Bearings: standard, dimensions. Standard size bearings

Bearing is called a special node, which is a part of the support for supporting the shaft and intended for rotation or rolling of the latter without loss of energy to friction. There are several types of such structural elements. Thus, the dimensions of the bearings in most cases are regulated by GOST.

Varieties

Nodes of this type are used in industry and other sectors of the economy are very wide. There are hydrostatic, gas, magnetic and other groups of bearings. However, the most common varieties are the nodes of sliding and rolling. According to the perceived load both of these groups are divided into:

• Radikalnye;

• Opornye;

• Radialno-opornye.

Bearings

The Main elements of nodes of this type are balls or rollers located at a certain distance from each other in a special cage, called a separator. In the process of bearing they roll on the treadmill two rings, one of which is in most cases static. Nodes of this type are used in industry more often. The fact that in comparison with plain bearings, they have a number of advantages. These include primarily small friction and low lubricant consumption. Easy operation and installation — this, also, what is the difference between these bearings. Standards (sizes they are regulated by GOST) of such units is shown in special tables. So find suitable in a particular case bearing special work will not make. A node of this type you can choose absolutely any model of the structure.

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Sensitivity to vibration and shock loads — the only drawback, which differ in such bearings. Standards in their manufacture must be followed. Otherwise, it is too long they will not serve.

Types of rolling bearings

In Addition to the perceived workload, the nodes of this type are classified into groups according to the following criteria:

• The Form of rolling elements. In this respect, distinguish between ball bearings and roller bearings. Rolling body, the latter may be tapered, cylindrical, needle-like, twisted, barrel, etc.

• According to the ability of samostalne. In this case, distinguish between spherical and desmostylians bearings.

• The number of rolling elements. There are single and double row bearings.

• Size. All current day bearings on this basis are divided into several series.

Depending on the series with the same internal diameter, width and bearing outer D can change. Used rolling bearings can in vehicle Assembly, bicycles, windmills, etc.

Dimensions

The dimensions of the nodes of this type defines the GOST 3478-79. When the observance be very sturdy and durable bearings. These standards apply to all types of nodes rolling, with the exception of models for special purposes, with special design. In the latter case, nodes can be made of different sizes, most appropriate for a particular design.

To Find out standard sizes of bearings in each series can, as already mentioned, special tables that specify internal and external diameters, the lower limit size (Rmin) and a nominal width of inner and outer rings (B). As an example, below please find the table for the series of bearings diameters 8 (abridged).

More detailed tables can be found in the specialized literature. There are also standards bearing in the Compass — graphic editor, designed for computer-aided design (in design library). There are tables for different diameters nodes.

Accuracy

Standard size bearings, so you can learn from special tables. However, in some cases allowed some deviations in size from GOST. Class of accuracy of rolling bearings are divided into:

• The normal “0”

• High-accuracy “6”;

• High “5”;

• Osobowych “4”;

• Ultra-high «2».

Nodes for different structures can have well-defined acceptable tolerances. So, for example, standards for Bicycle bearings (608 type) are:

• The tolerances balls — 0/-0.005;

• The inside lane - +0.0001/-0.0003;

• The external paths - +0.0001/-0.0005.

Designations

Standards of rolling bearings during their manufacture necessarily are met. To the consumer could see that the node before it and for what purposes it can be used to apply a special marking. These are the bearings usually engraved set of numbers. Sometimes, standard marking includes the letters. Thus:

• The First number or letter indicates type of bearing.

• The Next two digits define the series node. The first group indicates the width or height, the second — diameter.

• The Last two digits represent a code hole diameter. If you multiply it by 5, we can obtain the value of d in mm.

Standard size bearings 66414 (landing in this case, choose according to GOST 3325-85), for example, are:

• D — 70 mm;

• D — 180 mm;

• Width   42 mm.

• Weight — 5.74 kg.

Plain Bearings

Nodes of this type consist of two main elements: the hull and liner between them to special lubricants. The main advantages of these bearings include primarily small diameters, and also the ability to make them split and used for shafts of very complex designs. The disadvantages of the nodes of this variety are not too long life and the need for costly lubricants.

Types of plain bearings

At the moment there are nodes in this group:

• High speed

• Split (used, for example, articulated shafts);

• Precision machines, accurately guides the rollers and giving the opportunity gap adjustment;

• A cheap low-speed mechanisms;

• Designed to work in specific conditions (water, hostile environments).

Depending on the mode of operation in the bearing of this type can be a liquid or semi-fluid friction. In the first case, the working surface of the housing and the shaft, separated by a rather thick layer of oil. Under semi-fluid friction is added to the liquid boundary (the very thin oil film formed by molecular bonds).

Dimensions of sliding bearings

The dimensions of the sites in this group are defined by GOST 2795. Data from custom tables — it's also what will definitely take into account making such bearings. Standards in this case apply to such parameters as:

• The outer and inner diameter;

• The length (l);

• The chamfer size (C);

• Tolerances (limit deviations).

In the table below (abbreviated) the standard sizes of bearings of different series.

The design features and materials

Standards of bearings, thus, strictly defined standards. Meet some of the requirements and to the quality of the used materials. The body of the bearing, as already mentioned, can be one piece or detachable. In the latter case for the connection parts are special studs or bolts. The liner bearing is executed in the form of a sleeve. In all-in-one node it can be made of two halves. On the shaft subject to deformation, usually mounted self-aligning bearings.

For the manufacture of nodes of this type can be used the following:

• Cast iron (for housing);

• Bronze, cast iron or plastic (for bushings).

In some cases, but of course, very rare, sleeve made of wood or even chipboard.

Basic requirements

Therefore, the bearings are standards (or rather their implementation) allow to produce the highest quality, durable and with excellent performance. Node requirements in this group are as follows:

• Materials and bearing designthe slides must be such as to provide a minimum coefficient of friction between the housing and the bushing.

• The Strength and rigidity of the Assembly should be such that it could withstand the required load.

• Welcome maximum simplicity of construction of the bearing. For its installation there should be no difficulties.

• To Make the bearings should be so that their surface is sufficient for removal arise in the process heat area.

How do

Make plain bearings and rolling on specialized large enterprises, which usually consists of two main workshops: thermal and mechanical. Assembly lines of these factories often operate in automatic mode. In addition, the workshops are also installed modern machines spraying.

In our country the most popular sites, produced by domestic manufacturers, as well as in Switzerland (SKF). Standards SKF bearings are the same as in Russian.