Magnet assembly and method of making and using same

Abstract

The application discloses a magnet assembly, a preparation method and application thereof. The magnet assembly comprises at least two magnet units, wherein: two adjacent magnet units have different magnetization directions; there is a welding point between the two adjacent magnet units; the magnet unit can have or not have a plating layer on the joint surface of the two adjacent magnet units, and the plating layer comprises other elements except Nd, Fe and B elements. The magnet assembly of the application significantly improves the connection strength of the magnet structure and / or the stability in a harsh environment such as high temperature and high humidity without changing the Halbach array mode of the magnet arrangement, and avoids unnecessary loss of magnet performance. Moreover, the preparation method of the magnet assembly of the application also significantly improves the assembly efficiency of the magnet assembly, and can be widely applied to large-scale production.

Description

Technical Field

[0001] This invention belongs to the field of magnet structure, and relates to a magnet component, its preparation method and application, and more particularly to a magnet component having at least two magnet units combined, its preparation method and application. Background Technology

[0002] Magnetic assemblies are typically composed of several magnets, forming a specific magnetic field distribution. In traditional magnetic assemblies, the arrangement and combination of magnets are often limited by material properties and magnetic field design, which to some extent restricts the optimization and application range of the magnetic field. The Halbach array is a special magnetic structure widely considered in engineering applications to be a near-ideal magnetic layout. This array aims to generate a stronger and more effective magnetic field within the same area of ​​magnetic units. In current technical practices, three magnets with magnetic repulsion properties are usually glued together to form the desired magnetic structure. However, this adhesive bonding method has a significant drawback: the connection strength at the bonded joints is relatively low. Therefore, in harsh environments such as high temperature and high humidity, these bonds are prone to delamination and breakage. This deficiency is particularly pronounced in applications with high requirements for humidity and heat testing, such as mobile phone cameras. Because devices like mobile phone cameras are frequently exposed to various complex environmental conditions during use, the stability and reliability requirements of the magnets are extremely high. If the magnet structure delaminates or breaks under these conditions, it will directly affect the performance and lifespan of the equipment.

[0003] Although welding has been reported as a method for fixing magnets together, this approach faces numerous challenges in practical applications. For example, the high temperatures during welding can alter the internal structure of the magnets, thereby reducing their magnetic properties. Furthermore, the stress generated during welding can cause microcracks in the magnets, which may propagate over time, eventually leading to magnet failure. Additionally, if low-melting-point metal solder is used to melt and penetrate into the gaps between magnets to achieve the connection, the introduction of the low-melting-point metal can affect the flatness of precision components, thus impacting the overall performance of the device. Moreover, even laser welding presents the following problems: ① Helbeck magnet assemblies are typically bonded together with adhesive and then further fixed by welding. In practice, laser welding requires a high degree of surface cleanliness for the magnet assemblies. After adhesive bonding, there may be excess adhesive at the welding points, necessitating adhesive removal to ensure a clean surface before welding, which reduces assembly efficiency. ② Laser welding machines operate at high temperatures, reaching up to 600–3000℃, which may lead to increased magnetic loss for temperature-sensitive neodymium iron boron magnets.

[0004] Therefore, improving the connection strength of magnet structures, especially their stability in harsh environments such as high temperature and high humidity, as well as avoiding excessive loss of magnet performance and improving assembly efficiency, have become the technical directions that urgently need to be improved in this field. Summary of the Invention

[0005] To address the aforementioned problems, the present invention provides a magnet assembly comprising at least two magnet units, wherein:

[0006] Two adjacent magnet units have different magnetization directions;

[0007] There is a weld point between two adjacent magnet units; and

[0008] The weld joint has at least one characteristic selected from the following:

[0009] (1) The welding point is located between the gaps on the end faces of the two adjacent magnet units, preferably between the gaps on the weak magnetic surfaces of the two adjacent magnet units.

[0010] (2) The magnetic flux attenuation rate of the magnet assembly before and after welding is ≤5%.

[0011] According to an embodiment of the present invention, the magnetic flux attenuation rate of the magnet assembly before and after welding is ≤4%, for example: 1%, 2%, 3%, 4%.

[0012] According to an embodiment of the present invention, in the magnet assembly, two adjacent magnet units have different magnetization directions. Preferably, the magnetization directions between two magnet units on either side of any magnet unit are opposite. Preferably, the magnet units in the magnet assembly are arranged in a Halbach array order.

[0013] According to embodiments of the present invention, there are no particular limitations on the shape of the weld joint. For example, the shape of the weld joint can be circular, elliptical, square, rectangular, near-circular, near-elliptical, near-square, near-rectangular, etc. Those skilled in the art should understand that the shape of the weld joint can be selected based on the welding process and the structure of the magnet unit to ensure the strength and stability of the weld joint. For example, a near-circular weld joint can provide a uniform stress distribution, while a near-elliptical weld joint can provide better strength in certain directions. Near-square or near-rectangular weld joints are suitable for applications requiring a larger contact area.

