A device and method for forming the R zone of a large aircraft spring end

Abstract

The present invention belongs to the field of mechanical manufacturing. It is a device and a method for forming the R zone of a large spring end of an aircraft. It solves the problem that there is no special forming process equipment for the R zone of the large spring end, as well as insufficient process experience and technical parameters. The device is composed of three sets of tooling, which respectively correspond to the forming devices used in the three phased processes of the R zone of the large spring end. Through the combined assembly of the three-part structure of the device, the R zone of the large spring end can achieve seamless connection during bending and forming, and the positioning and clamping of the large spring is simple and fast, which effectively shortens the pre-processing preparation time and reduces the labor intensity of workers. The positioning and clamping of the large spring end during the forming process can be accurately controlled, so that the bending direction of the R zone of the spring end can be controlled during the forming process, the trajectory movement is accurate, and the dependence on the technical level of the operator is reduced. By realizing the efficient and high-quality forming of the R zone of the large spring end, the production efficiency is improved, the production cycle is shortened, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical manufacturing process equipment, and relates to a device for forming the R zone of a large aircraft spring end and a use method thereof. Background Art

[0002] Springs with a wire diameter greater than 12mm are generally called large springs, usually made of 50CrVA. Due to the excellent mechanical properties of the material, it is often used in the fields of aerospace, vehicles, ships, and engineering machinery. The connection between the rear fuselage and the weapon door of a certain type of aircraft of our company uses a group of large spring structures as the opening and closing device of the door. In order to meet the subsequent production needs of multiple models and master the overall manufacturing process of large springs, it is necessary to carry out independent research and development and production of large springs.

[0003] Through understanding the manufacturing process of existing large spring components, it is found that the number of special process equipment involved is very small, and the tools and tooling used in the large spring manufacturing process are mostly simple and homemade, relying on experience inheritance during use. The tools are severely worn and have been repaired many times, so it is impossible to extract effective information.

[0004] Therefore, it is necessary to explore and develop various process parameters and related process equipment in the manufacturing process of large springs. Summary of the invention

[0005] The present invention provides a set of brand-new process equipment, constructs a device for forming the R zone of the end of a large spring part of an aircraft, and provides a method for using the device. The present invention solves the problems of no special tooling, incomplete process method parameters, and insufficient technical means in the development process of the R zone of the end of a large spring, designs a discrete structure tooling, decomposes the forming process of the R zone of the end of a large spring into three processes, and uses a segmented R zone forming die to realize the forming control of the R zone of the end of a large spring, so that the R zone of the end of the large spring is accurately positioned during bending, effectively reducing the dependence on the technical level of the operator, and at the same time, the positioning and clamping operation of the large spring is simple, reducing the labor intensity of workers, shortening the manufacturing cycle, and reducing production costs.

[0006] Technical Solution

[0007] A device for forming the R zone of a large spring end of an aircraft, the device is composed of three sets of tooling, which respectively correspond to the forming devices used in the R zone of the large spring end in three phased processes. It is composed of a universal basic module, an R zone forming die, and a spring clamping module. The universal basic module is composed of a guide column 1, a bushing 2, a positioning pin 3, a hexagon socket screw 4, a base 5, and a welding handle 6. The lower die of the R zone forming mold is installed on one side of the base 5 and fixed with pins and screws; the spring clamping die positions and clamps the end of the large spring 7, and fixes it on the base 5 through pins and screws; the R zone forming molds of the three sets of tooling respectively include the first R zone forming mold upper die A1, the first R zone forming mold lower die A2, the second R zone forming mold upper die B1, the second R zone forming mold lower die B2, the third R zone forming mold upper die C1, and the third R zone forming mold lower die C2; ​​the tops of the R zone forming mold lower die A1, the R zone forming mold lower die B1, and the R zone forming mold lower die C1 are respectively provided with guide columns 1 that are matched and connected with the R zone forming mold upper die A2, the R zone forming mold upper die B2, and the R zone forming mold upper die C2, and the outer side of the guide column 1 is provided with a bushing 2;

