Low-loss amorphous stator core based on laser scoring and preparation method thereof

Abstract

The application provides a low-loss amorphous stator core based on laser marking and a preparation method thereof. The stator core is formed by laminating and bonding a plurality of stator punching sheets. The stator punching sheets are formed by stamping a composite strip. The composite strip comprises a middle layer group and a surface layer group. The middle layer group comprises at least one first amorphous alloy strip. The surface layer group comprises a second amorphous alloy strip arranged on the surface of the middle layer group. The surface of the first amorphous alloy strip is provided with a plurality of laser marking lines arranged at intervals with a spacing D1. The surface of the second amorphous alloy strip is not provided with laser marking lines or is provided with a plurality of laser marking lines arranged at intervals with a spacing D2. The width of the laser marking lines is 5-40 microns. 1 mm≤D1≤30 mm, and D2≥50 mm. According to the differential interlayer marking design, the strip arranged on the surface is not subjected to laser marking or is subjected to extremely shallow and sparse marking, thereby serving as an “armor layer” to bear the stamping shearing force, protect the internal marking strip, and bear the magnetic domain refinement function.

Description

Technical Field

[0001] This invention relates to the field of motor manufacturing technology, specifically to a low-loss amorphous stator core based on laser marking and its preparation method. Background Technology

[0002] Amorphous alloys, as a novel type of soft magnetic material, exhibit excellent soft magnetic properties such as high permeability, low coercivity, high resistivity, and extremely low iron loss due to their unique atomic arrangement structure with long-range disorder and short-range order. Especially under medium- and high-frequency operating conditions, the iron loss of amorphous alloys is only 1 / 8 to 1 / 10 that of traditional grain-oriented silicon steel, and this advantage becomes more pronounced at higher frequencies, making them promising for applications in high-speed motors, new energy vehicle drive motors, and high-speed spindle motors. Replacing traditional silicon steel with amorphous alloys in motor stator cores can significantly reduce iron loss, increase power density, and improve operating efficiency. Studies have shown that motors using amorphous alloy stator cores can achieve operating efficiencies of over 95%, with some reaching as high as 98%. In scenarios requiring high-frequency operation, such as electric vehicles, amorphous motors can maintain high efficiency within a speed range of 2000–6000 r / min, effectively solving the problem of dramatically increased iron loss in permanent magnet motors at high frequencies.

[0003] In existing technologies, the manufacturing of amorphous alloy stator cores mainly involves the following processes: 1. Punching or shearing amorphous strips to form amorphous single sheets with a predetermined shape, coating the surface of the single sheets with an insulating coating, then stacking them to form amorphous blocks, followed by annealing heat treatment, impregnation treatment, and curing treatment, and finally shaping them into the required stator core shape by wire cutting or laser cutting. 2. Using a method of first winding and forming, then annealing, and then cutting, for example, winding amorphous strips into rings according to the stator yoke and tooth parts respectively, annealing the wound parts, then impregnating and curing them, and finally cutting them according to the number of tooth slots. 3. Using multi-layer single-layer amorphous alloy strips, stamping them, and then bonding and stacking them to form the core.

[0004] To address the challenge of directly stamping amorphous ribbons due to their thinness and low stiffness, multilayer composite ribbon technology has gradually become a focus of industry attention. A typical process involves continuously stacking multiple single-layer amorphous alloy ribbons to form a multilayer composite ribbon. Adhesive is applied between adjacent amorphous alloy ribbons, and the adhesive is preheated to improve its fluidity and then pressed together. After curing and cooling, the resulting multilayer amorphous alloy composite material is obtained.

[0005] Laser marking technology is an effective method for refining magnetic domains and reducing iron loss by introducing regularly distributed markings on the surface of soft magnetic materials using a laser beam. In recent years, laser marking technology has been gradually introduced into the field of amorphous alloy strips. Existing research shows that laser marking can refine the magnetic domain width of amorphous strips to 1 / 10 to 1 / 3 of the original strip width, and combined with annealing processes, can reduce losses by 30% to 50%.

[0006] However, the existing technology for applying laser marking to the manufacturing process of amorphous alloy stator cores has the following problems: it only focuses on the marking morphology of a single layer of strip to reduce losses, without considering the differentiated impact of marking on each layer of multi-layer composite strip on subsequent stamping processes. When all layers of composite strip are marked with the same parameters, the overlap of markings in the thickness direction will aggravate the accumulation of interlayer stress when facing the stamping process, and the stress concentration in the outer marking area will lead to cross-sectional tearing during stamping. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings and deficiencies of the existing technology and to provide a low-loss amorphous stator core based on laser marking and its preparation method.

[0008] The technical solution adopted in this invention is as follows: The first aspect of this invention provides a low-loss amorphous stator core based on laser marking, which is formed by stacking and bonding a plurality of stator laminations, wherein the stator laminations are stamped from composite strip. The composite strip comprises a parallel intermediate layer group and a surface layer group. The intermediate layer group comprises at least one first amorphous alloy strip, and the surface layer group comprises a second amorphous alloy strip located on the surface of the intermediate layer group. The surface of the first amorphous alloy strip is provided with a plurality of laser marking lines arranged at intervals D1, and the surface of the second amorphous alloy strip is either free of laser marking lines or has a plurality of laser marking lines arranged at intervals D2. The line width of the laser etched lines is 5μm-40μm, 1mm≤D1≤30mm, and D2≥50mm.

