METHOD FOR MANUFACTURING A STATOR

Description

[0001] The invention relates to a method for manufacturing a stator for an electric motor.

[0002] German patent application DE 10 2016 204 935 A1 discloses a connection plate for the stator of an electric machine. The connection plate connects the stator's electrical windings to a connector for the power supply. The connection plate has conductor elements with circumferentially extending, flattened cross-section connecting sections that link the windings. These connecting sections are overmolded with an annular plastic body that insulates the conductor elements from each other.

[0003] German patent application DE 10 2016 210 927 A1 discloses a stator for an electric machine, which has winding heads of electrical windings arranged in a ring on one end face of a laminated core. A connection unit serves to electrically connect the winding ends to the electrical phase conductors of a voltage source. The connection unit has a support ring made of an electrically insulating material, which is arranged radially around the outside of the winding heads by means of fixing elements. The support ring holds each electrically conductive connection element for connecting one of the phase conductors.

[0004] German patent application DE 10 2016 222 611 A1 discloses a device for connecting the wiring of an electrical machine's stator. The device comprises a base body with a bottom surface, the underside of which can be placed onto a stator. The base body has at least one positioning means for positioning at least one electrical conductor of the stator's wiring. The positioning means has an insertion opening. The insertion opening is located on the underside of the base body, so that when the device is placed onto the stator, the at least one electrical conductor is inserted through the insertion opening into the positioning means.The positioning means has a guide section and a connection section, wherein the positioning means is designed such that the at least one electrical conductor is guided into the connection section by means of the guide section when the base body is placed on the stator.

[0005] German patent application DE 10 2016 224 526 A1 discloses a stator of an electric machine consisting of a stator lamination stack. Each phase comprises at least one coil having a first and a second coil end. A contact device is mounted on the end face of the stator lamination stack for contacting the coils. A routing element and a connecting element mounted on it serve to connect the coil ends to phase terminals on a stator end face. The coil ends project vertically through through-holes in the routing element and are guided at a radial angle along a guide groove in the routing element. The guide grooves each have a constriction in the axial direction, which secures the coil end guided in the groove against axial slippage.

[0006] German patent application DE 10 2017 216 084 A1 discloses a stator for an electric machine, comprising a stator body and radial stator teeth for receiving coils of an electrical winding. An insulating lamella with pockets for insulation displacement connectors (IDCs) is provided on one end face of the stator body. The coils, wound with winding wire, are inserted into the pockets. A terminal plate has ring-shaped conductors, each with several IDCs that engage axially in the pockets to electrically contact the winding wire. The terminal plate is made of plastic.

[0007] German utility model DE 20 2014 003 844 U1 discloses a circuit arrangement comprising at least three copper profiles. Each copper profile is bent into a ring around a bending axis. The copper profiles are insulated with a layer of lacquer, which is removed at predetermined locations. At these locations, spaced-apart connection areas with at least one flat surface for contacting the ends of coil wires are formed.

[0008] German utility model DE 20 2014 010 565 U1 discloses a stator of an electric motor with a multiphase, in particular three-phase, stator winding. The coils are provided with an end-face arranged circular arc-shaped connection unit, the connection unit comprising a second set of busbars, each with a third set of winding and / or contact elements for the coils. The winding and / or contact elements are joined as separate stamped elements with a stamped strip to form the respective busbar.

[0009] For the production of the windings, wave and hairpin windings are pre-bent from individual strands of insulating wire (copper or aluminum alloys) using winding templates or freehand, and then inserted into the stator lamination stack of the electric motor. Depending on the number of phases (two or more) of the electric motor, the individual strands are then connected to the individual phases, the neutral point (star conductor), and to each other in the direction of current flow to generate the rotating magnetic field of the stator. The connection sequence, the number of winding wires, and other parameters, such as wire gauge, the number of stator slots, and the number of pole pairs, depend on the design of the electric motor. The individual winding wires are connected to the phases (power supply via, for example, busbars), the star conductor, and to each other using connecting elements, such as welding, according to the connection sequence.The individual connections for the wiring are, for example, welded, soldered or similar processes in several work steps.

