7 Tapered roller bearings

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2 7 Tapered roller bearings Designs and variants Basic design bearings TQ-line bearings Bearings with a QCL7C designation suffix Application specific bearings Bearings with a flanged outer ring Matched bearings Cages Performance classes SKF Explorer bearings SKF Energy Efficient (E2) bearings Bearing data (Dimension standards, tolerances, internal clearance, preload, misalignment, friction, defect frequencies) Loads (Minimum load, equivalent loads) Calculating the axial load for bearings mounted singly or paired in tandem Calculating the radial load acting on matched bearings Temperature limits Product tables 7.1 Metric single row tapered roller bearings Inch single row tapered roller bearings Single row tapered roller bearings with a flanged outer ring Matched bearings arranged face-to-face Matched bearings arranged back-to-back Matched bearings arranged in tandem Other tapered roller bearings Bearings with Solid Oil SKF DryLube bearings Double row tapered roller bearings skf.com/bearings Four-row tapered roller bearings skf.com/bearings Hub bearing units for passenger cars contact SKF Hub bearing units for trucks.. contact SKF Tapered roller bearing units for rail-bound vehicles contact SKF Units for transmission and engine applications contact SKF Permissible speed Design of bearing arrangements Fits for inch bearings Fits for matched bearings Adjustment procedure Bearing designations Metric bearings Inch bearings Designation system

3 7 Tapered roller bearings Designs and variants Tapered roller bearings have tapered inner and outer ring raceways and tapered rollers. They are designed to accommodate combined loads, i.e. simultaneously acting radial and axial loads. The projection lines of the raceways meet at a common point on the bearing axis ( fig. 1) to provide true rolling and low friction. The axial load carrying capacity of tapered roller bearings increases with increasing contact angle a. The size of the angle is related to the calculation factor e ( product tables): the larger the value of e, the larger the contact angle. A single row tapered roller bearing is typically adjusted against a second tapered roller bearing. Single row tapered roller bearings are separ able ( fig. 2), i.e. the inner ring with roller and cage assembly (cone) can be mounted separately from the outer ring (cup). The factors that influence SKF bearing performance and service life include but are not limited to the following: More information Bearing life and load ratings Design considerations Bearing systems Recommended fits Abutment and fillet dimensions Lubrication Mounting, dismounting and bearing care Mounting instructions for individual bearings skf.com/mount SKF bearing maintenance handbook (ISBN ) roller end / flange contact area The geometry and surface finish of the roller ends and the area on the flange that makes contact with the roller ends ( fig. 3) have been optimized to promote and maintain the formation of a lubricant film. This reduces friction and frictional heat as well as flange wear. The bearings can better maintain preload and run at reduced noise levels. raceway profiles To extend service life under misalignment or heavy load conditions, SKF tapered roller bearings have either crowned raceways or a logarithmic profile to prevent stress peaks at the roller ends. The logarithmic profile is designed to optimize load distribution along the rollers. consistency of profiles and roller size The rollers used in SKF tapered roller bearings are made to such close tolerances that they are virtually identical. These extremely close tolerances, together with the precision of the raceway profiles, provide optimal load distribution over the rollers to reduce noise and vibration levels and enable preload to be set more accurately. a a Fig

4 Designs and variants Running-in Tapered roller bearings typically have a running-in period. During the running-in period, a conventional design tapered roller bearing experiences a significant amount of friction, resulting in wear, which can be noticed as a temperature spike ( diagram 1). With current SKF tapered roller bearing designs, friction, wear and frictional heat are significantly reduced, provided the bearings are mounted and lubricated correctly. Diagram 1 Typical temperature gradation of tapered roller bearings during the running-in period (approximate values) Temperature [ C ( F)] 150 (300) 100 (210) 50 (120) Conventional design bearings SKF basic design bearings SKF Explorer bearings and TQ-line bearings (designation suffix Q) SKF Energy Efficient bearings 0 (30) Operating hours [h] 7 Fig. 2 Fig

5 7 Tapered roller bearings Assortment The assortment listed in this catalogue comprises popular sizes of metric single row tapered roller bearings in accordance with ISO 355 and inch bearings in accordance with ANSI/ABMA Standard It includes: basic design bearings TQ-line bearings (designation suffix Q) bearings with a flanged outer ring matched bearings Tapered roller bearings listed in this catalogue constitute the basic SKF assortment and are only part of the total assortment. For information about other sizes of single row tapered roller bearings, refer to the product information available online at skf.com/bearings. double row and four-row tapered roller bearings, refer to the product information available online at skf.com/bearings. hub units based on tapered roller bearings for industrial, automotive, railway and offhighway applications, contact SKF. Basic design bearings The design and internal geometry of SKF basic design tapered roller bearings ( fig. 4) enable these bearings to provide long service life. The crowned profile of the raceways and optimized surface finish of the inner ring guide flange enables these bearings to run cooler and consume less lubricant than conventional design bearings. TQ-line bearings TQ-line tapered roller bearings ( fig. 4) are identified by the designation suffix Q and have operating characteristics that clearly set them apart from bearings made to conventional designs. The logarithmic contact profile provides optimum load distribution in the roller / raceway contact area to keep stress peaks within acceptable limits, even under slight misalignment. Like SKF Explorer bearings, the roller end / flange contact area of TQ-line tapered roller bearings is designed to reduce friction and wear at start-up. Normally the bearings do not need running-in procedures after installation. Bearings that are preloaded experi ence only a small, controlled loss of initial preload. Bearings with a QCL7C designation suffix Bearings identified by the designation suffix QCL7C were originally designed for use as pinion bearings in the differential of industrial transmissions to provide a constant, accurate gear mesh. The bearings are characterized by their high degree of running accuracy and high preload capability. They have special friction characteristics and can be axially adjusted within narrow limits using the friction-torque method. Their internal design promotes the formation of a hydrodynamic oil film to substantially reduce friction and consequently operating temperature during the running-in period. When installed, lubricated and maintained properly, bearings with a designation suffix QCL7C retain their preload setting. Fig

