Metal-carbon fiber composite railway axle and its manufacturing method

Abstract

This invention discloses a metal-carbon fiber composite railway axle and its manufacturing method. The metal-carbon fiber composite railway axle includes a main shaft, a threaded inner tube, an axle end sleeve, and a compression cap. The threaded inner tube is disposed inside the main shaft, and the axle end sleeves are symmetrically disposed on both sides of the main shaft. The compression caps are disposed at both ends of the axle end sleeve and engage with the threaded inner tube. The main shaft includes a main shaft body and an extension shaft body, with the extension shaft bodies symmetrically disposed at both ends of the main shaft body. The diameter of the extension shaft body is smaller than that of the main shaft body. A transition shoulder is provided between the main shaft body and the extension shaft body. A bearing seat with a tapered transition is provided on one side of the outer wall of the axle end sleeve for bearing positioning. A wheel seat is provided on the other side of the outer wall of the axle end sleeve for wheel positioning. A connecting shoulder extends from one end of the axle end sleeve. This invention improves tensile strength and corrosion resistance while reducing weight, effectively increases the contact area, avoids axial movement of the main shaft, and effectively improves structural safety performance.

Description

Technical Field

[0001] This invention belongs to the field of railway axle manufacturing technology, and particularly relates to a metal carbon fiber composite structure railway axle and its manufacturing method. Background Technology

[0002] Railway axles are a crucial structure connecting trains and wheels. Existing solid steel axles in rail vehicles have the following drawbacks: excessive weight (a typical φ200mm axle weighs approximately 400kg), leading to increased unsprung mass and impacting train energy efficiency; short fatigue life: prone to fretting wear under alternating loads, with fatigue cracks frequently appearing during maintenance cycles, posing a failure risk; high energy loss: large rotational inertia, increasing traction energy consumption by 15%-20%. Furthermore, assembling a single carbon fiber axle with steel wheels presents a material mismatch in mechanical properties, with a shear strength attenuation rate as high as 40%, posing significant application risks. Summary of the Invention

[0003] To at least partially solve the technical problems existing in the prior art, the present invention provides a metal carbon fiber composite structure railway axle and a manufacturing method thereof.

[0004] The metal-carbon fiber composite railway axle of the present invention includes a main shaft, a threaded inner tube, an axle head sleeve, and a compression cap. The threaded inner tube is disposed inside the main shaft, the axle head sleeves are symmetrically disposed on both sides of the main shaft, and the compression caps are disposed at both ends of the axle head sleeves and threadedly engage with the threaded inner tube, wherein:

[0005] The main shaft includes a main shaft body and an extension shaft body. The extension shaft bodies are symmetrically arranged at both ends of the main shaft body. The diameter of the extension shaft body is smaller than the diameter of the main shaft body. A transition shoulder is provided between the main shaft body and the extension shaft body.

[0006] A bearing seat is provided on one side of the outer wall of the axle head sleeve. The bearing seat is tapered and used for bearing positioning. A wheel seat is provided on the other side of the outer wall of the axle head sleeve for wheel positioning. A connecting shoulder extends from one end of the axle head sleeve.

[0007] Furthermore, in the aforementioned metal-carbon fiber composite railway axle, the main shaft is formed by winding polyacrylonitrile carbon fiber.

[0008] Furthermore, in the aforementioned metal-carbon fiber composite railway axle, the extended axle body matches the inner diameter of the axle head sleeve, the axle head sleeve and the extended axle body are bonded together with epoxy resin, the transition shoulder and the connecting shoulder are complementary, and the transition shoulder and the connecting shoulder are bonded together with epoxy resin.

[0009] Furthermore, in the aforementioned metal-carbon fiber composite railway axle, the outer wall of the threaded inner tube is provided with a toothed structure, and the two ends of the inner wall of the threaded inner tube are provided with threads.

[0010] Furthermore, in the aforementioned metal-carbon fiber composite railway axle, a stud is provided at one end of the compression cap, the outer diameter of the compression cap matches the outer diameter of the axle head sleeve, the stud matches the thread, and the stud passes through the axle head sleeve and engages with the thread.

