Manufacturing method of variable-thickness multi-bent-edge thin-wall part with reinforcing groove structure

Abstract

The invention belongs to the technical field of aviation aircraft sheet metal part machining, and relates to a manufacturing method of a variable-thickness multi-bent-edge thin-wall part with a reinforcing groove structure. According to the invention, the process method of numerical control milling blanking, sheet metal forming and chemical milling is adopted to replace the process method of numerical control milling and sheet metal forming. Mechanical cutting is replaced by chemical milling, two sets of newly-designed tools are matched for forming the reinforcing groove and the bent edge, the problems that a web is wrinkled and cannot be repaired and a thickness area is distorted and deviated due to forming of the reinforcing groove are solved, the accurate appearance of a part is finally obtained, and the surface quality is improved. The method has generalizability and can be widely applied to machining of complex molded surfaces and variable-thickness thin-wall parts, and the weight of an aircraft body is further reduced while the structural use requirement is met.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation aircraft sheet metal parts processing, and relates to a method for manufacturing a variable-thickness multi-bend-edge thin-wall part with a reinforcement groove structure. Background Art

[0002] In order to adapt to the characteristics of lightweight, most aircraft frame panels and skin parts have chosen thin-walled aluminum alloy structures with a smaller thickness, and some parts even use variable thickness structures, in order to further reduce weight. At the same time, reinforcing grooves and small curved edges are set to improve their bearing capacity and meet the requirements of rigidity and strength. During the processing, for parts with small and uneven thickness, the thickness processing error is large, and the reinforcement groove structure is unevenly stressed during the forming process, which is prone to surface distortion and low overall manufacturing accuracy of the parts.

[0003] The traditional processing method for this type of parts is "CNC milling + sheet metal forming", that is, the edges and thickness are milled when the parts are unfolded, and then sheet metal forming and heat treatment are used to strengthen them. Due to the small material thickness and large thickness milling area, the residual stress is large during the milling process, the deformation is serious and difficult to correct, and the reinforcement groove forming process produces a large strain, the surrounding material flows and shows an uneven trend, resulting in severe wrinkling and difficulty in leveling the web after forming, and ultimately causing the thickness processing area to be distorted and offset, which cannot be corrected. In addition, due to the thin thickness of the parts, the hammer marks on the surface of the parts caused by sheet metal trimming are difficult to eliminate. If the whole part is polished, the aluminum layer of the parts will be damaged, thereby reducing the physical and chemical properties of the parts. Based on the above reasons, it is very difficult to process this type of parts. Summary of the invention

[0004] The purpose of the present invention is to invent a method for manufacturing a variable thickness multi-bend thin-walled part with a reinforcement groove structure, wherein the manufacturing method is to design two sets of tooling for part forming, and to use the process method of "CNC milling cutting + sheet metal forming + chemical milling cutting" to replace "CNC milling cutting + sheet metal forming". The processing method used in the present invention can solve the problem of irreparable wrinkling of the web caused by the reinforcement groove forming, as well as the distortion and offset of the thickness area, and finally achieve the purpose of obtaining the precise shape of the part and improving the surface quality.

[0005] In order to achieve the above object, the technical solution of the present invention is:

[0006] A method for manufacturing a variable-thickness multi-bend thin-wall part with a reinforced groove structure comprises three processes: CNC milling and cutting, sheet metal forming and chemical milling.

[0007] The first process: CNC milling and cutting.

[0008] This process uses the two-dimensional unfolded data set of the part as the medium, and mills out the outer edge of the part in the unfolded state for subsequent sheet metal forming. When designing the two-dimensional unfolded data set, four ears are added on both sides of the web of the part and φ5.2 positioning holes are drilled for positioning during subsequent sheet metal forming and chemical milling; considering that there is more material flow during the forming process of the reinforcement groove, in order to avoid the local edge being too small, it can be compensated by increasing the process allowance and removed after forming;

[0009] The second process: sheet metal forming.

[0010] This process forms the flat sheet into the shape of the part, including the reinforcement groove, the bend and the small reinforcement bend. The sheet metal forming is divided into two steps. The first step is to form the reinforcement groove by hydraulic forming, and the tooling used is "Mold I".

[0011] The mold I comprises a carcass, a cover plate, a positioning pin, a mold pin, a movable handle and a hanging ring.

