A double-layer thread-rolling mechanism and a double-layer thread-rolling die

Abstract

The present application relates to a double-layer threading mechanism and a double-layer threading die. The double-layer threading mechanism includes an inner threading body having threads for threading at the upper end of the inner threading; an outer threading body having threads for threading at the upper end of the outer threading body, the outer threading body being axially hollow, and the inner threading body being located inside the outer threading body and coaxially arranged with the outer threading body; an inner support body fixedly arranged between the outer threading body and the inner threading body; a first beryllium copper sleeve fixedly connected to the inside of the outer threading body and abutting against the inner support body; and a second beryllium copper sleeve fixedly connected to the outside of the inner threading body and abutting against the inner support body. The inner threading body and the outer threading body are separated by the first beryllium copper sleeve, the second beryllium copper sleeve and the inner support body, avoiding contact jamming and damage of the two threading bodies during the threading process, and taking into account the threading production efficiency and reliability.

Description

Technical Field

[0001] The present application relates to the field of bottle cap processing molds, and particularly to a double-layer thread rolling mechanism and a double-layer thread rolling mold. Background Art

[0002] Integrated inner and outer bottle caps need to be installed on many cosmetic bottles. The inner bottle cap is used for sealing, and the outer bottle cap is used for decoration. Most existing bottle caps are manufactured using molds, and common bottle caps are processed with internal threads so that the bottle cap can be screwed onto the bottle body. For cosmetic bottle caps, double-layer threads are required. In the prior art, during the injection molding of bottle caps using a double-layer thread rolling mold, two thread rolling bodies are required to roll threads on the inner bottle cap and the outer bottle cap respectively. If the inner bottle cap and the outer bottle cap are thread-rolled separately, two thread-rolling processes are required, resulting in low production efficiency. If the inner bottle cap and the outer bottle cap are thread-rolled simultaneously, the two thread rolling bodies are likely to get stuck and damage the mold, with poor reliability. Summary of the Invention

[0003] In order to solve the problem that the existing double-layer thread rolling mold cannot balance production efficiency and production reliability, the present application provides a double-layer thread rolling mechanism and a double-layer thread rolling mold, which can perform double-layer thread rolling simultaneously and avoid jamming and wear of the two thread rolling bodies, balancing production efficiency and production reliability.

[0004] In a first aspect, a double-layer thread rolling mechanism provided by the present application adopts the following technical solution:

[0005] A double-layer thread rolling mechanism, comprising:

[0006] An inner thread rolling body, the upper end of the inner thread rolling body having threads for thread rolling;

[0007] An outer thread rolling body, the upper end of the outer thread rolling body having threads for thread rolling, the outer thread rolling body being axially hollow, and the inner thread rolling body being located inside the outer thread rolling body and coaxially arranged with the outer thread rolling body;

[0008] An inner support body, the inner support body being fixedly arranged between the outer thread rolling body and the inner thread rolling body;

[0009] A first beryllium copper sleeve, the first beryllium copper sleeve being fixedly connected to the inside of the outer thread rolling body and abutting against the inner support body; and

[0010] A second beryllium copper sleeve, the second beryllium copper sleeve being fixedly connected to the outside of the inner thread rolling body and abutting against the inner support body.

[0011] By adopting the above technical solution, the inner threading body and the outer threading body are separated by the first beryllium copper sleeve, the second beryllium copper sleeve and the inner support body, avoiding contact jamming and damage of the two threading bodies during the threading process, improving the reliability of threading production. In addition, the design of the beryllium copper sleeve reduces the influence on the rotation of the threading body caused by friction, and after the beryllium copper sleeve is worn, it can be directly removed and replaced, which is convenient, fast and low-cost.

[0012] In a second aspect, a double-layer threading die provided by the present application adopts the following technical solution:

[0013] A double-layer threading die includes an upper die, a lower die and the double-layer threading mechanism as described above. The lower die and the upper die are detachably connected by fasteners. In the connected state of the lower die and the upper die, the lower die and the upper die enclose a product space. The upper ends of the inner threading body and the outer threading body are both located in the product space. The outer threading body is rotatably installed on the lower die. The lower end of the inner threading body extends to the outside of the outer threading body and is rotatably connected to the lower die. The inner support body is fixedly connected to the lower die.

