Braking types

The front wheel brake is ventilation coil type, the rear wheel brake is disk and drum type. The service brake type is that the doubleloop vacuum assist hydraulic brake is applied on the front and rear disc brake. The parking brake is mechanical dragline acting on the drum brake of the rear wheel. 

There are a couple of configurations of cable-pull brakes. Most common are center-pull, in which one cable reaches straight in between two calipers, at which point the cable splits into a triangle in order to pull both calipers. You may also find side-pull brakes, in which one cable extends down the side of a horseshoe-shaped piece opposite a straight arm. Neither is necessarily better than the other and both work by essentially the same mechanism, but depending on your brake type, you may have to slightly adjust the instructions in this section. 

A minimum ratio of brake force balance across an axle of 0.65 or better for any vehicle or brake type. 

FIG. B-15 Hydrodynamic brake components and brake types (Voith VHBM type). (Source J.M. Voith GmbH.)... 

Phenohc resins are the oldest form of synthetic stmctural adhesives. Usage ranges from bonding automobile and other types of brake linings to aerospace apphcations. These adhesives have a reputation for providing the most durable stmctural bonds to aluminum. Because of volatiles, however, and the need for high pressures, the phenohc resins are used less as adhesives than the epoxy resins. 

Prior to the mid-1970s, the most common type of friction materials in use in brakes and clutches for normal duty for original equipment installations and for the aftermarket were termed organics. These materials usually contained about 30—40 wt % of organic components and were asbestos-based (3). 

Carbon Composites. Cermet friction materials tend to be heavy, thus making the brake system less energy-efficient. Compared with cermets, carbon (or graphite) is a thermally stable material of low density and reasonably high specific heat. A combination of these properties makes carbon attractive as a brake material and several companies are manufacturing carbon fiber—reinforced carbon-matrix composites, which ate used primarily for aircraft brakes and race cats (16). Carbon composites usually consist of three types of carbon carbon in the fibrous form (see Carbon fibers), carbon resulting from the controlled pyrolysis of the resin (usually phenoHc-based), and carbon from chemical vapor deposition (CVD) filling the pores (16). 

In order to define the extent of emissions from automotive brakes and clutches, a study was carried out in which specially designed wear debris collectors were built for the dmm brake, the disk brake, and the clutch of a popular U.S. vehicle (1). The vehicle was driven through various test cycles to determine the extent and type of brake emissions generated under all driving conditions. Typical original equipment and aftermarket friction materials were evaluated. Brake relines were made to simulate consumer practices. The wear debris was analyzed by a combination of optical and electron microscopy to ascertain the asbestos content and its particle size distribution. It was found that more than 99.7% of the asbestos was converted to a nonfibrous form and... 

A. E. Anderson, "Brake Systems Performance—Effects of Eiber Types and Concentrations", Proceedings from Fibers in Friction Materials Symposium, Asbestos Institute, Atiantic City, N.J., Oct. 1987. 

Fig. 2. Effect of mixture strength on exhaust gas composition (dry basis) and brake specific fuel consumption (BSFC) for an unsupercharged automotive-type engine usiag iadolene fuel, H/C = 1.86, where the ignition is tuned to achieve maximum best torque (MBT), the brake mean effective...

Drive motors should be of the high-starting-torque type and selected for 1.33 times maximum rotational speed. For two- or three-diameter Idlns, the brake horsepower for the several diameters should be calculated separately and summed. Auxiliaiy drives should be provided to maintain shell rotation in the event of power failure. These are usually gasohne or diesel engines. 

Auxiliary Equipment Elevating conveyors must be equipped with some form of holdback or brake to prevent reversal of travel and subsequent jamming when power is unexpectedly cut off. Ratchet and wedge roUer-type holdbacks are commonly used. Solenoid brakes and spring clutches may also be employed. 

There are several methods of braking, external or internal, and they are briefly diseussed below. Any of them can be employed, depending upon the torque requirement, i.e. size of motor, its speed, the type of load, etc. 

This type of braking is suitable for small motors and can be achieved through... 

In the first two types a brake shoe, operated by an external auxiliary supply, is mounted on the extended shaft at the NDE (non-driving end) of the motor. These brakes are normally operated after the motor is switched OFF. The heat of braking appears in the external circuit and the motor windings are not affected. For motors with this braking, only the starting heat need be considered, depending upon the frequency of starts and not the heat of braking. 

I In both the above types of braking systems, a hand-operated device is also provided, to release the mcehanieal brakes in applieations such as lifts, elevators, cranes, and winders. This... 

Due to excessive starting and braking heat losses it is not advisable to switch an induction motor ON and OFF frequently. The number of starts and stops a motor is capable of performing will depend upon its working conditions such as type of switching, braking and load demand etc. and can be determined from... 

A b = factor of braking, which depends upon the type of braking used, such as... 

Duty types. S, S, and. S5 as discussed in Chapter 3 are normally applicable to crane and hoist motors. For duty types S4 and 5. the duty cycle per unit time is greater than S, . The most important factor is the number of switching operations per hour. A temperature rise in the motor occurs during acceleration, braking and reversing. 

Compressors are usually high-cost items, but easily correlated by brake horsepower vs. S/horsepower. Variations in engine-driven reciprocating compressor prices can be caused by the type of driver, the speed (the slower the speed the more costly, but the more reliable), the total discharge pressure, and the size. 

A device that can be fitted to a tank truck to prevent anyone from driving it away while a hose is connected is described in Reference 2. A plate is fixed in front of the hose connection. To connect the hose, this plate has to be moved aside, and this applies the brakes. Reference 3 describes a special type of hose that seals automatically if it breaks there ai e also other types. 

The use of flax fibers in car disc brakes as a replacement of asbestos fibers is another example of an application of this type of material [7]. 

---