Model placenta pin insulation structure and positioning method

Abstract

The invention provides a model placenta pin positioning method, which comprises the following steps of: arranging a reference plate on the surface of a model placenta by adopting a non-contact visual detection system, acquiring a projection array of a positioning pin on the reference plate through a light source group with a preset inclination angle and a visual acquisition module, extracting projection characteristics through a processing unit, and comparing the projection characteristics with a reference model, and the positioning pins exceeding the position tolerance are automatically identified and marked, and accurate repair is guided. According to the insulating structure adopting the positioning method, the insulating friction ring and the pin sleeve are arranged in the annular positioning hole group of the mold placenta, so that reliable insulating isolation is formed between the positioning pin and the mold placenta. By the adoption of the technical scheme, insulation protection is conducted between the positioning pin and the mold placenta, and the welding arc damage probability is effectively reduced; through the combination of optical projection and image processing, the problems that traditional contact detection is low in precision and insufficient in efficiency, and industrial vision is prone to being affected by welding interference and perspective distortion are solved, and the blade positioning precision and the welding quality are improved.

Description

Technical Field

[0001] This invention relates to the field of blade positioning and machining tooling, specifically to an insulating structure and positioning method for a molded placental pin. Background Technology

[0002] During blade machining, the blades need to be positioned on a mold base before welding. The accuracy of the welding position directly determines the aerodynamic performance, operational stability, and service life of the entire machine. During blade positioning, a number of locating pins, arranged in a ring, are required, arranged in multiples according to the number of blades. These pins must be inserted into pre-set openings in the mold base. During positioning, the openings must be perpendicular to the mold base wall thickness. However, the mold base surface is curved, which places high demands on the positioning holes. If the positioning holes are not perpendicular to the mold base wall thickness, the diameter of the locating pins will also affect the positioning accuracy. Furthermore, if the locating pin position deviation exceeds the allowable range, it will cause blade attitude shift, leading not only to abnormal arc discharge during spot welding and wear on tooling components such as the locating pins, mold base, and centering plate, but also to misalignment of the blades with the inner and outer rings, resulting in defects such as porosity and incomplete fusion. Furthermore, if a conductive path is formed between the locating pin and the mold plate, the current will break down the air and generate a high-temperature arc when welding the blades, causing wear on the locating pin and the mold plate, while also interfering with the distribution of welding energy, resulting in weld quality defects.

[0003] Current methods for testing the accuracy of locating pins after installation typically involve mechanical contact positioning, where a few pins are randomly selected and inspected manually using tools such as calipers. However, this method suffers from poor accuracy and is time-consuming and labor-intensive. Some manufacturers use industrial cameras to find positioning defects, but this method has poor anti-interference capabilities. For multiple sets of ring-shaped locating pins, the inconsistent scaling ratios of the images of different rings directly lead to increased errors in deviation calculation. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of the above-mentioned technologies by proposing an insulating structure and positioning method for mold plate pins. This invention aims to solve the problems of mold plate positioning holes being prone to tilting, which leads to tilting of the positioning pins and affects positioning accuracy, and the formation of a passage between the positioning pins and the mold plate, resulting in abnormal arc discharge during spot welding.

[0005] This invention provides a method for positioning a placental pin, comprising the following steps: S1: Positioning pin assembly: The molded placer 1 has multiple sets of positioning holes arranged in a ring on its surface. Positioning pins are inserted into the positioning holes, and the blades are installed and positioned based on several positioning pins in different positions. S2: Use a positioning detection mechanism to detect the position of the positioning pin. The positioning and detection mechanism includes a reference plate, a light source group, a vision acquisition module, and a processing unit; the light source group and the vision acquisition module are respectively connected to the processing unit; The reference plate is placed on the surface of the mold plate, and the positioning pin is illuminated by the light source group so that the positioning pin forms a projection array on the reference plate. The vision acquisition module acquires the image of the projection array and transmits it to the processing unit. The processing unit extracts projection features from the image of the projection array, compares the projection features with the reference projection model, and determines whether the positioning pins meet the requirements of blade positioning based on the comparison results. Positioning pins that do not meet the requirements are filtered out and marked. S3: For the marked locating pins and corresponding locating holes, reprocess or replace them according to the comparison results, and reinstall them. Repeat step S2 for re-inspection of the reinstalled locating pins.

