Roller Chain - Tsubaki

Drive Chain SelectionExample based on the slow speed selectionMachine: Conveyor driveChain load: 3754 lbs.Motor: 15 HPReducer ratio : 30High speed shaft : 50 r/min, shaft diameter 2 1/2”Low speed shaft : 20 r/min, shaft diameter 3 7/8”Distance b/w shafts : 60”Starting frequency : 4 times/dayType of shock: Some shock involvedSprocket 15T(PCD: 7.2”)60"(center distance)2.6"Sprocket 38T(PCD: 18.1”)Drive ChainReducer ratio(i = 30)3.7"Drive Roller Chain(RS120)Calculate the Roller Chain speed V.PN’nV = = 10001.5 × 15 × 5012= 93.75 ft/min < 160 ft/minThe calculated speed (93.75ft./min) is less than 160ft/min, so slow speed selection can be used.Imperial UnitsMetric UnitsF l = 3754 lbs.F l = 1700 (kgf)Procedure 1 :Service factor K s = 1.3 ……………… some shock (Table 2)Speed factor K v = 1.06 ……………… V = 28.6 m/min (90 ft./min) (Table 3)Sprocket teeth factor K c = 1.27 ……… N’ = 15T (Table 3)Procedure 2 : Calculate design chain tension F’ lF’ l = F l × K s × K v × K c= 3751 x 1.3 x 1.06 x 1.27= 6569 lbs.Procedure 2 : Calculate design chain tension F’ lF’ l = F l × K s × K v × K c= 1700 × 1.3 × 1.06 × 1.27= 2975 (kgf)Procedure 3 : Slow speed selection for RS Roller ChainRS120 can be used since the maximum allowable tension of 6830 lbs. (3100 kgf) is larger than the design chain tension 6569lbs. (2975 kgf). The driver sprocket is RS120-15T B-type (Max. shaft diameter 3 1/4” > Driver shaft diameter 2 1/2”, thereforeacceptable) provided it has hardened teeth. The driven sprocket is RS120-38T B-type, provided the bore diameter ismanufactured to meet the diameter of the driven shaft (3.7”).Procedure 4 : Number of chain links( ) 2N – N'38 – 15N + N' 6.28 38 + 15 6.28L = + 2C + = + 2 × 40+2C240= 106.8 links → 107 links Distance between shafts = 60”Procedure 5 : Lubrication method is by drip or brush( ) 260C = 1.5= 40A-99