A comparative study of a cycloidal gearbox working with a different kind of bearings is presented in the article. Two kinds of the bearings used in the cycloidal gearbox are taken into consideration: sleeves and needle bearings. The theoretical efficiency calculation for both types of the bearing was compared with experimental results. The experiment was performed on a one-stage cycloidal gearbox designed, calculated, and manufactured during the research. The test was made under different working conditions, input speeds, and the braking torques. The results show an increase in the efficiency for the needle bearings compared to sleeves. The value of the efficiency is strictly connected with the braking torque of the gearbox as well as with the velocity. The article shows a very good correlation between calculated efficiency and the efficiency determined during the tests.

The article discusses the problem of a torque ripple on the output shaft of a cycloidal gearbox. To investigate the phenomenon, numerical simulations were performed and compared with the experimental results. Simulations were performed with multibody dynamic software—one with rigid and second with flexible elements. The dynamic model of the gearbox for the determination of the amplitude of the torque change was introduced, where the model utilizes periodical change of the stiffness of gear components as well as geometrical parameters, which are the results of machining and assembly tolerances. The test was made on a gearbox that was calculated, designed, and tested by the authors of the article. To perform the test, a test bench was built. The bench included electric motors, torque meters, and a control application.

The article presents a method for diagnosing cycloidal gear damage on a laboratory stand. The damage was simulated by removing the sliding sleeves from two adjacent external pins of the cycloidal gearbox. Damage to the sliding sleeves may occur under operating conditions and can lead to the destruction of the gear unit. Hence, early detection is essential. Signals from torque sensors, rotational speed sensors and vibration acceleration sensors of input and output shafts for various rotational speeds and transmission loads were recorded. The frequency analysis of these signals was carried out. Due to the fluctuation of the rotational speed, the frequency spectrum gives an approximate picture and is not useful in detecting this type of damage. The statistical characteristics of the signal were determined. However, only statistical moments of higher orders, such as kurtosis, are sensitive to the tested damage. Therefore, the use of multifractal analysis of the vibration signal using the wavelet leader method (WLMF) was considered. Then log-cumulants of the multifractal spectrum were selected as the new signal features.

The paper presents a study of the impact of oil mineral-based and synthetic-based oils on the efficiency of the single stage cycloidal gear. Experimental studies were carried out for different loads and input speeds of the gears. The reference levels were the results of theoretical calculations of efficiency of the cycloidal gear obtained at the corresponding values of loads and input speeds as in the experiment.