molding apparatus

Abstract

The utility model discloses a forming device which comprises a first magnetic conducting block and a second magnetic conducting block. The first magnetic conducting block comprises multiple magnetic blocks with different relative magnetic conductivities in parallel and arranged along the horizontal direction. The bottom of the multiple magnetic blocks forms an arc-shaped groove. The second magnetic conducting block comprises multiple magnetic blocks with different relative magnetic conductivities in parallel and arranged along the horizontal direction. The top of the multiple magnetic blocks forms a semicircular protrusion. The semicircular protrusion is located in the space formed by the arc-shaped groove. An arc-shaped mold cavity is arranged between the arc-shaped groove and the semicircular protrusion. The device can make the obtained magnet have more uniform magnetic force line angle θ and residual magnetism Br, and can reduce the cracking rate and sound pressure level.

Description

Technical Field

[0001] This utility model relates to a molding device. Background Technology

[0002] The following forming devices exist in the prior art: Patent CN110783051A achieves radial orientation by adjusting the mold structure, but its 90° angled magnetic plate design causes extreme unevenness in the magnetic field strength of the inner and outer arcs, resulting in cracking of the blank and failure to form. At the same time, the design of the two magnetic blocks at both ends of the outer arc will create a sharp magnetic field divergence effect, causing severe deflection of the magnetic lines of force, which will aggravate the angle deflection of the edge magnetic lines of force, resulting in a poor edge focusing effect; Patent CN116344190A achieves radial orientation by heating the sheet material after processing it into square pieces, clamping it with a clamp after heating to a certain degree, and bending the square pieces. Since neodymium iron boron is a brittle material, the bending strength of the product cannot be met by this method, the product is prone to breakage, and the bending angle is inconsistent with the angle of magnetic line deflection; Patent CN107579628A discloses a method for manufacturing radially oriented rare earth permanent magnet ferrite arch magnets, but does not describe how to achieve the focusing effect.

[0003] In other words, existing magnet devices, when preparing magnets with a certain curvature, result in uneven magnetic field lines angles and residual magnetism in the curved magnets, and the magnets are prone to cracking and cannot be formed, and have high sound pressure levels. Utility Model Content

[0004] To overcome the problems in existing technologies where the molds used to prepare magnets with a certain curvature result in uneven magnetic field line angles and remanence, easy cracking and inability to form magnets, and high sound pressure levels, a forming device is provided. This device enables the obtained magnets to have more uniform magnetic field line angles θ and remanence Br, while reducing the cracking rate and sound pressure level.

[0005] The present invention solves the above-mentioned technical problems through the following technical solutions.

[0006] This utility model provides a forming device, which includes a first magnetic block and a second magnetic block; the first magnetic block includes multiple parallel magnetic blocks with different relative permeabilities arranged in a horizontal direction, and the bottom of the multiple magnetic blocks forms an arc-shaped groove; the second magnetic block includes multiple parallel magnetic blocks with different relative permeabilities arranged in a horizontal direction, and the top of the multiple magnetic blocks forms a semi-circular protrusion; the semi-circular protrusion is located in the space formed by the arc-shaped groove;

[0007] An arc-shaped mold cavity is provided between the arc-shaped groove and the semi-circular protrusion.

[0008] In this invention, preferably, the first magnetic block comprises 6-50 magnetic blocks, more preferably 10-50 magnetic blocks, for example, 30 magnetic blocks.

[0009] Preferably, the relative permeability of the magnetic blocks disposed on the axis of the first magnetic block is lower than the relative permeability of the magnetic blocks far from the axis of the first magnetic block.

[0010] Preferably, the relative permeability of the magnetic block increases in a gradient along the direction in which the axis of the first magnetic block extends to both ends.

[0011] Preferably, in the first magnetically conductive block, the difference in relative permeability between the magnetic blocks at adjacent ends is 40-333.

[0012] Preferably, the ratio of the relative permeability of the magnetic block located on the axis of the first magnetic block to the relative permeability of the magnetic block furthest from the axis of the first magnetic block is 1.05:1.3.

[0013] In this invention, preferably, the second magnetic block comprises 6-30 magnetic blocks, more preferably 10-50 magnetic blocks, for example, 20 or 30 magnetic blocks.

