DE102013004057B4 - Device for an electric machine - Google Patents

Abstract

Apparatus for an electric machine, comprising: a stator having a stator support (611, 1711) and at least one stator tooth (613, 1713) extending in an axial direction (203-1803) and at an axial end of the stator tooth (613, 1713) terminates at a first axial position (621, 1721); anda rotor having at least one permanent magnet (619, 1719), wherein the rotor relative to the stator about an axis of rotation in the axial direction (203-1803) at a first axial distance between the stator and the rotor and at a second axial distance ( d2) is rotatable between the stator and the rotor, wherein the rotor and / or the stator is in each case formed by a first part (305a, 301a) and a second part (305b, 301b) which are arranged mirror-symmetrically, a mirror plane ( 325-1825) is oriented perpendicular to the axis of rotation and spaced from the first axial position (621, 1721), wherein the first part (305a, 301a) and the second part (305b, 301b) each have a first axial distance between the rotor and the stator and a second axial distance (d2) between rotor and stator are assigned, wherein in each case starting from the first axial distance of the first part of the rotor and the second part of the rotor in opposite axial directions of the mirror plane 325-1825) are moved away to reach the respective second axial distance (d2), wherein the following features are realized: the stator support (611, 1711) protrudes axially beyond the first axial position (621, 1721) axially outwards of the stator tooth (613, 1713) and the permanent magnet (619, 1719) projects axially beyond the first axial position (621, 1721) axially outward of the axial distance between the stator and the rotor where the rotor is rotatable relative to the stator Statorzahns (613, 1713) addition.

Description

Embodiments of the present invention relate to an apparatus for an electric machine having a permanent magnet and which allows to reduce an overlap amount between the stator and a rotor having the permanent magnet to enable field weakening in an increased speed range.

Permanent magnetically excited electric machines, such as electric motors or generators, have one or more permanent magnets, which may be arranged in a circumferential direction spaced from one another, as exciters for generating a magnetic field. When rotating relative to the stator windings stator, the permanent magnets induce electrical voltages in the stator windings. At high speeds it may be necessary to weaken this magnetic excitation field because of the limited supply voltage, which may be supplied by a battery, for example, so as to maintain an induced voltage below the supply voltage. Conventionally, for example, a mechanical field weakening has been proposed, whereby the magnetic field generated by the permanent magnets and coupled to the stator windings is weakened by achieving a reduction of the axial overlap or overlap between stator and rotor in a mechanical manner, for instance by displacement.

JP 2005 - 253 265 A discloses a permanent magnet synchronous motor wherein the stator or rotor is provided with an axially movable displacement mechanism to allow a coupling flux area to be reduced.

JP 2007 - 129 869 A discloses a permanent magnet motor, wherein a relative displacement between stator and rotor is made possible to control a voltage can.

EP 1 936 785 B1 discloses a self-regulating permanent magnet apparatus wherein the rotor includes two rotor segments connected to spring members for maintaining rotational alignment between two sets of permanent magnets disposed on the respective rotor segments, further wherein a reactant based on a rotational speed is a reaction torque generates, which counteracts the spring force and generates an offset of the two sets of permanent magnets, so that an electromotive force generated in the stator windings of the stator is regulated.

DE 10 2010 002 401 A1 discloses a rotary electric machine, wherein the rotor is bisected in the direction of its rotary shaft, wherein a variation of positions of field magnets, which are arranged on the two parts of the rotor, is made possible.

DE 10 2006 036 986 A1 discloses an electric motor with a mechanical field weakening device, wherein a stator is arranged axially displaceable relative to the rotor, so that an active conductor length of a stator winding, which is located in the exciting field of the rotor, is variable.

US Pat. No. 6,771,000 B2 discloses a rotary electric machine and a power generation system wherein a first field magnet is axially displaced relative to a second field magnet.

US Pat. No. 6,664,694 B2 discloses a rotor-axial activation modulation system having a centrifugally generating axial drag structure and a preloaded spring wherein the rotor of the electric machine is modulated to produce a corresponding axial displacement.

DE 602 19 096 T2 discloses a dynamoelectric machine in which field weakening of the magnetic flux generated by permanent magnets is made possible, wherein a rotor has two field magnets, which are displaceable in the direction of rotation of the rotary shaft, which displacement is controllable in accordance with an induced electromotive force.

WO 2009/004 633 A2 discloses a generator which allows to control the length of the stator and / or the rotor, wherein the length of the stator and / or the rotor winding is controlled according to the rotational speed of the shaft of the generator, wherein a relative position of the stator winding relative to a position of the Rotor winding is adjusted.

US 2007/0 241 628 A1 shows an embodiment of an electric machine with a stator core carrying a winding and having stator teeth. The rotor has permanent magnets and is rotatable about an axis of rotation relative to the stator. In this case, permanent magnets can assume two positions with their carriers in the axial direction relative to the stator.

JP 2010 - 206 952 A relates to an electric machine having a stator with a stator tooth and a rotor with permanent magnets, wherein the rotor relative to the stator about a rotational axis extending in the axial direction at a first and a second axial distance between the Stator and the rotor is rotatable. The stator yoke protrudes beyond the area of the stator tooth.

GB 2 056 725 A discloses a hydraulic Verstellaktorik in an electric machine for the rotor. There is a protrusion between the rotor and the stator. It is not described or apparent from the drawings that also survive the permanent magnets of the rotor.

It has been observed that field weakening can not be achieved in all situations in an advantageous manner and / or is associated with performance losses. In particular, a performance or power density of conventional electric machines with mechanical field weakening is unsatisfactory and / or conventional electric machines have undesirable losses.

Object of the present invention is to provide an apparatus for a permanent magnet electric machine, which achieves a field weakening in a simple and effective manner, wherein a performance or power density of the electric machine, compared to conventional electric machines, is increased and / or whereby losses compared to conventional electric machines are reduced.

Embodiments of the present invention may be based on the recognition that a mechanical field weakening by stray fields in the field weakening region may be limited. In order to improve the field wearability of the electric machine, a novel design of rotor and / or stator and / or winding of the stator is proposed according to embodiments of the present invention.

Furthermore, embodiments of the invention can be based on the recognition that a mechanical field weakening is associated with additional losses and that, if these additional losses are taken into account in the design phase, the losses can be significantly reduced. In particular, it has been found by the inventors that losses associated with winding heads of the stator windings can occur, in particular because of axial fields and because of conductive structural parts. Embodiments are directed to reducing the losses due to axial fields and / or the losses on the conductive structural members in order to minimize these parasitic losses in the mechanical field weakening region, that is, at increased rotational speeds. Also, the losses can be reduced, according to embodiments of the present invention, by novel stator / rotor / winding designs.

Embodiments of the present invention are directed to a permanently energized electric machine, wherein an improvement of the field weakenability and / or a reduction of additional losses can be achieved.

