What is the working principle of an electronic parking brake?
2 Answers
Electronic parking brake works on the same principle as a mechanical handbrake, achieving parking by clamping friction between the brake shoes and brake drum or between the friction pads and brake disc. However, the control method replaces manual operation and mechanical linkage with electronic buttons and motor actions, hence the system is fully named the Electronically Controlled Mechanical Parking Brake System. Electronic parking brakes can be divided into two types: cable-pulled type and integrated caliper type. 1. Working principle of cable-type electronic parking brake: When the driver presses and holds the electronic parking brake switch, the emergency braking function is activated. When the service brake is functioning normally, the ESP system (Electronic Stability Program) controls the service brake to apply braking force to all four wheels. If the service brake fails, the electronic parking brake control unit evaluates signals from the wheel speed sensors of all four wheels, applies braking force to the rear wheels, and prevents them from locking up. In this case, the request to illuminate the brake lights is sent by the electronic parking brake control unit. 2. Working principle of caliper-type electronic parking brake: When the driver pulls the electronic parking brake button to engage the handbrake, the motor of the handbrake control module located on the rear brake caliper starts rotating, applying braking force to the brake disc. At the same time, the traditional hydraulic brake also engages, making the braking response more agile. When the vehicle is parked, the driver can automatically release the handbrake by pressing the accelerator or applying the brake (reaching a braking force of 10bar).
I often drive cars equipped with electronic parking brakes, so I know a bit about how they work. Simply put, it's about using a button to trigger an electronic system that locks the wheels. When you press that small button, the car's computer receives the signal and controls an electric motor to start operating. This motor, through gears or cables, pulls the brake pads near the wheels, clamping tightly onto the disc or drum like pliers, making the wheels immobile. This way, the car stays firmly in place. What's even cooler is that many modern cars integrate automatic features, such as automatically preventing rollback when parked on a slope. When you press the accelerator to start, the computer detects it and releases the brake automatically. Compared to the old-fashioned lever handbrake, it saves space and is safer and more reliable.
