29-08-2017, 09:07 AM
Failure of gear teeth due to fatigue is a common phenomenon. A small reduction in the pulling effort of the root results in an increase in the fatigue life of a gear. For many years the design of the gear has been improved using different materials, hardening gear surfaces with heat treatment and shot blasting to improve the surface finish. Some additional efforts have been made to improve strength and durability by altering the geometry of root fillet curves, altering pressure angles, etc. A finite element model with a three-tooth segment is considered for analysis and the stress relief characteristics of various diameters are introduced into gear teeth. The analysis revealed that the circular feature of stress relief at specific locations is beneficial.
Rectilinear gears are used to transmit the movement and power from one axis to another, especially between two parallel axes and are also used to vary the speed and torque. The cost of replacing the straight gear is very high and also the system downtime is one of the effect in which these gears are part of the system. When the gear is loaded, the high stresses developed at the root of the teeth, these high stresses increase the probabilities of fatigue failure at the root of the teeth of the straight gear. The goal of this research is to reduce the stress of the root steak to increase the fatigue life of the straight gear. This article presents techniques for reducing root stress in the straight gear by introducing the stress relief features in the stress zone. Three straight gear teeth are taken for study. Using the maximum Lewis equation, the main stress is calculated by applying the load to the tip of the tooth. In the same way the straight gear in the ANSYS software for the maximum main voltage is analyzed. In comparison, it is found that both results are above 900 closed. The maximum principal tension in the spherical gear root fillet calculated in ANSYS is 10% less than the theoretical result. When considering the maximum main voltage in ANSYS as a base, an additional work is done in ANSYS. The circular tension relief features are used in various locations on straight gears to reduce maximum main tension. Main stress reduction increases the fatigue life of the straight gear.
Rectilinear gears are used to transmit the movement and power from one axis to another, especially between two parallel axes and are also used to vary the speed and torque. The cost of replacing the straight gear is very high and also the system downtime is one of the effect in which these gears are part of the system. When the gear is loaded, the high stresses developed at the root of the teeth, these high stresses increase the probabilities of fatigue failure at the root of the teeth of the straight gear. The goal of this research is to reduce the stress of the root steak to increase the fatigue life of the straight gear. This article presents techniques for reducing root stress in the straight gear by introducing the stress relief features in the stress zone. Three straight gear teeth are taken for study. Using the maximum Lewis equation, the main stress is calculated by applying the load to the tip of the tooth. In the same way the straight gear in the ANSYS software for the maximum main voltage is analyzed. In comparison, it is found that both results are above 900 closed. The maximum principal tension in the spherical gear root fillet calculated in ANSYS is 10% less than the theoretical result. When considering the maximum main voltage in ANSYS as a base, an additional work is done in ANSYS. The circular tension relief features are used in various locations on straight gears to reduce maximum main tension. Main stress reduction increases the fatigue life of the straight gear.