A charging device, a charging method, and a press

Abstract

The application relates to a feeding device, a feeding method and a press. The feeding device comprises a box assembly, a plurality of feeding boxes arranged in sequence, each feeding box having a feeding cavity with two open ends, a baffle plate closing the bottom end opening of the feeding box, the baffle plate being provided with sieve holes, a vibrator arranged on the feeding box, an air inlet assembly movable relative to the feeding box, capable of closing the top end opening of the feeding box to deliver gas into the feeding cavity, a driving assembly for driving the movement of the box assembly, and a distributor arranged in the feeding cavity at the connection between the second conical part and the discharge part. The feeding device can uniformly distribute raw material powder in the mold cavity, improving the performance of the magnet.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of magnet preparation, in particular to a feeding device, a feeding method and a press. BACKGROUND

[0002] Neodymium iron boron is widely used in new energy vehicles, wind power generation, acoustic devices and other fields due to its excellent performance. With the development of technology, neodymium iron boron magnets are developing towards miniaturization. The preparation of conventional magnets requires the preparation of large blocks of magnets first, and then a large number of cutting and precision machining to meet the size requirements, resulting in high loss rate and high cost in the preparation process.

[0003] Near-net forming of magnets is a development direction of magnet processing and preparation, which directly prepares thin plate-shaped magnets using a mold, reducing the slicing process. However, for magnets with small thickness, the powder is difficult to uniformly distribute in each cavity of the mold when using mold near-net forming due to the friction between the powder and the mold cavity and the agglomeration of the powder. Due to the uneven distribution of the powder in the mold cavity, the internal stress of the magnet at different positions after pressing is different, and the performance of the magnet is unstable. SUMMARY

[0004] Based on the above problems, the present application provides a feeding device, a feeding method and a press, which realizes uniform feeding of the forming mold.

[0005] One embodiment of the present application provides a feeding device, comprising:

[0006] A hopper assembly comprising a plurality of feeding boxes arranged in sequence, each feeding box having an open-ended feeding cavity, and each feeding box comprising:

[0007] A feeding portion;

[0008] A first conical portion connected to the bottom end of the feeding portion, the horizontal cross-sectional area of the first conical portion gradually decreasing from top to bottom;

[0009] A first straight cylinder portion connected to the bottom end of the first conical portion;

[0010] A second conical portion connected to the bottom end of the first straight cylinder portion, the horizontal cross-sectional area of the second conical portion gradually increasing from top to bottom;

[0011] A discharging portion connected to the bottom end of the second conical portion;

[0012] A baffle plate closing the bottom end opening of the feeding box, the baffle plate being provided with a sieve hole;

[0013] A vibrator provided on the feeding box;

[0014] An air inlet assembly is movable relative to the feeding box to close the top opening of the feeding box to deliver air into the feeding cavity;

[0015] A driving assembly is configured to drive the feeding box assembly to move;

[0016] A distributor is arranged in the feeding cavity at the connection between the second conical part and the discharging part, and the distributor comprises:

[0017] A first distributor plate;

[0018] A second distributor plate is connected to the first distributor plate to form a pointed end, the pointed end is arranged upward, an included angle α between the first distributor plate and the second distributor plate is 30-70°, and an included angle β between the two inclined walls of the second conical part is greater than the included angle α.

[0019] According to some embodiments of the present application, the discharging part comprises:

[0020] A third conical part is connected to the bottom end of the second conical part, and the horizontal cross-sectional area of the third conical part gradually decreases from top to bottom;

[0021] A second straight cylinder part is connected to the bottom end of the third conical part.

[0022] According to some embodiments of the present application, the ratio of the length to the width of the feeding part is 2-5;

[0023] The ratio of the length to the width of the first straight cylinder part is 1.5-3;

[0024] The ratio of the length to the width of the second straight cylinder part is 3-6;

[0025] The ratio of the height of the first straight cylinder part to the height of the feeding box is 0.4-0.6.

[0026] According to some embodiments of the present application, the distance between the pointed end of the distributor and the bottom surface of the feeding box is 20-40 mm;

[0027] The distance between the top end of the second conical part and the bottom surface of the feeding box is 30-60 mm.

[0028] According to some embodiments of the present application, the screen holes of the blocking plate comprise rectangular holes, the length of the rectangular holes is 5-50 mm, the width of the rectangular holes is 1-3 mm, and the distance between adjacent rectangular holes is 2-6 mm.

[0029] According to some embodiments of the present application, the feeding device further comprises a weighing device, the weighing device is configured to weigh raw materials of a preset weight and deliver the raw materials to the feeding box.

[0030] According to some embodiments of the present application, the driving assembly comprises:

[0031] A first guide rail;

[0032] A first sliding block slidingly arranged on the first guide rail;

[0033] A second guide rail arranged on the first sliding block;

[0034] A second sliding block slidingly arranged on the second guide rail, and the material box assembly is connected to the second sliding block.

