Contact device for a stator of an electric motor

Abstract

The invention relates to a contact device (10) for a stator (4) of an electric motor (2), comprising an interconnection ring (22) placed or placeable on the end face of a stator core (14), and a plurality of bus bars (28) for interconnecting coil ends (20) of a stator winding (6) with a plurality of phase terminals (8), wherein at least one bus bar (28) has an axially directed contact lug (26), and wherein the contact lug (26) has a crimp contour (29) for contact with a respectively associated coil end (20).

Description

[0001] Page 1 2022432 WO Description Contact device for a stator of an electric motor The invention relates to a contact device for a stator of an electric motor, comprising an interconnection ring which is placed or can be placed on the end face of a stator core, and a number of busbars for interconnecting coil ends of a stator winding with a number of phase connections, wherein at least one busbar has an axially directed contact lug. The invention further relates to a stator, a method for producing a stator, and an electric motor. Motor vehicles nowadays usually have a number of adjustment parts, for example a seat adjustment, an actuatable lock, a window lifter and / or an adjustable sliding roof, which can be moved between different adjustment positions by means of a respectively assigned electromotive adjustment drive.A brushless electric motor, in particular a three-phase electric machine, generally has a stator with a number of stator teeth, arranged in a star shape, for example, which carry an electrical rotating field or stator winding in the form of individual coils, which in turn are wound from an insulated wire. The coils are assigned to individual strands or phases by their coil ends (winding wire ends), are interconnected in a predetermined manner, and are led to phase connections for energizing the rotating field winding. The phases of a three-phase current feeding the rotating field winding and the associated rotating field are referred to as (motor) phases. In a figurative sense (page 2), this also includes the stator coils (phase winding) assigned to each such phase, with the associated connecting lines (phase end).In the case of a brushless electric motor as a three-phase AC machine, the stator has three phases and thus at least three phase conductors or phase windings, each of which is supplied with electrical current in a phase-shifted manner to generate a rotating magnetic field in which a rotor or armature, usually equipped with permanent magnets, rotates. The phase ends of the phase windings are connected to motor electronics to control the electric motor. The coils of the rotating field winding are connected in a star or delta connection and electrically contacted with the three phase terminals. To guide and connect the coil ends, contact devices in the form of interconnection systems or switching units are commonly used. These are mounted on the front of the stator or a stator core.Such contact devices serve in particular to electrically connect the coil ends of the winding wire sections forming the coil windings, so that individual coil ends are electrically short-circuited with one another, and thus the coil or phase windings can be energized in series. Such contact devices often have a number of integrated or overmolded conductor tracks or busbars as connecting conductors for connecting or contacting the coil ends. During assembly of the electric motor or stator, the coil ends are contacted with the busbars, so that coil windings assigned to a common phase are short-circuited with one another via the contact device. The contact between the coil ends and the busbars is usually made by means of a material connection, for example by soldering or welding.Page 3 A "material bond" or a "material bond" between at least two interconnected parts is understood here and below in particular to mean that the interconnected parts are held together at their contact surfaces by material union or cross-linking (e.g. due to atomic or molecular bonding forces), possibly with the action of an additive. Conventionally, for example, brazing is used, which is comparatively insensitive to positional tolerances or wire misalignment of the coil ends, since an electrode presses a coil end to be soldered against a contact or welding lug of the busbar, thereby creating a brazed connection. The disadvantage of brazing is that it requires additional brazing materials, such as Silfos, which are cost-intensive and necessitate an additional process in the manufacture of the stator.Other joining techniques, such as laser welding, are comparatively sensitive to positional and positioning tolerances. Therefore, such joining methods require comparatively high positioning accuracy when positioning the coil end on the busbar. In particular, direct (point) contact of the insulated coil end on the busbar is necessary. Furthermore, during laser welding, no plastic components may be arranged in the area of ​​the contact point, as these could melt, thereby limiting the positioning freedom on the contact device. The invention is based on the object of specifying a particularly suitable contact device for a stator. In particular, simple and reliable contacting of the coil ends is to be achieved.The invention is further based on the object of specifying a particularly suitable stator and a particularly suitable method as well as a particularly suitable electric motor. Page 4 The contact device according to the invention is intended for a stator of an electric motor and is suitable and designed therefor. The contact device has an interconnection ring which is placed or can be placed on the end face of a stator core and by means of which the coil or winding ends of a wound stator core are interconnected to form a multi-phase stator winding. For this purpose, the interconnection ring has a number of busbars for interconnecting coil ends of the stator winding with a number of phase connections. The phase connections form the interface to motor electronics or a motor control unit, via which three-phase current is fed in during motor operation.The busbars, which are particularly designed as stamped and bent parts, are embedded or integrated into the interconnection ring, for example. The busbars are preferably overmolded as an insert with the interconnection ring designed as an injection-molded part, wherein the busbars are at least partially