Bearing is in simple words: How the heart of mechanics works

Imagine a massive shaft that should spin at a tremendous speed. If you just insert it into the hole of the case, the metal will begin to rub against the metal. In seconds, there will be tremendous friction, heat will be released, and the parts will jam or collapse. It is precisely to prevent this catastrophe that it exists. bearing It is an element that many have seen, but few have thought about its ingenious simplicity.

In simple terms, a bearing is a mechanical device that allows two parts to move relative to each other with minimal resistance. It takes on the load from the rotating shaft and transfers it to the body, allowing the shaft to spin almost freely. Without this little part, no car will go, no engine will start, and no turbine will start.

In today’s world, we are surrounded by machines that are used to ball-bearing Or its more sophisticated counterparts. From children’s toys to spaceships, smooth rotation is required everywhere. In this article, we will discuss how this part is made, why it is so important and how to understand that something is wrong with it.

Why do you need a bearing and what role does it play?

The main task of any support of rotation is to reduce friction. When two surfaces rub against each other, the energy of the motion is converted into heat and the material wears out. The bearing separates the moving parts, minimizing the contact area. Ideally, the friction of the slip is replaced by the friction of the rolling, which is several times less.

In addition, this element fixes the shaft in space. It does not allow it to move sideways or up and down, maintaining a strictly defined axis of rotation. This is critical for the accuracy of the mechanisms. If the shaft begins to “walk”, the vibration will quickly destroy the conjugated parts.

⚠️ Attention: Operation of the mechanism with a damaged bearing leads to rapid failure of the shaft and the landing place of the housing. Ignoring the hum can cost replacing the entire node, not just a cheap support.

The bearing also performs the function of load distribution. It perceives the weight of the rotating parts, the force of inertia during acceleration and braking, as well as vibration. The load It is transmitted to the machine body or machine, remaining localized at the installation point.

The device and the principle of operation: what it consists of

Classical. ball-bearing It consists of four main elements. These are two rings (internal and external), which have special grooves - rolling paths. Between these rings are the bodies of rolling: balls or rollers. To avoid them lumping together, they are separated by a separator.

The principle of operation is based on the physics of rolling. When the inner ring begins to rotate with the shaft, the balls roll along the tracks of the outer ring. The sliding friction is almost absent here. The separator is usually made of brass, steel or durable plastic and serves to distribute the rolling bodies evenly.

To protect against dust, dirt and moisture, as well as to keep lubricant inside, are often used sealing or caps. They can be rubber or metal. The presence of lubricant is a critical factor of durability, since it creates a thin film that excludes direct contact of metal even with microscopic deformations.

The main types of bearings and their features

The world of bearings is huge, and each design is made for its own conditions. Balloons. The models are most common due to their versatility. They tolerate radial loads and moderate axial loads well. However, for heavy loads they can be weak.

• 🛠️ Ball radial: The most popular, used in electric motors, wheels of cars and household appliances.
• 🛠️ Roller: Instead of balloons, there are cylinders, which increases the contact area and allows you to withstand huge weights.
• 🛠️ Conical: created for the perception of combined loads, often found in the hubs of cars.
• 🛠️ Spherical: They are able to compensate for the distortions of the shaft, which is important when assembling nodes imperfectly.

It is worth mentioning separately. slip-bearing. They don't have balls or rollers. The shaft rotates inside the sleeve, and friction is reduced by a layer of lubricant or a special antifriction material (for example, graphite or bronze). They are quieter and cheaper, but have large friction losses at start.

Manufacture materials and quality requirements

To withstand tremendous pressures and speeds, materials must have exceptional strength. Specialty is most often used. bearing-steel (e.g. stamp SHX15). It undergoes heat treatment, becoming very hard, but not losing its viscosity.

In aggressive environments or at high temperatures, steel is replaced with ceramics or special alloys. Ceramic balls are lightweight, do not rust and can withstand heating to 800 degrees, but they are fragile when impacted. Plastics Separators and housings are used where lightness and absence of corrosion are important.

Precision manufacturing is another key parameter. The roughness of the surface of the rolling tracks is measured in fractions of a micron. Any grain of sand or burrs will turn into an abrasive that will quickly break the knot. Therefore, assembly often occurs under sterile conditions.

Lubrication: the life of the bearing depends on it

The lubricant in the bearing performs a triple function: reduces friction, removes heat and protects against corrosion. Without it, the metal will catch in a fraction of a second. There are two main types of lubrication: plastic lubricants (consistent) and liquid oils.

Plastic lubricants, popularly known as litol or solidol, are put inside during manufacturing or maintenance. They do not leak and create a reliable barrier to dirt. Oil It is also used in forced circulation systems where intensive cooling is required, such as an internal combustion engine.

⚠️ Warning: Never mix different types of lubricants (e.g., lithium and calcium). A chemical reaction can lead to the breakdown of the lubricant structure, its leakage and instant jamming of the node.

Modern bearings are often produced with labeling. 2RS or ZZThis means that there are built-in seals and already laid lubricant for the entire service life. They do not need and often cannot be re-lubricated – they simply change to new ones.

Diagnostics of malfunctions: how to know that it is worn out

To determine the malfunction of the support of rotation can be by characteristic signs. The most obvious is noise. A hum, howl or crunch that increases with increasing rotation speed directly indicates a problem. In the car, it is often heard as a monotonous hum, changing the tone on the corners.

The second sign is heat. If after work the knot is hot to touch with your hand (temperature above 70-80 degrees), then the lubricant has dried or the rolling geometry has been broken. The third sign is a backlash. If you shake the shaft with your hand and you feel a beating, then the rolling paths are destroyed.

Sometimes the cause of the noise is not the bearing itself, but an improper landing or distortion. Therefore, before replacing it is necessary to make sure that the shaft and the hole of the body do not have production. Installing a new part on a worn bed will not give results.

Frequent errors in replacement and operation

Many consider replacing the bearing to be a simple matter: knocked out the old, pressed the new. But there are a lot of nuances here. The main mistake is hitting the rings directly with a hammer. This leaves dents on the rolling tracks, and the new bearing will sound in a couple of kilometers.

Pressure or score should only be in the ring that has a tight fit. If there is an inner ring on the shaft, we apply an effort to it. If the body is sitting outside - press on the outside. The transmission of force through the rolling bodies (balls) instantly disables them.

Another mistake is to ignore cleanliness. The entry of even microscopic metal shavings into the node is fatal. All work should be done on a clean surface, and hands and tools should be washed.

⚠️ Note: When pressing, be sure to use mandrels or special removers. Direct sledgehammer strikes on the shaft can damage not only the bearing, but also the shaft itself or the gearbox body.

Frequently Asked Questions (FAQ)