ROTOR SHEET, ROTOR SHEET PACK, ROTOR, ELECTRICAL MACHINE AND VEHICLE

Description

[0001] The present invention relates to a rotor lamination. The invention also relates to a rotor lamination stack, a rotor, an electrical machine, and a vehicle.

[0002] DE 10 2017 209207 A1 discloses a rotor of an electric machine having a pair of magnetic pockets for accommodating permanent magnets, symmetrical with respect to an axis of symmetry extending radially through a center point of the rotor. Each magnetic pocket has an edge region whose distance from a circumferential edge of the rotor is the same width. One leg side has a projection and a recess.

[0003] WO 2018 / 189822 A1 discloses an IPM rotor with a plurality of layered laminations having magnet receiving holes. A lamination with a magnet receiving hole has a projection. Toward the outer contour, an edge of the magnet receiving hole extends in a direction opposite to the projection.

[0004] US 2015 / 162790 A1 discloses a rotor core with a plurality of circumferentially arranged magnet through-holes, each having a magnet insert portion and a pair of non-magnetic portions. The rotor core forms a bridge portion between an outer surface of the rotor core and an inner wall of one of the non-magnetic portions. The inner wall extends concentrically with the outer surface of the rotor core.

[0005] Another rotor lamination is known from DE 10 2013 219 260 A1.

[0006] Furthermore, EP 3 352 337 A2 discloses a rotor laminated core which is divided into a plurality of equally sized and equidistantly arranged sectors, each having a first half-sector and a second half-sector separated from the first half-sector by a separation plane, wherein a through-opening is formed in the first half-sector, which through-opening has a first leg side, the imaginary extension of which intersects the separation plane at an acute angle open radially outwards, a second leg side which runs parallel to the first leg side and the imaginary extension of which intersects the separation plane radially further outwards than the imaginary extension of the first leg side, and an edge connecting ends of the leg sides which are facing away from the separation plane, wherein a further through-opening which is mirror-symmetrical to the through-opening with respect to the separation plane is formed in the second half-sector.This publication discloses a laminated core formed from rotor laminations. The rotor lamination comprises first and second recesses arranged circumferentially around the rotor lamination. The first and second recesses serve to accommodate permanent magnets and, for this purpose, have a slot-like, elongated, and straight shape. The first and second recesses are oriented such that their longitudinal extensions run obliquely with respect to a radial direction. Two first and second recesses arranged in a V-shape relative to each other form a rotor pole.

[0007] When a rotor constructed from such rotor laminations operates at high speeds, significant mechanical stresses occur in the bridge areas between the radially outer ends of the through-holes and the outer contour of the rotor lamination. The mechanical stress resistance of these bridge areas frequently limits the permissible rotor speed. To increase this speed, a larger distance from the outer diameter must be provided for a given through-hole shape, which, however, usually leads to undesirable magnetic stray fluxes, or a more expensive material with higher stress resistance must be used for the rotor laminations.

[0008] The invention is therefore based on the object of specifying an improved design of rotor laminations, in particular for use in a drive machine for a vehicle.

[0009] To achieve this object, the invention provides a rotor lamination according to claim 1. Advantageous embodiments are the subject of the dependent claims.

[0010] The invention is based on the finding that a significant reduction of mechanical stresses in a bridge region between the edge and the outer contour of the rotor lamination can be achieved if the edge has the equidistant section. The rotor lamination according to the invention advantageously makes it possible to operate a rotor formed from rotor laminations according to the invention at a higher speed or, alternatively, to form rotor laminations with a lower stray flux and / or from a material with lower mechanical resistance at a given speed, which reduces the cost of such a rotor lamination.

[0011] In the sense of the present invention, the edge runs equidistant to the outer contour of the rotor lamination if the edge consists of those points that lie at a predetermined distance on a normal of a point of the outer contour.

