Some studies on quality and strength of asymmetric high contact ratio Gear machined using wcedm

Abstract

Gear is defined as a machine element used to transmit motion and power between rotating parts through the progressive engagement of projection called teeth. The different types of gears such as spur, bevel, helical, hypoid, and worm gear are used depending upon the shaft layout and power requirements. The standard spur gear drive is most commonly used due to the relative advantage it has compared to other gears. The spur gear should possess enough bending and contact strengths to transmit power. These strengths depend on the material and various gear geometrical parameters such as pressure angle, addendum, face width, etc. Due to the increasing demand for high load carrying capacity with lightweight gears researchers are interested to develop nonstandard gears. In the recent period, nonstandard gear such as asymmetric gear and high contact ratio have been highly researched. Since the workload on the load side profile is significantly higher and is applied for longer periods than the opposite non-drive side profile, the non-drive side profile is changed to get the maximum power transmission. Hence the profile is asymmetric about the tooth centerline. The Normal Contact Ratio (NCR) gears with standard gear proportions are widely used in power transmission, in which contact ratio is maintained below two, hence the maximum number of teeth pairs that share the load in a mesh cycle is two. Whereas in High Contact Ratio (HCR) gears the standard gear proportions are modified such a way that the contact ratio will be more than two; hence the maximum number of pairs in contact in a mesh cycle will be three. Hence it will transmit more power than the NCR gear of the same module due to the distribution of load to the two or more pairs. newline newline newline