Forming and vulcanizing method for airtight ring with large composite metal framework structure

Abstract

The invention relates to the technical field of spaceflight matching rubber products, in particular to a large composite metal framework structure airtight ring forming vulcanization method which comprises the steps of rubber material extrusion, blank shaping, polytetrafluoroethylene film fitting, metal framework die filling, vulcanization trimming and the like, and a split die, a positioning pin and a cone matching structure are combined. The problems of metal framework positioning, size precision control and vulcanization defects of the oversized airtight ring are solved. The core innovation is as follows: a dovetail groove is adopted to limit the circumferential displacement of the split die, so that the uniform distribution precision of 64 skeleton pieces is ensured; the vulcanization process is optimized through step boosting and multiple exhaust, and internal bubbles are eliminated; and the polytetrafluoroethylene film is subjected to vacuum lamination by taking the parting line as a reference. The method improves the qualified rate of products, is suitable for efficient production of airtight rings with the diameter larger than 2 m, and provides key technical support for reliability of aerospace equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of aerospace supporting rubber products, specifically to a forming and vulcanizing method for a large composite metal skeleton structure airtight ring. Background Technique

[0002] The large uniformly distributed metal skeleton composite airtight ring is a sealing and shock-absorbing product used on large launchers. The outer wall of the airtight ring is fixed to the inner wall of the device, and the inner wall and lip of the airtight ring play a role in sealing and shock absorption during the launch process. The airtight ring is composed of a stainless steel arc-shaped metal skeleton, a rubber body, and a polytetrafluoroethylene film. A polytetrafluoroethylene film is pasted at the inner diameter lip part. A 64-piece stainless steel arc-shaped metal plate skeleton reinforcement structure is evenly distributed in the airtight ring. Since the lip contacts the outer wall of the launch device, there are two cable covers at two relative positions on the outer wall of the launch device, so that the inner diameter of the seal ring lip needs to be increased at the corresponding positions of the cable covers to avoid the cable covers. The airtight ring is soaked in seawater for a long time and under long-term load during use; therefore, its use requirements are more stringent, the storage life requirement is longer, the number of uses is up to 20 - 30 times, and it withstands complex working conditions such as positive and negative pressure changes, friction, and collision, so the quality and technical requirements of this product are relatively strict.

[0003] The inner and outer diameters of this composite rubber product both exceed 2 meters, but its dimensional tolerance requirements are highly precise, and it is difficult to guarantee the die pressing dimensional accuracy; the number of metal skeleton parts is large, and the positioning accuracy requirements are high. Incorrect positions of the skeleton parts will cause the entire airtight ring to be unable to be installed, and improper die splitting will cause the product to be unable to be demolded; the existing methods cannot balance dimensional accuracy and production efficiency, resulting in a low product qualification rate and serious material waste. Summary of the Invention

[0004] The purpose of the present invention is to provide a forming and vulcanizing method for a large composite metal skeleton structure airtight ring to solve the problems raised in the above background technique.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A forming and vulcanizing method for a large composite metal skeleton structure airtight ring includes the following steps:

[0007] Extrusion of rubber compound: Extruding the kneaded rubber compound through a special extrusion die to form a lip-shaped semi-finished rubber compound.

[0008] Semi-finished blank sizing: Using a sizing die to close the die and size the blank, discharging the excess rubber compound. The sizing die includes an upper sizing die part, a lower sizing die part, a sizing split die, and an outer sleeve.

[0009] Polytetrafluoroethylene film lamination: Applying an adhesive to the lip of the sized blank, laminating the cut-to-size polytetrafluoroethylene film to the specified position, and eliminating air bubbles by scraping and pressing.

[0010] Loading the metal skeleton parts into the mold: Load the 64 coated metal skeleton parts into the positioning area of the lower split cavity of the vulcanization mold in sequence, and use the conical fit of the lower outer sleeve to achieve split circular closing;

[0011] Product vulcanization: Place the assembled vulcanization mold in a large flat vulcanizing machine, apply vulcanization pressure and temperature after multiple pressings and exhaustings. The vulcanization mold includes an upper split, an upper outer sleeve, a lower split, a lower outer sleeve, and a vulcanization split mold;

[0012] Trimming treatment: After vulcanization, remove the rubber edges to obtain the finished airtight ring rubber body.

