corporation Ball and Roller Bearings

Transcript

1 Fo New Technology Netwok R copoation Ball and Rolle Beaings (

2 Technical Data A- Deep Goove Ball Beaings B- Miniatue and Exta Small Beaings B- 1 Angula Contact Ball Beaings B- Self-Aligning Ball Beaings B- Cylindical Rolle Beaings B- 77 Tapeed Rolle Beaings B-119 Spheical Rolle Beaings B-219 Thust Beaings B-2 Locknuts, Lockwashes & Lockplates C- 1 Catalog List & Appendix Table D- 1

3 Waanty NTN waants, to the oiginal puchase only, that the deliveed poduct which is the subject of this sale (a) will confom to dawings and specifications mutually established in witing as applicable to the contact, and (b) be fee fom defects in mateial o fabication. The duation of this waanty is one yea fom date of delivey. If the buye discoves within this peiod a failue of the poduct to confom to dawings o specifications, o a defect in mateial o fabication, it must pomptly notify NTN in witing. In no event shall such notification be eceived by NTN late than 1 months fom the date of delivey. Within a easonable time afte such notification, NTN will, at its option, (a) coect any failue of the poduct to confom to dawings, specifications o any defect in mateial o wokmanship, with eithe eplacement o epai of the poduct, o (b) efund, in pat o in whole, the puchase pice. Such eplacement and epai, excluding chages fo labo, is at NTN's expense. All waanty sevice will be pefomed at sevice centes designated by NTN. These emedies ae the puchase's exclusive emedies fo beach of waanty. NTN does not waant (a) any poduct, components o pats not manufactued by NTN, (b) defects caused by failue to povide a suitable installation envionment fo the poduct, (c) damage caused by use of the poduct fo puposes othe than those fo which it was designed, (d) damage caused by disastes such as fie, flood, wind, and lightning, (e) damage caused by unauthoized attachments o modification, (f) damage duing shipment, o (g) any othe abuse o misuse by the puchase. THE FOREGOING WARRANTIES ARE IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. In no case shall NTN be liable fo any special, incidental, o consequential damages based upon beach of waanty, beach of contact, negligence, stict tot, o any othe legal theoy,and in no case shall total liability of NTN exceed the puchase pice of the pat upon which such liability is based. Such damages include, but ae not limited to, loss of pofits, loss of savings o evenue, loss of use of the poduct o any associated equipment, cost of capital, cost of any substitute equipment, facilities o sevices, downtime, the claims of thid paties including customes, and injuy to popety. Some states do not allow limits on waanties, o on emedies fo beach in cetain tansactions. In such states, the limits in this paagaph and in paagaph (2) shall apply to the extent allowable unde case law and statutes in such states. Any action fo beach of waanty o any othe legal theoy must be commenced within 1 months following delivey of the goods. Unless modified in a witing signed by both paties, this ageement is undestood to be the complete and exclusive ageement between the paties, supeceding all pio ageements, oal o witten, and all othe communications between the paties elating to the subject matte of this ageement. No employee of NTN o any othe paty is authoized to make any waanty in addition to those made in this ageement. This ageement allocates the isks of poduct failue between NTN and the puchase. This allocation is ecognized by both paties and is eflected in the pice of the goods. The puchase acknowledges that it has ead this ageement, undestands it, and is bound by its tems. NTN Copoation. 29 Although cae has been taken to assue the accuacy of the data compiled in this catalog, NTN does not assume any liability to any company o peson fo eos o omissions.

4 Ball and Rolle Beaings CAD data of model numbes given in the catalog is available as an electonic catalog. Fo infomation, please contact NTN Engineeing.

5 TECHNICAL DATA CONTENTS 1. Classification and Chaacteistics of Rolling Beaings A- 1.1 Rolling beaing constuction A- 1.2 Classification of olling beaings A- 1. Chaacteistics of olling beaings A-8. Bounday Dimensions and Beaing Numbe Codes A-.1 Bounday dimensions A-.2 Beaing numbes A-1 2. Beaing Selection A Beaing selection flow chat A Type and chaacteistics A-1 2. Selection of beaing aangement A-1. Beaing Toleances A-.1 Dimensional accuacy and unning accuacy A-.2 Chamfe measuements and toleance o allowable values of tapeed boe A-. Beaing toleance measuement methods A-8. Load Rating and Life A-17.1 Beaing life A-17.2 Basic ating life and basic dynamic load ating A-17. Adjusted ating life A-18. Machine applications and equisite life A-19. Basic static load ating A-19. Allowable static equivalent load A-2. Beaing Load Calculation A-21.1 Loads acting on shafts A-21.2 Beaing load distibution A-2. Mean load A-2. Equivalent load A-2. Beaing ating life and load calculation examples A Beaing Fits A Fitting A The necessity of a pope fit A-9 7. Fit selection A-9 8. Beaing Intenal Cleaance and Peload A Beaing intenal cleaance A Intenal cleaance selection A-8 8. Peload A- 9. Allowable Speed A-7 A-2

6 1. Fiction and Tempeatue Rise A Fiction A Tempeatue ise A Lubication A Pupose of lubication A Lubication methods and chaacteistics A Gease lubication A Solid gease (Fo beaings with solid gease) A Oil lubication A Extenal beaing sealing devices A-8 1. Beaing Mateials A Raceway and olling element mateials A Cage mateials A-8 1. Shaft and Housing Design A Fixing of beaings A Beaing fitting dimensions A-8 1. Shaft and housing accuacy A Allowable beaing misalignment A Beaing Handling A Beaing stoage A Installation A Intenal cleaance adjustment A-9 1. Post installation unning test A Beaing disassembly A Beaing maintenance and inspection A-9 1. Beaing Damage and Coective Measues A Technical data A Deep goove ball beaing adial intenal cleaances and axial intenal cleaances A Angula contact ball beaing axial load and axial displacement A Tapeed olle beaing axial load and axial displacement A Allowable axial load fo ball beaings A Fitting suface pessue A Necessay pess fit and pullout foce A-1 A-

