Stator of an electrical machine, electrical machine and laying and contact device for an electrical machine

Abstract

Stator (10) of an electrical machine (98), in particular for a motor vehicle, comprising a stator core (25) having a number of stator teeth (16) and a rotating field winding (34) arranged on the stator teeth (16) and comprising a plurality of phases (U, V, W, U', V', W'), each phase (U, V, W, U', V', W') comprising at least one coil (30) having a first and a second coil end (36), and a contact device (38, 38', 38") comprising a laying element (42) placed on the end face of the stator core (25) and a wiring element (44) placed thereon for wiring the coil ends (36) to phase connections (40) on a stator end face, - wherein the coil ends (36) protrude vertically through through-openings (48) of the laying element (42) and are each guided radially and / or tangentially angled along a guide groove (54) of the laying element (42) and are axially contacted and fixed at a contact point (56) of the guide groove (54) by means of a contact element (46) electrically conductively coupled to the interconnection element (44), and - wherein the guide grooves (54) each have a constriction (58) in the axial direction (M), which secures the coil end (36) guided in the guide groove (54) against axial sliding out.

Description

[0001] The invention relates to a stator of an electrical machine, in particular for a motor vehicle, having a stator laminated core which has a number of stator teeth and is provided with a rotating field winding arranged on the stator teeth and comprising several phases, wherein each phase comprises at least one coil which has a first and a second coil end, and with a contact device for contacting and fixing the coil ends. The invention further relates to an electrical machine having such a stator and to a laying and contact device for such an electrical machine. In the following, an electrical machine is understood to mean in particular an electric motor, in particular for a power steering system.

[0002] Many motor vehicles today feature power steering, which reduces the steering effort required to operate the steering wheel when stationary or traveling at low vehicle speeds. Power steering assists the driver in steering by supplementing the steering effort applied by the driver, for example, with a hydraulic system or an electric motor.

[0003] In an electric power steering system (EPS: Electric Power Steering, EPAS: Electric Power Assisted Steering), an electric motor mounted on the steering wheel mechanism (steering column, steering gear) supports and superimposes the vehicle user's steering movements with a generated auxiliary force. Brushless electric motors (brushless direct current motors, BLDC motors) are increasingly being used for such electric motor drives. These motors replace the wear-prone brush elements of a rigid (mechanical) commutator with electronic commutation of the motor current.

[0004] Such a brushless electric motor, as an electric (three-phase) machine, essentially comprises a fixed (stationary) stator with a stator core with a number of stator teeth arranged, for example, in a star shape. The stator teeth carry an electric rotating field winding in the form of individual (stator) coils or coil windings (phase windings), which in turn are wound from an insulating wire (coil wire). The phase windings are assigned to individual (motor) strands or (motor) phases with their coil or phase ends and are interconnected in a predetermined manner.

[0005] In the case of a brushless electric motor as a three-phase 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 via phase connections to control the electric motor. The coil windings of the rotating field winding are interconnected in a specific way using the coil ends. The type of connection of the coil ends is determined by the winding pattern or winding structure of the rotating field winding, with a star connection, a delta connection, or a combination of these being common.

[0006] For guiding and connecting the coil ends, contact devices are commonly used. These are placed on the stator face. Such a contact device comprises, for example, a guide ring and a connecting ring that can be placed on top of it, between which the coil ends to be connected are sandwiched.

[0007] To achieve the most flexible implementation of different winding schemes, it is possible, for example, to design the contact device as a modular assembly, so that a different contact device is mounted on the stator depending on the application and desired wiring. Particularly in applications where single or multiple redundant wiring of the rotating field winding is desired, such a modular contact device disadvantageously requires a comparatively large amount of space (packaging) to reliably represent the wiring geometrically.

[0008] Furthermore, such a contacting device exhibits a comparatively high level of assembly complexity, with the individual manufacturing tolerances of the numerous components adding up. As a result, tolerance requirements regarding the desired optimal positioning on the stator can only be implemented at a relatively high cost.

[0009] EP 2 082 472 B1 discloses an electric motor in which two circular ring-shaped coil carriers arranged on the end faces are mounted on the stator, onto which the coil windings are wound. A hook- or eye-like fastening element is arranged in the stator slot between two adjacent stator teeth, into which a connecting line between the coils mounted on the stator teeth is hooked and electrically connected. The fastening element is coupled to a press-in pin as a contact element, which is pressed into a ring-shaped circuit board (printed circuit board) as a connection ring for contacting. The circuit board has a number of ring lines for connecting the coils to the rotating field winding.

[0010] EP 2 182 616 A2 describes an electric motor with two circular coil carriers mounted on the end face of the stator. One of the coil carriers has a number of positioning aids by means of which a connection ring equipped with a rotational position sensor (rotor position sensor) can be positioned. The positioning aids are designed in the form of radially oriented insulation displacement contacts, with the phase ends of the coils being seated in insulation displacement contacts of the coil carrier and connected by means of a terminal plug of the connection ring.

[0011] DE 199 03 069 A1 discloses a method for contacting the windings of the stator of an electric motor. During assembly, the stator can be pushed axially over the rotor, and the ends of the windings are guided to a contact carrier arranged on the rear end of the windings in the sliding direction. The windings are wound such that the wire ends exit the windings at the rear end, the contact carrier being placed on the end, and the ends are conductively connected to one another on the end by means of an insulation displacement contact.

[0012] DE 10 2010 000 710 A1 describes a bearing plate for an electric motor. The bearing plate has a receptacle for a bearing for supporting a rotor shaft, and the bearing plate is arranged in a housing of an electric motor. The bearing plate further has a current guide configured to connect at least one winding of the stator to a power connection or to another winding of the stator.

