A composite material pull ring inner core winding forming die and a forming method thereof

Abstract

The application provides a composite material pull ring inner core winding forming die and a forming method thereof, and belongs to the technical field of composite material workpiece forming. The forming process of the composite material pull ring inner core cannot continuously wind the pull ring fiber, the compactness is not high, and the tensile strength is poor. It mainly comprises a winding core shaft, a split die assembly, two plane pressing plates and two end pressing plates. The winding core shaft comprises a winding core body and connecting shafts located at both ends of the winding core body. The split die assembly is sleeved outside the winding core body and is connected with the winding core body. The split die assembly comprises a plurality of split dies. The plurality of split dies are sequentially connected and spliced in the axial direction of the winding core shaft and are sleeved outside the winding core body. A die groove is formed between two adjacent split dies. The two end pressing plates are symmetrically arranged at the left and right ends of the split die assembly. It is mainly used for the forming of the composite material pull ring inner core.

Description

Technical Field

[0001] This invention belongs to the field of composite material workpiece molding technology, and in particular relates to a composite material pull ring inner core winding molding die and its molding method. Background Technology

[0002] Currently, compression molding or hand lay-up processes are commonly used in the molding of composite pull ring cores. However, these two processes have the following problems: During compression molding, some resin is extruded after the discontinuous fiber material impregnated with resin is pressed, causing the fiber tension to relax and the tensile strength of the product to decrease after molding; During hand lay-up molding, the content of fiber and its reinforcing materials is relatively small. At the same time, the product is a blank with excess material after molding, which requires further machining. This can easily lead to defects such as resin cracking, interlayer delamination, and poor surface quality of the cut, which can greatly damage the fiber continuity and seriously affect the tensile strength of the composite pull ring core. Summary of the Invention

[0003] In view of this, the present invention aims to provide a composite material pull ring core winding molding die and its molding method to solve the problems in the molding process of composite material pull ring cores, such as partial resin extrusion after the resin-impregnated fiber material is pressed during compression molding, which causes fiber tension relaxation and reduced load-bearing capacity; and the problems in hand lay-up molding, where pre-made blanks are processed first, which will destroy fiber continuity, causing resin cracking, interlayer interface delamination, and poor surface quality of the cut, which seriously affect the tensile strength of the composite material pull ring core.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a composite material pull ring inner core winding molding die, comprising a winding mandrel, a segmented module assembly, two planar pressure plates, and two end pressure plates. The winding mandrel includes a winding core body and connecting shafts located at both ends of the winding core body. The segmented module assembly is sleeved on the outside of the winding core body and is connected to the winding core body. The segmented module assembly includes multiple segmented molds, which are sequentially connected and sleeved on the outside of the winding core body along the axial direction of the winding mandrel. A mold groove is formed between two adjacent segmented molds. The two end pressure plates are symmetrically arranged at the left and right ends of the segmented module assembly, and the two planar pressure plates are symmetrically arranged on the upper and lower sides of the segmented module assembly.

[0005] Furthermore, fastening rods are provided at both ends of the segmented module, and one end of the fastening rod passes through multiple segmented modules in sequence and is screwed to a fastening nut.

[0006] Furthermore, a demolding baffle is provided at the rear end of the winding core. The demolding baffle is connected to one end of the winding core by screws, and the two ends of the demolding baffle are respectively in contact with one end of two fastening tie rods.

[0007] Furthermore, multiple pull rods are provided on both the upper and lower sides of the segmented module, and grooves that cooperate with the pull rods are provided on both the upper and lower ends of the two end pressure plates. The two ends of the pull rods are respectively embedded in and pass through the grooves of the two end pressure plates and are screwed to the pull rod nuts.

[0008] Furthermore, a positioning key is provided on one side of the winding core, and a keyway that cooperates with the positioning key is provided on the inner side of the segmented module.

[0009] Furthermore, a positioning groove is provided at the end of the connecting shaft at one end of the winding core.

