DE102022121650A1 - Stator and method for producing a stator - Google Patents

Abstract

The invention relates to a stator (1) for an electrical machine (2), wherein the stator (1) is designed in the shape of a cylindrical ring and has a plurality of stator teeth (3), each of which is located in the radial direction in the circumferential direction between adjacent stator teeth (3). Define a stator groove (4) which extends and runs in the axial direction through the stator (1), into which a current-capable stator winding (5) comprising a plurality of electrical conductors (6) is inserted, which is located on a first end face (7) of the stator (1 ) emerge from the stator (1) to form a first winding head (8), a high-voltage terminal (9) adjoining the winding head (8) in the axial direction for connecting the stator winding (5) to a current supply and the high-voltage terminal (9). Winding head (8) is covered at least in sections, a temperature sensor (10) being attached to a side of the high-voltage terminal (9) facing the winding head (8), which rests on one of the electrical conductors (6) of the winding head (8).

Description

The present invention relates to a stator for an electrical machine, wherein the stator is cylindrical ring-shaped and has a plurality of stator teeth, which in the circumferential direction between adjacent stator teeth each define a stator groove which extends in the radial direction and runs through the stator in the axial direction, in which an energized stator winding comprising a plurality of electrical conductors is inserted, which emerge from the stator on a first end face of the stator to form a first winding head, with a high-voltage terminal adjoining the winding head in the axial direction for connecting the stator winding to a current supply and the high-voltage terminal Winding head covered at least in sections. The invention further relates to a method for producing a stator.

Electric motors are increasingly being used to drive motor vehicles in order to create alternatives to combustion engines that require fossil fuels. Significant efforts have already been made to improve the suitability of electric drives for everyday use and to offer users the usual driving comfort.

A detailed description of an electric drive can be found in an article in the magazine ATZ 113th year, 05/2011, pages 360-365 by Erik Schneider, Frank Fickl, Bernd Cebulski and Jens Liebold with the title: Highly integrative and flexible electric drive unit for electric Vehicles, which probably represents the closest state of the art. This article describes a drive unit for an axle of a vehicle, which includes an electric motor which is arranged concentrically and coaxially to a bevel gear differential, with a switchable 2-speed planetary gear set being arranged in the power train between the electric motor and the bevel gear differential, which is also is positioned coaxially to the electric motor or the bevel gear differential or spur gear differential. The drive unit is very compact and, thanks to the switchable 2-speed planetary gear set, allows a good compromise between climbing ability, acceleration and energy consumption. Such drive units are also referred to as e-axles or electrically operated drive trains.

Permanent magnet synchronous machines (PSM) are already used in many industrial applications and, as electrification increases, also in the automotive industry. Such a permanently excited synchronous machine usually has a stator to be energized and a permanently excited rotor. The stator includes, among other things, a stator winding, a stator carrier, a connection ring and a terminal for the power electronics.

Electrical machines with distributed winding or wave winding usually have a connection area in which different conductors of the winding are connected to one another. This coupling is also known as a bridge, which is usually responsible for reversing the direction of the current flow. Furthermore, the connection can also contain a so-called star point or star phase. At this point, all conductors and currents of the different phases flow together in a star connection. The electrical machine has a high-voltage terminal as a further component. This component is responsible for supplying power to the electrical machine via the power electronics.

High-voltage terminals with an integrated circuit area are now known from the prior art. For example, this reveals DE 10 2019 111 825 A1 a stator for an electrical machine with such a high-voltage terminal. From the DE 10 2018 119 831 A1 An electrical machine comprising a stator with concentrated windings arranged on stator teeth and comprising at least one temperature sensor for detecting the temperature of a winding is also already known. A stator component is designed as a connection ring, which carries, for example, one or more metal connection conductor rings.

Furthermore, from the US 2019/0372422 A1 a contacting device for electrically connecting the winding wire ends of the stator windings to contact connections of power electronics is known, in which the corresponding conductor ends to be connected are electrically connected to one another by means of a press connection.