[0013] Furthermore, in the step of extruding the rubber compound, the extrusion amount of the rubber compound is accurately controlled by calculating the volume of the cavity of the sizing mold to ensure that the lip structure of the semi-finished rubber compound is consistent with the designed dimensions.

[0014] Furthermore, the assembly of the sizing mold includes the following operations:

[0015] Fix the lower die core to the lower die through a positioning pin to limit the circumferential movement of the lower die core. The lower die core and the lower die are fixed through a cylindrical fit to ensure the circumferential position fixation of the wall of the lip of the airtight ring and the metal skeleton;

[0016] Fill the lip-shaped semi-finished rubber compound into the lip cavity of the lower die core;

[0017] Install the upper die core, sizing split mold, and outer sleeve in sequence, and achieve split mold closing and cavity circular closing through conical fit.

[0018] Furthermore, when laminating the polytetrafluoroethylene film, its starting end is aligned with the parting line of the blank, and during the lamination process, vacuum adsorption or manual scraping is used to remove the air bubbles between the film and the rubber body.

[0019] Furthermore, when loading the metal skeleton parts into the mold, use a copper hammer to knock the 64 metal skeleton parts into the lower split cavity one by one to ensure that the inner side of its arc is in close contact with the outer side of the airtight ring blank, and achieve radial positioning through the conical fit of the vulcanization split mold and the upper outer sleeve.

[0020] Furthermore, a dovetail groove fit structure is provided between the lower split of the vulcanization mold and the lower die to limit the circumferential displacement of the lower split and at the same time ensure the circumferential position fixation of the wall of the lip of the airtight ring and the metal skeleton parts.

[0021] The beneficial effects of the present invention:

[0022] 1. The present invention adopts a vulcanization method of rubber compound extrusion + shaping + vulcanization, and performs pre-shaping and then film laminating on the product, which is beneficial to exhaust gas during the vulcanization process of the product, ensures the fitting accuracy of the polytetrafluoroethylene film, avoids the phenomena of product deformation, lack of glue, and generation of air bubbles, improves the density and strength of the rubber product, and enhances the comprehensive performance of the airtight ring.

[0023] 2. The vulcanization method of rubber compound extrusion + shaping + vulcanization adopted by the present invention can accurately control the shape and size of the airtight ring product, ensure that the product meets the design requirements, and can also guarantee a high dimensional tolerance accuracy even when the inner and outer diameters both exceed two meters.

[0024] 3. The present invention realizes the mechanical positioning of 64 metal framework parts through the conical fitting and assembly method of the upper and lower split dies and the upper and lower outer sleeves, prevents the phenomenon of position deviation due to rubber flow during the vulcanization process, and is also beneficial to the mold loading and unloading of the product.

[0025] 4. A dovetail groove fitting point is arranged between the lower split die and the lower mold of the present invention, which restricts the rotation of the lower split die in the circumferential direction and ensures the relative position in the circumferential direction between the metal framework part and the lip avoidance of the airtight ring.

[0026] 5. Through a perfect process route and precise mold design, the present invention controls the waste of rubber materials at a low level, improves the material utilization rate, the surface of the molded rubber product is smooth and flat, the appearance quality is good, and the subsequent processing procedures are reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings;

[0028] Figure 1 is a cross-sectional schematic diagram of the product of the present invention;

[0029] Figure 2 is a schematic diagram of the shaping mold of the present invention;

[0030] Figure 3 is a schematic diagram of the vulcanization mold of the present invention;

[0031] Figure 4 is a three-dimensional schematic diagram of the product of the present invention;

[0032] Among them, the reference numerals are as follows:

[0033] 1 - Airtight ring rubber body, 2 - Metal skeleton part, 3 - Back rubber sheet, 4 - Polytetrafluoroethylene film, 5 - Upper die core, 6 - Upper die, 7 - Upper sizing die part, 8 - Sizing split die, 9 - Outer sleeve, 10 - Lower die, 11 - Lower sizing die part, 12 - Airtight ring blank, 13 - Positioning pin, 14 - Lower die core, 15 - Upper split part, 16 - Upper outer sleeve, 17 - Lower outer sleeve, 18 - Lower split part. Detailed implementation method

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] Embodiment:

[0036] Please refer to Figures 1 to 3 , in the embodiment of the present invention, a method for forming and vulcanizing an airtight ring with a large composite metal skeleton structure includes the following steps:

[0037] Rubber compound extrusion: Extrude the mixed rubber through a special extrusion die orifice to form a lip-shaped semi-finished rubber compound 12;

[0038] Semi-finished blank sizing: Use a sizing mold to close the mold and size the blank, discharging the excess rubber compound. The sizing mold includes an upper sizing die part 7, a lower sizing die part 11, a sizing split die 8, and an outer sleeve 9;

[0039] Polytetrafluoroethylene film 4 fitting: Apply an adhesive to the lip of the sized blank, fit the cut-to-size polytetrafluoroethylene film 4 to the designated position, and eliminate air bubbles by scraping and pressing;

[0040] Installation of metal skeleton part 2 into the mold: Sequentially install 64 coated metal skeleton parts 2 into the cavity positioning area of the lower split part 18 of the vulcanization mold, and use the conical fit of the lower outer sleeve 17 to achieve split circular closing;

[0041] Product vulcanization: Place the assembled vulcanization mold in a large flat vulcanizer, apply vulcanization pressure and temperature after multiple pressings and exhaustings. The vulcanization mold includes an upper split part 15, an upper outer sleeve 16, a lower split part 18, a lower outer sleeve 17, and a vulcanization split die;

[0042] Trimming treatment: After vulcanization, remove the rubber edges to obtain the finished airtight ring rubber body 1.

[0043] Among them, in the rubber compound extrusion step, the extrusion amount of the rubber compound is accurately controlled by calculating the volume of the sizing mold cavity to ensure that the lip structure of the semi-finished rubber compound 12 is consistent with the design dimensions.

[0044] Among them, the assembly of the shaping mold includes the following operations:

[0045] Fix the lower die core 14 to the lower die 10 through the positioning pin 13 to limit the circumferential movement of the lower die core 14. The lower die core 14 and the lower die are fixed through a cylindrical fit to ensure the circumferential position fixation of the wall of the airtight ring lip and the metal skeleton;

[0046] Fill the lip-shaped semi-finished rubber compound 12 into the lip cavity of the lower die core 14;

[0047] Install the upper die core 5, the shaping split die 8, and the outer sleeve 9 in sequence, and achieve split die closing and cavity rounding through a conical fit.

[0048] Among them, when the polytetrafluoroethylene film 4 is adhered, its starting end is aligned with the parting line of the blank. During the adhesion process, the air bubbles between the film and the rubber body are removed by means of vacuum adsorption or manual scraping.

[0049] Among them, when the metal skeleton parts 2 are installed in the mold, use a copper hammer to knock 64 metal skeleton parts 2 into the cavity of the lower split die 18 one by one, ensure that the inner side of its arc is in close contact with the outer side of the airtight ring blank 12, and achieve radial positioning through the conical fit of the vulcanization split die and the upper outer sleeve 16.

[0050] Among them, a dovetail groove fit structure is provided between the lower split die 18 of the vulcanization mold and the lower die 10 to limit the circumferential displacement of the lower split die 18, and at the same time ensure the circumferential position fixation of the wall position of the airtight ring lip and the metal skeleton parts 2.

[0051] Specifically:

[0052] Rubber compound extrusion: Add the mixed rubber compound to the rubber extruder, install a special extrusion die, extrude the lip-shaped semi-finished rubber compound 12, and the extrusion amount is accurately calculated according to the cavity volume of the shaping mold;

[0053] Blank shaping:

[0054] Fix the lower die core 14 to the lower die 10 through the positioning pin 13, load the lip-shaped rubber compound 12, and make the lower edge of its lip closely adhere to the cavity of the lower die core 14;

[0055] Install the upper die core 5, and its lip presses the upper edge of the rubber compound;

[0056] Install the shaping split die 8 and the outer sleeve 9 in sequence, and make the shaping split die 8 radially contract through a conical fit, round the cavity and extrude the surplus material;

[0057] After closing the mold, send it to a flat vulcanizing machine for exhaust;

[0058] Adhesion of the polytetrafluoroethylene film 4:

[0059] Apply epoxy adhesive to the lower surface of the lip of the preform 12, and cut the polytetrafluoroethylene film 4 to a fixed length;

[0060] With the parting line as the reference, fit the film, and use a vacuum adsorption device to remove the interface bubbles;

[0061] Install the metal skeleton into the mold:

[0062] Install the film-laminated preform 12 into the lower mold 10 of the vulcanization mold, install 16 lower segments 18 according to the cavity positions of the lower segments 18, and use the conical fit of the lower outer sleeve 17 to make it round;

[0063] Use a copper hammer to knock 64 coated metal skeleton parts 2 into the positioning grooves of the lower segments 18 in sequence, ensuring that the inner side is closely attached to the preform 12;

[0064] Wrap a fixed-length rubber film 3 around the outside of the skeleton, and install the upper segment 15 and the upper outer sleeve 16;

[0065] Vulcanization treatment:

[0066] Place the whole mold on a flat vulcanizing machine, and carry out vulcanization after multiple exhaust operations;

[0067] Trimming and inspection:

[0068] After vulcanization, the product is mechanically cut to remove the rubber edges.

[0069] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed.

Claims

1. A method for forming and vulcanizing an airtight ring of a large composite metal skeleton structure, characterized in that It includes the following steps: Rubber compound extrusion: Extrude the kneaded rubber compound through a special extrusion die to form a lip-shaped semi-finished rubber compound (12); Semi-finished blank shaping: Use a shaping die to close and shape the blank, and discharge the excess rubber compound. The shaping die includes an upper shaping die part (7), a lower shaping die part (11), a shaping split die (8) and an outer sleeve (9); Polytetrafluoroethylene film (4) bonding: Apply an adhesive to the lip of the shaped blank, bond the polytetrafluoroethylene film (4) cut to a specified length to the specified position, and eliminate air bubbles by scraping and pressing; Metal skeleton part (2) mold loading: Sequentially load 64 coated metal skeleton parts (2) into the cavity positioning area of the lower split (18) of the vulcanization mold, and use the conical fit of the lower outer sleeve (17) to achieve split circle combination; Product vulcanization: Place the assembled vulcanization mold in a large flat vulcanizer, apply vulcanization pressure and temperature after multiple pressings and exhaustings. The vulcanization mold includes an upper split (15), an upper outer sleeve (16), a lower split (18), a lower outer sleeve (17) and a vulcanization split die; Trimming treatment: After vulcanization, remove the rubber edges to obtain the finished airtight ring rubber body (1).

2. The airtight ring forming and vulcanizing method for the large composite metal skeleton structure according to claim 1, characterized in that, In the rubber compound extrusion step, accurately control the rubber compound extrusion amount by calculating the volume of the shaping die cavity to ensure that the lip structure of the semi-finished rubber compound (12) is consistent with the design dimensions.

3. The airtight ring forming and vulcanizing method for the large composite metal skeleton structure according to claim 1, characterized in that, The assembly of the shaping die includes the following operations: Fix the lower die core (14) to the lower die (10) through a positioning pin (13), limit the circumferential movement of the lower die core (14) through the positioning pin (13), and fix the lower die core (14) and the lower die through a cylindrical fit to ensure the circumferential position fixation of the wall of the airtight ring lip and the metal skeleton; Fill the lip-shaped semi-finished rubber compound (12) into the lip cavity of the lower die core (14); Sequentially install the upper die core (5), the shaping split die (8), and the outer sleeve (9), and achieve split die closing and cavity rounding through conical fit.

4. The airtight ring forming and vulcanizing method for the large composite metal skeleton structure according to claim 1, characterized in that, When the polytetrafluoroethylene film (4) is bonded, its starting end is aligned with the parting line of the blank, and air bubbles between the film and the rubber body are removed by vacuum adsorption or manual scraping during the bonding process.

5. The airtight ring forming and vulcanizing method for the large composite metal skeleton structure according to claim 1, characterized in that, When the metal skeleton part (2) is loaded into the mold, use a copper hammer to knock 64 metal skeleton parts (2) into the cavity of the lower split (18) one by one to ensure that the inner arc is in close contact with the outer side of the airtight ring blank (12), and achieve radial positioning through the conical fit of the vulcanization split die and the upper outer sleeve (16).

6. The airtight ring forming and vulcanizing method for the large composite metal skeleton structure according to claim 1, characterized in that, A dovetail groove fit structure is provided between the lower split (18) and the lower die (10) of the vulcanization mold to limit the circumferential displacement of the lower split (18), and at the same time ensure the circumferential position fixation of the wall of the airtight ring lip and the metal skeleton part (2).

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