[0014] Preferably, the relative permeability of the magnetic blocks disposed on the axis of the second magnetic block is lower than the relative permeability of the magnetic blocks far from the axis of the second magnetic block.

[0015] Preferably, the relative permeability of the magnetic block increases in a gradient along the direction in which the axis of the second magnetic block extends to both ends.

[0016] Preferably, in the second magnetic block, the difference in relative permeability between adjacent magnetic blocks at both ends is 66-333.

[0017] Preferably, the ratio of the relative permeability of the magnetic block located on the axis of the second magnetic block to the relative permeability of the magnetic block furthest from the axis of the second magnetic block is 1.05:1.3.

[0018] In one specific embodiment, the relative permeability of the magnetic blocks disposed on the axis of the second magnetic block is 2000, and the relative permeability of the magnetic block farthest from the axis of the second magnetic block is 4000.

[0019] In this invention, preferably, the ratio of the radius of the semi-circular protrusion to the radius of the arc of the arc-shaped mold cavity on the side near the semi-circular protrusion is (0.8-0.95):1, and more preferably (0.8-0.9):1.

[0020] In this invention, preferably, the ratio of the radius of the arc-shaped groove to the radius of the arc on the side of the arc-shaped mold cavity closest to the arc-shaped groove is (0.85-0.95):1, for example, 0.9:1.

[0021] In this invention, preferably, the thickness of the gap formed between the arc-shaped groove and the semi-circular protrusion is greater than the thickness of the arc-shaped mold cavity.

[0022] Preferably, the thickness of the gap formed between the arc-shaped groove and the semi-circular protrusion is 5-20 mm, for example, 15 mm.

[0023] Preferably, the thickness of the arc-shaped mold cavity is 5-20mm, for example, 5mm.

[0024] In this invention, preferably, the arc of the arc-shaped mold cavity near the semi-circular protrusion and the vertical distance between the arc and the semi-circular protrusion are 3-10mm, for example, 5mm.

[0025] In this invention, preferably, the vertical distance between the arc of the arc-shaped mold cavity on the side close to the arc-shaped groove and the arc-shaped groove is 5-10mm, for example, 5mm.

[0026] In this invention, the arc-shaped mold cavity can be externally connected to a feeding mechanism, which is used to feed raw materials into the arc-shaped mold cavity.

[0027] In this invention, apart from the structure described above, all other spaces can be filled with non-magnetic magnets.

[0028] The positive and progressive effects of this utility model are as follows:

[0029] The molding device of this invention has a simple structure and is suitable for industrial production. When used to prepare magnets, the molding device can make the obtained magnets have more uniform magnetic field line angles θ and remanence Br. At the same time, it can reduce the cracking rate and sound pressure level. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the molding apparatus in Example 1.

[0031] The attached figures are labeled as follows:

[0032] 1-First magnetic conductive block; 2-Second magnetic conductive block; 3-Arc-shaped mold cavity. Detailed Implementation

[0033] The present invention is further illustrated below by way of embodiments, but these embodiments do not limit the present invention to the scope of the embodiments described. Experimental methods in the following embodiments that do not specify specific conditions are performed according to conventional methods and conditions, or as selected according to the product instructions.

[0034] Example 1

[0035] A schematic diagram of the molding device in this embodiment is shown below. Figure 1 As shown, it includes a first magnetic block 1 and a second magnetic block 2; the first magnetic block 1 includes multiple parallel magnetic blocks with different relative permeabilities arranged in the horizontal direction, and the bottom of the multiple magnetic blocks forms an arc-shaped groove; the second magnetic block 2 includes multiple parallel magnetic blocks with different relative permeabilities arranged in the horizontal direction, and the top of the multiple magnetic blocks forms a semi-circular protrusion; the semi-circular protrusion is located in the space formed by the arc-shaped groove;

[0036] An arc-shaped mold cavity 3 is provided between the arc-shaped groove and the semi-circular protrusion. The ratio of the radius of the semi-circular protrusion to the radius of the arc on the side of the arc-shaped mold cavity 3 closest to the semi-circular protrusion is 0.9:1.

