Rolling bearings in industrial gearboxes

1 Rolling bearings in industrial gearboxes Copyright SKF 1997 The contents of this publication are thecopyright of the publisher and may notbe reproduced (even extracts) unlesspermission is granted. Every care hasbeen taken to ensure the accuracy ofthe information contained in this publi-cation but no liability can be acceptedfor any loss or damage whether direct,indirect or consequential arising out ofthe use of the information EPrinted in Denmark on environmentallyfriendly, chlorine-free paper (MultiartSilk) by Scanprint as1 industrial gearboxes overview2 Bearing types for industrial gearboxes3 Design of bearing arrangements4 Dimensioning the bearing arrangement5 Lubrication and maintenance6 Recommended fits7 Mounting and dismounting bearings8 Application examples12345678 Rolling bearings in industrial gearboxesRolling bearings inindustrial gearboxesHandbook for the gearbox designerForewordThis Handbook is intended to provide the gearbox designerwith the knowledge required to select bearings for gearboxesand to correctly design gearbox bearing arrangements.

2 Recom-mendations are given based on experience gained by SKFduring decades of cooperation with gearbox manufacturers theworld information regarding the selection, calculation,mounting and maintenance of ball and roller bearings is givenin the SKF General Catalogue. The questions arising from theuse of Rolling bearings in industrial gearboxes are dealt withhere. Data from the General Catalogue are only repeated herewhen it has been thought necessary for the sake of application examples described comprise proven gearbox designs from major manufacturers which are worthy of thanks are extended to the companies concernedfor the provision of the detailed information about their prod-ucts and the permission to bearings in industrial gearboxes41 industrial gearboxes overview.

3 9 Types of gearbox .. 9 Geared 10 Demands made on gearboxes .. 14 Selecting the gears .. 14 Designing the casing .. 152 Bearing types for industrial gearboxes .. 17 Deep groove ball bearings .. 18 Angular contact ball bearings .. 20 Cylindrical roller bearings .. 22 CARB roller bearings .. 24 Spherical roller bearings .. 26 Taper roller bearings .. 28 Spherical roller thrust bearings .. 303 Design of bearing 33 Shafts and gear wheels in spur gearboxes .. 33 Shafts in bevel gearboxes .. 44 Shafts in worm 50 Shafts and gear wheels for planetary 56 Made by SKF stands for excellence. It symbolises our consistent endeavour to achieve total quality in everything we do. For those who use our products, Made by SKF implies three main thanks to modern, efficient products, basedon our worldwide application know-how, optimised materials, forward-looking designs and the most advanced production effectiveness resulting from the favourable ratiobetween our product quality plus service facilities, andthe purchase price of the lead which you can achieve by taking advantage of our products and services.

4 Increased operating time and reduced down-time, as well as improved output and product quality are the key to a successful of bearing arrangement .. 65 Bearing loads .. 65 Determination of external forces .. 66 Calculation of bearing loads .. 74 Dimensioning the bearing arrangement .. 765 Lubrication and 91 Grease 92 Oil lubrication .. 95 Maintenance .. 986 Recommended fits ..1037 Mounting and dismounting bearings .. 109 Adjustment of angular contact 1098 Application examples .. 115 Rolling bearings in industrial gearboxes6 SKF is an international industrial Groupoperating in some 130 countries and isworld leader in company was founded in 1907following the invention of the self-align-ing ball bearing by Sven Wingquist and,after only a few years, SKF began toexpand all over the , SKF has some 43 000 em-ployees and more than 80 manufactur-ing facilities spread throughout theworld.

5 An international sales network includes a large number of sales com-panies and some 20 000 distributorsand retailers. Worldwide availability ofSKF products is supported by a com-prehensive technical advisory key to success has been a con-sistent emphasis on maintaining thehighest quality of its products and services. Continuous investment inresearch and development has alsoplayed a vital role, resulting in manyexamples of epoch-making business of the Group consistsof bearings , seals, special steel and acomprehensive range of other high-tech industrial components. The ex-perience gained in these various fieldsprovides SKF with the essential know-ledge and expertise required in orderto provide the customers with the mostadvanced engineering products andefficient SKF Group a worldwide corporationSKF manufacturesball bearings , roller bearings and plainbearings.

