EP3935715A1

EP3935715A1 - Interconnection assembly and stator for an electrical machine

Info

Publication number: EP3935715A1
Application number: EP20708489.8A
Authority: EP
Inventors: Ralf Wittstadt; Katja WILLACKER; Jochen Wittmann; Sebastian Baumgart; Norbert Lohaus; Tobias Schrenk; Roland Lindwurm; Christoph Wieder
Original assignee: ZF Friedrichshafen AG
Current assignee: ZF Friedrichshafen AG
Priority date: 2019-03-05
Filing date: 2020-03-03
Publication date: 2022-01-12
Also published as: JP2022522620A; WO2020178288A1; CN113454888A; US20220149690A1; DE102019202911A1; KR20210134941A; JP7486500B2

Abstract

The present invention relates to an interconnection assembly (10) for a stator (100) of an electrical machine. The interconnection assembly (10) comprises a shaped bus bar (12), which has a first region (14), which comprises a connection point (16) of the interconnection assembly (10) for an external connection (23), a second region (18), in which a connecting point (20) for forming a connection of the bus bar (12) to a stator winding (102) is formed, and a central region (22), which connects the first region (14) and the second region (18). The first region (14) and the second region (18) are arranged in parallel planes (30, 31). The central region (22) is oriented in such a way that an angle (α) of a transition between the first region (14) and the central region (22) and an angle of a transition between the second region (18) and the central region (22) deviate from a right angle. The invention also relates to a stator (100) having an interconnection assembly (10).

Description

Circuit arrangement and stator for an electrical machine

The present invention relates to interconnection arrangements for a stator of an electrical machine. Further aspects of the invention relate to stators for electrical machines with interconnection arrangements according to the invention.

According to known concepts, stator coils or stator windings of an electrical machine can be contacted by means of an interconnection arrangement with external connection points or power connections in order to apply a respective voltage to the individual phases of the winding by means of an electrical circuit or power electronics.

Known interconnection arrangements have, for example, three switching rings that are received within a carrier. The carrier can also position the rings and electrically isolate the switching rings from one another. The switching rings are firmly fixed in the carrier.

Switching rings have, for example, coil connection areas for connecting the circuit arrangement to the stator winding, and external connection areas for connecting the interconnection arrangement to external connections. Via the external connection areas, the individual stator windings are each contacted with an external connection, for example with power cables from the power electronics.

US 2003 094 879 A1 shows a centralized power distribution unit for a thin brushless vehicle motor with multiple busbars, a resin insulation layer that covers the busbars, and an insulating holder with several Haltu th that hold the busbars. The bus bars are bent in a thickness direction to form a substantially annular shape. Connection sections of the busbars protrude from an embedded area of the busbar at a right angle.

US 2005 082 923 A1 shows a stator of a rotating electrical machine with a stator core, several pairs of coils and several lines. The stator core includes a laminated core assembly formed by laminating thin steel plates in a cylindrical shape. The stator core has a plurality of slots at intervals along a circumferential direction.

In known concepts of interconnection arrangements, a high degree of rigidity of elements of the interconnection arrangement can lead to mechanical stresses occurring at electrical contact points when the interconnection arrangement is installed. As a result, a mechanical contact between two electrical conductors, for example, can deteriorate and thus an electrical contact between the electrical conductors can also deteriorate.

A flexible design of connecting elements, for example a continuation of wound, flexible wire turns of a coil, could avoid mechanical stresses in an installed state of the interconnection arrangement, but with such concepts, the effort involved in assembly can be increased. In the case of such connections, the individual flexible conductors (for example wire or lamellas) must each be precisely pre-positioned, which can be made difficult by the simple deformability of a winding wire.

The object of the invention is to provide an improved interconnection arrangement for a stator of an electrical machine which, when installed, avoids mechanical stresses at the respective contacting points and / or which can be installed in a simple manner.

The object is achieved according to the subjects of the independent patent claims. Further aspects and developments of the invention, which can have additional advantages, are described in the dependent claims, the following description and in connection with the figures shown.

