Carbon fiber composite material casing and manufacturing method thereof

Abstract

The invention relates to the technical field of carbon fiber composite materials, in particular to a carbon fiber composite material casing and a manufacturing method thereof. The casing comprises an upper flange, a lower flange and a main body component, the upper flange and the lower flange are made of metal materials, the main body component is made of carbon fiber composite materials, the main body component is fixed between the upper flange and the lower flange in the mode that carbon fiber prepreg is cured and formed, namely the casing takes the carbon fiber composite materials as a base body, and the metal flanges are adopted to ensure the high-precision requirement. The metal and the composite material are connected in an integrated composite forming mode, the requirements for high precision and high connection strength are met through the design, meanwhile, the requirement for lightweight design is met, and a new solution is provided for manufacturing of the aero-engine case.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon fiber composite materials, and in particular to a carbon fiber composite material casing and a manufacturing method thereof. Background Art

[0002] The casing is a key component of the transmission system in an aircraft engine. It is not only the base of the engine, but also has multiple functions such as protecting the internal components of the engine, transferring and dispersing loads, and providing necessary support. It is also the key to ensuring the stable operation of the engine in extreme environments. The design of the casing often has a complex geometric shape and thin-walled structure to adapt to the requirements of different engine parts and usage environments. The basic feature is a component composed of a cylindrical or conical shell and a support plate. The most important requirements for the casing are high strength and high rigidity to ensure that the casing can remain stable when subjected to huge loads and vibrations, and effectively prevent engine failures caused by structural failures.

[0003] With the continuous advancement of modern aviation technology and the increasing requirements for aircraft performance, lightweight design has gradually become a new trend in the field of casing manufacturing. Lightweight design aims to significantly reduce the overall weight by adopting new materials and optimizing structural design while ensuring high strength and high rigidity of the casing. This change can not only improve fuel efficiency, extend flight distance or increase payload, but also significantly enhance the maneuverability of the aircraft, including improving acceleration, climbing ability and overall control flexibility.

[0004] At present, the casing materials of in-service aircraft are mostly made of metal materials such as high-strength steel, titanium alloy, and high-temperature alloy. However, these traditional materials have certain limitations in terms of lightweighting, such as large weight, easy corrosion, and difficulty in processing and casting. They can no longer meet the higher requirements of modern aircraft engines for high power density and lightweighting. Therefore, the demand for casing materials in the aviation field has gradually developed and changed, and the research and development and application of lightweight materials have become issues that need to be urgently addressed.

[0005] Carbon fiber composites have broad application prospects in key components such as aircraft engine casings due to their high strength, low density and corrosion resistance. By using carbon fiber composites, the weight of the casing can be significantly reduced while maintaining or even improving its strength and rigidity. However, carbon fiber composites also face some technical challenges in practical applications, such as low processing accuracy of the composite materials themselves, immature processing technology, and poor overall casing performance.

[0006] There have been some attempts in the prior art to address the above issues. For example, patent CN116146292A proposes a metal frame casing with a composite material skin, which ensures the rigidity of the structure, but the connection strength of the interface between the composite material skin and the metal frame is insufficient; patent CN115182816A proposes a composite material casing, which is realized by fixing the main body with an independently formed flange. The separately prepared flange avoids the difficulty of the one-piece molding process and the problem of defects at the connection, but the stability of the overall structure cannot be guaranteed by connecting with screw parts.

[0007] In view of this, the present application provides a carbon fiber composite material casing and a manufacturing method thereof to solve the above technical problems. Summary of the invention

[0008] The embodiment of the present invention provides a carbon fiber composite material casing and a manufacturing method thereof, which not only achieves the requirements of high precision and high connection strength, but also meets the needs of lightweight design.

[0009] In a first aspect, an embodiment of the present invention provides a carbon fiber composite casing, comprising an upper flange and a lower flange made of a metal material and a main body component made of a carbon fiber composite material, wherein the main body component is fixed between the upper flange and the lower flange by curing and molding carbon fiber prepreg.