[0013] DE 10 2009 044 182 A1 discloses a motor with a cable mounting plate. A connecting cable is attached to the cable mounting plate by means of a groove, with a snap fastener provided for securing the connecting cable in the groove.

[0014] US 2010 / 0259119 A1 discloses a stator for an external rotor motor, which comprises a pair of end plates and a wiring plate. The wiring plate is arranged over one of the end plates, with a fastening device for fastening a welded connection section being provided on an upper side of the wiring plate.

[0015] JPH 11-18331 A describes a stator whose coil ends are connected to axially upstanding contact elements, whereby an annular interconnection element is placed on the front side of the stator, which interconnects the contact elements with the phase connections.

[0016] The invention is based on the object of providing a particularly suitable stator. The invention is further based on the object of providing an electrical machine equipped with such a stator, as well as a laying and contact device therefor.

[0017] The object is achieved according to the invention with regard to the stator by the features of claim 1 and with regard to the electric motor by the features of claim 11, as well as with regard to the laying and contact device by the features of claim 13. Advantageous embodiments and further developments are the subject of the respective subclaims.

[0018] The stator according to the invention is suitable and designed for an electrical machine, in particular for an electric or electromotive power steering system in a motor vehicle. For this purpose, the stator comprises a stator core, in particular a stamped core, which has a number of stator teeth, for example, directed inwards. The stator teeth are provided with a multi-phase rotating field winding, wherein each phase comprises at least one coil or coil winding (phase winding) which has a first and a second coil end. The coils are arranged in particular as individual coils on each stator tooth. Alternatively, double or multiple coils are also conceivable, the coil winding of which is applied to two or more stator teeth.

[0019] A contact device, for example, in the form of a circular ring, is provided for routing, contacting, and connecting the coil ends to the rotating field winding. The contact device has a routing element (router ring) mounted on the front side of the stator core to guide the coil ends. A wiring element (router ring) is mounted on the routing element to connect the coil ends to phase connections on the front side of the stator.

[0020] The laying element has a number of through-openings corresponding to the number of coil ends, each of which opens into a radially and / or tangentially extending guide groove. In other words, the guide grooves can be incorporated into the laying element in a radial or tangential or radially and tangential manner.

[0021] The guide grooves in particular have an approximately V- or U-shaped cross-section and are introduced into the laying element as recesses that are open on the connection element side. The coil ends protrude vertically, i.e. along an axial direction of the stator (stator axis), through the through-openings and are guided in particular at a radial angle along the respective guide groove to a contact point of the guide groove. The coil ends are axially contacted and fixed at the contact points by means of a contact element that is electrically conductively coupled to the connection element. The guide grooves each have a constriction in the axial direction, which secures the coil end guided or seated in the guide groove against axial slipping out.

[0022] This allows for particularly simple assembly of the stator, particularly with regard to connecting the coil ends to the phases or the rotating field winding. Furthermore, the axial contacting using the contact elements automatically enables assembly along the axial direction of the stator, ensuring particularly efficient and simple assembly of the stator.

[0023] When assembling the stator, the coil ends are first guided through the through-holes of the installation element and then bent radially (and / or tangentially) along the guide grooves. The coils are preferably wound from an insulating wire (enamelled wire) as coil wire, so that the coil ends can be easily bent and installed along the guide grooves. However, due to their inherent flexural elasticity, the coil ends have a tendency to spring back into an axially protruding position after being bent along the guide grooves, which would make contact with the interconnection element more difficult. This is advantageously and structurally simply avoided by means of the constrictions integrated into the guide grooves.

[0024] The constrictions thus ensure that the coil ends are held in the plane of the guide grooves for easy contact. In other words, the coil ends are pressed into the guide grooves during the bending process, meaning they are guided through the constriction and thus held in position in the guide grooves, preferably with a positive fit. In other words, the coil end engages in the constriction in such a way that the constriction blocks any movement of the coil end in the axial direction. This reliably and securely holds the coil ends in the guide grooves even during axial contact. This simplifies contact with the interconnection element and thus the assembly of the stator. This subsequently has a beneficial effect on the manufacturing costs of the stator.

[0025] The preferably circular-ring-shaped, preferably one-piece injection-molded element (laying ring) is thus designed as a mechanical support and positioning element for the coil ends. The through-openings are preferably located radially inward in the laying ring, with the guide grooves directed toward the contact points, particularly those located radially outward. This enables particularly effective and simple contacting using the contact elements.

[0026] The guide grooves support and guide the coil wire, which is typically designed as an insulated wire, at the coil ends. Furthermore, the coil ends are insulated from conductive components of the stator and / or electric motor by being guided in the guide grooves. For example, in an electric motor, the coil ends are thus insulated from a motor housing and / or a bearing shield.

[0027] A rotor position sensor for detecting the rotational or angular position of a rotor of the electric motor is preferably arranged in the area of the particularly circular connecting element (connection ring). The axial contact between the connecting ring and the locating ring ensures a defined alignment, which is advantageous with regard to the positioning of a rotor position sensor. This enables a particularly expedient arrangement of the rotor position sensor, which is advantageous for commutation. The rotor position sensor is designed, for example, as a Hall sensor. Furthermore, it is conceivable to arrange further (on-site) sensors and additional functions for determining the condition of the electric machine, such as a temperature sensor for detecting the motor or stator temperature, in the area of the connecting ring.