[0035] One embodiment of the present application provides a material feeding method using the material feeding device as described above, comprising:

[0036] Feeding raw material powder into the material feeding box, and the material blocking plate blocks the raw material powder from falling off;

[0037] The air inlet assembly seals the top opening of the material feeding box;

[0038] The driving assembly drives the material box assembly to move to a preset position;

[0039] Gas is introduced into the material feeding box, and the vibrator is started to make the raw material powder in the material feeding box fall through the sieve holes of the material blocking plate into the mold cavity.

[0040] According to some embodiments of the present application, the vibration frequency of the vibrator is 4000 r / min-10000 r / min, and the vibration time is 5-20 s.

[0041] According to some embodiments of the present application, the average particle size of the raw material powder is 3.5-5 um.

[0042] One embodiment of the present application provides a press machine with the material feeding device as described above.

[0043] The material feeding device of the present application first feeds raw material powder into the material feeding box, the material blocking plate can prevent the raw material powder in the material feeding box from falling off, the material box assembly moves above the mold, and the raw material powder is made to quickly fall through the sieve holes by gas pressure and vibration of the vibrator, so that the raw material powder can be uniformly distributed in the mold cavity, and the performance of the magnet is improved. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the present application, the drawings required in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to these drawings by those skilled in the art without exceeding the scope of the present application.

[0045] Figure 1 is a schematic diagram of the feeding device of the embodiment of the present application;

[0046] Figure 2 is a schematic diagram of the hopper assembly of the embodiment of the present application;

[0047] Figure 3 is a cross-sectional view of the hopper of the embodiment of the present application;

[0048] Figure 4 is a front view of the hopper of the embodiment of the present application;

[0049] Figure 5 is a schematic diagram of the material blocking plate of the embodiment of the present application;

[0050] Figure 6 is a schematic diagram of the material distributor of the embodiment of the present application Figure 1 ;

[0051] Figure 7 is a schematic diagram of the material distributor of the embodiment of the present application Figure 2 ;

[0052] Figure 8 is a schematic diagram of the hopper of the embodiment of the present application;

[0053] Figure 9 is a side view of the hopper of the embodiment of the present application;

[0054] Figure 10 is a schematic diagram of the included angle between the first material blocking plate and the second material blocking plate of the embodiment of the present application;

[0055] Figure 11 is a schematic diagram of the distance between the tip of the material distributor and the bottom surface of the hopper of the embodiment of the present application;

[0056] Figure 12 is a schematic diagram of the screen hole of the embodiment of the present application;

[0057] Figure 13 is a schematic diagram of the weighter of the embodiment of the present application;

[0058] Figure 14 is a schematic diagram of the driving assembly of the embodiment of the present application;

[0059] Figure 15 is a schematic diagram of the feeding of the weighter to the hopper assembly of the embodiment of the present application;

[0060] Figure 16 is a schematic diagram of the air inlet assembly of the embodiment of the present application;

[0061] Figure 17 is a schematic diagram of the feeding of the feeding device to the mold cavity of the embodiment of the present application. DETAILED DESCRIPTION

[0062] With reference to the drawings of the embodiments of the present application, the technical solutions of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0063] As shown in Figure 1 and Figure 6 , the embodiments of the present application provide a feeding device 100, which is used for feeding raw materials into a mold during the process of preparing a magnet. The feeding device 100 comprises a box assembly 1, a blocking plate 2, a vibrator 3, an air inlet assembly 4, a driving assembly 5 and a distributor 6.

[0064] As shown in Figure 4 , the blocking plate 2 is arranged at the bottom of the feeding box 11, and the blocking plate 2 seals the bottom opening of the feeding box 11. The blocking plate 2 is provided with sieve holes 21, and the blocking plate 2 prevents the raw materials from falling after entering the feeding cavity 11a. The size and number of the sieve holes 21 are set according to requirements. Figure 2 Figure 3 As shown in Figure 4 , the blocking plate 2 is arranged at the bottom of the feeding box 11, and the blocking plate 2 seals the bottom opening of the feeding box 11. The blocking plate 2 is provided with sieve holes 21, and the blocking plate 2 prevents the raw materials from falling after entering the feeding cavity 11a. The size and number of the sieve holes 21 are set according to requirements.

[0065] As shown in Figure 4 , the blocking plate 2 is arranged at the bottom of the feeding box 11, and the blocking plate 2 seals the bottom opening of the feeding box 11. The blocking plate 2 is provided with sieve holes 21, and the blocking plate 2 prevents the raw materials from falling after entering the feeding cavity 11a. The size and number of the sieve holes 21 are set according to requirements.

