CN-114915072-B - Stator

Abstract

A stator (10) for an electric machine provided for purely electrically driving a motor vehicle is proposed, having a stator body (12) forming a stator slot (14), a stator winding (18) which is engaged in the stator slot (14) and protrudes axially therefrom and through which an electric current can flow for forming an electromagnetic rotating field, an insulating paper (20) provided in the stator slot (14) between the stator winding (18) and the stator body (12) for electrically insulating the stator winding (18) relative to the stator body (12), wherein the insulating paper (20) protrudes from the stator slot (14), the insulating paper (20) being provided on its surface with an additional layer (26) for providing a higher leakage strength than the surface of the insulating paper (20) without the additional layer (26). The axial extension of the insulating paper (20) and the stator (10) can be reduced by the additional layer (26) realizing higher leakage strength, thereby realizing an electric machine which saves structural space and is safe and reliable.

Inventors

• T. Hubert
• S. SCHMIDT
• J. SCHNEIDER

Assignees

• 保时捷股份公司

Dates

Publication Date

20260505

Application Date

20220210

Priority Date

20210210

Claims (12)

1. 1. A stator for an electric machine configured for purely electrically driving a motor vehicle, the stator having: a stator main body (12) forming a stator slot (14); A stator winding (18) which is engaged into the corresponding stator slot (14) and axially protrudes from the stator slot (14) and through which a current can flow, the stator winding being used for forming an electromagnetic rotating field, and An insulating paper (20) arranged in the stator slot (14) between the stator winding (18) and the stator body (12), the insulating paper being used for electrically insulating the stator winding (18) with respect to the stator body (12), wherein the insulating paper (20) protrudes from the stator slot (14), It is characterized in that the method comprises the steps of, The insulating paper (20) is provided with an additional layer (26) on its surface for providing a higher leakage strength than the surface of the insulating paper (20) without the additional layer (26), wherein, The additional layer (26) is arranged only outside the stator slot (14) and is arranged in a play-free manner with respect to the stator slot, so that the axial extension of the portion of the insulating paper (20) arranged outside the stator slot (14) is reduced, wherein, The additional layer (26) is arranged only on the outer side (22) of the insulating paper (20) facing away from the stator winding (18) and on the end side (24) facing away from the stator body (12).
2. 2. A stator according to claim 1, characterized in that the insulating paper (20) has a higher leakage strength outside the stator slot (14) than inside the stator slot (14) due to the additional layer (26).
3. 3. Stator according to claim 1 or 2, characterized in that the additional layer (26) at least belongs to insulating material group IIIa or insulating material group II according to IEC 60112 with use of a solution.
4. 4. Stator according to claim 1 or 2, characterized in that the additional layer (26) has a CTI value of > 175 in accordance with IEC 60112 in case a solution is used.
5. 5. Stator according to claim 1 or 2, characterized in that the surface of the insulating paper (20) without the additional layer (26) belongs to insulating material group II or insulating material group IIIa according to IEC 60112 with use of a solution.
6. 6. Stator according to claim 1 or 2, characterized in that the additional layer (26) is made of plastic and/or resin.
7. 7. Stator according to claim 1 or 2, characterized in that the insulating paper (20) is attached against the stator winding (18) and/or glued to the stator winding (18).
8. 8. Stator according to claim 1 or 2, characterized in that the insulating paper (20) is pressed against the stator body.
9. 9. The stator according to claim 4, characterized in that the additional layer (26) has a CTI value of 175-800 according to IEC 60112 in case a solution is used.
10. 10. The stator according to claim 4, characterized in that the additional layer (26) has a CTI value of 400-CTI < 600 in accordance with IEC 60112 in case a solution is used.
11. 11. Stator according to claim 6, characterized in that the plastic is PE and/or PTFE and/or PBT.
12. 12. The stator according to claim 6, characterized in that the resin is an epoxy resin and/or a polyester resin.

Description

Stator Technical Field The invention relates to a stator by means of which an electric machine provided for driving a motor vehicle purely electrically can be combined. Background A stator slot for a stator of an electric machine is known from DE 10 2017 214 195 A1, which is lined with insulating paper in order to electrically insulate windings introduced into the stator slot, wherein the insulating paper protrudes from the stator slot in the axial direction. There is always a need to reduce the structural space of electric machines without compromising electrical safety. Disclosure of Invention The object of the invention is to demonstrate measures which make it possible to achieve an electric machine which is space-saving and safe. According to the invention, this object is achieved by a stator according to the invention. In the preferred embodiments and in the following description, preferred embodiments of the invention are given, which may form an aspect of the invention, both individually and in combination. Aspects of the present invention relate to a stator for an electric machine provided for purely electrically driving a motor vehicle, the stator having a stator body forming stator slots, a stator winding coupled into and axially protruding from the respective stator slots, through which an electric current can flow, for forming an electromagnetic rotating field, and an insulating paper provided in the stator slots between the stator winding and the stator body, for electrically insulating the stator winding with respect to the stator body, wherein the insulating paper protrudes from the stator slots, wherein the insulating paper is provided with an additional layer on a surface thereof, for providing a higher leakage strength (Kriechstromfestigkeit) than a surface of the insulating paper without the additional layer. In particular, the stator body designed as a sheet can have teeth, preferably rib-shaped, which protrude in the radial direction, between which teeth corresponding stator grooves are formed. If the stator is provided for an electric machine designed as an inner rotor, the teeth protrude radially inwards, while the stator slots can open radially inwards. If the stator is provided for an electric machine designed as an outer rotor, the teeth protrude radially outwards, while the stator slots can open radially outwards. The stator winding, which is composed of electrical conductors, in particular enamelled wires, can be guided in the axial direction through the respective stator slot, wherein the stator winding can be guided axially out of the respective stator slot on one axial side or on both axial sides. The dielectric strength (Durchschlagfestigkeit) provided by the insulating paper disposed in the stator slots is sufficient to prevent voltage breakdown between the stator windings and the stator body under the electrical boundary conditions to be expected. In electric machines provided for purely electrically driving motor vehicles, the insulating paper usually protrudes slightly in the axial direction together with the stator windings from the respective stator slots. This makes it possible to design the insulating paper taking into account not only its dielectric strength but also its axial extension outside the stator slot, in order to avoid leakage currents. It has been recognized that, especially in the case of purely electrically driven motor vehicles, a significantly higher power density can lead to higher currents and/or voltages in the electric machine, which can make the design of the axial extension of the insulating paper outside the stator slot a design factor determining the axial installation space. By means of this additional layer, the resistance against leakage currents on the surface of the insulating paper formed by the additional layer can be significantly higher than on the surface of the insulating paper where no additional layer is provided. By means of this additional layer, the material properties of the insulating paper in terms of leakage strength can be improved, whereby the axial extension of the insulating paper outside the stator slot can be correspondingly reduced and/or the safety against leakage currents can be increased with the same dimensions. The axial installation space requirement of the stator and the material use required for the stator winding can likewise be reduced by reducing the axial extension of the slot paper. This can reduce production costs. By realizing an additional layer of higher leakage strength, the axial extension of the insulating paper and the stator can be reduced, so that an electric machine which saves structural space and is safe and reliable can be realized. In particular, the dielectric paper has a higher leakage strength outside the stator slot than inside the stator slot due to the additional layer. In principle, it is possible to provide an additional layer on the outside of the insulating paper facing the stator