Forming process of self-lubricating polytetrafluoroethylene sealing element and sealing structure design method

Abstract

The invention discloses a forming process of a self-lubricating teflon sealing element and a sealing structure design method, and relates to the technical field of teflon sealing elements, the forming process comprises the following operation steps: S1, raw material pretreatment: drying raw materials to remove moisture in the raw materials; s2, mixing: heating the raw materials to form a molten material; s3, molding: injecting materials in a swinging manner, and carrying out molding operation under a vacuum condition by using molding equipment; the forming equipment comprises a base, a lower die and an upper die are arranged above the base, and a forming cavity is formed in the top of the lower die; and a shaking control mechanism is arranged at the bottom of the lower die. According to the forming process of the self-lubricating polytetrafluoroethylene sealing element and the design method of the sealing structure, by arranging the air bag, the elastic adjusting mechanism and other structures, the effect that the lower mold and the upper mold swing up and down in a reciprocating mode is achieved, the interior of the forming cavity is rapidly and evenly filled with molten materials, the positions of the lower mold and the upper mold can be fixed, and the forming efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polytetrafluoroethylene seals, and in particular to a molding process and a sealing structure design method of a self-lubricating polytetrafluoroethylene seal. Background Art

[0002] PTFE sealing boxes are unique in the field of sealing materials for their excellent high-temperature sealing performance. Their unique material and structure enable them to maintain a stable sealing effect in high-temperature environments, making them a leader in high-temperature sealing materials, and self-lubricating PTFE seals are one of them.

[0003] In the prior art, during the molding process of self-lubricating polytetrafluoroethylene seals, after the molten material is injected into the molding cavity, the filling effect is usually achieved only by relying on the fluidity of the liquid, which is inefficient.

[0004] Therefore, it is necessary to propose a molding process and sealing structure design method of a self-lubricating PTFE seal to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a molding process and a sealing structure design method for a self-lubricating polytetrafluoroethylene seal, so as to solve the problem in the prior art that, during the molding process of the self-lubricating polytetrafluoroethylene seal, the molten material is injected into the molding cavity and the filling effect is usually achieved only by relying on the fluidity of the liquid, resulting in low efficiency.

[0006] To achieve the above object, the present invention provides the following technical solution: a molding process for a self-lubricating polytetrafluoroethylene seal, comprising the following steps:

[0007] S1. Raw material pretreatment: Dry the raw materials to remove moisture from them;

[0008] S2, mixing: heating the raw materials to form a molten material;

[0009] S3, molding: swing injection, and use molding equipment to perform molding operations under vacuum conditions;

[0010] The molding device includes a base, a lower mold and an upper mold are arranged above the base, and a molding chamber is arranged on the top of the lower mold;

[0011] The bottom of the lower mold is provided with a shaking control mechanism, which includes an airbag, and the expansion and contraction of the airbag drive the lower mold to swing;

[0012] An elastic adjustment mechanism is installed on the top of the upper mold, which includes a rubber pad, a magnetic block and an electromagnet. The rubber pad is fixedly connected to the top of the upper mold, and the magnetic block and the electromagnet are fixedly embedded in the inside of the rubber pad, and the magnetic block and the electromagnet are relatively distributed.

[0013] Preferably, the vibration control mechanism also includes a fixed box and a slide, the fixed box is fixedly connected to the top of the base, the slide is slidably arranged inside the fixed box, and the slide passes through the top of the fixed box, the lower mold is fixedly connected to the top of the slide, the airbag is arranged inside the fixed box, the bottom end of the airbag is fixedly connected to the bottom of the fixed box, and the top end of the airbag is fixedly connected to the slide.

[0014] Preferably, the airbag is connected to a first air pipe, and a first solenoid valve is installed on the first air pipe.

[0015] Preferably, a recovery chamber is opened inside the lower mold, and the recovery chamber is located below the molding chamber. The recovery chamber is connected to the molding chamber, and the top of the recovery chamber is connected to a third air pipe, and a third solenoid valve is installed on the third air pipe.

[0016] Preferably, a top ring is slidably provided inside the recovery chamber, a second electric push rod is installed inside the recovery chamber, and the top ring is fixedly connected to the telescopic end of the second electric push rod.

[0017] Preferably, an annular groove is provided on the top of the lower mold, and the annular groove surrounds the outside of the molding chamber. A sealing box is installed inside the annular groove, and the top end of the sealing box is open. The sealing box is connected to a second air pipe, and a second solenoid valve is installed on the second air pipe.

