The suspension system consists of elastic elements, guides, shock absorbers, bumpers, and stabilizers. In general, the car's suspension system is divided into two independent suspension and independent suspension. At present , the suspension of domestic heavy trucks is mainly non-independent suspension. The elastic components of the suspension are generally leaf springs.
Leaf spring suspension
The leaf spring suspension (referred to as the leaf spring suspension) is divided into a small variable-section steel plate suspension and a multi-section leaf spring suspension. At present, more than 95% of China's heavy-duty suspension systems use leaf springs as elastic components and serve as guides for non-independent suspensions. Its main advantages are simple structure, easy manufacturing, convenient maintenance, mature technology, and reliable work. The disadvantages are poor vehicle comfort and comfort; the unsprung mass is too large to accommodate the development of heavy-duty lightweight trucks, and it is not possible to balance both the comfort and handling stability of heavy-duty trucks. The air suspension makes full use of the characteristics of the air spring to become rigid, so as to achieve both of these aspects.
Air suspension
The air suspension system uses air springs as elastic components, air as elastic medium, and compressed air (pressure of 0.5~) in a sealed container, which uses the compressibility of the gas to achieve its elasticity. This kind of spring has a variable stiffness and ideal elastic properties.
At present, there are two main air suspension control modes, one of which is manual adjustment using a mechanical height valve. The other is Electronic Control (ECAS), which greatly improves the performance of the traditional air suspension system, improving the comfort and responsiveness of the suspension.
Rubber suspension
The rubber suspension is a rubber spring as an elastic member. Since the rubber spring has a characteristic of variable rigidity, the entire suspension has a strong carrying capacity. The rubber suspension has advantages over the traditionally used steel plate suspension in terms of bearing performance, reliability, and the like, and can adapt to adverse conditions such as mine operations.
Development status of domestic heavy truck suspension
Leaf spring suspension
There are more than 160 domestic automobile suspension spring production companies, which are located throughout the country. There are more than 80 professional production companies (with a production scale of over 0.8 million tons). The level of product quality has reached the level of the 1990s of foreign advanced countries. Most of the companies are small in scale, low in production concentration, and the problem of scattered and scattered problems is more serious. There are only a few companies that have truly formed large-scale, high-volume production. Most of them still remain at the level of simple production processes. The higher product costs make it difficult to participate in international market competition. There are only four domestic companies capable of producing high-end automotive steel suspension springs: FAW Group Liaoyang Automobile Spring Factory, Dongfeng Automobile Suspension Spring Co., Ltd., Chongqing Hongyan Automobile Spring Factory, and Shandong Automobile Spring Factory. They all have a variety of stacks. Leaf springs, gradient springs, small pieces of leaf springs with variable cross-sections, and the ability to double the radius of curvature and straight sections of automotive leaf springs. There are only three manufacturers that can produce suspension springs for passenger cars, trucks and cars at the same time: FAW Group Liaoyang Automobile Spring Factory, Dongfeng Automobile Suspension Spring Co., Ltd., and Shandong Automobile Spring Factory.
In the field of heavy trucks, each mainframe plant basically has its own leaf spring supporting manufacturers. The one-plate spring suspension of FAW Jiefang heavy truck is mainly supported by FAW Group Liaoyang Automobile Spring Factory; Dongfeng heavy truck leaf spring suspension is mainly composed of Dongfeng automobile suspension springs. Co., Ltd. supporting; China Sinotruk leaf spring suspension is mainly supported by Shandong Automobile Spring Factory, SAIC Iveco Hongyan leaf spring suspension is mainly supported by Chongqing Hongyan Automobile Spring Factory and Chongqing Hongqi Leaf Spring Factory, Jianghuai and Hualing heavy-duty leaf springs. Suspension is mainly supported by Anhui Anju Machinery Co., Ltd.
Air suspension
The air suspension spring is a kind of suspension system used on high-grade passenger cars and heavy-duty trucks. It is the development trend of leaf springs in the world. The final development trend of air suspension springs is that no more or less spring flat steel is needed. Air suspension has been developed in Europe and America for more than 70 years. In the 1950s, air suspension springs began to be applied to trucks, cars, buses, and railway vehicles. In the 1960s, air spring suspensions were installed in most buses produced in industrialized countries such as Germany and the United States.