Furthermore, due to the ever-increasing power densities in electrical machines, there is a continuing need to provide effective thermal management, which requires an accurate temperature and not a time-delayed temperature measurement, particularly in the thermal hot spot areas. For this purpose, temperature sensors are usually fixed to the winding heads of the stator windings.

Although such components are known from the prior art, there is still a desire to optimize them. Therefore, the object of the present invention is to provide a stator with a high-voltage terminal that is improved compared to the prior art and which, with compact dimensions, requires a high degree of assembly exhibits honesty. It is also the object of the invention to implement an improved method for assembling a stator.

This object is achieved by a stator for an electrical machine, wherein the stator is cylindrical ring-shaped and has a plurality of stator teeth, which in the circumferential direction between adjacent stator teeth each define a stator groove which extends in the radial direction and runs through the stator in the axial direction, in which has an energized stator winding comprising a plurality of electrical conductors inserted, which emerge from the stator on a first end face of the stator to form a first winding head, with a high-voltage terminal adjoining the winding head in the axial direction for connecting the stator winding to a current supply and the high-voltage terminal covers the winding head at least in sections, with a temperature sensor being attached to a side of the high-voltage terminal facing the winding head, which rests on one of the electrical conductors of the winding head.

This has the advantage that a good thermal connection of the temperature sensor can be guaranteed while at the same time being easy to install. Because the temperature sensor is integrated in the high-voltage terminal, this enables the high-voltage terminal and the temperature sensor to be installed together, so that no extra assembly step is required for the sensor. The temperature sensor is attached to the high-voltage terminal so that it is located between the high-voltage terminal and the stator winding. When the high-voltage terminal is installed, the temperature sensor is thermally coupled to the corresponding electrical conductor.

It can preferably be provided that the temperature sensor is pressed axially onto an electrical conductor of the winding head via a spring element. In this context, it is further preferred that the corresponding electrical conductor of the winding head is shaped such that a flat contact surface is defined between the electrical conductor and the temperature sensor. The sensor can preferably have insulation against environmental influences, for example oil.

First, the individual elements of the claimed subject matter of the invention are explained in the order of their relevance or their mention in the claim sentence and particularly preferred embodiments of the subject matter of the invention are described below.

Electrical machines are used to convert electrical energy into mechanical energy and/or vice versa, and generally include a stationary part called a stator, stand or armature and a part called a rotor or rotor and arranged to be movable relative to the stationary part.

In the case of electrical machines designed as rotary machines, a distinction is made in particular between radial flux machines and axial flux machines. A radial flux machine is characterized in that the magnetic field lines in the air gap formed between the rotor and stator extend in the radial direction, while in the case of an axial flux machine the magnetic field lines in the air gap formed between the rotor and stator extend in the axial direction. In connection with the present invention, the electrical machine is particularly preferably configured as a radial flow machine.

The stator of a radial flux machine is usually cylindrical in design and usually consists of electrical sheets that are electrically insulated from one another and built in layers and packaged into laminated cores. Distributed over the circumference, grooves or circumferentially closed recesses are arranged in the electrical sheet and run parallel to the rotor shaft, which accommodate the stator winding or parts of the stator winding. Depending on the construction towards the surface, the grooves can be closed with closure elements, such as closure wedges or covers or the like, in order to prevent the stator winding from being detached.

A stator winding usually comprises a plurality of electrically conductive conductors, the length of which is significantly larger than their diameter. An electrical conductor of a stator winding can basically have any cross-sectional shape. Rectangular cross-sectional shapes are preferred because they allow high packing and therefore high power densities to be achieved. A stator winding is very particularly preferably made of copper. An electrical conductor of a stator winding preferably has insulation. To insulate the electrical conductors of a stator winding, for example, mica paper, which can be reinforced by a glass fabric support for mechanical reasons, can be wound in tape form around one or more electrical conductors of a stator winding, which are impregnated using a hardening resin. In principle, it is also possible to use a curable lacquer layer without mica paper to insulate an electrical conductor of a stator winding.

