Die and method for inward flanging of port of thin pipe fitting

Abstract

The invention discloses a die and method for inward flanging of a port of a thin pipe fitting, and relates to the technical field of inward flanging of a bottom port of the thin pipe fitting, the die comprises an upper die and a lower die, the lower die comprises a base, a lower cushion plate and a concave die plate which are fixedly connected into a whole from bottom to top in sequence, a concave cavity is formed in the top surface of the concave die plate, and the concave cavity is communicated with the upper die. A first male die fixedly arranged on the top surface of the lower base plate is arranged in the concave cavity, an arc-shaped groove is formed in the top surface of the first male die, and an arc-shaped protrusion is fixedly arranged at the groove bottom of the arc-shaped groove. The upper die comprises an upper support, a connecting plate and an upper padding plate which are sequentially and fixedly connected into a whole from top to bottom, the top surface of the upper support is fixedly arranged on a punching head of a punching machine, and a limiting plate and a discharging plate which are sequentially and fixedly connected into a whole are arranged below the upper padding plate. The device has the beneficial effects that the inner flanging efficiency of the bottom end opening of the thin pipe fitting is greatly improved, and the flanging quality of the bottom end opening of the thin pipe fitting is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of inverting the bottom port of a thin pipe fitting, and particularly to a mold and method for inverting the port of a thin pipe fitting. Background Art

[0002] The structure of a strip material produced is as Figures 1 to 2 shown. It includes a long strip thin plate 1, and a plurality of thin pipe fittings 2 are formed by extending and molding at intervals along the length direction on the bottom surface of the long strip thin plate 1. The thin pipe fittings 2 are integrally fixed to the long strip thin plate 1. The bottom port and the top port of the thin pipe fitting 2 are both communicated with the outside. The length of the thin pipe fitting 2 is 8 mm, and the inner diameter of the thin pipe fitting 2 is 1.5 mm. Technologically, it is required to turn the bottom ports of the respective thin pipe fittings 2 on the strip material inward by a certain angle, and the flanging direction is as Figure 2 shown by the arrow in the figure, so that the bottom port of the thin pipe fitting 2 has a certain arc. The structure of the thin pipe fitting 2 after inverting the edge is as Figure 3 shown. After inverting the edges of the respective thin pipe fittings 2 on the strip material, the strip material can be provided to customers for use.

[0003] Due to the very small size of the length and inner diameter of the thin pipe fitting 2, it is simply impossible for a fitter to invert the bottom port of the thin pipe fitting 2 [The reason is that: the size of the thin pipe fitting 2 is quite small, and there is no special fixture to stably hold it, and thus it is impossible to use a special tool to invert the inner port of the thin pipe fitting 2]. Therefore, there is an urgent need for a mold and method that can invert the bottom ports of the respective thin pipe fittings 2 on the strip material inward. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a mold and method for inverting the port of a thin pipe fitting that greatly improves the efficiency of inverting the bottom port of the thin pipe fitting and improves the quality of inverting the bottom port of the thin pipe fitting.

[0005] The purpose of the present invention is achieved by the following technical solutions: A mold for inverting the port of a thin pipe fitting includes an upper mold and a lower mold. The lower mold includes a base, a lower backing plate, and a concave template fixedly connected to each other in sequence from bottom to top. A concave cavity is formed on the top surface of the concave template, and a first punch fixedly arranged on the top surface of the lower backing plate is arranged in the concave cavity. An arc-shaped groove is formed on the top surface of the first punch, and an arc-shaped protrusion is fixedly arranged at the bottom of the arc-shaped groove; Rectangular rods are fixedly provided on both the left and right side walls in the concave cavity of the concave template. Sliders are slidably sleeved on both rectangular rods. The two sliders are respectively located on the left and right sides of the first punch. Horizontal springs are sleeved on both rectangular rods. The two ends of the horizontal spring are respectively fixedly provided on the inner wall of the concave cavity and the slider. Semi-circular small holes are provided on the inner end faces of the two sliders above the first punch. Inclined surfaces are provided on the outer ends of the two sliders. A first vertical spring is fixedly provided in the base. The top end of the first vertical spring is connected to a first force transmission rod, and the first force transmission rod sequentially penetrates upward through the lower backing plate and the concave template. The upper die includes an upper bolster, a connecting plate, and an upper backing plate fixedly connected together from top to bottom. The top surface of the upper bolster is fixedly provided on the punching head of the punching machine. A limiting plate and a stripper plate fixedly connected together in sequence are provided below the upper backing plate. A gap A is formed between the limiting plate and the upper backing plate. The stripper plate is fixedly connected to the top end of the first force transmission rod. A gap B is formed between the bottom surface of the stripper plate and the top surface of the concave template. Two inserting plates are fixedly provided on the bottom surface of the connecting plate. The two inserting plates sequentially penetrate downward through the upper backing plate, the limiting plate, and the stripper plate, and the wedge-shaped surfaces of the two inserting plates are respectively directly above the two inclined surfaces of the two sliders. A fixing rod is fixedly provided on the bottom surface of the connecting plate and sequentially penetrates downward through the connecting plate, the upper backing plate, the limiting plate and extends into the stripper plate. A second punch is fixedly provided on the bottom surface of the fixing rod. A conical groove matching the arc-shaped protrusion is provided on the bottom surface of the second punch. The outer diameter of the second punch is equal to the inner diameter of the thin pipe fitting.