[0010] According to an embodiment of the present invention, the metal material includes at least one of a magnesium alloy and a titanium alloy.

[0011] According to one embodiment of the present invention, the lower end surface of the upper flange and the upper end surface of the lower flange are both provided with grooves, and the upper flange, the lower flange and the main component are all penetrated by through holes, and the through holes are used to insert fasteners to further fix the upper flange, the main component and the lower flange.

[0012] According to one embodiment of the present invention, the grooves are in the form of at least one of vertical lines, diagonal lines, knurling, and triangles.

[0013] In a second aspect, an embodiment of the present invention further provides a method for manufacturing a carbon fiber composite casing device, based on the carbon fiber composite casing described in the above embodiment, comprising:

[0014] Step S1, assembling the metal mold with the upper flange and the lower flange respectively;

[0015] Step S2, cutting the fan-shaped carbon fiber prepreg based on the size of the casing to be manufactured and the fabric laying angle to ensure the fit of the laying;

[0016] Step S3, laying the cut carbon fiber prepreg on the outer surface of the metal mold and the lower end surface of the upper flange and the upper end surface of the lower flange; wherein the carbon fiber prepregs are overlapped;

[0017] Step S4, bagging and pressing the first layer of prepreg that has been laid to remove bubbles between the prepreg and the outer surface of the metal mold, the lower end surface of the upper flange, and the upper end surface of the lower flange;

[0018] Step S5, continue to lay the carbon fiber prepreg layer by layer on the outer surface of the first layer of prepreg according to the preset laying angle and sequence until the thickness of the carbon fiber prepreg reaches the preset thickness; wherein, after each preset number of layers are laid, all current prepregs are bagged to remove bubbles between the prepregs;

[0019] Step S6, curing and molding the paved product in an autoclave, and demoulding the product after curing and molding to obtain a casing blank;

[0020] Step S7, machining the outer surface of the casing blank to obtain a casing product;

[0021] Step S8, applying structural adhesive to the fastener and inserting it into the through hole to further enhance the connection strength between the upper flange, the lower flange and the main component.

[0022] According to one embodiment of the present invention, the metal mold includes an extension rod, an upper end cover and a lower end cover respectively cooperating with the upper and lower ends of the extension rod, and a split combined cone arranged around the extension rod, the upper flange is arranged on the lower surface of the upper end cover, the lower flange is arranged on the upper surface of the lower end cover, and the main body component is arranged on the outer surface of the split combined cone.

[0023] An embodiment of the present invention provides a carbon fiber composite material casing and a manufacturing method thereof, wherein the casing comprises an upper flange and a lower flange made of a metal material and a main component made of a carbon fiber composite material, wherein the main component is fixed between the upper flange and the lower flange by curing and molding a carbon fiber prepreg, that is, the casing uses a carbon fiber composite material as a matrix, adopts a metal flange to ensure high precision requirements, and realizes the connection between the metal and the composite material by an integrated composite molding method. This design not only realizes the requirements of high precision and high connection strength, but also meets the needs of lightweight design, thereby providing a new solution for the manufacture of aircraft engine casings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 is a cross-sectional view of a carbon fiber composite material casing provided by an embodiment of the present invention;

[0026] Figure 2 yes Figure 1 A schematic diagram of the structure of the upper flange in the casing shown;

[0027] Figure 3 yes Figure 1 The schematic diagram of the structure of the lower flange in the casing is shown;

[0028] Figure 4 is a schematic structural diagram of a metal mold provided by an embodiment of the present invention;

[0029] Figure 5 It is a cross-sectional view of a carbon fiber composite material casing and a metal mold provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] As mentioned above, the main technical problems solved in the background technology are how to achieve high-precision requirements for the installation interface, load-bearing strength, and lightweight design. Specifically:

[0032] 1) In the manufacturing process of aircraft engine casings, the high precision of the installation interface is the key to ensure the precise assembly of the casing and other engine components and to ensure the efficient operation of the engine. The precision of metal casings can easily reach a tolerance range of 0.01mm to 0.1mm through traditional cutting, and with the help of precision machining equipment, it can be further reduced to a tolerance level of 0.001mm to 0.01mm, thereby ensuring the accuracy and efficiency of assembly. However, composite materials face many challenges during the processing process. Due to their unique fiber structure, physical properties and processing characteristics, such as differences in fiber arrangement and distribution, resulting in different surface hardness and strength; weak interlayer bonding strength, easy to produce defects such as delamination and peeling during processing; easy to produce thermal effects during processing, resulting in material deformation and processing errors. Therefore, the processing accuracy of composite materials is often difficult to match that of metal materials. Generally speaking, the tolerance of composite materials is controlled at around 0.2mm, which is much lower than the processing accuracy of metal materials.

[0033] This difference in tolerance levels may not only cause the casing to not fit tightly with other engine components during assembly, affecting the overall performance and operating efficiency of the engine. It may also lead to high costs when pursuing composite materials to achieve the same precision as metal materials. For example, more sophisticated processing equipment, more complex processing technology and more stringent processing environment, as well as more post-processing steps are required to correct processing errors, which significantly increases production costs and processing cycles.

[0034] Therefore, how to improve the processing accuracy of carbon fiber composite materials while maintaining their lightweight advantages to meet the high-precision requirements of the installation interface has become one of the technical problems that the present invention needs to solve.

[0035] 2) As a key load-bearing component, the casing needs to withstand huge loads and vibrations during engine operation. It not only withstands various mechanical stresses and thermal stresses from the engine, but also additional stresses from the external environment such as airflow and temperature. The cylindrical or conical shell of the casing, the mounting edge of the casing and its connection area, and the bearing fulcrum are constructed as the main load-bearing areas. These areas bear extremely high loads during engine operation. At the same time, due to the complex geometric structure of the casing, its steps, transition areas, and bolt holes on the flange, these parts are prone to deformation and stress concentration under the action of cyclic loads, thereby affecting the overall strength and durability of the casing.

[0036] Therefore, how to use high-performance carbon fiber composite materials to achieve a lightweight design of the casing while ensuring its load-bearing capacity and fatigue resistance, and having excellent high load-bearing strength ability, becomes one of the technical problems that the present invention needs to solve.

[0037] 3) Lightweight design is an important trend in the manufacture of modern aircraft engine casings, aiming to reduce the overall weight of the engine and improve fuel efficiency and flight performance. Carbon fiber composite materials have significant advantages in lightweight design due to their high strength and low density. However, to fully utilize this advantage, it is necessary to solve the poor processing accuracy of carbon fiber composite materials in the above-mentioned medium and ensure the ability to withstand high load strength. Carbon fiber composite materials are used to reduce weight and achieve high-precision requirements for the casing installation interface, while ensuring that the design of the load-bearing area and stress concentration points meets the reliability and safety requirements of engine operation.

[0038] In order to solve the above technical problems, Figure 1 As shown, an embodiment of the present invention provides a carbon fiber composite casing, including an upper flange 1 and a lower flange 2 made of metal material and a main body component 3 made of carbon fiber composite material, and the main body component 3 is fixed between the upper flange 1 and the lower flange 2 by curing and molding carbon fiber prepreg.

[0039] In this embodiment, the casing uses carbon fiber composite material as the matrix, adopts metal flanges to ensure high precision requirements, and realizes the connection between metal and composite materials through integrated composite molding. This design not only achieves the requirements of high precision and high connection strength, but also meets the needs of lightweight design, providing a new solution for the manufacture of aircraft engine casings.

[0040] In one embodiment of the present invention, the metal material includes at least one of a magnesium alloy and a titanium alloy.

[0041] In this embodiment, the metal flange is made of magnesium alloy light and high-strength metal, and high-precision dimensions such as assembly structure, interface size, and threaded holes are achieved through fine machining. At the same time, key structural features such as threaded holes and bearing bushings can be obtained on the metal flange through machining to ensure the functionality and precision requirements of the connection and assembly parts. The machining of metal materials is relatively simple, which reduces production defects during the machining process and avoids the problems of reduced fiber damage strength after machining, poor machining accuracy, and many production defects in composite flanges.

