Permanentmagnetrotor

Abstract

Permanent magnet rotor (1) of an electric motor, comprising a laminated core (2) composed of two partial lamination stacks (3, 4), a plurality of permanent magnets (6) force-fitted in magnet pockets (5) of the laminated core, wherein these extend over both partial lamination stacks (3, 4), wherein deflectable lamination tongues (7), which maintain the force fit, are deflected in a first axial direction in a first partial lamination stack (3) and in a second partial lamination stack (4) are deflected in a second axial direction, which is opposite to the first direction, wherein the partial lamination stacks (3, 4) consist of stamped sheets and the permanent magnets are pressed into the magnet pockets (5) in the stamping direction, and wherein the lamination tongues (7a, 7b and 7c) have side edges (13a, 13b, 13c) and are rounded at the corners at their free ends, wherein the side edges (13b) at the lamination tongue (7b) run parallel, at the sheet metal tongues (7a and 7c) the side edges (13a,13b) run towards each other..,

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).

[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] From DE 10 2015 222 271 A1, a generic permanent magnet rotor is known in which the magnets are arranged tangentially. Two or more rotor sections are present, which can 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 can 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] DE 10 2017 217 282 B3 discloses a permanent magnet rotor of an electric motor, with a magnetically conductive magnetic core, which has a plurality of magnet receptacles for radially arranged and substantially tangentially magnetized permanent magnet pieces, wherein the magnetic core is axially composed of two sub-cores and permanent magnet pieces are mechanically fastened in a part of the magnet receptacles of each sub-core, which, when the two sub-cores are joined together, are fitted into magnet receptacles of the respective other sub-core by forming a clearance or transition fit.

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

[0006] DE 11 2013 002 622 T5 discloses the assembly of a rotor core by inserting core halves into one another.

[0007] The assembly of a rotor core by inserting core halves into one another is known from US patent 2014 / 0285049A1.

[0008] 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.

[0009] This problem is solved according to the invention by the features of claim 1 and the method according to claim 15.

[0010] Deflectionable lamination tongues (7), which maintain the force-fit between the permanent magnets and the magnet pockets, are deflected in a first axial direction in a first lamination stack (3) and in a second axial direction in a second lamination stack (4), the first direction being opposite to the second. This prevents the magnets from shifting due to temperature fluctuations, which can cause directed micro-movements, because their directions of movement are opposite to each other. The lamination stacks (3, 4) consist of stamped sheets. To achieve a sliding press-fit process, the permanent magnets are pressed into the magnet pockets (5) in the direction of stamping.

[0011] Further developments of the invention are described in more detail in the dependent claims. According to a first embodiment of the invention, the sheet metal cuts of the two partial sheet metal packages (3, 4) are identical. This eliminates the need for a second stamping tool and enables economical production.

[0012] In a further development of this embodiment, the sheet metal tabs (7) project into recesses for magnetic pockets (5), and the sheet metal cut has recesses for magnetic pockets (5) with sheet metal tabs (7) and recesses for magnetic pockets (5) without sheet metal tabs. This allows for variations without increasing the number of sheet metal cuts.

[0013] In one variant, the sheets of the sheet metal section in the partial sheet metal stack (3, 4) are twisted relative to each other, so that within a magnet pocket (5) sheet metal tabs (7) and free spaces alternate in the axial direction. The free spaces allow the sheet metal tabs to bend solely due to their own elasticity when the magnets are pressed in.

[0014] In a second embodiment, the sheet metal cut of the partial sheet metal stacks (3, 4) consists of at least two different sheet metal cuts, wherein the sheet metal tongues (7) are not present in all sheet metal cuts and / or differently shaped sheet metal tongues are present in different sheet metal cuts. In this way, gaps can also be created between the sheet metal tongues. By varying the layering, the pressing force can be specifically adjusted via the pressing path of the permanent magnets.

[0015] Because the lamination tabs are deflected by the permanent magnet, the outer lamination tabs can barely grip the permanent magnet. Therefore, it is designed so that, viewed from one axial end of the rotor lamination stack, there are no lamination tabs in the first, first two, first three, first four, or first five laminations. This measure also simplifies assembly, as the permanent magnet can initially be inserted into the magnet pocket with some play before being pressed radially outwards.

[0016] 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.

[0017] 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 made significantly smaller than the opposing edge radii of the permanent magnets (6).

[0018] The sheet metal tongues can have the same width at the base as at their radially outer tongue end.

[0019] The bending forces on the sheet metal tabs 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 tabs (7) should taper towards their free end. This results in a more homogeneous force distribution along the length of the sheet metal tabs. This taper can be adjusted as desired.

[0020] The width of the magnetic pockets (5) can be significantly larger in the radial direction than in the tangential direction or vice versa.

[0021] 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.

[0022] 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.

[0023] 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 a partial sheet metal package equipped with permanent magnets, Fig. 4 a sectional view of the assembled partial sheet metal package according to Fig. 3, Fig. 5 two partial sheet metal packages with partially equipped magnetic pockets, Fig. 6 a selection of different sheet metal tongues, Fig. 7 a spatial representation of a mounted permanent magnet rotor, Fig. 8 a sectional view of the permanent magnet rotor according to Fig. 7, Fig. 9 a second embodiment of a fully populated partial sheet metal package with an unpopulated partial sheet metal package, Fig. 10 a spatial representation of an assembled permanent magnet motor according to the second embodiment, Fig. 11 a sectional view of a fully assembled partial sheet metal package according to the second embodiment, Fig. 12 a sectional view of the permanent magnet rotor according to Fig. 10 and Fig. 13 a variant of the second embodiment.

