Hollow hook bending die and bending method thereof

Abstract

The application discloses a hollow hook bending die and a bending method thereof, which comprises an upper die part and a lower die part. The upper die part comprises an upper die seat, an upper backing plate fixedly connected to the bottom of the upper die seat, a material returning plate fixedly connected to the bottom end of the upper backing plate, a material returning plate insert fixedly connected to the bottom end of the material returning plate, a knife inserted into the upper die seat fixedly connected to the both sides of the upper backing plate, a lower pressing bending block fixedly connected to the bottom end of the material returning plate insert, and a movable lower pressing block obliquely and slidably connected to one side of the lower pressing bending block. The die structure of the application can realize 90-degree bending and 105-degree or more side bending in one process, reduces the number of dies and working steps, avoids errors caused by multiple processes, reduces the manufacturing and processing cost of the die, and realizes the overall bending of the automobile exhaust pipe head hollow hook with more than 105-degree symmetry in one process with one die structure.

Description

Technical Field

[0001] This invention relates to the field of cold stamping die technology, specifically to the structure of a cold stamping hollow hook bending die and its bending method. Background Technology

[0002] A beveling is a process that applies pressure to the end of a metal material, causing localized deformation to create a protrusion or thickened section, thereby increasing the strength of that area or meeting specific connection requirements. Bending, on the other hand, uses molds or mechanical devices to bend metal materials into desired angles or shapes. The hooks on car exhaust pipes utilize a method such as... Figure 5 The hollow tube with a raised head is then bent in the middle to form a symmetrical shape greater than 105 degrees, as shown. Figure 6 As shown, after bending, the hook needs to retain a relatively rounded hollow shape at the bend. The hollow hook head also needs to form a symmetrical bend greater than 105 degrees to meet the requirements for part assembly and use. Currently, this usually requires multiple processes, such as first using one set of molds to bend at 90°, and then using other molds or multiple processes for side bending to achieve a symmetrical angle greater than 105°. This method is cumbersome or the mold structure is complex, leading to low production efficiency, high cost, or affecting processing quality. Therefore, there is an urgent need for a simplified mold structure and processing method to achieve a symmetrical bend greater than 105 degrees for the hollow hook head of automotive exhaust pipes, thus solving the above problems. Summary of the Invention

[0003] To solve the problems mentioned in the background art above, the technical solution adopted by the present invention is: a hollow hook bending die, which includes an upper die part and a lower die part. The upper die part includes an upper die base, an upper pad plate fixedly connected to the bottom of the upper die base, a stripper plate fixedly connected to the bottom end of the upper pad plate, a stripper plate insert fixedly connected to the bottom end of the stripper plate, inserts symmetrically fixedly connected to both sides of the upper pad plate at the bottom end of the upper die base, a lower pressing bending block fixedly connected to the bottom end of the stripper plate insert, and a movable lower pressing block that is inclined and slidably connected to one side of the lower pressing bending block.

[0004] The lower mold portion includes a longitudinal bending component and a lateral bending component;

[0005] The longitudinal bending assembly includes a lower mold base, a longitudinal nitrogen spring fixedly connected to the top of the lower mold base, a float plate connected to the top of the longitudinal nitrogen spring, rotating pins symmetrically arranged on both sides of the upper end of the float plate, and a bending block body symmetrically and movably connected on both sides of the upper end of the float plate through the rotating pins.

[0006] The lateral bending assembly includes side push plates symmetrically arranged on both sides of the floating material plate at the upper end of the lower die base, sliders fixedly connected to both sides of the lower die base via the side push plates, and a template fixedly connected to the top of the slider with screws on the side of the inserter. The upper and lower die parts work together to first bend the workpiece to 90° by pressing down with the lower bending block and the movable lower pressing block in conjunction with the longitudinal bending assembly, and then bend it to greater than 105° by pushing the lateral bending assembly from the inside of the inserter.

[0007] As a preferred embodiment of the present invention, the front of the structure composed of the downward bending block and the movable downward pressing block is an isosceles trapezoid, and both sides of the bottom end of the isosceles trapezoid are provided with rounded chamfers.

