The air suspension system adjusts the height of the body and the stiffness of the suspension system by adjusting the internal air pressure of the air spring, so as to better adapt to the road conditions and driving conditions, and improve the comfort and handling of the vehicle. Compared with fuel vehicles of the same level and size, the weight of electric vehicles is heavy, the center of mass is biased, and the initial power torque is large, which puts forward higher requirements for the vehicle suspension.
In addition, for new energy vehicles, the weight of the power battery leads to an increase in the sprung mass of the car, and the air suspension is more suitable for reducing road impact, and at the same time, the air suspension can also achieve better battery cooling by optimizing the airflow under the car body. With the gradual improvement of the intelligent level of the vehicle, the stronger perception ability of the vehicle is combined with the suspension innovation, which can predict the road conditions in advance and make active adjustments, so that the vehicle has better comfort and handling at the same time.
The structure of the air suspension system is complex, mainly including air springs, air supply units (air compressors, air storage tanks, distribution valves, etc.), ECU controllers, sensors (vehicle height sensors, acceleration sensors, etc.), etc., and air springs are generally used with variable damping shock absorbers. Among them, the components with the highest value and the highest technical barriers are air compressors and air springs. In this issue, we will take you to learn about air springs.
One
Introduction to the key component of the gas spring
The air spring is an elastic element that uses the reaction force compressed inside the rubber airbag as the elastic recovery force, and is the core component of the automobile air suspension. The front air spring is combined with the shock absorber, and the rear air spring is usually arranged separately from the shock absorber.
The gas spring acts as a rubber airbag filled with compressed air.
1.The height of the vehicle can be adjusted by controlling the amount of inflation. By inflating the airbag, the ground clearance is increased, the body is raised, and the passability of the vehicle is improved;
2.By deflating the airbag, the body is lowered, the stability of high-speed driving is improved, the drag coefficient of the vehicle is reduced, and the driving economy is improved;
3.Through the single axle or the reduction of the height of the whole vehicle, it is convenient to load and unload goods and facilitate the functions of drivers and passengers getting on and off the car.
Compared with traditional coil springs, air springs have the following characteristics:
1.Compared with the linear stiffness of traditional coil springs, air springs have nonlinear stiffness characteristics, and their stiffness characteristic curves can be designed according to the needs of the whole vehicle. For example, the air spring can have a lower stiffness value when the vehicle is near the standard height, so that the air suspension can obtain a lower natural frequency to improve the driving comfort of the vehicle when driving smoothly; Different initial stiffness can be matched when the load changes (unloaded and fully loaded) to ensure driving comfort at all times. In the process of wheel jumping and air spring compression, the air spring stiffness is increased, the impact of the road surface transmitted to the body through the wheel is suppressed, and the buffer block is prevented from being broken down, so as to further improve the ride comfort and handling stability.
2.Gas springs are a great improvement over conventional steel springs in terms of isolating high-frequency vibrations and noise. In the process of vibration, the rubber skin bag has little internal friction due to telescopic and warped, so it is difficult to transmit high-frequency vibration; Air and rubber absorb vibrations and therefore have excellent sound insulation.
II
Technical barriers to gas springs
First, let's take a look at the rubber airbags. As the core component of the air spring, the rubber airbag is made of vulcanized inner rubber layer, outer rubber layer, cord layer and steel traveler. Each of these layers has its own unique function and function.
on the Internet.
First of all, the inner and outer cladding, which is divided into the inner rubber layer and the outer rubber layer, is an important part of the air spring rubber airbag wall. These layers are made of precious elastomeric materials with excellent kinetic properties and are able to withstand temperature, climatic erosion and oil stains within certain limits. In particular, the inner cladding is usually made of rubber material with excellent airtightness and oil resistance due to the need for a sealing effect.
Secondly, the cord layer is the main part that supports the load of the gas spring. The material of the cord plays a decisive role in the durability and pressure resistance of the gas spring. Typically, the cord layer consists of two layers of supports arranged in an alternating pattern. These cords have excellent bending resistance and excellent burst resistance and strength through optimized design angles.
Finally, the traveler is vulcanized within the two flange openings of the gas spring capsule. The flange structure allows it to be mounted like a tubeless tire on fixed parts such as plungers and plates, or re-tensioned to these parts with the help of hems and bolts to ensure no air leakage. Depending on the type of gas spring, the traveler can be permanently fixed to a conical seal or to a specially shaped fixture.
The perfect combination of these elements makes rubber airbags play an important role in air springs, providing a smooth and comfortable ride for the vehicle.
The core barrier of air springs is the design and craftsmanship of the capsule. As a rubber part, the durability of the capsule determines the service life of the gas spring.
The repeated lifting of the air spring, the change of the high and low temperature environment in which the vehicle is located, all pose a great challenge to the durability of the capsule, and the raw rubber and cord materials, rubber formulation, mixing, calendering, molding, vulcanization, assembly technology and other technologies will affect the service life of the air suspension.
