A sintered neodymium-iron-boron magnet surface defect detection device of magnetic shielding protection

Abstract

The application discloses a kind of sintered neodymium-iron-boron magnet surface defect detection devices of magnetic shielding protection, it is related to neodymium-iron-boron magnet detection relevant field, including detection box and fixed in its workbench, workbench top is equipped with the CCD camera assembly of acquisition circular sintered neodymium-iron-boron magnet image, the camera outside of the CCD camera assembly is nested with magnetic shielding shield cover;The upper air passage is communicated with limiting mechanism and rolling mechanism respectively through gas pipe, limiting mechanism execution end is two groups of symmetrical arc blocks, and the rolling mechanism execution end is the roller that rotates and is located in the inside of limiting block.This sintered neodymium-iron-boron magnet surface defect detection device of magnetic shielding protection, by with hydraulic push rod as core driving source, simultaneously drive CCD camera lifting and moving piston rod sliding, by means of the double air passage layout inside moving piston rod;Electric push rod can adjust the distance between two groups of limiting blocks, adapt to different diameter specifications circular magnet, wide application range.

Description

Technical Field

[0001] This invention relates to the technical field of NdFeB magnet testing, specifically to a magnetically shielded sintered NdFeB magnet surface defect detection device. Background Technology

[0002] Sintered NdFeB magnets, with their high magnetic energy product, are widely used in new energy vehicles, wind power, and precision motors. However, after forming, sintering, and grinding, they are prone to surface defects such as cracks, missing corners, pitting, and scratches. These defects can damage the protective coating, disrupt the magnetic circuit, and significantly reduce the overall reliability of the device. Currently, the industry relies on manual visual inspection, which results in dull magnet surfaces, low contrast for minor defects, and worker fatigue from prolonged operation, leading to high rates of missed and false detections. The inspection efficiency is difficult to match mass production capacity. Existing machine vision equipment mostly uses fixed-station two-dimensional imaging, which cannot completely cover the entire surface of curved or irregularly shaped magnets. Surface sintering textures are easily confused with micro-defects, resulting in a large number of misjudgments. Contact inspection tools can also scratch finished magnets, causing secondary scrapping.

[0003] To address the aforementioned issues, a magnet appearance defect detection device disclosed in existing technology (Chinese patent application number CN201721375184.5, application date October 24, 2017) can be referenced. This device uses a cylinder piston rod to extend, lifting one end of a fixture plate and tilting it. This tilts the magnet on the fixture plate at a certain angle. A lifting drive mechanism then drives a combined light source downwards to approach the fixture plate, where a CCD camera takes a second picture of the magnet. The detection results are displayed on a computer. Finally, the lifting drive mechanism drives the combined light source upwards, and the cylinder piston rod retracts. This second image primarily detects minor scratches on the magnet surface. The cylinder, lifting drive mechanism, and CCD camera can all be controlled by a PLC controller. By adopting the above solution, manpower can be reduced, efficiency can be improved, the accuracy of magnet appearance inspection can be increased, material loss can be reduced, thereby reducing production costs. Furthermore, a magnet size and appearance defect detection device disclosed in existing technology (Chinese patent application number CN202223080864.8, application date 2022.11.21) can be referenced. This device uses a microscope and a movement control device to achieve precise positioning of the microscope head; the microscope, in conjunction with a display screen, provides a direct display of the alignment between the product and the probe, as well as the product's appearance. The device enables faster placement, a more accurate testing environment, and a more precise method for measuring the product's appearance and size.

[0004] While existing appearance inspection devices can complete basic quality inspection of NdFeB magnets, they still have significant shortcomings. For the inspection of circular and annular sintered NdFeB magnets, the entire surface of the magnet needs to be fully covered to ensure the completeness of defect identification. The existing equipment has a complex imaging inspection process for the outer peripheral sidewalls of circular magnets, and the station switching and workpiece flipping operations are cumbersome, making it difficult to quickly and completely acquire sidewall images, which easily leads to the problem of missing micro-defects on the sidewalls.