Accordingly, an interconnection arrangement for a stator of an electrical machine's rule is proposed. The interconnection arrangement includes at least one shaped busbar with multiple areas. A first area of the busbar comprises a connection point of the interconnection arrangement for an external connection, For example, for contacting the interconnection arrangement with power electronics for controlling a stator winding of the stator. The busbar comprises a second area at which a connection point for forming a connection between the busbar and a stator winding is formed. A central area of the busbar connects the first with the second area.

The interconnection arrangement can thus be contacted with supply electronics on a first part of the busbar. On a second part of the busbar, which is formed, for example, on a switching ring segment formed by the busbar (e.g. in a common plane with the second area of the busbar), the interconnection arrangement can be contacted with a winding of a stator. The switching ring segment can be received and fixed in a housing of the interconnection arrangement.

According to the invention, the middle area is aligned such that a respective angle of a transition between the first area and the middle area and between two system areas and the middle area deviates from a right angle. In other words, a transition angle between adjacent regions is not equal to 90 °. In this case, the angle can be measured between area sections which lie outside a bending radius of a bend in the shaped busbar between the areas.

For example, the transition angle deviates from a right angle by more than a tolerance-related value. A right angle subject to tolerances can, for example, comprise 90 ° +/- 1 ° (or +/- 2 °). According to the invention, however, the transition angle is designed so that it deviates from a right angle in a planned or intentional manner.

The deviation can be, for example, more than 3 ° (or more than 5 °, more than 10 °, more than 20 °, more than 30 °, more than 40 °; more than 50 ° or more than 60 °) and / or less than 70 ° (or less than 60 °, less than 50 °, less than 40 °, less than 30 °, less than 20 ° or less than 15 °). For example, the deviation includes a value of 3 ° (or a value of 4 °; a value of 5 °, a value of 7 °; a value of 10 °, a value of 15 °; a value of 20 °, or a value of 25 °). The proposed choice of the transition angle can result in a slight, in other words slight, elasticity of the central area. This has the effect, for example, that the first area can be shifted by a certain distance (e.g. up to 1 mm, up to 2 mm or up to 3 mm) compared to the second area, with a resulting mechanical load or deformation of the busbar mainly occurs in the middle range. In other words, the central area can provide a spring effect over a small displacement path.

A value of the transition angle can be selected as a function of a distance between the first and the second area. For example, a greater deviation of the angle from a right angle can be selected in the case of a small distance than in the case of a large distance, in order nevertheless to achieve sufficient elasticity of the central area. For example, at a distance of less than 5 times the thickness of the busbar, the transition angle can deviate by at least 20 ° from a right angle, at a distance of more than 5 times and less than 10 times the thickness of the busbar deviate more than 8 ° and less than 20 ° from a right angle, and / or deviate from a right angle by less than 8 ° if the distance is more than 10 times. Thus, Ver circuit arrangements with different busbars can always bring about a length compensation required when installing the interconnection arrangement.

For example, the first and second areas are arranged in parallel planes. For example, the first area lies in a plane which is inclined by less than 1 ° (or less than 2 °, or less than 5 °) with respect to a plane of the second area. When the interconnection arrangement is installed in a stator, the planes can be aligned in the radial direction of the stator, so that, for example, contacting the interconnection arrangement with external connections can be carried out particularly easily. The second area can be stretched or compressed in the axial direction in order to compensate for tolerance distances between the first area of the busbar and the power connections.

For example, at least a partial area of the central area is aligned in a connec tion plane, with an angle between the connection plane and the the plane of the first area deviates from a right angle. The value range of the angle can be defined as described above. For example, the partial area comprises at least 50% of an area of the central area. For example, a central region (eg less than 50% of the area of the central region) of the central region can be arranged at a 90 ° angle with respect to the plane of the first or second region, and the interconnection arrangement can nevertheless effect a length compensation.

According to a development of the interconnection arrangement, the busbar has at least one curvature within the central region. In other words, the middle area can be designed with one or more further kinks or bends, for example. As a result, the elasticity of the central area can be influenced more precisely, for example. For example, curvatures can increase the elasticity of central areas with small dimensions. It is possible that the busbar is at least partially arcuate in the middle area.

