Axle tube of heavy-load vehicle

Abstract

An axle tube of a heavy-load vehicle belongs to the technical field of vehicle axles and comprises an axle tube, two groups of square sleeves and axle heads, and the two groups of square sleeves are fixedly assembled at two ends of an inner cavity of the axle tube respectively; one end of each group of shaft heads is in interference fit with the inner cavity of the corresponding square sleeve, and the other end of each group of shaft heads extends out of the shaft tube; the circumferential butt joint parts of the axle head and the axle tube are fixedly connected into a whole through ring welding, and the square sleeve increases the matching length of the axle head and the axle tube, so that the integral structure of the axle tube is formed. The square sleeve is additionally arranged in the axle tube, the square sleeve and the axle head form an interference fit structure, and the circumferential butt joint parts of the axle head and the axle tube are fixedly connected into a whole through ring welding, so that the integral axle tube structure is jointly formed; according to the structure, the effective matching length of the shaft tube and the shaft head is prolonged, the assembly binding face and the stress transmission area of the shaft tube and the shaft head are increased, local high stress is effectively dispersed, and the structural rigidity and fatigue resistance of a stress concentration area are effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of vehicle axle technology, specifically relating to an axle tube for a heavy-duty vehicle. Background Technology

[0002] Currently, trailer axle tubes are mainly divided into two types: one-piece axle tubes and welded axle tubes. One-piece axle tubes are made using a single molding process, which is simple to process, but the structural strength is limited and the load-bearing capacity is relatively low, making it difficult to meet the requirements of heavy-duty working conditions; therefore, the axle tubes of 20-25 ton heavy-duty vehicles mostly adopt welded structures.

[0003] However, as Figure 17 As shown, the welded axle tubes used in existing heavy-duty vehicles have a short mating length between the axle head and the tube, resulting in insufficient assembly contact area. Furthermore, the welding area between the axle tube and the axle head is located at a point of concentrated axle stress. Under heavy loads, impacts, and alternating loads, these factors can easily lead to excessive stress at the welded joint, decreased overall fatigue resistance, and ultimately, a risk of fracture failure at the connection between the axle tube and the axle head. Summary of the Invention

[0004] To address the problems of short mating lengths and insufficient contact area between the axle head and tube in existing welded axle tubes used in heavy-duty vehicles, this invention provides an axle tube for heavy-duty vehicles. A square sleeve is added inside the axle tube, forming an interference fit with the axle head. The circumferential joint between the axle head and the axle tube is then circumferentially welded together to form an integral axle tube structure. This structure extends the effective mating length between the axle tube and the axle head, increases the contact area and stress transfer area, effectively disperses localized high stress, and significantly improves the structural stiffness and fatigue strength of stress concentration areas, enabling better resistance to heavy loads, impacts, and alternating loads. The specific technical solution is as follows: A heavy-duty vehicle axle tube includes an axle tube, a square sleeve, and an axle head. Two sets of square sleeves are provided, and the two sets of square sleeves are respectively fixedly assembled to both ends of the inner cavity of the axle tube. Two sets of axle heads are provided, and one end of each axle head is interference-fitted with the inner cavity of the corresponding square sleeve, while the other end extends to the outside of the axle tube. The axle head and the axle tube are circumferentially welded together to form a single unit, and the square sleeve increases the mating length between the axle head and the axle tube, thereby jointly forming the overall structure of the axle tube.

[0005] In the above technical solution, four welding holes are provided through the front and rear side walls of the shaft tube, and two welding holes that are opposite each other are arranged in a corresponding group; the two groups of welding holes that are opposite each other are connected by plug welding, thereby forming a corresponding pin structure at the mating position of the shaft tube and the shaft head.

[0006] In the above technical solution, the overlapping part of the sleeve between the shaft tube and the shaft head is correspondingly set at the installation position of the brake base plate of the heavy-duty vehicle, and the brake base plate is welded to the front and rear sides and the top of the shaft tube in sections.

[0007] In the above technical solution, the shaft tube includes a tube body, a first bevel, and a second bevel. The tube body is a hollow, elongated tubular structure, and the four corners of the inner wall and the four corners of the outer wall of the tube body are rounded. The first bevel is inclinedly disposed at the end of the tube body. The second bevel is disposed on the inner wall of the tube body and smoothly transitions with the first bevel.

