Forming device and forming method for large-size composite barrel

Abstract

The embodiment of the invention discloses a forming device and method for a large-size composite barrel. The device comprises an upper die, a lower die and a sealing assembly. The upper die and the lower die are each of a combined structure of a thin-wall type frame structure and a die body, each frame structure is formed by welding transverse and longitudinal thin plates in a staggered mode, and the corresponding die body is welded to the inner side of each frame structure. The die body is formed into an inner molded surface of the die body through roll forming by metal plates with the same thickness, and the inner molded surface of the die body comprises a working molded surface and a parting surface; after the upper die and the lower die are in butt joint, a working profile used for forming a composite barrel is formed through the upper die body and the lower die body on the inner side, and positioning butt joint of the upper die and the lower die is achieved through the upper die parting face and the lower die parting face. A sealing assembly is arranged between the parting surfaces of the upper mold and the lower mold, inert gas is introduced in the forming process through a silicone tube penetrating through the parting surfaces on the two sides in the sealing assembly, and the sealing effect of the parting surfaces of the upper mold and the lower mold is achieved through expansion of the silicone tube.

Description

Technical Field

[0001] This invention relates to, but is not limited to, the field of large-size composite material cylinder molding technology, and particularly to a molding apparatus and molding method for large-size composite material cylinders. Background Technology

[0002] For the molding method of composite material cylinders, the molding mold consists of a molding cavity formed by end caps, composite core molds, upper molds and lower molds to carry out the molding process.

[0003] Currently, for the molding dies of the aforementioned composite material cylinders, the composite core mold requires a complex combination mold using a metal core and silicone rubber for pressure molding. This process is complex, involving the disassembly and reassembly of numerous mold parts; examples include CN222522083U, a molding tooling for a variable cross-section composite material cylinder, and CN220428998U, a molding die for a large composite material cylinder. Alternatively, the core mold can be prepared as a sand core through a molding process, as illustrated in CN118720050A, a molding tooling and manufacturing method for a high-pressure composite material cylinder sand core; however, the sand core product has poor internal and external surfaces, the molding process is cumbersome, and the sand core is only for single use, increasing manufacturing costs. Summary of the Invention

[0004] The purpose of this invention is to solve the above-mentioned technical problems. This invention provides a molding device and molding method for large-size composite cylinders, so as to solve the technical difficulties of complex composite core mold molding process and high cost in large-size non-rotational composite cylinder products.

[0005] The technical solution of the present invention: The present invention provides a forming device for large-size composite cylinders, including: an upper mold 1, a lower mold 2, and a sealing component 4; The upper mold 1 and the lower mold 2 are both configured as a combination of a thin-walled frame structure and a mold body. The frame structure is formed by interlacing thin plates in the horizontal and vertical directions, and the corresponding mold body is welded to the inner side of the frame structure. The mold body is formed by rolling metal plates of equal thickness into the inner surface of the mold body, which includes a working surface and a parting surface. After the upper mold 1 and the lower mold 2 are connected, the inner upper and lower mold bodies form a working surface for molding the composite cylinder, and the upper mold 1 and the lower mold 2 are positioned and connected through the upper and lower parting surfaces; a sealing component 4 is provided between the parting surfaces of the upper mold 1 and the lower mold 2. Inert gas is introduced through the silicone tube that passes through the parting surfaces on both sides of the sealing component 4 during the molding process, so as to achieve the sealing effect of the parting surfaces of the upper mold 1 and the lower mold 2 through the expansion of the silicone tube.

[0006] Optionally, in the molding apparatus for large-size composite cylinders as described above, The upper mold 1 and lower mold 2 are formed by rolling metal plates. The frame structure is formed by welding horizontal and vertical metal plates. The non-connecting parts between the metal plates are hollowed out. The connecting surface between the frame structure and the mold body is obtained by CNC machining according to the shape of the mold body. The two are welded when they are in a free fit state with a gap of 1-2mm.

[0007] Optionally, in the forming device for large-size composite cylinders as described above, the parting surfaces of the upper mold 1 and the lower mold 2 are provided with anti-leakage blocks on the back of the mold body at the positioning connection position, and the anti-leakage blocks are sealed and welded to the back of the mold body. A pre-defined bag-making area is reserved on the template frame on both sides of the upper mold 1 and the lower mold 2.

[0008] Optionally, in the molding apparatus for large-size composite cylinders as described above, the sealing assembly 4 includes: a silicone tube 401, a mounting plate 402, an inflation connector cap 403, a quick-change connector 404, and a connector 405; Among them, the parting surface of the upper mold 1 is a plane located on both sides of the working surface, and the two side surface areas of the parting surface of the lower mold 2 are respectively provided with grooves along the axial direction of the working surface, and a silicone tube 401 is placed in each groove. Each silicone tube 401 has a connector 405 installed at both ends. One end of the connector 405 is pressed into the through hole of the mounting plate 402 with an interference fit. The silicone tube 401 passes through the mounting plate 402 and the connector 405 in sequence and then turns outward. The outward silicone tube 401 and the connector 405 are inserted into the inflation connector cap 403 and pressed tightly. The quick-change connector 404 is connected to the inflation connector cap 403 by a threaded fit.