[0005] Therefore, we propose a magnetically shielded surface defect detection device for sintered NdFeB magnets to address the problems mentioned above. Summary of the Invention

[0006] The purpose of this invention is to provide a magnetically shielded sintered NdFeB magnet surface defect detection device to address the issues raised in the background art regarding the current market conditions for detecting circular and annular sintered NdFeB magnets. To ensure the completeness of defect identification, the entire surface of the magnet needs to be fully covered. Existing equipment has a complex imaging detection process for the outer peripheral sidewalls of circular magnets, with cumbersome station switching and workpiece flipping operations, making it difficult to quickly and completely acquire sidewall images and easily leading to missed detections of micro-defects on the sidewalls.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a magnetically shielded surface defect detection device for sintered NdFeB magnets, comprising a detection box and a worktable fixed therein, a CCD camera assembly for acquiring images of circular sintered NdFeB magnets is provided above the worktable, and a magnetic shielding cover is nested outside the camera of the CCD camera assembly; a hydraulic push rod is fixedly mounted on the rear side of the worktable, and its output end is fixedly connected to the bottom of the CCD camera assembly, and two sets of movable piston rods are symmetrically connected to the outside of the output end via support rods; the outer wall of the movable piston rod slides against the inner wall of the fixed cylinder, and the outer sides of both sets of fixed cylinders are fixedly connected to the output end of the electric push rod, and the front end of the fixed cylinder is slidably sleeved on a horizontal surface. The guide rod is fixed to the outside of the upper end of the workbench; the end of the movable piston rod that extends into the fixed cylinder is provided with an inner tube, and an annular upper air passage is formed between the outer wall of the inner tube and the inner wall of the movable piston rod, and the inner cavity of the inner tube is a lower air passage; the side wall of the fixed cylinder is respectively fitted with a first air inlet that connects to the upper air passage and a second air inlet that connects to the lower air passage; the front end of the lower air passage is connected to a flipping mechanism, the output end of the flipping mechanism is fixedly connected to a rotating block, the outer end of the rotating block is fixedly connected to a limiting block, and the two sets of limiting blocks are used to clamp the magnet to be tested; the upper air passage is connected to the limiting mechanism and the rolling mechanism through the air supply pipe, the execution end of the limiting mechanism is two sets of symmetrical arc blocks, and the execution end of the rolling mechanism is a roller that is rotatably located inside the limiting block.

[0008] Preferably, the inner tube is fixedly disposed in the internal cavity of the movable piston rod, and the first air inlet and the second air inlet are both nested and fixed to the side wall of the fixed cylinder, and the two sets of fixed cylinders are symmetrically distributed about the vertical center line of the worktable.

[0009] Preferably, the support rod includes a connecting sleeve that is fixedly connected to the outside of the CCD camera assembly. The outer end of the connecting sleeve is rotatably connected to a telescopic rod via a rotating shaft. The outer end of the telescopic rod is rotatably connected to a fixing ring. The fixing ring is rotatably sleeved on the outside of the rod body where the movable piston rod is located above the fixed cylinder.

[0010] Preferably, the lower air passage includes a conical hole at the bottom of the movable piston rod, a conical plug is fitted to the inner wall of the conical hole, and the upper end of the conical plug is connected to the lower inner wall of the inner tube by a return spring; a piston rod is slidably fitted to the inner side of the upper end of the inner tube, the upper end of the piston rod is fixed to the top inner wall of the inner tube by a connecting spring, the top end of the piston rod extends out of the outer side of the inner tube and is rotatably connected to a rotating rod, the upper end of the rotating rod is rotatably connected to the edge of the disc, and the center of the disc is fixedly connected to the rotating block.

[0011] Preferably, the rotation angle range of the disc is 0° to 180°, the rotating block is rotatably disposed on the upper inner side of the inner tube, and the piston rod is located below the rotating rod.

[0012] Preferably, the upper air passage includes a one-way air inlet on the upper side wall of the movable piston rod. The one-way air inlet is connected to the annular gap between the movable piston rod and the inner tube. The annular gap is connected to the air inlet end of the air supply pipe. The air outlet end of the air supply pipe is divided into two paths, which are respectively connected to the limiting mechanism and the rolling mechanism.

[0013] Preferably, the limiting mechanism includes a first telescopic member connected to the outlet end of the gas pipeline. An arc-shaped block is fixedly connected to the bottom of the first telescopic member. A roller is rotatably arranged at the bottom of the arc-shaped block. The bottom of the roller is attached to the end face edge of the circular sintered NdFeB magnet. The two sets of arc-shaped blocks are symmetrically distributed about the transverse center line of the limiting block.

