Metal powder screening mechanism

Abstract

The present invention relates to the technical field of screening devices, and specifically discloses a metal powder screening mechanism, comprising a vibrating base and a top cover, wherein a plurality of screen frames are installed between the vibrating base and the top cover, and a screen mesh is arranged in the screen frame, and a main shaft is installed at the axis center of the screen frame, and a plurality of fixing rings are coaxially installed on the main shaft, and the middle part of the screen mesh is connected to the fixing ring, and a tensioning ring is installed for lifting on the inner side surface of each screen frame, and the edge of the screen mesh is connected to the screen frame by bypassing the tensioning ring. A plurality of rotating rings are rotatably connected to the main shaft, and a driving mechanism for controlling the rotation of the rotating ring is installed in the main shaft, and a plurality of slide rails are hinged on the rotating ring along its circumferential direction, and an impact ball is arranged in the slide rail. During the screening process, the inclination of the screen mesh is dynamically adjusted. When the material increases, the tensioning ring rises, the main shaft descends, the inclination of the screen mesh decreases, and the speed at which the material is dispersed is slowed down, thereby preventing the material from entering the standby area without being fully screened.

Description

Technical Field

[0001] The present invention relates to the technical field of screening devices, and in particular to a metal powder screening mechanism. Background Art

[0002] Metal additive manufacturing is a rapidly developing emerging technology in the manufacturing sector. With increasing development and maturity, it is now widely used in industries such as aerospace, biomedicine, military, metallurgy, construction, automotive, electronics, jewelry, and molds. Metal powders used in additive manufacturing, as a key raw material, play a crucial role in the development of this technology. Metal powders used in additive manufacturing must meet the following requirements: small particle size, narrow powder distribution, good flowability, and high bulk density. Currently, mainstream powder production technologies produce metal powders with a wide particle size distribution, making them unsuitable for direct use in additive manufacturing. Therefore, the produced powders must be screened using a rotary vibrating screen. A rotary vibrating screen is a high-precision fine powder screening machine with low noise, high efficiency, and a fully enclosed structure, making it suitable for screening and filtering powder materials. The rotary vibrating screen uses an upright motor as the excitation source. Eccentric weights are mounted on the top and bottom of the motor, converting the motor's rotational motion into three-dimensional motion: horizontal, vertical, and tilted. This motion is then transmitted to the screen surface, thereby screening the material.

[0003] Chinese patent document CN111530739B discloses a high-efficiency rotary vibrating screen for screening germ powder, relating to the field of screening equipment. The key technical features of the device are as follows: it comprises a base and several screen frames, a shock-absorbing spring connected between the screen frames and the base, a vibrating motor connected to the screen frame near the base, several screen meshes arranged sequentially from top to bottom within the screen frames, a feed inlet at the top of the screen frames, and discharge outlets on the side walls of the screen frames. The screen frames comprise an upper frame, a lower frame, and a bracket, the two ends of the bracket being connected to the upper and lower frames, respectively. A gear ring is rotatably connected between the upper and lower frames, and a gear meshing with the gear ring is provided on the circumference of the gear ring. A rotary motor is provided on the outer wall of the screen frame, and the rotating shaft of the rotary motor is coaxial and fixedly connected to the gear. The upper frame has a window above the gear ring, a sealing plate is detachably connected to the upper frame, and a mounting plate is detachably connected to the inner wall of the gear ring. The mounting plate is provided with scraping strips along the radial direction of the screen meshes, and the lower surface of the scraping strips is in contact with the upper surface of the screen meshes.

[0004] The existing vibrating screen may be clogged during use, resulting in deviation in the powder particle size. Therefore, an impact ball is set at the bottom or top of the screen. During screening, the impact ball bounces up and down to hit the screen, thereby unblocking the screen. Since the impact ball hits the screen irregularly, small balls may be concentrated in one area, and the screen cannot be fully unblocked. When less material enters, small particles tend to concentrate in the middle of the filter and pass through, resulting in low utilization of the effective area of ​​the screen. Fine particles need to travel a longer path to reach the screen surface, and the filter holes in the middle of the filter are more easily clogged than other parts. Summary of the Invention

[0005] The present invention provides a metal powder screening mechanism, which aims to solve the problems in the related art of using impact balls to clear the screen, that is, dead corners will appear when cleaning, and that effective clearing cannot be performed when a large amount of material enters.

