Electric motor, in particular of a vehicle component

An electric motor of a vehicle component, in particular a window opener drive or seat adjuster drive, includes a rotor, a stator with a three-phase stator winding having at least one coil per phase with first and second coil ends, and a connection element having a number of vias corresponding to the number of coil ends, the vias forming first and second contacting groups. The vias of the first contacting group are paired with a contact ring with contact points for electrically conductively connecting the first coil ends, in particular while forming a neutral point. The second coil ends are guided through the vias of the second contacting group, and a coil end portion or additional conductor element of the coil ends is azimuthally guided along the connection element and guided, preferably axially, out of the connection element while providing a three-phase winding connection at exposed positions.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention relates to an electric motor, in particular of a vehicle component, for example of a window opener or a seat adjuster drive, comprising a rotor and comprising a stator with a three-phase stator winding with at least one coil (coil winding) for each phase, and also comprising a connection element.

An electric motor comprising a stator having twelve stator windings is known from DE 10 2009 036 128 A1, said stator windings being connected partially in series and ultimately forming a star connection. A supporting element and a conductive track structure formed from four wires are provided for the connection, said wires being received by the supporting element in that the wires are clipped into said supporting element. The wires form a complete ring or partial ring portions, wherein such a wire forms the star connection as a complete ring in conjunction with the coil ends of the stator windings. The supporting element has axial guides for an axial guidance of the coil ends. An ultimate electrical connection between the coil ends and the respective wires is produced by soldering, welding or staking.

US 2011/0057524 A1 discloses an electric plug connector arrangement for a brushless electromagnetic motor. This comprises a three-phase stator winding having a number of windings per phase, which are connected either in parallel or in series. The plug connector arrangement comprises an annular wire guide element for receiving the ends of the windings and also a connecting receptacle in the form of three annular connecting rails, which each have a cable shoe as an end. In addition, the connecting rails have axially widened wire clamps for securing the electrical contact for the three phases through the slots in the wire guide element.

A stator for an electric motor with annular stator stack having a plurality of stator teeth is known from US 2005/0088049 A1. An annular connecting unit is mounted on an end side or end face of the stator. The annular connecting unit comprises deflection elements and also a supporting element, which is equipped with a receptacle and slots. A series of connecting rings insulated from one another are located in the receptacle and each comprise contact elements guided outwardly through the slots.

DE 10 2007 040 809 A1 discloses a three-phase motor comprising a plurality of phases of a stator having coils connected in parallel. The stator has annular contact rails for contacting the coils, which are in turn formed with groove-shaped contact holders as a structural unit. The contact holders are manufactured from plastic and are injection molded onto the coils.

BRIEF SUMMARY OF THE INVENTION

The object of the invention is to provide the simplest possible connection of the stator or phase windings of an electric motor, which connection can be produced with minimal outlay, i.e. with a minimized number of rails or contact rings or of additional process steps, such as soldering, welding or staking of wires and coil ends of the phase windings.

This object is achieved in accordance with the invention by an electric motor, comprising a rotor, a stator with a three-phase stator winding having at least one coil with first and second coil ends per phase, a connection element having a number of contact vias corresponding to the number of coil ends, the vias forming a first and a second contacting group, the contact vias of the first contacting group being assigned a contact ring with contact points for the electrically conductive connection of the first coil ends, in particular while forming a neutral point, and the second coil ends being guided through the contact vias of the second contacting group and azimuthally guided via a coil end portion along the connection element and guided, preferably axially, out from the connection element while providing a three-phase winding connection at exposed positions. Advantageous embodiments are specified in the dependent claims.

In accordance with the invention the electric motor of the type mentioned in the introduction has a connection element having a number of contact vias corresponding to the number of coil ends. The connection element is expediently ring-shaped or annular and is adapted suitably here to the diameter of the stator in such a way that it can be arranged on an end face of the stator and can be fixed there.

Each coil end is connected to the corresponding coil ends of the two other phases, preferably while forming a neutral point, by means of a contact ring, which is assigned to the connection element and expediently is laid therein.

For this purpose a first contacting group forms a first number of contact vias, each of which is assigned to a contact point of the contact ring, in particular while forming a neutral point for the electrically conductive connection of the first coil ends.

