Electric motor cartridge for an electrically assisted turbocharger
View Patent ↗An electric motor cartridge comprises a first cartridge housing portion ( 2 ) and a second cartridge housing portion ( 3 ). The cartridge housing portions ( 2, 3 ) are coupled together so as to assembly the electric motor cartridge ( 1 ) by radially and axially positioning a stator ( 4 ) there between.
1. An electric motor cartridge ( 1 ) configured for insertion in a housing and to drive a compressor wheel, the electric motor cartridge ( 1 ) comprising:
a first cartridge housing portion ( 2 );
a second cartridge housing portion ( 3 ); and
a rotor ( 21 );
the cartridge housing portions ( 2 , 3 ) being coupled together so as to assemble the electric motor cartridge ( 1 ) by radially and axially encapsulating a stator ( 4 ) there between,
wherein each cartridge housing portion ( 2 , 3 ) has a semi-shell shape substantially comprised by a bottom portion ( 5 , 6 ) and a cylindrical wall portion ( 7 , 8 ),
wherein at least one of the cylindrical wall portions ( 7 , 8 ) forms a contact ( 14 , 15 ) upon insertion of the assembled electric motor cartridge ( 1 ) in a housing,
wherein one of the bottom portions ( 6 ) forms part of a fixed encapsulation barrier between the stator ( 4 ) and a compressor wheel to be driven by the assembled electric motor cartridge ( 1 ),
wherein each cartridge housing portion ( 2 , 3 ) provides a bore ( 12 , 13 ) in the center of its bottom portion ( 5 , 6 ),
characterized in that
the rotor ( 21 ) has peripheral portions ( 22 , 23 ) inserted through the bores ( 12 , 13 ) of the cartridge housing portions ( 2 , 3 ) and a through hole axially extending through the rotor ( 21 ) and its peripheral portions ( 22 , 23 ) for inserting a shaft ( 34 ) through the rotor ( 21 ).
2. The electric motor cartridge ( 1 ) according to claim 1 , wherein at least one of the cartridge housing portions ( 2 , 3 ) is provided with at least one recess portion ( 9 , 10 ) formed at the inner side of the axial end portion of the cylindrical wall portion ( 7 , 8 ) which extends at least partially in the circumferential direction of the cylindrical wall ( 7 , 8 ) for receiving a projection ( 11 ) of the stator ( 4 ).
3. The electric motor cartridge ( 1 ) according to claim 2 , wherein each cartridge housing portion ( 2 , 3 ) is provided with one recess portion ( 9 , 10 ), wherein the recess portions ( 9 , 10 ) are symmetrically to a plane defined by the abutting tips of the cylindrical wall end portions.
4. The electric motor cartridge ( 1 ) according to claim 3 , wherein at least one of the bottom portions ( 5 , 6 ) is formed at least partly concave inwardly.
5. The electric motor cartridge ( 1 ) according to claim 4 , wherein at least one contact area ( 14 , 15 ) is formed at each of the cartridge housing portions ( 2 , 3 ) so as to be in contact with respective counter contact areas of two housings ( 31 , 19 ) between which the cartridge ( 1 ) is fittable.
6. The electric motor cartridge ( 1 ) according to claim 5 , wherein in at least one of the cartridge housing portions ( 2 , 3 ) a circumferentially extending groove ( 16 ) is disposed so as to receive an o-ring ( 17 ) for sealing between the cartridge housing ( 2 , 3 ) and one of the two housings ( 31 , 19 ) between which the cartridge ( 1 ) is fittable.
7. The electric motor cartridge ( 1 ) according to claim 1 , wherein the cartridge housing ( 2 , 3 ) is made of punched metal, any polymer potted material, any die casting material or any sand casting material.
8. The electric motor cartridge ( 1 ) according to claim 7 , wherein the properties of the material of the cartridge housing ( 2 , 3 ) contributes to heat evacuation and heat protection.
9. The electric motor cartridge ( 1 ) according to claim 1 , wherein the material properties of the cartridge housing contributes to electromagnetic interference protection.
10. The electric motor cartridge ( 1 ) according to claim 1 , wherein at least one of the cartridge housings ( 2 , 3 ) comprises a connector portion ( 20 ) for phases and sensor connections of a compressor motor.
11. The electric motor comprising an electric motor cartridge ( 1 ) according to claim 1 wherein the rotor ( 21 ) is encompassed by the stator ( 4 ).
12. The electric motor according to claim 11 , wherein the rotor ( 21 ) comprises two peripheral portions ( 22 , 23 ) each having a smaller diameter compared to the diameter of a middle portion of the rotor ( 21 ) encompassed by the stator, each peripheral portion ( 22 , 23 ) comprising a circumferential groove ( 24 , 26 ) provided with a piston ring ( 25 , 27 ) for sealing between the inside and the outside of the cartridge ( 1 ), wherein the rotor ( 21 ) is supported at the two peripheral portions ( 22 , 23 ) by the bores ( 12 , 13 ).
13. The electric motor according to claim 11 , further comprising material removal areas on said rotor ( 21 ) providing a unitary rotational mass distribution of the rotor.
14. The electric motor according to claim 11 further comprising a sensor member ( 28 ) for detecting the speed of the rotor ( 21 ).
15. The electric motor according to claim 11 , wherein phases and sensors connections are arranged in the connector portion ( 20 ) such that they plug directly to wiring end connections when assembling the compressor motor.
16. A turbocharger comprising an electric motor according to claim 11 and further comprising
a turbine housing ( 18 ) for accommodating a turbine wheel ( 29 ) driven by exhaust gas;
a center housing ( 31 ) for accommodating a shaft ( 34 ) and the electric motor, the shaft serving as a rotor ( 21 ) of the electric motor and extending from the turbine wheel ( 29 ) through a journal bearing ( 35 ) and the electric motor to a compressor wheel ( 32 );
a compressor housing ( 19 ) for accommodating the compressor wheel ( 32 ); wherein
the compressor wheel ( 32 ) is driven by the turbine wheel ( 29 ) via the shaft ( 34 ) and can additionally be driven by the electric motor, and
the electric motor is accommodated in the center housing ( 31 ) such that the electric motor is firmly fixed by connecting the center housing ( 31 ) to the compressor housing ( 19 ).
17. A turbocharger according to claim 16 , wherein one of the cartridge housing portions ( 2 ) serves as a seal plate on the journal bearing ( 35 ) side and the other cartridge housing portion ( 3 ) serves as a backplate on the compressor wheel ( 32 ) side.
18. A compressor comprising an electric motor according to claim 11 and further comprising
a motor housing for accommodating a shaft and the electric motor, the shaft serving as a rotor of the electric motor and carrying a compressor wheel; and
a compressor housing for accommodating the compressor wheel; wherein
the electric motor is accommodated in the motor housing such that the compressor motor is firmly fixed by connecting the motor housing to the compressor housing.