Transmission structure of supercritical rotating speed ball mill with center feeding and discharging

Abstract

The invention provides a transmission structure of a supercritical rotating speed ball mill for central feeding and discharging of a ball mill without limit rotating speed limitation, aims to solve the problems that feeding and discharging of an existing ball mill are attached to a wall, and the transmission structure is inconvenient to mount and maintain, and relates to the technical field of industrial powder preparation. The invention discloses a transmission structure of a central feeding and discharging type supercritical rotating speed ball mill. The ball mill comprises a rack, a barrel and a barrel driving mechanism, a feeding hollow shaft is arranged at one end of the cylinder body, a discharging hollow shaft is arranged at the other end of the cylinder body, a feeding guide cylinder is arranged in the feeding hollow shaft, and a discharging guide cylinder is arranged in the discharging hollow shaft; the feeding guide cylinder is fixedly connected with the rack; a feeding center shaft is arranged in the feeding guide cylinder, the discharging guide cylinder is fixedly connected with the rack, a discharging center shaft is arranged in the discharging guide cylinder, and the cylinder body driving mechanism is in transmission connection with one end of the feeding center shaft or one end of the discharging center shaft. The production efficiency of the ball mill is improved.

Description

Technical Field

[0001] This invention relates to the field of industrial powder preparation technology, specifically a transmission structure for a supercritical speed ball mill with central feed and discharge. Background Technology

[0002] Ball mills are a basic type of mechanical grinding equipment, widely used in industries such as metallurgy, building materials, and chemicals, especially in the grinding and production of minerals and cement. The main reasons for the widespread use of ball mills are: 1. Excellent grinding performance, producing near-spherical powder particles with a reasonable particle size distribution; 2. Stable and reliable continuous operation; 3. Large single-unit capacity.

[0003] When the cylinder rotation speed reaches or exceeds the limit (critical) speed, the grinding media and the cylinder remain relatively stationary while rotating with the cylinder, resulting in a "wall-attached" motion. This prevents the material and grinding media from colliding and impacting each other within the ball mill. Therefore, the rotation speed of the rotating cylinder in traditional ball mills is lower than the limit (critical) speed (the rotation speed is generally designed at 70-80% of the critical speed). Due to the limitation of the limit speed, low-speed, high-torque transmission devices are standard and typical features of traditional ball mills to ensure large-scale industrial production capacity.

[0004] To meet the low-speed, high-torque requirements of traditional ball mills, the main drive of traditional ball mills primarily uses edge drive. The main disadvantages of edge drive in traditional ball mills are: bulky transmission device, large reduction ratio, low transmission efficiency, poor lubrication and easy wear in open (last stage) transmissions, high installation requirements (the meshing accuracy of the large and small gear pairs relies on on-site installation and adjustment), large footprint, and relatively high manufacturing costs. The large gear of a traditional edge-drive ball mill has dimensions far exceeding the outer diameter of the cylinder. Due to manufacturing costs and transportation limitations, it is difficult to manufacture a closed transmission; therefore, it can only be designed as an open transmission. For example, in a ball mill with a cylinder size of φ1.8m*7m, the outer diameter of the large gear exceeds φ3m, nearly twice the outer diameter of the cylinder.

[0005] With technological advancements, it has become possible to improve ball mill efficiency by breaking through the limiting (critical) speed range. For example... Figure 1As shown: The applicant has applied for a ball mill with application number CN2024108028206, which allows material to be fed and discharged from the center of the cylinder. The mill includes a frame 1 and a cylinder 2. One end of the cylinder 2 is provided with a hollow feed shaft 21, and the other end is provided with a hollow discharge shaft 22. The cylinder 2 is rotatably mounted on the frame 1 so that the material around the cylinder 2 can rotate around its own axis. The mill also includes at least one impact mechanism 3 installed inside the cylinder 2 and arranged around the axis of the cylinder 2 so that it can revolve with the cylinder 2 around its axis. The impact mechanism 3 includes a planetary shaft 31, which is arranged along the axial direction of the cylinder 2. The planetary shaft 31 is rotatably connected to the cylinder 2 so that the planetary shaft 31 can rotate around its own axis, i.e., rotate on its own axis. The planetary shaft 31 is provided with an impact plate 33 for scraping the material attached to the wall inside the cylinder 2. In the figure, the planetary shaft 31 is driven by a fixed gear 4, which is located at one end of the cylinder 2 and arranged coaxially with the cylinder 2. The fixed gear 4 is mounted and fixed on the frame 1. The end of the planetary shaft 31 near the fixed gear 4 extends out of the cylinder 2 and is provided with a planetary gear 5 that meshes with the fixed gear 4 to drive the planetary shaft 31 to rotate around its own axis. During the rotation of the cylinder, the ball mill drives the planetary shaft 31 to rotate around the axis of the cylinder 2, while simultaneously achieving its own rotation around its own axis through the planetary gear 5 and the fixed gear 4. During the rotation of the planetary shaft 31, the impact plate 33 rotates together. During the rotation of the impact plate 33, the wall-attached material and grinding media in the trajectory area of ​​the impact plate 33 are scraped off and impacted, thereby impacting and removing the wall-attached material and grinding media in the nearby area, thus eliminating the wall-attached material and enabling the material and grinding media to effectively impact each other inside the cylinder 2, achieving grinding at speeds exceeding the limit.