[0009] Preferably, two adjacent laser marking lines on the surfaces of two adjacent layers of the first amorphous alloy strip do not completely overlap in the thickness direction.

[0010] Preferably, the laser marking lines on the surfaces of two adjacent layers of the first amorphous alloy strip form an included angle α, where 15°≤α≤90°.

[0011] Preferably, the laser marking lines on the surfaces of two adjacent layers of the first amorphous alloy strip are perpendicular.

[0012] Preferably, the laser marking line is a smooth wavy marking formed by connecting several continuous pulse pits, and the overlap of the pulse pits ε≥0.5.

[0013] Preferably, the distance between the end of the laser-etched line and the edge of the amorphous ribbon it is located is ≥1mm.

[0014] This setting effectively protects the structural integrity of the strip edge, reduces the risk of edge cracking, and ensures that the scoring lines are distributed within the effective area of ​​the strip, guaranteeing the coverage of magnetic domain refinement and uniformly reducing the overall iron loss of the core.

[0015] Preferably, it is obtained by stacking and bonding several stator laminations, followed by baking and curing, and then annealing with a gradient magnetic field. The gradient magnetic field annealing includes a magnetic field induction stage in which the temperature is maintained at 300℃~380℃ under a rotating magnetic field.

[0016] A second aspect of the present invention provides a method for preparing a low-loss amorphous stator core based on laser marking, comprising the following steps: (1) Laser scribing is performed on the amorphous alloy strips respectively. The laser scribing lines on the surface of the first amorphous alloy strip used to form the intermediate layer group are arranged at intervals of D1. The laser scribing lines on the surface of the second amorphous alloy strip used to form the surface layer group are not laser scribing or are arranged at intervals of D2. (2) The amorphous ribbons after laser marking are stacked in sequence, and an adhesive is coated between adjacent layers. The composite ribbon is then heated and pressed to cure. (3) The composite strip is stamped to obtain stator laminations; (4) The stator laminations are glued and stacked together to form a core stack; (5) The iron core stack is baked and cured and subjected to gradient magnetic field annealing treatment, wherein the gradient magnetic field annealing includes a magnetic field induction stage in which the core is kept at 300℃~380℃ under a rotating magnetic field.

[0017] Preferably, in step (5), the gradient magnetic field annealing includes the following stages: (5-1) Preheating stage: Heat to 200℃ at a heating rate of 10-20℃ / min without applying a magnetic field; (5-2) Stress relaxation stage: Hold at a temperature of 200-300℃ for 10-30 minutes without applying a magnetic field; (5-3) Magnetic field induction stage: Keep warm in the temperature range of 300-380℃ for 20-40 min, apply a rotating magnetic field with a magnetic field strength of 70-100kA / m and a rotation speed of 2-5rpm; (5-4) Cooling and shaping stage: Cool to room temperature at a cooling rate of 3-5℃ / min, and remove the rotating magnetic field after maintaining it at 200℃ during the cooling process.

[0018] Preferably, in step (5), when D1≤5mm, the annealing temperature of the magnetic field induction stage is 300-340℃; when D1>5mm, the annealing temperature of the magnetic field induction stage is 350-380℃.

[0019] Preferably, in step (1), the laser marking parameters are: laser frequency 10-100 kHz, laser scanning rate 1000-6000 mm / s, and laser energy density 1-10 J / m.

[0020] The beneficial effects of this invention are as follows: 1. This invention uses a differentiated interlayer scoring design. The surface strip is not laser-scored or only has very shallow and sparse scoring applied, which acts as an "armor layer" to bear the stamping shear force and protect the internal scoring strip. The internal strip is heavily scored to perform the magnetic domain refinement function.

[0021] 2. The laser-etched lines on the surfaces of two adjacent layers of the first amorphous alloy strip form an angle, creating a grid-like interlacing of the intermediate layers in a three-dimensional plane. This enhances the toughness of the composite strip and allows for the formation of more uniform magnetic domains during the annealing stage. This design effectively solves the problem of cross-sectional tearing caused by outer layer etching during stamping. The stamping yield is increased by 10% to 15% compared to the full-layer uniform etching scheme, and decoupling of stamping toughness and magnetic properties is achieved without adding extra processes.

[0022] 3. Stator cores after lamination typically require magnetic field annealing to optimize magnetic properties. Traditional longitudinal magnetic field annealing is only suitable for single-layer or thin-layer cores. When the core lamination height is large, the magnetic field creates shielding within the core, leading to uneven magnetic domain orientation in the internal layers and a relative deviation in the overall core performance. This invention combines gradient magnetic field annealing with a rotating magnetic field. During the magnetic field induction stage, the magnetic field direction rotates continuously within the core plane, integrating the advantages of transverse and longitudinal magnetic field treatments. This effectively overcomes the magnetic shielding effect of thick-layer cores, ensuring uniform magnetic domain orientation in each lamination layer. The uniformity of magnetic properties is significantly better than that of traditional single-direction magnetic field annealing.