6 Designs and variants Application specific bearings For applications where the bearings are subjected to unique operating conditions, SKF can customize TQ-line bearings (designation suffix Q) to meet the needs of that particular application. For additional information about application specific tapered roller bearings, contact the SKF application engineering service. Bearings with a flanged outer ring Certain sizes of SKF single row tapered roller bearings are also available with a flange on the outer ring ( fig. 5). Bearings with a flanged outer ring are relatively easy to locate axially in the housing. The housing bore is also easier and more cost-effective to manufacture, as shoulders are not required. 7 Fig

7 7 Tapered roller bearings Matched bearings Matched bearings ( fig. 6) can be supplied for bearing arrangements where the load carrying capacity of a single bearing is in adequate, or where the shaft has to be located axially in both directions with a specific axial clearance or preload. The bearings and ring spacer(s) are matched in production and delivered as a set. When mounted, the radial load is evenly distributed between the bearings. Depending on the requirements, matched bearings can be supplied in face-to-face, backto-back, or tandem arrangements ( fig. 7). The matched bearings listed in this catalogue constitute the basic SKF assortment. Other matched bearings can be supplied on request. Matched bearings arranged face-to-face Matched bearings arranged face-to-face ( fig. 7) have load lines that converge toward the bearing axis. Therefore, the arrangement can accommodate a limited amount of misalignment. Axial loads in both directions can be accommodated, but only by one bearing in each direction. The bearing set is supplied with an intermedi ate outer ring spacer. Matched bearings arranged back-to-back Matched bearings arranged back-to-back ( fig. 7) have load lines that diverge toward the bearing axis to provide a relatively stiff bearing arrangement that can also accommo- Fig. 6 date tilting moments. Axial loads in both directions can be accommodated, but only by one bearing in each direction. The bearing set is supplied with intermediate inner and outer ring spacers. Matched bearings arranged in tandem Matched bearings arranged in tandem ( fig. 7) have load lines that are parallel. Radial and axial loads are shared equally by the bearings. This arrangement is used when the load carrying capacity of a single bearing is inadequate. However, matched bearings arranged in tandem can accommodate axial loads in one direction only. If axial loads act in both directions, a third bearing, adjusted against the tandem pair, must be added. Fig. 7 Face-to-face arrangement Back-to-back arrangement Tandem arrangement 802

8 Designs and variants The bearing set is supplied with intermediate inner and outer ring spacers. Cages SKF tapered roller bearings are fitted with stamped steel cages as standard. Bearings with polymer cages are available on request ( table 1). The lubricants generally used for rolling bearings do not have a detrimental effect on cage properties. However, some synthetic oils and greases with a synthetic oil base and lubricants containing a high proportion of EP additives, when used at high temperatures, can have a detrimental effect on polyamide cages. For additional information about the suitability of cages, refer to Cages ( page 37) and Cage materials ( page 152). 7 Table 1 Cages for tapered roller bearings Cage type Window-type, roller centred Material Stamped steel PA66, glass fibre reinforced PEEK, glass fibre reinforced Suffix J1, J2 or J3 TN9 TNH 803

9 7 Tapered roller bearings Performance classes SKF Explorer bearings In response to the ever-demanding performance requirements of modern machinery, SKF developed the SKF Explorer performance class of rolling bearings. SKF Explorer tapered roller bearings realized this substantial improvement in performance by optimizing the internal geometry and surface finish of all contact surfaces, combining the extremely clean and homogenous steel with a unique heat treatment, optimizing the roller end / flange contact area and cage and improving the roller profile and the quality and dimensional consistency of the rollers. These improvements provide the following benefits: higher load carrying capacity improved wear-resistance reduced noise and vibration levels less frictional heat significantly extended bearing service life SKF Explorer bearings reduce environmental impact by enabling downsizing and reducing both lubricant and energy use. Just as importantly, SKF Explorer bearings can reduce the need for maintenance and contribute to increased productivity. SKF Explorer bearings are shown with an asterisk in the product tables. The bearings retain the designation of earlier standard bearings. However, each bearing and its box are marked with the name SKF Explorer. Other standard SKF tapered roller bearings can be manufactured in the SKF Explorer performance class on request. These bearings are identified by the designation suffix PEX. SKF Energy Efficient (E2) bearings To meet the ever-increasing demand to reduce friction and energy use, SKF has developed the SKF Energy Efficient (E2) performance class for rolling bearings. SKF E2 tapered roller bearings are characterized by a frictional moment in the bearing that is at least 30% lower when compared to a same-sized standard SKF bearing. The bearings realized this substantial reduction of the frictional moment mainly by optimizing the internal geometry, number of rollers, surface finish and redesigning the cage. Reduced operating temperatures improve lubrication conditions and enable extended lubrication intervals or higher speeds. The lower mass of the roller and cage assembly and reduced inertial forces in the bearing reduce the risk of skidding and smearing. Typ ical applications include wind energy transmissions, railway transmissions, ship transmissions and other heavy industrial transmissions. Typically, SKF E2 tapered roller bearings are available on request. For additional information, contact the SKF application engineering service. 804