For example, a thickness of the busbar is less than 20 mm (or less than 10 mm, less than 5 mm, less than 4 mm, less than 3 mm or less than 2 mm) and / or more than 1 mm (or more than 3 mm or more than 5 mm). Alternatively or in addition, a ratio of a width of the busbar to a thickness of the busbar can have at least a factor of 2 (or at least a factor of 2.5; at least a factor of 3; at least a factor of 4; or at least a factor of 5). For example, a geometry of the busbar influences the elasticity of the busbar in the middle area.

For example, the second area of the busbar forms at least part of a switching ring or a switching ring segment for the stator. The second area can extend circumferentially and adjoin the central area in a region radially outside the switching ring segment.

It is possible for the interconnection arrangement to have a single busbar or two busbars. According to one embodiment, the interconnection arrangement tion on three electrically isolated shaped busbars for contacting three phases of a stator winding. For example, a circuit arrangement for contacting a 4-phase or 5-phase winding can have 4 or 5 busbars.

The interconnection arrangement can, for example, have three shaped busbars that are electrically isolated from one another for contacting three phases of the stator winding, the respective middle areas of the busbars being arranged in different, non-parallel planes. As stated, manufacturing tolerances and the like can be compensated for by the central regions in that the central region is correspondingly deformed in the axial and / or radial direction. Due to the deformation, forces can therefore occur which act on the interconnection or the stator. In order to keep these forces low, the central areas are therefore advantageously arranged in different planes if there are several busbars, the planes preferably not running parallel. This prevents, in particular in the radial direction, any forces occurring on the individual busbars from increasing, but from being kept low and possibly canceling out or reducing each other.

For example, in the case of interconnection arrangements with several busbars, at least two busbars are designed differently. For example, the middle area of the first busbar has a curvature, while the middle area of a second busbar is straight or flat. For example, the first areas of both busbars are formed in a common plane, while the second area of the first busbar is arranged closer to the common plane than the second area of the second busbar.

The busbar is formed for example from an electrically conductive material, in particular special metal. The busbar can for example comprise copper, a copper alloy, aluminum or an aluminum alloy.

One aspect of the invention relates to a stator for an electrical machine. The stator has to contact a winding of the stator (stator winding) with a switching device direction for voltage supply of the stator winding on an interconnection arrangement according to an interconnection arrangement described above or below. The invention further relates to an electrical machine with a stator comprising a corresponding interconnection arrangement, which is contacted, for example, with power connections.

It is possible that a connection of the connection points assigned to the second area of the busbar with turns of the stator winding is non-detachable (e.g. welded connection). A connection of the power connections to the first area of the busbar can be implemented, for example, by means of a detachable connection (e.g. screw or plug connection).

According to a further development of the stator, the first area of the busbar of the circuit arrangement is arranged in a normal plane of a main axis (e.g. a rotor axis) of the stator. In other words, a normal vector of the plane of the first area lies parallel to the main axis. The elasticity of the central area of the busbar enables the first area to be moved axially by at least 1 mm, for example. For example, if the first area is shifted by up to 3 mm, only the middle area is essentially deformed.

So it is e.g. possible to bring the first area up to power connections of the electrical machine in order to compensate assembly tolerances, for example, without mechanical tension (or only insignificant mechanical tension) occurring at contact points between the interconnection arrangement and power connections and / or stator winding. Thus e.g. a reliability of an electrical contact of the contacting points can be increased.

The invention provides, for example, an interconnection arrangement with length compensation for an electric machine. The middle area can cause a slight change in length of the busbar to compensate for tolerance-related spacings during the assembly of the interconnection arrangement. Developments of the stator and the electrical machine relate to features of developments as they are already described in connection with the interconnection arrangement be. A repeated description is therefore dispensed with and the corresponding features also apply in connection with the stator and the electrical machine as disclosed.

Some examples of devices are explained in more detail below with reference to the attached figures, merely by way of example. Show it:

1 shows an exemplary embodiment of an interconnection arrangement for contacting a stator winding;

2 shows an exemplary embodiment of an interconnection arrangement with mounted supply connections;

3 shows the interconnection arrangement with supply connections in a sectional view; and

Fig. 4 shows an example of a stator of an electrical machine with an interconnection arrangement.

