Decoding bearings according to the domestic designation system

How to determine its main dimensions and type based on the bearing markings?

In accordance with the accepted system of symbols for bearings, the numbers in the markings are counted from right to left.
The first and second numbers (on the right!) indicate the diameter of the shaft at the landing site (inner diameter of the bearing). Internal diameters from 10 to 20 mm are designated as follows:

For bearings with an internal diameter of 20 mm and larger (up to 495 mm), the same first and second digits show the quotient of the diameter size divided by 5. For example, the two rightmost digits 04 mean that the internal diameter of the bearing is 20 mm; numbers 25 correspond to a diameter of 125 mm, etc. The third and seventh numbers indicate the series of bearings by diameter and width, respectively. The fourth indicates the type of bearing: radial ball single row - 0; radial ball double-row spherical - 1; radial with short cylindrical rollers - 2; radial roller double-row spherical - 3; roller with long rollers or needles - 4; roller with twisted rollers - 5; angular contact ball - 6; roller conical - 7; thrust ball - 8; thrust roller - 9.

These are, of course, only the most general designations. It is simply impossible to present everything in a short answer.

Series

bearing is one of the normal rows established by the standards, differing from each other in the diameter of the outer surface and width with the same design and bore diameter. The type of bearing determines its basic properties: the direction of rotation and the shape of the rolling elements.

The variety of types and shapes of support nodes makes it difficult to choose a specific one. You can select a bearing by size from the table online. It's actually not that difficult to decide. To do this, you need to carry out a simple procedure for measuring an existing part that needs to be replaced or use already known parameters. If you follow the rules, you can select a specific model and order its purchase without leaving your home. Let us consider in detail how to do this so as not to make mistakes when purchasing new spare parts.

Designation of imported bearings - is there a foreign GOST for marking components?

If with domestic products everything is clear and each manufacturing company is obliged to adhere to the established numbering requirements for years, then abroad each manufacturer himself comes up with a system convenient for him. Usually it is less detailed and detailed than in Russia, and also has the following drawback - without detailed instructions, and for a Russian person translated into his native language, nothing is clear. You can trust the seller, but he himself often does not know the smallest details that make up the code.

How to determine the bearing series - instructions

There are four main categories. Extra light (number 1), light (2 or 5), medium (3 or 6) and heavy – 4.

To determine which of them the model belongs to, you should find the core of the marking; it is located between two dashes. If there is no suffix or postfix, then the number may stand alone. There are two situations. If there is a slash, then the indicator we need is the first one to the left of it. If there is no slash, then it is third.

How to find out the hole diameter - instructions

These are the very first (right) numbers of the kernel.

If the entry contains the ending - 0X, then this X is a number from 1 to 9 in millimeters. If the entry is 05X, then X is a rounded number, but not more than 10 mm.

The signs 00, 01, 02 and 02 indicate a range from 10 to 20; the code can be converted into exact values ​​using the table above. If they are followed by 9 (i.e. 900 or 901), then again rounding has occurred.

If there is any two-digit value, it should be multiplied by 5. The rule with “nine” in third place remains appropriate here.

And if there is a slash in the marking, then either this is an exception, or the large diameter is more than 50 centimeters.

How to determine its external dimensions by the bearing number - instructions

This is the last kernel value. It stands on the edge, to the left. These are the dimensions, that is, the multiplied width and height. If the inner ring remains the same, then the outer one increases according to the following markings: 0, 8, 9, 1, 7, 2, 3, 4, 5. The ratio of the values ​​can be determined using the table.

How to find out the number

The easiest way is to use electronic catalogs containing all dozens of values. Numbering is easier to master if you first measure the main parameters - outer and inner radius, width, height.

How to choose online bearings by size

There are many online services that provide the opportunity to select a part based on various parameters. Most often, 3 main quantities are used for searching:

• • inner diameter;
• • width (or height);
• • external diameter.

It is important to enter numerical data correctly. First of all, the internal hole of the support assembly is measured, then its external dimensions and only after that the width of the part.

Based on the search results, not one, but several supports with the same parameters and analogues for each of them can be returned. Some services even give an approximate cost for a particular type of part. All that remains is to choose the most suitable one in terms of price and availability.

