How to understand the fatigue and fracture issues of linear bearings

How to understand the fatigue and fracture issues of linear bearings

Linear bearings are increasingly widely used in equipment or special machinery industries, such as electronic equipment, food machinery, packaging machinery, medical machinery, printing machinery, textile machinery, machinery, instruments, robots, tool machinery, CNC machine tools, automobiles, and digital three-dimensional coordinate measurement equipment. Linear bearings have low frictional resistance, high accuracy, and fast movement speed during operation. Linear bearings are often in motion and may experience contact fatigue or even fracture problems.

Contact fatigue is caused by alternating stresses on the working surface of linear bearings. Contact fatigue peeling occurs on the working surface of linear bearings, often accompanied by fatigue cracks.

The contact fatigue of linear bearings occurs at the alternating shear stress below the contact surface, which then spreads to the surface, forming different peeling shapes, such as pitting or pitting peeling, peeling into small pieces, known as shallow peeling. Due to the gradual expansion of the peeling surface, it often extends to deeper layers and forms deep peeling.

The main reasons for the fracture of linear bearings are defects and overload. When the applied load exceeds the strength limit of the material and causes the part to fracture, it is called overload fracture. The main cause of overload is sudden failure or improper installation of the host. When impact overload or severe vibration occurs, defects such as microcracks, shrinkage holes, bubbles, large foreign objects, overheated tissues, and local burns of bearing parts can also cause fracture at the defect site, which is called defect fracture.

In the manufacturing process, linear bearings can be correctly analyzed for the existence of the above-mentioned defects through quality control of raw material retesting, forging and heat treatment, as well as instruments in process control.

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