[0014] By adopting the above technical solution, the double-layer threading mechanism is applied to the threading die, so that the threading parts of the inner threading body and the outer threading body are located in the product space, and threads can be threaded during the injection molding process, improving production efficiency.

[0015] Optionally, a first gear is fixedly connected to the lower end of the outer threading body, a second gear is fixedly provided at the lower end of the inner threading body, a first opening and a second opening are formed in the lower die. The first opening is used for passing through a rack that can mesh with the first gear, and the second opening is used for passing through a rack that can mesh with the second gear.

[0016] By adopting the above technical solution, the rotation of the inner threading body and the outer threading body is realized through the gear-rack transmission. The transmission structure is simple and reliable, and the inner threading body and the outer threading body are rotated through independent gear-rack transmission structures, which can meet more threading requirements.

[0017] Optionally, a ball retainer sleeve is connected between the inner threading body and the lower die, and a ball retainer sleeve is connected between the outer threading body and the lower die.

[0018] By adopting the above technical solution, the ball retainer sleeve is provided to make the rotation of the inner threading body and the outer threading body smoother and more stable, improving the reliability of the structure.

[0019] Optionally, two or more wedge blocks are slidably connected to the lower mold. The wedge blocks are circumferentially distributed around the rotation axis of the external thread body, and all the wedge blocks enclose a closed ring. The wedge blocks are slidably connected to the lower mold, and a first elastic member is connected between the wedge blocks and the lower mold. The first elastic member has an elastic tendency to drive the wedge blocks to move away from the central axis.

[0020] Wherein, one side surface of the wedge block facing the central axis is located in the product space and has a protrusion or a concave. One side surface of the wedge block away from the central axis is a first inclined surface, which is inclined outward from top to bottom and abuts against the upper mold.

[0021] By adopting the above technical solution, the slidable wedge blocks are provided. During the process of installing the upper mold onto the lower mold, the wedge blocks are pushed to move towards the product space side, so that the local protrusion or concave-shaped surface of the wedge blocks forms a part of the side wall of the product space. After the upper mold and the lower mold are separated during demolding, the wedge blocks move under the action of the first elastic member and are separated from the formed product part, avoiding interference with the product part during demolding and damaging the product part.

[0022] Optionally, a moving member and two or more clamping blocks are installed in the upper mold. The clamping blocks are circumferentially distributed around the rotation axis of the external thread body, and all the clamping blocks enclose a closed ring. The clamping blocks are slidably connected to the upper mold, and a second elastic member is connected between the clamping blocks and the upper mold. The second elastic member has an elastic tendency to drive the clamping blocks to move away from the central axis. The clamping blocks abut against one side surface of the wedge block facing the central axis.

[0023] The moving member is located inside the closed ring formed by the clamping blocks, and a second inclined surface for contacting the clamping blocks is provided on the side of the moving member. The second inclined surface is inclined outward from top to bottom. The lower end surface of the moving member is located in the product space. The moving member is slidably installed in the upper mold in the up and down direction, and a third elastic member is connected between the moving member and the upper mold. The third elastic member has an elastic tendency to drive the moving member to move upward.

[0024] By adopting the above technical solution, during the connection process of the upper mold and the lower mold, the upper mold pushes the wedge blocks to move, the wedge blocks push the clamping blocks to move, and the clamping blocks push the moving member to move. On the one hand, it ensures the fit between the wedge blocks and the clamping blocks and between the clamping blocks and the moving blocks, avoiding material leakage during product injection molding. On the other hand, it is convenient for the wedge blocks, the clamping blocks, and the moving blocks to move under the action of the corresponding elastic members when the upper mold and the lower mold are separated during the demolding process, so as to quickly separate from the product part and avoid interfering with the product part during demolding and damaging the product part.

[0025] Optionally, a material injection port is provided in the upper mold, and an internal passage is vertically provided in the moving member. The lower end of the internal passage communicates with the product space, and the upper end of the internal passage communicates with the material injection port.

[0026] By adopting the above technical solution, the material injection port is communicated with the internal passage in the moving member, so that the material is injected into the product space from top to bottom, ensuring the injection efficiency.

[0027] Optionally, a telescopic connecting pipe is connected between the upper end of the moving member and the upper mold. One end of the connecting pipe communicates with the material injection port, and the other end communicates with the internal passage.

