ELECTRIC MACHINE

An electric machine, e.g., an electric motor for a fan, and a method of manufacturing are disclosed. The electric machine includes a rotor that rotates in operation about an axis of rotation that is parallel to a motor axial direction, a stator extending in a motor circumferential direction, and a carrier extending radially with respect to the motor axial direction. The stator is attached to the carrier. At least one pin is arranged radially offset to the axis of rotation is fixed to the carrier and projects axially from the carrier. The stator is axially pressed onto the at least one pin so that the stator is attached to the at least one pin via a press fit and so that the press fit positions the stator relative to the carrier and fixes the stator to the carrier.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to European Application No. EP 23186698.9 filed on Jul. 20, 2023, the contents of which are hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to an electric machine, in particular an electric motor for a fan, having a stator and a carrier to which the stator is fixed. The invention further relates to a method for manufacturing such an electric machine.

BACKGROUND

An electric machine has a stator and a rotor which interact electromagnetically during operation, so that the rotor rotates relative to the stator about an axis of rotation. For reliable operation, the rotor and stator have to be positioned relative to one another, in particular coaxially. Positioning is usually achieved by fixing the stator to a carrier. For this purpose, the stator is usually positioned accordingly relative to the carrier, attached to the carrier and then fixed to the carrier by means of screw connections.

Such an electric machine is known from WO 2019/002266 A1. The stator of the electric machine extends in a circumferential direction in a closed hollow-cylindrical manner. The carrier has a carrier plate, wherein the stator is attached to the carrier plate of the carrier using screw connections.

The present invention is concerned with the problem of providing an improved or at least alternative embodiments for an electric machine of the type mentioned above and for a method for manufacturing such an electric machine.

This problem is solved according to the invention by the object of the independent claim(s). Advantageous embodiments are the subject of the dependent claims.

SUMMARY

Accordingly, the present invention is based on the basic idea of positioning and fixing a stator of an electric machine to a carrier of the electric machine by means of press fit between stator pins fixed to the carrier and projecting the carrier. Thus, a reliable and stable as well as defined positioning and fixing of the stator within the electric machine is achieved. Moreover, in this way, no other separate connecting means, such as screws and the like, are necessary for fixing and positioning the stator to the carrier. Thus, the fixing and positioning of the stator to the carrier are preferably free of screw connections. The thus achieved simplified manufacture of the electric machine leads to a cost-effective as well as to a decrease in the cycle time in manufacturing the electric machine. The press fit between the respective pin and the stator further leads to a direct contact between the stator and the respective pin. This leads to a heat transfer from the stator to the respective pin and thereby to the carrier. Thus, a simplified and improved cooling of the stator is achieved.

According to the idea of the invention, the electric machine has a rotor and the stator. The rotor rotates in operation about an axis of rotation of the electric machine. The axis of rotation runs parallel, particularly coaxial with an axial direction of the electric machine. The axial direction of the electric machine is also referred to as motor axial direction in the following. The stator extends in a circumferential direction of the electric machine. The circumferential direction of the electric machine is also referred to as motor circumferential direction in the following. The carrier extends radially with respect to the motor axial direction. At least one pin is fixed to the carrier and projects axially from the carrier plate.

The at least one pin is radially offset to the axis of rotation. The stator is axially pressed onto the at least one pin so that the stator is attached to the respective pin by means of a press fit, wherein the at least one press fit positions the stator relative to the carrier and fixes the stator to the carrier. The press fit to the axial pins further enable centering of stator to the carrier. This eliminates the requirement for additional tooling, devices or dedicated positioning features and the like for centring purposes.

Preferably the direct contact between the respective pin and the stator is thermally and electrically conductive. This leads to an improved heat transfer as well as said parts of the stator and the corresponding pin being electrically equipotential. Thus improved cooling as well as improved compensation of unwanted electromagnetic interference are achieved.