[0006] The sieve mesh is arranged on the sieve frame, and a main shaft is installed at the sieve frame, and a plurality of fixing rings are installed on the main shaft to rotate coaxially. The middle part of the sieve mesh is connected with the fixing ring. A tensioning ring is installed on the inner side surface of each sieve frame for lifting. The edge of the sieve mesh passes around the tensioning ring and is connected to the sieve frame. A plurality of rotating rings are connected to the main shaft for rotation. A driving mechanism for controlling the rotation of the rotating ring is installed in the main shaft. The rotating ring is hinged with a plurality of slide rails along its circumferential direction. Impact balls are provided in the slide rails, and the inclination of the slide rails is the same as the taper of the sieve mesh. A funnel-shaped material guide ring coaxial with the sieve frame is provided below the slide rail. A lifting mechanism for controlling the lifting and lowering of the tensioning ring and the main shaft is installed in the sieve frame. When the material increases, the lifting mechanism causes the tensioning ring to rise and the main shaft to descend, thereby reducing the inclination of the sieve mesh, and slowing down the speed at which the material disperses to the edge.

[0007] The effect is: when there is less material, the slope of the screen is larger, avoiding the concentration of material in the middle of the screen, making the material disperse quickly, reducing the path of fine particles to reach the screen surface, and thus performing rapid screening; when the material increases, the lifting mechanism causes the tensioning ring to rise, the main shaft to descend, the slope of the screen to decrease, the speed at which the material slides down along the screen to slow down, and the speed at which the material disperses to slow down, thereby avoiding the material entering the standby area without being fully screened; during the screening process, the driving mechanism drives the rotating ring to rotate with the slide rail, so that the impact ball changes position under the screen, thereby fully and conveniently cleaning the screen.

[0008] Preferably, a plurality of partitions are evenly arranged on the slide rail along its length direction for separating the impact balls one by one, and the positions of the partitions on every two adjacent slide rails are staggered so that the impact balls can fully collide with all parts of the screen to avoid cleaning dead corners.

[0009] Preferably, the screen frame is provided with a connecting ring, and the connecting ring is coaxially rotatably connected to the tensioning ring, and the end of the slide rail away from the main shaft is slidably connected to a slide rod, and the slide rod is hinged to the connecting ring. When the main shaft rises, the end of the slide rail close to the main shaft rises, and the other end slides relative to the slide rod, and the slide rod rotates upward, so that the slide rail adapts to the slope of the screen.

[0010] Preferably, the inner diameter of the connecting ring is larger than the diameter of the guide ring.

[0011] Preferably, the fixing ring consists of an upper pressure ring and a lower pressure ring, the upper pressure ring is coaxially and detachably mounted on the lower pressure ring, a middle rotating ring for clamping the screen is rotatably connected to the main shaft, the center of the screen is clamped between the upper pressure ring and the lower pressure ring, the upper pressure ring and the lower pressure ring can be connected by bolts, and the lower pressure ring is fixedly mounted on the main shaft, so that the screen can be replaced by removing the upper pressure ring.

[0012] Preferably, the outer ring diameter of the guide ring is smaller than the inner ring diameter of the screen frame, so that the guide ring divides the screen into a screening area located inside the guide ring and a spare area located between the guide ring and the screen frame. When the material is small, the angle α between the truncated cone busbar l formed in the screening area and the horizontal plane is 4°-8°, and the angle between the truncated cone busbar i formed in the spare area and the horizontal plane is β, β>α. When the material is large, the angle between the truncated cone busbar l' formed in the screening area and the horizontal plane is α', α'>0, and the angle between the truncated cone busbar i' formed in the spare area and the horizontal plane is β', α>α', β'>β, and l+i=l' + After the equipment is started, the stacked screen frames vibrate, and the metal powder reaches the top screen frame. The frustum-shaped screen mesh vibrates, causing the powder to move in layers. Particles that meet the particle size requirements pass through the mesh openings and fall into the next screen frame. They are ultimately discharged through the discharge ports on the side walls of each layer of the screen frames. During this process, the screen mesh taper can be dynamically adjusted according to the material load. When the material is light, the frustum generatrix l of the screening zone maintains an angle α of 4°–8° with the horizontal plane. This allows the powder to diffuse rapidly toward the edges, reducing the path for fine particles to reach the screen surface and thus enabling rapid screening. As the material load increases, the tensioning ring rises, and the outer edge of the screening zone is retracted into the reserve zone, maintaining the screen taut. Finally, the screening zone angle decreases to α', slowing the powder's dispersion toward the edges and extending the screening time to ensure sufficient filtration. Throughout the adjustment process, the total length of the generatrix in the screening zone and the reserve zone remains constant (l + i = l' + i'), keeping the screen taut and preventing relaxation that affects screening accuracy.