According to an embodiment of the present invention, there is provided an apparatus for an electric machine, such as an electric motor or a generator, having a stator and a rotor. The stator, which may represent about a circumferential portion or a circumferential segment or may represent an entire circumference of the electric machine, has a stator support and at least one stator tooth (which is connected to the stator), wherein the stator tooth extends in an axial direction and on an axial end of the stator tooth terminates at a first axial position. The rotor has at least one permanent magnet which, in particular at least in an operating state of the device, is inductively coupled to a stator winding, which may be provided on the stator. In this case, the rotor is rotatable relative to the stator about an axis of rotation extending in the axial direction at a first axial distance between the stator and the rotor and at a second axial distance between the stator and the rotor. Further, in the apparatus for an electric machine, at least one of the following features is realized: the stator support protrudes radially beyond the first axial position axially outward of the stator tooth, and the permanent magnet protrudes both in the case of the first axial distance and in the case of the second axial distance axially beyond the first axial position axially outward of the stator tooth. In an axial distance can be understood in embodiments, an axial offset.

In particular, a permanently excited electric motor can be constructed with the device for an electric machine. The stator, in particular including the stator carrier and the stator tooth, may be made of a magnetically highly permeable material to concentrate a magnetic field in an electric current flow through stator windings generated magnetic field within the stator, so that in particular the magnetic field generated in a gap between the stator and permanent magnets exit to couple with a magnetic field generated by the permanent magnet, which can also extend into the gap. The rotor may be embodied as an inner rotor or as an outer rotor. If the rotor is designed as an inner rotor, the stator carrier may be located radially outside of the stator tooth. When the rotor is configured as an outer rotor, the stator carrier may be located radially inside the stator tooth. The stator and the stator carrier and the stator tooth may each have two axial ends. In any case, at an axial end of the stator tooth (or at both axial ends of the stator tooth) of the stator tooth (each) ends at a certain axial position, in particular the stator tooth ends at an axial end at a first axial position, at the other axial end of the stator tooth, the stator tooth at another first axial position end.

The first axial distance or the second axial distance between the stator and the rotor can be defined in various ways. In particular, both the stator and the rotor can be assigned certain axial positions, starting from which an axial distance can be defined. In particular, an axial positioning of the stator and / or the rotor can be defined in each case by a center of gravity position of the stator or of the rotor in the axial direction. Alternatively, for example, an axial position of the stator or rotor may be defined by an axial position at one end of the stator or rotor, or an axial position of the stator or rotor may be an axial position of any (fixed) location within the stator or rotor . of the rotor. The first axial distance or the second axial distance between the stator and the rotor can then be defined as a (signed) difference between the axial position of the stator and the axial position of the rotor.

The first axial distance between the stator and the rotor may be associated with a first relative axial overlap between the stator and rotor and the second axial distance between the stator and the rotor may in particular be associated with a second relative axial overlap between stator and rotor. The first axial overlap may in particular be different from the second axial overlap. The second axial overlap may in particular be smaller than the first axial overlap. In particular, the second axial overlap can be adjusted if, during operation of the electric machine, a rotational speed of the rotor exceeds a rotational speed threshold, in such a situation or in such an operating mode a field weakening of an effectively acting between rotor and stator magnetic field or magnetic flux to reach.

In particular, the first axial distance between the stator and the rotor may be associated with a first axial relative position or relative position with respect to the stator and the rotor and the second axial distance between the stator and the rotor may be a second axial relative position or relative position with respect to Stators and the rotor to be assigned. An axial relative displacement between the rotor and the stator can be made possible in order to be able to set the first axial distance or the second axial distance between the stator and the rotor. The relative axial displaceability may be provided by mechanical and / or electromechanical and / or electrical mechanisms, including e.g. a spring, an electric motor, a centrifugal force control system, be realized.

The stator support may protrude axially beyond the first axial position axially outwardly of the stator tooth by an equal length to or beyond a length other than the permanent magnet. The permanent magnet can thus axially over the first both in a normal operating mode of the electric machine (which may correspond to the first axial distance between the rotor and stator) and in an operating state at elevated speed (which may correspond to the second axial distance between the rotor and stator) Axial position after axially protrude outside the stator tooth. The protrusion of the stator carrier axially beyond the first axial position axially outward of the stator tooth may also be referred to as a stator carrier overhang. The protrusion of the permanent magnet axially beyond the first axial position axially outward of the stator tooth may also be referred to as a permanent magnet overhang (or rotor overhang for short). Stator carrier overhang and / or permanent magnet overhang can be realized individually or in combination. Thus, an improvement of the field weakenability of the electric machine can be achieved.

The rotor and / or the stator can be designed as a one-piece element, that is to say a one-piece rotor or one-part stator, or as a two-part element, that is to say a two-part rotor or two-part stator. In particular, mechanical field weakening may be provided with a one-piece rotor or with a two-piece rotor by displacement relative to the stator. At the first axial distance between stator and rotor, an active length (and in particular axial overlap) of the electric machine may be greater than at the second axial distance between the stator and the rotor, wherein the excitation field is not directly proportional to the active length of the electric Machine can be weakened.

According to the present invention, at each axial distance between the stator and the rotor, in which the rotor is rotatable relative to the stator, the permanent magnet protrudes axially beyond the first axial position axially outwardly of the stator tooth. Thus, a permanent magnet overhang not only in the increased speed range in which a field weakening is to be achieved, but also be given in the normal speed range. In particular, the device may be such be configured that it is not possible to achieve no permanent magnet overhang. There may be more noise or stray fields in the normal speed range than if there is no permanent magnet overhang. However, a change in the interference fields or stray fields, when setting the second axial distance between the stator and the rotor, may be smaller, although there is a permanent magnet overhang in the normal speed range, compared to the case in which there is no permanent magnet overhang in the normal speed range. Thus, a field weakening can be improved.

Due to a stator overhang and / or a rotor overhang, winding heads of stator windings can be involved in the formation of torque. In particular, stray fields can be amplified and participate in the formation of torque.

According to the present invention, the rotor and / or the stator are each formed by a first part and a second part, which are arranged mirror-symmetrically, wherein a mirror plane is oriented perpendicular to the axis of rotation and spaced from the first axial position, in particular the first part of the stator and the second part of the stator may each have a first axial position (each corresponding to an axial end of the stator tooth) may be assigned. In this case, the first part and the second part are each assigned a first axial distance between the respective part of the rotor and stator and a second axial distance between the respective part of the rotor and the stator. Furthermore, in each case starting from the first axial distance, the first part of the rotor and the second part of the rotor can be moved away in opposite axial directions from the mirror plane in order to reach the respective second axial distance. Thus, in particular between a first part of the rotor and the stator, a first axial distance can be made possible and between the second part of the rotor and the stator can also be achieved a first axial distance or a first axial overlap. Furthermore, a second axial distance or a second axial overlap can be achieved between the second part of the rotor and the stator and also between the second part of the rotor and the stator, a second axial distance or a second axial overlap can be achieved. Thus, a field weakening can be realized in a simple manner. Furthermore, an electric machine with a two-part rotor or a two-part stator can thus be improved by a rotor overhang and / or a stator overhang with regard to field weakenability and reduction of losses.

According to an embodiment of the present invention, the device further comprises an electrical conductor which extends in the circumferential direction adjacent to the stator tooth, in a first axial region in the axial direction along the stator tooth and in a second axial region, which lies axially outside of the stator tooth, at least partially forms a winding head. The first axial region may extend in particular from the first axial position axially within the stator tooth, and the second axial region may extend in particular from the first axial position to axially outside the stator tooth. The electrical conductor may in particular at least partially form a stator winding. In particular, the stator may be provided with a plurality of electrical conductors, which may form a plurality of stator windings. By providing a rotor overhang and / or stator overhang, the winding head, which is arranged in the second axial region, can be involved in particular in torque formation. Thus, a performance of the electric machine can be improved or a torque generation can be increased.