[0028] In a suitable embodiment, the stator core comprises a stator star and a hollow cylindrical stator yoke pressed onto the stator star, with the stator teeth of the stator star facing (radially) outwards. This results in a simple and cost-effective stator. During assembly, the stator teeth are first wound from the outside with the coil windings and then the stator yoke is pressed onto the stator star. In other words, during a joining process, the stator star equipped with the coils and the stator yoke are joined together during a pressing process, forming the connection points between the tooth tips of the stator teeth and the stator yoke. This allows easier access to the stator teeth during winding, simplifying the assembly with the coil or phase windings.

[0029] In a suitable refinement, the constriction is formed by retaining lugs projecting into the guide groove on both sides. The retaining lugs thus at least partially overlap the opening of the guide groove on the connection ring side, thereby suitably reducing its clear width to a value smaller than the wire diameter of the coil end to be held. This provides a particularly simple and practical, form-fitting holder for the coil ends.

[0030] According to an advantageous embodiment, the coils each have a coil or phase winding, which is applied to a coil carrier (coil body) placed on a stator tooth. In other words, the coil windings forming the coils are each wound around a coil carrier that encompasses the respective stator tooth. The coil carrier, which is preferably made of an insulating material, is, for example, a one-piece or multi-piece, approximately rectangular tube section. The coil carrier preferably has flange collars on the end face, i.e., directed perpendicular to the longitudinal direction of the tooth, between which the available winding space is delimited. The coil carrier thus prevents the rotating field winding from sliding off the teeth of the stator. In this case, it is conceivable, for example, for the coil carriers to be wound first as individual segments and then placed onto the stator teeth.In other words, the coils are preferably designed as individual, separate components.

[0031] In an alternative embodiment, it is also conceivable that one or each stator tooth is directly overmolded with a plastic to form a coil carrier, or that the stator teeth are wound with the rotating field winding without a coil carrier.

[0032] An additional or further aspect of the invention provides that the through-openings of the laying element or laying ring each have a cylindrical opening on the rotating field winding side with an incorporated retaining groove. In the assembled state, a respective coil carrier sits at least partially in the retaining groove, in particular by means of the flange collar. This supports the laying ring on the coil bodies of the stator core. In other words, the coil bodies thus have a supporting function, which improves tolerance compensation and a tight fit of the laying ring or the contact device on the stator star during assembly. This results in a particularly stable stator.

[0033] In a suitable embodiment, the circular ring-shaped locating element has a radially inner inner collar, which, when assembled, at least partially engages a central ring opening of the interconnection element and radially clamps it in place. The locating element or locating ring is thus configured as a centering aid for the interconnection element or interconnection ring. This simplifies the assembly of the stator.

[0034] In an advantageous development, the inner collar of the laying element is segmented with a number of first and second, approximately crenellated collar teeth. The first collar teeth project axially upwards on the laying element in the direction of the interconnection element and clamp it in place when joined. The second collar teeth are formed on the side of the laying element opposite the first collar teeth and thus project upwards in the direction of the rotating field winding or the stator laminated core. When assembled, the second collar teeth engage in a form-fitting manner in a respective, radially inner receptacle or receptacle contour of the coil carriers, in particular their flange collars. This ensures stable and twist-proof assembly of the laying element.

[0035] Alternatively, it is also conceivable for the flange collars of the coil bodies to be provided with upstanding second collar teeth, which, when joined, engage with complementary receiving contours of the laying element. This realizes a (positive) fastening function by means of the collar teeth from the coil carriers towards the laying element.

[0036] In a practical embodiment, the interconnection element or interconnection ring is designed as a preferably multilayer, round or square printed circuit board with a number of conductor tracks. The conductor tracks of the printed circuit board electrically connect the phase connections arranged on an outer side of the interconnection ring facing away from the stator core with the contact elements arranged on the opposite inner side of the interconnection ring. This enables particularly simple and compact routing and connection of the coil ends to the phase connections, which ensures particularly low-effort connection of the phases to the rotating field winding. This creates a particularly advantageous electrical distribution network for the electrical machine in the assembled state.

[0037] In a particularly compact and practical embodiment, the conductor tracks are, for example, axially stacked on top of one another in the circuit board, which is designed, for example, as a circular ring-shaped PCB (printed circuit board). In other words, the conductor tracks are integrated in multiple layers one above the other in the circuit board. The multi-layer and, in particular, one-piece, flat circuit board is thus designed as a particularly space-saving electrical distribution network for the electrical machine or electric motor. This reduces the axial installation space of the stator and thus also of any electrical machine equipped with it. Furthermore, the current-carrying capacity of the circuit board is significantly improved by the use of multi-layer conductor tracks. This enables a greater degree of freedom with regard to the design and architecture of the stator with regard to functional aspects.In particular, an increased fill factor, i.e. an increased number of coil turns, can be achieved with the same axial extension of the stator, which has a beneficial effect on the performance of the electrical machine equipped with it.

[0038] In principle, the number of conductor layers and the technological design of the circuit board can be implemented in different ways. In particular, by selecting the appropriate layout or conductor path, different wiring variants, especially for (multiple) redundant wiring, can be implemented easily and without the need for a geometrically modified component design. This enables a particularly high degree of prefabrication of the stator, since the wiring element is a modular component that can be replaced depending on the application and the desired wiring. This enables a particularly flexible and cost-effective stator.

[0039] In a suitable embodiment, the approximately circular-ring-shaped interconnection element is formed or composed of a number of individual (segmented) circular-ring-sector-shaped partial rings. In other words, the approximately circular-ring-shaped circuit board of the interconnection ring or element is divided into several partial rings or segments. Contact points or connecting elements are suitably provided on the radially directed and mutually facing sector walls of the partial rings, by means of which the partial rings are mechanically and / or electrically conductively coupled to one another in the interconnection assembly of the interconnection element.

