Cooling arrangement for an electric machine, and electric machine

Patent metadata

Field	Value
Publication number	US-11527939-B2
Application number	US-202016877989-A
Country	US
Kind code	B2
Filing date	May 19, 2020
Priority date	May 20, 2019
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

A cooling arrangement for an electric machine ( 1, 1 a, 1 b ) includes a rotatably mounted rotor shaft ( 2 ). A rotatably mounted hollow shaft ( 11 ) is mounted coaxially to the rotor shaft ( 2 ) and rotationally fixed to the rotor shaft ( 2 ). A hollow shaft inner side ( 12 ) is spaced apart from a rotor shaft outer side ( 5 ) in a radial direction (R) in order to form an annular gap ( 14 ). At least one cooling duct for a cooling lubricant includes a hollow shaft duct ( 18 ), a feed duct ( 20 ), and an outlet duct ( 25 ). The feed duct ( 20 ) opens into the hollow shaft duct ( 18 ) in order to feed the cooling lubricant to the hollow shaft duct ( 18 ). The outlet duct ( 25 ) extends from the hollow shaft duct ( 18 ) to the annular gap ( 14 ) in order to release the cooling lubricant from the hollow shaft duct ( 18 ) into the annular gap ( 14 ).

First claim

The invention claimed is:

1. A cooling arrangement for a heat-generating, rotating component of an electric machine ( 1 , 1 a , 1 b ), comprising:
a rotor shaft ( 2 ) extending in an axial direction (A) along an axis of rotation (D), a rotor shaft outer side ( 5 ) of the rotor shaft ( 2 ) extending in the axial direction (A), each of a first front-end ( 31 ) of the rotor shaft ( 2 ) and a second front-end ( 26 ) of the rotor shaft ( 2 ) positioned at a respective end of the rotor shaft ( 2 ) in the axial direction (A);
a rotatably mounted hollow shaft ( 11 ) mounted coaxially to the rotor shaft ( 2 ) and rotationally fixed to the rotor shaft ( 2 ), a hollow shaft inner side ( 12 ) of the hollow shaft ( 11 ) facing the rotor shaft outer side ( 5 ), a hollow shaft outer side ( 13 ) of the hollow shaft ( 11 ) positioned opposite the hollow shaft inner side ( 12 ), the hollow shaft inner side ( 12 ) spaced apart from the rotor shaft outer side ( 5 ) in a radial direction (R) in order to form an annular gap ( 14 );
at least one cooling duct for a cooling lubricant, the at least one cooling duct comprising a hollow shaft duct ( 18 ), a feed duct ( 20 ), and an outlet duct ( 25 ),
wherein the hollow shaft duct ( 18 ) is positioned between the hollow shaft inner side ( 12 ) and the hollow shaft outer side ( 13 ) and extends in the axial direction (A),
wherein the feed duct ( 20 ) opens into the hollow shaft duct ( 18 ) in order to feed the cooling lubricant to the hollow shaft duct ( 18 ), and
wherein the outlet duct ( 25 ) extends from the hollow shaft duct ( 18 ) to the annular gap ( 14 ) in order to release the cooling lubricant flowing through the hollow shaft duct ( 18 ) into the annular gap ( 14 ).

2. The cooling arrangement of claim 1 , wherein the hollow shaft duct ( 18 ) extends in the axial direction (A) parallel to the hollow shaft outer side ( 13 ).

3. The cooling arrangement of claim 1 , wherein the feed duct ( 20 ) is arranged facing the first front-end ( 31 ) and the outlet duct ( 25 ) is arranged facing the second front-end ( 26 ).

4. The cooling arrangement of claim 1 , further comprising a transmitter wheel ( 3 ) with a distribution duct ( 37 ) for the cooling lubricant, a first rotor shaft-facing side of the transmitter wheel ( 3 ) arranged at the first front-end ( 20 ) of the rotor shaft ( 2 ) and rotationally fixed to the first front-end ( 20 ) of the rotor shaft ( 2 ), a second side of the transmitter wheel ( 3 ) facing away from the rotor shaft ( 2 ) and positioned opposite the first rotor shaft-facing side of the transmitter wheel ( 3 ), the distribution duct ( 37 ) arranged in the transmitter wheel ( 3 ), the distribution duct ( 37 ) open toward the second side of the transmitter wheel ( 3 ).

5. The cooling arrangement of claim 4 , further comprising:
a rotationally fixed bearing cover ( 4 ) for mounting the transmitter wheel ( 3 ), the bearing cover ( 4 ) arranged on the second side of the transmitter wheel ( 3 ), the bearing cover ( 4 ) comprising a passage that extends in the axial direction (A) and is adjacent the distribution duct ( 37 ); and
a hydraulic connecting bush ( 40 ) and a hydraulic screw connection ( 41 ), the hydraulic connecting bush ( 40 ) arranged in the passage, the hydraulic screw connection ( 41 ) clamped to the hydraulic connecting bush ( 40 ) such that the hydraulic screw connection ( 41 ) forms a fluid connection with the distribution duct ( 37 ) via the hydraulic connecting bush ( 40 ).