7 Classification and Chaacteistics of Rolling Beaings 1. Classification and Chaacteistics of Rolling Beaings 1.1 Rolling beaing constuction Most olling beaings consist of ings with aceway (inne ing and oute ing), olling elements (eithe balls o olles) and cage. The cage sepaates the olling elements at egula intevals, holds them in place within the inne and oute aceways, and allows them to otate feely. Raceway (inne ing and oute ing) o aceway washe 1) The suface on which olling elements oll is called the "aceway suface". The load placed on the beaing is suppoted by this contact suface. Geneally the inne ing fits on the axle o shaft and the oute ing on the housing. Note 1: The aceway of thust beaing is called "aceway washe," the inne ing is called the "shaft aceway washe" and the oute ing is called the "housing aceway washe." Rolling elements Rolling elements classify in two types: balls and olles. Rolles come in fou types: cylindical, needle, tapeed, and spheical. Balls geometically contact with the aceway sufaces of the inne and oute ings at "points", while the contact suface of olles is a "line" contact. Theoetically, olling beaings ae so constucted as to allow the olling elements to otate obitally while also otating on thei own axes at the same time. Cages Cages function to maintain olling elements at a unifom pitch so load is neve applied diectly to the cage and to pevent the olling elements fom falling out when handling the beaing. Types of cages diffe accoding to way they ae manufactued, and include pessed, machined and fomed cages. 1.2 Classification of olling beaings Rolling beaings divide into two main classifications: ball beaings and olle beaings. Ball beaings ae classified accoding to thei beaing ing configuations: deep goove type and angula contact type. Rolle beaings on the othe hand ae classified accoding to the shape of the olles: cylindical, needle, tapeed and spheical. Oute ing Inne ing Cage Ball Deep goove ball beaing Fig A Oute ing Inne ing Cage Rolle Cylindical olle beaing Fig. C Oute ing Rolle Cage Inne ing Tapeed olle beaing Fig. E Oute ing Inne ing Ball Cage Angula contact ball beaing Fig.B Oute ing Rolle Cage Needle olle beaing Fig. D Oute ing Inne ing Rolle Cage Spheical olle beaing Fig. F Rolling beaings can be futhe classified accoding to the diection in which the load is applied; adial beaings cay adial loads and thust beaings cay axial loads. Othe classification methods include: 1) numbe of olling ows (single, double, o -ow), 2) sepaable and non-sepaable, in which eithe the inne ing o the oute ing can be detached. Thee ae also beaings designed fo special applications, such as: ailway ca jounal olle beaings, ball scew suppot beaings, tuntable beaings, as well as linea motion beaings (linea ball beaings, linea olle beaings and linea flat olle beaings).types of olling beaings ae given in Fig Shaft aceway washe Ball Cage Housing aceway washe Thust ball beaing Fig. G Fig. 1.1 Rolling beaing Shaft aceway washe Cage Rolle Housing aceway washe Thust olle beaing Fig. H A-

8 Classification and Chaacteistics of Rolling Beaings Single ow deep goove ball beaings B- Single ow angula contact ball beaings B- Radial ball beaings Duplex angula contact ball beaings B- Fou-point contact ball beaings B-8 Double ow angula contact ball beaings B- Ball beaings Self-aligning ball beaings B- Ball beaings fo olling beaing unit* Single diection thust ball beaings B-2 Thust ball beaings Double diection angula contact thust ball beaings* High-speed duplex angula contact ball beaings (fo axial loads)* Rolling beaings Single ow cylindical olle beaings B- 77 Double ow cylindical olle beaings B-12 Radial olle beaings Needle olle beaings* Single ow tapeed olle beaings B-119 Double ow tapeed olle beaings B-18 Rolle beaings Spheical olle beaings B-219 Cylindical olle thust beaings* Needle olle thust beaings* Thust olle beaings Tapeed olle thust beaings* Spheical olle thust beaings B-22 Fig. 1.2 Classification of olling beaings A-

9 Classification and Chaacteistics of Rolling Beaings Ulta thin wall type ball beaings* Ball scew suppot beaings* Railway ca jounal olle beaings* Ulta-clean vacuum beaings* SL-type cylindical olle beaings* Special application beaings Insulated beaings MEGAOHM TM seies* Rubbe molded beaings* Cleaance adjusting needle olle beaings* Complex beaings* Connecting od needle olle beaings with cage* Rolle followes* Cam followes* Linea motion beaings Linea ball beaings* Linea olle beaings* Linea flat olle beaings* Note: Beaings maked with an asteisk ae not contained in this catalog. Fo details, see the catalog devoted to the concened type of beaing. A-7