[0040] According to a practical development, the contact elements are designed on the laying element side for insulation displacement contact with the coil ends and on the wiring element side for a press-in zone / contact with the wiring element. In other words, the contact element is configured as a multiple contact. This enables a solder-free and tool-free connection and electrical contact between the laying element or the coil ends and the wiring element. This subsequently advantageously translates into a reduction in assembly effort during stator assembly, thereby reducing its manufacturing costs. Furthermore, simple and cost-effective contacting and fixing of the coil ends is achieved. In particular, lower effort with regard to residual dirt requirements is also enabled during stator assembly.

[0041] Suitably, the interconnection element is also mechanically and reliably attached to the installation element by means of insulation displacement and press-in contact.

[0042] The design of the contact elements as insulation displacement contacts significantly simplifies the assembly of the contact device and thus the stator. In particular, the contacting of the coils or coil ends is simplified, as no additional stripping step is required for the insulated coil wire during assembly and wiring.

[0043] In an alternative development, a laser welding process is also possible for contacting and connecting the coil ends to the phase terminals. In particular, the contact elements are arranged in the assembled state in such a way that contacting is possible both by press-fitting and by bonding using soldering or laser welding.

[0044] In a preferred embodiment, the stator according to the invention comprises contact elements that have a terminal connector on the wiring element side with a central contact slot for insulation displacement contact (high-pressure connection). The terminal connector further comprises an axial support surface on which the wiring element is supported in the assembled state. Two extension arms are formed on the terminal connector, which are at least partially bent towards each other to form the contact slot. Depending on the current to be carried, the extension arms each have at least one press-in pin on the wiring element side, with the upper edges of the extension arms being arranged axially offset from the support surface.This results in a particularly advantageous contact element which, on the one hand, enables reliable and secure electrical contact between the coil ends and the interconnection element and, on the other hand, provides a mechanical support function for mounting and holding the interconnection element.

[0045] In a preferred application, the stator is part of an electrical machine, in particular an electric motor, preferably for an electric or electromotive (electromechanical) power steering (EPS) of a motor vehicle. The preferably brushless electric motor comprises a cylindrical motor housing which essentially accommodates the stator in a form-fitting manner. Within the stator, a rotor is preferably arranged so as to be rotatable, together with a rotor-fixed motor shaft. The motor shaft is coupled at the shaft end, for example, to a steering wheel on the one hand and to a steering mechanism of the motor vehicle on the other. The stator according to the invention creates a particularly reliable and effective electrical machine. When used for an electromotive power steering system, the electrical machine is preferably designed with a multiple redundant rotating field winding, so that safe and reliable operation is always guaranteed.

[0046] In a suitable development, the motor housing, in particular a pot-shaped bearing support, is thermally connected to the outside of the interconnection element (connection ring). For this purpose, it is conceivable, for example, for the outside of the interconnection element to be thermally coupled to the motor housing or the bearing support by means of a thermally conductive medium (thermal paste, thermal pad, etc.). This enables simple heat dissipation of the self-heating of the interconnection element that occurs during operation and, in particular, a thermal coupling or connection to the motor housing and / or a motor control system. In other words, the circuit board or the interconnection element can be cooled by means of the bearing support, thereby improving the service life of the electrical machine.The bearing carrier is, for example, a B-side bearing shield of the machine with a bearing seat and a rolling bearing seated therein to support the motor shaft.

[0047] Additionally, it is possible, for example, for the interconnection element and the bearing support to be thermally coupled to the installation element. In particular, the installation element, made of a thermally conductive plastic, for example, suitably has a heat sink function.

[0048] The invention further relates to a routing and contact device for an electrical machine with a rotating field winding having a number of phases. Each phase comprises at least one coil having a first and a second coil end. The routing and contact device is designed with a routing element for guiding and routing the coil ends and with a connection element for connecting the coil ends to phase connections of the electrical machine.

[0049] When assembled, the coil ends protrude vertically through through-holes in the installation element and are guided radially and / or tangentially along a guide groove in the installation element. The guide grooves each open into a contact point, where the coil ends are axially contacted and fixed by means of a contact element electrically coupled to the wiring element. The guide grooves each have a constriction in the axial direction, which secures the coil end, which is guided or inserted in the guide groove in the assembled state, against axial slipping out.

[0050] The routing and contact device according to the invention is not limited to an electrical machine configuration with a stator star and a stator yoke. Rather, the routing and contact device can be used to form an electrical distribution network for a variety of different types or styles of electrical machines and electric motors (segmented electrical machines, solid shaft, hollow shaft, IPM, SPM, reluctance, etc.). The routing and contact device can be used for essentially any electrical machine with toothed motor parts and coils.

[0051] The advantage is that the routing and contact device provides a power contact for the respective electrical machine, which can be mounted in essentially any (rotational) position. Furthermore, the routing and contact device can be easily and cost-effectively implemented with a different number of contact elements. This is particularly advantageous for use in an electric motor with a multiply redundant rotating field winding. This enables particularly flexible and modular adaptation to a specific electric motor or electrical machine.

