Nippon Thompson o., t. is a bearing manufacturer that launche the technical evelopment of neele roller bearings for the first time in apan an is prou of the high quality level an abunant varieties of its proucts. Neele roller bearings are bearings for rotary motion that incorporate neeleshape thin rollers instea of orinary bearing balls or rollers. ompare with other rolling bearings, they are small-size an lightweight but have a large loa capacity. They are wiely use with high reliability in the fiels of automobiles, inustrial machinery, O equipment, etc. as resource-saving type bearings that make the whole machine compact. 1
haracteristics of Neele Roller earings earings can be classifie into two main types, namely rolling bearings an sliing bearings. Rolling bearings can be subivie further into ball bearings an roller bearings accoring to the rolling elements. Neele Roller earings are high-precision rolling bearings with a low sectional height, incorporating neele rollers as the rolling element. They have the following features. lassification of bearings eep groove ball bearings erits of Rolling earings ompare with sliing bearings, rolling bearings have the following merits: Static an kinetic friction is low. Since the ifference between static friction an kinetic friction is small an the frictional coefficient is also small, rive units or machines can be mae more compact an lightweight, saving machine costs an power consumption. Stable accuracy can be maintaine for long perios. Owing to less wear, stable accuracy can be maintaine for long perios. achine reliability is improve. Since the bearing life can be estimate base on rolling fatigue, machine reliability is improve. erits of Neele Roller earings ompare with other rolling bearings, Neele Roller earings have the following avantages: With a low sectional height, they can withstan heavy loas. Since they have a low sectional height compare with other rolling bearings an yet can withstan heavy loas, machines can be mae more compact an lightweight, thus saving costs. Rotating torque is small, improving mechanical efficiency. Since the rotating raius is small, the rotating torque is also small uner the same frictional conitions, thus improving mechanical efficiency. nertia is minimize. Since the bearing volume an weight are small, the moment of inertia of the bearing is minimize when it is put in motion. earings Rolling bearings all bearings Roller bearings Raial ball bearings Thrust ball bearings Raial roller bearings Thrust roller bearings ngular contact ball bearings Self-aligning ball bearings Others Thrust ball bearings with flat back face Thrust ball bearings with aligning seat washer ouble-irection angular contact thrust ball bearings Others Neele roller bearings ylinrical roller bearings Tapere roller bearings Self-aligning roller bearings Others Thrust neele roller bearings Thrust cylinrical roller bearings Thrust tapere roller bearings ubrication is simplifie. Since grease lubrication is sufficient in most cases, lubrication can be simplifie for easy maintenance. ost suite to oscillating motions. any rolling elements are arrange at a small spacing pitch, an this configuration is most suite to oscillating motions. Sliing bearings Others etals, bushings, others
Types Types an eatures an eatures of earings of earings earings can earings be roughly can be classifie roughly into classifie raial into bearings raial an bearings thrust an bearings thrust accoring bearings accoring to applicable to applicable loa irection. loa irection. Raial earings Raial are earings groupe are into groupe Shell into Type Shell Neele Type Roller Neele earings, Roller earings, achine achine Type Neele Type Roller Neele earings, Roller earings, an an various other various types. other Thrust types. earings Thrust are earings groupe are into groupe Thrust into Neele Thrust Roller Neele earings Roller an earings Thrust an Roller Thrust earings. Roller earings. ollower earings ollower that earings are use that for are cam use mechanisms for cam mechanisms an linear an motion linear are motion groupe are into groupe am ollowers into am ollowers an Roller an Roller ollowers. ollowers. rosse Roller earings are special shape bearings that can simultaneously receive loas in all irections with a single bearing. earings other than rolling bearings, such as self-aligning Spherical ushings that can support raial loas an axial loas an POs an -alls that are use for link mechanisms, are also available. lassification lassification of of earings earings Shell Type Shell Type Neele Roller Neele earings Roller earings TT TT TT TT YT YT YT YT Y Y Y Y Raial earings Raial earings Neele Roller Neele ages Roller ages T T Neele Roller Neele ages for Roller eneral ages Usage for eneral Usage TW TW T T Neele Roller Neele ages for Roller ngine ages onnecting for ngine Ros onnecting Ros TV TV NRN NRN TT TT TRTR TRTR achine Type achine Type Neele Roller Neele earings Roller earings RR RR TRTR TRTR RR RR -ube achine -ube Type achine Neele Roller Type Neele earings Roller earings T/S T/S NRN NRN Neele Roller Neele earings Roller with earings Separable with age Separable age NWRNW NWRNW NU NU Roller earings Roller earings Roller earings Roller for Sheaves earings for Sheaves N TRU NS N TRU NS Thrust earings Thrust earings Thrust Neele Thrust Roller Neele earings Roller earings Thrust Roller Thrust earings Roller earings NT NT ZZ ZZ ombine Type earings ombine Type earings ombine Type ombine Type Neele Roller Neele earings Roller earings with Thrust all with earing Thrust all earing with Thrust Roller with earing Thrust Roller earing with ngular ontact with ngular all earing ontact all earing with Three-point with ontact Three-point all earing ontact all earing NXNX NXNX NXNX NXNX NT NT NT NT
