Air suspension system and axle assembly

Abstract

This invention discloses an air suspension system and an axle assembly. The air suspension system includes a main beam, a bracket, an air spring, and an axle. The bracket is fixedly connected to the vehicle frame. The main beam includes a first end and a second end, with the first end pivotally connected to the bracket. The main beam consists of two opposing shells, each shell including a web, an upper flange, and a lower flange. The upper flanges of the two shells are welded together to form a top wall, and the lower flanges are welded together to form a bottom wall. A connecting portion is provided on the web, through which the axle passes. The portion of the top wall located at the upper edge of the connecting portion forms a transition section, and the height of the top wall gradually decreases from the first end towards the transition section. A mounting surface is formed on the top wall of the main beam between the transition section and the second end, and the air spring is mounted between the mounting surface and the vehicle frame. This invention meets the vehicle's lightweight requirements, while the air spring provides a larger installation space, allowing for the installation of larger-sized air springs to improve suspension performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicles, in particular to an air suspension system and an axle assembly. BACKGROUND

[0002] To improve the driving comfort and adapt to various complex road conditions, air suspension has gradually been popularized on commercial vehicles, which generally includes a main beam, a support, an air spring and an axle, the support is fixed on the frame of the vehicle, one end of the main beam is rotatably connected to the support through a pivot, the air spring is installed between the other end of the main beam above and the frame of the vehicle, and the axle is transversely arranged on the main beam. During the driving of the vehicle, the air spring is stretched and contracted to buffer the frame, so the air spring is the core component that determines the performance of the air suspension. Therefore, a larger size air spring is configured for the air suspension, and generally the distance between the end of the main beam for installing the air spring and the frame is large enough under the premise of meeting the performance of the suspension. The existing method is to set a bending structure on the part of the main beam between the axle and the air spring. The bent main beam forms a relatively low mounting surface on the side of the axle away from the support. The air spring is connected between the mounting surface and the frame. Although this structure can reduce the height of the mounting surface by bending and provide a larger mounting space for the air spring, setting the bending structure on the main beam increases the extension length of the main beam, which leads to the increase of the weight of the main beam, which is not conducive to the lightweight design requirement of the vehicle. At the same time, the bending structure usually requires a solid structure of the main beam, which further increases the overall weight of the air suspension. SUMMARY

[0003] The purpose of the present application is to provide an air suspension system which can provide a larger mounting space for the air spring while meeting the lightweight requirement of the vehicle.

[0004] The second purpose of the present application is to provide an axle assembly.

[0005] To achieve the above-mentioned first purpose, the present application adopts the following technical solutions:

[0006] The air suspension system comprises a main beam, a support, an air spring and an axle.

[0007] The support is fixedly connected to the frame.

[0008] The main beam includes a first end and a second end opposite to the first end. The first end of the main beam is pivotally connected to the support. The main beam consists of two opposing shells. Each shell includes a web, an upper flange formed by bending the top of the web, and a lower flange formed by bending the bottom of the web. The upper flanges of the two shells are welded together to form the top wall of the main beam, and the lower flanges of the two shells are welded together to form the bottom wall of the main beam. A connecting part is provided on the web. The connecting parts on the two webs are arranged opposite each other, and the axle passes through the connecting part of the two webs.

[0009] The portion of the top wall located at the upper edge of the connecting part forms a transition section. This transition section is an arc shape with a concave middle section, and the angle between the tangent of the transition section and the horizontal plane gradually decreases from the position near the first end to the position near the second end. The height of the top wall of the main beam gradually decreases from the first end to the transition section.

[0010] A mounting surface is formed on the top wall of the main beam at the position between the transition section and the second end, and an air spring is installed between the mounting surface and the frame.

[0011] The top wall of the main beam includes a transition section that connects to the transition section, and a support section that connects to the end of the transition section away from the transition section and extends to the second end. The width of the transition section gradually increases from the end that connects to the transition section to the end that connects to the support section. The upper surface of the support section forms an installation surface.

[0012] The width of the top wall of the main beam gradually increases from the first end toward the transition section and the position where it connects with the support section.

