Method for electrically contacting at least one enamelled copper wire with a component of an electric motor, generator, sensor or electromagnet by means of electrical contacts formed at the ends of the enamelled copper wire and additional potting

Abstract

Method for electrically contacting at least one enamelled copper wire, which forms a winding supported by a first component (1), with a second component of an electric motor, generator, sensor or electromagnet comprising the following steps: - Strengthening at least one wire end (2) by mechanical processing and / or surface treatment, a) Forming at least one wire end (2) of the at least one enamelled copper wire into an electrical contact (3, 6, 8), wherein the electrical contact (3, 8) is a plug contact, b) Positioning the electrical plug contact (3, 6, 8) in a forming process, wherein the forming compound (4) formed in the forming process at least partially surrounds the first component (1) and the at least one wire end (2), c) Contacting the electrical plug contact (3,6,8) with the second component.

Description

[0001] The present invention relates to a method for electrically contacting at least one copper enamelled wire with a component of an electric motor, generator, sensor or electromagnet and an electric motor having the features of the preamble of claim 5.

[0002] When electrically contacting copper enamelled wire arranged in windings with a component of an electric motor, generator, sensor or electromagnet, it is known to use contact plugs or to solder or weld the wire ends.

[0003] Various drive devices are known from patent applications DE 10 2015 217 441 A1, DE 10 2018 201 331 A1, JP 2011 114 979 A, ​​DE 11 2015 002 671 T5, and JP 200 007 8804 A. EP 1 973 200 A1 discloses a connector for electrical connections. Patent application DE 699 06 915 T2 discloses a vehicle AC generator. Patent application US 2019 / 0 245 406 A1 discloses a stator overmolded with injection molding. Furthermore, patent application US 8 896 170 B2 discloses twisting the wire ends of an armature winding and leading them out as terminals.

[0004] The invention is based on the objective of simplifying and making the contacting process more reliable.

[0005] This problem is solved by a method for electrically contacting at least one copper enamelled wire with a component of an electric motor, generator, sensor or electromagnet with the features of claim 1 and by an electric motor with the features of claim 5.

[0006] The term "copper enamel wire" refers to a wire made of a copper alloy that is surrounded by an electrically insulating layer of enamel.

[0007] Accordingly, a method for electrically contacting at least one enamelled copper wire, which forms a winding supported by a first component, with a second component of an electric motor, generator, sensor or electromagnet is provided with the following steps: a) Forming at least one wire end of the at least one enamelled copper wire into an electrical contact, b) Positioning the electrical contact in a forming process, wherein the forming compound formed in the forming process at least partially surrounds the first component and the at least one wire end, c) Contacting the electrical contact with the second component.

[0008] The contacting process is therefore particularly simple and space-saving. Furthermore, heat can be efficiently dissipated via the molding compound formed during the forming process. In addition, the forming process preferentially heats the winding wire, which also removes the wire's insulation, thus eliminating the need for stripping.

[0009] The forming process can be injection molding, classic potting, vacuum potting or transfer molding.

[0010] The electrical contact is a plug connector. Preferably, this plug connector is a press-fit connector. However, a round connector, flat connector, or other shape can also be used, which is inserted into the second component for electrical contact.

[0011] At least one wire end is hardened by mechanical work hardening, in particular twisting or twisting, and / or by surface treatment to ensure a reliable electrical connection with the second component. If both work hardening methods are used, it is advantageous to cold-form the coated wire ends to achieve the necessary hardness and spring stiffness. This is preferably achieved by cold work hardening through torsion, followed by the formation and / or stamping of a press-fit contour.

[0012] In one embodiment, the method for electrically contacting an armature winding of an armature with a commutator of a brushed electric motor is designed, wherein the armature winding is formed by means of at least one copper enamelled wire, the wire end of which is formed into an electrical contact in step a) and in step b) the armature with the wire end is at least partially surrounded by the molding compound and in step c) the electrical contact is contacted with the commutator.

[0013] To accumulate material for forming the electrical contact, it is advantageous to fold back the winding wire end and thus use twice the wire cross-section for forming.

[0014] In another embodiment, the method for electrically contacting a stator of an electric motor with a printed circuit board is designed, wherein the stator has a stator core and coils made of enamelled copper wire wound on the stator core, and in step a) the at least one wire end belonging to a common phase is formed into an electrical contact, and in step b) the electrical contact is connected to the stator, wherein the forming compound formed in the forming process at least partially surrounds the at least one wire end and the stator, and in step c) the electrical contact is contacted with the printed circuit board.