According to one embodiment of the present invention, the conductor in the winding head is at least partially surrounded, in particular embedded and / or cast in by an embedding material which has a relative magnetic permeability of> 1, in particular between 1 + 0.4 × 10 ^-6 and 50, wherein the embedding material in particular adjacent to the axial end of the stator tooth and / or in particular axially adjacent to the outside of the stator tooth to the stator. The potting material may result in magnetic field or magnetic flux focusing to increase coupling between the stator and rotor. Thus, performance characteristics of the electric machine can be improved. The relative magnetic permeability of the embedding material may in particular be greater than that of air, in particular under normal conditions, such as a temperature of 20 ° C and an air pressure of about 1 bar. The conductor may be cast in particular in the region of the winding head of the embedding material. The embedding material may be formed of a ferromagnetic material-containing powder and a resin. The embedding material may be liquid during processing and may later be in a solid state (such as after polymerization). The embedding material may in particular be in contact with the axial end of the stator tooth and / or in contact with the stator carrier. Due to the embedding material, a torque formation can be improved, and in particular a proportion of the torque due to the winding head can be improved by a winding head casting by means of the embedding material.

According to an embodiment of the present invention, the winding head has a axially inner end coinciding with the first axial position and an axially outer end coinciding with an axial position up to which the permanent magnet protrudes in the case of the first axial distance and / or to the stator carrier axially beyond the first axial position protrudes axially outside of the stator tooth. Other embodiments allow various permanent magnet overhangs and / or stator overhangs or Statorträgerüberhänge, which lie approximately axially outside of an axially outer end of the winding head. Thus, a compact electric machine can be provided which can improve field weakening.

According to an exemplary embodiment of the present invention, the electrical conductor in the first axial region, which extends from the first axial position within the stator tooth, is arranged completely in a first radial region and the electrical conductor is in the second axial region, which is outside the first axial position Statorzahns arranged in a second radial region which comprises at least a partial radial region which does not overlap with the first radial region, wherein the partial radial region is arranged radially further away from the rotor than the first radial region. In particular, therefore, the winding head can be arranged radially, at least partially, further away from the rotor than the electrical conductor axially within the stator tooth. The winding head or the electrical conductor can in particular be formed, shaped or curved such that it is arranged as far as possible (in the winding head region) away from the rotor. Thus, additional losses, which may occur especially at the second axial distance between the rotor and stator can be reduced.

According to an exemplary embodiment of the present invention, the electrical conductor in the second axial region has a bend, in particular between 70 ° and 90 °, away from the rotor. This can be achieved that at least a portion of the electrical conductor (in particular in the winding head region) is arranged as far away from the rotor. Thus, additional losses in the field weakening speed range can be reduced.

According to an exemplary embodiment of the present invention, the electrical conductor in the second axial region has at least one section (or a plurality of sections) whose longitudinal direction is radially oriented and / or a section (or a plurality of sections) which is both a radially oriented component and having an axially oriented component.

In particular, a winding designated as an end winding or a winding of the electrical conductor designated as a conical jacket winding can thus be achieved in order to be able to dispose at least part of the winding head as far as possible (in the radial direction) from the rotor. Thus, additional losses, in particular in the field weakening range, in which the second axial distance between the stator and the rotor is set, can be reduced.

According to an embodiment of the present invention, in the case of the second axial distance, a smaller axial overlap (or overlap) between rotor and stator is achieved than in the case of the first axial distance, wherein the first axial distance in a first speed range and the second axial distance in a second speed range, which is higher than the first speed range, are adjustable in order to achieve field weakening (in particular magnetic field weakening or weakening of a coupling between stator and rotor) in the second speed range, so that an operating-induced voltage (which in particular in the stator windings generated may be smaller than a supply voltage of a stator winding (which stator winding is in particular at least partially formed by the electrical conductor). In particular, an active length of the electric machine may be smaller at the second axial distance between the stator and the rotor than at the first axial distance between the stator and the rotor.

Thus, the electric machine can be operated to be supplied with a supply voltage source of a limited level of a supply voltage, such as a battery.

According to an embodiment of the present invention, in the case of the first axial distance, the permanent magnet extends for a first length and, in the case of the second axial distance for a second length greater than the first length, axially beyond the first axial position axially outward of the stator tooth , Further, according to this embodiment, the stator support extends axially beyond the first axial position axially beyond the stator tooth by a third length, the first length being smaller than the third length, the second length being greater than the third length, the second length being especially similar to an axial extent of the winding head. Thus, a field weakening can be improved and additional losses can be reduced in particular.

According to an embodiment of the present invention, the apparatus for the electric machine further comprises a rotor back-up structure co-rotating with the rotor, which is disposed axially outside the permanent magnet when the second axial distance is taken is. The rotor yoke structure may be formed of a magnetically highly permeable material and, in particular, may perform a function of returning a magnetic field generated by the permanent magnet into the rotor by concentrating magnetic field lines within the rotor yoke structure to prevent or prevent magnetic field leakage. to reduce it, that the magnetic fields or magnetic fluxes generated by the permanent magnet interact with other components that do not rotate with the rotor, such as components axially adjacent to the rotor, such as a housing. Thus, a loss can be reduced, which can increase a performance of the electric machine.

According to one exemplary embodiment of the present invention, the rotor further has a carrier (also called a rotor carrier) (which in the case of an inner rotor, in particular radially inside the permanent magnet and which in the case of an outer rotor can be arranged in particular radially outside the permanent magnet) the permanent magnet is mounted (in particular such that the permanent magnet represents an outer surface of the rotor), wherein the rotor yoke structure is at least partially formed by the carrier, wherein the carrier axially outside of the permanent magnet in particular, at least partially, has a rectangular cross-sectional shape.

In particular, the carrier may thus protrude or protrude axially outwardly of the permanent magnet, thus allowing magnetic field lines of a magnetic field, which is generated by the permanent magnet, to be drawn back into the rotor. In particular, a magnetic field generated by the permanent magnet, in particular at an axial end of the permanent magnet, magnetic field lines having at least partially axial component. Due to the rotor yoke structure, which is formed axially outside of the permanent magnet by the rotor carrier, these magnetic field lines or magnetic fields aligned in this way can be guided back into the rotor in order to prevent undesired interaction with axially adjacent components of the rotor or electric machine thus reducing the additional loss.