exposed in the contact area with the coil ends. The contact areas of the busbars with the coil ends are each designed as an axially directed contact lug, each having, according to the invention, a crimp contour for non-positive electrical (crimp) contact with the respectively assigned coil end. The coil ends are therefore not welded or soldered to the contact lugs in a material-locking manner, but rather crimped positively and / or non-positively without a material connection. This results in a particularly suitable contact device.Crimp contacting enables cost- and energy-efficient wiring and contacting of the coil ends or the stator winding to the phases and with the phase connections. Furthermore, this eliminates the need for cost-intensive additional and soldering materials for the wiring and contacting process. Here and in the following, “axial” or an “axial direction” is understood to mean a direction parallel (coaxial) to the axis of rotation of the electric motor, i.e., perpendicular to the end faces of the stator. Accordingly, here and in the following, “radial” or a “radial direction” is understood to mean a direction oriented perpendicular (transverse) to the axis of rotation of the electric motor along a radius of the stator or electric motor.“Tangential” or a “tangential direction” is understood here and below to mean, in particular, a direction along the circumference of the stator or the electric motor (circumferential direction, azimuthal direction), i.e., a direction perpendicular to the axial direction and the radial direction. The conjunction “and / or” is understood here and below to mean that the features linked by means of this conjunction can be designed both together and as alternatives to one another. A “positive connection” or a “positive connection” between at least two interconnected parts is understood here and below to mean, in particular, that the interconnected parts are held together at least in one direction by a direct interlocking of contours of the parts themselves or by an indirect interlocking via an additional connecting part.The "blocking" of mutual movement in this direction is therefore due to the shape. A "positive connection" or a "positive connection" between at least two interconnected parts is understood here and below in particular to mean that the interconnected parts are prevented from sliding against each other due to a frictional force acting between them. If a "connecting force" causing this frictional force is missing (this means the force that presses the parts against each other, for example a screw force or the weight itself), the positive connection cannot be maintained and can therefore be released. In an advantageous embodiment, the contact lug has an axial crimp slot which divides the contact lug into two crimp legs.The crimp slot serves as a contact or clamping slot for the coil end to be contacted, which is crimped to the crimp legs for crimp contacting. This allows for structurally simple crimp contacting using the contact lug. In a suitable further development, the crimp slot opens into a wire receptacle which has a wider diameter than the crimp slot. The wire receptacle is adapted to the outer circumference of the coil end to be contacted. In the case of a coil end designed as a round wire, the wire receptacle is correspondingly designed as a circular through-opening for the contact lug. The coil end is pressed axially along the crimp slot into the wire receptacle, whereby the reduced diameter of the crimp slot creates an axially positive fit for the coil end within the wire receptacle.The stator according to the invention is intended for an electric motor and is suitable and configured therefor. The stator has a stator core, designed for example as a stamped laminated core, with a number of radial stator teeth, each wound or equipped with a coil. The coils each have two axially oriented coil ends. A contact device as described above for contacting and connecting the coils or coil ends to form a multi-phase rotating field or stator winding is placed axially on the end face of the stator core. The contact device or its connection ring has a number of axial through-openings corresponding to the number of coil ends, through which the coil ends to be connected are guided to a respective contact lug. According to the invention, the coil ends are crimped or crimp-contacted using the crimp contours of the contact lugs.This results in a particularly suitable stator which is particularly cost-effective to manufacture. In a preferred embodiment, the or each coil end to be contacted is bent radially for crimp contacting. Preferably, the coil end is pivoted during bending such that the coil end is pressed into the wire receptacle through the axial crimp slot. Suitably, the coil end is inserted axially in a form-fitting manner into the wire receptacle of the contact lug. In an expedient embodiment, it is provided that for crimp contacting, two crimp legs of the contact lug are pressed radially and / or tangentially onto the coil end. The terms radial and / or tangential refer in particular to a longitudinal direction of the approximately cylindrical coil end. In other words, the crimp legs are pressed from the outside onto the outer circumference of the coil end.This ensures reliable and operationally safe contacting of the coil end. The method according to the invention is intended for producing a stator as described above, and is suitable and designed for this purpose. A stator core, a number of coils or coil wires, and a contact device as described above are provided. According to the method, a number of radial stator teeth of the stator core are equipped or wound with coils, wherein the coil ends of the coils are aligned in an axially oriented manner. The contact device is then placed on the end face of the stator core in such a way that at least one coil end is guided through a through-opening in the interconnection ring to a contact lug, and wherein the coil end is crimp-connected to the contact lug. This realizes a particularly suitable method for producing a stator.The coil ends of the stator to be contacted are axially oriented, with the interconnection ring having axial through-openings for the coil ends, which are arranged adjacent to the contact lugs. When fitted, the coil ends are thus oriented substantially parallel to the contact lugs. Preferably, the coil ends are bent approximately radially and pressed axially into a wire