[0013] Preferably, the lifting mechanism includes a linear drive source and a linkage assembly. The linear drive source is connected to the bottom of the main shaft to drive the main shaft to lift and lower. The linkage assembly is connected between the tensioning ring and the main shaft to drive the tensioning ring to move in the opposite direction of the movement direction of the driving main shaft.

[0014] The cam is provided with a plurality of guide rods along its circumferential direction, and the guide rods are slidably connected to the inner wall of the screen frame. The bottom end of the guide rod is provided with a connecting shaft 1, and a plurality of connecting shafts 2 are provided on the main shaft. The connecting shaft 1 and the connecting shaft 2 respectively cooperate with the slide grooves at both ends of the pressure rod. When the main shaft starts to descend, the connecting shaft 2 connected thereto also descends synchronously. The end of the pressure rod close to the guide rod gradually tilts up due to the action of the lever. As the pressure rod tilts up, the connecting shaft 1 is subjected to the corresponding lifting force, driving the guide rod to move upward together, eventually causing the position of the tensioning ring to rise. Conversely, when the main shaft rises, the rising action of the connecting shaft 2 will cause the end of the pressure rod close to the guide rod to gradually descend, and the descending of the pressure rod will be transmitted to the connecting shaft 1, causing it to drive the guide rod to descend together, eventually causing the position of the tensioning ring to descend, thereby adjusting the inclination of the screen according to the amount of material.

[0015] Preferably, the driving mechanism includes a driving shaft arranged in the main shaft, a gear is coaxially fixedly mounted on the driving shaft, and a gear ring meshing with the gear is arranged on the inner ring surface of the rotating ring. When the motor is started, the driving shaft starts to rotate, causing the gear to rotate synchronously, and the rotation of the gear drives the gear ring meshing with it. During the rotation process, the gear ring causes the rotating ring connected to it to rotate together, and the rotation of the rotating ring drives the slide rail and the connecting ring fixed to it to rotate synchronously, and finally the impact ball installed on the slide rail continuously changes its position under the screen. The change of the position of the impact ball effectively cleans all parts of the screen, ensuring that the screen will not affect its normal working efficiency due to blockage, thereby achieving an all-round and dead-angle cleaning effect on the screen.

[0016] Preferably, the main shaft is composed of a multi-section intermediate shaft, a string rod and a mounting shaft, the driving shaft is composed of a multi-section docking shaft, the intermediate shaft and the mounting shaft are both hollow, and multiple docking shafts are rotatably installed in the intermediate shaft and the mounting shaft respectively, and both ends of the docking shaft are provided with a connecting structure for docking with other docking shafts, and the intermediate shaft is provided with a through hole that runs through the upper and lower parts and is adapted to the string rod, and a limiting block is provided at the top of the string rod, and the bottom end of the string rod can be threadedly connected to the mounting shaft, so that all the intermediate shafts are passed through the mounting shaft through the string rod. During the installation process, the screen frames are first installed on the mounting plate in order from bottom to top, so that each screen frame is stable Fix them in the corresponding positions. After all the screen frames are installed, insert the string rod vertically downward from the through hole of the top intermediate shaft to ensure that the string rod can smoothly pass through the through hole of each intermediate shaft and connect all the intermediate shafts together in sequence. Then, rotate the string rod to make the external thread on the string rod engage with the internal thread in the intermediate shaft to ensure the overall stability of the main shaft. This completes the overall assembly of the main shaft. When disassembly maintenance or replacement of the filter is required, you only need to simply remove the string rod to easily disassemble any screen frame separately, which greatly simplifies the maintenance and replacement operation process and improves work efficiency.

[0017] By adopting the above technical solution, the beneficial effects of the present invention are:

[0018] 1. After the equipment is started, the vibration motor runs, driving the mounting plate and the screen frames stacked thereon to vibrate. At this time, the metal powder is fed into the top screen frame through the feed port and falls onto the frustum-shaped screen installed in the screen frame. Under the action of continuous vibration, the metal powder begins to move in layers, and particles that meet the specific particle size requirements can pass through the screen holes smoothly and fall into the screen frame on the lower layer. This process is carried out layer by layer, and finally the discharge ports on the side walls of each layer of the screen frame output powders of different particle sizes in a graded manner. In this screening process, the taper of the screen is dynamically adjusted according to the actual flow rate of the material. When the amount of material is small, the angle α between the frustum generatrix l of the screening area and the horizontal plane is 4° to 8°, which allows the powder to quickly move to the The edge of the screen frame diffuses to improve screening efficiency. However, when the amount of material increases, the system will start the electric push cylinder to push the main shaft down, which in turn drives the connecting shaft 2 to drop, causing the end of the pressure rod close to the guide rod to tilt, thereby driving the connecting shaft 1 and the guide rod to rise, and finally causing the tensioning ring to rise. During this process, the edge of the outer ring of the screening area will be retracted into the spare area to maintain the taut state of the screen. As the adjustment action is completed, the angle α' between the frustum busbar l' of the screening area and the horizontal plane is less than α, which slows down the flow of powder to the edge, thereby extending the screening time and ensuring that the powder can be fully filtered. During the entire adjustment process, the total length of the screen busbar remains constant (l+i=l' + i'), ensuring that the screen is always in a taut state, avoiding the impact of screening accuracy due to screen relaxation, and ensuring that the equipment can maintain screening performance under different material quantity conditions;

[0019] 2. During screening, the motor in the main shaft drives the gear to rotate, and the gear ring then drives the rotating ring to rotate. The rotating ring then drives the slide rail and the connecting ring to rotate, causing the slide rail to revolve around the main shaft. The impact balls separated by the partitions on the slide rail move with the track. The adjacent slide rail partitions are staggered to ensure that the impact points fully cover the screen without dead angles. The sliding rod at the end of the slide rail is hinged to the connecting ring, and the connecting ring rises and falls with the tensioning ring to ensure that the impact ball and the bottom of the screen always maintain an effective impact distance of 5-10mm. The impact ball continuously collides with the screen under the action of vibration, shaking off stuck particles and unblocking the screen holes. The powder under the screen is concentrated and diverted to the middle of the lower screen through the funnel-shaped guide ring, and this screening process is repeated. Through the mechanical linkage of the screen taper adjustment and the rotary screen cleaning, the equipment can achieve good screening effects when processing different material quantities;

[0020] 3. The main shaft and drive shaft are segmented and assembled. A string rod is used to string vertically downward from the through hole of the uppermost intermediate shaft so that all the intermediate shafts are threaded together. Then the string rod is rotated so that the external thread on it engages with the internal thread hole on the mounting shaft to complete the assembly of the main shaft. This arrangement facilitates disassembly and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a front view of the present invention.

[0022] Figure 2 It is a cross-sectional view of the present invention.

[0023] Figure 3 It is a structural schematic diagram of the tensioning ring in the present invention.

[0024] Figure 4 It is a schematic diagram of the explosion structure of the screen frame in the present invention.

[0025] Figure 5 for Figure 4 Schematic diagram of the enlarged structure at point A in the middle.

[0026] Figure 6 This is a schematic diagram of the state when the slope of the screening area in the present invention is relatively small.

[0027] Figure 7 This is a schematic diagram of the state when the slope of the screening area in the present invention is large.

[0028] Figure 8 It is a cross-sectional view of the main shaft in the present invention.

[0029] Reference numerals:

[0030] 1. Vibration base; 11. Counterweight platform; 12. Spring; 13. Vibration motor; 14. Mounting plate; 2. Top cover; 3. Screen frame; 31. Screen; 32. Dredging device; 321. Rotating ring; 322. Connecting ring; 323. Driving mechanism; 3231. Motor; 3232. Driving shaft; 3233. Gear; 3234. Gear ring; 324. Slide rail; 3241. Slide rod; 325. Impact ball; 33. Lifting mechanism; 331. Linear drive source; 332. Pressure rod; 333. Guide rod; 334. Articulated seat; 34. Fixing ring; 341. Upper pressure ring; 342. Lower pressure ring; 35. Tensioning ring; 36. Guide ring; 4. Main shaft; 41. Intermediate shaft; 42. Mounting shaft; 43. End cover; 44. String rod. DETAILED DESCRIPTION

[0031] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0032] like Figure 1 and Figure 2 As shown, a metal powder screening mechanism includes a vibration base 1, a top cover 2, and multiple screen frames 3. The multiple screen frames 3 are stacked and detachably connected together (for example, connected together by bolts or snaps). The vibration base 1 includes a counterweight platform 11, multiple springs 12, a vibration motor 13 and a mounting plate 14. The mounting plate 14 is located above the counterweight platform 11, and the two are connected by a spring 12. The vibration motor 13 is installed in a mounting tube, and the output end of the vibration motor 13 is fixedly connected to an eccentric block. The mounting tube is coaxially installed at the bottom of the mounting plate 14. The bottom screen frame 3 is fixedly installed on the top surface of the mounting plate 14, and the top cover 2 is installed on the top screen frame 3. The vibration of the vibration motor 13 causes the mounting plate 14 and the screen frame 3 to vibrate, thereby screening and grading the metal powder in the screen frame 3.

