Commercial vehicle air spring with damping function and damping characteristic optimization method

Abstract

According to the commercial vehicle air spring with the damping function and the damping characteristic optimization method, the piston assembly with the damping hole is designed to be installed with the air bag, air flow is accurately controlled, the damping performance of a suspension system is improved, the volume ratio is adjusted, the damping force of the air spring is accurately adjusted, necessary supporting force can be provided, and the damping performance of the air spring is improved. And effective control over vibration and impact can be achieved through accurate control over the damping holes, the riding comfort and the driving stability of the vehicle are remarkably improved, and the characteristics of light weight and high damping are achieved.

Description

Technical Field

[0001] The invention relates to the field of shock absorbers, and in particular to a commercial vehicle air spring with a damping function and a damping characteristic optimization method. Background Art

[0002] The automobile vibration reduction system is mainly used to solve the impact of uneven road surface on the vehicle body, accelerate the attenuation of the vibration of the frame and body, and improve the driving stability of the vehicle. If the engine is likened to the "heart" of the car, and the transmission is the "central nervous system" of the car, then the chassis and suspension vibration reduction system are the "skeleton" of the car. The vibration reduction system not only determines the comfort and handling of a car, but also plays a great role in the safety of the vehicle. With the continuous improvement of people's requirements for comfort, the performance of the vibration reduction system has become one of the important indicators for measuring the quality and grade of the car.

[0003] The existing automobile vibration reduction system controls the vibration of the vehicle through the cooperation of the suspension and the shock absorber, that is, during the driving process of the vehicle, in order to offset and reduce the harsh impact caused by the uneven road surface, the lateral and longitudinal stability of the vehicle body can be ensured so that the vehicle can always maintain a large range of dynamic controllable posture within the free travel of the suspension design. Among them, air springs are used more and more frequently in existing commercial vehicles. The air spring is filled with compressed air in a sealed container, and its elastic effect is realized by using the compressibility of gas. The air spring has an ideal nonlinear elastic characteristic. After the height adjustment device is installed, the height of the vehicle body does not change with the increase or decrease of the load, the spring stiffness can be designed to be lower, and the ride comfort is good;

[0004] For example, the Mexican invention patent document with publication number "MX237751B" discloses an air spring shock absorber that can withstand extreme impact loads, has multiple configurations to adapt to different load applications, and has a long service life. The air spring shock absorber is mainly composed of an air bag and a piston assembly. The upper end of the air bag is connected to an end plate (corresponding to the number 2) for connecting to the vehicle body. Figure 1 It can be clearly seen that a damper (corresponding to reference numeral 20) is installed between the piston assembly and the airbag. The main function of the damper is to reduce the impact between the piston assembly and the airbag when the piston assembly moves upward, thereby protecting the air spring.

[0005] However, the damper has the following disadvantages in actual use:

[0006] 1. The damper in the prior art is not provided with any channel for gas fluid, so the gas will not flow between the airbag and the piston assembly, let alone pass through the damper. Therefore, not only does the damper not have the "damping" function, but the damping effect of the air spring is also poor.

[0007] 2. At the same time, with the development of the national economy, the demand for shock absorption of vehicles is also increasing, which makes the automobile manufacturers' requirements for damping force and lightweight of the suspension system more and more stringent. The damping force of the existing air spring is mainly provided by the shock absorber, which leads to the size and weight of the shock absorber being very large in order to provide the damping force, which undoubtedly increases the weight and cost of the suspension system. At the same time, since the main work is undertaken by the shock absorber, the internal wear of the shock absorber will also increase, affecting the service life. Therefore, a new air spring design is needed to overcome these problems and limitations of the existing technology.

[0008] 3. X's existing piston assembly is designed as an integrated structure, which has complex structure and manufacturing process and high cost. At the same time, it has poor interchangeability and cannot select the appropriate piston chamber volume according to customer requirements. It needs to be re-molded, which takes a long time and requires a large investment. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a commercial vehicle air spring with damping function and a damping characteristic optimization method in view of the deficiencies of the above-mentioned prior art.

[0010] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a commercial vehicle air spring with a damping function, comprising an airbag and a piston assembly, wherein the airbag is connected to a roll plate assembly at the top and to a piston assembly at the bottom, the roll plate assembly is connected to an air pipe joint, the air pipe joint is hollow and communicates with an airbag cavity inside the airbag, the piston assembly has a piston cavity, and at least one damping hole is provided on the piston assembly to connect the piston cavity with the airbag cavity, the aperture of the damping hole is 2-5.5 mm, and the volume ratio of the airbag cavity to the piston cavity is 1-8.

