​operating weight Operating weight is one of the three important parameters of an excavator (engine power, bucket capacity, operating weight). The operating weight determines the level of the excavator and determines the upper limit of the excavator's digging force. Digging force≦m. working weight m: Coefficient of adhesion between the ground and the track. If the digging force exceeds this limit, in the case of a backhoe, the excavator will slip and be pulled forward, which is very dangerous. In a shovel situation, the excavator will skid backwards. Digging force For the digging force, the digging force is mainly divided into the arm digging force and the bucket digging force. The action points of the two digging forces are both the tooth roots of the bucket (the lip of the bucket), but the power is different. The forearm digging force comes from the forearm cylinder; the bucket digging force comes from the bucket oil cylinder. ground pressure The size of the ground specific pressure determines the ground conditions for the excavator to work. Ground pressure refers to the pressure exerted by the weight of the machine on the ground, expressed by the following formula: Ground specific pressure = working weight ÷ total area in contact with the ground Track shoe ·It is important to install the proper track shoes on the machine. For crawler excavators, the criteria for selecting tracks is to use the narrowest track shoes whenever possible. ·Common track type: toothed track shoes. Walking speed For crawler excavators, the walking time accounts for about one tenth of the entire working time. Generally speaking, two speeds can meet the walking performance of the excavator. traction Traction force refers to the force generated by the excavator when it travels, which mainly depends on the travel motor of the excavator. These two walking performance parameters indicate the mobility of the excavator and its walking ability. It can be reflected in the samples of various manufacturers. Gradeability Gradeability is the ability to climb, descend, or stop on a firm, level slope. Two representation methods: angle, percentage improving capability Lift capacity refers to the lesser of the rated stable lift capacity or the rated hydraulic lift capacity. Rated stable lift capacity: 75% of tipping load Rated hydraulic lift capacity: 87% hydraulic lift capacity Swing speed The slewing speed refers to the average maximum speed that the excavator can achieve during stable slewing when the excavator is unloaded. This means that the defined slew speed is neither the slew speed at start-up nor the slew speed during braking; that is, not the slew speed for acceleration or deceleration. For general excavation work, when the excavator works in the range of 0° to 180°, the slewing motor accelerates or decelerates, and when it turns to the range of 270° to 360°, the slewing speed becomes stable. Therefore, in actual excavation work, the rotation speed defined above is unrealistic. That is, the required actual swing performance is acceleration/deceleration expressed in terms of swing torque. engine power Gross horsepower refers to the power output measured at the engine flywheel without power-consuming accessories such as mufflers, fans, alternators and air filters. Net horsepower refers to the output power measured at the flywheel of the engine with all power-consuming accessories such as mufflers, fans, alternators and air cleaners installed. Determination of noise The main source of excavator noise comes from the engine. Two kinds of noise: noise measurement at the operator's ears, noise measurement around the machine.

1. Walking power transmission route: diesel engine - coupling - hydraulic pump (mechanical energy is converted into hydraulic energy) - distribution valve - central rotary joint - walking motor (hydraulic energy is converted into mechanical energy) - reduction box - driving wheel ——Rail chain crawler——to realize walking 2. Slewing motion transmission route: diesel engine - coupling - hydraulic pump (mechanical energy is converted into hydraulic energy) - distribution valve - slewing motor (hydraulic energy is converted into mechanical energy) - reduction box - slewing bearing - realize rotation 3. Boom movement transmission route: diesel engine - coupling - hydraulic pump (mechanical energy is converted into hydraulic energy) - distribution valve - boom cylinder (hydraulic energy is converted into mechanical energy) - realization of boom movement 4. Stick movement transmission route: diesel engine—coupling—hydraulic pump (mechanical energy is converted into hydraulic energy)—distribution valve—stick cylinder (hydraulic energy is converted into mechanical energy)—the stick movement is realized 5. Bucket movement transmission route: diesel engine - coupling - hydraulic pump (mechanical energy is converted into hydraulic energy) - distribution valve - bucket cylinder (hydraulic energy is converted into mechanical energy) - bucket movement is realized

