DE102020121273A1 - Electric machine with protective mechanism on a welded joint; and methods of assembling the electrical machine - Google Patents

Abstract

The invention relates to an electrical machine (1) for a motor vehicle drive, having a coil component (4) having a base body (2) and a coil winding (3) accommodated inside the base body (2), and a connection component (4) connected to the coil winding (3). 5), wherein one end (6) of a first wire (7) of the coil winding (3) is connected via a welded joint (8) to one end (9) of a second wire (10) of the connection component (5), two being connected to the sections (11, 12) of the two wires (7, 10) running towards each end (6, 9) are held transversely to one another via a holding element (13). The invention also relates to a method for assembling this electrical machine (1).

Description

The invention relates to an electrical machine for a motor vehicle drive, with a coil component having a base body and a coil winding accommodated within the base body, and with a connection component connected to the coil winding, one end of a first wire of the coil winding being connected via a welded connection to one end of a second wire of the Connection component is connected. Furthermore, the invention relates to a method for assembling this electrical machine.

Prior art known to the applicant is in 5 shown. With this 5 a connection area between a first wire 7' and a second wire 10' on an electrical machine 1' can be seen. The wires 7' and 10' are connected to one another via a welded connection 8'. It has been found that during assembly or during operation of the electrical machine 1', such large forces F can act on the welded joint 8' that the welded joint 8 may also be damaged. Especially with the in 5 Due to the force F applied to the second wire 10', a relative adjustment of the two wires 7', 10' by an angle W can be generated, which in turn causes a high bending load on the welded joint 8'. Breaking of the welded connection 8' can even lead to a total failure of the system.

It is therefore the object of the present invention to provide an electrical machine that is significantly more robust with regard to the forces that occur during operation or during assembly.

According to the invention, this is achieved in that two sections of the two wires running towards the respective end are held/supported transversely to one another via a holding element. "Transverse" means a direction transverse (preferably perpendicular) to an imaginary reference line extending from the section to the end of the same wire.

The holding element provides a simple means of protecting the wires from undesired tilting and consequently the welded connection from excessive bending stress. The existing connections of the wires are therefore much more robust. Furthermore, there is the advantage that the holding element serves as a protective mechanism both for assembly and for operation. This further simplifies assembly and significantly increases the fatigue strength of the electrical machine.

Further advantageous embodiments are claimed with the dependent claims and explained in more detail below.

Accordingly, it is advantageous if the retaining element is designed in such a way that it encompasses/clasps the sections together at least from two opposite sides. As a result, the holding element can be fixed to the wires in a simple manner.

It is also advantageous if the holding element is a sleeve that (completely) surrounds/encloses the sections. This secures the wires to one another with the most stable connection possible. Alternatively, it is also expedient if the holding element is implemented as a clip (i.e. with a cross-sectional shape open on one side).

It has proven to be expedient if the connection component has a busbar, for example in the form of a high-voltage terminal, and/or power electronics, for example having various electrical components. As a result, the electrical machine is connected to other components as directly as possible.

For a further simplified assembly, it is also advantageous if the holding element is materially connected to at least one of the two wires, more preferably to each of the two wires. In this regard, it has proven to be particularly advantageous if this material connection is implemented as a welded connection. This keeps the retaining member firmly in the intended location of the two sections.

It has been found to be particularly expedient if the holding element is connected to at least one of the two wires via a spot weld, preferably to a spot weld with both wires. This results in a connection of these components that is easy to automate.

As an alternative to the integral connection, it is also advantageous if the holding element is connected in a non-positive and/or positive manner to at least one of the two wires, more preferably to both wires. This connection causes the two wires to fit together as tightly as possible.

In this context, it has proven to be expedient if the holding element is connected to at least one of the two wires, preferably even to both wires, by means of a caulking.

In order to fix the wires to one another as robustly as possible, it is also advantageous if the holding element has a cross-sectional shape that at least partially follows the peripheral sides of the sections to be connected.

In this context, it is advantageous if the holding element (like the wires) has an essentially square/rectangular cross-sectional shape, preferably forming the sleeve. As an alternative to this, it is also advantageous if the wires are implemented as round and consequently the holding element has a round or elliptical cross-sectional shape. A round wire and a rectangular wire are also clasped together in a further preferred embodiment, so that the holding element is designed to be round/elliptical in sections and rectangular in sections. As a result, the holding element is cleverly adapted to the corresponding shape of the wires. More preferably (e.g. when converting the holding element as a clamp), the cross-sectional shape of the holding element is open on one side.