[0011] By adopting the above technical solution, an additional air chamber is realized by adding a piston cavity to the piston assembly, and the gas between the airbag cavity and the piston cavity is connected to each other by opening a damping hole, and the stiffness of the air spring with the additional air chamber is reduced, and the natural frequency of the suspension is effectively reduced, which can significantly increase the driving comfort and smoothness of the vehicle. At the same time, since the air spring with the damping hole has a larger damping angle and a better damping effect, it can replace the shock absorber to bear part of the damping force demand, thereby reducing the size of the shock absorber and effectively reducing the weight and cost of the suspension. At the same time, the damping force generated by the air spring can effectively reduce the internal wear of the shock absorber, extend the service life of the shock absorber, and reduce the use cost. The diameter of the damping hole is set to 2-5.5mm. The size of the damping hole directly affects the resistance of the gas flow, thereby affecting the size of the damping force, so as to achieve effective control of the gas flow between the piston cavity and the airbag cavity, and adapt to different needs of the suspension system. When the vehicle encounters road impact or vibration during driving, the gas inside the airbag will flow into the piston cavity through the damping hole according to the change in air pressure. The design of the damping hole limits the gas flow rate, so that the gas consumes part of the energy in the process of flowing through the damping hole. This energy consumption is converted into heat energy, thereby generating a damping force in the gas flow process. This damping force helps to slow down the airbag in the expansion and contraction. The damping hole can reduce the impact and vibration during the flight and improve the ride comfort of the vehicle. By adjusting the size and position of the damping hole, the damping effect can be finely adjusted to adapt to different driving conditions. When the airbag expands, as the air pressure inside the airbag increases, the airbag begins to expand, and the gas inside the airbag flows to the chamber of the piston assembly through the damping hole. The restrictive effect of the damping hole limits the gas flow rate, resulting in a damping effect, which reduces the impact and vibration during the expansion of the airbag. On the contrary, when the airbag contracts, as the air pressure inside the airbag decreases, the airbag begins to contract, and the gas outside or in the chamber of the piston assembly flows back to the inside of the airbag through the damping hole. The damping hole also limits the gas flow rate, resulting in a damping effect. To reduce the impact and vibration when the airbag is deflated, by setting the volume ratio of the airbag cavity and the piston cavity to 1-8, different damping forces can be obtained according to the finite element analysis of the influence of the ratio of different inner cavity volumes of the piston on the damping ratio, that is, when the volume of the airbag cavity is constant, the damping force of the air spring can be increased by increasing the volume in the piston cavity. Through this feature, the damping force of the air spring can be accurately adjusted by adjusting the volume ratio. The suspension system equipped with the air spring can not only provide the necessary supporting force, but also achieve effective control of vibration and impact through precise control of the damping hole, significantly improve the ride comfort and driving stability of the vehicle, and achieve the characteristics of lightweight and high damping.

[0012] The above-mentioned commercial vehicle air spring with damping function can be further configured as follows: the piston assembly includes a piston housing, a piston gas tank installed in the piston housing, and a mounting structure that fixes the piston gas tank to the piston housing; the damping hole is opened on the corresponding end surfaces of the piston gas tank and the piston housing, and the piston cavity in the piston gas tank is connected to the airbag cavity.

[0013] By adopting the above technical scheme, the piston air tank and the piston shell are set separately, and then assembled together through the installation structure. The installation structure can be riveted, screwed, clamped, etc., wherein the piston shell is used to assemble with the airbag and the subsequent suspension system to determine the stroke and load of the air spring, and the piston air tank is connected with the airbag cavity as the piston cavity to determine the stiffness and damping of the air spring and share the damping force, thereby solving the problem of the previous integrated setting, the need for welding of the piston, the complex structure, the high cost and the attenuation of the strength of the welding point. At the same time, the basic specifications of the air spring shells of conventional commercial vehicles are the same, so that when assembling air springs with different damping force requirements, one piston shell can be used to adapt to multiple piston air tanks of different volumes, greatly reducing the mold opening cost and adaptability.

[0014] The above-mentioned commercial vehicle air spring with damping function can be further configured as follows: the mounting structure includes a connecting bolt and a nut inserted between the piston housing and the piston gas tank, one end of the connecting bolt passes through the piston gas tank and the piston housing and is connected to the nut to lock the piston gas tank in the piston housing, the damping hole is arranged on the connecting bolt, and one end is connected to the airbag cavity, and the other end is connected to the piston cavity.

[0015] By adopting the above technical solution, the piston gas tank can be conveniently installed in the piston housing through connecting bolts and nuts, and the damping hole is set on the connecting bolts. In this way, by opening damping holes with different apertures on different connecting bolts, the size of the damping holes on different piston assemblies can be conveniently controlled, making the damping force adjustment simpler.

[0016] The above-mentioned commercial vehicle air spring with damping function can be further configured as follows: a plurality of reinforcing ribs or grooves are arranged around the inner wall of the piston housing corresponding to the piston gas tank, and a mounting fastener is arranged at one end of the piston gas tank away from the airbag.

[0017] By adopting the above technical solution, a plurality of reinforcing ribs are arranged on the inner wall of the piston shell, which neither affects the overall volume change of the piston gas tank nor transmits force to the piston tank body, thereby dispersing stress and ensuring the overall strength is reliable. Alternatively, a plurality of inwardly protruding grooves are arranged, so that the grooves converge to form an accommodating cavity for accommodating the piston gas tank, which laterally limits the piston gas tank to avoid shaking, and transmits force to the piston tank body, thereby dispersing stress and ensuring the overall strength is reliable.

[0018] The above-mentioned commercial vehicle air spring with damping function can be further configured as follows: the piston air tank includes an air tank shell and an inner ring wall arranged in the air tank shell, the inner ring wall is arranged in the center of the piston air tank and constitutes a first additional air chamber connected to the damping hole, and a second additional air chamber is formed between the inner ring wall and the air tank shell. An additional flow hole that connects the first additional air chamber with the second additional air chamber is opened on the inner ring wall, and the first additional air chamber and the second additional air chamber constitute the piston cavity.