[0012] The second forming process is to manually form the flanges on both sides of the web and the small flanges for reinforcement. The tooling used is "Mold II".

[0013] The mold II comprises a carcass, positioning pins, a mold pin, a cover plate, a side cover plate, a movable handle and a hanging ring.

[0014] The mold I is used to press the milled blank into a reinforcement groove. The tooling is designed and manufactured according to the process data, that is, based on the web surface of the part, the two side bends and the small reinforced bends thereon are unfolded to the same plane as the web. The carcass of the "molded tire I" is made into a "concave" structure, that is, the reinforcement groove profile is embedded in the carcass plane, the thickness thinning area is compensated to the same thickness as other areas, the cover plate is made into a "convex" structure, the reinforcement ribs protrude from the lower plane of the cover plate, the thickness thinning area is compensated to the same thickness as other areas, and the positioning pins are installed between the carcass and the cover plate, and their positions are consistent with the positioning holes of the CNC milling parts, which are used to position the milling parts on the tooling during forming. The mold pin is installed between the carcass and the cover plate, which is used to align the two and bear the shear force of the section, so as to prevent the relative position of the carcass and the cover plate from changing during hydraulic forming, resulting in excessive bending and breaking of the positioning pins, which causes the deviation of the part position. The movable handle is installed on the upper surface of the cover plate to facilitate the installation and unloading of the cover plate during hydraulic forming, and the lifting ring is installed on the side of the carcass for tooling lifting and transportation. The manufacturing tolerance of the above structural surface is ±0.1mm, and the roughness of the working surface is not higher than Ra1.6μm

[0015] The mold II is used to form the blank with the reinforcement groove to the latest shape of the part, and can be used to trim the part surface after heat treatment deformation. The tooling is manufactured according to the digital model of the part. Its carcass adopts a split structure, in which carcass I is designed according to the inner profile of the part's belly plate, and carcasses II and III are located on both sides of carcass I, and their edges are flush with carcass I respectively. The positioning pin is consistent with the positioning hole position of the CNC milling part, and is used to position the part on the tooling during forming. The mold pin is installed between the carcass and the cover plate, which is used to align the two and bear the shear force of the section, to prevent the relative position of the carcass and the cover plate from changing during forming, resulting in excessive bending and breaking of the positioning pin due to excessive force, causing the part position to move and deviate. The cover plate is manufactured according to the outer profile of the part's belly plate, and the side cover plate is manufactured according to the part's curved edge and the reinforced small curved edge profile on it. When carcasses I, II, and III are fully installed, they are used in conjunction with cover plates to form the bends on both sides of the parts. When carcasses II and III are removed, carcass I, cover plates, and side cover plates are used in conjunction to form two small reinforced bends on the bends. Movable handles are installed on the upper surface of the cover plates to facilitate installation and unloading of the cover plates during forming. Lifting rings are installed at appropriate locations on the carcass side and cover plates for tooling lifting and transportation. The manufacturing tolerance of the above structural profile is ±0.1mm, and the roughness of the working profile is not higher than Ra1.6μm;

[0016] The third process: chemical milling.

[0017] The part is thinned from δ0.8mm to δ0.5mm by chemical milling. Chemical milling is a process that uses chemical or electrochemical corrosion principles to dissolve the surface of metal or non-metal materials through chemical solutions to remove materials. It is suitable for surface processing of thin plate parts, especially surfaces with complex geometric shapes that are difficult to achieve mechanical processing requirements, and there are no knife marks or chips on the surface. Specifically for this part, chemical milling can obtain a uniform thinning amount.

[0018] In view of the fact that chemical milling will release the internal stress of the material and cause local deformation, the chemical milling process used in this invention is arranged after the sheet metal is formed and heat-treated and strengthened, that is, after the web reinforcement groove, the two side bends and the small reinforced bends are formed and heat-treated and quenched. The advantage of this process is that the thickness of the part does not change after the reinforcement groove is formed, and the deformation of the web caused by trimming the reinforcement groove formation will not cause the thickness range to shift or distort. Compared with the chemical milling of the flat-plate billet, the reinforcement groove, the bends and the small reinforced bends have an inhibitory effect on the chemical milling deformation, which can reduce the chemical milling deformation to a certain extent, which is conducive to maintaining the position of the thickness change area and reducing the deformation trimming amount. After the sheet metal is formed, chemical milling is performed, and the shape of the part only needs simple trimming later. Since the sheet metal is formed first and then the thickness is processed, the surface quality of the part is better, and there is no need for overall grinding, thereby ensuring the existence of the aluminum cladding layer and its good physical and chemical properties.