[0015] This offers the advantage that a separate electrical connection in the form of a busbar unit is no longer necessary.

[0016] Depending on the number of slots and winding configuration, the winding wire ends can belong to a common phase. If two winding wire ends belong to the same phase, they are preferably twisted together around a longitudinal axis, forming a common electrical contact that extends longitudinally along the stator.

[0017] If only one winding wire end is provided per phase, it is preferably twisted around a longitudinal axis and forms an electrical contact that extends in the longitudinal direction.

[0018] Preferably, in process step b) at least two longitudinally extending guide pins are formed on the top side of the stator, which in process step c) serve to center the circuit board on the top side of the stator.

[0019] Furthermore, an electric motor is provided comprising a first component which carries windings made of a copper enamelled wire with wire ends and a second component which is electrically contacted with the wire ends of the windings, wherein at least one wire end is formed into an electrical contact which contacts the second component, wherein the electrical contact is held in its position on the first component by means of a forming process.

[0020] The advantages mentioned above result. The electrical contact is preferably designed as described above.

[0021] In one embodiment, the electric motor has a commutator with a longitudinally extending through-hole, by means of which the commutator is fixed to an armature shaft of the electric motor in a rotationally fixed manner, and an armature body which is supported by the armature shaft, wherein the windings made of enameled copper wire are arranged on the armature body. The electrical contact makes electrical contact between the windings and the commutator, and the electrical contact is held in its position on the armature body containing the windings by means of the forming process.

[0022] In another embodiment, the electric motor - a rotor which is mounted to rotate about an axis of rotation, - a stator, wherein the stator has a stator core and coils wound on the stator core comprising the windings, and - a printed circuit board wherein at least one wire end of each phase is formed into an electrical contact which contacts the printed circuit board, wherein the electrical contact is held in its position on the stator by means of a forming process.

[0023] It is generally advantageous if the electrical contacts protrude from the molding compound formed during the molding process. Sealing during the molding process preferably occurs within the tool itself or through geometries at the winding wire end.

[0024] In the case of the brushless electric motor, the molding compound formed during the molding process preferably completely surrounds the stator surface, except for the electrical contacts. Furthermore, at least two longitudinally extending guide pins can be formed on the top surface of the stator during the molding process. These guide pins serve to center the printed circuit board on the top surface of the stator.

[0025] Preferred embodiments of the invention are explained in more detail below with reference to the drawings. Similar or functionally equivalent components are designated with the same reference numerals in the figures. The figures show: Fig. 1: A spatial view of a stator of a brushless electric motor, Fig. 2: a detailed view of the Fig. 1 with a connecting element for connecting a winding wire end of the stator to a printed circuit board, Fig. 3: a spatial representation of various connecting elements, as well as Fig. 4: A spatial view of another stator of a brushless electric motor.

[0026] Fig. Figure 1 shows a stator 1, which is part of a brushless DC motor. The stator 1 surrounds a rotor (not shown) and extends coaxially to the rotor's axis of rotation, which, in the assembled state, corresponds to the longitudinal axis of the stator 100. The stator 1 has stator core segments (not shown), around which coils are wound. The coil windings are preferably three-phase, with the windings consisting of a winding wire with winding wire ends 2. The winding wire ends 2 protrude from an end face of the stator 1. In the illustrated case, each winding wire end 2 belongs to a phase. The three winding wire ends 2 are shaped at their ends to form a press-fit contact 3, which is provided for an electrical connection with the printed circuit board. The press-fit contact 3 extends longitudinally.

[0027] The stator 1 is surrounded by molding compound 4 in a molding process. The injection molding process is shown here. The molding compound or potting compound 4 is preferably made of plastic, in particular thermoplastics and thermosets, for example epoxy resin. As shown in Fig. As shown in Figure 1, the top and bottom surfaces of the stator are completely encapsulated. The holding of the windings, in particular the position of the winding wire ends 2, is ensured by the potting compound 4, which surrounds the stator 1.

[0028] Fig. Figure 2 shows a detailed section of stator 1 of the Fig. 1 with a press-fit contact 3. Only the press-fit contact 3 protrudes upwards from the potting compound 4.

[0029] The potting compound allows for better thermal dissipation of the windings' power loss, as the plastic conducts heat better than air. The sealing of the potting compound volume to the press-fit contact 3 can be achieved by the holding tool during the potting process itself or by geometries at the winding wire end. Preferably, a geometry is provided below the press-fit contact 3 that can be securely gripped and enclosed by the holding tool, so that the press-fit contact 3 is not overmolded.

