CN219650468U - Injection molding die for adiabatic joint of solid rocket engine - Google Patents

Abstract

The utility model relates to the technical field of solid rocket engine composite material shells, in particular to an injection molding die for a solid rocket engine heat insulation joint. The mold consists of a movable mold and a fixed mold, wherein the fixed mold comprises a mold cover, an upper mold and a male mold, the movable mold comprises a middle mold and a bottom plate, and the fixed mold is arranged on a fixed hot plate of the injection machine and is connected with a nozzle of the injection machine; the movable mould is arranged on a movable hot plate of the injection machine, a cavity and a pouring system are formed after the movable mould and the fixed mould are clamped, and the fixed mould and the movable mould are provided with a runner system, a positioning system, a sealing and glue sealing system and a vacuum system. The utility model avoids the intermediate form of the sheet material, and does not need cutting and size control, thereby simplifying the operation process, reducing the manual participation in the operation process, saving the heating time in the hot pressing process, greatly improving the molding efficiency due to extremely fast mold filling time of the heat insulating layer, realizing compact filling and meeting the technical development requirement of rapid low-cost manufacture.

Description

Injection molding die for adiabatic joint of solid rocket engine

Technical Field

The utility model relates to the technical field of solid rocket engine composite material shells, in particular to an injection molding die for a solid rocket engine heat insulation joint.

Background

With the increasing shortage of international situation, the demands for large-scale production and quick response of weaponry are more and more highlighted, and the development demands for high performance, low cost and quick response of solid rocket engines are more and more emphasized, and the heat insulation layer is taken as an important component part of the combustion chamber, and besides the ablation resistance and the quality reliability, the manufacturing approach of the heat insulation layer is one of important factors for determining the cost and the speed of the heat insulation layer. The solid rocket engine combustion chamber shell is divided into a composite shell and a metal shell, and the technology only provides a new technical method for forming the heat insulation layer of the composite end socket part.

For the composite material combustion chamber shell, the heat insulation layer of the sealing head is bonded and prefabricated into a whole with the metal joint, then bonded and combined with the residual heat insulation layers such as the barrel section and the like into a whole, and finally co-cured after the winding and forming of the composite material shell is completed. The heat-insulating sealing head is usually prefabricated by adopting the processes of mould pressing, autoclave, manual cladding and the like, wherein the mould pressing adopts a mould to vulcanize on a plate vulcanizing machine, and the process is most commonly used. The molding process specifically comprises the steps of rolling and cutting the heat insulation layer by a calender, pasting the heat insulation layer with a metal joint in a layered and laminated mode, putting the heat insulation layer into a mold, and compacting and vulcanizing the heat insulation layer by a flat vulcanizing machine. In the prior solid engine composite material shell heat insulation layer forming process in China, the quality condition of a mould pressing process product is better, the application is most extensive, and a plurality of problems still exist, firstly, sheets are used as intermediate forms, and the processes of sheet grinding, cutting, bonding and layering are added, so that the problems of long forming process period, low production efficiency and the like are caused. Secondly, the rubber parts such as heat insulation joints and heat insulation sleeves belong to typical thick-wall rubber parts, the metal mold cavity is required to be paved layer by layer, more layers are needed, gaps are easy to generate between layers and are difficult to be filled and compacted if the layering design is unreasonable, and shrinkage of rubber at different thickness parts is inconsistent, so that the molded surface of the product is deformed and the size is out of tolerance. In actual operation, the mold design often cannot give accurate shrinkage allowance, the product size deviation reaches +/-10%, and the product out-of-tolerance size needs to be repeatedly polished, so that the quality stability of the thick-wall rubber part product cannot be easily ensured. Moreover, because the mould pressing process is limited by a process method, the mould pressing process can only apply pressure to rubber through the mould closing of the female mould and the mould cover which move up and down, and for cone-shaped and columnar heat-insulating products, the mould pressing process of a flat plate press has the problems of high mould design difficulty, difficult pressure transmission, poor material filling compactness, difficult demoulding and the like, and the mould pressing process is difficult to realize. Finally, by means of heat transfer of the upper plate and the lower plate, the heat transfer efficiency is low, and the product with larger height needs to be designed into a heating couple in a die.