[0014] According to embodiments of the present invention, the magnet unit refers to an independent magnet. Specifically, the magnet unit can be a magnetic material with a specific geometry, such as cylindrical, cuboid, toroidal, or any other shape suitable for the target application. The size and shape of the magnet unit can be optimized according to the end use of the magnet assembly to achieve the desired magnetic properties and mechanical strength. For example, for applications requiring high magnetic field strength, a larger magnet unit can be used; while for applications requiring a compact design, a smaller magnet unit may be chosen. In embodiments of the present invention, neodymium iron boron permanent magnets can be used as magnet units.

[0015] According to an embodiment of the invention, the welding point is located in the gap between the end faces of two adjacent magnet units, these end faces being closely adjacent to ensure that the welding point can effectively connect the two magnet units. Preferably, the welding point is located in the gap between the weak magnetic surfaces of two adjacent magnet units, these weak magnetic surfaces being the relatively weaker magnetic parts of the magnet units. By welding between these gaps, the connection between the magnet units can be ensured to be both strong and stable, thereby improving the reliability and performance of the overall structure.

[0016] According to an embodiment of the present invention, the number Q of welding points between two adjacent magnet units can be any integer between 1 and 6. For example, the number of welding points can be 1, 2, 3, 4, 5, or 6. Further, the total number Q of welding points in the magnet assembly can satisfy the following relationship: (n-1)≤Q≤6*(n-1), preferably, 2*(n-1)≤Q≤3*(n-1); where n is the number of magnet units. The inventors have found through extensive experiments that if the number of welding points is too large, the magnetic flux of the magnet assembly will decrease significantly. Furthermore, too many welding points may also lead to more severe magnetic circuit degradation, resulting in a gradual decrease in the magnetic performance of the magnet assembly under prolonged use or high-temperature environments.

[0017] According to an embodiment of the present invention, the equivalent spherical diameter R (ESD) of at least one or all of the welding points is less than 1 mm, preferably less than 0.8 mm, for example 0.1 mm to 1 mm, preferably 0.1 mm to 0.3 mm, such as 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm or 0.8 mm.

[0018] According to an embodiment of the present invention, the length L of any welding point between two adjacent magnet units q The following relationship can be satisfied: 5% * L ≤ L q ≤40%*L, preferably, 6%*L≤L q ≤20%*L; where L is the average of the sum of the lengths of the two adjacent magnet units in the direction parallel to the contact surface between the two adjacent magnet units.

[0019] According to an embodiment of the present invention, the total length L of the welding point between two adjacent magnet units is... Q The following relationship must be satisfied: 10% * L ≤ L Q ≤80%*L, preferably, 12%*L≤L Q ≤50%*L; where: L is the average of the sum of the lengths of the two adjacent magnet units in the direction parallel to the contact surface between the two adjacent magnet units.

[0020] Through extensive experimentation, the inventors discovered that excessively long weld joints can lead to marginal effects, such as uneven heat distribution and excessively high or low temperatures at the weld edges. This can result in weld cracks, porosity, or other defects, ultimately affecting the strength and reliability of the entire welded structure. This invention, by controlling the length and size of the weld joints within the aforementioned range, ensures excellent weld strength while maintaining excellent magnetic flux in the welded magnet assembly.

[0021] According to an embodiment of the present invention, the minimum distance S between the outer peripheral edge of the welding point and the surface of the magnet unit is... q ≥1mm; preferably, 5% * L ≤ S q <50%*L. Preferably, the distance S from the outer periphery of the welding point to the center of the contact surface between the two adjacent magnet units is... c The following relationship must be satisfied: 15% * L ≤ S c <50%*L; preferably, 25%*L≤S c <50%*L. The inventors unexpectedly discovered through extensive experiments that if Sc≤15%*L, the distance between the welding point and the center of the contact surface between the two adjacent magnet units is too small, which will significantly reduce the magnetic flux of the magnet assembly.

[0022] According to an embodiment of the present invention, the depth D of the welding point toward the contact surface between the two adjacent magnet units is... q Satisfy the following relationship: D q ≤H*50%, preferably, H*5%≤D q ≤H*30%; where: H is the minimum length of the two adjacent magnet units in the direction parallel to the contact surface between the two adjacent magnet units.

[0023] According to an embodiment of the present invention, an adhesive layer may also be included between two adjacent magnet units. This allows the magnet assembly to be simply fixed first, and then further welded. Preferably, the thickness of the adhesive layer is 0.01-0.1 mm. For example, the adhesive layer is prepared from glue, adhesive, etc.