[0042] like Figure 2 and 3 As shown, in one embodiment of the present invention, the lower end surface of the upper flange 1 and the upper end surface of the lower flange 2 are both provided with a groove 4, and the upper flange 1, the lower flange 2 and the main component 3 are all penetrated by a through hole 5, and the through hole 5 is used to insert a fastener to further fix the upper flange 1, the main component 3 and the lower flange 2.

[0043] In one embodiment of the present invention, the groove 4 has at least one of vertical lines, diagonal lines, knurling and triangles.

[0044] In this embodiment, the metal flange is designed with grooves and pin holes. The grooves can be designed in the form of vertical lines, twill lines, knurling, triangles, etc., to increase the contact area between the metal and the composite material, and then enhance the connection strength between the interfaces after composite. The pins penetrate the metal and composite materials to further improve the strength of the connection parts and ensure the overall performance of the casing when under load.

[0045] In addition, an embodiment of the present invention further provides a method for manufacturing a carbon fiber composite casing, based on the carbon fiber composite casing mentioned in the above embodiment, comprising:

[0046] Step S1, assembling the metal mold 6 with the upper flange 1 and the lower flange 2 respectively;

[0047] Step S2, cutting the fan-shaped carbon fiber prepreg based on the size of the casing to be manufactured and the fabric laying angle to ensure the fit of the laying;

[0048] Step S3, laying the cut carbon fiber prepreg on the outer surface of the metal mold 6 and the lower end surface of the upper flange 1 and the upper end surface of the lower flange 2; wherein the carbon fiber prepregs are overlapped;

[0049] Step S4, bagging and pressing the first layer of prepreg that has been laid to remove bubbles between the prepreg and the outer surface of the metal mold 6, the lower end surface of the upper flange 1, and the upper end surface of the lower flange 2;

[0050] Step S5, continue to lay the carbon fiber prepreg layer by layer on the outer surface of the first layer of prepreg according to the preset laying angle and sequence until the thickness of the carbon fiber prepreg reaches the preset thickness; wherein, after each preset number of layers are laid, all current prepregs are bagged to remove bubbles between the prepregs;

[0051] Step S6, curing and molding the paved product in an autoclave, and demoulding the product after curing and molding to obtain a casing blank;

[0052] Step S7, machining the outer surface of the casing blank to obtain a casing product;

[0053] Step S8, apply structural adhesive to the fastener and insert it into the through hole 5 to further enhance the connection strength between the upper flange 1, the lower flange 2 and the main component 3.

[0054] It can be known that during the composite molding process, the prepreg extends from the groove on the metal flange surface to the shell part, and then to the groove on the metal flange at the other end, realizing the laying of continuous fabric, maximizing the strength, and achieving close bonding between materials. The groove on the metal flange effectively increases the contact area between the composite material and the metal flange, further enhancing the connection strength between different dielectric materials, and reinforcing the turning point from the metal flange to the composite shell to prevent stress concentration from causing damage to the receiver.

[0055] Select high-strength and high-modulus carbon fiber materials, optimize the layup scheme of carbon fiber composite materials through simulation design, and reasonably design the layup angle and sequence to ensure that the composite part can reduce weight while meeting the strength and rigidity requirements, thus achieving lightweight design.

[0056] Prepreg cutting is required in composite material molding. To ensure the structural strength of the carbon fiber composite material in the middle of the casing, wrinkles, stacking, collapse and other defects must be avoided during the laying process, and the bubbles accumulated between the fabrics must be reduced during the molding process. For this reason, the paved area is flattened and paved with fan-shaped prepreg. Considering the special-shaped geometric structure and the upper and lower ends extending to the groove area of ​​the metal flange surface, the fan-shaped expansion diagram is cut and the margin is designed for overlapping transition. In the paving process, a bag pressing process is carried out after the first layer is laid on the mold surface, and then a bag pressing is carried out every 4 to 5 layers, in order to minimize the bubbles accumulated between the prepreg layers.