[0009] Optionally, the forming device for large-size composite cylinders described above further includes: multiple sets of guide components 5 for closing the upper mold 1 and the lower mold 2; each set of guide components 5 includes: two supports 501, a conical sleeve 502, and a conical pin 503; Two supports 501 are respectively set at corresponding positions on the sides of the upper mold 1 and the lower mold 2, and are arranged symmetrically in the upper and lower positions. Each support 501 includes a connecting seat that is fixedly installed on the upper mold 1 or the lower mold 2, and a connecting pipe set on the end face of the connecting seat. The opposite end faces of the two connecting pipes have annular bosses. A tapered pin 503 is installed on the annular boss at one end of the connecting pipe, and a tapered sleeve 502 is installed in the center hole of the annular boss at the other end of the connecting pipe. This is used to guide the upper mold 1 and the lower mold 2 to dock through the tapered pin 503 and the tapered sleeve 502.

[0010] Optionally, the forming device for large-size composite cylinders described above further includes: a positioning component 7; the positioning component 7 includes a ball head pin 701, a fixing bushing I 702, and a fixing bushing II 703; Among them, the fixed bushing I 702 and the fixed bushing II 703 are installed in the holes outside the sealing grooves of the parting surface in the upper mold 1 and the lower mold 2 with an interference fit. The smooth part of the ball head pin 701 is installed in the fixed bushing I 702 with an interference fit, and the ball head part is positioned in conjunction with the fixed bushing II 703.

[0011] Optionally, the forming device for large-size composite cylinders described above further includes: a buffer assembly 6; the buffer assembly 6 includes: a first support 601, a screw 602, a second support 603, a compression spring 604, and a washer 605; The first support 601 is configured as an L-shaped support, which is fixedly connected to the side of the upper mold 1 through its side plate. The screw 602 extends out of the bottom plate after its threaded end passes through the nut located above the bottom plate of the L-shaped support, and the extension length of the screw 602 is adjusted by the nut. The second support 603 is fixedly connected to the side of the lower mold 2 through its side plate. A compression spring 604 and a washer 605 are installed in the slot of the connecting seat fixed on the side plate, and the extension end of the screw 602 is directly opposite the washer 605 on the top of the second support 603. When the lower mold 2 and the upper mold 1 are closed, the screw 602 in the first support 601 presses against the washer 605 of the second support 603, and the compression spring 604 provides a buffering force when the mold is closed.

[0012] Optionally, the forming apparatus for large-size composite cylinders described above further includes: a base frame 3; The lower mold 2 is fixedly installed on the base frame 3, which provides a rigid support reference for the overall molding device when the ground is uneven.

[0013] In a second aspect, the present invention also provides a method for forming a large-size composite cylinder, wherein the method for forming the large-size composite cylinder is performed using a forming apparatus for large-size composite cylinders as described in any of the preceding claims, comprising: Step 1, lay-up and sealing, includes: The composite material is laid on the working surfaces of the upper mold 1 and the lower mold 2 respectively. When laying on the working surfaces of the upper mold 1 and the lower mold 2, an overlap layer of a preset width is extended outward along the working surface. When the mold is closed, the overlap layers of the material lay-up extended in the upper mold 1 and the lower mold 2 are overlapped according to the product lay-up diagram. The layers in the upper and lower overlap layers are staggered at the overlap position. The silicone tube is placed in the groove of the mold closing surface of the lower mold 2. Step 2, mold closing, includes: The upper mold 1 is transferred to the upper mold 2 and slowly lowered. The guide component 55 is used for initial positioning. As the upper mold 1 slowly descends, the pressure of the upper mold 1 falling due to gravity is reduced by the buffer component 6. The positioning bushing installed on the mold closing surface of the upper mold 1 contacts the positioning ball head pin of the lower mold 2 to complete the mold closing. After the mold closing is completed, the inflatable connector cap 403 and quick-change connector 404 are installed on the silicone tube end in the sealing component 4 and installed on both end faces of the mold body through the connecting plate 402.

[0014] Step 3, install the vacuum bag and vacuum tubing, including: Vacuum bags are placed over the areas of the upper mold 1 and lower mold 2, with the vacuum bags extending outward from both sides of the mold body and folded over to fit the end faces of both sides of the mold body. The edges are sealed with vacuum sealing tape and the vacuum lines are connected. Step 4, Vacuuming: Start the vacuum pump to extract the air from the mold vacuum bag, creating negative pressure. Set the pressure value according to product requirements.

[0015] Step 5, Curing and Molding: The molding device and product are laid up in an autoclave and heated and cured according to the required temperature and pressure.

[0016] Step 6, Demolding: After curing, remove the product from the molding device and clean the upper mold 1 and lower mold 2, as well as any excess resin and glue on the parting surface.

