Cutting gear teeth: Cutting straight teeth is definitely comparatively easier than cutting helical teeth. Gear milling or equipment hobbing can be used to cut tooth of spur and helical gears. In milling, only two simultaneous motions are wanted to cut tooth of spur gears; however, three simultaneous motions are necessary for cutting the teeth of helical gear.
Effect load, vibration and noise: 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 optimum permissible speed of operation. On the contrary, gradual get in touch with between mating teeth outcomes a gradual load on one’s teeth and lower vibration and sound. Thus helical gears can be employed at higher velocity without much problem.
Contact scenario between mating teeth: Spur gears have straight teeth parallel to equipment axis. Two mating gears are also installed in parallel shafts. Thus the teeth of two mating spur gears come in sudden contact and the get in touch with is always a type of length equals to teeth encounter width. On the other hand, 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 begins with a point and becomes a line and then gradually disengages as a spot. So contact length does not remain constant.
Orientation of driver and driven shafts: One basic advantage of equipment drive over other mechanical drives (like belt or chain drive) is its probability to use for nonparallel shafts. However, several types of gear are ideal for varying orientations of driver and powered shafts. Both spur gear and helical gears are overwhelmingly used for parallel shafts; whereas, bevel gears can be used for intersecting shafts and worm equipment can be used for perpendicular non-intersecting shafts. There exists a particular type of helical equipment, called crossed helical equipment, which can be useful for transmitting power between perpendicular shafts. This is pretty similar to worm gear; however, crossed helical gear cannot offer high velocity decrease. Typically, it is suitable for 1:1 to at least one 1:2 acceleration ratio (in comparison with 1:15 to at least one 1:100 in worm gear). Its application can be limited due to many limitations.