[0023] 4. The amorphous alloy stator core obtained by this invention has a loss as low as 4.9-5.3W / kg under the condition of 1kHz / 0.7T, which is about 21% lower than that of amorphous alloy stators that only undergo ordinary heat treatment.

[0024] 5. The process of this invention is simple, has low processing cost, high efficiency, and can be scaled up for production. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0026] Figure 1This is a schematic diagram of the equipment used in the laser marking step in various embodiments and comparative examples of the present invention; Figure 2 This is a schematic diagram of the composite strip structure obtained in Embodiment 1 of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings.

[0028] To address the problems in related technologies, this application provides a low-loss amorphous stator core based on laser marking, which is formed by stacking and bonding several stator laminations. The stator laminations are formed by stamping composite strips. The composite strips include a parallel intermediate layer group and a surface layer group. The intermediate layer group includes at least one first amorphous alloy strip, and the surface layer group includes a second amorphous alloy strip located on the surface of the intermediate layer group. The surface of the first amorphous alloy strip is provided with several laser marking lines arranged at intervals of D1. The surface of the second amorphous alloy strip is either not provided with laser marking lines or has several laser marking lines arranged at intervals of D2. The line width of the laser marking lines is 5μm-40μm, 1mm≤D1≤30mm, and D2≥50mm.

[0029] Stator laminations are the basic units constituting the stator core. They are assembled into a complete stator core through lamination and bonding. Conventional insulating bonding processes used in existing technologies can be employed during lamination to ensure insulation and strong connection between laminations, preventing interlayer eddy currents and further reducing iron loss. The composite strip is the forming substrate for the stator laminations. It features a two-layer structure design consisting of an intermediate layer and a surface layer. The core design element is the differentiated setting of laser-etched markings, balancing iron loss reduction with stamping performance. The intermediate layer, as the core functional layer of the composite strip, plays a major role in optimizing magnetic properties. Therefore, it uses a first amorphous alloy strip with laser-etched lines to refine magnetic domains and reduce iron loss. The surface layer, as the protective and support layer of the composite strip, primarily enhances the overall rigidity of the composite strip, facilitating subsequent stamping. Therefore, it can be selected to have no markings or to have markings with larger spacing to reduce stress concentration during stamping. The linewidth and spacing parameters of the laser marking lines are limited by comprehensively considering the magnetic domain refinement effect and the integrity of the strip structure. If the linewidth is too narrow, the magnetic domain refinement effect will be insignificant; if it is too wide, it will damage the strip's structural strength. The spacing range of D1 can achieve effective magnetic domain refinement, while D2 ≥ 50mm can avoid the impact of surface markings on stamping performance. Laser marking can be achieved using... Figure 1The laser marking equipment shown is used for processing to ensure marking accuracy and consistency. This technical solution effectively solves the problem of stamping section tearing caused by marking in existing technologies by adopting differentiated laser marking designs for different layers of composite strip. At the same time, iron loss is reduced by marking the intermediate layer, taking into account both the magnetic properties and processing performance of the stator core. This allows the prepared stator core to maintain excellent low-loss characteristics under medium and high frequency operating conditions, making it suitable for applications such as high-speed motors and new energy vehicle drive motors.

[0030] Optionally, in some embodiments, the laser marking lines on the surfaces of two adjacent layers of the first amorphous alloy strip form an angle α, where 15°≤α≤90°. Setting an angle between the laser marking lines on the surfaces of two adjacent layers of the first amorphous alloy strip essentially changes the orientation of the markings in each layer, causing differences in the magnetic domain refinement direction of each amorphous strip layer. This avoids overlap of multiple markings in the thickness direction, further alleviating interlayer stress accumulation. Simultaneously, it optimizes the overall magnetic anisotropy of the core, improving the core's permeability and magnetic field response characteristics. In specific implementation, during the laser marking process, the placement angle of the amorphous alloy strip layers or the processing angle of the laser marking equipment can be adjusted to create a preset angle between the marking lines of two adjacent layers of the first amorphous alloy strip. For example, the laser marking direction can be set to process one set of strip along the strip length direction, then the laser marking direction can be adjusted to form an angle α with the strip length direction, and another set of strip can be processed. Then, the strips from the two sets can be stacked to ensure that the laser marking directions of adjacent strip layers are different. This configuration not only reduces stress concentration during stamping and prevents cross-sectional tearing, but also makes the magnetic properties of the iron core more uniform in different directions, adapting to the magnetic field requirements of the motor in different directions.

[0031] Optionally, in some embodiments, the laser marking lines on the surfaces of two adjacent layers of the first amorphous alloy strip are perpendicular. This perpendicular arrangement of the marking lines on two adjacent layers of the first amorphous alloy strip is a preferred method for the aforementioned angle setting. It minimizes the overlap of markings between adjacent layers, reduces interlayer stress accumulation, and ensures that the magnetic domain refinement directions of the two strip layers are perpendicular to each other, further optimizing the magnetic anisotropy of the core. This allows the core to achieve excellent permeability and low iron loss characteristics in both perpendicular directions. Furthermore, this angle setting facilitates the laser marking operation; the laser marking direction can be set to process the strip along its length and width, respectively. This perpendicular arrangement allows for uniform stress distribution along the thickness direction during stamping, preventing cross-sectional tearing caused by localized stress concentration. It also improves the core's adaptability to complex magnetic fields, making it particularly suitable for applications requiring high magnetic uniformity, such as high-speed motors.