Forms

Sometimes you can select based on other parameters: a specific name or type. So, you can easily find several analogues if you cannot purchase an original nodal support.

Even knowing all the parameters and observing the correctness of entering data into the search form, it can be difficult to settle on a specific choice. In this case, the staff will provide assistance. They will help you choose the most suitable option based on the characteristics of the machine in which the product will be used.

How does a digital caliper work?

There are three modifications of calipers, they are divided according to the method of taking dimensions.

1. The simplest vernier models can be used for home needs. Integer values ​​are taken from the bar, the fractions are determined by the vernier - these are the basic rules for how to use a vernier caliper.
2. The mechanical measuring principle is used in dial models. Through a gear transmission, fractions of a millimeter are transferred from the rod scale to the dial, and whole values ​​are taken from the rod.
3. The most convenient and accurate is the digital option, where all results are obtained from the display screen. The electronic part itself can be customized, making it even more convenient to use.

To understand how to use it, you need to understand how a digital caliper works. The work is based on a digital capacitive vernier: inside the device there is a capacitive matrix, several plates, the main ones being the stator and the slider. When taking calculations, they are displayed on the display, the stator is located on a mechanical ruler, and the rotor is located under the display itself.

How to choose the right size online

You have to measure the main values ​​of the reference unit yourself, and at this stage you can make several mistakes if you don’t know some tricks.

How to select a bearing according to the inner diameter of the shaft - d

Most questions are associated with its definition, since many types of products have a specific shape. When measuring, you must remember:

• • When selecting an element with a tapered hole, the internal diameter is measured along the smallest side.
• • Thrust bearings use a tension ring to determine the size.
• • If the part is accompanied by a sleeve, then it is inside it that the measurement is taken.
• • If the shape of the internal hole is different from circular, the calculation is carried out along the inscribed circle.

Sometimes the support unit is made without a ring at all. Then the diameter is measured not on the product itself, but on the working shaft. Knowing such little things, it will be much easier to find the bearing number by size online.

Calculation of external diameter - D

Regarding this parameter, everything seems much easier and in most cases, it is so. There are only two nuances. The first concerns the missing outer race ring. If your part has this feature, you can measure the value using the seat.

The second concerns technical characteristics. The outer diameter is classified into spherical and bombed type. The latter is found only in support roller ones and is associated with their complex profile. Unlike the internal diameter, the external diameter can have two values ​​at once: standard and a parameter measured along the locking part.

Width calculation - B

When measuring this part of the part, it is necessary to take into account several nuances that relate to a specific type of product. For example, in a thrust-conical assembly, the ends of the cage may not be the same. In this case, the width is the difference in the dimensions of the two rings. It is important to take measurements in parallel. If difficulties still arise, it is better to seek advice from a specialist.

Shielding, bearing seal in bearing number

The last letters of a bearing indicate the presence/unavailability/type of shielding or seal and other features of the bearing. Different types of readings:

So we can now determine that in the case of the 6305ZZ bearing, the last letters " ZZ " mean that the bearing is shielded on both sides.

Coming to a conclusion, we can now easily decipher the bearing number of most bearings. Here Bearing 6305ZZ means “it is a medium strength single row deep groove ball bearing with a bore diameter of 25mm and shielded on both sides.

Selection of bearings according to parameters

The technical characteristics of the products are not limited to the listed values. The choice is influenced by many other data:

• • The maximum magnitude of the load by its nature and direction. Some parts can only handle radial and axial pressure, while others can handle mixed loads successfully.
• • Number of maintained revolutions per minute. The best performance here is characteristic of nodal rolling bearings.
• • Accuracy class, on which the rotation of the device, and hence the overall operation of the structure, depends.
• • Type of lubricant used (liquid, gas, etc.).
• • The moment of fatigue, that is, the maximum service life of the product.
• • Noise and vibration levels.
• • The actual dimensions, which have already been discussed earlier.

It is also important to take into account the operating conditions of the bearing, including temperature conditions, the ability to use it in water and other features. It can be difficult for the average person to decide on a specific type of support, and the selection form on the Internet is very limited and does not take into account most of the listed parameters. So it can be difficult to do without additional consultation from specialists, especially if the product is purchased to operate an expensive machine.

How to check a caliper for accuracy?