[0033] like Figure 1-Figure 5 As shown, a screen 31, an adjusting device and a dredging device 32 are installed in the screen frame 3. A feed port is provided on the top of the top cover 2, and discharge ports are provided on the sides of the screen frame 3 and the top cover 2. All discharge ports are staggered with each other. The screen 31 is in the shape of a cone. The adjusting device is used to adjust the inclination of the screen 31 according to the amount of material. When there is a lot of material, the inclination of the screen 31 is reduced to avoid the material reaching the edge of the screen frame 3 too quickly and resulting in insufficient screening. The dredging device 32 is installed at the bottom of the screen 31 for dredging the screen 31. A guide ring 36 is fixedly installed in the screen frame 3, and the guide ring 36 is located below the screen 31, thereby guiding the screened material into the middle of the next-level screen 31.

[0034] The adjusting device includes a main shaft 4, a lifting mechanism 33, a fixing ring 34 and a tensioning ring 35. The main shaft 4 is coaxially lifted and installed on the mounting plate 14, and the main shaft 4 enters the screen frame 3, so that the main shaft 4 can be lifted and lowered in the screen frame 3. The fixing ring 34 is fixedly installed on the main shaft 4, and the fixing ring 34 is connected to the center of the screen 31. The tensioning ring 35 is against the bottom of the screen 31 near the edge. The lifting mechanism 33 is used to control the simultaneous lifting of the main shaft 4 and the tensioning ring 35, and the two move in opposite directions. The tensioning ring 35 divides the screen 31 into two areas. The area inside the guide ring 36 is the screening area, and the area between the guide ring 36 and the screen frame 3 is the spare area.

[0035] like Figure 1-Figure 7 As shown, during screening, when the amount of material entering is small, the angle between the truncated cone busbar l formed in the screening area and the horizontal plane is α, 4°<α<8°, the angle between the truncated cone busbar i formed in the standby area and the horizontal plane is β, and β>α. When the amount of material entering is large, the lifting mechanism 33 causes the main shaft 4 to descend, thereby causing the fixed ring 34 to descend with the middle part of the screen 31, and at the same time the tensioning ring 35 rises, thereby causing the position of the boundary circle between the screening area and the standby area to rise. At this time, the angle between the truncated cone busbar l' formed in the screening area and the horizontal plane is α', 0°<α'<4°, and the angle between the truncated cone busbar i' formed in the standby area and the horizontal plane is β'. At this time, due to the reduction in the slope of the screening area, the material disperses slowly, thereby preventing the material from entering the standby area without being fully screened, and then being discharged from the discharge port on the screen frame 3. In the above process, α>α', β'>β, and at the same time l+i=l'+i', to keep the screen 31 taut.

[0036] The fixing ring 34 is composed of an upper pressure ring 341 and a lower pressure ring 342. The center of the screen 31 is clamped between the upper pressure ring 341 and the lower pressure ring 342. The upper pressure ring 341 and the lower pressure ring 342 are connected by bolts. The lower pressure ring 342 is fixed on the main shaft 4. The outer edge of the fixed screen 31 is fixed on the top surface of the screen frame 3. The screen 31 can be replaced by removing the mounting ring and the upper pressure ring 341.

[0037] The lifting mechanism 33 includes a linear drive source 331 and multiple linkage components. The linear drive source 331 is preferably an electric push cylinder. The top of the piston rod of the electric push cylinder is fixedly installed on the bottom of the mounting plate 14. The cylinder body of the electric push cylinder is fixedly connected to the main shaft 4, so that the main shaft 4 is controlled to rise and fall by the electric push cylinder. The linkage component is connected between the tensioning ring 35 and the main shaft 4. When the main shaft 4 rises, the tensioning ring 35 is driven to descend through the linkage component, thereby releasing the inner ring edge part of the spare area. The main shaft 4 rises to keep the screen 31 taut. When the main shaft 4 falls, the tensioning ring 35 is driven to rise through the linkage component, thereby bringing the outer ring edge part of the screening area into the spare area to keep the screen 31 taut.

