Method for producing a winding package of an electric motor

Abstract

The present invention relates to a method for producing a winding package of an electric motor, comprising the steps of: providing a sheet metal strip along a feed direction, punching grooves alternately into the opposite longitudinal sides of the sheet metal strip, and winding the punched sheet metal strip to form the winding package, wherein the punching of the opposite grooves is carried out by means of two independently operable punching tools.

Description

State of the art

[0001] The present invention relates to a method for producing a winding package of an electric motor, as well as a device for producing a winding package of an electric motor.

[0002] A variety of manufacturing methods for winding packs for electric motors are known. Such winding packs are typically used as part of a stator or rotor of the electric motor, with windings made of electrically conductive wires wound around sections of the winding packs, for example, at least partially within slots. The slots are often created by punching the sheet metal parts. Winding packs made from a punched and wound sheet metal strip are also known. Furthermore, various types of windings are known, such as so-called plug-in windings. Conventional manufacturing processes are often complex and can only allow for limited fill factors for the winding packs to be produced. Disclosure of the invention

[0003] The inventive method with the features of claim 1 is characterized by the fact that windings can be produced with low effort and particularly high dimensional accuracy. Furthermore, a high fill factor and simple assembly and electrical contacting are possible. This is achieved according to the invention by a method for producing a winding package, in particular a preformed coil, of an electric motor, comprising the steps: - Providing a sheet metal strip along a feed direction, - Punching grooves alternately into the opposite long sides of the sheet metal strip, and - Winding the punched sheet metal strip into the winding package.

[0004] The opposite grooves are punched using two independently operable punching tools.

[0005] In particular, a sheet metal strip is considered to be a strip made of an electrically conductive material, preferably a metal, which is thin in the thickness direction and has a large longitudinal extent along the feed direction.

[0006] The sheet metal strip is preferably made of aluminum or an aluminum alloy, or of copper or a copper alloy.

[0007] Preferably, the grooves are created such that they each extend parallel to a transverse direction orthogonal to the feed direction, in particular alternately extending from one of the two opposite longitudinal sides of the sheet metal strip. In particular, each groove is thus open on one side along the transverse direction. This produces a punched sheet metal strip with a meandering shape.

[0008] The stamped sheet metal strip is wound around a winding axis orthogonal to the feed direction, which is particularly parallel to the transverse direction. In particular, the sheet metal strip is wound spirally into a substantially cylindrical winding stack, with individual layers of the sheet metal strip lying one above the other in the radial direction.

[0009] In particular, the two punching tools can be operated independently of each other, at least in terms of time and / or relative arrangement to each other.

[0010] Preferably, the sheet metal strip can be moved along the feed direction during the process, wherein the movement is initiated, for example, by the sheet metal strip being wound into the winding package by means of a winding device and / or being actively fed by means of a separate feed device.

[0011] Preferably, the sheet metal strip can be moved continuously along the feed direction during the execution of the method, or alternatively preferably discontinuously, for example in such a way that the sheet metal strip is stationary during punching.

[0012] In other words, the process uses two punching tools to create a meandering geometry of the sheet metal strip, which is then wound into the winding package. The two punching tools can be operated independently of each other, for example, to ensure an optimal relative arrangement of the grooves to be produced.

[0013] The process offers the advantage of enabling the production of winding packages with optimally arranged slots by winding a sheet metal strip using a simple and cost-effective device with minimal effort. The punching of the slots can be optimally and flexibly adjusted to ensure particularly tight tolerances regarding positioning accuracy in the winding package. This also enables a high fill factor, simple assembly, and simple and precise electrical contacting of the windings. This also enables the production of a particularly efficient electric motor.

[0014] The subclaims show preferred developments of the invention.

[0015] The fed sheet metal strip is preferably designed to widen counter to the feed direction. This means that a maximum outer dimension of the sheet metal strip along a direction orthogonal to the feed direction increases in a direction opposite to the feed direction. As a result, an axial dimension of the wound winding package increases from radially inward to radially outward. In particular, the sheet metal strip is designed such that, in the wound winding package, a radially innermost layer has the smallest axial length, i.e., the smallest winding overhang, and in particular the radially outermost layer has the greatest axial length, i.e., the greatest winding overhang. This makes it possible to provide a winding package with a particularly advantageous geometry. In particular, a reduction in the number of winding overhangs is achieved.This makes it possible to provide a winding package for an electric motor that is particularly compact and at the same time particularly efficient in operation.