[0008] In the above technical solution, the square sleeve includes a sleeve body, a circular hole, and a third bevel. The sleeve body is a hollow structure and is fixed in the inner cavity of the shaft tube. The circular hole is opened through the sleeve body and together with the sleeve body, forms an overall structure of outer square and inner circle. The third bevel is inclined along the outer side wall of the sleeve body and is located on the side of the sleeve body near the shaft head.

[0009] In the above technical solution, the outer diameter of the sleeve and the inner diameter of the tube are matched in shape and size.

[0010] In the above technical solution, the shaft head includes a main shaft section, a square piece, and an extension shaft section, and the main shaft section, the square piece, and the extension shaft section are integrally formed; the extension shaft section is disposed at the end of the main shaft section, and the square piece is disposed on the main shaft section; the extension shaft section is interference-fitted with the circular hole, and the square piece and the circumferentially mating part of the shaft tube are circumferentially welded together.

[0011] In the above technical solution, the shaft head further includes a threaded portion, a first recessed portion, and a second recessed portion. The threaded portion is disposed at the end of the main shaft section and is disposed opposite to the extension shaft section. The second recessed portion is disposed inside the extension shaft section, and the first recessed portion is disposed at the end of the main shaft section away from the extension shaft section.

[0012] In the above technical solution, the shaft head is a high-strength solid steel forging that has undergone quenching and tempering treatment.

[0013] In the above technical solution, the two sets of square sleeves and the two sets of shaft heads are arranged symmetrically from left to right with the central axis of the shaft tube as the reference.

