LEEVENSPARK

Disc-brake Assembly A disc-brake has a rotating cast-ion disc, bolted to the wheel hub and a stationary caliper unit. The caliper straddles the disc and is bolted to the stub-axle or swivel-post flange. It is made of cast iron in two halves (Fig. 28.25) and each half forms a separate cylinder block with the cylinder axis perpendicular to the disc. The two cylinders are connected together by drillings at the pressure faces of the two caliper halves near to the inlet port (Fig. 28.25B). A bleed-screw drilling also intersects at this junction Fig. 28.25. Double-piston-caliper disc brake Each cylinder uses a rubber sealing in the form of a ring located in a groove in the body and a hollow piston protected by a dust-cover. A friction pad in the form of a segment is bonded to a steel plate and is sandwiched between each piston and the disc face. These pads fit into slots formed in each half of the caliper housing and are held in position by retaining pins, or spring plates. The application o

Disc Brake Cooling The cooling of the brake disc and its pads takes place mostly by air convection, however wheel hubs also conducts away some of the heat. The rubbing surface between the rotating disc and the stationary pads is exposed to the frontal air stream of the vehicle and hence to the directed air circulation. Therefore, under continued brake application the disc brake is consid­erably more stable than the drum brake. Also, the high conformity of the pad and disc, and the uniform pressure allows the disc to withstand higher temperatures compared to the drum brake. Since far less distortion takes place in discs compared to drums, the disc can operate at higher temperatures. Also, the disc expands towards the pads, whereas the drum expands away from the shoe linings. Consequently, in the hot condition the disc brake reduces its pedal movement, but the drum brake increases its pedal movement. The discs are made of cast iron and are ventilated to considerably improve the cooling

For more than 80 years Machine Design's experienced team of engineering degreed editors have provided the news, applications, in-depth technical information, new products and vendor information engineers need and trust. It is written and edited for the individuals who perform a design engineering function. It provides technical information in the following areas: 1.Design and development, how-to, in-depth technical articles 2.Current technical news coverage 3.Ideas, examples of how someone else solved a design problem 4.Personal, professional and management information 5.Commercial assistance by means of new product announcements and manufacturers literature listings Geographic Eligibility: USA, Canada Offered Free by: Penton Media, Inc. Machine Design, Free Machine Design Subscription Subscription

Image by Jeremy Brooks via Flickr