Sheet metal stack with positive locking element for force transmission

Abstract

Laminated core (9) for a permanent magnet electric machine (1), with - a rotation axis (14) and - a V-shaped recess (7) in a section plane perpendicular to the axis of rotation (14) through the sheet metal package, which has two legs, wherein - the V-shaped recess (7) in each of the two legs forms a magnetic pocket area (4), and - each magnetic pocket area (4) is shaped to enclose a permanent magnet (8) of the intended shape and size in a form-fitting manner at least with respect to two independent spatial directions, - the magnetic pocket areas (4) lead into a common reluctance area (5) which is not magnetizable, - in the section plane through the sheet metal stack (9) an extension of the reluctance area (5) in the direction of the axis of rotation (14) increases, characterized in that - a T-shaped section (20) in the section plane made of sheet metal parts of the lamination stack (9) projects into the reluctance region (5) between the magnet pocket regions (4), and - a first form-fitting section (15) is formed in a distal end of the T-shaped section (20), - a second positive locking section (16) in sheet metal parts of the sheet metal stack (9) is formed radially further inwards than the magnetic pocket areas (4) opposite the T-shaped section (20) at the edge of the V-shaped recess (7), and - a non-magnetizable positive locking element (25) holds the first positive locking section (15) and the second positive locking section (16) together by positive locking in a radial direction, and - a partial area of ​​the T-shaped section (20) oriented circumferentially in the section plane is supported at least at one shoulder of the lamination stack (9) radially below the magnetic pocket areas (4) by means of a non-magnetizable component (23).

Description

[0001] The present invention relates to a laminated core for a permanently excited electrical machine having a rotational axis and a V-shaped recess in a sectional plane through the laminated core perpendicular to the rotational axis, said recess having two legs, wherein the V-shaped recess forms a magnet pocket region in each of the two legs, and each magnet pocket region is shaped to form-fit a permanent magnet of a specified shape and size at least with respect to two independent spatial directions. The magnet pocket regions open into a common reluctance region which is not magnetized, and in the sectional plane through the laminated core, the extent of the reluctance region increases in the direction of the rotational axis. Furthermore, the present invention relates to an electrical machine having such a laminated core and to a motor vehicle having such an electrical machine.

[0002] An electrical machine, in particular a so-called rotating electrical machine, is a device which is designed to convert energy between the energy forms of mechanical energy and electrical energy. In generator mode, the electrical machine can convert mechanical energy, in particular kinetic or rotational energy, into electrical energy. In motor mode, the electrical machine can convert electrical energy into mechanical energy, in particular kinetic or rotational energy. Generic electrical machines with a stator and a rotor, as well as corresponding laminated cores therefor, are known from the prior art. The movement in which the mechanical energy is stored is in particular a movement of the rotor of the electrical machine relative to the stator. The stator, also called the stator, is usually arranged in a rotationally fixed manner.Accordingly, the movement, especially the rotational movement, is usually carried out by the rotor, also called the runner.

[0003] During normal operation of the electrical machine, there is usually an electromagnetic connection between the stator and the rotor. This electromagnetic connection is created by a magnetic flux within the electrical machine. This magnetic flux is generated at least partially based on the principle of electromagnetism. For this purpose, at least the stator or at least the rotor has at least one winding formed by an electrical conductor. In the case of a permanent-magnet synchronous machine, the rotor has one or more permanent magnets. The electromagnetic connection is then created at least by a magnetic flux between a stator field through a current flow in the stator winding and flux-conducting elements and / or the one or more permanent magnets of the rotor.

[0004] The stator and / or rotor of a rotating electrical machine typically comprise a laminated core. The laminated core is typically made of a ferromagnetic material, such as a ferrite or a plurality of electrically insulated ferromagnetic laminations. The laminated core is designed to conduct or guide the magnetic flux.