[0014] The axle tube of the heavy-duty vehicle of the present invention has the following advantages compared with the prior art: I. Addressing the shortcomings of existing welded axles for heavy-duty vehicles, such as short axle head and axle tube mating lengths, and welded joints located in stress-concentrated areas, leading to excessive stress and insufficient fatigue resistance under heavy and alternating loads, resulting in a risk of joint fracture failure, this invention adds a square sleeve inside the axle tube. This square sleeve forms an interference fit with the axle head, and the circumferential mating parts of the axle head and axle tube are circumferentially welded together to form an integral axle tube structure. This structure extends the effective mating length between the axle tube and axle head, increases the assembly contact surface and stress transfer area, effectively disperses localized high stress, and significantly improves the structural stiffness and fatigue strength of stress-concentrated areas. It can better withstand heavy loads, impacts, and alternating loads, reducing the risk of joint cracking and fracture failure, effectively improving the overall load-bearing capacity and operational reliability of the axle tube, and extending the service life of the axle. II. Traditionally, the connection between the axle tube and the axle head is mostly achieved by four-point circumferential plug welding. This results in a large number of weld points, which can easily lead to multiple stress concentration points in the welding area, thus creating potential weaknesses in the load-bearing capacity. To address this deficiency, this invention only sets two sets of weld holes on the front and rear side walls of the axle tube, i.e., adopting a double-hole plug welding structure. This eliminates the need for weld point arrangement in the vertical direction. When the axle is bent, the central area in the height direction of the cross-section is a neutral layer with a low stress level, which does not weaken the overall load-bearing capacity. This arrangement conforms to the stress distribution law of the axle cross-section. In the neutral layer area, it does not affect the overall load-bearing capacity. At the same time, the corresponding plug welding at the front and rear ends forms a symmetrical pin structure at the mating position of the axle tube and the axle head. This not only reduces the number of weld points and the potential for stress concentration, but also further enhances the shear resistance and circumferential restraint between the axle tube and the axle head, making the connection between the two more tight and reliable, and effectively improving the structural stability and impact resistance of the connection. Third, existing axle heads mostly use cast steel parts, which have limited rigidity and strength. In this invention, the axle head is made of high-strength solid steel forgings that have undergone quenching and tempering. The quenching and tempering process can improve the comprehensive mechanical properties of the material, giving the axle head both high strength and good toughness, and reducing the risk of brittle fracture. The solid forging structure further improves the local compressive and shear resistance. After assembling and welding the axle head and axle tube into a whole, the overall strength, rigidity and fatigue resistance of the axle can be improved, effectively increasing the rated load capacity of the axle tube, making it more suitable for the load, impact and other operating conditions of heavy-duty vehicles, and ensuring the reliability of axle operation. IV. Conventional welding of existing brake base plates and axle tubes mostly adopts continuous annular welds. The welding stress is mainly longitudinal tensile stress and transverse shrinkage tensile stress. The closed annular structure is prone to forming significant circumferential clamping stress, which can easily lead to problems such as deformation, warping, and even weld cracking of the brake base plate. In order to address the above problems, in this invention, the brake base plate and axle tube adopt a segmented welding structure with segmented welding on the front and rear sides and top, and no welding at the bottom, instead of a closed welding structure. This effectively breaks the closed annular weld and avoids the residual stress of circumferential clamping welding caused by weld cooling and shrinkage, thereby reducing welding deformation and internal stress concentration, and reducing the risk of brake base plate warping and cracking. At the same time, the overlapping part of the sleeve between the axle tube and the axle head corresponds to the installation area of ​​the brake base plate, so that the force during braking is directly applied to the reinforced section with added square sleeve, further improving the structural stability and bending and torsional strength of the axle tube under braking impact, ensuring that the overall axle is subjected to more uniform force and operates more reliably during heavy-load braking. V. The square sleeve in this structure adopts an outer circle and inner square design. Its outer circular outline can fit tightly with the square inner wall of the shaft tube, and the inner square hole matches the shape of the mating section of the axle head. This square mating surface can effectively restrict the circumferential relative rotation between the square sleeve and the shaft tube, and between the square sleeve and the axle head, to achieve reliable circumferential positioning. After the axle head is inserted into the square sleeve to form an interference fit and is welded to the shaft tube, the square force transmission surface can directly bear and transmit torque and rotational shear force, effectively improving the overall torsional resistance and preventing the axle head from failing due to relative rotation under heavy braking and driving impact. This structure makes the shaft tube, square sleeve and axle head form a rigid integrated composite force-bearing structure, further improving the overall torsional stiffness, transmission stability and operational reliability of the axle. In summary, this invention, through multiple structural improvements such as adding a square sleeve inside the axle tube to extend the fitting length of the axle head, optimizing the plug welding point and utilizing the stress law of the neutral layer of the cross section, using a tempered solid steel forged axle head, employing non-closed segmented welding on the brake base plate to eliminate circumferential clamping stress, and designing the square sleeve as an outer circle with an inner square structure to achieve reliable circumferential limiting, increases the contact and force transmission area between the axle tube and the axle head, effectively disperses stress concentration, and improves the overall strength, stiffness, fatigue resistance, and torsional resistance of the axle; at the same time, it reduces welding residual stress and the risk of deformation and cracking, enhances the shear resistance, impact resistance, and structural stability of the connection parts, enabling the axle to better adapt to heavy load, impact, and alternating load conditions, improve the overall vehicle operating reliability and load-bearing capacity, and effectively extend the service life of the axle. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the tube body in Embodiment 1 of the present invention; Figure 2 This is a front view of the tube body in Embodiment 1 of the present invention; Figure 3 This is a partial cross-sectional structural diagram of the tube body in Embodiment 1 of the present invention; Figure 4 for Figure 3 Enlarged view of point A; Figure 5 This is a schematic diagram of the structure of the body in Embodiment 1 of the present invention; Figure 6 for Figure 5 Enlarged view of point B; Figure 7 This is a schematic diagram of the third bevel structure in Embodiment 1 of the present invention; Figure 8 This is a schematic diagram of the circular hole in Embodiment 1 of the present invention; Figure 9 This is a schematic diagram of the extended shaft segment inserted into the square sleeve in Embodiment 1 of the present invention; Figure 10 This is a schematic diagram of the weld hole structure in Embodiment 1 of the present invention; Figure 11 for Figure 10 Enlarged view of point C; Figure 12 This is a front view of the weld hole in Embodiment 1 of the present invention; Figure 13 This is a schematic diagram of the structure of the square piece in Embodiment 1 of the present invention; Figure 14 This is a schematic diagram of the structure of the first recessed portion in Embodiment 1 of the present invention; Figure 15 This is a schematic diagram of the structure of the second recess in Embodiment 1 of the present invention; Figure 16 This is a schematic diagram of the structure of the braking base plate in Embodiment 2 of the present invention; Figure 17 This is a partial cross-sectional structural diagram of the connection between the shaft tube and the shaft head in the prior art; Figures 1 to 16 In the middle, 1. Shaft tube, 101. Tube body, 102. First bevel, 103. Second bevel, 2. Square sleeve, 201. Sleeve body, 202. Round hole, 203. Third bevel, 3. Shaft head, 301. Main shaft section, 302. Square piece, 303. Extension shaft section, 304. Threaded part, 305. First recessed part, 306. Second recessed part, 4. Weld hole, 5. Brake base plate. Detailed Implementation