10 Classification and Chaacteistics of Rolling Beaings 1. Chaacteistics of olling beaings 1..1 Chaacteistics of olling beaings Rolling beaings come in many shapes and vaieties, each with its own distinctive featues. Howeve, when compaed with sliding beaings, olling beaings all have the following advantages: (1) The stating fiction coefficient is lowe and thee is little diffeence between this and the dynamic fiction coefficient. (2) They ae intenationally standadized, intechangeable and eadily obtainable. () They ae easy to lubicate and consume less lubicant. () As a geneal ule, one beaing can cay both adial and axial loads at the same time. () May be used in eithe high o low tempeatue applications. () Beaing igidity can be impoved by peloading. Constuction, classes, and special featues of olling beaings ae fully descibed in the bounday dimensions and beaing numbeing system section Ball beaings and olle beaings Table 1.1 gives a compaison of ball beaings and olle beaings. 1.. Radial and thust beaings Almost all types of olling beaings can cay both adial and axial loads at the same time. Geneally, beaings with a contact angle of less than have a much geate adial load capacity and ae classed as adial beaings; wheeas beaings which have a contact angle ove have a geate axial load capacity and ae classed as thust beaings. Thee ae also beaings classed as complex beaings which combine the loading chaacteistics of both adial and thust beaings. 1.. Standad beaings and special beaings The bounday dimensions and shapes of beaings confoming to intenational standads ae intechangeable and can be obtained easily and economically ove the wold ove. It is theefoe bette to design mechanical equipment to use standad beaings. Howeve, depending on the type of machine they ae to be used in, and the expected application and function, a non-standad o specially designed beaing may be best to use. Beaings that ae adapted to specific applications, and "unit beaings" which ae integated (built-in) into a machine's components, and othe specially designed beaings ae also available. The featue of typical standad beaings ae as follows: Table 1.1 Compaison of ball beaings and olle beaings Contact with aceway Chaacteistics Load capacity Ball beaings 2a 2b Point contact Contact suface is oval when load is applied. Because of point contact thee is little olling esistance, ball beaings ae suitable fo low toque and high-speed applications. They also have supeio acoustic chaacteistics. Load capacity is lowe fo ball beaings, but adial beaings ae capable of beaing loads in both the adial and axial diection. Rolle beaings 2b Linea contact Contact suface is geneally ectangula when load is applied. Because of linea contact, otational toque is highe fo olle beaings than fo ball beaings, but igidity is also highe. Load capacity is highe fo olling beaings. Cylindical olle beaings equipped with a lip can bea slight adial loads. Combining tapeed olle beaings in pais enables the beaings to bea an axial load in both diections. Deep goove ball beaings The most common type of beaing, deep goove ball beaings ae widely used in a vaiety of fields. Deep goove ball beaings include shield beaings and sealed beaings with gease make them easie to use. Deep goove ball beaings also include beaings with a locating snap-ing to facilitate positioning when mounting the oute ing, expansion compensating beaings which absob dimension vaiation of the beaing fitting suface due to housing tempeatue, and TAB beaings that ae able to withstand contamination in the lubicating oil. Table 1.2 Configuation of sealed ball beaings Type and symbol Configuation Shield Non-contact ZZ Non-contact LLB Sealed Contact LLU Low toque LLH A-8

11 Classification and Chaacteistics of Rolling Beaings Angula contact ball beaings The line that unites point of contact of the inne ing, ball and oute ing uns at a cetain angle (contact angle) in the adial diection. Beaings ae geneally designed with thee contact angles. Angula contact ball beaings can suppot an axial load, but cannot be used by single beaing because of the contact angle. They must instead be used in pais o in combinations. Angula contact ball beaings include double ow angula contact ball beaings fo which the inne and oute ings ae combined as a single unit. The contact angle of double ow angula contact ball beaings is 2. Thee ae also fou-point contact beaings that can suppot an axial load in both diections by themselves. These beaings howeve equie caution because poblems such as excessive tempeatue ise and weaing could occu depending on the load conditions. Table 1. Contact angle and symbol Contact angle Cylindical olle beaings Uses olles fo olling elements, and theefoe has a high load capacity. The olles ae guided by the ibs of the inne o oute ing. The inne and oute ings can be sepaated to facilitate assembly, and both can be fit with shaft o housing tightly. If thee is no ibs, eithe the inne o the oute ing can move feely in the axial diection. Cylindical olle beaings ae theefoe ideal to be used as so-called "fee side beaings" that absob shaft expansion. In the case whee thee is a ibs, the beaing can bea a slight axial load between the end of the olles and the ibs. Cylindical olle beaings include the HT type which modifies the shape of olle end face and ibs fo inceasing axial oad capacity. And the E type with a special intenal design fo enhancing adial load capacity. The E type is standadized fo small-diamete sizes. Table 1. shows the basic configuation fo cylindical olle beaings. In addition to these, thee ae cylindical olle beaings with multiple ows of olles and the SL type of full complement olle beaing without cage. Contact angle and contact angle symbol Contact angle Contact angle symbol 1 C A Note 1: Contact angle symbol has been abbeviated as "A". 1 B Table 1. Types of cylindical olle beaings Type and Symbol NU type N type NJ type NF type NUP type NH type NJ+HJ Table 1. Configuation of double ow angula contact ball beaings Type and symbol Open Shield ZZ Non-contact sealed LLM Contact sealed LLD Dawings NU type NJ type NUP type Configuation N type NF type NH type Table 1. Combinations of duplex angula contact ball beaings Type and symbol Back-to-back duplex DB Face-to-face duplex DF Tandem duplex DT Configuation A-9

12 Classification and Chaacteistics of Rolling Beaings Tapeed olle beaings Tapeed olle beaings ae designed so the inne/oute ing aceway and apex of the tapeed olles intesect at one point on the beaing centeline. By eceiving combined load fom inne and oute ing, the olles ae pushed against the inne ing ib and oll guided with ib. Induced foce is poduced in the axial diection when a adial load is applied, so must be handled by using a pai of beaings. The inne ing with olles and oute ing come apat, thus facilitating mounting with cleaance o peload. Assembled cleaance is howeve had to manage and equies special attention. Tapeed olle beaings ae capable of suppoting lage loads in both the axial and adial diections. NTN beaings with T-, ET-, T- and U attached to the name confom to ISO and JIS standads fo sub-unit dimensions (nominal contact angle, nominal small end diamete of oute ing) and ae intenationally intechangeable. NTN also has a line of case hadened steel beaings designed fo longe life (ETA-, ET-, etc.). NTN tapeed olle beaings also include beaings with two and fou ows of tapeed olles fo exta-heavy loads. Spheical olle beaings Equipped with an oute ing with a spheical aceway suface and an inne ing which holds two ows of baelshaped olling elements, NTN spheical olle beaings ae able to adjust cente alignment to handle inclination of the axle o shaft. Thee ae vaiety of beaing types that diffe accoding to intenal design. Spheical olle beaings include as type equipped with an inne ing with a tapeed boe. The beaing can easily be mounted on a shaft by means of an adapte o withdawal sleeve. The beaing is capable of suppoting heavy loads, and is theefoe often used in industial machiney. When heavy axial load is applied to the beaing, the load on olles of anothe ow is disappeaed, and can cause poblems. Attention must theefoe be paid to opeating conditions. Table 1.7 Types of spheical olle beaings Type Configuation Standad (B type) C type 21 type E type Thust beaings Sub-unit dimensions 2α E Thee ae many types of thust beaings that diffe accoding to shape of olling element and application. Allowable otational speed is geneally low and special attention must be paid to lubication. In addition to the ones given below, thee ae vaious types of thust beaings fo special applications. Fo details, see the catalog devoted to the concened type of beaing. Enominal small end diamete of oute ing αnominal contact angle Fig. 1. Tapeed olle beaings Table 1.8 Types of thust beaings Type Single diection thust ball beaing Needle olle thust beaing AXK type AS type aceway washe Configuation Cylindical olle thust beaing GS/WS type aceway washe Spheical olle thust beaing Cente alignment angle A-1