When asking the question of how to use an old caliper, we remember that correct results can only be obtained from a proven tool. Once a year, professional calipers are checked, and before using them even at home, it is better to pay attention to the main possible inaccuracies.

1. The first thing to check is the coincidence of the zero line and the presence of a gap between the shifted jaws.
2. On a flat surface, check the zero line on the depth gauge.
3. It is important that the movable jaw carriage does not move when the caliper is tilted.
4. In the electronic model, much depends on the timely change of the power source.
5. It’s also a good idea to find out the accuracy class of the caliper, since sometimes you need to determine some measurements as reliably as possible. The first type refers to the so-called household calipers, when a reading of 0.1 mm is enough. For more accurate measurements, tools of the second and third types are needed, where the reading value is already 0.05-0.01 mm.

Purpose

There are 3 widely used types: sliding, rolling and magnetic. They differ in their design and scope of use. The first group consists of a body with a hole, a bushing and a lubricating device. To operate such a product, a large amount of lubricant is required, so a technician is required to regulate its supply. Today, this type of parts is used less and less, but they can be found in any equipment that requires high-speed operation, in steam and turbine installations, in navigation systems and many other high-precision devices.

Rolling bearings are by far the most commonly used. Basically, bodies are made in the form of balls and rollers. The main difference between these products and the first type is that there is no need to constantly lubricate the structure. The element can be used for a long time without this material, which means constant supervision by a specialist is not required. The variety of rolling bearings allows them to be used literally everywhere: from electric motors to household appliances, from complex industrial machines to medical equipment.

Magnetic devices are a structure that operates on levitation. It may include the product itself, an electronic system for monitoring its operation, or permanent magnets. The scope of application of such parts is very wide and unusual compared to others. They are often used in complex gas centrifuges, cryogenic technology, turbomolecular pumps and other mechanisms.

It is the specific type of bearings that becomes the basis of choice, since these parts are not interchangeable, although they can protect each other.

Single row roller bearings - table with dimensions

Single row roller bearings

FKL produces single-row radial rolling bearings in accordance with DIN 5412 part 1 and angular rings in accordance with ISO 246 and DIN 5412 part 1. These bearings are split. This makes installation and disassembly easier, and the contact of both rings can be tight. The contact line between track and rollers is modified to eliminate edge stressing. The ability to compensate for the angular error of these imported bearings for narrow rows 2, 3 and 4 is 4 arc minutes, and for wider rows 22 and 23 - 3 arc minutes.

Single row cylindrical rolling bearings are available in the following types: NU, N, NJ, NUP, NF, NU+HJ, NJ+HJ

Single row roller bearings. Data

Clips

The clips are mainly made of stamped steel sheet. Massive cages are made of brass (additional designation on bearings is M).

Temperature Application Range of Roller Bearing

Cylindrical bearings with a cage made of steel sheet or with a brass cage are used up to an operating temperature of 150 0 C, taking into account the material and heat treatment of the outer and inner rings.

Roller bearings without inner ring (RNU)

The bearing rollers without inner ring (RNU) run on a hardened and ground shaft whose dimensions F are machined to G6 (housing bore to K6). Shaft diameter J is machined to tolerance h9 (F and J - see bearing size table).

Classification according to various criteria

All types of nodal supports are classified according to different features, and some of them even according to several. What is common is the division according to the type of perceived load. According to it, all devices, regardless of whether they provide rolling or sliding, can be divided into:

• • Radial – remove a perpendicular load directly from the axis of the part.
• • Thrust – take the load from the shaft axis.
• • Thrust-radial or radial-thrust – combine the properties of the first and second.

The strength of the perceived load can also vary, so it is not enough to select a bearing based on its type; the maximum force must also be taken into account.

Another general indicator for classification is dimensions. According to them, all supports are divided into series. Each combines information about diameters and widths. Each device can be assigned a number from 0 to 9, with non-standard sizes designated 6, 7 or 8.

And finally, the most important indicator for classification is design features. Here the variety is very wide and is indicated in the markings by two-digit values ​​from 00 to 99. For example, rolling bearings are divided into ball and roller bearings according to the shape of the body. The first are further divided into:

• • Cylindrical.
• • Conical.
• • Needle-shaped.
• • Spherical.

