Tractor Influencing Factors

1. Rolling resistance
The rolling resistance of the tractor is mainly caused by the deformation of the tires and the soil. Under the weight of the tractor, the tires are flattened and the soil is compacted. During the rolling process of the wheel, all parts of the tire that are in contact with the ground along the circumferential direction are flattened and deformed, and the soil that is raised in front of the wheel is pressed down to deform the soil and form wheel ruts, which creates obstacles that prevent the wheel from moving forward. Rolling resistance of rolling. There are many factors that affect rolling resistance, mainly related to factors such as the solidity of the ground and the degree of moisture, the size of the vertical load, and other factors. For the same tractor, if the ground conditions are different, the rolling resistance will also be different. For example, if the rolling resistance is small when driving on asphalt and cement or dry hard ground, the tractor's traction force will be large. Under the same conditions of use, if the rolling resistance added to the tires is The greater the weight, the greater the vertical deformation of the soil and the greater the rolling resistance. Generally speaking, reducing the deformation of the tire itself and the vertical deformation of the soil is beneficial to reducing rolling resistance. If the tractor is driving on soft ground, using low-pressure tires and increasing the tire support area can reduce the deformation of the soil in the vertical direction, reduce rolling resistance, and thus improve traction. Since tractors are mainly used for field operations and mostly travel on soft ground, in order to reduce the deformation of the soil in the vertical direction, tractors generally use the lowest pressure tires, and the same reason applies for widened tires. In our operations, we should pay attention to the differences in the use of low-pressure tires, widened tires and high-pressure tires.
2. Traction resistance
Traction resistance is the resistance that the tractor must overcome when driving agricultural machinery and equipment to operate. It is equal to the traction force transmitted from the tractor to the agricultural machinery and equipment through the connecting device. Since traction is equal to drive minus rolling resistance, increasing drive force and reducing rolling resistance are effective measures to improve traction.
3. Driving force
It is the horizontal reaction force of the road surface on the driving wheels. Therefore, the size of the driving torque Mk transmitted from the internal combustion engine to the driving wheels through the transmission system indicates that the tractor's driving force Pk is also greater. However, since Mk is determined by the power of the internal combustion engine, Pk is also limited by the power of the internal combustion engine. At the same time, Pk is limited by soil conditions and cannot increase indefinitely, because when the reaction force of the soil, that is, the driving force Pk, increases to a certain level, the soil is destroyed, the driving wheel slips severely, and the driving force Pk cannot be increased. We call the maximum reaction force that the soil can produce on the driving wheel "adhesion". It can be seen that the maximum value of the driving force Pk is not only limited by the internal combustion probability, but also limited by the soil adhesion, and cannot increase infinitely.
Adhesion reflects the ability of the drive to generate maximum driving force with the soil. There are many factors that affect adhesion, mainly related to ground conditions, tire pressure, size, pattern and the size of the vertical load acting on the tire. For tractors, under certain soil conditions, reducing the tire pressure within a certain range, increasing the tire support area, improving the wheel's ability to grip the soil, and increasing the attachment weight of the wheel are all conducive to improving the tractor's attachment. Focus on the use of low-pressure tires on tractors. Some tractors use widened tires and high-pattern tires, as well as adding counterweights to the tractor drive wheels. These are all measures taken to increase the tractor's adhesion and improve the tractor's traction capacity. . However, it should be pointed out that adding counterweight iron to the driving wheel can increase adhesion, but it also increases the deformation of the soil in the vertical direction and increases rolling resistance. Therefore, whether to add counterweight iron depends on the specific use conditions and weighs the overall Effects are selected.
The maximum adhesion capacity and the ability to resist slipping between the tractor's driving wheels and the ground are called the tractor's adhesion performance. If the adhesion performance is good and the slippage is light, the driving torque can be fully utilized, the ability of the internal combustion engine can also be fully exerted, and the tractor will appear powerful when working. If the adhesion performance is poor and the slippage is serious, the driving torque cannot be fully utilized and the capability of the internal combustion engine cannot be fully exerted. The tractor will not be powerful when working, or the tractor will not have much power. Severe slippage of the driving wheels will reduce the tractor's driving speed, reduce production and economy, and also accelerate the wear of the driving wheel tires. In addition, the soil structure will also be damaged.