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

Abstract

The present application relates to a kind of commercial vehicle air spring with damping function and damping characteristic optimization method, by designing the piston assembly with damping hole and air bag installation, accurately control gas flow, improve suspension system damping performance, and adjust volume ratio to the damping force of air spring Precise regulation, not only can provide necessary support force, but also can be realized to the effective control of vibration and impact by the accurate control of damping hole, significantly improve the ride comfort and driving stability of vehicle, realize the characteristics of light weight, high damping.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of shock absorber, in particular to a method for optimizing damping characteristics of air spring and damping function of commercial vehicle. BACKGROUND

[0002] Automobile damping system is mainly used to solve the impact of uneven road to the body, to accelerate the damping of the frame and the body vibration, to improve the driving stability of the automobile. If the engine is compared to the "heart" of the car, the transmission is the "central nervous system" of the car, then the chassis and suspension damping system is the "skeleton framework" of the car, the damping system not only determines the comfort and handling of a car, but also plays a decisive role in the safety of the vehicle, with the continuous improvement of people's requirements for comfort, the performance of damping system has become one of the important indicators to measure the quality and grade of the car.

[0003] The existing automobile damping system controls the damping of the vehicle through the cooperation of the suspension and the shock absorber, that is, in the process of driving, in order to offset the impact of uneven road, it can also ensure the lateral and longitudinal stability of the vehicle body, 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 spring is used more and more frequently in existing commercial vehicles. Air spring is filled with compressed air in a sealed container, which uses the compressibility of gas to realize its elastic effect. Air spring has ideal nonlinear elastic characteristics. After installing height adjustment device, the height of the vehicle body does not change with the increase and decrease of load, and the spring stiffness can be designed to be lower, and the ride comfort is good.

[0004] The Mexican invention patent document with publication number "MX237751B" discloses an air spring shock absorber which can withstand extreme impact load, has multiple configurations to adapt to different load applications, and has long service life. It is mainly composed of a gas bag and a piston assembly. The upper end of the gas bag is connected with an end plate (corresponding to reference number 2) for connecting with the vehicle body. According to the attached drawings of the disclosure document, Figure 1 It can be clearly seen that a damper (corresponding to reference number 20) is installed between the piston assembly and the gas bag. The main function of the damper is to reduce the impact between the piston assembly and the gas bag when the piston assembly moves upward, and to protect 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 hole for gas flow, so the gas cannot flow between the gas bag and the piston assembly, and cannot pass through the damper. Therefore, the damper does not have the function of "damping", and the damping effect of the air spring is poor.

[0007] 2、With the development of the national economy, the demand for damping of vehicles is also increasing, which makes the automobile manufacturers more and more strict on the damping force and lightweight demand of the suspension system. 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 damping force, which undoubtedly increases the weight and cost of the suspension system. At the same time, since the shock absorber mainly bears the work, the internal wear of the shock absorber will also be intensified, affecting the service life. Therefore, a new air spring design is needed to overcome the problems and limitations of the prior art.

[0008] 3、The existing piston assembly is designed as an integral structure, and the structure and manufacturing process are complex and high in cost, and the interchangeability is poor, and the appropriate piston cavity volume cannot be selected according to the customer's requirements, and the mold needs to be re-opened, the cycle is long and the investment is large. SUMMARY

[0009] The technical problem to be solved by the present application is to provide a commercial vehicle air spring with damping function and a damping characteristic optimization method.

[0010] To achieve the above purpose, the present application provides the following technical scheme: a commercial vehicle air spring with damping function, comprising an air bag, a piston assembly, the upper part of the air bag is connected with a roll plate assembly, the lower part is connected with the piston assembly, the roll plate assembly is connected with a gas pipe joint, the gas pipe joint is hollow and communicates with the air bag cavity inside the air bag, the piston assembly has a piston cavity, at least one damping hole for connecting the piston cavity and the air bag cavity is formed on the piston assembly, the diameter of the damping hole is 2-5.5mm, and the volume ratio of the air bag cavity and the piston cavity is 1-8.

