Cutting gear teeth: Reducing straight teeth is certainly comparatively easier than cutting helical teeth. Equipment milling or gear hobbing can be utilized to cut tooth of spur and helical gears. In milling, just two simultaneous motions are wanted to cut teeth of spur gears; however, three simultaneous motions are required for cutting the teeth of helical gear.
Impact load, vibration and sound: Since teeth of two mating spur gears will come in sudden contact, therefore they experience a shock or effect load. This also generates significant vibration and noise, which occasionally impose limit on maximum permissible speed of procedure. On the other hand, gradual contact between mating teeth results a gradual load on one’s teeth and lower vibration and noise. Thus helical gears can be employed at higher acceleration without much problem.
Contact scenario between mating teeth: Spur gears have straight teeth parallel to gear axis. Two mating gears are also installed in parallel shafts. Thus teeth of two mating spur gears can be found in sudden get in touch with and the contact is always a line of duration equals to teeth face width. On the contrary, helical gears possess helical teeth plus they are mounted on parallel shafts. So tooth of two mating helical gears can be found in gradual get in touch with. Their engagement starts with a spot and becomes a series and then gradually disengages as a spot. So contact length does not remain constant.
Orientation of driver and driven shafts: One fundamental advantage of gear drive over other mechanical drives (like belt or chain drive) is the likelihood to use for nonparallel shafts. However, various kinds gear are suitable for different orientations of driver and driven shafts. Both spur equipment and helical gears are overwhelmingly utilized for parallel shafts; whereas, bevel gears can be utilized for intersecting shafts and worm gear can be utilized for perpendicular nonintersecting shafts. There is a particular kind of helical equipment, called crossed helical equipment, which can be employed for transmitting power between perpendicular shafts. This is very similar to worm equipment; however, crossed helical gear cannot provide high velocity decrease. Typically, it is suitable for 1:1 to at least one 1:2 velocity ratio (when compared with 1:15 to 1 1:100 in worm gear). Its application can be limited due to many limitations.