According to an embodiment of the present invention, the carrier tapers in its radial extent with increasing axial distance from the permanent magnet, in particular in a linear manner. In cross-section, an axially outside of the permanent magnet disposed part of the carrier may have a triangular shape (at least partially). This can improve a return of magnetic flux into the rotor. In particular, the carrier may have axially outside the permanent magnet a same radial level or a different radial level compared to a radial level of a surface of the permanent magnet. Furthermore, a level of the (rotor) carrier in the radial direction may assume different values axially outside the permanent magnet, in particular the radial level of the carrier of the rotor may be lower axially outside the permanent magnet (over a certain axial area) than in an axially more distant portion from the permanent magnet. This portion of the carrier radially outward of the permanent magnet, which has a radial level which is lower than a radial level of the permanent magnet, can form a gap or a notch. Dimensions of a radial level of the carrier radially outside the permanent magnet or dimensions of an axial extent of the carrier radially outside of the permanent magnet and / or the gap can be optimized according to simulations. An expansion of an axial overhang of the rotor carrier beyond an axial end of the permanent magnet can also be optimized by simulations. Also, a form of taper of the carrier beyond the end of the permanent magnet can be optimized by simulation.

According to an embodiment of the present invention, the rotor yoke structure comprises a disk (in particular circular disk) which is arranged in a plane perpendicular to the axis of rotation and is connected to the rotor. The disk may also be referred to as a permanent magnet shorting disk. In particular, the disk can reduce penetration of magnetic fields generated within the electric machine into surrounding elements such as a housing. In particular, the disk can be designed as a rotor bell, so that it can (at least partially) surround the stator (in particular in the case of an external rotor), in particular together with the rotor. The disc can be provided both for a one-piece rotor and for a two-part rotor, wherein in the case of the two-part rotor in each case a portion of the rotor, a disc may be mounted.

• 1 illustriert eine beispielhafte Kennlinie einer Elektromaschine, welche gemäß einem Ausführungsbeispiel der vorliegenden Erfindung berücksichtigt wird;
• 2 illustriert in einer schematischen Querschnittsansicht einer Permanentmagnet-erregten Elektromaschine gemäß einem Ausführungsbeispiel der vorliegenden Erfindung;
• 3A, 3B illustrieren in schematischer seitlicher Schnittansicht eine Elektromaschine;
• 4A, 4B, 4C illustrieren in schematischer seitlicher Schnittansicht eine Elektromaschine in verschiedenen Betriebsmodi;
• 5 illustriert eine Kennlinie einer Elektromaschine gemäß einem Ausführungsbeispiel der vorliegenden Erfindung, welche gemäß einem Ausführungsbeispiel der vorliegenden Erfindung berücksichtigt wird;
• 6A, 6B illustrieren in schematischer seitlicher Schnittansicht eine Elektromaschine gemäß einem Ausführungsbeispiel der vorliegenden Erfindung;
• 7 illustriert eine magnetische Flussverteilung in einer Elektromaschine; ;
• 8 illustriert in seitlicher schematischer Schnittansicht eine Elektromaschine;
• 9A, 9B, 9C illustrieren schematisch Geometrien eines elektrischen Leiters in einem Wickelabschnitt einer Statorwicklung, welche in einer Elektromaschine gemäß einem Ausführungsbeispiel der vorliegenden Erfindung eingesetzt werden kann;
• 10 illustriert in schematischer seitlicher Schnittansicht eine Elektromaschine bzw. einen Teil einer Elektromaschine;
• 11A, 11B illustrieren in schematischer seitlicher Schnittansicht eine Elektromaschine in verschiedenen Betriebsmodi;
• 12A, 12B, 12C, 12D illustrieren Ausführungsbeispiele einer Elektromaschine, welche eine Rotorrückschlussstruktur umfassen;
• 13 illustriert in schematischer seitlicher Schnittansicht eine Elektromaschine bzw. einen Teil einer Elektromaschine mit einer Rotorrückflussscheibe;
• 14 illustriert in schematischer seitlicher bzw. axialer Schnittansicht eine Elektromaschine bzw. einen Teil einer Elektromaschine;
• 15 illustriert in den Teilansichten 15A, 15B, 15C Elektromaschinen, welche eine Permanentmagnet-Kurzschlussscheibe umfassen;
• 16 illustriert in den Teilansichten 16A bis 16H Elektromaschinen;
• 17A, 17B illustrieren eine Elektromaschine in zwei verschiedenen Betriebsmodi gemäß einem Ausführungsbeispiel der vorliegenden Erfindung und
• 18A, 18B illustrieren in schematischer seitlicher Schnittansicht eine Elektromaschine in zwei verschiedenen Betriebsmodi.

Embodiments of the present invention will now be explained with reference to the accompanying drawings. The invention is not limited to the illustrated or described embodiments.

• 1 illustrates an exemplary characteristic of an electric machine that is taken into account according to an embodiment of the present invention;
• 2 illustrated in a schematic cross-sectional view of a permanent magnet-excited electric machine according to an embodiment of the present invention;
• 3A . 3B illustrate in schematic side sectional view an electric machine;
• 4A . 4B . 4C illustrate in schematic side sectional view an electric machine in various modes of operation;
• 5 illustrates a characteristic of an electric machine according to an embodiment of the present invention, which is taken into account according to an embodiment of the present invention;
• 6A . 6B illustrate in schematic side sectional view an electric machine according to an embodiment of the present invention;
• 7 illustrates a magnetic flux distribution in an electric machine; ;
• 8th illustrates in lateral schematic sectional view of an electric machine;
• 9A . 9B . 9C schematically illustrate geometries of an electrical conductor in a winding section of a stator winding, which can be used in an electric machine according to an embodiment of the present invention;
• 10 illustrates in schematic side sectional view an electric machine or a part of an electric machine;
• 11A . 11B illustrate in schematic side sectional view an electric machine in various modes of operation;
• 12A . 12B . 12C . 12D illustrate embodiments of an electric machine comprising a rotor yoke structure;
• 13 11 illustrates, in a schematic side sectional view, an electric machine or a part of an electric machine with a rotor return flow disk;
• 14 illustrates in schematic side or axial sectional view of an electric machine or a part of an electric machine;
• 15 illustrated in the partial views 15A . 15B . 15C Electric machines comprising a permanent magnet shorting disc;
• 16 illustrated in the partial views 16A to 16H Electrical machinery;
• 17A . 17B illustrate an electric machine in two different modes of operation according to an embodiment of the present invention and
• 18A . 18B illustrate in schematic side sectional view an electric machine in two different operating modes.

Various embodiments will now be described in more detail with reference to the accompanying drawings, in which some embodiments are illustrated. In the figures, the thickness dimensions of lines, layers and / or regions may be exaggerated for the sake of clarity.

Although embodiments may be modified and changed in various ways, exemplary embodiments are illustrated in the figures as examples and will be described in detail herein. It should be understood, however, that it is not intended to limit embodiments to the particular forms disclosed, but that embodiments are intended to cover all modifications, equivalents, and alternatives that are within the scope of the invention. Like reference numerals designate like or similar elements throughout the description of the figures.

Note that an element referred to as being "connected" or "coupled" to another element may be directly connected or coupled to the other element, or intervening elements may be present. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements. Other terms used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly in between," "adjacent" versus "directly adjacent," etc.).

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the embodiments. As used herein, the singular forms "a," "a," "an," and "the" are also meant to include the plural forms unless the context clearly indicates otherwise. Further, it should be understood that the terms "including," "including," "and / or having," as used herein, indicate the presence of said features, integers, steps, operations, elements, and / or components, but that Presence or addition of one or more features, integers, steps, operations, elements, components, and / or groups thereof.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly assigned to one of ordinary skill in the art to which the embodiments pertain. It is further to be understood that terms, such as those defined in commonly used dictionaries, are to be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not in an idealized or overly formal sense are to be interpreted unless expressly defined herein.