[0008] The first R zone forming mold lower die A2, the second R zone forming mold lower die B2, and the third R zone forming mold lower die C2 are all provided with spring R zone forming modules; the first R zone forming mold lower die A2 has a first semicircular structure A in a vertical direction, the second R zone forming mold lower die B2 is provided with a second semicircular structure B in a horizontal direction, and the third R zone forming mold lower die C2 is provided with a third groove matching the spring end R zone; the spring clamping modules of the three sets of tooling respectively include spring clamping mold a, spring clamping mold b, and spring clamping mold Clamping die c; spring clamping die a comprises a spring clamping die upper die a1 and a spring clamping die lower die a2; the spring clamping die upper die a1 and the spring clamping die lower die a2 are fixed by screws and latches; the structures and fixing methods of spring clamping die b and spring clamping die c are the same as those of spring clamping die a; the working surface cavity of spring clamping die b in contact with the spring is obtained by rotating the working surface cavity of spring clamping die a 90° clockwise, and the working surface cavity of spring clamping die c in contact with the spring is obtained by rotating the working surface cavity of spring clamping die b 90° clockwise;

[0009] Preferably, a spring end avoidance area A is provided on the upper die A1 of the first R zone forming die, and a spring end avoidance area B is provided on the upper die B1 of the second R zone forming die;

[0010] Preferably, the lower die A2 of the first R zone forming die further includes a boss, the boss is integrated with the first semicircular structure A, one side of the boss has the same arc as the semicircular structure, and the other side is a plane structure; the height of the boss should be greater than the radius of the first semicircular structure A;

[0011] Preferably, the second semicircular structure B on the lower mold B2 of the second R zone forming mold is integrally formed;

[0012] The second semicircular structure B is obtained by rotating the working surface of the first semicircular structure A clockwise by 90°.

[0013] The base 5 is provided with a weight-reducing groove; the base 5 is provided with a welding handle 6 in the length direction;

[0014] The materials of the first R-zone forming die upper die A1, the first R-zone forming die lower die A2, the second R-zone forming die upper die B1, the second R-zone forming die lower die B2, the third R-zone forming die upper die C1, and the third R-zone forming die lower die C2 are metal materials with high tensile strength and hardness;

[0015] Preferably, the materials of the first R zone forming die upper die A1, the first R zone forming die lower die A2, the second R zone forming die upper die B1, the second R zone forming die lower die B2, the third R zone forming die upper die C1, and the third R zone forming die lower die C2 are selected from CrWMn;

[0016] A method for forming the R zone of a large aircraft spring end, comprising the following steps:

[0017] Step 1. Fix the lower die A2 of the first R-zone forming die used for the first bending process on the base 5 through the positioning pins 3 and the hexagon socket screws 4;

[0018] Step 2. The spring body part of the large spring near the end R area is positioned and clamped in the working surface cavity of the upper die a1 and the lower die a2 of the spring clamping die, and then the upper die a1 and the lower die a2 of the spring clamping die are fixed by quick release pins, studs, and shoulder nuts;

[0019] Step 3. The worker first bends the large spring end at a small angle to the spring end avoidance area A of the upper die A1 of the first R zone forming die;

[0020] Step 4. After the upper die A1 of the first R-zone forming die is connected with the lower die A2 of the first R-zone forming die through the guide column 1 and the bushing 2, the whole tooling is fixed on the working platform of the press, and the press shaft head acts on the upper die A1 of the first R-zone forming die. Following the axial movement of the guide column 1, the end of the large spring is bent along the groove track on the first semicircular structure A, and the first bending process is completed after reaching the predetermined bending angle;

[0021] Step 5. Remove the first R zone forming die upper die A1, the first R zone forming die lower die A2, the spring clamping die upper die a1, and the spring clamping die lower die a2, and separate them from the base 5 on the universal basic module;

[0022] Step 6. Install the second R-zone forming die upper die, the second R-zone forming die lower die and the second spring clamping die for the second bending process, and repeat steps 1 to 5;

[0023] Step 7. Install the third R zone forming die upper die, the third R zone forming die lower die and the third spring clamping die for the third bending process, and repeat steps 1 to 5;

[0024] Step 8. After the three bending processes are completed, take out the large spring, inspect the bending effect and quality of the R area at the end, and make corrections according to the actual situation;

[0025] Step 9. After the three sets of tooling are removed, they are packaged and classified, and kept sealed for next use. At this point, the entire set of operating procedures for forming the R zone of the large spring end is completed.

