Loaders are earth-moving machinery widely used in highways, railways, construction, hydropower, ports, mines, and other construction projects. They are mainly used for shoveling, loading, unloading, soil and stone, and other bulk materials. Lightly excavate rock and hard soil. If you change to a different working device, you can also complete the work of bulldozing, lifting, loading, and unloading other materials. In highway construction, it is mainly used for filling and excavation of roadbed engineering, as well as for aggregate and loading operations of asphalt and cement concrete yards. Because it has the advantages of fast working speed, good maneuverability, and light operation, it has developed rapidly and has become the main machinery in earth and stone construction.
The commonly used single-bucket loaders are classified according to the engine power, transmission mode, walking system structure, and loading method.
A small loader with a power of less than 74kw.
The power is 74～147kw for the medium-sized loader.
The power is between 147～515kw for the large loader.
The power is greater than 515kw for the extra-large loader.
Hydraulic-mechanical transmission, small impact, and vibration, the long service life of transmission parts, Convenient operation, the vehicle speed, and external load room can be automatically adjusted, generally used in medium and large loaders;
Hydraulic Transmission: stepless speed regulation, convenient control room, but poor stability, generally only used on small loaders;
Electric drive: stepless speed regulation, reliable work, simple maintenance, high cost, generally used on large loaders.
Tire type: lightweight, fast speed, flexible maneuverability, high efficiency, not easily damage the road surface, large ground contact pressure, poor passability, but it is widely used;
Crawler type: low ground contact pressure, good passability, Low center of gravity, good stability, strong adhesion, large traction, large specific cutting force, low speed, relatively poor flexibility, high cost, easy to damage the road surface when walking.
Front unloading type: simple structure, reliable work, good vision, suitable for various working sites, and wide application;
Rotary type: the working device is installed on a turntable that can rotate 360O, and the side unloading does not need to turn around, The work efficiency is high, but the structure is complex, the quality is high, the cost is high, and the lateral stability is poor. It is suitable for smaller venues.
Rear unloading type: front loading, rear unloading, high work efficiency, poor work safety.
Model selection: The selection and determination are mainly based on the operating occasion and purpose. Generally, crawler loaders are used for operations in quarries and soft bases;
Power selection: Generally, diesel engines for construction machinery are generally used. For operations in special areas, such as places with altitudes higher than 3000m, special ones should be used. High prototype diesel engine;
Selection of transmission type: Generally, hydraulic-mechanical transmission is used. The key component is the choice of the torque converter form. At present, most of the loaders produced in my country use dual-turbine, single-stage, two-phase torque devices.
When selecting a loader, the braking performance of the loader must be fully considered, including multiple brakes, parking brakes, and emergency brakes. There are three types of brakes: shoe type, caliper disc type, and wet multi-disc type. The driving mechanism of the brake generally adopts an afterburner, and its power source has three types: compressed air, air cap oil, and hydraulic. At present, the air-cap oil braking system is commonly used, and a dual-circuit braking system is generally used to improve driving safety.