1 illustrates a characteristic of an electric machine according to an embodiment of the present invention, wherein an abscissa 101 indicates a normalized speed of the electric machine and an ordinate 103 indicates a power or torque of the electric machine. In particular, shows a curve 105 the dependence of the power on the speed and a curve 107 illustrates a dependence of a torque generated by the electric machine on the rotational speed. In a basic speed range 109 (from 0-1 on abscesses 101 ) the performance increases 105 linear with the speed. In an increased speed range 111 , which is also referred to as a field weakening range, the power remains constant, the torque (curve 107 ) drops sharply with increasing speed. In this increased speed range 111 Therefore, according to an exemplary embodiment of the present invention, a mechanical field weakening can be carried out by mechanically reducing an active length of the electric machine, wherein the excitation field can not be weakened directly proportionally. In particular, a mechanical field weakenability of a conventional electric machine may be limited by the installation space limitations and the stray fields. For field weakening, it may be necessary to further adjust the rotor parts, which may contradict space constraints.

2 shows in a sectional view (seen in the axial direction) an electric machine 200 according to an embodiment of the present invention, which is formed in the present case as an internal rotor electric machine. A rotor 201 is about a rotation axis 203 (Z-axis or axial direction) around a stator 205 rotatable. A radial direction is indicated by reference numerals 207 designated. A circumferential direction is indicated by reference numerals 209 designated. The stator 205 includes a stator support 211 , Stator teeth 213 and stator windings or stator windings 215 , The rotor 201 includes a rotor carrier or rotor yoke 217 and at least one permanent magnet 219 , Other embodiments provide an external rotor electric machine.

3A . 3B show in side sectional view an electric machine according to a non-inventive embodiment, wherein 3A the electric machine during operation in the basic speed range 109 (please refer 1 ) illustrated while 3B the electric machine during operation in the increased speed range 111 illustrated. In the 3 The illustrated electric machine may have a rotor overhang and / or a stator overhang and / or a winding head encapsulation and / or a rotor yoke structure and / or end winding or conical jacket winding. The corresponding components in 2 and 3 are denoted by the same reference numerals, which differ only in the first digit. Thus, the stator includes 305 a stator carrier 311 , Stator teeth 313 and stator windings 315 , Furthermore, there is an axial direction 303 in the drawing plane, so that axial ends of the electric machine 300 are recognizable. In particular, the stator tooth ends 313 at a first axial position 321 , Axially out of axial position 321 or axially outside of the stator tooth 313 is a winding head 323 arranged, which at least partially by an electrical conductor of the windings 315 is formed.

In particular, the electric machine 300 formed by two parts, which are mirror images of a mirror plane, which here by the radial direction 307 goes and perpendicular to the axial direction 303 stands and by reference numerals 325 is designated. In particular, the stator comprises 305 a first part 311 of the stator carrier, a second part 311b of the stator carrier, a first part of the stator teeth 313a and a second part of the stator teeth 313b , The rotor is similar 301 a first rotor carrier 317a and a second rotor carrier 317b on, as well as a first part of a permanent magnet 319a and a second part of the permanent magnet 319b which is mirror-symmetric with respect to the mirror axis 325 are arranged.

The permanent magnet 319a can be axially outward beyond the first axial position 321 lie and / or the stator 311 can be axially outward beyond the first axial position 321 protrude. The first part of the rotor 301 is by reference numerals 301 a and the second part of the rotor 301 is by reference numerals 301b designated. The first part of the stator is by reference numeral 305a and the second part of the stator 305 is by reference numeral 305b designated.

The first part 305a the stator can be a center of gravity position 312a be assigned and the second part 305b the stator can be a center of gravity position 312b be assigned. Furthermore, the first part 301 of the rotor a center of gravity position 302a and the second part 301b the rotor can be a center of gravity position 302b be assigned. An axial distance (ie along the axial direction 303 measured) between the first part 305a of the stator and the first part 302a For example, the rotor may be considered as an axial distance between the center of gravity position 312a the first part of the stator and the center of gravity position 302a be defined of the first part of the rotor. Other definitions, such as an axial offset between the respective axial ends of rotor (carrier) and stator (carrier), are of course also conceivable. In particular, in the 3A taken a first axial distance or offset between the rotor and stator, which is here 0, since the center of gravity position 312a of the first part of the stator has the same axial position as the center of gravity position 302a of the rotor has. Thus, an operation is in the normal speed range 109 (please refer 1 ), wherein an active length l_z_aktiv is achieved, which achieves a maximum overlap between rotor and stator.

3B shows the electric machine 300 in an operating condition which is in the increased speed range 111 (please refer 1 ), wherein in particular a second axial distance or offset d2 between the first part 305a of the stator and the first part 301 of the rotor is taken. To the second axial distance or offset d2 between the stator and the rotor was the first part 301 of the rotor in the axial direction away from the mirror plane 325 moved and the second part 301b of the rotor was in the opposite direction from the mirror plane 325 moved away. As a result, an overlap or an active length of the electric machine is achieved, which is given by l_z_aktiv1 + l_z_aktiv2, which is smaller than the active length l_z_aktiv, which in the normal speed range (see 3A) is taken.

In or on taking the second axial distance d2 (please refer 3B) the permanent magnet protrudes by a second length I r2 over the first axial position 321 axially outward of the stator tooth 313a out. Also, the stator can 311 or. 311b axially to outside the first axial position 321 protrude according to the present invention.

4A . 4B . 4C illustrate occurring stray fields, which are considered according to embodiments of an electric machine. In particular, illustrated 4A in the 3 illustrated electric machine in the base speed range, 4B shows the electric machine in the increased speed range (field weakening area) and 4C additionally illustrates the stray fields due to the magnetic overhang.

For clarity purposes, only the left part of the electric machine, which in 3 is illustrated in the 4A to C (and also in some of the following figures) illustrated. The right part results in each case by reflection at the mirror plane 425 (or the mirror plane of the corresponding figure). In particular, similar or similar elements are in the 2 . 3 and 4 denoted by reference numerals, which do not differ only in the first place. field lines 427 indicate a magnetic field or a magnetic flux. As from the in the 4A to 4C illustrated field lines 427 can be seen, the magnetization or the magnetic flux density in a region which from the first axial position 421 axially within the stator tooth 413 is located, essentially radial components, but hardly any axial components.

In particular, the magnetic field lines in a first axial region ab1 which is from the first axial position 421 within the stator tooth 413 is sufficient, essentially a radial component. Furthermore, the magnetic field lines in a second axial region, which from the first axial position 421 outside the stator tooth 413 sufficient, even axially directed components, which can lead to interference fields.

The effects of these parasitic or unwanted magnetic fields can be investigated metrologically, as in 5 is illustrated. This refers to an abscess 501 an active length of the examined electric machine and an ordinate 503 indicates maximum flux linkage. Curve 505 indicates an ideal course if interference fields are not taken into account, whereby the ideal course can be calculated for example by a simulation. Curve 507 In contrast, shows a real situation in which the interference or stray fields were taken into account, the curve 507 can be generated for example by measurements and / or simulation. In particular, the induced voltages measured at idling of an electromassive prototype at different axial rotor positions with the ideal values (curve 505 ) compared. In this case, the electric machine has a rotor with Oberflächenpermanentmagneten, with differences between different types of rotor are expected. As from the graph of 5 As can be seen, more than 20% of the induced voltage or flux linkage is generated due to stray fields.