[0026] Technical Effects

[0027] The present invention solves the problem of lack of spring end R zone forming tooling and existing process experience and technical parameters, provides a new set of process equipment, and designs a reconfigurable tooling system with three processes in the spring end R zone forming stage. Through the combined assembly of the three-part structure of the device, the large spring end R zone is seamlessly connected during the forming process, making the positioning and clamping of the large spring simple and fast, shortening the processing preparation time, and reducing the labor intensity of workers.

[0028] The device can meet the process requirements of the large spring development process, provide auxiliary process equipment for the large spring end when forming the R zone, and reduce the risk of human operation during the R zone forming process of the large spring end. The device has been verified by the workshop and has obvious effects, meeting the design and manufacturing requirements of large springs.

[0029] The present invention can accurately control the positioning and clamping of the R zone of the large spring end during the forming process, so that the bending direction of the R zone of the large spring end can be controlled and the trajectory movement is accurate during the forming process, which reduces the dependence on the operator's technical level. The positioning and clamping operation of the tooling is simple, which effectively reduces the later shape correction work of the R zone of the large spring end, improves production efficiency, and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the R zone forming of the large spring end;

[0031] Where: M. Initial shape of the end; N. Shape of the end after the first bending; P. Shape of the end after the second bending; Q. Shape of the end after the third bending;

[0032] Figure 2a This is a schematic diagram of the tooling structure for the first bending of the R area at the end of the large spring;

[0033] Among them: 1. Guide column; 2. Bushing; 3. Positioning pin; 4. Hexagon socket screw; 5. Base; 6. Welding handle; 7. Large spring; a1. Upper die of spring clamping die; a2. Lower die of spring clamping die;

[0034] Figure 2b This is a schematic diagram of the tooling structure for the second bending of the R area at the end of the large spring;

[0035] Among them: 7. Large spring;

[0036] Figure 2c This is a schematic diagram of the tooling structure for the third bending of the R area at the end of the large spring;

[0037] Among them: 7. Large spring;

[0038] Figure 3 This is a schematic diagram of the forming die structure of the R zone of the first bending tooling;

[0039] Wherein: A1. Upper die of R zone forming die; A2. Lower die of R zone forming die; A. Semicircular structure;

[0040] Figure 4 This is a schematic diagram of the structure of the clamping die a of the first bending tool spring;

[0041] Wherein: a1. upper die of spring clamping die; a2. lower die of spring clamping die; 5. base;

[0042] Figure 5 It is a schematic diagram of the forming die structure of the R zone of the second bending tooling;

[0043] Wherein: B1. Upper die of R zone forming die; B2. Lower die of R zone forming die; B. Semicircular structure;

[0044] Figure 6 This is a schematic diagram of the structure of the clamping die b of the second bending tool spring;

[0045] Wherein: b1. upper die of spring clamping die; b2. lower die of spring clamping die; 5. base;

[0046] Figure 7 This is a schematic diagram of the third bending tooling structure;

[0047] Wherein: C1. Upper die of R zone forming die; C2. Lower die of R zone forming die;

[0048] Figure 8 This is a schematic diagram of the structure of the clamping die c of the third bending tool spring;

[0049] Wherein: c1. upper die of spring clamping die; c2. lower die of spring clamping die; 5. base;

[0050] Fig. 9 The figure is a flow chart of the method for using the present invention. DETAILED DESCRIPTION

[0051] The common basic module of the three sets of tooling realizes the quick connection and interchange of the R zone forming die and the spring clamping die on each set of tooling. It is beneficial to control the total manufacturing cost of the tooling and also reduces the changeover time between adjacent processes when the R zone of the large spring end is formed. The R zone forming die corresponds to the three processing steps of the large spring end when forming the R zone, and each process uses a set of forming dies. The spring clamping die is used to position and clamp the spring in each processing step of the large spring.

[0052] The universal basic module is mainly composed of a guide column (1), a bushing (2), a positioning pin (3), a hexagon socket screw (4), and a base (5). Among them: the base (5) is used as a common working platform for the three sets of tooling. It uses 45 steel with high strength and wear resistance. The flatness and parallelism of its upper and lower surfaces both reach 0.1, and the roughness is 1.6. Pin holes and bolt holes are reserved on the base (5) according to the structure of the R-zone forming mold and the spring clamping mold of the three sets of tooling. The R-zone forming mold is fixed to the base (5) by the positioning pin (3) and the hexagon socket screw (4), and the spring clamping mold is fixed to the base (5) by screws and short pins. This not only ensures the overall strength of the tooling, but also facilitates the subsequent repair and structural expansion optimization of the R-zone forming mold and the spring clamping mold.