[0024] According to an embodiment of the present invention, the magnet assembly includes at least two magnet units, wherein:

[0025] Two adjacent magnet units have different magnetization directions;

[0026] There is a welding point between two adjacent magnet units; and the welding point includes Nd, Fe and B elements as well as other elements besides Nd, Fe and B elements.

[0027] According to an embodiment of the present invention, the welding point may have the features described above.

[0028] According to an embodiment of the present invention, the magnet unit may have a coating (also known as a "white sheet" in the industry) or no coating (also known as a "black sheet" in the industry) on the mating surface with two adjacent magnet units, and the coating contains elements other than Nd, Fe and B.

[0029] According to an embodiment of the present invention, the elements other than Nd, Fe and B are selected from one, two or more of Ni, Zn, Cu, P, Mo, etc.

[0030] According to an embodiment of the present invention, the coating is a metal coating. The present invention is not limited to the type of metal coating, for example, it can be a Ni coating, a Zn coating, a Ni-Cu-Ni coating, a Cu-Ni coating, or a Zn-Ni coating.

[0031] According to an embodiment of the present invention, the thickness of the coating can be 1 to 30 μm, for example 2 to 25 μm, preferably 5 to 20 μm, more preferably 8 to 15 μm, and exemplary values ​​are 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm.

[0032] According to embodiments of the present invention, the magnet units may optionally include, or not include, an adhesive layer such as glue or adhesive, in addition to the welding points. When an adhesive layer is included, the thickness of the adhesive layer is 0.01-0.1 mm. For example, the glue or adhesive used in the adhesive layer can be a material known in the art, such as one or more selected from epoxy resin, polyurethane, silicone, AB glue, and anaerobic adhesive.

[0033] According to an embodiment of the invention, before two adjacent magnet units are joined together by welding points, the magnet units may optionally be magnetized or unmagnetized magnet units. Preferably, magnetized magnet units may be joined by welding, or welded magnet units may be magnetized. It should be understood that the magnetization should give the magnet units a magnetization direction as described above, such as the magnetization direction sequence of a Halbach array. Preferably, magnetization may be performed obliquely along the edge of the magnet assembly.

[0034] According to an embodiment of the present invention, before two adjacent magnet units are joined together by a welding point, the magnet units may optionally be diffused magnets or undiffused magnets. Preferably, the magnet units may be diffused first, and then welded.

[0035] According to embodiments of the present invention, the magnetic properties of two adjacent magnet units may be the same or different. As an example, in the magnet assembly, the central magnet unit has a higher Hcj than the other magnet units. More preferably, in the magnet assembly, the Hcj of the magnet units gradually decreases from the central magnet unit to the magnet units on either side. Alternatively, as an example, in the magnet assembly, the central magnet unit has a lower Hcj than the other magnet units. More preferably, in the magnet assembly, the Hcj of the magnet units gradually increases from the central magnet unit to the magnet units on either side.

[0036] According to an embodiment of the present invention, the magnet unit may optionally have or not have a chamfer. Preferably, the magnets whose weak magnetic surfaces are adjacent to each other in the magnet assembly are chamfered. Preferably, the chamfering is an R-shaped chamfer. For example, R is 0.1-0.3 mm.

[0037] According to an embodiment of the present invention, the magnet unit may be selected from neodymium iron boron magnets.

[0038] The present invention also provides a method for preparing the magnet assembly, comprising joining the two adjacent magnet units by welding them together at welding points.

[0039] According to embodiments of the present invention, the specific welding method is not limited, that is, all welded magnet assemblies having feature points (1) to feature points (9) have reliable weld strength and an acceptable range of magnetic flux reduction for the magnet assemblies. Preferably, the welding method can be laser welding. Exemplarily, the laser welding can be pulsed welding, such as using QCW (Quasi-Continuous Wave) laser welding. For example, the pulse width of the laser welding is 50-150ms, exemplarily 50ms, 60ms, 70ms, 80ms, 90ms, 100ms, 110ms, 120ms, 130ms, 140ms, and 150ms; the frequency is 50-350Hz, preferably 100-300Hz, exemplarily 50Hz, 100Hz, 120Hz, 150Hz, 180Hz, 200Hz, 240Hz, 300Hz, and 350Hz; and the peak power is 10-40%, exemplarily 10%, 15%, 18%, 20%, 25%, 30%, 35%, and 40%.

[0040] According to an embodiment of the present invention, in the method for preparing the magnet assembly, before two adjacent magnet units are welded together by welding points, the magnet units may optionally be magnetized magnet units or unmagnetized magnet units. Preferably, magnetized magnet units can be joined by welding, or welded magnet units can be magnetized.