[0013] The height of the mounting surface gradually increases from the second end toward the first end, and the angle between the mounting surface and the horizontal plane is 0.8~6.3°.

[0014] The connecting part is provided with a through hole for the axle to pass through.

[0015] An axle seat is fitted on the outside of the axle, which is placed between the two webs. Both ends of the axle seat are respectively inserted into the through holes of the two connecting parts, and the outer periphery of the axle seat is welded and fixed to the edge of the through hole.

[0016] The bottom wall of the main beam, located between the first end and the connecting part, forms an arc-shaped structure with an upward convex part in the middle, and a relief recess is formed below the arc-shaped structure.

[0017] The air suspension system also includes a drum brake assembly, which includes a brake drum mounted on the end of the axle and located outside the main beam, a first brake backing plate fixed to the axle, two opposing brake shoes located inside the brake drum, friction pads fixed to the outside of the brake shoes, a camshaft, an adjusting arm, and a second brake chamber. One end of each brake shoe is pivotally connected to the first brake backing plate, and the other end of each brake shoe forms a free end. The extension direction of the camshaft is consistent with the extension direction of the axle, and one end of the camshaft is placed between the free ends of the two brake shoes and pushes the free ends of the two brake shoes when rotating. The other end of the camshaft is connected to one end of the adjusting arm, and the second brake chamber is connected to the other end of the adjusting arm to drive the adjusting arm to swing.

[0018] A through groove is provided on the bottom wall of the main beam. The adjusting arm is located inside the main beam and its other end extends out of the through groove to the outside of the main beam. The second brake chamber is installed on the bottom wall of the main beam through a connecting seat and is located in the clearance recess. The other end of the camshaft extends into the main beam through the web of the outer shell of the main beam to connect with one end of the adjusting arm.

[0019] The air suspension system also includes a disc brake assembly, which includes a wheel hub mounted on the end of the axle and located outside the main beam, a brake disc fixed on the wheel hub, a second brake backing plate fixed on the axle, a brake caliper mounted on the brake backing plate and mated to the brake disc, and a second brake chamber connected to the brake caliper to drive the brake caliper, the second brake chamber being located within an avoidance recess.

[0020] The support includes two side plates and an end plate connecting the two side plates away from the main beam. The portion of the two side plates near the main beam forms an opening. A pivot is installed between the two side plates. The first end of the main beam extends through the opening between the two side plates and is pivotally connected to the pivot.

[0021] The side panel includes a vertical extension section and an inclined section that bends from the top of the vertical extension section. The distance between the inclined sections of the two side panels gradually decreases from bottom to top. The top of the inclined section and the top of the end panel form a welded part for welding to the frame. The pivot is installed between the vertical extension sections of the two side panels.

[0022] A shock absorber is also connected between the support frame and the main beam, with both ends of the shock absorber hinged to the support frame and the main beam, respectively.

[0023] To achieve the second objective mentioned above, the present invention adopts the following technical solution:

[0024] The axle assembly includes the aforementioned air suspension system.

[0025] The beneficial effects of this invention are as follows:

[0026] The main beam of this invention is constructed by splicing two shells made of plates, forming a hollow structure that makes the main beam relatively lightweight, meeting the vehicle's lightweight requirements. Simultaneously, a gradually changing, arc-shaped transition section is formed on the top wall of the main beam near the axle connection point. This arc-shaped transition section not only lowers the mounting surface height but also increases the strength at the connection between the main beam and the axle. Furthermore, the height of the top wall of the main beam gradually decreases from the first end connecting the main beam to the bracket towards the transition section, further increasing the height difference between the mounting surface and the bracket. This, in turn, increases the distance between the mounting surface and the vehicle frame, providing a larger installation space for the air springs. Consequently, larger-sized air springs can be installed to improve suspension performance. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of one embodiment of the present invention;

[0028] Figure 2 for Figure 1 View from direction A;

[0029] Figure 3 for Figure 1 Schematic diagram of the installation of the main beam and axle;