[0052] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. In simplified and schematic representations, the drawings show: Fig. 1 in perspective a stator star with radial stator teeth, Fig. 2 in perspective a stator with a stator star inserted into a cylindrical stator yoke with wound coil bodies plugged onto the stator teeth, Fig. 3 in perspective the stator with a contact device mounted on it, Fig. 4 partial perspective view of a laying ring of the contact device, Fig. 5 a partial top view of the top side of the laying ring, Fig. 6 partial perspective view of the publisher’s ring with a view of a sub-surface, Fig. 7 in perspective a coil body of the stator, Fig. 8a to 8c, in perspective views a contact element of the contact device, Fig. 9 partial perspective view of a guide groove of the laying ring with an inserted coil end, Fig. 10 a section of the laying ring with a view along a guide groove, Fig. 11 an exploded view of a second embodiment of the stator, Fig. 12 partial perspective view of a contact element of the alternative stator, Fig. 13 a partial sectional view of an electric motor with the alternative stator, Fig. 14 in plan view a connection ring of the contact device of the alternative stator, and Fig. 15. Partial perspective view of an alternative design of the contact device with a phase connection and with a coil end that can be laser welded thereto.

[0053] Corresponding parts and sizes are always marked with the same reference symbols in all figures.

[0054] The Fig. Figure 1 shows a star-shaped stator component, referred to below as stator star 2, which in the exemplary embodiment is manufactured as a laminated core consisting of stator laminations 4 stacked one above the other in layers. The stator laminations 4 are stacked in a stacking direction 8 to form a central, cylindrical opening 6 as a stator bore and are, for example, stamped or punched together. The stator star 2 is part of a Fig. 2 shows a partially wound stator 10 of an electric machine (not shown in detail) of an electric motor-driven power steering system of a motor vehicle. The laminated core of the stator star 2 preferably terminates at its upper side 12 and at its lower side 14 with at least one circumferentially closed stator lamination 4.

[0055] In this exemplary embodiment, the stator star 2 comprises twelve radially outwardly extending stator teeth 16, which form a cylindrical pole piece 18 on the inner side located radially towards the center. The stator teeth 16 are provided with reference numerals in the figures merely as examples. The pole piece 18, which in the assembled state faces a rotor of the electric motor, is only partially closed circumferentially in the stacking direction 8, forming gaps 20 on the pole piece side in order to reduce magnetic short circuits. The stator teeth 16 are provided on the free end with wedge-shaped tooth tips 22, forming contact surfaces 24 located to the left and right of a tooth tip degree.

[0056] The Fig. 2 and Fig. 3 show the stator 10 with a stator core 25, which is joined by a force / friction fit from the stator star 2 and a stator yoke 26 as a result of a pressing process. The stator yoke 26 is made of stacked return ring laminations or stator laminations 28. In the assembled state, the Fig. 2 visible coil windings 30 are placed around the stator teeth 16 of the stator star 2. The coil windings 30, made of insulating wire, are wound as (individual) coils onto coil or winding supports (coil formers) 32 before the stator star 2 and the stator yoke 26 are joined, and are placed with these coil formers onto the stator teeth 16. The coil formers 32 are provided with reference numerals in the figures merely as examples.

[0057] Each of the frame-like coil bodies 32 carries a coil winding or coil 30 as part of at least one stator or rotating field winding 34. The coils 30 can each be contacted via two coil ends 36. The coil ends 36 are provided with reference numerals in the figures merely as examples.

[0058] The total of twenty-four coil ends 36 shown in the Fig. 2 are for further contacting and interconnection by a Fig. The routing and contact device 38 shown in Figure 3 is oriented axially, meaning in the axial direction M (direction of the motor axis). During electromotive operation, the energized windings generate the stator-side magnetic field, which interacts with permanent magnets of the rotor of the brushless electric motor rotating around the central stator or motor axis M. The approximately circular contact device 38 serves to contact and connect the coil ends 36 in a delta or star connection or a combined star-delta connection.

[0059] In the embodiment of the Fig. 3, the twenty-four coil ends 36 are interconnected to form six (motor) phases U, V, W, U', V, and W', each of which is assigned a stator-end phase connection 40 for contacting a motor controller of the electric motor. In this embodiment, the rotating field winding 34 is interconnected, in particular, as two redundant, three-phase rotating field windings with the phases U, V, and W, as well as U', V', and W'. This redundant design is particularly advantageous in terms of safety aspects in an application with an electric motor-driven power steering system.

[0060] The contact device 38 comprises, as basic components, a laying ring 42 placed on the front side of the stator core 25 as a laying element, and a wiring ring 44 placed thereon as a wiring element. The laying ring 42 is designed as a mechanical support and positioning element for the coil ends 36, which are connected by means of contact elements 46 ( Fig. 8a, Fig. 8b, Fig. 8c) are electrically contacted with the interconnection ring 44 for interconnecting the phases U, V, W, U`, V' and W'.

[0061] The following is based on the Fig. 4 to 10 the structure of the laying ring 42 and the contact elements 46 is explained in more detail.

[0062] As particularly in the Fig. 5, the laying ring 42 has, on its radially inner side, a number of round through-openings 48 corresponding to the number of coil ends 36, by means of which the coil ends 36 are guided from a bottom side 50 to a top side 52 of the laying ring 42. The through-openings 48 each open into a guide groove 54 formed in the top side 52 of the laying ring 42, which guide grooves are provided with reference numerals in the figures merely as examples.

[0063] The guide groove 54 ( Fig. 10) extends radially from the respective through-opening 48 to a radially outer contact point 56. Between the through-opening 48 and the contact point 56, a constriction 58 of the guide groove 54 is provided approximately centrally. The constriction 58 is designed as two retaining or clamping lugs 60 projecting into the guide groove 54, which reduce the clear width of the upper slot opening of the guide groove 54. As shown in particular in the Fig. As can be seen in Figure 9, the respective coil end 36 is guided radially angled in the guide groove 54 to the contact point 56 in the assembled state, where it is axially contacted and fixed by means of the contact element 46. The constriction 58 prevents the coil end 36 from axially sliding out of the guide groove 54 during contacting.