[0041] According to an exemplary embodiment of the present invention, the method for preparing the magnet assembly includes the following steps:

[0042] S1: Fabrication of magnet units;

[0043] S2: Magnetize the magnet units and arrange the magnets according to the assembly requirements to form a magnet assembly; optionally, the magnet assembly is placed in a fixing fixture;

[0044] S3: Apply adhesive to the magnet assembly and then press and cure it;

[0045] S4: Laser welding is performed along the end face joint of adjacent magnets or the weak magnetic surface joint of magnets.

[0046] According to an exemplary embodiment of the present invention, the method for preparing the magnet assembly includes the following steps:

[0047] S1: Fabrication of magnet units;

[0048] S2: Arrange the magnets according to the assembly requirements to form a magnet assembly; optionally, the magnet assembly is placed in a fixing fixture;

[0049] S3: Apply adhesive to the magnet assembly and then press and cure it;

[0050] S4: Magnetize the magnet assembly according to the required polarity direction;

[0051] S5: Laser welding is performed along the end face joint of adjacent magnets or the weak magnetic surface joint of magnets.

[0052] In one embodiment of the present invention, steps S4 and S5 can be interchanged.

[0053] In one embodiment of the present invention, step S3 may also be omitted.

[0054] In one embodiment of the present invention, the method for preparing the magnet assembly further includes surface treatment of the magnet unit obtained in step S1 to obtain a coating. Preferably, the coating is a metallic coating, such as a Ni coating, a Zn coating, a Ni-Cu-Ni coating, a Cu-Ni coating, or a Zn-Ni coating. During laser welding, laser welding is performed along the coating at the end face joint of adjacent magnets or along the coating at the weak magnetic surface joint of the magnets.

[0055] In one embodiment of the present invention, the curing temperature is 40-150°C, exemplarily 40°C, 60°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, and 150°C; the curing time is 15-60 min, exemplarily 15 min, 20 min, 30 min, 40 min, 50 min, and 60 min.

[0056] In one embodiment of the present invention, the method for preparing the magnet assembly may further include, during welding, using a cover plate fixture containing holes or trajectories identical to the welding point to accurately position the welding equipment at the welding location for welding.

[0057] In one embodiment of the present invention, the method for preparing the magnet assembly may further include using a visual detector to accurately locate the joint of the magnet unit and achieve precise laser welding, so as to minimize the magnetic flux loss of the magnet assembly.

[0058] The present invention also provides an electric motor, the electric motor including the above-described magnet assembly.

[0059] According to an embodiment of the present invention, the motor is a linear motor. For example, the motor includes a stator assembly and a moving assembly. Preferably, the stator assembly is fixedly mounted on the device, and the moving assembly can move along a linear direction on the stator assembly. The stator assembly and the moving assembly interact magnetically to achieve contactless driving.

[0060] According to an embodiment of the present invention, the motor further includes a control system that can be integrated with the control system of the magnetic attraction component to achieve precise synchronous control, thereby improving the performance of the motor.

[0061] According to an embodiment of the present invention, the motor further includes a drive device, and the drive device and the magnet assembly are respectively disposed in the stator assembly and the moving assembly.

[0062] The present invention also provides a photographing or video recording device, which includes the aforementioned motor. As an example, the photographing or video recording device further includes optical elements and a photosensitive element.

[0063] The present invention also provides an electronic device, which includes the above-described motor.

[0064] According to an embodiment of the present invention, the electronic device further includes a housing, and the photographing or video recording device is disposed on the housing.

[0065] Beneficial effects:

[0066] The magnet assembly of this invention overcomes the repulsive force between magnets through welding. Without altering the magnet arrangement, it significantly improves the connection strength of the magnet structure and / or its stability in harsh environments such as high temperature and high humidity. This makes the magnet assembly less prone to delamination due to decreased adhesion caused by high temperature and humidity, thus avoiding unnecessary loss of magnet performance. Furthermore, the manufacturing method of the magnet assembly of this invention significantly improves the assembly efficiency and can be widely applied to large-scale production. Attached Figure Description

[0067] Figure 1 This is a schematic diagram of the welding points on the weak magnetic surface of the Heilbeck magnet assembly in Example 1.

[0068] Figure 2 This is a schematic diagram of the strong magnetic surface of the Heilbeck magnet assembly for Comparative Example 1.

[0069] Figure 3 for Figure 1 The top view of the weak magnetic surface of the Heilbeck magnet assembly in Example 1.

[0070] Figure 4 for Figure 1 The front view, i.e., the front view of the Heilbeck magnet assembly in Example 1.

[0071] Figure 5 This is a left view of the Heilbeck magnet unit in Example 1.

[0072] Figure 6 This is a schematic diagram of the fixed support structure.

[0073] Figure 7 This is a schematic diagram of the fixed support structure.

[0074] Figure 8 This is a schematic diagram of the welding point on the weak magnetic surface of the Heilbeck magnet assembly in Example 6.