As known from the related patents of the seal head heat insulation layers, the majority of the patents of the seal head heat insulation layers are aimed at the metal shell, and the heat insulation layers are attached and compacted by utilizing the supporting function of the metal shell. For metal shells, it is often necessary to attach a heat insulating layer after the shell is machined. When the metal cylinder section and the seal head are of a split structure, heat insulation layers are prefabricated on the cylinder section and the seal head respectively through processes such as manual paving, coating, extrusion molding or compression molding, and then the heat insulation layers are assembled into a whole. The utility model patent with publication number of CN107584771A discloses a method for forming an inner heat insulation layer of a solid rocket engine, wherein integral forming of a cylinder section-end socket heat insulation layer is realized by a method of manual paving and air bag pressurization, and a die is opened to prefabricate an inner heat insulation layer rubber sleeve, and then a heat insulation layer is adhered. The utility model patent with publication number of CN108000888A discloses a method for integrally forming a cylinder section and a heat insulation layer of a sealing head, but has higher requirement on the fluidity of heat insulation rubber, and the heat insulation rubber needs to flow into a die cavity formed by a metal shell and a core die by gravity. However, such insulating compounds tend to have a relatively low fiber or filler content and correspondingly poor resistance to ablation. The utility model patent with publication number of CN112497699A discloses a combustion chamber barrel section-end socket heat insulation layer integrated extrusion molding system and method, and solves the technical problems of high difficulty and low efficiency in the integral molding process of the barrel section and the end socket heat insulation layer in the prior art. The system comprises a base, an extruder, a combustion chamber shell, a transition sleeve, a core die adapter flange, a support and the like, wherein the combustion chamber shell is a metal shell with a barrel section-end socket integrated structure, and the extrusion of a heat insulation layer is finished by means of the supporting function of the metal shell and cannot be used for heat insulation molding in a composite material shell.

For the heat-insulating joint with the metal joint of the composite material shell, the current common compression molding method comprises the steps of grinding, cutting, bonding, layering and hot pressing, so that the process has more defects, and the time for preparing one product is about 4-6 hours. The heat insulating layer material is added with a sheet material which is an intermediate form and quality inspection thereof, the process flow is long, and the complexity is increased; the thickness and the number of the sheet material layers are required to be accurately calculated, the operation process has strict requirements on the cutting size and the weight, otherwise, the sheet material layers are easy to be underglued or excessive, and the quality assurance difficulty coefficient is increased; the hot pressing process is usually carried out by heating from room temperature to hot pressing temperature, and the heat conduction time is long; the whole construction efficiency is low, and the manual participation is high.

Disclosure of Invention

Technical problem to be solved by the utility model

The utility model provides an injection molding die and method for a solid rocket engine adiabatic joint, which are used for solving the problems of complicated working procedures, high cost, long whole molding period and the like of the existing molding method.

In order to solve the technical problems, the utility model adopts the technical proposal

The injection molding die for the adiabatic joint of the solid rocket engine comprises a movable die and a fixed die, wherein the fixed die comprises a die cover, an upper die and a male die, the movable die comprises a middle die and a bottom plate, and the fixed die is arranged on a fixed hot plate of the injection machine and connected with a nozzle of the injection machine; the movable mould is arranged on a movable hot plate of the injection machine, a cavity and a pouring system are formed after the movable mould and the fixed mould are clamped, the fixed mould and the movable mould are provided with a runner system, a positioning system, a sealing and glue sealing system and a vacuum system,

the runner system is used for forming a runner in the process of filling a cavity in the mold after the heat insulation layer material is injected from the glue injection port of the injection machine, providing a glue material channel for the injection mold and being positioned at the inner side of the mold sealing system;