[0011] The manufacturing methods for metal-carbon fiber composite railway axles include:

[0012] Spindle fabrication: Select the threaded inner tube according to the design length, and design the diameter of the spindle body, extension spindle body and the transition shoulder in between. Wrap polyacrylonitrile-based carbon fiber on the threaded inner tube, and coat each layer with epoxy resin.

[0013] Axle head sleeve manufacturing: Select axle steel and machine it into an axle head sleeve with a connecting shoulder. Perform precision machining to make the inner and outer walls of the axle head sleeve fit the dimensions. Sandblast the surface to Sa2.5 grade and heat treat the formed axle head sleeve.

[0014] Layered bonding: The transition shoulder and the joint shoulder between the main shaft and the shaft head sleeve are pressed together step by step, and the gaps are filled with epoxy resin slurry;

[0015] Gradient curing: The spindle and the shaft head sleeve after being bonded in layers are placed in a curing device for three-stage temperature curing;

[0016] Tightening cap manufacturing: 40Cr alloy steel is selected, and after heat treatment, it is machined to match the thread inside the threaded inner tube, and then assembled to form a complete railway axle.

[0017] Furthermore, in the aforementioned method for manufacturing railway axles with metal-carbon fiber composite structures, during the main axle fabrication step, the tension during the winding of polyacrylonitrile-based carbon fibers is controlled at 20-50N, and the amount of epoxy resin impregnation between each layer is controlled at 0.3-0.5g / m. 2 The winding speed is controlled at 5-15m / min.

[0018] Furthermore, in the above-mentioned method for manufacturing railway axles with metal-carbon fiber composite structures, in the axle head sleeve manufacturing step, the quenching temperature during tempering is controlled at 850℃, the quenching time is 30min, the tempering temperature is controlled at 550℃, the tempering time is 2h, and the tensile properties are controlled at ReH≥500, Rm: 680-580Mpa, A≥18%.

[0019] Furthermore, in the aforementioned method for manufacturing railway axles with metal-carbon fiber composite structures, in the gradient curing step, the first stage curing temperature is 80℃ and the curing time is 2 hours; the second stage curing temperature is 150℃ and the curing time is 1 hour; and the third stage curing temperature is 200℃ and the curing time is 0.5 hours. After curing, the main shaft has a tensile strength ≥2500 MPa, a modulus ≥200 GPa, and a density ≤1.9 g / cm³. 3 .

[0020] Furthermore, in the above-mentioned method for manufacturing railway axles with metal-carbon fiber composite structures, in the shrink-fit cover manufacturing step, the hardness HRC of the shrink-fit cover after heat treatment is controlled at 28-32.

[0021] The metal-carbon fiber composite railway axle and its manufacturing method of the present invention have the following advantages and beneficial effects:

[0022] This invention improves tensile strength and corrosion resistance while reducing weight through the cooperation between the main shaft and the threaded inner tube. The cooperation between the transition shoulder and the connecting shoulder effectively increases the contact area, avoids axial movement of the main shaft, and effectively improves the structural safety performance. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for further understanding of the embodiments of the present invention and constitute a part of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0024] Fig. 1 This is a schematic cross-sectional view of the metal-carbon fiber composite structure railway axle of the present invention.

[0025] Fig. 2 This is a schematic diagram of the transition shoulder and connecting shoulder of the metal carbon fiber composite structure railway axle of the present invention.

[0026] Fig. 3 The equivalent stress diagram of the axle in the embodiment is shown in the finite element analysis.

[0027] Fig. 4 The equivalent stress diagram of the finite element analysis of the main axis is shown in the embodiment.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1: Main shaft; 11: Main shaft body; 12: Extension shaft body; 13: Transition shoulder;

[0030] 2: Threaded inner tube; 21: Thread;

[0031] 3: Shaft head sleeve; 31: Bearing housing; 32: Wheel seat; 33: Connecting shoulder;

[0032] 4: Tightening cap, 41: Stud. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0034] like Figs. 1-2 As shown, the metal-carbon fiber composite railway axle of the present invention includes a main shaft 1, a threaded inner tube 2, an axle head sleeve 3, and a compression cap 4. The threaded inner tube 2 is disposed inside the main shaft 1, the axle head sleeve 3 is symmetrically disposed on both sides of the main shaft 1, and the compression cap 4 is disposed at both ends of the axle head sleeve 3 and threadedly engages with the threaded inner tube 2.