Shell Type Neele Roller earings Shell Type Neele Roller earings are lightweight with the lowest sectional height among neele roller bearings with outer ring, because they employ a shell type outer ring mae from a thin special-steel plate which is accurately rawn, carburize an quenche. Since these bearings are press-fitte into the housing, no axial positioning fixtures are require. They are ieal for use in mass-prouce articles that require economy. achine Type Neele Roller earings achine Type Neele Roller earings have an outer ring mae by machining, heat treatment, an grining. The outer ring has stable high rigiity an can be easily use even for light alloy housings. These bearings are available in various types an optimally selectable for ifferent conitions such as heavy loas, high-spee rotation an low-spee rotation. They are most suitable for general-purpose applications. Raial earings Page 1 Raial earing Page 1 Neele Roller ages for eneral Usage Neele Roller ages for ngine onnecting Ros Neele Roller ages for eneral Usage are bearings that isplay excellent rotational performance. Their specially shape cages with high rigiity an accuracy, precisely guie the neele rollers. Since neele rollers with extremely small imensional variations in iameter are incorporate an retaine, Neele Roller ages for eneral Usage are useful in small spaces when combine with shafts an housing bores that are heat treate an accurately groun as raceway surfaces. Raial earing Page 1 Neele Roller ages for ngine onnecting Ros are use for motor cycles, small motor vehicles, outboar marines, snow mobiles, general-purpose engines, highspee compressors, etc. that are operate uner extremely severe an complex operating conitions such as heavy shock loas, high spees, high temperatures, an stringent lubrication. Neele Roller ages for ngine onnecting Ros are lightweight an have high loa ratings an high rigiity as well as superior wear resistance. Raial earing Page 1 Neele Roller earings with Separable age Roller earings n Neele Roller earings with Separable age, the inner ring, outer ring an Neele Roller age are combine, an they can be separate easily. This type has a simple structure with high accuracy. n aition, the raial clearance can be freely selecte by choosing an assembly combination. These bearings have excellent rotational performance, because Neele Roller ages are use. Raial earing Page Roller earings, in which rollers are incorporate in ouble rows, are non-separable heavy-uty bearings. They can withstan not only raial loas but axial loas as well, which are supporte at the contacts between the shoulers of inner an outer rings an the en faces of rollers. Therefore, they are most suitable for use at the fixing sie of a shaft. Raial earing Page 1
Thrust earings Thrust earings consist of a precisely mae cage an rollers, an can receive axial loas. They have high rigiity an high loa capacities an can be use in small spaces. Thrust Neele Roller earings use neele rollers, while Thrust Roller earings use cylinrical rollers. am ollowers am ollowers are bearings with a stu incorporating neele rollers in a thick walle outer ring. They are esigne for outer ring rotation, an the outer rings run irectly on mating cam guie surfaces. Various types of am ollowers are available. They are wiely use as follower bearings for cam mechanisms an for linear motions. Thrust earing Page 1 ollower earing Page 1 ombine Type Neele Roller earings ombine Type Neele Roller earings are combinations of a raial bearing an a thrust bearing. age Neele Roller earings are use as raial bearings an Thrust all earings or Thrust Roller earings are use as thrust bearings. They can be subjecte to raial loas an axial loas simultaneously. Roller ollowers Roller ollowers are bearings in which neele rollers are incorporate in a thick walle outer ring. These bearings are esigne for outer ring rotation, an the outer rings run irectly on mating cam guie surfaces. They are use as follower bearings for cam mechanisms an for linear motions. ombine Type earing Page 1 ollower earing Page nner Rings rosse Roller earings nner Rings are heat-treate an finishe by grining to a high egree of accuracy an are use for Neele Roller earings. n the case of Neele Roller earings, normally the shafts are heat-treate an finishe by grining an use as raceway surfaces. owever, when it is impossible to make shaft surfaces accoring to the specifie surface harness or surface roughness, nner Rings are use. omponent part Page 1 rosse Roller earings are high-rigiity an compact bearings with their cylinrical rollers alternately crosse at right angles to each other between inner an outer rings. single rosse Roller earing can take loas from any irections at the same time such as raial, thrust, an moment loas. These bearings are wiely use in the rotating parts of inustrial robots, machine tools, meical equipment, etc. which require compactness, high rigiity an high rotational accuracy. rosse Roller earing Page 1 1
Spherical ushings Spherical ushings are self-aligning spherical plain bushings, which have inner an outer rings with spherical sliing surfaces. They can take a large raial loa an a bi-irectional axial loa at the same time. They are ivie into steel-on-steel types that are suitable for applications where there are alternate loas or shock loas, an maintenance-free types which require no lubrication. Seals for Neele Roller earings Seals for Neele Roller earings have a low sectional height an consist of a sheet metal ring an special synthetic rubber. s these seals are manufacture to the same sectional height as Neele Roller earings, grease leakage an the penetration of foreign particles can be effectively prevente by fitting them irectly to the sies of combinable bearings. Spherical Sliing earing Page 1 omponent Part Page 1 POs POs are compact self-aligning spherical plain bushings which can support a large raial loa an a biirectional axial loa at the same time. PO Ro ns have either a female threa in the boy or a male threa on the boy, so they can be easily assemble onto machines. POs are use in control an link mechanisms in machine tools, textile machines, packaging machines, etc. ir-clips for Neele Roller earings ir-clips for Neele Roller earings have been specially esigne for neele roller bearings on which, in many cases, generally available ir-clips cannot be use. They have a low sectional height an are very rigi. There are ir-clips for shafts an for bores, an they are use for positioning to prevent bearing movement in the axial irection. Spherical Sliing earing Page omponent Part Page 1 -alls Neele Rollers -alls are self-aligning ro-ens consisting of a special zinc ie-cast alloy boy an a stue ball which has its axis at right-angles to the boy. They can perform tilting movement an rotation with low torque, an transmit power smoothly ue to the uniform clearance between the sliing surfaces. They are use in link mechanisms in automobiles, construction machinery, farm an packaging machines, etc. Neele Rollers are use for neele roller bearings an are rigi an highly accurate. These neele rollers are wiely use as rolling elements for bearings, an also as pins an shafts. Spherical Sliing earing Page omponent Part Page 1
