SHRNUTÍČlánek popisuje mechanismy pro realizaci únavových zkoušek ozubených kol na pulsátoru, které vedou k získání pravděpodobnostního průběhu meze únavy v ohybu. Na základě realizovaných experimentů je navržena metodika pro návrh a realizaci tohoto typu zkoušek. Pozornost je rovněž věnována konstrukci zkušebních vzorků a tvaru zkušebních čelistí. KLÍČOVÁ SLOVA: METODIKA, PULZÁTOROVÉ ÚNAVOVÉ ZKOUŠKY, STUPŇOVITÁ METODA, PRAVDĚPODOBNOSTNÍ PRŮBĚH MEZE ÚNAVY V OHYBU ABSTRACTThis article describes the mechanisms for performing fatigue tests on gears using a single tooth bending test, which enables determination of the probability of fatigue limit in bending. The testing methodology is proposed based on experiments carried out. Attention is also paid to the design of the test specimen and shape of the jaws.

SHRNUTÍČlánek dává návod, jak statisticky zpracovat výsledky experimentálních zkoušek ozubených kol na pulsátoru. Za předpokladu zkoušení materiálu podle metody stair-case jsou uvedeny algoritmy, jak vyhodnotit pravděpodobnostní průběh meze únavy v ohybu. Vyhodnocení je demonstrováno na reálných výsledcích únavových zkoušek. KLÍČOVÁ SLOVA: METODIKA, PULZÁTOROVÉ ZKOUŠKY, ÚNAVA, STUPŇOVITÁ METODA, PRAVDĚPODOBNOSTNÍ PRŮBĚH MEZE ÚNAVY V OHYBU ABSTRACTThis article provides guidelines on how to statistically treat the results from single tooth fatigue tests. Assuming the methodology for testing is followed, algorithms are presented here to evaluate the probability plot of the fatigue limit in bending. The evaluation is demonstrated using actual results from fatigue tests.

Shrnutí Članek se zabyva navrhem dimenzovani ozubeni pro různe typy automobilnich diferencialů a děličů momentů. V navrženem postupu jsou použity nejnovějši vypočtove postupy podle norem ISO a DIN. Do vypočtu jsou aplikovana hypoteticka spektra provozniho zatiženi, ktera jsou odvozena od vlastnich měřeni.

A modification of an involute gearing is presented by a modification of an involute and a longitudinal modification along the face width. In the contribution both of the modifications are presented and theoretical and practical methods for determination of their parameters are shown. Experimental methods of setting up of input data for design of modifications are brought in then. These data are prepared on the basis of measuring of deformations of gearwheels bodies, shafts and shafts supports. An attention is given to the influence on a size and position of a zone of contact of meshing teeth. A separate part deals with the appreciation of an influence of modification on a size of a noise and vibrations of involute gears. As far as a loading capacity of modified involute gearings, the attention is first given to the loading capacity in a contact stress between teeth faces. The comparison is made between loading capacity of an involute gearing with no modification and a gearing modified by various types of modifications. This comparison is made both by using a FEM and by experiment. Experiment is based on lifetime test of these gearing.

This contribution deals with the methodology of a lifetime calculation for gearings of automobile differentials in bending and a contact. Basis of a calculation is an operating loading spectrum whose determination for a differential is very difficult. In this contribution a procedure for a determination of a hypothetic loading spectrum by the mathematical formula with an exploitation of an experiment is published. A calculation of a contact stress and a bending stress in the root is also made by using modified techniques in accordance with appropriate standards. An assessment of gearing service life is based on a calculation of an intensity of damages using Haibach's theory of a cumulating of damages. But there's no point in to use this method for differential gearing. The new procedure is designed -this new procedure evaluates loading capacity of gearing by a utilization of an ultimate or reliable recommended safety factors which are subjected to the endurance limit.