Anonim

MARKET

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DISCS IN PADS

BRAKE SHOES -

THIS IS NOT ONLY A TITLE, BUT AND AN INDEX

TEXT / DMITRY NEKRASOV, MIKHAIL KOLODOCHKIN

“Hello, is this a car dealership? Tell me, how much does a VAZ car cost? ”

Funny, is not it? Even the most polite lady on the other end of the wire cannot stand it, because the “classics”, and “Samaras”, and “cornfields” are all VAZs. But about the same "smart" questions we sometimes ask when choosing parts. For example, front brake pads.

Of course, buying just “pads” is much easier than looking for a specific manufacturer, and even understanding the labels on the packaging. However, this is the reason for the examination - we are interested in how the various compositions of the friction mixture of the pads behave during testing, and such information will be useful to everyone. The car model does not play a special role - let it be, for example, "Moskvich 2141".

TEST METHOD

The frictional properties and wear resistance were tested at the STN-NAMI stand in the full-scale unit of the brake mechanism of the Moskvich 2141 automobile. A shaft with inertial masses and a brake disc mounted on it was accelerated to a predetermined speed, and then braked at a given pressure in the working cylinder of the brake mechanism. In this case, the dependence of the braking torque on the pressure in the brake cylinder, on the reduced speed of movement (corresponding to the beginning of braking), as well as on the temperature of the brake disc, was determined. Wear resistance was determined by a micrometer by reducing the thickness of the pads per test cycle. The strength of the friction lining with the block was checked on a special stand of the SGP-1 type.

TEST PROGRAM

1. Lapping pads. Mode: speed - 60 km / h, pressure in the drive - 5.0 MPa. Lapping is considered complete after running in 90% of the lining area.

2. Measurement of the thickness of the pads.

3. Tests of “cold” brakes - temperature not higher than 100 ° С.

3–1. Constant speed and variable pressure mode. V = 80 km / h, P = vario = 2.0, 4.0, 5.0, 6.0, 8.0 MPa.

3–2. Constant pressure and variable speed mode. P = 5.0 MPa, V = vario = 40, 60, 80, 100, 120, 140 km / h.

4. Tests in the heating cycle (type "Girling"). Mode - 25 brakes at intervals of 45 seconds. P = 5.0 MPa, V = 100 km / h.

5. Verification of recovery of effectiveness.

5–1. Constant speed and variable pressure mode. V = 80 km / h, P = vario = 2.0, 4.0, 5.0, 6.0, 8.0 MPa.

5–2. Constant pressure and variable speed mode. P = 5.0 MPa, V = vario = 40, 60, 80, 100, 120, 140.

6. Measurement of the thickness of the pads.

7. Determination of the strength of the connection frame pads with a pad. The methodology is in accordance with GOST R ISO 6312. Two new blocks of each item were tested.

Having familiarized with the program and test procedure, you can proceed to their results. Five graphs are offered for your attention, and each of them has seven multi-colored curves - according to the number of sets tested. First, we study the behavior of the pads in the "cold" state (Fig. 1 and 2, on the left), then according to Fig. 3 we evaluate the tests in the heating cycle, and at the end we return again to Fig. 1 and 2: the graphs on the right show that the characteristics of most pads have changed irreversibly after heating.

Generally speaking, the pads are not in a “cold” state for long, but their behavior during this period should be treated with caution. So, the products of EzATI and TIIR-260 react better than others at the same time: the brakes of the pedal: at a speed of 80 km / h at any pressure in the drive they “catch” better than their colleagues. There are also two lagging behind - DAFMI and TIIR-205.

And at different speeds? Here the STS pads look better than others, showing "independence of character" - their braking torque in the entire speed range was not only constant, but also high. The worst are DAFMI products.

The Girling-type heating cycle is cruel … The temperature of the pads jumped hundreds of degrees after 25th braking. The TIIR-205 products warmed up less than others (exactly 400 ° С), and the STS (about 470 ° С) turned out to be the “hottest”. As for the braking efficiency, the STS pads were leading throughout the cycle - only in the last instant they were caught up with the TIIR-205. Worse than others … however, we will not beat the speed bump - and so everything is visible.

The pads have cooled, "calmed down" - but their character has irreversibly changed. At the same time, SCAR products stood apart - their rather ordinary parameters almost did not change, and they began to react worse to the pedal than in the “cold” form. But all the other pads began to slow down better!

