A NdFeB powder ball mill cavity assembly based on cavity diameter-varying gradient grinding

Abstract

The present invention relates to the technical field of NdFeB powder ball milling, and discloses a NdFeB powder ball mill cavity assembly based on cavity variable diameter gradient grinding, comprising a grinding portion, wherein the grinding portion comprises a fixed seat, and the fixed seat is rotatably connected to a ball mill barrel via a bearing seat arranged on its upper surface. The NdFeB powder ball mill cavity assembly based on cavity variable diameter gradient grinding can effectively solve the problem in the prior art that the grinding requirements of NdFeB powder at different stages during ball milling are different. In the initial stage, a large impact force is required to crush larger particles of raw materials, while as the grinding proceeds, a gentle and fine grinding action is required to avoid excessive grinding leading to particle agglomeration or destruction of the crystal structure, which affects the magnetic properties of the NdFeB powder. However, the existing ball mills usually adopt a single grinding mode, which cannot automatically adjust the grinding force and method according to the change of the material particle size, and it is difficult to achieve a gradient change from coarse grinding to fine grinding.

Description

Technical Field

[0001] The invention relates to the technical field of NdFeB powder ball milling, and in particular to a NdFeB powder ball milling cavity component based on cavity diameter-varying gradient grinding. Background Art

[0002] As an important magnetic material, NdFeB powder is widely used in modern industry. Ball mill is a common equipment for grinding NdFeB powder. The purpose of ball milling is to refine the raw material particles to a suitable particle size range. The ball mill mainly drives the grinding medium to impact and grind the material through the rotation of the cylinder, so that the material particle size is gradually reduced to meet the requirements of subsequent production processes.

[0003] In the existing technology, the grinding requirements of NdFeB powder are different at different stages during ball milling. In the initial stage, a large impact force is required to crush larger particles of raw materials. As the grinding progresses, a gentle and fine grinding action is required to avoid excessive grinding that causes particle agglomeration or crystal structure destruction, affecting the magnetic properties of NdFeB powder. However, existing ball mills usually adopt a single grinding mode and cannot automatically adjust the grinding force and method according to changes in material particle size, making it difficult to achieve a gradient change from coarse grinding to fine grinding. Summary of the Invention

[0004] In response to the above-mentioned shortcomings of the prior art, the present invention provides a NdFeB powder ball mill cavity assembly based on cavity diameter variable gradient grinding, which can effectively solve the problem in the prior art that the grinding requirements of NdFeB powder are different at different stages during ball milling. In the initial stage, a larger impact force is required to crush larger particles of raw materials, and as the grinding proceeds, a gentler and finer grinding action is required to avoid excessive grinding leading to particle agglomeration or destruction of the crystal structure, which affects the magnetic properties of the NdFeB powder. However, the existing ball mills usually adopt a single grinding mode and cannot automatically adjust the grinding force and method according to changes in the material particle size, making it difficult to achieve a gradient change from coarse grinding to fine grinding.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0006] The present invention provides a NdFeB powder ball mill cavity assembly based on cavity diameter-varying gradient grinding, comprising:

[0007] The grinding part includes a fixed seat, the fixed seat is rotatably connected to a ball mill through a bearing seat provided on the upper surface of the fixed seat, and one end of the ball mill is fixedly connected to a feed port;

[0008] A discharge portion, the discharge portion comprising a support frame fixed to the upper surface of a fixed seat, the upper surface of the support frame being fixedly connected to a discharge plate, one side of the discharge plate extending into the interior of the ball mill and fixedly connected to a fixed plate rotatably connected to the outer surface of the rear partition, the circumferential outer surface of the fixed plate being in contact with the inner wall surface of the ball mill, a discharge piece being provided on the side of the fixed plate away from the rear partition, and the outer surface of the support frame being fixedly connected to a support cylinder in contact with the inner wall of the ball mill;

[0009] Among them, a cylinder is provided at the axis center of the middle part of the ball mill, and a front partition fixedly connected to the inner wall of the circumference of the ball mill is provided at the end of the cylinder close to the feed port, and a rear partition fixed to the inner wall of the circumference of the ball mill is provided at the end of the cylinder away from the front partition.

[0010] Furthermore, a placement groove is provided on the circumferential outer surface of the cylinder, and the placement groove is rotatably connected to a toggle plate via a shaft provided on the inner wall surface thereof, and a side of the placement groove away from the shaft adopts a bevel design.