[0006] When a ball mill is no longer limited by its maximum speed, the cylinder rotation speed can be increased several times over. Under the same transmission power, the torque of the cylinder drive device is reduced several times, allowing for a significant reduction in the size and weight of the main drive unit. This creates conditions for changing the traditional ball mill transmission structure to overcome the inconvenience of installation and maintenance. However, with the ball mill no longer limited by its maximum speed, as the cylinder rotation speed increases, exceeding the maximum speeds of the feed and discharge hollow shafts can lead to material adhesion to the walls, causing difficulties in feeding and discharging during operation, easily resulting in material blockage, and preventing continuous production, thus affecting the ball mill's production efficiency. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a transmission structure for a supercritical speed ball mill with center feed and discharge that is not limited by the ball mill's maximum speed, so as to solve the problems of feed and discharge wall adhesion and inconvenient installation and maintenance of the existing ball mill transmission structure.

[0008] The technical solution adopted by the present invention to solve its technical problem is: a transmission structure for a supercritical speed ball mill with center inlet and outlet, the ball mill including a frame, a cylinder and a cylinder drive mechanism; the cylinder is rotatably connected to the frame, one end of the cylinder is provided with a coaxial feed hollow shaft, the other end is provided with a coaxial discharge hollow shaft, the feed hollow shaft is provided with a feed guide cylinder rotatably engaged with the feed hollow shaft, and the discharge hollow shaft is provided with a discharge guide cylinder rotatably engaged with the discharge hollow shaft;

[0009] The outer end of the feed guide tube extends out to the feed hollow shaft and is fixedly connected to the frame; the feed guide tube is provided with a feed center shaft that is coaxial with and rotatable, the feed center shaft is fixedly connected to the tube body, and the feed center shaft is provided with a feed pushing structure that cooperates with the inner wall of the feed guide tube to push the material in the feed guide tube into the tube body.

[0010] The outer end of the discharge guide tube extends out to the discharge hollow shaft and is fixedly connected to the frame. The discharge guide tube is provided with a discharge center shaft that is coaxial with and rotatable. The discharge center shaft is fixedly connected to the tube body. The discharge center shaft is provided with a reverse pushing structure that cooperates with the inner wall of the discharge guide tube to push the sinking material in the discharge guide tube into the tube body.

[0011] The cylinder driving mechanism is connected to one end of the feeding center shaft or the discharging center shaft to drive the cylinder to rotate via the feeding center shaft or the discharging center shaft.

[0012] Furthermore, the cylinder driving mechanism is connected to one end of the discharge center shaft to drive the cylinder to rotate via the discharge center shaft.

[0013] Furthermore, the feeding and pushing structure includes at least one feeding spiral belt wound around the feeding central shaft, the feeding spiral belt and the feeding central shaft are provided with a gap, and the feeding spiral belt is fixed on the feeding central shaft by a first support.

[0014] Furthermore, the reverse pushing structure includes at least one reverse pushing spiral belt wound around the discharge center shaft, with a gap between the reverse pushing spiral belt and the discharge center shaft, the reverse pushing spiral belt being fixed to the discharge center shaft by a second support, and the rotation direction of the reverse pushing spiral belt being opposite to that of the feeding spiral belt.

[0015] Furthermore, a hollow feed transition section is provided between the feed hollow shaft and the inner cavity of the cylinder. The inner cavity of the feed transition section has a frustum-shaped structure, and the small end of the feed transition section is connected to the inner end of the feed hollow shaft.

[0016] Furthermore, a hollow discharge transition section is provided between the inner cavity of the cylinder and the discharge hollow shaft. The inner cavity of the discharge transition section has a frustum-shaped structure, and the small end of the discharge transition section is connected to the inner end of the discharge hollow shaft.

[0017] Furthermore, the inner end of the feeding spiral belt is provided with a feeding spiral belt extension section that extends beyond the inner end of the feeding guide cylinder, and the length of the feeding spiral belt extension section is preferably 10-20mm.

