Method and apparatus for manufacturing a stator lamination stack with opposing skewness

Abstract

Method for manufacturing a stator lamination stack (10) with opposing skew (11), having the following features: - Electrical tape is unwound from a coil (MC), - the unwound electrical steel strip is straightened and rolled, - the rolled electrical tape is punched and wound into a helix (12) and - the helix (12) is welded and pressed or otherwise stacked to form the stator lamination stack, characterized by the following features: - During stamping, the electrical tape is provided with recesses which, when wound up, form a groove in the stator lamination stack (10) with the desired inclination (11).

Description

[0001] The present invention relates to a method for manufacturing a stator lamination stack with opposing skew. The present invention further relates to a corresponding tool, a corresponding computer program, and a corresponding assembly line. State of the art

[0002] In electric motor technology, particularly in the manufacture of stators for electric machines, the efficient and cost-effective production of stator lamination stacks is of great importance. A key component of these stators are the stator lamination stacks, which consist of thin, stacked electrical steel laminations.

[0003] Numerous manufacturing processes exist in the art for producing a stacked stator lamination stack from electrical steel supplied on a coil. A particularly economical process, well-established in the automotive industry, is the production of a so-called "Slinky" stator lamination stack.

[0004] In this process, a narrow strip of stamped sheet metal is rolled up to form a stator lamination stack and then stacked. This manufacturing method is characterized by minimal sheet metal waste and a continuous stack build-up, which is why it is considered a cost-effective method for producing stator lamination stacks according to the state of the art.

[0005] From DE 102020208505 A1, FR 3092947 A1, DE 3587353 T2, US 4395815 A and US 7459826 B2 different stator lamination stacks for an electric machine are known, each of which is produced by this helical arrangement of an electrical tape with punched stator slots.

[0006] The manufacturing process of a Slinky stator lamination stack can be divided into several successive steps: First, the electrical steel strip, delivered on a coil, is rotatably mounted on the production line. This allows for continuous unwinding of the material throughout the entire production process.

[0007] In the next step, the unwound electrical tape is straightened. This process serves to eliminate any deformations or stresses in the material and to ensure a uniform thickness of the tape.

[0008] The electrical steel strip is then stamped. During this process, the grooves and other contours relevant to the stator geometry are cut into the material. The design and positioning of these stampings are crucial for the subsequent function and efficiency of the stator.

[0009] After the stamping process, the straight electrical steel strip is wound into a continuous helix. This spiral structure forms the basis for the subsequent stator lamination stack.

[0010] To achieve the desired stack height, the rolled-up helix is ​​cut at a defined point. This step makes it possible to obtain stator lamination stacks with different heights from the same manufacturing process.

[0011] Finally, the lamination stack is assembled. This is done, for example, through a welding process, which may be preceded or followed by a pressing process. Assembly can also be achieved through bonding or tongue-and-groove joints. This process firmly bonds the individual lamination layers together, resulting in a stable and compact stator lamination stack.

[0012] This established method for manufacturing stator lamination stacks offers the advantage of continuous and efficient production with minimal material waste. It has proven its worth in the industrial manufacturing of electric motors and is widely used in the automotive industry and other areas of electric motor production. Disclosure of the invention

[0013] One problem is that conventional methods for manufacturing slinky stator laminations are unable to achieve a counter-rotating skew of the slots. This counter-rotating skew is desirable, however, to reduce the axial length of the winding head as well as the circumferential length of the conductors within the winding head, thus significantly improving the efficiency and compactness of the electric machine. The precise arrangement and alignment of the slot segments in this case requires a high degree of precision and flexibility in the stamping process, which is difficult to achieve with existing methods.

[0014] In particular, the challenge lies in ensuring that the winding process of the electrical steel into a helix and the subsequent packaging of the sheet metal stack are designed in such a way that the opposing slant of the grooves is maintained.

[0015] These problems mean that conventional methods for manufacturing stator laminations with skew are only conditionally suitable for slinky stator laminations, thus limiting the efficiency and compactness of the electrical machines.

[0016] The described problem is solved by a method for manufacturing a stator lamination stack with opposing skew, a corresponding tool, a corresponding computer program and a corresponding assembly line according to the independent claims.

[0017] This approach offers the advantage of combining the well-known benefits of Slinky technology with those of skew stator laminations, resulting in improved magnetic interaction between the stator and rotor. The skew reduces torque pulsations, directly contributing to lower noise emissions. This represents a significant advancement that improves the quality of life for end users and facilitates compliance with increasingly stringent environmental and noise regulations.