This variety allows you to increase the perceived load, noise and vibration levels, wear resistance, rotation speed and so on. Ultimately, all bearings are individually marked, taking into account the features of the device. It specifies the diameter, dimensions, type, design differences and some additional signs for complex parts.

The search for a new nodal support should begin by studying the instructions for the old one. All parameters must be specified in it. If such information is not available, selection is made by size. Then, taking into account the operating conditions and the specific characteristics of the machine into which the support is inserted, other basic indicators are selected. Assistance in choosing when purchasing will be provided by specialists who have extensive experience and understand all the intricacies of the process.

How to measure the diameter of a steel pipe?

Measurements are taken in millimeters along the outer diameter, and in inches - along the inner diameter. This means that to connect through a plastic fitting, you need to measure the outer size of the pipe, and in order to install a metal one, calculate Dу.

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Benefits of bearings

Each type of support unit has its own unique advantages and disadvantages. But there are also common advantages, which is why their exploitation is so widespread.

Firstly, the operating time of the machine increases, since small parts take on an impressive part of the load. Accordingly, wear occurs later, and repairs are required much less frequently. Secondly, with the help of these products it is easy to increase the accuracy of certain parts of the structure. Thirdly, servicing the mechanism requires less effort, time and money. And finally, they are able to expand the functionality of the equipment in which they are built.

Rolling

There are a number of unique features that distinguish this type of device from another common type - sliding. Here are the main advantages:

• • Supports with rolling elements show a low coefficient of friction, which means they demonstrate better performance with minimal physical costs.
• • You can purchase this type of parts ready-made and install them into the mechanism yourself.
• • Products always comply with the standard, so they are very widespread, which means they can be easily found in the store.
• • The cost of this type compares favorably with others due to its wide distribution and mass production at leading factories that comply with GOST.
• • They operate successfully over a wide range of loads and speeds, making them easier to operate and maintain.

These support units still have some disadvantages. They are associated with reduced rotation accuracy compared to others.

Slip

The prevalence of this type of parts is decreasing every year, but in some conditions it is simply impossible to use rolling bearings. Main advantages of the type:

• • The rotation speed at which devices can operate is much higher than when using the first option.
• • They can easily withstand strong shock and vibration loads, which makes it possible to operate in difficult conditions.
• • With the same power, products can work in different environments, including water.
• • Split sliding elements are used on large crankshafts, and the amount of clearance can be adjusted.

Such features allow the use of nodal supports in high-speed mechanisms.

Brief information about multi-row installation

Such a decision is made in order to increase the load-bearing capacity of the unit and reduce the load on a single product. This is extremely important in high-speed supports.

The main condition for long-term and reliable operation is the uniform distribution of the load on each element of the bearing assembly. For products designed to withstand axial loads, this issue is quite simply resolved by ensuring the required manufacturing accuracy of the seating surfaces of the existing races, and the use of bearings with housings of equal rigidity (optionally, elastic).

Pros and cons of using

The design features of parts directly affect their useful properties and disadvantages. Let's look at them separately.

Rolling

Among the undoubted advantages of this type of device are:

• • Low cost. This factor is especially relevant given that in some complex mechanisms up to several hundred support units can be used simultaneously.
• • Low friction does not lead to serious losses and strong heating. And in general, the supports behave equally well both at the start of operation and in an already established stable operating mode.
• • A wide variety does not exclude the interchangeability of parts, and easy installation allows you to make repairs quickly and efficiently.
• • For normal operation, virtually no lubricants are needed.
• • Overall, much less care and attention is required to the parts in which these products are installed.

On the downside, rolling devices are quite susceptible to shock and vibration loads due to their rigid design. This precludes their use in some machines. In terms of their dimensions, the products that provide rocking are large, and the work takes place in quite a lot of noise.

Slip

Among the advantages of use are:

• • Small size.
• • The design can be either detachable or prefabricated.
• • Performance in high-speed mechanisms is significantly better than that of other devices.
• • They are resistant to shock waves and vibrations, which increases the possibility of operation.
• • Works in the most adverse environmental conditions.

Among the disadvantages are:

• • The need for constant monitoring of the lubricant level, since without it the technical characteristics deteriorate significantly.
• • During start-up, large losses occur.
• • Efficiency is lower than in rolling bearings.
• • Expensive raw materials are used for production, which increases the overall price.
• • Components are produced unevenly, which complicates the maintenance of the entire machine as a whole.