10 Performance classes 7 805

11 7 Tapered roller bearings Bearing data / single row tapered roller bearings Metric series Dimension standards Tolerances Boundary dimensions: ISO 355 Bearings with a J designation prefix: ANSI/ABMA Standard 19.1 Normal, improved running accuracy for bearings with a CL7C designation suffix Check availability of reduced width tolerance to CLN Bearings with a J designation prefix: CLN Bearings with D > 420 mm: Normal dimensional accuracy P6 running accuracy For additional information ( page 132) Internal clearance For additional information ( page 149) Preload For additional information ( page 214) Misalignment Values: ISO 492 ( tables 6 and 7, pages 140 and 141) P6 values: DIN 620-3:1964 (withdrawn in 1988) The inner rings with roller and cage assembly and outer rings of SKF single row tapered roller bearings with the same basic Obtained after mounting, depending on adjustment Obtained after mounting, depending on adjustment TQ-line bearings (designation suffix Q), SKF Explorer and SKF E2 bearings: 2 to 4 minutes of arc. If misalignment cannot be The permissible angular misalignment between the inner and outer rings depends on the size and internal design of the bearing, the radial internal clearance in operation and the forces and moments acting on the Friction, starting torque, power loss Defect frequencies Frictional moment, starting torque and power loss can be calculated as specified under Friction ( page 97), or Defect frequencies can be calculated using the tools available 806

12 Bearing data Inch series Boundary dimensions: AFBMA Standard 19 (ANSI B3.19) ANSI/ABMA Standard 19.2 has replaced the above standard, but does not include dimensions. Normal, improved running accuracy for bearings with a CL7C designation suffix Check availability CL3, CL0 or reduced width tolerance Deviating width tolerances for cups and cones are identified by a designation suffix ( table 2, page 809). Values: ANSI/ABMA Standard 19.2 ( table 9, page 143) 7 designation are interchangeable. The tolerance for the total abutment width T of the bearing is not exceeded if the cups and cones are interchanged. against a second bearing. against a second bearing. avoided, SKF recommends not to use basic design bearings. bearing. As a result, only approximate values are listed here. Any misalignment increases bearing noise and reduces bearing service life. using the tools available online at skf.com/bearingcalculator. online at skf.com/bearingcalculator. 807

13 7 Tapered roller bearings Bearing data / matched bearings Dimension standards Tolerances For additional information ( page 132) Internal clearance For additional information ( page 149) Misalignment Friction, starting torque, power loss Defect frequencies Boundary dimensions: ISO 355 (individual bearing) Normal Values: ISO 492 ( table 6, page 140) Total width tolerances: not standardized ( table 3) Standard: table 4, page 810 Other clearances are identified by the designation suffix C. Values apply to unmounted bearing sets under measuring loads of: D 90 mm 0,1 kn 90 < D 240 mm 0,3 kn D > 240 mm 0,5 kn If misalignment cannot be avoided, SKF recommends using a face-toface arrangement. Any misalignment increases bearing noise and reduces bearing service life. Frictional moment, starting torque and power loss can be calculated as specified under Friction ( page 97), or using the tools available online at skf.com/bearingcalculator. Defect frequencies can be calculated using the tools available online at skf.com/bearingcalculator. 808

14 Bearing data Deviating width tolerances of cups and cones for inch bearings Designation Width tolerance 1) suffix max. min. µm Table 2 / /1A / / / / /2B /2C / / / / / ) The total width tolerance for a complete bearing is equal to the sum of the tolerances for the cup and cone. 7 Table 3 Total width tolerances of matched metric single row tapered roller bearings Bore diameter Total width tolerance D TsD of matched bearings in the series , 302, 303, , 332 d D TsD D TsD D TsD D TsD D TsD D TsD over incl. high low high low high low high low high low high low mm µm D TsD designates the deviation of a single total abutment width of a matched bearing set from the nominal. 809

15 7 Tapered roller bearings Axial internal clearance of matched metric single row tapered roller bearings, arranged face-to-face or back-to-back Table 4 Bore diameter Axial internal clearance of matched bearings in the series , 302, 322, , d over incl. min. max. min. max. min. max. min. max. min. max. min. max. mm µm