[0035] The main shaft 1 includes a main shaft body 11 and an extension shaft body 12. The extension shaft body 12 is symmetrically arranged at both ends of the main shaft body 11. The diameter of the extension shaft body 12 is smaller than the diameter of the main shaft body 11. A transition shoulder 13 is provided between the main shaft body 11 and the extension shaft body 12.

[0036] A bearing seat 31 is provided on one side of the outer wall of the axle head sleeve 3. The bearing seat 31 is tapered and used for bearing positioning, which effectively reduces the stress concentration factor. A wheel seat 32 is provided on the other side of the outer wall of the axle head sleeve 3 for wheel positioning. A connecting shoulder 33 extends from one end of the axle head sleeve 3.

[0037] Furthermore, in the metal carbon fiber composite structure railway axle of the present invention, the main shaft 1 is made of polyacrylonitrile carbon fiber winding molding, which effectively reduces the weight while improving tensile strength and corrosion resistance.

[0038] Furthermore, in the metal carbon fiber composite structure railway axle of the present invention, the extended axle body 12 is matched with the inner diameter of the axle head sleeve 3, and the axle head sleeve 3 and the extended axle body 12 are bonded together by epoxy resin adhesive. The transition shoulder 13 and the connecting shoulder 33 are complementary, and the transition shoulder 13 and the connecting shoulder 33 are bonded together by epoxy resin adhesive, which effectively increases the contact area and suppresses axial movement.

[0039] Furthermore, in the metal carbon fiber composite structure railway axle of the present invention, the outer wall of the threaded inner tube 2 is provided with a toothed structure, and the two ends of the inner wall of the threaded inner tube 2 are provided with threads 21, so that the threaded inner tube 2 and the main shaft 1 are mechanically interlocked, thereby enhancing the torsional strength.

[0040] Furthermore, in the metal carbon fiber composite structure railway axle of the present invention, a stud 41 is provided at one end of the compression cover 4. The outer diameter of the compression cover 4 matches the outer diameter of the axle head sleeve 3, and the stud 41 matches the thread 21. The stud 41 passes through the axle head sleeve 3 and engages with the thread 21, thereby effectively strengthening the integrity of the axle head sleeve 3 and the main shaft 1 and avoiding axial displacement of the axle head sleeve 3.

[0041] The manufacturing methods for metal-carbon fiber composite railway axles include:

[0042] Spindle fabrication: Select the threaded inner tube according to the design length, and design the diameter of the spindle body, extension spindle body and the transition shoulder in between. Wrap polyacrylonitrile-based carbon fiber on the threaded inner tube, and coat each layer with epoxy resin.

[0043] Axle head sleeve manufacturing: Select axle steel and machine it into an axle head sleeve with a connecting shoulder. Perform precision machining to make the inner and outer walls of the axle head sleeve fit the dimensions. Sandblast the surface to Sa2.5 grade and heat treat the formed axle head sleeve.

[0044] Layered bonding: The transition shoulder and the joint shoulder between the main shaft and the shaft head sleeve are pressed together step by step, and the gaps are filled with epoxy resin slurry;

[0045] Gradient curing: The spindle and the shaft head sleeve after being bonded in layers are placed in a curing device for three-stage temperature curing;

[0046] Tightening cap manufacturing: 40Cr alloy steel is selected, and after heat treatment, it is machined to match the thread inside the threaded inner tube, and then assembled to form a complete railway axle.

[0047] Furthermore, in the method for manufacturing a railway axle with a metal-carbon fiber composite structure according to the present invention, in the main shaft manufacturing step, the tension during the winding of polyacrylonitrile-based carbon fiber is controlled at 20-50N, and the amount of epoxy resin impregnation between each layer is controlled at 0.3-0.5g / m. 2 The winding speed is controlled at 5-15m / min.