[0018] Preferably, a third electric push rod is fixedly connected to the top of the upper mold, a cross frame is fixedly connected to the telescopic end of the third electric push rod, an injection tube is fixedly connected to the cross frame, a fourth solenoid valve is installed on the injection tube, an injection groove is opened on the top of the upper mold, the bottom end of the injection groove is connected to the molding chamber, and the injection tube is connected and coordinated with the injection groove.

[0019] Preferably, the injection groove is in a truncated cone shape, and the inner diameter of the top of the injection groove is larger than the outer diameter of the injection tube.

[0020] Preferably, a bracket is fixedly connected to the base, a first electric push rod is fixedly connected to the lower surface of the top of the bracket, and the rubber pad is fixedly connected to the telescopic end of the first electric push rod.

[0021] The present invention also discloses a sealing structure design method for a self-lubricating polytetrafluoroethylene seal, which is applied to the molding process of the self-lubricating polytetrafluoroethylene seal, and further includes the following steps:

[0022] S1. Working condition analysis: Collect and analyze the operating environment parameters of the seal, such as working pressure, temperature, medium type, movement speed and working frequency, and determine the inner diameter, outer diameter and cross-sectional thickness parameters of the seal;

[0023] S2. Molding chamber optimization: Adapting the parameters of the seal.

[0024] Technical effects and advantages of the present invention:

[0025] 1. The present invention realizes the effect of reciprocating up and down swinging of the lower mold and the upper mold by providing structures such as air bags and elastic adjustment mechanisms, so that the molten material is quickly and evenly filled into the interior of the molding cavity, and the positions of the lower mold and the upper mold can be fixed, thereby improving molding efficiency;

[0026] 2. The back-and-forth movement of the injection pipe allows the molten material to quickly enter the molding chamber, avoiding blockage at the injection pipe;

[0027] 3. By setting up the recovery chamber, top ring and third air pipe and other structures, it is convenient to suck the interior of the molding chamber into a vacuum state to avoid the generation of bubbles, etc., and the seal can be pushed upward to assist demoulding;

[0028] 4. By providing a sealing box, a second air pipe and other structures, the upper mold and the lower mold are integrated, which improves the efficiency of sucking the interior of the molding chamber into a vacuum state. In addition, when the lower mold and the upper mold swing back and forth, the upper mold and the lower mold can be stably connected. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart of the molding process of the self-lubricating polytetrafluoroethylene seal of the present invention.

[0030] Figure 2 This is a structural schematic diagram of the molding equipment from one perspective of the present invention.

[0031] Figure 3 This is a structural schematic diagram of the molding equipment of the present invention from another perspective.

[0032] Figure 4 For the present invention Figure 3 A magnified schematic diagram of the structure in the middle.

[0033] Figure 5 For the present invention Figure 3 A magnified schematic diagram of the structure at point B in the middle.

[0034] In the figure: 1. base; 2. fixing box; 3. slide; 4. airbag; 5. first air pipe; 6. first solenoid valve; 7. lower mold; 8. upper mold; 9. rubber pad; 10. magnetic block; 11. electromagnet; 12. ring groove; 13. sealing box; 14. second air pipe; 15. second solenoid valve; 16. molding chamber; 17. bracket; 18. recovery chamber; 19. top ring; 20. first electric push rod; 21. second electric push rod; 22. third air pipe; 23. third solenoid valve; 24. third electric push rod; 25. cross frame; 26. injection pipe; 27. fourth solenoid valve; 28. injection trough. DETAILED DESCRIPTION

[0035] The present invention provides Figures 1 to 5 The molding process of a self-lubricating PTFE seal shown in the figure includes the following steps:

[0036] S1. Raw material pretreatment: Dry the raw materials to remove moisture from them;

[0037] S2, mixing: heating the raw materials to form a molten material;

[0038] S3, molding: swing injection, and use molding equipment to perform molding operations under vacuum conditions;

[0039] In specific settings, the molding equipment includes a base 1, a lower mold 7 and an upper mold 8 are arranged above the base 1, a molding chamber 16 is provided on the top of the lower mold 7, which is used for the molding operation of the polytetrafluoroethylene seal, and an injection groove 28 is opened on the top of the upper mold 8. The bottom end of the injection groove 28 is connected to the molding chamber 16. When the upper mold 8 moves downward and fits with the lower mold 7, the molten material is injected into the interior of the molding chamber 16 through the injection groove 28.