the positioning system adopts guide posts to position among the templates and adopts bolts to carry out combination fixation;

the sealing and glue sealing system is characterized in that a cavity formed by combining a die adopts a sealing groove and sealing glue to realize sealing of the cavity, sealing glue among a die cover, an upper die, a middle die and a bottom plate is distributed outside a runner, the sealing groove is arranged to be matched with a sealing adhesive tape to seal the glue, and an interference sealing modulus is required to be designed on the bottom plate and the male die between the die and a metal joint as a sealing structure;

the vacuum system is designed in the mold cavity, the sealing effect of the vacuum in the mold cavity depends on sealing strips designed among the templates, and the vacuum system leads out a vacuumizing interface from the bottom plate.

Further, the flow channels are in the form of star-shaped flow channels, and each flow channel is subdivided into fan-shaped feeding into a product cavity.

Furthermore, the runner system adopts a cross injection runner, and 4 or more even feed inlets are uniformly distributed on the cross runner so as to increase the flow rate of injected sizing material.

Further, the guide posts and bolts of the positioning system are provided with 4 groups or more and are uniformly distributed around the die.

Further, the seal groove of the seal system is in a shape of a Chinese character 'hui' or a circular plane structure and is arranged on the outer sides of the flow channel and the product and the inner sides of the guide holes and the bolt holes.

Further, the metal joint is matched with the bottom plate of the die through the cylindrical surface of the joint root, centering is achieved, and limiting is achieved through the sealing structure of the bottom plate and the male die.

The utility model has the technical effects that

The utility model avoids the intermediate form of the sheet material, and does not need cutting and size control, thereby simplifying the operation process, reducing the manual participation in the operation process, saving the heating time in the hot pressing process, greatly improving the molding efficiency due to extremely fast mold filling time of the heat insulating layer, realizing compact filling and meeting the technical development requirement of rapid low-cost manufacture. The utility model has wider application value, is not only suitable for conventional mould pressing products, but also suitable for products with complex shapes and limited mould pressing process or mould.

Drawings

Fig. 1: an insulated joint product;

fig. 2: schematic diagram of injection runner distribution and trend scheme;

fig. 3: an overall schematic diagram of an injection mold;

fig. 4: injection runner layout and mold filling schematic diagram;

fig. 5: a mold cover and a runner trend schematic diagram;

fig. 6: an upper die and a runner trend schematic diagram;

fig. 7: a male mold schematic diagram;

fig. 8: middle mould and runner trend schematic diagram;

fig. 9: a bottom plate and a vacuum channel schematic diagram;

fig. 10: a schematic diagram of a sealing system between the die and the metal joint;

wherein: the device comprises a 1-metal joint, a 2-interface adhesive, a 3-heat insulating layer, a 4-mold cover, a 5-upper mold, a 6-middle mold, a 7-bottom plate, an 8-male mold, a 9-positioning block, a 10-upper sealing structure, a 11-lower sealing structure, a 41-sealing groove, a 42-glue injection port, a 43-cross runner, a 51-guide column, a 52-bolt hole, a 53-fan-shaped runner, a 61-joint cylindrical surface centering matching surface and a 62-vacuum channel.

Detailed Description

The injection molding refers to mounting a mold on a rubber injection molding machine, injecting a rubber material which is plasticized and preheated in a charging barrel of the injection machine into a mold cavity through a nozzle of the injection machine and a runner in the mold under the pressure of the injection machine, and vulcanizing and molding. Injection molding has the remarkable characteristics of high efficiency, high precision and low cost, and is mature in development in the civil field, such as a sealing ring and the like. The development of the military field is slow, and particularly in the aspect of injection molding of heat insulation layers in the aerospace field, the research work carried out at home is very limited.

