Anti-fatigue variable-diameter axle

Abstract

The utility model relates to an anti-fatigue variable-diameter axle, including axle journal section, dustproof plate seat section, wheel seat section, axle body section and middle connecting section along the X axis symmetry distribution, each section is through integrated forging to shape, axle journal section is connected with dustproof plate seat section transition through outer convex arc no.

Description

Technical Field

[0001] This utility model relates to the field of rail vehicle component technology, and in particular to a fatigue-resistant variable diameter axle. Background Technology

[0002] The axle is the core component of a train for load bearing and transmission. It must withstand alternating loads, torques and impact stresses from the wheels for a long time, and its fatigue resistance directly determines the safety of train operation.

[0003] The existing axle technology has the following defects: In the existing technology, the transition parts of each section of the axle are mostly right angles or small arcs, and the axle body is mostly designed with a constant diameter, which cannot adapt to the stress differences of different parts. Moreover, the stress concentration coefficient of key stress areas such as wheel seat and axle journal is high. After 10 million fatigue tests, the axle body is mostly designed with a constant diameter, which cannot adapt to the stress differences of different parts. Some samples have microcracks in the transition parts, which reduces the fatigue life of the overall axle. Utility Model Content

[0004] This utility model addresses the shortcomings of existing technologies by providing a fatigue-resistant variable diameter axle, the specific technical solution of which is as follows:

[0005] A fatigue-resistant variable-diameter axle includes a journal section, a dustproof plate seat section, a wheel seat section, an axle body section, and a central connecting section symmetrically distributed along the X-axis. Each section is integrally forged. The journal section is transitionally connected to the dustproof plate seat section via an outwardly convex arc one, the dustproof plate seat section is transitionally connected to the wheel seat section via an outwardly convex arc two, the wheel seat section is transitionally connected to the axle body section via an outwardly convex arc three, and the two ends of the central connecting section are transitionally connected to the axle body section via an outwardly convex arc four.

[0006] As a further improvement to the above technical solution, the journal section has a diameter of 130-135mm, a length of 200-220mm, and its surface is carburized with a carburized layer depth of 0.8-1.0mm and a surface hardness of HRC58-62 after carburizing.

[0007] As a further improvement to the above technical solution, the outer circumferential surface of the dustproof plate seat section is provided with an annular sealing groove with a width of 20mm and a depth of 3mm, and a sealing ring is embedded in the annular sealing groove; the diameter of the dustproof plate seat section is 8-10mm larger than that of the journal section, and the length is 150-160mm; the radius of the outer convex arc is 50-60mm, its starting point is tangent to the cylindrical surface at the end of the journal section, and its ending point is tangent to the cylindrical surface at the front end of the dustproof plate seat section.

[0008] As a further improvement to the above technical solution, the diameter of the wheel seat section is 180-190mm, and the interference with the wheel hub is 0.05-0.08mm; the three convex arcs near the dustproof plate seat section and the axle body section each have a shallow circumferential groove with a width of 10mm and a depth of 1mm, and a nickel-titanium alloy elastic ring is built into them.

[0009] As a further improvement to the above technical solution, the axle section has a stepped diameter design, with a diameter of 160-170mm at the end near the wheel seat section, gradually decreasing to 150-155mm towards the middle connecting section, and a length of 800-850mm; six carbon fiber reinforcing ribs are embedded axially inside, which are forged and composite formed with EA1N steel, and one end of the carbon fiber reinforcing ribs extends from the wheel seat section to the middle connecting section.

[0010] As a further improvement to the above technical solution, the diameter of the middle connecting section is 150-155mm and the length is 200-220mm, and the inside is provided with a through hole with a diameter of 30-35mm; the inside of the shaft section has a plug near the middle connecting section, and the plug is inserted into the through hole and fixed by interference fit.

[0011] The beneficial effects of this utility model are:

[0012] 1. The stress concentration factor at the connection points of each section is reduced to 1.2-1.3 by the outward convex arc transition, and the torsional stiffness of the shaft section is effectively improved by the carbon fiber reinforcement; the nickel-titanium alloy elastic ring can be stretched by 0.5-1mm under impact load, absorbing impact energy and reducing stress transmission.