eatures eatures of of earings earings earing series earing series ppearance ppearance irection of motion irection oa irection of oa llowable irection llowable an motion capacity an rotational capacity speerotational riction spee riction Sectional height Sectional Reference height page Reference page earing series ppearance irection of motion oa irection an capacity llowable rotational spee riction Sectional height Reference page age type age type Neele roller bearings Shell Type Shell Type Neele Roller Neele Roller earings earings ull ull complement complement type type 1 1 Thrust earings Roller bearings 1 or or general usageneral usage 1 1 With thrust ball bearing Neele Neele Roller ages Roller ages or engine or engine connecting connecting ros ros age type age type achine Type achine Type Neele Roller Neele Roller earings earings ull ull complement complement type type 1 1 1 1 ombine Type Neele Roller earings With thrust roller bearing With angular contact ball bearing With three-point contact ball bearing 1 Neele Roller Neele Roller earings with earings age with type age type Separable age Separable age age type age type age type am ollowers ull complement type 1 ull ull Roller earings Roller earings complement complement type type 1 1 Separable cage type or sheavesor sheaves Roller ollowers Non-separable cage type Symbol Symbol Rotation Oscillating Rotation motion Oscillating Raial motion loa Raial xial loa ight xial loa loa eium ight loa loa eium eavy loa specially eavy excellent loa specially excellent xcellent xcellent Normal Normal Non-separable full complement type 1 1
eatures eatures of of earings earings earing series earing series rosse rosse ull ull complement complement Roller earings Roller earings type type Spherical ushings Spherical ushings age type, age type, Separator type Separator type Slim type Slim type Steel-on-steel Steel-on-steel type type aintenance-free aintenance-free type type nsert type, nsert type, ubrication type ubrication type ie-casting type, ie-casting type, POs POs ubrication type ubrication type aintenance-free aintenance-free type type ppearance ppearance irection of motion irection oa irection of oa llowable irection llowable an motion capacity an rotational capacity speerotational riction spee riction Sectional height Sectional Reference height page 1 1 Reference page 1 1 Outline Outline of earing of earing Selection Selection earings are earings available are in available many types in many an types sizes. an To sizes. obtain To satisfactory obtain satisfactory bearing performance bearing performance in machines machines an an equipment, equipment, it is essential it is to essential select the to select most suitable the most bearing suitable by bearing carefully by stuying carefully the stuying requirements the requirements for the application. for the application. lthough there lthough is no there particular is no proceure particular proceure or rule for or bearing rule for selection, bearing an selection, example an of example a commonly of a commonly aopte proceure aopte proceure is shown in is the shown figure in below. the figure below. n example of proceure for bearing selection 1 1 onfirmation onfirmation of of requirements requirements an an operating operating conitions conitions Selection Selection of bearing of bearing type type Selection Selection of of bearing bearing imensions imensions Selection Selection of of accuracy accuracy class, etc. class, etc. Selection Selection of of raial clearance raial clearance an fit an fit entify the machine entify the an machine place where an place the bearing where is the to bearing use. is to be use. onfirm the onfirm requirements the requirements for bearings for such bearings as require such as bearing require bearing performance, performance, an also confirm an also the confirm operating the conitions operating an conitions special an special environment environment conitions. conitions. Select the bearing Select the type bearing suitable type for suitable the operating for the operating conitions by conitions consiering by consiering loa irection loa an irection magni- an magni- See page tue, rigiity, tue, friction, rigiity, allowable friction, rotational allowable spee, rotational bearing spee, bearing space, etc. space, etc. Select the Select bearing imensions the bearing by imensions calculating by bearing calculating bearing loa, life, static loa, safety life, static factor, safety etc. factor, etc. See page 1 Select the Select accuracy the as accuracy require as by require the machine by the or machine or equipment. equipment. See page Select the Select raial the clearance raial consiering clearance consiering the fit, the fit, temperature, temperature, rotational spee, rotational inclination spee, of inclination the inner of the See inner page an outer rings, an etc. outer rings, etc. etermination etermination of bearing of bearing imensions, imensions, accuracy, accuracy, raial clearance raial clearance an fit an fit See page See page 1 See page See page -alls -allsubrication type ubrication type Selection Selection of of lubrication lubrication an an ust-proof ust-proof methos methos Select oil Select or grease oil lubrication. or grease lubrication. fter selection fter of selection lubricant, of in lubricant, case of oil in lubrication, case of oil lubrication, See page select the oil select application the oil metho. application metho. Select the Select sealing metho the sealing accoring metho to accoring the lubricant. to the lubricant. See page Symbol Symbol Rotation Oscillating Rotation motion Oscillating Raial motion loa Raial xial loa ight xial loa loa eium ight loa loa eium eavy loa specially eavy excellent loa specially excellent xcellent xcellent Normal Normal esign of esign of surrouning surrouning part part esign the esign surrouning the surrouning part base on part how base to mount on how to mount or ismount or an ismount base on an mounting base imensions. mounting imensions. See page See page etermination etermination of final specifications of final specifications of the bearing of the bearing an the an surrouning the surrouning part part 1 1
