A successful method of rise of the road-headers resource can be provided with the destruction process end optimization on the basis of mathematical models[2]. Existent methods of optimization, for example [3], do not consider the backlashes as a variable in designing in the suspension acting unit system. At the same time, in the real construction of selective action headers in joints and guides of arrow movement there are the backlashes which can run up to 1 – 5 mm under the maximal attrition.
It can result in the decline of the combine resource due to the shock loading at backlashes rerun. Therefore further research on the analysis of backlashes influence on dynamic header loading is necessary.
According to the standard classification of oscillatory systems and processes at the working process roadheader represents independent system with final number of freedom degrees, which define a dynamic condition of system a combine-end during any fixed moment of time. Feature of such systems is an opportunity of self-excitation and the maintenance into them fluctuations due to an internal energy source with not oscillatory nature, for example, the engine, and receipt of energy is adjusted by movement of the combine which is carrying out working process of branch and a unloading of a mineral (breed). The established self-oscillations parameters are defined substantially by nonlinear properties of system. Most essential of them in system combine-face is a nonlinear kinetic characteristic of combine foot friction on the conveyor guides and nonlinearity of sharply variable resistance forces formed on working tools of acting units, cooperating with a casual damage characteristics massif.
Inconstancy of resistance forces on acting and traction units and presence of elastic communications in structure of combine power systems are serve as the reasons of formation in complex dynamic processessystem. Feature of these processes - interrelation between parameters shave forming and forces corresponding them which can be named external, and parameters of oscillatory processes in independent system a combine-end.Combine power systems fluctuations and the dynamic loadings caused by them, in turn, depend on a spectrum of resistance forces on acting units, dynamic parameters of power systems and their interaction among themselves and with an environment - unit with a destroyed massif, and the engine - with a network of electrosupply.
The aim of work is to determine:
- influence of parameters of the system of suspension acting unit on road-headers loading.
- influence of parameters of the system of suspension of acting unit on the shave forming
Solving the problem can be made through mathematical modeling of working process of road-header acting unit. The mathematical modeling enables, to some extend, to simplify researches and lower it cost. Last it is especially important in the present economic situation. Its similarity to the object-original, that is to the real process of mountain destruction, is above all requirements to the model.
Only on condition of adequacy the work performances of model observance can be considered as grounded and objective and the analysis of these results can be done with subsequent conclusions.A backlashes in the suspension system namely in guides of arrow movement is accepted as variable. In the process of work the MathCad program is used, due to which dependence of accumulated damage from the size of backlashes is determined. MathCad allows to conduct a number of researches with data varying for the receive more exact and clear picture.
Picture1.-Computation model
A computation model (pict.1) is an acting unit as the joint fastened beam, the beam, with the attached concentrated mass. At cooperation of arrow with a mountain breed work of road-headers is accompanied by dynamic processes resulting in vibrations of acting unit in guides of arrow movement, that in it’s turn entails the increase of backlashes.