PERMANENTMAGNETROTOR

Description

[0001] The invention relates to a permanent magnet rotor (1) of an electric motor, comprising a laminated core (2) composed of two partial laminated cores (3, 4), a plurality of permanent magnets (6) force-fitted into magnetic pockets (5) of the laminated core, wherein these extend over both partial laminated cores (3, 4), and a method for manufacturing such a permanent magnet rotor.

[0002] In many known permanent magnet rotors, the permanent magnets exhibit a radial or tangential orientation within magnetic pockets. Significantly higher magnetic efficiencies can be achieved with radially arranged permanent magnets, which is why they are increasingly being used.

[0003] A generic permanent magnet rotor is known from DE 10 2015 222 271 A1, in which the magnets are arranged tangentially. Two or more rotor sections are present, which may also be designed as a laminated core, and in which the permanent magnets extend over these multiple rotor sections. One of the two rotor sections may also be rotated by an angle of 180° with respect to an axis of rotation perpendicular to the rotor axis. The known document does not specify how the permanent magnets are held axially within the magnet pockets.

[0004] JP 2015 154 665 A discloses a permanent magnet rotor of an electric motor, comprising a laminated core composed of two partial laminated cores, a plurality of permanent magnets force-fitted in magnet pockets of the laminated core, wherein these extend over both partial laminated cores, wherein deflectable lamination tongues, which maintain the force fit, are deflected in a first axial direction in a first partial laminated core and are deflected in a second axial direction in a second partial laminated core, which is opposite to the first direction.

[0005] From DE 10 2007 029 719 A1, rotor laminations are known in which only every fifth magnet pocket has a clamping lug. However, this is only used to represent free laminations by twisting the laminations.

[0006] DE 10 2015 222271 A1 discloses a rotor for an electric machine comprising at least a first rotor body and a second, axially offset rotor body. The two rotor bodies differ in their geometry and / or azimuthal orientation relative to each other. At least a portion of the receiving pockets of the first rotor body is axially aligned with at least a portion of the receiving pockets of the second rotor body, and a common, one-piece magnet body is inserted into each of these mutually aligned receiving pockets, the magnet body at least partially penetrating both rotor bodies.

[0007] DE 10 2014 225260 A1 describes a laminated core for a rotor of an electric machine, which has pockets distributed around the outer circumference of the laminated core for receiving permanent magnets. Each pocket has at least one resilient retaining element arranged on the outer surface of the pocket facing the outer circumference.

[0008] JP 2000 295824 A refers to a method for assembling a rotor with a shaft fixed in the center of a core consisting of several stacked metal plates. The method comprises the following steps: 1. Forming a hardened layer on the outer periphery of the shaft. 2. Pressing the shaft into the bore formed in the center of the core. Thus, this method enables improved concentricity between the shaft and the core of the rotor.

[0009] DE 10 2006 046 231 A1 describes a rotor lamination of an electric motor rotor with a center of gravity, an inner contour, and an outer contour. The radial distance of the inner contour from the center of gravity varies between minimum and maximum values ​​depending on the tangential angle. The radial distance of the outer contour is greater than the maximum value of the inner contour, regardless of the tangential angle. At the tangential angles with the minimum value of the inner contour, intermediate recesses are provided, leaving elastically yielding webs between the recesses and the inner contour.

[0010] The object of the invention is to ensure a secure and durable fastening of the permanent magnets in the magnetic pockets of a generic permanent magnet rotor, while enabling the simplest possible assembly.

[0011] This problem is solved according to the invention by the features of claim 1 and the method according to claim 9.

[0012] The problem is solved by a permanent magnet rotor of an electric motor, comprising a laminated core (2) composed of two partial laminations, and a plurality of permanent magnets force-fitted into magnet pockets of the laminated core, with these magnets extending over both partial laminations. Deflectionable lamination tabs, which maintain the force-fit between the permanent magnets and the magnet pockets, are deflected in a first axial direction in a first partial lamination and in a second partial lamination in a second axial direction, the first direction being opposite to the second. This measure prevents the magnets from wandering due to temperature fluctuations, which can cause directed micro-movements, because their directions of movement are opposite to each other. The partial laminations consist of stamped sheets.To achieve a smooth pressing-in process, the permanent magnets are pressed into the magnet pockets in the direction of the stamping. The sheet metal sections of the partial laminations consist of at least two different sections, whereby the sheet metal tongues are not present in all sections and differently shaped sheet metal tongues are present in different sections. In this way, gaps can also be created between the sheet metal tongues. By varying the layering, the pressing force can be precisely adjusted via the pressing path of the permanent magnets. One or more sheet metal tongues have the same width at their radially inner base as at their radially outer end. One or more sheet metal tongues are slightly wider at their radially inner base than at their radially outer end.

