1、October 2011 Translation by DIN-Sprachendienst.English price group 7No 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|)“1818906www.din.deDThis supplement provides information relating to DIN ISO 281, but does not contain any additional specifications.DIN ISO 281 Supplement 5Rolling bearings Dynamic load ratings and rating life Supplement 5: Load ratings for hybrid bearingsEnglish translation of DIN IS
3、O 281 Beiblatt 5:2011-10Wlzlager Dynamische Tragzahlen und nominelle Lebensdauer Beiblatt 5: Tragzahlen fr Hybrid-WlzlagerEnglische bersetzung von DIN ISO 281 Beiblatt 5:2011-10Roulements Charges dynamiques de base et dure nominale Supplment 5: Charges de base pour roulements hybridesTraduction angl
4、aise de DIN ISO 281 Beiblatt 5:2011-10www.beuth.deIn case of doubt, the German-language original shall be considered authoritative.Document comprises 9 pages.1110 DIN ISO 281 Suppl 5:2011-10 A comma is used as the decimal marker. Content Page Foreword. 3 1 Scope 4 2 Symbols . 4 3 Dynamic load rating
5、 5 3.1 Ball bearings 5 3.1.1 Basic dynamic radial load rating . 5 3.1.2 Basic dynamic axial load rating . 5 3.1.3 Rating factors for hybrid ball bearings .6 3.2 Roller bearings 6 3.2.1 Basic dynamic radial load rating . 6 3.2.2 Basic dynamic axial load rating . 7 3.2.3 Rating factors for hybrid roll
6、er bearings.7 4 Fatigue load limit Cu8 4.1 General . 8 4.2 Fatigue load limit of a single contact 8 4.2.1 Ball bearings 8 4.2.2 Roller bearings 8 Bibliography . 9 2 DIN ISO 281 Suppl 5:2011-10 Foreword This standard has been prepared by Normenausschuss Wlz- und Gleitlager (Rolling Bearings and Plain
7、 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 of ceramic. Due to the higher modulus of elasticity of the ceramic rollin
8、g elements hybrid bearings have a noticeably smaller contact ellipse at the same load than rolling bearings with rolling elements of steel. This will lead theoretically to a reduction of the dynamic load-carrying ability, however the smaller contact ellipse and the material combination ceramic-steel
9、 will lead to noticeably lower surface shear stress in the rolling contact, which again will lead to a higher load-carrying ability. In practice hybrid bearings show at least the same life as bearings with steel rolling elements when used in in the typical application range of hybrid bearings. There
10、fore a reduction of the dynamic load rating for hybrid bearings is not necessary. 3 DIN ISO 281 Suppl 5:2011-10 1 Scope This document gives guidelines to calculate the dynamic load ratings for hybrid bearings with bearing rings made of contemporary, commonly used, high quality hardened bearing steel
11、, in accordance with good manufacturing 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 according to DIN I
12、SO 76 Supplement 2 and the recommendations for the static safety factor according to DIN ISO 76 in comparison to conventional rolling bearings shall be observed. 2 Symbols mb rating factor for contemporary, commonly used, high quality hardened bearing steel in accordance with good manufacturing prac
13、tice, the value of which varies with bearing type and design aC basic dynamic axial load rating, in newtons (N) rC basic dynamic radial load rating, in newtons (N) uC fatigue load limit, in newtons (N) pwD pitch diameter of ball or roller set, in millimetres (mm) wD nominal ball diameter, in millime
14、tres (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) CE modulus of elasticity, ceramic, in newtons per square millimetre (N/mm2) SE modulus of elasticity, steel, in newtons per square millim
15、etre (N/mm2) )(E complete elliptic integral of the second kind cf factor which depends on the geometry of the bearing components, the accuracy to which the various components are made, and the material i number of rows of rolling elements weL effective roller length applicable in the calculation of
16、load ratings, in millimetres (mm) uQ fatigue load limit of a single contact, in newtons (N) er cross-sectional raceway groove radius of outer ring or housing washer, in millimetres (mm) ir cross-sectional raceway groove radius of inner ring or shaft washer, in millimetres (mm) Z number of rolling el
17、ements 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/cos DD = rating factor for thrust bearings rating factor for ball bearings 4 DIN ISO 281 Suppl 5:20
18、11-10 rating factor for needle and roller bearings E Poissons ratio C E, Poissons ratio, ceramic S E, Poissons ratio, steel Hu Hertzian contact stress at which the fatigue limit of the raceway material is reached, in newtons per square millimetre (N/mm2) curvature sum, in millimetres to the power of
19、 minus one (mm1) ratio of semi-major to semi-minor axis of the contact ellipse 3 Dynamic load rating 3.1 Ball bearings 3.1.1 Basic dynamic radial load rating The basic dynamic radial load rating of a hybrid ball bearing is given by the following equation: ()8,1w3/27,0cmrcos DZifbC = (1) with 1033104