The respective other (second) coil end is wired so as to be guided out from the connection element in order to electrically contact a control electronics unit at an exposed point. For this purpose a second contacting group forms a second number of contact vias, via which the second coil ends are guided through. The second coil ends for this purpose form coil end portions that are azimuthally guided along the connection element, i.e. preferably extend over or in said connection element on the outer circumferential side. The coil end portions are guided, preferably axially, out from the connection element, while providing a three-phase winding connection at exposed positions. The connection element is preferably annular.

Alternatively, the contact vias of the second contacting group may be assigned separate conductor elements for the electrically conductive connection to the second coil ends. In this second variant the conductor elements each form a conductor portion between a connection end and a contact end, said conductor portion being azimuthally guided along the connection element. In order to provide the three-phase winding connection, the connection ends of the conductor elements are then guided out from the connection element at the exposed positions, in particular again axially. The preferably annular connection element in this second variant forms an adapter so to speak.

In both variants the connection element serves for the connection-secure contacting of the usually comparatively large number of coil ends of the stator winding with a three-phase connection of a control circuit or control electronics unit, wherein the connection element already contains the in-phase connection of the coils of the stator winding, preferably in a star connection.

The connection element can thus be manufactured as a separate component and, for particularly easily handled assembly, can be provided with the stator of the electric motor supporting the stator winding with additionally reliable and fail-safe contacting and connection of the coils of the stator winding. Contact that can be assembled or produced in a simple and reliable manner with an electronics unit supplied in particular by a vehicle on-board network and/or with a current or voltage source is thus given, wherein the three-phase connection ends already can be positioned optimally.

In an advantageous embodiment the winding connections are held at exposed points—in relation to the motor axis—in the axial direction of the connection element. For this purpose the connection element has a corresponding number of retaining elements, which hold or at least support the winding connections or the connection ends of the conductor or coil end portions at the exposed points, preferably axially oriented. The retaining elements, which are preferably formed integrally on the connection element, form the transition point so to speak between the conductor or coil end portion and the winding connections. A stable arrangement is thus created for the further assembly of the electric motor.

In accordance with an expedient development the connection element comprises an annular frame part, in which the contact ring is laid. The frame part suitably has a circumferential wall and a radial inner collar formed integrally thereon. The contact vias are preferably formed in a manner running axially in the frame collar, whereas the azimuthal grooves for the coil ends or conductor portions of the connection element are provided in the circumferential wall, preferably on the outer circumferential side. These portions are thus guided circumferentially in the connection element (guide ring) and can be held there in an electrically insulated manner.

The contact ring is preferably formed with contact points bent out in a loop-like manner, which are aligned with the contact vias of the first contacting group in order to receive and contact the first coil ends.

In accordance with a suitable embodiment of the connection element, radially arranged detent elements for securing the connection element to the stator are provided. For this purpose the detent elements are distributed over the circumference of the frame part and are suitably formed integrally on the inner circumference of the inner collar. In order to produce the latched connection to the connection element, stator-side winding frames having corresponding detent elements are assigned to the coils.

In accordance with an expedient development a cover element is provided, which can be fixed to the connection element, in particular can be latched thereto. In this way the azimuthally guided portions (wire portions) can be protected, for example against soiling, and instances of faulty contact in the motor housing can be avoided.

The cover element suitably has a number of guide elements, which preferably are raised in a dome-like manner or are hood-like, corresponding to the number of phases. The winding connections are guided axially out from the connection element, via these guide elements of the cover element, for contact with a control electronics unit, wherein the direction reference is again based on the motor axis. This provides the wiring portions (coil end portions or conductor portions), which serve as winding connections or are effective as such, with a high stability for contact with a control unit (electronics unit) or with a current or voltage source (vehicle battery or vehicle on-board network).

In accordance with a suitable embodiment the cover element has at least one detent element for latching with the connection element. The cover element may therefore be fixed to the connection element easily and securely.

Both the connection element and the cover element are advantageously annular, and are produced expediently from an insulating material. A reliable, simple and space-saving assembly is thus enabled on the one hand, and on the other hand the coil ends or conductor elements can be guided without further insulation in the connection element at the exposed points.

Parts corresponding to one another are provided in all figures with the same reference signs.