1. 1. Statorüberhang,
2. 2. Rotorüberhang.
3. 3. Wickelkopfverguss (relative magnetische Permeabilität größer 1, bzw. größer Luft).
4. 4. Stator- und Rotorüberhang.
5. 5. Statorüberhang mit Wickelkopfverguss (relative magnetische Permeabilität größer 1)
6. 6. Rotorüberhand mit Wickelkopfverguss (relative magnetische Permeabilität größer 1)
7. 7. Stator- und Rotorüberhang mit Wickelkopfverguss (relative magnetische Permeabilität >1).

According to an embodiment of the present invention, a new design for a permanently magnetically excited electric machine with mechanical field weakening is proposed, wherein an effective field weakening is made possible. It can be assumed that the stray fields amplify the electromagnetic field in the field weakening range and that Therefore, the active length of the electric machine must be further reduced by the mechanical movement of the rotor parts. According to an embodiment of the present invention, the stray fields are taken into account in the design of an electric machine and are also used in the formation of torque in order to be able to design a field weakening method more effectively. The following structural changes are possible:

1. 1. stator overhang,
2. 2nd rotor overhang.
3. 3. winding head casting (relative magnetic permeability greater than 1, or greater air).
4. 4. Stator and rotor overhang.
5. 5. Stator overhang with winding head encapsulation (relative magnetic permeability greater than 1)
6. 6. Rotor overhang with winding head casting (relative magnetic permeability greater than 1)
7. 7. Stator and rotor overhang with winding head casting (relative magnetic permeability> 1).

6A . 6B illustrate an exemplary electric machine 600 in the normal speed range ( 6A) and in the increased speed range ( 6B ) According to an embodiment of the present invention, wherein by a combination of stator overhang and rotor overhang the winding heads can be involved in the formation of torque and the torque components of the winding heads can also be reinforced by the winding head casting. In other words, the stray fields can be amplified and participate in the formation of torque. Because of these stray fields, the stator plate or the stator can be saturated, with regard to the formation of a magnetic field. If the rotor parts (of which only one left part in 6A and 6B is illustrated) are moved or moved axially, the stray fields can increase only limited. In this case, an optimal design or determination of the overhangs (stator overhang and / or rotor overhang) can be very crucial for improving the field weakenability, wherein the overhang lengths can be determined by simulations. Further features can be added and the construction methods can be extended.

The stator tooth 613 ends (axially) at the first axial position 621 , The stator carrier 611 protrudes axially beyond the first axial position 621 axially outward of the stator tooth 613 by a third length Is beyond. While in the normal speed range, as in 6A is shown, the first axial distance between the rotor center of gravity position 302 and stator center of gravity position 312 (or between rotor and stator) is assumed, which is 0 here, the permanent magnet extends axially beyond the first axial position 621 by a first length Ir1 out. Here is the first length Ir1 smaller than the third length Is. Like out 6B it can be seen, the permanent magnet protrudes 619 when taking the second axial distance d2 between the center of gravity position 302 of the rotor and the center of gravity position 312 of the stator by a second length I r2 over the first axial position 621 axially to axially outside the stator tooth 613 out. Here is the second length I r2 greater than the third length Is, with the stator overhang or the stator via the first axial position 621 axially to the outside of the stator tooth 613 protrudes.

In the electric machine 600 , what a 6A and 6B is illustrated, a combination of stator overhang, rotor overhang and winding head is provided. In particular, the winding head 623 with an embedding material 624 surrounded, which has a relative magnetic permeability of greater than 1 or in particular between 1.1 and 50 surrounded. In other embodiments, either only one rotor overhang (without stator overhang and without winding head encapsulation) or only one stator overhang (without rotor overhang and without winding head encapsulation) or only one winding head encapsulation (without a stator overhang or without a rotor overhang) can be provided.

1. 1. Die Eisenverluste im Stator wegen axialer Felder,
2. 2. die Verluste in den Wickelköpfen wegen des Wechselfeldes (PM),
3. 3. die Verluste in den leitfähigen Konstruktionsteilen.

Embodiments of the present invention may further reduce additive losses that may occur in mechanical field weakening. In conventional electric machines, in the mechanical field weakening region, the magnetic fields at the outer edges of the rotor can not be established by a soft magnetic material. Relative movement between the rotor and other machine parts may contribute to additional loss in conductive materials. These additional losses were identified by the inventors as follows:

1. 1. The iron losses in the stator due to axial fields,
2. 2. the losses in the windings due to the alternating field (PM),
3. 3. the losses in the conductive construction parts.

The loss mechanisms identified by the inventors are exemplary in FIG 7 illustrated, whereby also an electric machine is schematically illustrated in side sectional view. In the 7 illustrated electric machine 700 is in a housing 731 arranged, wherein by the permanent magnet 719 generated fields 727 with the housing 731 interact and lead to losses. Further, in the stator carrier 711 Iron losses occur and in the windings 723 losses due to the alternating field can occur. According to an embodiment of the present invention, the winding heads of the electric machine can be so be configured that losses on the winding heads, especially in the field weakening area, reduced or even minimized. Furthermore, a modified stator design and a novel rotor design can be used for all rotor types to reduce additional losses. Thus, a reduction in the losses on the conductive structural parts can be mainly made possible, with a smaller reduction of the other additional losses is also expected. Further, housing losses can also be prevented by constructing the housing of low permeability powder material having a required strength. The housing material may also be conductive to provide electromagnetic field shielding. The optimal electromagnetic properties can be optimized by simulation.

8th shows a schematic side sectional view of an electric machine 800 , which in particular has a novel winding head concept. This design is based on a finding of the inventors that, if rotor parts are axially distorted or displaced, permanent magnet losses can be caused in the winding heads. The fields on the winding heads in the field weakening area can differ for different rotor designs. In particular, electric machines with surface permanent magnets can have higher stray fields on the end windings compared to buried permanent magnet electric machines. The winding head losses can be reduced because of external permanent magnetic fields in both electromagnetic machines in that the winding heads are arranged as far away from the rotor. As in 8th is illustrated, is the winding head 823 radially (along the direction 807 ) relatively far from the rotor 801 arranged. In this way, the stator reflux or stator can 811 longer than the stator teeth 813 be built and the winding head 823 can be wound or bent or arranged perpendicular to a stator edge. Due to a partly missing stator yoke, a machine constant can change and the torque can be reduced with the same current injection, which, however, can be considered and considered in a design process.

9A . 9B . 9C illustrate diagrammatically a winding head region or different variants of a development of a winding head ( 9A . 9B . 9C ) according to an embodiment of the present invention. In particular, an electrical conductor 926 which the winding head 923 at least partially forms, be bent in a certain way, in particular perpendicular to a stator edge 910 be bent. In a first axial area ab1 extends the electrical conductor 926 in the axial direction 903 along the stator tooth 913 and in a second axial area starting at 2 , which axially outside the stator tooth 913 lies, forms the electrical conductor 926 at least partially a winding head 923 , In the 9A to 9C illustrated winding heads 923 may be surrounded by an embedding material or may be free of an embedding material.