[0010] The object of the invention is therefore to provide a method for manufacturing a stator for an electric motor that reduces manufacturing costs, the manufacturing process, and the development effort for the stator. This involves a fully automated manufacturing process with the fewest possible work steps. At the same time, this manufacturing process, the design of the circuitry, and the configuration of the production equipment should be scalable to different electric motors (and sizes).

[0011] This problem is solved by a method for manufacturing a stator for an electric motor, comprising the features of claim 1.

[0012] A stator for an electric motor produced according to the inventive method comprises a winding head of a stator winding, which has a plurality of winding ends. A connection element comprises several busbars and a star busbar. Several contact points of the busbars and contact points of the star busbar project axially from the busbars of the stator. The connection element surrounds the winding ends of the winding head. A bending comb is positioned on the connection element. The winding ends are bent over the bending comb to the contact points of the connection element. The winding ends thereby make electrical contact with the contact points.

[0013] The design of the stator is advantageous because it reduces manufacturing costs, the manufacturing process, and the development effort. Specifically for stators with particularly efficient winding technologies, such as wave windings and hairpin windings, the stator according to the invention enables a fully scalable and automated manufacturing process. Furthermore, the minimal axial design of the stator is advantageous.

[0014] The multiple busbars and the star busbar of the interconnection element are overmolded with an insulating material for electrical insulation. The contact points of the individual busbars protrude beyond the insulating material in the axial direction. This overmolding advantageously reduces positional tolerances between the busbars and the star busbar.

[0015] At least one pair of centering pins is formed on the connection element. The corresponding bending comb can be fixed to the centering pins by means of through-holes formed on the connection element.

[0016] The winding ends are welded, clamped or soldered to the contact points for a permanent electrical connection.

[0017] An attachment sits on the bending comb. This attachment contains insulating material to provide electrical insulation for the winding ends connected to the contact points. The bending comb with attachment, which remains on the connection element after potting, offers the advantage of electrical insulation for both the contact points and the winding ends.

[0018] The winding ends are welded, clamped, or soldered to the contact points for a permanent electrical connection.

[0019] A fitting sits on the bending comb and encloses an insulating material that provides electrical insulation between the contact points and the winding ends connected to them. The bending comb and the fitting remain on the stator after being potted with insulating material.

[0020] The inventive method for manufacturing a stator for an electric motor is defined by claim 1 and comprises the step of placing and positioning a connecting element on the stator such that the connecting element surrounds a plurality of winding ends at the winding head of the stator winding. The connecting element itself comprises several busbars and a star busbar, from which several contact points of the busbars and several contact points of the star busbar project in the axial direction of the stator. The winding ends are bent to the contact points of the busbars or to the contact points of the star busbar of the connecting element by means of a bending comb positioned on the connecting element. The contact points of the busbars or the contact points of the star busbar are thereby electrically contacted. A bending comb is positioned on the connecting element.The winding ends are bent over the bending comb and electrically connected to the contact points of the busbars and the star busbar of the interconnection element. An attachment is placed on the bending comb, into which insulating material is inserted to provide electrical insulation between the contact points and the electrically connected winding ends.

[0021] The method according to the invention has the advantage that a scalable, standardized manufacturing process and production facilities are possible. Likewise, full automation of production can be achieved, thereby reducing the number of assembly steps. This, in turn, leads to a reduction in manufacturing errors.

[0022] According to the invention, all winding ends are simultaneously bent over the bending comb using a device. This device has several rollers that move radially outwards from the inside over the bending comb. During this process, the winding ends are folded along a bending radius and into grooves. In addition to bending the winding ends, the bending comb also serves as insulation from the weld points (contact points) to the winding head and thus remains attached to the stator or electric motor.

[0023] The bent winding ends of the stator winding head are welded, clamped or soldered to the contact points of the interconnection element to provide a permanent electrical connection.

[0024] Each bending frame can be automatically placed and positioned on the clamping element. For this purpose, the clamping element has several centering pins that engage in openings formed on the bending comb.

[0025] An attachment is placed on the bending comb. Insulating material is placed inside the attachment and the bending comb to achieve electrical insulation of the winding ends that are electrically connected to the contact points.

