Integral forming mold and method for water-resistant thermoplastic composite rotor

Abstract

The invention relates to the technical field of composite material propeller rotor forming, in particular to an integral forming mold and method for a water-resistant thermoplastic composite material rotor, and the mold comprises a blade pressing mold and an integral mold; the integral mold comprises a female mold and a male mold, the female mold and the male mold define a third cavity for placing a rotor core, a second cavity surrounding the third cavity and a plurality of first cavities arranged on the outer side of the second cavity at intervals, the third cavity is communicated with the second cavity, and the second cavity is communicated with the first cavities; a positioning groove for fixing the rotor core is formed in the center of the bottom surface of the third cavity; a pressing plate is further embedded in the male die, the plane where the bottom of the pressing plate is located coincides with the top face of the third cavity, and a screw hole penetrates through the upper surface of the pressing plate. Wherein a forming cavity of the blade pressing mold comprises blade sections which are the same as the first cavities in shape and connecting sections arranged at one ends of the blade sections; and a sprue gate is further formed in the upper surface of the male die and communicates with the second cavity through a pouring pipeline.

Description

Technical Field

[0001] The invention relates to the technical field of composite propeller rotor molding, and in particular to an integral molding die and method for a water-resistant thermoplastic composite rotor. Background Art

[0002] As an important component of underwater vehicles, propellers can convert the torque output by the power system of the vehicle during navigation into the power required for navigation, so that the vehicle can sail at the required speed. The expanded application of composite materials in propellers will play a huge role in vibration reduction, weight reduction, noise reduction and corrosion resistance of vehicles.

[0003] The existing thermosetting composite propeller rotor hub and rotor blades are mostly prepared by combining "adhesion + local bonding reinforcement", mechanical structure connection, "adhesion + mechanical connection", or by thermosetting prepreg integral layer molding. However, the above molding methods will form a potential stress concentration area at the connection position of the rotor blade and the hub. At the same time, the overall molding process has the concept of layers, and the interlayer strength is low, which will cause the connection position to degrade and fatigue damage to expand under the action of periodic loads and long-term immersion in seawater. In severe cases, it will cause interlayer delamination or matrix cracking at the connection position, resulting in reduced stiffness and strength of the product, seriously affecting its service life. In addition, compared with thermosetting composite rotors, high-performance thermoplastic composite rotors have the characteristics of good toughness, low moisture absorption rate, secondary molding, and intelligent manufacturing. Therefore, the development of high-performance thermoplastic composite materials for large-load, high-rigidity, and marine environment-resistant propeller rotors can provide efficient and reliable propulsion guarantees for a new generation of long-range, high-speed, and highly stealthy heavy-duty aircraft.

[0004] Therefore, in view of the above problems, the present invention urgently needs to provide an integral molding die and method for a water-resistant thermoplastic composite rotor. Summary of the invention

[0005] The technical problem solved by the present invention is to provide an integral molding mold and method for a water-resistant thermoplastic composite rotor. The design of the hub and blades is prepared by an injection molding process to solve the problems of low connection strength between the blades, hub and rotor core in the prior art. The strength of the connection between the blades and the hub of the rotor and the overall stiffness of the rotor can be effectively guaranteed, while the seawater resistance is improved, effectively ensuring the service life of the rotor for underwater vehicles sailing in water for a long time.

[0006] The present invention provides an integral forming mold for a water-resistant thermoplastic composite rotor, comprising a blade pressing mold and an integral mold; the integral mold comprises a female mold and a male mold, the female mold and the male mold are surrounded by a third cavity for placing a rotor core, a second cavity surrounded outside the third cavity, and a plurality of first cavities spaced outside the second cavity, the third cavity is connected to the second cavity, and the second cavity is connected to each of the first cavities; A positioning groove for fixing the rotor core is provided at the center of the bottom surface of the third cavity; A pressing plate is also embedded in the male mold, the plane where the bottom of the pressing plate is located coincides with the top surface of the third cavity, and a screw hole for screwing with the rotor core is penetrated through the upper surface of the pressing plate; Wherein, the forming cavity of the blade pressing mold comprises a blade segment having the same shape as each first cavity and a connecting segment arranged at one end of the blade segment, and the cross-sectional area of ​​the connecting segment away from the end of the blade segment is larger than the cross-sectional area of ​​the other end of the connecting segment; The upper surface of the male mold is also provided with a pouring port, which is communicated with the second cavity through a pouring pipe.