[0037] The first magnetic block 1 includes 30 magnetic blocks; the ratio of the relative permeability of the magnetic blocks located on the axis of the first magnetic block 1 to the relative permeability of the magnetic blocks away from the axis of the first magnetic block 1 is 1.05:1.3; the relative permeability of the magnetic blocks increases in a gradient in the direction extending from the axis of the first magnetic block 1 to both ends, and the difference in relative permeability between adjacent magnetic blocks at both ends is 100;

[0038] The second magnetic block 2 includes 20 magnetic blocks; the ratio of the relative permeability of the magnetic blocks 2 located on the axis of the second magnetic block 2 to the relative permeability of the magnetic blocks away from the axis of the second magnetic block 2 is 1.05:1.3; the relative permeability of the magnetic blocks increases in a gradient in the direction extending from the axis of the second magnetic block 2 to both ends, and the difference in relative permeability between adjacent magnetic blocks at both ends is 120.

[0039] The ratio of the radius of the arc-shaped groove to the radius of the arc on the side of the arc-shaped mold cavity 3 closest to the arc-shaped groove is 0.9:1;

[0040] The thickness of the gap formed between the arc-shaped groove and the semi-circular protrusion is 15mm, the thickness of the arc-shaped mold cavity 3 is 5mm, the vertical distance between the arc on the side of the arc-shaped mold cavity 3 near the semi-circular protrusion and the semi-circular protrusion is 5mm, and the vertical distance between the arc on the side of the arc-shaped mold cavity 3 near the arc-shaped groove and the arc-shaped groove is 5mm.

[0041] In this embodiment, a feeding mechanism is connected to the external arc-shaped mold cavity 3. Figure 1 (Not shown in the image), the feeding mechanism is used to deliver raw materials to the arc-shaped mold cavity 3.

[0042] The relative permeability was tested using a closed-loop ring sample method, and the testing equipment was a BH loop meter / AC magnetic measurement system.

[0043] Example 2

[0044] In this embodiment, the ratio of the radius of the semi-circular protrusion to the radius of the arc-shaped mold cavity near the semi-circular protrusion is 0.8:1; the rest of the structure is the same as in Embodiment 1.

[0045] Example 3

[0046] In this embodiment, the ratio of the radius of the semi-circular protrusion to the radius of the arc-shaped mold cavity on the side near the semi-circular protrusion is 0.95:1; the rest of the structure is the same as in Embodiment 1.

[0047] Example 4

[0048] The first magnetic block of the molding device in this embodiment includes 6 magnetic blocks; the rest of the structure is the same as in embodiment 1.

[0049] Example 5

[0050] The first magnetic block of the molding device in this embodiment includes 50 magnetic blocks; the rest of the structure is the same as in embodiment 1.

[0051] Example 6

[0052] The second magnetic block of the molding device in this embodiment includes 6 magnetic blocks; the rest of the structure is the same as in embodiment 1.

[0053] Example 7

[0054] The second magnetic block of the molding device in this embodiment includes 30 magnetic blocks; the rest of the structure is the same as in embodiment 1.

[0055] Example 9

[0056] In this embodiment, the ratio of the radius of the semi-circular protrusion to the radius of the arc-shaped mold cavity on the side near the semi-circular protrusion is 0.75:1; the rest of the structure is the same as in Embodiment 1.

[0057] Example 10

[0058] In this embodiment, the ratio of the radius of the semi-circular protrusion to the radius of the arc-shaped mold cavity on the side closest to the semi-circular protrusion is 1:1; the rest of the structure is the same as in Embodiment 1.

[0059] Comparative Example 1

[0060] In the molding apparatus of this comparative example, the relative permeability of the multiple magnetic blocks in the first magnetic block is the same; the rest of the structure is the same as in Example 1.

[0061] Comparative Example 2

[0062] In the molding apparatus of this comparative example, the relative permeability of the multiple magnetic blocks in the second magnetic block is the same; the rest of the structure is the same as in Example 1.

[0063] Example 1

[0064] The magnets were prepared using the molding apparatus described in the above embodiments and comparative examples. The specific preparation steps are as follows:

[0065] The magnetic powder composition is as follows: PrNd: 29.5%; Al: 0.2%; Cu: 0.15%; Co: 0.4%; Ga: 0.2%; Zr: 0.18%; B: 0.95%, with the remainder being Fe.