[0019] With the above technical solution, the inner ring wall is used to divide the inside of the shell into two groups of additional air chambers, and cooperates with the additional flow holes to ensure that the gas flows along a stable path. When the airbag is compressed or stretched, the gas flows between the piston cavity and the airbag cavity through the damping hole. The design of the first additional air chamber and the second additional air chamber makes the gas flow path more complicated, increases the resistance to gas flow, and thus generates a greater damping force. The inner ring wall set in the center also increases the overall structural strength of the piston gas tank, avoiding the problem of inner wall depression caused by long-term in and out gas.

[0020] The above-mentioned commercial vehicle air spring with damping function can be further configured as follows: the bottom of the piston gas tank has a gas tank bottom plate, the gas tank bottom plate is welded to the inner ring wall and the gas tank shell, and cooperates with the gas tank shell to form the piston cavity, and an installation fastener is penetrated through the center of the gas tank bottom plate.

[0021] By adopting the above technical scheme, the gas tank bottom plate is connected to the inner ring wall of the piston gas tank and the gas tank shell to form a piston cavity together: the installation fastener passing through the center of the gas tank bottom plate is convenient for subsequent installation with the suspension system, ensuring the stability and correct position of the piston gas tank during the operation of the suspension system; the welding of the gas tank bottom plate with the inner ring wall and the gas tank shell ensures the structural integrity and sealing of the piston gas tank, prevents gas leakage, and facilitates the installation of connecting bolts and installation fasteners and the processing of additional flow holes.

[0022] The above-mentioned commercial vehicle air spring with damping function can be further configured as follows: a connecting flange is provided at the end of the piston housing facing the inside of the airbag, an anti-detachment hook is provided at the upper end of the connecting flange, a sealing sleeve at the lower end of the airbag is provided on the connecting flange, and a wire ring is connected to the lower end of the airbag, the connecting bolt is provided inside the connecting flange, and the end position is lower than the connecting flange.

[0023] By adopting the above technical scheme, the main function of the connecting flange is to provide a plane for sealing connection with the lower end of the airbag, so that the periphery of the connecting flange forms an airtight seal between the airbag and the anti-detachment hook, ensuring that the gas between the airbag and the piston assembly will not leak. At the same time, the connecting flange also plays a role in supporting and fixing the airbag, so that the airbag can be stably installed on the piston assembly. The main function of the anti-detachment hook is to prevent the airbag from falling off the connecting flange when the air pressure is too high or subjected to external impact, and a wire ring is arranged between the airbag and the connecting flange to enhance the connection reliability between the airbag and the connecting flange.

[0024] The above-mentioned commercial vehicle air spring with damping function can be further configured as follows: the rolling plate assembly includes an end plate, two groups of mounting holes are provided on the end plate, a group of air pipe joints are welded at each group of mounting holes, the outer ring of the end plate is provided with a riveted edge rolled toward the airbag, the upper end of the airbag is inserted into the riveted edge and the upper end of the airbag is connected to a wire ring.

[0025] By adopting the above technical solution, the matching relationship between the riveted edge and the upper end of the airbag can firmly fix the upper end of the airbag on the end plate, and a wire ring is arranged between the airbag and the end plate to enhance the connection reliability between the airbag and the end plate.

[0026] The above-mentioned commercial vehicle air spring with damping function can be further configured as follows: the piston housing includes a side wall, a top plate arranged at the end of the side wall facing the airbag for installing a connecting flange, and an opening arranged at the bottom of the side wall for installing a piston gas tank; the end of the side wall with the opening is provided with a side skirt portion extending gradually outward, the side skirt portion is integrally arranged with the side wall and the connecting flange, and an annular hollow groove is provided between the side skirt portion and the side wall.

[0027] By adopting the above technical scheme, the shape of the piston shell is roughly a cylinder with one end open, which is convenient for the installation of the piston gas tank. The piston shell is composed of a side, a top plate and a side skirt, wherein an annular hollow groove is provided between the side skirt and the side wall to reduce the weight of the piston assembly, thereby achieving lightweight while avoiding the problem of air holes caused by too thick sides during injection molding or die casting. The setting of the side skirt makes it possible for the air bag skin to flip to the position of the skirt when the air spring is compressed. At this time, the effective area will increase, and the corresponding bearing capacity will increase, so as to achieve the static elastic characteristics of a straight line at the front end and a curve at the rear end, so that in the initial compression stage, the stiffness of the air spring changes little, providing stable supporting force. As the compression increases, the side skirt of the piston shell begins to play a role, and the rolling of the air bag skin causes the effective area to increase, thereby providing nonlinearly increased bearing capacity in the later stage of compression. This design enables the air spring to provide different stiffnesses at different compression stages to adapt to different loads and driving conditions, providing better ride comfort and vehicle stability.

