1、May 2010 Translation by DIN-Sprachendienst.English price group 8No 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 21.
2、100.20!$|Y“1895456www.din.deDDIN 732Rolling bearings Thermally safe operating speed Calculation and correction valuesEnglish translation of DIN 732:2010-05Wlzlager Thermisch zulssige Betriebsdrehzahl Berechnung und Beiwerte,Englische bersetzung von DIN 732:2010-05Roulements Admissible vitesse de rfr
3、ence thermique Calculs et facteurs de correction,Traduction anglaise de DIN 732:2010-05www.beuth.deDocument comprises 12 pagesIn case of doubt, the German-language original shall be considered authoritative.08.12,DIN 732:2010-05 2 A comma is used as the decimal marker. Contents Page Foreword 3 1 Sco
4、pe 4 2 Normative references 4 3 Terms and definitions .4 4 Symbols and units .5 5 Calculation 6 5.1 Calculating the thermally safe operating speed n6 5.2 Lubricant factor KL.8 5.3 Load factor KP8 5.4 Determining the total heat emitted .8 Annex A (informative) Coefficients f0and f110 Bibliography . 1
5、2 Figures Figure 1 Speed ratio fn.7 Figure 2 Thermal transmittance kqas a function of bearing seating area AS.9 Tables Table 1 Symbols and units 5 Table A.1 Guidance values of coefficients f0and f110 DIN 732:2010-05 3 Foreword This standard has been prepared by Working Committee NA 118-01-08 AA Trag
6、zahlen und Lebensdauer of the Normenausschuss Wlz- und Gleitlager (Rolling Bearings and Plain Bearings Standards Committee). DIN 732:2010-05 4 1 Scope This standard describes a method of calculating the thermally safe operating speed (i.e. the maximum permissible operating speed) of rolling bearings
7、 under given operating conditions. The method is only to be used if the thermally safe operating speed is a function of the heat emitted by the bearing. Otherwise, the method is unsuitable. The method shall not be used for thrust ball bearings, as for these bearings the thermally safe operating spee
8、d does not depend on the bearing temperature. The method is applicable to bearings without contacting seals. Where bearings are sealed, due consideration is to be given to the seal characteristics. 2 Normative references The following referenced documents are indispensable for the application of thi
9、s document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. DIN ISO 76, Rolling bearings Static load ratings DIN ISO 281, Rolling bearings Dynamic load ratings and rating life DIN ISO 1132
10、-1, Rolling bearings Tolerances Part 1: Terms and definitions DIN ISO 5593, Rolling bearings Vocabulary DIN ISO 15312, Rolling bearings Thermal speed rating Calculation and coefficients ISO 3031, Rolling bearings Thrust needle roller and cage assemblies, thrust washers Boundary dimensions and tolera
11、nces ISO 15241, Rolling bearings Symbols for quantities 3 Terms and definitions For the purposes of this document, the terms, definitions and symbols in DIN ISO 1132-1, DIN ISO 5593 and the following apply. 3.1 thermally safe operating speed nspeed at which the mean bearing temperature reaches a spe
12、cified value under given operating conditions NOTE Mechanical and kinematic criteria that could lead to further speed limitations are not taken into account when determining the thermally safe operating speed. 3.2 heat emitting bearing seating area ASsum of contact areas between inner ring (shaft wa
13、sher) and shaft and between outer ring (housing washer) and housing through which the heat is emitted NOTE As a simplification, the heat emitting reference surface area as in DIN ISO 15312 may be used as the bearing seating area. DIN 732:2010-05 5 3.3 operating load P1bearing load, in the form of a
14、radial, axial or combined load, which, under operating conditions, produces the load-dependent frictional moment 3.4 density of heat flow rate q ratio of the heat flow through the bearing seating to the seating area 3.5 ambient temperature Amean environmental temperature for the bearing assembly und
15、er the operating conditions 3.6 operating temperature mean temperature of the stationary ring (normally, the outer ring) or the housing washer of the bearing under the operating conditions 4 Symbols and units For the purposes of this standard, the symbols given in ISO 15241 and the following apply.