[0014] Preferably, the first telescopic member includes a vertical cylinder fixed inside the limiting block, an extension rod is slidably disposed on the inner side of the vertical cylinder, and the top of the extension rod is connected to the inner wall of the top of the vertical cylinder by a cooperating spring.

[0015] Preferably, the rolling mechanism includes a roller rotatably disposed inside the limiting block, the roller having a spiral groove inside, a spiral block being spirally connected to the inner side of the spiral groove, the top of the spiral block being fixedly connected to the output end of the second telescopic member, and the air inlet end of the second telescopic member being connected to the other air outlet end of the air supply pipe.

[0016] Preferably, the second telescopic member has the same internal structure as the first telescopic member, and the stiffness coefficient of the spring inside the second telescopic member is greater than that of the spring inside the first telescopic member.

[0017] Compared with existing technologies, the beneficial effects of this invention are as follows: This magnetically shielded sintered NdFeB magnet surface defect detection device, using a hydraulic push rod as the core driving source, synchronously drives the CCD camera to rise and fall and the moving piston rod to slide. Utilizing the dual-airway layout inside the moving piston rod, it can sequentially trigger multiple actions including limit clamping, circumferential rotation, and 180° flipping, enabling complete image acquisition of the magnet's upper surface, all circumferential sidewalls, and lower surface. This effectively solves the problems of cumbersome sidewall detection processes and easy omission of bottom surface defects in traditional equipment. The magnetically shielded cover nested outside the CCD camera can block the interference of the strong permanent magnet stray magnetic field of NdFeB on the photosensitive chip and signal circuit, eliminating imaging stripes and light spot artifacts, and avoiding false defect misjudgments. The electric push rod can adjust the distance between the two sets of limit blocks, adapting to circular magnets of different diameters, thus having a wide range of applications. Specific details are as follows: 1. Through the coordinated operation of the pneumatic rolling mechanism and the flipping mechanism, the entire surface of a circular sintered NdFeB magnet can be inspected without any blind spots. The rolling mechanism uses a helical transmission structure to drive the rollers to rotate, which can make the magnet rotate uniformly in the circumferential direction while it is being held. With the help of the CCD camera fixed above, the surface images of the entire circumference of the magnet can be continuously acquired, avoiding missed inspections in blind spots on the side walls. The flipping mechanism can drive the limiting block to make the magnet complete a precise 180° flip, completing the full coverage inspection of the upper and lower end faces and side walls in one go, solving the problems of manual flipping and lengthy inspection processes required by traditional equipment. At the same time, the magnetic shielding cover can isolate the strong magnetic field interference of the NdFeB magnet. The bottom of the arc-shaped block of the limiting mechanism is equipped with rollers, which can clamp and limit the magnet without hindering its rotation, and avoid contact and scratching the magnet surface, achieving non-destructive high-precision quality inspection. 2. The difference in the stiffness coefficient of the internal springs of the two sets of telescopic components can automatically realize the action sequence of limiting before rotation, ensuring stable clamping during magnet rotation detection and avoiding image blurring caused by offset and shaking; at the same time, the electric push rod can drive the two sets of fixed cylinders to move along the guide rod, quickly adjust the clamping distance, adapt to the detection needs of circular and annular NdFeB magnets of different diameters, and greatly improve the versatility and mass production adaptability of the detection equipment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the main structure of the present invention; Figure 2 This is a schematic diagram of the main structure of the workbench of the present invention; Figure 3 This is a schematic diagram of the rear view structure of the worktable of the present invention; Figure 4 This is a schematic diagram of the main structure of the CCD camera assembly of the present invention; Figure 5 This is a schematic diagram of the main cross-sectional structure of the fixed cylinder of the present invention; Figure 6 This is a partial front view cross-sectional structural diagram of the movable piston rod of the present invention; Figure 7 For the present invention Figure 2 Enlarged structural diagram at point A in the middle; Figure 8 This is a side view of the limiting block structure of the present invention; Figure 9 This is a schematic diagram of the main cross-sectional structure of the first telescopic component of the present invention; Figure 10 This is a schematic diagram of the main cross-sectional structure of the roller of the present invention.