[0011] The technical scheme is adopted, the piston cavity is added on the piston assembly, the additional air chamber is realized, the gas between the air bag cavity and the piston cavity is communicated through the damping hole, the stiffness of the air spring with the additional air chamber is reduced, the inherent frequency of the suspension is effectively reduced, the driving comfort and smoothness of the vehicle can be significantly improved, and since the damping angle of the air spring with the damping hole is larger and the damping effect is better, a part of the damping force demand can be borne by the shock absorber, so that the size of the shock absorber can be reduced, the weight and cost of the suspension are effectively reduced, the damping force generated by the air spring can effectively slow down the internal wear of the shock absorber, the service life of the shock absorber is prolonged, and the user maintenance cost is reduced, wherein the diameter of the damping hole is 2-5.5 mm, the size of the damping hole directly affects the resistance of gas flow, thereby affecting the size of the damping force, so as to realize effective control of the gas flow between the piston cavity and the air bag cavity, adapt to different requirements of the suspension system, when the vehicle encounters road impact or vibration during driving, the gas in the air bag will flow into the piston cavity through the damping hole according to the change of air pressure, the design of the damping hole limits the flow rate of the gas, so that the gas consumes part of the energy during the flow through the damping hole, and the energy consumption is converted into heat energy, thereby generating a damping force during the gas flow, which helps to slow down the impact and vibration of the air bag during stretching and contraction, improves the riding comfort of the vehicle, and adjusts the size and position of the damping hole to finely adjust the damping effect to adapt to different driving conditions. When the air bag expands, the air bag starts to expand as the air pressure in the air bag rises, the gas in the air bag flows to the chamber of the piston assembly through the damping hole, and the limiting effect of the damping hole limits the flow rate of the gas, thereby generating a damping effect and slowing down the impact and vibration of the air bag during expansion. On the contrary, when the air bag contracts, the air bag starts to contract as the air pressure in the air bag decreases, and the gas in the outside or the chamber of the piston assembly flows back to the air bag through the damping hole. The damping hole also limits the flow rate of the gas, thereby generating a damping effect and slowing down the impact and vibration of the air bag during contraction. By setting the volume ratio of the air bag cavity to the piston cavity to be 1-8, different damping forces can be obtained according to the influence of the volume ratio of the piston cavity on the damping ratio through finite element analysis, that is, when the volume of the air bag cavity is constant, increasing the volume of the piston cavity can increase the damping force of the air spring. The suspension system loaded with the air spring can not only provide necessary support force, but also realize effective control of vibration and impact through precise control of the damping hole, significantly improve the riding comfort and driving stability of the vehicle, and realize the characteristics of light weight and high damping.

[0012] The aforementioned 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 inside the piston housing, and an installation structure that fixes the piston gas tank to the piston housing; the damping hole is opened on the corresponding end face of the piston gas tank and the piston housing, and connects the piston chamber inside the piston gas tank with the air chamber.

[0013] By adopting the above technical solution, the piston air tank and piston housing are set separately and then assembled together by an installation structure. The installation structure can be riveted, screwed, snap-fitted, etc. The piston housing is used to determine the stroke and load of the air spring when assembled with the airbag and subsequent suspension system. The piston air tank, as the piston chamber and airbag chamber, determines the stiffness and damping of the air spring and shares the damping force. This solves the problems of the previous integrated setting, where the piston needed to be welded, the structure was complex, the cost was high, and the strength of the welded joint would be weakened. At the same time, the air spring housings of conventional commercial vehicles are basically the same in specifications, so when assembling air springs with different damping force requirements, one piston housing can be used to adapt to multiple piston air tanks of different volumes, which greatly reduces the mold opening cost and improves compatibility.

[0014] The aforementioned commercial vehicle air spring with damping function can be further configured as follows: the mounting structure includes a connecting bolt and a nut passing through the piston housing and the piston air tank, one end of the connecting bolt passing through the piston air tank and the piston housing and then connected to the nut to lock the piston air tank inside the piston housing, and the damping hole is provided on the connecting bolt, with one end communicating with the air chamber and the other end communicating with the piston chamber.

[0015] By adopting the above technical solution, the piston gas tank can be conveniently installed inside the piston housing by connecting bolts and nuts. At the same time, the damping hole is set on the connecting bolt. In this way, the size of the damping hole on different piston assemblies can be easily controlled by opening damping holes of different diameters on different connecting bolts, making the adjustment of damping force simpler.

[0016] The aforementioned commercial vehicle air spring with damping function can be further configured such that: the inner wall of the piston housing is provided with multiple reinforcing ribs or slots around the piston air tank, and the end of the piston air tank away from the airbag is provided with a mounting fastener.

