Method for producing a stator for an electric machine, stator for an electric machine and molding tool

Abstract

The invention relates to a method for producing a stator (1) for an electric machine, in which, in a first step, a coil carrier (2) having regularly spaced teeth (3) is provided, and then, in a second step, a plurality of partial coils (4) are wound onto the teeth (3), in which the partial coils (4) are connected to one another in groups near an end face (5) of the stator (1) by means of connecting wires (6), in a third step, the at least one connecting wire (6) is locally plastically deformed so as to form an axially inwardly projecting loop region (7a), while the connecting wire (6) is tensioned in the circumferential direction of the stator. The invention also relates to a forming tool (8) and a stator (1).

Description

Technical Field

[0001] The invention relates to a method for producing a stator for an electric machine, wherein the electric machine is designed, for example, as a brushless DC motor, and in a first step a coil carrier with regularly (mutually) spaced teeth is provided, and then in a second step a plurality of partial coils are wound onto the teeth, which partial coils are connected to one another in groups by means of connecting wires close to the end faces (i.e., the axial sides) of the stator. The invention also relates to a stator produced by means of the method and a forming tool. Background Art

[0002] The prior art for the mentioned field is already well known. For example, WO 2020 / 057898 A1, DE 10 2015 211 836 A1 and DE 10 2018 222 891 A1 disclose various winding processes for producing stators.

[0003] When producing electric machines of the type mentioned, there is an increasing demand to make the stator as compact as possible in order to be able to use the stator in various smaller installation spaces. In the designs known from the prior art, it has also been shown that the existing receiving devices for the stator windings are often relatively complex in design, requiring a relatively large number of additional components. Summary of the invention

[0004] It is therefore an object of the present invention to provide a wound stator which is compact in terms of its installation space and which has a low complexity.

[0005] This is achieved according to the invention, wherein, in the third step, at least one connecting wire is partially plastically deformed to form a loop region protruding axially inwards, and at the same time, the at least one connecting wire is tensioned in the circumferential direction of the stator. The loop region protruding axially inwards should be understood in particular as a loop region that protrudes mainly (may have a radial extension component) or only (without a radial extension component) in the axial direction (i.e., along the axis of rotation of the rotor arranged to rotate relative to the stator) and extends in the direction of the stator body. In other words, the axially inward direction indication should be understood to mean that the loop has an open, possibly narrowed area, whereby the connecting wire extends in the axial direction from the two boundaries of the opening in the circumferential direction, and the axial direction is defined relative to the end face of the stator, so that the first axial direction points away from the end face of the stator and is defined as axially outwards, while the opposite direction points from the end face to the teeth, i.e., to the stator body, and is therefore defined as axially inwards. Therefore, the closed side of the loop is spaced axially inwards relative to the open area of ​​the loop. Since the loop region protrudes axially inwards, no additional axial space is required.

[0006] This makes it possible to produce compact stator coils as easily as possible.

[0007] Further advantageous embodiments are claimed in the dependent claims and are explained in more detail below.

[0008] It is therefore also advantageous if the connecting wire and its loop region are received in at least one axially open and circumferentially surrounding receiving channel / cavity of the stator carrier. This makes the stator structure as simple as possible.

[0009] Furthermore, it is advantageous if a plurality of loop regions are formed in a distributed manner in the circumferential direction on one connecting wire and / or in a distributed manner on a plurality of connecting wires. This makes it possible to adjust the tension of the connecting wires individually in the simplest possible manner.

[0010] In the presence of at least one first loop region protruding in a first axial direction and at least one second loop region protruding in a second axial direction opposite to the first axial direction, the loop regions are variably adjustable and can be integrated into existing installation spaces.

[0011] It can be particularly advantageous that both the first loop region and the second loop region are axially located in the winding space of the stator, wherein the winding space is delimited axially by the axially outermost tangential region of the partial coil and the connecting wire. In other words, the winding space is determined by the winding of the partial coil and the connecting wire, and the connecting wire does not have a loop region. This means that there is a tangential winding, i.e., a winding in the circumferential direction, in the tangential region, wherein there may be a section in the axial direction and / or radial direction between each tangential section. However, there is an outer layer of the winding in the axial direction, which represents the axial edge region of the winding space. From the edge region or axial boundary of the winding space, all windings, and the loop region in the described case are only located in the axial inward direction. An exception to this situation may be a connection region of a winding or a connecting wire, which connects the winding or the connecting wire to a connecting element for connecting the stator to a circuit. Such a connection region is explicitly excluded from the loop region according to the present invention or does not constitute a winding space.

