Patent Application
20240072593
The present disclosure relates to a stator for an electric machine, in particular for use in a hybrid or fully electric drive train of a motor vehicle, wherein the stator has a cylindrical opening which extends axially through the stator and on which a plurality of stator slots are present, said stator slots being arranged in a peripherally distributed manner and extending radially outward from an inner cylinder jacket surface of the cylindrical opening and being formed over the entire axial length of the stator, wherein the stator slots each have a slot base on the radially outer end thereof and an air gap to a rotor, which can be received in the cylindrical opening, on the radially inner end thereof, wherein stator windings having winding wires are arranged in the stator slots and the stator windings are designed as a wave winding having a first winding mat and a second winding mat.
Electric motors are increasingly being used to drive motor vehicles in order to create alternatives to internal combustion engines that require fossil fuels. Significant efforts have already been made to improve the suitability of electric drives for everyday use and also to be able to offer users the driving comfort they are accustomed to.
However, there is still an ongoing need to further optimize such electric motors for the mass market, in particular in terms of production costs. A major cost factor in the production of these electric motors is the winding and interconnection of the stator windings.
Stators for electric machines with a wave winding are also known from the prior art for use in drive trains of motor vehicles. In such a wave winding, the individual winding wires are not routed in a circular manner between two stator slots, but loop successively through all the stator slots of a stator according to a wave form. This allows automated production equipment to be used, enabling suitably wound stators to be produced more efficiently and economically.
If a winding configuration with two or more winding mats is required for these generic stators, the respective winding ends of the winding mats usually abut the stator circumferentially offset by 180°. This large circumferential distance of the winding ends leads to an increased interconnection effort as well as a more complex and expensive production, since the interconnection usually has to be realized by means of one or more additional interconnection rings. Although this reduces the complexity of the production process by means of a predefined positioning in it for each winding end, the additional production effort and the associated costs for this additive component are disadvantageous. As an alternative to the use of an interconnection ring, the winding ends can also be interconnected directly, but this involves a significant increase in complexity and cost in the production of such stators.
DE102008007409A1 describes, for example, a three-part switching ring for a stator, wherein three busbars and a star point ring are arranged in one plane, lying flat next to one another in a carrier ring made of a temperature-resistant plastic. The contact points of the busbars and the star point ring project from the carrier ring and are connected to the wire ends of the partial windings of the stator.
The object of the present i disclosure is now to provide a stator which at least mitigates or completely eliminates the described disadvantages of the prior art and in which an interconnection of a stator winding with at least two winding mats can be realized in a simple and cost-optimized manner without the use of interconnection rings.
This object is achieved by a stator for an electric machine, in particular for use in a hybrid or fully electric drive train of a motor vehicle, wherein the stator has a cylindrical opening which extends axially through the stator and on which a plurality of stator slots are present, said stator slots being arranged in a peripherally distributed manner and extending radially outward from an inner cylinder jacket surface of the cylindrical opening and being formed over the entire axial length of the stator, wherein the stator slots each have a slot base on the radially outer end thereof and an air gap to a rotor, which can be received in the cylindrical opening, on the radially inner end thereof, wherein stator windings having winding wires are arranged in the stator slots and the stator windings are designed as a wave winding having a first winding mat and a second winding mat, wherein the first winding mat has a group of first winding wires, the winding ends of which are each arranged above the same stator slot in each case, and the winding ends of the first group of winding wires each have a first winding end and a second winding end, wherein the first winding end of the first group of winding wires abuts facing the slot base and the second winding end of the first group of winding wires abuts facing the air gap of this stator slot and the second winding mat has a group of second winding wires, the winding ends of which are each arranged above the same stator slot in each case, and the winding ends of the second group of winding wires each have a first winding end and a second winding end, wherein the first winding end of the second group of winding wires abuts facing the slot base and the second winding end of the second group of winding wires abuts facing the air gap of this stator slot.
The advantage of the stator according to the disclosure is thus that an additional interconnection ring can be dispensed with, since no interconnection of winding wire ends in the circumferential direction from one side of the stator to the opposite side is required in order to interconnect the winding wire ends. The stator according to the disclosure allows interconnections only within two poles, which reduces the production effort and cost of the stator winding interconnection.