At first, the excavator was manual, and it has been more than 130 years since its invention to 2013. During this period, it has experienced a whole process from steam-driven bucket rotary excavator to electric drive and internal combustion engine-driven rotary excavator, applying electromechanical-hydraulic integration technology. The gradual development process of automatic hydraulic excavators. The first hydraulic excavator was invented in Poclain, France. Due to the application of hydraulic technology, there were ground-mounted excavators equipped with hydraulic backhoes on tractors in the 1940s. In 1951, the first fully hydraulic backhoe was launched by the Poclain factory in France, thus creating a new space in the field of technical development of excavators. Azimuth hydraulic excavators and crawler full hydraulic excavators. The initial trial-produced hydraulic excavator adopts the hydraulic technology of aircraft and machine tools, lacks hydraulic components suitable for various working conditions of the excavator, the manufacturing quality is not stable enough, and the supporting parts are not complete. Since the 1960s, hydraulic excavators have entered a stage of promotion and vigorous development. The number of excavator manufacturers and varieties in various countries has increased rapidly, and the output has soared. From 1968 to 1970, the output of hydraulic excavators accounted for 83% of the total output of excavators, which was close to 100%. The first generation of excavators: the emergence of electric motors and internal combustion engines made excavators have advanced and suitable electric devices, so various excavator products were born one after another. In 1899, the first electric excavator appeared. After the First World War, diesel engines were also used in excavators. This diesel engine (or electric motor) driven mechanical excavator was the first generation of excavators. The second generation of excavators: With the extensive use of hydraulic technology, the excavator has a more scientific and applicable transmission device, and hydraulic transmission instead of mechanical transmission is a big leap in excavator technology. In 1950 Germany's first hydraulic excavator was born. Hydraulic mechanical transmission is the second generation of excavators. The third generation of excavators: The wide application of electronic technology, especially computer technology, enables the excavator to have an automated control system, and also makes the excavator develop in the direction of high performance, automation and intelligence. The germination of mechatronics occurred around 1965, and the adoption of mechatronics technology on mass-produced hydraulic excavators was around 1985, when the main purpose was to save energy. Excavator electronics are the hallmark of the third generation of excavators. Excavator industry manufacturers can be roughly divided into four categories. More than 70% of the domestic excavators are occupied by foreign brands, and the domestic brands are still mainly small excavators and medium excavators, but the share of domestic excavators is gradually increasing, with a year-on-year increase of 3.6% in 2012.

