Composite magnetic joint strip and manufacturing method thereof

Abstract

The invention discloses a composite magnetic joint strip and a manufacturing method thereof. The magnetic joint strip comprises a soft magnetic conductive carrier band and a hard magnetic material magnet unit array which is arranged at intervals along the length direction of the soft magnetic conductive carrier band, the magnetizing polarities of adjacent magnet units are opposite, and the magnetic conductive carrier band forms a closed loop path of magnetic induction lines of the magnet units. According to the invention, through a process path of assembling first and then magnetizing, the magnetic conductive carrier band is used as a conduction path of a magnetizing magnetic circuit, synchronous saturation magnetizing of the magnet unit array is realized, and the problems of difficult assembling and poor magnetic field uniformity caused by mutual repulsion of magnetized units in a traditional process are solved. The method has the outstanding advantages of high production efficiency, good product consistency and high magnetic energy utilization rate, and is suitable for large-scale production of the high-performance one-way strong-magnetic composite magnetic joint strip.

Description

Technical Field

[0001] This invention relates to the field of magnetic functional materials and device manufacturing technology, specifically to a high-performance composite magnetic strip with alternating polarity magnetic units and its manufacturing method. Background Technology

[0002] Composite magnetic strips are widely used in home, industrial, and automotive fields. For example, patent CN208570245U discloses a composite magnetic strip that combines magnetism and flexibility by encapsulating hard ferromagnetic magnet units in a polymer carrier tape.

[0003] However, traditional magnetic strip manufacturing processes have significant drawbacks: they typically involve first magnetizing the magnetic units and then assembling them into the carrier tape. Because the magnetized units possess strong magnetism, they attract or repel each other during assembly, making automated assembly difficult; the magnetic units easily adhere to the equipment; adjacent units may interfere with each other due to improper magnetic pole arrangement; production efficiency is low, and yield is difficult to guarantee; and the positioning accuracy of the magnetic units is affected.

[0004] In addition, the composite magnetic strip using patent CN208570245U has a low magnetic circuit efficiency because the non-magnetic cover and carrier tapes have high magnetic resistance. The magnetic lines of force generated by the magnetic unit diverge severely when passing through them, and a large amount of magnetic energy is wasted on overcoming the high magnetic resistance of the non-magnetic material. It cannot be effectively used for adsorption operations.

[0005] Therefore, there is an urgent need in this field for a high-efficiency and reliable strong magnetic composite magnetic strip that can avoid the above problems and a method for manufacturing it. Summary of the Invention

[0006] The technical problems to be solved by the present invention include two aspects: first, to provide a composite magnetic strip that forms a closed loop of magnetic field lines through a magnetically conductive carrier tape, thereby significantly improving the unidirectional magnetic attraction force; second, to provide a method for manufacturing the aforementioned magnetic strip, which completely solves the problems of magnetic interference and efficiency in traditional processes by first assembling an unmagnetized magnet and a magnetically conductive carrier tape, and then using the magnetic conduction effect of the carrier tape to magnetize the whole.

[0007] This invention provides a composite magnetic strip, characterized in that it comprises: a soft magnetic conductive carrier tape; an array of hard magnetic material magnet units spaced apart along the length direction of the carrier tape; and a magnetically conductive adhesive layer located between the magnet units and the magnetically conductive carrier tape; wherein the magnet unit array is configured such that adjacent magnet units have opposite magnetization polarities, and the magnetically conductive carrier tape and the magnetically conductive adhesive layer together constitute a closed loop path of the magnetic field lines of each magnet unit.

[0008] Furthermore, the magnetization direction of the magnet unit is perpendicular to the surface of the magnetic carrier tape.

[0009] Furthermore, the magnetically conductive adhesive layer is formed by curing an adhesive doped with soft magnetic filler.

[0010] Furthermore, the center-to-center spacing between adjacent magnet units is 1.2 to 3 times the width of a single magnet unit along its length.

[0011] Furthermore, the thickness of the soft magnetic conductive carrier tape is 0.1 mm to 1 mm and the relative permeability μr ≥ 100.