asic ynamic oa Rating an ife ife Rolling bearings will suffer amage ue to various causes uring service. amage such as abnormal wear, seizure, an cracks is cause by improper use, incluing incorrect mounting, lack of oil, ust intrusion an so on, an can be avoie by remeying these causes. owever, bearings will eventually be amage ue to fatigue-flaking even if use properly. When a bearing rotates uner loa, the raceways an the rolling elements are subjecte to repeate stresses concentrate on the part close to the surface. atigue, therefore, occurs in the surface layer, proucing amage in the form of scaling. This is calle flaking (spalling). When this occurs, the bearing can no longer be use. asic rating life The basic rating life is efine as the total number of revolutions that % of a group of ientical bearings can be operate iniviually uner the same conitions free from any material amage cause by rolling fatigue. or rotation at a constant rotational spee, the basic rating life can be represente by the total service hours. asic ynamic loa rating The basic ynamic loa rating is efine as the constant raial loa (in the case of raial bearings) or the constant axial loa acting along the bearing central axis (in the case of thrust bearings) that allows a basic rating life of 1,, revolutions. alculation of rating life Roller bearings 1 1 1 1 Rotational spee rpm 1 1 1 1 nfn Velocity factor 1. 1. 1. 1.1...........1.1.1.1.1 1. 1.. 1 1 asic rating life represente by service hours h ife factor all bearings 1 1 1 1 Rotational spee rpm 1 1 1 1 nfn Velocity factor 1. 1. 1. 1.1...........1.1.1.1.. 1. 1...1 1 1 asic rating life represente by service hours h ife factor h fh h fh.... 1.1 1. 1. 1. 1. 1. 1. 1. 1.. 1..... ig. Scales for rating life calculation..... 1.1 1. 1. 1. 1. 1. 1. 1. 1..... 1...... earing ife earing life is efine as the total number of revolutions (or total service hours at a constant rotational spee) before a sign of the first flaking appears on the rolling surface of raceway or rolling elements. owever, even when bearings of the same size, structure, material an heat treatment are subjecte to the same conitions, the bearing lives will show variation (See ig. 1.). This results from the statistical nature of the fatigue phenomenon. n selecting a bearing, it is incorrect to take an average life for all bearings as the esign stanar. t is more practical to consier a bearing life that is reliable for the greater proportion of bearings use. Therefore, the basic rating life efine in the following is use. ailure probability ensity (requency of failure) asic rating life verage life The relationship among the basic rating life, basic ynamic loa rating an ynamic equivalent loa (bearing loa) of rolling bearings is as follows: ( P ) p 1 = (1) where, 1 :asic rating life, 1 rev. :asic ynamic loa rating, N P :ynamic equivalent loa, N p : xponent, Roller bearing: 1/ all bearing: ccoringly, when the rotational spee per minute is given, the basic rating life is represente as the total service hours accoring to the following equations: 1 1 p h = = f n h () f h = f n () P. f n = ( () n ) 1/p where, h :asic rating life represente by service hours, h n :Rotation spee, rpm f h :ife factor f n :Velocity factor n aition, the rating life can be calculate by obtaining f h an f n from the life calculation scales of ig.. earing life factors for various machines The require life of the bearing must be etermine accoring to the machine in which the bearing is to be use an the operating conitions. Table 1 shows reference values of life factors for selecting a bearing for each machine. Table 1 ife factor of bearings f h for various machines Operating conitions Occasional or short term usage Power tools gricultural machines nfrequent usage but requiring reliable operation ntermittent operation but for comparatively long perios Operate in excess of hours per ay or continuously for an extene time ontinuous use for hours an acciental stops not allowe achine an life factor f h onstruction machinery onveyors levators Roll neck of rolling mills Small motors eck cranes eneral cargo cranes Passenger cars actory motors achine tools eneral gear units Printing machines scalators entrifugal separators lowers Woo working machines Plastic extruing machines rane sheaves ompressors mportant gear units Paper making machines Water supply equipment Power station equipment Rolling fatigue life ig. 1 Variation of rolling fatigue life 1 1N=.1kgf=.lbs. 1mm=.inch 1
ife of oscillating bearing The life of an oscillating bearing can be obtaine from equation (). O = () ( P ) p θ where, O : asic rating life of oscillating bearing, 1 cycles θ :Oscillating angle, eg. (See ig.) P :ynamic equivalent loa, N Therefore, when the oscillating frequency n 1 cpm is given, the basic rating life as represente by total oscillating hours can be obtaine by substituting n 1 for n in equation () on page 1. When θ is small, an oil film cannot be forme easily between the contact surfaces of the raceway an the rolling elements. This may cause fretting corrosion. n this case, please consult. orrecte rating life ig. Oscillating motion When a rolling bearing is use in orinary applications, the basic rating life can be calculate by equations (1) an () mentione previously. This basic rating life applies to bearings which require a reliability of %, have orinary bearing properties being mae of materials of orinary quality for rolling bearings, an are use uner orinary operating conitions. n some applications, however, it is necessary to obtain a rating life that applies to bearings which require high reliability, have special bearing properties or are use uner special operating conitions. The correcte rating life for these special cases can be obtaine from the