Simulation tests of peripheral friction brake used in agricultural machinery shafts
2020
Borawski, A., Bialystok Univ. of Technology (Poland) | Mieczkowski, G., Bialystok Univ. of Technology (Poland) | Szpica, D., Bialystok Univ. of Technology (Poland)
Shafts are commonly used parts in agricultural machinery. They are responsible for transmitting the torque from the power source to the receiver, which can be, e.g. a mower blade, hydraulic pump or something completely different. In the agricultural industry, where the operator is very often near a rotating part, it is important to have the ability to quickly stop the rotating shaft. This has a direct impact on work safety. Therefore, the health or even life of both the operator and third parties nearby may depend on the proper functioning of the braking system. A characteristic feature of all friction brakes is their heating up during operation. High rotational speeds of shafts combined with the need to quickly stop the rotational element can lead to the generation of very high temperatures in the friction node. Overheating the brake can lead to the so-called fading phenomenon, which reduces the value of the friction coefficient practically to zero. The purpose of the work was to develop a mathematical model of the agricultural machine shaft breaking process and check how the initial speed affects the heating of friction steam. In this work, a mathematical model of a typical peripheral brake was developed, and simulation tests of the shaft braking process from different initial speeds based on it were performed. The CAD model of the brake and the finite element method were used to determine temperature profiles. It was also assumed that the inertia resulting from the non-zero mass of the system is constant for all cases. The stopping time was also the same for each case. The obtained results allow to assess the dependence of heating on the initial rotation speed of the shaft, and the developed model can be extremely helpful at the design stage of agricultural machinery.
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