[0006] Preferably, the positioning holes are perpendicular to the wall thickness direction of the mold plate, and the positioning holes are arranged in a ring with at least three sets, and each set of positioning holes is staggered to position the blade.

[0007] Preferably, in step S2, the reference plate is placed on the surface of the molded placenta, and the reference plate is located between adjacent positioning pin ring groups. The light source group consists of several light sources, each of which is located above the equally spaced intervals of the molded placenta. The visual acquisition module is located directly above the center of the molded placenta.

[0008] Reference plate 3 is a ring-shaped plate structure.

[0009] Preferably, before detecting the position of the positioning pin in step S2, the method further includes: Turn on the light source to illuminate the target area and make a preliminary judgment on whether the projections of all the positioning pins can be projected onto the corresponding positions of the reference plate. If there are positioning pins that cannot be projected, the reference plate needs to be calibrated. If there are still positioning pins that cannot be projected after the reference plate is calibrated, it is confirmed that the positioning pin and its corresponding positioning hole do not meet the requirements.

[0010] Preferably, in step S4, the processing unit extracts projection features including one or more of the following: the center coordinates of the projection circle, the lengths of the major and minor axes, the eccentricity of the ellipse, and the integrity of the contour.

[0011] Preferably, in step S4, after the processing unit extracts the projection features, it corrects the coordinate data distortion using a correction formula, which is:

[0012] k is the correction coefficient, f is the camera focal length, R is the radius of the positioning pin ring, H is the camera height, and α is the light source tilt angle; The coordinate data after distortion correction by formula is compared with the preset center coordinates of the reference projection model to calculate its radial deviation and tangential deviation. When the radial deviation and tangential deviation are greater than the preset range of their respective reference projection models, it is determined that the projection of the positioning pin exceeds the preset threshold and is marked.

[0013] Preferably, the positioning pin is inserted into the positioning hole through an insulating structure. The insulation structure includes: An insulating pin sleeve is installed inside the positioning hole, and a positioning pin is inserted into the insulating pin sleeve. A friction ring is provided between the outer wall of the insulating pin sleeve and the inner wall of the positioning hole. A limiting ring is connected to the top edge of the insulating pin sleeve to restrict the movement of the friction ring. Both the insulating pin sleeve and the positioning pin are coated with an insulating layer. The friction ring is made of insulating material and has serrated ends along its axial direction. The inner wall of the pin sleeve is threaded, and the end of the locating pin located inside the pin sleeve is threaded to match the thread on the inner wall of the pin sleeve.

[0014] Compared with existing technologies, it has the following beneficial effects: This invention provides a method for positioning pins on a mold plate. It employs a non-contact optical inspection system, setting a high-precision reference plate on the mold plate surface. Using a light source group distributed at a preset tilt angle and a vertically centered vision acquisition module, it acquires a projection array image of the positioning pin on the reference plate. Combined with a geometric correction model including parameters such as tilt angle and height, it digitally compensates for perspective distortion. The processing unit extracts multi-dimensional features such as projection coordinates and contour ellipticity and compares them with the preset reference model with high precision. It automatically identifies and marks positioning pins with out-of-tolerance positions, generating rework guidance information including specific deviation amounts and adjustment directions. The pin insulation structure positioned using this method incorporates a composite structure of an insulating friction ring and a metal pin sleeve within a ring-shaped group of positioning holes on the mold plate. This allows the positioning pin to be fixed within the pin sleeve via a threaded connection, simultaneously forming reliable electrical insulation isolation from the mold plate body. This effectively blocks the current conduction path during welding, fundamentally preventing abnormal wear and ablation of key components such as the positioning pin, mold plate, and centering plate due to arc discharge. Using the above technical solution… 1. By using anti-interference optical projection detection and digital image processing technology, the shortcomings of traditional manual sampling inspection, such as low efficiency and insufficient accuracy, as well as the susceptibility of direct shooting by industrial cameras to strong welding light and metal spatter, are overcome, effectively improving the batch inspection efficiency and consistency of ring-shaped distributed positioning pin groups. 2. By detecting and reworking problematic molded placentas, we can identify and adjust potential issues with the molded placenta positioning holes, effectively improving the efficiency of molded placenta positioning holes. 3. The high-precision and high-reliability positioning of the blades on the mold platen ensures accurate welding positions between the blades and the inner and outer rings, effectively reducing welding defects such as porosity and lack of fusion, and effectively improving the overall aerodynamic performance, operational stability and service life of the machine. 4. Through the physical isolation and buffering effect of the insulating friction ring, the risk of damage to the tooling by the welding arc is reduced, and the tightness of the fit between the pin sleeve and the positioning hole is enhanced, effectively suppressing the loosening of the positioning pin. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only preferred embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the insulation structure of a molded placental pin according to the present invention; Figure 2 This is a schematic diagram of the positioning pin, pin sleeve, and friction ring of the present invention; Figure 3 This is a schematic diagram of the locating pin thread of the present invention; Figure 4 This is a schematic diagram of the reference plate of the present invention; Figure 5 This is a schematic diagram of the testing mechanism of the present invention; Figure 6 This is a schematic diagram of the light source group and visual acquisition module of the present invention; Figure 7 This is a flowchart of a method for positioning a placental pin according to the present invention.

