How crawler tractors work

Crawler tractors are different from wheeled tractors in that they are supported on the ground by a wound ring track. The crawler tracks are in contact with the ground, the spikes are inserted into the soil, and the driver is not grounded. Under the action of driving torque, the driving wheel continuously rolls up the crawler track from the rear through the engagement between the gear teeth on the driving wheel and the track shoe joint pin. The part of the track that touches the ground exerts a backward force on the ground, and accordingly a forward reaction force P is given to the track. This P is the driving force that drives the tractor forward. The driving force of a wheeled tractor is directly transmitted to the running wheels, unlike a crawler tractor. Its driving force P is transmitted to the axle of the driving wheel through the crawler track wrapped around the driving wheel, and then transmitted from the axle through the tractor's body. onto the drive wheels. When the driving force is sufficient to overcome the rolling resistance and the traction resistance of the farm implements, the track wheels roll forward on the upper surface of the track, causing the tractor to move forward. Since the driving wheel continuously rolls the track forward one by one, and then spreads it on the ground through the guide wheel, the track wheel can continuously roll on the track laid with the track. It can be seen that the movement of a crawler tractor is achieved by the interaction between the track and the ground caused by the driving torque through the driving wheel, and the driving force is greater than the sum of rolling resistance and traction resistance. The maximum driving force is the same as that of a wheeled tractor. On the one hand, it depends on the capability 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 more powerful 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, reasonable selection of the shape and size of the track spurs and track, and increasing the weight of the track within a certain limit can 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 traction of the tractor.