16 Loads Loads Single row tapered roller bearings Matched bearings Minimum load F rm = 0,02 C SKF Explorer and SKF E2 bearings F rm = 0,017 C For additional information ( page 86) The weight of the components supported by the bearings, together with external forces, generally exceed the requisite minimum load. If this is not the case, the bearings must be subjected to an additional radial load or axial preload. Equivalent dynamic bearing load For additional information ( page 85) F a /F r e P = F r F a /F r > e P = 0,4 F r + Y F 1) a Face-to-face or back-to-back arrangement: F a /F r e P = F r + Y 1 F a F a /F r > e P = 0,67 F r + Y 2 F a Tandem arrangement 1) : F a /F r e P = F r F a /F r > e P = 0,4 F r + Y F a 7 Equivalent static bearing load P 0 = 0,5 F r + Y 0 F a 1) Face-to-face or back-to-back arrangement: P 0 = F r + Y 0 F a For additional information ( page 88) P 0 < F r P 0 = F r Tandem arrangement 1) : P 0 = 0,5 F r + Y 0 F a Symbols C = basic dynamic load rating [kn] ( product tables) e = calculation factor ( product tables) F a = axial load [kn] F r = radial load [kn] F rm = minimum radial load [kn] P = equivalent dynamic bearing load [kn] P 0 = equivalent static bearing load [kn] Y, Y 0, Y 1, Y 2 = calculation factors ( product tables) 1) When determining the axial load F a, refer to Calculating the axial load for bearings mounted singly or paired in tandem ( page 812). 811

17 7 Tapered roller bearings Calculating the axial load for bearings mounted singly or paired in tandem When a radial load is applied to a single row tapered roller bearing, the load is transmitted from one raceway to the other at an angle to the bearing axis and an internal axial load is induced. This must be considered when calculating the equivalent bearing loads for bearing arrangements consisting of two single bearings and/or bearing pairs arranged in tandem. The necessary equations are provided in table 5 for various bearing arrangements and load cases. The equations are only valid if the bearings are adjusted against each other to practically zero clearance, but without any preload. In the arrangements shown, bearing A is subjected to a radial load F ra and bearing B to a radial load F rb. Both F ra and F rb are always considered positive, even when they act in a direction opposite to what is shown in the figures. The radial loads act at the pressure centres of the bearings ( distance a in the product tables). K a is the external axial force acting on the shaft or on the housing. Load cases 1c and 2c are also valid when K a = 0. Values of the factor Y are listed in the product tables. 812

18 Loads Table 5 Axial loading of bearing arrangements incorporating two single row tapered roller bearings and/or bearing pairs in tandem Bearing arrangement Load case Axial loads Case 1a Back-to-back B A F ra F rb 0,5 F F rb Y A Y aa = B YA K a 0 F ab = F aa + K a K a Case 1b F rb F ra F ra F < rb 0,5 F F rb Y A Y aa = B YA F ab = F aa + K a Face-to-face A B q F rb F ra w K a 0,5 < Y B Y A z Case 1c 7 K a F ra F < rb 0,5 F F Y A Y aa = F ab K a F rb ab = B YB F ra F rb q F rb F ra w K a < 0,5 < Y B Y A z Case 2a Back-to-back B A F ra F rb 0,5 F F Y A Y ab = F ab + K a F rb aa = B YA K a 0 K a Case 2b F rb F ra F ra F > rb 0,5 F F Y A Y aa = F ab + K a F rb ab = B YB Face-to-face A B q F rb F ra w K a 0,5 < Y B Y A z Case 2c K a F ra F > rb 0,5 F F ra Y A Y aa = B YA F ab = F aa K a F ra F rb q F ra F rb w K a < 0,5 < Y A Y B z 813

19 7 Tapered roller bearings Calculating the radial load acting on matched bearings When matched tapered roller bearings, arranged face-to-face or back-to-back, are mounted together with a third bearing, the bearing arrangement is statically indeterminate. In these cases, the radial load F r acting on the bearing pair must be calculated first. Matched bearings arranged face-to-face For matched bearings, where two bearings are arranged face-to-face ( fig. 8), it can be assumed that the radial load acts at the geometric centre of the matched bearings, as the distance between the pressure centres of the two bearings is short when compared with the distance between the geometric centres of the set and the other bearing. In this case, it can be assumed that the bearing arrangement is statically determined. Matched bearings arranged back-to-back The distance a between the pressure centres of two matched bearings arranged back-toback is significant when compared with the distance L between the geometric centres of the matched bearings and the other bearing ( fig. 9). Therefore, it is necessary to calculate the magnitude of the load acting on the bearing pair and also the distance a 1 at which the load acts. The magnitude of the radial load can be obtained using L 1 F r = K r L a 1 where F r = radial load acting on a bearing pair [kn] K r = radial force acting on the shaft [kn] L = distance between the geometric centres of the two bearing positions [mm] L 1 = distance between the centre of bearing position! and the point of action of the force K r [mm] a = distance between the bearing pressure centres [mm] a 1 = distance between the geometric centre of the matched bearings, and the point of action of the radial load F r [mm] The distance a 1 can be determined using diagram 2. The distance of the pressure centres a and the calculation factor Y 2 are listed in the product tables. Fig. 8 F r 814

20 Loads Fig. 9!!! L K a = F a a 1 0 F r 7 K r L 1 a Diagram 2 0,5 a 1 a 0,4 0,3 0,2 0, ,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0 F a 1,5 Y 2 F r 815