Particularly preferred are embodiments in which the stator as a whole is positioned and fixed to the carrier by means of the at least one press fit. Preferably, positioning and fixing are achieved exclusively by means of the press fit. Thus, the positioning and fixing of the stator in the electric machine is free of screw connections. This leads to a considerable simplification of the manufacture of the electric machine with a significant decrease in the cycle time in production.

The respective pin is conveniently electrically conductive, for example made of a metal or metallic alloy.

Cooling and electromagnetic compensation are more distinct and improved if the pins are each thermally and electrically connected to the carrier. Conveniently, the carrier is electrically conductive and electrically grounded.

The carrier can have ribs which project axially, for example. This improves thermal dissipation of the electric machine and in particular of the stator and thus leads to better cooling.

The stator conveniently has a laminated stack, also referred to as laminated core in the following. The laminated core has successive laminations along the axis of rotation and thus axially successive lamination. In particular, the laminated core consists of the axially successive lamination. The laminated core serves in particular to guide fields generated during operation of the electric machine for electromagnetic interaction. For this purpose, at least one winding/coil of the stator can be wound around the laminated core.

The stator extends in the motor circumferential direction, preferably closed, and further in the axial direction. The stator is thus shaped in the manner of a hollow cylinder.

The electric machine is advantageously designed as an electric motor.

The electric machine, in particular the electric motor, can be used in any application.

In particular, the electric machine may be part of a fan, with the rotor being connected to fan blades of the fan.

The electric machine may have one single pin.

Preferably the electric machine comprises at least two such pins wherein the pins are distanced to one other in the motor circumferential direction. For instance, the electric machine can have three pins. The pins preferably have the same radial distance to the axis of rotation. The pins preferably have the same circumferential distance to one other, that is distributed equally along the motor circumferential direction.

The rotor is beared so that it can rotate about the axis of rotation. The bearing can be mounted on the carrier, that is the rotor can be rotatably mounted on the carrier. For this purpose, an axially extending bolt can be fixed to the carrier and the rotor can be rotatably mounted on the bolt. The at least one pin is thus radially distanced to the bolt.

A method for manufacturing of the electric machine preferably includes providing a carrier assembly, a stator assembly and a rotor assembly. The carrier assembly comprises the carrier and the at least one pin fixed to the carrier. The stator assembly comprises the stator at least partially. The rotor assembly comprises the rotor at least partially. For manufacturing, the stator assembly is axially press fitted onto the at least one pin, such that the stator assembly is positioned and fixed to the carrier. In addition, the rotor assembly is ratably fixed to the carrier, in particular by using said bolt.

The respective pin can be fixed to the carrier in any way.

Preferably, the respective pin is overmolded with the carrier. The respective pin can be inserted as an insert in an injection mold and then the carrier can be produced by injection molding in such a way that the pins are fixed to the carrier and project axially from the carrier. That is, the carrier is manufactured by injection molding. Here, the at least one pin is inserted as an insert in an injection mold and then the carrier is manufactured by injection molding such that the at least one pin is fixed to the carrier and projects axially from the carrier.

The bolt may be fixed to the carrier like the at least one pin. That is, the bolt may be used as an insert in the injection mold and then the carrier manufactured by injection molding such that the bolt is fixed to the carrier and projects axially from the carrier.

The carrier is preferably electrically conductive. For example, the carrier may be made of a metal or metallic alloy, such as aluminium, in particular by injection molding.

In preferred embodiments, at least one of the at least one pins axially exceeds the stator on the side averted from the carrier with section of the pin. The section is also referred to below as extension section in the following. That is, at least one of the at least one pins has an extension section which axially extends the stator on the side averted from the carrier. At least one of the at least one extension sections is deformed after the stator has been pressed onto the at least one pin, so that the extension section axially presses the stator against the carrier. Preferably each of the pins comprises such an extension section and each extension section is deformed after the stator has been pressed onto the respective pin to axially press the stator against the carrier. This leads to a prevention or at least reduction of axial clearance between the stator and the respective pin. Hence, an additional fixing and thus fastening of the stator to the carrier is achieved by still using the at least one pin.