[0028] By adopting the above technical solution, since the moving member moves up and down, a telescopic connecting pipe is used to communicate the material injection port and the internal passage, improving the injection reliability.

[0029] Optionally, the connecting pipe is a corrugated pipe.

[0030] By adopting the above technical solution, a corrugated pipe type connecting pipe is used, which has a low cost and can be cut according to requirements, making it more convenient to use.

[0031] Optionally, the lower end of the moving member abuts against the upper end of the internal thread body.

[0032] By adopting the above technical solution, the lower end of the moving member abuts against the upper end of the internal thread body, which can be used to injection mold a ring-shaped hollow product part, with a high degree of customization.

[0033] In summary, the present application includes at least one of the following beneficial technical effects:

[0034] The use of a beryllium copper sleeve isolates the two thread bodies, preventing the two thread bodies from coming into contact during the simultaneous threading process and avoiding jamming, thereby improving production reliability while ensuring production efficiency;

[0035] The beryllium copper sleeve is easy to replace after wear, convenient and fast, and has a low cost;

[0036] During the connection process of the upper mold and the lower mold, the upper mold pushes the wedge block to move, then the wedge block pushes the clamping block to move, and then the clamping block pushes the moving block to move, ensuring that the lower end of the moving block can abut against the upper end of the internal thread body to meet the shape requirements of the product space. In addition, during the demolding process, after the upper mold and the lower mold are separated, the wedge block, the clamping block, and the moving block move and reset under the action of the elastic member to separate from the product part, thereby avoiding damage to the product part during demolding. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a three-dimensional structural schematic diagram of a double-layer threading mechanism.

[0038] Figure 2 Yes Figure 1 is the explosion schematic diagram of

[0039] Figure 3 is the three-dimensional structure schematic diagram of a double-layer screw die

[0040] Figure 4 Yes Figure 3 is the front view sectional schematic diagram of

[0041] Figure 5 Yes Figure 4 is the enlarged schematic diagram of A in

[0042] Figure 6 Yes Figure 5 is the enlarged schematic diagram of B in

[0043] Figure 7 is the three-dimensional structure schematic diagram of the product parts produced by injection molding through a double-layer screw die from two perspectives

[0044] Figure 8 is the side view sectional schematic diagram of the product parts

[0045] Explanation of reference numerals: 1. First template; 2. Second template; 3. Third template; 4. Fourth template; 5. Fifth template; 6. Sixth template; 7. Seventh template; 8. Eighth template; 9. Ninth template; 10. Tenth template; 11. Eleventh template; 12. Avoidance space; 13. Third elastic member; 14. Connecting pipe; 15. Moving member; 16. Internal channel; 17. Through space; 18. Second elastic member; 20. Outer support body; 21. Outer screw body; 22. First beryllium copper sleeve; 23. Inner support body; 24. Second beryllium copper sleeve; 25. Ball retaining sleeve; 26. First gear; 27. Second gear; 28. Inner screw body; 29. Clamping block; 31. Second inclined surface; 33. Product space; 34. Wedge block; 35. First elastic member; 38. Forming surface; 39. First inclined surface; 100. Upper die; 200. Lower die; 300. First opening; 400. Second opening; 500. Injection port; 600. Fastener; 700. Product parts; 701. Marking surface; 702. External thread surface; 703. Internal thread surface; 800. Screw mechanism. Detailed implementation manners

[0046] The following further describes the present application in detail with reference to the accompanying drawings.