[0028] The above-mentioned commercial vehicle air spring with damping function can be further configured as: a damping characteristic optimization method of a commercial vehicle air spring with damping function, comprising the following steps:

[0029] S1. Obtain the load-bearing capacity, stiffness and working range requirements of the suspension system according to the specific needs of commercial vehicles;

[0030] S2. Use finite element analysis technology to simulate the load and displacement of the suspension system under different working conditions and determine the optimal size of the piston housing;

[0031] S3. According to the stiffness requirement of the suspension system confirmed in step S1, select the corresponding piston chamber volume to ensure that the stiffness of the air spring meets the design requirements;

[0032] S4. Design and manufacture piston bolts with damping holes of different diameters, the diameter of the damping holes ranges from 2 to 5.5 mm;

[0033] S5. Test the dynamic stiffness K of the air spring under different internal pressures in the test bench simulated working conditions t , and collect data, and then use the air spring dynamic stiffness and suspension dynamic stiffness conversion formula K = i 2 ·K t , obtain the suspension dynamic stiffness K, where K t is the air spring stiffness, K is the suspension stiffness, and i is the suspension lever ratio;

[0034] S6. The suspension dynamic stiffness obtained in step S5 is calculated using the suspension natural frequency formula: The natural frequencies of the air springs at different internal pressures are obtained to evaluate the effect, where m is the sprung mass of the vehicle and K is the suspension stiffness;

[0035] S7. Test the damping force of the air spring with different damping hole diameters under the test bench simulation working conditions. The test environment simulates the conversion of the air spring test frequency at the test speed of 0.13m / s and 0.52m / s, and the compression damping force and restoring damping force of the air spring with different damping hole diameters at the test speed;

[0036] S8. Use computer simulation technology to adjust the diameter of the damping hole and the volume ratio of the airbag cavity to the piston cavity to optimize the damping force of the suspension system;

[0037] S9. Install the optimized suspension system on the actual vehicle and conduct performance verification tests to ensure that it meets the design requirements.

[0038] Adopting the above technical scheme, step S1 determines the design parameters of the suspension system according to the specific needs of commercial vehicles, such as load-bearing capacity, suspension stiffness and working stroke. S2 uses finite element analysis technology to simulate the load and displacement of the suspension system under different working conditions to determine the optimal size of the piston housing to ensure the reliability and efficiency of the structure. S3 selects the appropriate piston cavity volume of the piston gas tank according to the stiffness requirements of the suspension system to ensure that the stiffness of the air spring meets the design requirements, thereby affecting the dynamic performance of the suspension. S4 designs and manufactures piston bolts with damping holes with different apertures. The aperture range of the damping hole is 2-5.5mm, which is used to control gas flow and generate damping force, and is convenient for direct installation on the corresponding piston housing and piston gas tank. S5 simulates the working conditions on the MTS test bench, GB / T 13061-2017 Technical Specifications for Air Springs for Commercial Vehicle Air Suspension tests the dynamic stiffness of air springs under different internal pressures and collects data. S6 calculates the suspension dynamic stiffness K through the dynamic stiffness conversion formula. It is concluded that the lower the dynamic stiffness, the lower the natural frequency, and the higher the comfort and smoothness of vehicle driving. In this way, the performance of air springs under different volume ratios and damping hole diameters of the suspension system can be evaluated to evaluate the impact of the air spring with air chamber on the vibration response of the suspension system. S7 is based on the shock absorber industry standard Q The test speeds of 0.13m / s and 0.52m / s specified in C / T491-2018 are used to convert the air spring test frequency. The MTS test bench is used to test the air spring damping force. The compression and recovery damping forces of the air springs with different damping hole diameters are tested to ensure that the suspension system can provide appropriate damping under various conditions. S8 uses computer simulation technology to adjust the diameter of the damping hole and the volume ratio of the airbag cavity to the piston cavity to optimize the damping force of the suspension system to adapt to different driving conditions. Through data comparison, under the same working conditions, Under the condition of low speed, the air spring with damping hole has a damping effect, which can share the damping force of the shock absorber part, thereby reducing the size of the shock absorber, effectively reducing the weight and cost of the suspension. At the same time, the damping force generated by the air spring can effectively slow down the internal wear of the shock absorber, extend the service life of the shock absorber, and thus reduce the user's maintenance cost. According to the finite element analysis of the influence of the ratio of different inner cavity volumes of the piston on the damping ratio, increasing the piston volume within a certain range can increase the damping ratio, and the greater the damping force; thus, it is concluded that the smaller the ratio of the airbag cavity volume to the piston cavity volume, the greater the damping force. S9 installs the optimized suspension system on the actual vehicle and conducts performance verification tests to ensure that it meets the design requirements, such as comfort, stability and handling. Through a complete set of commercial vehicle air spring damping characteristic optimization methods, by optimizing the design of the damping hole, the parameters required by customers can be selected and optimized in the most convenient way, reducing the weight and cost of the suspension system, extending the service life of the shock absorber, and thus reducing the user's maintenance cost. This method provides an innovative solution for the design and optimization of commercial vehicle suspension systems.

[0039] The beneficial effects of the present invention are:

[0040] 1. By optimizing the damping hole design, the air spring can more effectively absorb and dissipate vibration energy, reduce the natural frequency of the suspension system, and thus significantly improve the ride comfort of the vehicle.

[0041] 2. Air springs with damping holes provide a larger damping angle at different frequencies, which means that when faced with road impact or vibration, the suspension system can attenuate vibration faster and improve vehicle stability and handling.

[0042] 3. By reducing the reliance on the damping force of traditional shock absorbers, the weight of the suspension system can be reduced by replacing some of the damping force requirements of the shock absorbers, which helps improve fuel efficiency and reduce the overall weight of the vehicle.

[0043] 4. The damping force generated by the air spring can effectively slow down the internal wear of the shock absorber, extend the service life of the shock absorber, reduce maintenance costs, and also reduce manufacturing and maintenance costs.

