Super-precision bearings may be in every corner around you

Time：2020.03.06  Source：Roller Bearings Suppliers

In modern life, everyone can't do without all kinds of convenient transportation. Although everyone is familiar with trains, airplanes, etc., they may not know much about bearings, which are some of the essential parts that support their operation. In fact, in a country's economy, bearings are called "industrial joints." Rolling bearings are a must-have in the defense industry.

Fingertip gyro is undoubtedly the hottest little toy that will be popular in 2020. It is even regarded as a cure for ADHD, anxiety, and autism. A fingertip gyro is a small toy with a symmetrical structure that can rotate on the fingers. It consists of a bi-directional or multi-directional balanced body as the main body, and a bearing design is embedded in the middle of the main body to form a plane rotation. The basic principle of this new type of object is similar to the traditional gyro, but it needs to be grasped and flicked with a few fingers to make it rotate. The spinning inertia makes the top spinning at the fingertips, providing exceptional, unprecedented pleasure. You can't describe that feeling, as if it can rotate to take you to heaven.

Then when you are spinning your fingertip gyro, or when you are riding a bicycle through the streets of the city; when you are traveling by train and indulging in the famous mountains and rivers; when you are flying in a jet plane and flying in the blue sky, you Have you ever thought about whether your fingertip gyro, bicycle, train, or plane can go smoothly?

It all benefits from one of the greatest inventions in human history: the bearing.

Bearings exist in almost every corner of our lives: from bicycles or cars everywhere to civil airliners in the sky, from nuclear submarines in the deep sea to distant space stations, to refrigerators, washing machines, computer cooling fans, Range hoods, vibration motors in mobile phones.In short, bearings are everywhere. And with the development of technology, bearings are becoming more and more precise!

Precision bearings are classified according to the ISO classification standards: P0, P6, P5, P4, P2. Grades are increased in order, where P0 is ordinary precision, and other classes are precision grades. Of course, different grading standards and various types of bearings have different grading methods, but the meaning is the same. Precision bearings are also the most common precision ball bearings and precision roller bearings. It is a precision bearing that requires high rotation accuracy of the rotating body, high-speed rotation, and low friction and friction changes. Super-precision bearings are often used in many fields such as watches, aviation, medical, and micro-robots. Super-precision bearings can appear anywhere around you.

Precision bearings are also the most common precision ball bearings and precision roller bearings. Since the precision of the precision bearing is within one μm, it is required to have high dimensional accuracy, and shape accuracy with the matching parts (shaft, bearing housing, end cover, retaining ring, etc.), especially the accuracy of the mating surface should be controlled to be the same as that of the bearing At the level, this is crucial and most easily overlooked. It should also be noted that if the matching parts of the precision bearing fail to meet the above requirements, the precision bearing will often have an error several times larger than the original bearing after installation, or even a mistake of more than ten times, which cannot be called a precision bearing at all. It is that the error of the matching parts is not merely superimposed on the failure of the bearing, but is added after being amplified by different multiples.

For some super-precision bearings, the configuration requirements are also very high, regarding the configuration of precision bearings.

The traditional application field of precision bearings is the machine tool spindle. Depending on the process, the machine tool spindle has different requirements. In general, lathe spindles are used to cut metal at lower speeds and higher cutting loads. This type of axle usually transmits drive torque via a pulley or gear. This means that the load on the drive end of the spindle is also considerable.

The speed requirements of such applications are not too high. The more critical parameters are stiffness and load-carrying capacity. A prevalent method is to install a row of cylindrical roller bearings and a double-row angular contact thrust ball bearing at the working end of the spindle while using a double-row cylindrical roller bearing at the driving purpose of the rod. This configuration ensures long working life and excellent rigidity, resulting in high-quality parts. Moreover, from a kinematic point of view, the bearings can work stably, because the two types of bearings (radial and axial) respectively carry the load applied to the main shaft (in fact, to prevent angular contact thrust ball bearing diameter To the amount, the foreign outer diameter has individual tolerances to ensure that it will never touch the bearing seat).

When designing these types of spindles (this usually applies when the load is heavy), a rule of thumb about where the bearing is located on the shaft is that the distance between the centers of the front and rear supports is 3-3.5 times the bearing inner diameter. When higher speeds are required ( high-speed machining centers or internal grinding), different bearing solutions need to be found. It is clear that in these cases, a little sacrifice is required in terms of stiffness and load-carrying capacity. High-speed applications often use a directly driven spindle (known as a motorized spindle) with a direct-coupled motor and a coupling.