1、BRITISH STANDARD BS ISO/TR 14179-2:2001 Gears Thermal capacity Part 2: Thermal load carrying capacity ICS 21.200 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS ISO/TR 14179-2:2001 This British Standard, having been prepared under the direction of the Engineering Sector Poli
2、cy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee and comes into effect on 24 September 2001 BSI 24 September 2001 ISBN 0 580 38497 7 National foreword This British Standard reproduces verbatim ISO/TR 14179-2:2001 and implements it as the UK
3、national standard. The UK participation in its preparation was entrusted to Technical Committee MCE/5, Gears, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement int
4、ernational or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to in
5、clude all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/Eur
6、opean committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO/TR title, pa
7、ges ii to v, a blank page, pages 1 to 34, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsReference number ISO/TR 14179-2:2001(E) OSI 1002 TECHNICAL REPORT
8、ISO/TR 14179-2 First edition 2001-08-01 Gears Thermal capacity Part 2: Thermal load-carrying capacity Engrenages Capacit thermique Partie 2: Capacit de charge thermiqueii ISO 1002 All irhgts seredevrISO/TR 14179-2:2001(E) ISO 1002 All rights rsedevre iii Contents Page Foreword.iv Introduction.v 1 Sc
9、ope 1 2 Symbols, units and indices 1 3 Principle6 3.1 General6 3.2 Purpose and applicability .6 4 Equivalent transmitted power 7 5 Power loss8 5.1 General8 5.2 Gear losses.8 5.3 Bearing losses .15 5.4 Shaft seals19 6 Heat dissipation .19 6.1 General19 6.2 Heat dissipation through the housing.19 6.3
10、Heat dissipation via the foundation.22 6.4 Heat dissipation via shafts and couplings24 6.5 Heat dissipation via an external cooler .26 7 Results of calculation27 7.1 Splash lubrication27 7.2 Injection lubrication.27 8 Sample calculation 27 8.1 General27 8.2 Geometry and surrounding conditions .27 8.
11、3 Power loss30 8.4 Heat dissipation .32 8.5 Comparison33 Bibliography34ISO/TR 14179-2:2001(E) iv ISO 1002 All rights rsedevre Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Internatio
12、nal Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO
13、, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. The main task of technical com
14、mittees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. In exceptional circumstanc
15、es, when a technical committee has collected data of a different kind from that which is normally published as an International Standard (“state of the art”, for example), it may decide by a simple majority vote of its participating members to publish a Technical Report. A Technical Report is entire
16、ly informative in nature and does not have to be reviewed until the data it provides are considered to be no longer valid or useful. Attention is drawn to the possibility that some of the elements of this part of ISO/TR 14179 may be the subject of patent rights. ISO shall not be held responsible for
17、 identifying any or all such patent rights. ISO/TR 14179-2 was prepared by Technical Committee ISO/TC 60, Gears, Subcommittee SC 2, Gear capacity calculation. ISO/TR 14179 consists of the following parts, under the general title Gears Thermal capacity : Part 1: Rating gear drives with thermal equili
18、brium at 95 C sump temperature Part 2: Thermal load-carrying capacityISO/TR 14179-2:2001(E) ISO 1002 All rights rsedevre v Introduction ISO/TR 14179-1 is the American proposal. It utilizes an analytical heat balance model to calculate the thermal transmittable power for a single or multiple stage ge
19、ar drive lubricated with mineral oil. Many of the factors in the analytical model can trace their roots to published works of various authors. The procedure is based on the calculation method presented in AGMA (American Gear Manufacturers Association) Technical Paper 96FTM9. The bearing losses are c
20、alculated from catalogue information supplied by bearing manufacturers, which in turn can be traced to the work of Palmgren. The gear windage and churning loss formulations originally appeared in work presented by Dudley, and have been modified to account for the effects of changes in lubricant visc