[0007] Preferably, the cross-sectional area of ​​the connecting section of the forming cavity of the blade pressing mold at one end away from the blade segment is 3.5 times the cross-sectional area of ​​the other end of the connecting section, and the length of the connecting section is 15-20 mm.

[0008] Preferably, the bottom of the female mold is also provided with a plurality of ejection holes at intervals, each of which has a size of φ6, and an ejector pin is tightly installed in each ejection hole; during the pouring process, the upper surface of the ejector pin is flush with the bottom of the female mold; after molding, the ejector pin passes through the ejection hole to eject the rotor from the mold.

[0009] The present invention also provides an integral forming method of a water-resistant thermoplastic composite rotor based on an integral forming mold of the water-resistant thermoplastic composite rotor, comprising the following steps: 1) Laying a certain thickness of thermoplastic resin in the molding cavity of the blade pressing mold, pre-pressing, and demolding to obtain a blade preform; 2) placing the blade preform in the first cavity of the female mold so that one end of the blade preform extends into the second cavity; 3) Install the rotor core in the third cavity by engaging the positioning groove with the protrusion below the rotor core, and connect the pressure plate and the rotor core with the fastening screws; 4) Place the male mold coaxially on top of the female mold and press it tightly, and pour into the second cavity through the pouring port; 5) After heating, pressurizing and keeping the whole mold warm, demoulding; 6) Mechanically processing the rotor core to obtain a water-resistant thermoplastic composite rotor.

[0010] Preferably, the blade preform comprises a blade segment located in the first cavity and a connecting segment located in the second cavity, the cross-sectional area of ​​the connecting segment away from the blade segment is 3.5 times the cross-sectional area of ​​the other end of the connecting segment, and the length of the connecting segment is 15-20 mm.

[0011] Preferably, the material of the blade preform is T700 continuous carbon fiber reinforced high-performance thermoplastic resin using polyetheretherketone or polyaryletherketone as a matrix, and the material of the resin injected into the second cavity is T700 chopped fiber reinforced thermoplastic resin using polyetheretherketone or polyaryletherketone as a matrix.

[0012] Preferably, the side surface of the rotor core has a plurality of groups of continuously arranged staggered grooves distributed in a diamond shape, and the material of the rotor core is TC9 titanium alloy.

[0013] Preferably, the bottom of the female mold is also provided with a plurality of ejection holes at intervals, each of which has a size of φ6, and an ejector pin is tightly installed in each ejection hole; during the pouring process, the upper surface of the ejector pin is flush with the bottom of the female mold; after heating, pressurizing and heat preservation, the male mold is removed, and then the fastening screws and the pressure plate are removed, and the ejector pin passes through the ejection hole to eject the rotor from the mold.

[0014] Preferably, in step 6), the mechanical processing of the rotor core includes coaxially drilling a hole in the rotor core and providing a spline inside the through hole.

[0015] Preferably, in step 4), the temperature of the injected resin is 400±10° C.; in step 5), the curing process is to heat the mold to 230-260° C. and keep the temperature for 1 hour.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides an integral forming mold and method for a water-resistant thermoplastic composite rotor. After a blade preform is pre-prepared by means of a compression molding technology, the blade preform is fixed in a second cavity by means of spot welding, thereby ensuring the coaxiality between the blade and the hub; and the inner side of the blade preform is designed to be an inverted trapezoid, thereby improving the connection strength between the blade root and the hub; then, through the injection molding process, the integral forming of the blade, the hub and the rotor core is achieved. The mold of the present invention is easy to operate and has high manufacturing precision, and can effectively ensure the strength of the connection between the rotor blade and the hub and the overall stiffness of the product, while also being able to improve the product's seawater resistance, thereby effectively ensuring the service life of the rotor for underwater vehicles during long navigation in water. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram (vertical cross-sectional view) of step 4) in an embodiment of the present invention; Figure 2 is a structural schematic diagram (vertical cross-sectional view) of the integral mold according to an embodiment of the present invention; Figure 3 is a schematic structural diagram (stereoscopic diagram) of the female mold according to an embodiment of the present invention; Figure 4 is a structural schematic diagram (stereoscopic diagram) of a water-resistant thermoplastic composite rotor according to an embodiment of the present invention; Figure 5 It is an operation flow chart of the integral molding method of the water-resistant thermoplastic composite rotor described in an embodiment of the present invention.