[0038] The linkage assembly includes multiple pressure rods 332, multiple guide rods 333 and hinge seats 334. Multiple guide rods 333 are fixedly installed in a circular array at the bottom of the tensioning ring 35. The guide rods 333 are slidably connected to the inner wall of the screen frame 3 up and down, and a connecting shaft 1 is provided on both sides of the bottom end of the guide rod 333. The hinge seat 334 is fixedly installed on the main shaft 4. Multiple connecting shafts 2 are provided on the hinge seat 334. The two ends of the pressure rod 332 are respectively provided with sliding grooves that are compatible with the connecting shaft 1 and the connecting shaft 2, so that the two ends of the pressure rod 332 slide and rotate with the connecting shaft 1 and the connecting shaft 2 respectively. The pressure rod 332 is hinged to the guide ring 36. When the main shaft 4 descends, the connecting shaft 2 descends, so that the end of the pressure rod 332 close to the guide rod 333 is tilted, so that the connecting shaft 1 rises with the guide rod 333, thereby causing the tensioning ring 35 to rise. Conversely, the main shaft 4 rises and the tensioning ring 35 descends.

[0039] The dredging device 32 includes a rotating ring 321, a connecting ring 322, a driving mechanism 323, a plurality of slide rails 324 and a plurality of impact balls 325. The number of the connecting ring 322 and the rotating ring 321 is the same as the number of the screen frame 3. The rotating ring 321 is rotatably mounted on the main shaft 4, and a retaining ring fixedly connected to the main shaft 4 is provided above it. The radius of the retaining ring bottom is greater than the radius of the pressure ring top to prevent metal particles from affecting the rotation of the rotating ring 321. The rotating ring 321 is arranged at equal intervals along the length direction of the main shaft 4. The driving mechanism 323 is arranged Installed in the main shaft 4, used to control the synchronous rotation of all rotating rings 321, each rotating ring 321 is hinged with multiple slide rails 324, and multiple slide rails 324 are arranged at equal intervals along the circumference of the rotating ring 321, each slide rail 324 is provided with a group of impact balls 325, and the distance between the top of the impact ball 325 and the screen 31 is 5mm-10mm, so as to ensure effective impact and cleaning of the screen 31, multiple partitions are arranged at equal intervals on the slide rail 324 to separate the impact balls 325 one by one, and every two adjacent slide rails are arranged at equal intervals. The positions of the partitions on 324 are staggered with each other, so that the impact ball 325 can fully impact with all parts of the screen 31 to avoid cleaning dead corners. The end of the slide rail 324 away from the rotating ring 321 is slidably connected to the slide rod 3241, and the slide rod 3241 is hinged to the connecting ring 322. The inner side of the guide rod 333 is provided with a mounting groove opening in the direction of the main shaft 4, and the mounting groove is adapted to the connecting ring 322. In order to reduce the friction between the two, a roller can be installed in the mounting groove, so that there is rolling friction between the roller and the connecting ring 322. , reducing frictional resistance. This setting can keep the distance between the connecting ring 322 and the tensioning ring 35 unchanged, and enable the connecting rod to rotate with the slide rail 324. When the main shaft 4 rises, the rotating ring 321 rises accordingly, the tensioning ring 35 falls, and the connecting ring 322 falls accordingly, so that the distance between the screen 31 and the slide rail 324 remains the same. When screening, the driving makes the rotating ring 321 rotate slowly, so that the impact ball 325 rotates accordingly, thereby impacting various parts of the screen 31 to clean the screen and dredge the sieve holes.

[0040] The driving mechanism 323 includes a motor 3231, a driving shaft 3232, multiple gears 3233 and multiple gear rings 3234. The motor 3231 is fixedly mounted on the bottom end of the main shaft 4, and the output end of the motor 3231 is fixedly connected to the driving shaft 3232. The driving shaft 3232 is not colinear with the axis of the main shaft 4. Multiple gears 3233 are fixedly mounted on the driving shaft 3232 at equal intervals. The gear ring 3234 is fixedly connected to the inner ring surface of the rotating ring 321, and the gear 3233 is meshed with the gear ring 3234. When the motor 3231 is started, the driving shaft 3232 rotates to rotate the gear 3233, thereby causing the gear ring 3234 to rotate with the rotating ring 321, and the rotating ring 321 rotates with the slide rail 324 and the connecting ring 322, so that the impact ball 325 changes its position under the screen 31, thereby clearing the screen 31 in all directions.