21、osity and amount of gear submergence. The gear load losses are derived from the early investigators of rolling and sliding friction who approximated gear tooth action by means of disk testers. The coefficients in the load loss equation were then developed from a multiple parameter regression analysi
22、s of experimental data from a large population of tests in typical industrial gear drives. These gear drives were subjected to testing which varied operating conditions over a wide range. Operating condition parameters in the test matrix included speed, power, direction of rotation and amount of lub
23、ricant. The formulation has been verified by cross checking predicted results to experimental data for various gear drive configurations from several manufacturers. This part of ISO/TR 14179 is based on a German proposal whereby the thermal equilibrium between power loss and dissipated heat is calcu
24、lated. From this equilibrium, the expected gear oil sump temperature for a given transmitted power, as well as the maximum transmittable power for a given maximum oil sump temperature, can be calculated. For spray lubrication, it is also possible to calculate the amount of external cooling necessary
25、 for maintaining a given oil inlet temperature. The calculation is an iterative method. The power loss of cylindrical, bevel and hypoid and worm gears can be calculated according to theoretical and experimental investigations into those different gear types undertaken at the Technical University in
26、Munich. The load dependent gear power loss results in the calculation of the coefficient of mesh friction. The influence of the main parameters of load, speed, viscosity and surface roughness on the coefficient of friction were measured individually in twin disk tests and verified in gear experiment
27、s. The same equations for the coefficient of friction are used in ISO/TR 13989 for the calculation of the scuffing load capacity of gears, and are used in German standard methods for the calculation of the relevant temperature for oil film thickness to evaluate the risk of wear and micropitting. The
28、 no-load power loss of gears is derived from systematic experiments with various parameters from published research projects. The power loss calculation of the anti-friction bearings was taken from the experience of the bearing manufacturers, as published in their most recent catalogues. The equatio
29、ns for heat dissipation are based on theoretical considerations combined with experimental investigations on model gear cases using different gear wall configurations in natural and forced convection. Radiation from the housing is based on the Stefan-Boltzman law, with measured values of the relativ
30、e radiation coefficient measured for different surface finish and coatings of the gear case surface. Also included are equations for the calculation of the heat transfer from rotating parts and to the foundation. The results were verified with heat dissipation measurements in practical gear drives.
31、A computer program, “WTplus”, with the proposed thermal calculation method, was developed within a research project of the FVA (Forschungsvereinigung Antriebstechnik e.V., Frankfurt) and is widely used in the German gear industry.TECHNICAL REPORT ISO/TR 14179-2:2001(E) ISO 1002 All rights rsedevre 1
32、 Gears Thermal capacity Part 2: Thermal load-carrying capacity 1 Scope This part of ISO/TR 14179 presents a means for determining the thermal load carrying capacity of gears that includes measurement on original gear units under practical conditions. This takes the form of either measurement of the
33、power loss, heat dissipation or both, or, in the case of splash-lubricated gear units, the determination of the quasi-stationary temperature in the oil sump. The methods of calculation for all individual components of power loss and heat dissipation described in this part of ISO/TR 14179 are to be r
34、egarded as an alternative method. 2 Symbols, units and indices For the purposes of this part of ISO TR 14179, the symbols, units and indices given in Table 1 apply. Table 1 Symbols, units and indices Symbol Meaning Units a Centre distance mm A bot Gear unit bottom area m 2 A ca Overall housing area
35、(external) m 2 A foot Footprint of gear unit m 2 A oil Overall housing area (internal) m 2 A pro Projected fin area (housing external) m 2 A q Cross-sectional area m 2 A fin Total fin area (housing external) m 2 A air Ventilated housing area m 2 b Tooth width, bearing width mm b eH Tooth contact wid
