Neodymium-iron-boron powder ball-milling cavity assembly based on cavity variable-diameter gradient grinding

Abstract

The invention relates to the technical field of neodymium-iron-boron powder ball milling, and discloses a neodymium-iron-boron powder ball milling cavity assembly based on cavity variable-diameter gradient grinding, the neodymium-iron-boron powder ball milling cavity assembly comprises a grinding part, the grinding part comprises a fixed seat, and the fixed seat is rotatably connected with a ball milling cylinder through a bearing seat arranged on the upper surface of the fixed seat. The neodymium-iron-boron powder ball-milling cavity assembly based on cavity variable-diameter gradient grinding can effectively solve the problems that in the prior art, neodymium-iron-boron powder grinding needs to be different in different stages during ball milling, large-particle raw materials need to be crushed through large impact force in the initial stage, the mild and fine grinding effect is needed along with grinding, and the grinding efficiency is poor. The problems that due to excessive grinding, particle aggregation or crystal structure damage is caused, and the magnetism and other performance of neodymium iron boron powder are affected are solved, however, an existing ball mill usually adopts a single grinding mode, the grinding strength and mode cannot be automatically adjusted according to the change of the material granularity, and gradient change from coarse grinding to fine grinding is difficult to achieve are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of neodymium iron boron powder ball milling, and particularly relates to a ball milling cavity assembly for neodymium iron boron powder based on variable-diameter gradient grinding in a cavity. Background Art

[0002] As an important magnetic material, neodymium iron boron powder is widely used in modern industry. A ball mill is a commonly used device for grinding neodymium iron boron 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 body, so that the particle size of the material gradually decreases to meet the requirements of subsequent production processes.

[0003] In the prior art, the grinding requirements of neodymium iron boron powder are different at different stages during ball milling. In the initial stage, a large impact force is required to break large particles of the raw material. As the grinding progresses, a mild and fine grinding effect is more needed to avoid over-grinding causing particle agglomeration or crystal structure damage, which affects the magnetic properties and other properties of neodymium iron boron powder. However, existing ball mills usually adopt a single grinding mode and cannot automatically adjust the grinding force and method according to the change of the material particle size, making it difficult to achieve a gradient change from coarse grinding to fine grinding. Summary of the Invention

[0004] In view of the above-mentioned drawbacks of the prior art, the present invention provides a ball milling cavity assembly for neodymium iron boron powder based on variable-diameter gradient grinding in a cavity, which can effectively solve the problem in the prior art that the grinding requirements of neodymium iron boron powder are different at different stages during ball milling. In the initial stage, a large impact force is required to break large particles of the raw material. As the grinding progresses, a mild and fine grinding effect is more needed to avoid over-grinding causing particle agglomeration or crystal structure damage, which affects the magnetic properties and other properties of neodymium iron boron powder. However, existing ball mills usually adopt a single grinding mode and cannot automatically adjust the grinding force and method according to the change of the material particle size, making it difficult to achieve a gradient change from coarse grinding to fine grinding.

[0005] To achieve the above object, the present invention is realized through the following technical solutions: The present invention provides a ball milling cavity assembly for neodymium iron boron powder based on variable-diameter gradient grinding in a cavity, including: A grinding part, the grinding part includes a fixed seat, the fixed seat is rotatably connected with a ball mill cylinder through a bearing seat arranged on its upper surface, and one end of the ball mill cylinder is fixedly communicated with a feed port; 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; 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.

[0006] 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.

[0007] 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] 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.

[0012] Furthermore, the outer end of the through-column is designed with a conical surface. A through-hole is provided on one side of the support plate close to the through-column, and a grate hole is provided inside the fixing plate.