[0032] Optionally, in some embodiments, the laser-etched line is a smooth, wavy etched line formed by connecting several continuous pulsed pits, with a pulsed pit overlap ε≥0.5. The core purpose of using a smooth, wavy structure formed by connecting continuous pulsed pits in the laser-etched line is to reduce damage to the amorphous ribbon surface while achieving magnetic domain refinement, avoiding stress concentration caused by sharp etchers. Simultaneously, the smooth, wavy structure reduces adhesive buildup during subsequent lamination, ensuring uniform interlayer bonding. A pulsed pit overlap ε≥0.5 means that there is a certain degree of overlap between adjacent pulsed pits, allowing the etched line to form a continuous, smooth structure, avoiding broken etched segments, thereby ensuring the continuity of magnetic domain refinement and ensuring stable iron loss reduction. In practice, the size, spacing, and overlap of the pulse pits can be controlled by adjusting the pulse parameters of the laser marking equipment. For example, by using parameters such as a laser frequency of 50kHz and a scanning rate of 3000mm / s, the diameter and spacing of the pulse pits can be matched to ensure an overlap of ≥0.5. At the same time, by adjusting the laser energy density, the pit depth can be made moderate to form a smooth wavy marking.

[0033] Optionally, in some embodiments, the distance between the end of the laser-etched line and the edge of the amorphous ribbon is ≥1mm. Limiting the distance between the end of the laser-etched line and the edge of the amorphous ribbon to ≥1mm is primarily to prevent the etched line from extending to the edge of the ribbon, causing stress concentration at the edge and potentially leading to edge cracking during subsequent lamination and stamping processes. It also prevents edge etchers from affecting the sealing of interlayer bonding, preventing gaps between layers from increasing eddy currents and affecting the magnetic properties of the core.

[0034] Optionally, in some embodiments, it is obtained by laminating and bonding several stator laminations, followed by baking curing and gradient magnetic field annealing. The gradient magnetic field annealing includes a magnetic field induction stage under a rotating magnetic field at a temperature of 300℃~380℃. Baking curing after lamination and bonding of the stator laminations is to ensure the adhesive between the laminations is fully cured, improving the structural strength and stability of the core stack and preventing interlayer separation during subsequent annealing. Baking curing can employ conventional heating curing processes in existing technologies, controlling the heating temperature and time to ensure complete adhesive curing. Gradient magnetic field annealing is designed to address the problem of uneven magnetic domain orientation within the core caused by traditional longitudinal magnetic field annealing in existing technologies. Its core principle is to achieve uniform orientation of magnetic domains in each layer of the core strip through the combination of gradient temperature and rotating magnetic field, while simultaneously repairing stress relaxation caused by laser marking during subsequent processing and maintaining the domain refinement effect of the markings. The magnetic field induction stage, which involves holding the temperature at 300℃~380℃ under a rotating magnetic field, is the core step of gradient magnetic field annealing. This temperature range falls within the magnetic domain optimization temperature range of amorphous alloys, enabling the reorientation of magnetic domains without altering the atomic arrangement structure of the amorphous alloy, thus preventing magnetic degradation. The rotating magnetic field ensures that the magnetic field acts uniformly on all areas of the iron core, including the internal layers, effectively solving the magnetic field shielding problem, ensuring consistent magnetic domain orientation in each layer, and improving the overall magnetic performance of the iron core.

[0035] This embodiment also includes a method for preparing a low-loss amorphous stator core based on laser marking, comprising the following steps: (1) Laser scribing is performed on the amorphous alloy strips respectively. The laser scribing lines on the surface of the first amorphous alloy strip used to form the intermediate layer group are arranged at intervals of D1. The laser scribing lines on the surface of the second amorphous alloy strip used to form the surface layer group are not laser scribing or are arranged at intervals of D2. (2) The amorphous ribbons after laser marking are stacked in sequence, and an adhesive is coated between adjacent layers. The composite ribbon is then heated and pressed to cure. (3) The composite strip is stamped to obtain stator laminations; (4) The stator laminations are glued and stacked together to form a core stack; (5) The iron core stack is baked and cured and subjected to gradient magnetic field annealing treatment, wherein the gradient magnetic field annealing includes a magnetic field induction stage in which the core is kept at 300℃~380℃ under a rotating magnetic field.

[0036] Optionally, in some embodiments, step (5) of the gradient magnetic field annealing includes the following stages: (5-1) Preheating stage: Heat to 200℃ at a heating rate of 10-20℃ / min without applying a magnetic field; (5-2) Stress relaxation stage: Hold at a temperature of 200-300℃ for 10-30 minutes without applying a magnetic field; (5-3) Magnetic field induction stage: Keep warm in the temperature range of 300-380℃ for 20-40 min, apply a rotating magnetic field with a magnetic field strength of 70-100kA / m and a rotation speed of 2-5rpm; (5-4) Cooling and shaping stage: Cool to room temperature at a cooling rate of 3-5℃ / min, and remove the rotating magnetic field after maintaining it at 200℃ during the cooling process.

