Rotor of an electric machine
Patent Information
- Application Number
- EP2023712879
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-04-07
- Filing Date
- 2023-03-20
- Publication Date
- 2025-02-12
AI Technical Summary
The existing rotor designs for electrical machines face limitations in maximizing torque transfer due to the non-aligned teeth of sheet metal lamellas, leading to flexibility and reduced mechanical stiffness in the axial direction.
The rotor design features sheet metal lamellas of the same shape twisted relative to each other, allowing partial overlap of teeth to enhance mechanical support, with axial grooves and uneven groove flanks facilitating a stronger weld connection to prevent lamination fanning and improve durability.
This design increases the maximum transferable torque by providing better mechanical stiffness and reliability, with reduced welding defects and improved long-term durability of the press connection.
Smart Images
Figure 1.1
Abstract
Description
[0001] Description
[0002] title
[0003] Rotor of an electrical machine
[0004] State of the art
[0005] The invention is based on a rotor of an electrical machine according to the preamble of the main claim.
[0006] A rotor of an electrical machine is already known from JP2006217770 A2, having a rotor shaft rotatable about a rotor axis and a rotor laminated core arranged on the rotor shaft, which comprises a core of laminated laminations. A press connection for transmitting torque is provided between the rotor laminated core and the rotor shaft. The laminated laminations each have an inner contour with teeth on an inner circumference facing the rotor shaft to form the press connection. At least one partial core of the rotor laminated core is formed from laminated laminations of the same shape, in particular of identical shape. The laminated laminations of the same shape are rotated relative to one another by a twist angle, at least in the partial core, such that the teeth of the laminated laminations are arranged non-aligned and without overlap with the teeth of adjacent laminated laminations.In this way, gaps are formed between the teeth into which the teeth can bend in the axial direction relative to the rotor axis when forming the press connection.
[0007] Advantages of the invention
[0008] The rotor of an electrical machine according to the invention with the characterizing features of the main claim has the advantage that the maximum transmittable torque of the press connection can be increased by rotating the identically shaped laminations, at least in the partial package, relative to one another in such a way that several, in particular all, teeth of the inner contour of the respective laminations are arranged in a partially overlapping manner with teeth of adjacent laminations. The corresponding teeth are thus arranged in a non-aligned, partially overlapping manner. Due to the partial overlapping of the teeth according to the invention, the individual teeth are better mechanically supported, thus less flexible in the axial direction and therefore mechanically stiffer.
[0009] The measures listed in the subclaims enable advantageous further developments and improvements of the rotor of an electrical machine specified in the main claim.
[0010] According to an advantageous first exemplary embodiment, the inner contour of the identically shaped laminations can each have a plurality of sequences of a toothed section and an intermediate groove. The toothed sections each comprise a group of teeth, with a toothed groove being formed between adjacent teeth of the respective toothed section. The intermediate grooves form a plurality of axial grooves running in the axial direction in the rotor laminated core, with at least one weld seam being provided in at least one of the axial grooves for connecting laminations of the rotor laminated core. In this way, the rotor laminated core can be welded to the inner contour using the press connection according to the invention, thus preventing the laminations of the rotor laminated core from fanning out. The axial grooves are, for example, continuous in the axial direction, at least with regard to the partial core.
[0011] It is also advantageous if the axial grooves each have two uneven, particularly ribbed, groove flanks formed by teeth of the toothed sections projecting into the respective axial groove to varying degrees. The uneven or ribbed groove flanks of the axial grooves are created by the rotation of the laminations. The teeth adjacent to the axial groove extend only far enough into the axial groove to leave an axially continuous groove area without teeth, in which the welded connection can then be made. In this way, the rotor lamination stack can be welded to the inner contour using the press connection according to the invention.
[0012] It is very advantageous if the intermediate grooves are wider in the circumferential direction than the tooth grooves of the toothing sections. This ensures that a sufficiently wide, axially continuous groove area without teeth remains, in which the welded connection can then be made. It is also advantageous if a protruding welding nose is formed on the groove base of each of the intermediate grooves to form the weld seam. This allows better control of the welding of the weld seam. In addition, less welding power can be used, so that less porosity and fewer welding defects occur in the weld seam. Any welding defects that still occur are located outside the rotor yoke, which improves the reliability and long-term load-bearing capacity of the press connection or interference fit.
[0013] According to a second embodiment, the welding noses of the intermediate grooves are formed in a recess of the groove base, whereby welding spatter on the teeth can be avoided.
[0014] Furthermore, it is advantageous if, in the intermediate grooves of the same sheet metal lamination, the position of the welding lugs varies relative to the flanks of the respective intermediate groove, and if the sheet metal laminations are arranged such that the welding lugs of the same axial groove are aligned with each other. In this way, the partial overlap of the teeth of the inner contour with the teeth of adjacent sheet metal laminations according to the invention is achieved.