[0005] Such a laminated core of the rotor of a permanent-magnet synchronous machine is particularly designed to conduct the magnetic flux of the one or more permanent magnets. To minimize eddy current losses, the laminated core can be constructed from non-conductively connected laminations. In other words, the laminated core can consist of a plurality of lamination layers that are non-conductively connected to one another. For this purpose, the individual lamination layers can each have a non-conductive coating, for example, an electrically insulating coating.

[0006] To accommodate one or more permanent magnets, the laminated core often has a recess into which the respective permanent magnet is inserted axially. Typically, the recess is the same size as the permanent magnet it contains. This positively encloses the permanent magnet in several independent spatial directions. Such recesses can therefore also be referred to as magnetic pockets.

[0007] From the generic document DE 10 2020 113 938 A1, a laminated core for a permanent-magnet synchronous machine with at least one recess is known, wherein the at least one recess forms a magnet pocket region in some areas and wherein the at least one recess in the magnet pocket region is shaped to form-fit a permanent magnet of intended shape and size at least with respect to two independent spatial directions.In order to enable improved torque output with the same use of installation space and the same amount of permanent magnetic material, it is provided that the at least one recess has a reluctance region in a region different from the magnet pocket region, wherein in an axial sectional plane through the laminated core, an extension of the at least one recess along a spatial direction in the reluctance region is greater than in the magnet pocket region, and wherein the spatial direction runs perpendicular to a main extension direction of the magnet pocket region.

[0008] Furthermore, the publication DE 10 2016 219 120 A1 discloses an electric machine with low stray flux and high speed stability. The rotor has several indentations and magnetizable peripheral bodies. A magnet receptacle is formed between each indentation and the corresponding peripheral body. Each peripheral body is held on the rotor in an armature section that extends into an anchoring channel.

[0009] The publication US 2013 / 0 119 807 A1 shows a rotor of an electric machine. A pair of permanent magnets is arranged in a V-shape in the rotor core. The pair of permanent magnets is separated in an inner circumferential direction of the rotor core. The rotor core includes a gap. The pair of permanent magnets is arranged for each gap so that the pole faces face the inner wall surfaces of the gap over the entire length.

[0010] The published patent application DE 10 2017 205 858 A1 discloses a rotor for a permanently excited synchronous machine. The rotor comprises a rotor body in which at least one recess is formed, which extends substantially in an axial direction at least partially through the rotor body. The recess includes at least two elongated first regions and at least one second region extending in a radial direction and extending radially between the two first regions. A permanent magnet is accommodated in each of the first regions, and a connecting element is accommodated in the second region. The connecting element has a geometric widening at its respective ends corresponding to the contour of the second region of the recess.

[0011] The object of the present invention is to propose a laminated core that enables an increased reluctance torque with the lowest possible leakage flow and high mechanical strength.

[0012] According to the invention, this object is achieved by laminated cores according to the independent claims. Advantageous developments of the invention emerge from the subclaims. Furthermore, an electric machine and a corresponding motor vehicle are also provided.

[0013] According to a first aspect, a laminated core is provided for a permanent-magnet electrical machine with a rotational axis. In particular, the laminated core can be used for a synchronous reluctance motor. However, the laminated core can generally also be used for all of the electrical machines mentioned above.

[0014] The laminated core according to the first aspect is not claimed, but serves to better understand the laminated core according to the second aspect of this invention.

[0015] The laminated core has an axis of rotation, which is used as a reference value below. Thus, the laminated core has a V-shaped recess in a section plane perpendicular to the axis of rotation, which has two legs. The recess is therefore essentially in the shape of a "V." The V-shaped recess forms a magnetic pocket area in each of the two legs. A magnetic pocket area is therefore an area in the section plane that is assigned to a magnetic pocket. In the section plane, a magnetic pocket area usually has an elongated, rectangular shape (possibly open at the end faces) and forms one leg of the V-shaped recess.

