How Does A Crawler Tractor Work?

Crawler tractors are different from wheeled tractors in that they are supported on the ground by a wound circular crawler track. The crawler track contacts the ground, the spikes are inserted into the soil, and the driver is not grounded. Under the action of the driving torque, the driving wheel continuously rolls up the crawler track from the rear through the meshing between the gear teeth on the driving wheel and the track plate joint pin. The grounded part of the crawler track exerts a backward force on the ground, and the crawler track also exerts a forward reaction force Pk accordingly. This Pk reaction is the driving force that pushes the tractor forward. The driving force of a wheeled tractor is directly transmitted to the traveling wheel, but the crawler tractor is different. Its driving force Pk is transmitted to the axle of the driving wheel through the crawler track wound on the driving wheel, and then transmitted to the driving wheel through the axle through the tractor body. When the driving force is sufficient to overcome the rolling resistance and the traction resistance of the agricultural implements carried, the supporting wheels roll forward on the upper surface of the crawler track, so that the tractor moves forward. Since the driving wheel continuously rolls the crawler track to the front section by section and then lays it on the ground through the guide wheel, the supporting wheel can continuously roll on the track laid by the crawler track. It can be seen that the movement of crawler tractors is achieved by the interaction between the crawler track and the ground through the driving wheel, and the driving force is greater than the sum of the rolling resistance and the traction resistance.
The maximum driving force is the same as that of wheeled tractors. On the one hand, it depends on the capacity of the internal combustion engine, and on the other hand, it is limited by the adhesion conditions between the crawler track and the ground. Generally speaking, the greater the power of the tractor, the greater the driving force. There are many factors that affect adhesion. As far as the structure of the tractor itself is concerned, the reasonable selection of the shape and size of the spurs and crawlers, and the increase of the crawler track's bearing weight within a certain limit can all improve adhesion and increase the tractor's traction. The rolling resistance of a crawler tractor is formed by the deformation of the soil in the vertical direction and the mutual friction between the various parts of the walking system. Reducing the rolling resistance can increase the tractor's traction.