21 7 Tapered roller bearings Temperature limits The permissible operating temperature for tapered roller bearings can be limited by: the dimensional stability of the bearing rings and rollers the cage the lubricant When temperatures outside the permissible range are expected, contact the SKF application engineering service. Bearing rings and rollers SKF tapered roller bearings undergo a special heat treatment. The bearings are heat sta bilized up to: D 160 mm D > 160 mm 120 C (250 F) 150 C (300 F) Cages Steel or PEEK cages can be used at the same operating temperatures as the bearing rings and rollers. For temperature limits of cages made of other polymer materials, refer to Cage materials ( page 152). Lubricants Temperature limits for SKF greases are provided under Lubrication ( page 239). When using lubricants not supplied by SKF, the temperature limits should be evaluated according to the SKF traffic light concept ( page 244). Design of bearing arrangements Single row tapered roller bearings must either be used with a second bearing or as a matched pair ( fig. 10). The bearings must be adjusted against each other until the requisite clearance or preload is obtained ( Bearing preload, page 214). To maximize bearing performance and operational reliability, the appropriate clearance or preload must be selected and then applied during the mounting process. When the operating clearance in a bearing arrangement is too large, the load carrying cap acity of both bearings cannot be fully utilized. Excessive preload increases friction, which increases the amount of frictional heat and reduces bearing service life. Fits for inch bearings In contrast to metric bearings, which are machined to a minus tolerance, inch bearings are machined to a plus tolerance ( table 9, page 143). Therefore, the deviations for shaft and housing diameters for metric bearings are not applicable. Suitable fits for inch bearings can be obtained from the recommended fits for metric bearings. Tables 6 and 7 ( pages 818 and 819) provide the shaft and housing fits for inch tapered roller bearings that are valid for Normal tolerance bearings in typical applications. Permissible speed The permissible speed can be estimated using the speed ratings listed in the product tables and applying the information provided under Speeds ( page 117). 816

22 Design of bearing arrangements Fits for matched bearings The axial internal clearance of matched bearings arranged face-to-face or back-to-back ( table 4, page 810) provides an appropriate operating clearance when the bearings are mounted on shafts machined to: d 140 mm m5 E 140 mm < d 200 mm n6 E d > 200 mm p6 E These shaft seat tolerance classes are recommended for normal to heavy rotating loads on the inner ring. If tighter fits are selected, be sure that the bearings are not clamped and that they are able to rotate freely. For addition al information about shaft tolerances, contact the SKF application engineering service. For stationary outer ring loads, the recommended housing bore tolerance class is J6 E or H7 E. 7 Adjustment procedure When adjusting tapered roller bearings against each other, the bearings must be rotated so that the rollers assume their correct position, i.e. the large end face of the rollers must be in contact with the guide flange. Fig. 10 Single bearings back-to-back Matched bearings face-to-face Matched bearings back-to-back 817

23 7 Tapered roller bearings Table 6 Shaft diameter deviations for inch bearings Nominal Deviations for fits with clearance/interference according to diameter Shaft seat f6 E g6 E h6 E j6 E js6 E k6 E Bearing bore over incl. high low high low high low high low high low high low mm µm , , , , Nominal Deviations for fits with clearance/interference according to diameter Shaft seat m6 E n6 E p6 E r6 E r7 E s7 E min ± IT7/2 Bearing bore over incl. high low high low high low high low high low high low mm µm , , , , For nominal diameter ranges not listed or higher requirements on accuracy, contact the SKF application engineering service. 818

24 Design of bearing arrangements Table 7 Housing bore diameter deviations for inch bearings Nominal Deviations for fits with clearance/interference according to diameter Housing bore seat F7 E G7 E H7 E H8 E J7 E Bearing outside diameter over incl. high low high low high low high low high low mm µm , , , , , , , Nominal Deviations for fits with clearance/interference according to diameter Housing bore seat K7 E M7 E N7 E P7 E Bearing outside diameter over incl. high low high low high low high low mm µm , , , , , , , For higher requirements on accuracy, contact the SKF application engineering service. 819

25 7 Tapered roller bearings Bearing designations Metric bearings The designations of metric tapered roller bearings follow one of the following principles: The series designations in accordance with ISO 355 consist of a digit and two letters. The digit represents the contact angle. The two letters represent the diameter and width series, respectively. This is followed by a three-digit bore diameter d [mm]. The basic designations of SKF tapered roller bearings start with the letter T, e.g. T2ED 045. Designations established prior to 1977 are based on the system shown under Basic designations, e.g ( diagram 2, page 43). Metric bearings with the designation prefix J follow the ABMA designation system which is used for inch bearings ( ANSI/ABMA Standard 19.2). 820

26 Bearing designations Inch bearings Inch tapered roller bearing designations are in accordance with ANSI/ABMA All inch bearings within a series use the same roller and cage assembly but the inner and outer rings can have different sizes and designs. Any inner ring with roller and cage assembly (cone) can be assembled with any outer ring (cup) belonging to the same bearing series. For this reason, the cup and cone have individual designations and can be supplied separately ( fig. 11). The designations of cups and cones as well as the series consist of a threeto six-digit number which may be prefixed to characterize a bearing series from extra-light to extra-heavy. The complete bearing designation consists of the cone designation followed by that of the cup. The two designations are separated by an oblique stroke. To shorten the complete bearing designations, abbreviations are used ( table 8). Fig Examples of inch tapered roller bearing designations Table 8 Complete bearing Cone Cup Series LM 11749/710/Q 1) LM 11749/Q LM 11710/Q LM JL F/710 1) JL F JL JL HM 89449/2/410/2/QCL7C 1) HM 89449/2/QCL7C HM 89410/2/QCL7C HM H /810/CL7C 1) H /CL7C H /CL7C H /2/4535/2/Q 2) 4580/2/Q 4535/2/Q /9220/CL7C 2) 9285/CL7C 9220/CL7C ) Complete bearing designation abbreviated (latest ABMA designations) 2) Complete bearing designation not abbreviated (earlier ABMA designations) 821