[0030] Figure 4 for Figure 1 Structural diagram of the main beam;

[0031] Figure 5 for Figure 4 View from direction B;

[0032] Figure 6 This is a schematic diagram of another embodiment of the present invention;

[0033] Figure 7 This is a schematic diagram of the installation of the main beam and the support frame of the present invention;

[0034] Figure 8 for Figure 7 A schematic diagram of the structure of the central support. Detailed Implementation

[0035] The present invention will now be further described with reference to the accompanying drawings and specific embodiments:

[0036] like Figure 1 , 2As shown in Figures 3, 4, and 5, an air suspension system of the present invention includes a main beam 20, a bracket 40, an air spring 50, and an axle 30. The bracket 40 is fixed to the trailer frame 100. The main beam 20 is an irregularly shaped structure, including a first end 201 and a second end 202 opposite to the first end 201. The first end 201 of the main beam 20 is pivotally connected to the bracket 40. The air spring 50 connects the second end 202 of the main beam 20 and the frame 100. The main beam 20 is composed of two opposing shells 21, which are symmetrically arranged along the length of the main beam 20. The shells 21 can be made of sheet metal by stamping. Specifically, they include a web 211, an upper flange 212 formed by bending the top of the web 211, and a lower flange 213 formed by bending the bottom of the web 211. After the two shells 21 are arranged opposite each other, their upper flanges 212 are joined together. Welding is performed at the joint position of the two upper flanges 212, and the two upper flanges 212 are welded together along the length direction of the main beam 20. At the same time, the lower flanges 213 of the two shells 21 are joined together, and welding is performed at the joint position of the two lower flanges 213, and the two lower flanges 213 are welded together along the length direction of the main beam 20. In this way, the upper flanges 212 of the two shells 21 form the top wall of the main beam 20 after welding, and the lower flanges 213 of the two shells 21 form the bottom wall of the main beam 20 after welding. The webs 211 of the two shells 21 respectively form the side walls of the main beam 20. The main beam 20 forms a hollow structure made of plate. A connecting part 214 is provided on the web 211. The connecting part 214 is approximately located at the middle position of the extension direction of the web 211. The connecting parts 214 on the two webs 211 are arranged opposite each other. The axle 30 passes through the two connecting parts 214 to connect the axle 30 to the main beam 20. A transition section 216 is formed on the top wall of the main beam 20 at the upper edge of the connecting part 214. The transition section 216 is an arc shape with a concave middle section. The angle between the tangent of the transition section 216 and the horizontal plane gradually decreases from the position near the first end 201 to the position near the second end 202. Specifically, the angle between the tangent L1 at the midpoint a of the transition section 216 and the horizontal plane is greater than the angle between the tangent L2 at the midpoint b of the transition section 216 and the horizontal plane. The transition section extends with a concave arc trajectory, and the height of the transition section gradually decreases from point a to point b. At the same time, the height of the top wall of the main beam 20 gradually decreases from the first end 201 towards the transition section 216. In this way, a height difference is formed between the position where the first end 201 of the main beam 20 is connected to the bracket 40 and the position where the main beam 20 is connected to the axle 30. Since the top wall of the main beam 20 is set to gradually slope downward from the first end 201 towards the transition section 216, the above-mentioned height difference has a relatively large value. In addition, a mounting surface is formed on the top wall of the main beam 20 at a position between the transition section 216 and the second end 202. This mounting surface is used to match the mounting of the bottom connecting seat of the air spring 50, so that the air spring 50 can be installed between the mounting surface and the frame 100.

[0037] In this invention, the main beam 20 is formed by splicing two shells 21 made of plates, creating a hollow structure that makes the main beam 20 relatively lightweight, meeting the vehicle's lightweight requirements. Simultaneously, a gradually changing, arc-shaped transition section 216 is formed on the top wall of the main beam 20 near the connection point with the axle 30. This arc-shaped transition section 216 not only lowers the mounting surface height but also increases the strength at the connection between the main beam 20 and the axle 30. Furthermore, the height of the top wall of the main beam 20 gradually decreases from the first end 201 connecting the main beam 20 and the bracket 40 towards the transition section 216, further increasing the height difference between the mounting surface and the bracket 40. This, in turn, increases the distance between the mounting surface and the frame 100, providing a larger installation space for the air spring 50, thus enabling the installation of larger-sized air springs to improve suspension performance.