[0019] In the diagram: 1. Detection box; 2. Workbench; 3. Hydraulic push rod; 4. Support rod; 41. Connecting sleeve; 42. Telescopic rod; 43. Fixing ring; 5. CCD camera assembly; 51. Shielding cover; 6. Moving piston rod; 7. Fixed cylinder; 71. First air inlet; 72. Second air inlet; 8. Electric push rod; 9. Guide rod; 10. Conical plug; 11. Return spring; 12. Inner tube; 13. Piston vertical rod; 131. Connecting spring; 14. Rotating rod; 15. Disc; 16. Rotating block; 17. Limiting block; 18. Air supply pipe; 19. First telescopic component; 191. Vertical cylinder; 192. Extension rod; 193. Matching spring; 20. Arc-shaped block; 21. Roller; 211. Spiral groove; 22. Second telescopic component; 23. Spiral block. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figures 1-10 The present invention provides the following technical solution: Reference Appendix Figure 1 -Appendix Figure 3A magnetically shielded surface defect detection device for sintered NdFeB magnets includes a detection box 1 and a worktable 2 fixed inside it. A CCD camera assembly 5 for acquiring images of circular sintered NdFeB magnets is mounted above the worktable 2. A magnetic shielding cover 51 is nested outside the camera of the CCD camera assembly 5. A hydraulic push rod 3 is fixedly mounted on the rear side of the worktable 2, with its output end fixed to the bottom of the CCD camera assembly 5. Two sets of movable piston rods 6 are symmetrically connected to the output end via a support rod 4. The outer wall of the movable piston rod 6 slides against the inner wall of a fixed cylinder 7. The outer sides of both sets of fixed cylinders 7 are fixedly connected to the output end of an electric push rod 8. The front end of the fixed cylinder 7 is slidably sleeved on a guide rod 9 horizontally fixed to the upper end of the worktable 2. On the side; the end of the movable piston rod 6 that extends into the fixed cylinder 7 is provided with an inner tube 12, and an annular upper air passage is formed between the outer wall of the inner tube 12 and the inner wall of the movable piston rod 6, and the inner cavity of the inner tube 12 is a lower air passage; the side wall of the fixed cylinder 7 is respectively fitted with a first air inlet 71 that connects to the upper air passage and a second air inlet 72 that connects to the lower air passage; the front end of the lower air passage is connected to a flipping mechanism, the output end of the flipping mechanism is fixedly connected to a rotating block 16, the outer end of the rotating block 16 is fixedly connected to a limiting block 17, and the two sets of limiting blocks 17 are used to clamp the magnet to be tested; the upper air passage is connected to the limiting mechanism and the rolling mechanism through the air supply pipe 18, the execution end of the limiting mechanism is two sets of symmetrical arc blocks 20, and the execution end of the rolling mechanism is a roller 21 that is rotatably located inside the limiting block 17.

[0022] The entire assembly is installed inside the testing box 1. The workbench 2 is horizontally fixed as the mounting base. The CCD camera assembly 5 is suspended directly above the workbench 2. The magnetic shielding cover 51 nested on the outside of the camera can block the strong stray magnetic field of the neodymium iron boron magnet, avoiding magnetic field interference with the photosensitive chip and causing imaging artifacts. The hydraulic push rod 3 on the rear side of the workbench 2 is the core lifting drive source. The output end directly supports the CCD camera assembly 5. At the same time, the lifting power is synchronously transmitted to the moving piston rods 6 on both sides through the support rod 4. The electric push rod 8 can push the two sets of fixed cylinders 7 to slide horizontally towards or away from each other along the guide rod 9 to meet the clamping requirements of circular magnets of different diameters. During operation, the magnet to be tested is placed between the two sets of limit blocks 17. The electric push rod 8 drives the limit blocks 17 to complete the initial clamping. While the hydraulic push rod 3 drives the CCD camera assembly 5 to lift and focus, it drives the moving piston rod 6 to slide along the fixed cylinder 7. The dual air passage structure inside the moving piston rod 6 triggers the limiting, circumferential rotation and flipping actions in sequence. The full surface image of the magnet can be completed in a single station.

