Patent ID: 7345386
Filing Date: 2008-03-18
Classification: H02K

Abstract:
1. An electric drive unit comprising an electric motor, a motor carrier section ( 5 ) supporting said electric motor, said electric motor ( 3 ) comprising a stator and a rotor mounted for rotation relative to said stator, said electric motor further comprising an electronic control module ( 2 ) including electronic elements ( 21 ) and a cooling body ( 7 ) having at least one cooling surface ( 71 ) in heat transfer contact with said electronic elements ( 21 ), said cooling body ( 7 ) being supported by said stator, said rotor comprising a hub including a radial hub wall ( 32 ) supported for rotation of said rotor relative to said stator about a rotation axle ( 39 ), said hub further including at least one axial cylindrical hub wall ( 411 ) secured circumferentially to said radial hub wall ( 32 ), fan blades ( 42 ) secured to said at least one cylindrical hub wall ( 411 ) for producing a primary working air flow when said rotor rotates, said drive unit comprising a first set of radially elongated air flow holes ( 322 ) extending in said radial hub wall ( 32 ) radially outwardly from said rotation axle ( 39 ) and a second set of air flow holes ( 43 ) positioned in said radial hub wall ( 32 ) radially outwardly of said first set of radially elongated air flow holes ( 322 ), wherein said first and second set of air flow holes ( 43 , 322 ) rotate with said hub, a gap ( 6 ) between an axially inwardly facing edge ( 415 ) of said at least one cylindrical hub wall ( 411 ) and an axially inwardly facing edge ( 513 ) of said motor carrier ( 5 ), said first set of elongated air flow holes ( 322 ) and said second set of air flow holes ( 43 ) communicating with the atmosphere and with said gap ( 6 ) through a hub inner space, and wherein said cooling body ( 7 ) reaches at least partially into said hub inner space for cooling of said electronic elements ( 21 ) by a secondary cooling airflow generated between said first and second set of air flow holes ( 322 , 43 ) and said gap ( 6 ) when said rotor rotates.