[0006] The lower backing plate and the base are detachably connected together by bolts.

[0007] The two sliders are symmetrically arranged about the first punch on the left and right.

[0008] A blind groove is provided in the outer end face of the slider, and the blind groove of the slider is sleeved on the rectangular rod.

[0009] The diameter of the semi-circular small hole is equal to the outer diameter of the thin pipe fitting.

[0010] A pressure pad insert is fixedly provided in the stripper plate. The bottom end of the fixing rod extends into the inner cavity of the pressure pad insert, and the second punch is located in the inner cavity of the pressure pad insert.

[0011] A method for inverting the port of a thin pipe fitting includes the following steps: S1. Pull the strip from front to back into the area surrounded by the stripper plate and the concave template through the material pulling mechanism, and ensure that the first thin pipe fitting on the strip is directly below the inner cavity of the pressure pad insert. S2. Control the punch head of the stamping machine to move downward. The punch head drives the upper support to move downward, and the upper support drives the connecting plate and the upper backing plate to move downward synchronously, thereby driving the fixed rod, the second punch and the two inserting plates to move downward synchronously relative to the stationary unloading plate. Among them, the wedge-shaped surfaces of the two inserting plates move respectively towards the inclined surfaces of the two sliders, and the second punch gradually extends into the inner hole of the thin pipe fitting; After the bottom surface of the upper backing plate contacts the top surface of the limit plate, the wedge-shaped surfaces of the two inserting plates are respectively directly above the inclined surfaces of the two sliders. At the same time, the second punch just extends into the inner hole of the thin pipe fitting, and the distance between the bottom surface of the second punch and the bottom surface of the thin pipe fitting is 0.6 mm; S3. As the punch head of the stamping machine continues to move downward, the punch drives the upper support to continue to move downward. The upper support drives the connecting plate, the upper backing plate, the limit plate and the unloading plate to move downward synchronously relative to the stationary concave template, thereby driving the fixed rod, the second punch and the two inserting plates to move downward synchronously relative to the stationary concave template. The unloading plate also presses the long strip thin plate and the thin pipe fitting of the strip material downward; After the upper support moves downward for a certain distance, the wedge-shaped surfaces of the two inserting plates respectively contact the inclined surfaces of the two sliders. At the same time, the lower end of the thin pipe fitting enters the area surrounded by the semi-circular small holes of the two sliders; S4. As the punch head of the stamping machine continues to move downward, the punch drives the upper support to continue to move downward. The upper support drives the connecting plate, the upper backing plate, the limit plate and the unloading plate to move downward synchronously relative to the stationary concave template, thereby driving the fixed rod, the second punch and the two inserting plates to move downward synchronously relative to the stationary concave template. The unloading plate continues to press the long strip thin plate and the thin pipe fitting of the strip material downward. At the same time, the two inserting plates respectively push the two sliders inward, so that the semi-circular small holes of the two sliders move respectively towards the direction of the thin pipe fitting; After the upper support moves downward for a certain distance, the inner end surfaces of the two inserting plates respectively contact the inner end surfaces of the two sliders. At the same time, the inner walls of the semi-circular small holes of the two sliders are both in contact with the outer wall of the thin pipe fitting to protect the outer wall of the thin pipe fitting; S5. As the punch head of the stamping machine continues to move downward, the punch drives the upper support to continue to move downward. The upper support drives the connecting plate, the upper backing plate, the limit plate and the unloading plate to move downward synchronously relative to the stationary concave template, thereby driving the fixed rod, the second punch and the two inserting plates to move downward synchronously relative to the stationary concave template. The unloading plate continues to press the long strip thin plate and the thin pipe fitting of the strip material downward. Among them, when the tapered groove of the second punch and the arc-shaped protrusion of the first punch are gradually matched, the bottom port of the thin pipe fitting gradually turns inward. When the tapered groove and the arc-shaped protrusion are completely matched, the bottom port of the thin pipe fitting is finally turned inward, thereby completing the inward flanging of the bottom port of a thin pipe fitting; S6. Workers repeat the operations of steps S2 to S5 in this way, and the bottom ports of all the thin pipe fittings 2 on the strip material can be turned inward.

