Heat insulation layer-front and rear connector assembly and integrated forming method

Abstract

The invention provides a heat insulation layer-front and rear connector assembly and an integrated forming method. The heat insulation layer-front and rear connector assembly comprises a heat insulation layer, a front connector is arranged on the front portion of the heat insulation layer, and a rear connector is arranged on the rear portion of the heat insulation layer; the heat insulation layer is prepared from the following raw materials: base rubber, reinforcing filler, ablation-resistant filler, low-density filler, chopped fibers, a coupling agent and a rubber curing agent. In the integrated forming mold, a core mold is coaxially and detachably mounted in a left half mold and a right half mold; a slit cavity among the left half mold, the right half mold and the core mold is a heat insulation layer molded surface cavity; a front joint clamping groove and a rear joint clamping groove are also formed in the left half mold and the right half mold outside the molded surface cavity of the heat insulation layer; a front joint sleeving part and a rear joint sleeving part are further arranged on the core mold; according to the method, the problems that in the prior art, the heat insulation layer, the front connector, the rear connector and other parts need to be manufactured step by step, and due to manual bonding, procedures are complex, efficiency is low, and quality consistency is poor are effectively solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid rocket engines, and relates to an insulation layer-front and rear joint assembly for a composite shell with a large opening, and specifically relates to an insulation layer-front and rear joint assembly for a composite shell of a solid engine and an integrated molding method. Background Art

[0002] The composite combustion chamber shell (hereinafter referred to as the composite shell) prepared by the carbon fiber winding process is the main component of the new high-thrust solid rocket engine. It is a carrier for containing solid propellants, and plays the role of maintaining pressure, bearing pressure, and limiting the combustion surface during the working process of the propellant. Among them, the insulation layer is built into the inner wall of the combustion chamber shell, which supports and cushions the charge. During the working process of the propellant, the insulation layer plays a role in protecting the structural integrity of the engine. In order to ensure the reliable operation of the solid rocket engine, the insulation layer must have the following characteristics: good mechanical properties and ablation resistance, so as to support and cushion the charge, and resist the scouring and ablation of high-temperature, high-speed combustion gas and particles. At the same time, the front and rear ends of the composite shell are usually provided with structures such as front joints and rear joints, which need to be firmly bonded to the insulation layer and the composite shell to form an integral structure.

[0003] At present, the front and rear joints of the composite shell are usually made by laying the insulation layer green sheet on the surface of the core mold, and then using an adhesive to bond it to the surface of the insulation layer, and then wrapping the front and rear joints between the composite material and the insulation layer through the carbon fiber winding and curing process. The Chinese patent with application number CN201510888925.9 proposes a method for preparing the insulation layer of the head first by separate molding and then pasting it on the surface of the core mold. This method can realize the controllable manufacturing of the insulation layer in the head area of ​​the large-size insulation layer product, but there are many manufacturing processes. The Chinese patent with application number CN201610457390.4 proposes a method for preparing a rocket composite shell, which sequentially prepares the core mold, the inner insulation layer and the fiber shell, and each component is sequentially bonded to form a whole. The Chinese patent with application number CN201910356581.5 proposes a method for integrated molding of a composite material pipe body and a connector, which requires the connector to be plugged into the composite material and the end face of the core mold during the carbon fiber winding process, and then continue to wind. This patent has some implications for the present invention, but does not involve the process related to the thermal insulation layer. It can be seen that there is no method in the existing patents that can realize the integrated molding of the thermal insulation layer and the front and rear joints in the composite shell of the solid rocket engine. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide an insulation layer-front and rear joint assembly and an integrated molding method to solve the technical problems in the prior art that the insulation layer and the front and rear joints need to be prepared through multiple steps and manually bonded, resulting in low efficiency and poor quality reliability.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0006] A heat insulating layer-front and rear joint assembly comprises a heat insulating layer, a front joint is arranged at the front of the heat insulating layer, and a rear joint is arranged at the rear of the heat insulating layer; the heat insulating layer is made of the following raw materials: base glue.