[0013] The bending forces on the metal tabs are generally greatest at the base, near a central ring. To ensure that the bending forces are as independent as possible from the radial contact position with a permanent magnet, the metal tabs should be slightly tapered towards their free end or slightly wider at the base than at their radially outer end. This results in a more homogeneous force distribution along the length of the metal tabs.

[0014] Further developments of the invention are described in more detail in the dependent claims. Since the lamination tabs are deflected by the permanent magnet, the outer lamination tabs can hardly grip the permanent magnet. Therefore, it is provided that, viewed from an axial end of the rotor lamination stack, no lamination tabs are present in the first, the first two, the first three, the first four, or the first five laminations. This measure also facilitates assembly because the permanent magnet can initially be inserted into the magnet pocket with some play before being pressed radially outwards.

[0015] It is advantageous if the lamination tongues (7) extend radially outwards and the permanent magnets (6) extend correspondingly radially outwards, bearing radially against poles (8) or pole shoes (9) of the partial lamination stack (3, 4). This is particularly useful for radially arranged permanent magnets with tangential magnetization, because no magnetic field lines of the main field run in the region of the lamination tongues (7). Clearances are required around the lamination tongues to allow them to deflect. These clearances also form flux barriers, minimizing stray flux effects and magnetic short circuits.

[0016] Due to the manufacturing process, radii are always present in the area of ​​the pole shoes and at the edges of the permanent magnets. To ensure that the permanent magnets can be precisely aligned during assembly, it was proposed that the radii in the transition area between the pole shoes (9) and the adjacent side surfaces of the magnet pockets (5) be significantly smaller than the opposing edge radii of the permanent magnets (6).

[0017] The bending forces on the sheet metal tongues are generally greatest at the base, near a central ring (10). To ensure that the bending forces are as independent as possible from the radial contact position with a permanent magnet, the sheet metal tongues (7) should be significantly tapered towards their free end or significantly wider at the base than at their radially outer end. This results in a more homogeneous force distribution along the length of the sheet metal tongues. This can be adjusted as desired by varying the degree of tapering.

[0018] The width of the magnetic pockets (5) can be significantly larger in the radial direction than in the tangential direction or vice versa.

[0019] A second solution is provided by the following process steps: a) providing two partial lamination stacks (3, 4) and a plurality of permanent magnets (6); b) axially pressing the permanent magnets (6) into the first partial lamination stack, such that a first section of the permanent magnets (6) is received in magnet pockets (5) of the first partial lamination stack and a second section of the permanent magnets (6) projects axially freely from the magnet pockets (5); c) axially pressing the second partial lamination stack (4) onto the free ends of the permanent magnets (6). This procedure deflects the lamination tongues in opposite directions, so that the magnets do not migrate due to temperature cycling.

[0020] During assembly, the permanent magnets can be pre-magnetized or, in one variant, magnetized only in a partial package, provided that only every second magnetic pocket is equipped with a permanent magnet.

[0021] Exemplary embodiments of the invention are explained in more detail below with reference to the drawing. The drawing shows: Fig. 1 a partial sheet metal package, Fig. 2 a sectional view through the partial sheet metal package according to Fig. 1 Fig. 3 shows a partial lamination stack equipped with permanent magnets, Fig. 4 shows a sectional view of the equipped partial lamination stack according to Fig. 3 Fig. 5 two partial lamination stacks with partially populated magnet pockets, Fig. 6 a selection of different lamination tongues, Fig. 7 a spatial representation of an assembled permanent magnet rotor, Fig. 8 a sectional view of the permanent magnet rotor according to Fig. 7 Fig. 9 shows a second embodiment of a fully populated partial lamination stack with an unpopulated partial lamination stack; Fig. 10 shows a spatial representation of an assembled permanent magnet motor according to the second embodiment; Fig. 11 shows a sectional view of a fully populated partial lamination stack according to the second embodiment; Fig. 12 shows a sectional view of the permanent magnet rotor according to Fig. 10 and Fig. 13 shows a variant of the second embodiment.

[0022] Note: Reference numerals with and without an index denote identical details in the drawings and the drawing description. These refer to use in a different embodiment, the prior art, and / or because the detail is a variant. For the sake of simplicity, the claims, the introductory description, the list of reference numerals, and the summary contain only reference numerals without an index.

[0023] Fig. 1 Figure 1 shows a partial lamination stack 3, consisting of a multitude of differently shaped laminations. A first lamination section has radially extending poles 8 connected to a central ring via webs 11, which are separated from each other by recesses forming magnet pockets 5. In a second lamination section, each magnet pocket 5 additionally has radially extending lamination tongues 7 extending from the central ring. The two lamination sections alternate, leaving a gap 12 between two axially adjacent lamination tongues 7. The poles 8 have tangentially adjoining pole shoes 9, which serve as a radial stop for permanent magnets to be mounted.