[0017] The beneficial effects of this invention are as follows: Large-size composite cylinders are rare in previous products. Most cylinder products are composite material bonded structures or produced using winding processes, both of which require composite mandrels. As mentioned above, the preparation of composite mandrels presents technical challenges such as complex molding processes and high costs. This invention provides a molding device and method for large-size composite cylinders. Through the determination of the type and material of the molding device, the structural design of the device, the stiffness analysis of the device structure, the optimization of the device structure, and the use of the device, the feasibility of using a metal molding device to mold large-size composite cylinders is verified. Specifically, the mandrel molding method is optimized to vacuum pressure molding, resulting in a simple mold structure. A combined mold form is adopted, with thin-shell designs for the upper and lower molds to reduce the impact of tooling weight and heating rate. Rigidity analysis is used for optimization design. Mold design and sealing technology are the core design points of this invention. Using the technical solution provided by this invention for molding such cylinders improves the product's shape accuracy and quality. It solves the long-standing difficulties in molding composite cylinders, such as complex existing tooling structures, complex processes, generally poor product molding quality, and short service life of existing tooling. The forming device provided by this invention has been applied to the forming of the tail beam cylinder of the WG type. After the tooling was manufactured, it was verified and the production task of the model was completed. It can also be extended to other models. Attached Figure Description

[0018] The accompanying drawings are provided to further understand the technical solutions of the present invention and constitute a part of the specification. They are used together with the embodiments of this application to explain the technical solutions of the present invention and do not constitute a limitation on the technical solutions of the present invention.

[0019] Figure 1 This is a schematic diagram of the overall structure of a molding device for large-size composite cylinders provided in an embodiment of the present invention; Figure 2 for Figure 1 The illustrated embodiment provides a side view of a molding apparatus for large-size composite cylinders; Figure 3 is Figure 1 The illustrated embodiment provides a cross-sectional view of a molding apparatus for large-size composite cylinders; Figure 3a is a cross-sectional view in the axial position, and Figure 3b is a partially enlarged schematic diagram of Figure 3a. Figure 4 for Figure 1 The illustrated embodiment provides a schematic diagram of the sealing assembly in a molding apparatus for large-size composite cylinders. Figure 5 for Figure 4 The side view and cross-sectional view of the sealing assembly provided in the illustrated embodiment are shown. Figure 5 Figure a is a sectional view, and figure b is a side view; Figure 6 for Figure 1 The illustrated embodiment provides a schematic diagram of the guide assembly in a forming apparatus for large-size composite cylinders. Figure 6 Figure a is a front view of the buffer component, and Figure b is a cross-sectional view of Figure a along EE; Figure 7 for Figure 1 The schematic diagram shown is of the structure of the buffer assembly in the molding apparatus for large-size composite cylinders provided in the embodiment. Figure 7 Figure a is the front view, and figure b is the sectional view of figure a along FF. Figure 8 Figure 1 The illustrated embodiment provides a schematic diagram of the positioning component in a forming apparatus for large-size composite cylinders. Figure 8 Figure a is the external view, and Figure b is the cross-sectional view of Figure a along DD.

[0020] Explanation of reference numerals in the attached figures: 1-Upper mold, 2-Lower mold, 3-Base frame, 4-Sealing assembly, 5-Guide assembly, 6-Buffer assembly; 401-Silicone tube, 402-Mounting plate, 403-Inflatable connector cap, 404-Quick-change connector, 405 Connector; 501-Support, 502-Conical sleeve, 503-Conical pin; 601-First support, 602-Screw, 603-Second support, 604-Compression spring, 605 Washer; 701-Ball pin, 702-Fixed bushing I, 703-Fixed bushing II. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

[0022] As explained in the background section above, the molding of composite core molds for large-size non-rotational composite cylindrical products presents technical challenges such as complex processes and high costs.

[0023] To address the aforementioned problems, this invention provides a molding apparatus and method for large-size composite cylinders, which solves the problems of complex processes, generally poor product molding quality, and short mold lifespan in existing technologies.

[0024] The present invention provides the following specific embodiments, which can be combined with each other. For the same or similar concepts or processes, they may not be described again in some embodiments.

[0025] In this embodiment of the invention, a molding process of vacuum bag pressurization + autoclave heating is adopted for the molding of large-size composite cylinders. This invention has formulated a complete technical solution through the determination of tooling types and materials, the design of tooling structures, the stiffness analysis of tooling structures, the optimization of tooling structures, and the development of auxiliary operating devices for the tooling.

[0026] In a first aspect, the present invention provides a molding method for large-size composite cylindrical bodies. The molding method provided by the present invention is described through the following process conditions and molding steps.

[0027] 1. Process conditions a) Molding process method: The product is cured using a vacuum bag autoclave with a negative pressure requirement of 0.08 MPa.

[0028] b) Molding pressure and pressurizing equipment: 0.2 MPa, autoclave.

[0029] C) Molding temperature and pressurization equipment: 185℃, autoclave.

[0030] 2. Molding steps Steps of vacuum bag forming method a) Prepare molds and materials The mold surface is cleaned and ready for use, along with composite materials (carbon fiber) and auxiliary materials (resin, etc.).

[0031] b) Pile The composite material (carbon fiber) is laid onto the mold according to the product design requirements. After the layup is completed, the tooling is used to close the mold.

[0032] c) Vacuum bags and vacuum tubing Cover the mold application area with a vacuum bag, seal the edges with vacuum sealing tape, and connect the vacuum tubing.