[0017] In the figure, mold plate-1; positioning hole-11; positioning pin-2; reference plate-3; light source group-4; vision acquisition module-5; processing unit-6; pin sleeve-71; friction ring-72; limit ring-73. Detailed Implementation

[0018] To better understand the structure, functional features, and advantages of the present invention, preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings: Example: like Figures 1 to 7 As shown, the present invention provides a method for positioning a placental pin, comprising the following steps: S1: Multiple sets of positioning holes 11 arranged in a ring are formed on the surface of the mold base 1. Positioning pins 2 are inserted into the positioning holes 11, and the blades are installed and positioned based on the positioning pins 2 in different positions. The positioning holes 11 must be perpendicular to the wall thickness direction of the mold base 1. At least three sets of positioning holes 11 are arranged in a ring, and each set of positioning holes is staggered to position the blades. The blades are positioned within the staggered positions of each set of positioning holes. Of course, more sets can be used for positioning, but three sets are the minimum.

[0019] S2: Position detection of positioning pin 2 is performed using a positioning detection mechanism. The positioning and detection mechanism includes a reference plate 3, a light source group 4, a vision acquisition module 5, and a processing unit 6; the light source group 4 and the vision acquisition module 5 are respectively connected to the processing unit 6; The reference plate 3 is placed on the surface of the mold plate 1, and the positioning pin 2 is illuminated by the light source group 4 so that the positioning pin 2 forms a projection array on the reference plate 3. The vision acquisition module 5 acquires the image of the projection array and transmits it to the processing unit 6. The processing unit 6 extracts projection features based on the image of the projection array, compares the projection features with the reference projection model, and determines whether the positioning pin 11 meets the requirements of blade positioning based on the comparison results. Positioning pins 11 that do not meet the requirements are filtered out and marked. The reference plate 3 is made of precision ceramic or Invar steel with a high-contrast diffuse reflection coating. It is magnetically attached to the surface of the mold plate 1 for easy position adjustment. Since the surface of the mold plate 1 is curved, the reference plate 3 can simultaneously support the projection of the positioning pins 2 on both sides. The reference plate 3 can be configured as a folded plate, forming a triangular cross-section with the surface of the mold plate 1, which can maintain stability while simultaneously projecting the positioning pins 2 on both sides. Alternatively, the same number of reference plates 4 as the set of positioning pins 2 can be used, as long as the positioning pins 2 can be projected onto the reference plate 3 and captured by the vision acquisition module 5. The specific angle of the reference plate 3 will be determined during the preliminary experimental stage.

[0020] The light source group 4 consists of several highly directional LED light sources. These light sources are arranged in a circular array above the molded placenta 1 with equal angles and radii, with the center of the molded placenta 1 as the center. This ensures that each light source can illuminate the fan-shaped area it is responsible for at the same preset tilt angle, thereby providing uniform and shadow-free lighting conditions for all the annular positioning pins 2.

[0021] The light source group 4 and the positioning pin group 2 form a specific angle (determined in preliminary experiments) to ensure that all positioning pins in this area can produce a clear, measurable projection on the reference plate 4. During installation, the light source group 5 is connected to the corresponding bracket. Using a precision level and a crosshair laser pointer, the visual acquisition module 6 is initially adjusted to the center position.

