BelAZ-75710: carrying capacity 450 tons
The car was presented to the general public at the very end of September, and in November we arrived at the factory to personally make sure that the giant is not a show car or a car specifically for the Guinness Book of Records (although, of course, it will be listed there soon). No, BelAZ-75710 is a workhorse, a serious mining truck, already heading for Kuzbass quarries. And this is only the first car, an agreement has been reached to create two more giants.
The first question that we asked our consultant sounded simple: “Why?” After all, there is a certain logical boundary, raising the carrying capacity above which does not make sense, and sometimes it is impossible! The thing is that the cost of transporting a ton of cargo directly depends on the capacity of the mining truck. Simply put, the higher the payload, the lower the cost. Two 225-ton trucks in production and operation will cost significantly more than one twice as large dump truck. Oddly enough, the need for such a giant warmed up the global economic crisis: the profitability of minerals fell significantly, and there was a need to reduce the cost of production and transportation. Then BelAZ appeared.
However, talk about the car began a long time ago. Preliminary negotiations with potential buyers were successful, and BelAZ decided on production. Now the car has already been bought, and the next chassis will begin to be assembled in the first half of 2014. Assembling the giant - of course, not a conveyor belt, but a guard station, almost manual - takes only two months, and they developed the car in record time - exactly two years passed from the conceptual design to the exit from the workshop.
Basically, the 75710 is a new class. It is difficult to combine with dump trucks lifting from 320 to 363 tons - they have other constructive solutions, sometimes a different layout. Actually, even outwardly, the giant is completely unlike other mining vehicles, but the most surprising lies inside.
For such a huge car, the most important indicator is maneuverability, especially since career work requires a fairly accurate approach to the place of loading and driving in difficult road conditions. To rotate the designers used two slewing rings, two hinges. Each such node resembles an inverted excavator, only the bottom of the excavator is fixed, and the tower rotates, the upper part remains stationary, and the bridges turn. At the very beginning of the development, there were thoughts about an articulated system with a “breaking” frame, but there is a very weak point in this design - the hinge itself, the failure of which turns the truck into a pile of metal. BelAZ-75710 lacks such a drawback. Its frame consists of three elements - the main frame and two frames of rotary devices, coupled to the base with three-row roller bearings with a diameter of 2.75 m. Each axis is rotated using two hydraulic cylinders: one pushes, the other pulls, or vice versa. However, everything in the car on hydraulics - and management, and lifting the body, and the brake system. From pneumatics - only a starter. This is a world practice: from factories producing mining equipment, only Komatsu holds onto pneumatic systems, the rest have long switched to hydraulics - it is simpler and more reliable.
A turn occurs as follows: the driver turns the steering wheel while controlling the hydraulic pump, and the system applies pressure to the turning cylinders. Bridges move separately: first, the front one rotates to the extreme position, then the rear one rotates. But the scheme is being improved - and the possibility of simultaneously turning bridges has already been realized, which greatly reduces the turning radius (today it is 19.8 m with a total vehicle length of 20 m). The plans include the possibility of simultaneously turning bridges in one direction so that the machine can move “crab”, but this system will be implemented on other dump trucks of the series.
In case the hydraulic steering system for some reason fails, BelAZ is equipped with pneumatic hydraulic accumulators for steering. There is enough pressure in them to turn the axles once from one extreme position to another - this will allow in an emergency to get off the road, giving way to another dump truck. On a 360-toner, only two of these cylinders are enough, as many as six are installed here.
It is interesting that for the first time in the career technology, Belarusians used struts of anti-roll bars. This is the know-how of BelAZ: stabilizers provide both a smooth ride and lateral stability from tipping over.
In addition to the hydraulic steering system, the engine compartment is of great interest. It is comparable in size to the living room of an ordinary city apartment, you can walk along it, and if necessary, you can even temporarily settle down. Of course, after the development of a resource by a dump truck. Two MTU DD 16V4000 diesel engines rated at 2, 330 hp each (an empty truck can move on one diesel engine) is connected to generators. Generators generate current, which, depending on the load, is transmitted to electric motor-wheels. Thus, in the car there are both interaxle and interboard electrical differentials - how much energy is needed to rotate each individual wheel at a given moment, so much is spent.
An interesting exhaust gas system from diesel engines. From one gas through the muffler are output to the side - nothing special. But from another they come through a gas receiver ... to the platform (namely the platform, not the body, as some say). The bottom line is that when working in the north, the soil freezes, and the platform needs to be constantly heated. Using exhaust gases for this is the most rational solution, in addition, the platform itself also serves as a silencer.
A giant on closer inspection consists of hundreds of elements, each of which has its own purpose, which is not always clear at first glance. Therefore, "crawling" around the car (you can’t say otherwise - the feeling is exclusively ant), we paid special attention to details.
For example, transverse ribs are welded onto the platform. What for? After all, they will interfere with the unloading of ore! Everything is simple. The fact is that upon delivery to the customer, the dump truck is disassembled practically by a screw. BelAZ’s frame alone occupies three (!) Railway platforms - it rests on one and hangs over two. The platform is also collapsible: the sides are removed, and the plane is disassembled into three parts. At the place of direct work, the platform is assembled and scalded. But the dump truck needs to be tested somehow at the factory, moreover, together with the platform, but it is impossible to weld it, because the parts have a complex shape, you cannot cut back without damage. Therefore, for testing, the three components of the platform are temporarily fastened with welded channels, which are easily cut off before transportation. A similar purpose is served by the welded hooks and chains we noticed in the back of the body - purely for installation.
