frein

Frein (brake) is a device that reduces or stops the motion of a moving object by dissipating its kinetic energy, typically as heat. In most vehicles, braking relies on friction between a moving part (pad or shoe) and a stationary or rotating surface (disc or drum), though some systems use energy recovery rather than heat. The term frein comes from French, and the English word brake is used in many languages.

Types and applications: The most common automotive braking systems are hydraulic disc brakes and drum brakes. Disc brakes use a caliper to squeeze pads against a rotor; drum brakes use shoes inside a drum. Heavy vehicles may use air brakes, which apply via compressed air. Electric or hybrid vehicles may employ regenerative braking to convert motion into stored electrical energy. Parking brakes provide stationary restraint, often by mechanical linkages or electronic control.

Key components and operation: A master cylinder or pump transmits hydraulic pressure through brake lines; the caliper or wheel cylinder converts pressure into squeezing force on the pads or shoes. Pads or shoes wear over time and are replaced; rotors or drums dissipate energy as heat. Anti-lock braking systems (ABS) modulate braking to maintain steering control under heavy or slippery conditions, sometimes combined with electronic stability control.

Maintenance and safety: Regular inspection of pad/shoe wear, rotor or drum condition, fluid levels, and seals is essential. Overheating, glazing, or contamination reduces braking efficiency. Proper bedding-in of new components and adherence to service intervals are important for reliable performance.

History: Early braking methods used wooden blocks or clamps; hydraulic brakes became common in the early 20th century, followed by disc brakes, ABS, and regenerative braking in later decades.