[0018] Further advantageous embodiments of the invention are specified in the dependent patent claims. Brief description of the drawings Fig. Figure 1 shows the construction of a slanted stator. Fig. Figure 2 shows the helix of a Slinky stator lamination stack. Fig. Figure 3 shows the winding process as part of the manufacturing process of a Slinky stator lamination stack. Fig. Figure 4 shows a cross-section of the helix of a Slinky stator. Fig. 5 to Fig. Figure 7 shows the helix in three further cross-sectional planes. Fig. Figure 8 shows the phase and counter-rotating groove pattern of the helix. Embodiments of the invention

[0019] Fig. Figure 1 illustrates the basic structure of a skewed stator (10) as used in electric motors. The skewing (11) of the stator lamination stack is clearly visible, which has a decisive influence on the magnetic properties and the noise generation of the motor.

[0020] Fig. Figure 2 shows the characteristic helical structure (12) of a “Slinky stator lamination stack”. This design, reminiscent of a spiral spring, forms the basis for the innovative manufacturing process.

[0021] The multi-stage manufacturing process of such a "slinky stator lamination stack" begins with straightening the electrical steel strip used as the starting material, which is delivered beforehand as a coil (MC). Before being wound into a coil, the material is rolled to the desired thickness. In the next step, punching, the slots and other relevant geometries of the stator are cut into the electrical steel strip. Here, and this is a key aspect of the process, recesses are deliberately placed in the material, which later in the process enable the desired skew of the stator lamination stack. During the winding process (24 - Fig. 4) In the manufacturing process, the stamped electrical steel strip is continuously formed into a helix (12). The previously introduced recesses cause a displacement of the individual turns of the helix (12), resulting in the characteristic skewing of the stator lamination stack.

[0022] Fig. Figure 4 illustrates this relationship using a cross-section through the helix (12) of the “Slinky stator”. The displacement of the individual turns caused by the cutouts in the material, which determines the inclination (11 - ), is clearly visible. Fig. 1) of the stator lamination stack. Fig. Figures 5 to 7 show the helix in three further cross-sectional planes, thus illustrating the spatial form of the oblique angle.

[0023] The resulting groove profile is in Fig. Figure 8 illustrates which phases (U, V, W) are emphasized in detail. This targeted control of the skew allows for the optimization of the stator's magnetic properties and thus the motor's performance.

[0024] After the helix (12) is wound up, the "slinky stator lamination stack" is joined into a solid stack by welding and / or pressing processes, thus creating the final shape of the stator. However, the stacking can also be achieved via an adhesive bonding process or tongue-and-groove connections. Reference symbol list 10 Stator lamination stack 11. Inclination 12 Helix MC Coil U, V, W phases QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102020208505 A1

[0005] FR 3092947 A1

[0005] DE 3587353 T2

[0005] US 4395815 A

[0005] US 7459826 B2

[0005]

Claims

[1] Method for manufacturing a stator lamination stack (10) with opposing skew (11), comprising the following features: - Electrical tape is unwound from a coil (MC), - the unwound electrical steel strip is straightened and rolled, - the directed electrical tape is punched and wound into a helix (12) and - the helix (12) is welded and pressed into the stator lamination stack or otherwise packaged, characterized by the following characteristic: - During stamping, the electrical tape is provided with recesses which, when wound up, form a groove in the stator lamination stack (10) with the desired inclination (11). [2] Method according to claim 1, characterized by one of the following characteristics: - the punching is carried out in such a way that the cutouts complement each other radially to the groove when winding or - The stamping process is carried out in such a way that a bridge remains in the electrical strip between the cutouts. [3] Method according to claim 1 or 2, characterized by the following characteristics: - the cutouts are formed by different dies during the stamping process and - the electrical strip is advanced during punching at such a variable speed that the recesses have a parallel displacement to each other which corresponds to the chamfer (11). [4] Method according to any one of claims 1 to 3, characterized by the following characteristic: - During the stamping process, the electrical tape is given additional contours. [5] Method according to any one of claims 1 to 4, characterized by the following characteristic: - after coiling, the helix (12) is split in such a way that the stator lamination stack (10) has a desired height after pressing. [6] Method according to any one of claims 1 to 5, characterized by one of the following characteristics: - the welding takes place before pressing or - Welding takes place after pressing. [7] Method according to any one of claims 1 to 6, characterized by the following characteristics: - the process is carried out in line production and - the coil (MC) is mounted so that it can be rotated for unwinding. [8] Tool, characterized by the following characteristics: - the tool has several punches for punching the recesses and - the tool is designed to carry out a method according to one of claims 1 to 7. [9] Computer program configured to control a tool according to claim 8 such that it performs according to any one of claims 1 to 7. [10] Assembly line with a tool according to claim 8.

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