Analysis of current situation and development

by:FUSAI     2020-05-22
????The suspension system is composed of elastic elements, guides, shock absorbers, buffer blocks and lateral stabilizers. Generally speaking, the suspension system of automobiles is divided into two types: non-independent suspension and independent suspension. At present, the suspension of domestic heavy trucks is mainly non-independent suspension, and the elastic element of the suspension is generally a leaf spring. ● Types of domestic heavy truck suspension ????Leaf spring suspension ????Leaf spring suspensions (referred to as leaf spring suspensions) are further divided into a few-piece variable-section steel plate suspension and an equal-section multi-piece leaf spring suspension. At present, more than 95% of domestic heavy truck suspension systems are non-independent suspensions that use leaf springs as elastic elements and also serve as guiding devices. Its main advantages are simple structure, easy manufacturing, convenient maintenance, mature technology and reliable work. Analysis of current situation and development trend of domestic heavy truck suspension Schematic diagram of steel plate suspension ????The disadvantage is that the car has smoothness and poor comfort; the unsprung mass is large, and it cannot adapt to the development of light weight of heavy trucks, and it cannot take into account both the comfort and handling stability of heavy trucks. The air suspension makes full use of the rigidity of the air spring to achieve the purpose of taking into account both of these aspects. ????Air suspension ????The air suspension system uses an air spring as an elastic element and uses air as an elastic medium to fill compressed air (at a pressure of 0.5 ~) in a sealed container. The compressibility of the gas is used to achieve its elasticity. This kind of spring has variable stiffness and ideal elasticity. Analysis of current situation and development trend of domestic heavy truck suspension Schematic of air suspension ????At present, there are two main control modes for air suspension. One 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, and improves the operating comfort and response sensitivity of the suspension. ????Rubber suspension Analysis of current situation and development trend of domestic heavy truck suspension Schematic diagram of rubber suspension ????The rubber suspension uses a rubber spring as an elastic element. Because the rubber spring has the characteristics of variable stiffness, the entire suspension has a strong bearing capacity. The rubber suspension has advantages over the traditional steel plate suspension in terms of load bearing capacity and reliability, and can adapt to harsh working 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 enterprises all over the country, and there are about 80 professional production enterprises with scale (production scale of more than 8 thousand tons). The product quality level has reached the level of advanced foreign countries in the 1990s. Most enterprises are small in scale, with low concentration of production, and the problem of unbalanced distribution is more serious. ????Among them, few enterprises have truly formed large-scale and large-scale production, and most of them still remain at the level of simple production processes, and the product costs are relatively high, making it difficult to participate in international market competition. There are only four domestic enterprises that can produce high-end automotive steel plate suspension springs: FAW Group Liaoyang Automobile Spring Factory, Dongfeng Automobile Suspension Spring Co., Ltd., Chongqing Hongyan Automobile Spring Factory, Shandong Automobile Spring Factory. Leaf springs, graded stiffness springs, leaf springs with a small number of variable cross-sections, and double-curvature radius and straight section automotive leaf springs. There are only three domestic manufacturers that can simultaneously produce passenger car, truck, and car suspension springs: FAW Group Liaoyang Auto Spring Factory, Dongfeng Auto Suspension Spring Co., Ltd., and Shandong Auto Spring Factory. ????In the field of heavy trucks, each OEM basically has its own leaf spring supporting manufacturers. The FAW Jiefang heavy truck leaf spring suspension is mainly supported by the FAW Group Liaoyang Automotive Spring Factory; the Dongfeng heavy truck leaf spring suspension is mainly supported by Dongfeng automobile suspension springs Co., Ltd .; Sinotruk Leaf Spring Suspension is mainly provided by Shandong Auto Spring Factory, SAIC Iveco Hongyan Leaf Spring Suspension is mainly provided by Chongqing Hongyan Auto Spring Factory and Chongqing Hongqi Leaf Spring Factory, JAC and Hualing Heavy Truck Spring The suspension is mainly provided by Anhui Anhuang Machinery Co., Ltd. ● Air suspension ????Air suspension spring is a suspension system used in high-end 