ABMA 9-2015 Load Ratings And Fatigue Life For Ball Bearings.pdf

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1、1 Load Ratings And Fatigue Life For Ball Bearings ANSI/ABMA 9:2015 (Revision of ANSI/ABMA 9:1990) ANSI/ABMA 9:2015 Secretariat American Bearing Manufacturers Association ANSI/ABMA 9:2015 Accredited Standards Committee B3 AMERICAN NATIONAL STANDARD (This is not an approved part of the standard) Appro

2、val of an American National Standard requires verification by ANSI that the requirements for due process, consensus, and other criteria for approval have been met by the standards developer. Consensus means substantial agreement has been reached by directly and materially affected interests. This si

3、gnifies the concurrence of more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered, and that an effort be made toward their resolution. The use of an American National Standard is completely voluntary; their existence does not in any

4、 respect preclude anyone, whether they approved the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standard. The American National Standards Institute does not develop standards and will in no circumstances give an interp

5、retation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interpretations should be addressed to the secretariat of the sponsor w

6、hose name appears on the title page of this standard. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute or

7、 online at www.ANSI.org. Published by American Bearing Manufacturers Association 2025 M Street, N.W., Suite 800 Washington, DC 20036 Copyright 2015 by American Bearing Manufacturers Association All rights reserved. No part of this publication may be reproduced in any form, in an electronic retrieval

8、 system or otherwise, without prior written permission of the publisher. Printed in the United States of America i Load Ratings and Fatigue Life For Ball Bearings CONTENTS SECTION PAGE 1. Introduction 1 1.1 Purpose of Standard . 1 1.2 Life Criterion . 1 1.3 Static Load Criterion . 1 2. Symbols . 2 3

9、. Definitions . 3 3.1 Life . 3 3.2 Reliability 3 3.3 Static Load . 4 3.4 Pitch Diameter of a Ball Set, Dpw 4 3.5 Rating Life . 4 3.6 Basic Rating Life, L10 . 4 3.7 Adjusted Rating life, Lna . 4 3.8 Basic Dynamic Radial Load Rating, Cr . 4 3.9 Basic Static Radial Load Rating, C0r . 4 3.10 Basic Dynam

10、ic Axial Load Rating, Ca . 4 3.11 Basic Static Axial Load Rating, C0a 4 3.12 Dynamic Equivalent Radial Load, Pr 4 3.13 Static Equivalent Radial Load, P0r 5 3.14 Dynamic Equivalent Axial Load, Pa 5 3.15 Static Equivalent Axial Load, P0a 5 3.16 Static Safety Factor, S0 5 3.17 Nominal Contact Angle, .

11、5 3.18 Conventional Operating Conditions . 5 3.19 Viscosity ratio, 5 3.20 Film Parameter, 5 3.21 Pressure-viscosity Coefficient 5 3.22 Bearing Arrangements: Paired Mounting 5 3.23 Bearing Arrangements: Back-to-back 5 3.24 Bearing Arrangements: Face-to-face 5 3.25 Bearing Arrangements: Tandem 6 4. Sc

12、ope . 6 4.1 Bearing Types . 6 4.1.1 General 6 4.1.2 Radial, Deep Groove and Angular Contact . 6 4.1.3 Filling Slot, Deep Groove . 6 4.1.4 Radial, Self-Aligning . 6 4.1.5 Thrust . 6 4.1.6 Double Row, Radial and Angular Contact . 6 4.2 Limitations 6 4.2.1 Truncated Contact Area 6 4.2.2 Materials 6 4.2

13、.3 Bearing Types . 7 4.2.4 Lubrication . 7 4.2.5 Ring Support and Alignment 7 4.2.6 Internal Clearance . 7 4.2.7 High Speed Effects 7 4.2.8 Interference Fits . 7 4.2.9 Residual Stress 7 4.2.10 Groove Radii . 7 4.2.11 Tolerances 8 4.2.12 Plastic Deformation in the Contact Area 8 ii 4.3 Operating Para