[0016] The following are specific implementation cases and appendices. Figures 1 to 14 The present invention will be further described, but the present invention is not limited to these embodiments.

[0017] Example 1 Main references Figures 1 to 13As shown, an axle tube for a heavy-duty vehicle includes an axle tube 1, a square sleeve 2, and an axle head 3. Two sets of square sleeves 2 are provided, and each set is fixedly assembled to both ends of the inner cavity of the axle tube 1, thereby increasing the length of the connection between both ends of the axle tube 1. Two sets of axle heads 3 are provided, with one end of each axle head 3 having an interference fit with the inner cavity of the corresponding square sleeve 2, and the other end extending to the outside of the axle tube 1. Through the interference fit between the axle head 3 and the square sleeve 2, a stable connection can be achieved between the two without relative movement or rotation. The circumferential mating portion of the axle head 3 and the axle tube 1 is circumferentially welded together, and the square sleeve 2 increases the mating length between the axle head 3 and the axle tube 1, thus forming the overall structure of the axle tube. When the axle head 3 is interference-fitted with the square sleeve 2 and welded to the axle tube 1 to form a whole, the torsional resistance of the above components can be improved, preventing the axle head 3 from rotating circumferentially under heavy braking and driving impact. This allows the axle tube 1, square sleeve 2, and axle head 3 to form a stable rigid whole, significantly improving the overall torsional stiffness of the axle, strengthening the structural integrity and force transmission continuity between components, and thus improving the operational stability of the axle under long-term heavy loads and alternating loads. Specifically, the two sets of square sleeves 2 and the two sets of axle heads 3 are arranged symmetrically with respect to the central axis of the axle tube 1. This symmetrical structural design ensures that the axle heads 3 at both ends are coaxially and symmetrically assembled with respect to the axle tube 1, effectively ensuring the symmetrical distribution and balanced transmission of the overall force on the axle tube under load, braking, and alternating loads. This avoids local overload, uneven wear, and additional bending moments caused by assembly misalignment or uneven force, improving the overall operational stability and structural reliability of the axle.

[0018] This invention adds a square sleeve 2 to the inner cavity of the shaft tube 1, forming an interference fit with the shaft head 3. The circumferential joint between the shaft head 3 and the shaft tube 1 is then fixed by circumferential welding, making the three components an integral axle tube structure. By adding the square sleeve 2, the effective fit length between the shaft tube 1 and the shaft head 3 is effectively extended, increasing the contact surface and load transfer area. This effectively disperses and releases the high stress originally concentrated in the weld area, significantly improving the structural stiffness and fatigue resistance of this critical load-bearing component. Through actual testing, it has been verified that compared with the existing conventional welded axle tubes, the overall load-bearing capacity of this structure is increased by 20%-30%, the fatigue strength of the stress concentration area is increased by more than 35%, and the maximum stress at the weld is reduced by about 40%. It can more stably withstand the continuous action of heavy loads, impacts and alternating loads, and reduce the possibility of cracking or even fracture failure at the connection between the axle tube and the axle head. This improves the overall load-bearing performance and long-term working reliability of the axle tube. Compared with the conventional axle tube and axle head connection structure, the service life of the axle is extended by 25%-30%.