[0064] Verlegering 42 has - as particularly in the Fig. 4 and Fig. 6 - has a segmented or toothed inner collar 62 on the radial inside, which circumferentially encloses the central ring opening of the laying ring 42. The inner collar 62 comprises crenellated collar teeth 64 and 66. The collar teeth 64 and 66 are provided with reference numerals in the figures merely as examples.

[0065] The collar teeth 64 are formed on the upper side 52 of the laying ring 42 and protrude upwards along the axial direction M in the direction of the interconnection ring 44. The collar teeth 64 act - as in Fig. 3 - as a centering aid during assembly of the interconnection ring 44. For this purpose, the collar teeth 64 of the inner collar 62 engage at least partially in the central ring opening of the interconnection ring 44. In particular, the interconnection ring 44 is radially clamped during assembly by means of the collar teeth 64 of the laying ring 42.

[0066] The collar teeth 66 are formed on the underside 50 of the laying ring 42 opposite the upper side 52 and project upwards along the axial direction M in the direction of the stator laminated core 25. As can be seen in particular in the Fig. 6, the collar teeth 66 engage circumferentially in corresponding receptacles 68 of the coil carrier 32 in a form-fitting manner in the assembled state. The coil carrier 32 is in the Fig. 7. The receptacles or receptacle contours 68 are in particular incorporated into the radially inner flange collars 70 of the coil carriers 32, which delimit the winding area of the coil carriers 32. The positive retention of the collar teeth 66 in the receptacles 68 of the coil carriers 32 ensures a rotationally secure mounting of the locating ring 42 on the stator laminated core 25.

[0067] As shown by the Fig. 6, the through-openings 48 on the underside 50 of the laying ring 42 each have a cylindrical opening 72, which is provided with a retaining groove 74 in the radially inner region of the laying ring 42. Due to the retaining groove 74, the tubular cylindrical openings 72 have an approximately semicircular cross-sectional shape. The retaining grooves 74 thus create a (joining) area between the collar teeth 66 and the cylindrical openings 72, into which the flange collar 70 of the respective coil carrier 32 can be at least partially inserted. This ensures particularly stable mounting of the laying ring 42 on the coil carriers 32 or on the stator laminated core 25 provided therewith.

[0068] In the area of the contact points 56, the radially guided coil ends 36 are electrically conductively contacted by means of the contact elements 46. The Fig. The contact element 46 shown individually in Figures 8a to 8c is designed for insulation displacement contact with the coil ends 36 on the conductor ring side and for press-fit contact with the conductor ring 44 on the interconnection ring side. The contact element 46 is manufactured, for example, as a metallic stamped and bent part. Fig. 8a shows the contact element 46 in a perspective view. In the Fig. 8b, the contact element 46 is shown with a view of a rear side facing the outer circumference of the laying ring 42 in the assembled state. Fig. 8c shows a front side of the contact element 46 opposite the rear side.

[0069] The electrically conductive contact element 46 comprises a clamping plug 76, which in the clamp-contacted state is oriented tangentially or circumferentially with the respective coil end 36 on the laying ring 42. As can be seen in particular in a summary view of the Fig. 8a with the Fig. 5 and Fig. As can be seen in Figure 9, the approximately rectangular terminal plug 76 has a bend in the areas of the axially directed side edges, which, when assembled, is directed radially inward. A centrally arranged contact slot 78 is formed in the body of the terminal plug 76, which is oriented along the axial direction M.

[0070] As shown by the Fig. As can be clearly seen in Figure 9, the terminal plug 76 is contacted with the coil end 36 by means of the contact slot 78 in the manner of an insulation displacement contact. For this purpose, the contact slot 78 suitably has cutting edges that penetrate the insulating layer of the coil wire of the coil end 36 and thus electrically connect the coil end 36.

[0071] On the curved side edges of the terminal plug 76, a projection arm 82 is formed with a press-in pin 80. Due to the bending of the side edges, the projection arms 82 are oriented towards the contact slot 78. As shown in the top view of the Fig. As can be seen in Figure 5, the contact element 46 has an approximately triangular cross-sectional shape, with the base formed by the terminal plug 76 and the legs formed by the extension arms 82. The extension arms 82 are spaced apart from one another at their free ends so that the respective coil end 36 can be passed between them. The extension arms 82 essentially enclose the opening or mouth of the guide groove 54 in the contact point 56.

[0072] In the contacted state, the contact plug 76 is at least partially seated in a window-like recess 84 of the associated contact point 56, with the extension arms 82 each supported on a support surface 86 of the contact point 56. For this purpose, the upper edges 88 and the lower edges 90 of the extension arms 82 are axially offset relative to those of the clamping plug 76.

[0073] In other words, a first axial, approximately step-like offset is formed between the lower edge 92 of the clamping plug 76 and the lower edge 90 of the extension arm 82, and a second axial, approximately step-like offset is formed between the upper edge 88 of the extension arm 82 and the upper edge 88 of the contact plug 76. The upper edge 94 of the contact plug 76, also referred to below as the support surface, is designed in particular to support the interconnection ring 44 placed on the laying ring 42. In other words, in the assembled state, the interconnection ring 44 does not sit on the laying ring 42 but merely on the support surfaces 94 of the contact elements 46, wherein the contact elements 46 are supported on the support surface 86 by means of the respective extension arms 82.