[0012] The present invention has the following advantages: greatly improving the flanging efficiency of the bottom port of a thin pipe fitting and improving the flanging quality of the bottom port of a thin pipe fitting. Description of the Drawings

[0013] Figure 1 is a schematic structural diagram of a certain strip material; Figure 2 is Figure 1 C-C sectional view of; Figure 3 is a schematic structural diagram of the thin pipe fitting after inward flanging; Figure 4 is a schematic structural diagram of the present invention; Figure 5 is Figure 4 partial enlarged view of part D of; Figure 6 is a schematic structural diagram of the first punch; Figure 7 is Figure 6 partial enlarged view of part E of; Figure 8 is a schematic structural diagram of the slider; Figure 9 is Figure 8 top view of; Figure 10 is a connection schematic diagram of the fixed rod and the second punch; Figure 11 is Figure 10 partial enlarged view of part F of; Figure 12 is a schematic structural diagram of the insertion plate; Figure 13 is a schematic structural diagram of the blank holder insert; Figure 14 is a schematic diagram of the first thin pipe fitting on the strip material being directly below the inner cavity of the blank holder insert; Figure 15 is Figure 14 partial enlarged view of part G of; Figure 16 is a schematic diagram of the second punch extending into the inner hole of the thin pipe fitting; Figure 17 is Figure 16 partial enlarged view of part H of; Figure 18 is a schematic diagram of the lower end of the thin pipe fitting entering the area enclosed by the semi-circular small holes of the two sliders; Figure 19 is Figure 18 partial enlarged view of part J of; Figure 20Schematic diagram where the inner walls of the semi-circular small holes of two sliders are in contact with the outer wall of the thin pipe fitting; Figure 21 is Figure 20 Partial enlarged view of part M; Figure 22 Schematic diagram of turning the bottom port of the thin pipe fitting inwards; Figure 23 is Figure 22 Partial enlarged view of part N; Figure 24 is Figure 23 Partial enlarged view of part P; In the figure: 1 - long strip thin plate, 2 - thin pipe fitting; 3 - base, 4 - lower backing plate, 5 - cavity die plate, 6 - first punch, 7 - arc-shaped groove, 8 - arc-shaped protrusion, 9 - rectangular rod, 10 - slider, 11 - horizontal spring, 12 - semi-circular small hole, 13 - inclined plane, 14 - first vertical spring, 15 - first force transmission rod; 16 - upper support, 17 - upper backing plate, 18 - limit plate, 19 - stripper plate, 20 - inserting plate, 21 - wedge-shaped surface, 22 - fixing rod, 23 - second punch, 24 - tapered groove; 25 - blind groove, 26 - blanking insert. Specific implementation mode

[0014] The following further describes the present invention with reference to the accompanying drawings. The protection scope of the present invention is not limited to the following: As Figures 4 to 13 shown, a die for inwards turning the port of a thin pipe fitting includes an upper die and a lower die. The lower die includes a base 3, a lower backing plate 4 and a cavity die plate 5 which are fixedly connected together in sequence from bottom to top. The lower backing plate 4 and the base 3 are detachably connected together by bolts. A cavity is provided on the top surface of the cavity die plate 5, and a first punch 6 fixedly arranged on the top surface of the lower backing plate 4 is arranged in the cavity. An arc-shaped groove 7 is provided on the top surface of the first punch 6, and an arc-shaped protrusion 8 is fixedly arranged at the bottom of the arc-shaped groove 7.

