Linear and Motion Solutio Solutions Needle Bearings

NEEDLE BEARINGS General Catalogue

Principal units Equivalent title hour time title millimeter metre per second per second speed (rotational) newton metre kinematic viscosity square metre per second square millimetres per second degrees centigrade Comments The information given in this catalogue can be subject to modication and deletions. Information and advice contained herein may be insufcient given the conditions of individual applications. Consult our Technical Department. Nadella does not accept any responsibility for errors or omissions. Certain products mentioned in this catalogue involve proprietary rights of manufacture,...

FC FCS, FCL-K, FC-K FCB FCBL-K, FCBN-K NK-NKS NKJ-NKJS AXNB - ARNB AXNBT - ARNBT

TECHNICAL FEATURES RADIAL NEEDLE ROLLER AND CAGE ASSEMBLIES 37 DRAWN CUP ROLLER CLUTCHES 77 BEARINGS WITH CAGE - GUIDED NEEDLES 91 FULL COMPLEMENT NEEDLE BEARINGS 103 NEEDLE THRUST BEARINGS ROLLER THRUST BEARINGS PRECISION COMBINED BEARINGS, WITH ADJUSTABLE AXIAL PRELOAD 177 SUMMARY TABLE - INNER RINGS 205

TECHNICAL FEATURES TECHNICAL FEATURES

Technical features 1. GENERAL 2. BEARING TYPE SELECTION 3. CALCULATIONS FOR RADIAL AND THRUST BEARINGS 3.1. BEARING LIFETIME 3.1.1. Dynamic capacity C 3.1.2. Nominal life L10 3.1.3. Modied life Lna 3.1.4. Variable loads and speeds 3.1.5. Oscillating motion 3.1.6. Application criteria MINIMUM LOAD STATIC CAPACITY Co AND LIMIT LOAD Po LIMITING SPEED SHAFT FOR BEARINGS WITHOUT INNER RING 4.1.1. Heat treatment of raceways 4.1.2. Surface nish 4.1.3. Tolerances and form deviations 4.1.4. End chamfer 4.1.5. Surface in contact with seals SHAFT FOR BEARINGS WITH INNER RING 4.2.1. Surface nish of the shaft...

Technical features LUBRICANT FEATURES 5.1.1. Base oil 5.1.2. Additives GREASE LUBRICATION 5.2.1. Main types of grease 5.2.2. Consistency 5.2.3. Special grease 5.2.4. Compatibility of greases 5.2.5. Application 5.2.6. Quantity of grease 5.2.7. Re-lubrication OIL LUBRICATION 5.3.1. Viscosity 5.3.2. Application of the lubricant

Technical features 1. GENERAL The choice of a bearing depends on many factors that need to be examined in order to obtain the most successful results at the lowest cost. In most cases the selection should be made when the overall design of the machine has been decided. Dimensional limits are then known, also the speeds and loads. At this stage the choice can be made from the many types of bearings offered from the standard ranges. The notes given in this section will generally permit one to select the most suitable bearing for each application. As for all other types of bearing, the results obtained...

Technical features 3. CALCULATIONS FOR RADIAL AND THRUST BEARINGS The details following enable one to evaluate lifetime of radial bearings and thrust bearings and also combined bearings which comprise a radial and a thrust component. These are calculated separately without transforming the axial load into an equivalent radial load. The calculation for a radial or thrust bearing must take account of the following principal factors: Other features such as lubrication, sealing and alignment must be considered in order to avoid introducing unfavourable factors. The formulas for lifetime calculations...

Technical features 3.1.3. Modied life Lna In conditions different from the mentioned above, a modied life Lna can be determined (in millions of revolutions) following the general formula: in which a1 and aISO are correction factors linked respectively to reliability, contamination and lubrication. Reliability correction factor a1 A reliability factor in excess of 90% may be required in certain industries elds, such as aviation, for reasons of security and to reduce the risk of a very costly immobilisation. The table below indicates the values of the correction factor a1 as a function of reliability:...

Technical features 3.1.5. Oscillating motion In order to calculate the life during oscillating motion it is necessary to determine an equivalent speed n in revolutions per minute from the formula: nosc: number of oscillations "Forward and Return" per minute α: amplitude of oscillation "Forward" in degrees. However, this formula risks being in error and giving inaccurate lives for oscillations at small amplitudes. It is therefore recommended not to apply it for angles of oscillation below 15°. When the angle of oscillation is very small fretting corrosion is likely to be produced and a suitable...

Technical features The resistance torque M of a bearing supporting a load P is given by the following relationships: (with Fw is the diameter of the inner raceway of the bearing) • Thrust bearing: M = f-P- — with dm = Eb+ Ea (Eb and Ea being the internal and external raceway diameters given in table of dimensions). The coefficient of friction f depends on a number of factors, amongst which are: • applied load • surface finish and alignment of raceways. The mean values shown below are for oil lubrication f = 0,002 T- 0,003 for caged needle bearings f = 0,003 T- 0,004 for full complement bearings...

Technical features 4. MOUNTING 4.1. SHAFT FOR BEARINGS WITHOUT INNER RING 4.1.1. Heat treatment of raceways The minimum hardness of 58-64 HRC required to apply the calculations without reducing the basic capacities may be obtained with a through-hardened bearing steel or with a case-hardened and tempered steel. In the latter case, the hardened case must be homogeneous and regular over the entire surface of the raceway: the case depth is the thickness between the surface and the core having a hardness value of Vickers HV1 of 550 (see Standard NF A 04 202). The minimum effective case depth of hardening...

Technical features 4.3. HOUSING FOR BEARINGS WITH OUTER RING 4.3.1. Surface nish of the shaft Maximum roughness suggested: Ra = 1,6 μm 4.3.2. Tolerances and form deviations The suggested tolerances for the housing is indicated in the appropriate chapters specic for every product. The suggested tolerance for deviation of form is - Variation of mean housing diameter within the length in contact with needle: 0.013 mm - Deviation from circular form: one-half of the diameter tolerance of the housing 4.3.3. End chamfer For the most effective assembly provide a chamfer to the ends of the shaft on which...