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 spring flat steel is no longer needed or used. Air suspensions have a history of more than 70 years in developed countries in Europe and America. In the 1950s, air suspension springs began to be used in trucks, cars, buses, and railway vehicles. By the 1960s, most of the buses produced by industrially developed countries such as Germany and the United States were equipped with air spring suspensions. ????At present, 95% of passenger cars, 80% of trucks and 40% of trailers in Europe and the United States have 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 number of heavy trucks and On the trailer. Although the heavy-duty truck HOWO-A7, Dongfeng Tianlong, Jiefang J6, Valin Star Kaima and other manufacturers have air suspension in the high-end products, but only at the conceptual stage, it is really accepted by the market and it will take a while to achieve mass production. time. ????This is mainly related to China's national conditions. Although domestic efforts to manage overloading and overloading have been strengthened, the phenomenon of user overloading is still relatively serious. Due to the poor overloading of the air suspension system, coupled with the high price, the fierce competition in the domestic logistics industry, and the low profit Not accepted by customers, it can only be used 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 that of the leaf spring suspension system, but according to the experience of 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, which also helps to extend the life of the car, 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 vehicle air suspension systems in the Chinese market: ????The first category is the air suspension system that entered the Chinese market as a whole with the imported models. This category is mainly reflected in the passenger car market, such as Xi'an Volvo, Changzhou Iveco, Yaxing Benz and so on. This category occupies a dominant position in China's automotive air suspension system market. ????The second type is the air suspension system directly imported from abroad. The supply cycle of this type of vehicle air suspension system is generally more than three months, it is difficult to adapt to the Chinese habit of supplying within one month, and the transportation cost is high. Its biggest disadvantage is that it does not accept water and soil in China. Such suppliers mainly include the American company Hendrickson (HENDRICKSON), the U.S. Tahaier Group Air Suspension Manufacturing Company, the US Firestone Tire Company and Goodyear Tire Company, and the German BPW Axle Company Wibach and Continental. ContiTech Air Suspension Manufacturing Company under the group. ????The third category is based on the introduction, digestion and absorption of foreign advanced vehicle air suspension system technologies, taking into account the Chinese automobile status, road conditions and transportation characteristics, and adhering to the principle of combining advancedness and reliability, based on the user's specific vehicle model. Carry out secondary development and personalized design to ensure the rationality and scientificity of structural matching, tailor-made and improve the overall performance of the chassis. Such suppliers mainly include Shanghai Keman Vehicle Parts System Co., Ltd. and Dongfeng Automobile Suspension Spring Co., Ltd., etc. Such suppliers occupy the mainstream market of domestic air suspension. ????Shanghai Keman Vehicle Parts System Co., Ltd. is a mainstream domestic air suspension supplier. The company was established in 2002 and has now become Jinlong United Automobile Industry (Suzhou) Co., Ltd., Xiamen Jinlong United Automobile Industry Co., Ltd., and Dongfeng Hangzhou Automobile Co., Ltd. , Europe V Bus, China National Heavy Duty Truck and other domestic qualified suppliers of nearly 30 well-known automobile companies. It has formed a total of 90 platforms of nearly 90 varieties of all-air suspension system products for medium-sized buses, large buses, front independent suspensions for buses, and heavy-duty trucks. At present, the market share of commercial vehicle air suspensions exceeds 20%. ????Rubber suspension ????The domestic rubber suspension is provided by the American Henderson Company, so it is also called the Henderson rubber suspension. China National Heavy Duty Truck chose the rubber suspension in the HOWO-A7 series heavy truck launched recently. Previously, companies such as FAW Jiefang and SAIC Iveco Hongyan also launched products using rubber suspensions, so the new suspension structure form of rubber suspension gradually attracted the attention of the industry. ????Henderson Corporation is a multinational company specializing in the design and manufacture of suspension systems for medium and heavy vehicles, and is the world's largest supplier of suspension systems. The company was founded in 