If an insulating layer is applied at least in the area of the welded connection, preferably by means of a powder bath dipping process, reliable insulation of the wires is provided.

Furthermore, the invention relates to a method for assembling an electrical machine according to the invention according to at least one of the above-described versions, wherein first a first wire associated with the coil winding is connected with its first straight section, which adjoins one end of the first wire, next to a parallel to second section of a second wire of the connection component running along the first section, so that one end of the second section is arranged at the same height as the end of the first wire, after which a holding element is attached to both sections, so that the two sections in their transverse direction are fixed to one another by the holding element, and then the ends are connected to one another via a welded joint. This results in the most exact possible positioning of the wires and their ends relative to one another, even during assembly.

In other words, according to the invention, a protective mechanism for a weld point (weld connection) for electrical machines is implemented. In the electric machine, the welded connection for busbars or general conductors is protected by an additional component (retaining element) so that a tensile, compressive, torsional or shearing load is shifted from the welded connection to the additional component. More specifically, a sleeve is slid over the loose busbars (first wire and second wire) to pre-position them for a weld. The sleeve is initially loose and therefore not connected to the busbars. However, it is advantageous to connect this sleeve to the busbars by spot welding or by mechanical deformation. The busbars can then be welded together.

The invention will now be explained in more detail below with reference to figures.

• 1 eine Schnittdarstellung einer erfindungsgemäßen elektrischen Maschine gemäß einem bevorzugten Ausführungsbeispiel, mit der eine Verbindungsstelle zwischen zwei Drähten einer Spulenwicklung und eines Anschlussbauteils samt einem zur Sicherung der zwischen diesen Drähten vorhandenen Schweißverbindung dienenden Halteelement detailliert zu erkennen sind,
• 2 eine perspektivische Darstellung der in 1 bereits dargestellten Verbindungsstelle,
• 3 eine perspektivische Darstellung des in den 1 und 2 eingesetzten, als Hülse ausgebildeten Halteelementes, womit eine Querschnittsform dieses Halteelementes näher zu erkennen ist,
• 4 eine perspektivische Darstellung einer seitens ihres Stators und eines Anschlussbauteils zu erkennenden elektrischen Maschine, sowie
• 5 eine Schnittansicht einer gemäß dem Stand der Technik ausgebildeten elektrischen Maschine.

Show it:

• 1 a sectional view of an electrical machine according to the invention according to a preferred exemplary embodiment, with which a connection point between two wires of a coil winding and a connection component together with a holding element serving to secure the welded connection between these wires can be seen in detail,
• 2 a perspective view of the 1 connection point already shown,
• 3 a perspective view of the 1 and 2 inserted holding element designed as a sleeve, whereby a cross-sectional shape of this holding element can be seen in more detail,
• 4 a perspective view of an electrical machine that can be seen from its stator and a connection component, and
• 5 a sectional view of a trained according to the prior art electrical machine.

The figures are only of a schematic nature and serve exclusively for understanding the invention. The same elements are provided with the same reference numbers.

with 4 First, a basic structure of a coil component 4 of an electrical machine 1 implemented according to the invention is shown. In this embodiment, the coil component 4 is implemented as a stator of the electrical machine 1, which is arranged fixed to the housing during operation. In this connection it should be pointed out that the coil component 4 is alternatively implemented as a rotor in further embodiments according to the invention.

The electric machine 1 therefore has, in the usual way, an in 4 For the sake of clarity, the rotor is not shown in any more detail and is arranged so as to be rotatable radially inside the coil component 4 (stator) which is implemented in the form of a ring. In its preferred area of application, the electric machine 1 is used to drive a motor vehicle and is then used in a motor vehicle drive train of a purely electrically or hybrid motor vehicle.

The coil component 4, as also in 4 illustrated, has an annular base body 2 . The base body 2 consists of a laminated core. The base body 2 consequently has a plurality of individual sheets stacked one on top of the other to form a package, all of which are of the same design.