The deformation of the respective extension section conveniently includes enlarging the extension section radially.

Conveniently the deformation of the respective extension section is carried out after press fitting the stator onto the at least one pin and further preferably before attaching the rotor assembly

In preferred embodiments, the press fit between the stator and the respective pin is a press fit between the laminated core and the respective pin. That is, the laminated core is used for positioning and fixing the state or to the carrier the respective pin.

In advantageous embodiments, the stator comprises an associated guide for the respective pin. The respective guide extends axially, wherein each guide is axially pressed onto the associated pin to form a press fit. This leads to a more simplified manufacture new more precise positioning and fixing of the state or to the carrier.

Preferably, the laminated core comprises the at least one guide.

According to advantageous embodiments, the lamination core has an associated guide for the respective pin, wherein the respective pin passes through the associated guide. The respective guide extends in an associated axial direction, which is also referred to below as guide axial direction. The respective guide has an associated opening in at least a part of the lamination, wherein the opening is also referred to below as lamination opening. Thus, the respective pin passes through the lamination openings of the associated guide. Here, the lamination core is axially pressed onto the at least one pin to position the stator relative to the carrier and fix the stator to the carrier fix, wherein the respective pin is in contact with the lamination core in an axial contact section of the pin.

In preferred embodiments, in the at least one of the contact sections, preferably in the respective contact section, at least a part of the lamination openings, preferably the respective lamination opening, has at least one tooth. The respective tooth projects radially inward with respect to the associated guide axial direction. The respective tooth extends in a guide circumferential direction of the associated guide over a segment, which is also referred to below as tooth segment, so that, in the associated lamination opening, a gap segment adjoining the tooth segment in the guide circumferential direction is free of teeth. The respective tooth is bent to form the press fit and contacts the associated pin due to the press fit. A clearance segment adjoining the respective tooth in the associated lamination opening in the guide circumferential direction of the associated guide is free of contact with the associated pin and thus distanced to the pin. The projecting teeth result in reliable thermal and electrical contact between the laminated core and the respective pin, so that heat is reliably transported away from the laminated core and thus from the stator via the pins, and the stator is thus reliably cooled. The reliable contact between the laminated core and the pins further results in the laminated core and the pins being electrically equipotential. As a result, there is improved compensation of unwanted electromagnetic interference. At the same time, the locally contact-free arrangement of the lamination to the respective pin and thus the clearance segments lead to a reduction in the forces required when pressing the laminated core onto the pins. As a result, on the one hand the risk of damage to the laminated core is at least reduced, and such damage is in particular avoided. Thus, the aforementioned contacts between the respective lamination and the associated pin are reliably established, as are the clearance sections, so that in turn there is improved cooling and electromagnetic compensation. On the other hand, the reduction of the required forces leads to a simplified and more precise manufacture of the electric machine leading to a further decrease in cycle time in manufacturing the electric machine.

As described above, the respective tooth is bent, when the pin is guided through the associated lamination opening. The teeth and the pins are thus dimensioned accordingly. Thus, the respective tooth is preloaded against the associated pin. On the one hand, this results in reliable contact between the respective tooth and the associated pin, so that thermal dissipation and electromagnetic compensation are implemented more reliably. At the same time, the clearance segments adjacent to the teeth lead to and allow an advantageous deformation of the teeth, so that the contact is improved and precise. On the other hand, reliable relative positioning of the laminated core and thus of the stator to the pins and consequently in the electric machine is thus possible without additional tooling, devices or dedicated positioning features.

The contact of the respective tooth with the associated pin means in the present case an at least substantially continuous contact. The contact can therefore be interrupted locally, for example due to radial recesses in a radial outer side in the contact section of the pin.

The motor axial direction and the guide axial directions are parallel to each other. Consequently, in the present case “axial” means along one of the axial directions.

The axial directions are spaced apart. Thus, “radial” refers in each case to the associated axial direction.

The respective circumferential direction is related to the associated axial direction, that is it revolves around the associated axial direction. This means that the motor circumferential direction is related to the motor axial direction and the respective guide circumferential direction is related to the associated guide axial direction.