The design of the capsule requires a large number of sample accumulation and experimental certification, and a large number of permutations and combinations need to be done in multiple links such as rubber parts formula development and vulcanization process, and then the final plan can be determined through a large number of fatigue test verification.
In addition, in the assembly process of air springs, crimping is also a great difficulty.
Therefore, the durability, tightness, and noise control of the capsule are the key points, especially for luxury brands.
Since passive air springs have been used in commercial vehicles as early as the fifties and sixties of the 20th century, most of the overseas air spring manufacturers have deep accumulation of rubber product manufacturing technology and occupy most of the market share.
Domestic rubber technology started earlier, and has been realized in the research and development, manufacturing and experimental verification of air springs. However, there is still room for improvement in durability and reliability.
III
The development trend of gas springs
3.1 Single-chamber gas spring
The most mainstream single-chamber (air chamber) air spring on the market at present. Single-chamber air spring has only one air chamber, due to its structure, simple process, low cost, is widely used by air suspension vehicles, most of the domestic passenger car air suspension models are single-chamber air springs. The single-cavity air spring can be raised or lowered when the body is charged and deflated under static load, but the internal force area of the spring does not change much when charging and deflating, so the charging and deflation will not cause a wide range of changes in stiffness. There is a difference in the structure of the front and rear air springs on the actual car.
The front (single-chamber) air spring strut assembly is mainly composed of the upper top seat assembly, the crimping ring, the airbag, the aluminum casing, the dust cover, the piston, the buffer block, the sealing cover, the shock absorber and other components, in which the front air spring and the shock absorber are combined.
Front air spring slide assembly**Fig.**Kong Hui Technology
The rear (single-chamber) air spring assembly is mainly composed of bearing seats, upper seats, pistons, crimping rings, aluminum casings, lower seats, air bags, dust covers and other components, among which the rear air springs and shock absorbers are usually arranged separately, and a few models adopt the form of rear air spring slide assembly.
Rear air spring assembly**Figure**Konghui Technology
In view of the limited adjustable range of single-chamber air spring stiffness, double-chamber, three-chamber or even more chamber gas springs have emerged, and dual-chamber and multi-chamber air springs can make the stiffness adjustable range even greater, providing a richer driving experience, and flexibly switching between comfort and sport.
3.2 Double-chamber gas springs
The double-chamber air spring separates the air chamber of the single chamber into two air chambers with a solenoid valve, compared with the single-chamber air spring, the double-chamber air spring has better performance, and the double-chamber air spring is provided with two working chambers, the main and auxiliary chambers, so there are two working modes of small chamber (only the main chamber works) and large chamber (the main and auxiliary chambers work at the same time).
The small chamber mode makes the suspension more "hard", and the large chamber mode makes the suspension more "soft", which can help the vehicle to have both sports and comfort styles, adjust the stiffness during the use of the vehicle, and switch styles as needed.
Because the structure is more complex than that of a single cavity and requires additional components such as actuators, the cost of a double-cavity multi-chamber air spring is higher.
At present, the models equipped with dual-chamber air springs in the production models are: the second-generation Porsche Cayenne, the 2020 BMW X5 (optional), the 2022 Porsche Macan series, the Zeekr 009, the NIO ES8, the Xpeng G9, etc. For example, the hyper-threaded intelligent chassis of Xpeng G9 is composed of whole vehicle vision, chassis perception, domain control and chassis domain control, and intelligent dual-chamber air suspension, which can carry out 1000 road scans and 200 suspension adjustments per second, and provide 7 driving modes.
3.3 Three-chamber gas springs
The three-chamber gas spring has three chambers and two solenoid valves inside to achieve four levels of stiffness. The three-chamber gas spring divides the air chamber of a single chamber into three air chambers, and obtains more air chambers of different volumes, which are more complex in structure and higher in cost, but have superior comprehensive performance.
There aren't many passenger cars on the market today that use three-chamber gas springs, with the 2018 Porsche Cayenne and the 2018 Mercedes-Benz GLC.
2018 Porsche Cayenne Front Air Spring Assembly **Kong Hui Technology
Fourth
Introduction to the market pattern and key enterprises of gas springs
In the air spring product market, overseas companies include Continental AG (Continental), Vibracoustic (Germany) and Firestone (Firestone) Company of the United States, and local ** companies Kong Hui Technology and Baolong Technology have achieved large-scale mass production.
According to Gaogong Intelligent Automobile, the market share of Vibrator, Konghui Technology, and Baolong in the domestic passenger car air spring system market in 2022 is %, and from January to May 2023, respectively. As the local first-class merchants gradually occupy a dominant position in the new forces and independent brand first-class systems, and at the same time, downstream models such as Ideal continue to sell well, the share of local first-class manufacturers in the air spring market has increased significantly.
The key enterprises are as follows:
(1) Abroad
Air suspension system The air spring system was originally dominated by overseas companies such as Continental and Vibrator.