First, the individual elements of the claimed subject matter of the disclosure are explained in the order in which they are named in the claims and particularly preferred embodiments of the subject matter according to the disclosure are described below.
The stator according to the disclosure is configured in particular for use within an electric machine designed as a radial flux machine.
Electric machines are used to convert electrical energy into mechanical energy and/or vice versa, and generally comprise a stationary part referred to as a stator, stand or armature, and a part referred to as a rotor or runner and arranged movably relative to the stationary part.
The electric machine is intended in particular for use within a drive train of a hybrid or fully electric motor vehicle. In particular, the electric machine is dimensioned such that vehicle speeds of more than 50 km/h, preferably more than 80 km/h and in particular more than 100 km/h can be achieved. The electric motor particularly preferably has an output of more than 30 kW, preferably more than 50 kW and in particular more than 70 kW. Furthermore, it is preferred that the electric machine provides speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, very particularly preferably greater than 12,500 rpm.
The stator has a cylindrical structure and preferably consists of electrical laminations that are electrically insulated from one another, constructed in layers and packaged to form laminated cores. With this structure, the eddy currents in the stator caused by the stator field are kept low. Distributed around the circumference, stator slots are embedded into the electrical lamination running parallel to the rotor shaft, which receive the stator winding or parts of the stator winding. Depending on the construction towards the surface, the stator slots can be closed with closing elements, such as closing wedges or covers or the like, to prevent the stator winding from detaching.
Stator teeth are components of the stator which are designed as circumferentially spaced, tooth-like parts of the stator directed radially inward or radially outward and between whose free ends and a rotor body an air gap for the magnetic field is formed.
A stator winding is an electrically conductive conductor whose length extension is much greater than its diameter. The stator winding can generally have any cross-sectional shape. Rectangular cross-sectional shapes are preferred, as these allow for high packing densities and consequently high power densities to be achieved. Particularly preferably, a stator winding is formed of copper. Preferably, a stator winding has an insulation.
In particular, the stator can be provided for use in an electric machine within a drive train of a motor vehicle. In the context of this application, the drive train of a motor vehicle is understood to mean all components that generate the power for driving the motor vehicle in the motor vehicle and transmit it to the road via the vehicle wheels.
The stator can also preferably be provided for use in an electric machine within a hybrid module for a motor vehicle. In a hybrid module, structural and functional elements of a hybridized drive train can be spatially and/or structurally combined and preconfigured so that a hybrid module can be integrated into a drive train of a motor vehicle in a particularly simple manner. In particular, an electric machine and a clutch system, in particular with a separating clutch for engaging the electric machine in and/or disengaging the electric machine from the drive train, can be present in a hybrid module.
In particular, the stator can also preferably be provided for use in an electric axle drive train within a drive train of a motor vehicle. An electric axle drive train of a motor vehicle comprises an electric machine and a transmission, wherein the electric machine and the transmission form a structural unit. This structural unit is sometimes also referred to as an E-axle.
According to an advantageous embodiment, the winding ends of the first group of winding wires and the winding ends of the second group of winding wires can be arranged opposite each other in the circumferential direction in the stator slots of the stator.
In accordance with a further preferred further development of the disclosure, the first winding mat and the second winding mat can be formed substantially identically, whereby the production costs of the stator can be further optimized by reducing the complexity of the components used.
Furthermore, according to a likewise advantageous embodiment, the winding ends of the first group of winding wires can be arranged in circumferentially adjacent stator slots and/or the winding ends of the second group of winding wires can be arranged in circumferentially adjacent stator slots, which further reduces the interconnection effort due to the corresponding spatial proximity of the winding ends to be interconnected.
According to a further particularly preferred embodiment, the stator windings can be designed for use, in particular, in a 3-phase rotating field machine.
Furthermore, the disclosure can also be further developed in that the interconnection of the first group of winding wires of the first winding mat and the second group of winding wires of the second winding mat is identical, thereby realizing a reduction in complexity and cost by using identical components. Furthermore, the use of identical winding mats allows for a simplified installation of the winding mats.