[0018] Furthermore, the inner end of the reverse thrust spiral belt is provided with a reverse thrust spiral belt extension section that extends beyond the inner end of the feed guide cylinder, and the length of the reverse thrust spiral belt extension section is preferably 10-20mm.

[0019] Furthermore, the inner end of the feed guide tube is provided with a feed extension section that extends beyond the inner end of the feed hollow shaft, and the length of the feed extension section is preferably 5 to 10 mm.

[0020] Furthermore, the inner end of the discharge guide tube is provided with a discharge extension section that extends beyond the inner end of the discharge hollow shaft, and the length of the discharge extension section is preferably 5 to 10 mm.

[0021] The beneficial effects of this invention are:

[0022] The present invention provides a transmission structure for a supercritical speed ball mill with center feed and discharge, which solves the problem of material adhering to the wall during ball mill feeding and discharging, ensures continuous production of the ball mill at supercritical speed, improves the production efficiency of the ball mill, and makes feeding and discharging of the ball mill more convenient, and the feeding and discharging structure is not easily worn or damaged.

[0023] The cylinder is driven by a cylinder drive mechanism that is connected to one end of the feed center shaft or the discharge center shaft. This method simplifies the drive structure and makes installation and maintenance easier. Attached Figure Description

[0024] Figure 1 This is a structural diagram of existing technology;

[0025] Figure 2 This is a schematic diagram of a ball mill structure employing the transmission structure of the present invention;

[0026] Figure 3 This is a schematic diagram of a feeding and pushing structure;

[0027] Figure 4 yes Figure 3 Sectional view along AA;

[0028] Figure 5 yes Figure 3 Enlarged view of point B;

[0029] Figure 6This is a schematic diagram of the reverse push structure;

[0030] Figure 7 yes Figure 6 Enlarged view of point C;

[0031] Figure 8 This is a schematic diagram of a feeding and pushing structure;

[0032] The diagram shows: frame 1, cylinder 2, impact mechanism 3, fixed gear 4, planetary gear 5, cylinder drive mechanism 6, feed guide cylinder 7, discharge guide cylinder 8, feed hollow shaft 21, discharge hollow shaft 22, feed transition section 23, discharge transition section 24, planetary shaft 31, impact plate 33, feed center shaft 71, feed spiral belt 72, first support 73, feed extension section 74, discharge negative pressure sealing channel 75, feed port 76, arc plate 77, first rib 78, discharge center shaft 81, reverse thrust spiral belt 82, second support 83, discharge extension section 84, discharge negative pressure sealing channel 85, discharge port 86, second rib 87, feed spiral belt extension section 721, and reverse thrust spiral belt extension section 821. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] like Figure 1 , Figure 2As shown, the ball mill of the present invention includes a frame 1 and a cylinder 2. One end of the cylinder 2 is provided with a feed hollow shaft 21, and the other end is provided with a discharge hollow shaft 22. The cylinder 2 is rotatably mounted on the frame 1. The ball mill of the present invention also includes a planetary shaft rotation drive mechanism and at least one impact mechanism 3 installed inside the cylinder 2 and arranged around the axis of the cylinder 2 so as to revolve with the cylinder 2 around the axis of the cylinder 2. The impact mechanism 3 includes a planetary shaft 31, which is arranged along the axial direction of the cylinder 2. The planetary shaft 31 is rotatably connected to the cylinder 2 so that the planetary shaft 31 can rotate around its own axis, i.e., rotate on its own axis. The planetary shaft 31 is provided with an impact plate 33 for scraping the material adhering to the wall inside the cylinder 2. The planetary shaft rotation drive mechanism can be a motor. In the figure, the planetary shaft rotation drive mechanism includes a fixed gear 4, which is located at one end of the cylinder 2 and arranged coaxially with the cylinder 2. The fixed gear 4 is mounted and fixed on the frame 1. The end of the planetary shaft 31 near the fixed gear 4 extends out of the cylinder 2 and is equipped with a planetary gear 5 that meshes with the fixed gear 4 to drive the planetary shaft 31 to rotate around its own axis. The fixed gear 4 can be an external gear or an internal gear. During the rotation of the cylinder, the ball mill drives the planetary shaft 31 to rotate around the axis of the cylinder 2, while simultaneously achieving rotation around its own axis through the planetary gear 5 and the fixed gear 4. During the rotation of the planetary shaft 31, the impact plate 33 rotates as well. During the rotation of the impact plate 33, it scrapes and impacts the wall-attached material and grinding media within its trajectory area, thereby impacting and removing wall-attached material and grinding media in the surrounding area, thus eliminating wall-attached material and ensuring effective impact between the material and grinding media within the cylinder 2, achieving grinding at speeds exceeding the limit (critical) speed.