[0012] It has proven to be advantageous if each of the at least one loop region / multiple loop regions is produced by means of a manual pressing / extrusion process. This allows the pretensioning of the connecting wire to be adjusted individually.

[0013] It is therefore also advantageous if the at least one loop region / each of the plurality of loop regions is formed by means of a mechanical forming tool. The forming tool is designed, for example, as a pair of pliers. This ensures efficient production of the stator. As an alternative to preferably only mechanically forming the at least one loop region by means of a forming tool, it is also advantageous if the at least one loop region is automatically introduced, for example by means of a robot (using a forming tool).

[0014] For the most efficient production of the electric machine, it is also advantageous to receive the coil carrier in the second step as a linear (ie, unfolded) structure in the holding device. This means that the coil carrier is initially arranged in one plane in order to wind up the corresponding partial coil. This makes the winding process easier.

[0015] It is therefore also advantageous to bring the coil carrier into an annular configuration after the second step and before the third step. This allows at least one loop region to be introduced neatly while generating sufficient tension.

[0016] The invention further relates to a forming tool for forming a loop region on a stator coil, the forming tool having two forming jaws that can be moved relative to one another in a predetermined deformation direction, wherein two first pin-shaped projections are arranged on a first forming jaw, the two first pin-shaped projections being spaced apart from one another and each extending transversely to the deformation direction, and a second pin-shaped projection is arranged on a second forming jaw, the second pin-shaped projection also extending transversely to the deformation direction, wherein the forming jaws are designed such that the second projection can be pushed into and out of an intermediate space between the two first projections. However, the forming jaws do not need to be moved parallel to one another. Simpler or more complex relative movements between the forming jaws are also conceivable.

[0017] With regard to the shaping tool, it is also advantageous if the projections extend parallel to one another and / or perpendicularly to the deformation direction. This makes the shaping tool as easy to manufacture as possible.

[0018] For repeatable deformation, it is also advantageous if the first forming jaw has a guide groove between the first protrusions, into which a guide protrusion formed complementary to the guide groove can be inserted. The guide protrusion also preferably extends toward the guide groove, so that the guide protrusion and the guide groove are in sliding contact with each other when the forming jaws are in a specific (second) position relative to each other.

[0019] In the case where the forming jaws directly form the jaws of a pair of pliers, the forming tool can be manufactured as simply as possible.

[0020] Particularly preferably, the forming tool is intended for use in a method as described above.

[0021] The invention also relates to a stator according to claim 7 .

[0022] The annular region protruding axially inwards according to the invention allows a reduction in the axial and radial installation space.

[0023] In addition, it is also possible to provide an axially outwardly projecting loop region. This allows a variable design of the loop region depending on the available space.

[0024] In a further development, the stator can have a winding space which is delimited in the axial direction by the partial coils and the connecting wires, the axial boundaries of the winding space being defined by the tangentially extending regions of the partial coils and the connecting wires which are located axially outermost with respect to the stator. Possibly axially extending connecting regions do not make any contribution to this winding space.

[0025] Then, the loop region provided will be formed axially in the winding space and will not pass through the axial boundary of the winding space. This means that the end face of the stator cannot be extended axially due to the loop region, regardless of the axial direction in which the loop region extends.

[0026] In a further development, the stator can then be produced according to the method according to one of the above-described embodiments.

[0027] In other words, according to the invention, at least one axial loop (loop region), more preferably a plurality of axial loops, is formed on the connecting wire of the linearly wound electric motor (electric machine). The protruding wire is bent in the axial direction, possibly in the opposite direction (depending on the pole), in particular by means of a pin-shaped portion (pin-shaped protrusion), so that the loops (loop regions) are formed. These axial loops are located on the circumference of the motor and reduce the radial space requirement. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be described in more detail below with reference to the accompanying drawings.