[0012] Typically, the rotor lamination according to the invention is provided with a circular outer contour. However, irregularly round outer contours are also conceivable, for example. The equidistant section is in particular also concentric to the outer contour. The rotor lamination according to the invention preferably has at least four, particularly preferably at least six, very particularly preferably at least eight sectors. A chord of the equidistant section typically has a length of at least 25 percent, preferably at least 50 percent, particularly preferably at least 75 percent, of a distance between the first limb side and the second limb side. While it is stated that the through-openings are mirror-symmetrical, this does not mean that the rotor lamination as a whole is necessarily mirror-symmetrical in both half-sectors.

[0013] The projection provided according to the invention advantageously forms a lateral limit or stop for a permanent magnet to be accommodated in the through-opening and also facilitates the positioning of the permanent magnets during rotor production. A further projection can be adjacent to the end of the first leg side facing the separation plane.

[0014] In order to enable an enlargement of the equidistant section, the recess is provided according to the invention in the transition of the edge into the equidistant section as seen from the first leg side.

[0015] In certain embodiments, it is provided that the projection lies between the first leg side and the recess.

[0016] It can be provided that the edge between the recess and the equidistant section has a straight section, preferably running parallel to the imaginary extension of the first leg side.

[0017] Lower point-specific mechanical stresses can be achieved by rounding the edge into the equidistant section with a smaller curve radius than that of the equidistant section.

[0018] In the rotor lamination according to the invention, it can further be provided that the edge transitions from the second leg side into the equidistant section via a rounded portion whose curve radius is smaller than that of the equidistant section. This also allows for the prevention or reduction of localized stress increases at the transition from the second leg side to the equidistant section.

[0019] In order to form an improved magnetic air gap field, it is further preferred that a second through-opening is formed in the first half-sector, wherein the second through-opening has a first leg side, the imaginary extension of which intersects the separation plane at an acute angle open radially outwards radially further outwards than the imaginary extension of the second leg side of the first through-opening, and a second leg side which runs parallel to the first leg side and the imaginary extension of which intersects the separation plane radially further outwards than the imaginary extension of the first leg side, wherein a further through-opening is formed in the second half-sector and is mirror-symmetrical to the second through-opening with respect to the separation plane. Such an arrangement is also referred to as a double-V arrangement.

[0020] It is also conceivable for a further through-opening to be formed in the first half-sector, perpendicular to the separation plane. Such an arrangement is also referred to as a triangular or delta arrangement.

[0021] The object underlying the invention is further achieved by a rotor lamination stack according to claim 11.

[0022] The object underlying the invention is also achieved by a rotor according to claim 12.

[0023] In addition, the object underlying the invention is achieved by an electrical machine according to claim 13.

[0024] Finally, the object underlying the invention is achieved by a vehicle according to claim 14.

[0025] Further advantages and details of the present invention will become apparent from the exemplary embodiments described below, as well as from the drawings. These are schematic representations and show: Fig. 1 is a plan view of an embodiment of the rotor lamination according to the invention; Fig. 2 is a plan view of a half sector of the Fig. 1 shown rotor lamination; Fig. 3 a detailed view of an edge of a through-hole of the Fig. 1 shown rotor lamination; Fig. 4 shows a detailed view of an edge of a through-opening of a first comparative example of a rotor lamination; Fig. 5 shows a detailed view of an edge of a through-opening of a second comparative example of a rotor lamination; Fig. 6 shows a schematic diagram of an exemplary embodiment of an electrical machine according to the invention, comprising an exemplary embodiment of a rotor according to the invention with a rotor lamination stack according to the invention; Fig. 7 shows a plan view of a half-sector of a rotor lamination according to the prior art; and Fig. 8 shows a schematic diagram of an exemplary embodiment of the vehicle according to the invention.

[0026] Fig. 1 is a plan view of an exemplary embodiment of a rotor lamination 1 that is divided into a plurality of equally sized, equidistantly arranged sectors 2a to 2h. The number of sectors 2a to 2h is eight in this example.