[0016] Each magnetic pocket area is designed to form-fit a permanent magnet of the specified shape and size in at least two independent spatial directions. The permanent magnets are therefore predefined components with a predetermined shape that determines the internal configuration of the respective magnetic pocket area. The two independent spatial directions correspond to two orthogonal spatial directions. Since the magnetic pocket area positively surrounds a respective permanent magnet in at least two independent spatial directions, the permanent magnet, held by the magnetic pocket area, cannot be moved in these two spatial directions.

[0017] The magnetic pocket areas of the V-shaped recess open into a common reluctance area, which is not magnetizable. This reluctance area is therefore located at the tip of the V-shape of the recess. The magnetic pocket areas are open towards the reluctance area. For example, a shoulder can prevent a permanent magnet in the magnetic pocket area from slipping into the reluctance area. The reluctance area between the two magnetic pocket areas is generally not magnetizable. This means that the components located in the reluctance area are also not magnetizable. For example, the reluctance area is not magnetizable if it is cast with a non-magnetizable material. However, a projection of the laminated core (hereinafter, for example, a T-shaped section) can protrude into the reluctance area.

[0018] In the cross-sectional plane through the laminated core, the reluctance region expands in the direction of the rotation axis. This means that the reluctance region becomes wider in the tangential direction or circumferential direction with increasing proximity to the shaft or rotation axis. For example, if the magnetic pocket areas delimit the reluctance region in the radially outer region, the width of the reluctance region radially further inward is greater than the distance between the magnetic pocket areas.

[0019] A first form-fitting section is formed in the laminations of the laminated core at the edge of the V-shaped recess between the magnetic pocket regions. This means that the first form-fitting section lies in the radially outer region of the reluctance region. The first form-fitting section is therefore located in an intermediate region in the circumferential direction between the magnetic pocket regions. The radial position of the first form-fitting section can be selected as required. Preferably, the first form-fitting section lies radially at the same position as or outside the radial position at which the magnetic pocket regions or the corresponding inserted permanent magnets are closest together. This makes it possible to avoid high stray or leakage fluxes at the point where the permanent magnets are closest to one another, because a non-magnetizable form-fitting body engages in the first form-fitting section.

[0020] A second form-locking section is formed in the laminations of the laminated core at the edge of the V-shaped recesses, radially further inward than the magnetic pocket areas. The second form-locking section is thus located radially further inward in the laminated core than the magnetic pocket areas and the first form-locking section. Since the reluctance region increases in the direction of the rotation axis, the radially inner region of the reluctance region, due to its trapezoidal shape, forms a form-locking section for positive holding in the radially outward direction.

[0021] A non-magnetizable form-locking body holds the first form-locking section and the second form-locking section together in a radial direction by means of a form-locking connection. This means that forces can be transmitted in a radial direction between the form-locking sections of the reluctance region by means of the form-locking body. For example, it is possible for a laminated core section located radially outside the V-shaped recess to be held radially inward by the form-locking body when the laminated core rotates. This allows the centrifugal forces of this laminated core section between the legs of the V-shaped recess to be absorbed by a laminated core section radially inside the second form-locking section. The second form-locking section can alternatively or additionally be formed by a special shaping of the inner surface of the reluctance region.

[0022] In a second aspect of the present invention, a laminated core is provided which also has the above-mentioned axis of rotation and the V-shaped recess in a sectional plane through the laminated core perpendicular to the axis of rotation, which recess has two legs. Likewise, the V-shaped recess forms a magnet pocket region in each of the two legs, and each magnet pocket region is shaped to positively enclose a permanent magnet of a specified shape and size at least with respect to two independent spatial directions. The magnet pocket regions open into a common reluctance region which is not magnetizable, and in the sectional plane through the laminated core, the extent of the reluctance region increases in the direction of the axis of rotation.In contrast to the laminated core according to the first aspect, here a section made of sheet metal parts of the laminated core, which is T-shaped in the sectional plane, protrudes into the reluctance region between the magnetic pocket regions. This means that the reluctance region has approximately the shape of an upside-down mushroom, with the T-shaped section made of sheet metal parts of the laminated core protruding through the shaft of the mushroom from radially outside to radially inside into a head region of the mushroom-shaped reluctance region. Two shoulders of the laminated core, which are opposite one another in the circumferential direction, determine the narrowest point of the shaft of the mushroom-shaped reluctance region. The section, which is T-shaped in the sectional plane, has a radially running part that protrudes between these shoulders or the shaft region of the mushroom-shaped reluctance region.The crossbeam of the T-shaped section made of sheet metal parts in the sectional plane is located in the head area of ​​the mushroom-shaped reluctance zone and has a larger circumferential extension than the distance between the shoulders. This results in a positive fit of the T-shaped section in the reluctance zone in a radially outward direction.

