Investigation of front plough functioning stability conditions without support wheel

An attempt to use the vertical component of the plough traction resistance to load the tractor driving wheels led to the creation of ploughing units according to the “push-pull” diagram. In most of them, in the process of movement, the supporting wheel of the front plough, moving along the bottom of the furrow, limits the depth of ploughing. In addition, it plays the role of an element that copies the trajectory of the previous adjacent pass of the ploughing unit. In the soil conditions where it is problematic to ensure the bottom of the furrow is free from lumps of soil, the front plough support wheel is placed outside the furrow. In this case, the front plough is joined to the tractor without the possibility of their mutual agility in the horizontal plane (that is, rigidly). This article discusses the conditions for operating a front plough without a supporting wheel. With this design, the ploughing depth limiter is an adjustable limiter chain. It is joined to the tractor frame at one end and the other end to one of the lower links of the tractor front hitch linkage system (TFHLS). The total vertical additional load of the tractor’s front axle was taken as an estimated indicator of the front plough functioning. It is carried out by forces acting in the central and lower links and the restrictive chain of TFHLS. Calculations have established that the effect of the ploughing depth and the front plough specific resistance on the total vertical loading of the tractor front axle is less significant than the effect of the plough weight and its operating width. To ensure the structural reliability of elements of TFHLS, the inclination angle of its lower links must be in the range of 0–5°. The inclination angle of the central link of this system can vary between 25–30°.