[0019] Beneficial effects of the present invention:

[0020] The present invention adopts the process method of "CNC milling cutting + sheet metal forming + chemical milling cutting" to replace "CNC milling cutting + sheet metal forming". Chemical milling cutting replaces mechanical cutting, and two sets of newly designed tooling are used for reinforcing groove and bending edge forming, which solves the irreparable wrinkling of the web caused by reinforcing groove forming and the distortion and offset of the thickness area, and finally obtains the precise shape of the parts and improves the surface quality. The invention is scalable and can be widely used in the processing of complex surfaces and variable thickness thin-walled parts, meeting the structural use requirements while further reducing the weight of the aircraft body. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the part appearance drawing;

[0022] Figure 2 It is a schematic diagram of the process data set;

[0023] Figure 3 This is the structural diagram of type Ⅰ;

[0024] Figure 4 This is the structural diagram of type II tire.

[0025] In the figure: 1. carcass; 2. cover plate; 3. positioning pin; 4. clamping pin; 5. movable handle; 6. lifting ring; 7. carcass; 8. positioning pin; 9. clamping pin; 10. cover plate; 11. side cover plate; 12. movable handle; 13. lifting ring. DETAILED DESCRIPTION

[0026] The manufacturing method of a variable thickness multi-bend thin-walled part with a reinforcement groove structure comprises the following steps:

[0027] Step 1: CNC milling and cutting.

[0028] This process uses the two-dimensional unfolded data set of the part as the medium, and uses a CNC three-axis machine tool to mill out the outer edge of the part in the unfolded state for subsequent sheet metal forming (the thickness is not processed, and chemical milling is used for subsequent processing). When designing the two-dimensional unfolded data set, four ears are added on both sides of the web of the part and φ5.2 positioning holes are drilled for positioning during subsequent sheet metal forming and chemical milling; considering that there is more material flow during the reinforcement groove forming process, in order to avoid the local edge being too small, it can be compensated by increasing the process allowance and removed after forming. When milling, a two-tooth milling cutter with a helix angle of less than 45° is selected to facilitate chip removal. The drill bit selects a vertex angle of 90°~110°, and the vertex angle is symmetrical on both sides. The processing accuracy ensures that the shape limit deviation is no more than 0.5mm. After the sheet metal is milled, use files and sandpaper to file and deburr the processed end face;

[0029] Step 2: Hydroforming.

[0030] This process is used to press a reinforcement groove out of the flat blank after milling. The tooling used is "Mold I" and the equipment is a rubber bag press. First, lift the cover plate 2 of "Mold I", place the milled flat blank on the tire body, insert the φ5.2 positioning hole into the positioning pin 3, fix the blank in the tire body, close the cover plate, and use the rubber pad to fully cover the workbench. Then, start the rubber bag press, and "Mold I" enters the working area with the workbench, and set the pressure value to 40MPa for hydraulic forming. Under the pressure transmitted by the rubber bag, the cover plate 2 and the tire body gradually approach each other until they are closed, and the sheet material is deformed by the force to press out the shape of the reinforcement groove. Finally, withdraw the "Mold I" from the working area with the workbench, roll up the rubber pad, remove the cover plate 2, unload the parts, inspect the surface of the parts to confirm that there are no cracks, crushing and other mechanical damage before entering the next step;

[0031] Step 3: Manual forming.

[0032] This process is used to bend the sides of the parts and form the reinforced small bends on them. The tooling used is "Mold Tire II". Since the sheet material is relatively thin, manual forming is sufficient. First, bend the sides. After connecting carcasses II and III with carcass I through the clamping pin 9, place the blank with the reinforcement groove formed on carcass I. Insert the φ5.2 positioning hole into the positioning pin 8 to fix the blank in the carcass. Close the cover plate 10 and clamp the tooling with a universal clamp. Use rubber pads, hitting plates and other tools to hit the sheet material so that the bends on both sides are close to the side of carcass I, thereby completing the bend forming. Then, remove carcasses II and III, install the side cover plate 11, use universal clamps to completely clamp the side cover plate and carcass, use rubber pads, hitting plates and other tools to hit the bends so that the ends of the bends on both sides are close to the side cover plate 11, thereby completing the reinforcement of the small bends. After forming is completed, remove the side cover plate and cover plate, and remove the parts.