[0015] Rectangular rods 9 are fixedly provided on both the left and right side walls within the concave cavity of the concave template 5. Sliders 10 are slidably sleeved on both rectangular rods 9. Blind slots 25 are formed in the outer end faces of the sliders 10, and the blind slots 25 of the sliders 10 are sleeved on the rectangular rods 9. The two sliders 10 are symmetrically arranged about the first punch 6 on the left and right, and the two sliders 10 are respectively located on the left and right sides of the first punch 6. Horizontal springs 11 are sleeved on both rectangular rods 9, and the two ends of the horizontal springs 11 are respectively fixedly provided on the inner wall of the concave cavity and the sliders 10. Semi-circular small holes 12 located above the first punch 6 are formed in the inner end faces of the two sliders 10. The diameter of the semi-circular small holes 12 is equal to the outer diameter of the thin pipe fitting 2. Inclined surfaces 13 are formed at the outer ends of the two sliders 10. A first vertical spring 14 is fixedly provided within the base 3, and the top end of the first vertical spring 14 is fixedly connected to a first force transmission rod 15. The first force transmission rod 15 sequentially penetrates upward through the lower backing plate 4 and the concave template 5.

[0016] The upper die includes an upper bolster 16, a connecting plate, and an upper backing plate 17 fixedly connected together in sequence from top to bottom. The top surface of the upper bolster 16 is fixedly provided on the punching head of the punching machine. Below the upper backing plate 17, a limiting plate 18 and a stripper plate 19 fixedly connected together in sequence are provided. A gap A is formed between the limiting plate 18 and the upper backing plate 17. The stripper plate 19 is fixedly connected to the top end of the first force transmission rod 15. A gap B is formed between the bottom surface of the stripper plate 19 and the top surface of the concave template 5.

[0017] Two inserting plates 20 are fixedly provided on the bottom surface of the connecting plate. The two inserting plates 20 sequentially penetrate downward through the upper backing plate 17, the limiting plate 18, and the stripper plate 19, and the wedge-shaped surfaces 21 of the two inserting plates 20 are respectively located directly above the two inclined surfaces 13 of the two sliders 10. A fixing rod 22 is fixedly provided on the bottom surface of the connecting plate and sequentially penetrates downward through the connecting plate, the upper backing plate 17, the limiting plate 18 and extends into the stripper plate 19. A second punch 23 is fixedly provided on the bottom surface of the fixing rod 22. A tapered groove 24 matching the arc-shaped protrusion 8 is formed on the bottom surface of the second punch 23. The outer diameter of the second punch 23 is equal to the inner diameter of the thin pipe fitting 2.

[0018] A pressure pad insert 26 is fixedly provided within the stripper plate 19. The bottom end of the fixing rod 22 extends into the inner cavity of the pressure pad insert, and the second punch 23 is located within the inner cavity of the pressure pad insert 26.