[0023] A first form-fitting section is formed in a distal end of the T-shaped section, i.e., the crossbar of the T-shaped section, which is directed radially inward. This first form-fitting section can be realized by shaping the radially inward-facing surface of the T-shaped section.

[0024] A second form-locking section is formed in sheet metal parts of the laminated core at the edge of the V-shaped recess, radially further inward than the magnetic pocket areas opposite the T-shaped section. The second form-locking section is therefore also part of the laminated core and is characterized by one or more form-locking elements that can absorb radial outward forces.

[0025] A non-magnetizable form-locking body holds the first form-locking section and the second form-locking section together in a radial direction. This form-locking body can hold the T-shaped section, which penetrates the V-shaped recess in a radial direction, against centrifugal forces.

[0026] The following training courses may refer to the two aspects mentioned above, unless this is explicitly excluded.

[0027] According to a further development of the laminated cores, the first and / or second form-locking section is provided with a meandering shape or mushroom-shaped projections, which are engaged behind by the form-locking body to create the form-locking connection. These mushroom-shaped projections and corresponding negative shapes of the form-locking body allow connections similar to puzzle pieces to be created. Such puzzle connections have the advantage that the projections are formed exclusively by rounded sections, thus avoiding corners that can cause problems when inserting the form-locking body into the reluctance area.

[0028] According to a further embodiment relating to a laminated core according to the first aspect, the form-locking body completely fills the reluctance region. This means that uniform magnetization conditions are present in the reluctance region. The form-locking body essentially represents a negative form of the reluctance region. The form-locking body can be pushed axially into the reluctance region during assembly without leaving any gaps.

[0029] In a further embodiment, the form-locking body can be formed by pouring a non-magnetizable material into the reluctance region. By pouring the reluctance region, the casting material can easily penetrate even the undercuts of the form-locking body. A particular advantage is that the tolerances of the form-locking body and the respective form-locking section can be large, which simplifies production accordingly. The material can be poured out of a non-magnetizable material such as plastic, epoxy resin, and the like. The material must be suitable for absorbing the corresponding forces between the form-locking sections.

[0030] In an alternative embodiment, the form-fitting body is made of ceramic, non-magnetic stainless steel, or fiber-reinforced plastic. Other materials capable of absorbing the corresponding tensile forces may also be considered. The only important thing is that they are non-magnetic materials to keep leakage as low as possible.

[0031] The laminated core according to the second aspect of the invention provides that a partial region (crossbar) of the T-shaped section, which is oriented in the circumferential direction in the sectional plane, is supported by a non-magnetizable component (pressure-absorbing component) at least on one shoulder of the laminated core radially below the magnetic pocket regions. This results in the advantage that the T-shaped section is magnetically cut off from the at least one shoulder. Furthermore, not all centrifugal forces have to be held by the form-locking body. Rather, this embodiment results in a double form-locking connection through the at least one shoulder in the laminated core and the form-locking sections together with the form-locking body.

[0032] In a further development of the invention, the form-locking body in the reluctance region is cast with a different material than the form-locking body. This means that the form-locking body does not completely fill the reluctance region. Rather, one or more gaps exist when the form-locking body is inserted into the reluctance region, and these gaps are filled with a material that is different from the material of the form-locking body. In this case, for example, the casting material may not have to absorb tensile and compressive forces.