[0047] Combined with the attached Figure 1 and the attached Figure 2As shown in the figure, the present invention discloses a double-layer threading mechanism 800, which includes an inner threading body 28, an outer threading body 21, an inner support body 23, a first beryllium copper sleeve 22, and a second beryllium copper sleeve 24. Specifically, the upper end of the outer threading body 21 has threads for threading, and the outer threading body 21 is axially hollow for accommodating the inner threading body 28. The inner threading body 28 is located inside the outer threading body 21 and is coaxially arranged with the outer threading body 21. The upper end of the inner threading body 28 also has threads for threading. By rotating the outer threading body 21 and the inner threading body 28, the outer layer and the inner layer threads on the bottle cap product can be respectively threaded out. In actual use, the outer threading body 21 and the inner threading body 28 can be driven to rotate simultaneously, so as to thread out the outer layer and the inner layer threads at the same time, improving the production efficiency. Of course, only the outer threading body 21 can be driven to rotate to thread out the outer layer threads, or only the inner threading body 28 can be driven to rotate to thread out the inner layer threads, meeting more threading requirements. The inner support body 23 is arranged between the outer threading body 21 and the inner threading body 28 for separating the outer threading body 21 and the inner threading body 28. It is avoided that the two threading bodies come into contact, get stuck and wear during the simultaneous rotation process, ensuring the threading efficiency and improving the reliability of the threading production. In addition, the inner support body 23 is fixedly arranged to prevent the inner support body 23 from rotating with the outer threading body 21 or the inner threading body 28. The first beryllium copper sleeve 22 is fixedly connected to the inner side of the outer threading body 21 and abuts against the inner support body 23, and the second beryllium copper sleeve 24 is fixedly connected to the outer side of the inner threading body 28 and abuts against the inner support body 23. The beryllium copper material is an elastic material and a wear-resistant material with low price and wide application. The beryllium copper sleeves are arranged between the outer threading body 21 and the inner support member and between the inner threading body 28 and the inner support member as wear consumables, reducing the wear of the inner threading body 28 and the outer threading body 21, and the replacement is also convenient and fast, reducing the production cost.

[0048] Combined with the attached Figure 1 to the attached Figure 6 As shown in the figure, the present invention also discloses a double-layer threading die, which includes an upper die 100, a lower die 200, and the above-mentioned double-layer threading mechanism 800. Specifically, the following embodiments are provided in this application.

[0049] In the embodiment of the present application, the lower die 200 and the upper die 100 in the double-layer knurling die are detachably connected by fasteners 600. When the lower die 200 and the upper die 100 are in a connected state, the lower die 200 and the upper die 100 enclose a product space 33. The upper ends of the internal knurling body 28 and the external knurling body 21 in the knurling mechanism 800 are both located in the product space 33. By rotating the internal knurling body 28 and the external knurling body 21, threads can be knurled during the injection molding process, improving production efficiency. The external knurling body 21 and the internal knurling body 28 are both rotatably installed on the lower die 200, and the lower end of the internal knurling body 28 extends to the outside of the external knurling body 21 and is then rotatably installed on the lower die 200, while the internal support body 23 is fixedly connected to the lower die 200. It should be noted that in this embodiment, the upper ends of the external knurling body 21, the internal knurling body 28, and the support body all extend into the product space 33, that is: the upper ends of the external knurling body 21, the internal knurling body 28, and the support body serve as a part of the side wall of the product space 33.

[0050] Specifically, in this embodiment, the upper die 100 includes, from top to bottom, a first template 1, a second template 2, a third template 3, and a fourth template 4, and the lower die 200 includes, from top to bottom, a fifth template 5, a sixth template 6, a seventh template 7, an eighth template 8, a ninth template 9, a tenth template 10, and an eleventh template 11. The upper die 100 and the lower die 200 are detachably installed using four fastening bolts.

[0051] In a further setting, a first gear 26 is fixedly connected to the lower end of the external knurling body 21, and a second gear 27 is fixedly provided at the lower end of the internal knurling body 28. A first opening 300 is formed in the sixth template 6 of the lower die 200, and a second opening 400 is formed in the seventh template 7 of the lower die 200. The first opening 300 is used for passing through a rack (not shown) that can mesh with the first gear 26, and the second opening 400 is used for passing through a rack that can mesh with the second gear 27. The rotation of the internal knurling body 28 and the external knurling body 21 is achieved through the gear-rack transmission. In actual application, the rack for meshing with the first gear 26 and the rack for meshing with the second gear 27 can operate synchronously, so that the rotation of the first gear 26 and the second gear 27 is synchronous, enabling the internal knurling body 28 and the external knurling body 21 to knurl simultaneously. This improves production efficiency. In addition, the rotation driving method of the knurling body includes but is not limited to the gear-rack transmission method in this embodiment. The gear-rack transmission method has the advantages of simple structure and reliable transmission, and the two groups of gear-rack transmissions can also be independently driven to achieve the individual knurling processing of the external knurling body 21 and the internal knurling body 28, meeting more production requirements.