[0038] In a preferred embodiment, the top wall of the main beam 20 includes a transition portion 217 that connects to the transition section 216 and a support portion 218. The transition portion 217 connects to the lower end of the transition section 216, and the support portion 218 extends from the end of the transition portion 217 away from the transition section 216 to the second end 202 of the main beam 20. The width of the transition portion 217 gradually increases from the end connected to the transition section 216 towards the end connected to the support portion 218. The upper surface of the support portion 218 forms the aforementioned mounting surface. Viewed from above the main beam 20, the width of the transition portion 217 gradually increases from the end closer to the first end 216 towards the end connected to the support portion 218. The position of end 201 gradually increases towards the position of the second end 202. That is, the width of the top wall of the main beam 20 forms a gradually widening structure at the transition part 217. Thus, the width of the top wall of the main beam 20 at the support part 218 is larger than that at other positions, which in turn makes the mounting surface formed on the support part 218 have a relatively large width. The wider support surface can better accommodate the larger size of the air spring 50. At the same time, multiple sets of connection holes for fixing the air spring 50 can also be provided on the mounting surface to facilitate the installation of various different models of air springs. Meanwhile, due to the change in the width of the top wall, a bend 2111 is formed in the web 211 of the main beam 20 at the junction of the transition section 216 and the transition part 217. The bend 2111 strengthens the lateral stiffness of the web 211 and further improves the strength of the main beam 20. In addition, the width of the support part 218 is equidistant in the extension direction of the main beam 20. Therefore, a bend 2111 is also formed in the web 211 at the junction of the transition part 217 and the support part 218 to improve the strength of the main beam 20. In addition, the width of the top wall of the main beam 20 can be set to gradually increase from the first end 201 toward the transition part 217 and the position where it connects with the support part 218. That is, when viewed from above, the top wall of the main beam 20 has a conical structure. This allows the support part 218 to accommodate the installation of a larger-sized air spring 50, while the first end 201 of the main beam 20 has a relatively small width. This allows the first end 201 of the main beam 20 to fit well with the bracket 40, and also helps to reduce the weight of the main beam 20.

[0039] In this invention, the upper surfaces of the transition portion 217 and the support portion 218 can be considered as mounting surfaces, or only the upper surface of the support portion 218 can be considered as a mounting surface. In any case, the upper surface of the support portion 218 is flush with the upper surface of the transition portion 217. The height of the mounting surface gradually increases from the second end 202 towards the first end 201, and the angle α between the mounting surface and the horizontal plane is set to 0.8~6.3°. This results in the bottom surface of the air spring 50 being inclined downwards. During vehicle operation, the air suspension vibrates, keeping the mounting surface horizontal or approximately horizontal for a longer period. This ensures that the axial elastic stress of the air spring 50 is perpendicular or approximately perpendicular to the mounting surface on the main beam 20, thereby reducing the lateral stress on the air spring 50 and improving its service life. In a preferred embodiment, the angle α between the mounting surface and the horizontal plane can be set to 3.2°. Of course, in other embodiments, the mounting surface can be set to a horizontal state, that is, the angle between the tangent at the position where the transition section 216 connects with the transition part 217 and the horizontal plane is 0.

[0040] In another preferred embodiment, the present invention provides through holes 215 in the connecting portion 214 of the web 211, and the axle 30 passes through the through holes 215 in the two webs 211 to connect with the main beam 20. Furthermore, an axle seat 23 is fitted onto the outside of the axle 30, positioned between the two webs 211, with both ends of the axle seat 211 respectively passing through the through holes 215 in the two webs 211. The outer periphery of the axle seat 211 is welded and fixed to the edge of the through hole 215 at the position where it mates with the through hole 215. The axle seat 215 connects the two webs 211 laterally, improving the strength of the main beam 20 and facilitating the assembly of the main beam 20 and the axle 30.