[0029] In the attached picture:

[0030] Figure 1 shows a perspective view of a circumferential region of a stator for an electric machine produced according to the invention in accordance with a first exemplary embodiment, wherein two (first) loop regions formed on the connecting wire can be clearly seen;

[0031] Figure 2 Shown according to Figure 1 A perspective view of another circumferential region of the stator, wherein a second loop region can be seen, which protrudes opposite to the first loop region;

[0032] Figure 3 A plan view of a holding device for producing a stator according to the invention is shown, wherein a plurality of partial coils are already wound on a linearly arranged coil carrier;

[0033] Figure 4 shows a plan view of a stator according to the invention in an intermediate production state, wherein the connecting wires have not yet been plastically deformed to form the loop region, but the various locations to be introduced into the loop region have been marked;

[0034] Figure 5 shows a plan view of a forming tool for forming a loop region with a connecting wire already inserted, the forming tool being in a first position in which the connecting wire has not yet been plastically deformed;

[0035] Figure 6 Shows Figure 5 a plan view of a forming tool of , wherein the forming tool is in a second position, in which the two forming jaws of the forming tool are pushed into each other and the connecting wire is thereby plastically deformed to form a loop region;

[0036] Figure 7 A perspective view of a forming tool according to the invention in the region of its forming jaws is shown;

[0037] Figure 8 shows a plan view of a forming tool according to the invention, which clearly shows the design of the forming tool as a pair of pliers;

[0038] Fig. 9 A flow chart is shown for explaining the production method according to the present invention.

[0039] The drawings are merely schematic in nature and are only useful for understanding the invention. Identical elements are provided with the same reference numerals. DETAILED DESCRIPTION

[0040] Combination Figure 1 , Figure 2 and Figure 4 A stator 1 produced according to the invention is illustrated. The stator 1 is part of an electric machine (also referred to as an electric motor), which is not further shown for the sake of clarity. The electric machine is preferably designed as a brushless DC motor. In addition to the annular stator 1, the electric machine usually also has a rotor arranged radially (radially being a direction perpendicular to the axis of rotation of the rotor) within the stator 1. The rotor in turn can be connected or has conventionally been connected to an output shaft protruding axially (axially being a direction along / parallel to the axis of rotation of the rotor) from the stator 1 in order to drive other components during operation, preferably in the drive train of a motor vehicle.

[0041] The production of the stator 1 according to the invention is Fig. 9 In general, and in combination Figures 1 to 6 To produce the stator 1, first provide Figure 3 The coil carrier 2 shown in FIG. 1 (in a first step a)). The coil carrier 2 is initially linear, ie not wound. Figure 3 , the coil carrier 2 is received on a holding device 9 for winding the coil arrangement / stator coil.

[0042] Subsequently (in a second step b)), the coil arrangement is wound onto the coil carrier 2 in the form of a plurality of partial coils 4. Figure 3 In the embodiment, the coil carrier 2 has a plurality of teeth 3 arranged adjacent to each other at regular intervals along its linear structure 10. Partial coils 4 are wound on each tooth 3 and the partial coils 4 are combined / connected to each other in groups according to how the stator is connected and form the upper stator coil.

[0043] Figure 3 It is also clearly shown that after the winding of the coil carrier 2, a plurality of connecting wires 6 (copper wires) for connecting the partial coils 4 associated with the group protrude towards the rear end face 5 / axial side of the stator 1 and extend at least partially along the extension (here linear) of the coil carrier 2.

[0044] In such Figure 3 After the winding process of the partial coil 4 shown in FIG. Figure 4 , the coil carrier is brought into an annular structure 11 intended for use in an electric machine. The connecting wires therefore extend in the circumferential direction of the stator 1 and are positioned accordingly.

[0045] Subsequently, in a third step c) of the method according to the invention, the connecting wires 6 which connect the partial coils 4 to one another in groups are locally plastically deformed, whereby the connecting wires are automatically prestressed in the circumferential direction.

[0046] exist Figure 1 and Figure 2 In the figure, it can be clearly seen that a plurality of loop regions 7a, 7b have been introduced specifically by this plastic deformation. Figure 1 2 shows two first loop regions 7a on a single connecting wire 6. The two loop regions 7a extend in a first axial direction of the stator 1 and are located radially directly from the outside on the coil carrier 2. It should be emphasized that the axial extension of the loop region 7a is located within the winding space 21, i.e. the loop region 7a does not occupy additional axial installation space. The winding space 21 is delimited outwardly in the axial direction by the tangential regions of the partial coil 4 and the connecting wire 6.

[0047] Figure 2 , a second loop region 7b is shown, which extends in a second axial direction opposite to the first axial direction. The second loop region 7b is arranged on the other connecting wire 6 and also rests radially on the coil carrier 2 from the outside. In this case, the second loop region 7b is also always arranged axially in the winding space 21.

