It is widely known that properly operating braking system is one of the basics of our safety during driving. Average Joe with open mind and basic technical skills knows how to change discs and brake blocks in a vehicle. Does everybody knows what „good” disc and „good” block mean?
The disc or braking block manufacturing and materials used for its production with the purpose for civilian vehicles is relatively simple issue. Additionally, it is added up to the fact that subassemblies are cyclically replaced elements of the braking system, that is why it should not surprise nobody that there is a lot of manufacturers of such elements as well as there is a lot of opinions on its efficiency. Thus, to give the answer what “good brake” means, it is necessary to be sensible of the fact that the value of delays during braking depends mainly on tires traction. The brakes that shall block it immediately will be inefficient (obviously, ABS systems shall not allow for its locking), however these one that allow for braking strength dosing under driver control. Due to this fact, the manufacturers of vehicle brake blocks Include (or should include), softening additives in proper mixtures, for example graphite.
Requirements for braking blocks are as follows:
• silent operations during braking and after it, • low level of fluid emission, • relatively low wear of braking blocks, • high efficiency even in high temperature, • low price.
Obtaining presented technical requirements referring to braking blocks is possible trough the structure and chemical composition of friction lining. Unfortunately, friction material is a far reaching compromise, especially between low wear and a level of dust emission. That is why, “hard” braking blocks are offered in the market that characterize with low dusting but having essential influence on increased wear of braking disc, and „soft” braking blocks with reverse characteristics. Every manufacturer tries to „strike a balance” by developing new mixtures of the friction materials which allow to attain cross-purpose characteristics.
The topic of friction steam – braking block is more complex. Moving vehicle has kinetic energy directly proportional to its weight and speed second power. The task of the braking system is nothing more than decreasing speed through its changing into thermal energy on the surface of a block and braking disc contact. During braking (as a result of a friction of two elements) huge amount of heat is generated and the temperature reach even 400°C, and it is safe value for passenger vehicles. Above this value fading phenomenon happens, that is decreasing braking force.
p align="justify">How to define which out of two discs of the same use can be better than the other? Referring to fading phenomenon and increasing temperature of disc-block system, to put it as simple as possible – based on weight. Why is that? It refers to thermal capacity of the system. The heat capacity is a physical volume determining the amount of heat necessary to change the body temperature/element for one degree. This is, in turn, proportional to the matter amount, that is,
p weight. It will be harder to warm up the disc of more weight and to close to dangerous limits of its operations. Talking about warming up of elements the issues connected with discs cooling can be avoided. Proper project of braking disc regarding internally ribbing for as efficient cooling as possible, is vital so much that directional braking discs, that when are mounted in a wrong manner cannot fulfill assumed cooling, are more and more common.
The operation conditions have considerable influence on discs and braking blocks. It is not widely known that worn elements of steering system, improper tires geometry, tires unbalance or even improper tightening torque influence adversely on braking discs, especially those of huge size, changing its geometrical dimensions through uneven wear. It is necessary to pay attention to the fact that one of mistakes made by drivers, namely keeping brake pedal pressed upon the vehicle stop and after long braking. As was mentioned before, discs cooling is very important thing, and keeping the contact of the braking lock and a disc does not allow to cool elements in this area. Finally, local change in the disc structure occur, and it leads to the change in the friction coefficient and as an effect of it to the decrease in the braking efficiency. The above aspects concern the maintenance period and talks about us more than about products and manufacturers.
Is it all about it? Obviously not. Not less important aspect of future operations of the braking system is the manner of the transport and storage of braking discs. The discs of dimensions exceeding 350 mm and the weight 7,5 – 8 kg can be found in the market, that is why that are heavy elements. Referring to it, the method of the transport and storage is not less important than described physical aspects. The inaccuracy in storing (excessive or uneven loading of discs while storage) can lead to its deformations prior to its assembly.
Being aware of all these (and many other) aspects concerning properly designed and stored elements of the braking system, we present to you the products of QUARO brand elements, that will fulfill your very high expectations. We hope that the reading of this article and the offer on new products shall make that all concerns on the braking blocks and discs manufacturer will be left behind.