[0033] Step 4: Parts quenching.

[0034] The purpose of quenching the parts is to improve the strength and hardness of the parts. Specific operation: clean the parts and put them into the air furnace heat treatment equipment. The heating temperature range is: 495℃~505℃, and the insulation time is 25min~30min. After quenching, put them into the running cold water at 10℃~40℃ to completely cool them down for no less than 2min;

[0035] Step 5: Repair quenching deformation.

[0036] Put the quenched parts into "mold II" for trimming, use the tooling "mold II", remove the carcasses II and III, put the parts into carcass I, close the cover plate 10 and the side cover plate 11, use a hammer, aluminum hammer and other tools to knock the cover plate and the side cover plate, the cover plate and the side cover plate are stressed and transfer the force to the parts, forcing the deformed parts to fit closely with them, thereby completing the reinforcement groove and bending deformation trimming. For the reinforced small bends on both sides of the bends, use a hammer, aluminum hammer or rubber plate to knock on the surface for trimming.

[0037] Step 6: Milling and cutting.

[0038] The purpose of this process is to process the thinning area on the part from 0.8mm to δ0.5mm and keep the shape and thickness of the remaining area unchanged.

[0039] The main steps include:

[0040] 6.1 Cleaning: Wipe the surface of the part with a cloth soaked in an organic solvent, and then wipe it dry with a clean cloth; the selected organic solvent should not corrode the parts;

[0041] 6.2 Apply protective glue: Brush or spray the chemical milling protective glue, the coating thickness is 0.20mm~0.50mm, and check the quality of the film after it dries. There should be no uncoated areas, bubbles, pinholes or mechanical impurities;

[0042] 6.3 Engraving: Fix the milling template on the part with the locating pin (the locating pin is coordinated with the locating pin of the part processing). According to the edge of the milling template, use a scalpel to manually carve the contour of the corrosion area, remove the protective layer of the area to be corroded, and protect the locating hole;

[0043] 6.4 Chemical milling: Place the parts in the chemical milling tank liquid, the chemical milling solution is NaOH, and the distance between the parts and the tank wall is not less than 150mm. Accurately measure the corrosion rate and record it. When the chemical milling time reaches 70% to 90% of the calculated time, take out the parts, measure the thickness of the chemical milling area, and calculate the chemical milling time of the remaining thickness [chemical milling time = (actual thickness of the chemical milling area - δ0.5mm) ÷ chemical milling rate], and continue chemical milling until the required thickness is reached;

[0044] 6.5 Inspection: After the chemical milling is completed, take out the parts, wash them with cold water, and remove the protective glue layer by manual stripping. Check whether the chemical milling quality, the thickness of the chemical milling area and the surface roughness meet the engineering requirements;

[0045] Step 7: Repair chemical milling deformation.

[0046] When the parts are chemically milled, the internal stress is released and the surface is partially distorted and deformed. Manual trimming can be used, as in step 5;

[0047] Step 8: Parts surface treatment.

[0048] The parts are anodized and painted to improve their corrosion resistance.

[0049] 8.1 Anodizing: At a temperature of 13℃-25℃ and a voltage of 13V-24V, place the parts in a sulfuric acid anodizing tank for oxidation treatment for 15min-40min, and then wash them in a cold water tank for 1min-2min;

[0050] 8.2 Potassium dichromate sealing: At a temperature of 90℃-100℃, the parts are treated in a potassium dichromate sealing tank for 15min-20min, washed in a 40℃-60℃ warm water tank for 1min-2min, blown dry with compressed air, or dried in a drying tank at 40℃-70℃ for 10min-20min;

[0051] 8.3 Painting: Use the prepared paint for spraying within the validity period, and the thickness of the paint should be controlled within the range of 25μm-35μm. The painted parts are dried. The drying conditions are: room temperature: drying for 7 days; or 40℃-50℃, drying for 10h-12h; or 65℃-75℃, drying for 2h-4h; or 100℃-110℃, drying for 1h-3h.

[0052] Complete the above steps to obtain the final part.