[0040] In order to improve the efficiency of injecting molten material into the interior of the molding chamber 16, a third electric push rod 24 is fixedly connected to the top of the upper mold 8, and a cross frame 25 is fixedly connected to the telescopic end of the third electric push rod 24, and an injection pipe 26 is fixedly connected to the cross frame 25. The injection pipe 26 is connected to the factory's molten material conveying pipeline; a fourth solenoid valve 27 is installed on the injection pipe 26, and the injection pipe 26 is connected and coordinated with the injection groove 28. The injection groove 28 is frustum-shaped, and the inner diameter of the top of the injection groove 28 is larger than the outer diameter of the injection pipe 26.

[0041] Specifically, the telescopic end of the third electric push rod 24 is controlled to switch between extension and retraction, thereby driving the injection tube 26 to move back and forth through the cross frame 25, and in this process the cross frame 25 covers the top of the injection slot 28. The injection slot 28 is only connected to the injection tube 26 and is not connected to the external atmospheric environment. The back and forth movement of the injection tube 26 allows the molten material to quickly enter the interior of the molding chamber 16, avoiding blockage at the injection tube 26.

[0042] During the above process, the bottom end of the injection pipe 26 always corresponds to the injection groove 28 to ensure stable feeding.

[0043] A vibration control mechanism is provided at the bottom of the lower mold 7, comprising an airbag 4. The vibration control mechanism also includes a fixed box 2 and a slide 3. The fixed box 2 is fixedly connected to the top of the base 1. The slide 3 is slidably disposed within the fixed box 2 and extends through the top of the fixed box 2. The lower mold 7 is fixedly connected to the top of the slide 3. The airbag 4 is disposed within the fixed box 2, with its bottom end fixedly connected to the bottom of the fixed box 2 and its top end fixedly connected to the slide 3.

[0044] The airbag 4 is connected to a first air pipe 5, on which a first solenoid valve 6 is installed. The first air pipe 5 is connected to the factory's gas control pipeline, and the first air pipe 5 can be used to inflate the airbag 4 and also to suck the gas inside the airbag 4.

[0045] During actual use, the first solenoid valve 6 is opened, and the first air pipe 5 is used to inflate the airbag 4. The airbag 4 expands and becomes larger, and the slide 3 and the lower mold 7 can move upward; when the first air pipe 5 sucks the gas inside the airbag 4, the airbag 4 contracts and becomes smaller, and the slide 3 and the lower mold 7 can move downward.

[0046] An elastic adjustment mechanism is installed on the top of the upper mold 8, which includes a rubber pad 9, a magnetic block 10 and an electromagnet 11. The rubber pad 9 is fixedly connected to the top of the upper mold 8, and the magnetic block 10 and the electromagnet 11 are fixedly embedded in the inside of the rubber pad 9. The magnetic block 10 and the electromagnet 11 are relatively distributed.

[0047] A bracket 17 is fixedly connected to the base 1 , a first electric push rod 20 is fixedly connected to the lower surface of the top of the bracket 17 , and a rubber pad 9 is fixedly connected to the telescopic end of the first electric push rod 20 .

[0048] When the electromagnet 11 is turned on, the magnetism of the electromagnet 11 and the magnetic block 10 on the side close to each other is controlled to be the same. Under the action of the repulsive force, the rubber pad 9 cannot be elastically deformed; when the electromagnet 11 is turned off, the repulsive force is lost and the rubber pad 9 can be elastically deformed.

[0049] Specifically, the telescopic end of the first electric push rod 20 is controlled to extend, driving the upper mold 8 to move downward to fit with the lower mold 7 , and the molten material is injected into the molding chamber 16 through the injection pipe 26 and the injection groove 28 .

[0050] Furthermore, the electromagnet 11 is closed so that the rubber pad 9 can be elastically deformed, and the first solenoid valve 6 is opened. The first air pipe 5 inflates the air into the airbag 4, the airbag 4 expands and becomes larger, and the slide 3, the lower mold 7, and the upper mold 8 move upward; the first air pipe 5 sucks the gas inside the airbag 4, the airbag 4 shrinks and becomes smaller, and the slide 3, the lower mold 7, and the upper mold 8 move downward. The operation is repeated many times, so that the lower mold 7 and the upper mold 8 produce an effect of reciprocating up and down swinging.

[0051] After a certain period of time, the first air pipe 5 inflates the air bag 4 to push the slide 3, the lower mold 7, and the upper mold 8 to move upward until they can no longer move, and then the first solenoid valve 6 is closed; at the same time, the electromagnet 11 is started to control the magnetism of the electromagnet 11 and the magnetic block 10 on the side close to each other to be of the same polarity. Under the action of the repulsive force, the rubber pad 9 cannot be elastically deformed, thereby fixing the position of the lower mold 7 and the upper mold 8 to ensure the stability of the cooling molding.

