Electric motor with connection element for a winding of a stator on a printed circuit board with at least two insulation displacement contacts.

Abstract

An electric motor with a rotor rotatably mounted about an axis of rotation and a stator comprising a stator core and coils wound on the stator core, wherein the windings are formed from a winding wire with winding wire ends (5), and wherein the winding wire ends (5) are electrically contacted at their end faces with a printed circuit board (3) by means of connection elements (1), wherein the connection elements (1) each have at least two insulation displacement contacts (4) into which each of the winding wire ends (5) of a stator winding is received, wherein each connection element (1) has a single electrical connection to the printed circuit board (3), characterized in that the connection element (1) has a base body (8) which, in the assembled state, lies with its underside in contact with the printed circuit board (3), and that the at least two insulation displacement contacts (4) each have a clamping slot (7).which is oriented perpendicular to the underside of the base body (8) and wherein the clamping slots (7) are formed by means of spaced-apart legs (11, 12, 13) extending from the base body (8), wherein at least two legs (11, 12) are resiliently designed.

Description

The present invention relates to an electric motor having the features of the preamble of claim 1. Electric motors consist of a rotor connected to a motor shaft and rotatably mounted in a housing. The rotor is equipped with permanent magnets. A stator, which carries a number of windings on an iron core, is arranged within or around the rotor. With appropriate control, the windings generate a magnetic field that drives the rotor to rotate. The windings are typically three-phase and are therefore provided with three electrical terminals for connection to a control unit (ECU). This connection is conventionally made by contacting the windings with a printed circuit board (PCB) on which the ECU is mounted. This contacting is achieved using soldered or welded connections or insulation displacement connectors (IDCs). German patent application GB 2 058 485 A describes a connecting element with two legs. Each leg comprises insulation displacement contacts for electrical connection. The document AT 5 450 E also shows electrical connection elements with multiple insulation displacement contacts. US patent 4,084,877 A describes an electrical connector comprising three adjacent contacts extending from a base. When an insulated electrical conductor is inserted between two of these contacts, the insulation is compressed or severed, thereby establishing the desired electrical contact. Electric motors with connection elements are known, for example, from the German patent application DE 10 2004 027 380 A1 and the patent application EP 2 212 985 B1. German patent application DE 10 2011 121 943 A1 also discloses control electronics for a brushless electric motor of a motor vehicle. The control electronics comprise at least one insulation displacement contact mounted on a printed circuit board, which has an insulation displacement terminal for receiving a phase wire of a field winding of the electric motor. The object of the present invention is to provide an electric motor with a connection element for an electrical connection of a winding of a stator to a printed circuit board, which enables the simplest and most durable contact possible. This problem is solved by an electric motor having the features of claim 1. Furthermore, an electric motor is provided with a rotor rotatably mounted about an axis of rotation and with a stator comprising a stator core and coils wound on the stator core. The windings are formed from a winding wire with winding wire ends, and the winding wire ends are electrically contacted at their end faces to a printed circuit board by means of connection elements. Each connection element has at least two insulation displacement contacts, into each of which a single winding wire end of a stator winding is received. Each connection element has a single electrical connection to the printed circuit board. The connection element combines the winding wire ends in a single electrical connection to the printed circuit board, thereby saving space and reducing the number of electrical connections. The electrical connection is preferably a soldered connection or a single press-fit contact. The connection element has a base body whose underside, when mounted, is in contact with the printed circuit board. The at least two insulation displacement contacts each have a clamping slot oriented perpendicular to the underside of the base body. This makes it particularly easy to insert the winding wire ends into the slots. The slots are preferably aligned parallel to each other. The clamping slots are formed by means of spaced-apart legs extending from the base body, with at least two legs being resilient. In one embodiment, two clamping slots are formed by means of three legs, with a central leg being part of both insulation displacement contacts. This central leg is preferably rigid. However, it is also possible for each insulation displacement contact to have two legs, and for all legs to be spaced apart from each other. It is advantageous if the winding ends of a motor phase are assigned to the at least two insulation displacement contacts of a terminal element. Since no insulation is required between the contacts, the wire diameter of the winding wires can be increased, thereby increasing the current-carrying capacity per motor phase. Preferably, only two insulation displacement contacts are provided per terminal element. Two preferred embodiments of the invention are explained in more detail below with reference to the drawings. Identical or functionally equivalent components are designated with the same reference numerals in the figures. Figure 1 shows a longitudinal section through a connection element with two insulation displacement contacts, and Figure 2 shows a longitudinal section through another connection element with two insulation displacement contacts. The connection elements 1 shown in Fig. 1 and Fig. 2 have in common that they have a single press-fit contact 2 for electrical contacting with a printed circuit board 3 and two insulation displacement contacts 4 for receiving an end section 5 of a winding wire 6 of a stator of an electric motor. The insulation displacement contacts (IDCs) 4 have clamping slots 7. A sharp contact in the clamping slots 7 cuts the insulation of the winding wire ends 5 and achieves electrical contact with the wire core of the winding wire 6. Since only one press-fit contact 2 is provided, the design is significantly more compact compared to using two separate connection elements, each with a press-fit contact. Each terminal slot 7 accommodates only one winding wire end 5. This has the advantage that a defined gap geometry exists before the winding wire end 5 is pressed in. Furthermore, this results in improved contact reliability, which is maintained even after aging and vibration loading of the connection element 1. The two end sections 5, contacted in a terminal element 1, are assigned to one phase of the electric motor. Since no insulation is required between the contacts, the wire diameter of the winding wires can be increased, thereby increasing the current-carrying capacity per motor phase. As shown in Fig. 1, the connecting element 1 preferably has a flat base body 8 with two opposing end faces 9, 10. When attached to the printed circuit board 3, a first end face 10 rests on the board over a large area. The press-fit contact 2 is formed on this first end face 10. The two insulation displacement contacts 4 are arranged on the second end face 9, each formed by two legs 11, 12 extending away from the base body 10. A clamping slot 7 is arranged between each pair of legs 11, 12. The legs 11, 12 are all spaced apart from each other. The clamping slot 7 is arranged approximately perpendicular to the surface of the printed circuit board 3 and to the first end face 10 of the base body 8. A wire 6 is inserted into each insulation displacement contact 4 or clamping slot 7. The insertion direction is shown schematically by the arrows 13.The legs 11, 12 are preferably elastically designed to enable a permanent and stable compression of the winding wire 6 in the clamping slot 7. The clamping slot 7 has a sharp contact area on the surface of the legs inside, which strips the insulation from the winding wire 6 when it is pressed in and when it passes by. The clamping slots 7 have an insertion and pressing chamfer 14. Figure 2 shows a further embodiment. In contrast to the embodiment shown in Figure 1, only three spaced-apart legs 11, 12, 13 are arranged on the second end face 9 of the base body 8. The two insulation displacement contacts 4 share the middle leg 13. This middle leg 13, which lies between the two outer legs 11, 12 and thus forms two clamping slots 7, is rigidly designed. To enable permanent crimping of the winding wire ends into the clamping slots 7, the two outer legs 11, 12 are resiliently designed. The clamping slots 7 also have insertion and insertion chamfers 14. In another embodiment, depending on the application, it may also be provided that the connecting element has more than two insulation displacement contacts. The connecting element generally does not have a press-fit contact, but is soldered directly onto the circuit board. The winding wire is preferably made of enamelled copper wire.