In a likewise preferred embodiment, the stator windings can have a number n of more than two winding mats, and the winding mats can be arranged circumferentially offset from one another by n/360° in the stator slots of the stator. This allows for a simple design adjustment of the electric machine, for example by adjusting the number of parallel branches and/or the number of winding mats. Furthermore, a reduction in complexity can be achieved by using the same interconnection for different designs in the production and assembly of an electric machine wound in this manner.
The disclosure will be explained in more detail below with reference to figures without limiting the general concept according to the disclosure.
In the figures:
The stator slots 7 each have a slot base 14 on the radially outer end thereof and an air gap 15 to a rotor 16, which can be received in the cylindrical opening 5, on the radially inner end thereof. The stator windings 8 are arranged with winding wires 9 in the stator slots 7.
The stator windings 8 are formed as a wave winding with a first winding mat 10 and a second winding mat 11, wherein the first winding mat 10 and the second winding mat 19 are formed substantially identically.
Referring to
Similarly, the second winding mat 19 has a group of second winding wires 20, the winding ends 21 of which are each arranged above the same stator slot 7 in each case, and the winding ends 21 of the second group of winding wires 20 each have a first winding end 22 and a second winding end 23. The first winding end 22 of the second group of winding wires 20 is positioned facing the slot base 14, and the second winding end 23 of the second group of winding wires 20 is positioned facing the air gap 15 of this stator slot 7.
In principle, it is possible for the winding ends 22,23 to exit the stator slots 7 of the stator 1 at a common winding head end or at different winding head ends.
In the exemplary embodiment shown in
The upper interconnection diagram, designated with “a”, shows the interconnection on the first end face of the stator 1, and the lower interconnection diagram, designated with “b”, shows the interconnection on the second end face of the stator 1.
In the exemplary embodiment shown in
The winding wires 12,20 of a winding mat 10,19 extend in the radial direction starting at one of the end faces of the stator 1 near the yoke of a slot 7 in order to extend through it in the axial direction and exit the corresponding slot 7 on the opposite end face of the stator.
Irrespective of the interconnection design, the number of windings depends, in this regard, on the number of slots 7 and the number of winding wires 12,20 per slot 7. This means that both a motor with 36, 54, 72 or 90 slots 7 and with 4, 6, 8, etc. conductors per slot can be interconnected in the same way.
This can also be seen well in the identical designations of the windings in the sequence A1,A2,A1,B2,B1,B2,C1,C2,C1,A2,A1,A2,B1,B2,B1,C2,C1,C2 in the stator slots 7 with the numbers 1-18 on the first end face “a” and the second end face “b” of the stator 1 for the first winding mat 10 and the identical designations of the windings in the sequence A3,A4,A3,B4,B3,B4,C3,C4,C3,A4,A3,A4,B3,B4,B3,C4,C3,C4 in the stator slots 7 with the numbers 19-36 on the first end face “a” and the second end face “b” of the stator 1 for the second winding mat 19.
The interconnection of the first winding mat 10 in the exemplary embodiment shown in
The interconnection of the first winding mat 10 in the exemplary embodiment shown in
The interconnection of the second winding mat 19 in the exemplary embodiment shown in
The interconnection of the second winding mat 19 in the exemplary embodiment shown in
It can be readily seen from
Furthermore, it can be seen from
In particular, the stator 1 is intended for use in a hybrid or fully electric drive train 3 of a motor vehicle 4, as exemplarily shown in
The disclosure is not limited to the embodiments shown in the figures. The above description is therefore not to be regarded as limiting, but rather as illustrative. The following claims are to be understood as meaning that a named feature is present in at least one embodiment according to the disclosure. This does not exclude the presence of further features. If the patent claims and the above description define ‘first’ and ‘second’ features, this designation serves to distinguish between two features of the same type without defining an order of precedence.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 105 323.4 | Mar 2021 | DE | national |
This application is the U.S. National Phase of PCT Appln. No. PCT/DE2022/100107, filed Feb. 8, 2022, which claims priority from German Patent Application No. 10 2021 105 323.4, filed Mar. 5, 2021, the entire disclosures of which are incorporated by reference herein.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/DE2022/100107 | 2/8/2022 | WO |