[0037] The four stages of gradient magnetic field annealing proceed sequentially to form a complete annealing process. Its core is to optimize the magnetic properties of the iron core and maintain the scoring effect through gradual heating, stress relaxation, magnetic field induction, and slow cooling, while avoiding the generation of new stress during the annealing process. The preheating stage involves heating to 200℃ at a rate of 10-20℃ / min without applying a magnetic field. This is primarily to ensure a uniform temperature increase in the core stack, avoid thermal stress caused by rapid heating, and protect the structural integrity of the core. The stress relaxation stage involves holding at 200-300℃ without applying a magnetic field. This releases the mechanical stress generated during the stacking and stamping process, laying the foundation for subsequent magnetic domain orientation and reducing the impact of stress on magnetic properties. The magnetic field induction stage, a core step, involves holding at 300-380℃ and applying a rotating magnetic field with specific parameters. This allows the magnetic domains to orient uniformly under the influence of the magnetic field, while simultaneously repairing the stress relaxation caused by laser markings and maintaining the domain refinement effect. The cooling and shaping stage involves slow cooling at a rate of 10-20℃, maintaining a rotating magnetic field until 200℃. This ensures the well-oriented magnetic domains are stabilized and shaped, preventing rapid cooling from causing domain orientation disorder and ensuring stable annealing results.

[0038] Optionally, in some embodiments, in step (5), when D1 ≤ 5 mm, the annealing temperature of the magnetic field induction stage is 300-340℃; when D1 > 5 mm, the annealing temperature of the magnetic field induction stage is 350-380℃. This setting is based on the notch spacing D1 of the first amorphous alloy strip, specifically adjusting the annealing temperature of the magnetic field induction stage. The core is to achieve a precise match between the notch effect and the annealing effect, ensuring that the magnetic domain refinement effect is fully maintained and optimized. When D1≤5mm, the groove spacing is relatively dense, and the magnetic domain refinement is relatively high. If a higher annealing temperature is used at this time, it may cause the beneficial stress field introduced by the groove to relax excessively, which will destroy the magnetic domain refinement effect. Therefore, a lower annealing temperature (300-340℃) is selected to optimize the magnetic domain orientation and avoid the degradation of the groove effect. When D1>5mm, the groove spacing is relatively sparse, and the magnetic domain refinement is relatively low. A higher annealing temperature (350-380℃) is required to better promote the magnetic domain orientation, improve the magnetic properties, and at the same time make up for the insufficient iron loss reduction effect caused by the sparse groove spacing.

[0039] Optionally, in some embodiments, the laser marking parameters in step (1) are: laser frequency 10-100 kHz, laser scanning rate 1000-6000 mm / s, and laser energy density 1-10 J / m. Specifying the exact parameters for laser marking is to ensure the quality and consistency of the laser marking lines, achieve a balance between the magnetic domain refinement effect and the integrity of the strip structure, and avoid situations where improper parameters lead to excessively deep or shallow markings or uneven line widths, affecting the magnetic properties and processing performance of the core. The laser frequency range of 10-100kHz can be flexibly adjusted according to the required line width of the scribe line. High-frequency lasers can obtain finer scribe lines, while low-frequency lasers can improve scribe efficiency. The laser scanning rate of 1000-6000mm / s can control the depth and continuity of the scribe line. If the scanning rate is too fast, the scribe line will be too shallow and the magnetic domain refinement effect will be insignificant. If it is too slow, the scribe line will be too deep and damage the strip structure. The laser energy density of 1-10J / m can be matched with amorphous strips of different thicknesses to ensure that the scribe line depth is moderate, which can refine the magnetic domains without causing the strip to break.

[0040] Example 1 This embodiment provides a low-loss amorphous stator core based on laser marking and its preparation method, which includes the following steps: Step 1: Preparation of Amorphous Ribbon Commercially available FeSiB amorphous alloy strip (grade 1K101) was selected, with a width of 230 mm and a thickness of 25 μm ± 2 μm. The strip has a saturation magnetic induction intensity Bs of 1.56 T, a Curie temperature Tc of 410℃, and a crystallization temperature Tx of 510℃. The strip has a smooth, fish-scale pattern with clean, burr-free edges. Before use, the strip was visually inspected, and sections with obvious scratches, creases, or rust spots were removed. The strip was then cut to 230 mm widths. A single sheet of 230.

[0041] Step 2: Differentiated laser marking of single-layer strip like Figure 1 As shown, a pulsed laser continuous marking device is used for laser marking. This device includes a laser marking machine and a leveling device for fixing the amorphous sheet. The laser marking machine includes a focusing device and several fiber pulsed lasers (wavelength 1064nm, maximum power 30W) with adjustable spacing. The device also includes a pressure adsorption assembly. A semi-sealed container with tiny, densely packed holes is placed on the platform, connected to a vacuum device to create negative pressure, tightly adsorbing the amorphous ribbon onto the platform. This prevents the amorphous sheet from bending due to heat during marking, which could lead to uneven marking later.