following equation by using the bearing life ajustment factors a 1, a an a, respectively. na = a 1 a a 1 () where, na :orrecte rating life, 1 rev. a 1 :ife ajustment factor for reliability a : ife ajustment factor for special bearing properties a :ife ajustment factor for operating conitions ife ajustment factor for reliability a 1 The reliability of rolling bearings is efine as the proportion of bearings having a life equal to or greater than a certain specifie value when a group of ientical bearings are operate uner ientical conitions. With respect to iniviual bearings, it refers to the probability of the life of a bearing being equal to or greater than a certain specifie value. The correcte rating life for a reliability of (1-n)% can be obtaine using equation (). Table shows the values of the life ajustment factor a 1 for various reliabilities. Table ife ajustment factor for reliability a 1 Reliability % n a 1 1 1 1.....1 ife ajustment factor for special bearing properties a The bearing life is extene or shortene accoring to the quality of the material, the manufacturing technology of the bearing an its internal esign. or these special bearing life properties, the life is correcte by the life ajustment factor for special bearing properties a. The table of imensions for earings shows the values of the basic ynamic loa rating which are etermine taking into consieration the fact that bearing life has been extene by improve quality of materials an avances in manufacturing technologies. Therefore, the bearing life is calculate using equation () usually assuming a = 1. ife ajustment factor for operating conitions a This factor helps take into account the effects of operating conitions, especially lubrication on the bearing. The bearing life is limite by the phenomenon of fatigue which occurs, in general, beneath surfaces subjecte to repeate stresses. Uner goo lubrication conitions where the rolling element an raceway surfaces are completely separate by an oil film an surface amage can be isregare, a is set to be 1. owever, when conitions of lubrication are not goo, namely, when the viscosity of the lubricating oil is low or the peripheral spee of the rolling elements is especially low, an so on, a < 1 is use. On the other han, when lubrication is especially goo, a value of a > 1 can be use. When lubrication is not goo an a < 1 is use, the life ajustment factor a cannot generally excee 1. When selecting a bearing accoring to the basic ynamic loa rating, it is recommene that a suitable value for reliability factor a 1 is chosen for each application. The selection shoul be mae using the (/P) or f h values etermine by machine type an base upon the actual conitions of lubrication, temperature, mounting, etc., which have alreay been experience an observe in the same type of machines. imiting conitions These bearing life equations are applicable only when the bearing is mounte an lubricate normally without intrusion of foreign materials an not use uner extreme operating conitions. Unless these conitions are satisfie, the life may be shortene. or example, it is necessary to separately consier the effects of bearing mounting errors, excessive eformation of housing an shaft, centrifugal force acting on rolling elements at high-spee revolution, excessive preloa, especially large raial internal clearance of raial bearings, etc. When the ynamic equivalent loa excees 1/ of the basic ynamic loa rating, the life equations may not be applicable. orrection of basic ynamic loa rating for temperature an harness Temperature factor The operating temperature for each bearing is etermine accoring to its material an structure. f special heat treatment is performe, bearings can be use at temperatures higher than +1. s the allowable contact stress graually ecreases when the bearing temperature excees 1, the basic ynamic loa rating is lowere an can be obtaine by the following equation: t = f t () where, t : asic ynamic loa rating consiering temperature rise, N f t : Temperature factor (See ig..) : asic ynamic loa rating, N Temperature 1 ft 1.... ig. Temperature factor.. urther, if the bearing is use at high temperature, i.e. 1 or above, the amount of imensional isplacement gets larger. So special heat treatment is necessary. f neee, please contact. arness factor When the shaft or housing is use as the raceway surface instea of the inner or outer ring, the surface harness of the part use as the raceway surface shoul be R. f it is less than R, the basic ynamic loa rating is lowere an can be obtaine by the following equation: = f () where, :asic ynamic loa rating consiering harness, N f :arness factor (See ig..) :asic ynamic loa rating N arness of raceway surface R f 1.....1 ig. arness factor 1 1N=.1kgf=.lbs. 1mm=.inch
asic Static oa Rating an Static Safety actor asic static loa rating When a bearing at rest sustains a heavy loa or a bearing rotating at a relatively low spee receives a heavy shock loa, the contact stress may excee a certain limiting value, proucing a local permanent eformation in the raceways or the rolling elements, an subsequently causing noise or vibration or lowering the rotating performance. The basic static loa rating is, therefore, etermine as a guieline for the maximum allowable loa for the bearing at rest, uner which the permanent eformation will not excee a certain limit value, an the lowering of the rotating performance will not occur. ts efinition is given as follows. The basic static loa rating is the static loa that gives the contact stress shown in Table at the center of the contact area of the rolling element an the raceway receiving the maximum loa. raial loa constant in irection an magnitue is use in the case of raial bearings, while an axial loa constant in magnitue acting along the bearing central axis is use in the case of thrust bearings. Table Static safety factor The basic static loa rating gives the theoretical allowable limit of the static equivalent loa. Normally, this limit is correcte by consiering the operating conitions an the requirements for the bearing. The correction factor, namely, the static safety factor f s is efine as in the following equation an its general values are shown in Table. f s = () P where, : asic static loa rating, N P : Static equivalent loa, N Table Static safety factor Operating conitions of the bearing When high rotational accuracy is require or orinary operation conitions or orinary operation conitions not requiring very smooth rotation When there is almost no rotation 1. 