Fig. 1 shows an embodiment of an interconnection arrangement 10 for contacting a coil winding with power electronics of the coil winding. The circuit arrangement 10 has three busbars 12, 12a, 12b, which are each electrically isolated from one another and fixed by a holding or a housing 13 of the interconnection arrangement 10.

The busbar 12 has a first area 14 with a connection point 16 for connecting the busbar to an external connection. For example, the connection point 16 is designed to connect an external connection cable or a further busbar to the busbar 12 by means of a screw connection or plug connection. For example, the first area 14 with the connection point 16 is designed as an external connection lug.

The busbar 12 also has a second area 18 at which connection points 20 for connecting the busbar 12 to a stator winding are formed. det are. The connection points can be designed as flat, continuous surfaces in order to connect a respective turn of the coil winding with a respective connection point 20. The connection can be designed as a non-detachable connection (or detachable only under the destruction of the connection point), for example by a welded connection or a soldered connection. For example, the connection points 20 are coil connection lugs.

The busbar 12 also has a central area 22 which connects the first area 14 and the second area 18 to one another. At a transition between the first region 14 and the central region 22, that is to say at the bend in the busbar 12 between the two regions, an angle α is formed which deviates from a right angle. For example, the angle α in the example shown in FIG. 1 has a value of 100 ° and thus deviates from a right angle by 10 °. An angle β of the transition between the second region 18 and the central region 22 also has a value of 100 ° in the example shown in FIG. The angles α and β can be chosen to be identical or different. For example, one of the two angles can be an acute angle and the other a shallow angle.

For example, a thickness D of the busbar 12 is 3 mm. In connection with the special design of the angles α and β, this results in, for example, a slight elasticity of the central area. The middle area 22 can have a slight spring effect, so that a slight movement (for example by 1 mm or 2 mm) of the first area 14 in the direction of a normal vector of the first area 14 in a plane parallel to the first area 14 without a substantial mechanical Tension (for example, shear force or force in the direction of a normal vector of the parallel plane) in the first area 14 and 18 or in the second area 18. In this case, the thickness D causes, for example, sufficient rigidity of the busbar 12 at the same time, so that the first area 14 remains positioned in a predetermined position without the action of a compressive or tensile force and can therefore be contacted easily.

The interconnection arrangement 10 has, for example, three switching rings and a carrier, for example the housing 13. The switching rings can also as shown in Fig. 1 as Switching ring segments be executed. A switching ring segment is formed, for example, by the second region 18 of the busbar 12 within the housing 13.

The interconnection arrangement 10 shown in FIG. 1 is provided for a 3-phase stator winding. An electrical voltage can be applied to a respective phase via the three busbars 12, 12a, 12b. The two further busbars 12a, 12b also have respective first, second and middle areas, whose transition angles each deviate from a 90 ° angle.

The carrier can be designed as a separate carrier part and have a U-shaped profile with partition walls, in which the switching rings are mutually isolated aufgenom men. The carrier can, for example, be designed as a plastic encapsulation formed in one piece with the switching rings.

The coil connection lugs are connected to the coils in a first level. The external connection lugs are connected to the external connections on a second level. Both planes are at an axial distance from one another. To bridge the axial distance, the external connection lugs (for example, encompassing the first, second and middle areas) are e.g. Executed bent several times and have, for example, three areas in three levels.

One area, for example the second area 18, is arranged in predominantly the same plane as the coil connection lugs and forms a circumferential section protruding in the radial direction (e.g. protruding from the switching ring segment). Another area, for example the middle area 22, is an area starting from the area in e.g. section of the external connection lug which is bent in the axial direction and which is then bent to form the last area, for example the first area 14. The levels of the area and the last area are e.g. essentially parallel to each other. The plane of the further area intersects the planes of the two other areas at a predetermined angle.