[0024] Fig. 2 shows a simplified sectional view (without resolution of the sheet metal layers) of the partial sheet metal package 3. Fig. 1 , whereby the free spaces 12 between the sheet metal tongues 7 are more clearly visible. Also shown are the poles 8, the pole shoes 9, the central ring 10 and the webs 11.

[0025] Fig. 3 Figure 1 shows a partial lamination stack 3 equipped with permanent magnets 6, with the poles 8, the pole shoes 9, the lamination tongues 7, the central ring 10, the webs 11 and the clearances 12. Since the permanent magnets extend over two partial lamination stacks 3, in this view they project axially beyond the first partial lamination stack 3 by half their length.

[0026] Fig. 4 shows a simplified sectional view (without resolution of the sheet layers) of the partial sheet metal package 3 equipped with permanent magnets 6 according to Fig. 3 , with the central ring 10, the sheet metal tongues 7, the webs 11, the clearances 12, the poles 8 and the pole shoes 9. The permanent magnets 6 are radially clamped without play between the sheet metal tongues 7 and the pole shoes. The sheet metal tongues 7 are bent in the direction of insertion of the permanent magnets 6. The sheet metal tongues can be elastically deformed or elastically and plastically deformed.

[0027] Fig. 5 Figure 1 shows two partial lamination stacks 3a and 4a, each partially equipped with a permanent magnet 6a. In the intermediate state shown, only every second magnet pocket 5a contains a permanent magnet 6a. The two partial lamination stacks 3a and 4a are identical and rotated 180° relative to each other about an axis perpendicular to the rotor axis. Additionally, the two partial lamination stacks 3a and 4a are pivoted about the rotor axis by one rotor pole pitch. The lamination tongues 7a are visible in the magnet pockets 5a that do not contain permanent magnets. A central recess 15a contains projections 14a, which serve to clamp a shaft to be inserted. These projections also have clearances and function similarly to the spring tongues 7a. No projections 14a are provided at the beginning of the lamination stack to facilitate the insertion of the shaft. When pressing in the permanent magnets, they must be well guided.Partially assembled sheet metal packages are particularly suitable for smaller sizes because more space remains between the permanent magnets for the assembly equipment. Further details are available in... Fig. 5 The poles are shown in 8a, the pole shoes in 9a.

[0028] Fig. 6 Figure 7a shows a selection of different sheet metal tongues 7a, 7b, and 7c. Sheet metal tongues 7a, 7b, and 7c have side edges 13a, 13b, and 13c, respectively, and are rounded at the corners of their free ends. The side edges 13b run parallel on sheet metal tongue 7b. On sheet metal tongues 7a and 7c, the side edges 13a and 13b converge, with a smaller angle on sheet metal tongue 7a and a larger angle on sheet metal tongue 7c. The larger the angle between the side edges, the lower the spring constant of the sheet metal tongue. With the parallel side edges 13b on sheet metal tongues 7b, high contact forces are quickly achieved with a small spring deflection when bent. The sheet metal tongues 7c, with their larger angle, exhibit softer spring characteristics. This allows for a wider tolerance range.The sheet metal tongues 7a, which have a shallower angle on their side edges 13a, generate similar forces to those produced by the sheet metal tongues 7c; however, the spring action prevents the generation of larger lateral forces. It is also possible to vary the width of the sheet metal tongues in the area of ​​the central ring to influence the spring force.

[0029] Fig. 7 Figure 1 shows a spatial representation of an assembled permanent magnet rotor 1, with a laminated core 2, the first partial laminated core 3, the second partial laminated core 4, the permanent magnets 6, the lamination tongues 7, the central ring 10, the poles 8, the pole shoes 9, the webs 11 and the clearances 12. The permanent magnets 6 extend over both partial laminated cores 3 and 4.

[0030] Fig. 8 shows a simplified sectional view (without resolution of the sheet metal layers) of the permanent magnet rotor according to Fig. 7 , with the partial lamination stacks 3 and 4, the lamination tongues 7, the permanent magnets 6, the central ring 10, the webs 11, the clearances 12, the poles 8 and the pole shoes 9. As can be clearly seen, the lamination tongues 7 in the partial lamination stack 3 are deflected in the opposite direction to the lamination tongues in the partial lamination stack 4.

[0031] Fig. 9 Figure 1 shows a second embodiment of a fully populated partial lamination stack 3d with an unpopulated partial lamination stack 4d, with tangentially arranged permanent magnets 6d which are received in magnet pockets 5d of the first partial lamination stack 3d.

[0032] Fig. 10 Figure 1 shows a spatial representation of an assembled permanent magnet motor 1d according to the second embodiment, with the first partial lamination stack 3d, the second partial lamination stack 4d, which together form the lamination stack 2d, the magnet pockets 5d, the mounted permanent magnets 6d, the lamination tongues 7d, the central recess 15d, the central ring 10d, the webs 11d between the central ring 10d and poles 8d and the openings 16d.