[0018] Among them: 1. blade preform; 2. blade hub; 3. rotor core; 4. male mold; 401. pouring port; 5. female mold; 7. positioning groove; 8. pressure plate; 801. screw hole; 9. fastening screw; 10. ejection hole; 11. first cavity; 14. protrusion; 15. blade. DETAILED DESCRIPTION

[0019] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solution of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, this embodiment provides an integral molding die for a water-resistant thermoplastic composite rotor, comprising a blade pressing die and an integral die; the integral die comprises a female die 5 and a male die 4, the female die 5 and the male die 4 surround a third cavity for placing a rotor core 3, a second cavity surrounded outside the third cavity, and a plurality of first cavities 11 spaced apart outside the second cavity, the third cavity is connected to the second cavity, and the second cavity is connected to each of the first cavities 11; A positioning groove 7 for positioning the rotor core 3 is provided at the bottom center of the female mold 5; A pressing plate 8 is also provided in the male mold 4, and the plane where the bottom of the pressing plate 8 is located coincides with the top surface of the third cavity; The forming cavity of the blade pressing mold includes a blade segment having the same shape as each first cavity 11 and a connecting segment having an inverted trapezoidal cross section.

[0021] The present invention provides an integral forming mold and method for a water-resistant thermoplastic composite rotor. After a blade preform is pre-prepared by means of a compression molding technology, the blade preform is fixed in a second cavity by means of spot welding, thereby ensuring the coaxiality between the blade and the hub; and the inner side of the blade preform is designed to be an inverted trapezoid, thereby improving the connection strength between the blade root and the hub; then, through the injection molding process, the integral forming of the blade, the hub and the rotor core is achieved. The mold of the present invention is easy to operate and has high manufacturing precision, and can effectively ensure the strength of the connection between the rotor blade and the hub and the overall stiffness of the product, while also being able to improve the product's seawater resistance, thereby effectively ensuring the service life of the rotor for underwater vehicles during long navigation in water.

[0022] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, the angle between the upper surface of the connecting section of the blade pressing mold forming cavity and the horizontal plane is 30°, and the length of the connecting section is 15-20 mm.

[0023] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, a plurality of ejection holes 10 are provided at intervals at the bottom of the female mold 5, and the model of each ejection hole 10 is φ6.

[0024] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, the present invention provides an integral molding method of a water-resistant thermoplastic composite rotor based on an integral molding die of a water-resistant thermoplastic composite rotor, comprising the following steps: 1) Laying a certain thickness of thermoplastic resin in the molding cavity of the blade pressing mold, pre-pressing, and demolding to obtain a blade preform 1; 2) fixing the blade preform 1 in the first cavity 11 of the female mold 5 so that the inner side of the blade preform 1 extends into the second cavity; 3) The rotor core 3 is installed in the third cavity by the cooperation between the positioning groove 7 and the protrusion 14 below the rotor core 3, and the pressure plate 8 and the rotor core 3 are connected by the fastening screws 9; 4) Place the male mold 4 coaxially above the female mold 5 and press it tightly, and inject resin into the second cavity; 5) After heating, pressurizing and keeping the whole mold warm, demoulding; 6) Mechanically process the rotor core 3 to obtain a water-resistant thermoplastic composite rotor.

[0025] Wherein, in step 3), before installing the rotor core 3, a glass fiber epoxy prepreg fabric protective layer with a thickness of 0.3 mm is randomly formed on its surface.

[0026] The present invention provides an integral forming mold and method for a water-resistant thermoplastic composite rotor. After a blade preform is pre-prepared by means of a compression molding technology, the blade preform is fixed in a second cavity by means of spot welding, thereby ensuring the coaxiality between the blade and the hub; and the inner side of the blade preform is designed to be an inverted trapezoid, thereby improving the connection strength between the blade root and the hub; then, through the injection molding process, the integral forming of the blade, the hub and the rotor core is achieved. The mold of the present invention is easy to operate and has high manufacturing precision, and can effectively ensure the strength of the connection between the rotor blade and the hub and the overall stiffness of the product, while also being able to improve the product's seawater resistance, thereby effectively ensuring the service life of the rotor for underwater vehicles during long navigation in water.

[0027] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, the cross section of the portion of the blade preform 1 extending into the second cavity is an inverted trapezoid, the angle between its upper surface and the horizontal plane is 30°, and the length of this portion is 15-20 mm.

