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Calculating Service Life Series Coefficient of friction K BTCA and BTSA 1.2~107 Other series 5~106 Impact fluctuating loads Load factor fw None 1.0 Yes 2.0 to 3.0 CAUTION All Oiles slide shifter series employ Oiles bearings and work without the need for lubrication, in principle. If they are lubricated, foreign matter may be removed and the durability is improved further. The service life of the Oiles slide shifters depends on the speed, environmental conditions, etc. Take the condition shown below into consideration and find the service life using the service life calculation formula. It will be the basis of design. Service life calculation formula (N: Number of durability test cycles) N=a~K~@1@~@@ ~ 2‚r Wa Wi/n fc fw~fv~fe~f. œK = coefficient of friction @The slide shifters use various types of Oiles bearings. The coefficient of friction is set according to their performances and using conditions. œa = allowable wear amount [mm] @Determine the amount of wear allowed to ensure the accuracy in the machine in use. @* BTCA and BTSA: 0.15 mm or less œfw = load factor @This factor is used for compensation of the load conditions, since it is difficult to grasp the actual vibrations, impacts, etc. produced in machines. Running distance and lubrication Lubrication factor f. No lubrication 1.0 to 1.5 Lubrication every 10 km 0.3 to 0.5 Lubrication every 1 km 0.2 to 0.3 œfl = lubrication factor @Lubrication enhances the effect in high-speed operation or foreign matter need to be removed. Number of tables per axis Contact factor fc One 1.0 Two 0.75 to 0.85 Three 0.65 to 0.75 Four 0.6 to 0.65 œfv = velocity factor @This factor is used for compensation of the speed conditions. Velocity condition Velocity factor fv 0.0017 or less 0.25 to 0.3 0.0017 to 0.05 0.3 to 1.0 0.05 to 0.5 1.0 to 2.0 0.5 to 1 2.0 to 4.0 (Unit: m/sec.) œfe = environmental factor @This factor is used for compensation of the ambient temperature and influences of foreign matter. Ambient temperature Foreign matter Environmental factor fe 60‹C or less 60 to 100‹C None 1.0 to 2.0 Yes 3.0 to 6.0 None 3.0 to 6.0 Yes 6.0 to 12.0 ¦Lubrication is needed if the temperature is 100‹C or more. œS = stroke [m] œWa = allowable load [N {kgf}] @See the Parts List. œWi = load [N {kgf}] @Select the severest one (i.e., value nearest the allowable load) at the load applied to each table calculated with the load calculating formula. œn = number of tables @Use the table with the severest condition when several shifters are used. In such a case, n = 1. œfc = contact factor @When several shift tables are used, it is difficult to obtain uniform load distribution due to influences of the installation surface accuracy. This factor is determined by taking the contact conditions of the shift tables into consideration. ¦Use the BTCA and BTSA in the self-lubricating conditions. Technical Information of Slide Shifters 326 Selection Guide Product Information Plastic Bearing Multi-layer Bearing Metallic Bearing Air Bearings Technical Slide Shifter Information Corporate Profi le