[0052] The present invention realizes the effect of reciprocating up and down swinging of the lower mold 7 and the upper mold 8 by providing structures such as the airbag 4 and the elastic adjustment mechanism, so that the molten material is quickly and evenly filled into the interior of the molding cavity 16, and the positions of the lower mold 7 and the upper mold 8 can be fixed to improve the molding efficiency.

[0053] In order to improve the quality of molding and avoid the generation of bubbles, a recovery chamber 18 is opened inside the lower mold 7. The recovery chamber 18 is located below the molding chamber 16. The recovery chamber 18 is connected to the molding chamber 16. The top of the recovery chamber 18 is connected to the third air pipe 22. A third solenoid valve 23 is installed on the third air pipe 22, and the third air pipe 22 is connected to the gas control pipeline of the factory.

[0054] A top ring 19 is slidably provided inside the recovery chamber 18 . A second electric push rod 21 is installed inside the recovery chamber 18 . The top ring 19 is fixedly connected to the telescopic end of the second electric push rod 21 .

[0055] During the molding operation, after the upper mold 8 moves downward and fits with the lower mold 7, the telescopic end of the second electric push rod 21 is controlled to be retracted, driving the top ring 19 to move downward, so that the third air pipe 22 can be connected with the molding chamber 16 through the top of the recovery chamber 18. At this time, the fourth solenoid valve 27 on the injection pipe 26 is in a closed state, and the inside of the molding chamber 16 is sucked to a vacuum state by the third air pipe 22, and then the third solenoid valve 23 is closed; then the telescopic end of the second electric push rod 21 is controlled to extend, driving the top ring 19 to move upward, and the top of the top ring 19 is flush with the bottom end of the molding chamber 16.

[0056] After the seal is cooled and formed, the telescopic end of the first electric push rod 20 is controlled to extend to separate the upper mold 8 from the lower mold 7; then the telescopic end of the second electric push rod 21 is controlled to extend to drive the top ring 19 to move upward, push the seal upward, and assist in demolding.

[0057] By providing structures such as the recovery chamber 18, the top ring 19 and the third air pipe 22, it is convenient to suck the interior of the molding chamber 16 into a vacuum state to avoid the generation of bubbles, etc., and the sealing member can be pushed upward to assist demoulding.

[0058] In order to improve the efficiency of sucking the inside of the molding chamber 16 to a vacuum state, an annular groove 12 is opened on the top of the lower mold 7. The annular groove 12 surrounds the outside of the molding chamber 16. A sealing box 13 is installed inside the annular groove 12, and the top end of the sealing box 13 is open. The sealing box 13 can be made of but is not limited to rubber material. A second air pipe 14 is connected to the sealing box 13, and a second solenoid valve 15 is installed on the second air pipe 14. The second air pipe 14 is connected to the gas control pipeline of the factory.

[0059] A rubber block can be provided at the bottom of the upper mold 8 to cooperate with the sealing box 13 to ensure sealing, which can be adjusted according to specific usage conditions.

[0060] Specifically, when the upper mold 8 moves downward and fits into the lower mold 7, the top of the sealing box 13 fits into the bottom of the upper mold 8, the second solenoid valve 15 is opened, and the second air pipe 14 sucks the gas inside the sealing box 13, and then the second solenoid valve 15 is closed to complete the adsorption and fixation of the upper mold 8, so that the upper mold 8 and the lower mold 7 form a whole, thereby improving the efficiency of sucking the inside of the molding chamber 16 to a vacuum state. In addition, when the lower mold 7 and the upper mold 8 swing back and forth up and down, the upper mold 8 and the lower mold 7 can be stably connected.

[0061] The present invention also discloses a sealing structure design method for a self-lubricating polytetrafluoroethylene seal, which is applied to the molding process of the self-lubricating polytetrafluoroethylene seal, and further includes the following steps:

[0062] S1. Working condition analysis: Collect and analyze the operating environment parameters of the seal, such as working pressure, temperature, medium type, movement speed and working frequency, and determine the inner diameter, outer diameter and cross-sectional thickness parameters of the seal;

[0063] S2. Optimization of the molding chamber 16: Adapting the parameters of the seal.