[0016] Particularly preferably, the fed sheet metal strip is designed to widen continuously, in particular linearly, in the opposite direction to the feed direction. This means that an outer contour of the sheet metal strip is defined by a straight line. In particular, this makes it possible to provide a conically widening geometry of the sheet metal strip. This enables particularly simple and cost-effective production of the winding package.

[0017] Preferably, the fed sheet metal strip is designed to widen symmetrically in the opposite direction to the feed direction. This means that, with respect to the feed direction, both outer geometries of the sheet metal strip widen symmetrically. This allows for a simple and reliable reduction in the number of winding heads while allowing for simple and cost-effective production of the sheet metal strip.

[0018] Preferably, the slots are punched in such a way that increasing distances are formed between each two adjacent slots along a direction opposite to the feed direction. In particular, the punching is carried out in such a way that the increasing distances form aligned recesses on the wound winding package, in particular in the radial direction. This means that the increase in diameter during winding of the winding package is taken into account by increasing distances between the slots. This produces a winding package which has a plurality of recesses distributed over the circumference running in the radial direction, which in particular each completely penetrate the winding package in the radial direction, wherein the recesses are formed by the radially aligned grooves of the wound sheet metal strip.

[0019] Particularly preferably, the slots are punched by sequential punching with adjusted time offsets using the two punching tools. A time offset is considered, in particular, to be the time interval between a first punching operation with the first punching tool and a second punching operation with the second punching tool. This means that the distances between the slots, which increase counter to the feed direction, are made possible by increasing the time offset during sequential punching using the two punching tools. Thus, the winding package can be manufactured with a particularly precise geometry in a simple and efficient manner.

[0020] Preferably, the two punching tools are arranged at a predefined, fixed distance from each other. In particular, the predefined, fixed distance corresponds to a minimum conductor width of the winding package. The minimum conductor width is considered to be the smallest distance between two adjacent recesses provided on the radially innermost circumference of the winding package.

[0021] Preferably, the grooves are punched by adjusting the distance between the punching tools. This means that the distances between the grooves, which increase in the direction opposite to the feed direction, are created by continuously increasing the distance between the two punching tools. This allows the grooves to be created with particular precision and with a high degree of time efficiency.

[0022] Preferably, the grooves are punched by simultaneously operating both punching tools. This means that both punching tools always punch simultaneously. This allows for particularly simple and cost-effective control of the punching tools. Furthermore, particularly time-efficient punching can be achieved.

[0023] More preferably, the slots are punched using three punching tools. In particular, a third punching tool is used for each of the slots, with a first punching tool and a second punching tool preferably being used alternately for every second slot. In particular, the third punching tool is provided for a transversely central region of the respective slots, with the first punching tool and the second punching tool each punching the opposite outer regions of the slots. This makes it possible to provide an alternative device with which the winding package can be manufactured particularly precisely and efficiently.

[0024] The method preferably further comprises the step of producing a winding, in particular in the form of a plug-in winding. Particularly preferably, the plug-in winding can be designed as a continuous plug-in winding.

[0025] Furthermore, the invention leads to a device for producing a winding package of an electric motor, comprising at least two punching tools, a winding device, and a control device. The winding device is configured for winding a sheet metal strip. In particular, grooves can be punched into the sheet metal strip using the two punching tools. The control device is configured to actuate the punching tools and the winding device and to carry out the described method. In particular, the control device can actuate the punching tools in such a way that time offsets between the respective punching processes of the two punching tools and / or a tool spacing of the punching tools are adjusted in a controlled manner. Short description of the drawings

[0026] Embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawing: Fig. 1 a simplified schematic view of an apparatus for producing a winding package of an electric motor, with which a method according to a first embodiment of the invention is carried out, Fig. 2 a simplified schematic detailed view of the device of the Fig. 1 during the implementation of the method of the first embodiment, Fig. 3 a further simplified schematic detailed view of the implementation of the method of the first embodiment, Fig. 4 a simplified schematic detailed view of the implementation of a method according to a second embodiment of the invention, Fig. 5 a simplified schematic detailed view of the implementation of a method according to a third embodiment of the invention, Fig. 6 a simplified schematic detailed view of the implementation of a method according to a fourth embodiment of the invention, and Fig. 7 a simplified schematic perspective view of a rotor with a winding package produced by the method according to the invention. Embodiments of the invention

[0027] Preferably, all identical components, elements and / or units in all figures are provided with the same reference numerals.