[0041] See Figure 1 , 2As shown in Figures 3 and 4, the air suspension system of the present invention also includes a drum brake assembly. The drum brake assembly includes a brake drum 61, a first brake backing plate 31, two brake shoes 62, friction pads 63, a camshaft 64, an adjusting arm 65, and a second brake chamber 66. The brake drum 61 is mounted on the end of the axle 30 via bearings and is located on the outside of the main beam 20. The first brake backing plate 31 is fixed on the axle 30. The two brake shoes 62 are both located inside the brake drum 61 and are arranged opposite to each other. One end of the brake shoe 62 is pivotally connected to the first brake backing plate 31, and the other end forms a free end. The free ends of the two brake shoes 61 are opposite to each other. The friction pads 63 are mounted on the outside of the brake shoes 62. The camshaft 64... The extension direction of 4 is consistent with the extension direction of axle 30. One end of camshaft 64 has an S-shaped cam positioned between the free ends of the two brake shoes 62. The other end of camshaft 64 is connected to one end of adjusting arm 65. The second brake chamber 66 is connected to the other end of adjusting arm 65. During braking, the second brake chamber 66 can push the other end of adjusting arm 65 to swing, thereby causing adjusting arm 65 to drive camshaft 64 to rotate. When camshaft 64 rotates, the S-shaped cam on it can abut against the free ends of the two brake shoes 62, causing the two brake shoes 62 to swing outward, thereby causing the friction pads 63 on the outer side of brake shoes 62 to contact the inner surface of brake drum 61, thereby generating braking force. The portion of the bottom wall of the main beam 20 between the first end 201 and the connecting part 214 forms an arc-shaped structure with an upward convex middle section, thereby creating a clearance recess at the lower part of the arc-shaped structure below the main beam 20. A connecting seat 67 is fixed on the bottom wall of the main beam 20, and the second brake chamber 66 is installed on the connecting seat 67 and located within the clearance recess. A through groove is formed on the bottom wall of the main beam 20. Specifically, a recess 2131 can be formed on the lower flange 213 of each housing 21. After the lower flanges 213 of the two housings 21 are joined, the recesses 2131 on the lower flanges 213 of the two housings 21 form the aforementioned through groove. The aforementioned adjusting arm 6... The main body of 5 is placed in the internal space of the main beam 20. One end of the adjusting arm 65 is connected to the other end of the camshaft 64 in the internal space of the main beam 20. The other end of the adjusting arm 65 passes through the aforementioned through groove to the bottom wall of the main beam 20 and is connected to the push rod of the second brake chamber 66. The S-shaped cam of the camshaft 64 is placed between the free ends of the two brake shoes 62, and the other end of the camshaft 64 extends along the axial direction of the axle 30 toward the middle of the length direction of the axle 30. When the camshaft 64 extends to the main beam 20, the camshaft 64 passes through the web plate 211 of the outer side of the housing 21 on the main beam 20 and extends into the internal space of the main beam 20 to connect with one end of the adjusting arm 65.Because the main beam 20 of the present invention is a hollow structure formed by splicing two shells, the adjusting arm 65 can be placed inside the main beam 20, and the clearance recess below the bottom wall of the main beam 20 can be used to accommodate the second brake chamber 66. In this way, the camshaft 64 does not need to pass through or cross the main beam 20 as in the prior art, thus reducing the length of the camshaft 64. At the same time, the second brake chamber 66 is placed in the clearance recess below the main beam 20. In this way, the camshaft 64, adjusting arm 65, second brake chamber 66 and connecting seat 67 will not occupy the space between the two air suspension systems on the axle 30, which facilitates the layout of other vehicle components.