In an electrical machine with a hairpin or wave winding, the individual windings distributed around the circumference can be connected, for example, via a connection ring or several connection rings. Here, busbars usually made of copper can be arranged on or in a common or separate support ring made of plastic, which is also referred to as a high-voltage terminal. This type of interconnection ring was also occasionally referred to as switching ring or contact bridge. Such interconnection rings are usually placed axially on the winding package.

A high-voltage terminal can accommodate one or more busbars and, in particular, arrange them at a distance from one another and in an electrically insulating manner. As a rule, a high-voltage terminal has a circular ring-shaped or circular ring section-like basic shape with several circular ring/circular ring section-shaped and concentrically arranged receptacles, such as grooves, in which the corresponding busbars are arranged. A high-voltage terminal is preferably made of an electrically non-conductive plastic material. In principle, it is conceivable to design a high-voltage terminal in one or more parts.

A temperature sensor in the sense of this application is an electrical or electronic component that delivers an electrical signal as a measure of a temperature acting on the temperature sensor. A temperature sensor can, for example, be selected from the group of thermocouples, thermistor temperature sensors, thermistor temperature sensors, semiconductor temperature sensors, ferromagnetic temperature sensors, pyroelectric temperature sensors, fiber-optic temperature sensors, and/or pyrometers.

The temperature sensor is particularly preferably configured as a thermistor temperature sensor, which is also referred to as an NTC resistor or NTC thermistor (negative temperature coefficient thermistor).

The temperature sensor can be connected to the high-voltage terminal in a form-fitting and/or force-fitting and/or material-locking manner, in particular in a non-detachable manner. For example, form-fitting means can be provided on the high-voltage terminal, which effect a form-fitting fixation of the temperature sensor on and/or in the high-voltage terminal. In this context, it is particularly preferred to design the positive locking means as a clip connection into which the temperature sensor can be clipped and is held captive. Furthermore, in this context, it is preferred that the positive locking means are formed monolithically with the high-voltage terminal, for example by a plastic injection molding process.

According to an advantageous embodiment of the invention, it can be provided that the high-voltage terminal is made of plastic and the temperature sensor is at least partially, preferably completely, covered by plastic. The advantage of this design is that the temperature sensor is protected from mechanical and/or chemical influences. In principle, however, it would also be conceivable for the temperature sensor to be openly positioned in the high-voltage terminal at least on the side facing the electrical conductor and thus directly contact an electrical conductor of a stator winding.

According to a further preferred development of the invention, it can also be provided that the high-voltage terminal is manufactured using a plastic injection molding process in which the temperature sensor was inserted into a corresponding injection mold before injection molding, which is particularly favorable in terms of production technology.

Further advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically sensible manner and can define further embodiments of the invention. In addition, the features specified in the claims are specified and explained in more detail in the description, with further preferred embodiments of the invention being presented.

According to an advantageous embodiment of the invention, it can be provided that the electrical conductor on which the temperature sensor rests has a contact section which runs essentially parallel to a fastening section of the high-voltage terminal, to which the temperature sensor is fastened to the high-voltage terminal. The advantage of this configuration is that a particularly easy-to-assemble variant of the stator can be provided.

According to a further preferred development of the invention, it can also be provided that the contact section of the electrical conductor and the fastening section of the high-voltage terminal are essentially flat. This allows a particularly good thermal connection to be achieved. To maximize the contact area between the temperature sensor and the corresponding electrical conductor, it can be specially bent so that the temperature sensor is pressed against a flat surface instead of against a curved one.

Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the contact section of the electrical conductor and the fastening section of the high-voltage terminal extend essentially in the circumferential direction of the stator, whereby a particularly compact design of the stator can be supported.