The respective guide axial direction is conveniently coaxial with the associated pin. This means that the respective guide axial direction is suitably coaxial with an axis of the associated pin, in particular corresponds to the pin axis.

Preferably, at least one of the guides, preferably the respective guide, is formed in an associated radially projecting tongue of the laminated core, which is spaced apart from the at least one winding/coil of the stator. That is, the respective lamination opening is formed in a radially projecting tongue, in particular in an associated radially projecting tongue, of the associated lamination.

In preferred embodiments, axially successive teeth and gap segments are arranged offset from one another in the guide circumferential direction of the associated guide, so that in an axial plan view of the guide, the teeth of the laminations of the respective guide form a shoulder of the guide that is closed in the guide circumferential direction and projects radially inwards. The shoulder is thus closed in the top view in the guide circumferential direction of the associated guide. That is, the shoulder does not consist of tooth segments connected to each other in the circumferential direction. Such an arrangement of the teeth, and thus the shoulder, has the effect that the respective pin is connected to the laminated core correspondingly in the guide circumferential direction of the associated guide in each angular section. Thus, there is an improved thermal and electrical connection of the laminated core to the respective pin and consequently improved cooling and electromagnetic compensation.

Possible variants are those in which the contact section of at least one of the pins, preferably of the respective pin, has at least one projection which projects radially outwards from the pin with respect to the associated guide axial direction and extends axially. The respective projection is in contact in the contact section with at least two laminations of the associated guide. Thus, the contact between the respective pin and the laminated core is increased. The respective projection conveniently leads to a deformation of the associated laminations. As a result, increased and more reliable contact occurs, so that cooling and electromagnetic compensation are in turn improved.

By definition, the contact between the lamination and the respective projection takes place outside the clearance segments. This means that the respective projection either contacts the respective associated lamination in a tooth segment or interrupts a clearance segment.

The respective projection extends locally in the guide circumferential direction of the associated guide.

Preferably, at least one of the projections, preferably the respective projection, is formed as a radially projecting tip. This results in the respective lamination in contact with the tip being deformed by the tip in such a way that the tip holds and thus secures the lamination axially and about the associated guide circumferential direction. This leads to an increased and improved contact between the laminated core and the pin as well as to an improved and more stable positioning of the laminated core, in particular the stator, on the carrier.

At least one of the projections, in particular the respective projection, can be introduced into the contact section of the associated pin in a spanning manner, for example by means of scoring. This creates a radial recess in the contact section, which results in the projection, in particular the tip. The recess is conveniently spaced from the laminations and thus free of contact to the laminations.

It is possible that at least one of the pins, preferably the respective pin, has at least two such projections, which are spaced apart from one another in the associated guide circumferential direction. Here, at least one projection of the at least one pin can be in contact with a tooth and at least one projection in contact with the lamination outside the tooth segment of at least one of the laminations.

If at least one of the pins has at least one such projection, the associated laminations may each have a single such tooth in the lamination opening.

It is possible that the contact section of at least one of the pins, preferably of the respective pin, is smooth so that only the teeth are in contact with the pin in the contact section. In this variant, the respective gap segment is thus a clearance segment.

If at least one of the pins is smooth as explained, the associated laminations preferably have at least two teeth spaced apart from each other in the associated guide circumferential direction in the associated lamination openings.

The electric machine has a number N of such pins, where N is greater than or equal to two.

Preferably, the electric machine has three such pins, which are preferably arranged equidistantly to each other in the motor circumferential direction. Thus, with a simplified design and thus manufacture of the electric machine, there is a sufficiently high contact between the laminated core and the pins and consequently a sufficiently high cooling and electromagnetic compensation. In addition, the laminated core, preferably the stator, can be reliably and precisely positioned and fixed in this way relative to the carrier and thus in the electric machine.

