Tractor is a self-propelled engine used to pull and drive operating machinery to complete various mobile operations. Can also do fixed work power. It is composed of engine, transmission, walking, steering, hydraulic suspension, power output, electrical instruments, driving control and traction systems or devices. The engine power is transferred from the transmission system to the driving wheel to make the tractor drive. In real life, it is common to use rubber belt as the medium of power transmission. Agricultural, industrial and special purpose tractors by function and use; According to the structure type of wheel type, crawler type, boat tractor and self-propelled chassis and so on.
Factors affecting the progress of tractors:
1. Rolling resistance. The rolling resistance of the tractor is mainly caused by the deformation of the tire and soil. Under the action of the tractor's weight, the tire is flattened and the soil is compacted. In the rolling process of the wheel, the parts of the tire in contact with the ground along the direction around the circle are flattened and deformed, and the high soil in front of the wheel is pressed down to deform the soil and form wheel ruts, that is, the rolling resistance that prevents the wheel from rolling forward. There are many factors affecting rolling resistance, which are mainly related to the firmness of the ground and the size of the vertical load on the degree of moisture. For the same tractor, if the ground conditions are different, its rolling resistance is different, such as in asphalt and cement or dry ground driving rolling resistance is small, tractor traction is large, in the same use conditions, if added to the weight of the tire, the greater the soil deformation in the vertical direction, the greater the rolling resistance. Generally speaking, reducing the deformation of the tire itself and the deformation of the soil in the vertical direction is conducive to reducing rolling resistance. If the tractor is driving on soft ground, the use of low pressure tires, increase the tire bearing area, can reduce the soil deformation in the vertical direction, reduce the rolling resistance, so as to improve the traction. Because the tractor is mainly used for field operations, mostly driving on soft ground, in order to reduce the soil deformation in the vertical direction, so the tractor generally uses the lowest pressure tire, using the widened tire is the same reason. In our operation, we should pay attention to the difference between low pressure tires, widened tires and high pressure tires in use.