An advantage can result, for example, from the fact that the predetermined angle, e.g. angle cs, is not a 90 ° angle, but either more or less than 90 ° (e.g. at least 95 ° or at most 85 °). Length compensation during assembly is achieved, for example, by the inclined design of the wider area. When screwing power connections to the external connection of the interconnection arrangement 10, the first area, which serves as the connection area, can be moved out of the plane assigned to it, for example in the direction of the plane of the second area, in order to perform the length compensation. For example, only the second area is deformed by the already existing angular position.

With a perpendicular arrangement of the middle area to the other two, on the other hand, with other interconnections, the entire interconnection could be deformed during the screwing process for contacting and thus forces could also be introduced at the welds of the coils, which e.g. could lead to a crack during operation.

Therefore, according to the inventive interconnection arrangement 10, a predetermined angular position of the central area is proposed so that, for example, a slight spring action of the busbar results.

2 shows an exemplary embodiment of an interconnection arrangement 10 with mounted supply connections 23. A supply connection 23 has a busbar 24 which forms an electrical contact with the first area 14. A mechanical connection between the busbar 24 and the busbar 12 is established by means of a 2-part fastening means 26a, 26b. The connection can be established by a screw connection.

The further supply connections 23, which contact the further busbars 12a, 12b, have corresponding busbars 24a, 24b which are mounted on the interconnection arrangement with the corresponding fastening means. In the present example, the connections of the power electronics, for example the supply connections 23, are introduced to the external connection lugs of the interconnection arrangement 10 from a side which is opposite the switching rings or points towards them. A width B of the busbar 12 is also shown in FIG. 2. A ratio of the width B to the thickness D of the busbar is greater than a factor of 2. This enables, for example, a screw connection of the busbar 12 to an external connection.

FIG. 3 shows the interconnection arrangement 10 with mounted supply connections 23 in a sectional view. It can be seen that the first area 14 and second area 18 are aligned or arranged in parallel planes 30, 31. Between the first area 14 and the second area 18, a distance 32 is provided which is defined by an extension of the central area 22. When the interconnection arrangement 10 is mounted on the stator, the distance 32 is e.g. an axial distance.

In FIG. 3 it can also be seen that the central region 22 of the busbar 12 has a curvature 34, for example a kink or bend. For example, the curvature 34 can increase the flexibility of the central region 22, so that when the distance 32 changes, only the central region 22 deforms, but no mechanical stresses at connections between the first region 14 of the busbar 12 and the busbar 24 of the Versorgungsanschlus ses, or the second area 18 of the busbar 12 and mounted Statorwicklun conditions (see. Fig. 4) arise. For example, the central region 22 can compensate for an axial change in length due to an expansion or compression of an extension of the central region in the radial direction.

Furthermore, FIG. 3 shows that the further middle region 22a is completely formed in a connecting plane 36 which is arranged at an angle α to a plane 30a of the further first region 14a. An elasticity of the central area can, for example, also be achieved with a linear extension of the central area. The first areas 14, 14a, 14b are arranged in a common plane, while the second areas 18, 18a, 18b are each arranged in different planes, for example to allow simple contacting of respective phases of a stator winding with the corresponding busbar 12, 12a, 12b to enable the interconnection arrangement. 4 shows a stator 100 of an electrical machine (not shown) with a switching device 10. The stator 100 comprises a stator winding 102. Respective windings or winding ends 104 of the stator winding 102 are firmly connected to connection points 20 of the respective busbars 12, 12a, 12b .

In order to make electrical contact with one phase of the stator winding 102, a power connection can be screwed onto the busbar 12. A tolerance-related axial distance between the first area 14 and e.g. a busbar of the power connection can be compensated for by the flexibility of the central region 22 of the busbar 12. For example, a distance between the first area 14 and the second area 18 can be reduced by compressing the central area 22 or increased by stretching the central area 22. The transition angle between the areas and / or the thickness of the busbar 12 can be selected in such a way that a change in distance between the first area 14 and the second area 18 by, for example, more than 1 mm (or more than 2 mm) and / or less than 3 mm (or less than 2 mm) is possible without mechanical stresses occurring at the connection points of the interconnection arrangement.