[0066] The feeding part 111 is located at the top end of the feeding box 11, and the feeding part 111 is in a straight cylindrical shape. The first tapered part 112 is connected to the bottom end of the feeding part 111, and the first tapered part 112 comprises two opposite inclined walls, and the horizontal cross-sectional area of the first tapered part 112 gradually decreases from top to bottom. The first straight cylinder part 113 is connected to the bottom end of the first tapered part 112. The second tapered part 114 is connected to the bottom end of the first straight cylinder part 113, and the second tapered part 114 comprises two opposite inclined walls, and the horizontal cross-sectional area of the second tapered part 114 gradually increases from top to bottom. The discharge part 115 is connected to the bottom end of the second tapered part 114.

[0067] As shown in Figure 5 , the blocking plate 2 is arranged at the bottom of the feeding box 11, and the blocking plate 2 seals the bottom opening of the feeding box 11. The blocking plate 2 is provided with sieve holes 21, and the blocking plate 2 prevents the raw materials from falling after entering the feeding cavity 11a. The size and number of the sieve holes 21 are set according to requirements.

[0068] The vibrator 3 is installed on the feeding box 11. Optionally, the vibrator 3 is an existing vibrator. The vibration generated by the vibrator 3 can cause the raw material in the feeding chamber 11a to fall through the screen hole 21. Multiple feeding boxes 11 can share one vibrator 3. The number of vibrators 3 is set according to the requirements.

[0069] An air inlet assembly 4 is located at the top of the feeding box 11, and can close the top opening of the feeding box 11. The air inlet assembly 4 is movable relative to the feeding box 11; for example, the air inlet assembly 4 is connected to the feeding box assembly 1 via a hinge, and the air inlet assembly 4 can be rotated open to feed material into the feeding box 11. When the air inlet assembly 4 is closed, it can deliver gas into the feeding chamber 11a. Introducing gas with a preset pressure facilitates the rapid passage of the raw material through the sieve holes 21 and its rapid entry into the mold cavity, reducing the impact of friction on the mold cavity sidewalls on the raw material and promoting uniform distribution of the raw material within the mold cavity. Optionally, the gas is an inert gas, such as nitrogen.

[0070] The drive assembly 5 is used to drive the material box assembly 1 to move so that the material box assembly 1 can move between the feeding position and the discharging position.

[0071] like Figure 6 and Figure 7 As shown, the distributor 6 is disposed in the feeding chamber 11a, located at the connection between the second conical portion 114 and the discharge portion 115. Raw material 200 enters the feeding chamber 11a through the feeding portion 111, and falls to the discharge portion 115 after passing sequentially through the first conical portion 112, the first cylindrical portion 113, and the second conical portion 114. The first conical portion 112 ensures a more uniform distribution of the raw material 200 in space. When the raw material 200 enters the discharge portion 115 from the second conical portion 114, some of the raw material 200 contacts the distributor 6. The distributor 6 improves the uniformity of the distribution of the raw material 200 on the horizontal plane, ensuring that the raw material 200 is evenly distributed at the bottom of the feeding chamber 11a, facilitating its subsequent even falling into the mold cavity.

[0072] like Figure 10 As shown, the distributor 6 includes a first distributor plate 61 and a second distributor plate 62. The side of the second distributor plate 62 is connected to the side of the first distributor plate 61 to form a tip. The tip of the distributor 6 is set upward. Part of the raw material falling from above contacts the distributor 6. The raw material falls evenly from both sides of the distributor 6 into the discharge section 115.

[0073] In some embodiments, the included angle α between the first distribution plate 61 and the second distribution plate 62 is 30-70°. If the included angle α is too small, it will affect the distribution effect; if the included angle α is too large, it will hinder the falling of raw materials. The included angle β between the two inclined walls of the second conical part is greater than the included angle α. It is beneficial that the included angle β is 5-10° larger than the included angle α, which is conducive to the uniform distribution of raw materials.

[0074] The working process of the feeding device 100 of the embodiment includes:

[0075] 1. Adding raw materials into the feeding box 11 at the feeding position, and the blocking plate 2 blocks the raw materials from falling;

[0076] 2. The air inlet assembly 4 rotates to close the top opening of the feeding box 11;

[0077] 3. The driving assembly 5 drives the feeding box assembly 1 to move to a preset position;

[0078] 4. The air inlet assembly 4 introduces gas into the feeding box 11, and the vibrator 3 is started at the same time. The raw materials in the feeding box quickly fall through the sieve holes of the blocking plate into the mold cavity.

[0079] The feeding device 100 of the embodiment makes the raw materials quickly fall through the sieve holes by the gas pressure and the vibration of the vibrator, avoids the agglomeration of the raw materials, and uniformly distributes the raw materials in the mold cavity through the blocking plate 2 as a sieve. The density of each position of the pressed blank after pressing is uniform. The sintered blank pressing height difference (maximum value minus minimum value) after sintering can be controlled to be less than or equal to 0.28 mm, the non-pressing width difference can be controlled to be less than or equal to 0.22 mm, and the magnetization length difference can be controlled to be less than or equal to 0.27 mm, which is conducive to improving the performance of the magnet.