[0012] The present invention also provides a method for manufacturing the above-mentioned composite magnetic strip, characterized by comprising the following steps: S1: Assembly steps: Multiple unmagnetized hard magnetic material magnet units are fixed at preset intervals to the surface of a soft magnetic conductive carrier tape through a magnetically conductive adhesive layer to form an assembly; S2: Magnetization Step: Place the assembly in a magnetization device, so that the back side of the magnetic carrier tape contacts a magnetic support platform; use a magnetization head with N and S magnetization poles, align the two magnetization poles with two adjacent magnet units on the assembly; apply pulse excitation to the magnetization head to form a closed magnetization magnetic path that sequentially passes through the N pole of the magnetization head, the first magnet unit, the magnetic adhesive layer, the magnetic carrier tape, the magnetic adhesive layer, the second adjacent magnet unit, and then returns to the S pole of the magnetization head, thereby synchronously magnetizing the two adjacent magnet units to a state with opposite polarities.

[0013] Furthermore, the center distance between the N and S magnetizing poles of the magnetizing head is equal to the center distance between adjacent magnet units preset in the assembly.

[0014] Furthermore, in the magnetization step, a pulsed magnetic field is used for magnetization, and the intensity of the pulsed magnetic field is more than 1.2 times the intensity required to saturate the hard magnetic material.

[0015] Furthermore, the magnetization step is performed in a dedicated magnetization system, which includes a U-shaped magnetizing head with N and S magnetizing poles, a magnetic support platform for carrying the assembly, and a drive mechanism for stepping and conveying the assembly and aligning the magnetizing poles with the magnet unit to be magnetized.

[0016] Furthermore, the outer surface of the composite magnetic strip is covered with a protective coating layer.

[0017] Compared with the prior art, the present invention has the following significant advantages: High-efficiency magnetic circuit structure: Utilizing the high permeability of ferromagnetic materials, it provides a low magnetic resistance path for magnetic lines of force, which can effectively constrain, guide and concentrate magnetic flux to form a high-efficiency magnetic circuit, greatly reducing magnetic energy loss, thereby significantly enhancing the magnetic attraction of the composite magnetic strip on the opposite side of the magnetic carrier strip, and is particularly suitable for occasions that require strong magnetic force fixation. Magnetic pollution during assembly is eliminated: Since the magnetic units are in an unmagnetized state throughout the assembly process, there is no magnetic interference, making automated feeding, positioning and placement simple, fast and reliable, greatly improving production efficiency and yield. Simplified process and equipment: The semi-finished product strip step-by-step continuous magnetization process eliminates the need for complex tooling and polarity detection steps for handling magnetized magnets, and can manufacture magnetic strips of any length, reducing equipment costs and process complexity. It has strong versatility and is easy to automate and scale up manufacturing. Ensuring magnetic pole accuracy: Through the precise coordination of the magnetizing head and the magnet unit, a high-precision and highly consistent magnetic pole array can be formed, fundamentally guaranteeing product quality. Attached Figure Description

[0018] Figure 1 This is a three-dimensional structural diagram of the composite magnetic strip of Embodiment 1 of the present invention.

[0019] Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the strip along the AA direction (after magnetization).

[0020] Figure 3 This is a schematic diagram illustrating the principle of the magnetization step in this invention, showing the structure of a closed magnetic circuit.

[0021] Figure 4 This is a schematic diagram of the magnetization system in one embodiment of the present invention.

[0022] In the diagram: 1-Soft magnetic conductive carrier tape; 2-Hard magnetic material magnet unit; 21, 22-Adjacent magnet units; 3-Magnetic conductive adhesive layer; 4-Protective coating layer; 5-U-shaped magnetizing head; 50-Magnetic coil; 51-Magnetic core; 52-N magnetizing pole; 53-S magnetizing pole; 6-Magnetic support platform; 7-Pulse power supply; 8-Drive roller; Φ-Closed magnetic circuit flux path; D-Center distance between magnetizing poles; P-Center distance between magnet units. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are used to explain the present invention, but do not constitute a limitation on the scope of protection of the present invention.

[0024] Example 1: As Figure 1 and Figure 2As shown, this embodiment provides a basic composite magnetic strip. Its soft magnetic conductive carrier tape 1 is made of electrical pure iron with a thickness of 0.2 mm, and its relative permeability μr is measured to be >2000. The hard magnetic material magnet unit 2 is a cuboid sintered NdFeB (N45 grade) with dimensions of 4.0 mm (width) × 1.5 mm (height) × 10 mm (length). The center-to-center distance P between adjacent units is set to 6.0 mm.

[0025] The composite magnetic strip is formed by electroplating, spraying, dip coating or plastic wrapping processes to form a protective coating layer on the outer surface of the magnet unit and the magnetic carrier strip.