16、Table 1 Symbols and units Symbol Quantity Unit ASHeat emitting bearing seating area mm2C0Load rating (C0rfor radial bearings and C0afor axial bearings) as in DIN ISO 76 N cLSpecific heat capacity of lubricant kJ/(kg K) D Bearing outside diameter mm d Bearing bore diameter mm dMMean diameter of beari
17、ng; dM= 0,5 (D + d) mm e Limiting value for Fa/Frratio, as in DIN ISO 281 FaAxial load (axial component of actual load) N FrRadial load (radial component of actual load) N fnSpeed ratio n/nr f0Coefficient for the load-independent frictional moment under the reference conditions f1Coefficient for the
18、 load-dependent frictional moment under the reference conditions KLLubricant factor KPLoad factor kqThermal transmittance W/(mm2 K) nThermally safe operating speed min1nrThermal speed rating min1P1Operating load N DIN 732:2010-05 6 Table 1 (continued) Symbol Quantity Unit P0Static equivalent load as
19、 in DIN ISO 76 N q Density of heat flow rate W/mm2VLLubricant volume flow rate l/min Y Dynamic axial load factor as in DIN ISO 281 Contact angle Operating temperature C AAmbient temperature C iTemperature of lubricant fed C oTemperature of lubricant discharged C V Kinematic viscosity of lubricant un
20、der operating conditions (with the bearing at operating temperature ) mm2/s LDensity of lubricant fed kg/dm3 Heat emitted W EAdditional heat generated by external cooling or heating W LHeat emitted by lubricant W SHeat emitted via bearing seating W 5 Calculation 5.1 Calculating the thermally safe op
21、erating speed nCalculation of the thermally safe operating speed is based on the thermal balance for the bearing under operating conditions. By analogy with the thermal speed rating as in DIN ISO 15312, the speed is determined at which the bearing reaches its operating temperature in the application
22、 considered. Taking into account the frictional work, the heat emitted shall be calculated as follows: ( ) =+M113M3/2073101030dPfdnvfn(1) This equation can only be resolved by iteration. Introducing a lubricant factor KL, the load factor KP, and the speed ratio fn, the equation can be simplified as
23、follows: 1nP3/5nL=+ fKfK(2) with fndetermined by iteration or, for 0,01 KL 10 and 0,01 KP 10, determined approximately by Equation (3), as follows: 832,0P055,0L963,0P599,0Ln5,50488,85278,498177,490KKKKf+=(3) Then, the thermally safe operating speed nis obtained using the following equation: rnnfn =(
24、4) DIN 732:2010-05 7 In Figure 1, the speed ratio is plotted as a function of factors KLand KP. Key fnspeed ratio n/nr KLlubricant factor KPload factor Figure 1 Speed ratio fnDIN 732:2010-05 8 5.2 Lubricant factor KLThe lubricant factor KLshall be calculated as follows: 3M3/2r3/207r3L103010dnfnK=(5)
25、 NOTE The term3M3/2r3/20710 dnf is expressed in N mm.5.3 Load factor KPThe lubricant factor KPshall be calculated as follows: M11r3P3010dPfnK= (6) Coefficients f0and f1and the equivalent load P1relevant for the load-dependent friction moment under operating conditions can be taken from Annex A. 5.4
26、Determining the total heat emitted The total heat emitted is to be calculated as the sum of heat flows, as follows: ELS +=(7) The heat flow from the bearing seat AS shall be calculated as follows: ( )SqASAk = (8) Since the thermal transmittance kqdepends on the way the bearing is mounted and is also
27、 a function of the housing design, size and material, it may differ widely. In standard applications, kqranges between 0,000 2 W/(mm2 K) and 0,001 W/(mm2 K) for seating areas up to about 50 000 mm2. For the reference heat flow density given DIN ISO 15312, the thermal transmittance is as shown in Fig