[0028] In this embodiment, the blade preform 1 can be fixed in the first cavity 11 of the female mold 5 by spot welding, and the two welded ends are an end of the blade preform 1 close to the rotor core 3 and the epoxy glass fiber composite material layer covering the outer surface of the rotor core 3 .

[0029] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, the material of the blade preform 1 is T700 continuous carbon fiber reinforced high-performance thermoplastic resin using polyetheretherketone or polyaryletherketone as a matrix, and the material of the resin injected into the second cavity is T700 chopped fiber reinforced thermoplastic resin using polyetheretherketone or polyaryletherketone as a matrix; the side surface of the rotor core 3 is distributed in a diamond shape with multiple groups of continuously arranged staggered grooves with a depth of 1-2mm, and the material of the rotor core 3 is TC9 titanium alloy.

[0030] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, a plurality of ejection holes 10 are provided at intervals at the bottom of the female mold 5 ; during demoulding, the male mold 4 is removed, and then the fastening screws 9 and the pressing plate 8 are removed, and then the female mold 5 is removed through the ejection holes 10 .

[0031] like Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, the machining of the rotor core 3 includes coaxially drilling a hole in the rotor core 3 and providing a spline inside the through hole.

[0032] In this embodiment, in step 4), the temperature of the injected resin is 400±10°C; in step 5), the curing process is to heat the mold to 230-260°C and keep it warm for 1 hour.

[0033] The present invention also provides an embodiment: Among them, the outer diameter of the blade 2 is 90±0.5mm, the maximum length of a single blade 15 is 88-90mm, the circumference of the outer end surface of the blade 15 is 200mm, and the maximum width of the blade 15 is 4mm; the outer diameter of the composite rotor is 267-269mm, and the height is 68-70mm; the diameter of the rotor core 3 is 60mm, and a pre-cured glass fiber fabric reinforced epoxy prepreg with a thickness of 0.3mm is provided between the rotor core 3 and the blade 2 to isolate the metal (rotor core 3) and the composite material (blade 2) from the potential corrosion effect generated in seawater; the blade 2 part is prepared by injection molding process using T700 chopped fiber reinforced thermoplastic resin with polyetheretherketone or polyaryletherketone as the matrix. The temperature of the chopped material during injection molding is 400±10℃, the total injection amount of the short material is 400g, the overall molding mold temperature is 230-260℃, and the insulation time is 1h after the injection is completed; The integral forming method of the composite rotor comprises the following steps: 1) Laying a certain thickness of thermoplastic resin in the molding cavity of the blade pressing mold, pre-pressing, and demolding to obtain a blade preform 1; 2) placing the blade preform 1 into the first cavity 11 of the female mold 5 so that one end of the blade preform 1 extends into the second cavity; 3) The rotor core 3 is installed in the third cavity by the cooperation between the positioning groove 7 and the protrusion 14 below the rotor core 3, and the pressure plate 8 and the rotor core 3 are connected by the fastening screws 9; 4) placing the male mold 4 coaxially above the female mold 5 and pressing it tightly, and pouring resin into the second cavity through the pouring port 401; 5) After heating, pressurizing and keeping the whole mold warm, demoulding; 6) Mechanically process the rotor core 3 to obtain a water-resistant thermoplastic composite rotor.

[0034] The composite rotor prepared in this embodiment was subjected to a 180-day seawater immersion challenge after installation. After the test, the prototype was weighed, and the water absorption rate was measured to be 0.4-0.6%. A load of 1000N was applied to the blade 15 at a center position 100mm away from the center of the rotor in a direction parallel to the rotor axis. The test showed that the maximum deformation of the middle of the outer end of the blade 15 was 0.8mm.

[0035] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. An integral forming die for a water-resistant thermoplastic composite rotor, characterized in that: The invention comprises a blade pressing mold and an integral mold; the integral mold comprises a female mold (5) and a male mold (4); the female mold (5) and the male mold (4) are arranged to form a third cavity for accommodating a rotor core (3), a second cavity arranged outside the third cavity, and a plurality of first cavities (11) arranged at intervals outside the second cavity; the third cavity is connected to the second cavity, and the second cavity is connected to each of the first cavities (11); A positioning groove (7) for fixing the rotor core (3) is provided at the center of the bottom surface of the third cavity; A pressing plate (8) is also embedded in the male mold (4), the plane where the bottom of the pressing plate (8) is located coincides with the top surface of the third cavity, and a screw hole (801) for screwing to the rotor core (3) is penetrated through the upper surface of the pressing plate (8); The forming cavity of the blade pressing mold comprises a blade segment having the same shape as each first cavity (11) and a connecting segment arranged at one end of the blade segment, and the cross-sectional area of ​​the connecting segment away from the end of the blade segment is larger than the cross-sectional area of ​​the other end of the connecting segment; The upper surface of the male mold (4) is also provided with a pouring port (401), and the pouring port (401) is connected to the second cavity through a pouring pipe.

