1、October 2011 Translation by DIN-Sprachendienst.English price group 6No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS
2、 21.100.20!$t|*“1818907www.din.deDThis supplement provides information relating to DIN ISO 76, but does not contain any additional specifications.DIN ISO 76 Supplement 2Rolling bearings Static load ratings Supplement 2: Load ratings for hybrid bearingsEnglish translation of DIN ISO 76 Beiblatt 2:201
3、1-10Wlzlager Statische Tragzahlen Beiblatt 2: Tragzahlen fr Hybrid-WlzlagerEnglische bersetzung von DIN ISO 76 Beiblatt 2:2011-10Roulements Charges statiques de base Supplment 2: Charges de base pour roulements hybridesTraduction anglaise de DIN ISO 76 Beiblatt 2:2011-10www.beuth.deIn case of doubt,
4、 the German-language original shall be considered authoritative.Document comprises 8 pages10.11 DIN ISO 76 Suppl 2:2011-10 A comma is used as the decimal marker. Content Page Foreword. 3 1 Scope 4 2 Symbols . 4 3 Static load rating . 5 3.1 Ball bearings 5 3.1.1 Basic static radial load rating. 5 3.1
5、.2 Basic static axial load rating 5 3.2 Roller bearings 6 3.2.1 Basic static radial load rating. 6 3.2.2 Basic static axial load rating 6 Annex A (informative) Calculation of the Hertzian parameters for point contact . 7 Bibliography . 8 2 DIN ISO 76 Suppl 2:2011-10 Foreword This standard has been p
6、repared by Normenausschuss Wlz- und Gleitlager (Rolling Bearings and Plain Bearings Standards Committee), Working Committee NA 118-01-08 AA Tragzahlen und Lebensdauer. Hybrid bearings are rolling bearings with raceways consisting of commonly used rolling bearing steel and rolling elements consisting
7、 of ceramic, usually silicon nitride. Due to the higher modulus of elasticity of the ceramic rolling elements, hybrid bearings have a noticeably smaller contact ellipse at the same load than rolling bearings with rolling elements of steel. This will lead to higher contact stresses at the same load a
8、nd therefore to a reduced static load-carrying ability. 3 DIN ISO 76 Suppl 2:2011-10 1 Scope This document gives guidelines to calculate the static load ratings for hybrid bearings with bearing rings made of contemporary, commonly used, high quality hardened bearing steel, in accordance with good ma
9、nufacturing practice and rolling elements made of ceramic, usually silicon nitride (Si3N4) in contemporary, commonly used material and manufacturing quality. It contains no normative provisions. When using hybrid bearings the reduced static load ratings and the recommendations for the static safety
10、factor according to DIN ISO 76 in comparison to conventional rolling bearings shall be observed. 2 Symbols a0C basic static axial load rating, in newtons (N) r0C basic static radial load rating, in newtons (N) pwD pitch diameter of ball or roller set, in millimetres (mm) wD nominal ball diameter, in
11、 millimetres (mm) weD roller diameter applicable in the calculation of load ratings, in millimetres (mm) E modulus of elasticity, in newtons per square millimetre (N/mm2) )(E complete elliptic integral of the second kind )(F relative curvature difference 0f factor for calculation of basic static loa
12、d rating i number of rows of rolling elements )(K complete elliptic integral of the first kind weL effective roller length applicable in the calculation of load ratings, in millimetres (mm) er cross-sectional raceway groove radius of outer ring or housing washer, in millimetres (mm) ir cross-section
13、al raceway groove radius of inner ring or shaft washer, in millimetres (mm) Z number of rolling elements in a single-row bearing; number of rolling elements per row of a multi-row bearing with the same number of rolling elements per row nominal contact angle, in degrees () auxiliary parameter, pww/c
14、os DD = E Poissons rate curvature sum, in millimetres to the power of minus one (mm1) angular position of rolling element, in degrees () ratio of semi-major to semi-minor axis of the contact ellipse 4 DIN ISO 76 Suppl 2:2011-10 3 Static load rating 3.1 Ball bearings 3.1.1 Basic static radial load ra
15、ting The basic static radial load rating for a radial ball bearing with a ceramic ball set is given by the equation: cos2w0r0= DZifC (1) with e,0i,00,min fff = (2) and ()2iwiii,0212679,1+=rDEf (3) ()2eweee,0212679,1+=rDEf(4) The calculation of the Hertzian parameters and )(E is described in Annex A.
16、 3.1.2 Basic static axial load rating The basic static axial load rating for a thrust ball bearing with a ceramic ball set is given by the equation: sin2w0a0= DZfC (5) with e,0i,00,min fff = (6) and ()2iwiii,0212396,8+=rDEf (7) 5 DIN ISO 76 Suppl 2:2011-10 ()2eweee,0212396,8+=rDEf (8) where Z is the
17、 number of balls carrying load in one direction. The calculation of the Hertzian parameters and )(E is described in Annex A. 3.2 Roller bearings 3.2.1 Basic static radial load rating The basic static radial load rating for a radial roller bearing with a ceramic roller set is given by the equation: c
18、oscos1975,36wewepwwer0= DLZiDDC (9) 3.2.2 Basic static axial load rating The basic static axial load rating for a thrust roller bearing with a ceramic roller set is given by the equation: sincos1879,184wewepwwea0= DLZDDC (10) where Z is the number of rollers carrying load in one direction. 6 DIN ISO
19、 76 Suppl 2:2011-10 Annex A (informative) Calculation of the Hertzian parameters for point contact The ratio of semi-minor to semi-m ajor axis of the contact ellipse, , can be derived iteratively from the following equation: 0)(1)()(1212= FEK(A.1) The complete elliptic integral of the first kind, )(
20、K , is ()=202122dsin111)( K (A.2) and the complete elliptic integral of the second kind, )(E , is ()=202122dsin111)( E (A.3) The curvature sum of the inner ring shaft washer raceway contact is +=iwwi2122rDD (A.4) and the curvature sum of the outer ring housing washer raceway contact is +=ewwe2122rDD
21、 (A.5) The relative curvature difference of the inner ring shaft washer raceway contact is ()iwiwi21221rDrDF+= (A.6) and the relative curvature difference of the outer ring housing washer raceway contact is ()ewewe21221rDrDF+= (A.7) 7 DIN ISO 76 Suppl 2:2011-10 8 Bibliography DIN ISO 76, Rolling bea
22、rings Static load ratings DIN ISO 281 Supplement 5, Rolling bearings Dynamic load ratings and rating life Supplement 5: Load ratings for hybrid bearings ISO 3290-2, Rolling bearings Balls Part 2: Ceramic balls ISO 26602, Fine ceramics (advanced ceramics, advanced technical ceramics) Silicon nitride materials for rolling bearing balls
