US 12,081,096 B2
Electric machine having a fluid cooling device
Michael Hacklberger, Neuburg am Inn (DE); Sebastian Kornexl, Wegscheid (DE); and Manfred Geier, Ruderting (DE)
Assigned to ZF FRIEDRICHSHAFEN AG, Friedrichshafen (DE)
Appl. No. 17/291,230
Filed by ZF FRIEDRICHSHAFEN AG, Friedrichshafen (DE)
PCT Filed Oct. 31, 2019, PCT No. PCT/EP2019/079925
§ 371(c)(1), (2) Date May 4, 2021,
PCT Pub. No. WO2020/094513, PCT Pub. Date May 14, 2020.
Claims priority of application No. 10 2018 218 815.7 (DE), filed on Nov. 5, 2018.
Prior Publication US 2021/0376685 A1, Dec. 2, 2021
Int. Cl. H02K 1/32 (2006.01); H02K 5/173 (2006.01); H02K 5/20 (2006.01); H02K 9/193 (2006.01); H02K 9/197 (2006.01)
CPC H02K 5/1732 (2013.01) [H02K 5/203 (2021.01); H02K 9/193 (2013.01)] 4 Claims
OG exemplary drawing
 
1. An electric machine, comprising:
a stator with a stator core and a stator winding;
a carrier element of the electric machine fixed with respect to the stator;
a rotor shaft;
a first bearing arranged at a first bearing shield;
a rotor with a rotor core which is rotatably supported relative to the stator around an axis by the rotor shaft and the first bearing;
a fluid cooling device comprising:
a cooling tube which is secured to the carrier element and which communicates with a fluid input and extends axially inside of a central recess of the rotor shaft while forming an annular space with respect to the rotor shaft,
wherein the cooling tube is in fluidic communication with the annular space and with a fluid output;
a sealing region with a sealing element provided between the rotor shaft and the carrier element, which at least substantially prevents a passage of fluid into a spatial region of the electric machine located outside of the sealing region when a cooling fluid flows through from the fluid input to the fluid output; and
a second bearing, which is axially spaced apart from the first bearing, is provided between the rotor shaft and a second bearing shield for supporting the rotor, wherein the rotor core extends in a space between the first bearing and second bearing, and
wherein the central recess extends inside the rotor shaft axially at least to the second bearing, and
wherein the rotor shaft has a shaft portion with an output element, the shaft portion projects axially beyond the second bearing, and
wherein the central recess of the rotor shaft axially extends into a region radially bounded by the output element, and cooling fluid flows through an entire extent of the central recess including the region radially bounded by the output element,
wherein the cooling fluid is fluidically separate from a lubricant or coolant located externally to the annular space with respect to the rotor shaft.