[0010] The present invention also provides a molding method for a composite material pull ring inner core winding molding die, which includes the following steps: Step 1: Prepare and clean the wound mandrel; Step 2: Install the segmented module: After sequentially placing multiple segmented modules onto the winding core of the winding mandrel, install the fastening rod and tighten it with the fastening nut; Step 3: Install a release baffle at the tail end of the winding core, and connect and fix the winding core and the release baffle with screws; Step 4: Clean the surface of the mold groove of the segmented module; Step 5: Hoist the combined mold onto the winding machine, and clamp the positioning groove of the connecting shaft at one end of the winding core with the three-jaw chuck of the winding machine; Step 6: Impregnate epoxy resin with composite fiber and perform winding molding; Step 7: After the winding layer reaches the process thickness, place the end pressure plates at both ends; Step 8: Install flat pressure plates on the upper and lower sides of the segmented module, and install tie rods and tie rod nuts; Step 9: Remove the combined mold, apply pressure to the two end plates using the pull rod, and use C-clamps to tighten and pressurize the two flat plates, repeating this process multiple times until the mold is closed in place; Step 10: Transfer the combined mold to the curing oven for curing. After curing, demold and clean to form a pull ring preform.

[0011] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention provides a composite material pull ring inner core winding molding die and its molding method, which solves the problems of inability to continuously wind pull ring fibers, lack of internal stress in the fibers inside the product, and low product density. The product does not require secondary processing, which simplifies the production process, saves production costs, and improves production efficiency. 2. This invention provides a composite material pull ring inner core winding molding die and its molding method. The die adopts a segmented die connected in series to form a segmented module group, which can form multiple products at one time. The die has a compact structure, is easy to disassemble and assemble, and meets a series of process requirements such as winding, mold closing, and curing. Attached Figure Description

[0012] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the overall structure of a composite material pull ring inner core winding molding die according to the present invention; Figure 2 This is a schematic diagram of the composite material pull ring inner core winding molding die according to the present invention from another perspective; Figure 3 This is a schematic diagram of a portion of the structure in a composite material pull ring inner core winding molding die according to the present invention; Figure 4 This is a schematic diagram of the winding mandrel in a composite material pull ring inner core winding molding die according to the present invention; Figure 5 This is a schematic cross-sectional view of a composite material pull ring inner core winding molding die according to the present invention; Figure 6 This is a vertical cross-sectional schematic diagram of a composite material pull ring inner core winding molding die according to the present invention; Figure 7 This is a schematic diagram of the structure of a composite material pull ring inner core according to the present invention.

[0013] 1-Winding mandrel, 2-Segmented module, 3-Winding core, 4-Positioning key, 5-Fasting tie rod, 6-Demolding baffle, 7-Fasting nut, 8-Flat pressure plate, 9-End pressure plate, 10-Tie rod, 11-Tie rod nut, 12-Connecting shaft. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other, and the described embodiments are only some embodiments of the present invention, not all embodiments.

[0015] See Figure 1-7This embodiment describes a composite material pull ring inner core winding molding die, which includes a winding mandrel 1, a segmented module 2, two planar pressure plates 8, and two end pressure plates 9. The winding mandrel 1 includes a winding core 3 and connecting shafts 12 located at both ends of the winding core 3. The segmented module 2 is sleeved on the outside of the winding core 3 and is connected to the winding core 3. The segmented module 2 includes multiple segmented molds, which are sequentially connected in series along the axial direction of the winding mandrel 1 and sleeved on the outside of the winding core 3. A mold groove is formed between two adjacent segmented molds. The two end pressure plates 9 are symmetrically arranged at the left and right ends of the segmented module 2, and the two planar pressure plates 8 are symmetrically arranged on the upper and lower sides of the segmented module 2. The mold adopts the method of forming the segmented module 2 by connecting the segmented molds in series, forming multiple products at one time. The mold has a compact structure, is easy to disassemble and assemble, and meets a series of process requirements such as winding, mold closing, and curing.

[0016] In this embodiment, fastening rods 5 are provided at both ends of the segmented module 2. One end of the fastening rod 5 passes through multiple segmented modules in sequence and is screwed to the fastening nut 7. The fastening rod 5 and the fastening nut 7 are used to clamp and fix multiple segmented modules.