27 7 Tapered roller bearings Designation system Group 1 Group 2 Group 3 / Prefixes E2. SKF Energy Efficient bearing J Metric bearing following the ABMA designation system (ANSI/ABMA Standard 19.2) T Metric bearing in accordance with ISO 355 Basic designation Refer to Bearing designations ( page 820) Suffixes Group 1: Internal design B Steep contact angle Group 2: External design (seals, snap ring groove etc.) R T.. X Flanged outer ring A number immediately following the T identifies the total width of matched bearings, arranged back-to-back or in tandem. Boundary dimensions changed to conform to ISO Group 3: Cage design J.. TN9 TNH Stamped steel cage, roller centred. A number following the J indicates a different cage design. Glass fibre reinforced PA66 cage, roller centred Glass fibre reinforced PEEK cage, roller centred Group 4.1: Materials, heat treatment HA1 HA3 HN1 HN3 Case-hardened inner and outer rings Case-hardened inner ring Inner and outer rings with special surface heat treatment Inner ring with special surface heat treatment 822

28 Designation system Group Group 4.6: Other variants CL7A Pinion bearing, superseded by CL7C CL7C High-performance design CLN Reduced tolerances for ring widths and total (abutment) width in accordance with ISO tolerance class 6X PEX SKF Explorer bearing on customer request Q Optimized contact geometry and surface finish V001 CL7C and /2 VA321 Optimized internal design VA606 Crowned raceway on the outer ring, logarithmic profile on the inner ring and special heat treatment VA607 Same as VA606, but other outside diameter tolerance VC027 Modified internal geometry for increased permissible misalignment VC068 Increased running accuracy and special heat treatment VQ051 Modified internal geometry for increased permissible misalignment VQ267 Reduced inner ring width tolerance to ± 0,025 mm VQ495 CL7C with reduced or shifted tolerance range for the outside diameter VQ506 Reduced inner ring width tolerance VQ507 CL7C with reduced or shifted tolerance range for the outside diameter VQ523 CL7C with reduced inner ring width tolerance and reduced or shifted tolerance range for the outside diameter VQ601 Accuracy to ABMA tolerance class 0 for inch bearings VB022 Chamfer dimension of large outer ring side face 0,3 mm VB026 Chamfer dimension of large inner ring side face 3 mm VB061 Chamfer dimension of large inner ring side face 8 mm VB134 Chamfer dimension of large inner ring side face 1 mm VB406 Chamfer dimension of large inner ring side face 3 mm and of large outer ring side face 2 mm VB481 Chamfer dimension of large inner ring side face 8,5 mm VE174 One locating slot in the large side face of the outer ring, improved running accuracy 7 Group 4.5: Lubrication Group 4.4: Stabilization Group 4.3: Bearing sets, matched bearings DB.. DF.. DT.. Two bearings matched for mounting back-to-back. A number immediately following the DB identifies the design of the ring spacers. Two bearings matched for mounting face-to-face. A number immediately following the DF identifies the design of the ring spacer. Two bearings matched for mounting in tandem. A number immediately following the DT identifies the design of the ring spacers. Group 4.2: Accuracy, clearance, preload, quiet running /1 w /-1 s s to s /-3 s /4 c C CL0 CL00 P5 U.. W f Deviating width tolerances of cups and cones for inch bearings, ( table 2, page 809) Special clearance. The two- or three-digit number immediately following the C is the mean axial internal clearance in µm. The range remains the same as specified in table 4 ( page 810). Accuracy to ABMA tolerance class 0 for inch bearings Accuracy to ABMA tolerance class 00 for inch bearings Dimensional and running accuracy to P5 tolerance class U combined with a one- or two-digit number identifies reduced total width tolerance, e.g.: U2 +0,05/0 mm U4 +0,10/0 mm Modified ring width tolerance to +0,05/0 mm 823

29 7.1 Metric single row tapered roller bearings d mm T C r 4 r 3 r 1 r 2 D B d d 1 a Principal Basic load Fatigue Speed ratings Mass Designation Dimension dimensions ratings dynamic static load limit Reference Limiting series to ISO 355 d D T C C 0 P u speed speed (ABMA) mm kn kn r/min kg ,25 22,4 20 2, , J2 2FB , ,6 1, , J2 2DB 47 15,25 28,1 25 2, , J2 2FB 47 20,25 34,7 33,5 3, , J2/Q 2FD ,2 27 2, , X/Q 3CC 47 15,25 27, , J2/Q 2DB 52 16,25 34,1 32,5 3, , J2/Q 2FB 52 22, , , J2/Q 2FD ,1 29 2, ,1 320/22 X 3CC ,5 3, , X/Q 4CC 52 16,25 30,8 33,5 3, , J2/Q 3CC 52 19,25 35,8 44 4, , BJ2/Q 5CD , , /Q 2CE 62 18,25 44,6 43 4, , J2/Q 2FB 62 18, , , J2 7FB 62 25,25 60,5 63 7, , J2 2FD , ,14 320/28 X/Q 4CC 58 17, ,5 4, ,2 302/28 J2 3DC 58 20,25 41,8 50 5, ,25 322/28 BJ2/Q 5DD ,8 44 4, , X/Q 4CC 62 17,25 40,2 44 4, , J2/Q 3DB 62 21,25 49,5 58,5 6, , BJ2/QCL7CVA606 5DC 62 21,25 50,1 57 6, , J2/Q 3DC ,4 76,5 8, , /Q 2DE 72 20,75 56,1 56 6, , J2/Q 2FB 72 20,75 47,3 50 5, , J2/Q 7FB 72 28,75 76,5 85 9, , J2/Q 2FD , ,5 3, ,11 JL F/710 (L 26700) ,9 46,5 4, ,19 320/32 X/Q 4CC 824