[0015] It is advantageous if, for a single lamination, the number of toothed sections and the number of intermediate slots each correspond to the number of rotor poles of the rotor. In this way, the rotor lamination stack can be formed from identically shaped laminations, which are punched out, for example, with the same or the same punching tool.
[0016] It is also advantageous if the toothed sections of the respective lamination, with the exception of one of the toothed sections, each have the same number of teeth. This allows the overlap of the teeth and thus the maximum transmittable torque to be increased.
[0017] It is also advantageous if the toothed sections of the respective lamination have an odd number of teeth. This increases the overlap of the teeth and thus the maximum transmittable torque.
[0018] The invention further relates to an electric machine with a rotor according to the invention. Drawing
[0019] Embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description.
[0020] Fig.l shows a sectional view of a rotor of an electrical machine according to the invention,
[0021] Fig.2 is a three-dimensional partial view of an inner contour of the rotor according to the invention according to Fig.1,
[0022] Fig.3 is a two-dimensional view of the inner contour of the rotor according to Fig.l according to a first embodiment,
[0023] Fig.4 is a view of detail A of the inner contour according to Fig.3 according to a first embodiment and
[0024] Fig.5 is a view of detail A of the inner contour according to Fig.3 according to a second embodiment.
[0025] Description of the embodiments
[0026] Fig.l shows a side view of a rotor of an electrical machine according to the invention.
[0027] The rotor 2 of an electrical machine 1 has a rotor carrier 4, in particular a rotor shaft, rotatable about a rotor axis 3, and a rotor lamination stack 5 arranged on the rotor carrier 4. The rotor lamination stack 5 comprises a stack of laminations 6, in particular made of electrical steel. A press connection for transmitting torque is provided between the rotor lamination stack 5 and the rotor carrier 4. A toothed structure is formed on the inner circumference 5i of the rotor lamination stack 5, which interacts with the, for example, cylindrical rotor carrier 4 to form the press connection.
[0028] Fig. 2 shows a three-dimensional partial view of an inner circumference 5i of the rotor according to Fig. 1, designed according to the invention. The laminations 6 each have an inner contour 6i with teeth 7 on an inner circumference facing the rotor carrier 4 for forming the press connection with the rotor carrier 4. At least one partial package of the rotor lamination package 5 is constructed from laminations 6 of the same shape, in particular of identical shape. The laminations 6 of the same shape are punched out, for example, using the same punching tool. The laminations 6 of the same shape are rotated relative to one another, at least in the partial package, by an angle of rotation about the rotor axis 3. The angle of rotation of the laminations 6 can, for example, correspond to an angle resulting from a quotient of 3607 rotor pole number or an integer multiple of the quotient.
[0029] According to the invention, the identically shaped sheet metal laminations 6 are rotated relative to one another, at least in the partial package, in such a way that several, in particular all, teeth 7 of the inner contour 6i of the respective sheet metal lamination 6 are each arranged partially overlapping with teeth 7 of adjacent sheet metal laminations 6, forming a tooth overlap 20 in each case.
[0030] The teeth have a tooth height H in the radial direction relative to the rotor axis 3, which, for example, lies in the range between 0.1 mm and 0.8 mm. The laminations 6, for example, have a sheet thickness in the range between 0.1 mm and 0.5 mm.
[0031] The structure of the inner circumference 5i of the rotor 2 shown in Fig. 2 can extend circumferentially over the entire inner circumference 5i without interruption. Alternatively, the structure of the inner circumference 5i of the rotor 2 can be interrupted at certain circumferential positions according to Figs. 3 to 5.
[0032] Fig.3 shows a two-dimensional view of the inner contour of the rotor according to Fig.1 according to a first embodiment.
[0033] According to the first exemplary embodiment, the inner contour 6i of the identically shaped sheet metal laminations 6 each has several sequences of a toothed section 10 and an intermediate groove 11. The intermediate grooves 11 are each arranged individually between two adjacent toothed sections 10 of the same sheet metal lamination 6. The toothed sections 10 each comprise a group of teeth 7, with a toothed groove 8 being formed between adjacent teeth 7 of the respective toothed section 10.
[0034] The intermediate grooves 11 of the sheet metal laminations 6 interrupt the toothed sections 10 in order to be able to arrange a weld seam 15 running in the axial direction in the intermediate grooves 11. The intermediate grooves 11 of the sheet metal laminations 6 are, for example, wider in the circumferential direction than the toothed grooves 8 of the toothed sections 10.
[0035] With respect to an individual one of the laminations 6, the number of toothed sections 10 and the number of intermediate grooves 11 each correspond, for example, to a number of rotor poles of the rotor 2.
[0036] The toothed sections 10 of the respective sheet metal lamination 6 each have the same number of teeth 7, except for one of the toothed sections 10.
[0037] The toothed sections 10 of the respective sheet metal lamination 6 have, for example, an odd number of teeth 7 in total.