[0013] The technical solution provided by the present invention has the following beneficial effects compared with the prior art: The present invention is provided with a ball milling cylinder, a front partition board, a rear partition board, a column body and a blanking member. The inside of the ball milling cylinder is divided into three chambers: a coarse crushing chamber, a fine grinding chamber and a blanking chamber. In the coarse crushing chamber, the impact force of the high-speed dropping of the grinding balls is used to quickly crush the massive neodymium iron boron alloy ingot; in the fine grinding chamber, the column body rotates to drive the stirring plate to periodically turn over the material, so that the flaky material is uniformly stressed, solving the problem of excessive grinding at the edge and insufficient grinding in the center in traditional ball milling; in the blanking chamber, a crescent-shaped gap is formed between the eccentric cylinder and the inner wall of the ball milling cylinder, and the support plate is used to turn over the material, realizing a cyclic process of screening, extrusion and re-screening, ensuring that only the neodymium iron boron particles with a particle size meeting the requirements pass through the sieve holes, and the qualified rate of the discharged material is improved. Through the three chambers, the classification grinding of the material can be realized, the gradient grinding from the coarse grinding area to the fine grinding area can be realized, the deviation of the average particle size distribution is small, the grinding time is shortened, and it is beneficial to improve the production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0015] Figure 1 is a three-dimensional structural schematic diagram of an embodiment of the present invention; Figure 2 is a sectional structural schematic diagram of the ball milling cylinder of an embodiment of the present invention; Figure 3 is a structural schematic diagram of the front partition board, the column body, the rear partition board, the fixing plate, the eccentric cylinder and the support cylinder of an embodiment of the present invention; Figure 4 is a separated structural schematic diagram of the rear partition board and the fixing plate of an embodiment of the present invention; Figure 5 is a sectional structural schematic diagram of the column body and the stirring plate of an embodiment of the present invention; Figure 6 is a sectional structural schematic diagram of the ball milling cylinder and the support plate of an embodiment of the present invention; Figure 7 is an embodiment of the present invention Figure 6 The enlarged partial structural schematic diagram at A in; Figure 8 is a separated structural schematic diagram of the discharging part of an embodiment of the present invention; Figure 9 Schematic diagram of the structure of the cleaning element according to an embodiment of the present invention.

[0016] 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

[0017] 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.

[0018] The present invention will be further described below in conjunction with the embodiments.

[0019] Example:

[0020] 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: 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. Discharging section 2, the discharging section 2 includes a support frame 21 fixed on the upper surface of the fixed seat 11. The upper surface of the support frame 21 is fixedly connected with a discharge plate 22. One side of the discharge plate 22 extends into the interior of the ball mill cylinder 13 and is fixedly connected with a fixing plate 23 rotatably connected to the outer surface of the rear partition plate 151. The circumferential outer surface of the fixing plate 23 fits with the inner wall surface of the ball mill cylinder 13. A blanking member 24 is arranged on the side of the fixing plate 23 away from the rear partition plate 151. The outer surface of the support frame 21 is fixedly connected with a support cylinder 25 that fits with the inner wall of the ball mill cylinder 13. The area from the feed inlet 130 to the front partition plate 15 is the coarse crushing chamber, where a larger number of grinding balls with larger diameters are placed; the area between the front partition plate 15 and the rear partition plate 151 is the fine grinding chamber, where a smaller number of grinding balls with smaller diameters are placed; the area between the fixing plate 23 and the support cylinder 25 is the blanking chamber, which is used for finely screening neodymium iron boron powder with particle sizes meeting the requirements for blanking; A column 14 is arranged at the central axis of the middle part of the ball mill cylinder 13. One end of the column 14 close to the feed inlet 130 is provided with a front partition plate 15 fixedly connected to the circumferential inner wall of the ball mill cylinder 13. One end of the column 14 away from the front partition plate 15 is provided with a rear partition plate 151 fixedly connected to the circumferential inner wall of the ball mill cylinder 13.

[0021] A placement groove 141 is formed on the circumferential outer surface of the column 14. The placement groove 141 is rotatably connected with a toggle plate 142 through a shaft rod arranged on its inner wall surface. The side of the placement groove 141 away from the shaft rod is designed with a bevel edge. A limiting member is arranged on the side of the placement groove 141 close to the shaft rod, which can support the toggle plate 142 to unfold and drive the material to be flipped.