[0030] Press-fit contacts 3 require sufficient spring stiffness for a secure press-fit connection to printed circuit boards or control units. To increase the strength at the winding wire end 2, it can be additionally treated, e.g., by mechanical hardening such as twisting and / or by a suitable surface treatment, in particular by tin plating. If both hardening methods are used, it is advantageous if the tin-coated winding wire ends are cold-formed to achieve the necessary hardness and spring stiffness. Cold hardening is preferably carried out by torsion, followed by stamping of a press-fit contour. The resulting press-fit contact has good springback properties. The temperatures during forming remove the wire insulation, thus eliminating the need for stripping.

[0031] It is also conceivable that the hardness of the plug contact is influenced by the choice of copper wire material or the copper alloy used. The contours of the press-fit contacts can be designed as a pinhole, as shown, or by indentations on both sides.

[0032] To accumulate material for forming the contact, it is advantageous to fold back the winding wire end and thus use the double wire cross-section for forming.

[0033] The positioning of the formed plug contacts takes place in the forming tool.

[0034] The Fig. Figure 3 shows three embodiments of an electrical contact. Depending on the number of slots and the winding scheme of the electric motor, two or three wires can also be connected and formed into an electrical contact. In the Fig. 3 each consists of two winding ends 2 formed into a common electrical contact by plastic deformation, e.g. pressing, compression molding, stamping or the like.

[0035] The first two illustrations on the left show a press-fit connector 3 from two different perspectives. Two winding wire ends 2 are twisted together around a longitudinal axis. At the end, the press-fit connector 3 has a pinhole contour 5 extending longitudinally. The press-fit connector 3 can be inserted into the printed circuit board and establishes an electrical connection with it. No further components or process steps, such as soldering, are necessary.

[0036] The two middle illustrations show a classic knife contour 6 for welding contacts on printed circuit boards. Here, too, two winding wire ends 2 are twisted together around a longitudinal axis and formed at the end into a rectangular, flat contact surface 7. This contact surface 7 can be attached to the printed circuit board by means of a welding process.

[0037] The last two illustrations on the right show a plug connector with a plug pin contour 8. The two winding wire ends 2 are twisted together around a longitudinal axis and formed at their ends into a pin that extends longitudinally. The pin can then be inserted and connected, for example, into a corresponding soldered, preferably spring-loaded, socket on the circuit board. In contrast to the press-fit contour 3, the forming of the winding wire ends 2 is simplified, and the connection is suitable for higher electrical currents.

[0038] Fig. Figure 4 shows another embodiment of a stator 1, wherein, compared to the stator of the Fig. 1. Two additional guide pins 9 were formed on the top side of the stator using an injection molding process. The guide pins 9 serve to center the printed circuit board (PCB) on the top side of the stator. This reduces the tolerance required for positioning the PCB. The guide pins 9 can have a contact shoulder as an axial stop. The guide pins 9 are formed in a single process step during the molding process, together with the overmolding or potting of the winding wire ends 2.

[0039] For positioning the circuit board, a mounting shoulder can also be molded onto the contacts as an axial stop.

[0040] In another embodiment, the previously described type of electrical contact is used in brushed electric motors. These electric motors comprise a commutator which, in the usual manner, has a longitudinal axis with a longitudinally extending through-hole by means of which the commutator is fixed to an armature shaft of the electric motor in a rotationally fixed manner. The armature shaft carries an armature or rotor body with an armature winding consisting of several wire windings inserted into slots in the rotor body. The wire windings are made of enameled copper wire.

[0041] The commutator has a multitude of commutator segments arranged at uniform angular intervals around its circumferential surface, concentrically aligned with a longitudinal axis of the commutator. On the side of the commutator segments facing the armature windings, each segment has a contact element. Conventionally, these contact elements serve to electrically connect the armature windings to the commutator segments, particularly by means of a soldering or welding process. On the side of the commutator segments facing away from the armature windings, the commutator segments interact with brush elements in a known manner.

[0042] According to the invention, the contact elements are connected to the wire windings by means of the formed wire ends. For this purpose, the wire end is formed as described above, creating an electrical contact. Preferably, to increase the material required for forming the electrical contact, the winding wire end is folded back so that twice the wire cross-section is available for forming. Preferably, the electrical contact is a press-fit contact.

[0043] In the forming process, the armature body with the armature windings is surrounded, at least partially, by the molding compound formed during the process. As previously described, the electrical contact remains exposed and protrudes from the molding compound. This electrical contact can then be directly connected to the commutator. Depending on the type of electrical contact, it is possible to weld it to the commutator or, for example, when using press-fit contacts, to insert it into a corresponding contact element.