13 Classification and Chaacteistics of Rolling Beaings Needle olle beaings Needle olle beaings use needle olles as olling elements. The needle olles ae a maximum of mm in diamete and ae to 1 times as long as they ae in diamete. Because the beaings use needle olles as olling elements, the coss-section is thin, but they have a high load capacity fo thei size. Because of the lage numbe of olling elements, the beaings have high igidity and ae ideally suited to wobbling o pivoting motion. Thee is a pofusion of types of needle olle beaings, and just a few of the most epesentative types ae coveed hee. Fo details, see the catalog devoted to the concened type of beaing. Table 1.9 Main types of needle olle beaings Type Needle olle beaing with cage Beaing unit A unit compised of a ball beaing inseted into vaious types of housings. The housing can be bolted onto machiney and the inne ing can be easily mounted on the shaft with a set scew. This means the beaing unit can suppot otating equipment without special design to allow fo mounting. A vaiety of standadized housing shapes is available, including pillow and flange types. The oute diamete of the beaing is spheical just like the inne diamete of the housing, so it capable of aligning itself on the shaft. Fo lubication, gease is sealed inside the beaing, and paticle geneation is pevented by a double seal. Fo details, see the catalog devoted to the concened type of beaing. Ball Gease fitting Housing Spheical oute ing Solid type needle olle beaings Slinge Special ubbe seal Configuation Shell type needle olle beaings Setscew with ball Fig. 1. Oil-lubicated beaing unit Rolle followe Cam followe A-11

14 Beaing Selection 2. Beaing Selection Rolling element beaings ae available in a vaiety of types, configuations, and sizes. When selecting the coect beaing fo you application, it is impotant to conside seveal factos, and analyse in vaious means. A compaison of the pefomance chaacteistics fo each beaing type is shown in Table 2.1. As a geneal guideline, the basic pocedue fo selecting the most appopiate beaing is shown in the following flow chat. 2.1 Beaing selection flow chat Pocedue Confimation items Confim opeating conditions and opeating envionment Function and constuction of components to house beaings Beaing mounting location Beaing load (diection and magnitude) Rotational speed Vibation and shock load Beaing tempeatue (Ambient tempeatue / tempeatue ise) Opeating envionment (potential fo coosion, degee of contamination, extent of lubication) Select beaing type and configuation Dimensional limitations (efe to page inset A-) Beaing load (magnitude, diection, vibation; pesence of shock load) (efe to page inset A-21) Rotational speed (efe to page inset A-7) Beaing toleances (efe to page inset A-) Rigidity (efe to page inset A-7) Allowable misalignment of inne/oute ings (efe to page inset A-87) Fiction toque (efe to page inset A-71) Beaing aangement (fixed side, floating side) (efe to page inset A-1) Installation and disassembly equiements (efe to page inset A-88) Beaing availability and cost Select beaing dimensions Design life of components to house beaings (efe to page inset A-19) Dynamic/static equivalent load conditions (efe to page inset A-2) Safety facto (efe to page inset A-19) Allowable speed (efe to page inset A-7) Allowable axial load (efe to page inset A-19, 2) Allowable space (efe to page inset A-) Select beaing toleances Shaft unout toleances (efe to page inset A-) Rotational speed (efe to page inset A-7) Toque fluctuation Selection of beaing type and configuation (1) Dimensional limitations The allowable space fo beaings is geneally limited. In most cases, shaft diamete (o the beaing boe diamete) has been detemined accoding to the machine s othe design specifications. Theefoe, beaing s type and dimensions ae detemined accoding to beaing boe diametes. Fo this eason all dimension tables ae oganized accoding to standad boe diametes. Thee is a wide ange of standadized beaing types and dimensions: the ight one fo a paticula application can usually be found in these tables. (2) Beaing load The chaacteistics, magnitude, and diection of loads acting upon a beaing ae extemely vaiable. In geneal, the basic load atings shown in beaing dimension tables indicate thei load capacity. Howeve, in detemining the appopiate beaing type, consideation must also be given to whethe the acting load is a adial load only o combined adial and axial load, etc. When ball and olle beaings within the same dimension seies ae consideed, the olle beaings have a lage load capacity and ae also capable of withstanding geate vibation and shock loads. () Rotational speed The allowable speed of a beaing will diffe depending upon beaing type, size, toleances, cage type, load, lubicating conditions, and cooling conditions. The allowable speeds listed in the beaing tables fo gease and oil lubication ae fo nomal toleance NTN beaings. In geneal, deep goove ball beaings, angula contact ball beaings, and cylindical olle beaings ae most suitable fo high speed applications. () Beaing toleances The dimensional accuacy and opeating toleances of beaings ae egulated by ISO and JIS standads. Fo equipment equiing high toleance shaft unout o high speed opeation, beaings with Class toleance o highe ae ecommended. Deep goove ball beaings, angula contact ball beaings, and cylindical olle beaings ae ecommended fo high otational toleances. () Rigidity Elastic defomation occus along the contact sufaces of a beaing s olling elements and aceway sufaces unde loading. With cetain types of equipment it is necessay to educe this defomation as much as A-12