[0038] Fig.4 shows a view of detail A of the inner contour according to Fig.3 according to a first embodiment.
[0039] The intermediate grooves 11 of the laminations 6 form a plurality of axial grooves 12 in the rotor core 5, extending in the axial direction relative to the rotor axis 3. At least one weld seam 15 is provided in at least one of the axial grooves 12 for connecting laminations 6 of the rotor core 5. The axial grooves 12 each have two uneven, in particular ribbed, groove flanks 12.1, which are formed by teeth 7 of the toothed sections 10 projecting to different extents into the respective axial groove 12.
[0040] A protruding welding nose 16 can be formed on each groove base 11.1 of the intermediate grooves 11 to form the weld seam 15. According to the first exemplary embodiment, the welding noses 16 are formed on the flat or level groove base of the intermediate grooves 11. The position or distance A of the welding noses 16 relative to the flanks 11.2 of the respective intermediate groove 11 varies in the intermediate grooves 11 of the same lamination 6 or in the group of intermediate grooves 11 of the same lamination 6 (Fig. 3). The laminations 6 are arranged such that the welding noses 16 of the same axial groove 12 are aligned with one another (Fig. 4).
[0041] Fig.5 shows a view of detail A of the inner contour according to Fig.3 according to a second embodiment.
[0042] According to the second embodiment, the groove base 11.1 of the intermediate grooves 11 each has a recess 17, which, viewed in the circumferential direction, is narrower than the respective intermediate groove 11 and is, for example, recessed relative to a tooth root diameter of the teeth 7. According to the second embodiment, the welding lugs 16 are provided within the recess 17 on the groove base 11.1.
Claims
Claims 1. Rotor (2) of an electric machine (1) with a rotor carrier (4), in particular a rotor shaft, rotatable about a rotor axis (3), and at least one rotor lamination stack (5) arranged on the rotor carrier (4), comprising a stack of laminations (6), wherein a press fit is provided between the rotor lamination stack (5) and the rotor carrier (4) for transmitting torque, wherein the laminations (6) each have an inner contour (6i) with teeth (7) on an inner circumference facing the rotor carrier (4) for forming the press fit, wherein at least one sub-stack of the rotor lamination stack (5) is formed from laminations (6) of identical shape, in particular identical shape, wherein the laminations (6) of identical shape are rotated relative to each other at least in the sub-stack by an angle of rotation, characterized in that the laminations (6) of identical shape are rotated relative to each other at least in the sub-stack such that several, in particular all,The teeth (7) of the inner contour (6i) of the respective sheet metal lamellae (6) are arranged to partially overlap teeth (7) of adjacent sheet metal lamellae (6).
2. Rotor according to claim 1, characterized in that the inner contour (6i) of the identical sheet metal lamellae (6) each has several sequences (9) of a toothed section (10) and an intermediate groove (11), wherein - the gear sections (10) each comprise a group of teeth (7), wherein a tooth groove (8) is formed between adjacent teeth (7) of the respective gear section (10), and - the intermediate slots (11) in the rotor lamination stack (5) form several axially extending axial slots (12), wherein at least one weld seam (15) for joining sheet metal lamellae (6) of the rotor lamination stack (5) is provided in at least one of the axial slots (12).
3. Rotor according to claim 2, characterized in that the axial grooves (12) each have two uneven, in particular ribbed, groove flanks (12.1) formed by teeth (7) of the toothing sections (10) projecting to different degrees into the respective axial groove (12).
4. Rotor according to one of claims 2 and 3, characterized in that the intermediate slots (11) are wider in the circumferential direction than the tooth slots (8) of the toothed sections (10).
5. Rotor according to one of claims 2 to 4, characterized in that a protruding weld nose (16) for forming the weld seam (15) is formed on a groove base (11.1) of the intermediate grooves (11), in particular in a recess (17) of the groove base (11.1).
6. Rotor according to claim 5, characterized in that the position of the weld lugs (16) relative to the flanks (11.2) of the respective intermediate groove (11) varies in the intermediate grooves (11) of the same sheet metal lamella (6) and that the sheet metal lamellae (6) are arranged such that the weld lugs (16) of the same axial groove (12) are aligned with each other.
7. Rotor according to one of claims 2 to 6, characterized in that, with respect to a single of the sheet metal lamellae (6), the number of toothed sections (10) and the number of intermediate slots (11) each correspond to a rotor pole number of the rotor (2).
8. Rotor according to one of claims 2 to 7, characterized in that the toothed sections (10) of the respective sheet metal lamella (6), with the exception of one of the toothed sections (10), each have the same number of teeth (7).
9. Rotor according to one of claims 2 to 8, characterized in that the toothed sections (10) of the respective sheet metal lamella (6) have a total odd number of teeth (7).
10. Electric machine with a rotor (2) according to one of the preceding claims.