The German company Jurid, a major manufacturer of brake pads for cars, trucks, high-speed trains and airplanes, invited journalists to test their products.
A brief acquaintance with the training ground, safety training - “come to the car”. The test pilot sets up the measuring equipment, asks to buckle up … and kilometer posts of a high-speed oval flashed outside the windows of the BMW Seven.
The speedometer needle crossed the 250 mark. Speed is almost not felt, only the restrictive barrier looms frighteningly a few meters from the side window. The car enters into a bend - a correctly calculated profile frees the driver from driving. The pilot takes his foot off the accelerator pedal and smoothly brakes to 110 km / h. Numbers ran across the laptop screen - the temperature of the brake discs crawled up sharply.
Again acceleration to the "maximum speed" and smooth braking. At the end of the second cycle, the temperature of the discs on the front and rear axles reached 450–500 ° C, a slight vibration and additional noise appeared. Probably unsweetened pads now! The driver turned around and nodded warningly: they say, I brake “to the floor” … Belts were kept from contacts with interior details, and there was a chatter of an anti-lock system and a slight yelping of tires in my ears. The devices confirmed the sensations - the pedal effort, its progress, the deceleration of the car remained in tolerances, which means that the braking efficiency did not fall. Without letting the parts cool down, the tester performs several more smooth braking at maximum speed. The temperature of the disc jumps to 700 ° C, but the brakes remain tenacious. Test passed - pads approved for mass production.
For cars, it’s easier to use a gentle method - we tested a Mercedes A-class under such a program. The pads must withstand 10 brakes on the floor in a row from 115 km / h.
But proving ground tests are the last exam. The life of the pads begins in factory laboratories about two hundred kilometers to the south, in the small town of Glinda, near Hamburg.
One of the most important elements of the brake pad is the pad. It is over its composition that experts conjure most of the time in search of the perfect recipe. Creating new material, chemists select about 30 components from 200 offered by suppliers.
There are three basic requirements for a modern block: safety, durability, comfort. Going through various materials of overlays, "Dzhurid", like most major manufacturers, reached high rates in the first two points. Therefore, one of the serious tasks for today is to reduce the noise arising from braking. Environmentalists are making more stringent claims - asbestos, lead, cadmium have disappeared from their blocks through their efforts.
The composition is approved, the components fall asleep in the bunkers. Automation clearly doses their amount, diluting with alcohol-containing solvents. Next, the press machine measures the desired volume of dense mass necessary for one lining, "pours" on a metal frame. It is curious that for thermally loaded brakes, Metlock coated frames are used, on which the pad is pressed without glue and held mechanically due to the strong bonds between the molecules.
In the next workshop, the surface of the lining is polished so that freshly baked blocks from the first kilometers provide effective braking. Holes are drilled in the frames for attaching installation springs and wear sensors. The shoe is varnished and a film is glued to the frame to reduce noise and improve heat dissipation.
However, before the test site, several sets from each batch undergo mandatory tests at the stands. By the way, much of the equipment is produced right here at the Jurid plant in Glinda. New models of pads are checked for wear resistance, performance at high temperatures, measure vibration and noise. Relatively recently, equipment appeared on which not only brake mechanisms are tested, but also suspension assemblies.