[0033] According to one embodiment of the invention, an electrical machine is equipped with a laminated core of the aforementioned type. As a result, a permanent magnet synchronous machine, a synchronous reluctance machine, and the like, for example, can benefit from increased torque or improved tractive force transmission. Such an improved electrical machine also offers advantages in a motor vehicle equipped with it.

[0034] The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle.

[0035] The invention also encompasses combinations of the features of the described embodiments. The invention therefore also encompasses implementations that each comprise a combination of the features of several of the described embodiments, unless the embodiments are described as mutually exclusive.

[0036] Exemplary embodiments of the invention are described below. Shown are: Fig. 1 a sector of a cross-section perpendicular to the axis of rotation of an electrical machine; Fig. 2 shows an enlarged reluctance region of the sector according to another embodiment; Fig. 3 shows an enlarged reluctance region of the sector according to another embodiment; Fig. 4 shows a sector of a cross-section perpendicular to the axis of rotation of an electrical machine according to an alternative embodiment; Fig. 5 shows an enlarged reluctance range of the sector according to another embodiment, Fig. 6 an enlarged reluctance range of the sector according to yet another embodiment; and Fig. 7 shows an enlarged reluctance region of the sector according to yet another embodiment.

[0037] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that can be considered independently of one another, each of which also develops the invention independently of one another. Therefore, the disclosure is intended to encompass combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0038] In the figures, the same reference symbols designate elements with the same function.

[0039] Fig. Figure 1 shows an electrical machine 1 with a stator 2 or stator and a rotor 3 in a highly schematic section axial to the rotational axis 14. The stator 2 and the rotor 3 are spaced or separated from each other by an air gap 13. The stator 2 each has windings 12 for generating an alternating electromagnetic field. In order to generate torque by means of the electrical machine 1, the respective electric or magnetic fields of the stator 2 and the rotor 3 must be operatively connected or linked to each other. In this case, it is a reluctance machine whose torque is generated essentially by reluctance force.

[0040] The torque M of the synchronous reluctance motor can be calculated using the following formula: M=k[1Lq−1Ld]ψ2sin2δ with the motor constant k, the inductances in q- and d-direction L q and L d , the magnetic flux ψ and the rotor angle δ. The better the flux guidance in the d-axis (sector edge in Fig. 1) and the stronger the flow in the q-axis (vertical axis in Fig. 1) is obstructed, the greater the engine torque.

[0041] In the different versions according to the Fig. 1 to 7, the rotor 3 has a laminated core 9. The laminated core 9 serves, among other things, to conduct a respective magnetic flux of the windings 12 and the permanent magnets 8. In addition, the laminated core 9 serves for the respective positioning and holding of the permanent magnets 8. To accommodate the permanent magnets 8, the respective laminated core 9 has, according to the Fig. 1 to 5 recesses 7 and 10. The recesses 10 are formed, for example, in a conventional manner, which is why they are only mentioned here as an option and in passing. The recesses 7, which in this case are V-shaped, are described in more detail below.

[0042] Further referring to all Fig. 1 to 7, the V-shaped recesses 7 each have a magnetic pocket region 4 at the limbs of the V-shape and a reluctance region 5 at the tip of the V-shape, where the two limbs converge. At the distal ends of the limbs, adjacent to the magnetic pocket regions 4, there are angled recess regions that are important for the flux-blocking function but are not explained in detail here. The V-shaped recess 7 is preferably axially symmetrical with respect to the q-axis.

[0043] The permanent magnets 8 are held in a form-fitting manner in the magnetic pocket areas 4. For this purpose, each magnetic pocket area 4 has corresponding shoulders or bent end areas. The form-fitting arrangement exists in two independent spatial directions. These independent, mutually perpendicular spatial directions run parallel to the sides of the rectangle, which defines the section of the permanent magnet 8 in the Fig. 1 to 7, each symbolized by the sectional plane perpendicular to the rotation axis 14. The permanent magnets 8 are inserted axially into the magnet pocket areas 4 for assembly. With respect to the spatial directions perpendicular to the insertion direction, a positive fit is provided by the laminated core.