[0053] The R-zone forming dies are respectively composed of R-zone forming die group components corresponding to three different processes, including the first bending tooling R-zone forming die upper die (A1), R-zone forming die lower die (A2), the second bending tooling R-zone forming die upper die (B1), R-zone forming die lower die (B2), and the third bending tooling R-zone forming die upper die (C1), R-zone forming die lower die (C2). Each pair of R-zone forming dies is used in conjunction with a press device. After the welding handle (6) is positioned and clamped, the end is fixed in the semicircular structure and spring clamping die of the R-zone forming die. Under the action of pressure, plastic deformation occurs along the groove track on the semicircular structure to form a theoretical bending angle. Since the material of the large spring is 50CrVA, which has strong tensile strength and hardness, CrWMn with higher tensile strength and hardness than 50CrVA is selected as the mold material for bearing pressure transmission when designing the R zone forming mold. At the same time, in order to reduce the surface indentation and scratches after the end R zone is bent, the surface of the groove on the semicircular structure of the mold also has a higher surface roughness. The upper and lower molds of the R zone forming mold are connected by guide pins (1) and bushings (2) when they are matched, which effectively ensures that the pressure of the press is transmitted in the axial direction, reduces the deviation of the angle of the large spring end R zone after bending, and reduces the workload during correction.

[0054] The spring clamping die is composed of spring clamping die group components corresponding to three different processes, including the upper die (a1) and the lower die (a2) of the spring clamping die for the first bending of the large spring, the upper die (b1) and the lower die (b2) of the spring clamping die for the second bending, and the upper die (c1) and the lower die (c2) of the spring clamping die for the third bending. Each pair of spring clamping dies is used in groups, corresponding to the winding state of the spring body in the previous process of the bending of the R zone of the large spring end. Before the bending process, the R zone of the large spring end is positioned and clamped by the working surface cavity in the upper and lower dies of the spring clamping die. The upper and lower dies after alignment are fixed by studs and shoulder nuts to ensure that the spring body of the large spring does not move axially or rotate radially during the bending process of the R zone of the large spring end under the action of the press, and at the same time reduce the impact of the spring body rebound. At the same time, in order to solve the impact of slightly different pitches of the same batch of large springs after winding on the CNC spring winding machine, the connecting holes between the upper and lower dies of the spring clamping die are set as waist-shaped holes, so that the upper die of the spring clamping die has a certain adjustment margin to eliminate the positioning and clamping problems caused by the spring pitch tolerance range.

[0055] The present invention is described in detail with reference to the accompanying drawings:

[0056] A device for forming the R zone of a large spring end of an aircraft is provided, characterized in that the device is composed of three sets of tooling, which respectively correspond to the forming devices used in the R zone of the large spring end in three staged processes. It is composed of a universal basic module, an R zone forming die, and a spring clamping die. The universal basic module is composed of a guide column 1, a bushing 2, a positioning pin 3, a hexagon socket screw 4, and a base 5. It can be used as a universal basic module for three sets of tooling, and realizes the rapid connection and interchangeability of the R zone forming die and the spring clamping die on each set of tooling, which is conducive to controlling the total cost of tooling manufacturing and reducing the replacement time between adjacent processes when manufacturing the R zone of the large spring end. The R zone forming die corresponds to the three processing steps of the large spring end when forming the R zone, and each process uses a set of R zone forming dies to ensure the connectivity during the forming transition. The spring clamping die is used to position and clamp the spring during the forming process of the R zone of the large spring end.