[0022] The outer surface of the toggle plate 142 is designed with an arc surface. A plurality of toggle plates 142 are arranged and distributed in a circumferential array centered on the column 14. The toggle plate 142 can also be designed in an inclined manner to drive the material to move radially inside the ball mill cylinder 13.

[0023] Blanking member 24, one side of the fixing plate 23 away from the rear partition plate 151 is rotatably connected with an eccentric cylinder 241. One end of the eccentric cylinder 241 away from the fixing plate 23 is nested on the outer surface of the support cylinder 25. A sieve hole 2411 is formed inside the eccentric cylinder 241. The distance between the left side of the eccentric cylinder 241 and the inner wall surface of the ball mill cylinder 13 is the farthest. A cleaning member 26 that can be used to clean the sieve hole 2411 is arranged inside the eccentric cylinder 241.

[0024] A notch 2412 is formed inside the eccentric cylinder 241. The ball mill cylinder 13 is provided with a support plate 242 through a groove formed on its circumferential inner surface. The outer surface of the support plate 242 fits with the inner wall surface of the notch 2412. Two support plates 242 are arranged and distributed in a circumferential array inside the ball mill cylinder 13.

[0025] The cleaning member 26 includes a fixed frame 261. One side of the fixed frame 261 is fixedly connected to one 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 provided on the side close to the axis of the eccentric cylinder 241. The middle part of the side 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.

[0026] The outer surface of the fixed frame 261 is rotatably connected to an eccentric roller 265 that fits 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. The inner wall surface of the eccentric cylinder 241 is fixedly connected to a toothed ring 267 that meshes with the outer surface of the gear 266.

[0027] The outer end of the through column 264 is designed with a conical surface. A through hole is opened on one side of the support plate 242 close to the through column 264, and a grid hole 231 is opened inside the fixed plate 23.

[0028] In practical applications, the massive neodymium iron boron alloy ingot raw material is added to the ball milling cylinder 13 from the feed inlet 130. The ball milling cylinder 13 is mainly divided into three chambers, corresponding to the coarse crushing chamber, the fine grinding chamber, and the blanking chamber respectively. Among them, the area from the feed inlet 130 to the front partition 15 is the coarse crushing chamber, which contains a large number of grinding balls with a larger diameter; the area between the front partition 15 and the rear partition 151 is the fine grinding chamber, which contains a small number of grinding balls with a smaller diameter; the area between the fixed plate 23 and the support cylinder 25 is the blanking chamber, which is used for fine screening of neodymium iron boron powder with a particle size meeting the requirements for blanking.

[0029] The process of coarse crushing the neodymium iron boron alloy ingot: In the initial state, the massive neodymium iron boron alloy ingot enters the coarse crushing chamber from the feed inlet 130 in the grinding part 1. The driving seat on the upper surface of the fixed seat 11 is started to drive the whole ball milling cylinder 13 to rotate inside the bearing seat 12. The grinding balls rotating at a high speed in the ball milling cylinder 13 constantly wave in a circular motion trajectory, and can generate a large impact force when hitting the neodymium iron boron alloy ingot. After the neodymium iron boron alloy ingot enters the coarse crushing chamber, it falls to the bottom of the ball milling cylinder 13 under the action of gravity. At this time, the grinding balls rotating at a high speed immediately hit the neodymium iron boron alloy ingot. A huge impact force instantly generates stress concentration inside the neodymium iron boron alloy ingot, causing cracks to appear on the surface of the neodymium iron boron alloy ingot, and the neodymium iron boron alloy ingot begins to break into larger blocks. These fragmented block-shaped materials are thrown to the top of the chamber under the beating of the grinding balls and the pushing of the internal air flow of the chamber, and collide and rub again, and are further broken into smaller block-shaped objects.