[0052] In a further setting, a ball retainer sleeve 25 is connected between the internal knurling body 28 and the lower die 200 and between the external knurling body 21 and the lower die 200, making the rotation of the internal knurling body 28 and the external knurling body 21 smoother and more stable.

[0053] The present application also provides a more preferred embodiment in terms of demolding.

[0054] Specifically, more than two wedge-shaped blocks 34 are slidably connected to the lower mold 200. The wedge-shaped blocks 34 are circumferentially distributed with the rotation axis of the external thread body 21 as the central axis, and all the wedge-shaped blocks 34 enclose a closed ring. The wedge-shaped blocks 34 are slidably connected to the lower mold 200, and a first elastic member 35 is connected between the wedge-shaped blocks 34 and the lower mold 200. The first elastic member 35 has an elastic tendency to drive the wedge-shaped blocks 34 to move away from the central axis. Among them, one side surface of the wedge-shaped block 34 facing the central axis is located in the product space 33 and has a protrusion or a concave, and the side surface of the wedge-shaped block 34 away from the central axis is a first inclined surface 39. The first inclined surface 39 is inclined outward from top to bottom and abuts against the upper mold 100.

[0055] In this embodiment, an external support body 20 is fixedly arranged in the lower mold 200, and the wedge-shaped blocks 34 are slidably mounted on the external support body 20. There are two wedge-shaped blocks 34 which are symmetrically distributed left and right. Both wedge-shaped blocks 34 are in a ring shape of 180°. When the two wedge-shaped blocks 34 are fitted together, they just form a closed circular ring. The end surface of the wedge-shaped block 34 facing the central axis is located in the product space 33, that is to say, the end surface of the wedge-shaped block 34 facing the central axis serves as a part of the side wall of the product space 33.

[0056] In addition, a protrusion or a concave is arranged on the end surface of the wedge-shaped block 34 facing the central axis, and a concave or a protrusion shape will also be formed on the product during injection molding. That is: the end surface of the wedge-shaped block 34 facing the central axis can also be called a molding surface 38. In this embodiment, the shape of the protrusion or the concave is the shape of identification characters for identifying the product name, so that the subsequent engraving process is no longer required.

[0057] During the process that the upper mold 100 approaches the lower mold 200 from top to bottom and is connected to the lower mold 200, the fourth template 4 in the upper mold 100 abuts against the first inclined surface 39 of the wedge-shaped block 34 and pushes the wedge-shaped block 34 to move towards the central axis side until the two wedge-shaped blocks 34 abut against each other. At this time, the upper mold 100 and the lower mold 200 are just connected. During the demolding process, due to the protrusion or the concave arranged on the molding surface 38, there will be interference between the wedge-shaped block 34 and the injection-molded product in the vertical direction. At this time, if the product is directly demolded in the vertical direction, it is easy to cause damage to the product.

[0058] In this embodiment, when demolding, the upper mold 100 is separated from the lower mold 200 upwards. Due to the arrangement of the first elastic member 35, the wedge-shaped block 34 will move away from the central axis side after being released from the restriction of the fourth template 4, so as to eliminate the interference of the wedge-shaped block 34 on the product in the vertical direction, thus facilitating the demolding and taking out of the product.

[0059] In a further setting, a moving member 15 and more than two clamping blocks 29 are installed in the upper mold 100. The clamping blocks 29 are circumferentially distributed with the rotation axis of the external thread body 21 as the center line, and all the clamping blocks 29 enclose a closed ring. The clamping blocks 29 are slidably connected to the upper mold 100 and a second elastic member 18 is connected between the clamping blocks 29 and the upper mold 100. The second elastic member 18 has an elastic tendency to drive the clamping blocks 29 to move away from the central axis, and the clamping blocks 29 abut against the side surface of the wedge block 34 facing the central axis. In this embodiment, a through space 17 is vertically and throughly opened in the fourth template 4 of the upper mold 100 for installing the clamping blocks 29. Two clamping blocks 29 are provided and are symmetrically distributed left and right. Both clamping blocks 29 are in a ring shape of 180°. When the two clamping blocks 29 are fitted together, they just form a closed circular ring. The left clamping block 29 abuts against the left wedge block 34, and the right clamping block 29 abuts against the right wedge block 34. The moving block is located inside the closed ring formed by the clamping blocks 29, and a second inclined surface 31 for contacting the clamping blocks 29 is provided on the side of the moving member 15. The second inclined surface 31 slopes outward from top to bottom. The lower end surface of the moving member 15 is located in the product space 33. The moving member 15 is slidably installed in the upper mold 100 in the vertical direction and a third elastic member 13 is connected between the moving member 15 and the upper mold 100. The third elastic member 13 has an elastic tendency to drive the moving member 15 to move upward. It should be noted that parts of the clamping blocks 29 and the moving member 15 are also located in the product space 33, that is to say, parts of the clamping blocks 29 and the moving member 15 serve as part of the side wall of the product space 33.