The provided slight flexibility or elasticity of the central region 22 leads, for example, to tolerance-related distances when contact is made between power electronics and the interconnection arrangement 10. In this case, however, the elasticity is chosen to be sufficiently low so that the outer connection points of the interconnection arrangement 10 can nevertheless remain in a predefined position and simple assembly of the power connections is made possible.

In some applications, the electrical machine is built in a housing, for example, in such a way that the connection points of the electrical machine or the wiring arrangement for making contact with external connections of the power electronics cannot be shifted or aligned with one another. The external connections of the power electronics are also fixed in their installation position. It is therefore not possible to align the two connection points. Due to tolerance chains, an axial distance of approximately 1 mm can arise between the connection points of the electric machine and the power electronics. The present invention proposes concepts according to which a wiring arrangement is provided which can compensate for such mounting tolerances between the external connection of the stator or wiring arrangement and power connections. Thus, for example, axial screw forces between the connection points of the electric machine and the power electronics do not have a negative effect on the contact points to the stator coils.

Reference symbol

10 Interconnection arrangement

12 power rail

B Width of the power rail

D thickness of the busbar

13 housing

14 first area of the power rail

16 connection point for external connection 18 second area of busbar 20 connection point for stator connection 22 middle area

a, ß transition angle

23 Supply connection

24 Power rail of the supply connection

26a, 26b fasteners

30, 31 parallel planes

32 distance

34 curvature

36 Connection level

100 stator

102 stator winding

104 end of winding

Claims

1. An interconnection arrangement (10) for a stator (100) of an electrical machine, the interconnection arrangement (10) comprising at least one shaped busbar (12), the shaped busbar (12) comprising:

a first area (14) which has a connection point (16) of the interconnection arrangement (10) for an external connection (23);

a second region (18) at which a connection point (20) for forming a connection between the busbar (12) and a stator winding (102) is formed; and a central area (22) connecting the first area (14) and second area (18),

wherein the middle area (22) is oriented so that a respective angle (et) of a transition between the first area (14) and the middle area (22) and between the second area (18) and the middle area (22) of deviates from a right angle.

2. The interconnection arrangement (10) according to claim 1,

wherein the first area (14) and the second area (18) are arranged in parallel planes (30, 31).

3. The interconnection arrangement (10) according to claim 1 or 2,

wherein at least a partial area of the central area (22) is aligned in a connecting plane (36), an angle (a) between the connecting plane (36) and the plane (30) of the first area deviating from a right angle.

4. The interconnection arrangement (10) according to one of claims 1 to 3, wherein the busbar (12) has at least one curvature (34) within the central region (22).

5. The interconnection arrangement (10) according to one of claims 1 to 4, wherein the busbar (12) is at least partially arcuate in the central region (22).

6. The interconnection arrangement (10) according to one of claims 1 to 5, wherein a thickness (D) of the busbar (12) is less than 5 mm.

7. The interconnection arrangement (10) according to one of claims 1 to 6, wherein a ratio of a width (B) of the busbar to a thickness (D) of the busbar (12) has at least a factor of 2.

8. The interconnection arrangement (10) according to one of claims 1 to 7, wherein the interconnection arrangement (10) has three mutually electrically insulated shaped current rails (12, 12a, 12b) for contacting three phases of the stator winding (102), the respective central areas (22, 22a, 22b) of the busbars (12, 12a, 12b) are arranged in different, non-parallel planes.

9. The interconnection arrangement (10) according to one of claims 1 to 8, wherein the interconnection arrangement (10) has three mutually electrically insulated shaped current rails (12, 12a, 12b) for contacting three phases of the stator winding (102), the respective first Area (14, 14a, 14b) of the busbars (12, 12a, 12b) are arranged in a common plane.

10. A stator (100) for an electrical machine,

wherein the stator (100) for contacting a stator winding (102) with an electrical switching device for supplying voltage to the stator winding (102) has a Ver circuit arrangement (10) as defined according to one of the preceding claims.

11. The stator (100) according to claim 10,

wherein a first area (14) of a busbar (12) of the interconnection arrangement (10) is arranged in a normal plane of a main axis of the stator (100), with an elasticity of a central area (22) of the busbar (12) axially displacing the first area (14) by at least 1 mm.