Cutting gear teeth: Slicing straight teeth is usually comparatively easier than slicing helical teeth. Equipment milling or equipment hobbing can be utilized to cut teeth of spur and helical gears. In milling, only two simultaneous motions are wanted to cut the teeth of spur gears; however, three simultaneous motions are required for cutting teeth of helical gear.
Impact load, vibration and sound: Since teeth of two mating spur gears comes in sudden contact, therefore they encounter a shock or effect load. This also produces significant vibration and noise, which sometimes impose limit on maximum permissible speed of operation. On the other hand, gradual contact between mating teeth outcomes a gradual load on one’s teeth and lower vibration and sound. Thus helical gears may be employed at higher speed 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 teeth of two mating spur gears come in sudden get in touch with and the get in touch with is always a line of size equals to teeth encounter width. On the other hand, helical gears possess helical teeth and 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 range and then gradually disengages as a point. So contact length will 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 its likelihood to use for nonparallel shafts. However, various kinds gear are ideal for various orientations of driver and powered shafts. Both spur gear and helical gears are overwhelmingly utilized for parallel shafts; whereas, bevel gears can be used for intersecting shafts and worm gear can be used for perpendicular non-intersecting shafts. There is a particular kind of helical gear, called crossed helical gear, which can be employed for transmitting power between perpendicular shafts. This is fairly similar to worm gear; however, crossed Kovèti pou hélicoïdal cannot provide high velocity decrease. Typically, it is suitable for 1:1 to 1 1:2 rate ratio (as compared to 1:15 to at least one 1:100 in worm gear). Its application can be limited due to many limitations.