Sizes range from 2 mm to 6 m
Bearings vary in size from small to large. The smallest “miniature bearing” in the world is 0.6 mm in inner diameter, 2.0 mm in outer diameter and 0.8 mm in thickness. Large bearings, with an outer diameter of 6 meters and a weight of more than 15 tons, are used in large shield machines for tunneling. This type of shield machine was used in the excavation of a cross sea tunnel under the Dover Strait, which connects Britain and France, and this large bearing was used.
Dental drill (commonly known as dental handpiece) is equipped with a bearing that can rotate at a super high speed. These are two ultra precision bearings with inner diameter of 3.0 mm × outer diameter of 6.0 mm × width of 2 mm and steel ball diameter of 1.0 mm. They can rotate at an amazing speed of “400000 revolutions per minute”, which greatly reduces the vibration of dental handpieces and greatly reduces the pain of patients during treatment.
The speed of steel ball is 160 meters per second
The main shaft bearing used in the V2500 jet engine of international airliner has a rolling speed of 160 meters per second, equivalent to 580 kilometers per hour. It is because of the use of high-performance and high-speed bearings that the engine can run safely for a long time and transport passengers safely to all parts of the world.
Amplitude below 100 nm
It is no exaggeration that “the accuracy of the machine depends on the rotation accuracy of the bearing”. The two ends of the rotating shaft are supported by two bearings. If the shaking of the axis is large, the mechanical performance cannot be improved. Wechat of metal processing has good content and deserves attention. The “hard disk”, a computer external storage device with ultra precision bearings, has an axial amplitude of less than 100 nm (1 nm = 1 / 1000000 mm). The key to achieve such ultra-high precision is the accuracy of rolling elements such as “steel ball” and “roller”.
Working in space for 15 years
The development of the universe is inseparable from bearings. Weather forecast, satellite radio and television signals, automobile satellite positioning information, etc., are provided by satellites flying around the earth. The satellite is equipped with a gyroscope to maintain the attitude and course of the satellite, and the gyroscope is equipped with ultra precision bearings. This kind of bearing can work continuously in space for 15 years.
A world of 253 degrees below zero to 500 degrees above zero
The bearings in the liquid fuel pump of space rocket are the bearings with the lowest temperature. The bearing operates in liquid hydrogen at minus 253 ℃. The special high performance bearing used in medical CT scanner is the typical representative of the bearing used in high temperature environment. In X-ray vacuum tubes with temperatures up to 300 to 500 ℃, the bearings can also operate continuously to protect our health.