14、meters . 8 5 Radial and Angular Contact Ball Bearings 9 5.1 Basic Dynamic Radial Load Rating . 9 5.1.1 Basic Dynamic Radial Load Rating for Single Bearings 9 5.1.2 Basic Dynamic Radial Load Rating for Bearing Combinations 9 5.2 Dynamic Equivalent Radial Load 12 5.2.1 Dynamic Equivalent Radial Load f

15、or Single Bearings 12 5.2.2 Dynamic Equivalent Radial Load for Bearing Combinations 12 5.3 Basic Rating Life . 12 5.3.1 Life Equation 12 5.3.2 Loading Restriction on the Life Equation . 15 5.4 Basic Static Radial Load Rating . 15 5.4.1 Basic Static Radial Load Rating for Single Bearings . 15 5.4.2 B

16、asic Static Radial Load Rating for Bearing Combinations . 15 5.5 Static Equivalent Radial Load . 17 5.5.1 Static Equivalent Radial Load for Single Bearings . 17 5.5.2 Static Equivalent Radial Load for Bearing Combinations . 17 6 Thrust Ball Bearings 18 6.1 Basic Dynamic Axial Load Rating 18 6.1.1 Ba

17、sic Dynamic Axial Load Rating for Single-row Bearings . 18 6.1.2 Basic Dynamic Axial Load Rating for Bearings with Two or More Rows of Balls 18 6.2 Dynamic Equivalent Axial Load . 20 6.3 Basic Rating Life 21 6.3.1 Life Equation 21 6.3.2 Loading Restriction on the Life Equation . 21 6.4 Basic Static

18、Axial Load Rating 21 6.5 Static Equivalent Axial Load 21 7 Static Safety Factor . 22 7.1 General 22 8 Adjusted rating Life . 22 8.1 General 22 8.2 Limitations . 23 8.3 Life Adjustment Factor for Reliability, a1 23 8.4 Life Adjustment Factor for Special Bearing Properties, a2 23 8.5 Life Adjustment F

19、actor for Operating Conditions, a3 . 24 8.5.1 General 24 8.5.2 Viscosity Ratio 24 8.5.3 Calculation of Life Under Low Load Conditions 25 iii LIST OF TABLES TABLE NO. TITLE PAGE RADIAL AND ANGULAR CONTACT BALL BEARINGS 1 Values for fcm for Radial and Angular Contact Ball Bearings . 10 2 Values for X

20、and Y for Radial and Angular Contact Ball Bearings 13 3 Values for f0 for Ball Bearings . 16 4 Values for X0 and Y0 for Radial Ball Bearings . 17 THRUST ROLLER BEARINGS 5 Values for fcm for Thrust Ball Bearings 19 6 Values for X and Y for Thrust Ball Bearings 20 7 Guideline Values for the Static Saf

21、ety Factor S0 for Ball Bearings . 22 8 Life Adjustment Factor for Reliability, a1 23 LIST OF FIGURES FIGURE NO. TITLE PAGE 1 Reference Kinematic Viscosity, 1 25 1 Load Ratings and Fatigue Life for Ball Bearings 1. INTRODUCTION 1.1 Purpose of Standard Ball bearing performance is a function of many va

22、riables. These include the bearing design, the characteristics of the material from which the bearings are made, the way in which they are manufactured, as well as many variables associated with their application. The only sure way to establish the satisfactory operation of a bearing selected for a

23、specific application is by actual performance in the application. As this is often impractical, another basis is required to estimate the suitability of a particular bearing for a given application. This is the purpose of this standard. This standard specifies the method of calculating the basic dyn

24、amic load rating of rolling bearings within the size ranges shown in the relevant ANSI/ABMA standards, manufactured from contemporary, commonly used, good quality hardened bearing steel in accordance with good manufacturing practice and basically of conventional design as regards the shape of rollin

