Dump trucks mainly transport sand, stone, earth, garbage, building materials, coal, ore, food, and agricultural products, etc., in bulk and in bulk. Its greatest advantage is the realization of the mechanization of unloading, thereby improving the efficiency of unloading, reducing labor intensity and saving labor. Therefore, it has been rapidly developed and popularized both at home and abroad for decades, and its ownership has accounted for about 25 % of the special-purpose vehicles so far , and it has become increasingly sophisticated and has become a series of multi-variety products. It has the following multiple classifications.
1 . Classification by purpose
　　 Generally divided into two categories according to their use: - ordinary dump trucks belonging to road transport; and other heavy dump trucks belonging to non-road transport, mainly used for mining operations and large and medium-sized civil engineering works.
2 . Classified by loading quality level
　　 Dump be divided into light (which is generally less than the loading mass 3 5t.); Dump Medium (4t ~ 8t); V heavy dump truck to 8t).
3 . According to transmission type
　　 Can be divided into mechanical transmission, hydraulic mechanical transmission and electric drive three types. 30t dump truck load following major mechanical transmission; 80t heavy-duty dump truck load more and more use of electric drive.
4 . Classified by way of unloading
　　 There are a variety of forms such as backward tilting, rollover, three-side dumping, bottom dumping, and lifting and tilting of containers. One of the most widely used backward tilting applications. The side unloading type is only suitable for difficult situations where the lane is narrow and the unloading direction is changed. Lifting and tilting of the container is suitable for occasions where the goods are stacked, converted and moved to a higher position. Bottom dumping and dumping on three sides are used for a few special occasions.
5 . Classified by dumping agency
　　 Divided straight dump trucks and lever lift dump trucks. Push-type can be subdivided into single-cylinder, double-cylinder, multi-class and so on. Leverage can be subdivided into front-mounted leverage, rear-mounted leverage, neutral-mounted leverage.
6 . Classified by car structure
　　 According to the structure of the gateboard, it is divided into one open type, three open types, and no rear type ( 簸箕 ) . According to the cross-section of the bottom plate, it can be divided into rectangular type, bottom type and arc bottom type.
 Second, the structural characteristics
　　 Ordinary dump trucks are generally designed to be modified on the basis of the second-class truck chassis ( called the second-class chassis when the trucks are removed from the freight cars ) . Usually consists of chassis, power transmission, hydraulic dumping mechanism, sub-frames, and dedicated containers. The total mass of less than 19t ordinary dump truck, the general formula FR4 × 2 types of chassis, i.e., front engine rear axle drive arrangement. Dump trucks with a total mass of more than 19t use 6×4 or 6×2 drives.
The power transmission of the lift mechanism generally mounts the power take-off power from the top or side of the transmission assembly. The power take-off device directly drives the oil pump or drives the oil pump through the drive shaft to generate the hydraulic drive force.
 The hydraulic part is generally composed of a fuel tank, an oil filter, an oil pump, a check valve, a rotary valve, a discharge valve, a sub-fluid, an oil cylinder, an oil pipe, etc. to form a typical dumper structure.
The tipper of dump truck consists of the following three basic parts;
 Dumping mechanism It is composed of cargo compartment, sub-frame, hinge shaft and dump lever mechanism.
 Hydraulic drive system It consists of power take-off device, drive shaft, oil pump, pipeline system, lift cylinder and distribution valve.
 Attachment system The safety prop, lifting limit device, rear box panel automatic opening and closing device, container drop guide plate, and sub-frame connecting device.
 Heavy duty dump trucks have many different characteristics from ordinary dump trucks due to the special requirements of use and the constraints of the use environment. If the load is large, the vehicle speed is low, the transport distance is short, and its axle load is not limited by highway regulations, it can be selected to be large, and it has good passability and mobility under bad road conditions. Therefore, a chassis must be specially designed. The entire vehicle adopts the FR4X2 short wheelbase rear unloading form. Its cab is generally flat-head offset. The well-sealed single-seat cab is arranged parallel to the side of the engine. It has the advantages of wide field of vision, good ventilation, easy power maintenance, and high vehicle area utilization. The transmission system has two forms of mechanical transmission and electric transmission. Suspension mostly uses leaf springs, but also uses rubber suspensions or silicone oil suspensions. Braking system is dynamic braking. Among them, medium- and small-tonnage vehicles use pneumatic braking, while large-tonnage vehicles use more oil-gas brakes ( cylinder oil ) , and advanced high-pressure full-hydraulic brakes have emerged. Container lifting mechanisms generally use front-end push-type.