According to a further particularly preferred embodiment of the invention, it can be provided that the stator winding is designed as a hairpin winding or as a wave winding. Furthermore, the invention can also be further developed in such a way that the temperature sensor is arranged on a radially outer layer of the hairpin winding or the wave winding. The advantage of this configuration is that, for example, when cooling a rotor, the radially outermost electrical conductors of a stator winding are subjected to the highest thermal load and are therefore well suited for measuring the temperature. With rotor cooling, which is also sometimes referred to as centrifugal cooling via the rotor (spin spray), the radially inner electrical conductors of the winding head are usually well cooled, but the cooling capacity decreases towards the radially outer electrical conductors.

In a likewise preferred embodiment variant of the invention, it can also be provided that the high-voltage terminal has a ring segment-like insulating body, in particular formed by a plastic, on which the fastening section is designed for fastening the temperature sensor. It can also be advantageous to further develop the invention in such a way that the insulating body has at least one guide means for guiding at least one cable of the temperature sensor, by means of which the position of the cable relative to the insulating body is fixed. The advantage that can be achieved in this way is that a cable connected to the temperature sensor can be guided in a defined and secure manner on or through the insulation body.

• • Bereitstellung eines zylinderringförmig ausgebildeten Stators, der eine Mehrzahl von Statorzähnen aufweist, welche in Umfangsrichtung zwischen benachbarten Statorzähnen jeweils eine sich in radialer Richtung erstreckende sowie in axialer Richtung durch den Stator verlaufende Statornut definieren,
• • Einsetzen einer bestrombare Statorwicklung umfassend eine Mehrzahl von elektrischen Leitern in die Statornuten, so dass die elektrischen Leiter an einer ersten Stirnseite des Stators unter Ausbildung eines ersten Wickelkopfes aus dem Stator austreten,
• • Bereitstellung eines Hochvoltterminals zum Anschluss der Statorwicklung an eine Bestromung
• • Befestigung eines Temperatursensors an einer dem ersten Wickelkopf im späteren montierten Zustand zugewandten Seite des Hochvoltterminals,
• • Axiales Aufsetzen des Hochvoltterminals auf den ersten Wickelkopf in axialer Richtung an den Wickelkopf, so dass das Hochvoltterminal den Wickelkopf zumindest abschnittsweise überdeckt,
• • und der an dem Hochvoltterminal befestigte Temperatursensor an einem der elektrischen Leiter des Wickelkopfes anliegt.

The object of the invention is further achieved by a method for producing a stator for an electrical machine comprising the following steps:

• • Provision of a cylindrical ring-shaped stator which has a plurality of stator teeth, which in the circumferential direction between adjacent stator teeth each define a stator groove which extends in the radial direction and runs through the stator in the axial direction,
• • Inserting a stator winding that can be energized and comprising a plurality of electrical conductors into the stator slots, so that the electrical conductors emerge from the stator at a first end face of the stator to form a first winding head,
• • Provision of a high-voltage terminal for connecting the stator winding to a power supply
• • Fastening a temperature sensor on a side of the high-voltage terminal that faces the first winding head in the later assembled state,
• • Axial placement of the high-voltage terminal on the first winding head in the axial direction on the winding head, so that the high-voltage terminal covers the winding head at least in sections,
• • and the temperature sensor attached to the high-voltage terminal is in contact with one of the electrical conductors of the winding head.

The invention will be explained in more detail below using figures without restricting the general idea of the invention.