[0027] Each sector 2a to 2h has a first half-sector 3 and a second half-sector 5 separated from the first half-sector 3 by a separation plane 4. A first through-opening 6 and a second through-opening 7 are formed in the first half-sector 3. In the second half-sector 5, a further through-opening 8 is formed, mirror-symmetrically to the first through-opening 6 with respect to the separation plane 4, and a further through-opening 9 is formed to the second through-opening 7. Due to the symmetry of the through-openings 6 to 9, only the through-openings 6 and 7 provided in the first half-sector 3 in sector 2a are described below; these through-openings are therefore also representative of the half-sectors 3, 5 and the remaining sectors 2b to 2g.

[0028] Fig. 2 is a plan view of the first half-sector 3 of sector 2a.

[0029] The first through-opening 6 has a first leg side 10, the imaginary extension 11 of which intersects the separation plane 4 at an acute angle 12. A second leg side 13 of the first through-opening 6 runs parallel to the first leg side 10. An imaginary extension 14 of the second leg side 13 intersects the separation plane 4 radially further outward than the imaginary extension 11 of the first leg side 10. The first through-opening 6 has an edge 15 that connects an end 16 of the first leg side 10 facing away from the separation plane 4 with an end 17 of the second leg side 13 facing away from the separation plane 4.

[0030] Fig. 3 is a detailed view of the edge 15 of the first through opening 6.

[0031] The edge 15 has an equidistant section 18 that runs equidistantly from an outer contour 19 of the rotor lamination 1. A distance 20 between the equidistant section 18 and the outer contour 19 is therefore constant in the radial direction over a certain angular range in the circumferential direction. The length of a chord of the equidistant section essentially corresponds to the distance between the limb sides 10, 13.

[0032] The edge 15 further comprises, in its transition into the equidistant section 18 as seen from the first leg side 10, a projection 21 pointing into the through-opening 6 and a recess 22 between the projection 21 and the equidistant section 18. The recess 22 is delimited by an imaginary line 23 which runs parallel to the first leg side 10 and the separation plane 4 (see Fig. 2 ) cuts radially further inward than the imaginary extension 11 of the first leg side 10. Between the projection 21 and the recess 22, the edge 15 has a straight section 24 which runs parallel to the imaginary extension 11 of the first leg side 10, but can alternatively also be oblique. A distance between the straight section 24 and the imaginary line 23 is approximately 1.3 times the distance of the straight section 24 from the imaginary extension 11 of the first leg side 10. Between the recess 22 and the equidistant section 18, the edge 15 has a further straight section 25 which extends along the imaginary line 23.

[0033] Transitions from the end 16 of the first leg section into the projection 21, from the projection 21 into the straight section 24, from the straight section 24 into the recess 22, from the recess 22 into the straight section 25, and from the straight section 24 into the equidistant section 18 are each formed by a rounding whose curve radius is smaller than that of the equidistant section 18. Such a rounding also forms the transition from the end 17 of the second leg side 13 into the equidistant section 18.

[0034] Again with reference to Fig. 2 The second through-opening 7 has a first leg side 26, the imaginary extension 27 of which intersects the separation plane 4 at a radially outwardly open acute angle 28 radially further outward than the second leg side 13 of the first through-opening 6. In this case, the angle 28 is greater than the angle 12. A second leg side 29 of the second through-opening 7 runs parallel to the first leg side 26. An imaginary extension 30 of the second leg side 29 intersects the separation plane 4 radially further outward than the imaginary extension 27 of the first leg side of the second through-opening 7.

[0035] The following comparative examples of a rotor lamination 1 differ from the first embodiment according to Fig. 1 bis Fig. 3 only by the design of the edge 15, so that all previous statements on the embodiment can be transferred to the comparative examples, unless otherwise described below.

[0036] Fig. 4 is a detailed view of the edge 15 of the first through-opening 6 of the comparative example of the rotor lamination 1. The recess 22 extends here to the imaginary extension 11 of the first leg side 10. The chord of the equidistant section 18 is thus somewhat shorter than in the exemplary embodiment.