[0057] like Figure 4 and 5 As shown, in one embodiment of the present invention, the metal mold 6 includes an extension rod 61, an upper end cover 62 and a lower end cover 63 respectively matched with the upper and lower ends of the extension rod 61, and a split combined cone 64 arranged around the extension rod 61, the upper flange 1 is arranged on the lower surface of the upper end cover 62, the lower flange 2 is arranged on the upper surface of the lower end cover 63, and the main body component 3 is arranged on the outer surface of the split combined cone 64.

[0058] In this embodiment, the metal mold 6 can be designed as a four-petal combination mold, which consists of an extension rod 61, a limiting tool (i.e., an upper end cover 62 and a lower end cover 63), and a four-petal combination cone mold (i.e., a split combination cone 64). The four-petal mold is fastened by bolts to form an integral cone mold, and is assembled with the extension rod and the upper tool. The extension rod has a threaded hole corresponding to the threaded hole portion of the metal flange. Through this mold design, the prepreg paving can be extended from the metal flange end to the mold surface, ensuring high-strength integrated molding between the carbon fiber composite material and the metal flange. After the product is formed, the mold can be easily disassembled, the demoulding process is optimized, and the process operation is simplified.

[0059] In summary, the casing provided by the present invention adopts an integrated molding method of carbon fiber composite materials and magnesium alloy flanges to achieve lightweight design while ensuring high precision and high strength. The high precision requirements are achieved through fine processing of the flange part, avoiding the defects of insufficient precision and difficult processing of the composite casing. The high-precision requirements of the installation interface of the composite casing are realized by the metal flange casing, avoiding the problem that the composite flange is difficult to process and has low processing accuracy. The connection strength between the metal and the composite is guaranteed by an integrated composite method, the load is borne by the integral metal flange end, and the metal connection of the composite material is reinforced to achieve the load-bearing strength requirement, and the middle section of the carbon fiber composite shell realizes a lightweight design. In other words, the present invention realizes the preparation of the casing by the separately prepared metal flange and carbon fiber composite integrated molding, which not only ensures the high-precision installation and assembly of the metal flange part, but also effectively improves the connection strength between the composite material and the metal flange. While meeting the strength and rigidity requirements of the aircraft engine casing, a weight reduction of about 10% is achieved.

[0060] In order to better understand the present invention, the content of the present invention is further explained in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0061] In the embodiment, the carbon fiber prepreg is T800 carbon fiber prepreg, the high temperature curing epoxy resin system, the magnesium alloy metal flange, and the mold is a four-petal metal mold.

[0062] The specific molding process steps are as follows:

[0063] Step S1, the four-petal metal mold is fastened by screws and surface treated to ensure that the surface is smooth and defect-free, the upper metal flange (i.e., upper flange 1) and the lower metal flange (i.e., lower flange 2) are assembled with the mold, and the limiting tooling is assembled;

[0064] Step S2, cutting the carbon fiber prepreg according to the size of the casing, taking into account the structural characteristics of the casing, adopting a planar unfolding method to design the cutting size of the prepreg, and cutting the fan-shaped prepreg by a cutting machine in four directions of 0°, ±45°, and 90°;

[0065] Step S3, laying the cut fan-shaped carbon fiber prepreg on the metal mold and the metal flange. The metal flange is designed with a groove. The fan-shaped prepreg starts to lay from the upper metal flange part, gradually transitions to the groove area and then to the surface of the metal mold, and extends to the lower metal groove and flange. The prepregs are overlapped and appropriately cut as needed to ensure the adhesion and consistency of the laying.

[0066] Step S4: After the first layer of prepreg is laid, a bag pressing is performed. The bag pressing process removes bubbles on the mold surface and improves the molding quality.