[0044] The reluctance region 5 at the tip of the V-shaped recess 7 has an approximately trapezoidal shape with the longer side facing the rotation axis 4 (also known as a bell shape due to the curved sides). The shorter side of the trapezoid is located between the permanent magnets 8, and in particular between those edges of the permanent magnets 8 that represent the shortest distance between the permanent magnets.

[0045] The reluctance region 5 has a first form-locking section 15 and a second form-locking section 16. The two form-locking sections are formed by edge sections of the laminated core. They can therefore also be considered as part of the laminations of the laminated core. In relation to the trapezoidal shape mentioned above, the first form-locking section is located radially further outwards on the shorter trapezoidal side and the second form-locking section is located radially further inwards on the longer trapezoidal side. In the present example, the sides of the trapezoid are not straight and have a curved shape, which also serves to form a respective shoulder for the form-locking to hold the respective permanent magnet 8. With the curved sides, the reluctance region 5 resembles the Fig. 1 to 7 also resembles a section through a bell. Accordingly, the second form-fitting section 16 is formed on the wide underside of the bell, and the first form-fitting section 15 is formed on the narrow upper side of the bell.

[0046] In the present example, the edge of the laminated core in the form-fitting sections runs in a meandering shape (mushroom-shaped projections). This meandering shape is so pronounced that undercuts arise from a radial perspective. These undercuts result in form-fitting connections in all spatial directions except the axial directions. If the reluctance region 5 is filled with a body that engages behind the meander-shaped laminated core cuts, a form-fitting connection (puzzle connection) is created, through which forces can be transmitted, particularly in the radial direction. This applies to both the first form-fitting section 15 and the second form-fitting section 16. This allows radial forces to be transmitted via the body in the reluctance region. This allows a central laminated core section 17, which is located directly above the V-shaped recess for flux conduction, to be held against centrifugal forces.

[0047] In the example of Fig. 1, the reluctance region 5 is cast with a non-magnetizable material. For example, the material cast can be made of a plastic, in particular a fiber-reinforced plastic, epoxy resin, or the like. When solidified, the material cast can transmit the forces between the form-fitting sections in the radial direction.

[0048] Preferably, the reluctance region 5 is located on the shortest connection between the two permanent magnets in the magnet pocket areas of the V-shaped recess 7. No radial web made of sheet metal sections of the laminated core 3 runs completely between the permanent magnets 8 in the radial direction. Rather, the reluctance region 5 between the permanent magnets 8 in the V-shaped recess 7 contains exclusively or largely non-magnetizable material. This results in increased magnetic resistance at the narrowest point between the permanent magnets 8 and thus a reduced leakage flux. Since the direct magnetic flux between the magnets is thus cut off, improved flux blocking occurs in this region. This allows a higher reluctance torque to be achieved, while still ensuring strength, particularly against centrifugal forces.

[0049] The form-fitting sections 15 and 16 are in the Fig. 1 to 7 are each realized in a meandering pattern. However, the form fit can generally be achieved through dovetail joints or other shaped undercuts.

[0050] While in Fig. 1 the reluctance area 5 is completely cast, in the embodiment of Fig. 2, which shows only an enlarged section of the sector around the reluctance region 5, between the first form-locking section 15 and the second form-locking section 16 there is a plugged, non-magnetizable form-locking body 18 that only partially fills the reluctance region. This form-locking body 18 therefore represents a partial form-locking body, which in the present case transmits the tensile forces Fz between the first form-locking section 15 and the second form-locking section 16. In the region of the form-locking sections 15, 16, the partial form-locking body has essentially the same extent in the circumferential direction as these. In the central region between the form-locking sections, the partial form-locking body can be tapered.