[0022] The vision acquisition module 5 uses a high-resolution industrial camera and is equipped with a telecentric lens to further suppress perspective errors. It is fixed directly above the center top of the mold plate 1 by a bracket, so that its optical axis coincides with the central axis of the mold plate, thereby establishing a unified vision coordinate system.

[0023] The processing unit 6 is electrically connected to the light source group 4 and the vision acquisition module 5. Its core functions include: synchronously triggering the light source group 4 and the vision acquisition module 5 to acquire images.

[0024] This step can quickly identify the locating pin 2 and its corresponding locating hole 11 with significant deviations. After determining the cause of the deviation, rework can be carried out quickly. If the locating hole 11 is misaligned, it can be corrected by scrapping the mold and replacing the mold base, or by enlarging the hole and inserting a sleeve. Alternatively, the locating hole can be repositioned by welding, but this method has a higher probability of defects. If the locating pin 2 is tilted, the locating pin 2, the pin sleeve 31, and the friction ring 32 can be replaced and reinstalled.

[0025] The projection features extracted by the processing unit include one or more of the following: the coordinates of the projection center, the lengths of the major and minor axes, the eccentricity of the ellipse, and the integrity of the contour. The processing unit extracts these projection features and corrects for distortion using a formula, which is:

[0026] (k is the correction coefficient, f is the camera focal length, R is the radius of the positioning pin ring, H is the camera height, and α is the light source tilt angle) The coordinate data after distortion correction by formula is compared with the preset center coordinates of the reference projection model to calculate its radial deviation and tangential deviation. When the radial deviation and tangential deviation are greater than the preset range of their respective reference projection models, it is determined that the projection of the positioning pin 2 exceeds the preset threshold and is marked.

[0027] The baseline projection model is based on the design parameters such as the annular radius of the positioning hole 11 of the mold plate 1 and the diameter of the positioning pin 2. Combined with the camera focal length of the vision system, the vertical height from the camera to the surface of the mold plate 1, and the tilt angle between the light source and the surface of the mold plate 1, the projection characteristics of each positioning pin 2 under the relatively ideal state of "no installation error and uniform light" are calculated through the geometric projection principle of the camera. These characteristics include the coordinates of the center of the circle in the pixel coordinate system, the length of the major / minor axis of the projection ellipse, and the eccentricity. This forms a preliminary theoretical projection model. A standard mold plate 1 with a processing error ≤0.3mm and a positioning pin 2 that is nearly ideally vertical and without tilt are used to form a calibration component (i.e., a template). This component is placed at the actual inspection station. The light source is turned on and the camera is triggered to acquire the projection image according to the normal inspection process. The actual projection characteristics of this component are extracted. After comparing the data with the theoretical model, the projection deviation caused by hardware installation problems such as slight offset of the camera optical axis and slight deviation of the light source angle are corrected. Finally, a "standard projection feature library" that perfectly matches the actual inspection scene is obtained.

[0028] The correction formula is used to calculate the correction coefficient k when actually inspecting the positioning pin 2. First, the camera focal length f, the radius R of the ring where the positioning pin is located, the vertical height H from the camera to the mold plate, and the light source tilt angle α of the current inspection scene are substituted into the formula to calculate the value of k. Then, k is substituted into the radial and tangential distortion correction formulas to correct the coordinate offset and shape deformation of the actual acquired positioning pin projection caused by perspective error and light source angle offset, so that the corrected projection features are closer to the actual physical position of the positioning pin. Finally, these corrected projection features are compared one by one with the pre-built reference projection model to calculate the radial deviation (the distance between the corrected coordinates and the reference coordinates), tangential deviation (angle difference), and other indicators. If the deviation exceeds the preset threshold, it can be determined that the positioning pin does not meet the blade positioning requirements.

[0029] The data from processing unit 6 is visualized by terminal software. If a positioning pin 2 exceeds the threshold, the defective pin can be visualized by highlighting it with a red ring on the software interface, and a rework list containing its location ID, deviation amount and type can be generated.

[0030] S3: For the marked positioning pin 2 and the corresponding positioning hole 11, reprocess or replace them according to the comparison results, and reinstall them. Repeat step S2 for re-inspection of the reinstalled positioning pin 2.

