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Warianty tytułu
The effect of microgeometry on running parameters of taper roller bearnings
Języki publikacji
Abstrakty
W artykule przedstawiono badanie wpływu korekcji i geometrii styku na biezni pomocniczej łożyska stożkowego na tarcie i naciski kontaktowe przy różnej makrogeometrii i różnych obciążeniach. Metoda obliczeń jest opisana w poprzednim artykule autora. Charakterystyki momentu tarcia i nacisków kontaktowych służą określeniu optymalnych wartości parametrów mikrogeometrycznych. Są przedstawione zależności tych optymalnych parametrów od makrogeometrii łożyska. Podane zalecenia mogą być bezpośrednio wykorzystane do projektowania kształtu powierzchni roboczych łożyska stożkowego, charakteryzującego się zmniejszonymi oporami ruchu i większą prędkością graniczną.
The following work represents the continuation of the former articles written by the same author: "Purposes and Possibilities of the Use of Correction in Roller Bearings" and "The Method of Analysis of Pressures and Friction in Roller Bearings from the Aspect of the Contact Correction". .In order to do research work on the influence of microgeometrical dimensions (beta,hi, ho, hw, delta, Rk) on friction lisses and contact pressure the author worked out the computer programme based on method shown in (L.6). In the programme, equations of equilibrium are solved first, then running parameters are calculated (primarily the moment of friction of a bearing and contact pressures) for given bearing dimensions and axial load Fa. The choice of correction of main bearing races and main surface of roller. Research was carried out for ten bearing sizes. For each size, 306 correction combinations were determined. For each combination calculations in the range of angle beta from (βn - 4') to (βn + 4') ware made to obtain the smallest moment M(T) value. Relative load was assumed at P/C =0,35 level. In all series with a contact angle α less then 17° the smallest values of M(T) are achieved at the correction system that is hi=hw>0 ho=0. Only in the 313 series (α=28°48'39") the smallest values of M(T) are achieved at the correction system: hi=hw>0, ho(…)2hi.The proper correction value depends and its dimensional proportions. Therefore, the choice of correction value was solved by means of non-dimensional method for fictitious bearings with different macrogeometry. The results of these calculations are illustrated in DRAWING 4. The characteristics of the most favourable correction values depending on bearing macrogeometry is shown in DRAWING 5. The choice of angle β. Drawing 6 present an example of characteristics of a moment of friction for a certain macrogeometrical case. The most favourable value β is about 1°59'55". Taking working tolerance into consideration, it was assumed that the tolerance range of angle β should lie between -4" and +26". As result of the calculations of the friction moment for other variants of macrogeometry, depedence of recommended angle β deviations on quotient Lw/Dw was determined, which is shown in DRAWING 7. The choice of angle δ an radius Rk. The studies of the influence of these parameters on pressure in a roller 's contact with a side flange and on the friction moment of a bearing were jointly conducted by means of a non-dimensional method. One of the resultant diagrams is demonstrated in DRAWING 8. On exceeding a certain value of Rk the moment of friction rapidly rises as a result of extension of the contact area, which starts on the edge of the roller end. This causes an increase in friction force and makes the formation of an oil film difficult. The successive curves attributed to the increasing values of an angle δ are displaced downwards and to the left. The value of the angle is compromising due to the friction and contact pressures and it is enclosed in the range of 89°40'÷89°45'. The minimum moment of friction occurs at Rk=0,95÷0,96 value. Owing to the analogus calculations made for others macrogeometrical variants, the dependence of the most favoruable values δ and Rk on macrogeometry parameters was obtained. It is shown in DRAWING 10 in a form of diagrams. At the end an example of the correction choice is presented. On comparing the results with the recommendation stated in work (L.2), it was assumed that there was a little difference between them. On the other hand, using the above described method one can divide the recommended in (L.2) sum of correction between a bearing roller and bearing rings.
Słowa kluczowe
Czasopismo
Rocznik
Tom
Strony
90--110
Opis fizyczny
bibliogr. 7 poz., tab., wykr.
Twórcy
autor
- Katedra Techniki Grzewczej i Wentylacyjnej Politechniki Łodzkiej
Bibliografia
Typ dokumentu
Bibliografia
Identyfikator YADDA
bwmeta1.element.baztech-article-BPS1-0006-0022
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