[0008] As a preferred embodiment of the present invention, the side push plate is inclined at the end facing the lower pressing bending block and the movable lower pressing block, and the contact surface between the slider and the insert knife is a matching inclined surface structure.

[0009] As a preferred embodiment of the present invention, a guide rod is slidably sleeved on the side of the lower mold base near the longitudinal nitrogen spring, and the top end of the guide rod is fixedly connected to the bottom of the floating material plate. Two guide rods are provided.

[0010] As a preferred embodiment of the present invention, the top of the lower mold base is fixedly connected to guide blocks on both sides of the slider. The guide blocks are inverted L-shaped structures, and the slider is horizontally fitted and slidably connected between the two guide blocks.

[0011] As a preferred embodiment of the present invention, a stroke insert is fixedly connected to one side of the bottom end of the slider, and the stroke insert abuts against the telescopic end of the transverse nitrogen spring.

[0012] As a preferred embodiment of the present invention, the tail of the transverse nitrogen spring is disposed on the nitrogen spring pad, and an inner groove is provided on the upper end of the lower mold base facing the transverse nitrogen spring. The transverse nitrogen spring and the nitrogen spring pad are both disposed inside the inner groove.

[0013] As a preferred embodiment of the present invention, the floating material plate is provided with a workpiece placement groove, and the floating material plate is used to horizontally place the pier head pipe fitting through the workpiece placement groove.

[0014] A method for bending a hollow hook based on the above-mentioned mold structure includes the following steps:

[0015] S1. Drive the upper mold part to the upper stop point, the mold opens, the longitudinal nitrogen spring (19) lifts the floating plate (8) to the highest position, the transverse nitrogen spring (16) pushes the slider (14) to the initial position, and the pier head pipe fitting (21) is horizontally placed into the workpiece placement groove of the floating plate (8) to complete the positioning.

[0016] S2, drive the upper mold part to move down, the movable lower pressure block (6) contacts the pier head pipe fitting (21) and slides down along the inclined surface of the lower pressure bending block (7) and closes to form a combined mold, the ejector plate (3) presses the pier head pipe fitting (21) and pushes the floating plate (8) to overcome the lifting force of the longitudinal nitrogen spring (19) and move down, the bending block body (10) rotates inward around the rotating pin (9) so that the pier head pipe fitting (21) is bent into 90°;

[0017] S3. The upper mold continues to move downwards. The insert (5) fits against the template (12) on the slider (14) through the inclined surface, converting the vertical pressure into a horizontal thrust. This pushes the slider (14) to overcome the force of the horizontal nitrogen spring (16) and slide horizontally inwards along the guide block (15). The slider (14) drives the side push plate (11) to push the 90° bent end pipe (21) inwards. After the end pipe (21) is bent into a symmetrical structure greater than 105°, the upper mold stops moving downwards.

[0018] S4. Move the upper mold part upward, the insert (5) separates from the slider (14), the horizontal nitrogen spring (16) pushes the slider (14) to return to horizontal reset, the upper mold part continues to move upward, the ejector plate (3) separates from the head pipe fitting (21), the vertical nitrogen spring (19) lifts the floating plate (8) to return to reset, and pushes the formed head pipe fitting (21) out of the working area.

[0019] Finally, the upper mold moves to the upper stop point, the mold opens completely, and the formed cold-stamped hollow hook is taken out, completing the single bending process.

[0020] The present invention has the following advantages:

[0021] Using the mold structure of this invention, a single mold can simultaneously achieve multi-dimensional bending, workpiece positioning and clamping, automatic reset and unloading, and precision anti-deviation structure functions. It can complete the 90° longitudinal bending and >105° symmetrical lateral bending of the hollow hook of the automobile exhaust pipe head in one process, reducing the number of molds and steps, avoiding errors caused by multiple processes, reducing mold manufacturing and processing costs, and improving the bending quality of the hollow hook. Moreover, its mold movement is stable, and the overall bending processing of the hollow hook of the automobile exhaust pipe head with symmetry greater than 105 degrees can be achieved in one mold structure. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the mold closing structure according to a preferred embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the mold parting structure according to a preferred embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the exploded structure of the lower mold portion according to a preferred embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the exploded structure of the upper mold portion according to a preferred embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the unbent structure of the pipe fitting in a preferred embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of the bending structure of the pipe fitting in a preferred embodiment of the present invention.