The utility model relates to an injection molding die for a solid rocket engine heat insulation layer, which adopts the existing heat insulation material, reduces the viscosity of the heat insulation layer through plasticizing and heating effects of a rubber injection machine, applies enough pressure, injects the heat insulation material into a die cavity which is preloaded with a metal joint, continuously increases the temperature of the die to vulcanize and shape the heat insulation material, and then carries out demoulding after cooling to obtain the heat insulation joint. The heat insulating material is rubber material containing chopped fiber, the Mooney viscosity of the heat insulating layer is required to be less than 90ML100 ℃ (1+4), the scorch time is required to be more than 5min, and plasticization can be realized. The mould is designed in advance according to the shape of the heat insulation joint product, and the runner is reasonably arranged. And (3) pre-installing and fixing the metal joint in the die, and adopting protective measures for installation of non-bonding parts. The adhesive for bonding the metal joint and the heat insulation layer adopts a conventional adhesive of a mould pressing process, and the adhesive is coated and aired at the position for bonding the heat insulation layer according to the technological requirement of the adhesive. The mold is integrally arranged on the injection machine, and the glue inlet of the mold is tightly matched with the glue injection port of the injection machine. The heat insulating material is rolled out by an open mill to prepare strips with any specification which are convenient to feed to a feeding port of an injection machine. The heat insulating layer strip is fed into the feeding port of the injection machine, and under the action of the screw of the injection machine, the heat insulating layer automatically eats, extrudes, exhausts and plasticizes to become a compact viscous state. Under the pressure action of the injection machine, the adhesive fluid heat-insulating layer glue stock enters the mould cavity through the injection runner until the cavity is full of glue stock and the injection pressure is maintained. The mold is continuously heated to the vulcanization temperature of the heat insulation layer and vulcanized. And naturally cooling the die, demolding, and removing flash to form the product.

In order to make the objects, features and advantages of the technical scheme of the present utility model more obvious and comprehensible, embodiments of the technical scheme of the present utility model will be described clearly and completely with reference to the accompanying drawings. It is obvious that the described embodiments are only some embodiments of the proposed solution, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

The structural form of the injection molding mold should be uniformly determined according to the structure of the injection-vulcanized product and the type of the injection machine. The fixed die is also called an upper die part, is arranged on a fixed hot plate of the injection machine and is connected with a nozzle of the injection machine; the movable mold, also called the lower mold part, is mounted on a movable hot plate of the injection machine. And forming a cavity and a pouring system after the moving mold and the fixed mold are assembled. Aiming at the heat-insulating joint product, the technical scheme is designed into a die cover, an upper die, a male die, a middle die and a bottom plate. The die cover, the upper die and the male die are fixed dies, and the middle die and the bottom plate are movable dies. The mold comprises a runner system, a positioning system, a sealing and glue sealing system and a vacuum system. The positioning system adopts a guide post and a bolt for combined positioning, the sealing and glue sealing system adopts flatness below 0.02 and sealing glue for sealing, the glue sealing is carried out by adopting interference fit between a runner boundary die and a metal joint, and the vacuum system leads out a vacuumizing interface from a bottom plate. The specific structural form is shown in figure 3.

(1) Flow channel system

After the heat insulating layer material is injected from the glue injection port of the injection machine, the mold is filled with a runner formed in the process of the cavity. The number of the glue injection ports of the injection machine is 1, the product is an axisymmetric revolving body, the number of the product feeding ports is 4, the determined runner form is a cross runner form, the cross runner is one of star runners, and the runner form is the runner form which is easiest to ensure the balance of the runners. The cross flow channel is divided into 4 flow channels, and each flow channel is divided into fan-shaped feeding materials to enter the product cavity, as shown in fig. 4. The cross injection flow channels are uniformly distributed with 4 feed inlets, and 6, 8 or more feed inlets can be uniformly distributed to increase the flow of injected sizing material;

(2) Positioning system

The combined positioning among the die cover, the upper die, the middle die and the bottom plate is the positioning among the flat plates, and only the positioning of the common guide post and the guide sleeve is needed, as shown in fig. 6. The whole die is connected with the heating plate of the injection machine through the die hanging groove. The templates are positioned by adopting guide posts, combined and fixed by adopting bolts, and guide post holes and bolt holes are uniformly distributed around the die, can be 4 groups, can be uniformly distributed with 6 groups, 8 groups or even more groups;