[0067] Step S5, continue to lay the carbon fiber prepreg, and lay it layer by layer according to the ply sequence designed by simulation until the required thickness is reached. The ply sequence is simulated and calculated according to the structural dimensions and performance requirements of the product; wherein, bag pressing is performed after each set of four layers is completed, in order to remove the bubbles between the prepreg layers, so as to avoid the bubbles being unable to be effectively removed after complete laying;

[0068] Step S6: After the paving is completed, the autoclave molding process is carried out, sealing strips, demoulding cloth, breathable felt, vacuum bag film are laid, valves are installed and connected to the vacuum system, the air is evacuated to negative pressure, and heating and pressurizing are performed for curing. In this embodiment, the temperature is set to 130℃ for 30 minutes, 180℃ for 3 hours, the heating rate is 40℃ / h, and the pressure is 600KPa; after curing and molding, the demoulding operation is performed, and the four-petal metal mold is disassembled from the metal flange at the lower end of the casing to obtain the cured casing blank;

[0069] Step S7, obtaining a casing product by machining the outer surface of the middle section composite material;

[0070] Step S8, apply structural adhesive to the pins (i.e. fasteners) and insert them into the pin holes between the metal flange and the carbon fiber composite material to further enhance the connection strength between the metal flange and the composite material and ensure the overall strength and stability of the casing.

[0071] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise a ..." do not exclude the presence of other identical factors in the process, method, article or device including the elements.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A carbon fiber composite material casing, characterized in that: The invention comprises an upper flange and a lower flange made of metal materials and a main body component made of carbon fiber composite material. The main body component is fixed between the upper flange and the lower flange by curing and molding carbon fiber prepreg.

2. The carbon fiber composite material casing according to claim 1, characterized in that: The metal material includes at least one of a magnesium alloy and a titanium alloy.

3. The carbon fiber composite material casing according to claim 1, characterized in that: The lower end surface of the upper flange and the upper end surface of the lower flange are both provided with grooves, and the upper flange, the lower flange and the main component are all penetrated by through holes, and the through holes are used to insert fasteners to further fix the upper flange, the main component and the lower flange.

4. The carbon fiber composite material casing according to claim 3, characterized in that: The grooves may be in a form of at least one of vertical lines, diagonal lines, knurling, and triangles.

5. A method for manufacturing a carbon fiber composite material casing, characterized in that: The carbon fiber composite material casing according to claim 3 comprises: Step S1, assembling the metal mold with the upper flange and the lower flange respectively; Step S2, cutting the fan-shaped carbon fiber prepreg based on the size of the casing to be manufactured and the fabric laying angle to ensure the fit of the laying; Step S3, laying the cut carbon fiber prepreg on the outer surface of the metal mold and the lower end surface of the upper flange and the upper end surface of the lower flange; wherein the carbon fiber prepregs are overlapped; Step S4, bagging and pressing the first layer of prepreg that has been laid to remove bubbles between the prepreg and the outer surface of the metal mold, the lower end surface of the upper flange, and the upper end surface of the lower flange; Step S5, continue to lay the carbon fiber prepreg layer by layer on the outer surface of the first layer of prepreg according to the preset laying angle and sequence until the thickness of the carbon fiber prepreg reaches the preset thickness; wherein, after each preset number of layers are laid, all current prepregs are bagged to remove bubbles between the prepregs; Step S6, curing and molding the paved product in an autoclave, and demoulding the product after curing and molding to obtain a casing blank; Step S7, machining the outer surface of the casing blank to obtain a casing product; Step S8, applying structural adhesive to the fastener and inserting it into the through hole to further enhance the connection strength between the upper flange, the lower flange and the main component.

6. The method for manufacturing a carbon fiber composite material casing according to claim 5, characterized in that: The metal mold includes an extension rod, an upper end cover and a lower end cover respectively matched with the upper and lower ends of the extension rod, and a split combined cone arranged around the extension rod, the upper flange is arranged on the lower surface of the upper end cover, the lower flange is arranged on the upper surface of the lower end cover, and the main body component is arranged on the outer surface of the split combined cone.

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