[0017] By adopting the above technical solutions, multiple reinforcing ribs are set on the inner wall of the piston shell, which not only does not affect the overall volume change of the piston tank, but also transmits the force to the piston tank body, thereby dispersing stress and ensuring the overall strength is reliable. Alternatively, multiple inwardly protruding slots are set, which converge to form a receiving cavity for accommodating the piston tank, limiting the piston tank laterally to prevent shaking, and transmitting the force to the piston tank body, thereby dispersing stress and ensuring the overall strength is reliable.

[0018] The aforementioned 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 disposed within the air tank shell. The inner ring wall is disposed at the center of the piston air tank and forms a first additional air chamber communicating with the damping hole. A second additional air chamber is formed between the inner ring wall and the air tank shell. An additional flow hole is provided on the inner ring wall to connect the first additional air chamber and the second additional air chamber. The first additional air chamber and the second additional air chamber constitute the piston cavity.

[0019] Using the above technical solution, the inner ring wall is used to divide the interior of the outer shell into two sets of auxiliary air chambers, and in conjunction with auxiliary flow holes, ensures that the gas flows along a stable path. When the air bladder is compressed or expanded, the gas flows between the piston chamber and the air bladder chamber through the damping holes. The design of the first and second auxiliary air chambers makes the gas flow path more complex, increases the resistance to gas flow, and thus generates a greater damping force. Furthermore, the centrally located inner ring wall also increases the overall structural strength of the piston gas tank, preventing the problem of inner wall indentation caused by prolonged gas intake and exhaust.

[0020] The aforementioned commercial vehicle air spring with damping function can be further configured such that: the bottom of the piston tank has a tank base plate, the tank base plate is welded to the inner ring wall and the tank shell, and cooperates with the tank shell to form the piston cavity, and a mounting fastener is provided through the center of the tank base plate.

[0021] Using the above technical solution, the gas tank bottom plate is connected to the inner ring wall and the gas tank shell of the piston gas tank to form the piston chamber. The mounting fastener passing through the center of the gas tank bottom plate facilitates the 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 to the inner ring wall and the gas tank shell ensures the structural integrity and sealing of the piston gas tank, preventing gas leakage, and also facilitates the installation of connecting bolts and mounting fasteners as well as the processing of additional flow holes.

[0022] The aforementioned commercial vehicle air spring with damping function can be further configured as follows: the piston housing has a connecting flange at the end facing the airbag interior, the upper end of the connecting flange has an anti-disengagement hook, the lower end of the airbag is sealed on the connecting flange, and the lower end of the airbag is connected to a steel wire ring, the connecting bolt is located inside the connecting flange, and its end position is lower than the connecting flange.

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

[0024] The aforementioned commercial vehicle air spring with damping function can be further configured as follows: the coil plate assembly includes an end plate, the end plate is provided with two sets of mounting holes, each set of mounting holes is welded with a set of air pipe connectors, the outer ring of the end plate is provided with a riveting edge that rolls towards the airbag, the upper end of the airbag is inserted into the riveting edge and the upper end of the airbag is connected to a steel wire ring.

[0025] By adopting the above technical solution, the riveting edge and the upper end of the airbag are matched to securely fix the upper end of the airbag to the end plate, and a steel wire ring is set between the airbag and the end plate to enhance the reliability of the connection between the airbag and the end plate.

[0026] The aforementioned commercial vehicle air spring with damping function can be further configured as follows: the piston housing includes a side wall, a top plate provided at one end of the side wall facing the air bladder for mounting a connecting flange, an opening provided at the bottom of the side wall for mounting a piston air tank, a side skirt that gradually extends outward at one end of the side wall with the opening, the side skirt being integrally formed with the side wall and the connecting flange, and an annular hollow groove between the side skirt and the side wall.

[0027] Using the above technical solution, the piston housing is roughly cylindrical with one end open, facilitating the installation of the piston air tank. The piston housing is constructed from sides, a top plate, and side skirts. An annular perforated groove is created between the side skirts and the sidewalls to reduce the weight of the piston assembly, achieving lightweighting while avoiding the problem of air holes caused by excessively thick sidewalls during injection molding or die casting. The side skirt design allows the air spring's bladder skin to flip up to the skirt edge during compression, increasing the effective area and correspondingly increasing the load-bearing capacity. This achieves a static elastic characteristic with a straight front and a curved rear, resulting in minimal stiffness change in the air spring during the initial compression stage, providing stable support. As compression increases, the side skirts of the piston housing begin to function, and the flipping of the air spring bladder skin leads to an increased effective area, providing a non-linear increase in load-bearing capacity in the later stages of compression. This design allows 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 aforementioned air spring for commercial vehicles with damping function can be further configured as follows: A method for optimizing the damping characteristics of an air spring for commercial vehicles with damping function includes the following steps:

[0029] S1. Obtain the load-bearing capacity, stiffness, and working stroke requirements of the suspension system based on the specific needs of the commercial vehicle;

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

[0031] S3. Based on the stiffness requirements 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 which ranges from 2 to 5.5 mm;

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

[0034] S6. Apply the suspension dynamic stiffness obtained in step S5 to the suspension natural frequency formula: The natural frequencies of the air springs under different internal pressures were 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 air springs with different damping orifice diameters under simulated working conditions on the test bench. The test environment is simulated at test speeds of 0.13m / s and 0.52m / s. The test frequency of air springs is converted. The compression damping force and the recovery damping force of air springs with different damping orifice diameters at the test speed are calculated.

[0036] S8. Using computer simulation technology, adjust the diameter of the damping orifice and the volume ratio of the air chamber to the piston chamber to optimize the damping force of the suspension system;

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

[0038] Using the above technical solution, step S1 determines the design parameters of the suspension system based on the specific needs of commercial vehicles, such as load-bearing capacity, suspension stiffness, and working stroke. Step S2 uses finite element analysis to simulate the load and displacement of the suspension system under different operating conditions to determine the optimal dimensions of the piston housing, ensuring structural reliability and efficiency. Step S3 selects a suitable piston chamber volume for the piston air tank based on the stiffness requirements of the suspension system to ensure that the stiffness of the air spring meets design requirements, thus affecting the dynamic performance of the suspension. Step S4 designs and manufactures piston bolts with damping holes of different diameters, ranging from 2-5.5mm, used to control gas flow and generate damping force, facilitating direct installation on the corresponding piston housing and piston air tank. Step S5 simulates operating conditions on an MTS test bench, according to GB / T 13061-2017 "Technical Specification for Air Springs for Commercial Vehicle Air Suspension" tests the dynamic stiffness of air springs under different internal pressures, collects data, and S6 calculates the suspension dynamic stiffness K using the dynamic stiffness conversion formula. The conclusion is that the lower the dynamic stiffness, the lower the natural frequency, and the higher the vehicle's driving comfort and smoothness. This allows for the evaluation of air spring performance under different volume ratios and damping orifice diameters in the suspension system, assessing the impact of air springs with air chambers on the vibration response of the suspension system. S7 follows the shock absorber industry standard Q... The test speeds specified in C / T491-2018 (0.13 m / s and 0.52 m / s) are used to convert the air spring test frequency. The MTS test bench is used to test the air spring damping force, measuring the compression and recovery damping forces of the air springs under different damping orifice diameters. This ensures the suspension system provides appropriate damping under various conditions. S8 uses computer simulation technology to adjust the orifice diameter and the volume ratio of the air chamber to the piston chamber, optimizing the suspension system's damping force to adapt to different driving conditions. Through data comparison, under the same operating conditions... The air spring with damping holes provides a damping effect, distributing the damping force of the shock absorber and thus reducing its size, effectively lowering the suspension's weight and cost. Simultaneously, the damping force generated by the air spring effectively reduces internal wear on the shock absorber, extending its lifespan and reducing user maintenance costs. Finite element analysis shows that increasing the piston volume within a certain range increases the damping ratio, resulting in a greater damping force. Therefore, the smaller the ratio of the air spring volume to the piston volume, the greater the damping force. The S9 was fitted with the optimized suspension system on actual vehicles for performance verification testing to ensure it met design requirements such as comfort, stability, and handling. Through a complete optimization method for the damping characteristics of commercial vehicle air springs, and by optimizing the design of the damping holes, the most convenient way to select and optimize parameters according to customer needs can be achieved, reducing the weight and cost of the suspension system, extending the shock absorber's lifespan, and thus lowering user maintenance costs. This method provides an innovative solution for the design and optimization of commercial vehicle suspension systems.

[0039] The beneficial effects of this invention are as follows:

[0040] 1. By optimizing the damping hole design, air springs 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 orifices provide a larger damping angle at different frequencies, which means that the suspension system can dampen vibrations more quickly when faced with road impacts or vibrations, improving vehicle stability and handling.

[0042] 3. By reducing reliance on the damping force of traditional shock absorbers and replacing the damping force requirements of the shock absorber indexing section, the weight of the suspension system is reduced, thereby helping to improve fuel efficiency and reduce the overall weight of the vehicle.