You can search for a bearing by size online, but many other key parameters will still have to be determined additionally. With the right choice, you can ensure stable operation of the machine and reduce the need for maintenance. Sometimes it is better to seek help from professionals who will answer your questions and advise which option to choose.

A wide range of assemblies are found in stores and factories. Each of them is designed for its own task, meets a number of requirements, and is also suitable in size for the specified spare parts. In the article we will give a breakdown of the symbols and bearing numbers.

Basic digital markings and diagram

The main thing you need to find out from the seller is which country manufactured the products. The fact is that the accepted norms and standards of Russian and foreign manufacturers differ. For the former, a domestic quality mark is prescribed - GOST 3189-89. It is always observed, this is strictly monitored by supervisory services, since failure to comply with production requirements threatens not only a discrepancy between the order (and it may be a state order) and the final result, but also emergency situations in production.

This part is one of the very important components in virtually every device where mechanical rotational movements are important. Significant damage is usually associated with its deformation. Therefore, you can be sure that when you buy bearings with numbering, you can completely rely on it.

First, we will consider domestic products, since they are more accessible and quite reliable, therefore they are used more often. They look something like this:

Y – XXXXXX – Z

Any number has three components:

• Core (X). Located in the center, it represents a database with basic data about the part. Expressed only in numbers. Six characters represent five indicators. There are hyphens on both sides.
• Prefix (Y). From the name it is clear that this is a preposition, that is, there is an identification mark at the very beginning. Can combine various sign systems. Expresses three interrelated meanings.
• Suffix (Z). Completes the combination and contains a lot of information. Consists mainly of letters of the Cyrillic alphabet (according to Russian GOST), but can be specified with numbers.

Here is a diagram with a breakdown of the markings of rolling bearings (its core)

Х(5) ХХ(4) Х(3) 0Х(2) Х(1)

where by numbers we mean:

1. hole diameter - about this in more detail below;
2. series size, that is, dimensions - multiplied coordinates and their values;
3. node type - from 0 to 9, but the entire list below will be presented in the form of a table, because without it it is difficult to remember this classification;
4. product design - a lot of codes are given for this category, up to 99 pieces, we will not list them in detail, but we will point out that the full list is in the document GOST 3395-89;
5. dimensional category - the very initial number is responsible for a series of widths or heights, highly depends on the radii and cannot always be entered, especially when this indicator is non-standard.

The main difficulties arise when we talk about the size of the inner ring. What if it is larger than 9 mm? After all, only one figure is allocated for this indicator. But what if, on the contrary, the radius is so small that multiplied by 2 it does not even reach the minimum unit to fill the indicated cell of the number? Let's look at it below.

Brief information about multi-row installation

Such a decision is made in order to increase the load-bearing capacity of the unit and reduce the load on a single product. This is extremely important in high-speed supports.

The main condition for long-term and reliable operation is the uniform distribution of the load on each element of the bearing assembly. For products designed to withstand axial loads, this issue is quite simply resolved by ensuring the required manufacturing accuracy of the seating surfaces of the existing races, and the use of bearings with housings of equal rigidity (optionally, elastic).

It is more difficult to evenly distribute axial loads. The slightest errors made during installation, or an incorrectly sized bearing can lead to the fact that only the outermost bearing will take this load, while the rest either fall out completely or take it in small amounts. The issue is resolved by using preload.

As a rule, such a block uses two to four bearings having the same values ​​of D and d.

Bearing sizing options

There are several options for solving this issue, the main ones are:

As a rule, only the main bearing dimensions are determined. This:

Let's consider the first option in relation to a domestically produced bearing.

The bearing number can be found:

Decoding is carried out in accordance with current regulatory documents (for domestic bearings, this is GOST 3189-89).

The two right digits indicate the d value (up to 20 mm inclusive). With a diameter of 20

For imported bearings, it is necessary to follow other standards (taking into account the brand of the product).

At the same time, you should definitely remember that domestic and international markings differ, which can lead to a significant error when determining sizes.

A number of foreign manufacturers label their products according to the company’s internal rules.

If the complete bearing number is not available, follow these steps:

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