[0035] To address the issue of material adhering to the walls of the ball mill as the cylinder rotation increases after exceeding its speed limit, especially when the cylinder speed surpasses the limit speeds of the feed and discharge hollow shafts 21 and 22, this paper proposes a solution. Furthermore, since the ball mill is no longer limited by its speed limit, the cylinder speed can be increased several times over. Under the same transmission power, the torque of the cylinder drive device is reduced several times, allowing for a significant reduction in the size and weight of the main drive unit. This creates conditions for modifying the traditional ball mill transmission structure to overcome the inconvenience of installation and maintenance difficulties of the existing structure. Therefore, as such... Figure 2 As shown, this invention incorporates a central continuous feeding structure and a discharge structure on the ball mill, and improves the transmission structure. Specifically, the central continuous feeding structure and the discharge structure are as follows: Figure 2As shown, the hollow feed shaft 21 is equipped with a feed guide cylinder 7 that rotatably engages with the hollow feed shaft 21, and the hollow discharge shaft 22 is equipped with a discharge guide cylinder 8 that rotatably engages with the hollow discharge shaft 22; the outer end of the feed guide cylinder 7 extends out of the hollow feed shaft 21 and is fixedly connected to the frame 1; the feed guide cylinder 7 is equipped with a feed center shaft 71 that is coaxial with and rotatable, so that the feed center shaft 71 can rotate around its own axis within the feed guide cylinder 7; the feed center shaft 71 is fixedly connected to the cylinder body 2, and the feed center shaft 71 is equipped with a feed pushing structure that engages with the inner wall of the feed guide cylinder 7 to push the material in the feed guide cylinder 7 into the cylinder body 2; the discharge... The outer end of the guide tube 8 extends out to the discharge hollow shaft 22, which is fixedly connected to the frame 1. The discharge guide tube 8 is provided with a discharge center shaft 81 that is coaxial with and rotatable, so that the discharge center shaft 81 can rotate around its own axis inside the discharge guide tube 8. The discharge center shaft 81 is fixedly connected to the cylinder 2. The discharge center shaft 81 is provided with a reverse pushing structure that cooperates with the inner wall of the discharge guide tube 8 to push the sinking material in the discharge guide tube 8 into the cylinder 2. The transmission structure is as follows: the cylinder driving mechanism 6 is connected to one end of the feeding center shaft 71 or the discharge center shaft 81 to drive the cylinder 2 to rotate through the feeding center shaft 71 or the discharge center shaft 81.

[0036] The fixed connection in this invention can adopt various conventional fixed connection methods such as bolt connection and welding.

[0037] The feed inlet 76 of the feed guide cylinder 7 can be located on the end face or side face of the feed guide cylinder 7, and the discharge outlet 86 of the discharge guide cylinder 8 can also be located on the end face or side face of the discharge guide cylinder 8. In this invention, the feed inlet 76 of the feed guide cylinder 7 is located on the upper side face of the feed guide cylinder 7, and the discharge outlet 86 of the discharge guide cylinder 8 is located on the upper side face of the discharge guide cylinder 8 (see...). Figure 2 ).

[0038] The cylinder drive mechanism 6 generally uses an electric motor.

[0039] In the embodiments of the present invention, the cylinder 2 is rotatably connected to the frame via the discharge hollow shaft 22 and the feed hollow shaft 21.

[0040] When the ball mill of the present invention is in operation, the cylinder is driven to rotate by the cylinder drive mechanism 6, and the air inlet of the pneumatic conveying device is connected to the discharge port of the discharge guide cylinder 8 to evacuate the air inside the cylinder 2 and generate a feeding airflow. Since both the feeding center shaft 71 and the discharge center shaft 81 are fixed on the cylinder, during the process of the cylinder drive mechanism 6 driving the cylinder to rotate through the central shaft connected to it, it will drive the other central shaft to rotate together through the cylinder, thereby causing the feeding push structure and the reverse push structure to rotate.