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

[0044] 5. The design of the damping orifice allows the air spring to easily adjust the diameter of the piston chamber and the damping orifice, meeting the damping force requirements of different specifications, improving product adaptability, and reducing additional mold opening costs.

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

[0046] The present invention will now be further described with reference to the accompanying drawings. Attached Figure Description

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

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

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

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

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

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

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

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

[0055] Figure 9 This is a damping angle curve diagram of an embodiment of the present invention with a φ5.5 damping orifice.

[0056] Figure 10 This is a volume ratio-damping ratio curve of an embodiment of the present invention. Detailed Implementation

[0057] like Figures 1-5 As shown, a commercial vehicle air spring with damping function includes an airbag 1 and a piston assembly. The airbag 1 is connected to a coil plate assembly at the top and to the piston assembly at the bottom. The coil plate assembly is connected to an air pipe connector 2, which is hollow and communicates with the airbag cavity V1 inside the airbag 1. The piston assembly has a piston cavity V2. The piston assembly has at least one damping hole 50 that connects the piston cavity V2 and the airbag cavity V1. The diameter of the damping hole 50 is 2-5.5mm, and the volume ratio of the airbag cavity V1 to the piston cavity V2 is 1-8. The piston assembly includes a piston housing 3, a piston air tank 4 installed in the piston housing 3, and a connecting bolt 5 and a nut 51 that fix the piston air tank 4 to the piston housing 3. One end of the connecting bolt 5 passes through the piston air tank 4 and the piston housing 3 and is connected to the nut 5, locking the piston air tank 4 in the piston housing 3. The damping hole 50 is located at the center of the connecting bolt 5, and one end communicates with the airbag cavity V1, while the other end communicates with the piston cavity V2.

[0058] like Figures 1-5As shown, the piston housing 3 includes a side wall 31, a top plate 32 located at the end of the side wall 31 facing the air bladder 1 for mounting a connecting flange 321, and an opening 33 located at the bottom of the side wall 31 for mounting the piston air tank 4. The side wall 31 with the opening 33 has a side skirt 311 that gradually extends outwards. The side skirt 311, the side wall 31, and the connecting flange 321 are integrally formed. An annular perforated groove 312 exists between the side skirt 11 and the side wall 31. The side skirt 11 is designed so that when the air spring is compressed, the air bladder 1's skin flips to the position of the side skirt 11, increasing the effective area and correspondingly increasing the load-bearing capacity. This achieves a static elastic characteristic with a straight front and a curved rear, resulting in minimal change in the air spring stiffness during the initial compression stage, providing stable support. As compression increases, the side skirt 11 of the piston housing 3 begins to function. The roll-up of the airbag 1's skin increases the effective area, thereby providing a non-linearly increased load-bearing capacity in the later stages of compression. This design allows 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. The inner wall of the piston housing 3 is surrounded by multiple reinforcing ribs 34 corresponding to the piston air tank 4. The end of the piston air tank 4 away from the airbag 1 is provided with a fastener 35 to facilitate subsequent assembly with the suspension system. The upper end of the connecting flange 321 is provided with an anti-disengagement hook 322. The lower end of the airbag 1 is sealed on the connecting flange 31, and the lower end of the airbag 1 is connected with a steel wire ring 30. The connecting bolt 5 is located inside the connecting flange 31, and its end position is lower than the connecting flange 31, so that when the airbag 1 retracts excessively, the skin will also be blocked by the connecting flange 31, without affecting the air intake and exhaust of the damping orifice 50.

[0059] like Figures 1-2 As shown, the piston cylinder 4 includes a cylinder shell 41 and an inner ring wall 42 disposed within the cylinder shell 41. The inner ring wall 42 is disposed at the center of the piston cylinder 4 and forms a first auxiliary air chamber V21 that communicates with the damping hole 50. The inner ring wall 42 and the cylinder shell 41 form a second auxiliary air chamber V22. An auxiliary flow hole 421 is provided on the inner ring wall 42 to connect the first auxiliary air chamber V21 and the second auxiliary air chamber V22. The first auxiliary air chamber V21 and the second auxiliary air chamber V21 form a total piston cavity V2. The bottom of the piston cylinder 4 has a cylinder base plate 43. The cylinder base plate 43 is welded to the inner ring wall 42 and the cylinder shell 41 and cooperates with the cylinder shell 41 to form the piston cavity V2. A mounting fastener 35 is inserted through the center of the cylinder base plate V2.