[0044] This type of electrical contacting allows for the automated contacting or connecting of the wire ends of the armature windings to the contact elements, a process that is safe and reliable. Furthermore, this connection method is particularly space-saving. The described electrical contacting can also be used more generally in generators, sensors, or electromagnets.

Claims

[1] Method for electrically contacting at least one enamelled copper wire forming a winding supported by a first component (1) with a second component of an electric motor, generator, sensor or electromagnet comprising the following steps: - Strengthening at least one wire end (2) by mechanical processing and / or surface treatment, a) Forming at least one wire end (2) of the at least one enamelled copper wire into an electrical contact (3, 6, 8), wherein the electrical contact (3, 8) is a plug contact, b) Positioning the electrical plug contact (3, 6, 8) in a forming process, wherein the forming compound (4) formed in the forming process at least partially surrounds the first component (1) and the at least one wire end (2), c) Contacting the electrical plug contact (3,6,8) with the second component. [2] Method according to claim 1, characterized by, that the method for electrically contacting an armature winding of an armature with a commutator of a brushed electric motor is designed, wherein the armature winding is formed by means of at least one copper enamelled wire, the end of which is formed into an electrical plug contact in step a) and in step b) the armature with the wire end is at least partially surrounded by the molding compound and in step c) the electrical plug contact is contacted with the commutator. [3] Method according to claim 1, characterized by, that the method for electrically contacting a stator (1) of an electric motor with a printed circuit board is designed, wherein the stator (1) has a stator core and coils made of enamelled copper wire wound on the stator core, and in step a) the at least one wire end (2) belonging to a common phase is formed into an electrical plug contact, and in step b) the electrical plug contact is connected to the stator (1), wherein the forming compound (3) formed in the forming process at least partially surrounds the at least one wire end and the stator (1), and in step c) the electrical plug contact is contacted with the printed circuit board. [4] Method according to claim 3, characterized by , that in process step c) at least two longitudinally extending guide pins (14) are formed on the top side of the stator (1), which serve in process step d) to center the circuit board on the top side of the stator (1). [5] Electric motor comprising a first component which carries windings made of enamelled copper wire with wire ends (2) and a second component which is electrically contacted with the wire ends of the windings, characterized by , that at least one wire end (2) is formed into an electrical plug contact (3,6,8), wherein the at least one wire end (2) is hardened by mechanical strengthening and / or by surface treatment and the electrical plug contact contacts the second component, wherein the electrical plug contact (3,6,8) is held in its position on the first component by means of a forming process. [6] Electric motor according to claim 5, characterized by, that the electric motor has a commutator with a longitudinally extending through-bore, by means of which the commutator is fixed to an armature shaft of the electric motor in a rotationally fixed manner, and an armature body which is supported by the armature shaft, wherein the windings made of the copper enameled wire are arranged on the armature body, and the electrical plug contact electrically contacts the windings with the commutator and the electrical plug contact is held in its position on the armature body having the windings by means of the forming process. [7] Electric motor according to claim 5 or 6, characterized by that the electric motor - a rotor which is mounted to rotate about an axis of rotation, - a stator (1), wherein the stator (1) has a stator core and coils wound on the stator core comprising the windings, and - a printed circuit board, wherein at least one wire end (2) of each phase is formed into an electrical plug contact (3,6,8) which contacts the printed circuit board, wherein the electrical plug contact (3,6,8) is held in its position on the stator by means of a forming process. [8] Electric motor according to claim 7, characterized by , that the electrical plug contacts (3,6,8) of all phases protrude from the molding compound (4) formed in the molding process. [9] Electric motor according to claim 7 or 8, characterized by , that the molding compound (4) formed in the molding process completely surrounds the stator surface except for the electrical plug contacts (3,6,8) of all phases. [10] Electric motor according to any one of the preceding claims 7 to 9, characterized by , that at least two longitudinally extending guide pins (9) are formed on the upper side of the stator (1) by forming process. [11] Electric motor according to any one of the preceding claims 5 to 10, characterized by , that two wire ends (2) are twisted together around a longitudinal axis and form the electrical plug contact (3,6,8) which extends in the longitudinal direction. [12] Electric motor according to any one of the preceding claims 5 to 10, characterized by , that a wire end (2) is twisted about a longitudinal axis and forms the electrical plug contact (3,6,8) which extends in the longitudinal direction.

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