28、ure 2. DIN 732:2010-05 9 Key kqthermal transmittance, in W/(mm2 K) ASheat emitting bearing seating area, in mm2Figure 2 Thermal transmittance kqas a function of bearing seating area ASWhere the exact size of heat emitting seating areas is unknown, the reference seating area as in DIN ISO 15312 may b
29、e used as an approximation. The heat emitted by the lubricant for oil bath lubrication is to be calculated by: ( ) 0001601LioLLL= Vc (9) For standard mineral oils with a specific heat capacity in kJ/(kg K) of 88,1L=c(10) and a density in kg/dm3 91,0L=(11) the following is obtained: ( )LioL5,28 V= (1
30、2) DIN 732:2010-05 10 Annex A (informative) Coefficients f0and f1Table A.1 lists guidance values of coefficients f0and f1for the calculation of bearings of different types without contacting seals. They are the result of both extensive experimental investigations and the analysis of empirical values
31、 to be found in literature. It should be noted that in practice, depending on bearing design and quality, the coefficients may differ from the values given below. The f0values are those for bearings with oil bath lubrication, it being assumed that the oil level reaches up to mid-height of the lower
32、rolling element. As the oil level rises, the coefficient can reach a value up to three times the values given in the table. For grease lubrication, f0is about half up to two-thirds of the values given in Table A.1, it being assumed that the bearings have run in for a while. Where bearings have recei
33、ved new grease, f0can reach twice to five times the values given below. The values of f1are the same for oil bath and grease lubrication. The dimension series used in Table A.1 are those from ISO 15 and ISO 104. Table A.1 Guidance values of coefficients f0and f1Bearing type Dimension series f0f1P1Si
34、ngle-row deep groove ball bearings 18 1,7 0,000 5 (P0/C0)0,53,3 Fa 0,1 Fra28 1,7 0,000 5 (P0/C0)0,538 1,7 0,000 5 (P0/C0)0,519 1,7 0,000 7 (P0/C0)0,539 1,7 0,000 7 (P0/C0)0,500 1,7 0,000 7 (P0/C0)0,510 1,7 0,000 7 (P0/C0)0,502 2 0,000 9 (P0/C0)0,503 2,3 0,000 9 (P0/C0)0,504 2,3 0,000 9 (P0/C0)0,5Sel
35、f-aligning ball bearings 02 2,5 0,000 3 (P0/C0)0,4max 1,37 Fa/e 0,1 Fr;Fr 22 3 0,000 3 (P0/C0)0,403 3,5 0,000 3 (P0/C0)0,423 4 0,000 3 (P0/C0)0,4Single-row angular contact ball bearings, with 22 e Fr(1 + 0,6 Fa/(e Fr)3) if Fa/Fr e 30 4,5 0,000 75 (P0/C0)0,540 6,5 0,001 2 (P0/C0)0,531 5,5 0,001 2 (P0
36、/C0)0,541 7 0,002 2 (P0/C0)0,522 4 0,000 5 (P0/C0)0,3332 6 0,001 6 (P0/C0)0,503 3,5 0,000 5 (P0/C0)0,3323 4,5 0,000 8 (P0/C0)0,33Tapered roller bearings 02 03 30 29 20 22 23 13 31 32 3 3 3 3 3 4,5 4,5 4,5 4,5 4,5 0,000 40 0,000 40 0,000 40 0,000 40 0,000 40 0,000 40 0,000 40 0,000 40 0,000 40 0,000
37、40 max 2 Y Fa;Fr,for paired bearings: max 1,21 Y Fa;Fr Double-row cylindrical roller bearings, full complement 48 49 50 9 11 13 0,000 55 0,000 55 0,000 55 FrThrust cylindrical roller bearing 11 12 3 4 0,001 50 0,001 50 FaThrust needle roller bearings b 5 0,001 50 FaThrust spherical roller bearings 9
38、2 93 94 3,7 4,5 5 0,000 30 0,000 40 0,000 50 Fa,for Fr 0,55 FaThrust spherical roller bearings, modified design (optimized internal design) 92 93 94 2,5 3 3,3 0,000 23 0,000 30 0,000 33 Fa,for Fr 0,55 FaaIf P1 Fr,then P1= Fr.bDimension series as in ISO 3031. DIN 732:2010-05 12 Bibliography Palmgren, A.: Ball and Roller Bearing Engineering, 3rd ed., Burbank, Philadelphia (1959) ISO 15, Rolling bearings Radial bearings Boundary dimensions, general plan ISO 104, Rolling bearings Thrust bearings Boundary dimensions, general plan ISO 5753, Rolling bearings Radial internal clearance