15 Beaing Selection Select beaing s intenal cleaance Select cage type and mateial Select lubicant, lubication method, sealing method Select any special beaing specifications Confim handling pocedues Mateial and shape of shaft and housing (efe to page inset A-8) Fit (efe to page inset A-9) Tempeatue diffeential between inne/oute ings (efe to page inset A-9) Allowable misalignment of inne/oute ings (efe to page inset A-87) Load (magnitude, natue) (efe to page inset A-21) Amount of peload (efe to page inset A-) Rotational speed (efe to page inset A-7) Rotational speed (efe to page inset A-7) Noise level Vibation and shock load Momentay load Lubication type and method (efe to page inset A-72) Opeating tempeatue (efe to page inset A-72) Rotational speed (efe to page inset A-7) Lubication type and method (efe to page inset A-72) Sealing method (efe to page inset A-8) Maintenance and inspection (efe to page inset A-9) Opeating envionment (high/low tempeatue, vacuum, phamaceutical, etc.) Requiement fo high eliability Installation-elated dimensions (efe to page inset A-8) Installation and disassembly pocedues (efe to page inset A-88) possible. Rolle beaings exhibit less elastic defomation than ball beaings. Futhemoe, in some cases, beaings ae given a load in advance (peloaded) to incease thei igidity. This pocedue is commonly applied to deep goove ball beaings, angula contact ball beaings, and tapeed olle beaings. () Misalignment of inne and oute ings Shaft flexue, vaiations in shaft o housing accuacy, and fitting eos. esult in a cetain degee of misalignment between the beaing s inne and oute ings. In cases whee the degee of misalignment is elatively lage, self-aligning ball beaings, spheical olle beaings, o beaing units with self-aligning popeties ae the most appopiate choices. (Refe to Fig. 2.1) (7) Noise and toque levels Rolling beaings ae manufactued and pocessed accoding to high pecision standads, and theefoe geneally poduce only slight amounts of noise and toque. Fo applications equiing paticulaly low-noise o low-toque opeation, deep goove ball beaings and cylindical olle beaings ae most appopiate. (8) Installation and disassembly Some applications equie fequent disassembly and eassembly to enable peiodic inspections and epais. Fo such applications, beaings with sepaable inne/oute ings, such as cylindical olle beaings, needle olle beaings, and tapeed olle beaings ae most appopiate. Incopoation of adapte sleeves simplifies the installation and disassembly of selfaligning ball beaings and spheical olle beaings with tapeed boes. Allowable misalignment angle Self-aligning ball beaing Allowable misalignment angle Spheical olle beaing Fig. 2.1 A-1

16 Beaing Selection 2.2 Type and chaacteistics Table 2.1 shows types and chaacteistics of olling beaings. Table 2.1 Type of olling beaings and pefomance compaison Beaing types Deep goove ball beaings Angula contact ball beaings Double ow angula contact ball beaings Duplex angula contact ball beaings Selfaligning ball beaings Cylindical olle beaings Singleflange cylindical olle beaings Doubleflange cylindical olle beaings Double ow cylindical olle beaings Needle olle beaings Chaacteistics Load Caying Capacity Radial load Axial load 1 High speed High otating accuacy 1 Low noise/vibation 1 Low fiction toque 1 High igidity 1 Vibation/shock esistance 1 Allowable misalignment fo inne/oute ings Stationay in axial diection 2 Moveable in axial diection Sepaable inne/oute ings 1 Inne ing tapeed boe Remaks Refeence page Fo DB and DF aangement Fo DB aangement Fo duplex NU, N NJ, NF NUP, NP, NH NNU, NN aangement type type type type B- B- B- B- B- B-77 B-77 B-77 B-12 NA type Tapeed olle beaings Double-ow, -ow tapeed olle beaings Spheical olle beaings Thust ball beaings Cylindical olle thust beaings Spheical olle thust beaings Refeence page Beaing types Chaacteistics Load Caying Capacity Radial load Axial load A-7 1 High speed A- High otating accuacy 1 Low noise/vibation 1 A-71 Low fiction toque 1 Fo duplex aangement B-119 B-119 B-219 B-2 Including needle olle thust beaing B-2 A-8 A-21 A-8 A-1 A-1 A-8 High igidity 1 Vibation/shock esistance 1 Allowable misalignment fo inne/oute ings Stationay in axial diection 2 Moveable in axial diection Sepaable inne/oute ings Inne ing tapeed boe Remaks Refeence page 1 1 The numbe of stas indicates the degee to which that beaing type displays that paticula chaacteistic. Not applicable to that beaing type. 2 Indicates dual diection. Indicates single diection axial movement only. indicates movement in the axial diection is possible fo the aceway suface; indicates movement in the axial diection is possible fo the fitting suface of the oute ing o inne ing. Indicates both inne ing and oute ing ae detachable. Indicates inne ing with tapeed boe is possible. A-1