[0019] Traditional shaft tubes and shaft ends are often connected using circumferential four-point plug welding. This results in a large number of weld points, which easily create multiple stress concentration points in the welding area, potentially leading to weak points under stress. To address this deficiency, please refer to... Figure 1 , Figures 10 to 12 As shown, the present invention has four welding holes 4 penetrating through the front and rear side walls of the shaft tube 1, with two welding holes 4 facing each other in a corresponding group. (See main references) Figures 1 to 3 As shown, the welding state of weld holes 4 is illustrated. This invention provides two sets of weld holes 4 on the front and rear sidewalls of the axle tube 1, employing a front and rear double-hole plug welding structure, omitting weld points in the vertical direction. When the axle is bent, the central region of its cross-section in the height direction is a neutral layer with extremely low stress levels. Eliminating weld points in this region does not reduce the overall load-bearing capacity. This arrangement conforms to the natural stress characteristics of the axle cross-section, reducing stress concentration sources by reducing the number of weld points without sacrificing load-bearing performance. Furthermore, the two sets of weld holes 4 are connected by plug welding, forming a corresponding pin structure at the mating position of the axle tube 1 and the axle head 3. This invention utilizes symmetrical plug welding to form a symmetrical pin structure at the mating position of the axle tube 1 and the axle head 3, further enhancing the shear resistance and circumferential restraint effect between the axle tube and the axle head, making the connection tighter and more integral, significantly improving the structural stability and impact resistance of the connection.

[0020] Main references Figure 5 and Figure 6 As shown, the shaft tube 1 includes a tube body 101, a first bevel 102, and a second bevel 103. The tube body 101 is a hollow, elongated tubular structure, and the four corners of both the inner and outer walls of the tube body 101 are rounded to ensure that there is no interference with the rounded corners of the shaft head. The first bevel 102 is inclined at the end of the tube body 101; the second bevel 103 is located on the inner wall of the tube body 101 and smoothly transitions to the first bevel 102. The second bevel 103 can cooperate with the arc surface on the shaft head 3, promoting a more stable connection between the shaft head 3 and the shaft tube 1. Furthermore, the first bevel 102 and the second bevel 103 allow the welding wire or molten pool to penetrate deep into the root of the joint between the shaft head 3 and the shaft tube 1, achieving full penetration welding, avoiding defects such as incomplete penetration and weak welds, and improving the weld strength.

[0021] Main references Figures 5 to 9As shown, the square sleeve 2 includes a sleeve body 201, a circular hole 202, and a third bevel 203. The sleeve body 201 is a hollow structure and is fixed to the inner cavity of the shaft tube 1. The circular hole 202 is opened through the sleeve body 201 and together with the sleeve body 201, forms an overall structure with an outer square and an inner circle. The third bevel 203 is inclined circumferentially along the outer wall of the sleeve body 201 and is located on the side of the sleeve body 201 near the shaft head 3. The third bevel 203 is used to achieve welding between the sleeve body 201 and the shaft tube 1. In this structure, the square sleeve 2 adopts an irregular structure with an outer circle and an inner square. Its outer cylindrical surface can fit tightly with the square inner wall of the shaft tube 1, and the inner square hole is consistent with the shape of the mating section of the shaft head 3. Through the limiting effect of the square mating surface, the relative circumferential rotation between the square sleeve 2 and the shaft tube 1, and between the square sleeve 2 and the shaft head 3 can be effectively prevented, thus achieving stable circumferential positioning. Specifically, the outer diameter of the sleeve 201 matches the inner diameter of the tube 101 in shape and size, ensuring that the two fit tightly and are accurately positioned after assembly. This effectively avoids loosening, wobble and abnormal noise caused by assembly gaps, forming a rigid and stable connection between the two, improving the coaxiality and stress uniformity of the overall structure, thereby enhancing the torsional and impact resistance of the connection and ensuring the reliability of the connection under long-term heavy load conditions.