• 1 eine elektrische Maschine in einer Querschnittsdarstellung
• 2 eine erste perspektivische Ansicht eines Stators mit auf dem Wickelkopf aufgesetztem Hochvoltterminal,
• 3 eine zweite perspektivische Ansicht eines Stators mit auf dem Wickelkopf aufgesetztem Hochvoltterminal,
• 4 eine dritte perspektivische Ansicht eines Stators mit auf dem Wickelkopf aufgesetztem Hochvoltterminal ohne den Isolationskörper,
• 5 eine vierte perspektivische Ansicht eines Stators mit auf dem Wickelkopf aufgesetztem Hochvoltterminal,

It shows:

• 1 an electrical machine in a cross-sectional view
• 2 a first perspective view of a stator with a high-voltage terminal placed on the winding head,
• 3 a second perspective view of a stator with a high-voltage terminal placed on the winding head,
• 4 a third perspective view of a stator with a high-voltage terminal placed on the winding head without the insulation body,
• 5 a fourth perspective view of a stator with a high-voltage terminal placed on the winding head,

The 1 shows a stator 1 for an electrical machine 2, wherein the stator 1 is designed in the shape of a cylindrical ring and has a plurality of stator teeth 3, which in the circumferential direction between adjacent stator teeth 3 each have a stator groove 4 which extends in the radial direction and runs through the stator 1 in the axial direction define in which a currentable stator winding 5 comprising a plurality of electrical conductors 6 is inserted.

How to use the 2-5 clearly recognized, these electrical conductors 6 occur on a first end face 7 of the stator 1, forming a first th winding head 8 from the stator 1. In the axial direction, a high-voltage terminal 9 for connecting the stator winding 5 to a current supply adjoins the winding head 8 and the high-voltage terminal 9 covers the winding head 8 at least in sections.

On a side of the high-voltage terminal 9 facing the winding head 8, a temperature sensor 10 is attached, which rests on one of the electrical conductors 6 of the winding head 8. The electrical conductor 6, on which the temperature sensor 10 rests, has a contact section 11, which runs essentially parallel to a fastening section 12 of the high-voltage terminal 9, to which the temperature sensor 10 is fastened to the high-voltage terminal 9. The 2-5 It can also be clearly seen that the contact section 11 of the electrical conductor 6 and the fastening section 12 of the high-voltage terminal 9 are essentially flat and the contact section 11 of the electrical conductor 6 and the fastening section 12 of the high-voltage terminal 9 extend essentially in the circumferential direction of the stator 1.

The stator winding 5 can be designed as a hairpin winding or as a wave winding, with the temperature sensor 10 being arranged on a radially outer layer of the hairpin winding or the wave winding.

What the 2-3 can also be seen is that the high-voltage terminal 9 has a ring segment-like insulating body 15, in particular formed by a plastic, on which the fastening section 12 is designed for fastening the temperature sensor 10. The insulation body 15 can also have at least one guide means 16 for guiding at least one cable 17 of the temperature sensor 10, through which the position of the cable 17 relative to the insulation body 15 is fixed.

Below is a process for producing a stator 1, as shown in the 1-5 is known, described.

First, a cylindrical ring-shaped stator 1 is provided, which has a plurality of stator teeth 3, which in the circumferential direction between adjacent stator teeth 3 each define a stator groove 4 which extends in the radial direction and runs in the axial direction through the stator 1, followed by the insertion of an energized one Stator winding 5 comprising a plurality of electrical conductors 6 in the stator slots 4, so that the electrical conductors 6 emerge from the stator 1 at a first end face 7 of the stator 1 to form a first winding head 8. Such a wound stator 1 is, for example 1 refer to.

Furthermore, a high-voltage terminal 9 is provided for connecting the stator winding 5 to a current supply and a temperature sensor 10 is fastened to a side of the high-voltage terminal 9 that faces the first winding head 8 in the later assembled state.

Then the high-voltage terminal 9 is placed axially on the first winding head 8 in the axial direction on the winding head 8, so that the high-voltage terminal 9 covers the winding head 8 at least in sections,
and the temperature sensor 10 attached to the high-voltage terminal 9 rests on one of the electrical conductors 6 of the winding head 8. This condition is, for example, in the 2-5 shown.