[0011] Furthermore, the outer surface of the toggle plate adopts a cambered design, and the toggle plate is provided in plurality and distributed in a circular array with the cylinder as the center.

[0012] Furthermore, the blanking part, the side of the fixed plate away from the rear partition is rotatably connected to an eccentric cylinder, the end of the eccentric cylinder away from the fixed plate is nested in the outer surface of the support cylinder, the interior of the eccentric cylinder is provided with sieve holes, the left side of the eccentric cylinder is farthest away from the inner wall surface of the ball mill, and the interior of the eccentric cylinder is provided with a cleaning part that can be used to clean the sieve holes.

[0013] Furthermore, a notch is opened inside the eccentric cylinder, and the ball mill is provided with a support plate through a groove body opened on its circumferential inner surface. The outer surface of the support plate fits with the inner wall surface of the notch, and two support plates are provided and distributed in a circular array inside the ball mill.

[0014] Furthermore, the cleaning member includes a fixed frame, one side of the fixed frame is fixedly connected to the side of the fixed plate close to the support plate, the fixed frame is connected to a connecting plate through an elastic member arranged on the side close to the axis of the eccentric cylinder, and the middle part of the connecting plate close to the elastic member is fixedly connected to a through column that fits the inner wall surface of the sieve hole.

[0015] Furthermore, the outer surface of the fixed frame is rotatably connected to an eccentric roller that fits with the side of the connecting plate away from the through-column, the outer end of the eccentric roller is fixedly connected to a gear, the side of the gear away from the eccentric roller is rotatably connected to the outer surface of the support tube, and the inner wall surface of the eccentric tube is fixedly connected to a gear ring that meshes with the outer surface of the gear.

[0016] Furthermore, the outer end of the through-column is designed with a conical surface, a through hole is provided on a side of the support plate close to the through-column, and a grate hole is provided inside the fixing plate.

[0017] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0018] The present invention is provided with a ball mill, a front partition, a rear partition, a column and a discharge piece. The ball mill is divided into three chambers: a coarse crushing chamber, a fine grinding chamber and a discharge chamber. In the coarse crushing chamber, the impact force of the high-speed falling grinding balls is used to quickly crush the blocky NdFeB alloy ingot; in the fine grinding chamber, the rotation of the column drives the toggle plate to periodically flip the material, so that the flaky material is evenly stressed, solving the problem of excessive edge grinding and insufficient center grinding in traditional ball mills; in the discharge chamber, the eccentric cylinder and the inner wall of the ball mill form a crescent-shaped gap, and the material is flipped by the support plate to realize the cyclic process of screening, extrusion and re-screening, ensuring that only NdFeB particles with particle size that meets the requirements pass through the sieve hole, thereby improving the qualified rate of the discharge. The three chambers can realize graded grinding of the material, and realize gradient grinding from the coarse grinding area to the fine grinding area, with a small deviation in the average particle size distribution and a shortened grinding time, which is conducive to improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive effort.

[0020] Figure 1 A schematic diagram of the three-dimensional structure of an embodiment of the present invention;

[0021] Figure 2 Schematic diagram of the cross-sectional structure of a ball mill according to an embodiment of the present invention;

[0022] Figure 3 This is a schematic structural diagram of the front baffle, column, rear baffle, fixed plate, eccentric cylinder and support cylinder according to an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the separation structure of the rear partition plate and the fixed plate according to an embodiment of the present invention;

[0024] Figure 5 Schematic diagram of the cross-sectional structure of the column and the toggle plate according to an embodiment of the present invention;

[0025] Figure 6 Schematic diagram of the cross-sectional structure of the ball mill and the support plate according to an embodiment of the present invention;

[0026] Figure 7 For the embodiment of the present invention Figure 6 A schematic diagram of the partially enlarged structure at center A;

[0027] Figure 8 This is a schematic diagram of the separation structure of the discharge portion of an embodiment of the present invention;

[0028] Figure 9 Schematic diagram of the structure of the cleaning element according to an embodiment of the present invention.