[0037] Fig. 5 is a detailed view of the edge 15 of the first through-opening 6 of the second comparative example of the rotor lamination 1. Here, the edge 15 runs between the projection 21 and the equidistant section 18 along a straight section 31, which runs parallel to the imaginary extension 11 of the first leg side 10, but can alternatively also be oblique. Transitions from the projection 21 to the straight section 31 and from the straight section 31 to the equidistant section 18 are each formed by a rounded portion whose curve radius is smaller than that of the equidistant section 18. The chord of the equidistant section 18 is somewhat shorter than in the first comparative example.

[0038] Fig. 6 is a schematic diagram of an embodiment of an electrical machine 32, comprising a stator 33 and an embodiment of a rotor 34 mounted within the stator 33.

[0039] The rotor 34 comprises an embodiment of a laminated core 35 formed from a plurality of layered and laminated rotor laminations 1 according to the previously described embodiment. The through-openings 6 to 9 of a respective rotor lamination are arranged congruently one above the other, forming magnetic pockets of the rotor lamination core 35 for permanent magnets 36 of the rotor 34.

[0040] Fig. 7 is a plan view of a half-sector 3a of a rotor lamination 1a according to the prior art, in which an edge 15a of a through-opening 6a clearly does not have an equidistant section. Otherwise, the rotor lamination 1a essentially corresponds to the exemplary embodiment of the rotor lamination 1.

[0041] Simulation has shown that during rotating operation at a speed of 16,000 rpm< a Fig. 6 In the corresponding electrical machine, which is developed on the basis of the rotor lamination 1a, a maximum mechanical stress of approximately 424 MPa is present in a bridge region 37 between the edge 15a and an outer contour 19a of the rotor lamination 1a. In contrast, the maximum mechanical stress in such a bridge region is approximately 410 MPa in the second comparative example, approximately 370 MPa in the first comparative example, and approximately 337 MPa in the exemplary embodiment, so that the equidistant sections 18 can achieve reductions in the maximum mechanical stress of 3.3 percent, 12.7 percent, and 20.5 percent, respectively.

[0042] Fig. 8 is a schematic diagram of an embodiment of a vehicle 38, comprising embodiment of an electric machine 32 according to Fig. 6 , which is configured to drive the vehicle 38. The vehicle 38 may be a battery electric vehicle (BEV) or a hybrid vehicle.

Claims

1. Rotor sheet (1), which is subdivided into a plurality of equally sized and equidistantly arranged sectors (2a-2h), each having a first half-sector (3) and a second half-sector (5) separated from the first half-sector (3) by a separation plane (4), wherein a through-opening (6) is formed in the first half-sector (3), which comprises: • a first leg side (10), the imaginary extension (11) of which intersects the separation plane (4) at an acute angle (12) that opens radially outward, • a second leg side (13), which runs parallel to the first leg side (10), and the imaginary extension (14) of which intersects the separation plane (4) radially further outward than the imaginary extension (11) of the first leg side (10), and • an edge (15) connecting ends (16, 17) of the leg sides (10, 13) that face away from the separation plane (4), wherein the edge (15) comprises: (i) a non-point-shaped equidistant section (18), which runs equidistantly to an outer contour (19) of the rotor sheet (1), (ii) in its transition to the equidistant section (18) viewed from the first leg side (10), a protrusion (21) pointing into the through-opening (6), and (iii) in its transition to the equidistant section (18) viewed from the first leg side (10), a recess (22) pointing away from the through-opening (6), wherein a further through-opening (8), which is mirror-symmetrical to the through-opening (6) with respect to the separation plane (4), is formed in the second half-sector (5), characterized in that the recess (22) is bounded by an imaginary line (23), which runs parallel to the first leg side (10) and intersects the separation plane (4) radially further inward than the imaginary extension (11) of the first leg side (10), wherein the distance between an imaginary line which is parallel to the first leg side (10) and to which the protrusion (21) extends into the through-opening (6), and an imaginary line (23) which is parallel to the first leg side (10) and to which the recess (22) extends is at least 1.1 times and at most 2 times the distance between the imaginary line which is parallel to the first leg side (10) and to which the protrusion (21) extends into the through-opening (6) and the imaginary extension (11) of the first leg side (10).