[0048] In this way, the loop areas 7a, 7b on the corresponding connecting wires are formed Figure 4At the positions D1, D2 and D3 of the stator shown in FIG. This results in radial pretensioning and displacement of the other connecting wires 6 or sections thereof inward in the radial direction. This results in complete contact of the connecting wires 6 with the coil carrier 2 from the outside in the radial direction.

[0049] Figure 5 and Figure 6 The deformation process of the connecting wire 6, ie the deformation process for forming the loop regions 7a, 7b, is schematically illustrated. The forming process is carried out by means of a forming tool 8, which is described below. Figure 7 and Figure 8 is shown in more detail in .

[0050] according to Figure 5 , the forming tool 8 is first applied to the connecting wire 6 in a first position, so that the connecting wire 6 is arranged between the two first protrusions 14 of the first forming jaw 12 of the forming tool 8 on the one hand and the second protrusion 15 of the second forming jaw 13 of the forming tool 8 on the other hand. For plastic deformation, the forming tool 8 (i.e. the forming jaws 12, 13 relative to each other) is moved into a second position. The forming jaws 12, 13 are moved / pressed toward each other from the first position to the second position, so that the loop areas 7a, 7b are formed.

[0051] It can be seen that the two pin-shaped first projections 14 extending parallel to each other of the first forming jaw 12 are spaced apart from each other so that the pin-shaped second projection 15 of the second forming jaw 13 extending parallel to the first projection 14 can be moved / pushed into the intermediate space 16 between the two first projections 14 when the connecting wire 6 is inserted. Therefore, the distance between the facing sides of the projections 14, 15 is equal to or greater than the sum of the diameter of the second projection 15 and twice the diameter of the connecting wire 6.

[0052] Therefore, the forming tool 8 can be Figure 5 The first position shown in Figure 6 . The second position is shown in FIG.

[0053] Figure 7 and Figure 8 The forming tool 8 in an exemplary embodiment is illustrated in more detail. The forming tool 8 is designed as a pliers tool / a pair of pliers 19 and is equipped with forming jaws 12, 13 directly on its jaws. Therefore, the forming jaws 12, 13 are preferably moved only in the method along the deformation direction 20 from the first position to the second position and back again. The first protrusion 14 and the second protrusion 15 are perpendicular to this deformation direction 20 and protrude to a common side of the forming jaws 12, 13.

[0054] It can also be seen that a guide groove 17 in the form of a groove extending parallel to the first protrusions 14 is also introduced in the first forming jaw 12 between the first protrusions 14, i.e. in the intermediate space 16. A guide protrusion 18 complementary to this guide groove 17 is formed on the second forming jaw 13. Figure 5 The first position is moved to the Figure 6 The second position of the guide protrusion 18 is pushed into the guide groove 17 to achieve sliding guidance between the forming jaws 12 and 13. The second protrusion 15 is preferably formed directly on the end face of the guide protrusion 18.

[0055] For the sake of completeness, it should be noted that in another preferred exemplary embodiment, which is not shown here for the sake of brevity, the forming tool 8 is part of an automatic system, i.e. a robot, which introduces the loop areas 7a, 7b in a fully automatic manner. However, the forming tool 8 also functions according to the principles explained above and is constructed in substantially the same way.

[0056] In other words, according to the invention, the connecting wire (connecting wire 6) is formed into a loop (loop areas 7a, 7b) extending axially or obliquely using a suitable tool (forming tool 8). In this way, the existing installation space can be used in a smart way. The loop has the advantage that the plastic deformation of the loop exerts tension on the connecting wire and thus reduces the elasticity. This makes the installation space requirement even smaller.

[0057] The procedure can be performed using a manual tool (forming tool 8). Preferably however a fully automatic machine / system comprising a forming tool 8 according to the same principle will be used.

[0058] For deforming the connecting wire, the tool comprises, for example, a plurality of pins (protrusions 14, 15) that can move relative to each other. One jaw of the tool preferably comprises two pins, the opposing jaw comprises a single pin, and the single pin is arranged centrally between the other two pins. By opening and closing a pair of pliers, the pins move relative to each other. As a result, the wire / connecting wire clamped between the pair of pliers is bent in particular into a U-shaped loop.

[0059] The same principle can also be used for the forming tools 8 of a fully automatic machine, but here the movement is preferably achieved by compressed air cylinders and corresponding engagement / guiding parts, and the forming sequence is specified by the controller of the assembly system.