[0028] Explanation of reference numerals in the attached drawings: 1. Upper mold base; 2. Upper backing plate; 3. Ejector plate; 4. Ejector plate insert; 5. Insert knife; 6. Movable lower pressure block; 7. Lower pressure bending block; 8. Floating plate; 9. Rotating pin; 10. Bending block body; 11. Side push plate; 12. Durable template; 13. Nitrogen spring pad; 14. Slider; 15. Guide block; 16. Transverse nitrogen spring; 17. Stroke insert; 1701. Inner groove; 18. Lower mold base; 19. Longitudinal nitrogen spring; 20. Guide rod; 21. Head fitting. Detailed Implementation

[0029] The technical solution of the present invention will now be clearly and completely described in conjunction with the accompanying drawings. In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] The invention will now be further described with reference to the accompanying drawings.

[0032] Example 1

[0033] Please refer to the following: Figures 1-4A hollow hook bending die includes an upper die part and a lower die part. The upper die part includes an upper die base 1, an upper pad 2 fixedly connected to the bottom of the upper die base 1, a stripper plate 3 fixedly connected to the bottom end of the upper pad 2, a stripper plate insert 4 fixedly connected to the bottom end of the stripper plate 3, inserts 5 symmetrically fixedly connected to both sides of the upper pad 2 at the bottom end of the upper die base 1, a lower pressing bending block 7 fixedly connected to the bottom end of the stripper plate insert 4, and a movable lower pressing block 6 inclined and slidably connected to one side of the lower pressing bending block 7.

[0034] The lower mold section includes a longitudinal bending component and a lateral bending component;

[0035] The longitudinal bending assembly includes a lower mold base 18, a longitudinal nitrogen spring 19 fixedly connected to the top of the lower mold base 18, a float plate 8 connected to the top of the longitudinal nitrogen spring 19, rotating pins 9 symmetrically arranged on both sides of the upper end of the float plate 8, and a bending block body 10 symmetrically and movably connected on both sides of the upper end of the float plate 8 through the rotating pins 9.

[0036] The lateral bending assembly includes side push plates 11 symmetrically arranged on both sides of the floating material plate 8 at the upper end of the lower die base 18, sliders 14 fixedly connected to both sides of the lower die base 18 via the side push plates 11, and a wear-resistant template 12 fixedly connected to the top of the sliders 14 with screws on one side facing the insert 5. The die is driven by the movement of the punch press slider to achieve the bending action of the workpiece. The upper and lower die parts work together. First, the lower bending block 7 and the movable lower pressing block 6 press down in conjunction with the longitudinal bending assembly to bend the workpiece to 90°. Then, the insert 5 pushes the lateral bending assembly from the inside to bend it to greater than 105°. The wear-resistant template 12 can enhance the wear resistance and stability of the lower die.

[0037] The structure consisting of the lower bending block 7 and the movable lower pressing block 6 has an isosceles trapezoidal shape on the front, and both sides of the bottom of the isosceles trapezoid are provided with rounded chamfers. The side push plate 11 is inclined at the end facing the lower bending block 7 and the movable lower pressing block 6. The contact surface between the slider 14 and the insert 5 is a matching inclined surface structure. The lower mold base 18 is slidably sleeved with a guide rod 20 on the side near the longitudinal nitrogen spring 19. The top of the guide rod 20 is fixedly connected to the bottom of the floating material plate 8.

[0038] Two guide rods 20 are provided to ensure the stability of the floating plate 8's vertical movement. Guide blocks 15, which are inverted L-shaped structures, are fixedly connected to the top of the lower mold base 18 on both sides of the slider 14. The slider 14 is horizontally slidably connected between the two guide blocks 15. A stroke insert 17 is fixedly connected to one side of the bottom of the slider 14, and the stroke insert 17 abuts against the telescopic end of the transverse nitrogen spring 16. The tail of the transverse nitrogen spring 16 is located on a nitrogen spring pad 13. An inner groove 1701 is formed on the upper end of the lower mold base 18, directly opposite the transverse nitrogen spring 16. The transverse nitrogen spring 16 and the nitrogen spring pad 13 are both located inside the inner groove 1701. The floating plate 8 has a workpiece placement slot, through which the pierced pipe fitting 21 is horizontally placed. The guide blocks 15 and the stroke insert 17 cooperate to ensure the precise movement trajectory of the slider 14 and consistent bending angles.

