Views: 104 Author: Site Editor Publish Time: 2019-11-29 Origin: Site
Mining dump truck is a kind of heavy dump truck used in open-pit mine to complete the task of rock and earth stripping and ore transportation. Its working characteristics are short transportation distance and heavy load. It is usually loaded by large electric shovel or hydraulic shovel, and goes back and forth from the mining point to ore unloading point. Mining dump truck products have decades of development history, now the basic technology has been very mature.
At present, rigid frame dump truck is widely used. The following is a brief description of its structural characteristics.
The mining dump truck can only run in a limited mining area, and the overall dimension of the truck is not limited. In order to improve the transportation volume of each vehicle, it is inevitable to increase the volume of the car as much as possible, as well as widen and heighten the overall dimension of the whole vehicle. Its width far exceeds the width of the road vehicles specified in the national JTGB01-2003”Highway Engineering Technical Standard”and GB1589-2004“Limits of the Overall Dimension, Axle Load and Quality of Road Vehicles”. If a road vehicle exceeds the limit of 2.5m, it is not allowed to drive on the road.
At present the load of this kind of vehicle is between 20-360 tons, and it is still developing towards large-scale. Due to the large load tonnage and many slopes on the road, the engine must have high power and high torque to ensure that it is also easy and powerful when it is loaded uphill. Therefore, all these models are equipped with engineering engines with high "specific torque" and high "torque increase coefficient". However, due to the poor off-road working conditions, the common speed of these vehicles is about 30-40km / h.
There is the narrow area of the loading and unloading sites in the mining area, and frequent turning and reversing. The roads in the mining area are mostly temporary roads, and there are many uphill and downhill in the mountain area, and also many sharp turns. In order to maintain the flexibility, the wheelbase and the total length have to be shortened so as to reduce the turning radius and the number of reversing. Thus the 2-axis 4 × 2 structure is adopted, which can ensure the simple structure of the chassis, convenient maintenance, and sensitive steering. For such vehicles, the single axle load far exceeds the limit value of 12 tons specified in GB1589-2004“Limits of the Overall Dimension, Axle Load and Quality of Road Vehicles”. It cannot be driven on the road.
The frame is a special structure for engineering machinery vehicles, all of which are fully welded. The longitudinal beam adopts closed box section to ensure high torsional strength. The thick steel plates used are all low alloy and high-strength steel plates.
The carriage is also a fully welded structure with the back of the bucket type floor cocked up, a general slope angle of 12 degrees, and no rear baffle. The bottom plate is welded by high-quality steel plates with high strength, hardness and impact resistance to adapt to the transportation of off-highway poor industrial and mining areas and rough stone loading on the project sites, moreover its service life is generally over 10 years. The latest generation of energy-saving body represented by Australian technology adopts higher strength alloy steel. Compared with the traditional body, it reduces the weight of the body by more than 20% and saves 8% oil. The maintenance frequency is reduced by 30%.
Most of the mining dump trucks use hydro pneumatic suspension, especially the trucks with a load capacity of more than 45 tons are almost no exception. This kind of vehicle with short wheelbase and high quality is most suitable for the installation and use of hydro pneumatic suspension. It has no corresponding space to install the traditional leaf spring damping. The hydro pneumatic spring cylinder of the front wheel also has the function of steering master pin, and the outer cylinder is fastened on the outside of the frame longitudinal beam, so the traditional integral front axle is omitted.
Due to the large mass of the whole vehicle and the load of the front axle, the steering of the front wheel is completely dependent on hydraulic power. In order to ensure the safety and reliability of steering, this kind of vehicle not only adopts full hydraulic steering, but also is equipped with emergency steering system. When the power of steering system fails, the emergency steering system can ensure that it has a certain steering capacity, so that the vehicle can park in a safe place.
There are many slopes in the mining area, and the vehicle load is particularly large. Therefore, the reliability of the brake system function also needs to be guaranteed first. In addition to the main brake function of dump truck, it is also equipped with auxiliary retarder braking ability. The engine exhaust brake, hydraulic retarder or electric wheel can be transformed into the electric retarder of generator. The brake function design is advanced. At the beginning of braking, the engine exhaust brake is put into operation first; then the hydraulic retarder or electric retarder join the retarder function together; finally, the wheel main brake is also put into operation. Thus, the service frequency of the main brake is greatly reduced. It is often in the best state, and the service life of the brake shoe is prolonged.
Hydraulic mechanical transmission and traditional rear axle are generally used for vehicles with a load capacity of less than 100t. Electric drive is generally used for vehicles with a mass capacity of more than 100t. In the latter mode, the engine drives the generator, and then the electric motor in the rear wheel is driven by the current, so that the rear wheel drives the vehicle.
The tread pattern and structure of these tyres are different from those of road vehicles, which belong to engineering tyres, so as to well adapt to the application requirements of complex roads.
This kind of vehicle has special terms (called off-highway trucks or off-road trucks) in the world, belonging to the category of earth moving machinery (TC127 Standard Organization. This product does not belong to the management scope of the national "Vehicle Production Enterprises and Product Announcement”. This type of vehicle is not included in the catalogue of production enterprises in the automobile industry published by the state.