[0029] The numbers in the figure represent: 1. Grinding part; 11. Fixed seat; 12. Bearing seat; 13. Ball mill; 130. Feed port; 14. Cylinder; 141. Placement groove; 142. Toggle plate; 15. Front partition; 151. Rear partition; 2. Discharge part; 21. Support frame; 22. Discharge plate; 23. Fixed plate; 231. Grate hole; 24. Discharge part; 241. Eccentric cylinder; 2411. Sieve hole; 2412. Notch; 242. Support plate; 25. Support cylinder; 26. Cleaning part; 261. Fixed frame; 262. Elastic part; 263. Connecting plate; 264. Through column; 265. Eccentric roller; 266. Gear; 267. Gear ring. DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0031] The present invention will be further described below with reference to the embodiments.

[0032] Example:

[0033] See also Figures 1-9 The present invention provides a technical solution: a NdFeB powder ball mill cavity assembly based on cavity diameter gradient grinding, comprising:

[0034] The grinding part 1 includes a fixed base 11, which is rotatably connected to a ball mill 13 via a bearing base 12 provided on its upper surface. One end of the ball mill 13 is fixedly connected to a feed port 130.

[0035] The discharge section 2 includes a support frame 21 fixed to the upper surface of the fixed seat 11, and a discharge plate 22 is fixedly connected to the upper surface of the support frame 21. One side of the discharge plate 22 extends to the interior of the ball mill 13 and is fixedly connected to a fixed plate 23 rotatably connected to the outer surface of the rear partition 151. The circumferential outer surface of the fixed plate 23 fits the inner wall surface of the ball mill 13. A discharge piece 24 is provided on the side of the fixed plate 23 away from the rear partition 151. The outer surface of the support frame 21 is fixedly connected to a support cylinder 25 that fits the inner wall of the ball mill 13. The section from the feed inlet 130 to the front partition 15 is a coarse crushing chamber, in which a large number of grinding balls with a larger diameter are placed; the section from the front partition 15 to the rear partition 151 is a fine grinding chamber, in which a small number of grinding balls with a smaller diameter are placed; the section from the fixed plate 23 to the support cylinder 25 is a discharge chamber, which is used for fine screening of NdFeB powder with a particle size that meets the requirements for discharge;

[0036] A column 14 is provided at the axis center in the middle of the ball mill 13, and a front partition 15 fixedly connected to the circumferential inner wall of the ball mill 13 is provided at one end of the column 14 close to the feed port 130, and a rear partition 151 fixed to the circumferential inner wall of the ball mill 13 is provided at one end of the column 14 away from the front partition 15.

[0037] A placement groove 141 is provided on the circumferential outer surface of the cylinder 14, and the placement groove 141 is rotatably connected to a toggle plate 142 through an axis rod provided on its inner wall surface. The side of the placement groove 141 away from the axis rod adopts a bevel design, and a limiting member is provided on the side of the placement groove 141 close to the axis rod, which can support the toggle plate 142 to unfold and drive the material to flip.

[0038] The outer surface of the toggle plate 142 adopts a curved surface design. There are multiple toggle plates 142 arranged in a circular array around the cylinder 14 . The toggle plates 142 can also adopt an inclined design to drive the material to move radially inside the ball mill 13 .

[0039] The unloading part 24 and the side of the fixed plate 23 away from the rear partition 151 are rotatably connected to the eccentric cylinder 241, and the end of the eccentric cylinder 241 away from the fixed plate 23 is nested in the outer surface of the support cylinder 25. A sieve hole 2411 is provided inside the eccentric cylinder 241. The left side of the eccentric cylinder 241 is farthest away from the inner wall surface of the ball mill 13. A cleaning part 26 that can be used to clean the sieve hole 2411 is provided inside the eccentric cylinder 241.

[0040] A notch 2412 is provided inside the eccentric cylinder 241, and the ball mill 13 is provided with a support plate 242 through a groove body provided on its inner circumferential surface. The outer surface of the support plate 242 fits the inner wall surface of the notch 2412, and two support plates 242 are provided and distributed in a circular array inside the ball mill 13.

[0041] The cleaning member 26 includes a fixed frame 261, one side of which is fixedly connected to the side of the fixed plate 23 close to the support plate 242. The fixed frame 261 is connected to a connecting plate 263 through an elastic member 262 arranged on the side close to the axis of the eccentric cylinder 241. The middle part of the connecting plate 263 close to the elastic member 262 is fixedly connected to a through column 264 that fits the inner wall surface of the sieve hole 2411.