[0007] The heat insulating layer is also made of the following raw materials: reinforcing filler, ablation-resistant filler, low-density filler, chopped fibers, coupling agent, and rubber curing agent.

[0008] Specifically, the thermal insulation layer is made of the following raw materials, measured by weight: 100 parts of base rubber, characterized in that 15 to 30 parts of reinforcing filler, 5 to 20 parts of ablation-resistant filler, 0 to 20 parts of low-density filler, 2 to 15 parts of chopped fibers, 0.5 to 3 parts of coupling agent, and 1 to 5 parts of rubber curing agent.

[0009] The present invention also has the following technical features:

[0010] Preferably, the base glue is a combination of a solid base glue and a liquid base glue, and the solid-liquid ratio of the solid base glue to the liquid base glue is (1-4):1.

[0011] Preferably, the solid base rubber is solid EPDM rubber, solid nitrile rubber or solid silicone rubber; the liquid base rubber is liquid EPDM rubber, liquid nitrile rubber or liquid silicone rubber.

[0012] Preferably, the reinforcing filler is precipitated silica, silicon dioxide or silicon powder.

[0013] Preferably, the ablation-resistant filler is one or a combination of more than one of zirconium boride, zinc borate, ammonium polyphosphate and boron phenolic acid.

[0014] Preferably, the low-density filler is one or a combination of hollow glass microspheres, phenolic microspheres and ceramic microspheres.

[0015] Preferably, the chopped fibers are one or a combination of chopped glass fibers, chopped high-silica fibers, chopped quartz fibers, chopped ceramic fibers, chopped carbon fibers, chopped aramid fibers, chopped polyimide fibers, and chopped polybenzimidazole fibers.

[0016] Preferably, the coupling agent is one or a combination of vinyltriethoxysilane, vinyltrimethoxysilane, γ-(methacryloyloxy)trimethoxysilane, γ-mercaptopropyltriethoxysilane and γ-(mercaptopropyl)trimethoxysilane.

[0017] Preferably, the rubber curing agent is sulfur, dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane or ethyl orthosilicate.

[0018] Preferably, the thermal insulation layer is made of the following raw materials, in parts by weight: 70 parts of solid EPDM rubber, 30 parts of liquid EPDM rubber, 20 parts of precipitated silica, 10 parts of zirconium boride, 10 parts of hollow glass microspheres, 5 parts of chopped carbon fibers, 2 parts of chopped aramid fibers, 1 part of γ-mercaptopropyltriethoxysilane, 1.5 parts of rubber curing agent sulfur, 5 parts of zinc oxide, 1 part of stearic acid, 3.5 parts of rubber vulcanization accelerator, 3 parts of tackifying resin, and 5 parts of operating oil.

[0019] The present invention also protects a method for integrated molding of the thermal insulation layer-front and rear joint assembly as described above, wherein the method uses an integrated molding die to achieve integrated compression molding of the thermal insulation layer, the front joint and the rear joint.

[0020] The integrated molding die comprises a left half mold and a right half mold, wherein a core mold is coaxially and detachably installed in the left half mold and the right half mold; the slit cavity between the left half mold, the right half mold and the core mold is a heat-insulating layer profile cavity.

[0021] The left half mold and the right half mold outside the cavity of the heat insulation layer mold surface are also provided with a front joint clamping groove and a rear joint clamping groove; the core mold is also provided with a front joint sleeve part and a rear joint sleeve part.

[0022] The left and right half molds outside the heat insulation layer profile cavity are also provided with a loading chamber connected with the heat insulation layer profile cavity through a feed hole; a pressure head is installed on the loading chamber.

[0023] Preferably, the left half mold and the right half mold are also provided with core mold locating pins, and the core mold is provided with a core mold locating hole, and the core mold locating hole can cooperate with the core mold locating pins.