receptacle through a crimping slot in the contact lug, with two crimping legs of the contact lug being pressed from the outside onto the respective coil end. This enables reliable and structurally simple contacting of the coil ends. The electric motor according to the invention is intended for a motor vehicle and is suitable and configured therefor. The electric motor has a stator as described above. An exemplary embodiment of the invention is explained in more detail below with reference to a drawing: Fig.Fig. 1 shows a schematic and simplified representation of an electric motor of a motor vehicle, Fig. 2 shows a perspective representation of a contact device of a stator, Fig. 3 shows a perspective exploded view of the stator and the contact device, Fig. 4 shows a perspective representation of a contact lug of the contact device, Fig. 5 shows a perspective representation of the contact lug with a contacted coil end, and Fig. 6 shows a perspective representation of a crimp contact of the coil end. Corresponding parts and sizes are always provided with the same reference numerals in all figures. Fig. 1 shows a schematic and highly simplified representation of an electric motor 2 of a motor vehicle. The electric motor 2 has a stator 4 with a multi-phase rotating field or stator winding 6, which is connected to motor electronics 12 for current supply by means of phase connections (phase contacts) 8 of a contact device 10 (Fig. 2, Fig. 3).When energized, the rotating field winding 6 generates a rotating magnetic field which drives a rotor (not shown in detail) of the electric motor 2. In the exemplary embodiment shown, the stator winding 6 is in particular three-phase with three (motor) phases U, V, W. Each phase U, V, W is formed from a phase winding which is essentially formed by connecting at least one coil of the stator winding. In this exemplary embodiment, the phases U, V, W are connected to one another in a delta connection. Fig. 2 shows a perspective view of the contact device (switching unit) 10 for the stator 4. Fig. 3 shows the stator 4 and the contact device 10 in a partially disassembled state. As can be seen in particular in Fig. 3, the contact device 10 is placed on the front side of the stator 4 or on a stator core 14 in the assembled state.The stator core 14 of the stator 4 comprises, for example, twelve inwardly directed stator teeth, onto which the stator or rotating field winding 6 of the electric motor 2 is applied. The coil windings are wound in particular as (individual) coils 16, for example, on insulating winding supports or coil supports 18, and are placed with these on the stator teeth of the stator core. Each of the frame-like winding supports carries a coil 16 as part of the stator winding 6. The coils 16 each have two approximately axially directed coil ends 20. The coils 16, coil supports 18, and coil ends 20 are provided with reference numerals in the figures merely as examples. The coil ends 20 of the (individual) coils 16 are connected to the stator winding 6, which in this exemplary embodiment is three-phase, by means of the contact device 10 placed on the end face of the stator 4.During electromotive operation, the energized windings of the stator winding 6 generate a stator-side magnetic field, which interacts with permanent magnets of a rotor of the brushless electric motor 2 rotating around the central stator or motor axis. The contact device 10 has an annular interconnection ring 22. The coil ends 20 of the coils 16 are guided through axial through-openings 24 and contacted on the upper side of the interconnection ring 22 with contact lugs 26 for interconnection. The through-openings 24 and contact lugs 26 are provided with reference numerals in the figures merely as examples. The contact device 10 has a number of busbars or conductor tracks 28 as connecting conductors for interconnecting the coil ends 20 or the contact lugs 26 with the phase terminals 8.The approximately axially directed contact lugs 26 are formed integrally, i.e., monolithically, on the busbars 28 as contact points for contacting or electrically conductive connection with the respectively assigned coil end 20. In particular, the contact lugs 26 are designed as angled rail ends of the busbars 28. The busbars 28 are preferably embedded in the interconnection ring 22 or overmolded therewith, with essentially only the contact lugs 26 protruding. The contact lugs 26 are designed in particular as crimp lugs for a material-free crimp connection with the in particular stripped coil ends 20. The busbars 28 and contact lugs 26 are designed, for example, as common stamped and bent parts made of a copper material. Figures 4 to 6 each show a detail of a contact lug 26 and a through-opening 24. As shown, for example, in Fig.As can be seen in Figure 4, the contact lug 26 has a crimp contour 29 with an axial crimp slot 30, which divides the contact lug 26 into two crimp legs 32 in a fork-like manner. The crimp slot 30 is widened towards the free ends of the crimp legs 32, so that an insertion bevel 34 is formed for easier insertion of the coil end 20. Opposite the insertion bevel 34, a circular through-opening is made in the contact lug 26 as a wire receptacle 36. The wire receptacle 36 has a wider diameter than the crimp slot 32. Preferably, the diameter of the wire receptacle 36 corresponds to the diameter of the (stripped) coil end 20. Page 11 As shown, for example, in Figures 5 and 6, the axial coil end 20 is bent approximately radially and pressed axially through the crimp slot 32 into the wire receptacle 36 via the insertion bevel 34.In this case, the coil end 20 sits axially and positively in the wire receptacle 36 (Fig. 5). The crimping legs 32 are then pressed from the outside against the outer circumference of the coil end 20 seated in the wire receptacle 36 by means of a pressing tool 38 and are thus crimped or crimp-contacted by means of the crimping contour 29. The claimed invention is not limited to the exemplary embodiments described above. Rather, other variants of the invention can also be derived therefrom by a person skilled in the art within the scope of the disclosed claims without departing from the subject matter of the claimed invention. In particular, all individual features described in connection with the various exemplary embodiments can also be combined in other ways within the scope of the disclosed claims without departing from the subject matter of the claimed invention.