[0075] Figure 9 This is a schematic diagram of the welding points on the weak magnetic surface of the Heilbeck magnet assembly in Example 9. Detailed Implementation

[0076] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0077] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0078] Reference Figure 1-5 A magnet assembly, the magnet assembly comprising at least two magnet units, wherein:

[0079] Two adjacent magnet units have different magnetization directions, and the magnetization directions of the two magnet units on either side of any magnet unit are opposite. Preferably, the magnet units in the magnet assembly are arranged in the order of a Helbeck array.

[0080] There is a weld point between two adjacent magnet units; and the weld point has at least one characteristic selected from the following:

[0081] (1) The welding point is located between the gaps on the end faces of two adjacent magnet units;

[0082] (2) The magnetic flux attenuation rate of the magnet assembly before and after welding is ≤5%.

[0083] [Number of welding points q]

[0084] The number of welding points q between two adjacent magnet units is any integer between 1 and 6.

[0085] Total number of weld points Q

[0086] The total number of welding points Q of the magnet assembly satisfies the following relationship: (n-1)≤Q≤4*(n-1), where n is the number of magnet units; preferably, 2*(n-1)≤Q≤3*(n-1).

[0087] [Equivalent circle diameter R of the weld joint]

[0088] The equivalent circle diameter R of at least one or all of the welding points is less than 1 mm; preferably, the equivalent circle diameter R of all welding points is less than 0.8 mm; for example, the equivalent circle diameter R of all welding points is 0.1 mm to 1 mm, preferably 0.1 mm to 0.3 mm.

[0089] Length L of the welding point q 】

[0090] The length L of any weld point between two adjacent magnet units q The following relationship must be satisfied: 5% * L ≤ L q ≤40%*L, where L is the average of the sum of the lengths of two adjacent magnet units in the direction parallel to the contact surface between the two adjacent magnet units, preferably, 6%*L≤L q ≤20%*L.

[0091] Total length L of the weld joint Q 】

[0092] The total length L of the weld joint between two adjacent magnet units Q The following relationship must be satisfied: 10% * L ≤ L Q ≤80%*L, where L is the average of the sum of the lengths of two adjacent magnet units in the direction parallel to the contact surface between the two adjacent magnet units; preferably, 12%*L≤L Q ≤40%*L.

[0093] The minimum distance S between the outer periphery of the welding point and the surface of the magnet unit q 】

[0094] The minimum distance S between the outer periphery of the welding point and the surface of the magnet unit. q ≥1mm; preferably, 5% * L ≤ S q <50%*L.

[0095] Preferably, the distance S from the outer periphery of the welding point to the center of the contact surface between two adjacent magnet units is... c The following relationship must be satisfied: 15% * L ≤ S c <50%*L; preferably, 25%*L≤S c <50%*L;

[0096] The depth D of the welding point towards the contact surface between two adjacent magnet units. q 】

[0097] The depth D of the welding point toward the contact surface between two adjacent magnet units. q Satisfy the following relationship: D q ≤H*50%, preferably, H*5%≤D q ≤H*30%; where: H is the minimum length of two adjacent magnet units in the direction parallel to the contact surface between the two adjacent magnet units.

[0098] [Shape of the weld joint]

[0099] The shape of the welding point can be circular, elliptical, square, rectangular, near-circular, near-elliptical, near-square, near-rectangular, etc.

[0100] Composition of a weld joint

[0101] There is a welding point between two adjacent magnet units; and the welding point includes Nd, Fe and B elements as well as other elements besides Nd, Fe and B elements.

[0102] Preferably, the magnet unit may have a coating on the mating surface with two adjacent magnet units, or it may not have a coating. The coating contains elements other than Nd, Fe and B.

[0103] Preferably, the elements other than Nd, Fe and B are selected from one, two or more of Ni, Zn, Cu, P, Mo, etc.

[0104] Preferably, the coating is a metallic coating. For example, it can be a Ni coating, a Zn coating, a Ni-Cu-Ni coating, a Cu-Ni coating, or a Zn-Ni coating.

[0105] Preferably, the thickness of the coating can be 1–30 μm, for example 2–25 μm, more preferably 5–20 μm, and even more preferably 8–15 μm.

[0106] [Adhesive Layer]

[0107] In addition to the solder joints, the magnet units may optionally include or exclude adhesive layers such as glue or adhesives. For example, the adhesives or adhesives used in the bonding layers may be selected from one or more of epoxy resin, polyurethane, silicone, AB glue, and anaerobic adhesives.

[0108]

Magnet Unit

[0109] Before two adjacent magnet units are joined together by a welding point, the magnet units can optionally be magnetized magnet units or unmagnetized magnet units.