[0024] Preferably, the pressure head is provided with pressure teeth, and the pressure teeth can cooperate with the charging chamber.

[0025] Preferably, an overflow groove is also provided on the inner wall of the insulation layer profile cavity.

[0026] Preferably, the left half mold and the right half mold outside the insulation layer profile cavity are further provided with half mold positioning holes, half mold positioning pins and half mold connecting screw holes.

[0027] Compared with the prior art, the present invention has the following technical effects:

[0028] (I) The present invention proposes a rubber-based thermal insulation layer material with good comprehensive performance and good molding fluidity, which can achieve the requirements of the molding integration process.

[0029] (II) The thermal insulation layer-front and rear joint assembly integrated molding method of the present invention effectively overcomes the problems of complicated procedures, low efficiency and poor quality consistency caused by the step-by-step preparation and manual bonding of the thermal insulation layer and the front and rear joints and other components in the prior art.

[0030] (III) The thermal insulation layer-front and rear joint assembly integrated molding method of the present invention can be achieved by direct molding and curing with a special mold, or by transferring the mold to a curing furnace for heating and curing after tightening the screws.

[0031] (IV) The thermal insulation layer-front and rear joint assembly integrated molding method of the present invention can be quickly prepared and molded. While achieving material properties that meet design requirements, it has the advantages of simple operation, low cost and strong process adaptability, and provides a new idea for high-quality, low-cost manufacturing of new solid rocket engine composite material shells in the fields of aerospace and weapon equipment manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the structure of the insulation layer-front and rear joint components.

[0033] Figure 2 It is a structural schematic diagram of the front joint.

[0034] Figure 3 Schematic diagram of the structure of the rear joint.

[0035] Figure 4 Schematic diagram of the decomposed structure of the integrated molding die.

[0036] Figure 5 It is a schematic diagram of the mold closing state of the integrated molding mold.

[0037] Figure 6 This is a schematic diagram of the integrated molding mold after the outer mold is removed.

[0038] The meanings of the numbers in the figure are: 1-insulation layer, 2-front joint, 3-rear joint, 4-integrated molding mold.

[0039] 401-left half mold, 402-right half mold, 403-core mold, 404-insulation layer surface cavity, 405-core mold locating pin, 406-core mold locating hole, 407-front joint slot, 408-rear joint slot, 409-front joint sleeve part, 410-rear joint sleeve part, 411-feeding hole, 412-charging chamber, 413-pressing head, 414-pressing teeth, 415-overflow groove, 416-half mold locating hole, 417-half mold locating pin, 418-half mold connecting screw hole.

[0040] The specific contents of the present invention are further described in detail below in conjunction with the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0041] It should be noted that all components and raw materials in the present invention, unless otherwise specified, are all components and raw materials known in the prior art. For example, the base rubber and chopped fibers mentioned in the present invention are all raw materials known in the market in the art.

[0042] In accordance with the above technical scheme, specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical scheme of this application fall within the protection scope of the present invention.

[0043] Embodiment 1:

[0044] This embodiment provides a thermal insulation layer-front and rear joint assembly, such as Figures 1 to 3 As shown, it comprises a heat insulating layer 1 , a front joint 2 is arranged at the front of the heat insulating layer 1 , and a rear joint 3 is arranged at the rear of the heat insulating layer 1 .

[0045] The heat-insulating layer 1 is made of the following raw materials, measured by weight: 70 parts of solid EPDM rubber, 30 parts of liquid EPDM rubber, 20 parts of precipitated silica, 10 parts of zirconium boride, 10 parts of hollow glass microspheres, 5 parts of chopped carbon fibers, 2 parts of chopped aramid fibers, 1 part of γ-mercaptopropyltriethoxysilane, 1.5 parts of rubber curing agent sulfur, 5 parts of zinc oxide, 1 part of stearic acid, 3.5 parts of rubber vulcanization accelerator, 3 parts of tackifying resin, and 5 parts of operating oil.