[0039] Specifically, in this invention, when the punch press is in the open mold state at the upper stop point, the hollow uphead tube 21 is placed on the floating plate 8 of the lower mold part of the bending die. The upper mold part of the punch press moves down, driving the upper mold part to move down together. Then, the movable lower pressing block 6 at the bottom of the upper mold part contacts the uphead tube 21 and pushes it upward, combining with the lower pressing bending block 7 to form a combined mold. Then, the uphead tube 21 is pressed by the ejector plate 4 and then moves downward to contact the side push plate 11 and then moves downward, so that the uphead tube 21 is bent to 90°. Then, the inserter 5 contacts the slider 14 and moves laterally, so that the uphead tube 21 is pushed laterally and bent to 105° and then stops moving.

[0040] After the press completes the stamping process, the press begins to drive the upper die part to move upward. The upper die base 1 moves upward, the cutter 5 moves upward, and the slider 14 returns to its original position under the action of the internal transverse nitrogen spring 16. The upper die base 1 continues to move upward, and the float plate 8 is pushed upward by the longitudinal nitrogen spring 19 to push the end cap 21 away from the working area, so that the end cap 21 is carried upward and separated from the upper die part. It continues to move upward and returns to its original position. The press moves to the upper stop point and takes out the punched end cap 21, completing one stamping process.

[0041] The upper mold part and the lower mold longitudinal and lateral bending components are not independent, but integrated into an overall structure that can continuously complete multi-angle bending. A single structure can simultaneously bear bending of 90° and >105°.

[0042] The inclined structure of the insert 5 and the slider 14 allows the vertical movement of the insert as the upper mold moves downward to be directly converted into the horizontal thrust of the slider through the inclined contact. A single structure simultaneously realizes vertical power transmission, horizontal force conversion, and lateral bending thrust output without the need for an additional power conversion mechanism. At the same time, the inclined contact between the slider and the insert can also realize adaptive limit of the movement stroke, avoiding excessive thrust that would cause the workpiece bending angle to exceed the tolerance, thus realizing power conversion and precision control. The guide block 15 is inverted L-shaped: symmetrically fixed on both sides of the slider. Its structure that fits the slider not only restricts the slider to only make horizontal linear movements, realizing the movement guidance for lateral bending, but also prevents the slider from warping or deviating during movement through the inverted L-shaped limit structure, thus protecting the stability of the mold movement. At the same time, it provides a trajectory for the slider's reset movement, ensuring both bending accuracy and mold structural stability.

[0043] Two guide rods (20) are slidably connected between the lower mold base and the floating material plate. They provide vertical guidance for the up-and-down movement of the floating material plate, ensuring the horizontality of the floating material plate when it is lifted and ejected. They also limit the stroke of the floating material plate, preventing the workpiece from falling out of the positioning groove due to excessive longitudinal nitrogen spring lifting force. At the same time, they provide vertical support for the floating material plate when it is bent at 90°, preventing the floating material plate from being excessively deformed due to the pressure of the upper mold. They achieve guidance, stroke limitation and structural support.

[0044] Its elastic reset structure allows a single nitrogen spring assembly to achieve both reset and ejection of multiple components. The mold uses a dual nitrogen spring assembly with a transverse nitrogen spring 16 and a longitudinal nitrogen spring 19. Both assemblies are single structures that bear the reset of mold components and ejection of processed workpieces, eliminating the need for additional reset cylinders and manual ejection devices. This balances the automation level of the mold with its structural simplicity.

[0045] The positioning and clamping structure of this mold enables a single platform to perform multiple functions, including workpiece positioning, clamping, and bending support.