[0080] As shown in Figure 8 , the discharging part 115 includes a third conical part 1151 and a second straight cylinder part 1152. The third conical part 1151 is connected to the bottom end of the second conical part 114, and the third conical part 1151 includes two opposite inclined walls. The horizontal cross-sectional area of the third conical part 1151 gradually decreases from top to bottom for guiding the raw material powder. The second straight cylinder part 1152 is connected to the bottom end of the third conical part 1151. The horizontal cross-section of the second straight cylinder part 1152 is adapted to the mold cavity.

[0081] As shown in Figure 4 and Figure 9 , in some embodiments, the ratio of the length L1 of the feeding part 111 to the width D1 is 2-5, for example, the length L1 of the feeding part 111 is 71 mm, and the width D1 of the feeding part 111 is 24 mm. The ratio of the length L2 of the first straight cylinder part 113 to the width D2 is 1.5-3, for example, the length L2 of the first straight cylinder part 113 is 38 mm, and the width D2 of the first straight cylinder part 113 is 24 mm. The ratio of the length L3 of the second straight cylinder part 1151 to the width D3 is 3-6, for example, the length L3 of the second straight cylinder part 1151 is 58 mm, and the width D3 of the second straight cylinder part 1151 is 12 mm.

[0082] The ratio of the height H1 of the first straight cylinder part 113 to the height H of the feeding box 11 is 0.4-0.6. For example, the height H1 of the first straight cylinder part 113 is 90 mm, and the height H of the feeding box 11 is 200 mm. The size ratio of each part of the feeding box matches each other, which is conducive to the uniform distribution of the raw materials.

[0083] As shown in Figure 11 some embodiments, the distance H2 between the tip of the distributor 6 and the bottom surface of the feeding box 11 is 20-40 mm, for example, H2 is 32 mm. The distance H3 between the top end of the second tapered part 114 and the bottom surface of the feeding box 11 is 30-60 mm, for example, H3 is 50 mm.

[0084] As shown in Figure 12 some embodiments, the screen holes 21 of the blocking plate are rectangular holes, and each column of rectangular holes corresponds to one feeding box 11. The length of the rectangular hole is 5-50 mm, the width is 1-3 mm, and the distance between adjacent rectangular holes in each column is 2-6 mm. Compared with round holes or square holes, the rectangular holes have a faster discharging speed and better uniformity of raw materials.

[0085] As shown in Figure 13 some embodiments, the feeding device 100 further comprises a weighing device 7, which is used to weigh a predetermined amount of raw materials and convey the raw materials into the feeding box 11 through the top opening of the feeding box 11. The weighing device 7 can be an existing weighing device, for example, the weighing device 7 is a feeding hopper. The number of weighing devices 7 is set according to the requirements.

[0086] As shown in Figure 14 some embodiments, the driving assembly 5 comprises a first guide rail 51, a first sliding block 52, a second guide rail 53, and a second sliding block 54. The first guide rail 51 extends in the horizontal direction, and the first sliding block 52 is slidingly arranged on the first guide rail 51. Optionally, a first driver is used to drive the first sliding block 52 to slide, for example, the first driver is a motor. The second guide rail 53 is arranged on the first sliding block 52 and extends in the vertical direction. The second sliding block 54 is slidingly arranged on the second guide rail 53. Optionally, a second driver is used to drive the second sliding block 54, for example, the second driver is a motor. The feeding box assembly 1 is connected to the second sliding block 54. During feeding, the feeding box assembly 1 moves in the horizontal direction to above the mold, and the feeding box assembly 1 is lowered to a gap of 1-10 mm between the blocking plate 2 and the mold, so as to feed the raw materials into the mold cavity.

[0087] Embodiments of the present application provide a method for feeding using the above-mentioned feeding device 100, which comprises the following steps:

[0088] S1, raw material powder 200 is added to the feeding box 11, and the blocking plate 2 blocks the raw material powder 200 from falling.

[0089] AsFigure 15 As shown, for example, the number of weighers 7 is two, and the number of feeding boxes 11 is six. After the two weighers 7 weigh the raw material powder, the raw material powder is added into the first feeding box and the fourth feeding box, respectively.

[0090] The two weighers 7 weigh the raw material powder again, the feeding box assembly 1 moves to the left, and the two weighers 7 add the raw material powder into the second feeding box and the fifth feeding box, respectively.

[0091] The two weighers 7 weigh the raw material powder again, the feeding box assembly 1 moves to the left, and the two weighers 7 add the raw material powder into the second feeding box and the fifth feeding box, respectively.

[0092] S2, as shown in Figure 16 The air inlet assembly 4 seals the top opening of the feeding box 11.

[0093] S3, the driving assembly 5 drives the feeding box assembly 1 to move to a preset position, and the feeding box assembly 1 is located above the mold.