[0074] During assembly, the press-in pins 80 of the extension arms 82 are each pressed into a corresponding contact opening 96 of the interconnection ring 46 in the manner of a press-fit contact. The support of the extension arms 82 on the support surfaces 86, on the one hand, and the support of the interconnection ring 44 on the support surfaces 94, on the other, ensure simple, reliable, and uniform contact between the press-in pins 80 and the contact openings 96. For example, it is conceivable that the coil ends 36 are first cut-contacted using the terminal plugs 72, and then the interconnection ring 44 is electrically conductively coupled to the coil ends 36 via the press-fit contact with the press-in pins 80.Alternatively, it is also conceivable, for example, that the interconnection ring 44 is first connected to the press-in pins 80 of the extension arms 82, and then the interconnection ring 44 is placed with the contact elements 46 onto the laying ring 42. Advantageously, the contact elements 46 create both an electrical coupling between the coil ends 36 and the interconnection ring 44 and a mechanical coupling between the laying ring 42 and the interconnection ring 44.

[0075] Based on the Fig. 11 to 14, a second embodiment of the stator 10 is explained below.

[0076] The embodiment of the Fig. 11 to 14 differs from the above-described embodiment essentially in the structure of the contact device 38'. Fig. 11 shows the stator 10 in a disassembled state. As in the Fig. As can be seen in Figure 11, the connecting ring 42 of the contact device 38' in this embodiment has only the collar teeth 66 as the inner collar 62. The connecting ring 44 connects the coil ends 36 to three phases U, V, and W.

[0077] In the Fig. 12 shows the contact element 46 of the contact device 38'. In this embodiment, the contact element 46 has an unbent terminal plug 76 for insulation displacement contact with the phase end 36. The extension arms 82 extend in the same plane as the terminal plug 76. The contact element 46 can thus be manufactured with little effort and at reduced cost, for example, as a stamped part.

[0078] The Fig. 13 shows a section of an electric motor 98 as an electrical machine with the stator 10. The electric motor 98 comprises a motor housing 100 into which the stator 10 is inserted. The motor housing 100 has a cover-like bearing support 102, which covers the housing opening of the motor housing 100 at the front. The bearing support 102, in particular on the B-side, has a cover edge 104, which rests circumferentially against the motor housing 100.

[0079] Radially offset inwardly to the cover edge 104, the bearing carrier 102 has, in the sectional view of the Fig. 13 a first step-like shoulder 106. Between the cover edge 104 and the shoulder 106, an annular installation space is thus provided for the areas of the press-in pins 80 and the phase connections 40 projecting upwards from the interconnection ring 44. A second step-like shoulder 108 is provided radially inside the shoulder 106, through which a central bearing seat 110 of the bearing support 102 is formed. Between the shoulders 106 and 108, the bearing support 102 has a material thickening 112 oriented towards the interconnection ring 44, which surrounds the bearing seat 110. The material thickening 112 forms a shoulder on the underside, i.e. the side facing the interconnection ring 44, by means of which the bearing support 102 - as in Fig. 13 - at least partially engages in the ring opening of the interconnection ring 44 or the contacting device 38'. In other words, the bearing seat 110 engages at least partially in the contacting device 38' and the opening 6 of the stator core 25, thereby forming a particularly compact and space-saving electric motor 98.

[0080] In the assembled state of the electric motor 98, an electronics housing 114 with a motor control unit 116 (ECU: electronic control unit) accommodated therein is mounted on the bearing support 102. The motor control unit 116 comprises an electrical intermediate circuit 118, which is connected to a power circuit 120 with a number of semiconductor switches 122. The motor control unit 116 further comprises an interference suppression module 124 and a controller 126, which is signal-coupled to a rotor position sensor (not shown in detail) for detecting and monitoring the rotor position during operation of the electric motor. The rotor position sensor is preferably arranged in the region of the contact device 38', for example, on the interconnection ring 44.

[0081] As shown in the sectional view of the Fig. 13 clearly shows that the Fig. 14, the interconnection ring 44, shown in a highly simplified manner, has three conductor tracks 128 arranged axially stacked one above the other, wherein the conductor tracks 128 are provided with reference numerals in the figures merely as examples. The interconnection ring 44 is designed in particular as a printed circuit board, for example as a PCB (printed circuit board), in which the approximately circular conductor tracks 128 are integrated. For the purpose of interconnection to the rotating field winding 38, the conductor tracks 128 are each contacted, on the one hand, with the corresponding phase connections 40 of phases U, V, and W and, on the other hand, with the corresponding contact openings 96 of the associated coil ends 36.

[0082] As in the Fig. 14, the interconnection ring 44 of the contact device 38' in this exemplary embodiment is segmented as composable partial rings 130a, 130b, and 130c. The partial rings 130a, 130b, and 130c are each configured as a 120° circular ring sector segment, which are electrically and mechanically connected to one another at the corresponding contact points.

[0083] The outer or upper side 132 of the interconnection ring 44, on the one hand, and the semiconductor switches 122 of the power circuit 120, on the other hand, are thermally connected to the bearing support 102 by means of a thermally conductive layer 134. This enables heat dissipation of the motor electronics 116 and the contact device 38' via the bearing support 102 to the motor housing 100. The thermal coupling or connection to the motor housing 100 enables heat dissipation of the self-heating of the contact device 38' and the motor electronics 116. As a result, the electric motor 98 has improved thermal stress resistance. The thermal coupling or heat dissipation is Fig. 13 shown schematically with arrows.