Continental:In the early days, passenger car air suspension was used in Audi A8, Audi Q7, Volkswagen Touareg and other models, and the product types include air suspension systems, air springs, air supply systems, air tanks, etc. In terms of production capacity, Continental has production bases for air suspension related products in Hamburg (Germany), Nyiregyhaza (Hungary), Timisoara (Romania), and Changshu (China), as well as a rubber compound plant in Nyiregyhaza, Hungary. Among them, the first phase of the Changshu plant has been put into operation in 2021, producing air suspension modules and air supply systems, with an annual production capacity of 200,000 sets; The second phase is scheduled to be put into use in 2024 and will add an annual output of 600,000 air springs and 100,000 air supply systems.
Wieback:A subsidiary of the Freudenberg Group, it has a leading market share in the global air spring market for passenger cars, and has certain advantages in core technologies such as spring skin materials, and can provide ZAX bellows, axial bellows, transverse bellows and other technologies at the same time. With the mass production of its own air spring system ECU and air spring system in 2020-2021, the products have fully covered air suspension systems, air springs, sensors, valves, compressors, gas tanks, ECUs, software, etc. Production sites are located in Hamburg in Germany, Sroda Salska in Poland, and Wuxi and Yantai in China.
Firestone:Beijing Firestone Air Spring*** is a wholly-owned subsidiary of Firestone Industrial Products Co., Ltd. in Beijing Economic and Technological Development Zone, which produces world-class air springs. Founded in November 2004, Beijing Firestone mainly produces and sells membrane, self-closing, sleeve and capsule gas springs, providing spare parts products and technical support for automobile manufacturers. At present, Beijing Firestone's air springs have been used by more than 50 bus and truck OEMs and chassis factories in China. Good business performance and high brand awareness. In order to better meet the needs of users, Firestone USA headquarters has increased its investment in China, setting up a branch in Tianjin to expand the scale of production.
(2) Domestic
The split-fixed-point model promotes domestic substitution, and local enterprises have entered a stage of rapid development. After 2019, as more new car companies adopt air suspension configurations and seek localized alternatives, the system assembly is split into small components of air supply units, air springs, shock absorbers, and sensors to different manufacturers, providing opportunities for local manufacturers. In 2019, Konghui Technology launched the Dongfeng Lantu project, in 2020, the company harvested the first fixed-point of air springs for passenger cars, and in 2021, the company and Konghui Technology realized the mass production of air suspension products. Tuopu Group will develop an air suspension system project in 2021 and achieve mass production in 2023.
Baolong Technology:Founded in 1997, Shanghai Baolong Automotive Technology Co., Ltd. is an auto parts company integrating production, sales, product development and project investment. Headquartered in Songjiang, Shanghai, the company currently has three types of auto parts products, including automotive wheel parts, automotive exhaust system pipe fittings, and automotive electronic products. The company is one of the world's largest manufacturers of automotive tubeless valves and automotive exhaust system pipe fittings, and is the leading supplier of Ford, General Motors, Volkswagen, PSA Peugeot Citroen, Dongfeng Nissan, SAIC, and other well-known automobile manufacturers at home and abroad.
Kong Hui Technology:Zhejiang Konghui Automobile Technology Co., Ltd. (hereinafter referred to as "Konghui Technology") is located in Huzhou City, Zhejiang Province. Konghui Technology is mainly engaged in the development, integration, matching and sales of automotive electronic control suspension systems, the development, production and sales of automotive electronic control suspension related parts and automotive chassis systems; technical consulting and technical services for automotive chassis systems, development and sales of automotive dynamics software; Development and sales of automotive product testing and testing equipment. At present, the company has 15 invention patents, 4 appearance patents and 9 utility models. In 2020 and 2021, the company received investment funds from Lenovo Star and Xiaomi.
Tuopu Group:Ningbo Tuopu Group Co., Ltd. is a technology-based and platform-based auto parts enterprise listed on the Shanghai Stock Exchange, mainly committed to the research and development and manufacturing of automotive power chassis systems, trim systems, intelligent driving systems and other fields. Tuopu Group has four business divisions: power chassis system, trim system, Yuxiang Zhixing and electric drive, mainly producing shock absorption system, interior and exterior decoration system, body lightweight, chassis system, intelligent cockpit components, thermal management system, air suspension system, intelligent driving system and actuator and other products. The Group has always adhered to R&D and innovation, and has R&D centers and leading-equipment test centers that support global projects. With leading R&D technology, manufacturing technology, quality management and global capabilities, Tuopu Group has established good cooperative relations with many domestic and foreign automobile manufacturers, and has become a global partner of Audi, BMW, Stellantis, General Motors, Geely, Ford, Mercedes-Benz, Volkswagen, Gaohe, Li Li, NIO, Xpeng, Rivian, Lucid and other automobile manufacturers. Reference article:
1] Air suspension from 1 to N, local ** manufacturers continue to benefit ATC car chassis 2024-01-13
2] The latest analysis of the air suspension industry chain at home and abroad, local manufacturers welcome development opportunities, and the frontline of the automotive industry is observed2023-08-10
3] Kopu |Air Spring Peter ATC Car Chassis 2023-08-20
4] Is a gas spring really a "leather ball"? Peter ATC car chassis 2023-12-12
Finishing of automotive materials network.
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