[0013] 2. Precise interference fit of the wheel seat section reduces fretting wear; IP65 dustproof and waterproof rating is achieved through annular sealing groove and fluororubber sealing ring to avoid the effects of rust; stepped variable diameter design adapts to the stress differences of different parts, effectively improving load-bearing capacity. Attached Figure Description

[0014] Fig. 1 This is a three-dimensional structural diagram of the entire utility model;

[0015] Fig. 2 This is a schematic diagram of the overall internal structure of this utility model.

[0016] Reference numerals: 1. Journal section; 100. Tapered structure; 2. Outer convex arc one; 3. Dustproof plate seat section; 30. Annular sealing groove; 31. Sealing ring; 4. Outer convex arc two; 5. Wheel seat section; 6. Outer convex arc three; 60. Circumferential shallow groove; 61. Nickel-titanium alloy elastic ring; 7. Shaft body section; 71. Insert post; 8. Outer convex arc four; 9. Middle connecting section; 90. Through hole; 10. Carbon fiber reinforcing rib. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0018] Example

[0019] A fatigue-resistant variable diameter axle, reference Figs. 1-2 It is made of modified EA1N steel (containing 1.0% Cr, 0.3% C, and 0.2% Si) through integrated forging, and the whole is symmetrically distributed along the X-axis.

[0020] Specifically, journal section 1 has a diameter of 132mm and a length of 210mm, and its end can be set with a 1:10 taper structure 100 (to facilitate mating with the inner ring of the bearing); its surface is carburized at 920℃ with a carburized layer depth of 0.9mm, and the surface hardness after quenching is HRC60 (core hardness HRC30-35), ensuring a balance between the wear resistance of the mating surface with the bearing and the toughness of the core.

[0021] Specifically, the dustproof plate seat section 3 has a diameter of 140mm (8mm larger than the journal section) and a length of 155mm; an annular sealing groove 30 (20mm wide and 3mm deep) is machined on the outer circumference, and a fluororubber sealing ring 31 (circular cross-section, 3mm in diameter) is embedded inside to achieve a sealing fit with the dustproof plate, achieving a waterproof and dustproof rating of IP65; it transitions to the journal section 1 through an outwardly convex arc 2 (radius 55mm), with the starting point of the arc tangent to the end of the journal section 1 and the ending point tangent to the front end of the dustproof plate seat section 3, eliminating stress concentration from the right-angle transition.

[0022] Specifically, the diameter of wheel seat section 5 is 185mm, the length is 200mm, and the interference with the wheel hub is 0.06mm (to ensure no relative slippage when transmitting torque);

[0023] The transition between the outer convex arc 2 4 (radius 45mm) and the dustproof plate seat section 3 is achieved through the outer convex arc 3 6 (radius 65mm) with shallow circumferential grooves 60 (10mm wide and 1mm deep) on both sides, each containing a nickel-titanium alloy elastic ring 61 (1mm thick). At room temperature, the ring is in a contracted state, but it can stretch to 1.2mm when subjected to impact, absorbing impact energy to protect the transition area.

[0024] The axle section 7 adopts a stepped diameter design, with a diameter of 165mm at the end near the wheel seat section 5, gradually decreasing to 152mm towards the central connecting section 9, and a length of 820mm. Six carbon fiber reinforcing ribs 10 (5mm in diameter, spaced at 60°) are embedded axially inside, extending from the wheel seat section 5 to the central connecting section 9. Combined with forged steel, the torsional stiffness reaches 3.2 × 10⁻⁶. 5 N·m 2(15% improvement over traditional structures).

[0025] The middle connecting section 9 has a diameter of 152mm and a length of 210mm, with an axial through hole 90 (diameter of 32mm) inside; the shaft section 7 has an integrally formed insert 71 (diameter of 31mm and length of 50mm) at one end near the middle, and the insert 71 and the through hole 90 are interference-fitted (interference amount of 0.02mm) to enhance the integrity of the shaft and the middle connecting section; the shaft section 7 is transitioned to the shaft section 7 through the outward convex arc 8 (radius of 52mm) to further disperse the stress in the middle.

[0026] Specifically, in the heat treatment process of this application, the whole body is normalized at 860℃ for 2 hours and then air-cooled. The metallographic structure is fine pearlite with a small amount of ferrite, the yield strength is 360MPa, and the impact toughness is 45J / cm. 2 (-40℃ low temperature impact) meets the usage requirements of 25t axle load heavy-duty trains.

