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ROBERT FISHER AND THE CLASSIC HUB

Imported bearings are good and expensive. Ours are worse, but much cheaper. But to understand what the 11th world chess champion has to do with it, you still have to read the article.

Mikhail KOLODOCHKIN

The long-standing procurement officers remember Soviet times very well: if, for example, the horse breeding department suddenly included in its quarterly application roller bearings of the type 6-7805U and 6-7804U, then this means that the head of this department was able to acquire the brand new Lada and slowly begins to collect repair kit for them. These bearings are installed in the hubs of the front wheels of the entire "classic". Almost the same, only of lower quality, are often used in the supports of the hubs of trailers for cars. The differences in the notation are “zero” instead of “six”: these numbers characterize the accuracy class.

The bearings of the front hubs to the rear-wheel drive VAZs are made by the Moscow Bearing Plant (GPZ-1), the Samara Bearing Plant (SPZ-9), the Volzhsky Bearing Plant (VPZ-15), as well as respected foreigners - which only His Majesty SKF is worth … It is these products that were purchased by us in retail for examination. Rodless "pieces of iron" without markings, unfamiliar with moisture-proof paper and other attributes of normal packaging, were rejected without hesitation. We immediately inform the price - we managed to buy Moscow bearings (photo 1) for 45 rubles, Volga (photo 2) - 50, Samara (photo 3) - 55, and Swedish (photo 4) - as much as 450! We draw attention to the marking of the “Swedes”: the analogue of the outer bearing 6–7804U is designated LM 11910 / Q on the outer ring and LM 11949 / Q on the inner. An analogue of the inner 6-7805 is designated 639154 / Q on both the outer and inner rings.

During the tests, the vibration level of the bearings and their overall dimensions, as well as the geometry and accuracy parameters of individual parts, were measured. Dozens of tables from the official protocol really wanted to get into the magazine, but, alas, the chain mail is short … Therefore, we restrict ourselves to brief comments.

In terms of overall dimensions, all bearings are within the norm. The same applies to the roughness of the landing and working surfaces, as well as to the corners of the cones. Due to the inconsistency of the diameter of the raceway of the outer rings, the largest deviations were recorded for Moscow bearings 6–7804U. On the radial and axial beats of the rings, Volga bearings followed the leaders (read, for SKF!), Then the Samara bearings, and then, unfortunately, the Moscow bearings again …

Generally speaking, the results of their vibro-acoustic studies can serve as a comprehensive indicator of the quality of a bearing. Averaged data on internal and external bearings are given in table. 1 and 2.

In general, the winner was known before the start of the test. In almost any of the tables mentioned, the best indicators invariably corresponded to the “Varangian guest”. The leader once again showed what is the difference between the first racket of the world and, say, the twentieth. As a result, the experts assigned the following places: SKF, VPZ-15, SPZ-9, GPZ-1. It was noted that all the bearings under investigation are suitable for installation in the hub assemblies of rear-wheel drive VAZ vehicles.

INSTEAD OF EPILOGUE

It's time to still explain what Bobby Fisher has to do with it. The fact is that the great American chess player was at one time so stronger than everyone else that he once won an unusual honor. The next book dedicated to him described … all the games he lost!

For any athlete, this would be a slap in the face, but Fisher, whose every loss was a sensation, such a publication only added credibility. Let’s try and we will evaluate the results of the examination from this point of view: but were we not even ahead of the eminent Scandinavians at any stage of testing?

Imagine yes! Two protocols of vibro-acoustic studies confirmed that the Volga products in the frequency range 50–300 Hz were 2-3 dB better than the Swedish ones. Deviations of the outer diameter of the Volga and Samara bearings are also 1-2 microns less. And measurements of the geometric parameters of the rings again brought VPZ-15 to the first place - the roughness is smaller, the inconstancy of the diameter is smaller, the beating is the same … I just want to remember the banal phrase: “They can, if they want!”

We will rejoice for individual domestic manufacturers and … lick our lips on SKF inaccessible to most Russians: nevertheless, they won a clean and well-deserved victory. Comedians are right: it must be admitted that for some reason good things always cost a lot …

EXPERT ADVICE OF BEARING INDUSTRY INSTITUTE

As a rule, hub bearings nursing a hundred thousand kilometers. Naturally, the mileage depends on the operating conditions - the worse the road, the worse the bearing.

After running the first 2-3 thousand km, you need to check the axial clearance in the pair of bearings - during this period, intensive running-in of parts occurs, and therefore the play can increase. The normal axial clearance should be between 0.01-0.06 mm.

When replacing bearings, the free cavity between them must be filled 1/3–1/2 with lubricant. Lubricate the space between the rollers. If dirt gets inside, the bearing will not last long. Every 20 thousand km add fresh lubricant. Try to remove old grease by flushing the bearing in kerosene or gasoline. The most affordable lubricant is Litol-24. Among foreign ones, one can recommend LGMT2 or LGMT3 (SKF), Alvania 3 or Cyprina 3 (Shell), Mobilux 3 (Mobil), Castrol LM (Castrol), etc. One should forget about Solidol - it is much worse .

The first sign of a bearing’s “illness” is noise in the assembly. If damage is detected on the surface of the rollers or on the raceways of the outer ring in the form of metal spalling or small dents, then the bearing will have to be replaced. By the way, it is unacceptable to replace one defective inner ring without replacing the outer - the angle of the cone of the new ring may not coincide with the angle of the outer ring of the bearing left in the hub. Remember: when mounting the outer ring, do not hit it with a hammer. As a transition sleeve, which is not a pity, usually use a dismantled ring. And it is best to use a press to install the outer ring.

Table 1

VIBRATION LEVEL LIMITS

ON VIBRATION RESISTANCE OF BEARING TYPE 6–7805U

AND HIS ANALOGUES

Manufacturer Limit values ​​of vibration level, dB,

in the frequency ranges, Hz

50–300 300–1800 1800–10000 General

level

GPZ-1 72–80 73–78 79–83 81–85

SPZ-9 71–76 74–79 76–80 79–82

VPZ-15 65–71 68–71 68–76 73–77

SKF 67–74 66–68 63–65 71–75

table 2

VIBRATION LEVEL LIMITS

ON VIBRATION RESISTANCE OF BEARING TYPE 6–7804U

AND HIS ANALOGUES

Manufacturer Limit values ​​of vibration level, dB,

in the frequency ranges, Hz

50–300 300–1800 1800–10000 General

level

GPZ-1 69–71 76–79 79–81 81–83

SPZ-9 71–74 73–83 73–79 78–85

VPZ-15 61–67 64–66 70–72 72–73