If the lamination openings each have a single such tooth, the respective tooth segment is preferably 360°/N, that is the respective tooth extends over 360°/N in the associated guide circumferential direction. In addition, an offset of the teeth of the lamination openings of lamination openings of the respective lamination that follow one another in the motor circumferential direction, hereinafter also referred to as opening offset, is advantageously 360°/N with respect to the associated guide circumferential direction. In addition, an offset of the teeth of axially successive lamination openings of the respective guide, hereinafter also referred to as lamination offset, is 360°/N. The said extensions and offsets are conveniently such that the above-described shoulder is formed in the respective guide. For example, if the electric machine has three pins, that is N=3, the respective tooth segment is 120°, that is the respective tooth extends 120° in the associated guide circumferential direction. In addition, the teeth of lamination openings of successive lamination openings of the respective lamination in the motor circumferential direction are 120° offset from each other. In addition, teeth of axially successive lamination openings of the respective guide are offset by 120° from each other.

Preferably, the opening offset and lamination offset are opposite to each other.

The respective lamination opening can have at least two teeth between which a gap segment is arranged in each case. The number M of teeth of the respective lamination opening is therefore greater than or equal to two, M≥2. Preferably, the teeth of the respective lamination opening are spaced apart from each other in the associated guide circumferential direction with a tooth offset of 360°/M. Advantageously, teeth of the lamination openings of successive lamination openings of the respective lamination in the motor circumferential direction are offset from each other with an opening offset with respect to the associated guide circumferential direction, which opening offset is 360°/2M. Preferably, moreover, teeth of axially successive lamination openings of the respective guide are offset with respect to each other with a lamination offset of 360°/N. The said projections are conveniently such that the above-described shoulder is formed in the respective guide.

The number M of teeth of the respective lamination opening can be six, that is M=6.With three pins, that is N=3, this leads to an advantageous variant in which the teeth of the respective lamination opening are spaced apart from one another in the associated guide circumferential direction with a tooth offset of 60°. In addition, teeth of successive lamination openings of the respective lamination in the motor circumferential direction are offset from each other with an opening offset of 30° with respect to the associated guide circumferential direction. Also, teeth of axially successive lamination openings of the respective guide are offset from each other with a lamination offset of 120°.

It is possible to form and manufacture at least two laminations with teeth, each as an individually designed component.

In preferred embodiments, at least two of the lamination of the laminated core having teeth, preferably all lamination of the laminated core having teeth, are designed as identical parts. In this case, the axially successive laminations are rotated relative to each other about the motor axial direction and thus offset in the motor circumferential direction. This offset is also referred to below as row offset.

The row offset is preferably 360°/N. With three pins, that is N=3, axially successive laminations are thus each offset by 120° relative to one another, so that every third lamination has lamination openings with identically oriented teeth.

It is understood that the laminated core can also have laminations which do not have a lamination opening and/or which have lamination openings but do not comprise such a tooth. In particular, it is possible to arrange at least one such lamination at an axial end face of the laminated core. It is likewise possible to arrange at least one such lamination between such laminations with teeth.

As a matter of fact, the scope of the present invention not only covers the electric machine, but also the method for manufacturing of the electric machine.

Further important features and advantages of the invention are apparent from the dependent claims, from the drawings, and from the accompanying figure description based on the drawings.

It is understood that the above features and those to be explained below can be used not only in the combination indicated in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

Preferred exemplary embodiments of the invention are shown in the drawings and will be explained in more detail in the following description, wherein identical reference signs refer to identical or similar or functionally identical components.

DETAILED DESCRIPTION

An electric machine1as shown inFIG.1has a stator2and a rotor3. The electric machine1also has a carrier4to which the stator2is fixed and positioned.FIG.2shows an exploded view in which the carrier4and the stator2can be seen. During operation of the electric machine1, the rotor3rotates relative to the stator2about an axis of rotation R, wherein the axis of rotation R runs parallel, in the shown exemplary embodiments and preferably, coaxial to an axial direction AM of the electric machine1. The axis of rotation R is only indicated inFIG.1. The axial direction AM of the electric machine1is also referred to below as the motor axial direction AM. In the exemplary embodiments shown, the stator2is arranged radially outside the rotor3with respect to the motor axial direction AM and surrounds the rotor3in a circumferential direction CM of the electric machine1, which is also referred to hereinafter as the motor circumferential direction CM. In the exemplary embodiments shown, the rotor3is mounted on the carrier4via a bolt6. The bolt6extends coaxially to the axis of rotation R motor and is fixed to the carrier4.