The base body 2 is provided with a plurality of grooves 19 towards a radial inner side 18 . The grooves 19 run in the axial direction, i. H. along an imaginary axis of rotation of the rotor, in a straight line and penetrate the base body 2 completely. The grooves 19 are open towards the inside 18 . The grooves 19 are distributed in the circumferential direction on the inside 18 .

A coil winding 3 is accommodated on the base body 2 or in the base body 2 . Wires 7 of the coil winding 3 run with corresponding longitudinal sections within the grooves 19 and are each folded over to an axial end face 20a, 20b of the base body 2 in the usual way. The individual (first) wires 7 of the coil winding 3 therefore cross each other in the usual way. with 4 a first end face 20a of the base body 2 is illustrated. Individual (first) wires 7 of the coil winding 3 are each connected to a (second) wire 10 of a connection component 5 .

In this embodiment, the connecting component 5 is designed as a simple busbar for further connecting the coil winding 3 to a controller. However, it is also alternatively possible to implement this connection component 5 in a different way, for example already as power electronics/a power electronics module with further electronic components.

With the 1 and 2 a connection point 22 designed according to the invention between a first wire 7 and a second wire 10 can be seen in more detail. The first wire 7 is electrically connected at its (first) end 6 via a welded connection 8 to a (second) end 9 of the second wire 10 which is arranged at the same height as the first end 6, in order to ensure that the individual phases of the electrical machine 1 are energized accordingly enable.

In this way, according to 4 other connection points 22 are also implemented. These connection points 22 are each provided between a first wire 7 of the coil winding 3 and a second wire 10 of the connection component 5 .

In 1 the first wire 7 can be seen from its axially protruding first section 11 . Furthermore, a second section 12 of the second wire 10 running parallel to this first section 11 can be seen. These two sections 11, 12 run straight away from the respective end 6, 9 and parallel to one another. The weld joint 8 connecting the two ends 6, 9 is implemented as an attached teardrop-shaped weld. The welded connection 8 leads directly to the electrical connection of the two wires 7, 10.

In order to prevent the two wires 7, 10 at their sections 11, 12 from tilting relative to one another, a holding element 13 in the form of a sleeve 21 is attached to these sections 11, 12 according to the invention. The holding element 13, as it is alone in 3 can be seen in more detail, surrounds / clasps both sections 11, 12, so that they are fixed against tilting, ie in the transverse direction / transverse to their longitudinal extent to each other. The holding element 13 consequently serves as an additional connecting element of the two sections 11, 12 at a distance from the welded joint 8.

The cross-sectional shape 16 of the holding element 13 is matched to the outer shape of the peripheral sides 14, 15 of the wires 7, 10 in such a way that it lies flat against the peripheral sides 14, 15 of the two wires 7, 10. Since the two sections 11, 12 have a quadrangular cross-section (describe each half), the holding element 13 consequently also has a quadrangular cross-sectional shape 16. In this context it should be pointed out that other cross-sectional shapes 16 for the holding element 13 are also conceivable in further embodiments. Accordingly, with a circular cross-sectional shape of the sections 11, 12, the holding element 13 preferably also has a circular or elliptical shape.

Furthermore, it is expedient if the holding element 13 is fastened to the two wires 7 and 10 via a connection, in order to also be fixed in the longitudinal direction of the sections 11, 12. The holding element 13 is preferably attached to each section 11, 12 by means of a further welded connection, preferably in the form of a spot weld. As an alternative to this, it is also possible in further embodiments if the holding element 13 is connected to each section 11, 12 via a non-positive and/or positive connection, such as caulking is bound. According to further embodiments, it is also possible to connect the holding element 13 to only one of the two sections 11 or 12 .

It should also be pointed out that the welded connection 8 is preferably (completely) coated with an insulation layer 17 . The insulating layer 17 is preferably applied using a powder bath dipping process.

In connection with the 1 and 2 a preferred method for assembling the electric machine 1 should also be pointed out. In this assembly method, before the two wires 7, 10 are connected by applying the weld joint 8, the two wires 7, 10 are arranged with their two sections 11, 12 parallel to one another, so that the sections 11, 12 are preferably partially supported on one another and the ends 6, 9 are at the same height (ie in the same plane next to each other). Following this, the holding element 13/the sleeve 21 is pushed onto both sections 11, 12, so that the two sections 11, 12 are fixed to one another in their transverse direction.

