WO2025103676A1

WO2025103676A1 - Electrical machine, electrical system and mobility device comprising such an electrical machine

Info

Publication number: WO2025103676A1
Application number: PCT/EP2024/078848
Authority: WO
Inventors: Rameshkumar GOPALAKRISHNAN; Shofiya-Shalini DURAISAMY; Nico Wolf
Original assignee: Valeo Eautomotive Germany Gmbh
Priority date: 2023-11-16
Filing date: 2024-10-14
Publication date: 2025-05-22
Also published as: DE102023131961A1

Abstract

The electrical machine comprises: - a stator (102) comprising a stator core (104) extending around a central axis, and a winding arrangement (204); and - a connector (502) connected to the winding arrangement (204), the connector (502) comprising a terminal (512) configured to be connected to an external electrical conductor The connector (502) further comprises at least one solid connection wire (504) connecting the winding arrangement (204) to the terminal (512), the solid connection wire (504) having a central portion (506) with a round or oval cross-section and an end (508) with a longitudinal plane face fixed, for example welded, against a plane face of the winding arrangement (204).

Description

Electrical machine, electrical system and mobility device comprising such an electrical machine

The present invention relates to an electrical machine, an electrical system and a mobility device comprising such an electrical machine. A mobility device is for example a land motor vehicle, a train, an aircraft or even a drone. A motorized land vehicle is, for example, a motor vehicle, a motorcycle, a motorized bicycle or even a motorized wheelchair.

Background of the invention

It is known from the prior art to use an electrical machine comprising: a stator comprising: a stator core extending around a central axis, and a winding arrangement; and a connector connected to the winding arrangement, the connector comprising a terminal configured to be connected to an external electrical conductor.

For example, in patent application US 2012 0187783 A1 , the winding arrangement comprises several winding wires, the electrical machine further comprising connection members for connecting ends of the winding wires.

The connector further comprises a flexible cable, usually braided or stranded, coupled, at one end, to one of the connection members and, at the other end, to the terminal.

This known connector therefore requires to connect the flexible cable to the connection member, which does not provide a good electrical connection. Furthermore, this known connector is not very convenient for mass production, as the flexible cable, because it is flexible, have to be maintained, usually manually, in the place where it needs to be connected, in particular against the connection member.

In patent application DE 1020 181 18279 A1 , the electrical machine further comprises sleeves connected to ends of the winding wires of the winding arrangement. The connector further comprises a flattened busbar with a rectangular cross-section inserted, at one end, to one of the sleeves and coupled, at the other end, to the terminal. Because of its rectangular cross-section, the busbar comprises four flat longitudinal faces, according to which the busbar can be bent. However, it cannot be bent in other directions, which limits the shape of the busbar. In particular, it may be difficult to use such a busbar in a cluttered environment.

It may thus be desirable to provide an object which makes it possible to overcome at least some of the aforementioned problems and constraints.

Summary of the invention

It is proposed an electrical machine comprising: a stator comprising : a stator core extending around a central axis, and a winding arrangement ; and a connector connected to the winding arrangement, the connector comprising a terminal configured to be connected to an external electrical conductor; characterized in that the connector further comprises at least one solid connection wire connecting the winding arrangement to the terminal, the solid connection wire having a central portion with a round or oval cross-section and an end portion extending along the connection wire from the central portion, the end portion having a crosssection with at least one straight side forming a longitudinal plane face on the end portion.

On one hand, thanks to the round or oval cross-section of the central portion, the solid connection wire can easily be bent in nearly all directions to achieve a complicated shape, thus fitting complicated specifications. On the other hand, thanks to the plane face, a high contact surface between the solid connection wire and the winding arrangement and/or the terminal, having also a plane face, can be achieved.

The invention may also include one or more of the following optional features, in any technically possible combination.

Optionally, the cross-section of the end portion of the solid connection wire has a D- Shape.

Also optionally, the cross-section of the end portion of the solid connection wire has several straight sides.

Also optionally, the cross-section of the end portion of the solid connection wire has four straight sides, so as to present a rectangular cross-section. In the present invention, a rectangular cross-section means a cross-section including four straight sides, with opposite sides parallel to each other, and adjacent sides perpendicular to each other. Adjacent sides are connected to each other either by a straight angle or, as in the example shown, by rounded corners. Each straight side extends on at least 40% of the dimension of the cross-section along the straight side. Each straight side of the cross-section thus forms a longitudinal plane face on the end portion. A rectangular cross-section can be a square cross-section.

Also optionally, the cross-section of the end portion of the solid connection wire has rounded corners.

Also optionally, the central portion of the solid connection wire is bent at several locations around non-parallel axes. For example, the central portion comprises at least between two and five bends.

