Gear Tooth Profile

Gear Tooth Profile:

One of the fundamental s of gear design is the profile of the gear tooth. Gears generally have an involute curve tooth profile. There are other types of gear profiles, but they are mainly utilized in specialty applications such as cycloidal gears in clocks and watches.

This involute curve helps the gears transmit power smoothly during the rolling action. The curve is produced by wrapping a string around a cylinder, the base circle, and as it is unwrapped from this cylinder traces the involute curve. The base circle of the involute curve is also important because it helps to determine the pressure angle of the gear, another fundamental of gear design.

The contact point of the gear and pinion goes along the involute curves of the gears. The involute gear tooth profile also helps with smooth rotation even with variations in the center distances between the gear and the pinion. The tangent line of the base circle of the gear and the base circle of the pinion form the line of action for the gear set. The tooth thickness, diametral pitch and pressure angle all go into determining the gear tooth profile. These factors are determined by the desired contact ratio between mating parts of the gear. The gear tooth profile also varies by the number of teeth on the gear such that the larger the amount of teeth the straighter the profile of the gear eventually forming what is called a rack gear. An advantage to making a rack form is strength obtained through the rack form.

Many gear manufacturing firms also have the ability to determine the gear profile from the geometry of the hobs that is used to generate the teeth on a gear. This method is used in order to reverse engineer gears that may need to be replaced by the original part’s manufacture is no longer capable of manufacturing that part. While this method is able to generate the profile of the gear, the firm would still need some supplementary dimensions in order to accurately reverse engineer said part.

Marples Gears specializes in high precision fine pitch gear manufacture up to Q13 quality standard on our gear products that we custom manufacture in house. At Marples Gears, we also use software in order to analysis the gear tooth profile of your part. While we are not certified to design gears through AS9100-D, but we can consult on the best method of manufacturing of your gears. Marples Gears also has the ability to reverse engineer as gear through the method discuss above and through the analysis of the original gear. For a custom engineer reviewed quote email info@marplesgearsinc.com or visit our custom quote page under the contact us tab above.