[0094] S4, as shown in Figure 17 The air inlet assembly 4 introduces gas into the feeding box 11, and the gas can be nitrogen. At the same time, the vibrator 3 is started, and the raw material powder 200 in the feeding box 11 falls through the sieve holes of the blocking plate 2 into the mold cavity of the mold 300. Optionally, the gas pressure is 0.01-0.05 MPa.

[0095] In some embodiments, the vibration frequency of the vibrator 3 is 4000-10000 r / min, and the vibration time is 5-20 s.

[0096] In some embodiments, the average particle size of the raw material powder 200 is 3.5-5 um.

[0097] Example 1

[0098] The number of feeding boxes 11 of the feeding device 100 is six, corresponding to the six mold cavities of the mold. The length L1 of the feeding part 111 is 71 mm, and the width D1 of the feeding part 111 is 24 mm. The length L2 of the first straight cylinder part 113 is 38 mm, and the width D2 of the first straight cylinder part 113 is 24 mm. The length L3 of the second straight cylinder part 1151 is 58 mm, and the width D3 of the second straight cylinder part 1151 is 12 mm. The height H1 of the first straight cylinder part 113 is 90 mm, and the height H of the feeding box 11 is 200 mm. The angle a between the first blocking plate 61 and the second blocking plate 62 is 60°, and the angle β between the two inclined walls of the second tapered part is 65°. The distance H2 between the tip of the distributor 6 and the bottom surface of the feeding box 11 is 32 mm, and the distance H3 between the top end of the second tapered part 114 and the bottom surface of the feeding box 11 is 50 mm.

[0099] The screen holes 21 of the baffle plate are oblong holes, the length of the oblong holes is 11 mm, the width is 1 mm, and the spacing between adjacent oblong holes in each column is 2 mm.

[0100] The raw material powder weight of a single cavity is 225.9 grams; the cavity size is 19.2 (non-pressing direction) x 43.7 (pressing direction) x 64.2 (magnetization direction); the cavity is filled using the above-described feeding device 100:

[0101] 1. The raw material powder 200 is added to the feeding box 11, and the baffle plate 2 blocks the raw material powder 200 from falling.

[0102] 2. The air inlet assembly 4 seals the top opening of the feeding box 11.

[0103] 3. The driving assembly 5 drives the feeding box assembly 1 to move to a predetermined position, and the feeding box assembly 1 is located above the mold.

[0104] 4. The air inlet assembly 4 introduces nitrogen into the feeding box 11, and simultaneously starts the vibrator 3. The raw material powder 200 in the feeding box 11 falls through the screen holes of the baffle plate 2 into the cavity of the mold 300. The vibration frequency of the vibrator 3 is 6000 r / min, the vibration time is 10 s, and the gas pressure is 0.03 Mpa.

[0105] After the feeding device fills the powder into the cavity, the single block green compact is pressed with a density of 4.2 g / cm 3 , and the weight error is controlled within ±0.8 grams. After isostatic pressing of the pressed compact, the sintering furnace is used for sintering and aging treatment to obtain a neodymium iron boron blank. The blank size is 16.5 mm (non-pressing direction) x 38.5 mm (pressing direction) x 47.1 mm (magnetization direction). The density of the center and the corner of the blank is tested, and the average density value is calculated. The results are shown in Table 1.

[0106] After sintering and aging, the height difference (maximum value minus minimum value) of the pressing direction of 100 sintered blanks is 0.23 mm; the width difference of the non-pressing direction is 0.16 mm; and the length difference of the magnetization direction is 0.17 mm.

[0107] Comparative Example 1

[0108] The number of feeding boxes 11 of the feeding device 100 is six, corresponding to the six cavities of the mold. The length L1 of the feeding part 111 is 71 mm, and the width D1 of the feeding part 111 is 24 mm. The length L2 of the first straight cylinder part 113 is 38 mm, and the width D2 of the first straight cylinder part 113 is 24 mm. The length L3 of the second straight cylinder part 1151 is 58 mm, and the width D3 of the second straight cylinder part 1151 is 12 mm. The height H1 of the first straight cylinder part 113 is 90 mm, and the height H of the feeding box 11 is 200 mm. Different from Example 1, no distributor is provided.

[0109] The screen holes 21 of the baffle plate are oblong holes, the length of the oblong holes is 11 mm, the width is 1 mm, and the spacing between adjacent oblong holes in each column is 2 mm.

[0110] The weight of the raw material powder in a single cavity is 225.9 grams; the cavity size is 19.2 (non-pressing direction) x 43.7 (pressing direction) x 64.2 (magnetization direction).

[0111] The cavity is charged using the above-mentioned charging device 100:

[0112] 1. The raw material powder 200 is added to the charging box 11, and the baffle plate 2 blocks the raw material powder 200 from falling.