[0042] The air suspension system of the present invention is suitable not only for installing the aforementioned drum brake assembly, but also for installing disc brake assemblies, specifically, such as... Figure 6 As shown, the air suspension system of the present invention also includes a disc brake assembly, which includes a wheel hub 71, a brake disc 72, a second brake backing plate 32, a brake caliper 73, and a second brake chamber 74. The wheel hub is mounted on the end of the axle 30 via bearings and is located on the outside of the main beam 20. The brake disc 72 is fixedly connected to the wheel hub 71. The second brake backing plate 32 is fixed to the axle 30. The brake caliper 73 is mounted on the second brake backing plate 32 and matches the brake disc 72. The second brake chamber 74... The second brake chamber 74 is connected to the brake caliper 73. The brake caliper 73 can be driven by the second brake chamber 74 to clamp the brake disc 72 to generate braking force. The second brake chamber 74 is located in the clearance recess 24. The clearance recess 24 below the bottom wall of the main beam 20 provides installation space for the second brake chamber 74, so that the second brake chamber 74 can be placed below the main beam 20. This avoids the second brake chamber 74 occupying too much space in the axial direction of the axle 30, which facilitates the layout of other components on the vehicle.

[0043] See Figure 7 , 8As shown, the bracket 40 of the present invention includes two side plates 41 and an end plate 42. The bracket 40 is made of sheet metal by bending and stamping processes. The two side plates 41 are located on both sides of the bracket 40 respectively. The end plate 42 is connected between the side plates 41 away from the main beam 20. The portion between the side plates 42 and the side closer to the main beam 20 forms an opening 43. The width of the opening 43 is slightly larger than the width of the first end 201 of the main beam 20, so that the first end 201 of the main beam 20 can be inserted between the two side plates 41 through the opening 43. A pivot 402 is installed between the two side plates 41. After the first end of the main beam 20 extends into the space between the two side plates 41 through the opening 43, it is pivotally connected to the pivot 402, thereby pivotally connecting the first end of the main beam 20 to the bracket 40. The side plate 41 of the bracket 40 includes a vertical extension section 411 and an inclined section 412. The inclined section 412 is formed by bending the top of the vertical extension section 411. The distance between the inclined sections 412 of the two side plates 41 gradually decreases from bottom to top, making the bracket 40 form a structure that is narrow at the top and wide at the bottom. The top of the inclined section 412 and the top of the end plate 42 form a welded part 401, which is connected to the lower surface of the frame beam and welded to the frame beam. The aforementioned pivot 402 is disposed between the vertical extension sections 411 of the two side plates 41. A portion of the upper part of the side plate 41 is set as an inclined section 412, making the width of the top of the bracket 40 relatively small, so that the width of the welding part 401 can be adapted to the width of the frame beam, and the bracket 40 can be directly welded to the frame beam without the need for connecting parts between the bracket 40 and the frame. At the same time, the portion of the opening 43 located between the two vertical extension sections 411 has a relatively large width, which allows the first end 201 of the main beam 20 to be embedded, so that the first end 201 of the main beam 21 has sufficient width to ensure that the strength of the first end 201 of the main beam 21 meets the requirements.

[0044] like Figure 1 As shown, a shock absorber 60 is also connected between the bracket 40 and the main beam 20. One end of the shock absorber 60 is hinged to the bracket 40 and the other end is hinged to the main beam 20. During vehicle operation, the shock absorber 60 is used to buffer the sway of the main beam 20.