[0019] A method for inverting the port of a thin pipe fitting includes the following steps: S1. Through a material pulling mechanism, the strip material as shown in Figures 1 to 2 is pulled from front to back into the area enclosed by the stripper plate 19 and the concave template 5, and it is ensured that the first thin pipe fitting 2 on the strip material is directly below the inner cavity of the pressure pad insert 26, as shown in Figures 14 to 15 shown; S2. Control the punch head of the stamping machine to move downward. The punch head drives the upper support 16 to move downward. The upper support 16 drives the connecting plate and the upper backing plate 17 to move downward synchronously, and further drives the fixing rod 22, the second punch 23 and the two inserting plates 20 to move downward synchronously relative to the stationary unloading plate 19. Among them, the wedge surfaces 21 of the two inserting plates 20 move toward the inclined surfaces 13 of the two sliders 10 respectively, and the second punch 23 gradually extends into the inner hole of the thin pipe fitting 2; After the bottom surface of the upper backing plate 17 contacts the top surface of the limit plate 18, the wedge surfaces 21 of the two inserting plates 20 are respectively located directly above the inclined surfaces 13 of the two sliders 10. At the same time, the second punch 23 just extends into the inner hole of the thin pipe fitting 2, as Figures 16 to 17 shown, and the distance between the bottom surface of the second punch 23 and the bottom surface of the thin pipe fitting 2 is 0.6 mm; S3. As the punch head of the stamping machine continues to move downward, the punch drives the upper support 16 to continue to move downward. The upper support 16 drives the connecting plate, the upper backing plate 17, the limit plate 18 and the unloading plate 19 to move downward synchronously relative to the stationary concave template 5, and further drives the fixing rod 22, the second punch 23 and the two inserting plates 20 to move downward synchronously relative to the stationary concave template 5. The unloading plate 19 also presses the strip thin plate 1 with the strip material and the thin pipe fitting 2 downward; After the upper support 16 moves downward a certain distance, the wedge surfaces 21 of the two inserting plates 20 respectively contact the inclined surfaces 13 of the two sliders 10. At the same time, the lower end of the thin pipe fitting 2 enters the area surrounded by the semi-circular small holes 12 of the two sliders 10, as Figures 18 to 19 shown; S4. As the punch head of the stamping machine continues to move downward, the punch drives the upper support 16 to continue to move downward. The upper support 16 drives the connecting plate, the upper backing plate 17, the limit plate 18 and the unloading plate 19 to move downward synchronously relative to the stationary concave template 5, and further drives the driving fixing rod 22, the second punch 23 and the two inserting plates 20 to move downward synchronously relative to the stationary concave template 5. The unloading plate 19 continues to press the strip thin plate 1 with the strip material and the thin pipe fitting 2 downward. At the same time, the two inserting plates 20 respectively push the two sliders 10 inward, so that the semi-circular small holes 12 of the two sliders 10 move toward the thin pipe fitting 2 respectively; After the upper support 16 moves downward a certain distance, the inner end surfaces of the two inserting plates 20 respectively contact the inner end surfaces of the two sliders 10. At the same time, the inner walls of the semi-circular small holes 12 of the two sliders 10 are both in contact with the outer wall of the thin pipe fitting ② to protect the outer wall of the thin pipe fitting 2, as Figures 20 to 21 shown; S5. As the punch head of the stamping machine continues to move downward, the punch drives the upper support 16 to move downward continuously. The upper support 16 drives the connecting plate, the upper backing plate 17, the limiting plate 18 and the stripper plate 19 to move downward synchronously relative to the stationary concave template 5, thereby driving the fixed rod 22, the second punch 23 and the two inserting plates 20 to move downward synchronously relative to the stationary concave template 5. The stripper plate 19 continues to press the long strip thin plate 1 and the thin pipe fitting 2 of the strip material. Among them, when the tapered groove 24 of the second punch 23 and the arc-shaped protrusion 8 of the first punch 6 are gradually mating, the bottom port of the thin pipe fitting 2 gradually turns inward. When the tapered groove 24 and the arc-shaped protrusion 8 are completely mated, the bottom port of the thin pipe fitting 2 is finally turned inward, as Figures 22 to 24 shown. Then, the inward flanging of the bottom port of one thin pipe fitting 2 is completed. The structure of the thin pipe fitting 2 after flanging is as Figure 3 shown; S6. Workers repeat the operations in steps S2 - S5 in this way, and the bottom ports of all the thin pipe fittings 2 on the strip material can be turned inward.

[0020] Among them, it can be seen from steps S2 - S5 that only by controlling the downward movement of the punch head of the stamping machine, the second punch 23 can first extend into the inner hole of the thin pipe fitting 2, then protect the outer wall of the thin pipe fitting 2 through the semi-circular small holes 12 of the two sliders 10, and then push up the material around the bottom port of the thin pipe fitting 2 through the arc-shaped groove 7 and the arc-shaped protrusion 8 of the first punch 6, thus finally completing the inward flanging of the bottom port of the thin pipe fitting 2. It can be seen that with one downward movement of the punch head of the stamping machine, this die can complete the inward flanging of the bottom port of the thin pipe fitting 2 with a length of only 8 mm and an inner diameter of only 1.5 mm, thereby greatly improving the flanging efficiency of the bottom port of the thin pipe fitting 2. Moreover, it also solves the technical problem that the prior art cannot process the thin pipe fitting 2 with a length of only 8 mm and an inner diameter of only 1.5 mm.

