ELECTRIC MOTOR VEHICLE TRACTION MOTOR

Abstract

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.

Claims

1. An electric motor vehicle traction motor comprising: a motor housing, a liquid-cooled motor stator comprising a stator body with stator slots and a plurality of stator coils, wherein axial phase windings of the stator coils are arranged in the stator slots, a dry-running internal motor rotor which is separated fluidically from the motor stator, winding heads of the stator coils protruding, in each case, axially out of the stator slots and directly into a fluid-tight cooling space, the winding heads being composed of a potting-free configuration, and a slot potted body, which is composed of a potting material, and by way of which the axial phase windings are potted into the stator slots in a fluid-tight manner.

2. The electric motor vehicle traction motor as claimed in claim 1, the stator slots being open radially inward toward the motor rotor.

3. The electric motor vehicle traction motor as claimed in claim 1, wherein a cylindrical inner circumferential face of the motor stator which delimits a cylindrical air gap between the motor stator and the motor rotor is formed substantially by the stator body.

4. The electric motor vehicle traction motor as claimed in claim 1, wherein a cylindrical inner circumferential face of the motor stator, which delimits a cylindrical air gap between the motor stator and the motor rotor, is formed exclusively by the slot potted body.

5. The electric motor vehicle traction motor as claimed in claim 1, wherein the slot potted body protrudes axially out of the stator slots such that the slot potted body overhangs the stator slots.

6. The electric motor vehicle traction motor as claimed in claim 1, wherein the winding heads are liquid-cooled in the cooling spaces.

7. The electric motor vehicle traction motor as claimed in claim 1, wherein the stator body has a plurality of axial cooling ducts.

8. The electric motor vehicle traction motor as claimed in claim 1, the stator body having a plurality of injection channels which, in each case, connect one of the stator slots to an outer side of the stator body, the injection channels being arranged in an axial center of the stator body, and wherein the injection channels are filled with the potting material.

9. A method for producing an electric motor vehicle traction motor, the traction motor including (i) a motor housing, (ii) a motor stator having a stator body with stator slots and a plurality of stator coils, wherein axial phase windings of the stator coils are arranged in the stator slots, and (iii) an internal motor rotor which is separated fluidically from the motor stator, said method comprising the steps of: injecting liquid potting material into the stator slots radially from an inside of the stator slots and/or radially from an outside of the stator slots in order to form a slot potted body, inserting a motor rotor into the motor stator, and installing the motor rotor and the motor stator into a motor housing.

10. The method as claimed in claim 9, further comprising inserting a mold core with radial injection channels into the motor stator before the injecting step, through which radial injection channels the liquid potting material is injected radially into the stator slots.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0024] In the following text, one exemplary embodiment of the electric motor vehicle traction motor according to aspects of the invention and the production method for producing it will be described in greater detail on the basis of the drawings, in which:

[0025] FIG. 1 shows a diagrammatic longitudinal section of an electric motor vehicle traction motor according to aspects of the invention with a liquid-cooled motor stator and a dry running motor rotor,

[0026] FIG. 1a shows an enlarged illustration of a detail Ia of the fluid-tight attachment of the motor stator and the motor housing,

[0027] FIG. 2 shows a diagrammatic cross section II-II of the traction motor from FIG. 1, and

[0028] FIGS. 3a to 3c show three method steps of a method for producing the motor vehicle traction motor of FIGS. 1, 1a and 2.

DETAILED DESCRIPTION OF THE INVENTION

[0029] FIGS. 1 and 2 diagrammatically show an electric motor vehicle traction motor 10 with a motor housing 12, a liquid-cooled motor stator 30 and a dry running internal motor rotor 20 which is separated fluidically from the motor stator 30. The motor rotor 20 is formed substantially by a rotor shaft 22 and a permanently magnetic rotor body 24 which is seated fixedly on the rotor shaft 22 for conjoint rotation. The rotor shaft 22 rotates about a motor axis 11 which is the central longitudinal axis of the traction motor 10. The motor stator 30 is formed substantially by a stator body 36 which is formed from a multiplicity of identical stator laminations 36′ and by a multiplicity of stator coils 31.