[0057] When the device is used, the lower die (A2) of the R zone forming die used in the first bending process is fixed to the base (5) by means of positioning pins (3) and hexagon socket screws (4), and the spring body portion of the large spring close to the end R zone is positioned and clamped in the working surface cavity of the upper die (a1) and the lower die (a2) of the spring clamping die. Then, the upper die (a1) and the lower die (a2) of the spring clamping die are fixed by means of quick release pins, studs and shoulder nuts. After completion, the worker first performs an initial small-angle bend on the end of the large spring to the spring end avoidance zone of the upper die (A1) of the R zone forming die. Subsequently, the upper die (A1) of the R zone forming die and the lower die (A2) of the R zone forming die are fixed by means of guide pins (1) and bushings (2). After the entire tooling is fixed on the working platform of the press, the press shaft head acts on the upper die (A1) of the R-zone forming die, and the pressure is transmitted to the first semicircular structure A on the lower die (A2) of the R-zone forming die along the axial movement of the guide column (1). The end of the large spring is bent along the groove track on the first semicircular structure A, and the first bending process is completed after reaching the bending angle. Then remove the upper die (A1) of the R-zone forming die, the lower die (A2) of the R-zone forming die, the upper die (a1) of the spring clamping die, and the lower die (a2) of the spring clamping die, separate them from the base (5) on the universal base block, install the tooling R-zone forming die and spring clamping die for the second bending process, and repeat the previous operation process. After completion, follow the same steps to complete the connection of the tooling R-zone forming die and the spring clamping die for the third bending process, as well as the bending process under the press.

[0058] After the three bending processes are completed, the R-zone forming die and spring clamping die of the third process are removed. After the large spring is taken out, the bending effect and quality of the R area of ​​the end are inspected and adjusted according to the actual situation. After the three sets of tools are removed, they are classified and packaged, and kept sealed for the next use. The whole set of operation procedures for forming the R area of ​​the large spring end is completed.

[0059] The spring clamping mold (a1) is a rectangular block; preferably, the two sides of the spring clamping mold (a1) are provided with rectangular sunken grooves for easy handholding;

[0060] The spring clamping die (a2) is an L-shaped block; preferably, the spring clamping die (a2) is provided with a dodging groove for screws and quick-release latches;

[0061] The spring clamping mold (c1) is a rectangular block; preferably, rectangular sunken grooves are provided on both side surfaces of the spring clamping mold (c1) for easy handholding; and a rectangular groove is provided on the upper surface;

[0062] The spring clamping mold (c2) is a rectangular block; preferably, the spring clamping mold (c2) is provided with a dodging groove for screws and quick-release latches;

[0063] The boss of the lower die (A2) of the R zone forming die is in contact with the groove on the first semicircular structure A that fits with the end of the large spring.

[0064] The groove on the boss of the lower die (B2) of the R zone forming die that fits with the end of the large spring has a groove roughness of not less than 0.8 and a contour of not more than 0.1.

Claims

1. A device for forming the R zone of a large aircraft spring end, characterized in that: The device is composed of three sets of tooling, which respectively correspond to the forming devices used in the R zone of the end of the large spring in three staged processes; it is composed of a universal basic module, an R zone forming die, and a spring clamping module; the universal basic module is composed of a guide column (1), a bushing (2), a positioning pin (3), a hexagon socket screw (4), a base (5), and a welding handle (6); the lower die of the R zone forming die is installed on one side of the base (5) and fixed by pins and screws; the spring clamping die positions and clamps the end of the large spring (7) and fixes it to the base (5) by pins and screws; the R zone forming die of the three sets of tooling respectively includes the first An upper mold (A1) of an R zone forming mold, a lower mold (A2) of a first R zone forming mold, an upper mold (B1) of a second R zone forming mold, a lower mold (B2) of a second R zone forming mold, an upper mold (C1) of a third R zone forming mold, and a lower mold (C2) of a third R zone forming mold; the top ends of the lower mold (A2) of the first R zone forming mold, the lower mold (B2) of the second R zone forming mold, and the lower mold (C2) of the third R zone forming mold are respectively provided with guide pillars (1) matched and connected with the upper mold (A1) of the first R zone forming mold, the upper mold (B1) of the second R zone forming mold, and the upper mold (C1) of the third R zone forming mold, and the outer sides of the guide pillars (1) are provided with bushings (2); The first R zone forming mold lower mold (A2), the second R zone forming mold lower mold (B2), and the third R zone forming mold lower mold (C2) are all provided with spring R zone forming modules; the first R zone forming mold lower mold (A2) has a vertical first semicircular structure (A), the second R zone forming mold lower mold (B2) is provided with a horizontal second semicircular structure (B), and the third R zone forming mold lower mold (C2) is provided with a third groove matching the spring end R zone; the spring clamping modules of the three sets of tooling respectively include a first spring clamping mold (a), a second spring clamping mold (b), and a third spring clamping mold (c); the first spring clamping mold (a) comprises a spring clamping die upper die (a1) and a spring clamping die lower die (a2); the spring clamping die upper die (a1) and the spring clamping die lower die (a2) are fixed by screws and latches; the second spring clamping die (b) and the third spring clamping die (c) have the same structure and fixing method as the first spring clamping die (a); the working surface cavity of the second spring clamping die (b) in contact with the spring is obtained by rotating the working surface cavity of the first spring clamping die (a) 90° clockwise, and the working surface cavity of the third spring clamping die (c) in contact with the spring is obtained by rotating the working surface cavity of the second spring clamping die (b) 90° clockwise.