25、g contact surfaces. This standard also specifies the method of calculating the basic rating life, which is the life associated with 90% reliability, with commonly used high quality material, good manufacturing quality and with conventional operating conditions. In addition, it specifies the method o

26、f calculating adjusted rating life, in which various reliabilities, special bearing properties and specific operating conditions are taken into account by means of life adjustment factors. Furthermore, this standard specifies the method of calculating the basic static load rating and the static equi

27、valent load for ball bearings within the size ranges shown in the relevant ANSI/ABMA Standards, manufactured from good quality hardened bearing steel, in accordance with good manufacturing practice and basically of conventional design as regards the shape of rolling contact surfaces. 1.2 Life Criter

28、ion Even if ball bearings are properly mounted, adequately lubricated, protected from foreign matter, and are not subjected to extreme operating conditions, they can ultimately fatigue. Under ideal conditions, the repeated stresses developed in the contact areas between the ball and the raceways eve

29、ntually can result in fatigue of the material which manifests itself as spalling of the load carrying surfaces. In most applications the fatigue life is the maximum useful life of a bearing. This fatigue is the criterion of life used as the basis for the first part of this standard. Fatigue life cal

30、culated in accordance with this standard does not represent the maximum that can be attained by applying all known technology to ball bearing design and application. Neither does it represent the minimum that should be expected of a bearing made by a producer lacking skill and experience in the desi

31、gn and manufacture of ball bearings, even though the bearing meets the geometric parameters given below. The calculated fatigue life represents the performance normally expected from high quality bearings made by reputable manufacturers. Manufacturers can supply longer lived bearings by the applicat

32、ion of advanced materials and manufacturing processes. The present standard has evolved as a means for bearing users to specify a reasonable standard of performance for the bearing they wish to purchase. 1.3 Static Load Criterion A static load is a load acting on a non-rotating bearing. Permanent de

33、formations appear in balls and raceways under a static load of moderate magnitude and increase gradually with increasing load. It is often impractical to establish whether the deformations appearing in a bearing in a specific application are permissible by testing the bearing in that application. Ot

34、her methods are therefore required to establish the suitability of the bearing selected. 2 Experience shows that a total permanent deformation of 0.0001 of the rolling element diameter, at the center of the most heavily loaded ball/raceway contact, can be tolerated in most bearing applications witho

35、ut the subsequent bearing operation being impaired. The basic static load rating is, therefore, given a magnitude such that approximately this deformation occurs when the static equivalent load is equal to the load rating. Tests indicate that a load of the magnitude in question may be considered to

36、correspond to a calculated contact stress of; 4,600 MPa (667,000 psi) for self-aligning ball bearings, and 4,200 MPa (609,000 psi) for all other ball bearings at the center of the most heavily loaded rolling element/raceway contact. The formulae and factors for the calculation of the basic static lo

37、ad ratings are based on these contact stresses. The permissible static equivalent load may be smaller than, equal to or greater than the basic static load rating, depending on the requirements for smoothness of operation and friction, as well as on actual contact surface geometry. Bearing users with

38、out previous experience of these conditions should consult the bearing manufacturers. 2. SYMBOLS a1 life adjustment factor for reliability a2 life adjustment factor for special bearing properties a3 life adjustment factor for operating conditions Ca basic dynamic axial load rating, in newtons (pound

39、s) Cr basic dynamic radial load rating, in newtons (pounds) C0a basic static axial load rating, in newtons (pounds) C0r basic static radial load rating, in newtons (pounds) Dpw pitch diameter of ball set, in millimeters (inches) Dw nominal ball diameter, in millimeters (inches) e limiting value of F

40、a/Fr for the applicability of different values of factors X and Y Fa bearing axial load (axial component of the actual bearing load), in newtons (pounds) Fr bearing radial load (radial component of the actual bearing load), in newtons (pounds) fcm factor which depends on the geometry of the bearing components, the accuracy to which the various components are made, and the material f0 factor for calculation of basic static load rating. i number of rows of rolling elements Lna adjusted ratin