[0048] Furthermore, in the method for manufacturing railway axles with metal carbon fiber composite structure of the present invention, in the axle head sleeve manufacturing step, the quenching temperature during tempering is controlled at 850°C and the quenching time is 30 min, the tempering temperature is controlled at 550°C and the tempering time is 2 h, and the tensile properties are controlled at ReH≥500, Rm: 680-580 MPa, and A≥18%.

[0049] Furthermore, in the method for manufacturing railway axles with metal carbon fiber composite structure of the present invention, in the gradient curing step, the first stage curing temperature is 80°C and the curing time is 2h, the second stage curing temperature is 150°C and the curing time is 1h, and the third stage curing temperature is 200°C and the curing time is 0.5h.

[0050] Furthermore, in the method for manufacturing a railway axle with a metal carbon fiber composite structure according to the present invention, in the step of making the shrink cap, the hardness HRC of the shrink cap after heat treatment is controlled at 28-32.

[0051] Example:

[0052] Spindle fabrication: Select an inner tube with an outer diameter of 100mm, an M65 threaded inner wall, an outer tooth depth of 1.2mm, and a tooth pitch of 4mm, according to the design length. Wrap polyacrylonitrile-based carbon fiber around the inner tube, and coat each layer with epoxy resin. The tension during polyacrylonitrile-based carbon fiber winding is controlled at 20-50N, and the epoxy resin impregnation amount between each layer is controlled at 0.3-0.5g / m. 2 The winding speed is controlled at 5-15m / min, so that the diameter of the extension shaft is 130mm and the diameter of the main shaft is 154mm. The transition shoulder between the extension shaft and the main shaft is divided into 3 steps, each step with a height of 8mm.

[0053] Axle head sleeve fabrication: Axle steel is selected and machined into axle head sleeve with a connecting shoulder. Precision machining is then performed to achieve an inner diameter of 130mm and an outer diameter of 154mm for the connecting shoulder. The connecting shoulder is divided into three steps, each with a height of 8mm. The surface is sandblasted to Sa2.5 grade. The formed axle head sleeve is then tempered. The quenching temperature is controlled at 850℃ for 30 minutes, and the tempering temperature is controlled at 550℃ for 2 hours. Tensile properties are controlled at ReH≥500, Rm: 680-580Mpa, A≥18%.

[0054] Layered bonding: The transition shoulder and the joint shoulder between the main shaft and the shaft head sleeve are pressed together step by step, and the gaps are filled with epoxy resin slurry;

[0055] Gradient curing: The spindle and the shaft head sleeve after layer bonding are placed in the curing equipment for three-stage temperature rise curing. The first stage curing temperature is 80℃ and the curing time is 2h. The second stage curing temperature is 150℃ and the curing time is 1h. The third stage curing temperature is 200℃ and the curing time is 0.5h.

[0056] Manufacturing of the compression cap: 40Cr alloy steel is selected. After heat treatment, the hardness HRC of the compression cap is controlled at 28-32. It is then machined to make the stud have an M65 external thread and assembled to form a complete railway axle.

[0057] In summary, compared with the prior art, the metal carbon fiber composite structure railway axle and manufacturing method of the present invention have the following advantages and beneficial effects: The present invention improves tensile strength and corrosion resistance while reducing self-weight through the cooperation of the main shaft and the threaded inner tube. The cooperation of the transition shoulder and the connecting shoulder effectively increases the contact area, avoids axial movement of the main shaft, and effectively improves the structural safety performance.