17 Beaing Selection 2. Selection of beaing aangement Shafts o axles ae geneally suppoted by a pai of beaings in the axial and adial diections. The beaing which pevents axial movement of the shaft elative to the housing is called the "fixed side beaing" and the beaing which allows axial movement elatively is called the "floating-side beaing". This allows fo expansion and contaction of the shaft due to tempeatue vaiation and enables eo in beaing mounting cleaance to be absobed. The fixed side beaing is able to suppot adial and axial loads. A beaing which can fix axial movement in both diections should theefoe be selected. A floatingside beaing that allows movement in the axial diection while suppoting a adial load is desiable. Movement in the axial diection occus on the aceway suface fo beaings with sepaable inne and oute ings such as cylindical olle beaings, and occus on the fitting suface fo those which ae not sepaable, such as deep goove ball beaings. In applications with shot distances between beaings, shaft expansion and contaction due to tempeatue fluctuations is slight, theefoe the same type of beaing may be used fo both the fixed-side and floating-side beaing. In such cases it is common to use a set of matching beaings, such as angula contact ball beaings, to guide and suppot the shaft in one axial diection only. Table 2.2 (1) shows typical beaing aangements whee the beaing type diffes on the fixed side and floating side. Table 2.2 (2) shows some common beaing aangements whee no distinction is made between the fixed side and floating side. Vetical shaft beaing aangements ae shown in Table 2.2 (). Table 2.2 (1) Beaing aangement (distinction between fixed and floating-side) Fixed Aangement Floating Comment Application (Refeence) 1. Geneal aangement fo small machiney. 2. Fo adial loads, but will also accept axial loads. Small pumps, auto-mobile tansmissions, etc. 1. Suitable when mounting eo and shaft deflection ae minimal o used fo high otational speed application. 2. Even with expansion and contaction of shaft, floating side moves smoothly. Medium-sized electic motos, ventilatos, etc. 1. Radial loading and dual diection of axial loading possible. 2. In place of duplex angula contact ball beaings, double-ow angula contact ball beaings ae also used. Wom eduction gea 1. Heavy loading capable. 2. Shafting igidity inceased by peloading the two back-to-back fixed beaings.. Requies high pecision shafts and housings, and minimal fitting eos. Reduction geas fo geneal industial machiney 1. Allows fo shaft deflection and fitting eos. 2. By using an adapto on long shafts without scews o shouldes, beaing mounting and dismounting can be facilitated.. Self-aligning ball beaings ae used fo positioning in the axial diection, and not suitable fo applications equiing suppot of axial load. Geneal industial machiney 1. Widely used in geneal industial machiney with heavy and shock load demands. 2. Allows fo shaft deflection and fitting eos.. Accepts adial loads as well as dual diection of axial loads. Reduction geas fo geneal industial machiney 1. Accepts adial loads as well as dual diection axial loads. 2. Suitable when both inne and oute ing equie tight fit. Reduction geas fo geneal industial machiney 1. Capable of handling lage adial and axial loads at high otational speeds. 2. Maintains cleaance between the beaing s oute diamete and housing inne diamete to pevent deep goove ball beaings fom eceiving adial loads. Tansmissions fo diesel locomotives A-1

18 Beaing Selection Table 2.2 (2) Beaing aangement (no distinction between fixed and floating-side) Aangement Comment Application (Refeence) 1. Geneal aangement fo use in small machines. 2. Peload is sometimes applied by placing a sping on the oute ing side suface o inseting a shim. (can be floating-side beaings.) Small electic motos, small eduction geas, etc. 1. Back to back aangement is pefeable to face to face aangement when moment load applied. 2. Able to suppot axial and adial loads; suitable fo high-speed otation.. Rigidity of shaft can be enhanced by poviding peload. Machine tool spindles, etc. 1. Capable of suppoting exta heavy loads and impact loads. 2. Suitable if inne and oute ing tight fit is equied.. Cae must be taken that axial cleaance does not become too small duing opeation. Constuction equipment, mining equipment sheaves, agitatos, etc. Back to back 1. Withstands heavy and shock loads. Wide ange application. 2. Shaft igidity can be enhanced by poviding peload, but make sue peload is not excessive.. Back-to-back aangement fo moment loads, and face-to-face aangement to alleviate fitting eos.. With face-to-face aangement, inne ing tight fit is facilitated. Reduction geas, font and ea axle of automobiles, etc. Face to face Table 2.2 () Beaing aangement (Vetical shaft) Aangement Comment Application (Refeence) 1. When fixing beaing is a duplex angula contact ball beaing, floating beaing should be a cylindical olle beaing. Vetically mounted electic motos, etc. 1. Most suitable aangement fo vey heavy axial loads. 2. Shaft deflection and mounting eo can be absobed by matching the cente of the spheical suface with the cente of spheical olle thust beaings. Cane cente shafts, etc. A-1

19 Load Rating and Life. Load Rating and Life.1 Beaing life Even in beaings opeating unde nomal conditions, the sufaces of the aceway and olling elements ae constantly being subjected to epeated compessive stesses which causes flaking of these sufaces to occu. This flaking is due to mateial fatigue and will eventually cause the beaings to fail. The effective life of a beaing is usually defined in tems of the total numbe of evolutions a beaing can undego befoe flaking of eithe the aceway suface o the olling element sufaces occus. Othe causes of beaing failue ae often attibuted to poblems such as seizing, abasions, cacking, chipping, scuffing, ust, etc. Howeve, these so called "causes" of beaing failue ae usually themselves caused by impope installation, insufficient o impope lubication, faulty sealing o inaccuate beaing selection. Since the above mentioned "causes" of beaing failue can be avoided by taking the pope pecautions, and ae not simply caused by mateial fatigue, they ae consideed sepaately fom the flaking aspect..2 Basic ating life and basic dynamic load ating A goup of seemingly identical beaings when subjected to identical load and opeating conditions will exhibit a wide divesity in thei duability. This "life" dispaity can be accounted fo by the diffeence in the fatigue of the beaing mateial itself. This dispaity is consideed statistically when calculating beaing life, and the basic ating life is defined as follows. The basic ating life is based on a 9% statistical model which is expessed as the total numbe of evolutions 9% of the beaings in an identical goup of beaings subjected to identical opeating conditions will attain o supass befoe flaking due to mateial fatigue occus. Fo beaings opeating at fixed constant speeds, the basic ating life (9% eliability) is expessed in the total numbe of hous of opeation. Basic dynamic load ating expesses a olling beaing's capacity to suppot a dynamic load. The basic dynamic load ating is the load unde which the basic ating life of the beaing is 1 million evolutions. This is expessed as pue adial load fo adial beaings and pue axial load fo thust beaings. These ae efeed to as "basic dynamic load ating (C)" and "basic dynamic axial load ating (Ca)." The basic dynamic load atings given in the beaing tables of this catalog ae fo beaings constucted of NTN standad beaing mateials, using standad manufactuing techniques. The elationship between the basic ating life, the basic dynamic load ating and the beaing load is given in fomula. Fo ball beaings: L 1 C.1 P Fo olle beaings: L 1 C 1/.2 P whee, L1 : Basic ating life 1 evolutions C : Basic dynamic load ating, N {kgf} (C: adial beaings, Ca: thust beaings) P : Equivalent dynamic load, N {kgf} (P: adial beaings, Pa: thust beaings) n : Rotational speed, min -1 The elationship between Rotational speed n and speed facto fn as well as the elation between the basic ating life L1h and the life facto fn is shown in Table.1 and Fig..1. Table.1 Coelation of beaing basic ating life, life facto, and speed facto Classification Ball beaing Rolle beaing Basic ating life L1h h Life facto fh Speed facto fn n min -1,,, 2, 1, 1, 8,,,, 2, 1, 1, C ( ) n fn h 8,,,, 2, 1,.2 1, fn P L1h 8,,,, 2, 1, 1, C P. ( n ) Ball beaings = fh n 1/.,,., 2, 1,. 1, 8,, fh n fn L1h min -1,, 2, 1, 1, C ( ) h P Rolle beaings 8,,,, 2, 1, 1, 8,,,, 2, 1, 1, / fn.8 C P fh.7 = fh. ( n ) /1 1/ Fig..1 Beaing life ating scale A-17