[0026] According to the invention, the following fully automated manufacturing process can be defined for contacting and insulating the contact points of the busbars and the star busbar with the winding ends of the stator winding head. First, the connection element is placed and positioned on the stator winding head. The connection element can, for example, be bonded to the stator winding head. Next, the bending comb is placed onto the connection element. Using a specially designed device, all winding ends (wires) are simultaneously bent over the bending comb. The device is designed as a roller tool.

[0027] The connection of the contact points to the respective winding ends can be achieved, for example, radially from the outside by laser welding the individual contact points. Before inserting the attachment (potting frame), a contact test is performed on all weld points. Finally, an insulating material is poured into the attachment and thus into the bending frame, thereby achieving an insulating potting of all weld points (contact points) and the winding ends.

[0028] The insulation material can be a synthetic resin or a silicone to ensure complete insulation between the angled winding ends (wires). This insulation significantly reduces air and creepage distances, thereby further reducing the stator's installation space. To prevent the liquid insulation material from running between the ribs of the bending comb during pouring, the attachment (potting frame) is designed as a negative mold of the bending comb in this area. The provided centering pins, like those used for the bending comb itself, are used to position the attachment during assembly.

[0029] The invention and its advantages will now be explained in more detail with reference to the accompanying drawings, using exemplary embodiments, without thereby limiting the invention to the embodiment shown. The proportions in the figures do not always correspond to the actual proportions, as some shapes are simplified and others are enlarged in relation to other elements for better illustration. Figure 1 shows a perspective view of a connection element for the winding ends of a stator. Figure 2 shows a perspective view of the basic structure of the stator connection with the connection element, where the connection element is not potted. Figure 3 shows a perspective view of the basic structure of the stator connection with the connection element, where the connection element is potted. Figure 4 shows a perspective detail view of the connection of the stator winding ends with the connection element, where the connection element is not potted. Figure 5 shows a perspective detail view of the connection of the stator winding ends with the connection element, where the connection element is potted. Figure 6 shows a sectional view of the connection element in conjunction with the stator winding head and the resulting contact.Figure 7 shows a perspective view of a bending comb for making electrical contact between the winding ends and the contact points of the connecting element. Figure 8 shows an enlarged view of the connecting element with the bending comb in use. Figure 9 shows an enlarged detail view of the bending comb. Figure 10 shows an enlarged detail view of the end of the bending comb. Figure 11 shows a schematic view of the connecting element connected to the winding head and a schematic representation of a tool for folding over the winding ends. Figure 12 shows a schematic side view of the device for folding over the winding ends of the stator winding head. Figure 13 shows a perspective view of an attachment for potting the ready-to-use winding ends. Figure 14 shows a perspective view of the attachment that surrounds the area of ​​the connecting element to be potted.Figure 15 shows an enlarged partial view of the attachment on the connection element. Figure 16 shows a perspective view of the attachment with potting compound already poured into it. Figure 17 shows an enlarged partial view of the attachment on the connection element with the potting compound poured into it. Figure 18 shows a perspective view of the individual elements required for the electrical connection of the winding ends at the winding head.

[0030] Identical reference numerals are used for identical or equivalently functioning elements of the invention. Furthermore, for the sake of clarity, only those reference numerals necessary for describing the respective figure are shown in the individual figures. The figures merely illustrate embodiments of the invention, without, however, limiting the invention to the illustrated embodiments.

[0031] Figure 1shows a perspective view of a wiring element 3 for winding ends 8 (see Fig. 4 or 5 ) at the winding head 2 (see Fig. 2) of a stator 1. The interconnection element 3 comprises several busbars 41, 42, and 43 and a star busbar 40. The several busbars 41, 42, and 43 and the star busbar 40 of the interconnection element 3 are overmolded with an insulating material 12. The several busbars 41, 42, and 43 and the star busbar 40 are, for example, overmolded with plastic as insulating material 12. This ensures electrical insulation between the individual busbars 41, 42, and 43 and the star busbar 40 and a fixed positioning of these relative to each other. The contact points 71, 72, and 73 of the individual busbars 41, 42, and 43, the contact points 41 of the star busbar 40, and the connection points 51 project beyond the insulating material 12 in axial direction A.In the embodiment shown here, the individual busbars 4 1 , 4 2 and 4 3 (three phases) each have corresponding power connections 11 1 , 11 2 and 11 3, which can also extend in axial direction A from the corresponding busbar 4 1 , 4 2 and 4 3 or the star busbar 40.

