Investigation of front plough functioning stability conditions without support wheel

Abstract

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°.

Determining vertical oscillations of front-plow tractor without support wheel

“…One possible solution to this problem is the use of plows with a front hitch, which work under the "push" mode. Work [5] considers the working conditions of a frontal plow without a support wheel. In such a design, the plowing depth is fixed by an adjustable limiter.…”

“…Although the state of static loading of the front axle of the tractor by a front plow without a support wheel is described in detail in works [5,16], the dynamics of this process were almost not investigated.…”

“…From our review of the literature [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], it follows that most research results cannot be applied in the case of using frontal plows in a unit configured according to the "push-pull" scheme since they do not take into account the statics and dynamics of the movement of plowing units. And there are also a few scientific works that consider the operation of a plow unit with a front plow without a support wheel [5,[18][19][20][21][22]. However, in those works, it was not established under which conditions, under which stiffness and damping coefficients of the tires of the front drivers of the tractor, the additional vertical load of the front axle of the power vehicle is ensured.…”

“…The scheme of connecting the front plow to the tractor was built on the basis of study [5] and is shown in Fig. 2.…”

“…During operation of a conventional plow unit, vertical loads are distributed along the tractor axles [4]. The essence of this phenomenon is that under the influence of the force of traction resistance of the plow, which in the longitudinal-vertical plane is inclined to the horizon, the rear axle of the tractor is loaded, and the front axle, on the contrary, is unloaded [5]. To avoid this, ballast loads are usually installed on this axis.…”