[0060] Specifically, an avoidance space 12 for avoiding the movement of the moving member 15 is opened in the third template 3. During the connection process of the upper mold 100 and the lower mold 200, the fourth template 4 in the upper mold 100 pushes the wedge block 34 to move, the wedge block 34 pushes the clamping block 29 to move, and the clamping block 29 pushes the moving member 15 to move. On the one hand, the fit between the wedge block 34 and the clamping block 29 and between the clamping block 29 and the moving block is ensured, that is, the sealing of the side wall of the product space 33 is ensured, and material leakage is avoided during the injection molding process of the product. On the other hand, when the upper mold 100 and the lower mold 200 are separated during the demolding process, the wedge block 34, the clamping block 29 and the moving block move under the action of the corresponding elastic members, so as to quickly separate from the product part 700 and avoid interfering with the product part 700 during demolding and causing damage to the product part 700.

[0061] The present application also provides a more preferred embodiment in terms of material injection.

[0062] Specifically, an injection port 500 is provided in the upper mold 100, and an internal channel 16 is provided in the moving part 15 so as to pass through the moving part 15 from top to bottom. The lower end of the internal channel 16 is connected to the product space 33, and the upper end of the internal channel 16 is connected to the injection port 500. In this embodiment, an injection port 500 is provided on the first template 1, and the raw material for injection molding flows from top to bottom into the internal channel 16 of the moving part 15, and then flows from the internal channel 16 into the product space 33, thereby ensuring the injection molding efficiency.

[0063] In a further configuration, since the moving member 15 may move up and down during use, a telescopic connecting tube 14 is connected between the upper end of the moving member 15 and the upper mold 100, and one end of the connecting tube 14 is connected to the injection port 500, and the other end is connected to the internal channel 16 to adapt to the up and down displacement of the moving member 15 and ensure the reliability of injection. Specifically, the connecting tube 14 is a bellows, which is cheap and low in cost, and the bellows is easy to cut to length, making it more convenient to use.

[0064] The present application also provides more preferred embodiments in terms of molding.

[0065] Specifically, the lower end of the moving member 15 abuts against the upper end of the inner thread body 28, so that the product space 33 is in a ring shape, and the final injection molded product 700 is also in a ring-shaped hollow shape, as shown in the attached Figure 7 , Attachment Figure 8 The product 700 has a surface 701 formed by the forming surface 38 of the wedge block 34 , an external thread surface 702 formed by the external thread body 21 , and an internal thread surface 703 formed by the internal thread body 28 .

[0066] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A double-layer thread twisting mechanism, characterized in that: include: An internal threaded body (28), wherein the upper end of the internal threaded body (28) has a thread for threading; An external twisted tooth body (21), the upper end of the external twisted tooth body (21) having a thread for twisting the teeth, the external twisted tooth body (21) being axially hollow, and the internal twisted tooth body (28) being located inside the external twisted tooth body (21) and being coaxially arranged with the external twisted tooth body (21); An inner support body (23), the inner support body (23) being fixedly disposed between the outer twisted tooth body (21) and the inner twisted tooth body (28); A first beryllium copper sleeve (22), the first beryllium copper sleeve (22) being fixedly connected to the inner side of the outer threaded body (21) and abutting against the inner support body (23); as well as A second beryllium copper sleeve (24), the second beryllium copper sleeve (24) is fixedly connected to the outside of the inner threaded body (28) and abuts against the inner support body (23).