20、1,0wiweei72,13/139,13,041,0wiic221104,11)1()1(22234510,27+=DrDrrrDrrf (2) 3.1.2 Basic dynamic axial load rating 3.1.2.1 Thrust ball bearings with contact angle 90 The basic dynamic axial load rating of a hybrid thrust ball bearing with contact angle 90 is given by the following equation: ()8,1w3/27,
21、0cmatansin DZfbC = (3) with 10331041,0wweei72,13/139,13,041,0wiice22111)1()1(22069632,67+=DrDrrrDrrfi (4) where Z is the number of balls carrying load in one direction. 5 DIN ISO 281 Suppl 5:2011-10 3.1.2.2 Thrust ball bearings with contact angle = 90 The basic dynamic axial load rating of a hybrid
22、thrust ball bearing with contact angle = 90 is given by the following equation: 8,1w3/2cmaDZfbC = (5) with 10331041,0wweei3,041,0wiice22122069632,67+=DrDrrrDrrfi (6) where Z is the number of balls carrying load in one direction. 3.1.3 Rating factors for hybrid ball bearings The values for the factor
23、s bm, and used in Equations (1) to (6) for the different kinds of hybrid ball bearings are given in Table 1. Table 1 Rating factors for hybrid ball bearings Bearing type mb Single row radial deep groove ball bearing Single row and double row angular contact ball bearing 1,9 0,95 Double row radial de
24、ep groove ball bearing 1,9 0,9 Thrust ball bearing 1,45 0,9 3sin1 3.2 Roller bearings 3.2.1 Basic dynamic radial load rating The basic dynamic radial load rating of a hybrid radial roller bearing is given by the following equation: ()27/29we4/39/7wecmrcos DZLifbC = (7) with 6 DIN ISO 281 Suppl 5:201
25、1-10 ()()92291081434/127/2992c1104,111121444,134+=f (8) 3.2.2 Basic dynamic axial load rating 3.2.2.1 Thrust roller bearings with contact angle 90 The basic dynamic axial load rating of a hybrid thrust roller bearing with contact angle 90 is given by the following equation: ()27/29we4/39/7wecmatanco
26、s DZLfbC = (9) with ()()92291081434/127/2992c11111148570,355+=f (10) 3.2.2.2 Thrust roller bearings with contact angle = 90 The basic dynamic axial load rating of a hybrid thrust roller bearing with contact angle = 90 is given by the following equation: 27/29we4/39/7wecmaDZLfbC = (11) with 92c955808
27、,304 =f (12) where Z is the number of rolling elements carrying load in one direction. 3.2.3 Rating factors for hybrid roller bearings The values for the rating factors bm, and used in Equations (7) to (12) for the different kinds of hybrid roller bearings are given in Table 2. Table 2 Rating factor
28、s for hybrid roller bearings Bearing type mb Radial roller bearing 1,7 0,83 Thrust roller bearing 1,55 0,73 sin15,01 7 DIN ISO 281 Suppl 5:2011-10 4 Fatigue load limit Cu4.1 General The fatigue load limit Cuis generally calculated in accordance with DIN ISO 281:2010-10, Annex B, however when calcula
29、ting the fatigue load limit of a single contact (see DIN ISO 281:2010-10, B.3.2) the different elastic properties of the ceramic rolling element shall be taken into account. For the calculation of the fatigue load limit, the actual curvature radii of ball and raceways shall be used. 4.2 Fatigue load
30、 limit of a single contact 4.2.1 Ball bearings By way of derogation from DIN ISO 281:2010-10 the fatigue load limit at a single inner ring shaft washer raceway contact is calculated as ()2iiS2C E,S2SE,i3Huui1121332+=EEEQ (13) At the outer ring housing washer raceway contact the following equation ap
31、plies: ()2eeC2C E,S2SE,e3Huue1121332+=EEEQ (14) For the typical material properties of rolling bearing steel E, S= 0,3 and ES= 207 000 N/mm2and silicon nitride E, C= 0,26 and EC= 315 000 N/mm2the above equations can be simplified to ()2ei,ei,e,i3Hu10eui,103533,4=EQ (15) The calculation of the Hertzi
32、an parameters and )(E is described in DIN ISO 281:2010-10, B.3.2.1.2. For a ball bearing with balls made from silicon nitride the fatigue load limit is reduced to about 70 % of the fatigue load limit of a bearing with identical raceways and with balls of identical dimensions made from rolling bearin
33、g steel. 4.2.2 Roller bearings The calculation of the fatigue load limit of a profiled line contact requires a complex numerical calculation in accordance with DIN ISO 281:2010-10, B.3.2.1.3. The modulus of elasticity and the Poissons ratio of the ceramic rolling element shall be taken into account.
34、 For a roller bearing with rollers made from silicon nitride the fatigue load limit is reduced to about 83,6 % of the fatigue load limit of a bearing with rollers of identical dimensions made from rolling bearing steel. 8 DIN ISO 281 Suppl 5:2011-10 9 Bibliography DIN ISO 76, Rolling bearings Static
35、 load ratings DIN ISO 76 Supplement 2, Rolling bearings Static load ratings Supplement 2: Load ratings for hybrid bearings DIN ISO 281, Rolling bearings Dynamic load ratings and rating life 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