[0033] Fig. 11 Figure 1 shows a sectional view of a fully assembled partial lamination stack 3d according to the second embodiment, with the poles 8d, the permanent magnets 6d, the central ring 10d, the lamination tongues 7d separated by spaces 12d and the central recess 15d.

[0034] Fig. 12 shows a sectional view of the permanent magnet rotor 1d according to Fig. 10 , with the partial lamination stacks 3d and 4d, the poles 8d, the permanent magnets 6d, the lamination tongues 7d, the clearances 12d, the central ring 10d and the central recess 15d.

[0035] Fig. 13 Figure 1 shows a variant of the second embodiment, comprising the first partial lamination stack 3e, the permanent magnets 6e, the poles 8e, the lamination tongues 7e, the clearances 12e, the central ring 10e, the central recess 15e, and joining aids 17e in the form of several initial laminations that do not have lamination tongues. This facilitates the assembly of the permanent magnets 6e. Reference symbol list

[0036] 1 Permanent magnet rotor 2 Sheet metal stack 3 First partial sheet metal stack 4 Second partial sheet metal stack 5 Magnet pocket 6 Permanent magnet 7 Sheet metal tongue 8 Pole 9 Pole shoe 10 Central ring 11 Web 12 Clearance 13 Side edge 14 Projection 15 Central recess 16 Opening 17 Joining aid

Claims

1. A permanent-magnet rotor (1) of an electric motor, with a laminated core (2) composed of two partial laminated cores (3, 4), a plurality of permanent magnets (6) received in a force-fit in magnet pockets (5) of the laminated core, wherein said permanent magnets extend over both partial laminated cores (3, 4), wherein deflectable lamination tongues (7) which maintain the force-fit connection in a first partial laminated core (3) are deflected in a first axial direction, and in a second partial laminated core (4) are deflected in a second axial direction which is opposed to the first direction, wherein the partial laminated cores (3, 4) consist of stamped metal sheets, characterised in that the permanent magnets are pressed into the magnet pockets (5) in the stamping direction, in that the lamination cuts of the partial laminated cores (3, 4) consist of at least two different lamination cuts, with the lamination tongues (7) not being present in all the lamination cuts, and differently formed lamination tongues being present in different lamination cuts, in that one or more lamination tongues (7) have the same width at its / their radially inner base(s) as at its / their radially outer tongue end(s), and in that one or more lamination tongues (7) is / are formed to be somewhat wider at its / their radially inner base(s) than at its / their radially outer tongue end(s).

2. A permanent-magnet rotor according to claim 1, characterised in that alternately one or more first lamination cuts and one or more second lamination cuts alternate with each other in a partial laminated core (3, 4).

3. A permanent-magnet rotor according to at least one of the preceding claims, characterised in that no lamination tongues are present, viewed from one axial end of the laminated rotor core, in the first or in the first two or in the first three or in the first four or in the first five laminations.

4. A permanent-magnet rotor according to at least one of the preceding claims, characterised in that the lamination tongues (7) extend radially outwards and urge the permanent magnets (6) correspondingly radially outwards, with the permanent magnets (6) being supported radially on poles (8) or on pole shoes (9) of the partial laminated core (3, 4).

5. A permanent-magnet rotor according to claim 4, characterised in that the radii in the region of transition between the pole shoes (9) and the adjoining side faces of the magnet pockets (5) are considerably smaller than the opposing edge radii of the permanent magnets (6).

6. A permanent-magnet rotor according to at least one of the preceding claims, characterised in that one or more lamination tongues (7) is / are formed to be considerably wider at its / their radially inner base(s) than at its / their radially outer tongue end(s).

7. A permanent-magnet rotor according to at least one of the preceding claims, characterised in that the width of the magnet pockets (5) in the radial direction is considerably greater than in the tangential direction.

8. A permanent-magnet rotor according to at least one of claims 1 to 6, characterised in that the width of the magnet pockets (5) in the tangential direction is considerably greater than in the radial direction.

9. A method for producing a permanent-magnet rotor (1) of an electric motor in accordance with claim 1, with a laminated core (2) composed of two partial laminated cores (3, 4), a plurality of permanent magnets (6) received in a force-fit in magnet pockets (5) of the laminated core, wherein said permanent magnets extend over both partial laminated cores (3, 4), characterised by the following method steps: a) providing two partial laminated cores (3, 4) and a multiplicity of permanent magnets (6); b) axially pressing the permanent magnets (6) into the first partial laminated core, so that a first portion of the permanent magnets (6) is received in magnet pockets (5) of the first partial laminated core and a second portion of the permanent magnets (6) protrudes axially freely out of the magnet pockets (5); c) axially pressing the second partial laminated core (4) onto the free ends of the permanent magnets (6).