[0022] Main references Figure 1 , Figures 3 to 5 , Figure 9 As shown, the shaft head 3 includes a main shaft section 301, a square piece 302, and an extension shaft section 303, and the main shaft section 301, the square piece 302, and the extension shaft section 303 are integrally formed. The extension shaft section 303 is disposed at the end of the main shaft section 301 and is used to extend the overall length of the main shaft section 301 within the shaft tube 1. The square piece 302 is disposed on the main shaft section 301, which can limit the insertion length of the main shaft section 301 relative to the shaft tube 1, and also provide a larger welding position for the subsequent circumferential welding of the square piece 302 and the shaft tube 1. The extension shaft section 303 is interference-fitted with the circular hole 202. (See main reference...) Figure 1 and Figure 2 As shown, the square piece 302 and the shaft tube 1 are circumferentially welded together. Additionally, see the main reference... Figure 14 and Figure 15As shown, the axle head 3 also includes a threaded portion 304, a first recessed portion 305, and a second recessed portion 306. The threaded portion 304 is located at the end of the main shaft section 301 and is positioned opposite to the extension shaft section 303. The second recessed portion 306 is located inside the extension shaft section 303, and the first recessed portion 305 is located at the end of the main shaft section 301 opposite to the extension shaft section 303. The first recessed portion 305 and the second recessed portion 306 are shallow holes created during forging; both are blind holes, which reduces the overall weight of the axle head 3 without affecting its solid structure or stress distribution. The threaded portion 304 can be used with commonly used nuts, anti-reverse washers, and other fasteners to axially press and fix components such as wheel hubs and tapered roller bearings. In other words, the threaded portion 304 is used to achieve the connection and assembly between the axle tube and the vehicle as a whole.

[0023] Conventional axle heads are mostly made of cast steel, which has low overall density and relatively limited strength and stiffness, making them prone to deformation or fracture under heavy loads. In this invention, the axle head 3 is a high-strength solid steel forging that has undergone quenching and tempering. Specifically, the axle head 3 is made of high-quality alloy structural steel, forged into a solid forging, and then subjected to quenching and high-temperature tempering heat treatment. Quenching provides a high-hardness and high-strength matrix, followed by high-temperature tempering to eliminate internal stress and balance the microstructure, giving the material excellent strength, toughness, and impact resistance, effectively reducing the tendency for brittle fracture. The solid forging structure further improves local compressive, shear, and torsional resistance. After assembling and welding the axle head 3 to the axle tube 1, the overall structural strength, stiffness, and fatigue life of the axle are effectively improved, as is the rated load-bearing capacity of the axle tube. This allows it to withstand harsh conditions of heavy loads, large impacts, and alternating loads for extended periods, significantly improving the axle's operational stability and service life.

[0024] This invention improves the fit and force transmission area between the axle tube and the axle head by adding a square sleeve 2 inside the axle tube 1 to extend the fit length of the axle head 3, optimizing the plug welding point and utilizing the stress law of the neutral layer of the cross section, using a tempered solid steel forged axle head, and designing the square sleeve 2 as an outer circle with an inner square structure to achieve reliable circumferential limiting. This increases the fit and force transmission area between the axle tube and the axle head, effectively disperses stress concentration, and improves the overall strength, stiffness, fatigue resistance, and torsional resistance of the axle. At the same time, it reduces welding residual stress and the risk of deformation and cracking, enhances the shear resistance, impact resistance, and structural stability of the connection parts, and enables the axle to better adapt to heavy load, impact, and alternating load conditions, improves the reliability and load-bearing capacity of the vehicle, and effectively extends the service life of the axle.

[0025] Example 2 Traditional brake backplates and axle tubes are typically welded using a continuous circumferential weld. During welding, longitudinal tensile stress and transverse contraction stress are generated. After cooling, the closed circumferential weld is prone to forming strong circumferential residual stress, leading to welding deformation, warping, and even weld cracking of the brake backplate. To address these defects, please refer to [reference needed]. Figure 14As shown, in this invention, the overlapping part of the sleeve between the axle tube 1 and the axle head 3 is correspondingly located at the installation position of the heavy-duty vehicle brake base plate 5. The brake base plate 5 and the axle tube 1 are welded in sections on the front and rear sides and the top, while the bottom is not welded. This structure breaks the traditional closed circumferential seam structure, thereby avoiding the circumferential clamping stress generated by the cooling and shrinkage of the weld, effectively reducing the residual welding stress and deformation, and reducing the possibility of warping and cracking of the brake base plate. At the same time, the overlapping area of ​​the sleeve between the axle tube 1 and the axle head 3 corresponds exactly to the installation position of the brake base plate 5, so that the braking load is directly applied to the reinforcing section with the added square sleeve 2, further improving the bending and torsional resistance and structural stability of the axle tube under braking impact, ensuring that the overall stress of the axle is more uniform under heavy-duty braking conditions, and the operation is safer and more reliable.

[0026] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0027] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0028] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.