[0031] like Figure 1 , Figure 6 and Figure 7 As shown, the present invention provides a positioning pin 2 that is machined using an insulating structure and inserted into the positioning hole 11 using the positioning method of this application; The insulation structure includes: An insulating pin sleeve 71 is set in the positioning hole 11, and a positioning pin 2 is inserted into the insulating pin sleeve 71. A friction ring 72 is provided between the outer wall of the insulating pin sleeve 71 and the inner wall of the positioning hole 11. A limiting ring 73 for restricting the movement of the friction ring 72 is connected to the top edge of the insulating pin sleeve 71. Both the insulating pin sleeve 71 and the positioning pin 2 are coated with an insulating layer.

[0032] The friction ring 72 is made of insulating material and its two ends in the axial direction are serrated. The inner wall of the pin sleeve 71 is threaded, and the end of the positioning pin 2 located inside the pin sleeve 71 is provided with a thread that matches the thread on the inner wall of the pin sleeve 71.

[0033] The friction ring 72 is made of a hard insulating material, such as polyimide, which is not only wear-resistant but also heat-resistant, or polyetheretherketone (PEEK). Its axial ends are serrated, and the serrations provide better friction compared to the flat surface, reducing the probability of the locating pin 2 being pulled out of the locating hole 11. Both the pin sleeve 71 and the locating pin 2 are made of metal, such as high-carbon steel. The limiting ring 77 is made of the same material as the friction ring 72, and the limiting ring 77 is interference-fitted or grooved with the friction ring 72. The limiting ring 77 restricts the up-and-down sliding of the friction ring 72 and insulates the edge of the pin sleeve 71. The locating pin 71 is insulated from the mold plate 1. During welding, if the metal locating pin 2 and pin sleeve 71 are connected to the mold plate 1, an illegal parallel circuit will be formed. When current flows through the tiny contact points between these components, it will generate enormous heat due to contact resistance and ionize the air, thus generating a secondary arc inside the tooling and producing high temperatures, instantly burning the surfaces of the locating pin 2, pin sleeve 71, and mold plate 1, causing permanent damage. By blocking this current path through the insulating layer and friction ring 32, the current is forced to flow back only through the preset blade-mold placenta 1 main path, thereby reducing the possibility of arcing on the tooling.

[0034] The inner wall of the pin sleeve 71 is threaded, and the outer wall has a pattern to increase friction. Both the inner and outer walls of the friction ring 72 have patterns to enhance friction. The portion of the locating pin 2 inside the pin sleeve 71 is threaded and threadedly connected to the pin sleeve 71. The portion of the locating pin 2 outside the pin sleeve 71 is smooth and used for positioning. Both the locating pin 2 and the pin sleeve 31 are coated with an insulating layer, which is a thermally sprayed ceramic coating, such as an alumina coating, offering good wear resistance and high hardness.

[0035] The working principle of the positioning method for molded placer pins in this application is as follows: After the positioning pins 2 are installed, a reference plate 3 is placed. After the reference plate 3 is calibrated, the light source group 4 located above the molded placer 1 illuminates it at a preset tilt angle, so that all the positioning pins 2 project onto the reference plate 3 which is set in a ring. The vision acquisition module 5 directly above the molded placer 1 acquires the image of the projection array and transmits it to the processing unit 6. The processing unit 6 extracts the geometric features of each projection, corrects it with an algorithm, and compares it with the preset reference model to accurately identify the positioning pins 2 with verticality or position deviations. The pins 2 are marked on the software interface and on the physical site to guide accurate rework, thereby ensuring that the positioning reference formed by all the positioning pins 2 meets the high precision requirements of blade installation. The insulating structure of the pin based on this method is as follows: an insulating friction ring 72 embedded between the inner wall of the positioning hole 11 and the outer wall of the pin sleeve 71 forms the primary insulating barrier; an insulating coating applied to the surfaces of the pin sleeve 71 and the positioning pin 2 forms the secondary insulating barrier; the two work together to ensure that the positioning pin 2 is completely electrically isolated from the mold plate 1 while being fixed to it by the pin sleeve 71, thereby effectively preventing the current from forming an abnormal arc through the positioning pin 2 during subsequent blade welding and protecting the tooling from electrolytic corrosion damage.

[0036] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technology of the present invention without departing from the scope of the present invention are within the protection scope of the present invention.