Claims

1. A method for manufacturing a variable thickness multi-bend thin-walled part with a reinforcement groove structure, characterized in that: The steps include: Step 1: CNC milling and cutting; This process uses the two-dimensional unfolded data set of the part as the medium, and uses a CNC three-axis machine tool to mill out the outer edge of the part in the unfolded state for subsequent sheet metal forming; Step 2: Hydroforming; This process is used to press a reinforcing groove out of a flat blank after milling. The tooling used is "mold Ⅰ" and the equipment is a rubber bag press. First, lift the cover plate (2) of the "mold Ⅰ", place the flat blank after milling on the tire body, insert the φ5.2 positioning hole into the positioning pin (3), fix the blank in the tire body, close the cover plate, and use a rubber pad to fully cover the workbench. Then, start the rubber bag press, and the "mold Ⅰ" enters the working area with the workbench, and the pressure value is set to 40MPa for hydraulic forming. Under the pressure transmitted by the rubber bag, the cover plate (2) and the tire body gradually approach each other until they are closed, and the sheet material is deformed by force to press out the shape of the reinforcing groove. Finally, the "mold Ⅰ" is withdrawn from the working area with the workbench, the rubber pad is rolled up, the cover plate (2) is removed, the parts are unloaded, and the surface of the parts is inspected to confirm that there are no cracks, crushing and other mechanical damage before entering the next step. Step 3: Manual forming; This process is used to form the bending edges on both sides of the part and the small reinforced bending edges thereon. The tooling used is "molded tire II". Since the sheet material is relatively thin, manual forming can be used. First, the bending edges on both sides are formed. After the tire bodies II and III are connected to the tire body I by the mold pin (9), the blank with the reinforcement groove formed is placed on the tire body I, and the φ5.2 positioning hole is inserted into the positioning pin (8) to fix the blank in the tire body. The cover plate (10) is closed, and the tooling is clamped with a universal clamp. The sheet material is hit with a rubber pad and a plate hitting tool to make the bending positions on both sides close to the side of the tire body I, thereby completing the bending forming. Then, the tire bodies II and III are removed, and the side cover plates (11) are installed. The side cover plates and the tire body are completely clamped with a universal clamp. The rubber pad and a plate hitting tool are hit with the bending positions to make the ends of the bending edges on both sides close to the side cover plates (11), thereby completing the strengthening small bending forming. After the forming is completed, the side cover plates and the cover plates are removed, and the parts are removed. Step 4: Parts quenching; The parts are quenched to improve their strength and hardness; Step 5: Repair quenching deformation; The quenched parts are placed in "mold II" for trimming. The tooling is "mold II". Carcass II and carcass III are removed. The parts are placed in carcass I. The cover plate (10) and the side cover plate (11) are closed. The cover plate and the side cover plate are struck with a hammer or an aluminum hammer. The cover plate and the side cover plate are subjected to force and transmit the force to the parts, forcing the deformed parts to be closely attached thereto, thereby completing the trimming of the reinforcement groove and the bending edge deformation. For the small reinforcing bending edges on both sides, the surfaces are trimmed by striking them with a hammer, an aluminum hammer or a rubber beating plate. Step 6: Chemical milling and cutting; Step 7: Repair chemical milling deformation; When the parts are chemically milled, the internal stress is released and the surface is partially distorted and deformed. Manual trimming can be used, as in step 5; Step 8: Parts surface treatment; The parts are anodized and painted to improve their corrosion resistance.

2. A method for manufacturing a variable thickness multi-bend thin-walled part with a reinforcement groove structure as claimed in claim 1, characterized in that: The specific operation of step six is ​​as follows: 6.1 Cleaning: Wipe the surface of the part with a cloth soaked in an organic solvent, and then wipe it dry with a clean cloth; the selected organic solvent should not corrode the parts; 6.2 Apply protective glue: Brush or spray the chemical milling protective glue, the coating thickness is 0.20mm ~ 0.50mm, and check the quality of the film after it is dry; there should be no uncoated areas, bubbles, pinholes or mechanical impurities; 6.3 Engraving: Fix the milling template on the part with the locating pins; follow the edge of the milling template and use a scalpel to manually carve out the contour of the corrosion area, remove the protective layer of the area to be corroded, and protect the locating holes; 6.4 Chemical milling: Put the parts into the chemical milling tank liquid, the chemical milling solution is NaOH, the distance between the parts and the tank wall is not less than 150mm, accurately measure the corrosion rate and record it; when the chemical milling time reaches 70% to 90% of the calculated time, take out the parts, measure the thickness of the chemical milling area, and calculate the chemical milling time of the remaining thickness [chemical milling time = (measured thickness of the chemical milling area - δ0.5mm) ÷ chemical milling rate], continue chemical milling until the required thickness is reached; 6.5 Inspection: After completing chemical milling, take out the parts, wash them with cold water, and remove the protective glue layer by manual stripping. Inspect whether the chemical milling quality, thickness of the milling area and surface roughness meet the engineering requirements.