[0060] like Figure 1 , Figure 2As shown, the rolled plate assembly includes an end plate 6, which has two sets of mounting holes 61. Each set of mounting holes 61 is welded with a set of air pipe connectors 2. The outer ring of the end plate has a riveting edge 62 that is rolled towards the airbag 1. The upper end of the airbag 1 is inserted into the riveting edge 62 and the upper end of the airbag 1 is connected to a steel wire ring 30 to enhance the reliability of the connection between the airbag 1 and the end plate 6.

[0061] like Figures 6-9 As shown, the difference between this invention and the prior art lies in the addition of an extra piston chamber. By controlling the diameter of the damping orifice, the air spring can bear part of the damping force requirement. The impact of the additional piston chamber on the air spring stiffness is shown in the table below:

[0062]

[0063]

[0064] The table above shows that, according to GB / T 13061-2017 "Technical Specification for Air Springs for Commercial Vehicle Air Suspension", the dynamic stiffness values ​​of air springs with and without piston chambers were tested respectively. The dynamic stiffness K of the air spring under different internal pressures is shown in the table. t The formula for converting the dynamic stiffness of air springs and suspensions is K = i 2 ·K t To obtain the suspension dynamic stiffness K, where K is... t Let K be the air spring stiffness, K be the suspension stiffness, and i be the suspension lever ratio. The dynamic stiffness of the suspension K is related to the air spring stiffness Ki. t The relationship is directly proportional, 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 suspension stiffness. The test results and formula show that the stiffness of the air spring with the piston chamber on the front 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, using the MTS test bench to simulate vehicle operating conditions, the damping angle values ​​of air springs with different damping orifices and fully open piston chambers were tested at different frequencies and amplitudes. The effects of the presence or absence of damping orifices and different orifice diameters on the air spring damping angle were investigated. The damping angle reflects the degree of energy loss of the vibration system within one cycle. A larger damping angle indicates faster energy loss and amplitude decay, resulting in better system stability. A larger damping angle value indicates a better damping effect.

[0068] I. See also Figure 6 The damping angle curve and the frequency amplitude data table for the damping angle curve and the undamped orifice are as follows:

[0069]

[0070]

[0071] II. See Figure 7 The damping angle curve and the frequency amplitude data table for a damping orifice with a diameter of 2mm are as follows:

[0072]

[0073] III. See Figure 8 The damping angle curve and the frequency amplitude data table for a 4mm diameter damping orifice are as follows:

[0074]

[0075]

[0076] IV. See Figure 9 The damping angle curve and the frequency amplitude data table for a damping orifice with a diameter of 5.5 mm are as follows:

[0077]

[0078] Data analysis revealed a significant difference in damping angle between air springs with damping orifices and those with fully open air chambers. Air springs with damping orifices exhibited a larger damping angle and better damping performance (0-15Hz represents the excitation frequency range of commercial vehicle road surfaces). The maximum damping angle distribution area differed depending on the orifice size; for example... Figure 7 As shown, when the damping orifice diameter is 2mm, the damping angle of the air spring is larger when the frequency is low and the amplitude is small. However, the damping angle will be smaller when the frequency is high and the amplitude is large. This indicates that at low frequency and amplitude, i.e. when the vehicle slowly passes over small road unevenness or is subjected to small impacts, the damping orifice allows the air to flow at a relatively slow speed, and the damping angle will be relatively large. A large damping angle means faster energy dissipation and rapid vibration decay, thus providing better comfort and stability. Under high frequency and large amplitude conditions, such as when a vehicle quickly passes over large road unevenness or is subjected to large impacts, the airflow speed increases, and the flow-limiting effect of the damping orifice becomes more obvious, resulting in a smaller damping angle. A small damping angle means slower energy dissipation and slower vibration decay, which reduces ride comfort because the suspension system cannot quickly absorb and dissipate vibration energy. By analyzing the common driving conditions of the models sold and adjusting the diameter of the damping orifice, the damping characteristics of the air spring can be finely adjusted 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, using the MTS test bench to simulate vehicle operating conditions, the air spring test frequencies were converted according to the test speeds of 0.13 m / s and 0.52 m / s specified in the shock absorber industry standard QC / T491-2018. The compressive damping force and restoring damping force of the air spring at speeds of 0.13 m / s and 0.52 m / s are shown in the table below:

[0080] Test speed (m / s) Damping orifice diameter (mm) Compression damping force (N) Rebound 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] Data comparison shows that, under the same operating conditions, air springs with damping holes have a damping effect, which 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 slow down the internal wear of the shock absorber, extend the service life of the shock absorber, and thus reduce the user's maintenance costs.