Also optionally, the end portion is fixed, for example welded, to a plane face of the winding arrangement by the longitudinal plane face.

Also optionally, the winding arrangement comprises a winding wire having a rectangular cross-section to form the plane face of the winding arrangement.

Also optionally, the electrical machine comprises another solid connection wire fixed, for example welded, to another winding wire of the winding arrangement.

Also optionally, the solid connection wire has another end portion extending along the connection wire from the central portion, the other end portion having a cross-section with at least one straight side forming another longitudinal plane face on the end portion, and the other end portion is fixed, for example welded, to a connection portion of the terminal, by the other longitudinal plane face.

Also optionally, the connection portion of the terminal is provided with a connection hole for connecting the terminal to the external electrical conductor.

It is also proposed an electrical system comprising an electrical machine according to the invention, and an inverter connected to the connector.

It is also proposed a mobility device comprising an electrical machine according to the invention. Brief description of the drawings

The invention will be better understood using the following description, given solely by way of example and made with reference to the accompanying drawings in which:

[figure 1] is an axial cross-section view of an electrical machine according to the invention,

[figure 2] is a transverse cross-section view of the electrical machine,

[figure 3] is a three dimensional view of a winding arrangement of the electrical machine,

[figure 4] is a plan view of a winding wire of the winding arrangement,

[figure 5] is a three dimensional view of the winding arrangement with a connector for connecting an inverter to the electrical machine,

[figure 6] is a three dimensional view of a part of the connector,

[figure 7] is a three dimensional view of a connection wire of the connector before flattening of its ends,

[figure 8] is a three dimensional view of the connection wire, with both ends flattened, and

[figure 9] is a three dimensional view of an alternative winding wire of the winding arrangement.

Detailed description of the invention

Referring to figure 1 , an electrical machine 100 according to the invention will now be described.

The electrical machine 100 comprises a stator 102 having a stator core 104 extending around a central axis 106. The stator core 104 has an inner face 108. The stator core 104 is comprised of a ferromagnetic material and is typically formed from a plurality of steel sheets 109 that are stamped and stacked upon one another to form a lamination stack.

The electrical machine 100 further comprises a rotor 110 extending inside the stator core 104. The rotor 110 is configured to rotate around the central axis 106. Referring to figure 2, the inner face 108 of the stator core 104 is provided with longitudinal slots 202. The stator 102 further comprises a winding arrangement 204 extending into the longitudinal slots 202. The winding arrangement 204 defines several phases, for example three phases.

Referring to figure 3, the winding arrangement 204 comprises several winding wires 302 connected to other to form the winding arrangement 204. Each winding wire 302 is for example solid (i.e. not braided nor stranded) and has a rectangular cross-section, for example with rounded corners.

Referring to figure 4, each winding wire 302 has for example a general U shape with two legs 402, 404 connected by a turn portion 406. For example, the winding wire 302 is formed from a straight copper conductor segment with a rectangular cross-section, for example with rounded corners, which is bent in order to create the turn portion 406. The two legs 402, 404 are then inserted in two respective longitudinal slots 202, such that two end portions 408, 410 of the legs 402, 404, respectively, extend out of the longitudinal slots 202. The end portions 408, 410 of the legs 402, 404 are then bent to be fixed to the end portions of other winding wires 302.

Referring to figure 5, the electrical machine 100 further comprises, for each phase, a connector 502, the connectors 502 being configured to be connected for example to an inverter, according to a Wye or Delta connection. The connector 502 first comprises at least one solid connection wire 504 (two in the illustrated example, it could be three) having a central portion 506 with a round or oval cross-section and two end portions 508, 510 which are flattened in the illustrated example so as to exhibit a rectangular cross-section, with opposite sides parallel to each other, and adjacent sides perpendicular to each other. Each straight side of the cross-section thus forms a longitudinal plane face on the flattened end portion 508, 510. In the illustrated example, each end portion 508, 510 thus comprises four longitudinal plane faces.

The solid connection wire 504 is for example a magnet wire, i.e. a enamel-insulated wire, or a non-insulated wire.

The connector 502 further comprises a terminal 512. The terminal 512 has at least one fixing portion 514 (two in the illustrated example, it could be three) to which the second flattened end 510 of the solid connection wire 504 is fixed. When several solid connection wires 504 and several fixing portions 514 are provided, the second flattened ends 510 of the solid connection wires are respectively fixed to the fixing portions 514. For example, as in the illustrated example, the terminal 512 comprises a flat sheet with two bent opposite side portions. The flat sheet thus comprises a flat central portion, having for example an overall rectangular shape, namely the shape of a rectangular cuboid. At the bends between the central portion and the bent portions, notches may be provided to allow easier bending.