[0113] 2. The air inlet assembly 4 seals the top opening of the charging box 11.

[0114] 3. The drive assembly 5 drives the charging box assembly 1 to move to the preset position, and the charging box assembly 1 is located above the mold.

[0115] 4. The air inlet assembly 4 introduces nitrogen into the charging box 11, and at the same time, the vibrator 3 is started. The raw material powder 200 in the charging box 11 falls through the screen holes of the baffle plate 2 into the cavity of the mold 300. The vibration frequency of the vibrator 3 is 6000 r / min, the vibration time is 10 s, and the gas pressure is 0.03 Mpa.

[0116] After the charging device charges the powder into the cavity, the single piece of pressed blank has a weight error of 0.8 grams. After the pressed blank is isostatic pressed, it is placed in a sintering furnace, aged, and a neodymium iron boron blank is obtained. The blank size is 16.5 mm (non-pressing direction) x 38.5 mm (pressing direction) x 47.1 mm (magnetization direction). The density of the center and the corner of the blank is tested, and the average density value is calculated. The results are shown in Table 1.

[0117] After sintering and aging, the pressing direction height difference (maximum value minus minimum value) of 100 sintered blanks is 0.53 mm; the non-pressing direction width difference is 0.44 mm; and the magnetization direction length difference is 0.51 mm.

[0118] Comparative Example 2

[0119] The number of the feeding boxes 11 of the feeding device 100 is six, which correspond to six cavities of the mold. The length L1 of the feeding part 111 is 71 mm, and the width D1 of the feeding part 111 is 24 mm. The length L2 of the first straight cylinder part 113 is 38 mm, and the width D2 of the first straight cylinder part 113 is 24 mm. The length L3 of the second straight cylinder part 1151 is 58 mm, and the width D3 of the second straight cylinder part 1151 is 12 mm. The height H1 of the first straight cylinder part 113 is 90 mm, and the height H of the feeding box 11 is 200 mm. Different from the embodiment 1, the angle of the included angle a between the first distribution plate 61 and the second distribution plate 62 of the distributor is 75°, and the angle of the included angle b between the two inclined walls of the second tapered part is 90°. The distance H2 between the tip of the distributor 6 and the bottom surface of the feeding box 11 is 32 mm, and the distance H3 between the top end of the second tapered part 114 and the bottom surface of the feeding box 11 is 50 mm.

[0120] The screen hole 21 of the blocking plate is a rectangular hole, the length of the rectangular hole is 11 mm, the width is 1 mm, and the distance between adjacent rectangular holes in each column is 2 mm.

[0121] The weight of the raw material powder in a single cavity is 225.9 grams, and the cavity size is 19.2 (non-pressing direction) x 43.7 (pressing direction) x 64.2 (magnetization direction).

[0122] The feeding device 100 is used to feed the cavities:

[0123] 1. The raw material powder 200 is added to the feeding box 11, and the blocking plate 2 blocks the raw material powder 200 from falling.

[0124] 2. The air inlet assembly 4 seals the top opening of the feeding box 11.

[0125] 3. The driving assembly 5 drives the feeding box assembly 1 to move to a predetermined position, and the feeding box assembly 1 is located above the mold.

[0126] 4. The air inlet assembly 4 introduces nitrogen into the feeding box 11, and the vibrator 3 is started at the same time. The raw material powder 200 in the feeding box 11 falls through the screen hole of the blocking plate 2 into the cavity of the mold 300. The vibration frequency of the vibrator 3 is 6000 r / min, the vibration time is 10 s, and the gas pressure is 0.03 Mpa.

[0127] After the feeding device feeds the cavities, the mold is pressed, and the weight error of a single green compact is controlled within ±0.8 grams. After the pressed compact is isostatic pressed, it is placed in a sintering furnace for sintering and aging treatment, and a neodymium iron boron blank is obtained. The blank size is 16.5 mm (non-pressing direction) x 38.5 mm (pressing direction) x 47.1 mm (magnetization direction). The densities of the center and the corner of the blank are tested, and the average density value is calculated. The results are shown in Table 1.

[0128] After sintering and aging, the pressing height difference (maximum value minus minimum value) of 100 sintered blanks is 0.49 mm; the non-pressing width difference is 0.42 mm; and the magnetization length difference is 0.48 mm.

[0129] Comparative Example 3

[0130] The number of the feeding boxes 11 of the feeding device 100 is six, corresponding to the six cavities of the mold. The length L1 of the feeding part 111 is 71 mm, and the width D1 of the feeding part 111 is 24 mm. The length L2 of the first straight cylinder part 113 is 38 mm, and the width D2 of the first straight cylinder part 113 is 24 mm. The length L3 of the second straight cylinder part 1151 is 58 mm, and the width D3 of the second straight cylinder part 1151 is 12 mm. The height H1 of the first straight cylinder part 113 is 90 mm, and the height H of the feeding box 11 is 200 mm. The angle of the included angle a between the first distribution plate 61 and the second distribution plate 62 is 60°, and the angle of the included angle b between the two inclined walls of the second tapered part is 65°. The distance H2 between the tip of the distributor 6 and the bottom surface of the feeding box 11 is 32 mm, and the distance H3 between the top end of the second tapered part 114 and the bottom surface of the feeding box 11 is 50 mm.