[0046] The float plate 8 of the lower die serves as the workpiece support platform of the die. Through a simple structure, a workpiece placement slot is provided. A single platform enables precise workpiece positioning, clamping during the bending process, and support of bending force, ensuring the symmetry and accuracy of the bending.

[0047] The workpiece placement groove of the floating material plate is designed according to the shape of the pipe fitting. It can accurately limit the workpiece to be processed, avoid horizontal displacement of the workpiece when the upper mold is pressed down, realize the precise positioning of the hollow hook symmetrical bending, and ensure the consistency of the bending angle on both sides.

[0048] During the 90° bending process, the upper die ejector plate 3 presses the workpiece on the floating plate. The floating plate, as a clamping support platform, works with the ejector plate to achieve vertical clamping of the workpiece, preventing warping and deformation of the workpiece during bending.

[0049] In the two bending processes, the floating plate always provides horizontal support for the workpiece, bearing the downward bending force of the upper die and the lateral pushing force, avoiding the hollow tube from denting or cracking due to uneven force, and at the same time providing stable workpiece support for the bending block body 10 and the side push plate 11 bending action, thus achieving support and preventing workpiece deformation.

[0050] This mold has a simple and practical overall structure, and it can fully realize the overall bending process of hollow hooks on automobile exhaust pipe heads with symmetry greater than 105 degrees in one process, one mold structure, and one stamping.

[0051] Example 2

[0052] A method for bending a cold-stamped hollow hook based on the above-mentioned mold structure, the specific steps of which are as follows:

[0053] S1. Material preparation

[0054] The punch press drives the upper die to its upper stop, and the die is in a fully open state. At this time, the longitudinal nitrogen spring 19 is in a naturally lifted state, pushing the float plate 8 to move up to its highest position along the two guide rods 20, so that the workpiece placement slot on the float plate 8 is fully exposed, facilitating workpiece placement. At the same time, the transverse nitrogen spring 16 is in a naturally extended state, pushing the slider 14 to move horizontally outward along the inverted L-shaped guide block 15 to its initial position through the stroke insert 17. The side push plate 11 maintains a reasonable distance from the float plate 8 without interference. The hollow upturned pipe fitting 21 to be processed is horizontally placed into the workpiece placement slot of the float plate 8. The outer shape limit of the workpiece placement slot is used to achieve precise circumferential and radial positioning of the upturned pipe fitting 21, ensuring the symmetry of subsequent bending from the source.

[0055] S2, 90° longitudinal bend

[0056] The punch press starts and drives the upper die to move downwards at a constant speed in the vertical direction. The movable lower pressure block 6 at the bottom of the upper die first contacts the middle of the tube head fitting 21. Under the supporting reaction force of the tube head fitting 21, the movable lower pressure block 6 slides upwards along the inclined surface of the lower pressure bending block 7 until it is completely closed with the lower pressure bending block 7, forming a combined die that matches the middle of the tube head fitting 21, thus avoiding stress concentration and depression in the middle of the tube body during bending. Subsequently, the ejector plate 3 of the upper die adheres to the upper surface of the tube head fitting 21 and vertically presses the workpiece, making the tube head fitting... The workpiece placement groove of the float plate 8 is completely fitted without any looseness; the ejector plate 3 continues to move downward with the upper die and pushes the float plate 8 to overcome the lifting force of the longitudinal nitrogen spring 19, sliding vertically downward along the guide rod 20. As the head pipe 21 moves downward with the float plate 8, its two ends contact the bending block body 10. The continuous downward pressure of the upper die is transmitted to the bending block body 10, causing it to rotate inward around the rotating pin 9 until the bending block body 10 and the float plate 8 form a 90° angle, and the head pipe 21 is precisely bent into a 90° right angle structure. During this process, the lower bending block 7 and the movable lower pressing block 6 always fit against the middle of the head pipe 21, providing forming contour support for bending and ensuring the roundness of the bent part of the hollow pipe.

