Advanced Development of Self-Controlled Torque Sensitive Limited-Slip Differential by Means of Helical Gears

This paper compares and contrasts several types of torque-sensitive limited slip differential designs while focusing on the self-controlled helical gear differential. Cone-and plate-type locking differentials in common use today offer a low production cost but tend to change locking characteristics as they wear and influence vehicle handling and braking. Current worm gear type limited slip differentials present a disadvantage in that they have a limited range of available locking ratios as a function of cost and also present long-term durability issues. Thus, attention has turned in recent years to the self-controlled helical gear approach. This method offers a wide range of locking ratios thus making it possible to tune the performance of the differential to match virtually any vehicle. Applications involving use of this design as a rear wheel differential and as a center differential are described. Uneven distribution of torque is often desirable in a center differential and the design principles involved in achieving this effect are explained. Finally, a test rig was developed to measure the locking effect and service life of the helical gear differential and it showed that these devices maintain consistent performance over their service life, as compared to current torque sensitive devices.