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W. Ostapski

Analysis of the stress state in the harmonic drive generator-flexspline system in relation to selected structural parameters and manufacturing deviations

In the paper, the problem of failure of the elastic bearing supporting the generator in a harmonic drive is presented. To analyse the cause of the failure, material investigations as well as simulations of the stress state in the bearing versus manufacturing deviations and fits between the bearing and the generator cam have been carried out. Studies on the stress state in the flexpline have also been conducted in dependence of such technological deviations and generator bearing-flexspline fits for the classical, short, and ultra-short version of the harmonic drive with different heights of the bottom. The simulations have been realised on a mathematical model based on analytical relationships and a 3D model with the aid of FEM.

Open access

W. Chomczyk, W. Ostapski, J. Piotrowski and T. Tataj

Abstract

The contents are concerned with a concept of an oilless and frictionless compressor operating without dead movement and having functional parameters superior to compressors of renowned manufacturers. The concept is based on patents No. 68220, 83060, P377851 by W. Chomczyk and patents P394072, P385733 by W. Chomczyk, W. Ostapski and J. Piotrowski. The proposed design of an oilless compressor ensures volumetric efficiency higher than that encountered in conventional compressors. It also generates pure compressed medium without necessity of filtering from oil particles, which is especially desired in food, pharmaceutical, medical, fragrance, chemical and automation industry.

Open access

W. Ostapski, T. Wierzchoń, J. Rudnicki and S. Dowkontt

Abstract

In Ostapski et al., Bull. Pol. Ac.: Tech 65(1), 93-105 (2017), doi: 10.1515/bpasts-2017-0012, an analysis of tribological wear of an assembly composed of cylinder liner and piston rings in a piston aircraft engine was presented. In place of the previously used technology of gas nitriding of the cylinder liner (made out of 38CrAlMo6-10 steel), formation of multi-component or composite layers by nitriding in plasma discharge environment was proposed. Also, a modification of the previously used chromium coating of the piston rings by plasma nitriding was proposed. A study on the structure and properties of surface layer diffusion manufactured by utilizing the phenomenon of cathode sputtering was carried out. Wear resistance tests were performed on a specially designed bench, with the use of isotope markers. Verification of each of the friction couples was based on using the wear of the ring as a function of the distance trip, and the roughness of the cylinder liner and ring. This note corrects flaws in illustrations published in the original paper.

Open access

W. Ostapski, T. Wierzchoń, J. Rudnicki and S. Dowkontt

Abstract

The paper presents an analysis of tribological wear of an assembly composed of cylinder liner and piston rings in a piston aircraft engine. In place of the previously used technology of gas nitriding of the cylinder liner (made out of 38CrAlMo6‒10 steel), formation of multi-component or composite layers by nitriding in plasma discharge environment was proposed. Also, a modification of the previously used chromium coating of the piston rings by plasma nitriding was proposed. A study on the structure and properties of surface layer diffusion manufactured by utilizing the phenomenon of cathode sputtering was carried out. Wear resistance tests were performed on a specially designed bench, with the use of isotope markers. Verification of each of the friction couples was based on using the wear of the ring as a function of the distance trip, and the roughness of the cylinder liner and ring.

Open access

W. Ostapski, A. Aromiński and S. Dowkontt

Abstract

The results of torsional shaft vibration bench tests for a prototype aircraft propeller speed reduction unit are presented in this paper. The study was conducted as a function of engine speed and lubrication conditions. 3D model of the propeller speed reduction unit was developed. By using the finite element method, normal modes frequencies were defined. The simulation was conducted both unloaded and loaded under nominal power conditions.