DESCRIPTION OF THE INVENTION

FIG. 1shows an electric motor1with a stator2and with a rotor3in a perspective illustration, whereasFIG. 2shows part of the stator2of the electric motor1without yoke. The stator2cooperates in the usual manner with a rotor3. The stator2is assigned a yoke4as laminated core, which is shown inFIG. 1and is removed inFIG. 2, such that the star-shaped laminated core of the stator2can be seen there. The stator laminations stacked to form this core usually consist of soft-magnetic iron.

The stator2, while forming stator grooves not designated in greater detail, has radially outwardly directed stator teeth5, onto which frame-like winding carriers6are fitted. Each of the frame-like winding carriers6carries a coil or coil winding7as part of the stator winding. Each two successive coils7are continuously connected and form a coil pair with the coils7in series connection. The coil pairs can each be contacted via two coil ends8,9. The total of twelve illustrated coil ends8,9, specifically six first coil ends8and six second coil ends9, are oriented or organized in the direction of the motor axis A (i.e. axially) for further contact by a connection element10described in greater detail hereinafter.

FIG. 3shows the preferred embodiment of the connection element10, which serves to contact and connect the coil ends8,9and is ring-shaped for this purpose. The connection element10comprises an annular frame part11with a radial inner collar11aand with a circumferential wall11b.

An annularly bent contact ring12lies in the frame part11and here expediently bears against the inner circumference thereof. The contact ring12is locally bent out specially at exposed positions so as to form there U-shaped or semi-circular contact points or loops13, which extend radially within the connection element10. Axially oriented detent elements14distributed over the inner circumference of the annular connection element10are formed integrally on the frame part11.

Furthermore, groove-like or notch-like recesses15are formed in the circumferential wall11bof the frame part11and are open suitably on the outer circumferential side for simple handling during assembly. Pawl-, pin-, or hook aperture-like retaining elements16are formed integrally on the circumferential wall11bof the frame part11on each side of the respective recess15. The recesses15form exposed points, as will be described in greater detail hereinafter.

As can be clearly seen by way of comparison fromFIG. 6, base-side contact vias17for passing through and/or contacting the coil ends8and9sticking up axially in accordance withFIG. 2are formed in the frame collar11aof the frame part11and thus in the connection element10. The contact vias or openings17are distributed over the circumference, wherein the distribution pattern thereof is adapted to the respective circumferential positions of the coil ends8and9according toFIG. 2. The stator-side circumferential positions of the coil ends8and9may also be adapted to the corresponding feedthrough positions of the contact vias17of the connection element10.

In addition, grooves18open in the circumferential wall11bof the frame part11on the outer circumferential side are provided along the outer circumference of said frame part11and may also be produced by the forming of accordingly extending wall webs in the circumferential wall11b. These azimuthally extending grooves18(azimuthal grooves) of the connection element10lead into the recesses15from each side thereof and therefore lead into the exposed points.

The connection element10receives the coil ends8,9shown inFIG. 2in order to contact and to connect these. As can be seen fromFIGS. 2 and 6in conjunction by way of example withFIGS. 1, 4 and 7, the coil ends8and9penetrate into the contact openings17when the connection ring10shown from beneath inFIG. 6is joined to the wound stator2shown inFIG. 2.

In accordance with the preferred exemplary embodiment the first coil ends8penetrate here into each second contact opening17, whereas the second coil ends8penetrate into the contact openings17arranged therebetween. The contact openings17assigned to the first coil ends8here form a first contacting group, whereas the contact openings17associated with the second coil ends9form a second contacting group, of which the contact openings17are aligned with the specially shaped or bent-out contact points13of the contact ring12. There, the first coil ends8are contacted by clamping in the joining position at the contact points13, in particular on account of the loop-shaped embodiment thereof, and are connected by means of the contact ring12, preferably to form a neutral point of the stator winding.

The second coil ends9are guided within the connection element10through the corresponding contact openings17and then azimuthally along the outer circumference of the frame part11. Alternatively, the second coil ends9in the corresponding contact openings17can be contacted with separate conductor elements in the form of wire pieces or the like.

These contact openings17of the connection element10form a second contacting group. An improved guidance and/or holding of the second coil ends9is advantageously achieved in that the contact openings17of the second contacting group have a comparatively long guide channel, which is produced by dome-like contact attachments20raised in the axial direction. These contact attachments20are provided on the side of the frame part11opposite the stator2, on the inner collar11aof said frame part in the region of the contact openings17of the second contacting group, and are advantageously formed integrally thereon. In the variant with separate conductor elements the second coil ends9are contacted with the conductor elements within these contact attachments or channels20.