2. A double-layer twisted tooth mold, characterized in that: The invention comprises an upper die (100), a lower die (200) and a double-layer twisted tooth mechanism (800) as claimed in claim 1, wherein the lower die (200) and the upper die (100) are detachably connected via a fastener (600); when the lower die (200) and the upper die (100) are connected, the lower die (200) and the upper die (100) enclose a product space (33); the upper ends of the inner twisted tooth body (28) and the outer twisted tooth body (21) are both located in the product space (33); the outer twisted tooth body (21) is rotatably mounted on the lower die (200); the lower end of the inner twisted tooth body (28) extends to the outside of the outer twisted tooth body (21) and is rotatably connected to the lower die (200); and the inner support body (23) is fixedly connected to the lower die (200).

3. The double-layer twisted tooth mold according to claim 2, characterized in that: The lower end of the outer threaded body (21) is fixedly connected to a first gear (26), the lower end of the inner threaded body (28) is fixedly provided with a second gear (27), and the lower die (200) is provided with a first opening (300) and a second opening (400), the first opening (300) being used for passing a rack capable of meshing with the first gear (26), and the second opening (400) being used for passing a rack capable of meshing with the second gear (27).

4. The double-layer twisted tooth mold according to claim 2, characterized in that: A ball retaining sleeve (25) is connected between the inner twisted tooth body (28) and the lower die (200), and a ball retaining sleeve (25) is connected between the outer twisted tooth body (21) and the lower die (200).

5. The double-layer twisted tooth mold according to any one of claims 2 to 4, characterized in that: The lower die (200) is slidably connected to two or more wedge blocks (34), the wedge blocks (34) are circumferentially distributed with the rotation axis of the external threaded tooth body (21) as the central axis and all the wedge blocks (34) form a closed ring, the wedge blocks (34) are slidably connected to the lower die (200) and a first elastic member (35) is connected between the wedge blocks (34) and the lower die (200), and the first elastic member (35) has an elastic tendency to drive the wedge blocks (34) to move away from the central axis; The side surface of the wedge block (34) facing the central axis is located in the product space (33) and has a protrusion or a concave portion, and the side surface of the wedge block (34) away from the central axis is a first inclined surface (39), which is inclined outward from top to bottom and abuts against the upper mold (100).

6. The double-layer twisted tooth mold according to claim 5, characterized in that: The upper die (100) is provided with a moving part (15) and more than two clamping blocks (29), the clamping blocks (29) are distributed circumferentially with the rotation axis of the external threaded body (21) as the center line and all the clamping blocks (29) form a closed ring, the clamping blocks (29) are slidably connected to the upper die (100) and a second elastic member (18) is connected between the clamping blocks (29) and the upper die (100), the second elastic member (18) having an elastic tendency to drive the clamping blocks (29) to move away from the central axis, and the clamping blocks (29) are in contact with a side surface of the wedge block (34) facing the central axis; The movable member (15) is located inside the closed ring formed by the clamping block (29), and the side of the movable member (15) has a second inclined surface (31) for contacting the clamping block (29), the second inclined surface (31) is inclined outward from top to bottom, the lower end surface of the movable member (15) is located in the product space (33), the movable member (15) is slidably installed in the upper mold (100) along the up-down direction, and a third elastic member (13) is connected between the movable member (15) and the upper mold (100), and the third elastic member (13) has an elastic tendency to drive the movable member (15) to move upward.

7. The double-layer twisted tooth mold according to claim 6, characterized in that: The upper mold (100) is provided with an injection port (500), and the movable member (15) is provided with an internal channel (16) which passes through the upper and lower parts, wherein the lower end of the internal channel (16) is connected to the product space (33) and the upper end of the internal channel (16) is connected to the injection port (500).

8. The double-layer twisted tooth mold according to claim 7, characterized in that: A telescopic connecting tube (14) is connected between the upper end of the moving member (15) and the upper mold (100); one end of the connecting tube (14) is connected to the injection port (500), and the other end is connected to the internal channel (16).

9. The double-layer twisted tooth mold according to claim 8, characterized in that: The connecting pipe (14) is a corrugated pipe.

10. The double-layer twisted tooth mold according to claim 6, characterized in that: The lower end of the moving member (15) abuts against the upper end of the inner threaded body (28).

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