[0046] In this embodiment, the solid EPDM rubber and the liquid EPDM rubber are commercially available solid EPDM rubber and liquid EPDM rubber commonly used in industry.

[0047] In this embodiment, the chopped carbon fibers and the chopped aramid fibers are both commonly used chopped fibers known in the art, and the specifications of the chopped carbon fibers and the chopped aramid fibers are both 6 mm.

[0048] In this embodiment, zinc oxide is , stearic acid is , rubber vulcanization accelerator, tackifying resin and process oil are all rubber additives.

[0049] In this embodiment, the rubber vulcanization accelerator is a commercially available rubber vulcanization accelerator commonly used in industry, for example, M (2-thiolbenzothiazole) or D (diphenylguanidine) is used as the rubber vulcanization accelerator.

[0050] In this embodiment, the tackifying resin is a commercially available industrial tackifying resin, such as rosin or α-terpene resin.

[0051] In this embodiment, the process oil is commercially available industrial process oil, for example, cyclohexane oil is used as the process oil.

[0052] In this embodiment, the development of the insulation layer-front and rear joint assembly in a small solid rocket engine composite shell is preferably used as an example for explanation. The target composite shell is a large opening structure at one end, so the structural features of the insulation layer-front and rear joint assembly are: the front joint 2 and the insulation layer 1 area where the front joint 2 is set are a closed structure, and the rear joint 3 and the insulation layer 1 area where the rear joint 3 is set are a large opening structure, and its specific structure is determined in the overall design stage of the solid rocket engine.

[0053] In this embodiment, Figure 2 and Figure 3 As shown, the shapes and materials of the front joint 2 and the rear joint 3 are usually determined and processed by the overall design of the engine, and the front joint 2 and the rear joint 3 are usually made of metal.

[0054] In this embodiment, the preparation process of the raw material of the insulation layer 1 is as follows: a low-density filler, chopped fibers, and a portion of a coupling agent are added to a liquid base rubber using a kneader, a mixer, or an internal mixer to prepare a fiber masterbatch; after adding a solid base rubber roll on an open mixer, reinforcing fillers, rubber additives, ablation-resistant fillers, the remaining coupling agent, the fiber masterbatch, and a curing agent are added to the solid base rubber and plasticized evenly to obtain the raw material for the insulation layer.

[0055] Embodiment 2:

[0056] This embodiment provides a method for integrated molding of a heat insulating layer-front and rear joint assembly. The method uses an integrated molding die 4 to achieve integrated compression molding of the heat insulating layer, the front joint and the rear joint.

[0057] like Figure 4 As shown, the integrated molding mold 4 includes a left half mold 401 and a right half mold 402, and a core mold 403 is coaxially and detachably installed inside the left half mold 401 and the right half mold 402; the slit cavity between the left half mold 401, the right half mold 402 and the core mold 403 is an insulating layer profile cavity 404.

[0058] like Figure 4 As shown, the left half mold 401 and the right half mold 402 are further provided with core mold positioning pins 405 , and the core mold 403 is provided with a core mold positioning hole 406 , which can cooperate with the core mold positioning pins 405 .

[0059] like Figure 4 As shown, the left half mold 401 and the right half mold 402 outside the insulation layer mold cavity 404 are also provided with a front joint slot 407 and a rear joint slot 408; the core mold 403 is also provided with a front joint sleeve portion 409 and a rear joint sleeve portion 410.

[0060] like Figure 4As shown, a loading chamber 412 connected to the heat-insulating layer profile cavity 404 through a feed hole 411 is also provided on the left half mold 401 and the right half mold 402 outside the heat-insulating layer profile cavity 404; a pressure head 413 is installed on the loading chamber 412, and a pressure tooth 414 is provided on the pressure head 413, and the pressure tooth 414 can cooperate with the loading chamber 412; an overflow groove 415 is also provided on the inner wall of the heat-insulating layer profile cavity 404.