[0041] like Figure 2 , Figure 3 and Figure 6 As shown, the feeding and discharging principle of the ball mill is as follows: During material processing, the material enters the feeding guide cylinder 7 through the inlet 76 and is pushed into the cylinder body by the rotating feeding push structure. Simultaneously, the feeding guide cylinder 7 continuously receives the required amount of air for discharge. Inside the cylinder 2, the material is continuously crushed and ground. During this crushing and grinding process, fine powder is continuously carried into the discharge guide cylinder 8 as an air-powder mixture by the air at a certain flow rate inside the cylinder 2, and discharged through the discharge outlet 86. During the grinding process inside the cylinder 2, a small portion of material and grinding media near the feeding direction may also enter the feeding guide cylinder 7 due to collision. In the same principle, it is pushed back into the cylinder 2 by the central feeding structure. Similarly, a small portion of coarser material and grinding media near the discharge direction may also enter the discharge guide cylinder 8 due to collision. In the same principle, it is pushed back into the cylinder 2 by the reverse pushing structure. During the discharge process, a small portion of relatively coarse-diameter powder will separate and settle to the lower part of the discharge guide cylinder 8 under the influence of gravity and other factors. This deposited powder is then pushed into the cylinder by the rotating reverse pushing structure. Therefore, this ball mill is clearly suitable for dry production. Based on factors such as reduced energy consumption, reduced powder selection (the powder leaving the mill generally needs to be separated into qualified powders) circulation ratio, and reduced dust-containing air purification and environmental protection treatment, it is particularly suitable for the production of dry ultrafine powders.

[0042] In this invention, the ball mill's cylinder does not rotate during operation, instead driving the feed guide cylinder and discharge guide cylinder to rotate. Instead, it drives the feed pushing structure and the reverse pushing structure to rotate. Therefore, the problem of material adhering to the walls during feeding and discharging is eliminated, and the issue is transformed into a simple accumulation problem. This facilitates pushing the material in the feed guide cylinder and the settled material in the discharge guide cylinder into the drum. During the rotation of the feed pushing structure, the material adhering to the walls in the feed guide cylinder 7 is pushed into the drum. Similarly, during the rotation of the reverse pushing structure, coarser material settled on the inner wall of the discharge guide cylinder 8 is pushed back into the drum. Therefore, this invention solves the problem of material adhering to the walls when the mill exceeds its maximum speed, especially when exceeding the maximum speeds of the feed and discharge hollow shafts. This ensures continuous production even at speeds exceeding the maximum limits, improves the mill's production efficiency, and makes feeding and discharging more convenient, with the feeding and discharging structures less prone to wear and damage. In addition, the cylinder is driven by a cylinder drive mechanism that is connected to one end of the feed center shaft 71 or the discharge center shaft 81, which makes the drive structure simpler and easier to install and maintain.

[0043] In this invention, preferably, the cylinder drive mechanism 6 is connected to one end of the discharge center shaft 81 for driving the cylinder 2 to rotate via the discharge center shaft 81. To meet strength requirements, the diameter of the center shaft connected to the cylinder drive mechanism 6 is relatively large. Since the material is discharged in the form of an air-powder mixture, connecting one end of the discharge center shaft 81 to the cylinder drive mechanism 6 has a relatively small impact on the feeding and discharging of the ball mill.

[0044] Specifically, such as Figure 3 As shown, the feeding and pushing structure of this invention includes at least one feeding spiral belt 72 wound around the feeding central shaft 71. A gap is provided between the feeding spiral belt 72 and the feeding central shaft 71 to allow airflow and material to pass through and enter the cylinder. The feeding spiral belt 72 is fixed to the feeding central shaft 71 by a first support 73. Since the feeding spiral belt 72 pushes the material in the feeding guide cylinder 7 into the cylinder 2 driven by the cylinder through the feeding central shaft 71, the specific rotation direction of the feeding spiral belt 72 should be set according to the rotation direction of the cylinder during operation. Specifically, when the cylinder rotates clockwise, the feeding spiral belt rotates left-hand; when the cylinder rotates counterclockwise, the feeding spiral belt rotates right-hand. The cylinder 2 is driven by a cylinder driving mechanism, and the rotation direction of the cylinder is determined by the cylinder driving mechanism. Figure 8 As shown, in some embodiments, the feeding and pushing structure also adopts a structure in which multiple arc-shaped plates 77 are set on the feeding center shaft 71, and the arc-shaped plates 77 are inclined relative to the axis of the feeding center shaft 71. The inclination direction of the arc-shaped plates 77 is also set according to the rotation direction of the cylinder during operation, and the specific principle is the same as the principle described above, and will not be described in detail again.

