Be sure that shafts are parallel and pulleys are in alignment.Instrumentation for measuring belt tension is available.Ĭonsult the product section of this catalog. In such a case, the tension should be increased gradually, until satisfactory operation is attained.Ī good rule of thumb for installation tension is as shown in Figure 20, and the corresponding tensioning force is shown in Table 9, both shown in SECTION 10 BELT TENSIONING.įor widths other than shown, increase force proportionally to the belt width. When torque is unusually high, a loose belt may "jump teeth" on starting. Preloading (often the cause of premature failure) is not necessary. Consequently, a belt, when installed with a snug fit (that is, not too taut) assures longer life, less bearing wear and quieter operation. The positive grip of the belt eliminates the need for high initial tension. Timing belt installation should be a snug fit, neither too tight nor too loose.The following precautions should be taken when installing all timing belt drives: Plastic pulleys with metal inserts or metal hubs represent a good compromise. plastic) is a matter of price, desired precision, inertia, color, magnetic properties and, above all, personal preference based on experiences. The choice of the pulley material (metal vs.Therefore, take this into account when the size of the smallest pulley and the materials for the belt and tension member are selected. If the belt reinforcing fiber, i.e., tension member, as well as the belt material, have high tensile strength and no elongation, the belt will not be instrumental in absorbing the shock loads.
These drives are subjected to continuous and large accelerations and decelerations.
#Pulleys timing belts series
The maximum allowable operating speed for T series is 4000 feet per minute (20 m/s). For the HTD belts, a speed of 6500 feet per minute (33 m/s) is permitted, whereas for GT2 belts, the maximum permitted speed is 7500 feet per minute (38 m/s). Belt surface speed should not exceed 5500 feet per minute (28 m/s) for larger pitch belts and 10000 feet per minute (50 m/s) for minipitch belts.When the center distance between the shafts is 8 or more times the diameter of the smaller pulley, or when the drive is operating on vertical shafts, both pulleys should be flanged. Because of a slight side thrust of synchronous belts in motion, at least one pulley in the drive must be flanged.The shear strength of a single tooth is only a fraction of the belt break strength. The number of teeth in mesh may be obtained by formula given in SECTION 24 TIMING BELT DRIVE SELECTION PROCEDURE. In order to deliver the rated horsepower, a belt must have six or more teeth in mesh with the grooves of the smaller pulley.Belts with Fibrex-glass fiber tension members should not be subjected to sharp bends or rough handling, since this could cause breakage of the fibers.The pulley diameter should never be smaller than the width of the belt.For other pitches, Table 8, should be used. For MXL pitch belts, the smallest recommended pulley will have 10 teeth.Belts should be rated at only 1/15th of their respective ultimate strength. Use of overload service factors is important. Drives should always be designed with ample reserve horsepower capacity.
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