Behind a raised platform, powerful cables are visible connecting it to the frame. This is insurance: if suddenly the lifting hydraulic cylinder fails, the 78-ton platform will go down in 15 seconds, and if there are workers on the frame, this is fraught with grave consequences. Locking cables in extreme cases will keep the body from abrupt lowering.
For those who are new to the career equipment, BelAZ (as, incidentally, other giant dump trucks) has one more surprising discovery. Those round shiny elements in the front that most people take as headlights when looking at pictures are actually air filters. There are eight of them on BelAZ-75710. The air intake is from below, and the round openings closed with reflective covers are purely technological, for mounting and replacing filters. The headlights are at the bottom - six small square LED lights. This is quite enough.
The truck has standard tires - Bridgestone 59 / 80R63, the same tires are used on most mining trucks. Today, only Bridgestone and Michelin make tires of this dimension, but next year the release of the Goodyear analogue was announced, and in a year the Belarusian Belshina will produce rubber for supergiants. The load capacity of one tire is 101.6 tons, that is, eight wheels are designed for 812.8 tons (the total maximum mass of the truck is 810 tons).
Right off the bat
When we left, the dump truck was already beginning to be dismantled for sending to the customer, that is, we were lucky - we managed. BelAZ specialists will assemble it on the spot - a whole group is sent together with the machine. Oddly enough, the resource of such machines is small - five to six years of work. How is it, you ask, because ordinary cars sometimes drive for 30 years! But the point is in the operating conditions. The mining dump truck is designed to be used 23 hours a day (an “extra” hour is formed from two half-hour breaks for refueling, a brief inspection and a change of driver). The average mileage for a “career” reaches 600, 000 km. No machine can withstand such a regime with such loads, so in this case it is a very long service life. After decommissioning, mining trucks usually go to spare parts for their "working" colleagues.
A common question: how much fuel does such BelAZ “eat”? Frankly speaking - decently (but - it is necessary to repeat - less than would consume two half the smaller truck). The technical data does not indicate a very clear figure: the specific fuel consumption at rated power is 198 g / kW · h. Simply put, in a 12-hour cycle, the truck “eats up” two tanks of 2800 liters each, that is, more than 5000 liters of diesel fuel per shift. However, it is worth making a reservation: this is the maximum flow rate with a fully loaded truck, as if it had been moving at maximum speed and 450 tons of rock for 12 hours. Of course, in fact, it consumes significantly less fuel. You can refuel in the usual way, through the neck, but to speed up the process, special refueling devices are used, similar to those previously used in Formula 1.
|Comparison of the parameters of the largest dump trucks in the world||BelAZ 757710||Caterpillar 797f||Liebherr 282B||Bucyrus MT6300AC|
|Carrying capacity, t||450||363||363||363|
|Engine||2 x MTU DD 16V4000||Cat C175−20 Acept||DDC / MTU 20V4000||DDC / MTU 20V4000|
|Engine power hp (kW)||2x2330 (1715)||4055 (2983)||3650 (2720)||3650 (2720)|
|Tires||59 / 80R63||59 / 80R63||59 / 80R63||59 / 80R63|
|Gross weight, t||810||623.7||596.9||603.3|
|Max. speed, km / h||64||68||64||64|
|Fuel tank volume, l||2x2800||3785||4732||4920|
|Length mm||20, 600||15, 090||15 320||15 570|
In Soviet times, car factories had a very high localization of production - up to 80% of parts and components were produced in one place. Abroad, on the contrary, components are ordered from dozens and even hundreds of highly specialized firms. In this sense, BelAZ is a European-type plant. At the factory itself, just under 50% of the parts are made. High-strength Swedish steel Weldox 800, MTU engines, Siemens electrical systems, Bosch hydraulics, rubber, fire extinguishing system, centralized lubrication system are purchased. At the same time, most of the purchased is created at other plants according to the “BelAZ” drawings specifically for Belarusian equipment - narrow specialization always allows to achieve higher quality. Bridges, frames, platforms, cabins, plumage, hubs, gears of motor wheels are made directly at BelAZ, but the main thing that is here in Zhodino is bright heads. Trucks are fully developed based on experience gained over more than half a century.
Of course, such machines have very limited use - because there are less than a dozen of them in the world. But the demand is great, and the plant does not work at a loss - giants are made exclusively by prior arrangement with the customer. There is a conveyor at BelAZ (we wrote about it in March 2009), but cars of up to 220 tons are assembled on it. For heavier trucks, a post assembly is used. And therefore, when you hear the creators of the Rolls-Royces or Maserati boasting the manual assembly and uniqueness of their cars, remember the Belarusian giants. This is real manual work and really complex and original technical solutions. Here, excessive pathos is not required. With 450 tons, this simply does not make sense - the numbers speak for themselves.
The editors are grateful for the help in preparing the material of BELAZ OJSC and personally to the design engineer of the design bureau Alexander Naskovets for an interesting and qualified story about the machine.The article “BelAZ Iron Record” was published in the magazine Popular Mechanics (No. 1, January 2014).