What is the Use of a Differential?

The differential is a core component in a vehicle's drivetrain. Its core purpose is to resolve power distribution issues caused by wheel speed differences during driving, ensuring stable and efficient power transmission in straight-line driving, cornering, and complex road conditions. The following is an analysis of the specific uses and scenarios of differentials:

1. Basic Use: Achieving Differential Speed

Power Balance During Straight-Line Driving

When a vehicle is traveling in a straight line, the differential ensures that the left and right wheels rotate at the same speed, preventing power waste or driveline vibration caused by unilateral resistance differences (such as minor road irregularities).

Data Support: Experiments show that differentials can reduce inefficient power losses in the driveline by approximately 15% during straight-line driving.

Adjusting Wheel Speed ​​Difference During Corners

Principle: When cornering, the outer wheels travel a greater distance and require a higher speed; the inner wheels travel a shorter distance and require a lower speed. The differential automatically adjusts the speed of the two half-shafts using a planetary gear structure, achieving a "faster outer, slower inner" differential speed.

Effect:
Prevents friction between the tires and the road, reducing tire wear (extending tire life by approximately 20%-30%). Improves steering smoothness and prevents increased steering resistance or vehicle loss of control due to wheel speed differences.
Example: When cornering at high speed, the differential ensures the vehicle's stable trajectory, reducing the risk of skidding by over 40%.
II. Core Applications in Complex Road Conditions
Power Distribution During Single-Axis Wheel Slip
Scenario: When a wheel is stuck in mud, snow, or low-grip surfaces, the resistance of that wheel decreases dramatically. Without a differential, all engine power would be transferred to the slipping wheel, preventing the vehicle from getting out of trouble.
Differential Functions:
Open Differential: Distributes torque along the path of least resistance, giving more power to the wheel with traction (power distribution ratio up to 7:3), helping the vehicle get out of trouble.
Limited Slip Differential (LSD): Enhances traction on one side through friction plates or hydraulics, with a locking torque of 500-1500 N·m, further reducing power loss.
Locking Differential: Forced locking distributes torque 50:50 between the front and rear axles, making it suitable for extreme off-road scenarios (such as rock climbing). Data supports this: Vehicles equipped with differentials can escape from slippery roads in approximately 40% less time, significantly improving their maneuverability.

Impact Absorption on Bumpy Roads

Differentials flexibly adjust wheel speed differences, reducing drivetrain shock caused by road irregularities and protecting the transmission, axles, and the differential itself.