Claims

1. A molding process for a self-lubricating polytetrafluoroethylene seal, characterized by: The following steps are included: S1. Raw material pretreatment: Dry the raw materials to remove moisture from them; S2, mixing: heating the raw materials to form a molten material; S3, molding: swing injection, and use molding equipment to perform molding operations under vacuum conditions; The molding device comprises a base (1), a lower mold (7) and an upper mold (8) are arranged above the base (1), and a molding chamber (16) is arranged on the top of the lower mold (7); The bottom of the lower mold (7) is provided with a shaking control mechanism, which includes an air bag (4). The expansion and contraction of the air bag (4) drives the lower mold (7) to swing; An elastic adjustment mechanism is installed on the top of the upper mold (8), and the elastic adjustment mechanism includes a rubber pad (9), a magnetic block (10) and an electromagnet (11). The rubber pad (9) is fixedly connected to the top of the upper mold (8), and the magnetic block (10) and the electromagnet (11) are fixedly embedded in the inside of the rubber pad (9), and the magnetic block (10) and the electromagnet (11) are relatively distributed.

2. The molding process of a self-lubricating polytetrafluoroethylene seal according to claim 1, characterized in that: The vibration control mechanism also includes a fixed box (2) and a slide (3), wherein the fixed box (2) is fixedly connected to the top of the base (1), the slide (3) is slidably arranged inside the fixed box (2), and the slide (3) passes through the top of the fixed box (2), the lower mold (7) is fixedly connected to the top of the slide (3), the airbag (4) is arranged inside the fixed box (2), the bottom end of the airbag (4) is fixedly connected to the bottom of the fixed box (2), and the top end of the airbag (4) is fixedly connected to the slide (3).

3. The molding process of a self-lubricating polytetrafluoroethylene seal according to claim 1, characterized in that: The air bag (4) is connected to a first air pipe (5), and a first electromagnetic valve (6) is installed on the first air pipe (5).

4. The molding process of a self-lubricating polytetrafluoroethylene seal according to claim 1, characterized in that: A recovery chamber (18) is provided inside the lower mold (7), and the recovery chamber (18) is located below the molding chamber (16). The recovery chamber (18) is connected to the molding chamber (16), and the top end of the recovery chamber (18) is connected to a third air pipe (22), and a third solenoid valve (23) is installed on the third air pipe (22).

5. The molding process of a self-lubricating polytetrafluoroethylene seal according to claim 4, characterized in that: A top ring (19) is slidably provided inside the recovery chamber (18), a second electric push rod (21) is installed inside the recovery chamber (18), and the top ring (19) is fixedly connected to the telescopic end of the second electric push rod (21).

6. The molding process of a self-lubricating polytetrafluoroethylene seal according to claim 1, characterized in that: The top of the lower mold (7) is provided with an annular groove (12), which surrounds the outer side of the molding chamber (16). A sealing box (13) is installed inside the annular groove (12), and the top end of the sealing box (13) is open. The sealing box (13) is connected to a second air pipe (14), and a second solenoid valve (15) is installed on the second air pipe (14).

7. The molding process of a self-lubricating polytetrafluoroethylene seal according to claim 1, characterized in that: The top of the upper mold (8) is fixedly connected to a third electric push rod (24), the telescopic end of the third electric push rod (24) is fixedly connected to a cross frame (25), the cross frame (25) is fixedly connected to an injection pipe (26), the injection pipe (26) is installed with a fourth solenoid valve (27), the top of the upper mold (8) is provided with an injection groove (28), the bottom end of the injection groove (28) is connected to the molding chamber (16), and the injection pipe (26) is connected and matched with the injection groove (28).

8. The molding process of a self-lubricating polytetrafluoroethylene seal according to claim 7, characterized in that: The injection groove (28) is in a truncated cone shape, and the inner diameter of the top end of the injection groove (28) is larger than the outer diameter of the injection tube (26).

9. The molding process of a self-lubricating polytetrafluoroethylene seal according to claim 1, characterized in that: A bracket (17) is fixedly connected to the base (1), a first electric push rod (20) is fixedly connected to the lower surface of the top of the bracket (17), and the rubber pad (9) is fixedly connected to the telescopic end of the first electric push rod (20).

10. A method for designing a sealing structure of a self-lubricating polytetrafluoroethylene seal, characterized in that: The molding process for the self-lubricating polytetrafluoroethylene seal according to any one of claims 1 to 9 further comprises the following steps: S1. Working condition analysis: Collect and analyze the operating environment parameters of the seal, such as working pressure, temperature, medium type, movement speed and working frequency, and determine the inner diameter, outer diameter and cross-sectional thickness parameters of the seal; S2. Optimization of the molding chamber (16): Adapting the parameters of the seal.

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