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allows the two wheels to turn at different speeds. To reduce load, another spider gear is usually added on top meshing also with the two side gears and rotating in the opposite direction as the other spider gear. 2. Overall Gear Ratio: Driven/Driver = 15/10 = 3:2 or 1.5 Clockwise
Data/Exercises: Exercise 1Gear Specification/Part NumberGear Type Number of TeethPitch Diameter Diametral PitchGear Ratio for the Pair H2472Spur723”244:3H2496Spur964”24L112YBevel241.5”161:1L112YBevel241.5”16H1616RHelical161”162:1H1632LHelical322”16SpeedGear Pair 1Actual VelocityRatioTheoreticalVelocity RatioN1N241813.51.331.3364225.51.471.33854361.501.33SpeedGear Pair 2Actual VelocityRatioTheoreticalVelocity RatioN3N4412121163030118363611SpeedGear Pair 3Actual VelocityRatioTheoreticalVelocity RatioN5N64186226301522839182.22Overall Speed Ratio = 18:6 or 3:1Exercise 2Speed reducer driven by 1750-RPM electric motor directly connected by a coupling. Conveyor operates 3-10 hours per day and head shaft speed will be 36 RPM. Calculations indicate that 2000-inch pounds of torque needed at conveyor head shaft. 1.What is the service factor? a.1.252.What is the overall drive ratio? a.RPM Driver/RPM Driven = 1750/36 = 48.613.If belt drive used for secondary reduction, what is the ratio of worm gear reducer? Belt drive ratio is 1.215.
a.Drive Ratio/Belt Drive Ratio = 48.61/1.215 = 40 4.What is the actual torque at the reducer output shaft a.Torque/Belt Drive Ratio = 2000/1.215 = 1646.1 5.What is the normal torque? a.Actual x Service Torque = 1646.1 x 1.25 = 2057.636.What is the selected size of the reducer based on mechanical rating?