In order to reduce the greenhouse effect caused by CO2 emissions, a lot of car manufacturers are developing battery electric vehicles (BEVs). Almost all of these vehicles have a traditional powertrain layout with the drive unit located in the car body. However, in recent years, a new technology called in-wheel motors has appeared. It significantly improves handling and manoeuvrability of vehicles but it also presents a challenge for both researchers and manufacturers. Since the motors are fitted into a limited space, they must provide high torque and high efficiency. When a reducer is used, the amount of torque needed is decreased several times, hence the overall dimensions of the motor are reduced. This paper studies a number of issues such as the basic concepts of the in-wheel hub drive systems, traction balance, preliminary gear ratio and possible design solutions for reducers used in in-wheel hub drive units. Characteristics of single-stage planetary and cycloidal reducers are analysed in detail. The results show that planetary reducers have an advantage if a lower gear ratio is needed.

High-precision drives are essential for ensuring accuracy and repeatability in positioning systems within robotics and industrial automation. Among these, cycloidal reducers are widely utilized due to their ability to deliver a high transmission ratio alongside high power density. However, compact designs often face challenges such as elevated operating temperatures caused by limited heat dissipation areas, making it crucial to assess thermal stability within the design process. While engineering practice typically determines the thermal stability of gear drives using ISO/TR 14179-2:2001, no specific methodologies have yet been developed for cycloidal reducers. To address this gap, this paper presents a novel mathematical model fine-tuned to quantify power dissipation and predict lubricant stabilization temperatures under varying operating conditions. The model employs a global energy balance approach, correlating total power losses with the heat dissipated from the reducer to the environment. Moreover, in this study, an experimental campaign was carried out to monitor the thermal behaviour of a cycloidal reducer under various operating conditions in terms of speed and transmitted torque. This was achieved through the analysis of images collected with an infrared thermal camera, both during the transient phase and under steady-state thermal conditions. The results demonstrate good alignment with experimental findings, although further refinements are required to develop specialized tools for cycloidal drives. Additional contributions of the present paper include the understanding of the time required to achieve thermal stability, as well as insights into heat generation and propagation. Beyond advancing scientific knowledge, this work also provides valuable practical guidance for engineering applications.

Belt conveyors play a very important role in the continuous transport o f bulk and piece material, especially in the mining industry. However, the use o f belt conveyors results in high electricity consumption. A reduction in the power consumption can be achieved by adjusting the speed o f the belt conveyor to match the material flow. However, inappropriate and frequent speed changes can cause serious damage to the conveyor elements. This paper presents a procedure for adjusting the belt conveyor speed to match the profile o f the material on the belt, as well as a detailed procedure for determining the time needed to accelerate/decelerate the belt conveyor. The research was performed on an actual 640 m long belt conveyor used for transport o f overburden at the surface mine Drmno (Serbia). The simulation results show that the speed regulation is completely justified because the conveyor operated at speeds lower than nominal throughout the testing.

There is intensive rolling and sliding between the meshing elements of a cycloidal reducer, whereby a significant amount of mechanical energy is converted into heat and absorbed by the lubricant. In order to stabilize the temperature of the lubricant, it is necessary to achieve thermal equilibrium, i.e. the amount of heat dissipated should equal the amount of heat generated. A complex task of determining the equilibrium temperature of a lubricant generally involves theoretical analysis, numerical calculation, computational simulations and experimental testing. The aim of this paper is to develop a model to predict the amount of heat dissipated from the outer surface of the housing as well as the equilibrium temperature of the lubricant. The model is based on the basic laws of thermodynamics, while the computational simulation is performed for an actual cycloidal reducer in the Matlab software package. The simulation results show changes in the equilibrium temperature in relation to: the coefficient of heat transfer from the lubricant to the inner wall of the housing, ambient air velocity, wall thickness and housing material.