[0026] Preparation and properties of core component—magnetic adhesive layer 3: The magnetically conductive adhesive is prepared from the following components in parts by weight: epoxy resin E-44 (100 parts), curing agent polyamide 651 (50 parts), reduced iron powder (magnetic filler, 150 parts) with an average particle size of 3 μm, and silane coupling agent KH-550 (2 parts). After uniform mixing and degassing of the above components, the magnetically conductive adhesive is obtained. Indirect measurement using an impedance analyzer shows that its relative permeability μr after curing is approximately 18.

[0027] The magnetically conductive adhesive layer 3 is one of the key components of this invention. It establishes a low magnetic resistance connection channel between the magnet unit 2 and the magnetically conductive carrier tape 1, and is an indispensable part of forming an efficient closed magnetic circuit.

[0028] The manufacturing process steps are as follows: S1: Assembly. Using an automatic dispensing and mounting device, the above-mentioned magnetic adhesive is precisely applied to the magnetic carrier tape 1. Then, the unmagnetized neodymium iron boron magnet units 2 are mounted with a center distance of P=6.0mm. The assembly is cured at 120°C for 60 minutes to form a solid assembly. S2: Magnetizing. Use as follows: Figure 3 The magnetization system is shown. The U-shaped magnetizing head 5 is composed of a magnetizing coil 50 and a magnetizing core 51 made of silicon steel sheets. The center distance D between its two magnetizing poles (52, 53) is precisely machined to 6.0 mm (equal to P). The magnetic support platform 6 is a soft magnetic silicon steel block. The assembly is placed flat on the magnetic support platform 6, and the assembly is conveyed step by step by the drive roller 8 driven by the servo motor. When a pair of adjacent unmagnetized units (21, 22) move precisely to the underside of the magnetizing head 5 and are aligned with the N pole 52 and the S pole 53 respectively, the position sensor triggers the pulse power supply 7. The pulse power supply 7 applies a peak current to the coil of the magnetizing head 5, generating a pulsed magnetic field of approximately 3.8T at the magnetic poles (approximately 1.25 times the saturation magnetization field of N45 material). At this moment, as... Figure 3As indicated by arrow Φ, an efficient closed magnetization circuit is established: the magnetic flux starts from the N pole 52, is perpendicular to the magnetization unit 21 (becoming N pole upward) → enters the magnetic carrier 1 through the magnetically conductive adhesive layer 3 → is transversely conducted in the magnetic circuit to the area below the unit 22 → enters the unit 22 upward through the magnetically conductive adhesive layer 3 and reverses the magnetization (becoming S pole upward) → finally returns to the S pole 53.

[0029] The magnetic support platform 6 contacts the back side of the magnetic carrier tape 1. The magnetic circuit of the magnetic support platform 6 is parallel to the magnetic circuit of the magnetic carrier tape 1, which can reduce the transverse magnetic flux density and effectively avoid the saturation of the magnetization magnetic circuit that may occur when relying solely on the thin magnetic carrier tape 1 during the magnetization process.

[0030] The entire process is completed in one go within approximately 200 microseconds, synchronously and saturating two adjacent units with preset alternating polarities. The system then moves 2P steps to the next set of adjacent magnet units, repeating this process to achieve continuous production.

[0031] Performance testing and comparison: To verify the effectiveness of this invention, the following comparative experiments were conducted: Experimental group: Strips prepared using the method described in Example 1 and the magnetic adhesive; Traditional group: The traditional "magnetize first and then assemble" process is used to make a strip by manually pasting the magnetized unit onto the plastic base tape.

[0032] The magnetic field strength was measured at 2mm intervals along the center line of the sticker surface using a gaussmeter. The results are as follows: Group-average surface magnetic field (mT) Magnetic field homogeneity (standard deviation) Remarks The experimental group (of this invention) showed superior performance at 525 ± 8.2 mT. The traditional group had an assembly error of 498 ± 22.5 mT, resulting in poor uniformity. Test results show that, due to the use of a magnetically conductive adhesive layer and the formation of a highly efficient closed magnetization circuit, this invention not only achieves the best magnetization effect (highest magnetic field strength), but more importantly, obtains excellent magnetic field uniformity, fully demonstrating its technical superiority.

[0033] Example 2: The difference between this example and Example 1 lies in the formulation of the magnetically conductive adhesive layer, in order to demonstrate its feasibility.

[0034] The magnetic adhesive uses a two-component acrylate structural adhesive (100 parts main agent and 40 parts curing agent) as the matrix, and incorporates 120 parts of 300-mesh (approximately 48μm) carbonyl iron powder as a magnetic filler. This adhesive cures quickly and is suitable for high-speed production lines. After curing, it possesses sufficient magnetic conductivity and bonding strength, and also achieves good magnetization effects.