6. The cooling arrangement of claim 5 , wherein the hydraulic screw connection ( 41 ) is L-shaped.

7. The cooling arrangement of claim 4 , further comprising a rotationally fixed bearing cover ( 4 ) for mounting the transmitter wheel ( 3 ), the bearing cover ( 4 ) arranged on the second side of the transmitter wheel ( 3 ), the bearing cover ( 4 ) comprising a continuous, L-shaped bearing cover bore ( 23 ) fluidically connected to the distribution duct ( 37 ) such that the cooling lubricant is flowable into the distribution duct ( 37 ) via the bearing cover bore ( 23 ).

8. The cooling arrangement of claim 1 , wherein the feed duct ( 20 ) is a continuous bore through the transmitter wheel ( 3 ) and the hollow shaft ( 11 ), the bore intersecting the hollow shaft duct ( 18 ) at a first point of intersection (S 1 ) such that the cooling lubricant is flowable from the feed duct ( 20 ) into the hollow shaft duct ( 18 ), the continuous bore comprising a seal to block leakage of the cooling lubricant at the hollow shaft outer side ( 13 ).

9. The cooling arrangement of claim 1 , wherein the outlet duct ( 25 ) is a continuous bore through the hollow shaft ( 11 ), the continuous bore intersecting the hollow shaft duct ( 18 ) at a second point of intersection (S 2 ) such that the cooling lubricant is flowable from the hollow shaft duct ( 18 ) into the annular gap ( 14 ) via the outlet duct ( 25 ), the continuous bore comprising a seal to block leakage of the cooling lubricant at the hollow shaft outer side ( 13 ).

10. The cooling arrangement of claim 1 , further comprising multiple cooling ducts distributed over a circumference of the hollow shaft ( 11 ), the multiple cooling ducts spaced equidistantly from one another.

11. The cooling arrangement of claim 1 , wherein the hollow shaft outer side ( 13 ) comprises a cylindrical lateral surface.

12. The cooling arrangement of claim 11 , wherein the cylindrical lateral surface comprises multiple longitudinal grooves ( 32 ) arranged in parallel to one another and extending along the axial direction (A).

13. The cooling arrangement of claim 12 , wherein the multiple parallel longitudinal grooves ( 32 ) are uniformly distributed over a circumference of the hollow shaft outer side ( 13 ).

14. An electric machine ( 1 , 1 a , 1 b ), comprising the cooling arrangement of claim 1 and a rotor ( 27 ) mounted coaxially to the hollow shaft ( 11 ), the rotor ( 27 ) rotationally fixed to the hollow shaft ( 11 ).

15. A method for cooling the rotor in the electric machine ( 1 , 1 a , 1 b ) of claim 14 , the method comprising:
guiding cooling lubricant out of a cooling lubricant sump with a cooling lubricant line to a bearing cover ( 4 );
flowing the cooling lubricant into the distribution duct ( 37 ) via the bearing cover ( 4 ), and flowing the cooling lubricant through the distribution duct ( 37 ) to at least one cooling duct;
flowing the cooling lubricant into the at least one cooling duct, which is fluidically connected to the distribution duct ( 37 ), and flowing the cooling lubricant through the at least one cooling duct to the annular gap ( 14 );
flowing the cooling lubricant into the annular gap ( 14 ), which is fluidically connected to the at least one cooling duct, and flowing the cooling lubricant through the annular gap ( 14 ) to a return duct ( 30 ); and
flowing the cooling lubricant into the return duct ( 30 ) and guiding the cooling lubricant to the cooling lubricant sump fluidically connected to the return duct ( 30 ).

Assignees

• Zahnradfabrik Friedrichshafen

Inventors

• Lang Martin
• Auer Thomas
• Paulik Sebastian
• Wendl Harald
• Obermaier Gerhard
• Lang Maria

Classifications

• H02K2205/09

  Machines characterised by drain passages or by venting, breathing or pressure compensating means · CPC title

• H02K1/32 Primary

  with channels or ducts for flow of cooling medium · CPC title

• H02K5/1732

  radially supporting the rotary shaft at both ends of the rotor (H02K5/1737 takes precedence) · CPC title

• H02K7/003

  Couplings; Details of shafts (means for mounting rotors on shafts H02K1/28) · CPC title

• H02K7/083

  radially supporting the rotary shaft at both ends of the rotor (H02K7/086, H02K7/09 take precedence) · CPC title