[0042] The outer surface of the fixed frame 261 is rotatably connected to an eccentric roller 265 that fits with the side of the connecting plate 263 away from the through column 264. The outer end of the eccentric roller 265 is fixedly connected to a gear 266. The side of the gear 266 away from the eccentric roller 265 is rotatably connected to the outer surface of the support tube 25. The inner wall surface of the eccentric tube 241 is fixedly connected to a gear ring 267 that meshes with the outer surface of the gear 266.

[0043] The outer end of the through-column 264 is designed with a conical surface. A through hole is formed on a side of the support plate 242 close to the through-column 264 . A grate hole 231 is formed inside the fixing plate 23 .

[0044] In actual application, the blocky NdFeB alloy ingot raw material is added to the ball mill 13 from the feed port 130. The ball mill 13 is mainly divided into three chambers, corresponding to the coarse crushing chamber, the fine grinding chamber and the unloading chamber, wherein the section from the feed port 130 to the front partition 15 is the coarse crushing chamber, in which a large number of grinding balls with a larger diameter are placed; the section from the front partition 15 to the rear partition 151 is the fine grinding chamber, in which a small number of grinding balls with a smaller diameter are placed; the section from the fixed plate 23 to the support tube 25 is the unloading chamber, which is used for fine screening of NdFeB powder with a particle size that meets the requirements for unloading.

[0045] The process of coarse crushing of NdFeB alloy ingots:

[0046] Initially, a massive NdFeB alloy ingot enters the coarse crushing chamber through the feed port 130 in the grinding unit 1. The drive seat on the upper surface of the fixed base 11 is activated, driving the ball mill 13 to rotate within the bearing housing 12. The high-speed grinding balls within the ball mill 13 continuously swing in a circular motion, generating a significant impact force as they strike the NdFeB alloy ingot. After entering the coarse crushing chamber, the NdFeB alloy ingot falls to the bottom of the ball mill 13 under the influence of gravity, where the high-speed grinding balls immediately impact the NdFeB alloy ingot. This immense impact force instantly creates stress concentration within the NdFeB alloy ingot, causing cracks to appear on its surface and causing it to break into larger chunks. These fragmented chunks, driven by the impact of the grinding balls and the airflow within the chamber, are thrown toward the top of the chamber, where they collide and rub against each other again, breaking them into smaller chunks.

[0047] Inside the coarse crushing chamber, at the end away from the feed inlet 130, a front baffle 15 is installed. Both the front baffle 15 and the rear baffle 151 are provided with sieve holes 2411, providing excellent toughness and wear resistance. As the crushed material continuously moves within the coarse crushing chamber, it comes into contact with the front baffle 15. Material that meets certain particle size requirements, i.e., particles with a particle size smaller than a preset size, passes through the mesh of the front baffle 15 and enters the subsequent fine grinding chamber for further processing. Larger particles that fail to pass through the front baffle 15 remain in the coarse crushing chamber, where they are repeatedly impacted and squeezed by the grinding balls and the inner wall of the ball mill 13 until they reach the required particle size and are discharged through the rear baffle 151.

[0048] The process of fine grinding of NdFeB alloy ingots:

[0049] The NdFeB alloy ingot passes through the front baffle 15 and enters the fine grinding chamber. The fine grinding chamber is an annular space as a whole. In the radial range, it consists of the space between the front baffle 15 and the rear baffle 151, and in the axial range, it consists of the space between the circumferential inner wall of the ball mill 13 and the circumferential outer surface of the cylinder 14. The grinding balls in the fine grinding chamber perform a circular falling or cascading motion under the action of centrifugal force and gravity. Under the action of the annular grinding area, the grinding balls and the material need to move around the cylinder 14. The grinding balls collide with the cylindrical surface, generating a tangential velocity component and forming a spiral motion trajectory. This increases the sliding friction and shearing effect between the grinding balls, enhances radial motion, and the cylinder 14 at the axis fills the dead volume in the traditional central control cavity, forcing the material to flow in the annular area to avoid the retention of coarse particles.

[0050] As the ball mill 13 rotates clockwise, the column 14, fixed to the mill via the front and rear baffles 15 and 151, also rotates synchronously. Multiple groups of toggle plates 142 and placement slots 141 are arranged axially, each containing multiple circular arrays. Under the influence of gravity, the outer end of the bottommost toggle plate 142 naturally droops downward, centered on the shaft. As the column 14 rotates, the toggle plate 142 drives the NdFeB material and grinding balls, located at the bottom of the mill 13, into a synchronous circular motion.