[0002] Page 12 List of reference symbols 2 Electric motor 4 Stator 6 Stator / rotating field winding 8 Phase connection 10 Contact device 12 Motor electronics 14 Stator package 16 Coil 18 Coil carrier 20 Coil end 22 Connection ring 24 Through opening 26 Contact lug 28 Busbar 29 Crimp contour 30 Crimp slot 32 Crimp leg 34 Lead-in chamfer 36 Through opening 38 Crimping tool

Claims

Page 13 Claims 1. Contact device (10) for a stator (4) of an electric motor (2), comprising: - a connecting ring (22) mounted or attachable to the end face of a stator core (14), and - a number of busbars (28) for connecting coil ends (20) of a stator winding (6) with a number of phase terminals (8), - wherein at least one busbar (28) has an axially oriented contact lug (26), and - wherein the contact lug (26) has a crimp contour (29) for contacting a respective associated coil end (20).

2. Contact device (10) according to claim 1, characterized in that the contact lug (26) has an axial crimp slot (30) which divides the contact lug (26) section by section into two crimp legs (32). 3.Contact device (10) according to claim 2, characterized in that the crimp slot (32) opens into a wire receptacle (36) which has a diameter wider than that of the crimp slot (32).

4. Stator (4) for an electric motor (2), comprising a stator core (14) with a number of radial stator teeth, each of which is equipped with a coil (16), and a contact device (10) according to any one of claims 1 to 3 for connecting the coils (16) to form a stator winding (6), wherein the coils (16) have two axially oriented coil ends (20), wherein at least one coil end (20) is guided through a through-opening (24) of the connecting ring (22) to a contact lug (26), and wherein the coil end (20) is crimp-contacted by means of a crimp contour (29) of the contact lug (26). Page 14 5. Stator (4) according to claim 4, characterized in that the coil end (20) is radially bent for crimp contact.

6. Stator (4) according to claim 4 or 5, characterized in that the coil end (20) is axially positively inserted into a wire receptacle (34) of the contact lug (26).

7. Stator (4) according to any one of claims 4 to 6, characterized in that two crimp legs (32) of the contact lug (26) are pressed onto the coil end (20) for crimp contact. 8.Method for manufacturing a stator (4) according to one of claims 4 to 7, - wherein a number of radial stator teeth of a stator stack (14) are fitted with coils (16) whose coil ends (20) are axially oriented, - wherein a contact device (10) according to one of claims 1 to 3 is placed on the stator stack (14) such that at least one coil end (20) is guided through a feedthrough opening (24) of the interconnection ring (22) to a contact lug (26), and - wherein the coil end (20) is crimp-contacted with the contact lug (26).

9. Method according to claim 8, characterized in that - the coil end (20) is radially bent and axially pressed into a wire receptacle (36) through a crimp slot (30) of the contact flag (26), and - two crimp legs (32) of the contact flag (26) are pressed onto the coil end (20). Page 15 10. Electric motor (2) for a motor vehicle, comprising a stator (4) according to one of claims 4 to 7.

Images