[0110] The magnet unit can be a neodymium iron boron magnet, such as a sintered neodymium iron boron magnet with the grade 48H.

[0111] Preferably, the magnetized magnet units can be joined together by welding, or the welded magnet units can be magnetized.

[0112] Preparation Example 1: Preparation of Magnet Unit

[0113] In Examples 1-11 and Comparative Examples 1-4 below, sintered NdFeB magnets of grade 48H are used. The NdFeB magnets are divided into magnet units with the following dimensions: 15mm*5mm*0.9mm. The side with the largest area is selected as the welding contact surface, that is, the corresponding welding contact surfaces are 15mm*5mm. The length L of the magnet unit is 15mm, the width W is 5mm, and the height H is 0.9mm.

[0114] Example 1

[0115] A method for fabricating a magnet assembly includes processing the magnet unit of fabrication example 1 as follows:

[0116] S1: Same as in Preparation Example 1, prepare neodymium iron boron magnet substrate to obtain 30 magnet units with a diameter of 15mm*5mm*0.9mm;

[0117] S2: Place three NdFeB magnet units in a fixed fixture and magnetize them according to the Hellbeck magnetization method to prepare 10 Hellbeck magnet assemblies. The fixed fixture is a 3mm thick metal slotted fixture. Figure 6 );

[0118] S3: Apply adhesive to the magnet assembly and then press and cure it;

[0119] Apply epoxy adhesive (F-44 type phenolic epoxy resin) to the adjacent surfaces of the magnetized NdFeB magnet units using a dispensing device. Then, use a transverse pressing device to press the three NdFeB magnet units together. Place the pressed Heilbeck magnet assembly into an oven for curing at 100℃ for 40 minutes. The average thickness of the cured adhesive layer is 0.04 mm. Randomly select 10 cured Heilbeck magnet assemblies, measure the magnetic flux and calculate the average value, denoted as M1; measure the shear force and calculate the average value, denoted as N1.

[0120] S4: For the 10 magnet components in step S3, along the weak magnetic surface of the Halbec magnet component (e.g., Figure 1 Laser welding is performed at the joint between S14 and S24 shown in the figure. After welding, the magnetic flux of the magnet assembly is measured and the average value is recorded as M2; the shear force is measured and the average value is recorded as N1. The magnetic flux attenuation rate before and after welding is calculated as (M1-M2) / M1*100%, and the shear force increase ratio is calculated as (N1-N2) / N1*100%.

[0121] The specific welding parameters are shown in Table 1, and the characteristic parameters of the welded joints are shown in Table 2.

[0122] Examples 2-5

[0123] The same process steps as in Example 1 are used, except that between steps S1 and S2, step S11 is added: the magnet unit is surface treated to obtain a metal coating. The specific coating composition and thickness are shown in Table 1. The coating thickness is calculated by randomly selecting 3 points on the coating surface of each of the 30 magnet units and measuring the thickness at 90 points.

[0124] Examples 6-8

[0125] The same process steps as in Example 2 are used, except that: Step S2: Five neodymium iron boron magnet units are placed in a fixed fixture and magnetized according to the Heilbeck magnetization method to prepare the Heilbeck magnet assembly.

[0126] Example 9

[0127] The magnet unit prepared in Example 1 was processed as follows:

[0128] S1: Same as in Preparation Example 1, prepare a neodymium iron boron magnet substrate to obtain a magnet unit of 15mm*5mm*0.9mm;

[0129] S2: Place two NdFeB magnet units in a fixed fixture and magnetize them in a parallel magnetization manner to prepare a magnet assembly;

[0130] The remaining preparation methods are the same as in Example 2.

[0131] Example 10

[0132] The same process steps as in Example 2 are used, except that:

[0133] S2: Place every 3 neodymium iron boron magnet units in a fixed fixture without magnetizing;

[0134] Add step S4' after step S4:

[0135] S4': Magnetize the magnet assembly welded in step S4 according to the Heilbeck method to obtain the Heilbeck magnet assembly.

[0136] Example 11

[0137] The same process steps as in Example 1 are used, except that between steps S1 and S2, there is an additional step S11: surface treatment of the magnet unit to obtain a metal coating. The specific coating composition and thickness are shown in Table 1.

[0138] Comparative Example 1

[0139] A method for preparing a magnet assembly, which differs from Example 2 only in that: S4: the strong magnetic surface of the Hilbeck magnet assembly (e.g., Figure 2 Laser welding is performed at the joint between S13 and S23 shown in the figure.

[0140] Comparative Example 2

[0141] A method for preparing a magnet component, which differs from Example 3 only in that the pulse width in step S4 is 180 ns.

[0142] Comparative Example 3

[0143] A method for preparing a magnet component, which differs from Example 4 only in that the frequency in step S4 is 350KHz.