[0033] d) Vacuuming Start the vacuum pump to extract the air from the mold vacuum bag, creating negative pressure. The pressure value should be as per product requirements.

[0034] e) Curing and molding The mold is heated and cured in an autoclave according to the temperature and pressure required for product curing.

[0035] f) Mold opening Once cured, remove the product from the mold and clean off any excess material.

[0036] Secondly, the present invention provides a forming apparatus for large-size composite cylindrical bodies. The molding process of the molding method of the present invention, and the design scheme of the molding device provided by the present invention are as follows: 1. Material selection scheme for molding equipment Based on the forming process and production requirements, the forming device is made of metal (mainly Invar steel and Q235 steel).

[0037] 2. Structural design scheme of molding device like Figure 1 As shown in Figure 3, the structure of the molding device for large-size composite cylinders provided in this embodiment of the invention adopts a combined mold form according to the product shape, that is, the main mold body of the molding device is divided into an upper mold and a lower mold, which reduces the complicated work caused by too many cover plates, core molds, etc.

[0038] The upper and lower molds have similar structures, both being a combination of a thin-walled frame structure and a mold body. The frame structures of the upper and lower mold bodies are formed by interlacing thin plates in the horizontal and vertical directions. The corresponding mold body is welded to the inside of the frame structure. Specifically, the mold body inside the frame structure is formed by rolling metal plates of equal thickness into the inner surface of the mold body. The inner surface of the mold body includes the working surface and the parting surface, and the working surfaces of the upper and lower molds are formed according to the outer surface of the product.

[0039] In this embodiment of the invention, after the upper mold and the lower mold are connected, the inner upper and lower mold bodies form a working surface for molding the composite cylinder, and the upper mold and the lower mold are positioned and connected through the upper and lower parting surfaces; a sealing component is provided between the parting surfaces of the upper mold and the lower mold, and inert gas is introduced through the silicone tube penetrating the parting surfaces on both sides of the sealing component during the molding process, so as to achieve the sealing effect of the parting surfaces of the upper mold and the lower mold through the expansion of the silicone tube.

[0040] In one embodiment of the present invention, the upper and lower mold bodies are formed by rolling metal plates. The frame structure is formed by welding transverse and longitudinal metal plates. The non-connecting parts between the metal plates are hollowed out. The connecting surface between the frame structure and the mold body is CNC machined according to the shape of the mold body. The two are welded when they are in a free fit with a gap of 1-2mm. In addition, the parting surface of the upper and lower molds is provided with a leak-proof block on the back of the mold body at the positioning and connecting position, and the leak-proof block is sealed and welded to the back of the mold body. A bag-making area of ​​a preset width is reserved on the mold plate frame on both sides of the upper and lower molds.

[0041] In practice, the mold body is made of a 15mm thick metal plate roller, and the back is made of a 10mm thick metal plate welded frame. The non-connecting parts between the metal plates are hollowed out (for weight reduction and ventilation to achieve uniform heating or cooling). The contact surface between the frame structure and the mold body is CNC machined according to the shape of the mold body, ensuring that the two fit freely with a gap of 1-2mm before welding the mold body to the frame structure. The mold body and the frame structure's four-sided molded plate frame are sealed by welding (to ensure airtightness). The parting surfaces of the upper and lower molds are equipped with anti-leakage blocks on the back of the mold body at the positioning and connection positions, and the anti-leakage blocks are sealed and welded to the back of the mold body. A 100mm wide bag-making area is reserved on the molded plate frame on both sides of the upper and lower molds.

[0042] In one implementation of the present invention, such as Figure 1 As shown, the molding device also includes a base frame 3; the lower mold in this implementation is fixedly installed on the base frame 3, which can play a role in strengthening the structure of the overall device and in transportation; the base frame 3 is used to provide a rigid support benchmark for the overall molding device when the ground is uneven, and also has a supporting effect on the overall structure.

[0043] 3. Design scheme of the device sealing structure Sealing technology is one of the core technologies of this invention. In one embodiment of this invention, such as... Figure 4 and Figure 5 As shown, the sealing assembly of the present invention includes: silicone tube 401, mounting plate 402, inflation connector cap 403, quick-change connector 404, and connector 405.

[0044] Because the upper and lower molds need to be airtight at the joint, the parting surface of the upper mold is a plane located on both sides of the working surface. The parting surface of the lower mold has grooves on both sides of the working surface along the axial direction. Each groove contains a high-temperature and pressure-resistant silicone tube 401. The depth of the groove is slightly less than the diameter of the silicone tube by 1-1.5mm.

[0045] like Figure 4 and Figure 5 As shown, each silicone tube 401 has a connector 405 installed at both ends. One end of the connector 405 is pressed into the through hole of the mounting plate 402 with an interference fit. The silicone tube 401 passes through the mounting plate 402 and the connector 405 in sequence and then turns outward. Then, it is inserted into the inflation connector cap 403 and pressed tightly. Finally, the quick-change connector 404 is connected to the inflation connector cap 403 by a threaded fit.