[0051] When the toggle plate 142 rotates to the left, it expands to its maximum extent. A limiter is provided on the side of the placement slot 141 near the shaft, supporting the expansion of the toggle plate 142 and causing the material to flip. As the toggle plate 142 continues to rotate clockwise and passes its highest point, the material between the placement slot 141 and the concave arc surface of the toggle plate 142 naturally flows out to the right. The beveled edge of the placement slot 141, away from the shaft, allows the material to flow out from the right under the action of gravity. The toggle plate 142 can also rotate around the shaft, returning its concave arc surface to abut against the inner wall of the placement slot 141.

[0052] When the toggle plate 142 is rotated to the right, it is retracted, with the convex surface of the toggle plate 142 aligning with the curvature of the outer circumference of the cylinder 14. After being moved around the left side of the cylinder 14 to the top by the toggle plate 142, the grinding balls and material then naturally roll down from the right side, following the curvature of the cylinder 14, unhindered by the toggle plate 142. During this descent, the grinding balls and the NdFeB material flakes grind and compress each other.

[0053] Compared to the axial drop pattern of conventional hollow ball mills with a ball mill barrel 13, the shear effect contributes significantly to the milling process, making it more suitable for the complete, dead-angle grinding of flaky particles during the fine grinding stage. The grinding balls and flaky material are positioned between the cylinder 14 and the ball mill barrel 13 (within the radial range). This limited grinding zone eliminates the dead volume in the center of a conventional ball mill, allowing all grinding balls to participate effectively in the grinding process and increasing the average collision frequency of the material particles. Furthermore, the width of the annular gap constrains the movement of the grinding balls, preventing excessive crushing of fine powders caused by the high-speed drop of large grinding balls. This makes it suitable for grinding sensitive materials such as NdFeB powders. Shear milling achieves higher energy efficiency than impact milling, reducing energy consumption while achieving the same fineness. This ball mill achieves a multi-stage milling effect through spatial gradients in diameter within the mill chamber, shortening grinding time and improving grinding efficiency.

[0054] As the ground NdFeB material continuously moves within the fine grinding chamber, it comes into contact with the rear baffle 151. Material that meets certain particle size requirements, i.e., particles with a particle size smaller than the preset size of the screen on the surface of the rear baffle 151, will pass through the mesh of the rear baffle 151 and enter the subsequent discharge chamber to await discharge. Larger particles of NdFeB material that fail to pass through the rear baffle 151 will remain in the fine grinding chamber and, under the continuous action of the grinding balls, the outer surface of the cylinder 14, and the inner wall of the ball mill 13, will be repeatedly sheared and ground until the required particle size is reached and discharged through the rear baffle 151.

[0055] The process of cutting NdFeB alloy ingots:

[0056] The outer surface of the fixed plate 23 fits into the outer surface of the rear partition 151. The fixed plate 23 is fixedly connected to the fixed seat 11 through the discharge plate 22 and the support frame 21. When the ball mill 13 rotates, the two move relative to each other. Among them, grate holes 231 are opened in other positions inside the fixed plate 23 except the range where the eccentric cylinder 241 is located. When the screen on the surface of the rear partition 151 coincides with the grate holes 231 of the fixed plate 23, the powdered NdFeB material enters the discharge chamber.

[0057] The left side of the circumferential outer surface of the eccentric cylinder 241 is farthest from the inner wall surface of the ball mill 13, while the right side of the circumferential outer surface of the eccentric cylinder 241 is closest to the inner wall surface of the ball mill 13. From the fine grinding chamber to the discharge chamber, the NdFeB powder mostly enters from the bottom of the circumferential direction to the bottom of the crescent-shaped space formed by the inner wall of the ball mill 13 and the eccentric cylinder 241. As the ball mill 13 continues to rotate, the support plate 242 moves synchronously with the ball mill 13 through the tank body. The support plate 242 can swing at a small angle within the tank body, so that it can contact the inner wall of the notch 2412 at different angles, driving the eccentric cylinder 241 to rotate. The overall state is relatively static.

[0058] There are two support plates 242 arranged in a circular array along the axis of the ball mill 13. The support plates 242 rotate synchronously clockwise with the ball mill 13. The outer ends of the support plates 242 pass through the notch 2412 and enter the interior of the eccentric cylinder 241 (one side of the support plate 242 is in contact with the outer surface of the fixed plate 23, and the other side of the support plate 242 is in contact with the outer surface of the support cylinder 25), and drive the eccentric cylinder 241 to rotate clockwise around its own axis between the fixed plate 23 and the support cylinder 25.