In the exemplary embodiments shown, the electric machine1is designed as an electric motor1a,the electric motor1abeing used for a fan5. For this purpose, fan blades7of the fan5are connected to the rotor3in a rotationally fixed manner.

The stator2has, as can be seen for example inFIGS.2,3and21, a laminated core8around which at least one winding9of the stator2, visible only inFIG.2, is wound. The laminated core8has laminations10following one another along the motor axial direction AM and thus axially. The lamination10are electrically conductive at least in their core, for example made of silicon steel.

As can be seen, for example, fromFIG.2, the electric machine1has at least one pin11radially offset to the axis of rotation R. In the exemplary embodiments shown, the electric machine1comprises at least two pins11spaced equidistantly from one another in the motor circumferential direction CM.FIGS.12and22show one such pin11. In the exemplary embodiments shown, the electric machine1has three such pins11, so that a number N of the pins11is three, N=3. The pins11are each spaced equidistantly with respect to axis of rotation R and thus with respect to the motor axial direction AM. That is the pins11are arranged along a fictitious circle around the axis of rotation R, which is not shown. The respective pin11is fixed to the carrier4. In the exemplary embodiments shown, the respective pin11is overmolded by the carrier4. That is, the respective pin11is inserted in an injection mold and is overmolded with the material of the carrier4. The bolt6may be fixed to the carrier4in the same manner. In the exemplary embodiments and preferably, carrier4and pins11are each manufactured at least in their core of an electrically conductive material. For example, the carrier4can be made of aluminum and the pins11of steel. The respective pin11extends axially and thereby projects from the carrier4. The stator2is axially pressed onto the at least one pin11so that the stator2is positioned relative to the carrier2and fixed to the carrier2. That is, the stator2is attached to the respective pin11by means of a press fit and so that the at least one press fit positions the stator2relative to the carrier4and fixes the stator2to the carrier4. In the exemplary embodiments shown the laminated core8is pressed onto the respective pin11for form said press fits. That is, positioning and fixing of the stator2the carrier4is carried out using the laminated core8. In addition, said fixing and positioning is free of screw connections. This allows additional simplification of the manufacture of the electric machine1and a further decrease in the cycle time during manufacture.

In the exemplary embodiments shown the laminated core8has an associated guide12for the respective pin11through which the pin11passes, as can be seen, for example, from a synopsis ofFIGS.2to4. In the exemplary embodiments shown, the laminated core8thus has three such guides12. The respective guide12extends along an associated axial direction AG, which is also referred to hereinafter as guide axial direction AG. The respective guide axial direction AG thus runs parallel to the motor axial direction AM, so that all axial directions AM, AG run parallel to one another. The guide axial directions AG are radially spaced in accordance with the arrangement of the pins11with respect to the motor axial direction AM and are arranged equidistantly with respect to one another along the motor circumferential direction CM. The respective guide12has an associated opening13in at least a part of the laminations10, in the shown exemplary embodiment in the respective lamination10, which will also be referred to hereinafter as lamination opening13. Thus, the respective pin11passes through the lamination openings13of the associated guide12.

For manufacturing the electric machine1, a carrier assembly25, a stator assembly26and a rotor assembly27may be provided, as indicated inFIGS.1and2. The carrier assembly25comprises the carrier4and the at least one pin11fixed to the carrier4. In the exemplary embodiments shown, the carrier assembly25further comprises the bolt6fixed to the carrier4. The stator assembly26comprises the stator2at least partially. The stator assembly26, in the exemplary embodiments shown, comprises at least the laminated core8. The rotor assembly27comprises the rotor3at least partially. The rotor assembly27is not shown inFIG.2for better overview. Further, inFIG.2the pins are shown distanced to the carrier4. As an arrow indicates inFIG.2, the stator assembly26is axially press fitted onto the carrier assembly25by press fitting the laminated core8onto the at least one pin11, such that the stator assembly26is positioned and fixed to the carrier4. The rotor assembly27is rotatably fixed to the carrier4using the bolt6.