The production of excavators in China started relatively late. Since Fushun Excavator Factory produced the first mechanical single-bucket excavator with a bucket capacity of 1 m³ (cubic meter) in 1954, it has generally experienced surveying and mapping imitation, independent research and development, and development improvement. Wait for three stages. In the early days of the founding of the People's Republic of China, China's excavator production history began with surveying and mapping of mechanical single-bucket excavators such as W501, W502, W1001, and W1002 of the former Soviet Union in the 1930s and 1940s. Due to the needs of national economic construction at that time, more than ten excavator production plants have been established successively. Since 1967, China has independently developed hydraulic excavators. The products successfully developed in the early stage mainly include WY100 of Shanghai Construction Machinery Factory, W4-60 of Guiyang Mining Machinery Factory, and WY60 excavator of Hefei Mining Machinery Factory. Then appeared WYl60 of Changjiang Excavator Factory and WY250 of Hangzhou Heavy Machinery Factory. They have taken an extremely important step for the formation and development of China's hydraulic excavator industry. By the end of the 1980s, there were more than 30 excavator factories in China, producing more than 40 models. A series of medium and small hydraulic excavators have been formed, with bucket capacities ranging from 0.1 to 2.5 cubic meters in 12 grades and more than 20 models. We also produce 0.5-4.0 cubic meters and 10 cubic meters and 12 cubic meters of mechanical transmission single buckets for large mines. Excavators, 1m3 tunnel excavators, 4m3 long arm excavators, 1000m3/h excavators, etc. We also developed marine hydraulic excavators with a bucket capacity of 0.25m3, a bucket capacity of 0.4m3, 0.6m cubic meters, 0.8 cubic meters of amphibious excavators, etc. But in general, the batches produced by Chinese excavators are small and scattered, and the production technology and product quality are far behind the international advanced level. Since the reform and opening up, it has actively introduced, digested and absorbed foreign advanced technology to promote the development of China's excavator industry. Among them, Guiyang Mining Machinery Factory, Shanghai Construction Machinery Factory, Hefei Mining Machinery Factory, and Changjiang Excavator Factory respectively introduced A912, R912, R942, A922, R922, R962, R972, R982 hydraulic excavators from Liebherr Company in Germany. machine manufacturing technology. A few years later, Hangzhou Heavy Machinery Factory introduced the production technology of H55 and H85 hydraulic excavators from Germany's Demag (Demag) company, and Beijing Construction Machinery Factory introduced RH6 and MH6 hydraulic excavators from Germany's O&K (0&K) company. Manufacturing Technology. At the same time, there are also Shandong Bulldozer General Factory (its excavator production base was renamed Shanxi Jian Machinery Co., Ltd., including two brands of STRONG and JCM), Yellow River Construction Machinery Factory, Jiangxi Changlin Machinery Factory, Shandong Linyi Construction Machinery Factory, etc. Jointly introduced the complete manufacturing technology of PC100, PC120, PC200, PC220, PC300, PC400 hydraulic excavators (except engines) from Komatsu, Japan. Through the digestion, absorption and transplantation of imported technologies for several years, the performance indicators of domestic hydraulic excavators have been comprehensively improved to the international level in the 1980s, and the output has also increased year by year. Due to the continuous increase and diversification of domestic demand for hydraulic excavators, the adjustment of the product structure of large and medium-sized state-owned enterprises has affected some manufacturers in other machinery industries to join the hydraulic excavator industry. Industry insiders pointed out that China's single-bucket hydraulic excavators should develop in the direction of full hydraulic pressure; the bucket capacity should be controlled at 0.1-15m³; and for large and multi-bucket excavators, due to the high requirements for the manufacture and assembly of hydraulic components, construction site maintenance conditions The difference is still mainly mechanical. Research and application of electro-hydraulic control technology should be started to realize the automation of hydraulic excavator operation. my country began to develop and develop excavator products in the late 1960s. After more than 40 years, especially the more than 30 years of reform and opening up, China's excavator manufacturing industry has developed rapidly. According to data from the National Bureau of Statistics, in 2010, there were 252 enterprises above designated size in China's excavator manufacturing industry, with sales of 169.785 billion yuan and product sales profits of 25.367 billion yuan, with a total profit of 21.406 billion yuan, a year-on-year increase of more than 80%. The Chinese excavator market is growing at an average rate of 30%, becoming one of the largest markets in the world. From the perspective of development, China is in the peak period of infrastructure construction in road transportation, energy and water conservancy, urban construction and other aspects, and the market demand for excavators is increasing year by year. Year-on-year growth reached 74.5%. At the end of 2010, major domestic enterprises expanded their production capacity of excavators one after another, and other companies opened up series of excavators one after another, trying to drive corporate profit growth through the rapid growth of the excavator market. In fact, considering both risk factors and benefits, bank credit was not active in promoting the construction of affordable housing, which indirectly led to the shrinking of construction machinery market sales in the second quarter of 2011. In May 2011, the domestic sales of excavators were 13,956 units, a year-on-year decrease of 12.4%, and the first monthly decrease was a year-on-year decrease; the cumulative sales from January to May was 115,589 units, a year-on-year increase of 38.1%, a decrease of 12 percentage points compared with January-April. On the whole, the domestic ownership of excavators is low, but the product price is high. The sales model is mainly based on financial leasing or bank mortgages. Once the credit is relaxed, the sales of excavators will be the best product to rebound. It can be predicted that in 2011-2013, with the recovery of the Chinese economy in the world, the acceleration of real estate and urbanization construction, the sales of excavators of various tonnages will also continue to grow. The machine will grow at a growth rate of over 15%. With the continuous intensification of competition in the excavator manufacturing industry, mergers and acquisitions and capital operations among large excavator manufacturing enterprises are becoming more and more frequent, and domestic excellent excavator manufacturing enterprises are paying more and more attention to the research on the industry market, especially the industry development environment and products. Buyer's in-depth research. It is precisely because of this that a large number of domestic excellent excavator brands have risen rapidly and have gradually become leaders in the excavator manufacturing industry in China and even the world.

​It has been more than 130 years since the first manual excavator came out. During this period, it has experienced the gradual transition from steam-driven semi-rotary excavators to electric-driven and internal-combustion-engine-driven full-rotation excavators, and fully automatic hydraulic excavators using electromechanical-hydraulic integration technology. development process. The production of excavators in industrially developed countries was earlier. France, Germany, the United States, Russia, and Japan are the main producers of single-bucket hydraulic excavators with a bucket capacity of 3.5-40m³. They have been producing extra-large excavators since the 1980s. For example, the stripping excavator with a bucket capacity of 50-150m³ produced by the American Marion Company, a walking dragline excavator with a bucket capacity of 132m³; Dragline excavators and excavators with a bucket capacity of 107m³ are currently the largest excavators in the world. Since the late 20th century, the international production of excavators has developed in the direction of large-scale, miniaturized, multi-functional, specialization and automation.

Longitudinal joints should use thermal joints as much as possible. Since the temperature of the mixture of two adjacent sheets during echelon operation is not much different, the material at the joints of the layers can still be extruded and has good adhesion, as long as a suitable lap joint is selected (Generally, the smaller the better, the maximum is 3 cm), and good lap quality can be obtained. If cold seams are used, they should be cut flush with the flat end plate of the screed or with a cutter after cooling to form a flat seam for easy control of subsequent laps.