[0082] For example, commercial vehicles require the following damping forces: Compression damping force: 1305±20%N at 0.13m / s; Damping force at 0.52m / s: 3860±20%N; Restoration damping force: 1532±20%N at 0.13m / s; Damping force at 0.52m / s: 4669±20%N. Without air springs with damping holes, the damping force requirement must be borne entirely by the shock absorber. This can be addressed by adjusting the existing air springs... The piston chamber controls the diameter of the damping orifice. At this time, a φ4 air spring is selected to share part of the damping force requirement. The shock absorber only needs to bear the damping force requirements of 710±20%N for 0.13m / s compression damping force and 955±20%N for recovery damping force, 2618±20%N for 0.52m / s compression damping force and 3460±20%N for recovery damping force. This can greatly reduce the size of the shock absorber, effectively reduce the weight and cost of the suspension, and achieve the requirements of lightweight and high damping.

[0083] See Figure 10 The volume ratio-damping ratio curve and the comparison table of volume ratio and damping ratio 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] Based on the influence of the ratio of different internal volumes of the piston on the damping ratio using finite element analysis, increasing the piston volume within a certain range increases the damping ratio, resulting in a greater damping force. Therefore, it is concluded that the smaller the ratio of the airbag cavity volume to the piston cavity volume, the greater the damping force. For example, if the airbag cavity volume is approximately 9.5L and the piston cavity volume is approximately 2.15L, the volume ratio is 4.419, and the damping ratio is 3.3. In this case, simply replacing the piston cylinder with one of different sizes, while keeping the airbag cavity volume constant, increases the piston cavity volume, thereby increasing the damping force and enabling convenient fine-tuning of the damping force.

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

[0087] S1. Based on the specific requirements of commercial vehicles, determine the following parameters for the suspension system: load capacity 8000kg±200kg, stiffness 10000±500N / mm, compression damping force: 1305±20%N at 0.13m / s; 3860±20%N at 0.52m / s; restoring damping force: 1532±20%N at 0.13m / s; 4669±20%N at 0.52m / s.

[0088] S2. Using finite element analysis technology, the load and displacement of the suspension system under different working conditions were simulated, and the optimal dimensions of the piston housing were determined to be a diameter of 250 mm and a height of 150 mm.

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

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

[0091] S5. Test the dynamic stiffness K of the air spring under different internal pressures on the test bench under simulated working conditions. t 200 N / mm, and data was collected, then the dynamic stiffness of the air spring and the dynamic stiffness of the suspension were converted using the formula K = i 2 ·K t To obtain the suspension dynamic stiffness K, where K is... t Where is the air spring stiffness, K is the suspension stiffness (800 N / mm), and i is the suspension lever ratio (2).

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

[0093] S7. Test the damping force of air springs with different damping orifice diameters under simulated working conditions on a test bench. The test environment simulates the test frequency conversion of air springs at test speeds of 0.13m / s and 0.52m / s. The compressive damping force of the air spring with a 4mm diameter damping orifice is:

[0094] Damping force at 0.13 m / s: 595 N; Damping force at 0.52 m / s: 1242 N; Restoring damping force: Damping force at 0.13 m / s: 577 N; Damping force at 0.52 m / s: 1209 N. It can handle most of the damping force specifications. At this time, the vibration damper only needs to handle the damping force requirements of 710±20% N for compression damping at 0.13 m / s, 955±20% N for restoring damping, 2618±20% N for compression damping at 0.52 m / s, and 3460±20% N for restoring damping.

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

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

Claims

1. A commercial vehicle air spring with damping function, comprising a gas bag, a piston assembly, the upper part of the gas bag is connected with a roll plate assembly, the lower part of the gas bag is connected with the piston assembly, the roll plate assembly is connected with a gas pipe joint, the gas pipe joint is hollow and communicates with a gas bag cavity inside the gas bag, characterized in that: The piston assembly has a piston cavity, at least one damping hole is arranged on the piston assembly to connect the piston cavity and the air bag cavity, the diameter of the damping hole is 2-5.5mm, the volume ratio of the air bag cavity to the piston cavity is 1-8, the piston assembly comprises a piston shell, a piston gas tank arranged in the piston shell and a mounting structure for fixing the piston gas tank and the piston shell, the damping hole is arranged on the corresponding end surface of the piston gas tank and the piston shell and connects the piston cavity and the air bag cavity in the piston gas tank, the mounting structure comprises a connecting bolt and a nut arranged between the piston shell and the piston gas tank, one end of the connecting bolt is connected with the nut after penetrating through the piston gas tank and the piston shell to lock the piston gas tank in the piston shell, the damping hole is arranged on the connecting bolt and connected with the air bag cavity at one end and the piston cavity at the other end, the piston gas tank comprises 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 forms a first additional air chamber connected with the damping hole, a second additional air chamber is formed between the inner ring wall and the gas tank shell, an additional flow hole is arranged on the inner ring wall to connect the first additional air chamber and the second additional air chamber, and the first additional air chamber and the second additional air chamber form the piston cavity.