[0066] The method for preparing a magnet includes the following steps:

[0067] 1. Take neodymium iron boron alloy sheets and add 0.1wt% lubricant (zinc stearate) to grind them into powder to obtain powder with a particle size distribution range of 3.0-3.9μm.

[0068] 2. Using the above-mentioned molding device, pressing is performed under a magnetic field of 2.0t and a molding pressure of 4-8MPa to obtain a density of 3.9g / cm³. 3 The blank; where, due to the influence of actual operation, the forming pressure here will fluctuate within a certain range.

[0069] 3. The pressed blank is sintered in a vacuum environment at 1080℃ to obtain the magnet.

[0070] The magnets prepared in the above embodiments and comparative examples were subjected to the following tests:

[0071] 1. Magnetic field B(θ): θ is the angle formed by any position on the arc of the circular magnet and the center line of the arc. θ can be specifically chosen as 0°, 5°, 10°, 20°, 30°, 40°, 50°, 55°, and 60°. max The maximum angle formed by the two ends of the arc and the center line of the arc is 30° in this application.

[0072] The surface magnetic field strength (i.e., the magnetic field strength of the surface) at different locations (different θ) is measured by a triaxial fluxmeter. Specifically, the obtained magnet is fixed on a graduated (360° scale) disk, and the fluxmeter probe is fixed to the surface of the magnet (at a certain distance from the surface of the magnet) using a clamp. The magnetic field strength at the corresponding location can be obtained by rotating the graduated disk, which is denoted as the surface magnetic field B(θ). (In actual testing, the magnet can also be fixed and the triaxial fluxmeter can be rotated.) The surface magnetic field at a position θ of 30° is defined as B0.

[0073] 2. Remanence Br: A small circular piece with a diameter of φ10*5mm was cut along the vertical direction of the arc for measurement, and tested using a NIM62000TB magnetic property measuring instrument.

[0074] 3. Crack ratio: Obtain multiple arc-shaped magnets using the above method. Observe the arc-shaped magnets visually using an industrial electronic magnifying glass. If a certain arc-shaped magnet has a crack, it is recorded as an arc-shaped magnet with a crack. Crack ratio = number of arc-shaped magnets with cracks / total number of arc-shaped magnets.

[0075] 4. Sound pressure level dB: Tested in a semi-anechoic chamber according to the standard "ISO 3745 / GB / T 10069.1", and the test equipment should be a Class 1 or Class 2 sound level meter conforming to the IEC 61672-1 standard.

[0076] The test results are listed in Tables 1 and 2:

[0077] Table 1

[0078]

[0079]

[0080] Table 2

[0081] Example 1 1.8％ 62 Example 2 1.6％ 61 Example 3 1.9％ 63 Example 4 3.9％ 66 Example 5 0.78％ 59 Example 6 3.6％ 65 Example 7 0.85％ 60 Example 8 1.9％ 63 Example 9 2.1％ 64 Comparative Example 1 6.5％ 69 Comparative Example 2 5.3％ 68

[0082] The results from the embodiments show that the cracking ratio can reach below 3.9% and the sound pressure level (SPL) below 66A, indicating that the molding apparatus provided by the embodiments of this utility model can obtain magnets with lower cracking ratios and SPLs. The results from the embodiments and comparative examples show that if the first magnetic block does not have multiple magnetic blocks with different relative permeabilities, or if the second magnetic block does not have multiple magnetic blocks with different relative permeabilities, the cracking ratio will be 5.3% or even 6.5%, and the SPL will be above 68A.

[0083] According to the results of the embodiments, the first magnetic block includes 10-50 magnetic blocks, the second magnetic block includes 10-50 magnetic blocks, and the ratio of the radius of the semi-circular protrusion to the radius of the arc of the arc-shaped cavity near the semi-circular protrusion is (0.8-0.9):1, which can further reduce the cracking rate to below 1.8% and reduce the sound pressure level to below 62A.