3. A method for manufacturing a variable thickness multi-bend thin-walled part with a reinforcement groove structure as claimed in claim 1, characterized in that: The specific operations of step eight are as follows: 8.1 Anodizing: At a temperature of 13℃-25℃ and a voltage of 13V-24V, place the parts in a sulfuric acid anodizing tank for oxidation treatment for 15min-40min, and then wash them in a cold water tank for 1min-2min; 8.2 Potassium dichromate sealing: At a temperature of 90℃-100℃, the parts are treated in a potassium dichromate sealing tank for 15min-20min, washed in a 40℃-60℃ warm water tank for 1min-2min, blown dry with compressed air, or dried in a drying tank at 40℃-70℃ for 10min-20min; 8.3 Painting: Use the prepared paint for spraying within the validity period. The thickness of the paint should be controlled within the range of 25μm-35μm. The painted parts should be dried. The drying conditions are: room temperature: drying for 7 days; or 40℃-50℃, drying for 10h-12h; or 65℃-75℃, drying for 2h-4h; or 100℃-110℃, drying for 1h-3h.

4. A method for manufacturing a variable thickness multi-bend thin-walled part with a reinforcement groove structure as claimed in claim 1 or 2, characterized in that: The specific operation of step 4 is as follows: Clean the parts and put them into the air furnace heat treatment equipment. The heating temperature range is: 495℃~505℃, and the insulation time is 25min~30min. After quenching, put them into running cold water at 10℃~40℃ to cool them completely for no less than 2min.

5. A method for manufacturing a variable thickness multi-bend thin-walled part with a reinforcement groove structure as claimed in claim 3, characterized in that: The specific operation of step 4 is as follows: Clean the parts and put them into the air furnace heat treatment equipment. The heating temperature range is: 495℃~505℃, and the insulation time is 25min~30min. After quenching, put them into running cold water at 10℃~40℃ to cool them completely for no less than 2min.

6. A method for manufacturing a variable thickness multi-bend thin-walled part with a reinforcement groove structure as claimed in claim 1, 2 or 5, characterized in that: The tire mold I comprises a tire body (1), a cover plate (2), a positioning pin (3), a mold pin (4), a movable handle (5), and a hanging ring (6); the tire mold II comprises a tire body (7), a positioning pin (8), a mold pin (9), a cover plate (10), a side cover plate (12), a movable handle (12), and a hanging ring (13); the tire body (1) of the tire mold I is made into a "concave" structure, and the cover plate (2) is made into a "convex" structure.

7. A method for manufacturing a variable thickness multi-bend thin-walled part with a reinforcement groove structure as claimed in claim 3, characterized in that: The tire mold I comprises a tire body (1), a cover plate (2), a positioning pin (3), a mold pin (4), a movable handle (5), and a hanging ring (6); the tire mold II comprises a tire body (7), a positioning pin (8), a mold pin (9), a cover plate (10), a side cover plate (12), a movable handle (12), and a hanging ring (13); the tire body (1) of the tire mold I is made into a "concave" structure, and the cover plate (2) is made into a "convex" structure.

8. A method for manufacturing a variable thickness multi-bend thin-walled part with a reinforcement groove structure as claimed in claim 4, characterized in that: The tire mold I comprises a tire body (1), a cover plate (2), a positioning pin (3), a mold pin (4), a movable handle (5), and a hanging ring (6); the tire mold II comprises a tire body (7), a positioning pin (8), a mold pin (9), a cover plate (10), a side cover plate (12), a movable handle (12), and a hanging ring (13); the tire body (1) of the tire mold I is made into a "concave" structure, and the cover plate (2) is made into a "convex" structure.

Images