Whereas for the first coil ends8clamping contacts so to speak are thus provided via the contact openings17of the first contacting group in conjunction with the contact ring12and in particular contact points13thereof by means of the connection element10, the connection element10for the second coil ends9forms plug contacts so to speak via the contact openings17of the second contacting group and in particular by means of the contact attachments20, when separate conductor elements are provided.

As can be clearly seen by way of comparison fromFIGS. 3 and 4, the second coil ends9each have a coil end portion19, in which azimuthal grooves18are guided and laid therein. In the embodiment with separate conductor elements, these are corresponding conductor portions. Connection ends19aof the coil ends9or of the conductor elements adjoining these portions19are bent in the recesses15of the connection element10at the aperture-like retaining elements16, such that these connection ends19aextend in the axial direction A at the exposed points formed by the recesses15and form three-phase winding connections.

The coil ends9, i.e. the winding connections19aat the coil end portions19thereof or at the conductor portions of the additional conductor elements, are oriented in pairs in the three recesses or exposed points15provided in the present case. On the whole, a three-phase connection configuration is thus formed, consisting of connections19acontacted and connected with in each case two second coil ends9, said connections being intended to provide three-phase power to the stator winding.

In the exemplary embodiment twelve stator teeth5are provided, each having a winding carrier6and at least one coil7thereon, with a total of twelve coil ends8,9. The connection element10makes it possible to provide a three-phase connection wiring of the electric motor1with simple assembly and in particular simple wiring.

The connection element10additionally provides a particularly suitable, easily handled and in particular space-saving guidance of the second coil ends9in the azimuthal grooves18along the outer circumference of the frame part11. The retaining elements16on the outer circumference of the enclosing wall11bof the frame part11here allow a sufficiently secure fixing and positioning of the connections19of the second coil ends9.

The detent elements14preferably formed integrally on the connection element10enable simple and reliable latching between the connection element10and the stator2as these two joining parts2,10are joined during the course of assembly. The detent elements14of the connection element10here engage with corresponding detent elements21in the form of detent loops, which are formed integrally on the winding carriers6of the coils7and extend in the axial direction A. Since on the one hand the stator teeth5extend in the radial direction R (FIG. 1) and the winding carriers6are fitted hereon, and since on the other hand the winding carrier-side detent elements21extend in the axial direction A, it is ensured that the connection element10is held reliably on the stator2.

As can be seen in particular fromFIGS. 5 and 6, the connection element10has a cover element22. This is preferably likewise ring-shaped and is adapted to the contour of the frame element11and in particular to the circumferential wall11bthereof in order to cover this and in particular to cover or to close the azimuthal grooves18in a manner protected to the greatest possible extent against dust and soiling. The cover element22is preferably latched to the frame part11in order to reliably join these two parts10,22to one another. For this purpose, a number of detent elements23are formed integrally on the hood-like cover element22on the outer circumferential side and cooperate with corresponding detent contours of the frame part11to produce the latched connection.

Dome-like guide sleeves raised in the axial direction A are formed integrally on the cover element22as guide elements24for the connections19aof the second coil ends9. The guide sleeves24are aligned with the recesses15in the frame part11of the connection element10, said recesses forming the exposed points. On the head side, opening pairs25are formed in the guide sleeves24, via which the connections19aof the coil ends9serving as three-phase winding connections are guided out and are thus stabilized in an accurately positioned manner.

FIG. 7shows the stator2with assembled connection element10inclusive of the cover element22thereof. As can be seen, the connections19acontacted with the second coil ends9by means of the connection element10protrude out from the connection element10in the axial direction A via the corresponding end face of the stator2in an exactly positioned and securely held manner and form the winding connections of the stator winding for connection to a control electronics unit for supplying three-phase power to the electric motor1. As can be seen, the stator2is surrounded by the stator yoke4, which is reliably contacted with the free ends of the stator teeth5, for example by staking.

The invention is not limited to the above-described exemplary embodiments. Rather, other variants of the invention can also be derived herefrom by a person skilled in the art without departing from the subject matter of the invention. In particular, all individual features described in conjunction with the exemplary embodiments can also be combined differently with one another without departing from the subject matter of the invention.

LIST OF REFERENCE SIGNS