What is the principle of the heating of the sliding bearing

For sliding bearings, we should have seen them all. We all know that the shaft and the sliding bearing are a pair of friction pairs, which belong to sliding friction. Friction will generate heat, and its calorific value is proportional to the frictional force and the speed of movement; the greater the frictional force, the greater the heat, and the faster the speed, the more heat.

In order to avoid the friction between the shaft and the end of the spherical tile caused by the insensitivity of the spherical tile, some open the tile mouth to a large extent, although the problem is solved to a certain level, but in a sense, it actually increases the bearing unit. The force on the area will shorten the life of the bearing, and reduce the bearing's ability to resist risks. When there is trouble, the moving bearing will heat up, which is not conducive to stable operation.

This is a problem. In fact, the friction coefficient also increases with the increase of the pressure per unit area. Once the friction coefficient increases, the frictional heat will increase. Breakthrough, the bearing heats up.

In fact, when the pressure per unit area of ​​the sliding bearing increases, the friction coefficient increases rapidly. For details, please refer to the table below.

When the pressure of the sliding bearing increases, the friction coefficient increases. Since the friction work is equal to the product of the friction coefficient, the positive pressure and the motion speed, when the contact is poor, the contact area decreases and the pressure increases; the total load increases when the equipment vibrates. If the pressure is large, the pressure will increase, the friction coefficient will increase, the heat generation will increase, and the sliding bearing will definitely heat up.

Therefore, the contact accuracy of the sliding bearing is reduced under any condition, and the load under any condition is increased, which will lead to an increase in the partial pressure of the sliding bearing, thereby increasing the friction coefficient and causing the bearing to heat up.

The sliding bearing runs well before shutdown, but the tile is hot when starting up, or even partially burned, which is actually caused by the large friction force at startup. At this time, not only the friction force is large, but also the lubrication conditions cannot meet the requirements, especially without static pressure. booted device.

Then, on the other hand, such as braking, it is different. The friction coefficient increases from small to large. It is difficult to stop the equipment running at high speed instantly. Even if the sliding bearing has a holding brake, it is difficult to explain the high-speed train with the principle of inertia. Braking, in fact, the impact of friction coefficient is also there, at least prolong the parking time.

In some cases, in order to improve the sensitivity of the spherical surface of the sliding bearing, the contact area between the spherical surface and the seat is reduced to a very small extent, especially if there is a groove in the middle of the spherical surface, only the two sides of the groove are rarely partially contacted, and the friction force will be reduced. It is greatly increased, which is not conducive to the activities of spherical tiles.

Although the huge pressure did not form a crush, there will always be some high points pressed in, which is like rooting on both sides of the bridge, which increases the stability of the spherical tile. Therefore, in equipment management and maintenance, it is better to meet the design requirements as much as possible. For some parts with low machining accuracy, methods should be found to compensate by manual methods to make them meet the design requirements.

The friction coefficient of the sliding bearing is not only related to the pressure, but also to the speed of the movement. The following is the relationship between the speed and the friction coefficient.

When the sliding bearing equipment is started, the friction coefficient is very large. After running, the friction coefficient decreases, but the change is relatively small within a certain interval. The magnitude of the change is relatively different from the influence of pressure on the friction coefficient. The method of reducing the kiln speed is often used when heating. Although it is effective, most of them cannot change the fate of heating. This is the reason.

The sliding bearing friction force is proportional to the positive pressure and the friction coefficient. From the design point of view, the total load is determined. After the bearing diameter and length are determined, the pressure per unit area is also constant. These conditions are met during operation. The bearing will not heat up, but the operation changes. When the total load increases, the actual contact arc length and the actual contact length change, the pressure per unit area will increase.