[0042] The parameters for each scoring layer are as follows: Surface layers (layer 1 and layer 5): No laser etching is performed.

[0043] Inner layers (layers 2 and 4): The scoring direction is along the strip width direction (perpendicular to the strip length direction). Scoring parameters: score spacing D = 2 mm, score line length L to strip width S ratio L / S = 0.9, i.e., the distance between the end of the score line and both sides of the strip edge is 1.5 mm. Laser energy density is 4 J / m, laser frequency is 50 kHz, and score width is 20 μm.

[0044] Core layer (3rd layer): The scoring direction is along the length of the strip. Scoring parameters: scoring spacing D = 2mm, scoring line length direction is along the strip length direction, and the distance between both ends of the scoring line and the strip edge along the strip length direction is 1.5mm. Laser energy density is 4J / m, laser frequency is 50kHz, and scoring width is 20μm.

[0045] The aforementioned marking morphology consists of a smooth, wavy structure formed by closely connected pulse pits, with an overlap of ε = 0.6~0.7 between adjacent pulse pits. Laser marking is performed under an argon protective atmosphere to prevent oxidation of the strip surface.

[0046] The five-layer amorphous alloy strip after laser marking is stacked in the following order: Layer 1 (surface layer, no marking) → Layer 2 (inner layer, transverse marking) → Layer 3 (core layer, longitudinal marking) → Layer 4 (inner layer, transverse marking) → Layer 5 (surface layer, no marking).

[0047] Step 3: Preparation of multilayer composite strip A silicone-modified epoxy resin adhesive is uniformly coated between two adjacent strips. In this embodiment, the adhesive is applied by brushing the stencil with adhesive.

[0048] The stacked five-layer strip is fed into a hot press for heating and pressure curing. The curing process is as follows: the temperature is increased to 200℃ at a rate of 5℃ / min, a pressure of 0.8MPa is applied, and the temperature is held for 10 minutes. After curing, the strip is slowly cooled in the furnace to below 80℃ at a cooling rate of 3℃ / min, and then removed to obtain a five-layer composite strip, the structure of which is as follows. Figure 2 As shown.

[0049] The resulting composite strip has a total thickness of 0.13 mm and a width of 230 mm.

[0050] Step 4: Stamping The composite strip obtained in step three is fed into the stamping production line. The stamping die is made of tungsten steel, and the stator inner and outer circles, tooth grooves, and positioning grooves are formed simultaneously in one stamping operation to obtain stator laminations. The stator laminations have an outer diameter of 180 mm, an inner diameter of 126 mm, and 48 tooth grooves.

[0051] Step 5: Stamping, Glue Application, and Stacking The stamped stator laminations are then coated with adhesive on one side. The same silicone-modified epoxy resin adhesive used in step three is applied in a scattered pattern through a stencil, with the adhesive layer thickness controlled between 1 μm and 2 μm.

[0052] Step Six: Stacking and Molding After applying the adhesive, the stator laminations are placed in the tooling and aligned and stacked according to the corresponding positioning slots. In this embodiment, the stacking height is 20mm. After the laminations are stacked, they are pressed by applying pressure through bolts and pressure plates. During the stacking process, the coaxiality and perpendicularity of the laminations are ensured by the positioning mandrel and the outer circle positioning fixture.

[0053] Step 7: Firing and Curing The stacked iron core blocks were placed in an oven for curing. The curing process was as follows: the temperature was increased to 170℃ at a rate of 3℃ / min and held for 1 hour; after curing, the core blocks were slowly cooled to room temperature in the oven. The curing iron core blocks had a stacking factor of 0.92, with strong interlayer bonding and no delamination.

[0054] Step 8: Gradient magnetic field annealing The cured iron core stacks are placed in a rotating magnetic field annealing furnace for gradient magnetic field annealing. The annealing process consists of the following four stages: Preheating stage: The temperature is rapidly increased from room temperature to 200°C at a rate of 15°C / min, without applying a magnetic field.

[0055] Stress relaxation stage: The temperature is increased at a rate of 5℃ / min within the range of 200℃ to 300℃, and then held at 300℃ for 25 minutes without applying a magnetic field. This stage is used to release the macroscopic mechanical stress introduced during the stamping, lamination, and curing processes.

[0056] Magnetic field induction stage: The temperature was increased from 300℃ to 320℃ at a rate of 3℃ / min. A rotating magnetic field with a strength of 80kA / m and a rotation speed of 3rpm was applied when the temperature reached 320℃. The temperature was held at 320℃ for 30min to allow the magnetic domains to align regularly along the groove direction under the influence of the rotating magnetic field.

[0057] Cooling and setting stage: After the heat preservation is completed, the material is slowly cooled to room temperature at a cooling rate of 3℃ / min. During the cooling process, the rotating magnetic field is maintained up to 200℃, after which the magnetic field is removed and cooling continues.

[0058] Step Nine: Sandblasting and rust prevention treatment and finished product inspection After annealing, the iron core stack is subjected to surface sandblasting to remove the surface oxide layer and burrs. Then, a thin layer of water-based rust inhibitor is sprayed on the inner and outer circles and end faces of the iron core.