[0046] Using the sealing component structure provided by the present invention, the silicone tube 401 is kept filled with nitrogen at a pressure of about 8 atmospheres during the molding process.

[0047] 4. Mold Closing Technology Solution for Molding Device Due to the large size of the product, the upper and lower molds are also large in size and weight. While structural optimization using rigidity analysis techniques can appropriately reduce weight (i.e., the frame structure of the upper and lower molds adopts a weight-reducing design), it still causes inconvenience in transportation and operation, especially during mold closing. Based on the mold closing requirements of the molding device, the molding device provided by this invention also includes the following design scheme.

[0048] 4.1, Guide Component Design Scheme: The molding apparatus provided in this embodiment of the invention further includes: multiple sets of guide components for the closing of the upper and lower molds. For example... Figure 6 As shown, each guide assembly in this invention includes: two supports 501, a conical sleeve 502, and a conical pin 503.

[0049] In specific implementation, two supports 501 are correspondingly set at corresponding positions on the sides of the upper and lower molds, and are arranged symmetrically in mirror image from the upper and lower positions. Each support 501 includes a connecting seat that is fixed to the upper or lower mold, and a connecting pipe set on the end face of the connecting seat. The opposite end faces of the two connecting pipes have annular bosses. A tapered pin 503 is installed on the annular boss at one end of the connecting pipe, and a tapered sleeve 502 is installed in the central hole of the annular boss at the other end of the connecting pipe. This is used to guide the connection between the upper and lower molds through the tapered pin 503 and the tapered sleeve 502.

[0050] 4.2, Positioning Component Design Scheme: The molding apparatus provided in this embodiment of the invention further includes: a positioning component; such as Figure 8As shown, the positioning assembly includes: a mating structure of multiple sets of ball head pins and bushings; specifically, it includes: ball head pin 701, fixed bushing I 702 and fixed bushing II 703, wherein the fixed bushing I 702 and fixed bushing II 703 are interference-fitted and installed in the holes outside the sealing grooves of the parting surface in the upper mold 1 and the lower mold 2, respectively, the smooth part of the ball head pin 701 is interference-fitted in the fixed bushing I 702, and the ball head part cooperates with the fixed bushing II 703 to achieve positioning.

[0051] 4.3 Buffer Component Design Scheme The molding apparatus provided in this embodiment of the invention further includes: a buffer assembly, which is in the form of a compression spring; specifically, the buffer assembly includes: a first support 601, a screw 602, a second support 603, a compression spring 604, and a washer 605; The first support 601 is an L-shaped support, which is fixedly connected to the side of the upper mold via its side plate. The screw 602 extends out of the bottom plate after its threaded end passes through the nut located above the bottom plate of the L-shaped support, and the extension length of the screw 602 is adjusted by the nut. The second support 603 is fixedly connected to the side of the lower mold via its side plate. A compression spring 604 and a washer 605 are installed in the slot of the connecting seat fixed on the side plate, and the extension end of the screw 602 is directly opposite the washer 605 on the top of the second support 603. When the lower mold and the upper mold are closed, the screw 602 in the first support 601 presses against the washer 605 of the second support 603, and the compression spring 604 provides a buffering force during mold closing.

[0052] 4.4, Design scheme of clamping device: The upper and lower parting surfaces of the upper and lower molds are connected by bolts, and the connecting bolts are evenly distributed outside the sealing groove area of ​​the upper and lower mold bodies.

[0053] Part Three provides implementation examples of the molding apparatus in this invention. 1. Phantom The cylindrical forming device consists of two mold bodies: an upper mold and a lower mold. To ensure the upper and lower molds can close vertically without generating lateral forces, the parting surfaces of the upper and lower mold bodies are parallel to the ground. The positioning and connecting structures of the upper and lower mold bodies are mainly located at the parting surfaces, which are the main stress points when the forming device closes. To ensure the rigidity of the parting surfaces, and considering the structure and dimensions of the positioning connections, the thickness of the lower mold body's parting surface is designed to be 25mm, and the thickness of the upper mold body's parting surface is designed to be 20mm. The thickness of the upper and lower mold body profiles is 12mm, and the thickness of the mold plate frame is 10mm.

[0054] The upper mold needs to be handled separately. It is equipped with two forklift tubes and four lifting rings for handling and hoisting. The lifting rings are used in conjunction with a crane when the upper mold is closed, opened, and transported. They also act as tie rings when the upper and lower molds of the molding device are placed on a transport trailer in the closed state.

[0055] The bottom frame 3, constructed of I-beams, serves to enhance the rigidity of the tooling structure. It features two forklift tubes along its vertical length and two more at the front and rear, facilitating tooling transport. After the upper and lower mold bodies of the molding device are closed, a crane in the air-conditioning room lifts the tooling onto a transport trailer. The molding device and the transport trailer are then transported together to the autoclave. A 10t forklift is used to transfer the molding mold onto the autoclave trailer, completing the entire transport process. Based on this transport process, lifting rings need to be installed on the molding mold to assist the crane.