[0024] Note: Reference numerals with and without an index denote identical details in the drawings and the drawing description. These refer to the use of a different embodiment, the prior art, and / or indicate that 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.

[0025] Fig. 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, so that a gap 12 remains 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.

[0026] Fig. Figure 2 shows a simplified sectional view (without resolution of the sheet layers) of the partial sheet metal package 3. Fig. 1, where 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.

[0027] Fig. Figure 3 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.

[0028] Fig. Figure 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.

[0029] Fig. Figure 5 shows two partial lamination stacks 3a, 4a, which are partially equipped with permanent magnets 6a. In the intermediate state shown, only every second magnet pocket 5a contains a permanent magnet 6a. The two partial lamination stacks 3a, 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, 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. Projections 14a are provided in a central recess 15a, which serve to clamp a shaft to be accommodated. 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 shows the poles 8a, the pole shoes 9a

[0030] Fig. Figure 6 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.

[0031] Fig. Figure 7 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.

[0032] Fig. Figure 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.

[0033] Fig. Figure 9 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.

[0034] Fig. Figure 10 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.

[0035] Fig. Figure 11 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.

[0036] Fig. Figure 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.

[0037] Fig. Figure 13 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 1 permanent magnet rotor 2 sheet metal packages 3 first partial sheet metal package 4 second partial sheet metal package 5 magnetic pockets 6 permanent magnets 7 sheet metal tongue 8 pole 9 pole shoe 10 central ring 11 Bridge 12 Free space 13 Side edge 14 lead 15 central recess 16 Breakthrough 17 Joining aid

Claims

[1] 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) frictionally received in magnet pockets (5) of the laminated core, said permanent magnets extending over both partial laminated cores (3, 4), wherein deflectable laminated core tongues (7), which maintain the frictional connection, are deflected in a first axial direction in a first partial laminated core (3) and are deflected in a second axial direction in a second partial laminated core (4), which is opposite to the first direction, wherein the partial laminated cores (3, 4) consist of punched sheets and the permanent magnets are pressed into the magnet pockets (5) in the punching direction and wherein the laminated core tongues (7a, 7b and 7c) have side edges (13a, 13b, 13c) and are rounded at their free end in the corners, wherein the side edges (13b) run parallel to the sheet metal tongue (7b),the side edges (13a, 13b) of the sheet metal tongues (7a and 7c) converge towards each other. [2] Permanent magnet rotor according to claim 1, characterized by that the lamination cuts of the two partial lamination packages (3, 4) are identical. [3] Permanent magnet rotor according to claim 2, characterized by that the sheet metal tongues (7) protrude into recesses for magnetic pockets (5) and the sheet metal cut has recesses for magnetic pockets (5) with sheet metal tongues (7) and recesses for magnetic pockets (5) without sheet metal tongues. [4] Permanent magnet rotor according to claim 3, characterized by that the sheets of the sheet cut in the partial sheet package (3, 4) are rotated against each other, so that sheet tongues (7) and free spaces alternate in the axial direction within a magnetic pocket (5). [5] Permanent magnet rotor according to claim 1, characterized bythat the lamination section of the partial lamination packages (3, 4) consists of at least two different lamination sections, wherein the lamination tongues (7) are not present in all lamination sections and / or differently designed lamination tongues are present in different lamination sections. [6] Permanent magnet rotor according to claim 5, characterized by that in a partial laminated core (3, 4) one or more first laminated core cuts and one or more second laminated core cuts alternate with one another. [7] Permanent magnet rotor according to at least one of the preceding claims, characterized by that, viewed from an axial end of the rotor lamination stack, there are no lamination tongues in the first or in the first two or in the first three or in the first four or in the first five laminations. [8] Permanent magnet rotor according to at least one of the preceding claims, characterized bythat the sheet metal tongues (7) extend radially outwards and push the permanent magnets (6) radially outwards accordingly, wherein the permanent magnets (6) are supported radially on poles (8) or on pole shoes (9) of the partial sheet stack (3, 4). [9] Permanent magnet rotor according to claim 8, characterized by that the radii in the transition area between the pole shoes (9) and the adjacent side surfaces of the magnet pockets (5) are significantly smaller than the opposite edge radii of the permanent magnets (6). [10] Permanent magnet rotor according to at least one of the preceding claims, characterized by that one or more sheet metal tongues (7) have the same width at their radially inner base as at their radially outer tongue end. [11] Permanent magnet rotor according to at least one of the preceding claims, characterized bythat one or more sheet metal tongues (7) are slightly wider at their radially inner base than at their radially outer tongue end. [12] Permanent magnet rotor according to at least one of the preceding claims, characterized by that one or more sheet metal tongues (7) are / are significantly wider at their radially inner base than at their radially outer tongue end. [13] Permanent magnet rotor according to at least one of the preceding claims, characterized by that the width of the magnetic pockets (5) is significantly larger in the radial direction than in the tangential direction. [14] Permanent magnet rotor according to at least one of the preceding claims, characterized by that the width of the magnetic pockets (5) is significantly larger in the tangential direction than in the radial direction. [15] Method for producing 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) frictionally received in magnet pockets (5) of the laminated core, said permanent magnets extending over both partial laminated cores (3, 4), with the following method steps: a) providing two partial laminated cores (3, 4) and a plurality of permanent magnets (6); b) axially pressing the permanent magnets (6) into the first partial laminated core, so that a first section of the permanent magnets (6) is received in magnet pockets (5) of the first partial laminated core in the punching direction and a second section of the permanent magnets (6) protrudes axially freely from the magnet pockets (5); c) axially pressing the second partial laminated core (4) onto the free ends of the permanent magnets (6).

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