The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be viewed as limiting but rather as illustrative. The following patent claims are to be understood as meaning that a stated feature is present in at least one embodiment of the invention. This does not exclude the presence of other features. If the patent claims and the above description define 'first' and 'second' features, this designation serves to distinguish two similar features without establishing a ranking.

Reference symbol list

1

stator

2

electric machine

3

stator teeth

4

stator slot

5

Stator winding

6

Ladders

7

front side

8th

winding head

9

High-voltage terminal

10

Temperature sensor

11

Contact section

12

Fastening section

15

Insulation body

16

Leadership tools

17

Cable

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102019111825 A1 [0006]
• DE 102018119831 A1 [0006]
• US 2019/0372422 A1 [0007]

Claims (9)

Stator (1) for an electrical machine (2), wherein the stator (1) is cylindrical ring-shaped and has a plurality of stator teeth (3), which in the circumferential direction between adjacent stator teeth (3) each extend in the radial direction and in the axial Define the direction through the stator (1) running stator groove (4), in which a currentable stator winding (5) comprising a plurality of electrical conductors (6) is inserted, which on a first end face (7) of the stator (1) to form a The first winding head (8) emerges from the stator (1), with a high-voltage terminal (9) adjoining the winding head (8) in the axial direction for connecting the stator winding (5) to a current supply and the high-voltage terminal (9) connecting the winding head (8). at least partially covered, characterized in that on a side of the high-voltage terminal (9) facing the winding head (8), a temperature sensor (10) is attached, which rests on one of the electrical conductors (6) of the winding head (8). stator (1). Claim 1 , characterized in that the electrical conductor (6), on which the temperature sensor (10) rests, has a contact section (11) which runs essentially parallel to a fastening section (12) of the high-voltage terminal (9) on which the temperature sensor ( 10) is attached to the high-voltage terminal (9). Stator (1) according to one of the preceding claims, characterized in that the contact section (11) of the electrical conductor (6) and the fastening section (12) of the high-voltage terminal (9) are essentially flat. Stator (1) according to one of the preceding claims, characterized in that the contact section (11) of the electrical conductor (6) and the fastening section (12) of the high-voltage terminal (9) extend essentially in the circumferential direction of the stator (1). Stator (1) according to one of the preceding claims, characterized in that the stator winding (5) is designed as a hairpin winding or as a wave winding. stator (1). Claim 5 , characterized in that the temperature sensor (10) is arranged on a radially outer layer of the hairpin winding or the wave winding. Stator (1) according to one of the preceding claims, characterized in that the high-voltage terminal (9) has a ring segment-like insulating body (15), in particular formed by a plastic, on which the fastening section (12) is designed for fastening the temperature sensor (10). stator (1). Claim 7 , characterized in that the insulating body (15) has at least one guide means (16) for guiding at least one cable (17) of the temperature sensor (10), through which the position of the cable (17) relative to the insulating body (15) is fixed. Method for producing a stator (1) for an electrical machine (2) comprising the following steps: • Provision of a cylindrical ring-shaped stator (1), which has a plurality of stator teeth (3), which in the circumferential direction between adjacent stator teeth (3) each have a stator groove (4) which extends in the radial direction and runs in the axial direction through the stator (1). ) define, • Insertion of an energized stator winding (5) comprising a plurality of electrical conductors (6) into the stator slots (4), so that the electrical conductors (6) are on a first end face (7) of the stator (1) to form a first winding head ( 8) emerge from the stator (1), • Provision of a high-voltage terminal (9) for connecting the stator winding (5) to a power supply • Attachment of a temperature sensor (10) to a side of the high-voltage terminal (9) facing the first winding head (8) in the later assembled state, • Axial placement of the high-voltage terminal (9) on the first winding head (8) in the axial direction on the winding head (8), so that the high-voltage terminal (9) covers the winding head (8) at least in sections, • and the temperature sensor (10) attached to the high-voltage terminal (9) rests on one of the electrical conductors (6) of the winding head (8).

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