As will be explained below, in the exemplary embodiments shown, the respective pin11is in contact with lamination10of the laminated core8within an axially extending contact section14of the pin11(see alsoFIGS.12and22). In the contact section14, at least some of the lamination openings13each have at least one tooth15projecting radially inward with respect to the associated guide axial direction AG. The respective tooth15is bent to form associated press fit. That is, the respective tooth16is bent due to the associated press fit. In the exemplary embodiments shown, in the contact section14the respective lamination opening13has at least one tooth15projecting radially inwards with respect to the associated guide axial direction AG.FIGS.4and16each show a top view of a lamination10with lamination openings13, which each have at least one such tooth15. As shown inFIGS.4and16, the respective tooth15extends in a circumferential direction CD of the associated guide12, hereinafter also referred to as guide circumferential direction CG, over a tooth segment16. Thus, a gap segment17adjoining in guide circumferential direction CG in the associated lamination opening13is free of teeth15. As can be seen, for example, fromFIGS.13,14as well as23, the respective tooth15contacts the associated pin11. In addition, the lamination opening13is spaced apart from the associated pin11in a clearance segment18following the respective tooth15of the associated lamination opening13in the guide circumferential direction CG of the associated guide12and is thus free of contact to the pin11.

As described before, the laminated core8is pressed onto the pins11so that a press fit is produced between the laminated core8and the pins11. Due to the described clearance segments18, the force required for the press fit is reduced, so that the manufacture of the electric machine1can be simplified and precise and with decreased cycle time. At the same time, the clearance segments18allow a defined deforming of the teeth15, so that there is a reliable electrical and thermal contact between the laminated core8and the pins11. Consequently, heat can be transferred from the laminated core8to the pins11and via the pins11to the carrier4in a reliable and improved manner. Thus, improved cooling of the laminated core8and consequently of the stator2is achieved. In the exemplary embodiments shown, the carrier4further has axially projecting ribs19for improved thermal dissipation, as can be seen fromFIG.2. The carrier4is grounded by means of an electrical connection, as indicated inFIG.1. Thus the pins11are also grounded. The reliable electrical contact of the teeth15with the pins11provides a more reliable grounding of the laminated core8. Thus, undesired electromagnetic interference in the laminated core8can be reduced/compensated in a simplified manner. As a result, the operation and the electromagnetic compensation and compatibility of the electric machine1are improved.

In the exemplary embodiments shown inFIGS.3to15, the respective lamination opening13has a single tooth15, as can be seen from a synopsis ofFIGS.4to7.FIGS.5to7each show enlarged views of one of the lamination openings13of the lamination10shown inFIG.4. In these exemplary embodiment, the respective tooth15extends over 120° in the associated guide circumferential direction CG, so the tooth segment16is 120°. In other words, the tooth segment is 360°/N, where the number N of pins3and thus guides12is three, as explained above. As can further be seen fromFIGS.4to7, the teeth15of successive lamination openings13of the respective lamination10are offset with respect to each other with an offset with respect to the associated guide circumferential direction CG, which offset is hereinafter also referred to as the opening offset. The opening offset is 120°, that is 360°/N.FIG.8shows axially successive lamination openings13of a guide12. As can be seen fromFIG.8, in the exemplary embodiments shown inFIGS.3to15, the teeth15of axially successive lamination openings13of the respective guide12are offset from one another with respect to the associated guide circumferential direction CG, which offset is also referred to below as lamination offset. The lamination offset is 360°/N, that is 120°. As can be seen from a synopsis ofFIGS.4to8, the opening offset and the lamination offset are in opposite to each other. As indicated inFIG.9, an axial top view of the respective guide12thus results in a shoulder20, which projects radially inwards with respect to the associated guide axial direction AG and is closed in the associated guide circumferential direction CG. The teeth15of the lamination openings13of the respective guide12are thus offset relative to one another in such a way that such a shoulder20is formed. InFIG.9, one of the teeth15is shown with a solid line and the other teeth15are shown with different dashed lines to make it clear that the shoulder20is composed of teeth15that are axially offset from one another.