[0017] In this embodiment, a demolding baffle 6 is provided at the rear end of the winding core 3. The demolding baffle 6 is connected to one end of the winding core 3 by screws. The two ends of the demolding baffle 6 are respectively in contact with one end of two fastening tie rods 5. During demolding, after removing other parts, the winding core 3 is separated from the demolding baffle 6 by using the screw holes on the demolding baffle 6 and the ejector bolts, and then the products are removed one by one.

[0018] In this embodiment, the upper and lower sides of the segmented module 2 are provided with multiple pull rods 10. The upper and lower ends of the two end pressure plates 9 are provided with grooves that cooperate with the pull rods 10. The two ends of the pull rods 10 are respectively embedded in and pass through the grooves of the two end pressure plates 9 and are screwed to the pull rod nuts 11. Rotating the pull rod nuts 11 at both ends of the pull rods 10, and applying pressure to the workpiece through the end pressure plates 9 at both ends.

[0019] In this embodiment, a positioning key 4 is provided on one side of the winding core 3, and a keyway that cooperates with the positioning key 4 is provided on the inner side of the segmented module 2. The positioning key 4 and the keyway cooperate to limit and guide the winding, preventing movement during winding.

[0020] In this embodiment, a positioning groove is provided at the end of the connecting shaft 12 at one end of the winding core 3. The three-jaw chuck clamps the winding core 1 through the positioning groove, which serves to position and prevent twisting.

[0021] This embodiment also provides a molding method for a composite material pull ring inner core winding molding die, which includes the following steps: Step 1: Prepare and clean the winding mandrel 1, wipe it clean with ethyl acetate and let it dry, then apply a release agent to the surface; Step 2: Install the segmented module 2: After sequentially placing multiple segmented modules onto the winding core 3 of the winding mandrel 1, install the fastening rod 5 and tighten it with the fastening nut 7; Step 3: Install the demolding baffle 6 at the tail end of the winding core 3, and connect and fix the winding core 3 and the demolding baffle 6 with screws; Step 4: Clean the surface of the mold groove of the segmented module 2; Step 5: Hoist the combined mold to the winding machine, and clamp the positioning groove of the connecting shaft 12 at one end of the winding core 3 with the three-jaw chuck of the winding machine; Step 6: Impregnate epoxy resin with composite fiber and wind it. Control the fiber winding tension and resin content during the molding process. Reinforce the rounded corners on both sides. The reinforcing material can be carbon fiber prepreg or glass fiber prepreg, fiber cloth or chopped strand mat, surface mat. In this embodiment, carbon fiber or glass fiber impregnate epoxy resin or other high-strength, low thermal conductivity, low thermal expansion coefficient resin is used for winding. Step 7: After the winding layer reaches the process thickness, place the end pressure plates 9 at both ends; Step 8: Install flat pressure plates 8 on the upper and lower sides of the segmented module 2, and install tie rods 10 and tie rod nuts 11; Step 9: Remove the combined mold, apply pressure to the two end pressure plates 9 through the pull rod 10, and use C-clamps to tighten and press the two flat pressure plates 8. Repeat this process multiple times until the mold is closed. In this embodiment, the pressure on the end pressure plates 9 is combined with the pressure on the flat pressure plates 8, and the adhesive is gradually squeezed out to achieve the matching dimensions. Step 10: Transfer the combined mold to the curing oven for curing. After curing, demold and clean to form a pull ring preform.

[0022] This invention solves the problems of continuous winding of looped fibers, lack of internal stress in the fibers of the product, and low product density. The product does not require secondary processing, which simplifies the production process, saves production costs, and improves production efficiency.

[0023] This invention allows for the placement of reinforcing materials during the winding process, and the mold can simultaneously form multiple products. By closing the outer mold, the dimensions of the product surface can be precisely controlled, eliminating the need for excessive machining and maximizing the continuity of the fiber. The load-bearing pull ring can be used in environments with temperatures of ≥-196℃.