1 n case of Shell Type Neele Roller earings of which outer ring is rawn from a thin steel plate an then carburize an quenche, it is necessary to use a static safety factor of or more. f s alculation of earing oas The loas acting on bearings inclue the weight of the machine parts supporte by the bearings, the weight of the rotating boy, loas prouce when operating the machine, loas by belts or gears transmitting power, an various other loas. These loas can be ivie into raial loas perpenicular to the central axis of the bearings an axial loas parallel to the central axis, an they act inepenently or in combination with other loas. n aition, the magnitue of vibration or shocks on the bearings varies epening on the application of the machine. Thus, theoretically calculate loas may not always be accurate an have to be correcte by multiplying various empirical factors to obtain the actual bearing loas. oa istribution to bearings Table shows examples of calculations where static loas are acting in raial irection. oa factor lthough raial loas an axial loas can be obtaine by calculation, it is not unusual for the actual bearing loas to excee the calculate loas, ue to vibration an shocks prouce when operating the machine. The actual bearing loa is obtaine from the following equation, by multiplying the calculate loa by the loa factor: = f w c (1) where, :earing loa, N f w :oa factor (See Table.) c :Theoretically calculate loa, N Table oa factor Operating conitions xample f w Smooth operation without shocks Orinary operation Operation subjecte to vibration an shocks lectric motors, ir conitioning equipment, easuring instruments, achine tools Reuction gearboxes, Vehicles, Textile machinery, Paper making machinery Rolling mills, Rock crushers, onstruction machinery 1 1. 1. 1. 1. Type of bearing Roller bearings Self-aligning ball bearings Other ball bearings ontact stress Pa Table oa istribution to bearings a xample b r1 = earing loa r1 + b r f r1 c r1 r r r = c r1 + a r f f a b c r1 r r r1 r r1 = r = g r1 + b r c r f a r + r e r1 f e g f 1 1N=.1kgf=.lbs. 1mm=.inch
earing loas in case of belt or chain transmission When power is transmitte by a belt or chain, the loa acting on the pulley or sprocket wheel is obtaine from the following equations: T= n () T t = (1) R where, T : Torque acting on pulley or sprocket wheel, N-mm t :ffective transmitting force of belt or chain, N :Transmitting power, kw n :Rotation spee, rpm R : ffective raius of pulley or sprocket wheel, mm or belt transmission, the loa r acting on the pulley shaft is obtaine from the following equation, multiplying the effective transmitting force t by the belt factor f b shown in Table. r =f b t (1) T= n (1) t = (1) s = t tan θ (1) c= t + s = t sec θ (1) where, T R T :Torque applie to gear, N-mm t:tangential force acting on gear, N s:raial force acting on gear, N c:resultant normal force on gear tooth surface, N :Transmitting power, kw n :Rotational spee, rpm R :Pitch circle raius of rive gear, mm θ:pressure angle of gear, eg. s t R ean equivalent loa corresponing to fluctuating loa When the loa applie to the bearing fluctuates, the bearing life is calculate by using the mean equivalent loa m, which is a constant loa that will give the bearing a life equal to that prouce uner the fluctuating loa. The mean equivalent loa is obtaine from the following equation: Table ean equivalent loa for the fluctuation loa Step loa Type of fluctuating loa N1 1 N N Nn n m m = p N 1 (1) p n N N where, m :ean equivalent loa, N N :Total number of revolutions, rev. n :luctuating loa, N p : xponent, Roller bearing = 1/ all bearing = Table shows examples of the calculation of mean equivalent loas for various fluctuating loas. ean equivalent loa m p m = 1 p p p ( 1 N 1 + N + + n N n ) N where, N 1 :Total number of revolutions uner loa 1 rev. N :Total number of revolutions uner loa rev. N n :Total number of revolutions uner loa n rev. p Table elt factor Type of belt V-belts Timing belts Plain belts (with tension pulley) Plain belts f b. 1.. n the case of chain transmission, a value of 1. to 1. is taken as the chain factor corresponing to f b. The loa acting on the sprocket wheel shaft is obtaine from equation (1) in the same manner as the belt transmission. earing loas in case of gear transmission ig. n this case, the resultant normal force on the tooth surface acts as the raial force to the shaft an the magnitue of vibration or shocks varies epening on the accuracy an surface finish of the gear. Therefore, the raial loa r applie to the shaft is obtaine from the following equation, multiplying the resultant normal force c on gear tooth surface by the gear factor f z shown in Table. r =f z c (1) onotonously changing loa Sinusoially fluctuating loa min max N max N max m m N m 1 m = ( max + min ) where, max :aximum value of fluctuating loa, N min :inimum value of fluctuating loa, N m. max m. max When power is transmitte by gears, the force acting on the gears varies accoring to the type of gear. Spur gears prouce raial loas only, but helical gears, bevel gears an worm gears prouce axial loas in aition to raial loas. Taking the simplest case of spur gears as an example, the bearing loa is obtaine from the following equations: Table ear factor Type of gear Precision gears (Pitch error an form error: ess than.mm) Orinary machine gears (Pitch error an form error:..1mm) f z 1. 1.1 1.1 1. Stationary loa plus rotating loa s R m = S + R S R S + R where, S :Stationary loa, N R :Rotating loa, N 1N=.1kgf=.lbs. 1mm=.inch
