Precision Rolling Bearings - NACHI

1 CMYKP recision Rolling Bearings Bearings -Cover( ).qxd 0:21 PM Page 3 CMYKA ngular Contact Ball Bearings / Flush Ground TypeU and DU Series 2 Boundary Dimensions5 Preload3 Tolerance23 Angular Contact Ball Bearings / High Speed TypeBNH Series7 Boundary Dimensions8 Preload7 Tolerance 23 Angular Contact Ball Bearings / For Thrust LoadTAH and TBH Series9 Boundary Dimensions10 Preload 9

2 Tolerance 9, 23 Double Row Cylindrical Roller BearingsNN and NNU Series12 Boundary Dimensions 13 Clearance 12 Tolerance 23 Cross Tapered Roller BearingsXRN Series15 Boundary Dimensions 17 Tolerance

3 16 Displacement 16 Ball Screw Support BearingsTAB Series19 Boundary Dimensions 21 Tolerance 20 Preload 20 Displacement 19 Tolerance Values for Radial Bearings23 Bearings -Body( ).

4 Qxd 0:36 PM Page 2 Angular Contact Ball Bearings / Flush Ground TypeAngular Contact Ball Bearings / Flush Ground TypeU and DU Series2 FeaturesCombinationsAny Combination of NACHI FLUSH GROUNDP recision Beanings will provide the desired preload,obviously facilitating bearing are three basic combinations:* Back to back combination (DB)* Face to face combination (DF)* Tandem combination (DT)which require no adjustment so the optimumcombination for an application may be combination can be readily assembled; because these areuniversal type Bearings , DB, DF and DT combinations as wellas multi-combinations can be combinations can be simplified; if the inner and outer ringspacer widths are the same, the bearing can be readily assembledwith the desired Bearings in various combinations is unnecessary; thereis no need to keep DB, DF or DT combinations in is sufficient to stock the preloaded U or DU series.

5 Overallinventory will be reduced and its control will be (DB)(DF)(DT)"U" SeriesA "U" bearing can be purchased singularly."DU" SeriesTo manufacture a "DU" series set, select two "U" series Bearings . Thesehave been manufactured with the desired preload. They are purchasablewith a small dimensional variation in bore diameter and outer such they can be combined to make a DB, DF or DT ; U=Universal, DU=Duplex universalCMYK Bearings -Body( ).qxd 0:36 PM Page 3 Angular Contact Ball Bearings / Flush Ground TypeFlush Ground TypeU and DU Series3 DesignationSelection criteria for preloadPreloadIn ordinary operation, Rolling Bearings have contact ball Bearings may be assembledwith a small amount of axial load, which is referredto as "preload".

6 This preload, when properly appliedcan improve bearing performance. However,improperly applied, it can cause adverse effects,such as increased torque, temperature rise, noiseand reduced service life. Generally the "preload"provides the following effects:1 Since axial displacement due to external forceis reduced, shaft rigidity increases, resulting inhigh rotational accuracy and reduced vibration,promoting noise-free Increased shaft rigidity improves possibility of fretting corrosion caused byexternal vibration is wear will not result in an immediatereduction in elements rotate Bearings are not adversely affected bygyromoment or centrifugal If the proper amount of preload is applied,maximum Rolling element loads are reduced.

7 Andbearing life is , preload is applied to angular contactball Bearings using springs or matched spacers. It isrecommended that factory-combined and adjustedbearings be used. Our standard preloads for combinedangular contact ball Bearings are shown the desired standard preload, according to thecriteria given in the following U /GL P4 Basic numberAccuracy symbolP5 : class 5P4 : class 4 Series symbolU : single bearingDU : duplex bearingPreload rating symbol/GE : extra light preload/GL : light preload/GM : medium preload/GH : heavy preloadRemark.

8 Suffix"Y"next to Basicnumber,indicates"Nylon cage"being symbolELMHS election criteriaTo prevent machine vibration and increase accuracyTo provide rigidity at high-speed(dmn500000) operationTo provide greater rigidity than the "L" preload at medium-speed operationTo provide maximum rigidity at low-speed operationCMYK Bearings -Body( ).qxd 0:36 PM Page 4 Angular Contact Ball Bearings / Flush Ground Type4 DBDFFFBBFF000102030405060708091011121314 1516171819202050701001451952570100135195 2655010014519529539070135195265390540100 1952953905907851352653905407851080145295 3905907851170147019539054078510801570196 0 DBDFEFFBBFFDBDFLFFBBFFDBDFMFFBBFFDBDFHFF BBFFR ecommended preload for 7000CU seriesUnit : preload for 7200CU seriesUnit : Bearings -Body( ).

9 Qxd 0:36 PM Page 5 Angular Contact Ball Bearings / Flush Ground TypeFlush Ground TypeU and DU Series5 DBrrad15 rr1 Single2 BDuplex(DT-mounting)RR1 RRRdD Br -2 7209CU7209 CDU41000665005080161 1 1 1 1 dimensions(mm) bearing numberBasic dynamic loadratings Cr (N)Load Center(mm)CMYK Bearings -Body( ).qxd 0:36 PM Page 6 Angular Contact Ball Bearings / Flush Ground Type6D1Rd2d1D1 Single or DT-mounted bearingRRRD1Rd2d2D1DB-mounted bearingRR11R1D1Rd1d1D1DF-mounted bearingRRRRRRRB asic static loadratings Cor (N)Speed ratings ( )Mass (kg)

10 SinglebearingBasicnumber2500500044000350 006100049000122425 1 1 1 1 1 1 1 1 1 1 1 1 7213C43000865008900710012000960076104106 1 7214C46000920008400670012000960081109111 1 7215C55500111000780062001100088008611912 1 1 2 1 7216C59000118000740059001000080009112412 6 1 2 1 7018C10500021100064005100880070001001501 54 2 1 7019C11500023000060004800830066001071581 63 2 1 7020C12800025500057004600790063001121681 73 2 1 7220 CAbutment and fillet dimensions (mm)SingleDuplexSingleDuplexSingleDuplex D1(min.)