[0144] Comparative Example 4

[0145] A method for preparing a magnet component, which differs from Example 5 only in that the peak power in step S4 is 45%.

[0146] Table 1. Coating and laser welding parameters for Examples 1-11 and Comparative Examples 1-4

[0147]

[0148] Table 2 Welding point parameters of Examples 1-13 and Comparative Examples 1-4

[0149]

[0150] The magnetic flux and shear force of the magnet assemblies in Examples 1-12 and Comparative Examples 1-4 were measured using the following methods:

[0151] 1) Magnetic flux: The magnetic flux of a magnet is measured by a magnetometer.

[0152] 2) The magnetic flux attenuation rate represents the average magnetic flux attenuation rate of the magnet assembly before and after laser welding, i.e., magnetic flux attenuation rate = (M1-M2) / M1*100%, where: M1 represents the magnetic flux of the magnet assembly before welding (i.e., M1 is the magnetic flux after magnetizing the magnet unit in step S2 or the magnetic flux after magnetizing the magnet assembly in step S4'), and M2 represents the magnetic flux of the magnet assembly after welding.

[0153] 3) Shear force: Tested according to GB / T 7124-2008.

[0154] The specific test results are shown in Table 3.

[0155] Table 3 Performance of Examples 1-11 and Comparative Examples 1-4

[0156]

[0157]

[0158] The above results indicate that, when laser welding is performed using an adhesive layer formed by glue or similar materials between the end faces of two adjacent magnet units of the magnet assembly, a Heilbeck magnet assembly with a magnetic flux attenuation rate of 3.00% can be obtained by increasing the welding frequency. Furthermore, as the laser frequency increases, the overlap of the welding points becomes higher. Under the same pulse width and peak power, welding points with high overlap have shorter weld lengths, which easily lead to cracks at the weld seam, thus hindering the improvement of the shear force of the magnet assembly. In addition, as the pulse width increases during laser welding, the equivalent circular area of ​​the welding point becomes larger, increasing the magnetic flux attenuation rate of the magnet assembly after welding. When the welding point is too large, it can also easily lead to edge effects (such as uneven heat distribution, excessively high or low temperatures at the weld edge), resulting in cracks, porosity, or other defects in the weld seam, thereby affecting the strength of the magnet assembly after welding. Furthermore, with the increase of peak power during laser welding, the penetration ability and welding temperature increase, resulting in excessively deep weld joints. Excessive weld depth can affect the magnetic field strength of the strong magnetic surface of the magnet unit, thus increasing the magnetic flux loss of the magnet assembly. Further, this invention addresses this by applying a coating to the joint surface of two adjacent magnet units, facilitating welding and improving the magnetic flux attenuation rate and shear force after welding. The weld joint, located on the strong magnetic surface, is the application surface of the Helbeck magnet assembly. Therefore, while welding at the strong magnetic surface of the magnet unit increases the strength of the magnet assembly, it also significantly increases the magnetic flux attenuation rate. Consequently, the stability and reliability of the relative magnetic field decrease during frequent use of the magnet assembly. This invention addresses this by optimizing the number of weld joints between the end faces of two adjacent magnet units, the equivalent circle diameter R of the weld joint, and the length L of the weld joint. q The total length L of the welding point Q The minimum distance S between the outer periphery of the welding point and the surface of the magnet unit. q The depth D of the welding point toward the contact surface between the two adjacent magnet units. q The coating type at the welding points, without altering the Helbeck array arrangement of the magnets, significantly improves the connection strength of the magnet structure and its stability under harsh environments such as high temperature and high humidity, avoiding unnecessary loss of magnet performance. Furthermore, the fabrication method of the magnet assembly in this invention significantly improves the assembly efficiency of the magnet assembly, enabling its widespread application in mass production.