[0032] Figure 2 shows a perspective view of the basic structure of the circuit of stator 1 with circuit element 3, where the circuit element 3 is not potted. Figure 3 Figure 1 shows a perspective view of the basic structure of the stator 1 circuit with circuit element 3, where circuit element 3 is potted. The illustrations of the Figures 2 and 3 The multitude of winding ends 8 are already connected to the contact points 71, 72 and 73 (see Fig. 1 ) of the individual busbars 41, 42 and 43 and the contact points 41 (see Fig. 1The ends of the star busbar 40 are bent into their final position and thus contact the contact points 71, 72, and 73 or 41. By bending the winding ends 8 at the winding head 2 in radial direction B (outwards), a small axial profile A of the connection of the winding ends 8 can be achieved. In the encapsulated connection element 3, the busbars 41, 42, and 43 and the star busbar 40 are completely embedded in the insulating material 12. The connection element 3 is located at the winding head 2 of the stator 1. Only the current connections 111, 112, and 113 for the individual busbars 41, 42, and 43 are accessible. The contact points 71, 72, and 73 are also visible (see figure). Fig. 1 ) of the individual busbars 41, 42 and 43 and the contact points 41 (see Fig. 1 ) the star rail 40 bent winding ends 8.

[0033] Figure 4shows a perspective detail view of the connection of the winding ends 8 of the stator 1 at the connection element 3, where the connection element 3 is not potted. Figure 5 Figure 1 shows a perspective detail view of the connection of the winding ends 8 of the stator 1 with connection element 3, where the connection element 3 is potted. The detailed representations of the Figures 4 and 5 The multitude of winding ends 8 are already connected to the contact points 71, 72 and 73 (see Fig. 1 ) of the individual busbars 41, 42 and 43 and the contact points 41 (see Fig. 1 ) of the star rail 40 bent into the end position and thus contact the contact points 71, 72 and 73 or 41. In the connecting element 3, which is sheathed with the insulating material 12, only the bent winding ends 8 are still visible, which contact the contact points 71, 72 and 73 (see Fig. 1) of the individual busbars 41, 42 and 43, the contact points 41 (see Fig. 1 ) the star rail 40 and the connection point 51 (see Fig. 1 ) contact.

[0034] Figure 6 Figure 1 shows a sectional view of the interconnection element 3 in conjunction with the winding head 2 of the stator 1 and the resulting contacts. The winding ends 8 are already bent into their final position onto the contact points 71, 72, and 73, the contact points 41, and the connection points 51, thus making electrical contact. By bending the winding ends 8 outwards in the radial direction B, a low profile in the axial direction A of the interconnection can be achieved. According to the invention, variable scaling (axial / radial) is possible by adjusting the busbars 41, 42, and 43, and the star busbar 40. Therefore, the basic interconnection structure remains constant for design and production and can be implemented quickly.

[0035] At the same time, the wiring can be scaled to different requirements and motors and adapted to varying installation space requirements. The busbars 41, 42 and 43, and the star busbar 40 are surrounded by the insulating material 12 and are thus able to be fixed to each other and electrically isolated from each other.

[0036] Figure 7 shows a perspective view of a bending comb 5 for making the electrical contact between the winding ends 8 and the contact points 71, 72 and 73, 41 and the connection points 51 (see Fig. 6 The bending comb 5 has a plurality of grooves 13 and comb ribs 14 separating the grooves 13. The free ends 16 of the bending comb 5 each have an opening 9. The opening 9 serves to receive a centering pin 15 (see Fig. 8 ) of the interconnection element 3 (see Fig. 8 ).

