Patent Publication Number: US-2022239174-A1

Title: Hybrid rotor module cooling

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a Divisional application which claims priority to U.S. Non-Provisional application Ser. No. 15/496,820, filed Apr. 25, 2017, which claims the benefit of U.S. Provisional Application No. 62/333,516, filed on May 9, 2016, the contents of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Exemplary embodiments pertain to the art of electric motors, and more particularly, to a cooling system for an electric motor having a hybrid rotor module. 
     During operation, electrical energy flow develops heat in rotor and stator portions of an electric motor. Hybrid electric motors may develop additional heat through operation of one or more clutches. Heat can reduce operational performance and an overall operational life of an electric machine. In order to reduce heat build up, coolant is typically passed through the electric motor. Coolant may take the form of a fluid such as air, water or oil. 
     BRIEF DESCRIPTION OF THE INVENTION 
     Disclosed is an electric machine including a housing and a stator mounted to the housing. The stator includes a plurality of laminations, a first end turn and a second end turn. A rotor shaft extends through the housing. A hybrid rotor module is coupled to the rotor shaft. The hybrid rotor module includes a clutch basket including a rotor carrier having a first end, a second end, and an intermediate portion extending therebetween. The first end is radially outwardly offset relative to the second end. One or more clutch assemblies is arranged in the clutch basket. A rotor mounted to the rotor carrier. One or more openings is formed in the rotor carrier. The one or more openings direct coolant onto at least one of the stator, the first end turn, and the second end turn. 
     Also disclosed is a method of cooling a hybrid rotor module of an electric machine includes guiding a volume of coolant into a clutch basket of the hybrid rotor module. The clutch basket includes a first end that is radially outwardly offset relative to a second end. The method also includes passing at least a portion of the volume of coolant to at least one clutch assembly arranged in the clutch basket, directing at least some of the portion of the volume of coolant through a rotor carrier of the clutch basket, and flinging the at least some of the portion of the volume of coolant onto at least one end turn of a stator of the electric machine. 
    
    
     