[0051] The space not filled by the form-locking body 18 or the partial form-locking body in the reluctance region 5 can be filled with a non-magnetizable material 19. This non-magnetizable material 19, for example, absorbs no or only insignificant tensile forces in the radial direction.

[0052] Fig. 3 shows how Fig. 2 merely an enlarged section around the reluctance region 5. In the embodiment of Fig. 3, the entire reluctance region 5 is completely filled by an axially inserted form-locking body 18'. The form-locking body 18' thus forms the spatial negative of the reluctance region 5, so that it is completely filled by the form-locking body 18'. This form-locking body can be made, for example, of ceramic or a non-magnetizable stainless steel and have sufficient tensile strength.

[0053] Due to the trapezoidal bell shape, in which the form-locking body 18' is wider radially inward in the circumferential direction than radially outward, a further form fit is created on its flanks together with the correspondingly negatively shaped laminated core area in relation to the radially outward direction. The form-locking body 18' is thus held against centrifugal forces not only by the form-locking section 16, but also by its flanks 20, which converge towards each other in the radial direction. The same naturally applies to the Fig. 1 form-fitting body obtained by casting in the reluctance range 5.

[0054] In the Fig. 4 to 7, exemplary embodiments of the second aspect of the present invention are schematically illustrated. These embodiments correspond to the configurations according to FIGS. 1 and 2, except for the reluctance region 5. Fig. 1 to 3. Therefore, further description of the same components is omitted.

[0055] Fig. 4 shows how Fig. 1 shows a sector of a sectional plane of a laminated core for a rotating electrical machine, wherein the sectional plane is perpendicular to the rotation axis 14. In all examples of Fig. 4 to 7, a T-shaped section 20, which is preferably formed in one piece with the laminated core, projects between the magnet pocket regions 4 or the permanent magnets 8 into the reluctance region 5. The T-shaped section 20 thus extends with its proximal foot (foot of the "T") from the laminated core section 17, which is located radially outside the V-shaped recess 7, in the radial direction inwards and ends in a laminated core beam (herein also called cross beam 22), which in the sectional view extends with its main direction of extension perpendicular thereto (i.e. in the circumferential direction). This T-shaped section 20 is in Fig. 5 is shown enlarged. Also visible there are the base 21, which runs in the radial direction, and the crossbar 22, which runs perpendicular to it in section. The T-shaped section 20 is therefore preferably formed integrally with the laminated core and is itself made of sheet metal parts of this laminated core. At the narrowest point between the permanent magnets 8, its base 21 protrudes radially into the reluctance region 5 located there.

[0056] The first form-locking section 15 is arranged here directly on the crossbeam 22 of the T-shaped section 20 and is radially opposite the form-locking section 16, which is located at the radially innermost point of the reluctance region 5. While the first form-locking section 15 is located on the radially innermost side of the crossbeam 22, pressure transmission elements 23 are located on the radially outermost side of the crossbeam 22. These pressure transmission elements 23 can transmit pressure in the radial direction to respective shoulders 24 of the laminated core, which are located radially above or radially within the magnet pocket regions 4. The pressure transmission elements 23 are not cast, but are pushed in the axial direction into the laminated core between the crossbeam 23 and the shoulders 24. The remaining space of the reluctance region 5 can be Fig. 5 can be cast with a non-magnetic material such as plastic or epoxy resin. In this case, the casting material transfers the forces between the two form-fitting sections 15 and 16.

[0057] The compressive forces resulting from the further positive engagement between the T-shaped section 20 and the shoulders 24 are transmitted by the pressure transmission elements 23 when the rotor 3 rotates.

[0058] The alternative in Fig. 4 shows a form-locking body 25 located between the first form-locking section 15 of the T-shaped section 20 and the second form-locking section 16. The form-locking body 25 is not cast into the reluctance region 4, but is axially inserted into it and undercuts the mushroom-shaped projections of the respective meandering laminated core edge. The remaining space of the reluctance region 5 can, in turn, be cast. In this case, the form-locking body 25 transmits the radial tensile forces, while the potting material plays a rather subordinate role with regard to force transmission. The pressure transmission elements 23 also transmit any radial compressive forces occurring to corresponding shoulders 24.