36、th mm b 0 Reference value of tooth width, b 0 10 mm mm C lub Lubrication factor C Sp Splash oil factor ISO/TR 14179-2:2001(E) 2 ISO 1002 All rights rsedevre Table 1 (continued) Symbol Meaning Units C 0 Static load rating of anti-friction bearing N C 1,2 Factors d a Ti pci rcl ed ia me te r mm d fl E
37、quivalent flange diameter m d w P i tchci rcl edi a me te r mm d m Mean bearing diameter mm d s Pitch circle diameter of equivalent crossed helical gears mm d sh Shaft diameter m e Base of natural logarithm, e 2,718 f 0, 1, 2 Coefficients for bearing losses ED Duty factor F a Bearing thrust load N F
38、 t Force at pitch circle N F bt Tooth normal force, transverse section N F n Tooth normal force, normal section N F r Radial bearing load N g g 9,81 m/s 2 m/s 2 Gr Grashoff number h c Height of point of contact above the lowest point of the immersing gear mm h ca Overall height of gear unit housing
39、m H v Tooth loss factor h e1,e2 Tip circle immersion depth with oil level stationary mm h e0 Reference value of immersion depth, h e0 10 mm mm h e, max Max. Tip circle immersion depth with oil level stationary mm H oil Enthalpic flow with oil W h 0, 1 Lubrication gap heights mm k Heat transmission c
40、oefficient W/(m 2 K) l fl Equivalent length of coupling flange m l h Hydraulic length 4 A G /U M mm l fin Depth of one fin m l x Flow length (path of flow filament along housing wall) m l sh Length of free shaft end mISO/TR 14179-2:2001(E) ISO 1002 All rights rsedevre 3 Table 1 (continued) Symbol Me
41、aning Units m, m * Fin factors m Module mm n Rotational speed 1/min Nu Nusselt number P A Input power W P Aeq Equivalent input power W Pr Prandtl number P V Power loss W P VD Seal power loss W P VL Bearing power loss W P Vx Auxiliary power losses W P VZ Gear power loss W P 0 Equivalent static bearin
42、g load N P 1 Equivalent bearing load N Q Total heat flow W Q ca Heat flow across housing surface W Q fun Heat flow across foundation W Q rot Heat flow across shafts and couplings W Re Reynolds number Ra 1, 2 Arithmetic average roughness of pinion and gear wheel m Rz Average roughness depth m Rz 0 Re
43、ference roughness depth for worm gear units (Rz 0 3m) m s Size factor of bearing t Duration min T H Hydraulic loss torque N m T VL Total bearing loss torque N m T VL0 No-load bearing loss torque N m T VLP1,2 Load dependent bearing loss torque N m T wall Temperature of housing wall K T air Cooling ai
44、r temperature K T perm Maximum permissible gear unit temperature K T Ambient temperature K u Gear ratio ISO/TR 14179-2:2001(E) 4 ISO 1002 All rights rsedevre Table 1 (continued) Symbol Meaning Units U Circumference of the foundation m v Mean peripheral speed m/s v t Tangential speed m/s v t0 Referen
45、ce tangential speed m/s . oil V Oil injection rate l/min . 0 V Reference oil injection rate, . 0 V 2l /mi n l/min v gm Mean sliding speed m/s v gs Helical speed m/s v gy1,2 Total surface speed at tooth tip m/s v S Oil jet velocity m/s v t Peripheral speed at pitch circle m/s v t0 Reference speed, v
46、t0 10 m/s m/s v air Impingement velocity m/s v C Sum velocity at pitch point m/s v h Sum velocity in direction of tooth depth m/s v m Mean resultant sum velocity m/s v s Sum velocity in direction of tooth length m/s x Addendum modification factor X L Oil Lubricant factor X R Roughness factor Y Axial
47、 factor from bearing tables, Y for F a /F r e Y W Material factor z Number of teeth fun Heat transfer coefficient at gear unit foundation W/(m 2 K) ca Air-side heat transfer coefficient at housing W/(m 2 K) con Heat transfer coefficient due to convection W/(m 2 K) K,free Heat transfer coefficient du
48、e to free convection W/(m 2 K) K,forced Heat transfer coefficient due to forced convection W/(m 2 K) oil Oil-side heat transfer coefficient W/(m 2 K) rad Heat transfer coefficient due to radiation W/(m 2 K) rot Heat transfer coefficient at rotating shafts W/(m 2 K)ISO/TR 14179-2:2001(E) ISO 1002 All
49、 rights rsedevre 5 Table 1 (continued) Symbol Meaning Units * sh,face Heat transfer coefficient at the face of a shaft W/(m 2 K) t Transverse pressure angle wt Working pressure angle Helix angle b Helix angle at base circle fin Thickness of one fin m wall Mean housing wall thickness m Emission ratio of gear unit housing Profile contact ratio 1,2 Addendum contact ratio, pinion/gear wheel fun The