Claims

1. A method for positioning a placental pin, characterized in that, Includes the following steps: S1: Positioning pin assembly: The molded placer (1) has multiple sets of positioning holes (11) arranged in a ring on its surface. Positioning pins (2) are inserted into the positioning holes (11) to achieve the installation and positioning of the blade based on the positioning pins (2) in different positions. S2: The position of the positioning pin (2) is detected using a positioning detection mechanism. The positioning detection mechanism includes a reference plate (3), a light source group (4), a vision acquisition module (5), and a processing unit (6); the light source group (4) and the vision acquisition module (5) are respectively connected to the processing unit (6); The reference plate (3) is placed on the surface of the mold plate (1), and the positioning pin (2) is irradiated by the light source group (4) so ​​that the positioning pin (2) forms a projection array on the reference plate (3). The vision acquisition module (5) acquires the image of the projection array and transmits it to the processing unit (6). The processing unit (6) extracts projection features based on the image of the projection array, compares the projection features with the reference projection model, and determines whether the positioning pin (11) meets the requirements of blade positioning based on the comparison result. The positioning pins (11) that do not meet the requirements are filtered out and marked. S3: The marked positioning pin (2) and the corresponding positioning hole (11) are reprocessed or replaced according to the comparison results and reinstalled. The reinstalled positioning pin (2) is then re-inspected by repeating step S2.

2. The method for positioning the placental pin according to claim 1, characterized in that, The positioning hole (11) needs to be perpendicular to the wall thickness direction of the mold plate (1). The positioning hole (11) is arranged in a ring with at least three sets, and each set of positioning holes is staggered to position the blade.

3. The method for positioning the placental pin according to claim 1, characterized in that, In step S2, the reference plate (3) is placed on the surface of the molded placenta (1), and the reference plate (3) is located between adjacent ring groups of positioning pins (2). The light source group (4) consists of several light sources, each of which is located above the equally spaced intervals of the molded placenta (1). The visual acquisition module (5) is located directly above the center of the molded placenta (1).

4. The method for positioning the placental pin according to claim 3, characterized in that, The reference plate (3) is a ring-shaped plate structure.

5. The method for positioning the placental pin according to claim 1, characterized in that, Before the position detection of the positioning pin (2) is performed in step S2, the method further includes: Turn on the light source group (4) to illuminate and make a preliminary judgment on whether the projection of all the positioning pins (2) can be projected onto the corresponding position of the reference plate (3). If there are positioning pins (2) that cannot be projected, the reference plate (3) needs to be calibrated. If there are still positioning pins (2) that cannot be projected after the reference plate (3) is calibrated, it is confirmed that the positioning pin (2) and its corresponding positioning hole (11) do not meet the requirements.

6. The method for positioning the placental pin according to claim 5, characterized in that, In step S4, after the processing unit (6) extracts the projection features, it corrects the coordinate data distortion using a correction formula, which is: ； Where: k is the correction coefficient, f is the camera focal length, R is the radius of the positioning pin ring, H is the camera height, and α is the light source tilt angle; The coordinate data after distortion correction by formula is compared with the preset center coordinates of the reference projection model to calculate its radial deviation and tangential deviation; when the radial deviation and tangential deviation are greater than the preset range of the reference projection model, it is determined that the projection of the positioning pin (2) exceeds the preset threshold and is marked.

7. The method for positioning the placenta pin according to claim 1, characterized in that, The positioning pin (2) is inserted into the positioning hole (11) by means of an insulating structure. The insulating structure includes: An insulating pin sleeve (71) is provided in the positioning hole (11), and the positioning pin (2) is inserted into the insulating pin sleeve (71). A friction ring (72) is provided between the outer wall of the insulating pin sleeve (71) and the inner wall of the positioning hole (11). A limiting ring (73) for restricting the movement of the friction ring (72) is connected to the top edge of the insulating pin sleeve (71). Both the insulating pin sleeve (71) and the positioning pin (2) are coated with an insulating layer.

8. The molded placenta pin insulation structure according to claim 7, characterized in that, The friction ring (72) is made of insulating material and has serrated ends on both axial sides. The inner wall of the pin sleeve (71) is threaded, and the locating pin (2) is provided with a thread matching the inner wall thread of the pin sleeve (71) at one end inside the pin sleeve (71).

Images