quivalent loa The loas applie to the bearing are ivie into raial loas that are applie perpenicular to the central axis an axial loas that are applie in parallel to the central axis. These loas act inepenently or in combination with other loas. ynamic equivalent loa When both raial loa an axial loa are applie to the bearing simultaneously, the virtual loa, acting on the center of the bearing, that will give a life equal to that uner the raial loa an the axial loa is efine as a ynamic equivalent loa. n the case of neele roller bearings, raial bearings receive only raial loas an thrust bearings receive only axial loas. ccoringly, raial loas are irectly use in the life calculation of the raial bearings, while axial loas are irectly use for the thrust bearings. [or raial bearings] P r = r () [or thrust bearings] P a = a (1) where, P r :ynamic equivalent raial loa, N P a :ynamic equivalent axial loa, N r :Raial loa, N a :xial loa, N Static equivalent loa When both raial loa an axial loa are applie to the bearing simultaneously, the virtual loa, acting on the center of the bearing, that will prouce a maximum contact stress on the contact surface between the rolling element an the raceway equal to that given by the raial loa an the axial loa is efine as a static equivalent loa. n the case of neele roller bearings, raial bearings receive only raial loas an thrust bearings receive only axial loas. ccoringly, raial loas are irectly use for the raial bearings, while axial loas are irectly use for the thrust bearings. [or raial bearings] P r = r () [or thrust bearings] P a = a () where, P r :Static equivalent raial loa, N P a :Static equivalent axial loa, N r :Raial loa, N a :xial loa, N ounary imensions an entification Number ounary imensions xamples of symbols for quantities inicating the bounary imensions of Neele Roller earings are shown below. or etails, see the table of imensions for each moel. achine Type Neele Roller earing :Nominal bearing bore iameter :Nominal bearing outsie iameter :Nominal inner ring with :Nominal outer ring with w :Nominal roller set bore iameter r :hamfer imensions of inner an outer rings r s min :Smallest permissible single chamfer imensions of inner an outer rings r r r r w Neele Roller age w :Nominal roller set outsie iameter w :Nominal roller set bore iameter c :Nominal cage with w Thrust Roller earing c ig. Neele Roller age c :Nominal cage outsie iameter c :Nominal cage bore iameter w :Nominal roller iameter w w ig. achine Type Neele Roller earing Shell Type Neele Roller earing c c :Nominal bearing outsie iameter w :Nominal roller set bore iameter :Nominal outer ring with ig. 1 Thrust Roller earing w ig. Shell Type Neele Roller earing 1N=.1kgf=.lbs. 1mm=.inch
entification Number age symbol lassification symbol The ientification number of earings consists of a moel number an supplemental coes. The escriptions of typical coes an their arrangements are shown below. There are many coes other than those escribe. See the section of ientification number of each bearing. Table 1 rrangement of ientification number of bearing oel number Supplemental coe oel coe ounary imensions aterial symbol age symbol Shiel symbol Seal symbol, earing ring shape symbol learance symbol lassification symbol 1 oel coe The moel coe represents the bearing series. The features of each bearing series are shown on pages to 1. ounary imensions One of the following four kins of presentation methos is use for showing bounary imensions in the ientification number, which vary epening on the bearing series. Table shows the presentation methos of bounary imensions for each moel coe. (a)imension series + ore iameter number (b) ore iameter or roller set bore iameter + Outsie iameter or roller set outsie iameter + With (c)ore iameter or roller set bore iameter + With ()asic iameter aterial symbol Symbol Type of material Stainless steel for bearing rings an rolling elements 1 Symbol N V Seal or shiel symbol Symbol Z ZZ U UU RS escriptions ae of synthetic resin No cage or full complement With ust cover escriptions With shiels on both sies With a seal on one sie With seals on both sies With seals on both sies earing ring shape symbol Symbol NR O( 1 ) With stop ring on outer surface of outer ring With oil hole in bearing ring No oil hole escriptions Note( 1 ) This iffers epening on the type of bearing. See the section of each bearing. learance symbol Symbol (None) T1 1 clearance N clearance clearance clearance clearance escriptions Special raial clearance (pplicable to rosse Roller earings) Symbol escriptions (None) S lass P S lass P S lass P S lass Table nication of bounary imensions earing type oel coe T,T,YT,YT Shell Type Neele Roller earings,,y,y Neele Roller ages for eneral Usage T,TW Neele Roller ages for ngine onnecting Ros T,TV N,RN TR,T,TR achine Type Neele Roller earings TR,T,TR R,R R,R RN,RNW Neele Roller earings with Separable age N,NW NU,N,NS Roller earings TRU NT,S,WS,S Thrust earings Z Z NX,NX ombine Type Neele Roller earings NX,NX NT,NT,NU,S am ollowers R R,R Roller ollowers NST,NRT,NURT RY rosse Roller earings R,R,RS,RT S, Spherical ushings S POs P,PS,POS,PS,POS,PS -alls S,S Seals for Neele Roller earings OS,S WR ir-clips for Neele Roller earings R oel number Note( 1 ) The nominal imensions of inch series bearings are inicate in units of 1/1 inch. nication of bounary imensions Roller set bore iameter + Outer ring with Roller set bore iameter + Outer ring with ( 1 ) Roller set bore iameter + Roller set outsie iameter + age with Roller set bore iameter + Roller set outsie iameter + age with imension series + ore iameter number Roller set bore iameter + earing outsie iameter + earing with earing bore iameter + earing outsie iameter + Outer ring with Roller set bore iameter + earing outsie iameter + earing with ( 1 ) earing bore iameter + earing outsie iameter + Outer ring with ( 1 ) Roller set bore iameter + earing outsie iameter + earing with earing bore iameter + earing outsie iameter + earing with imension series + ore iameter number earing bore iameter + earing outsie iameter + earing with earing bore iameter + earing outsie iameter earing bore iameter + earing outsie iameter + earing height earing bore iameter + earing outsie iameter + Roller iameter Roller set bore iameter + ssemble bearing with nnerring bore iameter + ssemble bearing with imensional series + ore iameter number Stu iameter earing outsie iameter earing outsie iameter ( 1 ) earing bore iameter earing outsie iameter ( 1 ) earing bore iameter + earing with nner ring bore iameter nner ring bore iameter ( 1 ) nner ring bore iameter Screw size Shaft iameter + Seal outsie iameter + Seal with Shaft iameter ore iameter 1N=.1kgf=.lbs. 1mm=.inch
