What Causes Wheel Lock-Up?
1 Answers
Wheel lock-up refers to the sudden locking of wheels when braking, causing the vehicle to lose steering capability. This typically occurs in vehicles without ABS (Anti-lock Braking System) and is primarily caused by excessive braking force applied by the brake pads to the disc or drum. Phenomenon of wheel lock-up: In cars without ABS, if the brake pedal is pressed hard while driving, the wheel speed rapidly decreases. When the braking force exceeds the friction between the wheels and the road, the wheels lock up. Fully locked wheels increase the friction between the tires and the road, potentially leading to skidding and loss of directional control under high inertia. If the front wheels lock up, the driver loses control over the vehicle's direction. If the rear wheels lock up, skidding is more likely to occur. Solutions to wheel lock-up: ABS is designed to prevent wheel lock-up during braking. In ABS-equipped vehicles, when encountering an emergency, the system continuously monitors the speed of each wheel through speed sensors installed on the wheels or drive shafts. It compares this data with the ideal slip ratio and adjusts the braking pressure accordingly. The controller commands the regulator to reduce the hydraulic pressure in the wheel's brake cylinder, decreasing the braking torque. After a certain period, the original hydraulic pressure is restored. This cycle repeats continuously, ensuring the wheels remain rotating while maintaining maximum braking torque. Thus, ABS keeps the wheels in a slightly slipping rolling state during braking, achieving optimal braking performance.
