Electric machine
AssigneeZF Friedrichshafen AG
InventorUlrich Kehr
Life of this patent
Estimating the term…
Abstract
An electric machine (10) includes a housing (12), a stator (20) fixed within the housing (12), a rotor (30) with a rotor shaft (32), an air gap (24) formed between the rotor (30) and the stator (20), and a cooling device (14) configured for liquid cooling of the electric machine (10). The rotor shaft (32) defines an axial bore (36) in an axial direction, which extends at least partially into the rotor (30). The rotor (30) defines a radially extending air duct (40), which extends from an inner side (42) contacting the rotor shaft (30) to an outer side (44) facing the air gap (24). The rotor shaft (32) defines a bore (46), which is aligned with the air duct (40) such that air is flowable out of the rotor shaft (32) into the air gap (24).
Claims14
An electric machine (10), comprising:
- a housing (12);
- a stator (20) fixed within the housing (12);
- an air supply pump (52);
- a rotor (30) with a rotor shaft (32), an air gap (24) defined between the rotor (30) and the stator (20);
- and
- a cooling device (14) configured for liquid cooling of the electric machine (10),
- wherein the rotor shaft (32) defines an axial bore (36) that extends at least partially into the rotor (30),
- wherein the rotor (30) defines a radially extending air duct (40) that extends from an inner side (42) contacting the rotor shaft (30) to an outer side (44) facing the air gap (24), and
- wherein the rotor shaft (32) defines a bore (46) that is aligned with the air duct (40) such that air is flowable out of the rotor shaft (32) into the air gap (24),
- wherein, when the electrical machine (10) is at a standstill, the air supply pump (52) is operable to pump air into the axial bore (36) of the rotor shaft (32) and through the air duct (40) into the air gap (24) between the rotor (30) and the stator (20) in order to remove cooling liquid from the air gap (24).
A method for generating an air flow in an air gap (24) between a stator (20) and a rotor (30) of an electric machine (10) with a cooling device (14) configured for liquid cooling, the rotor (30) having a rotor shaft (32) with an axial bore (36) that extends into the rotor (30) and with a bore (46) in a radial direction, the rotor (30) having a radially extending air duct (40) that extends from an inner side (42) contacting the rotor shaft (32) to an outer side (44) facing the air gap (24), the bore (46) in the rotor shaft (32) aligned with the air duct (40), the method comprising:
- generating an air flow into the axial bore of the rotor shaft (32);
- guiding the air flow out of the rotor shaft (32) through the bore (46) into the air duct (40) of the rotor (30);
- distributing the air flow in the air gap (24) between the rotor (30) and the stator (20), and
- displacing liquid out of the air gap (24) with the air flow in the air gap (24).
Dependencies are inferred from the claim text.