Claims

An electric motor with a rotor rotatably mounted about an axis of rotation and a stator comprising a stator core and coils wound on the stator core, wherein the windings are formed from a winding wire with winding wire ends (5), and wherein the winding wire ends (5) are electrically contacted at their end faces with a printed circuit board (3) by means of connection elements (1), wherein the connection elements (1) each have at least two insulation displacement contacts (4) into which each of the winding wire ends (5) of a stator winding is received, wherein each connection element (1) has a single electrical connection to the printed circuit board (3), characterized in that the connection element (1) has a base body (8) which, in the assembled state, lies with its underside in contact with the printed circuit board (3), and that the at least two insulation displacement contacts (4) each have a clamping slot (7).which is oriented perpendicular to the underside of the base body (8) and wherein the clamping slots (7) are formed by means of spaced-apart legs (11, 12, 13) extending from the base body (8), wherein at least two legs (11, 12) are resiliently designed. Electric motor according to claim 1, characterized in that the electrical connection is a soldered connection or a single press-fit contact (2). Electric motor according to claim 1 or 2, characterized in that two clamping slots (7) are formed by means of three legs (11, 12, 13), wherein a middle leg (13) is part of both insulation displacement contacts (4). Electric motor according to claim 3, characterized in that the middle leg (13) is rigid. Electric motor according to one of the preceding claims, characterized in that the winding ends (5) received in the at least two insulation displacement contacts (4) of a connection element (1) are assigned to a motor phase.

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