[0030] Inside the coarse crushing chamber, at one end far from the feed port 130, a front partition 15 is provided. Sieve holes 2411 are formed inside both the front partition 15 and the rear partition 151, which have good toughness and wear resistance. During the continuous movement of the crushed material in the coarse crushing chamber, it will contact the front partition 15. The material that meets certain particle size requirements, that is, the particles with a particle diameter smaller than the preset size, will pass through the mesh holes of the front partition 15 and enter the subsequent fine grinding chamber for further processing. The larger particle material that fails to pass through the front partition 15 will continue to stay in the coarse crushing chamber and will be repeatedly impacted and extruded under the continuous action of the grinding balls and the inner wall of the ball mill cylinder 13 until it reaches the required particle size and is discharged through the rear partition 151.

[0031] The process of fine grinding the neodymium iron boron alloy ingot: The neodymium iron boron alloy ingot passes through the front partition 15 and enters the fine grinding chamber. The fine grinding chamber is an overall annular space, which is composed of the space between the front partition 15 and the rear partition 151 in the radial range and the space between the circumferential inner wall of the ball mill cylinder 13 and the circumferential outer surface of the cylinder 14 in the axial range. The grinding balls in the fine grinding chamber perform circular throwing or cascading motions under the action of centrifugal force and gravity. Under the action of the annular grinding area, the grinding balls and the material need to bypass the cylinder 14 to move. The grinding balls collide on the cylindrical surface, generating a tangential velocity component and forming a spiral motion trajectory, increasing the sliding friction and shear action between the grinding balls, enhancing the radial movement. 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 and preventing the retention of coarse particles.

[0032] As the ball mill cylinder 13 rotates clockwise, the cylinder 14 fixedly connected to the front partition 15, the rear partition 151 and the ball mill cylinder 13 also rotates clockwise synchronously. Multiple groups of the dialing plates 142 and the placement grooves 141 are arranged in the axial direction, and each group is circumferentially arrayed with multiple ones. The dialing plate 142 at the bottommost rotates naturally downward at the outer end with the shaft rod as the center under the action of gravity. As the cylinder 14 rotates, the dialing plate 142 drives the sheet-shaped neodymium iron boron material and the grinding balls at the bottom of the ball mill cylinder 13 to perform circular motions synchronously.

[0033] When the dialing plate 142 rotates to the left, the degree of expansion of the dialing plate 142 is the largest. A limiting member is provided on one side of the placement groove 141 close to the shaft rod, which can support the expansion of the dialing plate 142 and drive the material to flip. When the dialing plate 142 continues to rotate clockwise and passes through the highest point, the material between the placement groove 141 and the concave arc surface of the dialing plate 142 flows out naturally to the right. The side of the placement groove 141 away from the shaft rod is designed with an inclined edge, which can smoothly make the material flow out from the right under the action of gravity. The dialing plate 142 can also rotate around the shaft rod to make it return to the state where the concave arc surface fits the inner wall surface of the placement groove 141.

[0034] When the toggle plate 142 rotates to the right position, the toggle plate 142 is in a contracted state, and the convex arc surface of the toggle plate 142 has the same radian as the outer surface of the circumference of the cylinder 14. After the grinding balls and the material are toggled by the toggle plate 142 to the top on the left side of the cylinder 14, the grinding balls and the material then naturally roll down along the radian of the cylinder 14 from the right side without being obstructed by the toggle plate 142. During the falling process, the grinding balls and the flaky neodymium iron boron material grind and extrude each other.