[0023] Reference Appendix Figure 5 and attached Figure 6 The inner tube 12 is fixedly installed in the internal cavity of the movable piston rod 6. The first air inlet 71 and the second air inlet 72 are both nested and fixed to the side wall of the fixed cylinder 7. The two sets of fixed cylinders 7 are symmetrically distributed about the vertical center line of the worktable 2.

[0024] The inner tube 12 is coaxially fixed in the internal cavity of the movable piston rod 6, dividing the internal space of the movable piston rod 6 into two independent air chambers: the annular cavity between the outer wall of the inner tube 12 and the inner wall of the movable piston rod 6 is the upper air passage, and the central hollow cavity of the inner tube 12 is the lower air passage; the first air inlet 71 and the second air inlet 72 are both sealed and nested on the side wall of the fixed cylinder 7, respectively connecting the upper air passage and the lower air passage; the two sets of fixed cylinders 7 are symmetrically distributed about the vertical center line of the worktable 2, so that the clamping force and the air passage driving pressure on both sides are consistent, ensuring that the magnet is clamped with uniform force and that no skew or displacement occurs during the detection process.

[0025] Reference Appendix Figure 4 The support rod 4 includes a connecting sleeve 41 that is fixedly connected to the outside of the CCD camera assembly 5. The outer end of the connecting sleeve 41 is rotatably connected to a telescopic rod 42 via a rotating shaft. The outer end of the telescopic rod 42 is rotatably connected to a fixing ring 43. The fixing ring 43 is rotatably sleeved on the outside of the rod body of the movable piston rod 6, which is located above the fixed cylinder 7.

[0026] The support rod 4 is a linkage transmission structure. The connecting sleeve 41 is fixedly sleeved on the outer wall of the CCD camera assembly 5 and rises and falls synchronously with the output end of the hydraulic push rod 3. The two ends of the telescopic rod 42 are respectively connected to the connecting sleeve 41 and the fixing ring 43 through the rotating shaft. The fixing ring 43 is rotatably sleeved on the upper part of the moving piston rod 6 that extends out of the fixing cylinder 7. When the electric push rod 8 drives the fixing cylinder 7 to adjust the clamping distance along the guide rod 9, the telescopic rod 42 can adaptively complete the extension and rotation of the telescopic rod and the angle rotation to compensate for the distance change of the moving piston rods 6 on both sides. At the same time, the lifting power of the hydraulic push rod 3 can be stably transmitted to the moving piston rods 6 on both sides through this structure.

[0027] Reference Appendix Figure 5 and attached Figure 6 The lower air passage includes a conical hole at the bottom of the movable piston rod 6. A conical plug 10 is fitted to the inner wall of the conical hole. The upper end of the conical plug 10 is connected to the lower inner wall of the inner tube 12 via a return spring 11. A piston rod 13 is slidably fitted to the inner side of the upper end of the inner tube 12. The upper end of the piston rod 13 is fixed to the inner wall of the top end of the inner tube 12 via a connecting spring 131. The top end of the piston rod 13 extends out of the outer side of the inner tube 12 and is rotatably connected to a rotating rod 14. The upper end of the rotating rod 14 is rotatably connected to the edge of a disc 15. The center of the disc 15 is fixedly connected to a rotating block 16. The rotation angle of the disc 15 is from 0° to 180°. The rotating block 16 is rotatably and sealingly mounted on the inner side of the upper end of the inner tube 12. The piston rod 13 is located below the rotating rod 14.

[0028] Because the bottom end of the movable piston rod 6 has a conical hole, under normal conditions, the return spring 11 pulls the conical plug 10 upward, so that the outer wall of the conical plug 10 is tightly fitted to the inner wall of the conical hole, and the lower air passage is in a closed state. When the movable piston rod 6 slides downward along the fixed cylinder 7, the gas in the lower cavity of the fixed cylinder 7 is pressurized, pushing the conical plug 10 upward, compressing the return spring 11 to open the conical hole, and the pressurized gas enters the lower air passage cavity of the inner tube 12. The air pressure pushes the piston vertical rod 13 to slide upward along the inner wall of the inner tube 12, compressing the connecting spring 131. The top end of the piston vertical rod 13 drives the lower end of the rotating rod 14 to move upward, and the upper end of the rotating rod 14 pushes the circular... The edge of the disc 15 causes the disc 15 to rotate around the rotating block 16 as the axis, which in turn drives the limiting block 17 to complete the rotation from 0° to 180°, so that the lower end face of the magnet can be flipped to face upward for detection. When the moving piston rod 6 slides upward, the air pressure in the lower air passage decreases, the connecting spring 131 rebounds and drives the piston vertical rod 13 to move down and reset. The reset spring 11 pushes the conical plug 10 to re-close the conical hole, and the disc 15 drives the limiting block 17 to rotate and reset. The rotating block 16 is sealed and rotated inside the upper end of the inner tube 12 to ensure the airtightness of the lower air passage. The piston vertical rod 13 is always located below the rotating rod 14 to ensure the stability of the transmission direction.

