Design and Analysis of an Automotive Differential by Changing the Final Reduction Ratio

Abstract

Differential gear system is called the system used due to the different amounts of distance traveled by the wheels of the vehicles while cornering. Differential is designed according to the road handling performance and some features of the vehicles. Differential types differ due to needs. In fact, they all have the same function. In the differential gear system, hypoid bevel gears are preferred instead of spur gears. The differential mechanism is a gear system that transmits the movement of the drive shaft to the wheel, reduces its speed and increases its torque, and ensures the ease of the first movement in the vehicle. In the hypoid gear type, since the gear axes are perpendicular to each other, the center of gravity of the vehicle is moved closer to the ground, improving the handling of the vehicle. The use of any of the bevel gear groups of the ring gear and pinion gear is preferred because it reduces vibration and noise caused by friction. Commonly available automobile differentials have a maximum reduction ratio of 6. This is because designing an automotive differential with a reduction ratio greater than 6 results in a bulky design that is impossible to position with the limited space available. Also, increasing the size of the differential can lead to excessive unwanted weight. Most land vehicles have differentials with reductions of 3 or 4. Commercially speaking, it is almost impossible to find a differential with a reduction greater than 6. Most manufacturers introduce an additional single-speed gearbox, but this would complicate the design and increase service costs. The aim of this study is to design and analyze a differential with different reduction ratios. The article includes a force-based analysis performed in Adams and Ansys Simulation, as well as all calculations to prove the success of the design. In this study, changes were made in the cycle ratio by keeping the ring gear constant and taking into account the changes in the number of pinion gears. As a result of mathematical calculations and analysis, a decrease was observed in the normal module value as the cycle ratio increased. A quieter working environment was provided by using hypoid gears instead of spur gears in the design. As the distance between the axes increased, the mirror helix angle decreased and the efficiency decreased. As a result of the analyses, it was possible to intervene earlier in problems that may be observed during and after the production process.