1, wear failure

 

Wear failure is the failure caused by the relative sliding friction between surfaces, which results in the continuous wear of the metal on the working surface. IKO linear bearings and continuous wear will gradually damage the parts in linear bearings, and eventually lead to the loss of dimensional accuracy of linear bearings and other related problems. Wear will affect the shape change, increase the fit gap, change the shape of the working surface, and may affect the lubricant or make the lubricant contaminated to a certain extent, leading to complete loss of lubrication function, resulting in the loss of rotation accuracy of linear bearings, and even can not work normally.

 

Wear failure is one of the common failure modes of bearings. According to the wear form, it can be divided into common abrasive wear and adhesive wear.

 

Abrasive wear refers to the wear caused by the relative movement of foreign hard particles or hard foreign bodies or abrasive particles invading the metal surface between the working surface of linear bearings and the contact surface, which usually causes furrowed scratches on the working surface of bearings. Hard particles or foreign bodies may come from inside the host, or other adjacent components from the host system may be fed into the linear bearing through lubricating media.

 

Adhesive wear refers to the uneven stress on a frictional surface due to tiny bumps or foreign bodies on the frictional surface. When the lubrication condition deteriorates seriously, the local friction heat is easy to lead to the local deformation of the friction surface and friction micro-welding. In severe cases, the metal on the surface may locally melt, and the force on the contact surface can tear the local friction-welded joint away from the substrate and increase plastic deformation. This cycle of stick-rip-stick constitutes stick-wear. In general, slight adhesive wear is called abrasion and severe adhesive wear is called occlusion.

 

2. Contact fatigue failure

 

Contact fatigue failure refers to the failure caused by the alternating stress on the working surface of linear bearings. Contact fatigue spalling occurs on the working surface of linear bearings and is often accompanied by fatigue cracks. First, it occurs at alternating shear stresses below the contact surface, and then spreads to the surface to form different spalling shapes, such as pitting or pitting spalling, and spalling into small sheets called shallow spalling. Due to the gradual expansion of the exfoliated surface, it often extends into the deep layer and forms a deep exfoliation. Deep exfoliation is the fatigue source of contact fatigue failure.

 

3. Fracture failure

 

The main causes of fracture failure of linear bearings are defects and overload. When the applied load exceeds the strength limit of the material and causes the part to break, it is called overload fracture. The main cause of overload is a sudden failure or improper installation of the main engine. When impact overload or violent vibration occurs, such defects as micro cracks, shrinkage holes, bubbles, large foreign bodies, overheating tissue and local burns of bearing parts will also lead to the fracture of the defect, which is called defect fracture.

 

It should be pointed out that in the manufacturing process, linear bearings can correctly analyze the existence of the above defects through the reinspection of raw materials, the quality control of forging and heat treatment, and the instruments in the process control. In the future, it is necessary to strengthen the control. However, in general, the common failure of linear bearing fracture is overload failure. At present, linear bearings are more and more 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 measuring equipment.