[0021] In addition, since the outer wall of the thin pipe fitting 2 is protected by the semi-circular small holes 12 of the two sliders 10 and the second punch 23 protects the inside of the thin pipe fitting 2, when the arc-shaped groove 7 and the arc-shaped protrusion 8 of the first punch 6 push up the material around the bottom port of the thin pipe fitting 2, the thin pipe fitting 2 will not be bent and deformed, thereby greatly improving the quality of the inward flanging of the bottom port of the thin pipe fitting 2 and meeting the requirements of customers.

[0022] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A die for inverting the edge of the port of a thin pipe fitting, characterized in that: It includes an upper die and a lower die. The lower die includes a base (3), a lower backing plate (4), and a cavity plate (5) fixedly connected to each other in sequence from bottom to top. A concave cavity is formed on the top surface of the cavity plate (5), and a first punch (6) fixedly arranged on the top surface of the lower backing plate (4) is arranged in the concave cavity. An arc-shaped groove (7) is formed on the top surface of the first punch (6), and an arc-shaped protrusion (8) is fixedly arranged at the bottom of the arc-shaped groove (7). Rectangular rods (9) are fixedly arranged on the left and right side walls in the concave cavity of the cavity plate (5). Sliders (10) are slidably sleeved on both rectangular rods (9). The two sliders (10) are respectively located on the left and right sides of the first punch (6). Horizontal springs (11) are sleeved on both rectangular rods (9). The two ends of the horizontal spring (11) are respectively fixedly arranged on the inner wall of the concave cavity and the slider (10). Semi-circular small holes (12) located above the first punch (6) are formed on the inner end surfaces of the two sliders (10). Inclined surfaces (13) are formed on the outer ends of the two sliders (10). A first vertical spring (14) is fixedly arranged in the base (3), and a first force transmission rod (15) is fixedly connected to the top end of the first vertical spring (14). The first force transmission rod (15) sequentially penetrates upward through the lower backing plate (4) and the cavity plate (5). The upper die includes an upper bolster (16), a connecting plate, and an upper backing plate (17) fixedly connected to each other in sequence from top to bottom. The top surface of the upper bolster (16) is fixedly arranged on the punching head of a punching machine. A limiting plate (18) and a stripper plate (19) fixedly connected to each other in sequence are arranged below the upper backing plate (17). A gap A is formed between the limiting plate (18) and the upper backing plate (17). The stripper plate (19) is fixedly connected to the top end of the first force transmission rod (15). A gap B is formed between the bottom surface of the stripper plate (19) and the top surface of the cavity plate (5). Two inserting plates (20) are fixedly arranged on the bottom surface of the connecting plate. The two inserting plates (20) sequentially penetrate downward through the upper backing plate (17), the limiting plate (18), and the stripper plate (19), and the wedge-shaped surfaces (21) of the two inserting plates (20) are respectively located directly above the two inclined surfaces (13) of the two sliders (10). A fixing rod (22) fixedly arranged on the bottom surface of the connecting plate sequentially penetrates downward through the connecting plate, the upper backing plate (17), the limiting plate (18) and extends into the stripper plate (19). A second punch (23) is fixedly arranged on the bottom surface of the fixing rod (22). A tapered groove (24) matched with the arc-shaped protrusion (8) is formed on the bottom surface of the second punch (23). The outer diameter of the second punch (23) is equal to the inner diameter of the thin pipe fitting (2).

2. A die for inverting the edge of the port of a thin pipe fitting according to claim 1, characterized in that: The lower backing plate (4) and the base (3) are detachably connected to each other by bolts.

3. A mold for inverting the edge of the port of a thin pipe fitting according to claim 2, characterized in that: The two sliders (10) are symmetrically arranged about the first punch (6) left and right.

4. A die for inverting the edge of the port of a thin pipe fitting according to claim 3, characterized in that: A blind groove (25) is formed in the outer end surface of the slider (10), and the blind groove (25) of the slider (10) is sleeved on the rectangular rod (9).

5. A die for inverting the edge of the port of a thin pipe fitting according to claim 4, characterized in that: The diameter of the semi-circular small hole (12) is equal to the outer diameter of the thin pipe fitting (2).

6. A die for inverting the edge of the port of a thin pipe fitting according to claim 5, characterized in that: A pressure pad insert (26) is fixedly installed inside the stripper plate (19). The bottom end of the fixing rod (22) extends into the inner cavity of the pressure pad insert, and the second punch (23) is located in the inner cavity of the pressure pad insert (26).