20 Load Rating and Life When seveal beaings ae incopoated in machines o equipment as complete units, all the beaings in the unit ae consideed as a whole when computing beaing life (see fomula.). 1 L e. L 1 e L 2 e L n e whee, L : Total basic ating life of entie unit, h L1 L2 Ln: Basic ating life of individual beaings, 1, 2, n, h e = 1/9...Fo ball beaings e = 9/8...Fo olle beaings When the load conditions vay at egula intevals, the life can be given by fomula (.). Lm 1 2 j -1. L1 L2 L j whee, L m : Total life of beaing j : Fequency of individual load conditions ( j = 1) L j : Life unde individual conditions If equivalent load P and otational speed n ae opeating conditions of the beaing, basic ated dynamic load C that satisfies equied life of the beaing is detemined using Table.1 and fomula (.). Beaings that satisfy the equied C can be selected fom the beaing dimensions table povided in the catalog. fh C P. fn. Adjusted ating life The basic beaing ating life (9% eliability facto) can be calculated though the fomulas mentioned ealie in Section.2. Howeve, in some applications a beaing life facto of ove 9% eliability may be equied. To meet these equiements, beaing life can be lengthened by the use of specially impoved beaing mateials o manufactuing pocess. Beaing life is also sometimes affected by opeating conditions such as lubication, tempeatue and otational speed. Basic ating life adjusted to compensate fo this is called "adjusted ating life," and is detemined using fomula (.). Lna a1a2al1. whee, Lna : Adjusted ating life in millions of evolutions (1 ) a1 : Reliability facto a2 : Beaing chaacteistics facto a : Opeating conditions facto..1 Reliability facto a1 The value of eliability facto a1 is povided in Table.2 fo eliability of 9% o geate...2 Beaing chaacteistics facto a2 Beaing chaacteistics concening life vay accoding to beaing mateial, quality of mateial and if using special manufactuing pocess. In this case, life is adjusted using beaing chaacteistics facto a2. The basic dynamic load atings listed in the catalog ae based on NTN's standad mateial and pocess, theefoe, the adjustment facto a2 1. a2 1 may be used fo specially enhanced mateials and manufactuing methods.if this applies, consult with NTN Engineeing. Dimensions change significantly if beaings made of high cabon chome beaing steel with conventional heat teatment ae used at tempeatues in excess of 12 C fo an extended peiod of time. NTN Engineeing theefoe offes a beaing fo high-tempeatue applications specially teated to stabilize dimensions at the maximum opeating tempeatue (TS teatment). The teatment howeve makes the beaing softe and affects life of the beaing. Life is adjusted by multiplying by the values given in Table.. Table.2 Reliability facto a1 Reliability % Ln Reliability facto a1 Symbol L1 L L L L2 L1 Max. opeating tempeatue (C ) Table. Teatment fo stabilizing dimensions TS TS 2 2 Beaing chaacteistics facto a2 TS Opeating conditions facto a Opeating conditions facto a is used to compensate fo when lubication condition wosens due to ise in tempeatue o otational speed, lubicant deteioates, o becomes contaminated with foeign matte. Geneally speaking, when lubicating conditions ae satisfactoy, the a facto has a value of one; and when lubicating conditions ae exceptionally favoable, and all othe opeating conditions ae nomal, a can have a value geate than one. a is howeve less than 1 in the following cases: A-18

21 Load Rating and Life Dynamic viscosity of lubicating oil is too low fo beaing opeating tempeatue (1 mm 2 /s o less fo ball beaings, 2 mm 2 /s fo olle beaings) Rotational speed is paticulaly low (If sum of otational speed n min -1 and olling element pitch diamete Dpw mm is Dpwn 1,) Beaing opeating tempeatue is too high If beaing opeating tempeatue is too high, the aceway becomes softened, theeby shotening life. Life is adjusted by multiplying by the values given in Fig..2 as the opeating condition facto accoding to opeating tempeatue. This howeve does not apply to beaings that have been teated to stabilize dimensions. Lubicant contaminated with foeign matte o moistue If using special opeating condition, consult with NTN Engineeing. Even if a2 1 is used fo specially beaings made of enhanced mateials o poduced by special manufactuing methods, a2a 1 is used if lubicating conditions ae not favoable. Opeating conditions facto a Opeating tempeatue C Fig..2 Opeating conditions facto accoding to opeating tempeatue When a supe heavy load is applied, hamful plastic distotion could be poduced on the contact sufaces of the olling elements and aceway. The fomulae fo detemining basic ating life (.1,.2, and.) do not apply if P exceeds eithe Co (Basic static load ating) o. C fo adial beaings, o if Pa exceeds. Ca fo thust beaings.. Machine applications and equisite life When selecting a beaing, it is essential that the equisite life of the beaing be established in elation to the opeating conditions. The equisite life of the beaing is usually detemined by the type of machine in which the beaing will be used, and duation of sevice and opeational eliability equiements. A geneal guide to these equisite life citeia is shown in Table.. When detemining beaing size, the fatigue life of the beaing is an impotant facto; howeve, besides beaing life, the stength and igidity of the shaft and housing must also be taken into consideation.. Basic static load ating When stationay olling beaings ae subjected to static loads, they suffe fom patial pemanent defomation of the contact sufaces at the contact point between the olling elements and the aceway. The amount of defomity inceases as the load inceases, and if this incease in load exceeds cetain limits, the subsequent smooth opeation of the beaings is impaied. It has been found though expeience that a pemanent defomity of.1 times the diamete of the olling element, occuing at the most heavily stessed contact point between the aceway and the olling elements, can be toleated without any impaiment in unning efficiency. Table. Machine application and equisite life (efeence) Sevice classification Machines used fo shot peiods o used only occasionally Shot peiod o intemittent use, but with high eliability equiements Machines not in constant use, but used fo long peiods Machine application and equisite life (efeence) L1h Household appliances Electic hand tools Medical appliances Measuing instuments Automobiles Two-wheeled vehicles Fam machiney Office equipment Home ai- conditioning moto Constuction equipment Elevatos Canes Small motos Buses/tucks Geneal gea dives Woodwoking machines Cane (sheaves) Machine spindles Industial motos Cushes Vibating sceens Main gea dives Rubbe/plastic Calende olls Pinting machines 1 h Machines in constant use ove 8 hous a day Rolling mills Escalatos Conveyos Centifuges Railway vehicle axles Ai conditiones Lage motos Compesso pumps Locomotive axles Taction motos Mine hoists Pessed flywheels Papemaking machines Populsion equipment fo maine vessels Wate supply equipment Mine dain pumps/ventilatos Powe geneating equipment 2 hou continuous opeation, non-inteuptable A-19

