One of the pioneers of the automotive industry, the famous Ettore Bugatti, responding to a complaint about the "weak brakes" of the new Bugatti, allowed himself a joke: "I make my cars so that they drive, not brake." Fate remembered him these words: in 1939, while testing a new race car, the son of Ettore, thirty-year-old Jean Bugatti, died. According to eyewitnesses, he flew out of the road, trying to avoid a collision with a cyclist. Perhaps this would not have happened if his car had more effective brakes.
Tapes and pads
The first brake systems appeared on horse-drawn vehicles. If the horse could not be stopped by pulling the reins, it was necessary to use a hand brake that pressed the leather-padded pad to the wheel rim (the front brake of the simplest bicycles was made on the same principle, only friction material was used instead of leather). But in wet weather, the efficiency was low, moreover, the skin was quickly worn away, and the lining had to be changed frequently.
From horse-drawn transport, such a system was inherited by the first cars. The brake design inherited from horse-drawn carriages suited engineers for two decades! It was a time when the car itself had just won the right to exist …
RetroCar brakes have come a long way from the pads pressed against the wheel rim … Car brakes have come a long way from the pads pressed against the wheel rim …
Retro… to multi-piston hydraulic systems with replaceable carbon-ceramic discs … to multi-piston hydraulic systems with replaceable carbon-ceramic discs
The increase in speed forced to abandon the anachronism - at the beginning of the twentieth century, some cars were already confidently overcoming the 100 km / h line. Therefore, the first "real" brakes were drum, in which pads of an arc-shaped with overlays made of wear-resistant material based on asbestos were pressed against the inner surface of a cast-iron drum. Surprisingly, such brakes are still widely used in vehicles so far, but instead of toxic asbestos, the base of the pads is made up of a variety of materials - from various organic and inorganic fibers to granules of soft metals and artificial graphite, Kevlar and carbon.
In the first quarter of the twentieth century, cars, as a rule, were equipped with brakes only on the rear axle - it was believed that a car with front brakes would "nod", or even roll over. They managed to refute this only in the 20s, but even then the brakes on the front wheels were initially supplied as an expensive option that only wealthy car owners could afford. In those years, the hydraulic brake drive instead of the usual mechanical one became the same gift from some companies. For example, in 1921, for the first time, a Duesenberg Model A was used to use a hydraulic brake system on all wheels, but such a scheme became an integral reality only in the post-war years. Over the years, the handbrake has also improved. At first, its functions were performed by a transmission brake, which was a drum with pads mounted on the output shaft of the gearbox - it was sometimes used as the main one.
Other braking options also appeared: for example, belt brakes, in which a friction belt covered the brake drum.
The brakes became even more effective with the advent of amplifiers, because without them the only way to achieve sharp braking was the physical strength of the driver, and sometimes his body weight. Naturally, not everyone could cope, for example, with emergency braking. The first mechanical brake booster was patented by Louis Renault in 1923, but another European company, the Belgian Dewandre, took up the distribution of this device. In 1927, Albert Devandre created the most successful amplifier design, which he immediately bought the German company Bosch and began mass production.
The first Bosch-Dewandre amplifiers used a vacuum in the engine inlet. By depressing the brake pedal, vacuum applied to the brake cylinder, increasing the braking performance. To the effort developed by the driver, about 30 kilograms were added, as a result of which the braking distance was reduced by 30%. “Feel sorry for the legs!” Read the Bosch advertising slogan of the time. These vacuum amplifiers in the 1920s and 1930s were equipped, as a rule, with heavy trucks and buses, as well as with 12-cylinder models Maybach and Horch, which weighed three tons each.
There was even an electric brake drive, in which the block was pressed against the disk with the help of an electromagnet, but this solution did not find wide application.
The drum was bad
At first, they rejected more successful designs. So, disc brakes have come a long way. Back in 1902, in the United Kingdom, Dr. William Lanchester patented a design that was used on Lanchester automobiles of the same name from 1906 to 1914. But due to low efficiency, they had to be abandoned for a while. But the idea took root in aviation - such brakes were used in the landing gear. Disc brakes returned to the car thanks to racing, only in the 50s. The first production car with disc brakes on all wheels was the British Austin-Healey 100S in 1954, and in droves they appeared on cars in the 70s. For a long time, the brakes of cars on the front axle were disc, and on the rear - drum. This was explained by the fact that it was not immediately possible to select a suitable parking brake drive for the disc brakes because of the great effort required to press the pads to the disc. Another disadvantage was the vulnerability of drives, which in difficult road conditions suffered from overheating and pollution. This was the reason for the appearance of the combined brake system on the VAZ-2101, while its Italian prototype Fiat-124 had disc brakes on all wheels.
RetroDrum brakes on the front axle used to be not only on trucks, but even on racing cars. Drum brakes on the front axle used to stand not only on trucks, but even on racing cars.
Nevertheless, disc brakes turned out to be much simpler, more compact, lighter and cheaper - all this led to their spread. Moreover, due to the free circulation of air, disc brakes are better cooled. Other advantages of such brakes are a simpler operation of changing pads and self-cleaning from water, oil and dust.
Use of electricity
The next stage of evolution was the introduction of ABS - anti-lock braking system. ABS in its modern form was developed in the USA at the end of the 60s by Bendix engineers. The system first appeared on Chrysler Imperial cars in the 1971 model year, but only as an option. The new technology turned out to be insufficiently developed and had a limited scope: it did not solve the problem of blocking the front drive wheels, which posed a special danger, as it led to a loss of vehicle control.
Since 1964, the small German company Teldix GmbH from Heidelberg worked on the creation of an automobile anti-lock system. Its engineer Heinz Lieber developed the fundamental foundations of the future ABS, and soon became head of the electrical and electronics department at Daimler-Benz. And in 1970, Daimler-Benz solemnly announced the creation of the first workable anti-lock braking system.
Complex winter tests of the first sample, called ABS 1, confirmed its effectiveness, but revealed one significant drawback - the unreliability of electronic components. Soon, at the suggestion of Daimler-Benz, Bosch engineers were involved in the project, who also worked on a similar task and had considerable experience. Thus, Lieber's successful ideas and Bosch's experience in the development and production of digital electronic components were combined to create a serial anti-lock system. It is these components that have significantly increased the performance of the central ABS control unit and significantly reduced the number of parts thanks to the use of highly integrated microcircuits.
The new version of the anti-lock system, called ABS 2, was initially installed only by special order on the Mercedes-Benz W114 and W116 models, but since 1978 it has been used in droves. The first production models with standard ABS equipment were the Mercedes-Benz W126 and BMW 7 Series. Today, the anti-lock system has already become a mandatory accessory of a modern vehicle: since July 2004, every new car sold in Europe has been equipped with ABS as standard.
In 1986, when the millionth ABS was launched, Bosch introduced another new product - the Traction Control System (TCS). This system, which was developed since 1980, operates under acceleration according to the same principle as ABS during braking, and prevents wheel slippage. And in 1995, ESP appeared - a stabilization system, also based on ABS technology. The ESP control unit analyzes the data received from various sensors, and in the event of a dangerous situation, such as skidding, intervenes in the control. At the command of the electronics, the desired wheel is braked, which creates a turning moment that prevents the development of skidding and helps the driver maintain control of the car.