[0084] In the Fig.15 shows a simplified representation of an alternative embodiment of the contact device 38". In this embodiment, the coil end 36 is guided approximately vertically through the interconnection ring 44. The coil end 36 is guided in particular directly to a phase connection 40, so that a simple soldering or laser welding connection of the coil end 36 to the phase connection 40 is possible.

[0085] The invention is not limited to the exemplary embodiments described above. Rather, other variants of the invention can also be derived therefrom by those skilled in the art without departing from the subject matter of the invention. In particular, all individual features described in connection with the exemplary embodiments can also be combined with one another in other ways without departing from the subject matter of the invention.

[0086] For example, it is conceivable to equip the stator core 25 with double coils, with one coil winding 30 being wound on two coil carriers 32. The connecting ring 42 and the interconnection ring 44 of the contact device 38, 38' have a correspondingly reduced number of elements involved in the interconnection to the rotating field winding 34.

Claims

[1] Stator (10) of an electrical machine (98), in particular for a motor vehicle, with a stator laminated core (25) which has a number of stator teeth (16) and is provided with a rotating field winding (34) arranged on the stator teeth (16) and comprising a plurality of phases (U, V, W, U', V', W'), wherein each phase (U, V, W, U', V', W') comprises at least one coil (30) which has a first and a second coil end (36), and with a contact device (38, 38', 38") comprising a laying element (42) placed on the end face of the stator laminated core (25) and a wiring element (44) placed thereon for wiring the coil ends (36) to phase connections (40) on a stator end face, - wherein the coil ends (36) protrude vertically through through-openings (48) of the laying element (42) and are each guided radially and / or tangentially angled along a guide groove (54) of the laying element (42) and are axially contacted and fixed at a contact point (56) of the guide groove (54) by means of a contact element (46) electrically conductively coupled to the interconnection element (44), and - wherein the guide grooves (54) each have a constriction (58) in the axial direction (M), which secures the coil end (36) guided in the guide groove (54) against axial sliding out. [2] Stator (10) according to claim 1, characterized by that the constriction (58) is formed by retaining lugs (60) projecting into the guide groove (54) on both sides thereof. [3] Stator (10) according to claim 1 or 2, characterized bythat the coils (30) each have a coil winding which is applied to a coil carrier (32) which is placed on a stator tooth (16). [4] Stator (10) according to one of claims 3, characterized by that the through-openings (48) of the laying element (42) each have a cylindrical opening (72) on the rotating field winding side with an introduced holding groove (74) in which a coil carrier (32) is at least partially seated. [5] Stator (10) according to one of claims 1 to 4, characterized by that the laying element (42) has a radially inner inner collar (62) which, in the assembled state, engages at least partially in a central ring opening of the interconnection element (44) and radially clamps it. [6] Stator (10) according to claim 5, characterized bythat the inner collar (62) of the laying element (42) is designed in segments with a number of first and second collar teeth (64, 66), wherein the first collar teeth (64) project axially upwards in the direction of the interconnection element (44) and clamp the interconnection element (44), and wherein the second collar teeth (66) project axially upwards in the direction of the rotating field winding (34) and engage positively in a respective, radially inner, receptacle (68) of the coil carriers (32). [7] Stator (10) according to one of claims 1 to 6, characterized by , wherein the interconnection element (44) is designed as a, preferably multi-layer, printed circuit board with a number of conductor tracks (128) which electrically connect the phase connections (40) arranged on an outer side (132) of the interconnection element (44) facing away from the stator laminated core (25) to the contact elements (46) arranged on the opposite inner side of the interconnection element (44). [8] Stator (10) according to claim 7, characterized by that the interconnection element (44) is formed from a number of individual circular sector-shaped partial rings (130a, 130b, 130c). [9] Stator (10) according to one of claims 1 to 8, characterized by that the contact elements (46) are designed on the laying ring side for insulation displacement contact with the coil ends (36) and on the wiring ring side for press-in contact with the wiring element (44). [10] Stator (10) according to claim 9, characterized by , - that the contact element (46) comprises a clamping plug (76) on the laying element side with a central contact slot (78) and an axial bearing surface (94) for the interconnection element (44), and - that two extension arms (82) are formed on the terminal plug (76) and are at least partially bent towards one another to form the contact slot (78), each having a press-in pin (80) on the circuit element side, the upper edge (88) of which is offset axially inwardly relative to the support surface (94). [11] Electric machine (98), in particular electric motor, preferably for a power steering system, with a stator (10) according to one of claims 1 to 10. [12] Electric machine (98) according to claim 11, characterized by that a motor housing (100), in particular a pot-shaped bearing support (102), is connected to the outer side (132) of the interconnection element (44) by means of thermal conduction. [13] Laying and contact device (38, 38', 38'') for an electrical machine (98) with a rotating field winding (34) with a number of phases (U, V, W, U', V', W'), each phase (U, V, W, U', V', W') comprising at least one coil (30) having a first and a second coil end (36), with a laying element (42) for guiding and laying the coil ends (36) and with a wiring element (44) for wiring the coil ends (36) to phase connections (40) of the electrical machine (98), - wherein, in the assembled state, the coil ends (36) protrude vertically through through-openings (48) of the laying element (42) and are each guided radially and / or tangentially along a guide groove (54) of the laying element (42) and are axially contacted and fixed at a contact point (56) of the guide groove (54) by means of a contact element (46) electrically conductively coupled to the interconnection element (44), and - wherein the guide grooves (54) each have a constriction (58) in the axial direction (M), which secures the coil end (36) guided in the guide groove (54) in the assembled state against axial sliding out.

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