[0057] S3, >105° lateral bend

[0058] After the 90° longitudinal bend is completed, the upper die continues to move downwards vertically without pause. The inserts 5 on both sides of the upper die base 1 move downwards accordingly, and their inclined surfaces precisely fit with the platen 12 at the top of the slider 14. The inclined surface adaptation structure efficiently converts the vertical downward pressure input from the punch press into a horizontal lateral thrust without the need for an additional power conversion mechanism. Under the action of this lateral thrust, the slider 14 overcomes the extension force of the lateral nitrogen spring 16 and slides horizontally inwards along the inverted L-shaped guide block 15 towards the floating plate 8. The guide block 15 restricts the slider 1 throughout its entire movement. 4. Only horizontal linear motion is performed to ensure the synchronicity of the movement and consistency of the stroke of the sliders 14 on both sides, and to ensure that the bending angles on both sides of the hook are symmetrical. While the sliders 14 slide horizontally inward, they drive the side push plates 11 to move inward synchronously. The side push plates 11 contact the two ends of the 90° bent end pipe fitting 21 and apply a continuous lateral thrust, so that the bending angle of the end pipe fitting 21 gradually increases from 90° until a bending structure with a **symmetry greater than 105°** is formed. At this time, the upper die part of the punch press stops moving downward, and the bending is completed.

[0059] S4, Mold Reset

[0060] After the punch press completes the stamping and forming, it reverses direction, causing the upper die to move upward at a constant speed in the vertical direction. The inserts 5 on both sides of the upper die move upward and gradually disengage from the template 12 on the slider 14. The lateral thrust applied to the slider 14 disappears, and the lateral nitrogen spring 16 of the lower die returns to its natural extension state. Through the stroke insert 17, the slider 14 is pushed to slide horizontally outward along the guide block 15 to the initial position, realizing the automatic reset of the lateral bending component. The side push plate 11 completely disengages from the formed end cap pipe 21 to avoid scratching the workpiece. The upper die continues to move upward, and the ejector plate 3, the lower bending block 7, and the movable lower pressing block 6 all disengage from the surface of the formed workpiece. The vertical pressure applied to the floating plate 8 disappears, and the longitudinal nitrogen spring 19 returns to its natural lifting state, pushing the floating plate 8 to move vertically upward along the guide rod 20 to reset. During the upward movement of the floating plate 8, the formed end cap pipe 21 is simultaneously pushed out of the bending working area of ​​the die, so that the workpiece is completely separated from the bending components of the upper and lower dies, realizing automatic ejection.

[0061] S5. Workpiece removal

[0062] The upper die continues to move upward to the upper stop point of the punch press, and the die returns to the initial state of full opening. All die components are reset and ready for the next processing. At this time, the manual or unloading device can directly remove the formed hollow hook of the automobile exhaust pipe head from the floating plate 8 to complete a single complete cold stamping bending process.

[0063] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0064] Other parts of this invention that are not detailed herein are all prior art and will not be described further here.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hollow hook bending die, characterized in that, The upper mold part includes an upper mold part and a lower mold part. The upper mold part includes an upper mold base (1), an upper pad plate (2) fixedly connected to the bottom of the upper mold base (1), a material ejector plate (3) fixedly connected to the bottom of the upper pad plate (2), a material ejector plate insert (4) fixedly connected to the bottom of the material ejector plate (3), inserts (5) symmetrically fixedly connected to the bottom of the upper mold base (1) on both sides of the upper pad plate (2), a lower pressing bending block (7) fixedly connected to the bottom of the material ejector plate insert (4), and a movable lower pressing block (6) that is inclined and slidably connected to one side of the lower pressing bending block (7). The lower mold portion includes a longitudinal bending component and a lateral bending component; The longitudinal bending assembly includes a lower mold base (18), a longitudinal nitrogen spring (19) fixedly connected to the top of the lower mold base (18), a float plate (8) connected to the top of the longitudinal nitrogen spring (19), rotating pins (9) symmetrically arranged on both sides of the upper end of the float plate (8), and a bending block body (10) symmetrically and movably connected on both sides of the upper end of the float plate (8) through the rotating pins (9). The lateral bending assembly includes side push plates (11) symmetrically arranged on both sides of the floating material plate (8) at the upper end of the lower mold base (18), sliders (14) fixedly connected to both sides of the lower mold base (18) through the side push plates (11), and a template (12) fixedly connected to the top of the slider (14) with screws on the side facing the insert knife (5). The upper mold part and the lower mold part work together to first bend the workpiece to 90° by pressing down the bending block (7) and the movable pressing block (6) to join the longitudinal bending assembly, and then bend it to greater than 105° by pushing the lateral bending assembly from the inside of the insert knife (5).