       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 portion of an electric machine having a hybrid rotor module, in accordance with an aspect of an exemplary embodiment; 
         FIG. 2  depicts a portion of an electric machine having a hybrid rotor module, in accordance with another aspect of an exemplary embodiment; and 
         FIG. 3  depicts a portion of an electric machine having a hybrid rotor module, in accordance with yet another aspect of an 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 aspect of an exemplary embodiment, is illustrated generally at  10  in  FIG. 1 . Electric machine  10  includes a housing  14  supporting a stator  18  having a first end turn  20  and a second end turn  21 . It is to be understood that housing  14  may not directly support stator  18 . For example, stator  18  could be supported by intermediate structure arranged within housing  14 . A rotor shaft  30  extends through housing  14 . Rotor shaft  30  includes an outer surface  32  and may be rotatably supported in housing  14  through a plurality of bearings, one of which is indicated at  34 . 
     Electric machine  10  includes a hybrid rotor module  40  operatively coupled to rotor shaft  30 . Hybrid rotor module  40  includes a clutch basket  44  defined by a first member  47 , a second member  48  and a third member  49 . It is to be understood that first, second and third members  47 - 49  may be individual components, multiple components, or may be formed as a unitary structure. First and second members  47  and  48  extend radially outwardly of outer surface  32  and are joined by third member  49 . In this manner, third member  49  defines a rotor carrier  54 . In the exemplary embodiment shown, rotor carrier  54  includes a first end  59 , a second end  60 , and an intermediate portion  61  extending therebetween. First end  59  is radially offset relative to second end  60 . 
     First, second and third members  47 - 49  define an interior portion  62  housing a first clutch assembly  64 , a second clutch assembly  65  and a third clutch assembly  66 . First clutch assembly  64  may be operable to engage an internal combustion engine (not shown). Second and third clutch assemblies  65  and  66  may be operable to engage a dual clutch transmission. For example, second clutch assembly  65  may be associated with engaging a first gear set (not shown) and third clutch assembly  66  may be associated with engaging a second gear set (also not shown). Thus, in accordance with an exemplary aspect, electric machine  10  may form part of a hybrid electric drive system for a vehicle. 
     A rotor  70  is mounted to rotor carrier  54 . Rotor  70  may include a plurality of laminations (not separately labeled) and is rotated relative to stator  18  to develop an electrical current. In the exemplary embodiment shown, rotor  70  may include a magnet  73 . Magnet  73  may be positioned within rotor  70  so as to define an interior permanent magnet (IPM) rotor, or may be positioned radially outwardly of rotor  70  so as to define a surface permanent magnet (SPM) rotor. It is to be understood that rotor  70  may take the form of an aluminum induction rotor or a copper induction rotor. A coolant passage  77  may extend between rotor  70  and magnet  73 . Coolant passage  77  is fluidically connected with a channel  80  extending radially through rotor  70 . Channel  80  registers with an opening  84  formed in rotor carrier  54 . Opening  84  fluidically connects interior portion  62  with coolant passage  77 . It is to be understood that the number of openings  84 , channels  80  and coolant passages  77  may vary. For example, a number of openings  84 , channels  80  and coolant passages  77  may extend annularly about rotor  70  and rotor carrier  54 . 
     A volume of coolant, such as oil, is passed into interior portion  62 . A portion of the volume of coolant may pass over one or more of first, second and third clutch assemblies  64 - 66 . Some of the coolant passing over the one or more of first, second and third clutch assemblies  64 - 66  and/or another portion of the volume of coolant passes through opening  84  into channel  80 . The coolant flows through coolant passage  77  in a heat exchange relationship with rotor  70  and/or with magnet  73  if so provided. The coolant may then pass from coolant passage  77  via opposing outlets (not separately labeled) and is flung, by for example, centrifugal force, onto first end turn  20  and second end turn  21  providing additional cooling benefits. The coolant may then pass to a drain, through a heat exchanger, and then be redirected back into interior portion  62 . 
     Reference will now follow to  FIG. 2 , wherein like reference numbers represent corresponding parts in the respective views, in describing a rotor  97  in accordance with another aspect of an exemplary embodiment. Rotor  97  is coupled to rotor carrier  54 . A coolant passage  100  extends axially between rotor  97  and rotor carrier  54 . Coolant passage  100  is fluidically connected to interior portion  62  via opening  84 . In this manner, coolant may flow from interior portion  62  into coolant passage  100  and pass, in a heat exchange relationship, through rotor  97 . The coolant may then pass from coolant passage  100  via opposing outlets (not separately labeled) and be flung radially outwardly from coolant passage  100  onto first end turn  20  and second end turn  21  providing additional cooling benefits. 
     Reference will now follow to  FIG. 3 , wherein like reference numbers represent corresponding parts in the respective views, in describing a clutch basket  110  in accordance with an aspect of an exemplary embodiment. Clutch basket  110  includes a first member  112 , a second member  113  and a third member  114 . It is to be understood that first, second and third members  112 - 114  may be individual components, multiple components, or may be formed as a unitary structure. First and second members  112  and  113  extend radially outwardly of outer surface  32  and are joined by third member  114 . In this manner, third member  114  defines a rotor carrier  118 . 
     First, second and third members  112 - 114  define an interior portion  122  housing a first clutch assembly  130 , a second clutch assembly  131  and a third clutch assembly  132 . First clutch assembly  130  may be operable to engage an internal combustion engine (not shown). Second and third clutch assemblies  131  and  132  may be operable to engage a dual clutch transmission. For example, second clutch assembly  131  may be associated with engaging a first gear set (not shown) and third clutch assembly  132  may be associated with engaging a second gear set (also not shown). 
     In accordance with an aspect of an exemplary embodiment, a rotor  140  is mounted to rotor carrier  118 . Rotor  140  is rotated relative to stator  18  to develop an electrical current. In the exemplary embodiment shown, rotor carrier  118  includes a first end  141 , a second end  142 , and an intermediate portion  143  extending therebetween. First end  141  is radially offset relative to second end  142  and includes a first opening  144 . Second end  142  includes a second opening  146 . First opening  144  is arranged near second clutch assembly  131  and second opening  146  is arranged near first clutch assembly  130 . It is to be understood that the location and number of openings formed in rotor carrier  118  may vary. 
     In this manner, a portion of the coolant flowing through interior portion  122  may pass over second clutch assembly  131 , flow through first opening  144  axially outwardly of rotor  140  and be flung radially outwardly onto first end turn  20 . Similarly, another portion of the coolant flowing through interior portion  122  may pass over first clutch assembly  130 , flow through second opening  146  axially outwardly of rotor  140  and be flung radially outwardly onto second end turn  21 . The coolant may also flow in a heat exchange relationship with rotor  140  prior to being distributed to stator  18  and/or first and second end turns  20  and/or  21 . 
     It is to be understood that exemplary embodiments describe systems for proving cooling to components of an electric machine including a hybrid rotor module. Coolant is passed into the hybrid rotor module in a heat exchange relationship with one or more clutch assemblies. The coolant is then passed out from the hybrid rotor module and flung, radially outwardly, onto a stator and/or stator end turns to provide additional cooling benefits. The coolant may pass in a heat exchange relationship with a rotor prior to being distributed to the stator and/or stator end turns. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, element components, and/or groups thereof. 
     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.