[0035] Compared with the axial throwing mode of the hollow ball milling in the traditional ball milling cylinder 13, the proportion of the shearing action is increased, which is more suitable for the dead-angle-free grinding of cutting and crushing of flaky particles in the fine grinding stage. The grinding balls and the flaky material are located between the cylinder 14 and the ball milling cylinder 13 (within the radial range). By limiting the grinding area, the dead volume in the center of the traditional ball milling is eliminated, so that all the grinding balls participate in effective grinding, and the average collision frequency of the material particles is increased. At the same time, the width of the annular gap restricts the movement space of the grinding balls, avoiding the excessive crushing of fine powder caused by the high-speed throwing of large grinding balls, and is suitable for the grinding of sensitive materials such as neodymium iron boron powder. The energy utilization rate of shear grinding is higher than that of impact grinding, and the energy consumption is reduced under the same refinement effect. This ball mill can achieve the effect of multi-stage ball milling through the gradient change of the inner diameter space in the cavity, shortening the grinding time and improving the grinding efficiency.

[0036] During the continuous movement of the ground neodymium iron boron material in the fine grinding chamber, it will contact the rear partition plate 151. The material that meets certain particle size requirements, that is, the particles with a particle diameter smaller than the preset size of the screen on the surface of the rear partition plate 151, will pass through the mesh holes of the rear partition plate 151 and enter the subsequent discharge chamber to wait for discharging. The larger particle neodymium iron boron material that fails to pass through the rear partition plate 151 will continue to stay in the fine grinding chamber and be repeatedly sheared and ground under the continuous action of the grinding balls, the outer surface of the cylinder 14 and the inner wall of the ball milling cylinder 13 until it reaches the required particle size and is discharged through the rear partition plate 151.

[0037] The process of feeding the neodymium iron boron alloy ingot: The outer surface of the fixed plate 23 is fitted with the outer surface of the rear partition plate 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 milling cylinder 13 rotates, relative movement occurs between the two. Among them, grid holes 231 are provided at other positions on the fixed plate 23 except for the range where the eccentric cylinder 241 is located. When the screen on the surface of the rear partition plate 151 coincides with the grid holes 231 of the fixed plate 23, the powdered neodymium iron boron material enters the feeding chamber.

[0038] The left side of the outer circumferential surface of the eccentric cylinder 241 is the farthest from the inner wall surface of the ball mill cylinder 13, and the right side of the outer circumferential surface of the eccentric cylinder 241 is the closest to the inner wall surface of the ball mill cylinder 13. From the fine grinding chamber to the blanking chamber, most of the neodymium iron boron powder enters the lower part of the crescent-shaped space formed by the inner wall of the ball mill cylinder 13 and the eccentric cylinder 241 from the lower part in the circumferential direction. As the ball mill cylinder 13 rotates continuously, the support plate 242 moves synchronously with the ball mill cylinder 13 through the groove body. Among them, the support plate 242 can swing at a small angle in the groove body, so that it can contact the inner wall of the notch 2412 at different angles and is used to drive the eccentric cylinder 241 to rotate. Generally, it is in a relatively static state.

[0039] There are two support plates 242 arranged in a circumferential array around the axis of the ball mill cylinder 13. The support plates 242 rotate clockwise synchronously with the ball mill cylinder 13. The outer ends of the support plates 242 penetrate into the inside of the eccentric cylinder 241 through the notch 2412 (one side of the support plate 242 is attached to the outer surface of the fixed plate 23, and the other side of the support plate 242 is attached to 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.

[0040] In the initial state, the support plate 242 is located on the right side of the ball mill cylinder 13. At this time, the outer end of the support plate 242 penetrates through the notch 2412, and most of the outer end enters the inside of the eccentric cylinder 241. As the ball mill cylinder 13 continues to rotate clockwise, the distance between the side of the support plate 242 close to the axis of the ball mill cylinder 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 surrounded by the inside of the eccentric cylinder 241 is the inner cavity, and the cavity surrounded by the outer circumferential surface of the eccentric cylinder 241 and the inner circumferential wall of the ball mill cylinder 13 is the crescent-shaped cavity). Since the material entering from the fine grinding chamber first comes to the inside of the crescent-shaped cavity, the support plate 242 is always connected to the ball mill cylinder 13 and the eccentric cylinder 241. When the support plate 242 gradually moves from the right end clockwise to the bottom end and then to the left end, the support plate 242 will drive the neodymium iron boron powder at the bottom to flip upward.

