Daily maintenance of bearings

When the roller bearing is in operation, the stick performs a pure turning motion on the inner and outer ring raceways, so the support frame that drives the roller must have sufficient drag force to overcome frictional resistance. If the drag force is not enough to overcome the friction resistance, the roller will roll on the dovetail guide rail, causing a speed difference, that is, deviation. So what should you do if your roller bearings are misaligned? Below I will provide you with these common tricks to solve and prevent roller bearing misalignment.

Roller bearing

1. Reduce the number of rollers and reduce the roller diameter

The roller is held by the rotating ring. When the strength allows, its weight can be reduced to achieve the purpose of reducing inertial resistance. It becomes very important to avoid and reduce scrolling. This strategy is relatively simple, just reduce its number and diameter. In airline turbines, due to the small external load, contact fatigue is no longer the main damage factor of the rollers. According to the basic standard, the bearing size margin may be large. It is generally believed that the number of rollers is reduced by 50%, and after the diameter is reduced by 25%, its contact fatigue life will not be affected. Many automobile engines have adopted this strategy. For example, the main bearing of the Spey engine is of this type. Not only are the rollers obviously rare, but they are also of exquisite size.

2. Choose an effective structure and reduce cage weight

In addition to minimizing its weight when the strength allows, the cage should also consider its own characteristics, such as resonance, high-speed running resistance, etc. should be avoided.

The correct guide method of the cage is also a very critical factor in fast bearings. If the cage's unevenness is properly controlled, changing the cage from external guidance to internal guidance is also very helpful in reducing deviation. Due to the relative speed between the outer guide, the cage and the guide surface of the bearing, the lubricant and floating oil produce a viscous friction resistance, while the inner guide is conversely, the viscosity of the lubricant and floating oil between the cage and the guide surface The force becomes the drag force. In this way, the viscous frictional resistance becomes a force dragging the cage to rotate. The difference between the two cannot be ignored.

3. The oil provided under the ring

The advantage of using the oil provided under the ring is that it takes away the heat of the bearing and at the same time minimizes the additional damage caused by mixing. Another example is changing the outer ring with ribs to the inner ring with ribs, which will undoubtedly reduce the frictional resistance of mixing.

4. Use hollow roller preload bearings

Hollow roller preload bearings can add preload to all rollers so that there is no rolling in all areas. Since turbine rotor bearings operate in a wide range of speeds and temperatures, the appropriate preload should be selected carefully. Even at very low additional loads, excessive preload will cause premature roller failure. A common form of destruction is bending and fatigue. For a typical hollow roller, the ratio of diameter to inner diameter is 2, and the hole stress should be less than 25,000 pounds/foot; the coaxiality of the inner and outer diameters should be maintained at 0.005mm.