[0131] Different from Example 1, the screen holes 21 of the blocking plate are rectangular holes, the length of the rectangular hole is 4 mm, the width is 0.8 mm, and the distance between adjacent rectangular holes in each column is 1 mm.

[0132] The weight of the raw material powder in a single cavity is 225.9 grams, and the cavity size is 19.2 (non-pressing direction) x 43.7 (pressing direction) x 64.2 (magnetization direction);

[0133] The feeding device 100 is used to feed the cavities:

[0134] 1. The raw material powder 200 is added to the feeding box 11, and the blocking plate 2 blocks the raw material powder 200 from falling.

[0135] 2. The air inlet assembly 4 seals the top opening of the feeding box 11.

[0136] 3. The driving assembly 5 drives the feeding box assembly 1 to move to a predetermined position, and the feeding box assembly 1 is located above the mold.

[0137] 4. The air inlet assembly 4 introduces nitrogen into the feeding box 11, and at the same time, the vibrator 3 is started, and the raw material powder 200 in the feeding box 11 falls through the screen holes of the blocking plate 2 into the cavities of the mold 300. The vibration frequency of the vibrator 3 is 6000 r / min, the vibration time is 10 s, and the gas pressure is 0.03 Mpa.

[0138] The powder is added to the mold cavity by the feeding device, and the weight error of the single block compacted blank is controlled within ±0.8 g. After isostatic pressing of the compacted blank, the sintering and aging treatment is performed in the sintering furnace to obtain the Nd-Fe-B blank. The size of the blank is 16.5 mm (non-pressing direction) x 38.5 mm (pressing direction) x 47.1 mm (magnetization direction). The densities of the center and the corner of the blank are tested, and the average density value is calculated. The results are shown in Table 1.

[0139] After sintering and aging, the height difference (maximum value minus minimum value) of the 100 sintered blanks in the pressing direction is 0.51 mm; the width difference in the non-pressing direction is 0.41 mm; and the length difference in the magnetization direction is 0.52 mm.

[0140] Comparative Example 4

[0141] The number of feeding boxes 11 of the feeding device 100 is six, corresponding to the six mold cavities of the mold. Different from Example 1, the length L1 of the feeding part 111 is 35 mm, the width D1 of the feeding part 111 is 20 mm; the length L2 of the first straight cylinder part 113 is 30 mm, the width D2 of the first straight cylinder part 113 is 20 mm; the length L3 of the second straight cylinder part 1151 is 25 mm, the width D3 of the second straight cylinder part 1151 is 10 mm; the height H1 of the first straight cylinder part 113 is 60 mm, and the height H of the feeding box 11 is 200 mm. The angle α between the first and second distribution plates 61 and 62 is 60°, and the angle β between the two inclined walls of the second tapered part is 65°. The distance H2 between the tip of the distributor 6 and the bottom surface of the feeding box 11 is 42 mm, and the distance H3 between the top end of the second tapered part 114 and the bottom surface of the feeding box 11 is 60 mm.

[0142] The screen holes 21 of the blocking plate are rectangular holes with a length of 11 mm and a width of 1 mm. The distance between adjacent rectangular holes in each column is 2 mm.

[0143] The weight of the raw material powder in a single mold cavity is 225.9 g, and the size of the mold cavity is 19.2 (non-pressing direction) x 43.7 (pressing direction) x 64.2 (magnetization direction).

[0144] The feeding device 100 is used to feed the mold cavity:

[0145] 1. The raw material powder 200 is added to the feeding box 11, and the blocking plate 2 blocks the raw material powder 200 from falling.

[0146] 2. The air inlet assembly 4 seals the top opening of the feeding box 11.

[0147] 3. The driving assembly 5 drives the feeding box assembly 1 to move to the preset position, and the feeding box assembly 1 is located above the mold.

[0148] 4. Nitrogen gas is introduced into the feeding box 11 by the air intake component 4, and the vibrator 3 is started at the same time. The raw material powder 200 in the feeding box 11 falls into the mold cavity of the mold 300 through the sieve holes of the baffle plate 2. The vibration frequency of the vibrator 3 is 6000 r / min, the vibration time is 10s, and the gas pressure is 0.03Mpa.