2. The integral forming die of the water-resistant thermoplastic composite rotor according to claim 1, characterized in that: The cross-sectional area of ​​the connecting section of the blade pressing mold molding cavity away from the blade segment is 3.5 times the cross-sectional area of ​​the other end of the connecting section, and the length of the connecting section is 15-20 mm.

3. The integral forming die of the water-resistant thermoplastic composite rotor according to claim 2, characterized in that: The bottom of the female mold (5) is also provided with a plurality of ejection holes (10) at intervals, each ejection hole (10) having a size of φ6, and an ejector pin is tightly mounted in each ejection hole (10); during the pouring process, the upper surface of the ejector pin is flush with the bottom of the female mold (5); after molding is completed, the ejector pin passes through the ejection hole (10) to eject the rotor from the mold.

4. A method for integrally forming a water-resistant thermoplastic composite rotor based on the integrally forming mold of the water-resistant thermoplastic composite rotor as claimed in any one of claims 1 to 3, characterized in that: The steps include: 1) laying a certain thickness of thermoplastic resin in the molding cavity of a blade pressing mold, pre-pressing, and demolding to obtain a blade preform (1); 2) placing the blade preform (1) in the first cavity (11) of the female mold (5) in accordance with the mold, so that one end of the blade preform (1) extends into the second cavity; 3) installing the rotor core (3) in the third cavity by engaging the positioning groove (7) with the protrusion (14) below the rotor core (3), and connecting the pressure plate (8) and the rotor core (3) using the fastening screws (9); 4) placing the male mold (4) coaxially above the female mold (5) and pressing it tightly, and pouring resin into the second cavity through the pouring port (401); 5) After heating, pressurizing and keeping the whole mold warm, demoulding; 6) Mechanically processing the rotor core (3) to obtain a water-resistant thermoplastic composite rotor.

5. The integral molding method of the water-resistant thermoplastic composite rotor according to claim 4, characterized in that: The blade preform (1) comprises a blade segment located in the first cavity (11) and a connecting segment located in the second cavity, the cross-sectional area of ​​the connecting segment at one end away from the blade segment is 3.5 times the cross-sectional area of ​​the other end of the connecting segment, and the length of the connecting segment is 15-20 mm.

6. The integral molding method of the water-resistant thermoplastic composite rotor according to claim 5, characterized in that: The material of the blade preform (1) is T700 continuous carbon fiber reinforced high-performance thermoplastic resin using polyetheretherketone or polyaryletherketone as a matrix, and the material of the resin injected into the second cavity is T700 chopped fiber reinforced thermoplastic resin using polyetheretherketone or polyaryletherketone as a matrix.

7. The integral molding method of the water-resistant thermoplastic composite rotor according to claim 6, characterized in that: The side surface of the rotor core (3) is provided with a plurality of groups of continuously arranged staggered grooves distributed in a rhombus shape, and the material of the rotor core (3) is TC9 titanium alloy.

8. The integral molding method of the water-resistant thermoplastic composite rotor according to claim 7, characterized in that: The bottom of the female mold (5) is also provided with a plurality of ejection holes (10) at intervals, each of which has a size of φ6, and an ejector pin is tightly mounted in each of the ejection holes (10); during the pouring process, the upper surface of the ejector pin is flush with the bottom of the female mold (5); after heating, pressurizing and heat preservation, the male mold (4) is removed, and then the fastening screws (9) and the pressure plate (8) are removed, and the ejector pin passes through the ejection hole (10) to eject the rotor out of the mold.

9. The integral molding method of the water-resistant thermoplastic composite rotor according to claim 8, characterized in that: In step 6), the mechanical processing of the rotor core (3) includes coaxially opening a hole in the rotor core (3) and providing a spline inside the through hole.

10. The integral molding method of the water-resistant thermoplastic composite rotor according to claim 9, characterized in that: In step 4), the temperature of the injected resin is 400±10°C; in step 5), the curing process is to heat the mold to 230-260°C and keep it warm for 1 hour.

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