[0084] Meanwhile, the magnets prepared in the examples can satisfy the following formula:

[0085]

[0086] in,

[0087] B0 is the surface magnetic field at the center of the arc; θ is the angle formed by any position of the arc and the center line of the arc; B (θ) The magnetic field at position θ; θ max Let α be the angle formed by the two ends of the arc and the center line of the arc; α satisfies: 0.8≤|α|≤1. When α satisfies: 0.8≤|α|≤1, the calculated B(θ) and the B(θ) actually measured in Table 1 will have an error of no more than 0.01T. This error is within a reasonable range and its impact can be ignored.

[0088] However, the magnet prepared in the comparative model has |α| less than 0.8 at certain positions, which does not satisfy the above formula.

Claims

1. A molding apparatus, characterized in that, It includes a first magnetically conductive block and a second magnetically conductive block; the first magnetically conductive block includes multiple parallel magnetic segments with different relative permeabilities arranged in the horizontal direction, and the bottom of the multiple magnetic segments forms an arc-shaped groove; the second magnetically conductive block includes multiple parallel magnetic segments with different relative permeabilities arranged in the horizontal direction, and the top of the multiple magnetic segments forms a semi-circular protrusion; the semi-circular protrusion is located in the space formed by the arc-shaped groove; An arc-shaped mold cavity is provided between the arc-shaped groove and the semi-circular protrusion.

2. The molding apparatus as described in claim 1, characterized in that, It meets one or more of the following conditions: (a) The first magnetic block comprises 6-50 magnetic blocks; (b) The second magnetic block comprises 6-30 magnetic blocks.

3. The molding apparatus as described in claim 2, characterized in that, It meets one or more of the following conditions: (a) The relative permeability of the magnetic block disposed on the axis of the first magnetic block is lower than the relative permeability of the magnetic block far from the axis of the first magnetic block. (b) The relative permeability of the magnetic block disposed on the axis of the second magnetic block is lower than that of the magnetic block disposed away from the axis of the second magnetic block.

4. The molding apparatus as described in claim 3, characterized in that, It meets one or more of the following conditions: (a) In the direction in which the axis of the first magnetic block extends to both ends, the relative permeability of the magnetic block increases in a gradient; (b) In the direction in which the axis of the second magnetic block extends to both ends, the relative permeability of the magnetic block increases in a gradient.

5. The molding apparatus as described in claim 4, characterized in that, It meets one or more of the following conditions: (a) In the first magnetic block, the difference in relative permeability between adjacent magnetic blocks at both ends is 40-333; (b) In the second magnetic block, the difference in relative permeability between the magnetic blocks at adjacent ends is 66-333.

6. The molding apparatus as described in claim 3, characterized in that, It meets one or more of the following conditions: (a) The ratio of the relative permeability of the magnetic blocks disposed on the axis of the first magnetic block to the relative permeability of the magnetic blocks far from the axis of the first magnetic block is 1.05:1.3; (b) The ratio of the relative permeability of the magnetic block located on the axis of the second magnetic block to the relative permeability of the magnetic block located away from the axis of the second magnetic block is 1.05:1.

3.

7. The molding apparatus as described in claim 1, characterized in that, It meets one or more of the following conditions: (a) The ratio of the radius of the semi-circular protrusion to the radius of the arc of the arc-shaped mold cavity on the side closest to the semi-circular protrusion is (0.8-0.95):1; (b) The ratio of the radius of the arc-shaped groove to the radius of the arc on the side of the arc-shaped mold cavity closest to the arc-shaped groove is (0.85-0.95):

1.

8. The molding apparatus as described in claim 1, characterized in that, The thickness of the gap formed between the arc-shaped groove and the semi-circular protrusion is greater than the thickness of the arc-shaped mold cavity.

9. The molding apparatus as described in claim 8, characterized in that, It meets one or more of the following conditions: (a) The thickness of the gap formed between the arc-shaped groove and the semi-circular protrusion is 5-20 mm; (b) The thickness of the arc-shaped mold cavity is 5-20 mm.

10. The molding apparatus as claimed in claim 1, characterized in that, It meets one or more of the following conditions: (a) The vertical distance between the arc of the arc-shaped mold cavity on the side close to the semi-circular protrusion and the semi-circular protrusion is 3-10mm; (b) The vertical distance between the arc of the arc-shaped mold cavity on the side close to the arc-shaped groove and the arc-shaped groove is 5-10 mm.

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