[0041] Working principle: After the equipment is started, the vibration motor 13 drives the mounting plate 14 and the stacked screen frames 3 to vibrate, and the metal powder enters the uppermost screen frame 3 from the feed port. The frustum-shaped screen 31 causes the powder to move in layers under vibration, and particles that meet the particle size pass through the screen holes and fall into the lower layer. Finally, they are graded and output from the discharge ports on the side walls of each layer of the screen frame 3. In this process, the taper of the screen 31 is dynamically adjusted according to the amount of material. When the material is small, the frustum busbar l of the screening area maintains an angle α of 4°–8° with the horizontal plane, and the powder quickly moves to the edge. Diffusion. If the material increases, the electric push cylinder pushes the main shaft 4 down, and the connecting shaft 2 drops down, so that the end of the pressure rod 332 close to the guide rod 333 rises, so that the connecting shaft 1 and the guide rod 333 rise, and the tensioning ring 35 rises. At the same time, the edge of the outer ring of the screening area is retracted into the spare area to keep the screen 31 tight. Finally, the angle of the screening area is reduced to α', and the flow speed of the powder to the edge is slowed down, which prolongs the screening time to ensure sufficient filtration. During the entire adjustment, the total length of the busbar of the screen 31 is constant (l+i=l'+i'), and it is always kept tight to avoid relaxation affecting the screening accuracy.

[0042] During the screening process, the motor 3231 in the main shaft 4 drives the gear 3233 to rotate, thereby causing the gear ring 3234 to rotate with the rotating ring 321, and the rotating ring 321 rotates with the slide rail 324 and the connecting ring 322, so that the slide rail 324 revolves around the main shaft 4, and the impact balls 325 separated by the partitions on the slide rail 324 move with the track, and the partitions of adjacent slide rails 324 are staggered to ensure that the impact point fully covers the screen 31 without dead angles, and the sliding rod 3241 at the end of the slide rail 324 and the connecting ring 32 2 is hinged, and the connecting ring 322 rises and falls with the tensioning ring 35, so that the impact ball 325 and the bottom of the screen 31 always maintain an effective impact distance of 5-10 mm. The impact ball 325 continuously collides with the screen 31 under the action of vibration, shakes off the blocked particles, unclogs the screen holes, and the powder under the screen is concentratedly guided to the middle of the lower screen 31 through the funnel-shaped guide ring 36, and the above screening process is repeated. Through the mechanical linkage of the taper adjustment of the screen 31 and the rotary screen cleaning, the equipment can achieve good screening effect when dealing with different material quantities.

[0043] like Figure 4 and Figure 8As shown, in order to facilitate disassembly, the main shaft 4 and the drive shaft 3232 are set as a segmented assembly. The main shaft 4 includes an end cover 43, a multi-section intermediate shaft 41, a string rod 44 and a mounting shaft 42. The drive shaft 3232 is composed of a multi-section docking shaft. The mounting shaft 42 is slidably mounted in the middle of the mounting plate 14, and the intermediate shaft 41 and the mounting shaft 42 are both hollow. Multiple docking shafts are rotatably mounted in the intermediate shaft 41 and the mounting shaft 42 respectively. One end of the docking shaft is provided with an inner hexagonal driving hole, and the other end is provided with a hexagonal driving hole. The hexagonal drive hole is matched with the hexagonal drive head, and the lowermost docking shaft is fixedly connected to the output end of the motor 3231. The intermediate shaft 41 is provided with a through hole that passes through from top to bottom, and the through hole is matched with the string rod 44. The top of the string rod 44 is provided with a limit block, and the bottom end of the string rod 44 is provided with an external thread. The top surface of the mounting shaft 42 is provided with an internal thread hole that is matched with the external thread, so that all the intermediate shafts 41 are threaded together through the string rod 44, and then the intermediate shafts 41 are prevented from disengaging by the limit block and the mounting shaft 42.

[0044] During installation, the screen frame 3 is installed on the mounting plate 14 from bottom to top. After the screen frame 3 is installed, the string rod 44 is threaded downward from the through hole of the uppermost intermediate shaft 41, and all the intermediate shafts 41 are passed together. Then the string rod 44 is rotated to make the external thread engage with the internal thread, and finally the end cover 43 is installed on the top of the uppermost intermediate shaft 41 to complete the assembly of the main shaft 4. In this way, when disassembling, you only need to remove the string rod 44 to remove any screen frame 3 separately for maintenance or replacement of the filter screen.

