W artykule jest przedstawione badanie wpływu korekcji styku na bieżniach głównych łożyska baryłkowego na tarcie i naciski kontaktowe przy różnych obciążeniach i dwóch różnych rodzajach korekcji. Metoda obliczeń jest opisana w jednym z poprzednich artykułów autora. Uzyskane charakterystyki momentu tarcia i nacisków kontaktowych służą do określenia optymalnych wartości parametrów mikrogeometrycznych. Zaprezentowana na jednym przykładzie metoda postępowania może być zastosowana do konstruowania dowolnego łożyska baryłkowego dwurzędowego. Analiaza wyników obliczeń wykazała, że przy obciążeniach małych i średnich (P/C<0,2) wystarcza zastosowanie jednołukowej korekcji wałeczków. Przy większych obciążeniach pożądana jest korekcja dwułukowa ze względu na spiętrzenia nacisków kontaktowych.
The present article is the fourth of a series by this author concerning the microgeometry of roller bearings.published in "Tribology". The previous had the following titles "Purpose and possibilities of the use of correction in roller bearings" ,"The Method of analysis of pressures and friction in roller bearings in aspect of contact correction" and "The effect of microgeometry on running parameters of taper roller bearings". In order to investigate the effect of the microgeometrical dimensions of the spherical roller bearings on power losses and contact pressures, the author has written a special computer program. It is base on the methodology presented in paper(L11). In the program, equations of balance are solved first. Then, contact pressures the skew of the roller and the moment of frictionof the bearing for the pre-set dimensions and load are computed. One significant checking parameter is the roller skew self-stabilisation angle.Its absolute value shows whether the roller presses against the side flange during the rolling(L8). The operation of a bearing is considered correct if the rollers are in the state of self-stabilisation without any contact with the side flange (L.3). In such a case, the microgeometry of the spherical roller bearing resolves itself to the form of adhesion of the roller profile to the inner and outer ring profile. This form results from the correction of an appropriate contact. In practice, two kinds of correction of spherical roller bearings are possible (FIG.1a) and two-arc correction (FIG. 1b). In the analyses made so far, the attention was paid only to the importance of correction for the uniform distribution of pressures in the contact, and not to the resistance to motion of the bearing. The aim of the calculations presented herein is to investigate the effect of the spherical roller bearing microgeometry on the contact capacity and the resistance to motion. These properties of the bearings are practically defined by two parameters: the maximum contact pressures and the moment of friction. The sample calculations refer to one type bearing only, namely 22316. Two levels of the relative load of the bearing was assumed P/C=0.1 (average load) and P/C = 0.35 (large load).The calculation results are presented in the form of graphs which show the characteristics of the greatest unit pressures at the contact of the roller and the rings p(max.w) and p (max.z) as a function of the radius R(BW), the characteristics of the self-stabilisation angle Θ 0 for the loaded rollers and the characteristics of the moment of friction of the bearing. Owing to these graphs the most favourable values of R(BW) can be selected; the minimum of the moment of friction and the smallest values of pressures should be aimed at; at the same time, the self-stabilisation angles Θ 0 of the loaded rollers should be kept within -0.006rad - +0.006rad. An analysis of the results of the computer computations has shown that spherical roller bearings with the rollers made without two-arc correction can be satisfactority used under small and medium loads (P/C<0.2). By using the selected dimensions R(B) and R(BW),the concentraction of stresses can be avoided and a satisfactory compromise beteween the minimisation of the resistance to motion and the minimisation of contact stresses achieved. If the relative load of the bearing is geater than 0.2, the concentration of stresses is formed, first of all at the contact of the roller and the outer ring (due to the greater adhesion coefficient). In this situation, the correction of the rollers is necessary. Analyses have proved that the two-arc correction of the parameters conformant with the results of the work is effective (L.7). The same radii, R(B) and R(BW), which turned out to be the most favourable in the case of the roller made without two-arc correction can be used here as the main radii of the lateral generatrix of the roller and the race of the outer ring. The method of finding the most favourable dimensions of the bearing of reference number 22316 can be used for any type and size of a spherical roller bearing. Thus, it is a practical method for the engineering shaping of the working surfaces of double -row spherical roller bearings.