Electric motor vehicle traction motor with stator having slot molding and liquid cooled end winding
View Patent ↗An electric motor vehicle traction motor has a motor housing, a liquid-cooled motor stator and a dry running internal motor rotor which is separated fluidically from the motor stator. The motor stator is formed by a stator body with radial stator slots and a plurality of stator coils. The axial phase windings are arranged in the stator slots, and the winding heads of protrude axially out of the stator slots. A slot potted body is made from a potting material and by way of which the stator coil axial phase windings are potted into the stator slots in a fluid-tight manner. The stator coil winding heads are of potting-free configuration and protrude in each case directly into a fluid-tight cooling space. As a result of the omission of a separate split cage, a small air gap is realized and manufacturing costs are reduced.
1. A method for producing an electric vehicle traction motor, the traction motor including (i) a motor housing, (ii) a motor stator having a stator body with laminations and stator slots and a plurality of stator coils, wherein axial phase windings of the stator coils are arranged in the stator slots, and (ii i) an internal motor rotor which is separated fluidically from the motor stator, said method comprising the steps of:
inserting a mold core having radially extending injection channels into a central opening of the motor stator;
following the inserting step, injecting liquid potting material into the stator slots radially from an inside of the stator slots via the radially extending injection channels of the mold core as well as radially from an outside of the stator slots in order to form a slot potted body, such that the injected liquid potting material passes through the stator slots and exits the stator slots to protrude axially out of the stator slots thereby defining an overhanging portion of the slot potted body that overhangs the stator slots and an end-most lamination of the laminations of the stator body, wherein a shoulder is formed at an intersection of the overhanging portion and said end-most lamination of the stator body,
inserting a motor rotor into the central opening of the motor stator, and
installing the motor rotor and the motor stator into a motor housing.
2. The method as claimed in claim 1 , wherein at least one of the stator slots that is disposed in a first lamination of the laminations and between two adjacent lamination sections of the first lamination includes (i) a radially outward portion that is positioned furthest from the rotor and has a first gap dimension defined between the two adjacent lamination sections, (ii) a radially inward portion that is positioned closest to the rotor and has a second gap dimension defined between the two adjacent lamination sections, and (iii) a central portion disposed between the radially outward and inward portions, the central portion having a third gap dimension defined between the two adjacent lamination sections, wherein the third gap dimension is larger than the first and second gap dimensions, and wherein the axial phase windings of the stator coils are arranged in the central portion.
3. The method as claimed in claim 1 , wherein the stator body has a plurality of injection channels which, in each case, connect one of the stator slots to an outer side of the stator body, wherein the injection channels of the stator body are filled with the potting material, and
wherein, for each injection channel of the stator body, the injection channel has a smaller cross-sectional width than the stator slot to which that injection channel is connected.