[0159] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a magnet assembly, characterized in that, The preparation method includes joining two adjacent magnet units by welding them together at welding points; The welding method is laser welding, wherein the pulse width of the laser welding is 50~150ms; the frequency is 50~300Hz; and the peak power is 10~40%. The magnet assembly includes at least two magnet units, wherein: Two adjacent magnet units have different magnetization directions; There is a welding point between two adjacent magnet units; and the magnet unit has a coating on the bonding surface with the two adjacent magnet units, the coating being a Ni coating, a Zn coating, a Ni-Cu-Ni coating, a Cu-Ni coating, or a Zn-Ni coating. The thickness of the coating is 8~15μm; The welding point has the following characteristics: (1) The welding point is located between the gaps of the weak magnetic surfaces of the two adjacent magnet units; (2) The magnetic flux attenuation rate of the magnet assembly before and after welding is ≤5%; The number q of welding points between two adjacent magnet units is any integer between 1 and 6; The total number Q of welding points in the magnet assembly satisfies the following relationship: 2 (n-1)≤Q≤3 (n-1), where n is the number of magnet units; The equivalent circle diameter R of at least one or all of the welding points is 0.1 mm to 0.3 mm; The length L of any welding point between two adjacent magnet units q Satisfying the following relationship: 6% L≤L q ≤20% L, where L is the average of the sum of the lengths of the two adjacent magnet units in the direction parallel to the contact surface between the two adjacent magnet units; The total length L of the weld joint between two adjacent magnet units Q Satisfying the following relationship: 12% L≤L Q ≤40% L, where L is the average of the sum of the lengths of the two adjacent magnet units in the direction parallel to the contact surface between the two adjacent magnet units; The minimum distance S between the outer periphery of the welding point and the surface of the magnet unit. q 25% L≤S q <50% L; The distance S from the outer periphery of the welding point to the center of the contact surface between the two adjacent magnet units c Satisfying the following relationship: 25% L≤S c <50% L; The depth D of the welding point toward the contact surface between the two adjacent magnet units q The following relationship must be satisfied: H 5%≤D q ≤H 30%, where H is the minimum length of the two adjacent magnet units in the direction parallel to the contact surface between the two adjacent magnet units.

2. The method for preparing the magnet assembly as described in claim 1, characterized in that, In the magnet assembly, two adjacent magnet units have different magnetization directions, and the magnetization directions between two magnet units on either side of any magnet unit are opposite.

3. The method for preparing the magnet assembly as described in claim 2, characterized in that, The magnet units in the magnet assembly are arranged in the order of the Helbeck array.

4. The method for preparing the magnet assembly according to any one of claims 1-3, characterized in that, The shape of the welding point is circular, elliptical, square, rectangular, near-circular, near-elliptical, near-square, or near-rectangular.

5. The method for preparing the magnet assembly according to any one of claims 1-3, characterized in that, The magnet units may or may not contain adhesive or bonding layers, except for the welding points. The adhesive or bonding layer may be selected from one or more of epoxy resin, polyurethane, silicone, AB glue and anaerobic glue.

6. The method for preparing the magnet assembly as described in claim 1 or 2, characterized in that, Before two adjacent magnet units are joined together by a welding point, the magnet unit is either a magnetized magnet unit or an unmagnetized magnet unit.

7. The method for preparing the magnet assembly as described in claim 6, characterized in that, The magnetized magnet units are joined together by welding, or the welded magnet units are magnetized.

8. The preparation method according to any one of claims 1-3, characterized in that, Includes the following steps: S1: Fabrication of magnet units; S2: Magnetize the magnet units and arrange the magnets according to the assembly requirements to form a magnet assembly; place the magnet assembly in the fixing fixture; S3: Apply adhesive to the magnet assembly and then press and cure it; S4: Laser welding is performed along the end face joints of adjacent magnets or the joints of the weak magnetic surfaces of magnets.

9. The preparation method according to any one of claims 1-3, characterized in that, Includes the following steps: S1: Fabrication of magnet units; S2: Arrange the magnet units according to the assembly requirements to form a magnet assembly; place the magnet assembly in a fixing fixture; S3: Apply adhesive to the magnet assembly, then press and cure it; S4: Magnetize the magnet assembly according to the required polarity direction; S5: Laser welding is performed along the end face joint of adjacent magnets or the joint of the weak magnetic surface of the magnet.

10. The method for preparing the magnet assembly as described in claim 9, characterized in that, The order of steps S4 and S5 is swapped.

11. The preparation method according to claim 8, characterized in that, The method for preparing the magnet assembly further includes surface treatment of the magnet unit obtained in step S1 to obtain a coating.

12. The preparation method according to any one of claims 1-3, characterized in that, The method for preparing the magnet assembly also includes, during welding, using a cover plate fixture containing holes or tracks identical to the welding point to accurately position the welding equipment at the welding location for welding.

13. The preparation method according to any one of claims 1-3, characterized in that, The method for preparing the magnet assembly also includes using a visual detector to accurately locate the joint of the magnet unit and perform laser welding.

14. An electric motor, characterized in that, The motor includes a magnet assembly prepared by the preparation method according to any one of claims 1-13.

15. The motor as described in claim 14, characterized in that, The motor includes a stator assembly and a moving assembly.

16. The motor as described in claim 15, characterized in that, The motor also includes a control system, which is integrated with the control system of the magnetic attraction component.

17. The motor according to any one of claims 14-16, characterized in that, The motor also includes a drive device, and the drive device and the magnet assembly are respectively disposed in the stator assembly and the moving assembly.

18. A photographing or video recording device, characterized in that, The photographing or video recording device includes the motor described in any one of claims 14-17.

19. An electronic device, characterized in that, The electronic device includes the motor as described in any one of claims 14-17.

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