PolyChain® GT Timing Belts - Walther Flender

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Walther Flender Gruppe PolyChain ® GT Timing Belts PAGE 26 Calculation method To select a suitable PolyChain® GT2 timing belt drive system, you need the following data: 1. Power output and type of drive machine and driven machine 2. Operation time 3. Speed of drive machine and driven machine 4. Centre distance of axes of the drive system Step 1: Determine the calculated power output A. To determine the calculated power output, firs you have to define the load factor S 1 of the drive from the table on page 25. B. Multiply this load factor times the input power. The result is the calculated power output required for defining the belt drive. P B = P N · S 1 Step 2: Select the timing belt pitch A. Enter the calculated power output in the “Selection diagram for belt pitch” (page 5) on the horizontal axis. Use the speed of the faster shaft (or of the small timing belt pulley) for the vertical axis. B. The timing belt belt pitch for further calculations can be found at the point where the two factors intersect. If the point of intersection is near the separation between 8 mm and 14 mm pitch, it is recommended to calculate the drive system for both pitches and to use the drive system that is best suited for your application. Step 3: Select the timing belt width For all transmission and reduction drive systems A. The power output tables on pages 17 and 20 contain the values for the smallest standard belt width. A different width factor has to be used for larger belt widths. The column on the left side of the power output table contains the speed of the small timing belt pulley; the line above the table contains the number of teeth of the timing belt pulley and its pitch diameter. The power output of the timing belt can be found at the point where the pulley speed and the number of pulley teeth intersect. B. Select a belt width and determine the corresponding power output. Multiply this power output value times the timing belt length correction factor S 6 , which can be found in the table under the power output table* to determine the corrected power output. P KORR = P TAB, S.17ff. · S 6 · S 7 * Factors S 6 and S 7 are explained on pages 19 and 22. If the corrected power output is equal to or greater than the calculated power output, this belt width can be used. If not, repeat this step with the next larger timing belt width. If the largest belt width does not produce satisfactory results, you should use a larger timing belt pulley or, if possible, a larger pitch. P KORR > P B · S 2 Note: Depending on the degree of acceleration and braking torque and the frequency of reversal of motion, the timing belt pulley diameter should be as large as possible with a minimum of 12 meshing teeth. If the number of meshing teeth is less than 6, this has to be compensated for with the correction factor S 2 in the drive calculation. Tooth mesh factor S 2 Number of meshing teeth 5 4 3 2 S2 1.25 1.66 2.5 5.0 Number of meshing teeth Ze on the small pulley: Ze = Z k [ 3 – d wg – d wk ] 6 A C. If the calculation results in several possible combinations of timing belt pulleys, you should observe the following principles: a. A larger timing belt pulley diameter requires a smaller timing belt width. b. The belt width should not be greater than the diameter of the smallest timing belt pulley. c. Large timing belt pulley diameters reduce wear on the bearings and shaft. Step 4: Installation and belt tension Due to the low stretching tendency of the tensile member, PolyChain® GT2 belts generally require no re-tightening. Adjustments must be made during installation of the belts to compensate for production tolerances and to set a specified initial tension. The recommended radial settings of the centre distance of axes are listed on page 14. Step 5: Calculation of initial belt tension The initial required tension is calculated based on the equations on page 13. Step 6: Select the drive components Based on the calculated drive system data and geometries, you can select a suitable drive component combination from the standard line of pulleys. In special cases, it may be necessary to manufacture custom pulleys according to your drawing specifications.
Walther Flender Gruppe PolyChain ® GT Timing Belts PAGE 27 Sample calculation Drive data Drive: Three-phase motor, high starting torque P = 5 kW at n 1 = 1750 min-1 Duty cycle 6 hours daily Step-up ratio Step 1: Determine the calculated power output P B Output: Woodworking machine, n 2 = 2150 min-1 Centre distance of axes ca. 430 mm. Calculation steps Results A. Type of drive machine: You will find the drive motor used in the third class in the table on page 15. B. Load factor from table (woodworking machines): 1,6. C. Calculated power output = Load factor x drive power P B = S 1 x P N Step 2: Select the pitch From the “Selection diagram for belt pitch” on page 5 you see that: at 8 kW and 2150 min -1 a pitch of 8 mm is recommended. Select the combination of timing belt pulleys, timing belt length, Calculate the centre distance of axes: 1. Calculation of the transmission ratio i = 2150 = 1.23 1750 2. Select the number of pulley teeth based on the required transmission i e.g. z 1 = 34; z 2 = 28 i = 1.214 3. Select the timing belt length analogous to the existing pitch lengths of the pitch 8M e.g. I w = 1120 mm 4. Calculate the centre distance of axes with the corresponding factors (Separate formula collection, to be provided on request) A = 435.93 mm Step 3: Select the belt width In the power output table on page 17, for a timing belt pulley with 28 teeth at a speed of 2,150 min -1 a power output of P TAB, z 1 = P TAB · S 6 · S 7 = 14,8 kW is specified for a belt width of 21 mm. This power output is higher than the calculated power output P B = 8 kW, multiplied by the tooth mesh factor (S 2 = 1) Step 4: Installation and mounting data According to the tables on page 14, the minimum travel of a shaft to the initial belt tension is –2.8 mm/+0.8 mm. Step 5: Calculation of initial belt tension Use the equation on page 15. Load factor S 1 = 1.6 Calculated power output = 1.6 x 5 = 8 kW Belt pitch = 8 mm i = 1.23 selected: z 1 8M - 34 S z 2 8M - 28 S selected: Timing belt length = 1120 mm Centre distance of axes: 435.93 mm Belt width b = 21 mm Minimum travel to belt tension: –2.8 mm / +0.8 mm Deflection force = 12.6 N Deflection = 4.4 mm
Page 1 and 2: THE POWER OF [E]MOTION PolyChain®
Page 3 and 4: Walther Flender Gruppe PolyChain ®
Page 7 and 8: Walther Flender Gruppe PolyChain Pa
Page 25: Walther Flender Gruppe PolyChain ®
Page 33 and 34: Clamping sets
Page 35 and 36: Walther Flender Gruppe Clamping set
Page 47 and 48: Notizen

PolyChain® GT Timing Belts - Walther Flender

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