[0056] 2. Sealing components At the parting line between the upper and lower molds, a groove is designed in the lower mold along the parting line. The depth of the groove is slightly less than the diameter of the silicone tube by 1-1.5mm. A high-temperature and pressure-resistant silicone tube is placed inside the groove. To achieve an airtight seal, two sets of this type of groove and silicone tube are installed on each side of the cylinder parting line. Inflation nozzles are installed at both ends of the silicone tube, which are connected to quick-connect fittings via inflation connector caps and then to the inflation pipeline. The upper mold is not grooved. After the molds are closed, the upper and lower molds contact each other, and a seal is achieved by compressing the small portion of the silicone tube protruding from the groove in the lower mold.

[0057] 3. Guiding components The guide assembly is used for initial positioning during mold closing using multiple sets of guide assemblies. The main body of the guide assembly is in the form of a support, with one side being a flat plate. The flat plate is connected to the side of the mold body via bolts and quick-release pins. A square steel connector is welded to the flat plate, with a flat plate welded to the end of the square steel. The flat plate has holes for installing tapered pins or tapered sleeves. Two supports, tapered pins, and tapered sleeves constitute one set of guide assemblies; for example, four sets are provided.

[0058] 4. Positioning components The positioning component adopts a combination structure of ball head pin and bushing. The lower mold has a ball head pin installed at the parting surface. The cylindrical part of the ball head pin is about 3mm higher than the parting surface. The bushing is installed in the hole opened at the corresponding position of the upper mold. After the initial guidance and alignment, the bushing contacts the ball head. As the mold is gradually closed, the bushing and the cylindrical part of the ball head cooperate to complete the positioning.

[0059] 5. Compression structure A clamping structure is also provided between the upper mold and the lower mold. Specifically, the upper mold and the lower mold are connected by bolts. The upper mold has a through hole and the lower mold has a threaded hole. The hole area is on the outside of the silicone tube of the mold body. The bolt hole positions are evenly distributed according to the mold length. After the bolt passes through the through hole of the upper mold, it is fixedly connected to the threaded hole at the corresponding position of the lower mold.

[0060] 6. Buffer components The buffer assembly adopts a compression spring structure. The main structure of the buffer assembly is similar to that of the guide assembly, with the main body being a support. One side of the support, mounted on the upper mold, is a flat plate, connected to the mold body side via bolts and quick-release pins. A flat plate connector with threaded holes is welded onto the flat plate for mounting the handle screw. The other side of the support, mounted on the lower mold, is also a flat plate, connected to the mold body side via bolts and quick-release pins. A sleeve connector is welded onto the sleeve, with a closed lower end containing a compression spring 604. A washer 605 is placed on the compression spring. When the upper mold descends, the screw contacts the washer on the spring, achieving the buffering purpose.

[0061] Large-size composite cylinders are rare in previous products. Most cylinder products are composite material adhesive structures or produced using winding processes, both of which require composite mandrels. As mentioned above, the preparation of composite mandrels presents technical challenges such as complex molding processes and high costs. This invention provides a molding device and method for large-size composite cylinders. Through the determination of the type and material of the molding device, the structural design of the device, the stiffness analysis of the device structure, the optimization of the device structure, and the use of the device, the feasibility of using a metal molding device to form large-size composite cylinders is verified. Specifically, the mandrel forming method is optimized to vacuum pressure forming, the mold structure is simple, a combined mold form is adopted, and the upper and lower molds adopt a thin-shell design to reduce the impact of tooling weight and heating rate. The design is optimized through rigidity analysis. The mold parting design and sealing technology are the core design points of this invention. Using the technical solution provided by this invention to form such cylinders improves the product's shape accuracy and quality. It solves the long-standing difficulties in forming composite cylinders, such as the complex structure of existing tooling, the complex process, the general product molding quality, and the short service life of existing tooling. The forming device provided by this invention has been applied to the forming of the tail beam cylinder of the WG type. After the tooling was manufactured, it was verified and the production task of the model was completed. It can also be extended to other models.

[0062] The following is an example illustrating the process of the molding method for large-size composite cylinders in the above embodiments of the present invention.

[0063] In this implementation example, the core molding method is optimized to vacuum pressure molding. The mold structure is simple, using a combined mold design. The upper and lower molds adopt a thin-shell design to reduce the weight of the tooling and the impact of the heating rate. Rigidity analysis was used for further optimization. The molding device includes: upper mold 1, lower mold 2, base frame 3, sealing assembly 4, guiding assembly 5, and buffer assembly 7. The process of implementing the molding method includes the following steps: Step 1, Lamination and Sealing The composite material (carbon fiber) is laid onto the working surfaces of the upper and lower molds according to the product design requirements. This process requires the use of layup auxiliary fixtures. During layup on the upper and lower molds, overlapping layers of a predetermined width extend outwards along the working surfaces. The overlap width is as specified in the product design. When closing the molds, the overlapping layers extending from the upper and lower molds are overlapped according to the product layup diagram. The overlapping layers are staggered. A silicone tube is placed in the groove on the lower mold's closing surface.