[0041] 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.

[0042] 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.

[0043] During this process, due to the certain magnetism of the NdFeB material, the fine powder may adsorb and agglomerate to block the sieve holes 2411. The eccentric cylinder 241 is relatively thin in practical applications, and the length of the through column 264 is much greater than the thickness of the eccentric cylinder 241. The toothed ring 267 is fixedly connected to the inner wall surface of the eccentric cylinder 241 and rotates synchronously with the ball milling cylinder 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 the rotation of the toothed ring 267, relative movement will occur with the gear 266 rotating on the outer surface of the fixed frame 261, and the gear 266 will be driven to rotate on the outer surface of the support cylinder 25. Initially, 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, and the through column 264 is in a contracted state (the through column 264 is preferably made of non-magnetic stainless steel to avoid adsorbing NdFeB powder) and does not contact the inner wall of the eccentric cylinder 241. In the initial state, the eccentric distance on the left side (the side close to the through column 264) of the eccentric roller 265 is small, and the eccentric distance on the right side of the eccentric roller 265 is large.

[0044] When the toothed ring 267 drives the gear 266 to rotate on the outer surface of the support cylinder 25, the axis line of the gear 266 coincides with the axis of the eccentric roller 265. Under the action of the gear 266, the eccentric cylinder 241 makes a rotational movement, driving the side with a larger eccentric distance on the right side of the eccentric roller 265 to move closer to the through column 264, squeezing the connecting plate 263 to move towards the fixed frame 261. The elastic member 262 is elastically deformed under the extrusion, and the through column 264 moves synchronously and penetrates the sieve holes 2411 inside the eccentric cylinder 241, realizing the cleaning effect on the sieve holes 2411. A plurality of sieve holes 2411 are provided in the circumferential direction of the eccentric cylinder 241. The toothed ring 267 rotates synchronously with the eccentric cylinder 241. Every time the eccentric cylinder 241 moves from one sieve hole 2411 in the radial direction to the next sieve hole 2411, it will drive the through column 264 to extend and retract from the sieve hole 2411 once to complete the cleaning. When the support frame 21 moves to the position where the through column 264 is located, the through column 264 will also extend to the position of the through hole inside the support frame 21 to avoid collision.

[0045] In summary, the ball milling equipment has the following advantages: Advantage 1: The inside of the ball milling cylinder 13 is divided into three chamber (coarse crushing chamber, fine grinding chamber, and blanking chamber), which can realize the classification grinding of materials, realize the gradient grinding from the coarse grinding area to the fine grinding area, with a small deviation in the average particle size distribution, shortened grinding time, and is beneficial to improving production efficiency.

[0046] Advantage 2: Inside the fine grinding chamber (between the front partition 15 and the rear partition 151), the grinding balls perform circular rotational motion within the annular gap between the column 14 and the inner wall of the ball mill cylinder 13. The rotation of the column 14 drives the dialing plate 142 to periodically turn over the material, enabling the flaky neodymium iron boron material to be evenly stressed, and solving the problems of excessive grinding at the edges and insufficient grinding in the center of traditional ball milling equipment. Each group of dialing plates 142 (multiple arranged in a circular array) rotates with the column 14, and adjacent two groups are staggered. They drive the material to turn over on the left side and contract on the right side (fitting the surface of the column 14) to make the material slide naturally, realizing that the material and the grinding balls can rub and grind every time they rotate one week, and improving the dispersion efficiency of the agglomerates.