[0044] 5. The design of the damping hole allows the air spring to easily adjust the aperture of the piston cavity and the damping hole to meet the damping force requirements of different specifications, improve the adaptability of the product, and reduce additional mold opening costs.

[0045] 6. By precisely controlling the aperture of the damping hole, the damping characteristics of the air spring can be adjusted to suit specific suspension requirements, thereby improving the overall performance of the suspension system.

[0046] The present invention will be further described below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a cross-sectional view of an embodiment of the present invention.

[0048] Figure 2 for Figure 1 Schematic diagram of the connection structure.

[0049] Figure 3 It is a three-dimensional schematic diagram of a piston assembly according to an embodiment of the present invention.

[0050] Figure 4 A three-dimensional schematic diagram of a piston assembly according to an embodiment of the present invention Figure 2 .

[0051] Figure 5 It is a bottom view of the piston housing according to an embodiment of the present invention.

[0052] Figure 6 It is a damping angle curve diagram of an embodiment of the present invention without a damping hole.

[0053] Figure 7It is a damping angle curve diagram of an embodiment of the present invention with a φ2 damping hole.

[0054] Figure 8 It is a damping angle curve diagram of an embodiment of the present invention with a φ4 damping hole.

[0055] Fig. 9 It is a damping angle curve diagram of an embodiment of the present invention with a φ5.5 damping hole.

[0056] Fig.10 It is a volume ratio-damping ratio curve diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0057] like Figure 1-Figure 5 As shown, a commercial vehicle air spring with a damping function comprises an airbag 1 and a piston assembly. The airbag 1 is connected to a coil assembly at the top and to a piston assembly at the bottom. The coil assembly is connected to an air pipe joint 2, which is hollow and communicates with an airbag cavity V1 inside the airbag 1. The piston assembly has a piston cavity V2. The piston assembly is provided with at least one damping hole 50 for connecting the piston cavity V2 with the airbag cavity V1. The aperture of the damping hole 50 is 2-5.5 mm. The volume ratio of the airbag cavity V1 to the piston cavity V2 is 1-8. The piston assembly comprises a piston housing 3, a piston gas tank 4 installed in the piston housing 3, and a connecting bolt 5 and a nut 51 for fixing the piston gas tank 4 with the piston housing 3. One end of the connecting bolt 5 passes through the piston gas tank 4 and the piston housing 3 and is connected to the nut 5 to lock the piston gas tank 4 in the piston housing 3. The damping hole 50 is arranged at the center of the connecting bolt 5, and one end is connected to the airbag cavity V1, and the other end is connected to the piston cavity V2.

[0058] like Figure 1-Figure 5As shown, the piston housing 3 includes a side wall 31, a top plate 32 arranged at one end of the side wall 31 facing the airbag 1 and having a connecting flange 321 for installation, an opening 33 arranged at the bottom of the side wall 31 for the piston gas tank 4 to be installed, and one end of the side wall 31 having the opening 33 is provided with a side skirt 311 extending gradually outward, the side skirt 311 is integrally arranged with the side wall 31 and the connecting flange 321, and an annular hollow groove 312 is provided between the side skirt 11 and the side wall 31. The setting of the side skirt 11 makes it possible that when the air spring is compressed, the bag skin of the airbag 1 will turn over to the position of the side skirt 11. At this time, the effective area will increase, and the corresponding bearing capacity will increase, so as to realize the static elastic characteristics of a straight line at the front end and a curve at the rear end, so that in the initial compression stage, the stiffness of the air spring changes little, providing a stable supporting force, and as the compression increases, the side skirt 11 of the piston housing 3 begins to play a role The rolling of the airbag skin of the airbag 1 causes the effective area to increase, thereby providing a nonlinearly increased load-bearing capacity in the later stage of compression. This design enables the air spring to provide different stiffnesses in different compression stages to adapt to different loads and driving conditions, providing better ride comfort and vehicle stability. A plurality of reinforcing ribs 34 are arranged around the inner wall of the piston housing 3 corresponding to the piston gas tank 4. An installation fastener 35 is provided at the end of the piston gas tank 4 away from the airbag 1 to facilitate subsequent assembly with the suspension system. An anti-detachment hook 322 is provided at the upper end of the connecting flange 321. The sealing sleeve at the lower end of the airbag 1 is arranged on the connecting flange 31, and a wire ring 30 is connected to the lower end of the airbag 1. The connecting bolt 5 is arranged inside the connecting flange 31, and the end position is lower than the connecting flange 31, so that when the airbag 1 retracts excessively, the skin will also be supported by the connecting flange 31, which will not affect the air inlet and outlet of the damping hole 50.

[0059] like Figure 1-Figure 2 As shown, the piston gas tank 4 includes a gas tank shell 41 and an inner ring wall 42 arranged in the gas tank shell 41, the inner ring wall 42 is arranged at the center of the piston gas tank 4 and constitutes a first additional gas chamber V21 connected to the damping hole 50, and a second additional gas chamber V22 is formed between the inner ring wall 42 and the gas tank shell 41. An additional flow hole 421 for connecting the first additional gas chamber V21 with the second additional gas chamber V22 is opened on the inner ring wall 42, and the first additional gas chamber V21 and the second additional gas chamber V21 constitute a total piston chamber V2. The bottom of the piston gas tank 4 has a gas tank bottom plate 43, which is welded to the inner ring wall 42 and the gas tank shell 41, and cooperates with the gas tank shell 41 to form the piston chamber V2, and a mounting fastener 35 is penetrated at the center of the gas tank bottom plate V2.