[0059] In the initial state, the support plate 242 is located on the right side of the ball mill 13. At this time, the outer end of the support plate 242 passes through the notch 2412, and most of the outer end enters the interior of the eccentric cylinder 241. As the ball mill 13 continues to rotate clockwise, the distance between the side of the support plate 242 close to the axis of the ball mill 13 and the inner wall surface of the eccentric cylinder 241 gradually decreases, the part of the support plate 242 located in the inner cavity gradually decreases, and the part of the support plate 242 located in the crescent-shaped cavity gradually increases (the cavity enclosed inside the eccentric cylinder 241 is the inner cavity, and the cavity enclosed from the outer surface of the circumference of the eccentric cylinder 241 to the inner wall of the circumference of the ball mill 13 is the crescent-shaped cavity). Since the material entering the fine grinding chamber first arrives inside the crescent-shaped cavity, the support plate 242 is always connected to the ball mill 13 and the eccentric cylinder 241. When the support plate 242 gradually moves clockwise from the right end to the bottom end and then to the left end, the support plate 242 will drive the NdFeB powder at the bottom to flip upward.

[0060] As support plate 242 moves from the left end of eccentric cylinder 241 to the upper end and then to the right end, the NdFeB powder reaches a position near the upper portion of the outer surface of eccentric cylinder 241. Powder that meets the required particle size enters the inner cavity through sieve holes 2411 in eccentric cylinder 241 and falls onto the upper surface of discharge plate 22, where it is discharged under the action of gravity (discharge plate 22 is inclined, with the side of discharge plate 22 near feed port 130 being higher). Powder that does not meet the required particle size (larger than sieve holes 2411) remains on the outer surface of eccentric cylinder 241. In the process of the support plate 242 moving toward the right end of the eccentric cylinder 241, the distance between the side of the support plate 242 close to the axis of the ball mill 13 and the inner wall surface of the eccentric cylinder 241 gradually increases, the part of the support plate 242 located in the inner cavity gradually increases, and the part of the support plate 242 located in the crescent-shaped cavity gradually decreases, and the space in the axial range of the neodymium iron boron powder located on the outer surface of the eccentric cylinder 241 gradually decreases.

[0061] As the ball mill 13 continues to rotate, the larger NdFeB particles are subjected to the extrusion and shear force between the outer surface of the eccentric cylinder 241 and the inner surface of the ball mill 13 (similar to two rollers). After the NdFeB particles are squeezed to the required size, they enter the lower part of the eccentric cylinder 241 through the sieve holes 2411. As the ball mill 13 rotates, the material, after meeting the required size, falls through the sieve holes 2411 again into the crescent-shaped cavity at the bottom of the inner wall of the ball mill 13. After waiting for a while, the support plate 242 flips it again and moves it. The NdFeB powder that has passed the screening is once again raised to the top of the ball mill 13. Those with qualified particle size fall through the sieve holes 2411 at the top into the inner cavity and slide down the discharge plate 22 to complete the discharge action. The unqualified NdFeB powder continues to remain on the outer surface to participate in the next round of squeezing. This forms a repetitive cycle of grinding and screening, preventing material from being retained in a single area and improving overall grinding efficiency. The sieve hole 2411 ensures that only NdFeB powder that has been fully crushed and has reached the particle size standard can pass through, thus preventing insufficiently ground particles from being discharged prematurely.

[0062] During this process, due to the magnetic properties of the NdFeB material, fine powder may be adsorbed into agglomerates and clog the sieve holes 2411. In actual applications, the eccentric cylinder 241 is relatively thin, and the length of the penetrating column 264 is much greater than the thickness of the eccentric cylinder 241. The gear ring 267 is fixedly connected to the inner wall surface of the eccentric cylinder 241 and rotates synchronously with the ball mill 13. The fixed frame 261 is fixedly connected to the fixed plate 23, the support frame 21, the discharge plate 22, and the fixed seat 11. During rotation, the gear ring 267 will move relative to the gear 266 rotating on the outer surface of the fixed frame 261, driving the gear 266 to rotate on the outer surface of the support cylinder 25. In the initial state, the fixed frame 261 is always in a fixed position. Under the action of the elastic member 262 (the elastic member 262 is preferably an elastic plate), the distance between the connecting plate 263 and the fixed frame 261 is relatively far. The outer end of the through-column 264 is flush with the outer surface of the fixed frame 261. The through-column 264 is in a contracted state (the through-column 264 is preferably made of non-magnetic stainless steel to avoid adsorbing neodymium iron boron powder) and has no contact with the inner wall of the eccentric cylinder 241. In the initial state, the eccentric distance of the left side of the eccentric roller 265 (the side close to the through-column 264) is smaller, and the eccentric distance of the right side of the eccentric roller 265 is larger.