In the 9A to 9C illustrated winding heads 923 have an axially inner end 928 on, which with the first axial position 921 matches. Furthermore, the winding heads 923 an axially outer end 930 which may, for example, coincide with an axial end position of a rotor. In the first axial area ab1 is the electrical conductor 926 completely in a first radial area r b1 arranged and the electrical conductor 926 is in the second axial region starting at 2 in a second radial area r b2 arranged, which comprises at least a partial radial area trb, which is not with the first radial area r b1 overlaps. In this case, the partial radial region trb is further radially from a rotor (which in the 9A to 9C above the windings 923 disposed) as the first radial region r b1 ,

An extension of the partial radial area trb relative to an extension of the first radial area r b1 may vary, wherein a ratio trb / rb1 may be between 0.2 and 5, in particular between 1 and 5, and in particular between 3 and 5. The higher this ratio, the further at least a part of the winding head 926 be arranged away from the rotor. According to an embodiment of the present invention, a bending geometry of the electrical conductor 926 determined or optimized so as to be able to arrange the partial radial region as far away from the rotor as possible.

As in 9B can be seen, includes the electrical conductor 926 a section 932 , which has both a radially oriented component, and an axially oriented component, wherein the electrical conductor 926 away from that in 9B above arranged rotor is bent. As in 9C is illustrated, the electrical conductor 926 in the second axial area starting at 2 a portion whose longitudinal direction is radially oriented and the conductor has a bend 934 which changes a course direction about 90 degrees away from the rotor. In the 9C illustrated winding configuration may also be referred to as a front winding and the in 9B illustrated winding configuration may also be referred to as a cone-shell winding.

10 Illustrates a schematic side sectional view of an electric machine 1000 , wherein a winding head 1023 according to the in 9C illustrated Construction is used. In the 10 Illustrated elements are designated by the same reference numerals as those in FIG 2 . 3 . 4 . 5 . 6 . 7 . 8th and 9 illustrated elements, however, differ by the preceding one to two digits. Thus, an electric machine can be provided with front winding. 10 may illustrate an operating condition in normal speed range or an operating condition in increased speed range. In combination with the specific winding configuration used in 10 is shown, a stator overhang and / or a rotor overhang and / or a winding head casting may be provided.

The stray fields at the outer edges of the rotor can be reduced or even minimized by design measures. New stator and rotor designs can be defined. For example, if the stator yoke is built longer, the stray fields outside the stator may be partially established.

Such a construction is shown schematically in FIG 11A (Basic speed range) and 11B (Field weakening area) illustrated in side schematic sectional view. In particular, the total loss can be reduced by a stator overhang or by a combination of stator overhang and / or rotor overhang and / or winding head encapsulation. However, additional fields in the stator can be associated with losses. Therefore, a change in the rotor design can bring about a reduction in the additional losses. According to an embodiment of the present invention, a reduction or minimization of the stray fields at the permanent magnetic edges in the field weakening region is achieved by a novel rotor construction, wherein in the base rotational speed range the magnetic fields are established by the stator and the rotor.

12A . 12B . 12C and 12D illustrate in schematic side sectional view electric machines according to embodiment of the present invention with rotor yoke structures, which are designed in particular for the reduction of stray fields. These are each a surface permanent magnet electric machines, with extensions of this design are possible. In particular, the same rotor designs are also applicable or valid for other rotor types. The rotor overflow overhangs can be built from a different material than the rotor yoke. In the 12A to 12D illustrated electric machines can realize a permanent magnet short circuit, whereby the rotor yoke overhangs can be optimized for each design.

In the 12A to 12D Illustrated electric machines each have a rotor yoke structure 1239 on which axially outside the respective permanent magnet 1219 is arranged. The permanent magnet 1219 protrudes in the case of the second axial distance d2 axially beyond the first axial position 1221 to an overhang length or to a second length I r2 axially outward of the stator tooth 1213 out. The rotor yoke structure is here in 12A to 12D , in particular partially by the rotor carrier 1217 formed, wherein this carrier in the region of the rotor yoke structure 1239 in the embodiments which are in to illustrated, at least partially has a rectangular cross-sectional shape. A radial extent ra of the rotor yoke structure can be optimized by simulations.

In the in 12B illustrated embodiment has the conclusion structure 1239 a same radial level as a surface of the permanent magnet 1219 whereas the radial level of the rotor yoke structure 1239 in the case of the picture or 12A below the radial level or the surface of the permanent magnet 1219 lies. 12C illustrates the case in which between the permanent magnet 1219 and at least a part of the rotor yoke structure 1239 a gap 1241 is provided, the axial extent aa can be optimized variably according to simulations. The axial expansions aa and the radial expansions ra, which in 12A to 12D can be changed or optimized according to requirements or simulations.

12D illustrates an embodiment in which the rotor yoke structure 1239 with increasing axial distance from the permanent magnets 1219 rejuvenated in a primary way. A slope of the taper can be optimized by simulation.

According to embodiments of the present invention, a permanent short circuit can be realized, at least partially, also with a disk rotating with the rotor, as exemplified in FIG 13 is illustrated. This can be a conductive disk 1343 as close as possible to an electric machine housing 1331 be built. The disc 1343 can have different designs and be made of different materials or different materials. The motors of external rotor motors can be attached to the bearing with a single-sided rotor bell. An exemplary representation is in 14 illustrated, in which case the rotor bell 1345 which the disc 1443 includes, can be used as a permanent magnet short-circuit disc and rotor yoke.

15A to 15C illustrate possible constructions of a rotor yoke structure which is a disk 1543 includes. Illustrated a possible rotor bell construction for an external rotor machine with mutual mechanical field weakening, 15B illustrates a possible construction of a rotor bell for an external rotor machine with one-sided mechanical field weakening and 15C illustrates a possible rotor bell construction for an external rotor machine with one-sided mechanical field weakening and rotor back-over overhang. It is in 15C the Rotorrückschlussüberhang by reference numerals 1547 denotes which Rotorrückschlussüberhang axially outward of the permanent magnet 1519 protrudes or survives. Permanent magnet short-circuit designs can be used to minimize and, if necessary, cancel out housing losses. As a result, the distance between the machine parts and the housing can be made shorter (without the thickness of the rotor return overhang or the short-circuit disk). Therefore, a permanent magnet short circuit can not only reduce the losses, but also allow for a more compact overall drive. In certain applications, the permanent magnet shorting disc may also be used or used as an eddy current brake.

16A to 16H illustrate possible embodiments of an electric machine provided by the present application. It is shown in each case the operating state of the electric machine in a normal speed range, thus, between the rotor and the stator, a first axial distance is taken. Alone 16 However, embodiments shown allow adjustment of a second axial distance between the rotor and stator, which in particular in the increased speed range (field weakening range) can be taken. In the 16B . 16E . 16F and 16H illustrated embodiments have a stator overhang. In the 16C . 16E . 16G and 16H illustrated embodiments have a rotor overhang. In the 16D . 16F and 16G illustrated embodiments have end windings embedded in a high relative magnetic permeability (greater than one) embedding material. an electric machine is provided, which the in 16C . 16E . 16G or 16H having shown features.