[0037] Figure 8Figure 1 shows an enlarged view of the connection element 3 with the bending comb 5 used. The bending comb 5 is positioned on the connection element 3 via centering pins 15. This ensures precise alignment of the winding ends 8 with the connection element 3. Simultaneously, the winding ends 8 are separated and aligned by the comb ribs 14.

[0038] Figure 9 Figure 1 shows an enlarged detail view of the central part of the bending comb 5. The upper grooves 13 on the bending comb 5 are arranged on a radius 5R. The arrangement of the grooves 13 on the radius 5R causes the individual winding ends 8 to spread out towards the respective contact points 71, 72, 73 and 41, as well as the connection points 51 (see Figure 1). Fig. 6 ) for carrying out the bending of the winding ends 8. As already described in the description to Fig. 8As mentioned, the comb ribs 14 serve to spatially separate and electrically insulate the winding ends 8 from each other.

[0039] Figure 10 Figure 1 shows an enlarged detail view of a free end 16 of the bending comb 5. The opening 9 is formed at the free end, which is for the correct positioning of the bending comb 5 on the connecting element 3 (see Figure 2). Fig. 8 .) serves this purpose. The assembly of the bending comb 5 on the connection element 3 is carried out automatically, for example, via a robot arm (not shown).

[0040] Figure 11 shows a schematic view of the interconnection element 3 connected to the winding head 2 and the schematic representation of a device 20 for flipping the winding ends 8. Figure 12Figure 20 shows a schematic side view of the device for folding the winding ends 8 of the winding head 2 of the stator 1. The device 20 has several rollers 22 which are rotatably mounted and guided on a guide 24. The rollers 22 can be brought into contact with the winding ends 8 and press on them. The rollers 22 act on the winding ends 8 in radial direction B, causing them to bend by a radius 28 along the respective bending edge 29 of each groove 13 of the bending comb 5 in the direction of the respective contact points 71, 72, 73 and 41, as well as the connection points 51 (see Figure 28). Fig. 6 ) are bent over. The bending, carried out by means of the rollers 22 over the bending comb 5, is performed from the inside in radial direction B to the outside. The winding ends 8 are folded over along the bending radius 28 and the grooves 13 (see Fig. 11 ).

[0041] Figure 13shows a perspective view of an attachment 10 for potting the ready-to-use winding ends 8 in the bending comb 4. Figure 14 shows a perspective view of the attachment 10, which surrounds the area of ​​the bending comb 5 on the connecting element 3 to be cast. Figure 15 An enlarged partial view of the attachment 10 on the bending comb 5 of the connection element 3 is shown. The attachment 10 defines a potting frame 18 which is filled with a potting compound 19 (see Fig. 16 or 17) surrounds the area to be filled. At each free end 17, the potting frame 18 also has an opening 9 through which the attachment 10 can be mounted on the centering pin 15 of the connecting element 3. The potting frame 18 of the attachment 10 has a negative mold of the bending comb 5, so that a positive fit is ensured between the potting frame 18 of the attachment 15 and the bending comb 5. This positive fit ensures that no material leaks out during potting. As the Fig. 14 As can be seen, the attachment 10 is positioned in relation to the bending comb 5 by the centering pins 15 of the connecting element 3. Figure 15 This illustrates the attachment of the attachment 10 to the bending comb 5. The attachment 10 also has an opening 9 at its free end 17, through which the attachment 10 can be positioned in relation to the bending comb 5.

[0042] Figure 16shows a perspective view of the attachment 10 on the bending comb 5, in which an insulating material 12 has already been filled as a potting compound 19. Figure 17 Figure 1 shows an enlarged partial view of the attachment 10 on the bending comb 5, which sits on the connecting element 3. As already described in the section on the Fig. 14 and 15 As mentioned, the attachment 10 is also positioned by means of the centering pins 15 of the connecting element 3. The insulating material 12 filled into the attachment 10 and the bending comb 5 surrounds and covers the contact points 71, 72, 73 and 41 as well as the connection points 51 (see Fig. 6 ). This provides protection against environmental influences and electrical insulation of the contact points 7 1 , 7 2 7 3 and 41 as well as the connection points 51 and also the bent winding ends 8.