1913 and is headquartered in Chicago, USA, with more than 3,000 employees. In addition to supplying rubber suspensions, Henderson is also a major air suspension supplier in North America, with a market share of more than 75% in the suspension of heavy trucks and trailers in the United States. ????At present, Han Ruisen mainly sells HN522 rubber suspensions in China, which is characterized by softer suspension stiffness and improved ride comfort; lighter weight, increased payload, reduced tire wear, lower maintenance costs, and resale value Higher; variable suspension stiffness, auxiliary rubber springs, horizontal and vertical stabilizer bars, etc. to improve vehicle stability and safety. In addition, Henderson also cooperates with Sinotruk to develop the RS-850 (loaded mass) heavy-duty vehicle suspension system project. Other competitors in the industry cannot match the similar heavy-duty suspension system. ● Suspension market development trend ????Electronically controlled air suspension and rubber suspension represent the current development direction of automotive suspension systems. The development of automobile suspensions in Europe and America has gone through the process of 'leaf spring → airbag composite suspension → passive all-air suspension → active all-air suspension (ie ECAS system) or rubber suspension'. In Europe and the United States, the price of rubber suspension and air suspension is not much different, but the use environment is different, the air suspension cannot be overloaded, so it is widely used in tractors. ????The rubber suspension has strong adaptability and can be used in an overloaded environment. Therefore, it is mainly used in off-highway vehicles or cars with severe working conditions and heavy vehicle load requirements. At present, the ECAS system has been applied to 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 automobile suspensions. ????Although air suspension and rubber suspension have been introduced in the field of heavy trucks in China for many years, why hasn't mass production been achieved so far? The author believes that there are mainly the following reasons: ????1. The phenomenon of overloading and overrun of domestic users is serious. For a long period of time, the operation mode of domestic heavy truck users has been to create profits by overloading and over-limiting, which has suppressed the demand for new suspensions. Since 2005, the country has stepped up efforts to control overruns and limits, and the weighted toll policy has been further implemented. Now more than 90% of highways in the country have begun to implement weighted tolls. It has been developed in the direction of light weight, comfort, and economy. At present, air suspension has been first introduced on some tractors that transport special products (such as precision instruments). ????2. The purchase and maintenance costs are relatively high, and the maintenance is not convenient. The low profitability of the domestic logistics industry has caused heavy truck users to be highly price sensitive. Although Henderson Rubber Suspension has a strong overload capacity, it is expensive and inconvenient to maintain. Therefore, users of engineering vehicles such as dump trucks and mixer trucks prefer the mature leaf spring suspension. ????3. There is still a certain gap between the process and technology. When the HOWO-A7 car was displayed, there was a Henderson rubber suspension, but the ground clearance at the bottom of the suspension was only 200mm. This defect is almost fatal for engineering vehicles used in construction sites and mining areas. of. Due to the large number of rubber suspension castings and the complicated structure, the current domestic rubber suspension is still only at 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 China's heavy truck suspensions, mainly due to the following two reasons: ????First, the need for the development of the heavy truck industry. With the development of China's high-grade highways, the increase in traffic, the popularization of weighted toll policies and the increase in the income of heavy truck users, they have begun to put forward higher requirements for the handling stability, smoothness, comfort and safety of cars Therefore, new suspensions that meet the above requirements are beginning to attract more and more users' attention; ????Second, policy encouragement. Because air suspension and rubber suspension have the characteristics of light weight and low degree of damage to the road, the 'Road Vehicle Outer Dimensions, Axle Loads and Quality Limits' (GB1589-2004) issued by the state The axle load quality limit of the vehicle frame or rubber suspension is 15% higher than the vehicle axle load quality of the leaf spring suspension. Therefore, at the policy level, the country has 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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