[0059] Example 2 This embodiment provides a low-loss amorphous stator core based on laser marking and its preparation method. The difference between the preparation method of this embodiment and that of Embodiment 1 is as follows: In step two, the scribe spacing D = 6mm for the inner layers (layer 2 and layer 4) and the scribe spacing D = 6mm for the core layer (layer 3); In step eight, since the spacing between the indentations of the inner layer and the core layer is 6mm, the annealing temperature for the magnetic field induction stage is 360℃ and the holding time is 30min.

[0060] Example 3 This embodiment provides a low-loss amorphous stator core based on laser marking and its preparation method. The difference between the preparation method of this embodiment and that of Embodiment 1 is as follows: The surface layers (layers 1 and 5) undergo laser scribing, with the scribing direction along the width of the strip. Scribing parameters: scribing spacing D = 50 mm, scribing line length L to strip width S ratio L / S = 0.9, meaning the distance between the end of the scribing line and both edges of the strip is 1.5 mm. The laser energy density is 4 J / m, the laser frequency is 50 kHz, and the scribing width is 20 μm.

[0061] Example 4 This embodiment provides a low-loss amorphous stator core based on laser marking and its preparation method. The difference between the preparation method of this embodiment and that of Embodiment 1 is as follows: The surface layers (layers 1 and 5) undergo laser scribing, with the scribing lines running along the length of the strip. Scribing parameters: scribing spacing D = 50 mm, scribing line length L to strip width S ratio L / S = 0.9, meaning the distance between the end of the scribing line and both edges of the strip is 1.5 mm. The laser energy density is 4 J / m, the laser frequency is 50 kHz, and the scribing width is 20 μm.

[0062] Example 5 This embodiment provides a low-loss amorphous stator core based on laser marking and its preparation method. The difference between the preparation method of this embodiment and that of Embodiment 1 is as follows: The surface layers (layers 1 and 5) undergo laser scribing, with the scribing direction along the width of the strip. Scribing parameters: scribing spacing D = 75 mm, scribing line length L to strip width S ratio L / S = 0.9, meaning the distance between the end of the scribing line and both edges of the strip is 1.5 mm. Laser energy density is 4 J / m, laser frequency is 50 kHz, and scribing width is 20 μm.

[0063] Comparative Example 1 This comparative example provides an amorphous stator core based on laser etching and its preparation method. The difference between the preparation method of this comparative example and that of Example 1 is as follows: In step two, all layers of the strip (layers 1 to 5) use the same scoring parameters, with the scoring direction along the width of the strip (perpendicular to the length of the strip). Scoring parameters: score spacing D = 2mm, score line length L to strip width S ratio L / S = 0.9, meaning the distance between the end of the score line and both edges of the strip is 1.5mm. The laser energy density is 4J / m, the laser frequency is 50kHz, and the score width is 20μm.

[0064] Comparative Example 2 This comparative example provides an amorphous stator core based on laser etching and its preparation method. The difference between the preparation method of this comparative example and that of Example 1 is as follows: Step eight uses the traditional single-segment isothermal longitudinal magnetic field annealing, specifically: the iron core is placed in a longitudinal magnetic field annealing furnace, heated to 320℃ at 5℃ / min, held for 40min, and a longitudinal magnetic field of 80kA / m is applied (the magnetic field direction is along the magnetic circuit direction of the iron core). After the holding period, the core is slowly cooled to room temperature with the furnace.

[0065] Comparative Example 3 This comparative example provides an amorphous stator core based on laser etching and its preparation method. The difference between the preparation method of this comparative example and that of Example 1 is as follows: In step two, all layers of the strip (layers 1 to 5) use the same scoring parameters, with the scoring direction along the width of the strip (perpendicular to the length of the strip). Scoring parameters: score spacing D = 2mm, score line length L to strip width S ratio L / S = 0.9, meaning the distance between the end of the score line and both edges of the strip is 1.5mm. The laser energy density is 4J / m, the laser frequency is 50kHz, and the score width is 20μm.

[0066] Step eight uses the traditional single-segment isothermal longitudinal magnetic field annealing, specifically: the iron core is placed in a longitudinal magnetic field annealing furnace, heated to 320℃ at 5℃ / min, held for 40min, and a longitudinal magnetic field of 80kA / m is applied (the magnetic field direction is along the magnetic circuit direction of the iron core). After the holding period, the core is slowly cooled to room temperature with the furnace.

[0067] Comparative Example 4 This comparative example provides an amorphous stator core based on laser etching and its preparation method. The difference between the preparation method of this comparative example and that of Example 1 is as follows: Step two is skipped, meaning that none of the five strips are laser-marked. Instead, they are directly subjected to lamination, stamping, stacking, curing, and gradient magnetic field annealing.

[0068] Comparative Example 5 This comparative example provides an amorphous stator core based on laser etching and its preparation method. The difference between the preparation method of this comparative example and that of Example 1 is as follows: In step eight, gradient annealing is performed using the same four-stage gradient temperature annealing as in Example 1, without applying a magnetic field throughout the process.