[0059] The enlarged section of the reluctance area 5 in Fig. Figure 6 shows an alternative embodiment to that of Fig. 4. Only the pressure transmission elements 23 have been omitted here. The cast material between the crossbeam 22 of the T-shaped section 20 and the shoulders 24 absorbs any compressive forces in the radial direction.

[0060] The same applies to the enlarged reluctance range 5 in Fig. 7, which is an alternative to the embodiment of Fig. 5. Here, too, the pressure transmission elements 23 were omitted. Accordingly, not only the tensile forces between the form-locking sections 15 and 16, but also the compressive forces between the crossbeam 22 and the shoulders 24 are transmitted via the cast material.

[0061] Advantageously, all embodiments reduce or prevent leakage flow through a web that runs continuously between the magnet pocket areas. This allows for higher maximum torque and improved efficiency. Furthermore, a large reluctance area is located between the V-shaped magnets to enable the provision of larger reluctance torques. Furthermore, the above embodiments ensure sufficient mechanical strength, particularly with regard to the power transmission in the radial direction due to centrifugal forces.

[0062] Ultimately, this results in improved power density, meaning more torque per unit weight or more torque per unit of installation space in relation to the magnet weight or magnet volume. This reduces magnet costs and thus the overall costs of the drive system, especially for a motor vehicle.

Claims

[1] Laminated core (9) for a permanent magnet electrical machine (1), with - a rotation axis (14) and - a V-shaped recess (7) in a sectional plane perpendicular to the rotation axis (14) through the laminated core, which recess has two legs, wherein - the V-shaped recess (7) forms a magnetic pocket area (4) in each of the two legs, and - each magnetic pocket area (4) is designed to form-fit a permanent magnet (8) of the intended shape and size at least with respect to two independent spatial directions, - the magnetic pocket areas (4) open into a common reluctance area (5) which is not magnetizable, - in the sectional plane through the laminated core (9) an extension of the reluctance region (5) increases in the direction of the rotation axis (14), characterized by , that - a section (20) which is T-shaped in the sectional plane and consists of sheet metal parts of the laminated core (9) and extends into the reluctance region (5) between the magnetic pocket regions (4), and - a first form-fitting section (15) is formed in a distal end of the T-shaped section (20), - a second form-fitting section (16) is formed in sheet metal parts of the laminated core (9) at the edge of the V-shaped recess (7) radially further inward than the magnet pocket areas (4) opposite the T-shaped section (20), and - a non-magnetizable form-locking body (25) holds the first form-locking section (15) and the second form-locking section (16) together by form-locking in the radial direction, and - a partial region of the T-shaped section (20) aligned in the circumferential direction in the sectional plane is supported at least on one shoulder of the laminated core (9) radially below the magnetic pocket regions (4) by means of a non-magnetizable component (23). [2] Laminated core according to claim 1, wherein the first and / or the second form-fitting section (15, 16) has mushroom-shaped projections in the sectional plane, which are engaged behind by the form-fitting body (18, 18', 25) to produce the form-fitting connection. [3] Laminated core according to one of the preceding claims, wherein the form-fitting body (18, 18', 25) is formed by pouring the reluctance region (5) with a non-magnetizable material. [4] Laminated core according to one of claims 1 to 2, wherein the form-fitting body (18, 18', 25) is formed from a ceramic, from a non-magnetizable stainless steel or from a fiber-reinforced plastic. [5] Laminated core according to one of the preceding claims, wherein the form-fitting body (18, 18', 25) is cast in the reluctance region (5) with a material different from the form-fitting body. [6] Electrical machine (1) with a laminated core (9) according to one of the preceding claims. [7] Motor vehicle with an electric machine (1) according to claim 6.

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