Final answer:
The four mechanical types of limited slip units used in drive axles are the Cone Type, Clutch Type, Helical Gear Type (Torsen), and Viscous Coupling Type, each employing a different mechanism to improve traction by distributing power effectively.
Step-by-step explanation:
There are four mechanical types of limited slip units used in drive axles. These are:
- Cone Type: Utilizes cone-shaped friction surfaces interfaced with the differential casing. When torque is applied, the cones press against the casing, creating friction that limits differential action.
- Clutch Type: Makes use of clutch packs positioned between the differential carrier and the side gears. Under torque, these clutches lock up to provide traction to both wheels.
- Helical Gear Type (Torsen): Employs helical gears and worm gears, which bind under differential speeds, thereby limiting the amount of slip between wheels.
- Viscous Coupling Type: Uses a viscous fluid and multiple plates within a sealed housing. Differential wheel speeds cause the fluid to heat and thicken, which in turn applies a shearing force to slow the faster-spinning wheel.
All these types of limited slip units are designed to improve traction by distributing power to the wheel with the most grip while still allowing for a necessary degree of wheel speed differentiation.