[0045] Specifically, such as Figure 6 As shown, the reverse pushing structure includes at least one reverse pushing spiral belt 82 wound around the discharge center shaft 81. A gap is provided between the reverse pushing spiral belt 82 and the discharge center shaft 81 to facilitate the passage and outflow of airflow and material. The reverse pushing spiral belt 82 is fixed to the discharge center shaft 81 by a second support 83. Since the reverse pushing spiral belt 82 pushes the sinking material in the discharge guide cylinder 8 into the cylinder 2 driven by the cylinder through the discharge center shaft 81, the specific rotation direction of the reverse pushing spiral belt 82 should also be set according to the rotation direction of the cylinder during operation. Specifically, the rotation direction of the reverse pushing spiral belt 82 is opposite to that of the feeding spiral belt 72; that is, when the cylinder rotates clockwise, the reverse pushing spiral belt rotates right-handed; when the cylinder rotates counterclockwise, the reverse pushing spiral belt rotates left-handed. In some embodiments, the reverse pushing structure also adopts a structure with multiple arc-shaped plates on the discharge center shaft, the arc-shaped plates being inclined relative to the axis of the discharge center shaft.

[0046] The feed hollow shaft 21 can transition directly at a 90° angle to the inner wall of the cylinder, and the inner wall of the cylinder can also transition directly at a 90° angle to the discharge hollow shaft 22. For example... Figure 2 As shown, in this invention, a hollow feed transition section 23 is provided between the feed hollow shaft 21 and the inner cavity of the cylinder 2. The inner cavity of the feed transition section 23 has a frustoconical structure, and the small end of the feed transition section 23 is connected to the inner end of the feed hollow shaft 21. A hollow discharge transition section 24 is provided between the inner cavity of the cylinder 2 and the discharge hollow shaft 22. The inner cavity of the discharge transition section 24 also has a frustoconical structure, and the small end of the discharge transition section 24 is connected to the inner end of the discharge hollow shaft 22. In this way, after the material passes through the feed guide cylinder 7, it will first slide along the inclined surface formed by the inner cavity surface of the feed transition section 23 before entering the cylinder, which allows the incoming material to fall at the very front of the cylinder, which is beneficial for material processing. With the discharge transition section 24 in place, smaller particles can more easily flow out of the discharge guide tube 8 under the action of airflow, which is beneficial for material discharge. It also facilitates the backflow of coarser materials pushed by the reverse pushing structure back down the inclined surface formed by the inner cavity of the discharge transition section and into the cylinder. Understandably, the inner cone angles of the feed transition section 23 and the discharge transition section 24 should allow materials to slide down into the cylinder during rotation without adhering to it. Generally, the inner cone angles of the feed transition section 23 and the discharge transition section 24 are greater than 80°. However, if the inner cone angles of the feed transition section 23 and the discharge transition section 24 are too large, the feed and discharge pushing mechanisms will inevitably grow, leading to negative consequences such as reduced structural strength, increased manufacturing difficulty, and severe wear and tear from collisions with the material. Therefore, the preferred value for the inner cone angles of the feed transition section 23 and the discharge transition section 24 is 90°.

[0047] To facilitate material feeding and discharging as well as material processing, in this invention, preferably, the feeding center shaft 71 is fixed to the inner wall of the feeding transition section 23 by the first stiffener 78 to achieve a fixed connection with the cylinder, and the discharging center shaft 81 is fixed to the inner wall of the discharging transition section 24 by the second stiffener 87 to achieve a fixed connection with the cylinder.

[0048] The inner end of the feed spiral 72 can extend inward beyond the inner end of the feed guide cylinder 7, or it can remain within the inner end of the feed guide cylinder 7. For example... Figure 5 As shown, to facilitate feeding, the inner end of the feeding spiral ribbon 72 is provided with a feeding spiral ribbon extension section 721 that extends beyond the inner end of the feeding guide cylinder 7. The length of the feeding spiral ribbon extension section 721 can be set as needed, but if the feeding spiral ribbon extension section 721 is too long, it will reduce the structural strength of the feeding spiral ribbon extension section 721 and increase its collision and wear with the material grinding body inside the cylinder 2. Therefore, in this invention, the length of the feeding spiral ribbon extension section 721 is preferably 10-20 mm.

[0049] To facilitate pushing the sinking material into the drum, such as Figure 7 As shown, in this invention, the inner end of the reverse thrust spiral belt 82 is provided with a reverse thrust spiral belt extension section 821 extending beyond the inner end of the feed guide cylinder 7. The length of the reverse thrust spiral belt extension section 821 can be set as needed, but if the reverse thrust spiral belt extension section 821 is too long, it will reduce the structural strength of the reverse thrust spiral belt extension section 821 and increase its collision and wear with the material grinding body inside the cylinder 2. Therefore, the length of the reverse thrust spiral belt extension section 821 in this invention is preferably 10-20 mm.