2. A device for forming the R zone of a large aircraft spring end according to claim 1, characterized in that: A spring end avoidance area A is provided on the upper die (A1) of the first R zone forming die, and a spring end avoidance area B is provided on the upper die (B1) of the second R zone forming die.

3. The device for forming the R zone of a large aircraft spring end according to claim 1, characterized in that: The first R zone forming mold lower mold (A2) also includes a boss, which is integrated with the first semicircular structure (A), and the surface of one side of the boss has the same arc as the first semicircular structure (A), and the other side is a flat structure; the height of the boss should be greater than the radius of the first semicircular structure (A); the second semicircular structure (B) on the second R zone forming mold lower mold (B2) is integrally formed.

4. The device for forming the R zone of the end of a large aircraft spring according to claim 3, characterized in that: The second semicircular structure (B) is obtained by rotating the working surface of the first semicircular structure (A) clockwise by 90°.

5. The device for forming the R zone of the end of a large aircraft spring according to claim 1, characterized in that: The base body (5) is provided with a weight-reducing groove; and the base body (5) is provided with a welding handle (6) in the length direction.

6. The device for forming the R zone of a large aircraft spring end according to claim 1, characterized in that: The materials of the first R zone forming mold upper mold (A1), the first R zone forming mold lower mold (A2), the second R zone forming mold upper mold (B1), the second R zone forming mold lower mold (B2), the third R zone forming mold upper mold (C1), and the third R zone forming mold lower mold (C2) are metal materials with high tensile strength and hardness.

7. The device for forming the R zone of the end of a large aircraft spring according to claim 6, characterized in that: The materials used for the first R zone forming mold upper mold (A1), the first R zone forming mold lower mold (A2), the second R zone forming mold upper mold (B1), the second R zone forming mold lower mold (B2), the third R zone forming mold upper mold (C1), and the third R zone forming mold lower mold (C2) are CrWMn.

8. A method for using the device according to any one of claims 1 to 7, characterized in that: The steps include: Step 1. Fix the lower die (A2) of the first R-zone forming die used for the first bending process on the base (5) through the positioning pin (3) and the hexagon socket screw (4); Step 2. The spring body part of the large spring near the end R area is positioned and clamped in the working surface cavity of the spring clamping die upper die (a1) and the spring clamping die lower die (a2), and then the spring clamping die upper die (a1) and the spring clamping die lower die (a2) are fixed by quick release pins, studs, and shoulder nuts; Step 3. The worker first performs a small-angle bend on the end of the large spring to the spring end avoidance area A of the upper die (A1) of the first R-zone forming die; Step 4. After the upper die (A1) of the first R-zone forming die is connected to the lower die (A2) of the first R-zone forming die through the guide column (1) and the bushing (2), the entire tooling is fixed on the working platform of the press, and the press shaft head acts on the upper die (A1) of the first R-zone forming die, and moves along the axial direction of the guide column (1), and the end of the large spring is bent along the groove track on the first semicircular structure (A), and the first bending process is completed after reaching the predetermined bending angle; Step 5. Remove the upper mold (A1) of the first R zone forming mold, the lower mold (A2) of the first R zone forming mold, the upper mold (a1) of the spring clamping mold, and the lower mold (a2) of the spring clamping mold, and separate them from the base (5) on the universal basic module; Step 6. Install the second R-zone forming die upper die, the second R-zone forming die lower die and the second spring clamping die for the second bending process, and repeat steps 1 to 5; Step 7. Install the third R zone forming die upper die, the third R zone forming die lower die and the third spring clamping die for the third bending process, and repeat steps 1 to 5; Step 8. After the three bending processes are completed, take out the large spring, inspect the bending effect and quality of the R area at the end, and make corrections according to the actual situation; Step 9. After the three sets of tooling are removed, they are packaged and classified, and kept sealed for next use. At this point, the entire set of operating procedures for forming the R zone of the large spring end is completed.

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