7. A method for in-turning the port of a thin pipe fitting, using the die for in-turning the port of a thin pipe fitting according to claim 6, characterized in that: It includes the following steps: S1. The strip material is pulled from front to back into the area enclosed by the stripper plate (19) and the concave template (5) through a material pulling mechanism, and it is ensured that the first thin pipe fitting (2) on the strip material is directly below the inner cavity of the pressure pad insert (26). S2. Control the punching head of the punching machine to move downward. The punching head drives the upper support (16) to move downward. The upper support (16) drives the connecting plate and the upper backing plate (17) to move downward synchronously, thereby driving the fixing rod (22), the second punch (23), and the two inserting plates (20) to move downward synchronously relative to the stationary stripper plate (19). Among them, the wedge-shaped surfaces (21) of the two inserting plates (20) move respectively towards the inclined surfaces (13) of the two sliders (10), and the second punch (23) gradually extends into the inner hole of the thin pipe fitting (2). After the bottom surface of the upper backing plate (17) contacts the top surface of the limit plate (18), the wedge-shaped surfaces (21) of the two inserting plates (20) are respectively directly above the inclined surfaces (13) of the two sliders (10). At the same time, the second punch (23) just extends into the inner hole of the thin pipe fitting (2), and the distance between the bottom surface of the second punch (23) and the bottom surface of the thin pipe fitting (2) is 0.6 mm. S3. As the punching head of the punching machine continues to move downward, the punch drives the upper support (16) to continue moving downward. The upper support (16) drives the connecting plate, the upper backing plate (17), the limit plate (18), and the stripper plate (19) to move downward synchronously relative to the stationary concave template (5), thereby driving the fixing rod (22), the second punch (23), and the two inserting plates (20) to move downward synchronously relative to the stationary concave template (5). The stripper plate (19) also presses the long strip thin plate (1) and the thin pipe fitting (2) of the strip material downward. After the upper support (16) moves downward a certain distance, the wedge-shaped surfaces (21) of the two inserting plates (20) respectively contact the inclined surfaces (13) of the two sliders (10). At the same time, the lower end of the thin pipe fitting (2) enters the area enclosed by the semi-circular small holes (12) of the two sliders (10). S4. As the punching head of the punching machine continues to move downward, the punch drives the upper support (16) to continue moving downward. The upper support (16) drives the connecting plate, the upper backing plate (17), the limit plate (18), and the stripper plate (19) to move downward synchronously relative to the stationary concave template (5), thereby driving the fixing rod (22), the second punch (23), and the two inserting plates (20) to move downward synchronously relative to the stationary concave template (5). The stripper plate (19) continues to press the long strip thin plate (1) and the thin pipe fitting (2) of the strip material downward. At the same time, the two inserting plates (20) respectively push the two sliders (10) inward, so that the semi-circular small holes (12) of the two sliders (10) move respectively towards the thin pipe fitting (2) direction. When the upper support (16) moves downward to a certain distance, the inner end surfaces of the two inserting plates (20) respectively contact the inner end surfaces of the two sliders (10), and at the same time, the inner walls of the semicircular holes (12) of the two sliders (10) contact the outer wall of the thin tube (2) to protect the outer wall of the thin tube (2); S5. As the punching head of the punching machine continues to move downward, the punch drives the upper support (16) to continue to move downward, and the upper support (16) drives the connecting plate, the upper pad (17), the limit plate (18) and the unloading plate (19) to move downward synchronously relative to the stationary concave template (5), thereby driving the fixing rod (22), the second punch (23) and the two insert plates (20) to move downward synchronously relative to the stationary concave template (5), and the unloading plate (19) continues to press the long thin plate (1) and the thin tube (2) with the material downward, wherein, when the tapered groove (24) of the second punch (23) and the arc-shaped protrusion (8) of the first punch (6) are gradually matched, the bottom end of the thin tube (2) gradually turns inward, and when the tapered groove (24) and the arc-shaped protrusion (8) are completely matched, the bottom end of the thin tube (2) is finally turned inward, thereby completing the inner turning of the bottom end of the thin tube (2); S6. The worker repeats the operations of steps S2 to S5 to turn the bottom ends of all the thin tubes (2) on the strip inward.

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