The dump truck is mainly composed of a hydraulic dumping mechanism, carriages, frames, and accessories. The hydraulic dumping mechanism and the refitting structures of the compartments are not the same. The structure of the dump truck will be described in terms of the type of the compartments and the lifting mechanism.
1 compartment type
The type of car body mechanism can be divided into different types depending on the purpose: ordinary rectangular cars and mining bucket cars.
Ordinary rectangular cars are used for bulk cargo transportation. The rear plate is equipped with an automatic opening and closing mechanism to ensure the smooth discharge of the goods. The thickness of the ordinary rectangular carriage is: front panel 4~6 , side panel 4~8 , rear panel 5~8 , bottom panel 6~12 . For example, the standard configuration plate thickness of the ordinary rectangular dump trucks is: the first 4 sides, the 4th base, the 8th and the 5th .
The mining bucket compartment is suitable for the transportation of large-grained cargoes such as large rocks. Taking into account the impact of the cargo and the collision of buildings, the design of mine bucket cars is more complex and the materials used are thicker. For example, the standard plate thickness of the Qingdui Dump Truck Mine Dump Truck is: the first 6 sides are 6 bottom 10 , and some models are welded with some angles on the floor to increase the rigidity and impact resistance of the carriage.
2 lifting mechanism type
The lifting mechanism is the core of the dump truck and is the primary indicator for judging the pros and cons of the dump truck.
The type of lifting mechanism currently common in China is: F -type tripod amplification lifting mechanism, T -type tripod amplification lifting mechanism, two-cylinder lifting, front lift and double-sided rollover
The tripod amplification type lifting mechanism is currently the most used lifting method in the country, and it is suitable for a load capacity of 8 to 40 tons and a carriage length of 4.4 to 6 meters. The advantages are that the structure is mature, the lift is stable, and the cost is low; the disadvantage is that the closed height of the upper plane of the cabin floor and the main frame is relatively large.
Most of the twin-cylinder lifting models are used on 6X4 dump trucks. A multi-stage cylinder (typically grade 3 to 4 ) is installed on both sides of the front of the second bridge . The fulcrum on the hydraulic cylinder acts directly on the floor of the cabin. The advantage of double-cylinder lift is that the closed height of the upper plane of the cabin floor and the main frame is small; the disadvantage is that it is difficult for the hydraulic system to ensure the synchronization of the two hydraulic cylinders, the stability of the lift is poor, and the overall stiffness of the floor of the cabin is required to be high.
The structure of the front top lift is simple, the closed height of the plane between the floor of the cabin and the main frame can be very small, the stability of the whole vehicle is good, the pressure of the hydraulic system is small, but the stroke of the front top multi-stage cylinder is relatively large and the construction cost is high.
The double-side rollover hydraulic cylinder has better force and less stroke, and it can realize double-side rollover; however, the hydraulic piping is more complicated and the occurrence rate of lift accidents is higher.
Dump Truck Selection
   With the development of dump trucks and the increase in domestic purchasing capacity, dump trucks are no longer a traditional dump truck that can do anything, from the design perspective.   It is also based on different goods, different working conditions, and different regions to develop different products. This requires the user to provide the manufacturer with specific usage when purchasing the vehicle.
1 chassis
When choosing the chassis, it is generally considered in terms of economic benefits, such as chassis price, loading quality, overload capacity, fuel consumption per 100 km, and road maintenance fees. In addition, the user also needs to consider the following parameters of the chassis:
1 The height of the chassis frame is above the ground. General 6x4 chassis frame above the ground from the height of 1050 ~ 1200 . The higher the value is, the higher the vehicle's center of gravity is and the easier it will be to roll over. The factors that affect this value are mainly the diameter of the tire, the arrangement of the suspension and the height of the main frame section.
2 Chassis hanging behind. The excessive value of this value will affect the stability of dump trucks and cause accidents. This value is generally between 500-1100 (except rollover dump trucks).
3 The vehicle is reasonable and reliable to use.
2 tops
At present, dump truck manufacturers are mixed, and choosing a dump truck is not as important as choosing a manufacturer. In addition to looking at products, we must also understand the manufacturer's equipment capabilities, design of dump trucks, the maturity of process equipment, after-sales service commitments, and whether accessories can be purchased.
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