[0060] Reference numerals list

[0061] 1 Stator

[0062] 2 Coil carrier

[0063] 3 teeth

[0064] 4-part coil

[0065] 5 End face

[0066] 6. Connecting wires

[0067] 7a First loop area

[0068] 7b Second loop area

[0069] 8 Forming tools

[0070] 9. Holding device

[0071] 10 Linear structure

[0072] 11 Ring structure

[0073] 12 First forming jaw

[0074] 13 Second forming jaw

[0075] 14 First protrusion

[0076] 15 Second protrusion

[0077] 16 The Space Between

[0078] 17 Guide groove

[0079] 18 Guide protrusion

[0080] 19 Pliers

[0081] 20 Deformation direction

[0082] 21 Winding space

Claims

1. A method for producing a stator (1) for an electric machine, in, In a first step, a coil carrier (2) having regularly spaced teeth (3) is provided, and then in a second step, a plurality of partial coils (4) are wound onto the teeth (3), wherein the partial coils (4) are connected to each other in groups by means of connecting wires (6) close to the end faces (5) of the stator (1), characterized in that in a third step, at least one connecting wire (6) is locally plastically deformed to form an axially inwardly protruding loop region (7a), wherein the at least one connecting wire (6) is tensioned in the circumferential direction of the stator (1).

2. The method according to claim 1, It is characterized in that A plurality of loop regions (7a, 7b) are formed on the connecting wire (6) in a distributed manner along the circumferential direction and / or are formed on a plurality of connecting wires (6) in a distributed manner.

3. The method according to claim 1 or 2, It is characterized in that At least one first loop region (7a) is provided which protrudes in a first axial direction, and at least one second loop region (7b) is provided which protrudes in a second axial direction which is opposite to the first axial direction.

4. The method according to claim 3, It is characterized in that The first loop region (7a) and the second loop region (7b) are each axially positioned within a winding space (21) of the stator (1), wherein the winding space (21) is axially delimited by the axially outermost tangential regions of the partial coil (4) and the connecting wire (6).

5. The method according to any one of claims 1 to 4, It is characterized in that The at least one loop region (7a, 7b) is formed by means of a mechanical forming tool (8).

6. The method according to any one of claims 1 to 5, It is characterized in that The coil carrier (2) is received in the holding device (9) as a linear structure (10) in the second step and / or the coil carrier (2) is brought into an annular structure (11) after the second step and before the third step.

7. A stator (1) for an electric machine, the stator having regularly spaced teeth (3), the stator comprising a plurality of partial coils (4) wound around the teeth (3), in, The partial coils (4) are connected to each other in groups by means of connecting wires (6) close to the end surface (5) of the stator (1), characterized in that at least one connecting wire (6) partially forms a loop area (7a) protruding axially inwardly.

8. The stator (1) according to claim 7, It is characterized in that At least one connecting wire (6) partially forms a loop region (7b) protruding axially outward.

9. The stator (1) according to claim 8, It is characterized in that The stator (1) has a winding space (21), which is delimited in the axial direction by the partial coil (4) and the connecting wire (6), wherein the axial boundary of the winding space (21) is defined by the tangential extension area of ​​the partial coil (4) and the connecting wire (6) which is located axially most outer relative to the stator (1), Furthermore, the loop regions (7a, 7b) are axially formed within the winding space (21) and do not exceed the axial boundaries of the winding space.

10. The stator (1) according to any one of claims 7 to 9, It is characterized in that The stator (1) is produced according to the method according to any one of claims 1 to 6.

11. A forming tool (8) for forming a loop region (7a, 7b) on a stator coil, the forming tool having two forming jaws (12, 13) which are movable relative to each other in a predetermined deformation direction (20), in, Two first pin-shaped projections (14) are arranged on the first forming jaw (12), the two first projections are spaced apart from each other and each extend transversely to the deformation direction (20), and a second pin-shaped projection (15) is arranged on the second forming jaw (13), the second projection also extending transversely to the deformation direction (20), wherein the forming jaws (12, 13) are designed so that the second projection (15) can be pushed into and out of the intermediate space (16) between the two first projections (14).

12. The forming tool (8) according to claim 7, It is characterized in that The projections (14, 15) extend parallel to one another and / or perpendicular to the deformation direction (20).

13. The forming tool (8) according to claim 7 or 8, It is characterized in that The first molded clamping jaw (12) has a guide groove (17) between the first protrusions (14), and a guide protrusion (18) designed to be complementary to the guide groove can be inserted into the guide groove (17).

14. The forming tool (8) according to any one of claims 7 to 9, It is characterized in that The shaped jaws (12, 13) directly form the jaws of a pair of pliers (19).

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