[0045] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A metal powder screening mechanism, comprising a vibrating base and a top cover, wherein a plurality of screen frames are installed between the vibrating base and the top cover, and a screen mesh is arranged in the screen frame, characterized in that: A main shaft is installed at the axis of the screen frame, and multiple fixed rings are coaxially installed on the main shaft. The middle part of the screen is connected to the fixed ring. A tensioning ring is installed on the inner side of each screen frame for lifting and lowering. The edge of the screen passes around the tensioning ring and is connected to the screen frame. Multiple rotating rings are rotatably connected to the main shaft, and a driving mechanism for controlling the rotation of the rotating ring is installed in the main shaft. Multiple slide rails are hinged on the rotating ring along its circumferential direction. Impact balls are provided in the slide rails. The inclination of the slide rails is the same as that of the screen. A funnel-shaped material guide ring coaxial with the screen frame is provided below the slide rail. A lifting mechanism for controlling the lifting and lowering of the tensioning ring and the main shaft is installed in the screen frame. When the material increases, the lifting mechanism causes the tensioning ring to rise and the main shaft to descend, thereby reducing the inclination of the screen and slowing down the speed at which the material disperses to the edge. The outer ring diameter of the guide ring is smaller than the inner ring diameter of the screen frame, so that the guide ring divides the screen into a screening area located inside the guide ring and a spare area located between the guide ring and the screen frame. When the material is less, the angle α between the frustum busbar l formed in the screening area and the horizontal plane is 4°-8°, and the angle between the frustum busbar i formed in the spare area and the horizontal plane is β, β>α. When the material is more, the angle between the frustum busbar l' formed in the screening area and the horizontal plane is α', α'>0, and the angle between the frustum busbar i' formed in the spare area and the horizontal plane is β', α>α', β'>β, and l+i=l' + i'.

2. The metal powder screening mechanism according to claim 1, characterized in that: A plurality of partitions are evenly arranged on the slide rail along its length direction for separating the impact balls one by one, and the positions of the partitions on every two adjacent slide rails are staggered with each other.

3. The metal powder screening mechanism according to claim 1, characterized in that: The screen frame is provided with a connecting ring, and the connecting ring is coaxially rotatably connected with the tensioning ring. One end of the slide rail away from the main shaft is slidably connected with a slide rod, and the slide rod is hinged to the connecting ring.

4. The metal powder screening mechanism according to claim 3, characterized in that: The inner diameter of the connecting ring is greater than the diameter of the guide ring.

5. The metal powder screening mechanism according to claim 1, characterized in that: The fixing ring is composed of an upper pressure ring and a lower pressure ring. The upper pressure ring is coaxially detachably mounted on the lower pressure ring. A middle rotating ring for clamping the screen is rotatably connected to the main shaft.

6. The metal powder screening mechanism according to claim 1, characterized in that: The lifting mechanism includes a linear drive source and a linkage assembly. The linear drive source is connected to the bottom of the main shaft to drive the main shaft to lift and lower. The linkage assembly is connected between the tensioning ring and the main shaft to drive the tensioning ring to move in the opposite direction of the movement direction of the driving main shaft.

7. The metal powder screening mechanism according to claim 6, characterized in that: The linkage assembly includes multiple pressure rods hinged on the guide ring, and slide grooves are provided at both ends of the pressure rods. Multiple guide rods are provided along the circumferential direction of the bottom of the tensioning ring. The guide rods are connected to the inner wall of the screen frame for up and down sliding. A connecting shaft 1 is installed at the bottom end of the guide rod, and multiple connecting shafts 2 are provided on the main shaft. The connecting shaft 1 and the connecting shaft 2 are respectively matched with the slide grooves at both ends of the pressure rod.

8. The metal powder screening mechanism according to claim 1, characterized in that: The driving mechanism includes a driving shaft arranged in the main shaft, a gear is coaxially fixedly installed on the driving shaft, and a gear ring meshing with the gear is arranged on the inner ring surface of the rotating ring.

9. The metal powder screening mechanism according to claim 8, characterized in that: The main shaft is composed of a multi-section intermediate shaft, a string rod and an installation shaft, and the drive shaft is composed of a multi-section docking shaft. The intermediate shaft and the installation shaft are both hollow, and multiple docking shafts are rotatably installed in the intermediate shaft and the installation shaft respectively. Both ends of the docking shaft are provided with connection structures for docking with other docking shafts. The intermediate shaft is provided with a through hole that passes through the upper and lower parts and is compatible with the string rod. A limit block is provided at the top of the string rod, and the bottom end of the string rod can be threadedly connected to the installation shaft, so that all the intermediate shafts are passed through the installation shaft through the string rod.

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