387 Table Material Steel Stainless Aluminium UHMW Teflon Friction coefficient: μ 0.65 0.68 0.42 0.31 0.21 ~5 5~8 8~12 12~16 16~24 1.0 1.1 1.2 1.3 1.4 ~1500 1501~3000 3001~4500 4501~ 0.3 0.2 0.1 0.0 ~60 61~90 91~120 0.0 0.1 0.2 Belt Type L H S5M S8M T5 T10 AT5 AT10 Pitch (mm) 9.525 12.7 5 8 5 10 5 10 Min. No. of Pully Teeth 14 14 14 24 12 14 20 14 Pully Diameter (mm) 42.45 56.60 22.28 61.12 19.10 44.56 31.83 44.56 Table 1. Typical Friction Coefficient of Belt versus Table Table 2. K1 Correction Factors for Daily Operation Hours Unit: hour Table 3. K2 Belt Length Correction Factors Unit : mm Table 4. K3 Belt Speed Correction Factors Unit : m/min Table 6. Number of Minimum Allowable Number of Teeth for Pulleys Belt Type Belt width (mm) 10 15 20 25 30 40 50 S5M 120 180 − 300 − − − S8M − 235 − 392 471 627 − T5 58 87 116 145 − − − T10 − 180 240 300 360 481 601 AT5 74 110 − − − − − AT10 − 234 312 391 − − − Table 5. Allowable Tension of Joint Belts Belt Type Belt Nominal Width 050 075 100 150 200 L 92 138 184 276 − H − 163 216 324 432 Unit : N Unit : N Belt Type Inner Adjustment Allowance L More than 10mm H More than 15mm S5M More than 10mm S8M More than 15mm T5 More than 5mm T10 More than 10mm AT5 More than 10mm AT10 More than 15mm Table 7-a: Inner Adjustment Allowance (Attachment Allowance) Distance between shafts (mm) Outer Adjustment Allowance ~ 500 More than 5mm 501~1000 More than 10mm 1001~1500 More than 15mm 1501~2000 More than 20mm 2001~2500 More than 25mm 2501~ More than 1% of center distance Table 7-b: Outer Adjustment Allowance (Tension Allowance) Belt Type Belt width (mm) 10 15 20 25 30 40 50 S5M 60 90 − 150 − − − S8M − 117 − 196 235 313 − T5 29 43 58 72 − − − T10 − 90 120 150 180 240 300 AT5 37 55 − − − − − AT10 117 156 195 − − − − Table 8. Installation Tension for Joint Belts Belt Type Belt Nominal Width 050 075 100 150 200 L 46 69 92 138 − H − 81 108 162 216 Unit : N Unit : N QConveyer belts selection procedure The following steps for selection are provided by assuming that sizes of head pulley and tail pulley are same. (Follow the steps 1 -3 even when sizes of head pulley and tail pulley are different) Use a head pulley as a driving pulley. For belt installation and tension control, make the structure of the driven side to be adjustable for alignment and center distance with set screws. *Head Pulley: The front of the pulley against traveling direction Tail Pulley: The rear end of the pulley against traveling direction [Step 1] Calculate effective tension (Te). [Step 4] Determine belt length (no. of teeth) and center distance. (1) Obtain approximate belt length from tentative center dimension (C') and approximate pulley diameter (Dp'). Lp’ = 2·C’ + π· Dp’ Lp' (mm) Approx. belt length C' (mm) Tentative center dimension Dp' (mm) Approx. pully diameter (2) Determine the number of teeth required from the approximate belt length (Lp') and pitch (P). Round down the obtained number of teeth (N) to the nearest whole number. N= Lp’ /P N No. of belt teeth p (mm) Pitch *Check the minimum teeth of belt which is available. (3) Obtain the proper belt length from the number of teeth (N) and pitch (P). Lp= P·N Lp (mm) Belt length (4) Determine proper center distance with the following formula: C= P · (N−Dz)/2 C (mm) Center Distance Dz No. of teeth of pulley [Step 5] Confirm the ajustment margin for the center distance is larger than figures in Table7-a and 7-b. Te= 9.8(μ·G+G·H/C) Te (N) Effective tension G (Kg) Net weight of load placed on the belt surface μ Friction coefficient of belt vs. table (Table 1) H (mm) Lift C (mm) Tentative center dimension (conveyor length) Head pulley (Driving Pulley) Tail pulley H C Traveling Direction [Step 2] Calculate design tension (Td). Td=K·Te Td (N) Design Tension K Overload Coefficient Te (N) Effective Tension K=K1+K2+K3 K1 Correction factors for daily operation hours K2 Belt length correction coefficient K3 Belt speed correction coefficient [Step 3] Select belt type, belt width and pulley dimension. (1) Select from Table 5 a belt type and a width which have a greater allowable tension than the designed tension. (2) Select a pulley with a larger number of teeth than the minimum allowable number in Table 6 for both of driving and driven pulley. Center Distance Inner Adjustment Allowance Outer Adjustment Allowance [Step 6] Install timing belt. Install the belt with the installation tension in Table 8. Axis weight at this time is twice the installation tension. Fs= 2· Ti Fs (N) Shaft load Ti (N) Fixing Tension (Table 8) Belt Type Material Belt width (mm) 6 10152025304050 S3M Polyurethane 127 − − − − − − − S5M Rubber − 310 490 − − − − − Polyurethane 215 323 539 S8M Rubber − − − − 950 − − − Polyurethane 647 1176 1412 1882 T5 Polyurethane − 112 166 225 284 − − − T10 Polyurethane − − 299 397 529 627 862 1064 AT5 Polyurethane −147221− − − − − AT10 Polyurethane − − 469625781 − − − Belt Type Material Belt Nominal Width (mm) 025 037 050 075 100 150 200 XL Rubber − 45 70 − − − − Polyurethane 66 102 142 L Rubber − − 95 165 − − − Polyurethane 259 387 519 H Rubber − − − − 600 − − Polyurethane 397 529 799 1093 Reference: Table on Open-end belts Allowable Tension Unit : N Unit : N &When using belts for other purpose than conveyance (e.g. transmission), for polyurethane belt S3M; design with 1/2 of the allowable tension in the table; for XL, L, H, S5M, S8M, T5 and T10, design with approx. 2/3 of the allowable tension in the table. Timing Belt Selection of ConveyorTiming Belts
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