[0030] Each stator core 31 is formed in each case by two axial phase windings 32 which are adjacent to one another and by winding heads 34 which connect the two axial phase windings 32 to one another in each case on the end side. The stator body 36 has a multiplicity of stator slots 37, in which the axial phase windings 32 of the stator coils 31 are arranged. Each axial phase winding 32 consists in each case of a plurality of coil wires which run approximately in the longitudinal direction with respect to one another and parallel to one another, and between which small intermediate spaces exist in each case. All of the coil wires in each case have an electrical insulation layer which is formed by an insulating varnish.

[0031] Each stator slot 37 is delimited substantially by slot walls 42, 43 which form a constant cross-sectional profile in the longitudinal direction, each stator slot 37 being open toward the motor rotor 20 radially on the inside in each case via a longitudinal slit-like slot opening 66. The slot openings 66 in each case separate the pole shoes of the stator body 36 from one another.

[0032] The motor stator 30 has a slot potted body 40 consisting of a potting material 40′ which is an epoxy resin in the present case. The axial phase windings 32 or the coil wires which form them are potted in a fluid-tight manner in the slot potted body 40, with the result that the slot potted body 40 or the potting material 40′ fills both the intermediate space between the respective axial phase winding 32 and the respective slot walls 42, 43 and the intermediate spaces between the coil wires among one another. The slot openings 66 are also filled in each case with the potting material 40′ of the potted body 40 and are closed fluidically in this way.

[0033] The cylindrical inner circumferential face 38 of the stator body 36 on one side and the cylindrical outer circumferential face 25 of the rotor body 24 on the other side define a cylindrical ring-shaped air gap 50 between them, which air gap 50 separates the motor stator 30 and the motor rotor 20 from one another or by which air gap 50 the motor stator 30 and the motor rotor 20 are spaced apart from one another radially.

[0034] The stator body 36 has a plurality of axial cooling ducts 60, by way of which the two annular cooling spaces 14, 14′ are connected fluidically to one another. Furthermore, the stator body 36 has a plurality of radial injection channels 62, each injection channel 62 in each case connecting a stator slot 37 to the radial outer side of the stator body 36. The injection channels 62 are arranged in the axial center of the stator body 36, and are filled completely with the potting material 40′.

[0035] The winding heads 34 of the stator coils 31 are of potting-free configuration, and in each case protrude axially into a fluid-tight annular cooling space 14, 14′. The slot potted body 40 protrudes axially with an axial overhang 70 in each case out of the stator slots 37 and into the respective cooling space 14, 14′. The axial overhang 70 is at least several millimeters.

[0036] The motor housing 12 has a substantially cylindrical inner cooling space wall 13, on the cylindrical outer circumferential face 13′ of which an annular slit-like seal groove 17 is made, in which a sealing ring 16 is inserted, on which the inner circumferential face 38 of the motor stator 30 lies in a fluid-tight manner radially from the outside.

[0037] FIGS. 3a to 3c show three phases of a method for producing the electric motor vehicle traction motor 10. First of all, an unfinished motor stator 30′ is produced which consists of the stator body 36 and the stator coils 31 which are inserted into it, as shown in FIG. 3a. Subsequently, a fully cylindrical mold core 100 with a central axial supply channel 102 and a plurality of injection channels 103 which emanate radially from it is inserted into the cylindrical cavity of the unfinished motor stator 30′, as shown in FIG. 3b. Each injection channel 103 is aligned with a stator slot 37, with the result that the number of injection channels 103 corresponds to the number of stator slots 37. The external diameter of the cylindrical mold core 100 is merely slightly smaller than the internal diameter of the cylindrical inner circumferential wall 38 of the stator body 36.

[0038] Subsequently, the liquid potting material 40′ is injected through the radial injection channels 103 radially from the inside and through mold injection channels 63 and the stator body injection channels 62 which are aligned radially with them radially from the outside into the axial center of the stator slots 37, with the result that the liquid potting material 40′ propagates in the stator slots 37 from the axial center in the two axial directions in the direction of the two cooling spaces 14, 14′. In this way, all the cavities within the stator slots 37 are filled with a potted body 40″ consisting of the liquid potting material 40′. The potting process is stopped as soon as the potting material 40′ has formed a sufficient overhang 70 in the two cooling spaces 14, 14′.

[0039] All the potting molds including the mold core 100 are finally removed, with the result that the motor stator 30 is finished after hardening of the slot potted body 40. The motor stator 30 is finally installed into the motor housing 12, and the motor rotor 20 is installed into the motor stator 30.