22 Load Rating and Life The basic static load ating efes to a fixed static load limit at which a specified amount of pemanent defomation occus. It applies to pue adial loads fo adial beaings and to pue axial loads fo thust beaings. The maximum applied load values fo contact stess occuing at the olling element and aceway contact points ae given below. Fo ball beaings,2 MPa {28kgf/mm 2 } Fo self-aligning ball beaings, MPa {9kgf/mm 2 } Fo olle beaings, MPa {8kgf/mm 2 } This is geneally detemined by taking the safety facto So given in Table. and fomula (.7) into account. So CoPo.7 whee, So : Safety facto Co : Basic static load ating, N {kgf} (adial beaings: Co, thust beaings: Coa) Po : Static equivalent load, N {kgf} (adial: Po, thust: Coa) Refeed to as "basic static adial load ating" fo adial beaings and "basic static axial load ating" fo thust beaings, basic static load ating is expessed as Co o Coa espectively and is povided in the beaing dimensions table. Table. Minimum safety facto values S Opeating conditions High otational accuacy demand Nomal otating accuacy demand (Univesal application) Ball beaings 2 1 Rolle beaings 1.. Allowable static equivalent load Geneally the static equivalent load which can be pemitted (See page A-2) is limited by the basic static ating load as stated in Section.. Howeve, depending on equiements egading fiction and smooth opeation, these limits may be geate o lesse than the basic static ating load. Slight otational accuacy deteioation pemitted (Low speed, heavy loading, etc.) Note 1: Fo spheical thust olle beaings, min. S value=. 2: Fo shell needle olle beaings, min. S value=. : When vibation and/o shock loads ae pesent, a load facto based on the shock load needs to be included in the P max value. : If a lage axial load is applied to deep goove ball beaings o angula ball beaings, the contact oval may exceed the aceway suface. Fo moe infomation, please contact NTN Engineeing.. 1 A-2

23 Beaing Load Calculation. Beaing Load Calculation To compute beaing loads, the foces which act on the shaft being suppoted by the beaing must be detemined. Loads which act on the shaft and its elated pats include dead load of the otato, load poduced when the machine pefoms wok, and load poduced by tansmission of dynamic foce. These can theoetically be mathematically calculated, but calculation is difficult in many cases. A method of calculating loads that act upon shafts that convey dynamic foce, which is the pimay application of beaings, is povided heein..1 Load acting on shafts.1.1 Load facto Thee ae many instances whee the actual opeational shaft load is much geate than the theoetically calculated load, due to machine vibation and/o shock. This actual shaft load can be found by using fomula (.1). K fwkc.1 whee, K Actual shaft load Nkgf fw Load facto (Table.1) KcTheoetically calculated value Nkgf Ks KttanSpu gea.a K t tan Helical gea.b cos K Kt 2 Ks 2. Ka KttanHelical gea. whee, KtTangential gea load (tangential foce), N {kgf} KsRadial gea load (sepaating foce), N {kgf} KRight angle shaft load (esultant foce of tangential foce and sepaating foce), N {kgf} KaPaallel load on shaft, N {kgf} H Tansmission foce, kw n Rotational speed, min -1 DpGea pitch cicle diamete, mm Gea pessue angle, deg Gea helix angle, deg Because the actual gea load also contains vibations and shock loads as well, the theoetical load obtained by the above fomula should also be adjusted by the gea facto fz as shown in Table.2. Table.1 Load facto fw Amount of shock Vey little o no shock fw Application Electic machines, machine tools, measuing instuments. Ks Light shock Heavy shock Railway vehicles, automobiles, olling mills, metal woking machines, pape making machines, pinting machines, aicaft, textile machines, electical units, office machines. Cushes, agicultual equipment, constuction equipment, canes. Kt Fig..1 Spu gea loads.1.2 Gea load The loads opeating on geas can be divided into thee main types accoding to the diection in which the load is applied; i.e. tangential (Kt), adial (Ks), and axial (Ka). The magnitude and diection of these loads diffe accoding to the types of geas involved. The load calculation methods given heein ae fo two geneal-use gea and shaft aangements: paallel shaft geas, and coss shaft geas. Fig..2 Kt Ks Ka Kt Helical gea loads (1)Loads acting on paallel shaft geas The foces acting on spu geas and helical geas ae depicted in Figs..1,.2, and.. The load magnitude can be found by using o fomulas (.2), though (.). K t H D N pn H D kgf pn K Fig.. Ks Dp Radial esultant foces A-21