[0063] When the gear ring 267 drives the gear 266 to rotate on the outer surface of the support cylinder 25, the axis of the gear 266 coincides with the axis of the eccentric roller 265. Under the action of the gear 266, the eccentric roller 265 rotates, driving the right side of the eccentric roller 265 with the larger eccentricity toward the through-post 264, squeezing the connecting plate 263 toward the fixed frame 261. The elastic member 262 is squeezed and elastically deformed, and the through-post 264 moves synchronously and penetrates the sieve holes 2411 inside the eccentric cylinder 241, thereby cleaning the sieve holes 2411. There are multiple sieve holes 2411 arranged in the circumferential direction of the eccentric cylinder 241. The gear ring 267 rotates synchronously with the eccentric cylinder 241. Each time the eccentric cylinder 241 moves from one sieve hole 2411 to the next sieve hole 2411 in the radial direction, it drives the through-post 264 to extend and retract the sieve hole 2411 to complete the cleaning. When the support plate 242 moves to the position of the through-pillar 264 , the through-pillar 264 will also extend to the through-hole position inside the support plate 242 to avoid collision.

[0064] In summary, the ball mill equipment has the following advantages:

[0065] Advantage 1: The ball mill 13 is divided into three chambers (coarse crushing chamber, fine grinding chamber and feeding chamber), which can realize graded grinding of materials and gradient grinding from coarse grinding area to fine grinding area. The average particle size distribution deviation is small, the grinding time is shortened, and it is beneficial to improve production efficiency.

[0066] Advantage 2: Within the fine grinding chamber (between the front baffle 15 and the rear baffle 151), the grinding balls rotate in a circular motion within the annular gap between the cylinder 14 and the inner wall of the ball mill 13. The rotation of the cylinder 14 drives the shifting plates 142 to periodically flip the material, evenly applying force to the flaky NdFeB material. This solves the problem of over-grinding at the edges and under-grinding at the center of conventional ball mills. Each set of shifting plates 142 (multiple in a circular array) rotates with the cylinder 14, with adjacent sets staggered. They expand on the left side to flip the material and contract on the right side (conforming to the surface of the cylinder 14) to allow the material to slide naturally. This ensures that the material and the grinding balls rub and grind each rotation, improving the efficiency of agglomerate dispersion.

[0067] Advantage 3: In the discharge chamber, support plate 242 is linked to ball mill 13 via the trough, leveraging the geometric constraints of gap 2412 in eccentric barrel 241 to achieve swinging motion. This eliminates the need for an additional power source and reduces energy consumption compared to traditional vibratory screening. Eccentric barrel 241 and the inner wall of ball mill 13 form a crescent-shaped cavity that is wider on the left and narrower on the right. Material enters from below and is carried by support plate 242 to the wide gap on the left as ball mill 13 rotates. As the mill continues to rotate, larger particles are retained on the outer surface of eccentric barrel 241, while finer particles that meet the requirements pass through sieve holes 2411 and enter the inner cavity for discharge. When the large particles that fail to pass through the sieve hole 2411 rotate with the eccentric cylinder 241 to the narrow gap on the right, they are subjected to the extrusion and shearing force between the outer surface of the eccentric cylinder 241 and the inner wall of the ball mill 13. The pressure is relatively large, similar to the effect of two rollers rolling, so that the NdFeB particles are further crushed to meet the standards, and the extruded material is screened again until it meets the standards and falls into the discharge plate 22 to complete the discharge, thereby completing the cyclic screening and ensuring the particle size of the material after ball milling when discharging.