[0045] The axle assembly of the present invention includes the air suspension system described above. Other structures of the axle assembly are the same as those in the prior art and will not be described in detail here.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. 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. Such 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. An air suspension system, characterized by, The main beam, the support, the air spring and the axle; The support is fixedly connected to the frame; The main beam comprises a first end and a second end opposite to the first end, and the first end of the main beam is pivotally connected to the support; the main beam is composed of two opposite housings, each of which comprises a web, an upper flange bent from the top of the web and a lower flange bent from the bottom of the web, the upper flanges of the two housings are spliced to form a top wall of the main beam, and the lower flanges of the two housings are spliced to form a bottom wall of the main beam; a connecting portion is arranged on the web, and the connecting portions on the two webs are oppositely arranged; the axle passes through the connecting portions of the two webs; A transition section is formed on the part of the top wall located at the upper edge of the connecting portion, the transition section is in an arc shape with a concave middle portion, and the included angle between the tangent of the transition section and the horizontal plane gradually decreases from the position close to the first end to the position close to the second end; the height of the top wall of the main beam gradually decreases from the first end to the transition section; An installation surface is formed on the top wall of the main beam at the position between the transition section and the second end, and the air spring is installed between the installation surface and the frame; The top wall of the main beam comprises a transition portion connected to the transition section and a support portion connected to one end of the transition portion away from the transition section and extending to the second end; the width of the transition portion gradually increases from the end connected to the transition section to the end connected to the support portion; and the upper surface of the support portion forms the installation surface; The width of the top wall of the main beam gradually increases from the first end to the position where the transition portion and the support portion are connected; The height of the installation surface gradually increases from the second end to the position close to the first end, and the included angle between the installation surface and the horizontal plane is 0.8-6.3°.

2. The air suspension system of claim 1, wherein, A through hole is arranged on the connecting portion for the axle to pass through.

3. The air suspension system of claim 2, wherein, An axle seat is arranged outside the axle, the axle seat is arranged between the two webs, and the two ends of the axle seat pass through the through holes of the two connecting portions, and the outer periphery of the axle seat is welded and fixed to the edge of the through hole.

4. The air suspension system of claim 1, wherein, The part of the bottom wall of the main beam between the first end and the connecting portion is in an arc shape with an upward convex middle portion, and a recessed position is formed below the arc shape.

5. The air suspension system of claim 4, wherein, The air suspension system further comprises a drum brake assembly, which comprises a brake drum installed at the end of the axle and located outside the main beam, a first brake bottom plate fixed to the axle, two opposite brake shoes located in the brake drum, a friction plate fixed outside the brake shoe, a camshaft, an adjusting arm and a second brake air chamber; one end of each of the two brake shoes is pivotally connected to the first brake bottom plate, and the other end of each of the two brake shoes forms a free end; the extension direction of the camshaft is consistent with the extension direction of the axle, one end of the camshaft is arranged between the free ends of the two brake shoes and pushes the free ends of the two brake shoes when rotating, the other end of the camshaft is connected to one end of the adjusting arm, and the second brake air chamber is connected to the other end of the adjusting arm to drive the adjusting arm to swing.

6. The air suspension system of claim 5, wherein, A through slot is arranged on the bottom wall of the main beam, the adjusting arm is located inside the main beam and the other end of the adjusting arm passes through the through slot to the outside of the main beam, the second brake air chamber is installed on the bottom wall of the main beam through a connecting seat and located in the recessed position, and the other end of the camshaft passes through the web of the housing on the outer side of the main beam to extend into the main beam to be connected to one end of the adjusting arm.

7. The air suspension system of claim 4, wherein The air suspension system further comprises a disc brake assembly, which comprises a hub mounted on the end of the axle and located outside the main beam, a brake disc fixed on the hub, a second brake bottom plate fixed on the axle, a brake caliper mounted on the brake bottom plate and matched with the brake disc, and a second brake air chamber connected on the brake caliper to drive the brake caliper, which is located in the avoiding recess.

8. The air suspension system of claim 1, wherein, The bracket comprises two side plates and an end plate connected between the side plates away from the main beam, the part between the side plates close to the main beam forms an opening, a pivot is mounted between the two side plates, the first end of the main beam extends into the two side plates through the opening and is pivoted on the pivot.

9. The air suspension system of claim 8, wherein, The side plate comprises a vertical extension and an inclined section bent from the top of the vertical extension, the distance between the inclined sections of the two side plates gradually decreases from bottom to top, the top of the inclined section and the top of the end plate form a welding part welded with the frame, and the pivot is mounted between the vertical extensions of the two side plates.

10. The air suspension system of claim 1, wherein, A shock absorber is further connected between the bracket and the main beam, and the two ends of the shock absorber are respectively hinged on the bracket and the main beam.

11. An axle assembly characterized by, The air suspension system comprises the air suspension system according to any one of claims 1-10.

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