2. The hollow hook bending die as described in claim 1, characterized in that, The structure consisting of the pressing bending block (7) and the movable pressing block (6) is an isosceles trapezoid with rounded chamfers on both sides of the bottom end of the isosceles trapezoid.

3. The hollow hook bending die as described in claim 1, characterized in that, The side push plate (11) is inclined at the end of the pressing bending block (7) and the movable pressing block (6), and the contact surface between the slider (14) and the insert (5) is a matching inclined structure.

4. The hollow hook bending die as described in claim 1, characterized in that, The lower mold base (18) is slidably sleeved with a guide rod (20) on the side near the longitudinal nitrogen spring (19). The top end of the guide rod (20) is fixedly connected to the bottom of the floating material plate (8). There are two guide rods (20).

5. The hollow hook bending die as described in claim 1, characterized in that, The top of the lower mold base (18) is fixedly connected to guide blocks (15) on both sides of the slider (14). The guide blocks (15) are inverted L-shaped structures, and the slider (14) is horizontally fitted and slidably connected between the two guide blocks (15).

6. The hollow hook bending die as described in claim 1, characterized in that, The bottom end of the slider (14) is fixedly connected to a stroke insert (17), which abuts against the extension end of the transverse nitrogen spring (16).

7. The hollow hook bending die as described in claim 1, characterized in that, The tail of the transverse nitrogen spring (16) is set on the nitrogen spring pad (13), and the upper end of the lower mold base (18) is provided with an inner groove (1701) on the side facing the transverse nitrogen spring (16).

8. The hollow hook bending die as described in claim 7, characterized in that, The transverse nitrogen spring (16) and nitrogen spring pad (13) inside the inner groove (1701) are both disposed inside the inner groove (1701).

9. The hollow hook bending die as described in claim 1, characterized in that, The floating plate (8) has a workpiece placement groove, and the floating plate (8) has a horizontally placed end cap pipe fitting (2) through the workpiece placement groove.

10. A method for bending a hollow hook based on a hollow hook bending die as described in any one of claims 1 to 9, characterized in that, The bending steps include the following: S1. Drive the upper mold part to the upper stop point, the mold opens, the longitudinal nitrogen spring (19) lifts the floating plate (8) to the highest position, the transverse nitrogen spring (16) pushes the slider (14) to the initial position, and the pier head pipe fitting (21) is horizontally placed into the workpiece placement groove of the floating plate (8) to complete the positioning. S2, drive the upper mold part to move down, the movable lower pressure block (6) contacts the pier head pipe fitting (21) and slides down along the inclined surface of the lower pressure bending block (7) and closes to form a combined mold, the ejector plate (3) presses the pier head pipe fitting (21) and pushes the floating plate (8) to overcome the lifting force of the longitudinal nitrogen spring (19) and move down, the bending block body (10) rotates inward around the rotating pin (9) so that the pier head pipe fitting (21) is bent into 90°; S3. The upper mold continues to move downwards. The insert (5) fits against the template (12) on the slider (14) through the inclined surface, converting the vertical pressure into a horizontal thrust. This pushes the slider (14) to overcome the force of the horizontal nitrogen spring (16) and slide horizontally inwards along the guide block (15). The slider (14) drives the side push plate (11) to push the 90° bent end pipe (21) inwards. After the end pipe (21) is bent into a symmetrical structure greater than 105°, the upper mold stops moving downwards. S4. The upper mold part moves upward, the insert (5) separates from the slider (14), the horizontal nitrogen spring (16) pushes the slider (14) to return to horizontal reset, the upper mold part continues to move upward, the ejector plate (3) separates from the head pipe fitting (21), the vertical nitrogen spring (19) lifts the floating plate (8) to return to reset, and pushes the formed head pipe fitting (21) out of the working area.

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