2. The commercial vehicle air spring with damping function according to claim 1, characterized in that: A plurality of reinforcing ribs or clamping grooves are arranged around the inner wall of the piston shell corresponding to the piston gas tank, and the end of the piston gas tank away from the air bag is provided with a mounting fastener.

3. The commercial vehicle air spring with damping function according to claim 1, characterized in that: The bottom of the piston gas tank is provided with a gas tank bottom plate, the gas tank bottom plate is welded with the inner ring wall and the gas tank shell and cooperates with the gas tank shell to form the piston cavity, and the center of the gas tank bottom plate is provided with a mounting fastener.

4. The commercial vehicle air spring with damping function according to any one of claims 1-3, characterized in that: The end of the piston shell towards the inside of the air bag is provided with a connecting flange, the upper end of the connecting flange is provided with an anti-unhooking hook, the lower end of the air bag is sleeved on the connecting flange, and the lower end of the air bag is connected with a wire ring, the connecting bolt is arranged in the connecting flange and the end position is lower than the connecting flange.

5. The commercial vehicle air spring with damping function according to any one of claims 1-3, characterized in that: The winding plate assembly comprises an end plate, two groups of mounting holes are arranged on the end plate, a group of air pipe joints are welded at each mounting hole, the outer ring of the end plate is provided with a riveting edge facing the winding of the air bag, the upper end of the air bag is inserted into the riveting edge and connected with a wire ring.

6. The commercial vehicle air spring with damping function according to claim 4, characterized in that: The piston shell comprises a side wall, a top plate provided at one end of the side wall towards the air bag for mounting the connecting flange, an opening provided at the bottom of the side wall for mounting the piston gas tank, the side wall provided with the opening is provided with a side skirt gradually extending outward at one end, the side skirt and the side wall are integrally arranged with the connecting flange, and the side skirt and the side wall have an annular hollow groove therebetween.

7. A method for optimizing the damping characteristics of a commercial vehicle air spring having a damping function according to any one of claims 1 to 3, characterized in that The method comprises the following steps: S1. According to the specific needs of commercial vehicles, determine the carrying capacity, stiffness and working stroke requirements of the suspension system; S2. Using finite element analysis technology, simulate the carrying and displacement of the suspension system under different working conditions to determine the optimal size of the piston shell; S3. According to the stiffness requirement of the suspension system confirmed in step S1, select the corresponding piston cavity volume to ensure that the stiffness of the air spring meets the design requirements; S4. Design and manufacture piston bolts with different aperture diameters of damping holes, the aperture diameter of the damping hole ranges from 2 to 5.5 mm; S5. Test the air spring dynamic stiffness of the air spring under different internal pressure in the test bench simulation working condition and collect data, and then obtain the suspension dynamic stiffness K through the air spring dynamic stiffness and suspension dynamic stiffness conversion formula K = i2· , wherein K is the air spring stiffness, K is the suspension stiffness, and i is the suspension lever ratio. ​ S6. Perform suspension natural frequency formula operation on the suspension dynamic stiffness obtained in step S5: , obtain the natural frequency of the air spring under different internal pressure to evaluate the effect, wherein m is the spring mass of the automobile, and K is the suspension stiffness. S7. Test the damping force of the air spring under different aperture diameters of the damping hole under the test bench simulation working condition, the test environment simulates the air spring test frequency conversion under the test speed of 0.13 m / s and 0.52 m / s, the compression damping force and the recovery damping force of the air spring under different aperture diameters of the damping hole under the test speed; S8. Adjust the aperture diameter of the damping hole and the volume ratio of the air bag cavity and the piston cavity using computer simulation technology, and optimize the damping force of the suspension system; S9. Install the optimized suspension system on the actual vehicle and perform performance verification test to ensure that the design requirements are met.

Images