[0024] The mold design of this invention adopts a multi-piece assembly structure, enabling the simultaneous molding of multiple products, significantly improving production batch efficiency and reducing unit manufacturing costs. During the molding process, the precise mold-closing technology of the flat pressure plate 8 and the end pressure plate 9 strictly controls the dimensions of the product profile, achieving a dimensional accuracy of ±0.1mm, effectively reducing performance fluctuations caused by dimensional deviations. This process minimizes fiber damage caused by excessive machining in traditional processes, ensuring fiber continuity and fully utilizing the fiber's load-bearing characteristics. This results in the molded pull ring exhibiting high mechanical properties during load-bearing, with a maximum tensile stress exceeding 1000MPa.

[0025] The embodiments of the present invention disclosed above are merely illustrative of the invention. These embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention.

Claims

1. A composite material pull ring inner core winding molding die, characterized in that: It includes a winding mandrel (1), a segmented module (2), two planar pressure plates (8) and two end pressure plates (9). The winding mandrel (1) includes a winding core (3) and connecting shafts (12) located at both ends of the winding core (3). The segmented module (2) is sleeved on the outside of the winding core (3) and connected to the winding core (3). The segmented module (2) includes multiple segmented molds. The multiple segmented molds are connected in series along the axial direction of the winding mandrel (1) and sleeved on the outside of the winding core (3). A mold groove is formed between two adjacent segmented molds. The two end pressure plates (9) are symmetrically arranged at the left and right ends of the segmented module (2). The two planar pressure plates (8) are symmetrically arranged on the upper and lower sides of the segmented module (2).

2. The composite material pull ring inner core winding molding die according to claim 1, characterized in that: Both ends of the segmented module (2) are provided with fastening rods (5), and one end of the fastening rod (5) passes through multiple segmented modules in sequence and is screwed to a fastening nut (7).

3. The composite material pull ring inner core winding molding die according to claim 2, characterized in that: The rear end of the winding core (3) is provided with a demolding baffle (6). The demolding baffle (6) is connected to one end of the winding core (3) by screws. The two ends of the demolding baffle (6) are respectively in contact with one end of two fastening rods (5).

4. The composite material pull ring inner core winding molding die according to claim 1, characterized in that: The upper and lower sides of the segmented module (2) are provided with multiple pull rods (10). The upper and lower ends of the two end pressure plates (9) are provided with grooves that cooperate with the pull rods (10). The two ends of the pull rods (10) are respectively embedded in and pass through the grooves of the two end pressure plates (9) and screwed to the pull rod nuts (11).

5. The composite material pull ring inner core winding molding die according to claim 1, characterized in that: A positioning key (4) is provided on one side of the winding core (3), and a keyway that cooperates with the positioning key (4) is provided on the inner side of the segmented module (2).

6. The composite material pull ring inner core winding molding die according to claim 1, characterized in that: A positioning groove is provided at the end of the connecting shaft (12) at one end of the winding core (3).

7. A molding method for a composite material pull ring inner core winding molding die as described in claim 1, characterized in that: It includes the following steps: Step 1: Prepare and clean the winding mandrel (1); Step 2: Install the segmented module (2): After sequentially placing multiple segmented modules onto the winding core (3) of the winding mandrel (1), install the fastening rod (5) and fasten it with the fastening nut (7); Step 3: Install the demolding baffle (6) at the tail end of the winding core (3), and connect and fix the winding core (3) and the demolding baffle (6) with screws; Step 4: Clean the mold groove surface of the segmented module (2); Step 5: Hoist the combined mold to the winding machine, and the three-jaw chuck of the winding machine clamps the positioning groove of the connecting shaft (12) at one end of the winding core (3); Step 6: Impregnate epoxy resin with composite fiber and perform winding molding; Step 7: After the winding layer reaches the process thickness, place the end pressure plates (9) at both ends; Step 8: Install flat pressure plates (8) on the upper and lower sides of the segmented module (2), and install tie rods (10) and tie rod nuts (11). Step 9: Remove the combined mold, apply pressure to the two end pressure plates (9) using the pull rod (10), and use C-clamps to tighten and pressurize the two flat pressure plates (8) in multiple steps until the mold is closed. Step 10: Transfer the combined mold to the curing oven for curing. After curing, demold and clean to form a pull ring preform.

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