17A . 17B show a further embodiment of an electric machine 1700 in the base speed range ( 17A) and in the field weakening area ( 17B ), which can make mechanical field weakening more effective. In the 17A, B illustrated electric machine 1700 has both a stator overhang, as well as a rotor overhang, as well as a winding head encapsulation, as well as a permanent magnetic short circuit (Rotorrückschlussstrukturen) on. The stator has a stator overhang of a third length is on, the permanent magnet has a rotor overhang of a first length Ir1 , at the first axial distance between stator and rotor or an overhang length or second length I r2 during the second axial distance d2 between rotor and stator. In this case, the second axial distance by reference numeral d2 as the axial distance between the center of gravity coordinates 1702 of the rotor and 1712 be defined by the stator. Furthermore, the winding has 1723 a lap casting 1724 Made of highly permeable material. Furthermore, the electric machine 1700 a rotor yoke structure 1739 on which axially outside the permanent magnet 1719 is arranged.

18A (Grunddrehzahlbereich) and 18B (field weakening area) illustrate schematically in side sectional view of an electric machine 1800 , The electric machine 1800 has a rotor yoke structure 1839 on and a winding head 1823 , which is designed as an end winding or an end winding head, so that the winding 1823 as far as possible from the permanent magnet 1819 (viewed in the radial direction) is arranged.

The features disclosed in the foregoing description, the appended claims and the appended figures may be taken to be and effect both individually and in any combination for the realization of an embodiment in its various forms.

Claims (13)

Apparatus for an electric machine, comprising: a stator having a stator support (611, 1711) and at least one stator tooth (613, 1713) extending in an axial direction (203-1803) and at an axial end of the stator tooth (613, 1713) terminates at a first axial position (621, 1721); and a rotor having at least one permanent magnet (619, 1719), the rotor relative to the stator about an axis of rotation in the axial direction (203-1803) at a first axial distance between the stator and the rotor and at a second axial distance (d2) is rotatable between the stator and the rotor, wherein the rotor and / or the stator in each case by a first part (305 a, 301 a) and a second part (305 b, 301 b) is formed, which are arranged mirror-symmetrically, wherein a mirror plane (325-1825) is oriented perpendicular to the axis of rotation and from the first axial position (621, 1721), wherein the first part (305a, 301a) and the second part (305b, 301b) each have a first axial distance between rotor and stator and a second axial distance (d2) between the rotor and the stator are associated, each starting from the first axial distance of the first part of the rotor and the second part of the rotor in opposite axial directions from the mirror plane 325-1825) are moved away to reach the respective second axial distance (d2) wherein the stator features (611, 1711) extend axially beyond the first axial position (621, 1721) axially outward of the stator tooth (613, 1713) and the permanent magnet (619, 1719) projects at each axial distance between the stator and the rotor, wherein the rotor is rotatable relative to the stator, axially beyond the first axial position (621, 1721) axially outward of the stator tooth (613, 1713). Device according to Claim 1 , further comprising: an electrical conductor (926, 1026) extending in the circumferential direction adjacent to the stator tooth (613, 1713) in a first axial region (ab1) in the axial direction along the stator tooth (613, 1713); a second axial region (ab2), which lies axially outside the stator tooth (613, 1713), at least partially forms a winding head (623, 1723). Device according to Claim 2 in which the conductor (926, 1026) in the winding head (623, 1723) is at least partially surrounded, in particular embedded, by an embedding material (624, 1724) which has a relative magnetic permeability of greater than one, in particular between 1 + 0, 4 × 10 ^-6 and 50, wherein the embedding material (624, 1724) in particular adjacent to the axial end of the stator tooth (613, 1713) and / or in particular axially outside of the stator tooth (613, 1713) to the stator (611, 1711 ) adjoins. Device according to one of the Claims 2 or 3 wherein the winding head (623, 1723) has an axially inner end (928) which coincides with the first axial position and an axially outer end (930) which coincides with an axial position, to which the permanent magnet (619, 1719) protrudes in the case of the first axial distance and / or to which the stator (611, 1711) extends axially beyond the first axial position to axially outside of the stator tooth (613, 1713). Device according to one of the preceding Claims 2 to 4 wherein the electrical conductor (926, 1026) in the first axial region (ab1), which extends from the first axial position within the stator tooth (613, 1713), is disposed completely in a first radial region (rb1), the electrical conductor (926, 1026) in the second axial region (ab2), which extends from the first axial position to the outside of the stator tooth, is arranged in a second radial region (rb2), which comprises at least a partial radial region (tbr), which does not coincide with the first radial region overlaps, wherein the partial radial region (tbr) is arranged radially further away from the rotor than the first radial region (rb1). Device according to Claim 5 wherein the electrical conductor (926, 1026) in the second axial region (ab2) has a bend (934), in particular around between 70 ° and 90 °, away from the rotor. Device according to Claim 5 or 6 wherein the electrical conductor (926, 1026) in the second axial region (ab2) has at least one portion (932) whose longitudinal direction is radially oriented, and / or a portion (932) which is both a radially oriented component and an axial one oriented component. Device according to one of the preceding claims, wherein in the case of the second axial distance (d2) a lower axial overlap between the rotor and stator is achieved than in the case of the first axial distance, wherein the first axial distance in a first speed range (109) and the second axial distance (d2) in a second speed range (111), which is higher than the first speed range (109), are adjustable in order to achieve field weakening in the second speed range (111), so that an operating-induced voltage is less than a supply voltage of a Stator winding is at least partially formed by the electrical conductor (926, 1026). Device according to one of the preceding claims, wherein the permanent magnet (619, 1719) in the case of the first axial distance by a first length (Ir1) and in the case of the second axial distance (d2) by a second length (Ir2), which is greater than that first length (lr1) is axially beyond the first axial position to outside of the stator tooth (613, 1713) protrudes, wherein the stator (611, 1711) by a third length (Is) axially beyond the first axial position (621, 1721) axially outwardly of the stator tooth (613, 1713), wherein the first length (Ir1) is smaller than the third length (Is), the second length (Ir2) being greater than the third length (Is), the second length ( Ir2) in particular an axial extent of the winding head (623, 1723) is equal. An apparatus according to any one of the preceding claims, wherein the apparatus further comprises a rotor back-up structure (1739) co-rotating with the rotor, located axially outward of the permanent magnet (619, 1719) when the second axial distance (d2) is taken. Device according to Claim 10 wherein the rotor further comprises a support (617, 1717) to which the permanent magnet (619, 1719) is attached, the rotor return structure (1739) being formed at least partially by the support (617, 1717), the support (617 , 1717) axially outside the permanent magnet (619, 1719), in particular at least partially has a rectangular cross-sectional shape. Device according to Claim 11 , wherein the support (1239) tapers in its radial extent with increasing axial distance from the permanent magnet (619, 1719), in particular in a linear manner. Device according to one of the Claims 10 to 12 wherein the rotor yoke structure (1739) comprises a disc (1343-1543) disposed in a plane perpendicular to the axis of rotation and connected to the rotor.

Images