[0028] Fig. Figure 1 shows a simplified schematic view of an apparatus 100 for producing a winding package 10. A method according to a first embodiment of the invention is carried out with the apparatus 100. Details of the apparatus and the method of the first embodiment are shown in the Fig. 2 and Fig. 3 shown.

[0029] The method according to the invention is used to produce winding packages 10 for use in electric motors. Such electric motors are suitable, for example, as drive motors for vehicles, such as motor vehicles or electric bicycles.

[0030] The winding packages 10 produced by the method are then used as windings in a rotor core 60, as for example in Fig. 7 shown. Fig. 7 shows the rotor laminated core 60, which comprises a rotor core 70 and the winding core 10.

[0031] The device 100 comprises a punching device 40, which comprises a first punching tool 3 and a second punching tool 4. Furthermore, the device 100 comprises a winding device 7, which is configured for winding a sheet metal strip 1, and a control device 50, which is configured for actuating the punching device 40 and the winding device 7.

[0032] In the method, a sheet metal strip 1, which is made of aluminum or copper, for example, is fed along a feed direction 15. In particular, the movement of the sheet metal strip 1 along the feed direction 10 occurs by winding by means of the winding device 7 around a winding axis 70 orthogonal to the feed direction 15.

[0033] For example, the movement of the sheet metal strip 1 along the feed direction 10 can take place continuously at a constant speed, or alternatively discontinuously, wherein the sheet metal strip 1 is preferably held in position during punching.

[0034] In particular, the sheet metal strip 1 extends in its width direction in a transverse direction 16 orthogonal to the feed direction 15 and parallel to the winding axis 70. In the transverse direction 16, the sheet metal strip 1 is limited by its outer longitudinal sides 12 (cf. Fig. 2).

[0035] Before winding around the winding axis 70, the sheet metal strip 1 is moved straight along the feed direction 50. In this process, grooves 2 are alternately punched into the two opposite longitudinal sides 12 of the sheet metal strip 1 using the two punching tools 3, 4. This means that 16 outwardly open grooves 2 are alternately punched into the sheet metal strip 1 in the transverse direction. This creates a meandering shape of the sheet metal strip 1. The grooves 2 have a groove width 19 predetermined by the respective punching tool 3, 4. The groove width 19 is identical for all grooves 19.

[0036] In particular, the punching tools 3, 4 have rounded edges with predetermined minimum radii 25. This prevents corners on the sheet metal strip 1 at the grooves 2 and on the outside, which in particular reduces the risk of voltage flashover.

[0037] In the method according to the first embodiment, the two punching tools 3, 4 are operated independently of each other, such that sequential punching occurs with adjusted time offsets. In detail, the punching tools 3, 4 are operated such that increasing distances 11 are formed between the grooves 2 in a direction opposite to the feed direction 15 (see Fig. 3). These distances 11 each correspond to a conductor width 17 of the punched sheet metal strip 1.

[0038] The distances 11 between the slots 2 are continuously increased such that the resulting wound winding package 10 has a plurality of recesses 20 distributed around the circumference, which penetrate the winding package 10 in the radial direction and are formed by the radially aligned slots 2.

[0039] In the first embodiment, the increasing distances 11 or conductor widths 17 are achieved by continuously increasing the time offsets between punching with the two punching tools 3, 4, whereby the two punching tools 3, 4 are always arranged at a constant, fixed tool distance 30 from each other. This tool distance 30 corresponds to the smallest conductor width 17.

[0040] In particular, during the first punching of the first slots 2 of the winding package 10, the two punching tools 3, 4 can punch simultaneously in order to produce the first slots 2 at the distance 11 of the smallest conductor width 17.

[0041] The method enables the production of winding packages 10 with optimally arranged slots 2 by winding the sheet metal strip 1 using a simple and cost-effective device 100 with little effort. The punching of the slots 2 can be optimally and flexibly adapted to provide particularly low tolerances with regard to the positioning accuracy of the recesses 20 in the winding package 10. In particular, this also enables a high fill factor, simple assembly, and simple and precise electrical contacting of the windings.