[0027] Working principle

[0028] When the axle is working, the journal section 1 bears the radial load transmitted by the bearing, and the tapered structure 100 ensures a tight fit with the bearing, while the carburized layer resists wear. The sealing ring 31 of the dustproof plate seat section 3 prevents dust and moisture from entering and protects the mating surface between the journal and the bearing. The wheel seat section 5 drives the wheel to rotate through an interference fit, and the nickel-titanium alloy elastic ring 61 is stretched and deformed under the impact load of the wheel to absorb energy and reduce the stress of the convex arc 3 6. The stepped diameter design of the axle body section 7 adapts to the bending moment distribution at different positions, and the carbon fiber reinforcing rib 10 improves the torsional resistance and reduces bending deformation. The interference fit between the insert 71 and the through hole 90 of the middle connecting section 9 enhances the overall rigidity, and the large radius transition of the convex arcs 1 2, 2 4, 3 6, and 4 8 keeps the stress concentration factor within 1.2. Combined with the high toughness of the improved material, the fatigue life of the axle is significantly improved.

[0029] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A fatigue resistant variable diameter axle, comprising: It includes a journal section (1), a dustproof plate seat section (3), a wheel seat section (5), a shaft body section (7), and a central connecting section (9) symmetrically distributed along the X-axis. Each section is formed by integral forging. The journal section (1) is connected to the dustproof plate seat section (3) through an outward convex arc one (2). The dustproof plate seat section (3) is connected to the wheel seat section (5) through an outward convex arc two (4). The wheel seat section (5) is connected to the shaft body section (7) through an outward convex arc three (6). The two ends of the central connecting section (9) are connected to the shaft body section (7) through an outward convex arc four (8).

2. The fatigue-resistant variable-diameter axle of claim 1, wherein: The journal section (1) has a diameter of 130-135mm and a length of 200-220mm, and has a tapered structure (100) at the end.

3. The fatigue-resistant variable diameter axle of claim 1, wherein: The outer circumferential surface of the dustproof plate seat section (3) is provided with an annular sealing groove (30) with a width of 20mm and a depth of 3mm, and a sealing ring (31) is embedded in the annular sealing groove (30); the diameter of the dustproof plate seat section (3) is 8-10mm larger than that of the journal section (1), and the length is 150-160mm; the starting point of the outward convex arc (2) is tangent to the end cylindrical surface of the journal section (1), and the ending point is tangent to the front cylindrical surface of the dustproof plate seat section (3).

4. The fatigue-resistant variable diameter axle of claim 1, wherein: The diameter of the wheel seat section (5) is 180-190mm, and the interference with the wheel hub is 0.05-0.08mm; the outer convex arc three (6) is close to the two ends of the dustproof plate seat section (3) and the axle body section (7), and each has a circumferential shallow groove (60) with a width of 10mm and a depth of 1mm, and the circumferential shallow groove (60) is equipped with a nickel-titanium alloy elastic ring (61).

5. The fatigue-resistant variable diameter axle of claim 1, wherein: The axle section (7) has a stepped diameter design, with a diameter of 160-170mm at the end near the wheel seat section (5) and gradually decreasing to 150-155mm towards the middle connecting section (9), and a length of 800-850mm. Multiple carbon fiber reinforcing ribs (10) are embedded axially inside the axle section (7), with one end of the carbon fiber reinforcing rib extending from the wheel seat section (5) to the middle connecting section (9).

6. The fatigue-resistant variable diameter axle of claim 1, wherein: The middle connecting section (9) has a diameter of 150-155mm and a length of 200-220mm, and has a through hole (90) with a diameter of 30-35mm inside; the shaft section (7) has a plug (71) at one end near the middle connecting section (9), and the plug (71) is inserted into the through hole (90) and fixed by interference fit.

7. The fatigue-resistant variable-diameter axle of claim 3, wherein: The radius of the first convex arc (2) is 50-60mm, the radius of the second convex arc (4) is 40-50mm, the radius of the third convex arc (6) is 60-70mm, and the radius of the fourth convex arc (8) is 50-55mm.

8. The fatigue-resistant variable diameter axle of claim 3, wherein: The sealing ring (31) is made of fluororubber.

9. The fatigue-resistant variable-diameter axle of claim 5, wherein: The carbon fiber reinforcing ribs (10) are provided in a total of 6, and are evenly distributed at 60° intervals along the circumference of the shaft section (7).

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