[0047] Advantage 3: In the feeding chamber, the support plate 242 is linked with the ball mill cylinder 13 through the groove body, and realizes swinging by using the geometric constraint of the notch 2412 of the eccentric cylinder 241, without an additional power source, and reducing the energy consumption compared with traditional vibration screening. The eccentric cylinder 241 and the inner wall of the ball mill cylinder 13 form a crescent-shaped cavity that is wider on the left and narrower on the right. After the material enters from below, when it is driven by the support plate 242 to the wide gap on the left and continues to rotate with the rotation of the ball mill cylinder 13, the larger particles stay on the outer surface of the eccentric cylinder 241, and the fine particles that meet the requirements pass through the sieve holes 2411 and enter the inner cavity for feeding. When the large particles that do not pass through the sieve holes 2411 rotate with the eccentric cylinder 241 to the narrow gap on the right, they are subjected to the extrusion and shear force between the outer surface of the eccentric cylinder 241 and the inner wall of the ball mill cylinder 13, and the pressure is relatively large, similar to the rolling effect of two rollers, further crushing the neodymium iron boron particles to meet the standard, and screening the extruded material again until it completely meets the standard and falls onto the discharge plate 22 to complete the feeding, thus completing the cyclic screening to ensure the particle size of the material after ball milling during feeding.

[0048] Advantage 4: When the eccentric cylinder 241 rotates, the toothed ring 267 drives the gear 266 to drive the eccentric roller 265 to swing, squeezing the elastic member 262 to make the through column 264 periodically insert into the sieve holes 2411 to remove the magnetic fine powder agglomerates adsorbed on the sieve holes 2411. The cleaning member 26 can prevent the sieve holes 2411 from being blocked and ensure the continuity of the screening process.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and 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 embodiments of the present invention.

Claims

1. A NdFeB powder ball milling cavity assembly based on cavity variable 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 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).

2. A neodymium iron boron powder ball milling cavity assembly based on cavity variable 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. A NdFeB powder ball milling cavity assembly based on cavity variable 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. A neodymium iron boron powder ball milling cavity assembly based on cavity variable diameter gradient grinding according to claim 1, characterized in that: 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). 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 from the inner wall surface of the ball mill cylinder (13). A cleaning member (26) for cleaning the sieve hole (2411) is provided inside the eccentric cylinder (241).

5. A NdFeB powder ball milling cavity assembly based on cavity variable diameter gradient grinding according to claim 4, characterized in that: A notch (2412) is provided inside the eccentric cylinder (241), and the ball mill cylinder (13) is provided with a support plate (242) via a groove body provided on the inner surface of its circumference. The outer surface of the support plate (242) fits in contact with the inner wall surface of the notch (2412), and two support plates (242) are provided and circumferentially distributed inside the ball mill cylinder (13).

6. A NdFeB powder ball milling cavity assembly based on cavity variable diameter gradient grinding according to claim 4, characterized in that: The cleaning member (26) includes a fixed frame (261). One side of the fixed frame (261) is fixedly connected to one side of the fixed plate (23) close to the support plate (242). The fixed frame (261) is connected with a connecting plate (263) through an elastic member (262) arranged on one side close to the axis of the eccentric cylinder (241). A through column (264) that fits the inner wall surface of the sieve hole (2411) is fixedly connected to the middle of the side of the connecting plate (263) close to the elastic member (262).

7. A NdFeB powder ball milling cavity assembly based on cavity variable diameter gradient grinding according to claim 6, characterized in that: An eccentric roller (265) that fits the side of the connecting plate (263) away from the through column (264) is rotatably connected to the outer surface of the fixed frame (261). A gear (266) is fixedly connected to the outer end of the eccentric roller (265). The side of the gear (266) away from the eccentric roller (265) is rotatably connected to the outer surface of the support cylinder (25). A toothed ring (267) that meshes with the outer surface of the gear (266) is fixedly connected to the inner wall surface of the eccentric cylinder (241).

8. A neodymium iron boron powder ball milling cavity assembly based on cavity variable diameter gradient grinding according to claim 7, characterized in that: The outer end of the through column (264) is designed with a conical surface. A through hole is formed in one side of the support plate (242) close to the through column (264). A grate hole (231) is formed in the interior of the fixed plate (23).

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