[0029] Furthermore, the terms "set up," "connect," and "fix" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0030] Unless otherwise stated, the term "multiple" means two or more.

[0031] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0032] The term "and / or" describes the relationship between objects, indicating that there can be three relationships. For example, A and / or B means: A or B, or A and B.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An axle tube for a heavy-duty vehicle, characterized in that: It includes a shaft tube (1), a square sleeve (2) and a shaft head (3). The square sleeve (2) is provided in two sets, and the two sets of square sleeves (2) are respectively fixedly assembled at both ends of the inner cavity of the shaft tube (1). The shaft head (3) is provided in two sets, and one end of each set of shaft heads (3) is interference-fitted with the inner cavity of the corresponding square sleeve (2), and the other end extends to the outside of the shaft tube (1). The circumferential mating parts of the axle head (3) and the axle tube (1) are fixed together by circumferential welding. The square sleeve (2) increases the mating length between the axle head (3) and the axle tube (1), thereby forming an integral structure of the axle tube.

2. The axle tube of the heavy-duty vehicle according to claim 1, characterized in that: The front and rear side walls of the shaft tube (1) are provided with four welding holes (4), and the two welding holes (4) that are opposite to each other are arranged in a corresponding group. The two groups of welding holes (4) that are opposite to each other are connected by plug welding, thereby forming a corresponding pin structure at the mating position of the shaft tube (1) and the shaft head (3).

3. The axle tube of the heavy-duty vehicle according to claim 1, characterized in that: The overlapping part of the sleeve tube (1) and the shaft head (3) is correspondingly set at the installation position of the heavy-duty vehicle brake base plate (5). The brake base plate (5) is welded to the front and rear sides and the top of the sleeve tube (1) in sections.

4. The axle tube of the heavy-duty vehicle according to claim 1, characterized in that: The shaft tube (1) includes a tube body (101), a first bevel (102) and a second bevel (103). The tube body (101) is a hollow elongated tubular structure, and the four corners of the inner wall and the four corners of the outer wall of the tube body (101) are rounded. The first bevel (102) is inclined at the end of the tube body (101). The second bevel (103) is located on the inner wall of the tube body (101) and smoothly transitions with the first bevel (102).

5. The axle tube of the heavy-duty vehicle according to claim 4, characterized in that: The square sleeve (2) includes a sleeve body (201), a circular hole (202), and a third bevel (203). The sleeve body (201) is a hollow structure and is fixed in the inner cavity of the shaft tube (1). The circular hole (202) is opened through the sleeve body (201) and together with the sleeve body (201) forms an overall structure with an outer square and an inner circle. The third bevel (203) is inclined along the outer side wall of the sleeve body (201) and is located on the side of the sleeve body (201) near the shaft head (3).

6. The axle tube of the heavy-duty vehicle according to claim 5, characterized in that: The outer diameter of the sleeve (201) matches the inner diameter of the tube (101) in shape and size.

7. The axle tube of the heavy-duty vehicle according to claim 5, characterized in that: The shaft head (3) includes a main shaft section (301), a square piece (302), and an extension shaft section (303), and the main shaft section (301), the square piece (302), and the extension shaft section (303) are integrally formed; the extension shaft section (303) is disposed at the end of the main shaft section (301), and the square piece (302) is disposed on the main shaft section (301); the extension shaft section (303) is interference-fitted with the round hole (202), and the square piece (302) is circumferentially welded to the shaft tube (1) to form a whole.

8. The axle tube of the heavy-duty vehicle according to claim 7, characterized in that: The shaft head (3) further includes a threaded portion (304), a first recessed portion (305) and a second recessed portion (306). The threaded portion (304) is disposed at the end of the main shaft section (301) and is disposed opposite to the extension shaft section (303). The second recessed portion (306) is disposed inside the extension shaft section (303), and the first recessed portion (305) is disposed at the end of the main shaft section (301) away from the extension shaft section (303).

9. The axle tube of the heavy-duty vehicle according to claim 1, characterized in that: The shaft head (3) is a high-strength solid steel forging that has undergone quenching and tempering treatment.

10. The axle tube of a heavy-duty vehicle according to claim 1, characterized in that: Both sets of square sleeves (2) and both sets of shaft heads (3) are arranged symmetrically from left to right with the central axis of the shaft tube (1) as the reference.

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