The terminal 512 further comprises a connection portion 516 configured to be connected to an external electrical conductor, in particular to be connected to an inverter, either directly or through an intermediate connector. For example, the connection portion 516 is provided with a connection hole 518, for example a through-hole. The connection hole 518 is for example provided with a thread, so that the other electrical conductor can be fixed to the connection portion 516 by a screw. Alternatively, the other electrical conductor could be fixed to the connection portion 516 by clipping fit or snap fit.

Although illustrated naked, the connector 502 may be overmolded with plastic.

Referring to figure 6, each fixing portions 514 of the terminal 512 includes a plane face 602 against which a plane face defined by the flattened end 510 of the respective connection wire is fixed, for example welded.

Referring to figure 7, the solid connection wire 504 can be bent to have a complicated shape. In particular, it can be bent at several locations around several non-parallel axes 702.

Referring to figure 8, the two ends 508, 510 of the solid connection 504 wire can then be flattened, that that to provide them with respective longitudinal plane faces 802, 804.

The invention is not limited to U-shaped winding wire. For example, referring to figure 9, each winding wire 302 has for example a general I shape with two ends 902, 904. For example, the winding wire 302 is formed from a straight copper conductor segment with a rectangular cross-section, for example with rounded corners, which is bent in order to create the general shape of the winding wire 302. The winding wire 302 is then inserted in one of the longitudinal slots 202, such that its two ends 902, 904 extend out of the longitudinal slots 202, on both sides of the longitudinal slots 202. The ends 902, 904 of the winding wire 302 are then bent to be fixed to the ends 902, 904 of other winding wires 302, or, for at least one of the winding wires 302, to the connector 502. In conclusion, it is clear that an electrical machine such as the one described above allows great flexibility in the connection of the electrical machine.

It will also be noted that the invention is not limited to the embodiment described above. It will indeed appear to those skilled in the art that various modifications can be made to the embodiment described above, in the light of the teaching which has just been disclosed to them.

In the detailed presentation of the invention which is made above, the terms used must not be interpreted as limiting the invention to the embodiment set out in the present description, but must be interpreted to include therein all the equivalents includ- ing the prediction is within the reach of those skilled in the art by applying their general knowledge to the implementation of the teaching which has just been disclosed to them.

Claims

1 . Electrical machine (100) comprising : a stator (102) comprising :

- a stator core (104) extending around a central axis (106), and

- a winding arrangement (204) ; and

- a connector (502) connected to the winding arrangement (204), the connector (502) comprising a terminal (512) configured to be connected to an external electrical conductor ; characterized in that the connector (502) further comprises at least one solid connection wire (504) connecting the winding arrangement (204) to the terminal (512), the solid connection wire (504) having a central portion (506) with a round or oval cross-section and an end portion (508, 510) extending along the connection wire (504) from the central portion (506), the end portion (508, 510) having a cross-section with at least one straight side forming a longitudinal plane face (802, 804) on the end portion (508, 510).

2. Electrical machine (100) according to claim 1 or 2, wherein the cross-section of the end portion (508, 510) of the solid connection wire (504) has several straight sides, for example being rectangular.

3. Electrical machine (100) according to any of claims 1 to 3, wherein the central portion (506) of the solid connection wire (504) is bent at several locations around non-parallel axes (702).

4. Electrical machine (100) according to any of claims 1 to 3, wherein the end portion (508) is fixed, for example welded, to a plane face of the winding arrangement (204) by the longitudinal plane face (802).

5. Electrical machine (100) according to claim 4, wherein the winding arrangement (204) comprises a winding wire (302) having a rectangular cross-section to form the plane face of the winding arrangement (204).

6. Electrical machine (100) according to claim 5, comprising another solid connection wire (504) fixed, for example welded, to another winding wire

7. Electrical machine (100) according to any of claims 1 to 6, wherein the solid connection wire (504) has another end portion (510) extending along the connection wire (504) from the central portion (506), the other end portion (510) having a cross-section with at least one straight side forming an- other longitudinal plane face (804) on the end portion (510), and wherein the other end portion (510) is fixed, for example welded, to a connection portion (516) of the terminal (512), by the other longitudinal plane face (804).

8. Electrical machine (100) according to claim 7, wherein the connection por- tion (516) of the terminal (512) is provided with a connection hole (518) for connecting the terminal (512) to the external electrical conductor.

9. Electrical system comprising an electrical machine according to any of claims 1 to 8, and an inverter connected to the connector (502).

10. Mobility device comprising an electrical machine (100) according to any of claims 1 to 9.