[0029] Reference Appendix Figure 5 The upper air passage includes a one-way air inlet on the upper side wall of the movable piston rod 6. The one-way air inlet is connected to the annular gap between the movable piston rod 6 and the inner tube 12. The annular gap is connected to the air inlet end of the air supply pipe 18. The air outlet end of the air supply pipe 18 is divided into two paths, which are connected to the limiting mechanism and the rolling mechanism respectively.

[0030] The upper air passage is the driving air path for limiting and rotating actions. The upper side wall of the moving piston rod 6 has a one-way air inlet, which allows external gas to flow into the annular gap in one direction only, preventing gas leakage in the reverse direction. When the moving piston rod 6 slides upward along the fixed cylinder 7, the volume of the cavity in the upper part of the fixed cylinder 7 decreases, and the gas in the annular upper air passage is pressurized and outputs pressurized gas to the outside through the air inlet end of the air supply pipe 18. The air outlet end of the air supply pipe 18 is divided into two independent branches, which are connected to the limiting mechanism and the rolling mechanism respectively, and simultaneously deliver driving air pressure to the two sets of mechanisms. When the moving piston rod 6 slides downward, the volume of the annular gap increases to form a negative pressure, and the one-way air inlet automatically opens to replenish gas, maintain the stability of the air pressure in the upper air passage, and ensure the continuity of the air path drive during the reciprocating motion of the piston rod.

[0031] Reference Appendix Figure 7The limiting mechanism includes a first telescopic member 19 connected to one outlet end of the gas supply pipe 18. An arc-shaped block 20 is fixedly connected to the bottom of the first telescopic member 19. A roller is rotatably arranged at the bottom of the arc-shaped block 20. The bottom of the roller is in contact with the edge of the end face of the circular sintered NdFeB magnet. Two sets of arc-shaped blocks 20 are symmetrically distributed about the transverse center line of the limiting block 17. The first telescopic member 19 includes a vertical cylinder 191 fixed inside the limiting block 17. An extension rod 192 is slidably arranged inside the vertical cylinder 191. The top of the extension rod 192 is connected to the inner wall of the top of the vertical cylinder 191 through a cooperating spring 193.

[0032] The limiting mechanism is used for vertical positioning during the rotation of the magnet. One branch of the gas supply pipe 18 is connected to the top cavity of the vertical cylinder 191 of the first telescopic member 19. The vertical cylinder 191 is vertically fixed to the top of the inner side of the limiting block 17. In the initial state, the extension rod 192 is supported downward by the spring 193, so that the arc block 20 is in the retracted high position. When pressurized gas is introduced into the gas supply pipe 18, the air pressure pushes the extension rod 192 to slide downward along the inner wall of the vertical cylinder 191, compressing the spring 193 and causing the arc block 20 to extend downward. The two sets of arc blocks 20 are symmetrically distributed about the transverse center line of the limiting block 17. The bottom rollers are simultaneously attached to the upper edge of the circular magnet, forming a vertical limit on the magnet and preventing the magnet from moving up and down during rotation. The rollers at the bottom of the arc block 20 can rotate synchronously with the magnet, limiting the magnet without hindering its circumferential rotation and avoiding hard contact that could scratch the magnet's surface coating.

[0033] Reference Appendix Figure 8 and attached Figure 10 The rolling mechanism includes a roller 21 rotatably disposed inside the limiting block 17. The roller 21 has a spiral groove 211 inside. A spiral block 23 is spirally connected to the inner side of the spiral groove 211. The top of the spiral block 23 is fixedly connected to the output end of the second telescopic member 22. The air inlet end of the second telescopic member 22 is connected to the other air outlet end of the air supply pipe 18.