[0060] like Figure 1 , Figure 2As shown, the rolling plate assembly includes an end plate 6, which is provided with two groups of mounting holes 61, and each group of mounting holes 61 is welded with a group of air pipe joints 2. The outer ring of the end plate is provided with a riveted edge 62 rolled toward the airbag 1, and the upper end of the airbag 1 is inserted into the riveted edge 62 and the upper end of the airbag 1 is connected to a wire ring 30, thereby enhancing the reliability of the connection between the airbag 1 and the end plate 6.

[0061] like Figure 6-Figure 9 As shown, the difference between the present invention and the prior art is that an additional piston chamber is added, and the diameter of the damping hole can be controlled so that the air spring can bear part of the damping force requirement. The influence of the additional piston chamber on the stiffness of the air spring is shown in the following table:

[0062]

[0063]

[0064] As can be seen from the table above, according to GB / T 13061-2017 Technical Specifications for Air Springs for Commercial Vehicle Air Suspensions, the dynamic stiffness values ​​of air springs with and without piston chambers are tested respectively. The dynamic stiffness K of air springs under different internal pressures of air springs is t , the conversion formula of air spring dynamic stiffness and suspension dynamic stiffness is K=i 2 ·K t , obtain the suspension dynamic stiffness K, where K t is the air spring stiffness, K is the suspension stiffness, i is the suspension lever ratio, the suspension dynamic stiffness K is related to the air spring stiffness K t It is a proportional relationship, and according to the suspension natural frequency formula:

[0065]

[0066] The natural frequency of the air spring under different internal pressures, where m is the sprung mass of the vehicle and K is the stiffness of the suspension. The test results are consistent with the formula. The stiffness of the air spring with a piston cavity is significantly reduced, which can effectively reduce the natural frequency of the suspension and significantly increase the driving comfort and smoothness of the vehicle.

[0067] Then, the MTS test bench was used to simulate the vehicle operating conditions and test the damping angle values ​​of air springs with different damping holes and full piston chambers at different frequencies and amplitudes. The damping angle reflects the degree of energy loss of the vibration system in one cycle. The larger the damping angle, the faster the energy loss of the system, the faster the amplitude decays, the better the stability of the system, and the larger the damping angle value, the better the damping effect.

[0068] 1. See Figure 6 The damping angle curve and the frequency amplitude data table of the damping angle curve and the non-damping hole are as follows:

[0069]

[0070]

[0071] 2. See Figure 7 The damping angle curve and the frequency amplitude data table of the damping hole with an aperture of 2mm are as follows:

[0072]

[0073] 3. See also Figure 8 The damping angle curve and the frequency amplitude data table of the damping hole with an aperture of 4mm are as follows:

[0074]

[0075]

[0076] IV. See Fig. 9 The damping angle curve and the frequency amplitude data table of the damping hole with an aperture of 5.5 mm are as follows:

[0077]

[0078] Through the data, it is found that the difference between the damping angle of the air spring with damping holes and the air chamber with full air flow is large. The damping angle of the air spring with damping holes is larger and the damping effect is better (0-15Hz is the excitation frequency range of the road surface for commercial vehicles). The maximum damping angle distribution area corresponding to different aperture sizes is different, for example Figure 7 As shown, when the diameter of the damping hole is 2mm, the damping angle of the air spring is larger at low frequency and small amplitude, but smaller at high frequency and large amplitude. This indicates that at low frequency and amplitude, that is, when the vehicle slowly passes over small road irregularities or is subjected to a small impact, the damping hole allows air to flow at a relatively slow speed, and the damping angle is relatively large. A large damping angle means fast energy dissipation and rapid vibration decay, thus providing better comfort and stability. In the case of high frequency and large amplitude, that is, when the vehicle quickly passes over a large road unevenness or is subjected to a large impact, the air flow velocity increases and the flow limiting effect of the damping hole becomes more obvious, resulting in a decrease in the damping angle. A small damping angle means slow energy dissipation and slow vibration decay, which reduces ride comfort because the suspension system cannot quickly absorb and dissipate vibration energy. By analyzing the normal driving conditions of the sales models and adjusting the aperture of the damping hole, the damping characteristics of the air spring can be fine-tuned to adapt to different driving conditions and road characteristics. This design allows the air spring to provide appropriate damping force at different vibration frequencies, thereby optimizing the vehicle's ride comfort and handling.

[0079] Then, the MTS test bench is used to simulate the vehicle operating conditions and the air spring test frequency is converted according to the test speeds of 0.13m / s and 0.52m / s specified in the shock absorber industry standard QC / T491-2018. The compression damping force and restoring damping force of the air spring damping force at speeds of 0.13m / s and 0.52m / s are tested, as shown in the following table:

[0080] Test speed (m / s) Damping aperture(mm) Compression damping force(N) Restoring damping force(N) 0.13 2 634 608 0.13 4 595 577 0.13 5.5 573 573 0.52 2 1157 1095 0.52 4 1242 1209 0.52 5.5 1318 1239

[0081] Through data comparison, under the same working conditions, the air spring with damping holes has a damping effect and can share the damping force of the shock absorber, thereby reducing the size of the shock absorber and effectively reducing the weight and cost of the suspension. At the same time, the damping force generated by the air spring can effectively reduce the internal wear of the shock absorber and extend the service life of the shock absorber, thereby reducing the user's maintenance costs.