[0035] Example 3: This embodiment is an example Figure 4 As shown, this demonstrates the extensibility of the method.

[0036] Magnet unit 2 uses cylindrical samarium cobalt magnets (8mm in diameter), arranged in a double-row staggered pattern on the magnetic carrier belt 1. The magnetization system is equipped with two sets of parallel U-shaped magnetizing head units 5 with matching spacing and magnetic support platforms 6. The pulse power supply 7 applies magnetizing current to the coil of the magnetizing head 5, and the drive roller 8 driven by the servo motor steps and conveys the assembly, thereby simultaneously magnetizing the double-row magnets synchronously, with the principle being exactly the same as that of a single-row magnet.

[0037] The above embodiments are merely preferred embodiments of the present invention. It should be noted that, for those skilled in the art, any equivalent substitutions or adaptive modifications made to the material of the magnetic carrier tape (such as silicon steel, iron-nickel alloy, soft magnetic composite material), the shape and arrangement of the magnet units (such as tile shape to construct arc-shaped magnetic strips), the specific formulation of the magnetic adhesive, the process of the protective layer, and the use of other magnetization equipment layouts, without departing from the core concept of "using magnetic carrier tape and magnetic adhesive layer to form a closed magnetic circuit to achieve simultaneous magnetization after assembly", should be considered to fall within the protection scope of the present invention.

Claims

1. A composite magnetic strip, characterized in that, include: Soft magnetic conductive carrier tape; an array of hard magnetic material magnet units spaced apart along the length of the carrier tape; And a magnetically conductive adhesive layer located between the magnet unit and the magnetically conductive carrier strip; wherein the magnet unit array is configured such that the magnetization polarities of adjacent magnet units are opposite, and the magnetically conductive carrier strip and the magnetically conductive adhesive layer together form a closed loop path of the magnetic field lines of each magnet unit.

2. The composite magnetic strip according to claim 1, characterized in that: The magnetization direction of the magnet unit is perpendicular to the surface of the magnetic carrier tape.

3. The composite magnetic strip according to claim 1, characterized in that: The magnetically conductive adhesive layer is formed by curing an adhesive mixed with soft magnetic filler.

4. The composite magnetic strip according to claim 1, characterized in that: The center-to-center spacing between adjacent magnet units is 1.2 to 3 times the width of a single magnet unit along its length.

5. The composite magnetic strip according to claim 1, characterized in that: The thickness of the soft magnetic conductive carrier tape is 0.1 mm to 1 mm and the relative permeability μr ≥ 100.

6. A method for manufacturing a composite magnetic strip as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: Assembly steps: Multiple unmagnetized hard magnetic material magnet units are fixed at preset intervals to the surface of a soft magnetic conductive carrier tape through a magnetically conductive adhesive layer to form an assembly; S2: Magnetization step: Place the assembly in a magnetization device so that the back of the magnetic carrier tape contacts a magnetic support platform; use a magnetization head with N and S magnetization poles to align the two magnetization poles with two adjacent magnet units on the assembly. A pulse excitation is applied to the magnetizing head to form a closed magnetizing circuit that sequentially passes through the N pole of the magnetizing head, the first magnet unit, the magnetically conductive adhesive layer, the magnetically conductive carrier tape, the second adjacent magnet unit, and then returns to the S pole of the magnetizing head, thereby synchronously magnetizing the two adjacent magnet units to a state with opposite polarities.

7. The method according to claim 6, characterized in that: The center-to-center distance between the N and S poles of the magnetizing head is equal to the center-to-center distance between adjacent magnet units in the assembly.

8. The method according to claim 6 or 7, characterized in that: In the magnetization step, a pulsed magnetic field is used for magnetization, and the intensity of the pulsed magnetic field is more than 1.2 times the intensity required to saturate the hard magnetic material.

9. The method according to claim 6 or 7, characterized in that: The magnetization step is performed in a dedicated magnetization system, which includes a U-shaped magnetizing head with N and S magnetizing poles, a magnetic support platform for carrying the assembly, and a drive mechanism for stepping and conveying the assembly and aligning the magnetizing poles with the magnet unit to be magnetized.

10. The composite magnetic strip according to any one of claims 1 to 5, or the composite magnetic strip manufactured by the method according to any one of claims 6 to 9, characterized in that: Its outer surface is covered with a protective coating.

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