xample of ientification number ccuracy (a) xample of "imension series + ore iameter number" oel coe imension series ore iameter number learance symbol lassification symbol oel coe oel number N P (c) xample of "ore iameter or roller set bore iameter + with" oel number Supplemental coe Supplemental coe NX Z (b) xample of "ore iameter or roller set bore iameter + Outsie iameter or roller set outsie iameter + with" oel coe Roller set bore iameter Roller set outsie iameter age with age symbol () xample of "asic iameter" oel coe oel number T N oel number Supplemental coe Supplemental coe 1 V UU The accuracy of Neele Roller earings conforms to S -1~- (Rolling bearings - Tolerances of bearings), an the imensional accuracy an rotational accuracy are specifie. The specifie items are shown in ig.. Neele Roller earings are classifie into classes of accuracy. These classes are represente by the numbers,, an, written in orer of increasing accuracy. Table 1 shows the accuracy for the inner rings of raial bearings, Table 1 shows the accuracy for the outer rings of raial bearings, Table 1 shows the tolerances for the smallest single roller set bore iameter of raial bearings, an Table 1 shows the permissible limit values of chamfer imensions of raial bearings. or thrust bearings, see the section on accuracy of Thrust earings. Note that the series of Shell Type Neele Roller earings, Roller earings, am ollowers, Roller ollowers, ombine Type Neele Roller earings, an rosse Roller earings have special accuracy. or further etails, see the section on accuracy of each bearing series. Remarks The meanings of the new symbols for quantities use for accuracy of raial bearings are as follows: 1 represents the eviation of a imension from the specifie value. V represents the variation of a imension. Suffixes s, m, an p represent a single (or actual) measurement, a mean measurement, an a measurement in a single raial plane, respectively. [xample] V p means the ifference between the largest an the smallest of the bore iameters in a single raial plane (circularity). V mp means the ifference between the largest an the smallest of the single plane mean bore iameters (cylinricity). Single bore iameter eviation s Roller set bore iameter ssemble bearing with Shiel symbol asic iameter (Stu iameter) age symbol Shape of stu hea eviation of bounary imensions Single plane mean bore iameter eviation mp Single outsie iameter eviation s Single plane mean outsie iameter eviation mp eviation of a single inner ring with s Seal symbol ccuracy of bounary imensions eviation of a single outer ring with s ore iameter variation in a single raial plane V sp ean bore iameter variation V mp Variation of bounary imensions Outsie iameter variation in a single raial plane V sp ean outsie iameter variation V mp ccuracy of bearings nner ring with variation V s Outer ring with variation V s Raial runout of assemble bearing inner ring ia ssemble bearing inner ring face runout with raceway S ia Rotational accuracy nner ring reference face runout with bore S Raial runout of assemble bearing outer ring ea ssemble bearing outer ring face runout with raceway S ea Variation of outsie surface generatrix inclination with outer ring reference face S ig. ccuracy of bearings
Table 1 Tolerances for inner ring Nominal bearing bore iameter mp Single plane mean bore iameter eviation s Single bore iameter eviation V sp ore iameter variation in a single raial plane iameter series, (1) iameter series () V mp ean bore iameter variation lass lass lass lass lass lass lass lass lass lass lass lass mm lass lass lass lass lass Over ncl. igh ow igh ow igh ow igh ow igh ow ax. ax. ax.. 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 - - - 1-1 - 1 - - - - - - - - - 1-1 - 1 - - - - - 1-1 - 1-1 - - - - - Note( 1 ) pplicable to all series except NS series ( ) pplicable to NS series ( ) pplicable to NT an NT series - - - - - - 1-1 - 1-1 - - - - - - - - 1-1 - - - - - - - 1-1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1.. ia Raial runout of assemble bearing inner ring lass 1 1 1 1 1 1 1 lass lass ax. 1 1 1 1 1 1 1 lass.. S S ia () nner ring ssemble bearing reference face inner ring face runout with bore runout with raceway s eviation of a single inner ring with V s nner ring with variation lass lass lass lass lass lass lass lass lass lass lass ax. ax. igh ow igh ow igh ow igh ow ax. 1 1 1 1 1 1-1 - 1-1 - 1-1 - - - - - - - - - 1-1 - 1 - - 1-1 - 1-1 - 1 - - - - - - - - - - 1-1 - 1 - - - - - - - - 1-1 - 1 - - - 1 1 1 1 1 1 1 1 lass... Nominal bearing bore iameter mm Over. 1 1 1 1 1 1 1 1 unit: μ m ncl. 1 1 1 1 1 1 1 1 Table 1 Tolerances for outer ring Nominal bearing outsie iameter mp Single plane mean outsie iameter eviation s Single outsie iameter eviation V sp (1) Outsie iameter variation in a single raial plane Open bearing earing with seal or shiel iameter series, () iameter series () iameter series () mm lass lass lass lass lass lass lass lass lass lass lass lass lass lass Over ncl. igh ow igh ow igh ow igh ow igh ow ax. ax. ax.. 1 1 1 1 1 1 1 1 1 1 1 - - - - - 1-1 - 1 - - - - - - - - 1 - - - - - - 1-1 - 1 - - - - - - - - - - - - - 1 - - 1-1 - 1 - - - - - - - - - - - - 1 - - 1-1 - - - - - - - - 1 - - 1-1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 lass 1 1 1 V mp ean outsie iameter variation lass lass ax. 1 1 1 1 1 1 1 1 1 lass.. lass ea Raial runout of assemble bearing outer ring 1 1 1 1 1 1 S Variation of outsie surface generatrix inclination with outer ring reference face S ea () ssemble bearing outer ring face runout with raceway s eviation of a single outer ring with V s Outer ring with variation lass lass lass lass lass lass lass lass,,, lass lass lass lass ax. ax. ax. igh ow ax. 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Same as the tolerance values of s for of the same bearing Same as the tolerance values of V s for of the same bearing 1 1 1 1.... Nominal bearing outsie iameter Over. 1 1 1 1 1 mm unit: μ m ncl. 1 1 1 1 1 1 1 1 1 1 1-1 - 1 - - Note( 1 ) lasses an are applicable to outer rings without stop rings. ( ) pplicable to all series except NS series ( ) pplicable to NS series ( ) pplicable to NT an NT series 1 1 1 1 1 1 1 1 1N=.1kgf=.lbs. 1mm=.inch