[0082] For example, the damping force requirements for commercial vehicles are: compression damping force: damping force at 0.13m / s: 1305±20%N; damping force at 0.52m / s: 3860±20%N; restoring damping force: damping force at 0.13m / s: 1532±20%N; damping force at 0.52m / s: 4669±20%N. When there is no air spring with damping hole, the damping force demand will have to be fully borne by the shock absorber. By setting the existing air spring The piston cavity controls the aperture of the damping hole. At this time, a φ4 air spring is selected to share part of the damping force requirement. At this time, the shock absorber only needs to bear the damping force requirements of 0.13m / s compression damping force 710±20%N, restoring damping force 955±20%N, 0.52m / s compression damping force 2618±20%N, and restoring damping force 3460±20%N. This can greatly reduce the size of the shock absorber, effectively reduce the weight and cost of the suspension, and meet the needs of lightweight and high damping.

[0083] See also Fig.10 The volume ratio-damping ratio curve and the volume ratio and damping ratio comparison data table are as follows

[0084] Volume ratio 1 2 3 4 5 6 7 8 Damping ratio 0.2 0.26 0.3 0.335 0.36 0.38 0.39 0.4

[0085] According to the finite element analysis of the effect of the ratio of different inner cavity volumes of the piston on the damping ratio, increasing the piston volume within a certain range can increase the damping ratio, and the greater the damping force, it can be concluded that the smaller the ratio of the airbag chamber volume to the piston chamber volume, the greater the damping force. For example, the airbag chamber volume is about 9.5L, and the piston chamber volume is about 2.15L, then the volume ratio is 4.419, and the damping ratio is 3.3. At this time, it is only necessary to replace the piston gas tank of different specifications and sizes. When the airbag chamber volume remains unchanged, increasing the piston chamber volume will increase the damping force, thereby achieving convenient damping force fine-tuning.

[0086] A method for optimizing the damping characteristics of a commercial vehicle air spring with a damping function comprises the following steps:

[0087] S1. According to the specific needs of commercial vehicles, the bearing capacity of the suspension system is determined to be 8000kg±200kg, the stiffness is 10000±500N / mm, the compression damping force: the damping force at 0.13m / s: 1305±20%N; the damping force at 0.52m / s: 3860±20%N; the restoring damping force: the damping force at 0.13m / s: 1532±20%N; the damping force at 0.52m / s: 4669±20%N;

[0088] S2. Using finite element analysis technology, simulate the load and displacement of the suspension system under different working conditions and determine the optimal size of the piston housing to be 250mm in diameter and 150mm in height;

[0089] S3. According to the stiffness requirements of the suspension system confirmed in step S1, the airbag chamber volume is 9.5L, and according to the finite element analysis of the volume ratio, the piston chamber volume is confirmed to be 2.15L;

[0090] S4. Assemble the damping hole piston bolt with a diameter range of 4 mm for the damping hole;

[0091] S5. Test the dynamic stiffness K of the air spring under different internal pressures in the test bench simulated working conditions t 200N / mm, and collect data, and then use the air spring dynamic stiffness and suspension dynamic stiffness conversion formula K=i 2 ·K t , obtain the suspension dynamic stiffness K, where K t is the air spring stiffness, K is the suspension stiffness 800N / mm, i is the suspension lever ratio 2;

[0092] S6. The suspension dynamic stiffness obtained in step S5 is calculated using the suspension natural frequency formula: The natural frequency of the air spring under different internal pressures is obtained to evaluate the effect. The sprung mass m of the vehicle is 2000kg, K is the suspension stiffness 800N / mm, and the natural frequency is 0.0159Hz, which meets the industry standard.

[0093] S7. Test the damping force of the air spring with different damping hole diameters under the test bench simulation working conditions. The test environment simulates the air spring test frequency conversion at the test speed of 0.13m / s and 0.52m / s. The compression damping force of the air spring with a damping hole of 4mm diameter is:

[0094] Damping force at 0.13m / s: 595N; Damping force at 0.52m / s: 1242N; Restoring damping force: Damping force at 0.13m / s: 577N; Damping force at 0.52m / s: 1209N, which can bear most of the damping force indicators. At this time, the shock absorber only needs to bear the damping force requirements of 0.13m / s compression damping force 710±20%N, restoring damping force 955±20%N, 0.52m / s compression damping force 2618±20%N, and restoring damping force 3460±20%N;

[0095] S8. Using computer simulation technology, the diameter of the damping hole is simulated to be 4 mm and the volume ratio of the airbag cavity to the piston cavity is 4.419, so that the damping force of the suspension system meets the optimization standard;

[0096] S9. Install the optimized suspension system on the actual vehicle and conduct performance verification tests to ensure that it meets the design requirements.

Claims

1. A commercial vehicle air spring with a damping function, comprising an airbag and a piston assembly, wherein the airbag is connected to a roll plate assembly at the top and to a piston assembly at the bottom, wherein the roll plate assembly is connected to an air pipe joint, wherein the air pipe joint is hollow and communicates with an airbag cavity inside the airbag, and wherein: The piston assembly has a piston cavity, and at least one damping hole connecting the piston cavity and the airbag cavity is formed on the piston assembly. The diameter of the damping hole is 2-5.5 mm, and the volume ratio of the airbag cavity to the piston cavity is 1-8.

