Manufacturing and designing cost of helical gears will be more as compared to spur gear designing and manufacturing cost.Power loss in case of helical gear train operation will be more as compared to spur gear train operation.First of all, what is the important thing is to find the appropriate coordinate system of the tooth profile. The relation of can be deduced by the involute function: where is the module of gear and is the number of teeth of gear. One pair of mating helical gear will have less efficiency as compared to efficiency of mating spur gears of similar size. Involute function is very important in the gear design.Therefore helical gear requires good quality of lubrication. There will be sliding movement between mating gear teeth in case of helical gear and heat generation will be more as compared to spur gear application.
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When a pair of helical gear meshes with each other, there will be creation of axial thrust load on gear due to helix angle of gear teeth and therefore gearbox designer has to select such bearings those are able to absorb and support this axial thrust load.There will be less wear and tear in case of helical gear during operation as compared to wear and tear in case spur gears operation as if we consider helical gears operation, load will be distributed between several teeth at any time and that is why there will be less wear and tear in operation of helical gears.Helical gears will have more capability to transmit load between two parallel shafts as compared to similar module and equivalent width of spur gears.The general range of application is: Module m 1.
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