[0064] Step 2, mold closing The upper mold is transported above the lower mold by a forklift and slowly lowered. Initial positioning is achieved using guide assembly 5. As the upper mold descends, buffer assembly 6 reduces the compressive force exerted by its own weight. The positioning bushing installed on the upper mold's closing surface contacts the positioning ball head pin of the lower mold, completing mold closing. After mold closing, an inflation connector cap 403 and a quick-change connector 404 are installed at the end of the silicone tube in sealing assembly 4, and then connected to the two end faces of the mold body via connecting plate 402.

[0065] Step 3, Install vacuum bags and vacuum tubing Vacuum bags are placed over the areas where the upper and lower molds are laid, with the vacuum bags extending outward from both sides of the mold body and folded over to fit the end faces of both sides of the mold body. The edges are sealed with vacuum sealing tape and connected to vacuum tubing.

[0066] Step 4, Vacuuming: Start the vacuum pump to extract the air from the mold vacuum bag, creating negative pressure. Set the pressure value according to product requirements.

[0067] Step 5, Curing and Shaping The molding device and product layup are placed in an autoclave and heated and cured according to the required temperature and pressure.

[0068] Step 6, mold opening After curing, remove the product from the molding device and clean the upper and lower molds, as well as any excess resin and glue on the parting surface.

[0069] The advantages of the molding device for large-size composite cylinders provided by this invention are as follows: Large-size composite material cylinder structures are rare in previous products. Most cylinder products are composite material bonded structures or produced by winding processes, and both of these molding processes require the use of composite mandrels. As mentioned above, the preparation of composite mandrels presents technical challenges such as complex molding processes and high costs. This invention provides a molding device and method for large-size composite cylinders. Through the determination of the type and material of the molding device, the structural design of the device, the stiffness analysis of the device structure, the optimization of the device structure, and the use of the device, the feasibility of using a metal forming device to form large-size composite material cylinders has been verified. It overcomes the challenges of traditional methods, such as low operating efficiency, poor quality, and limited mold life and material limitations. The method and mold involved in this patent improve the shape accuracy and quality of the product, simplify the operation process, and increase the service life of the tooling.

[0070] Currently, this invention has been applied to the molding of other similar products, such as the molding of a certain model of tail beam cylinder. The mold material is Q235-AF, and the structural form, sealing components, and guiding components are all in accordance with this invention. The molded product meets the model requirements.

[0071] While the embodiments disclosed in this invention are as described above, they are merely illustrative of the embodiments to facilitate understanding of the invention and are not intended to limit the invention. Any person skilled in the art to which this invention pertains may make any modifications and variations in the form and details of the implementation without departing from the spirit and scope disclosed herein; however, the scope of patent protection for this invention shall still be determined by the scope defined in the appended claims.

Claims

1. A molding apparatus for large-size composite cylindrical bodies, characterized in that, include: Upper mold (1), lower mold (2), sealing assembly (4); The upper mold (1) and the lower mold (2) are both set as a combination of thin-walled frame structure and mold body. The frame structure is formed by interlacing thin plates in the horizontal and vertical directions. The corresponding mold body is welded to the inner side of the frame structure. The mold body is formed by rolling metal plates of equal thickness into the inner surface of the mold body. The inner surface of the mold body includes the working surface and the parting surface. After the upper mold (1) and the lower mold (2) are connected, the upper and lower mold bodies on the inner side form a working surface for molding the composite cylinder, and the upper mold (1) and the lower mold (2) are positioned and connected through the upper and lower parting surfaces; a sealing component (4) is provided between the parting surfaces of the upper mold (1) and the lower mold (2), and inert gas is introduced through the silicone tube that passes through the parting surfaces on both sides of the sealing component (4) during the molding process, so as to achieve the sealing effect of the parting surfaces of the upper mold (1) and the lower mold (2) through the expansion of the silicone tube.

2. The forming apparatus for large-size composite cylinders according to claim 1, characterized in that, The upper mold (1) and lower mold (2) are formed by rolling metal plates. The frame structure is formed by welding horizontal and vertical metal plates. The non-connecting parts between the metal plates are hollowed out. The connection surface between the frame structure and the mold body is obtained by CNC machining according to the shape of the mold body. The two are welded when they are in a free fit state and have a gap of 1-2mm.

3. The forming apparatus for large-size composite cylinders according to claim 2, characterized in that, The upper mold (1) and the lower mold (2) have a leak-proof block on the back of the mold body at the positioning and connection position on the parting surface, and the leak-proof block is sealed and welded to the back of the mold body. A pre-defined bagging area is reserved on the template frame on both sides of the upper mold (1) and lower mold (2).

4. The forming apparatus for large-size composite cylinders according to claim 1, characterized in that, The sealing assembly (4) includes: a silicone tube (401), a mounting plate (402), an inflation connector cap (403), a quick-change connector (404), and a connector (405). Among them, the parting surface of the upper mold (1) is a plane located on both sides of the working surface, and the two sides of the parting surface of the lower mold (2) are respectively provided with grooves along the axial direction of the working surface, and a silicone tube (401) is placed in each groove. Each silicone tube (401) has a connector (405) installed at both ends. One end of the connector (405) is pressed into the through hole of the mounting plate (402) with an interference fit. The silicone tube (401) passes through the mounting plate (402) and the connector (405) in sequence and then turns outward. The outward silicone tube (401) and the connector (405) are inserted into the inflation connector cap (403) and pressed tightly. The quick-change connector (404) is connected to the inflation connector cap (403) by a threaded fit.