[0050] In this invention, to prevent dust and other particles inside the cylinder from entering the gap between the feed guide cylinder 7 and the feed hollow shaft 21 and affecting the rotation of the cylinder, a negative pressure sealing channel 85 is formed between the outer wall of the feed guide cylinder 7 and the inner wall of the feed hollow shaft 21 to introduce outside air into the cylinder 2. That is, one end of the negative pressure sealing channel 85 communicates with the outside, and the other end communicates with the inner cavity of the cylinder. This allows outside air to enter the cylinder through the negative pressure channel 85 under the influence of the negative pressure inside the cylinder, thereby preventing dust and other particles inside the cylinder from entering the gap between the feed guide cylinder 7 and the feed hollow shaft 21. The gap between the outer wall of the feed guide cylinder 7 and the inner wall of the feed hollow shaft 21 is generally 1–5 mm. However, if this gap is too small, it will increase the manufacturing precision and cost of the feed hollow shaft 21 and the feed guide cylinder 7; if the gap is too large, large particles can easily enter the gap, affecting the negative pressure airflow seal. Therefore, the preferred thickness in this invention is 2 to 3 mm.

[0051] Similarly, to prevent dust and other particles inside the cylinder from entering the gap between the discharge guide cylinder 8 and the discharge hollow shaft 22 and affecting the rotation of the cylinder, a negative pressure sealing channel 85 is formed between the outer wall of the discharge guide cylinder 8 and the inner wall of the discharge hollow shaft 22 to introduce outside air into the cylinder 2. That is, one end of the negative pressure sealing channel 85 communicates with the outside, and the other end communicates with the inner cavity of the cylinder. In this way, the negative pressure inside the cylinder allows outside air to enter the cylinder through the negative pressure sealing channel 85, thereby preventing dust and other particles inside the cylinder from entering the gap between the discharge guide cylinder 8 and the discharge hollow shaft 22. The gap between the outer wall of the discharge guide tube 8 and the inner wall of the discharge hollow shaft 22 is generally 1 to 5 mm. However, if the gap is too small, it will increase the manufacturing precision and cost of the feed hollow shaft 21 and the feed guide tube 7. If the gap is too large, large particles will easily enter the gap and affect the negative pressure airflow seal. In this invention, the gap is preferably 2 to 3 mm.

[0052] The inner end of the feed guide tube 7 can extend inward beyond the inner end of the feed hollow shaft 21, or it can extend beyond the inner end of the feed hollow shaft 21. For example... Figure 5As shown, to facilitate feeding, the inner end of the feeding guide cylinder 7 is provided with a feeding extension section 74 that extends beyond the inner end of the feeding hollow shaft 21. That is, the inner end of the feeding guide cylinder 7 exceeds the inner end of the feeding hollow shaft 21. The length of the feeding extension section 74 can be arbitrarily set as needed. However, in practice, it has been shown that if the feeding extension section 74 is too long, especially after the feeding transition section 23 is provided, the material is prone to getting stuck between the stationary feeding guide cylinder 7 and the rotating feeding transition section 23, causing strong frictional wear damage to the feeding guide cylinder 7 and the feeding transition section 23; if the feeding extension section 74 is too short, it will damage the negative pressure sealing air intake gap channel between the feeding guide cylinder 7 and the feeding hollow shaft 21. Therefore, in this invention, the length of the feeding extension section 74 is preferably 5 to 10 mm.

[0053] The inner end of the discharge guide tube 8 can extend inward beyond the inner end of the discharge hollow shaft 22, or it can extend beyond the inner end of the discharge hollow shaft 22. For example... Figure 7 As shown, in this invention, the inner end of the discharge guide cylinder 8 is provided with a discharge extension section 84 that extends beyond the inner end of the discharge hollow shaft 22. That is, the inner end of the discharge guide cylinder 8 extends beyond the inner end of the discharge hollow shaft 22. The discharge extension section 84 can be arbitrarily set as needed, but practice shows that if the discharge extension section 84 is too long, especially with the discharge transition section 24, material is easily stuck between the stationary discharge guide cylinder 8 and the rotating discharge transition section 24, causing severe frictional wear and damage to both. Conversely, if the discharge extension section 84 is too short, it will disrupt the negative pressure sealing air inlet gap between the discharge guide cylinder 8 and the discharge hollow shaft 22. Therefore, the preferred length of the discharge extension section 84 in this invention is 5–10 mm.