The leader in terms of braking performance at 80 km / h remained TIIR-260, with EzATI and TRANSMASTER quite a bit behind him. The worst, as already noted, was SCAR. But at constant pressure, but at different speeds, STS became the best again. The laggards are all the same: SCAR and DAFMI.

After studying the curves, we move on to the numbers (see table).

The average wear of a block, reduced to one braking, is a curious indicator. However, it was only possible to measure it in four sets of pads out of seven - the rest after heating … increased in size! Swollen, therefore. Not scary, but others do not swell …

TIIR-260 wore the least, and SCAR turned out to be the “softest” ones. I would like to remind you that not only the shoe wears out, but also the brake disc, and therefore, the figures obtained should be treated accordingly …

In tests on the separation force, two samples of new blocks were checked, therefore, the table also shows two indicators - through a fraction. Everything is clear with the leaders - these are both sets of TIIR and DAFMI. But an indicator like “2.5 / 5.2” makes you wonder: double scatter, and even on the verge of exiting the tolerance - this, as they say, is not good.

Well, the dossiers are studied - it's time to give grades. To begin with, all the pads presented in the tests provide braking performance in accordance with regulatory documents. In addition, the strength of the connection between the pad and the pad for all products complies with the requirements of UNECE Regulation No. 90 - the separation force must not be lower than 2.5 MPa. Thus, from a formal point of view, "offset" everyone gets.

As for informal assessments, we liked the sets of TIIR-260 and STS pads more than others - both have something to complain about, but overall they look decent. And less than others … however, and so everything is clear. Extreme assessments - both flattering and abusive - we tried to avoid. And everyone who has their own judgment, they themselves will reach a verdict.

1. TIIR-260

Manufacturer / Russia, Yaroslavl

Price / 180 rub.

Frictional properties (before / after the heating cycle) are good / highest. Durability is excellent. Wear resistance is the best of all. Rating: excellent.

2. STS STD-123

Manufacturer / Russia, Moscow

Price / 140 rub.

The frictional properties (before / after the heating cycle) are good / excellent. Durability is high. Wear resistance is satisfactory. Rating: good.

3. EZATI T-226

Manufacturer / Russia, Egorievsk

Price / 120 rub.

The frictional properties (before / after the heating cycle) are satisfactory / good. Strength - medium, unstable. Wear resistance is medium. Rating: good.

OUR HELP

Alphanumeric indices - TIIR-260, EzATI

T-226 and others - indicate the type of friction mixture used in the pads. Therefore, in the sentence “set of TIIR pads” there is no more information than, say, in the phrase “VAZ car” …

TEST PERFORMANCE TEST RESULTS

AT THE SIZE OF WEAR AND THE BENEFIT

Test type

Amount of wear, mm х10–3 Breakout force (col. 1 / col. 2), MPa

TIIR-260 1.75 7.0 / 6.0

STS STD-123 3.48 6.0 / 5.6

EZATI T-266 2.16 2.5 / 5.2

TIIR-205 * 7.0 / 7.0

DAFMI D2AM * 7.0 / 6.7

TRANSMASTER (DBB) T-779 * 3.5 / 5.2

SCAR 4.80 3.08 / 4.2

* It was not possible to carry out the measurements, since after the heating cycle the pads “swelled” due to insufficient hardness.

Fig. 1. The test results of the effectiveness of the pads depending on the pressure in the drive before and after the heating cycle.

Fig. 2. The test results of the effectiveness of the pads depending on the speed before and after the heating cycle.

Fig. 3. The test results of the effectiveness of the pads during the heating cycle.

4. TIIR-205

Manufacturer / Russia, Yaroslavl

Price / 160 rub.

The frictional properties (before / after the heating cycle) are satisfactory / excellent. Strength is the best of all. Wear resistance could not be evaluated. Rating: good.

5. DAFMI D2AM

Manufacturer / Ukraine, Dnepropetrovsk

Price / 180 rub.

Frictional properties (before / after the heating cycle) are satisfactory / satisfactory. Durability is excellent. Wear resistance could not be evaluated. Rating: satisfactory.

6. TRANSMASTER (DBB) T-779

Manufacturer / Russia, Moscow

Price / 200 rub.

The frictional properties (before / after the heating cycle) are satisfactory / good. Strength is satisfactory. Wear resistance could not be evaluated. Rating: satisfactory.

7. SCAR

Manufacturer / Russia, Yaroslavl