(3) Sealing and glue sealing system

The cavity after the mold combination adopts a sealing groove and sealant to realize the sealing of the cavity, the sealing groove is in a shape like a Chinese character 'hui' and a circular plane structure and is arranged at the outer sides of the runner and the product and at the inner sides of the guide hole and the bolt hole; sealing the glue structure of the glue material flowing boundary by adopting the interference fit between the mould and the metal joint; the metal joint is matched with the bottom plate of the die through the cylindrical surface of the joint root, so that centering is realized, and limit is realized through the sealing structure of the bottom plate and the male die.

In order to avoid the overflow of the injected heat-insulating layer sizing material and realize the vacuum degree of the cavity in the die, a sealing and glue sealing system is designed and is divided into two conditions:

a. the mold is arranged between the molds. The sealing glue designs among the die cover, the upper die, the middle die and the bottom plate are all distributed on the outer side of the runner, and sealing grooves are designed to be matched with sealing rubber strips for sealing glue, and are shown in figure 5.

b. And the mold is arranged between the mold and the metal joint. It is necessary to design the sealing modulus with interference on the bottom plate and the male die as a sealing structure, as shown in fig. 10.

(4) Vacuum system

In order to improve the quality of injection products and avoid air inclusion, a vacuum system is designed in the mold cavity. The vacuum and the exhaust of the vacuum system are mainly led out from the bottom plate, and the vacuum of the cavity is led out from the central hole of the bottom plate after the die is combined and is connected with the vacuumizing equipment. See fig. 9. And the sealing effect of the vacuum in the cavity depends on the sealing strips designed among the templates.

The utility model provides a process method for an injection molding die of a solid rocket engine thermal insulation joint. The method comprises the following steps:

the surface of the sandblasted metal joint is uniformly coated with interface adhesive (heat insulation layer and metal) at the bonding position, and the operation is carried out according to the adhesive coating process method and the open time.

The metal joint end face is put into the injection mould cavity downwards and matched with the central hole of the mould bottom plate, and the joint centering is completed. The root of the outer cylindrical surface of the joint is tightly contacted with a dead point on the female die, so that the flowing range of the heat insulation material is limited.

A male die is arranged in the middle die, wherein the joint is tightly contacted with an upper sealing glue structure of the male die, and the flowing range of the heat insulating material is limited;

and a sealing adhesive tape is paved in a sealing groove of the upper die, and then the sealing adhesive tape is filled into the upper die through a guide post, so that the positioning of the upper die is realized. Centering of the male die is achieved through the boss by the upper die and the male die;

paving a sealing adhesive tape in a sealing groove of the die cover, and positioning in a matched manner through a guide post;

the bottom plate, the middle die, the upper die and the die cover are all fastened together through bolts.

The whole mould is arranged in the injection machine, the pouring gate is tightly butted with the injection gate of the injection machine, and the vacuumizing interface at the bottom of the mould is connected with the vacuum system of the injection machine.

Starting an injector heating system, preheating the injector system and an injection mould, wherein the temperature is 70-150 ℃, and simultaneously, the temperature is lower than the positive vulcanization temperature of the heat insulation layer. Starting a vacuum system of the injection mold, and vacuumizing the mold until the vacuum degree is not lower than 0.08MPa.

And starting an injection screw of the injection machine, feeding the heat-insulating layer blank into the injection machine, and fully plasticizing by the injection machine, wherein the time is less than the scorching time of the heat-insulating layer material.

And starting an injection procedure, injecting the heat-insulating layer material into the mold cavity through the pouring opening and the runner thereof under the injection pressure, filling the cavity, and maintaining the injection pressure.

And starting a heating program, heating to the positive vulcanization temperature of the heat-insulating layer material, and vulcanizing according to the vulcanization temperature and time of the material.