At present, 95% of passenger cars, 80% of trucks and 40% of trailers in Europe and the United States have already used air suspension systems. While China is still in its infancy, air suspension systems are only used in some luxury passenger cars and a small part of heavy goods vehicles. On the trailer. Although heavy-duty trucks such as HOWO-A7, Dongfeng Tianlong, Jiefang J6, and Valin, etc. all have air suspensions in their new products listed on the market, they are only conceptual stages and they are truly accepted by the market. time. This is mainly related to China's national conditions. Although domestic governance overload exceeds limits, the user overloading phenomenon is still serious. The air suspension system is not good due to overload, coupled with high prices, fierce competition in the domestic logistics industry, and low profit margins. Not accepted by customers, it can only be applied in the transportation of special goods such as precision instruments and electronic equipment.
In fact, the initial cost of the air suspension system is higher than the leaf spring suspension system, but according to experience in use around the world, the total service life of the air spring is longer, generally about 10 times longer than the leaf spring suspension system, maintenance work Less, this also helps to prolong the life of the vehicle, so the operating cost is lower than the leaf spring suspension system, and the higher initial investment can be recovered during the operation.
At present, there are three main types of automotive air suspension systems on the Chinese market:
The first category is air suspension systems that have entered the Chinese market as a whole. This category is mainly reflected in the passenger car market, such as Xi'an Volvo, Changzhou Iveco, Yaxing Mercedes-Benz and so on. This category dominates the Chinese automotive air suspension system market.
The second category is air suspension systems imported directly from abroad. This type of vehicle air suspension system has a delivery period of more than three months, and it is difficult to adapt to the Chinese people's habit of supplying goods within one month, and the transportation cost is high. Its biggest drawback is that it does not accept water and soil in China. Such suppliers mainly include the United States Henderson (HENDRICKSON) Company, the United States, the Air Suspension Production Company of the Tahaer Group, the American Firestone Tire Company and the Goodyear Tire Company, and the German company BPW Axle Company Weibake Company and the Mainland. Group's ContiTech air suspension manufacturing company.
The third category is based on the introduction, digestion and absorption of foreign advanced air suspension systems for vehicles, taking into account the conditions of China’s automobiles, road conditions and transportation characteristics, and adhering to the principle of combining advancedness and reliability, based on the specific models of users. To carry out secondary development and personalized design to ensure the rationality and scientific matching of the structure, tailoring and improving the overall performance of the chassis. Such suppliers mainly include Shanghai Keman Vehicle Component Systems Co., Ltd., Dongfeng Automobile Suspension Spring Co., Ltd., and these suppliers occupy the mainstream market of domestic air suspension.
Shanghai Keman Vehicle Component Systems Co., Ltd. is the mainstream air suspension supplier in China. The company was established in 2002 and has now become Jinlong United Automotive Industry (Suzhou) Co., Ltd., Xiamen Jinlong United Automotive Industry Co., Ltd., and Dongfeng Hangzhou Automobile Co., Ltd. , European V passenger cars, China National Heavy Duty Truck and other domestic domestic and nearly 30 well-known automotive companies qualified suppliers. The company has formed nearly 90 varieties of all-air suspension systems for eight platforms including medium-sized passenger cars, large passenger buses, independent front passenger cars, and heavy-duty trucks. Currently, the market share of commercial air suspensions exceeds 20%. [next]
Rubber suspension
The domestic rubber suspension is provided by the Hudson Company of the United States, so it is also called the Hudson Rubber Suspension. China National Heavy Duty Truck chose the rubber suspension in the HOWO-A7 series heavy truck recently launched. Previously, FAW Jiefang, SAIC Iveco Hongyan and other companies have also introduced products using rubber suspension, so the new type of suspension suspension structure of rubber suspension gradually attracted the attention of the industry.