[0149] After the powder is added to the mold cavity by the feeding device, it is pressed. The weight error of a single pressed blank is controlled within ±0.8 grams. The pressed blank is isostatically pressed and then placed in a sintering furnace for sintering and aging treatment to obtain a NdFeB blank with dimensions of 16.5mm (non-pressing direction) × 38.5mm (pressing direction) × 47.1mm (magnetizing direction). The density at the center and corners of the blank is tested, and the average density value is calculated. The results are shown in Table 1.

[0150] After sintering and aging, the height difference (maximum value minus minimum value) in the pressing direction of 100 sintered blanks is 0.48 mm; the width difference in the non-pressing direction is 0.41 mm; and the length difference in the magnetization direction is 0.47 mm.

[0151] Table 1

[0152] Average density g / cm 3 (central) Average density g / cm 3 (corner) Example 1 7.56 7.55 Comparative Example 1 7.55 7.49 Comparative Example 2 7.55 7.50 Comparative Example 3 7.55 7.47 Comparative Example 4 7.56 7.49

[0153] As can be seen from the comparative examples and comparative embodiments, the feeding device of this application solves the technical problem of uneven filling at the corners of the mold cavity, so that the density at the corners of the blank is consistent with the density at the center.

[0154] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are only for the purpose of helping to understand the technical solutions and core ideas of this application. Therefore, any changes or modifications made by those skilled in the art based on the ideas of this application, and on the specific implementation methods and application scope of this application, are all within the scope of protection of this application. In summary, the content of this specification should not be construed as a limitation of this application.

Claims

1. A charging device, characterized by, The application relates to a material box assembly and a material feeding device. The material box assembly comprises a plurality of material feeding boxes arranged in sequence, each of the material feeding boxes has a material feeding cavity with two open ends, and each of the material feeding boxes comprises: a feeding part; a first conical part connected to the bottom end of the feeding part, the horizontal cross-sectional area of the first conical part gradually decreases from top to bottom; a first straight cylinder part connected to the bottom end of the first conical part; a second conical part connected to the bottom end of the first straight cylinder part, the horizontal cross-sectional area of the second conical part gradually increases from top to bottom; a discharging part comprising: a third conical part connected to the bottom end of the second conical part, the horizontal cross-sectional area of the third conical part gradually decreases from top to bottom; a second straight cylinder part connected to the bottom end of the third conical part; a material blocking plate for closing the bottom end opening of the material feeding cavity, the material blocking plate is provided with sieve holes; a vibrator arranged on the material feeding cavity; an air inlet assembly which is movable relative to the material feeding cavity so as to close the top end opening of the material feeding cavity and to feed gas into the material feeding cavity; a driving assembly for driving the material box assembly to move; a material distributor arranged in the material feeding cavity at the joint between the second conical part and the discharging part, the material distributor comprises: a first material distribution plate; a second material distribution plate connected to the first material distribution plate to form a pointed end, the pointed end is arranged upward, the included angle alpha between the first material distribution plate and the second material distribution plate is 30-70 DEG, and the included angle beta between the two inclined walls of the second conical part is 5-10 DEG larger than the included angle alpha; wherein the length-width ratio of the feeding part is 2-5; the length-width ratio of the first straight cylinder part is 1.5-3; the length-width ratio of the second straight cylinder part is 3-6; the height-height ratio of the first straight cylinder part to the material feeding cavity is 0.4-0.6; the sieve holes of the material blocking plate comprise rectangular holes, the length of the rectangular holes is 5-50 mm, the width is 1-3 mm, and the spacing between adjacent rectangular holes is 2-6 mm.

2. The charging device according to claim 1, characterized in that the distance between the pointed end of the material distributor and the bottom surface of the material feeding cavity is 20-40 mm; the distance between the top end of the second conical part and the bottom surface of the material feeding cavity is 30-60 mm.

3. The charging device of claim 1, wherein The material feeding device further comprises a weighing device for weighing raw materials of a preset weight and feeding the raw materials into the material feeding cavity.

4. The charging device of claim 1, wherein The driving assembly comprises: a first guide rail; a first sliding block slidingly arranged on the first guide rail; a second guide rail arranged on the first sliding block; a second sliding block slidingly arranged on the second guide rail, and the material box assembly is connected to the second sliding block.

5. A method of feeding using the feeding device according to any one of claims 1 to 4, characterized in that, The method comprises the following steps: adding raw material powder into the material feeding cavity, and blocking the raw material powder from falling off by the material blocking plate; closing the top end opening of the material feeding cavity by the air inlet assembly; driving the material box assembly to move to a preset position by the driving assembly; feeding gas into the material feeding cavity, and starting the vibrator to make the raw material powder in the material feeding cavity fall into a mold cavity through the sieve holes of the material blocking plate.

6. The method of claim 5, wherein, The vibration frequency of the vibrator is 4000 r / min-10000 r / min, and the vibration time is 5-20 s.

7. The method of claim 5, wherein, The average particle size of the raw material powder is 3.5-5 um.

8. A press, characterized in that A charging device as claimed in any one of claims 1-4.

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