Claims

1. A transmission structure for a supercritical speed ball mill with center feed and discharge, the ball mill comprising a frame (1), a cylinder (2), and a cylinder drive mechanism (6); the cylinder (2) is rotatably connected to the frame (1), one end of the cylinder (2) is provided with a coaxial feed hollow shaft (21), and the other end is provided with a coaxial discharge hollow shaft (22), characterized in that: The feed hollow shaft (21) is provided with a feed guide cylinder (7) that rotates with the feed hollow shaft (21), and the discharge hollow shaft (22) is provided with a discharge guide cylinder (8) that rotates with the discharge hollow shaft (22). The outer end of the feed guide tube (7) extends out to the feed hollow shaft (21) and is fixedly connected to the frame (1); the feed guide tube (7) is provided with a feed center shaft (71) that is coaxial with and rotatable, the feed center shaft (71) is fixedly connected to the cylinder (2), and the feed center shaft (71) is provided with a feed pushing structure that cooperates with the inner wall of the feed guide tube (7) to push the material in the feed guide tube (7) into the cylinder (2); The outer end of the discharge guide cylinder (8) extends out the discharge hollow shaft (22) and is fixedly connected to the frame (1). The discharge guide cylinder (8) is provided with a discharge center shaft (81) that is coaxial with and rotatable. The discharge center shaft (81) is fixedly connected to the cylinder body (2). The discharge center shaft (81) is provided with a reverse pushing structure that cooperates with the inner wall of the discharge guide cylinder (8) to push the sinking material in the discharge guide cylinder (8) into the cylinder body (2). The cylinder drive mechanism (6) is connected to one end of the feeding center shaft (71) or the discharging center shaft (81) to drive the cylinder (2) to rotate via the feeding center shaft (71) or the discharging center shaft (81).

2. The transmission structure of a center-feed / discharge supercritical speed ball mill as described in claim 1, characterized in that: The cylinder driving mechanism (6) is connected to one end of the discharge center shaft (81) to drive the cylinder (2) to rotate through the discharge center shaft (81).

3. The transmission structure of a supercritical speed ball mill with center feed and discharge as described in claim 1, characterized in that: The feeding and pushing structure includes at least one feeding spiral belt (72) wound around the feeding central shaft (71), with a gap between the feeding spiral belt (72) and the feeding central shaft (71), and the feeding spiral belt (72) is fixed on the feeding central shaft (71) by a first support (73).

4. The transmission structure of a center-feed / discharge supercritical speed ball mill as described in claim 3, characterized in that: The reverse pushing structure includes at least one reverse pushing spiral belt (82) wound around the discharge center shaft (81), with a gap between the reverse pushing spiral belt (82) and the discharge center shaft (81), the reverse pushing spiral belt (82) being fixed on the discharge center shaft (81) by a second support (83), and the rotation direction of the reverse pushing spiral belt (82) being opposite to that of the feeding spiral belt (72).

5. The transmission structure of a center-feed / discharge supercritical speed ball mill as described in claim 1, characterized in that: A hollow feed transition section (23) is provided between the feed hollow shaft (21) and the inner cavity of the cylinder (2). The inner cavity of the feed transition section (23) is a frustoconical structure. The small end of the feed transition section (23) is connected to the inner end of the feed hollow shaft (21).

6. The transmission structure of a center-feed / discharge supercritical speed ball mill as described in claim 1, characterized in that: A hollow discharge transition section (24) is provided between the inner cavity of the cylinder (2) and the discharge hollow shaft (22). The inner cavity of the discharge transition section (24) is a frustoconical structure. The small end of the discharge transition section (24) is connected to the inner end of the discharge hollow shaft (22).

7. The transmission structure of a center-feed / discharge supercritical speed ball mill as described in claim 3, characterized in that: The inner end of the feed spiral belt (72) is provided with a feed spiral belt extension section (721) that extends beyond the inner end of the feed guide cylinder (7), and the length of the feed spiral belt extension section (721) is preferably 10 to 20 mm.

8. The transmission structure of a center-feed / discharge supercritical speed ball mill as described in claim 4, characterized in that: The inner end of the reverse thrust spiral belt (82) is provided with a reverse thrust spiral belt extension section (821) that extends beyond the inner end of the feed guide cylinder (7), and the length of the reverse thrust spiral belt extension section (821) is preferably 10 to 20 mm.

9. The transmission structure of a center-feed / discharge supercritical speed ball mill according to any one of claims 1 to 8, characterized in that: The inner end of the feed guide tube (7) is provided with a feed extension section (74) that extends beyond the inner end of the feed hollow shaft (21), and the length of the feed extension section (74) is preferably 5 to 10 mm.

10. The transmission structure of a center-feed / discharge supercritical speed ball mill according to any one of claims 1 to 8, characterized in that: The inner end of the discharge guide tube (8) is provided with a discharge extension section (84) that extends beyond the inner end of the discharge hollow shaft (22), and the length of the discharge extension section (84) is preferably 5 to 10 mm.

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