[0034] The rolling mechanism is used to drive the magnet to rotate circumferentially. The roller 21 is rotatably mounted on the inner side wall of the limiting block 17 via a rotating shaft. The roller 21 has a spiral groove 211 axially formed inside. The second telescopic member 22 is vertically fixed inside the limiting block 17. Its output end is fixedly connected to the top of the spiral block 23. The spiral block 23 extends into the spiral groove 211 and forms a spiral transmission engagement. When the other branch of the gas supply pipe 18 supplies pressurized gas to the second telescopic member 22, the output end of the second telescopic member 22 drives the spiral block 23 to perform linear telescopic motion. When the spiral block 23 moves along the spiral groove 211, the linear motion is converted into the circumferential rotation of the roller 21 through the transmission action of the spiral pair. The outer wall of the roller 21 is in contact with the circumferential side wall of the magnet. Relying on static friction, the circular sintered NdFeB magnet is driven to rotate synchronously circumferentially, so that the CCD camera assembly 5 can continuously acquire the surface image of the entire circumferential side wall of the magnet, realizing the detection of the side wall without dead angles.

[0035] Reference Appendix Figure 9 and attached Figure 10 The second telescopic member 22 has the same internal structure as the first telescopic member 19. The stiffness coefficient of the spring 193 inside the second telescopic member 22 is greater than that of the spring 193 inside the first telescopic member 19.

[0036] The internal structure of the second telescopic component 22 is completely identical to that of the first telescopic component 19, both consisting of a vertical cylinder 191, an extension rod 192, and a cooperating spring 193. The stiffness coefficient of the cooperating spring 193 inside the second telescopic component 22 is greater than that inside the first telescopic component 19. When the air pressure in the upper airway gradually increases, because the stiffness of the cooperating spring 193 in the first telescopic component 19 is lower, the air pressure will first overcome its spring force to push the extension rod 192 out, prioritizing the limiting clamping of the magnet. After the limiting action is completed and the air pressure continues to increase, the air pressure then overcomes the spring force of the second telescopic component 22 to drive the spiral block 23 to move, triggering the rotation of the roller 21.

[0037] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A magnetically shielded sintered NdFeB magnet surface defect detection device, comprising a detection box (1) and a worktable (2) fixed therein, wherein a CCD camera assembly (5) for acquiring images of circular sintered NdFeB magnets is provided above the worktable (2), characterized in that: The CCD camera assembly (5) has a magnetic shielding cover (51) nested on the outside of the camera; a hydraulic push rod (3) is fixedly mounted on the rear side of the worktable (2) and its output end is fixedly connected to the bottom of the CCD camera assembly (5), and two sets of moving piston rods (6) are symmetrically connected on the outside of the output end via a support rod (4); the outer wall of the moving piston rod (6) slides against the inner wall of the fixed cylinder (7), and the outer sides of both sets of fixed cylinders (7) are fixedly connected to the output end of the electric push rod (8), and the front end of the fixed cylinder (7) is slidably sleeved on the outside of the guide rod (9) which is horizontally fixed on the upper end of the worktable (2); the end of the moving piston rod (6) that extends into the fixed cylinder (7) is provided with an inner tube (12), and the outer wall of the inner tube (12) is connected to the moving piston rod (6). An annular upper air passage is formed between the inner walls of the moving piston rod (6), and the inner cavity of the inner tube (12) is the lower air passage; the side wall of the fixed cylinder (7) is respectively fitted with a first air inlet (71) that connects to the upper air passage and a second air inlet (72) that connects to the lower air passage; the front end of the lower air passage is connected to a flipping mechanism, the output end of the flipping mechanism is fixedly connected to a rotating block (16), the outer end of the rotating block (16) is fixedly connected to a limiting block (17), and the two sets of limiting blocks (17) are used to clamp the magnet to be tested; the upper air passage is connected to the limiting mechanism and the rolling mechanism through the air supply pipe (18), the execution end of the limiting mechanism is two sets of symmetrical arc blocks (20), and the execution end of the rolling mechanism is a roller (21) that is rotatably set inside the limiting block (17).