[0043] Figure 18Figure 1 shows a perspective view of the individual elements (bending comb 5, extension 10, and connection element 3) required for the electrical connection of the winding ends 8 at the winding head 2. First, the connection element 3, which connects several busbars 41, 42, 43, and a star busbar 40 (see Figure 2), is shown. Fig. 1 ) comprises, positioned in axial direction A on the winding head 2 of the stator winding 6 of the stator 1. The interconnection element 3 surrounds a plurality of winding ends 8 on the winding head 2 (see Fig. 6Before the contact points 71, 72, 73, and 41, as well as the connection points 51, make contact with the winding ends 8, a bending comb 5 is positioned on the connection element 3. Only then are the winding ends 8 bent over the bending comb 5 to electrically contact the contact points 71, 72, 73, and 41, as well as the connection points 51 of the busbars 41, 42, and 43 of the connection element 3. Finally, the attachment 10 is placed onto the bending comb 5. Insulating material 12 is then inserted into the attachment 10 and the bending comb 5. The bending comb 5 and the attachment 10 remain on the stator 1 and also contribute to the insulation of the contact points 71, 72, 73, and 41, as well as the connection points 51. The potted insulating material 12 provides electrical insulation between the contact points 7 1 , 7 2 7 3 and 41 as well as the connection points 51 and the bent winding ends 8. Reference symbol list

[0044] 1 Stator 2 Winding head 3 Interconnect element 4 1 First bus bar 4 2 Second bus bar 4 3 Third bus bar 5 Bending comb 5 Radius 6 Stator winding 7 1 Contact points 7 2 Contact points 7 3 Contact points 8 Winding end 9 Holeout 10 Attachment 11 1 Power connection 11 2 Power connection 11 3 Power connection 12 Insulation material 13 Groove 14 Comb rib 15 Centering pin 16 Free end 17 Free end 18 Potting frame 19 Potting 20 Setup 22 Roller 24 Guide 28 Bending radius 29 Bending edge 40 Star rail 41 Star rail contact point 51 Connection point Aaxial direction Bilateral direction

Claims

1. A method for producing a stator (1) for an electric motor, having the following steps: - placing and positioning of a switching element (3), which comprises multiple bus bars (41, 42, 43) and a star rail (40), from which multiple contact points (71, 72, 73) of the bus bars (41, 42, 43) and multiple contact points (41) of the star rail (40) protrude in the axial direction (A) of the stator (1), on the stator (1) in such a way that the switching element (3) surrounds a plurality of winding ends (8) on the winding head (2) of the stator winding (6) of the stator (1); - positioning of a bending comb (5) on the switching element (3); - bending of the winding ends (8) over the bending comb (5) and making electric contact with the contact points (71, 72, 73) of the bus bars (41, 42, 43) and the contact points (41) of the star rail (40) of the switching element (3); and - placing of an attachment (10) on the bending comb (5), into which an insulation material (12) is introduced, so that an electrical insulation is achieved between the contact points (71, 72, 73) and the contact points (41) and the electrically connected winding ends (8), wherein all winding ends (8) are bent simultaneously over the bending comb (5) using a device (20), wherein the device (20) has multiple rollers (22), which are moved from the inside in a radial direction (B) outwards over the bending comb (5), and in the process folds the winding ends (8) along a bending radius (28) and into grooves (13).

2. The method according to claim 1, wherein the bent winding ends (8) of the winding head (2) of the stator winding (6) are welded, clamped or soldered to the contact points (71, 72, 73, 41) of the switching element (3) in order to provide a permanent electrical connection.

3. The method according to any one of the preceding claims 1 to 2, wherein each bending frame (5) is placed and positioned on the switching element (3) in an automated manner, wherein for this purpose multiple centering pins (15) are formed on the switching element (3) which engage in openings (9) formed on the bending comb (5).

4. The method according to claim 3, wherein an attachment (10) is placed on the bending comb (5) and an insulating material (12) is introduced into the attachment (10) in order to achieve an electrical insulation of the winding ends (8) electrically connected to the contact points (71, 72, 73, 41).