And after the vulcanizing procedure is finished, naturally cooling the mould, disassembling the mould, taking out the product, and trimming the flash to obtain the injection molding heat insulation joint product.

The utility model avoids the intermediate form of the sheet, saves the working procedures of grinding, cutting and layering, saves repeated measurement and recording of the thickness, the outer diameter and the inner diameter of each sheet, greatly simplifies the operation process, reduces the manual participation in the operation process and greatly shortens the heating time.

The plasticizing and injection of the injection molded insulating layer sizing material can be completed within a few minutes, and the time for preparing a product is about 3 hours, so that the compact filling is realized, the molding efficiency is greatly improved, and the technical development requirement of rapid low-cost manufacturing is met.

The method has wider application value, is not only suitable for conventional molded products, but also suitable for products with complex shapes and limited molding processes or molds.

Through the use, the scheme is feasible. The material properties of samples of the same kind of heat insulation layer respectively adopting injection and mould pressing processes are not obviously changed; the winding forming of a plurality of combustion chamber shells with the diameters of 300mm is finished, and the heat insulation layers are contained, so that the interface debonding phenomenon is avoided through X-ray flaw detection; the combustion chamber shell with the diameter of 300mm passes the water pressure check, so that the shell can be ensured to be sealed.

Claims (6)

1. The utility model provides a solid rocket engine adiabatic joint injection molding mould which characterized in that: the mould consists of a movable mould and a fixed mould, wherein the fixed mould comprises a mould cover, an upper mould and a male mould, the movable mould comprises a middle mould and a bottom plate, the fixed mould is arranged on a fixed hot plate of an injection machine and is connected with a nozzle of the injection machine, the movable mould is arranged on a movable hot plate of the injection machine, a cavity and a pouring system are formed after the movable mould and the fixed mould are clamped, a runner system formed by combining the fixed mould and the movable mould, a positioning system, a sealing and glue sealing system and a vacuum system are arranged,

the runner system is used for forming a runner in the process of filling a cavity in the mold after the heat insulation layer material is injected from the glue injection port of the injection machine, providing a glue material channel for the injection mold and being positioned at the inner side of the mold sealing system;

the positioning system adopts guide posts to position among the templates and adopts bolts to carry out combination fixation;

the sealing and glue sealing system is characterized in that a cavity formed by combining a die adopts a sealing groove and sealing glue to realize sealing of the cavity, sealing glue among a die cover, an upper die, a middle die and a bottom plate is distributed outside a runner, the sealing groove is arranged to be matched with a sealing adhesive tape to seal the glue, and an interference sealing modulus is required to be designed on the bottom plate and the male die between the die and a metal joint as a sealing structure;

the vacuum system is designed in the mold cavity, the sealing effect of the vacuum in the mold cavity depends on sealing strips designed among the templates, and the vacuum system leads out a vacuumizing interface from the bottom plate.

2. The solid rocket engine insulating joint injection molding die of claim 1, wherein: the flow channels are in the form of star-shaped flow channels, and each flow channel is subdivided into fan-shaped feeding and enters the product cavity.

3. The solid rocket engine insulating joint injection molding die of claim 2, wherein: the runner system adopts a cross-shaped injection runner, and 4 or more even feed inlets are uniformly distributed on the cross runner so as to increase the flow of injected sizing material.

4. The solid rocket engine insulating joint injection molding die of claim 1, wherein: the guide posts and the bolts of the positioning system are arranged in 4 groups or more and are uniformly distributed around the die.

5. The solid rocket engine insulating joint injection molding die of claim 1, wherein: the seal groove of the seal system is of a reverse-U-shaped or round plane structure and is arranged on the outer sides of the flow channel and the product and the inner sides of the guide holes and the bolt holes.

6. The solid rocket engine insulating joint injection molding die of claim 5, wherein: the metal joint is matched with the bottom plate of the die through the cylindrical surface of the joint root, centering is achieved, and limiting is achieved through the sealing structure of the bottom plate and the male die.