5. The forming apparatus for large-size composite cylinders according to claim 1, characterized in that, Also includes: Multiple sets of guide components (5) are used when the upper mold (1) and the lower mold (2) are closed; each set of guide components (5) includes: two supports (501), a tapered sleeve (502), and a tapered pin (503); Among them, two supports (501) are respectively set at corresponding positions on the sides of the upper mold (1) and the lower mold (2), and are set in a mirror symmetrical manner from top to bottom. The support (501) includes a connecting seat that is fixedly installed on the upper mold (1) or the lower mold (2), and a connecting pipe set on the end face of the connecting seat. The two connecting pipes have annular bosses on their opposite end faces. A tapered pin (503) is installed on the annular boss at the end of one connecting pipe, and a tapered sleeve (502) is installed in the center hole of the annular boss at the end of the other connecting pipe. It is used to guide the connection between the upper mold (1) and the lower mold (2) through the tapered pin (503) and the tapered sleeve (502) when the upper mold (1) and the lower mold (2) are connected.

6. The forming apparatus for large-size composite cylinders according to claim 1, characterized in that, Also includes: Positioning component (7); the positioning component (7) includes a ball head pin (701), a fixing bushing I (702) and a fixing bushing II (703); Among them, the fixed bushing I (702) and the fixed bushing II (703) are installed in the holes outside the sealing groove of the parting surface in the upper mold (1) and the lower mold (2) with an interference fit. The smooth part of the ball head pin (701) is installed in the fixed bushing I (702) with an interference fit. The ball head part is positioned in conjunction with the fixed bushing II (703).

7. The forming apparatus for large-size composite cylinders according to claim 1, characterized in that, Also includes: Buffer assembly (6); the buffer assembly (6) includes: a first support (601), a screw (602), a second support (603), a compression spring (604), and a washer (605); The first support (601) is configured as an L-shaped support, which is fixedly connected to the side of the upper mold (1) through its side plate. The screw (602) extends out of the bottom plate after its threaded end passes through the nut located above the bottom plate of the L-shaped support, and the extension length of the screw (602) is adjusted by the nut. The second support (603) is fixedly connected to the side of the lower mold (2) through its side plate. A compression spring (604) and a washer (605) are installed in the slot of the connecting seat fixed on the side plate, and the extension end of the screw (602) is directly opposite the washer (605) on the top of the second support (603). It is used to press the screw (602) in the first support (601) against the washer (605) of the second support (603) when the lower mold (2) and the upper mold (1) are closed, and to provide a buffering force when the mold is closed by the compression spring (604).

8. A forming apparatus for large-size composite cylindrical bodies according to any one of claims 1 to 7, characterized in that, Also includes: Base frame (3); The lower mold (2) is fixedly installed on the base frame (3), which provides a rigid support reference for the overall molding device when the ground is uneven.

9. A method for forming a large-size composite cylindrical body, characterized in that, The method for forming a large-size composite cylinder using the forming apparatus for large-size composite cylinders as described in any one of claims 1 to 8 includes: Step 1, lay-up and sealing, includes: The composite material is laid on the working surfaces of the upper mold (1) and the lower mold (2) respectively. When laying on the working surfaces of the upper mold (1) and the lower mold (2), the overlapping layers of the material lay-up are extended outward along the working surfaces with a preset width. When the mold is closed, the overlapping layers of the material lay-up in the upper mold (1) and the lower mold (2) are overlapped according to the product lay-up diagram. The overlapping layers of the upper and lower overlapping layers are staggered. The silicone tube is placed in the groove of the mold closing surface of the lower mold (2). Step 2, mold closing, including: The upper mold (1) is transferred to the upper mold (2) and slowly lowered. The guide component (5) 5 is used for initial positioning. As the upper mold (1) slowly lowers, the pressure of the upper mold (1) falling due to gravity is reduced by the buffer component (6). The positioning bushing installed on the mold closing surface of the upper mold (1) contacts the positioning ball head pin of the lower mold (2) to complete the mold closing. After the mold closing is completed, the inflatable connector cap (403) and quick-change connector (404) are installed on the end of the silicone tube in the sealing component (4) and installed on the two end faces of the mold body through the connecting plate (402). Step 3, install the vacuum bag and vacuum tubing, including: Vacuum bags are placed over the paving areas of the upper mold (1) and the lower mold (2), and the vacuum bags extend from both sides of the mold body and are turned outward to fit the end faces of both sides of the mold body. The edges are sealed with vacuum sealing tape and connected to the vacuum pipeline. Step 4, Vacuuming: Start the vacuum pump to extract the air from the mold vacuum bag, creating negative pressure. Set the pressure value according to product requirements. Step 5, Curing and Molding: The molding device and product are laid up in an autoclave and heated and cured according to the required temperature and pressure. Step 6, Demolding: After curing, remove the product from the molding device and clean the upper mold (1) and lower mold (2), as well as any excess resin glue and other substances on the parting surface.

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