Hudson Corporation is a multinational company specializing in the design and manufacture of suspension systems for medium and heavy vehicles. It is the world's largest supplier of suspension systems. Founded in 1913, the company is headquartered in Chicago, the United States and employs more than 3,000 people. In addition to supplying rubber suspensions, Hudson is also the leading supplier of air suspension in North America, with more than 75% of the suspension market for heavy trucks and trailers in the United States.
At present, Han Ruisen mainly sells the HN522 rubber suspension in China. Its characteristic is that the suspension stiffness is softer and improves the smoothness of the vehicle. Since the light weight, the payload is increased, the tire wear is reduced, and the maintenance cost is reduced. Higher; variable suspension stiffness, auxiliary rubber springs, transverse, longitudinal stabilizers, etc., improve vehicle stability and safety. In addition, Hudson also cooperated with Sinotruk to develop the RS-850 heavy-duty vehicle suspension system project. Other competitors in the industry cannot match similar heavy-duty suspension systems.
Suspension Market Development Trend
Electronically controlled air suspensions and rubber suspensions represent the current development direction of automotive suspension systems. The development of automobile suspension in Europe and America has experienced the process of “leaf springs → airbag composite suspension → passive full air suspension → active full air suspension (ie ECAS system) or rubber suspensionâ€. In Europe and the United States, the price of rubber suspension and air suspension is not much different, but the use of different environments, the air suspension can not overload, so widely used in tractors; rubber suspension adaptability, can be used for overloaded environment, so the main application In off-highway vehicles or vehicles with poor working conditions and heavy vehicle loads. At present, the ECAS system has begun to be applied on some European buses. It is expected that with the development of vehicle control technology, the ECAS air suspension system will become a development direction of the vehicle suspension.
Although the air suspension and rubber suspension have been introduced in China's heavy truck field for many years, why hasn't mass production been achieved yet? The author believes there are mainly the following reasons:
1. There is a serious problem of overloading of domestic users. For quite a long period of time, the operating mode of domestic heavy-duty truck users is to create profits through overloading and limit the demand for new suspensions. Since 2005, the state has stepped up its efforts to control over-control, the toll-by-weight policy has been further implemented, and weight-based tolls have now been applied to more than 90% of highways across the country. Therefore, for road vehicles (eg, tractors), It has been developed in the direction of lightweight, comfort, and economy. At present, air suspensions have taken the lead in the introduction of certain tractors that transport special products (such as precision instruments).
2. Higher purchase and maintenance costs, inconvenient maintenance. The low profits of the domestic logistics industry have led to heavy price sensitivity among heavy truck users. Although the Hudson Rubber Suspension has strong overload capacity, it is expensive and inconvenient to maintain. Therefore, construction trucks such as dump trucks and mixer trucks prefer matured leaf spring suspensions.
3. There is still a certain gap between process and technology. When heavy-duty trucks displayed the HOWO-A7, one of them was the Hudson Rubber Suspension, but the ground clearance at the bottom of the suspension was only 200mm. This defect is almost fatal for the engineering vehicles used in construction sites and mining areas. of. Due to the large number of rubber suspension castings and complex structures, rubber suspensions in China currently only stay in the conceptual stage.
Although the introduction of new domestic suspensions is slow, in terms of heavy truck technology development, air spring suspensions and rubber suspensions represent the future development direction of our country's heavy truck suspensions. The main reasons are as follows:
First, the need for heavy truck industry development. With the development of high-grade highways in China, the increase of transportation volume, the popularization of weight-based charging policies, and the increase in the income of heavy-duty users, they have begun to impose higher requirements on the stability, smoothness, comfort and safety of automobiles. Therefore, new suspensions that meet the above requirements have begun to attract more and more users;
Second, policy encouragement. As the air suspension and the rubber suspension have the characteristics of light weight and low degree of damage to the road, the “Outline Size, Axial Load and Quality Limits of Road Vehicles†issued by the State (GB1589-2004) has air suspensions. The axle load quality limits of racks or rubber suspensions are 15% higher than the axle load of the loaded leaf spring suspension. Therefore, at the policy level, the country also tilted the new suspension.
In the next 5 to 10 years, with the development of the domestic automobile industry and the improvement of heavy truck technology, air suspension and rubber suspension will surely usher in a period of rapid development.
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