In the exemplary embodiment ofFIGS.16to23, the respective lamination opening13has at least two teeth15. The number M of teeth15of the respective lamination opening13is therefore at least two, M≥2. In the exemplary embodiment shown, the respective lamination opening13has six teeth15, that is M=6. The teeth15of the respective lamination opening13are arranged equidistantly to one another in the associated guide circumferential direction CG. In the exemplary embodiment shown, therefore, pairs of teeth15are arranged radially opposite each other in the respective lamination opening13with respect to the associated guide axial direction AG. The teeth15of the respective lamination opening13are also spaced apart from one another by gap segments17in the associated guide circumferential direction CG.FIGS.17to19each show an enlarged view of one of the lamination openings13of the lamination10shown inFIG.16. As can be seen from a synopsis ofFIGS.16to19, in the exemplary embodiment shown inFIGS.16to23, the teeth15of the respective lamination opening13are spaced apart from one another in the associated guide circumferential direction CG with an offset, which is also referred to hereinafter as tooth offset. The tooth offset thus corresponds to the extension of the respective gap segment17in the associated guide circumferential direction CG. In the exemplary embodiment shown, the tooth offset is 60°, that is 360°/M. Furthermore, the opening offset, that is the offset of the teeth14of successive lamination openings13of the respective lamination10in the motor circumferential direction AM, is 20°, that is 360°/2M, with respect to the associated guide circumferential direction CG.FIG.20shows axially successive lamination openings13of one of the guides12. As can be seen in particular fromFIG.20, the teeth15of axially successive lamination openings13of the respective guide12are offset with respect to each other by a lamination offset of 120°, that is 360°/N. Thus, in axial not shown plan view, a not shown shoulder20of the type described above may result for the respective guide12.

In the exemplary embodiments shown, the laminations10of the laminated core8having teeth15are formed as identical parts24. In this case, axially successive laminations10are arranged rotated relative to one another about the motor axial direction AM, that is with an offset in the motor circumferential direction CM. This offset, which is also referred to below as row offset, is 120°. The row offset is therefore 360°/N.

As shown inFIGS.10to12, the respective pin12may have in the associated contact section14at least one projection21projecting radially outward with respect to the associated guide axial direction CG.FIG.10shows a radial section through the pin11andFIG.11shows an enlarged view ofFIG.10in the region of such a projection21, andFIG.12shows a spatial view of the pin12. As can be seen fromFIG.12, the respective projection21extends axially, in the shown exemplary embodiment over the entire extension of the contact section14. As can be seen in particular fromFIG.11, the projection21in the shown exemplary embodiment and preferably is formed as a radially projecting tip22. The respective projection21, in particular the respective tip22, in the shown exemplary embodiment is introduced in a spanning manner, in particular by means of scoring, into the pin11, so that a depression23is formed adjacent to the projection21, in particular the tip22. As can be seen from a synopsis ofFIGS.10and12, the pin11in the exemplary embodiment shown has four such projections21, which are arranged equidistantly to one another in the associated guide circumferential direction CG, that is two of the projections21are arranged radially opposite one another in each case.

In the exemplary embodiment shown inFIG.22, the pin11is smooth in the contact section14, that is in particular free of projections21and recesses23of the type described above. In this exemplary embodiment, the respective gap segment17thus corresponds to a clearance segment18(seeFIG.23). The pin11shown in the exemplary embodiment ofFIG.22is used exemplarily in the exemplary embodiments shown inFIGS.16to23.