6 The smal-lest are just a fewmillimetres (a frac-tion of an inch) indiameter, the largestseveral metres. Inorder to protect thebearings effectivelyagainst the ingressof contaminationand the escape oflubricant, SKF alsomanufactures oiland bearing 's subsidiariesCR and RFT among the world's largest pro-ducers of SKF house colours are blue and red,but the thinking is green. The latest exampleis the new factory in Malaysia, where thebearing component cleaning process con-forms to the strictest ecological of trichloroethylene, a water-basedcleaning fluid is used in a closed cleaning fluid is recycled in the factory'sown treatment has developed the Channel concept infactories all over the world. This drasticallyreduces the lead time from raw material toend product as well as work in progress and finished goods in stock.

7 The conceptenables faster and smoother informationflow, eliminates bottlenecks and bypassesunnecessary steps in production. TheChannel team members have the know-ledge and commitment needed to share theresponsibility for fulfilling objectives in areassuch as quality, delivery time, productionflow SKF Engineering & Research Centre is situated just outside Utrecht in TheNetherlands. In an area of 17 000 squaremetres (185 000 ) some 150 scientists,engineers and support staff are engaged inthe further improvement of bearing perform-ance. They are developing technologiesaimed at achieving better materials, betterdesigns, better lubricants and better seals together leading to an even better unders- tanding of the operation of a bearing in itsapplication.

8 This is also where the SKF New Life Theory was evolved, enabling thedesign of bearings which are even morecompact and offer even longer gearboxes overviewTypes of gearbox .. 9 Geared transmission .. 10 Demands on gearboxes .. 14 Selecting the gears .. 14 Designing the casing .. 1519 industrial gearboxes overviewGearboxes are devices for the transmission ortranslation of movement. In industry gearboxesare used to transform the speeds and torquesproduced by the prime mover in order thatthey are appropriate to the machine which is tobe driven. The speeds and torques required bythe machine are dictated by its use. Primemovers can generally only meet these require-ments when combined with of gearboxGearboxes are characterised by havingat least three members: the power in-put, power take-off and the casing.

9 Thecasing transmits the support momentto the contrast, a coupling has only twomembers: the power input and power1 industrial gearboxes overviewTypes of gearboxP1M1 PVP2M2n2n1P2P1M2 PvM1n1n2take-off. The coupling housing has nopart in the flow of symbols used for powertransmission by gearboxes and coup-lings are shown in figsand .21 Fig1 Fig2 GearTorqueM1<M2>Rotational speedn1 n2>PowerP1=P2+ PvCouplingTorqueM1=M2 Rotational speedn1 n2 PowerP1=P2+ Pv(with slip)Geared transmissionsGeared transmissions are the mostcommonly used. They transmit powerwithout slip, have high operational re-liability and long life, require little main-tenance and are characterised by theability to accept overloading, small sizeand high gearsThe spur gear is the most well-knownand commonly used design of gearedtransmission.

10 The dimensioning andmanufacture of the gear wheels arethe easiest to control. Their kinematicbehaviour also forms the basis of plan-etary gears. Spur gears are in rollingcontact and, irrespective of tooth type,have parallel gearboxes overviewGeared transmissions10 The main types ofpower transmis-sion equipmentare shown in addition, thereare many com-binations, for ex-ample bevel/spurgears, spur gearswith belt drive input,or variable tractiondrives combinedwith a of gearboxFixed ratio transmissions, shift transmissionGeared transmissions Spur gears Planetary gears Bevel gears Worm gears Hypoid gears Helical gearsEccentric drives Cyclo drives Harmonic drivesTraction drives Belt drives Chain drivesInfinitely variable transmissionsMechanical transmissions Belt drives Roller drives Ratchet gearsHydraulic transmissions Hydrostatic transmissions Hydrodyanmic transmissions Gear wheels with straight cut teeth( figa) are simple in designand can be accurately axial forces generated by in-accuracies and deformations (twisting) are negligible.