In recent 50 years, the competition between mechanical transmission and electric drive has been fierce. In the 60-70 century of the last century, because of the development of large power hydraulic torque converter and other equipment, the mechanical transmission mine truck has been difficult to scale up. As a result, the electric wheel coal mine vehicle took advantage of the trend to rise, almost all occupied the 100 ton level of mining vehicle market. Until 1983, the American Caterpillar type 785 and Japanese Komatsu's HD-1200M came out, the mechanical drive model gradually entered the 100 ton grade mining car market, but the market share was only 2-3%. Since the mid and late 80s, due to the development of technology and the successful development of the large hydraulic torque converter of Allison company in the United States, the mechanical transmission model has been developed rapidly. The market share is now around 3-4, the main manufacturer is the American Caterpillar, its largest model 797F, and the load has reached 400 tons (363 tons). The most in the world.
The development of mechanical models has forced motorized wheel models to escalate. Since the late 80s, computer control, vehicle fault diagnosis, auto speed regulation, diesel fuel injection and other technologies have been widely used in electric wheel vehicles. In the late 90s, with the development of AC frequency conversion technology and the advent of high-power inverters, the mining electric wheel trucks have entered the era of AC and AC direct transmission. Japanese Komatsu, at the Chicago International Fair in 1996, exhibited the first 930E type mining vehicle with AC transmission, the first model of the world's first load of 300 short tons, with an AC torque control system with a maximum speed of 64.5km/h. In addition, Euclid-Hitachi, in collaboration with German SIEMENS, launched the R260 type (now EH4500 type) AC drive mine electric wheel dump truck in 1997, and put it into commercial production in 1998.
Since 1963, since the United States began to mass produce 77 tons of electric wheel dump trucks in mass production, the weight of mine vehicles has been increasing continuously. It has developed a number of 108 tons, 120 tons, 154 tons, 170 tons, 220 tons, 280 tons, 320 tons, 360 tons and so on. The minitype mines with annual output of million tons are more than 25-70 tons, and 500-1000 tons of medium-sized mines with a yearly output of 100-220 tons, and more than 10 million tons of large mines with more than 150-360 tons. In recent years, with the continuous expansion of mining scale, large tonnage mine trucks are listed on the market.
These giant cars, like mobile steel castles, sell for more than $4 million. The width of the body is nearly 10 meters, which is equivalent to 5 cars running side by side. The height is nearly 8 meters, which is equivalent to three storeys. The empty car weighs more than 230 tons, the maximum load can reach 363 tons, and the electric shovel must be filled with 3-4 shovels. Because the mining vehicle is too large, it has exceeded the limit of highway load, so it is also called "off road vehicle". They can only be transported to the mining area in the form of parts and assembled after mining on special roads in the mining area. Compared with table tennis and basketball, the earthcars we see everyday are compared with them.
The 24 cylinder diesel engine of a large mining vehicle is more than 10 tons, with a displacement of more than 100 liters. The total power is more than 3700 horsepower, which is enough to pull a train. So large power, oil consumption is natural astonishing. Their 100 kilometer fuel consumption is nearly 900 litres, and the fuel tank capacity is as high as 7500 litres. The average fuel consumption of a family car is only 10 litres, and the fuel tank capacity is only about 60 litres. Their tires are the largest giant tires in the world. A single tire weighs more than 5 tons and is more than 4 meters in diameter. It sells for nearly $50 thousand. It is required to use professional machinery to load and unload the tires. Because the body is too high, the cab's line of sight is very blind. Small vehicles such as pickup and Jeep in the mining area must tie the flagpole and hang the red flag at the end of the car to remind the drivers of the large mining vehicles to prevent the rolling accidents. It is said that when a mine truck rolls over a car, it feels as if people are stepping on a small stone when they walk. It is difficult for the driver to distinguish whether or not it is rolling into other vehicles.
In addition, the mining dump truck should adapt to the extreme bad environment. The coal field in northern China and the oil sand mine in the northern permafrost zone of the northern Canada are around zero 40 degrees below zero in winter. Australia's iron ore and South African gold mines are in hot weather all the year round. In such an extreme environment, a properly maintained mining vehicle has a working life of more than 60000 hours (about 15-20 years), and a million tons of ore or divestiture should be transported every year. These extremely harsh conditions have put forward high requirements for the reliability, safety and economy of mining vehicles. The development process involves many fields, such as structural design, metallurgical welding, electrical control, hydraulic technology, giant tire manufacturing, new material application and so on, which can be called the essence of modern industrial technology. Therefore, only a few enterprises in the world can develop 200 tons of mine trucks. Xiangdian group is the first enterprise in China to have such strength.