[0058] It should be noted that, unless otherwise expressly specified and limited, the term "connection" or its synonyms should be interpreted broadly in this document. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, expressions such as "first" and "second" are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Meanwhile, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. In addition, the terms "front," "rear," "left," "right," "upper," and "lower" in this document refer to the placement states shown in the accompanying drawings.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A metal-carbon fiber composite railway axle, characterized in that, The metal-carbon fiber composite railway axle includes a main shaft, a threaded inner tube, an axle head sleeve, and a compression cap. The threaded inner tube is disposed inside the main shaft, and the axle head sleeves are symmetrically disposed on both sides of the main shaft. The axle head sleeves are made of axle steel. The compression caps are disposed at both ends of the axle head sleeves and engage with the threaded inner tube. The main shaft includes a main shaft body and an extension shaft body. The extension shaft bodies are symmetrically arranged at both ends of the main shaft body. The diameter of the extension shaft body is smaller than the diameter of the main shaft body. A transition shoulder is provided between the main shaft body and the extension shaft body. A bearing seat is provided on one side of the outer wall of the axle head sleeve. The bearing seat is tapered and used for bearing positioning. A wheel seat is provided on the other side of the outer wall of the axle head sleeve for wheel positioning. A connecting shoulder extends from one end of the axle head sleeve. The main shaft is formed by winding polyacrylonitrile carbon fiber onto the threaded inner tube. The extended shaft is matched with the inner diameter of the shaft head sleeve. The shaft head sleeve and the extended shaft are bonded together with epoxy resin. The transition shoulder and the connecting shoulder are complementary. The transition shoulder and the connecting shoulder are bonded together with epoxy resin. The inner wall of the threaded inner tube is provided with threads at both ends; The tightening cap is provided with a stud at one end. The outer diameter of the tightening cap matches the outer diameter of the shaft head sleeve. The stud matches the thread and passes through the shaft head sleeve to engage with the thread.

2. The metal-carbon fiber composite railway axle according to claim 1, characterized in that, The outer wall of the threaded inner tube has a toothed structure.

3. A method for manufacturing a railway axle with a metal-carbon fiber composite structure as described in any one of claims 1 to 2, characterized in that, The manufacturing method of the metal-carbon fiber composite railway axle includes: Spindle fabrication: Select the threaded inner tube according to the design length, and design the diameter of the spindle body, extension spindle body and the transition shoulder in between. Wrap polyacrylonitrile-based carbon fiber on the threaded inner tube, and coat each layer with epoxy resin. Axle head sleeve manufacturing: Select axle steel and machine it into an axle head sleeve with a connecting shoulder. Perform precision machining to make the inner and outer walls of the axle head sleeve fit the dimensions. Sandblast the surface to Sa2.5 grade and heat treat the formed axle head sleeve. Layered bonding: The transition shoulder and the joint shoulder between the main shaft and the shaft head sleeve are pressed together step by step, and the gaps are filled with epoxy resin slurry; Gradient curing: The spindle and the shaft head sleeve after being bonded in layers are placed in a curing device for three-stage temperature curing; Tightening cap manufacturing: 40Cr alloy steel is selected, and after heat treatment, it is machined to match the thread inside the threaded inner tube, and then assembled to form a complete railway axle.

4. The method for manufacturing railway axles with metal-carbon fiber composite structures according to claim 3, characterized in that, During the spindle fabrication process, the tension during polyacrylonitrile-based carbon fiber winding is controlled at 20-50N, and the amount of epoxy resin impregnation between each layer is controlled at 0.3-0.5g / m. 2 The winding speed is controlled at 5-15m / min.

5. The method for manufacturing railway axles with metal-carbon fiber composite structures according to claim 3, characterized in that, In the manufacturing process of the shaft head sleeve, the quenching temperature is controlled at 850℃ and the quenching time is 30min during tempering. The tempering temperature is controlled at 550℃ and the tempering time is 2h. The tensile properties are controlled at ReH≥500, Rm:680-580Mpa, and A≥18%.

6. The method for manufacturing railway axles with metal-carbon fiber composite structures according to claim 3, characterized in that, In the gradient curing process, the first stage curing temperature is 80℃ and the curing time is 2h, the second stage curing temperature is 150℃ and the curing time is 1h, and the third stage curing temperature is 200℃ and the curing time is 0.5h.

7. The method for manufacturing a railway axle with a metal-carbon fiber composite structure according to claim 3, characterized in that, In the manufacturing process of the shrink cap, the hardness HRC of the shrink cap after tempering and heat treatment is controlled at 28-32.

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