[0061] like Figure 4 As shown, the left half mold and the right half mold outside the insulation layer profile cavity 414 are also provided with half mold positioning holes 416, half mold positioning pins 417 and half mold connecting screw holes 418.

[0062] In this embodiment, the inner surface of the insulating layer mold cavity 404 and the outer surface of the core mold 403 should be hardened and polished, or coated with polytetrafluoroethylene to prevent the mold wall from sticking to the insulating layer.

[0063] The integrated molding method comprises the following steps:

[0064] Step 1: Mold preparation:

[0065] Clean the surfaces of the left half mold 401 , the right half mold 402 , the core mold 403 and the pressing head 413 .

[0066] Step 2: Joint pretreatment:

[0067] The areas on the front joint 2 and the rear joint 3 to be bonded with the thermal insulation layer 1 are sandblasted and cleaned.

[0068] Step 3: Mold assembly:

[0069] like Figure 5 As shown, the front joint 2 and the rear joint 3 are mounted on the core mold 403; the front joint 2, the rear joint 3 and the core mold 403 are installed on the left half mold 401, the front joint 2 is embedded in the front joint slot 407, the rear joint 3 is embedded in the rear joint slot 408, and the core mold locating pin 405 is inserted into the core mold locating hole 406; the right half mold 402 is covered, the left half mold 401 and the right half mold 402 are locked with bolts, the locked mold is placed on a flat vulcanizer, and the integrated molding mold 4 and the pressing head 413 are preheated.

[0070] Step 4: prepare the insulation layer raw materials.

[0071] Step 5: Molding the insulation layer-front and rear joint assembly rough blank:

[0072] After the integrated molding die 4 and the pressing head 413 are preheated, the insulation layer raw material is evenly spread in the loading chamber 412, the pressing head 413 is placed, and the hydraulic pressure is started for molding. The molded part is cured by heat preservation, cooled and demolded. Figure 6As shown, a rough blank of the insulation layer-front and rear joint assembly is prepared.

[0073] In step 5, specific molding process conditions, such as temperature, pressure and time, are determined according to the type of thermal insulation layer. In the heat preservation and curing stage, the left half mold 401, the right half mold 402 and the pressing head 413 can also be locked by bolts; then the locked integrated molding mold 4 is placed in a curing furnace for heating and curing.

[0074] Step 6: Shape the rough blank of the insulation layer-front and rear joint assembly to obtain Figure 1 Insulation layer - front and rear joint assembly shown.

Claims

1. A heat insulating layer-front and rear joint assembly, comprising a heat insulating layer (1), a front joint (2) being arranged at the front of the heat insulating layer (1), and a rear joint (3) being arranged at the rear of the heat insulating layer (1); the heat insulating layer (1) is made of the following raw materials: base glue, characterized in that: The thermal insulation layer (1) is also made of the following raw materials: reinforcing filler, ablation-resistant filler, low-density filler, chopped fibers, coupling agent, and rubber curing agent.

2. The heat insulation layer-front and rear joint assembly according to claim 1, wherein the heat insulation layer (1) is made of the following raw materials in parts by weight: 100 parts of base glue, characterized in that: The reinforcing filler is 15 to 30 parts, the ablation-resistant filler is 5 to 20 parts, the low-density filler is 0 to 20 parts, the short-cut fiber is 2 to 15 parts, the coupling agent is 0.5 to 3 parts, and the rubber curing agent is 1 to 5 parts.

3. The thermal insulation layer-front and rear joint assembly according to claim 1, characterized in that: The base glue is a combination of a solid base glue and a liquid base glue, and the solid-liquid ratio of the solid base glue to the liquid base glue is (1-4):

1.