[0068] Advantage 4: When the eccentric cylinder 241 rotates, the gear ring 267 drives the gear 266 to drive the eccentric roller 265 to swing, squeezing the elastic member 262 so that the penetrating column 264 periodically penetrates the sieve hole 2411, removing the magnetic fine powder agglomerates adsorbed on the sieve hole 2411. The cleaning member 26 prevents the sieve hole 2411 from being blocked, ensuring the continuity of the screening process.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A NdFeB powder ball mill cavity assembly based on cavity diameter gradient grinding, characterized in that: include: A grinding part (1), the grinding part (1) comprising a fixed seat (11), the fixed seat (11) being rotatably connected to a ball mill (13) via a bearing seat (12) provided on an upper surface thereof, one end of the ball mill (13) being fixedly connected to a feed port (130); A discharge portion (2), the discharge portion (2) comprising a support frame (21) fixed to the upper surface of a fixed seat (11), a discharge plate (22) fixedly connected to the upper surface of the support frame (21), one side of the discharge plate (22) extending to the interior of the ball mill (13) and fixedly connected to a fixed plate (23) rotatably connected to the outer surface of the rear partition (151), the circumferential outer surface of the fixed plate (23) being in contact with the inner wall surface of the ball mill (13), a discharge piece (24) being provided on the side of the fixed plate (23) away from the rear partition (151), and the outer surface of the support frame (21) being fixedly connected to a support cylinder (25) in contact with the inner wall of the ball mill (13); A column (14) is provided at the axis center of the middle part of the ball mill (13); a front baffle (15) fixedly connected to the circumferential inner wall of the ball mill (13) is provided at one end of the column (14) close to the feed port (130); and a rear baffle (151) fixed to the circumferential inner wall of the ball mill (13) is provided at one end of the column (14) away from the front baffle (15); The blanking member (24) and the fixed plate (23) are rotatably connected to an eccentric cylinder (241) on one side away from the rear partition (151), and one end of the eccentric cylinder (241) away from the fixed plate (23) is nested in the outer surface of the support cylinder (25). A sieve hole (2411) is provided inside the eccentric cylinder (241), and the left side of the eccentric cylinder (241) is farthest away from the inner wall surface of the ball mill (13). A cleaning member (26) for cleaning the sieve hole (2411) is provided inside the eccentric cylinder (241). A notch (2412) is provided inside the eccentric cylinder (241). The ball mill (13) is provided with a support plate (242) through a groove body provided on its circumferential inner surface. The outer surface of the support plate (242) fits the inner wall surface of the notch (2412). Two support plates (242) are provided and circumferentially distributed inside the ball mill (13).

2. The NdFeB powder ball mill cavity assembly based on cavity diameter gradient grinding according to claim 1, characterized in that: A placement groove (141) is provided on the circumferential outer surface of the column (14), and the placement groove (141) is rotatably connected to a toggle plate (142) via a shaft provided on the inner wall surface thereof.

3. The NdFeB powder ball mill cavity assembly based on cavity diameter gradient grinding according to claim 2, characterized in that: The outer surface of the toggle plate (142) adopts a curved surface design, and the toggle plate (142) is provided with a plurality of plates distributed in a circular array with the column (14) as the center.

4. The NdFeB powder ball mill cavity assembly based on cavity diameter gradient grinding according to claim 1, characterized in that: The cleaning member (26) comprises a fixed frame (261), one side of the fixed frame (261) being fixedly connected to a side of the fixed plate (23) close to the support plate (242), the fixed frame (261) being connected to a connecting plate (263) via an elastic member (262) arranged on a side close to the axis of the eccentric cylinder (241), and a through column (264) in contact with the inner wall surface of the sieve hole (2411) being fixedly connected to the middle portion of the connecting plate (263) close to the elastic member (262).

5. The NdFeB powder ball mill cavity assembly based on cavity diameter gradient grinding according to claim 4, characterized in that: The outer surface of the fixed frame (261) is rotatably connected to an eccentric roller (265) that is in contact with the side of the connecting plate (263) away from the through-column (264); the outer end of the eccentric roller (265) is fixedly connected to a gear (266); the side of the gear (266) away from the eccentric roller (265) is rotatably connected to the outer surface of the support cylinder (25); and the inner wall surface of the eccentric cylinder (241) is fixedly connected to a gear ring (267) that meshes with the outer surface of the gear (266).

6. The NdFeB powder ball mill cavity assembly based on cavity diameter gradient grinding according to claim 5, characterized in that: The outer end of the through-column (264) is designed with a conical surface, a through hole is provided on a side of the support plate (242) close to the through-column (264), and a grate hole (231) is provided inside the fixing plate (23).

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