[0069] Comparative Example 6 This comparative example provides an amorphous stator core based on laser etching and its preparation method. The difference between the preparation method of this comparative example and that of Example 1 is as follows: Steps two and eight are skipped, meaning that none of the five strips are laser-etched; instead, they are directly laminated, stamped, stacked, cured, and sandblasted.

[0070] Comparative Example 7 This comparative example provides an amorphous stator core based on laser etching and its preparation method. The difference between the preparation method of this comparative example and that of Example 1 is as follows: The surface layers (layers 1 and 5) undergo laser scoring, with the scoring direction along the width of the strip. Scoring parameters: score spacing D = 50 mm, score line length L to strip width S ratio L / S = 0.9, meaning the distance between the end of the score line and both edges of the strip is 1.5 mm. Laser energy density is 4 J / m, laser frequency is 50 kHz, and score width is 20 μm. No scoring is applied to the interior layers (layers 2 to 4).

[0071] The loss data of all the prototype and comparative iron cores were measured using a soft magnetic AC device, and the results are shown in Table 1 below.

[0072] The above description discloses only preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A low-loss amorphous stator core based on laser marking, comprising a plurality of stator laminations stacked and bonded together, wherein the stator laminations are formed by stamping composite strip, characterized in that: The composite strip includes a parallel intermediate layer group and a surface layer group. The intermediate layer group includes at least one first amorphous alloy strip, and the surface layer group includes a second amorphous alloy strip located on the surface of the intermediate layer group. The surface of the first amorphous alloy strip has a plurality of laser-etched lines arranged at intervals of D1. The surface of the second amorphous alloy strip either does not have laser-etched lines or has a plurality of laser-etched lines arranged at intervals of D2. The line width of the laser etched lines is 5μm-40μm, 1mm≤D1≤30mm, and D2≥50mm.

2. The low-loss amorphous stator core based on laser etching according to claim 1, characterized in that: The laser marking lines on the surfaces of two adjacent layers of the first amorphous alloy strip form an included angle α, where 15°≤α≤90°.

3. The low-loss amorphous stator core based on laser etching according to claim 1, characterized in that: The laser marking lines on the surfaces of the two adjacent layers of the first amorphous alloy strip are perpendicular.

4. A low-loss amorphous stator core based on laser marking according to claim 1, characterized in that: The laser-etched lines are smooth, wavy lines formed by connecting several continuous pulse pits, with the pulse pit overlap ε≥0.

5.

5. A low-loss amorphous stator core based on laser etching according to claim 1, characterized in that: The distance between the end of the laser-etched line and the edge of the amorphous ribbon it is located is ≥1mm.

6. A low-loss amorphous stator core based on laser etching according to claim 1, characterized in that: It is obtained by stacking and bonding several stator laminations, followed by baking and curing, and then annealing with a gradient magnetic field. The gradient magnetic field annealing includes a magnetic field induction stage in which the temperature is maintained at 300℃~380℃ under a rotating magnetic field.

7. A method for preparing a low-loss amorphous stator core based on laser etching as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) Laser scribing is performed on the amorphous alloy strips respectively. The laser scribing lines on the surface of the first amorphous alloy strip used to form the intermediate layer group are arranged at intervals of D1. The laser scribing lines on the surface of the second amorphous alloy strip used to form the surface layer group are not laser scribing or are arranged at intervals of D2. (2) The amorphous ribbons after laser marking are stacked in sequence, and an adhesive is coated between adjacent layers. The composite ribbon is then heated and pressed to cure. (3) The composite strip is stamped to obtain stator laminations; (4) The stator laminations are glued together and stacked to form a core stack; (5) The iron core stack is baked and cured and subjected to gradient magnetic field annealing treatment, wherein the gradient magnetic field annealing includes a magnetic field induction stage in which the core is kept at 300℃~380℃ under a rotating magnetic field.

8. The method for preparing a low-loss amorphous stator core based on laser etching according to claim 7, characterized in that, In step (5), the gradient magnetic field annealing includes the following stages: (5-1) Preheating stage: Heat to 200℃ at a heating rate of 10-20℃ / min without applying a magnetic field; (5-2) Stress relaxation stage: Hold at a temperature of 200-300℃ for 10-30 minutes without applying a magnetic field; (5-3) Magnetic field induction stage: Keep warm in the temperature range of 300-380℃ for 20-40 min, apply a rotating magnetic field with a magnetic field strength of 70-100kA / m and a rotation speed of 2-5rpm; (5-4) Cooling and shaping stage: Cool to room temperature at a cooling rate of 3-5℃ / min, and remove the rotating magnetic field after maintaining it at 200℃ during the cooling process.

9. The method for preparing a low-loss amorphous stator core based on laser etching according to claim 7, characterized in that: In step (5), when D1≤5mm, the annealing temperature of the magnetic field induction stage is 300-340℃; when D1>5mm, the annealing temperature of the magnetic field induction stage is 350-380℃.

10. The method for preparing a low-loss amorphous stator core based on laser etching according to claim 7, characterized in that: In step (1), the laser marking parameters are: laser frequency 10-100 kHz, laser scanning rate 1000-6000 mm / s, and laser energy density 1-10 J / m.

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