2. The commercial vehicle air spring with damping function according to claim 1, characterized in that: The piston assembly includes a piston shell, a piston gas tank installed in the piston shell, and a mounting structure that fixedly connects the piston gas tank to the piston shell. The damping hole is opened on the corresponding end faces of the piston gas tank and the piston shell, and connects the piston cavity in the piston gas tank with the airbag cavity.

3. The commercial vehicle air spring with damping function according to claim 2, characterized in that: The mounting structure includes a connecting bolt and a nut which are passed through the piston housing and the piston gas tank. One end of the connecting bolt passes through the piston gas tank and the piston housing and is connected to the nut to lock the piston gas tank in the piston housing. The damping hole is arranged on the connecting bolt, and one end is communicated with the airbag cavity, and the other end is communicated with the piston cavity.

4. The commercial vehicle air spring with damping function according to claim 3, characterized in that: A plurality of reinforcing ribs or slots are arranged around the inner wall of the piston housing corresponding to the piston gas tank, and a mounting fastener is arranged at one end of the piston gas tank away from the airbag.

5. The commercial vehicle air spring with damping function according to claim 3, characterized in that: The piston gas tank includes a gas tank shell and an inner ring wall arranged in the gas tank shell. The inner ring wall is arranged at the center of the piston gas tank and constitutes a first additional air chamber connected to the damping hole. A second additional air chamber is formed between the inner ring wall and the gas tank shell. An additional flow hole connecting the first additional air chamber with the second additional air chamber is opened on the inner ring wall. The first additional air chamber and the second additional air chamber constitute the piston cavity.

6. The commercial vehicle air spring with damping function according to claim 5, characterized in that: The bottom of the piston gas tank is provided with a gas tank bottom plate, which is welded to the inner ring wall and the gas tank shell and cooperates with the gas tank shell to form the piston cavity. A mounting fastener is penetrated at the center of the gas tank bottom plate.

7. A commercial vehicle air spring with damping function according to any one of claims 2 to 6, characterized in that: A connecting flange is provided at the end of the piston housing facing the inside of the airbag, an anti-disconnection hook is provided at the upper end of the connecting flange, a sealing sleeve at the lower end of the airbag is provided on the connecting flange, and a wire ring is connected to the lower end of the airbag, the connecting bolt is arranged inside the connecting flange, and the end position is lower than the connecting flange.

8. A commercial vehicle air spring with damping function according to any one of claims 1 to 6, characterized in that: The rolling plate assembly includes an end plate, which is provided with two groups of mounting holes, each group of mounting holes is welded with a group of air pipe joints, the outer ring of the end plate is provided with a riveted edge rolled toward the airbag, the upper end of the airbag is inserted into the riveted edge and the upper end of the airbag is connected to a wire ring.

9. The commercial vehicle air spring with damping function according to claim 7, characterized in that: The piston housing includes a side wall, a top plate arranged at one end of the side wall facing the airbag and having a connecting flange for installation, an opening arranged at the bottom of the side wall for installation of the piston gas tank, and a side skirt portion extending gradually outward at one end of the side wall with the opening. The side skirt portion is integrally arranged with the side wall and the connecting flange, and an annular hollow groove is provided between the side skirt portion and the side wall.

10. A method for optimizing damping characteristics of a commercial vehicle air spring with damping function according to any one of claims 1 to 6, characterized in that: The steps include: S1. Obtain the load-bearing capacity, stiffness and working range requirements of the suspension system according to the specific needs of commercial vehicles; S2. Use finite element analysis technology to simulate the load and displacement of the suspension system under different working conditions and determine the optimal size of the piston housing; S3. According to the stiffness requirement of the suspension system confirmed in step S1, select the corresponding piston chamber volume to ensure that the stiffness of the air spring meets the design requirements; S4. Design and manufacture piston bolts with damping holes of different diameters, the diameter of the damping holes ranges from 2 to 5.5 mm; S5. Test the dynamic stiffness K of the air spring under different internal pressures in the test bench simulated working conditions t , and collect data, and then use the air spring dynamic stiffness and suspension dynamic stiffness conversion formula K = i 2 ·K t , obtain the suspension dynamic stiffness K, where K t is the air spring stiffness, K is the suspension stiffness, and i is the suspension lever ratio; S6. The suspension dynamic stiffness obtained in step S5 is calculated using the suspension natural frequency formula: The natural frequencies of the air springs at different internal pressures are obtained to evaluate the effect, where m is the sprung mass of the vehicle and K is the suspension stiffness; S7. Test the damping force of the air spring with different damping hole diameters under the test bench simulation working conditions. The test environment simulates the conversion of the air spring test frequency at the test speed of 0.13m / s and 0.52m / s, and the compression damping force and restoring damping force of the air spring with different damping hole diameters at the test speed; S8. Use computer simulation technology to adjust the diameter of the damping hole and the volume ratio of the airbag cavity to the piston cavity to optimize the damping force of the suspension system; S9. Install the optimized suspension system on the actual vehicle and conduct performance verification tests to ensure that it meets the design requirements.

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