4. The heat insulation layer-front and rear joint assembly as claimed in claim 3, wherein the solid base rubber is solid EPDM rubber, solid nitrile rubber or solid silicone rubber; the liquid base rubber is liquid EPDM rubber, liquid nitrile rubber or liquid silicone rubber; Features: The reinforcing filler is precipitated white carbon black, silicon dioxide or silicon powder; The ablation-resistant filler is one or a combination of zirconium boride, zinc borate, ammonium polyphosphate and boron phenolic acid; The low-density filler is one or a combination of hollow glass microspheres, phenolic microspheres and ceramic microspheres; The chopped fibers are one or a combination of chopped glass fibers, chopped high-silica fibers, chopped quartz fibers, chopped ceramic fibers, chopped carbon fibers, chopped aramid fibers, chopped polyimide fibers, and chopped polybenzimidazole fibers; The coupling agent is one or a combination of vinyl triethoxysilane, vinyl trimethoxysilane, γ-(methacryloyloxy) trimethoxysilane, γ-mercaptopropyl triethoxysilane and γ-(mercaptopropyl) trimethoxysilane; The rubber curing agent is sulfur, dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane or ethyl orthosilicate.

5. The thermal insulation layer-front and rear joint assembly according to claim 3, characterized in that: The thermal insulation layer is made of the following raw materials, measured by weight: 70 parts of solid EPDM rubber, 30 parts of liquid EPDM rubber, 20 parts of precipitated silica, 10 parts of zirconium boride, 10 parts of hollow glass microspheres, 5 parts of chopped carbon fibers, 2 parts of chopped aramid fibers, 1 part of γ-mercaptopropyltriethoxysilane, 1.5 parts of rubber curing agent sulfur, 5 parts of zinc oxide, 1 part of stearic acid, 3.5 parts of rubber vulcanization accelerator, 3 parts of tackifying resin, and 5 parts of operating oil.

6. A method for integrally forming a heat insulation layer-front and rear joint assembly according to any one of claims 1 to 5, characterized in that: The method adopts an integrated molding die (4) to realize integrated molding of the heat insulating layer, the front joint and the rear joint; The integrated molding die (4) comprises a left half mold (401) and a right half mold (402), wherein a core mold (403) is coaxially and detachably installed in the left half mold (401) and the right half mold (402); the slit cavity between the left half mold (401), the right half mold (402) and the core mold (403) is a heat-insulating layer profile cavity (404); A front joint slot (407) and a rear joint slot (408) are also provided on the left half mold (401) and the right half mold (402) outside the insulating layer mold cavity (404); a front joint sleeve portion (409) and a rear joint sleeve portion (410) are also provided on the core mold (403); The left half mold (401) and the right half mold (402) outside the insulating layer profile cavity (404) are also provided with a loading chamber (412) connected to the insulating layer profile cavity (404) through a feed hole (411); a pressure head (413) is installed on the loading chamber (412).

7. The method for integrated molding of the thermal insulation layer-front and rear joint assembly according to claim 6, characterized in that: The left half mold (401) and the right half mold (402) are also provided with a core mold positioning pin (405), and the core mold (403) is provided with a core mold positioning hole (406), and the core mold positioning hole (406) can cooperate with the core mold positioning pin (405).

8. The method for integrated molding of the thermal insulation layer-front and rear joint assembly according to claim 6, characterized in that: The pressure head (413) is provided with pressure teeth (414), and the pressure teeth (414) can cooperate with the charging chamber (412).

9. The method for integrated molding of the thermal insulation layer-front and rear joint assembly according to claim 6, characterized in that: An overflow groove (415) is also provided on the inner wall of the heat insulation layer profile cavity (404).

10. The method for integrated molding of the thermal insulation layer-front and rear joint assembly according to claim 6, characterized in that: The left half mold and the right half mold outside the heat insulation layer profile cavity (414) are also provided with half mold positioning holes (416), half mold positioning pins (417) and half mold connecting screw holes (418).

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