing 65 provided on second end wall 12. Rotor shaft 62 includes a first end portion 68 that extends to a second end portion 69 through an uninterrupted intermediate portion 71. The term “uninterrupted” should be construed to describe a rotor shaft that is materially integral from the first end to the second end. “Materially integral” should be understood to mean that intermediate portion 71 is devoid of connections, couplings or the like. Rotor shaft 62 includes a shaft axis 74 that is off-set relative to center axis 33 of pump chamber 32.

In accordance with an aspect of the exemplary embodiment illustrated in FIG. 2, rotor shaft 62 includes a slot 80 arranged near second end portion 69. Slot 80 is present in pump chamber 32 and is provided with a vane element 83. Vane element 83 includes a vane body 86 having a first end section 89 that extends to a second end section 90 through an uninterrupted, materially integral, intermediate portion 92. Vane element 83 is slidingly received in slot 80 such that upon rotation of rotor shaft 62, one of first and second end sections 89 and 90 contacts inner wall 30 generating a flow of liquid from inlet 35 to outlet 34.

In accordance with another aspect of an exemplary embodiment illustrated in FIG. 3, rotor shaft 62 includes a first slot 110 and a second slot 112. First and second slots 110 and 112 bisect and extend through intermediate portion 71. A first vane element 115 is provided in first slot 110 and a second vane element 118 is provided in second slot 112. First vane element 115 includes a first vane portion 122 and a second vane portion 123 that are coupled through a biasing member 125. Biasing member 125 urges first and second vane portions 122 and 123 outward from rotor shaft 62 and into contact with inner wall 30. Similarly, second vane element 118 includes a first vane portion 128 and a second vane portion 129 coupled through a biasing member 131. In a manner similar to that described above, biasing member 131 urges first and second vane portions 128 and 129 outward from rotor shaft 62 and into contact with inner wall 30.

At this point it should be understood that the exemplary embodiments describe an electric machine including a housing having an integral pump. The integral pump guides liquid, such as coolant into a housing. The coolant flow is generated by one or more vane elements that are provided in a materially integral, uninterrupted shaft. It should also be understood that the arrangement of vane elements may vary. In addition to the vane elements depicted in FIGS. 2 and 3, rotor shaft 62 may be provided with multiple vane elements 150-152 that are axially off-set relative to one another as shown in FIG. 4. In such an arrangement, rotor shaft 62 may include multiple slots, one of which is shown at 160. A biasing member 162 may be provided in slot 160 to urge vane element 150 outward from rotor shaft 62. Biasing member 162 may take the form of a coil spring that is inserted into rotor shaft 62 through an opening 164 that registers with slot 160. A fastener, such as a set screw (not shown), may be employed to retain biasing member 162 in rotor shaft 62. Of course, still other arrangements of vanes may be employed.

While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.

Claims

1. An electric machine comprising:

an electric machine housing having a first end, a second end and an interior;

a stator fixedly mounted relative to the electric machine housing;

a pump housing provided at one of the first and second ends;

a rotor rotatably supported relative to the stator, the rotor including a shaft having a first end portion, that extends to a second end portion through an uninterrupted intermediate portion having an outer surface, one of the first and second ends extends into the pump housing; and

at least one vane element projecting from the outer surface and arranged in the pump housing.

2. The electric machine according to claim 1, wherein the pump housing includes a center axis, the rotor shaft extending into the pump housing off-set from the center axis.

3. The electric machine according to claim 1, wherein the pump housing is provided at the second end.

4. The electric machine according to claim 1, further comprising: a cover extending across the pump housing.

5. The electric machine according to claim 1, wherein the pump housing includes an inlet fluidically exposed to the interior of the electric machine housing.

6. The electric machine according to claim 1, wherein the pump housing includes an outlet fluidically exposed to the interior of the electric machine housing.

7. The electric machine according to claim 1, wherein the at least one vane element comprises a plurality of vane elements.

8. The electric machine according to claim 1, wherein the rotor shaft includes a slot extending through the intermediate portion, the at least one vane element being arranged in the slot.

9. The electric machine according to claim 8, wherein the at least one vane element is slidingly received in the slot.

10. The electric machine according to claim 9, wherein the at least one vane element comprises a first vane element slidingly received in the slot and a second vane element slidingly received in the slot.

11. The electric machine according to claim 10, further comprising: a biasing member positioned between the first vane element and the second vane element.

12. A method of pumping liquid in an electric machine, the method comprising:

driving a rotor shaft having a first end portion that extends to a second end portion through an uninterrupted intermediate portion;

rotating at least one vane element projecting outward from the uninterrupted outer surface in a pump housing provided in an electric machine housing;

generating a fluid pressure in the pump housing; and

urging the fluid from the pump housing.

13. The method of claim 12, wherein rotating the at least one vane element includes rotating the rotor shaft along a shaft axis that is off-set from a central axis of the pump housing.

14. The method of claim 12, wherein rotating the at least one vane element includes rotating at least one vane element that extends through a slot extending through the intermediate portion of the rotor shaft.

15. The method of claim 12, further comprising: sliding the at least one vane element along the slot into contact with an inner wall of the pump housing.

16. The method of claim 15, wherein sliding the at least one vane element along the slot includes sliding a first vane element along the slot and a second vane element along the slot.

17. The method of claim 16, further comprising: biasing the first vane element relative to the second vane element.

18. The method of claim 12, wherein rotating the at least one vane element includes rotating multiple vane elements in the pump housing.

19. The method of claim 12, wherein urging fluid from the pump housing includes guiding fluid into the electric machine housing.

20. The method of claim 12, further comprising: passing fluid from the electric machine housing into the pump housing.