The power transmission stability and efficiency of V-belts

Abstract

Abstract. The V-belt drive is a rather popular, widely used form of power transmission in agricultural and food industry engineering. At the same time, its stability, the lifetime of V-belt is influenced by several environmental factors, namely in the food industry by the contamination affecting the belt sides, the ambient temperature, humidity and the occasionally aggressive (acidic, alkaline air, air saturated with gases, etc.) medium. In the case of agricultural machinery, the vibration caused by uncertainly oriented pulleys with bearing in different plate structures (often being shaken in the fields) as well as alignment adjustment inaccuracies jeopardize the reliability of the parameters of the drive. Furthermore, the efficiency is determined by several factors together: the slippage occurring during drive transmission, the hysteresis loss resulting from the external and internal friction occurring with the belt entering and exiting the pulley. Experimental equipment and calculation methods were developed to determine the dynamics of temperature increase generated by the belt and pulley relationship. The temperature generated in the V-belt was measured as a function of pretension, pulley diameter and bending frequency. The so-called damping factor characterizing the contact with the pulley (the external friction when entering and exiting the groove) and the hysteresis loss (inner friction) are also determined. On the basis of the damping factor (≈ 400 Ns/m 2 ) of the Vbelt involved in the experiments the other losses (Poth) occurring from the pulley-V-belt contact and internal friction may be estimated. The drive parameters may be optimized with the mathematical model describing the effect of the pulley diameter and belt frequency on the increase in temperature.A standardized calculation method as well as design factors valid for the properly adjusted drive and normal operating conditions determined through empirical and laboratory experiments are used for the sizing of V-belt drives. The lifetime of V-belt drives designed in this way, used in extreme conditions typical of agricultural machinery will not be appropriate and will not provide clear, predictable information for maintenance planning. In such cases the results of our own many lifetime tests conducted in the given circumstances can be safely relied on.The agricultural harvesting machines are large plate-body self-propelled structures on which most of the power supply of the (threshing, cleaning, moving, etc.) machine units handling the crop is realized via belt drives. The distance and angular displacement of the axes involved in the drive can vary within wide limits. The misalignment and angular displacement of the pulleys can be the result of installation instability -due to the plate structure -and the deformation of the plate structure occurring during the * Corresponding author. Phone: +36-28-522080, E-mail: gardonyi.peter@gek.szie.hu 1 Institute of Mechanics and Machinery, Faculty of Mechanical Engineering, Szent István University, Páter K...

Advanced Calculation Model of V-Belt Temperature Field

“…High temperature fault of V-belt is a common fault in transmission system of harvester. A higher belt temperature leads to the degradation of polymer molecule chains to the aging of the rubber, thereby significantly affecting the service life of the V-belt [33]. A rule of thumb is that an increase of 18 °F in internal belt temperature will reduce the belt life by 50 % [34], [35].…”