30 C a C b D a d a d b D b r a r b Dimensions Abutment and fillet dimensions Calculation factors d d 1 B C r 1,2 r 3,4 a d a d b D a D a D b C a C b r a r b e Y Y 0 ~ min. min. max. min. min. max. min. min. min. max. max. 7.1 mm mm 15 27, ,28 2,1 1, ,35 1,7 0,9 30, ,28 2,1 1,1 30, ,28 2,1 1, , ,6 0, ,6 0,6 0,37 1,6 0,9 33, ,35 1,7 0,9 34, ,5 1, ,5 1,5 0,3 2 1,1 34, ,5 1, ,5 1,5 0,3 2 1, , ,5 0,6 0, ,5 0,6 0,6 0,4 1,5 0, , ,5 0,6 0, ,5 0,6 0,6 0,43 1,4 0, ,37 1,6 0,9 41, ,57 1,05 0,6 38, ,35 1,7 0,9 41, ,5 1, ,5 1,5 0,3 2 1,1 45, ,5 1, ,5 1,5 0,83 0,72 0,4 41, ,5 1, ,5 1,5 0,3 2 1, , ,43 1,4 0, ,37 1,6 0,9 43, ,57 1,05 0, , ,43 1,4 0,8 45, ,37 1,6 0,9 48, ,57 1,05 0,6 45, ,37 1,6 0,9 45, , , ,35 1,7 0,9 48, ,5 1, ,5 1,5 1,5 0,31 1,9 1,1 52, ,5 1, ,5 1,5 1,5 0,83 0,72 0,4 48, ,5 1, ,5 1,5 1,5 0,31 1,9 1, , ,5 3,6 1, ,3 0,33 1,8 1 46, ,46 1,3 0,7 825

31 7.1 Metric single row tapered roller bearings d mm T C r 4 r 3 r 1 r 2 D B d d 1 a Principal Basic load Fatigue Speed ratings Mass Designation Dimension dimensions ratings dynamic static load limit Reference Limiting series to ISO 355 d D T C C 0 P u speed speed (ABMA) mm kn kn r/min kg ,4 49 5, , J2/Q 4CC ,9 54 5, , X/Q 4CC 72 18,25 51,2 56 6, , J2/Q 3DB 72 24, , , J2/Q 3DC , , , /Q 2DE 80 22,75 72,1 73,5 8, , J2/Q 2FB 80 22,75 61,6 67 7, , J2/Q 7FB 80 32,75 93, , , BJ2/Q 5FE 80 32,75 95, , , J2/Q 2FE ,75 93, , , /37 BJ2/Q 5EE ,9 52 5, ,21 JL A/310/Q 3CC ,9 52 5, ,2 JL 69349/310/Q 3CC ,8 71 7, , /38 X/Q 3CC ,8 71 7, , X/Q 3CD , , , /Q 2CE 80 19,75 61,6 68 7, , J2/Q 3DB 80 24,75 74,8 86,5 9, , J2/Q 3DC , /QCL7C 2DE , ,9 T2EE 040/QVB134 2EE 90 25,25 85, , , J2/Q 2FB 90 25, ,5 9, ,72 * J2/QCL7C 7FB 90 35, , J2/Q 2FD ,3 80 8, , X/Q 3CC , , ,55 * 33109/Q 3CE 85 20, ,5 8, , J2/Q 3DB 85 24,75 91, ,58 * J2/Q 3DC , , /Q 3DE , , ,93 T7FC 045/HN3QCL7C 7FC , ,2 T2ED 045 2FD , , , J2/Q 2FB , , ,95 * J2/QCL7C 7FB , , BJ2/QCL7C 5FD , , , J2/Q 2FD * SKF Explorer bearing 826