[0042] Fig. Figure 4 shows a simplified schematic detailed view of the implementation of a method according to a second embodiment of the invention. The second embodiment essentially corresponds to the first embodiment of the Fig. 1 to 3, with the difference that the sheet metal strip 1 is designed alternatively. The fed sheet metal strip 1 is designed to widen in the opposite direction to the feed direction 15.

[0043] In detail, the sheet metal strip 1 is designed to widen in such a way that an envelope 28 of the two longitudinal sides 12 widens linearly and symmetrically on each side. As a result, an axial outer dimension of the wound winding package 10 increases from radially inside to radially outside. This enables an advantageous geometry of the manufactured winding package 10 by reducing the number of winding heads. Thus, a particularly compact and simultaneously efficient winding package 10 for an electric motor can be produced.

[0044] Fig. Figure 5 shows a simplified schematic detailed view of the implementation of a method according to a third embodiment of the invention. The third embodiment essentially corresponds to the first embodiment of the Fig. 1 to 3, with the difference of an alternative generation of the increasing distances 11 between the adjacent grooves 2. In the third embodiment of the Fig. 5, the increasing distances 11 are created by increasing the tool distance 30 between the two punching tools 3, 4.

[0045] In the third embodiment, the two punching tools 3, 4 are always operated simultaneously. This means that punching is always performed simultaneously with both punching tools 3, 4. This makes it possible to provide a particularly time-efficient method, for example, allowing continuous movement of the sheet metal strip 1 along the feed direction 15 with no or minimal pauses.

[0046] Fig. Figure 6 shows a simplified schematic detailed view of the implementation of a method according to a fourth embodiment of the invention. The fourth embodiment essentially corresponds to the first embodiment of the Fig. 1 to 3, with the difference of an alternative design of the punching device 40. In the fourth embodiment of the Fig.6, the punching device comprises a total of three punching tools 3, 4, 5. A third punching tool 5 is provided, which punches a central region of the sheet metal strip 1 in the transverse direction 16 for each individual slot 2. The first punching tool 3 and the second punching tool 4 each alternately punch the opposite outer regions of the slots 2. This makes it possible to provide an alternative device 100 with which the winding package 10 can be manufactured particularly precisely and efficiently.

Claims

[1] Method for producing a winding package (10) of an electric motor, comprising the steps: - Providing a sheet metal strip (1) along a feed direction (15), - punching grooves (2) alternately into the opposite longitudinal sides (12) of the sheet metal strip (1), and - Winding the punched sheet metal strip (1) into the winding package (10), - wherein the punching of the opposing grooves (2) is carried out by means of two punching tools (3, 4) which can be operated independently of one another. [2] Method according to claim 1, wherein the supplied sheet metal strip (1) is designed to become wider opposite to the feed direction (15). [3] Method according to claim 2, wherein the supplied sheet metal strip (1) is designed to widen continuously, in particular linearly. [4] Method according to claim 2 or 3, wherein the supplied sheet metal strip (1) is designed to widen symmetrically. [5] Method according to one of the preceding claims, wherein the punching of the grooves (2) is carried out in such a way that increasing distances (11) are formed between each two grooves (2) opposite to the feed direction (15), in particular in such a way that aligned recesses (20) are formed on the wound winding package (10). [6] Method according to claim 5, wherein the punching of the grooves (2) is carried out by sequential punching with adapted time offsets by means of the two punching tools (3, 4). [7] Method according to claim 6, wherein the punching tools (3, 4) are arranged at a fixed tool distance (30) from one another, in particular wherein the tool distance (30) corresponds to a smallest conductor width (17). [8] Method according to claim 5, wherein the punching of the grooves (2) is carried out by adjusting the tool distance (30) between the punching tools (3, 4). [9] Method according to claim 8, wherein the punching of the grooves (2) is carried out by simultaneous actuation of the two punching tools (3, 4). [10] Method according to one of the preceding claims, wherein the punching of the grooves (2) is carried out by means of three punching tools (3, 4, 5), in particular wherein a third punching tool (5) is used for each groove (2). [11] A method according to any one of the preceding claims, further comprising the step of: producing a winding. [12] Device for producing a winding package (10) of an electric motor, comprising: - at least two punching tools (3, 4), - a winding device (7) which is designed to wind a sheet metal strip (1), and - a control device (50) which is arranged to actuate the punching tools (3, 4) and the winding device (7), - wherein the device is designed to carry out the method according to one of the preceding claims.

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