2. The surface defect detection device for magnetically shielded sintered NdFeB magnets according to claim 1, characterized in that: The inner tube (12) is fixedly installed in the internal cavity of the movable piston rod (6). The first air inlet (71) and the second air inlet (72) are both nested and fixed on the side wall of the fixed cylinder (7). The two sets of fixed cylinders (7) are symmetrically distributed about the vertical center line of the worktable (2).

3. The surface defect detection device for magnetically shielded sintered NdFeB magnets according to claim 1, characterized in that: The support rod (4) includes a connecting sleeve (41) fixedly connected to the outside of the CCD camera assembly (5). The outer end of the connecting sleeve (41) is rotatably connected to a telescopic rod (42) via a rotating shaft. The outer end of the telescopic rod (42) is rotatably connected to a fixing ring (43). The fixing ring (43) is rotatably sleeved on the outside of the rod body of the movable piston rod (6) above the fixed cylinder (7).

4. The surface defect detection device for magnetically shielded sintered NdFeB magnets according to claim 1, characterized in that: The lower air passage includes a conical hole at the bottom of the movable piston rod (6). A conical plug (10) is fitted to the inner wall of the conical hole. The upper end of the conical plug (10) is connected to the lower inner wall of the inner tube (12) by a return spring (11). A piston rod (13) is fitted to the inner side of the upper end of the inner tube (12). The upper end of the piston rod (13) is fixed to the top inner wall of the inner tube (12) by a connecting spring (131). The top end of the piston rod (13) extends out of the outer side of the inner tube (12) and is rotatably connected to a rotating rod (14). The upper end of the rotating rod (14) is rotatably connected to the edge of the disc (15). The center of the disc (15) is fixedly connected to the rotating block (16).

5. The surface defect detection device for magnetically shielded sintered NdFeB magnets according to claim 4, characterized in that: The rotation angle range of the disk (15) is 0° to 180°, the rotating block (16) is sealed and rotated inside the upper end of the inner tube (12), and the piston rod (13) is located below the rotating rod (14).

6. The surface defect detection device for magnetically shielded sintered NdFeB magnets according to claim 1, characterized in that: The upper air passage includes a one-way air inlet on the upper side wall of the movable piston rod (6). The one-way air inlet is connected to the annular gap between the movable piston rod (6) and the inner tube (12). The annular gap is connected to the air inlet end of the air supply pipe (18). The air outlet end of the air supply pipe (18) is divided into two paths, which are connected to the limiting mechanism and the rolling mechanism respectively.

7. The surface defect detection device for magnetically shielded sintered NdFeB magnets according to claim 6, characterized in that: The limiting mechanism includes a first telescopic member (19) connected to one outlet end of the gas pipeline (18). An arc-shaped block (20) is fixedly connected to the bottom of the first telescopic member (19). A roller is rotatably provided at the bottom of the arc-shaped block (20). The bottom of the roller is attached to the edge of the end face of the circular sintered NdFeB magnet. The two sets of arc-shaped blocks (20) are symmetrically distributed about the transverse center line of the limiting block (17).

8. The surface defect detection device for magnetically shielded sintered NdFeB magnets according to claim 7, characterized in that: The first telescopic member (19) includes a vertical cylinder (191) fixed inside the limiting block (17). An extension rod (192) is slidably disposed on the inner side of the vertical cylinder (191). The top of the extension rod (192) is connected to the inner wall of the top of the vertical cylinder (191) through a cooperating spring (193).

9. The surface defect detection device for magnetically shielded sintered NdFeB magnets according to claim 6, characterized in that: The rolling mechanism includes a roller (21) rotatably disposed inside the limiting block (17). The roller (21) has a spiral groove (211) inside. A spiral block (23) is spirally connected to the inner side of the spiral groove (211). The top of the spiral block (23) is fixedly connected to the output end of the second telescopic member (22). The air inlet end of the second telescopic member (22) is connected to the other air outlet end of the air supply pipe (18).

10. The surface defect detection device for magnetically shielded sintered NdFeB magnets according to claim 9, characterized in that: The second telescopic member (22) has the same internal structure as the first telescopic member (19). The stiffness coefficient of the spring (193) inside the second telescopic member (22) is greater than that of the spring (193) inside the first telescopic member (19).

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