32 C a C b D a d a d b D b r a r b Dimensions Abutment and fillet dimensions Calculation factors d d 1 B C r 1,2 r 3,4 a d a d b D a D a D b C a C b r a r b e Y Y 0 ~ min. min. max. min. min. max. min. min. min. max. max. 7.1 mm mm 35 49, ,44 1,35 0,8 49, ,46 1,3 0,7 51, ,5 1, ,5 1,5 0,37 1,6 0,9 52, ,5 1, ,5 1,5 1,5 0,37 1,6 0,9 53, ,5 1, ,5 1,5 0,35 1,7 0,9 54, , ,5 2 1,5 0,31 1,9 1,1 59, , ,5 2 1,5 0,83 0,72 0,4 59, , ,5 2 1,5 0,54 1,1 0,6 54, , ,5 2 1,5 0,31 1,9 1, , , ,5 2 1,5 0,54 1,1 0, , ,5 1,3 1, , ,5 1,3 1,3 0,43 1,4 0,8 52, ,5 3,6 1, , ,5 3,4 1,3 0,43 1,4 0,8 54, , , ,37 1,6 0, , , , ,37 1,6 0,9 57, ,5 1,5 1, ,5 1,5 1,5 0,35 1,7 0,9 57, ,5 1, ,5 1,5 1,5 0,37 1,6 0,9 58, ,5 1, ,5 1,5 1,5 0,37 1,6 0,9 59, ,5 1, ,5 1,5 0,35 1,7 0,9 61,2 32, ,35 1,7 0,9 62, , ,5 0,35 1,7 0,9 67, , ,5 0,83 0,72 0,4 62, , ,5 0,35 1,7 0, , , , ,4 1,5 0, ,5 1,5 1, ,5 1,5 1,5 0,37 1,6 0,9 63, ,5 1, ,5 1,5 1,5 0,4 1,5 0,8 64, ,5 1, ,5 1,5 1,5 0,4 1,5 0,8 65, ,5 1, ,5 1,5 0,4 1,5 0,8 73,5 26,5 20 2,5 2, ,5 2,5 0,88 0,68 0,4 68, ,5 2, ,5 2,5 0,33 1,8 1 70, , ,5 0,35 1,7 0,9 74, , ,5 0,83 0,72 0,4 74, , ,5 0,54 1,1 0,6 71, , ,5 0,35 1,7 0,9 827

33 7.1 Metric single row tapered roller bearings d mm T C r 4 r 3 r 1 r 2 D B d d 1 a Principal Basic load Fatigue Speed ratings Mass Designation Dimension dimensions ratings dynamic static load limit Reference Limiting series to ISO 355 d D T C C 0 P u speed speed (ABMA) mm kn kn r/min kg ,1 71 7, ,3 LM /310/QCL7C (LM ) ,5 88 9, , X/Q 3CC ,5 88 9, , X/QCL7CVB026 3CC , , , /Q 2CE 82 21,5 72, ,43 JLM AA/910 AA/Q 2CC , , , /Q 3CE 90 21,75 76,5 91,5 10, , J2/Q 3DB 90 24,75 82, , , J2/Q 3DC ,75 JM /110 A/Q (M ) ,75 JM /110/Q 2DD , , /Q 3DE , ,3 T2ED 050/Q 2ED ,25 T7FC 050/QCL7C 7FC , , ,25 * J2/Q 2FB , , ,2 * J2/QCL7C 7FB , , ,95 * BJ2/QCL7C 5FD , , J2/Q 2FD , , , X/Q 3CC , ,66 * 33011/Q 2CE , , /Q 3CE , ,7 * J2/Q 3DB , , J2/Q 3DC , , /Q 3DE ,7 T2ED 055/QCLN 2FD , ,6 T7FC 055/QCL7C 7FC , , ,55 * J2/Q 2FB , , , J2/QCL7C 7FB , ,5 * BJ2/QCL7C 5FD , , , J2 2FD * SKF Explorer bearing 828

34 C a C b D a d a d b D b r a r b Dimensions Abutment and fillet dimensions Calculation factors d d 1 B C r 1,2 r 3,4 a d a d b D a D a D b C a C b r a r b e Y Y 0 ~ min. min. max. min. min. max. min. min. min. max. max. 7.1 mm mm ,3 1, , ,3 1,5 0,4 1,5 0, , , , ,43 1,4 0,8 65, , , ,43 1,4 0,8 65, ,31 1,9 1,1 65,1 21,5 17 3,6 1, ,5 3,4 1,2 0,3 2 1, ,5 1, ,5 1,5 0,4 1,5 0, ,5 1, ,5 1,5 1,5 0,43 1,4 0,8 68, ,5 1, ,5 1,5 1,5 0,43 1,4 0,8 68, , ,5 0,8 0,33 1,8 1 68, , ,5 2,5 0,33 1,8 1 70, ,5 1,5 1, ,5 1,5 1,5 0,4 1,5 0,8 73, ,5 2, ,5 2,5 0,35 1,7 0,9 81, ,5 2,5 0,88 0,68 0,4 77, , ,5 2 0,35 1,7 0,9 81, , ,5 2 0,83 0,72 0,4 83, , ,5 2 0,54 1,1 0,6 77, , ,5 2 0,35 1,7 0, , ,5 1,5 1, ,5 1,5 1,5 0,4 1,5 0,8 73, ,5 1, ,5 1,5 0,31 1,9 1,1 75, ,5 1, ,5 1,5 0,37 1,6 0,9 74, , ,5 2 1,5 0,4 1,5 0,8 75, , ,5 2 1,5 0,4 1,5 0,8 78, , ,5 0,4 1,5 0,8 80, ,5 2, ,5 2,5 0,35 1,7 0,9 89, , ,5 2,5 2,5 0,88 0,68 0, , ,5 2,5 2 0,35 1,7 0,9 88, , ,5 2,5 2 0,83 0,72 0,4 90, , ,5 2,5 2 0,54 1,1 0,6 84, , ,5 2,5 2 0,35 1,7 0,9 829