2. Rotor sheet according to claim 1, wherein the distance between the imaginary line which is parallel to the first leg side (10) and to which the protrusion (21) extends into the through-opening (6), and the imaginary line (23) which is parallel to the first leg side (10) and to which the recess (22) extends is at least 1.2 times the distance between the imaginary line which is parallel to the first leg side (10) and to which the protrusion (21) extends into the through-opening (6) and the imaginary extension (11) of the first leg side (10).

3. Rotor sheet according to claim 2, wherein the distance between the imaginary line which is parallel to the first leg side (10) and to which the protrusion (21) extends into the through-opening (6), and the imaginary line (23) which is parallel to the first leg side (10) and to which the recess (22) extends is at least 1.3 times the distance between the imaginary line which is parallel to the first leg side (10) and to which the protrusion (21) extends into the through-opening (6) and the imaginary extension (11) of the first leg side (10).

4. Rotor sheet according to one of the preceding claims, wherein the distance between the imaginary line which is parallel to the first leg side (10) and to which the protrusion (21) extends into the through-opening (6), and the imaginary line (23) which is parallel to the first leg side (10) and to which the recess (22) extends is at most 1.7 times the distance between the imaginary line which is parallel to the first leg side (10) and to which the protrusion (21) extends into the through-opening (6) and the imaginary extension (11) of the first leg side (10).

5. Rotor sheet according to claim 3, wherein the distance between the imaginary line which is parallel to the first leg side (10) and to which the protrusion (21) extends into the through-opening (6), and the imaginary line (23) which is parallel to the first leg side (10) and to which the recess (22) extends is at most 1.4 times the distance between the imaginary line which is parallel to the first leg side (10) and to which the protrusion (21) extends into the through-opening (6) and the imaginary extension (11) of the first leg side (10).

6. Rotor sheet according to one of the preceding claims, wherein the protrusion (21) lies between the first leg side (10) and the recess (22).

7. Rotor sheet according to one of the preceding claims, wherein the edge (15) between the recess (22) and the equidistant section (18) comprises a straight section (25), preferably running parallel to the imaginary extension (11) of the first leg side (10).

8. Rotor sheet according to one of the preceding claims, wherein the edge (15) transitions into the equidistant section (18) with a smaller curve radius than that of the equidistant section (18).

9. Rotor sheet according to one of the preceding claims, wherein the edge (15) transitions from the second leg side (13) into the equidistant section (18) via a rounding, whose curve radius is smaller than that of the equidistant section (18).

10. Rotor sheet according to one of the preceding claims, wherein a second through-opening (7) is formed in the first half-sector (3), wherein the second through-opening (7) comprises a first leg side (26), the imaginary extension (27) of which intersects the separation plane (4) at an acute angle (28) that opens radially outward further outward than the imaginary extension 14) of the second leg side (13), and a second leg side (29), which runs parallel to the first leg side (26), and the imaginary extension (30) of which intersects the separation plane (4) radially further outward than the imaginary extension (27) of the first leg side (26), wherein a further through-opening (9), which is mirror-symmetrical to the second through-opening (7) with respect to the separation plane (4), is formed in the second half-sector (5).

11. Rotor sheet package (35), comprising a plurality of rotor sheets (1) according to one of the preceding claims, which are stacked and connected to each other such that a respective through-opening (6-9) of the rotor sheets (1) forms a magnet pocket extending in the axial direction.

12. Rotor (34), comprising a rotor sheet package (35) according to claim 11, wherein a permanent magnet (36) is arranged a respective each magnet pocket.

13. Electric machine (32), comprising a rotor (34) according to claim 12.

14. Vehicle (38), comprising an electric machine (32) according to claim 13, which is designed to drive the vehicle (38).