Translations:Adventist Youth Honors Answer Book/Vocational/Automobile Mechanics/35/en
d. Difference between drum brakes and disk brakes, standard brakes and power brakes, and the parking brake
The diagram on the right shows the parts of a drum brake system. The brake is taken apart in this photo showing the brake drum on the left, and the brake shoes on the right. In operation, the shoes fit inside the drum. The drum rotates with the wheel, and the shoes are held stationary. When the brakes are applied, the shoes press against the inside surface of the drum, and the friction produced slows the wheels, stopping them ultimately.
The diagram on the right shows the parts of a disk brake system. Here, the disk (gold) rotates with the wheel, and a stationary pair of calipers (red) squeeze both sides of the disc.
In standard brakes the energy supplied by the operator’s foot in pushing down on the brake pedal is transferred to the brake mechanism on the wheels by various means. A mechanical hookup has been used since the earliest motor vehicles, but hydraulic pressure is used most extensively at the present time. Mechanically operated braking systems are obsolete on today’s automobiles, but these systems may be used for a portion of the braking systems in many vehicles.
