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The presented paper deals with comparison of spur gears classical and modern hardening process of the bending fatigue properties. It concerned particularly the hardened surface of the tooth flank using optical source of electromagnetic radiation. The results of fatigue tests were obtained on a servo-hydraulic testing machine LFV 100 kN made by walter+bai ag. These tests were defined by the standard ISO 6336 as method B, when testing is carried out under reference conditions close to the real operation. Comparison of test samples is also carried out on the basic of the achieved local hardness and hardened layer thickness in the tooth root, which is an initiation of fatigue crack.

At present, the unevenness of the cardan shaft, more precisely the Hook joint, can be described mathematically. This formulation of the non-uniformity is based on the knowledge of the angular velocity of the drive and driven shaft. However, there is no real understanding of how the non-uniformity affects the behavior of the drivetrain, in particular the vibration of the drivetrain. This paper describes an experiment that may shed light on this problem. Another contribution of this research could be to investigate how the length of the cardan shaft affects drivetrain vibration.

In the vast majority of technical applications, there is a necessity to transmit the torque from drive to driven machine together with the demand to overcome great distance between given devices. One of the solutions of this problem is the use of a cardan shaft. Operations of connecting shaft and drivetrain are accompanied by oscillations negatively influencing the driver comfort. Main subject of this article is the measurement of vibrations on different parts of a heavy truck and its evaluation by FFT analysis. Measurements are performed with two kinds of suspension bushing which are compared with to each other. Based on the previous measuring, influence of cardan shaft length was also investigated. First of all, dependency on the length of the cardan shaft on deflection angles for V arrangement was evaluated by analytical method. The theoretical introduction is followed by research of eigen frequency depending on the length of the cardan shaft. The results obtained by modal analysis in FEM are verified by experimental modal analysis [1].

This article deals with testing of fatigue properties of hardened gears at bending. These tests are defined by the standard ISO 6336 - method B, when testing is carried out under reference conditions close to the real operation. This type of testing may be helpful to evaluate the influence of new materials, design parameters, production technology, or the effects of surface finishing. The first part of this article deals with the theory of fatigue testing methodology using modified stair-case method and characteristics of the testing machine. The second part of the paper is devoted to the characteristics of the experimental material and the results achieved. The case hardened steel gears alloyed by Cr-Ni-Mo were selected for the experiment. Hardened gears were subjected to local hardness measurement and subsequently the bending fatigue tests were performed. Ruptured samples were analyzed using a scanning electron microscope. The local bending stress was determined using the modified computational model based on the ISO 6336 standard methodology. The focus of this work consisted in evaluation of the influence of the filler root surface treatment on fatigue limit at bending on the basis of the realized experiments and their confrontation with the equivalents specified in the standards ISO 6336 and ČSN 01 4686.