The holding element 13 is then preferably connected to the first wire 7 and the second wire 10 by means of the material connection or the non-positive and/or positive connection. Then the welded connection 8 is then applied. As an alternative to this, the welded joint 8 can also be applied before the holding element 13 is connected to the wires 7 , 10 . The ends 6 , 9 of the wires 7 , 10 , which are arranged at the same height, are connected/welded to one another via the welded connection 8 .

In other words, the inventive solution consists in protecting the weld (weld 8) by an additional component (retaining element 13) and the loading of tensile, compressive, torsional and shear stresses from the weld 8 on this additional component to relocate.

In accordance with the inventive solution, a sleeve 21 is inserted over the still loose busbars (wires 7, 10) in a preferred embodiment. This pre-positions them for the welding process. The sleeve 21 is initially still loose and therefore not fixed to the busbars. It is conceivable to connect the sleeve 21 to both busbars via a spot weld or via mechanical deformation. The two wires 7, 10/busbars can then be welded.

In the present case, two rectangular wires (wires 7, 10) are connected to one another. Therefore, the sleeve 21 can also have a rectangular cross section (cross-sectional shape 16). However, any other cross section, for example a round cross section, is also conceivable. The wires 7, 10 to be connected can also be round.

With the help of the additional component in the form of the sleeve 21, the load on the weld point is transferred to the sleeve 21. The weld is thus protected against gaping. Corresponding loads can be: Compensation of tolerances; assembly tolerances; thermal expansions.

The additional component is also so small that the insulation process can be carried out using what is known as powder bath immersion.

The connection according to the invention by means of the sleeve 21 results in the following advantages: The sleeve 21 pre-positions the two busbars/wires 7, 10 to be connected. The load of the weld is transferred to the sleeve 21. It turns out simple system. In addition, previous processes such as insulation, joining, etc. remain unaffected.

Reference List

1

electric machine

2

body

3

coil winding

4

coil assembly

5

connecting component

6

first end

7

first wire

8th

welded joint

9

second end

10

second wire

11

first section

12

second part

13

holding element

14

first perimeter page

15

second peripheral side

16

cross-sectional shape

17

insulation layer

18

inside

19

groove

20a

first face

20b

second face

21

sleeve

22

connection point

Claims (8)

Electrical machine (1) for a motor vehicle drive, with a coil component (4) having a base body (2) and a coil winding (3) accommodated within the base body (2), and with a connection component (5) connected to the coil winding (3), wherein one end (6) of a first wire (7) of the coil winding (3) is connected via a welded connection (8) to one end (9) of a second wire (10) of the connection component (5), characterized in that two to the respective Sections (11, 12) of the two wires (7, 10) extending towards the end (6, 9) are held transversely to one another via a holding element (13). Electrical machine (1) according to claim 1 , characterized in that the holding element (13) is a sleeve (21) surrounding the sections (11, 12). Electrical machine (1) according to claim 1 or 2 , characterized in that the holding element (13) is cohesively connected to at least one of the two wires (7, 10). Electrical machine (1) according to claim 3 , characterized in that the holding element (13) is connected via at least one spot weld to at least one of the two wires (7, 10). Electrical machine (1) according to claim 1 or 2 , characterized in that the holding element (13) is non-positively and/or positively connected to at least one of the two wires (7, 10). Electrical machine (1) according to claim 5 , characterized in that the holding element (13) is connected to at least one of the two wires (7, 10) by caulking. Electrical machine (1) according to one of Claims 1 until 6 , characterized in that the holding element (13) has a cross-sectional shape (16) at least partially following the peripheral sides (14, 15) of the sections (11, 12) to be connected. Method for assembling an electrical machine (1) according to one of Claims 1 until 7 , wherein initially a first wire (7) associated with the coil winding (3) with its first straight section (11) adjoining one end (6) of the first wire (7) is connected next to a section (11 ) running, second section (12) of a second wire (10) of the connecting component (5) is arranged, so that one end (9) of the second section (12) is at the same height as the end (6) of the first wire (7) is arranged, a holding element (13) is then attached to both sections (11, 12), so that the two sections (11, 12) are fixed to one another in their transverse direction by the holding element (13), and then the ends (6 , 9) are connected to one another via a welded connection (8).

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