NTN bearing failure reason analysis and considerations - bearing knowledge

1, contact fatigue failure of contact fatigue failure refers to the NTN bearing working surface under the role of alternating stress and failure. Contact fatigue spalling occurred in NTN bearing working surface, often accompanied by fatigue crack, first of all, from the maximum cyclic shear stress under contact surface, and then extended to form a different flake shape, such as dot to pitting corrosion or pitting spalling, peel into small sheet according to the shallow flaking. Due to spalling surface expands gradually, and often to deep extension, forming deep spalling. Deep spalling is contact fatigue failure of fatigue source. 2, wear failure wear failure refers to the relative sliding friction between the surface of lead to constant wear and tear of the working surface of metal. Continuous wear will cause NTN bearing parts damaged, gradually and eventually result in the loss NTN bearing dimensional accuracy and other related issues. Wear may affect the shape change, the increase of fit clearance and working surface morphology change, may affect the lubricant or make its pollution to a certain degree of lubrication function is lost, so that loss of NTN bearing rotating accuracy and will not operate properly. Wear failure is one of the common failure modes of all kinds of bearings, according to the wear and tear is usually divided into one of the most common form of abrasive wear and adhesive wear. Between abrasive wear refers to the NTN bearing working surface into the external hard hard foreign body or abrasive dust on the surface of the metal particles or relative movement and the contact surface caused by wear and tear, often cause furrow of abrasion in bearings working surface. Hard particles or other foreign body may come from inside the host, or from the host system adjacent parts by lubricating medium to the NTN bearing inside. NTN bearing accuracy of relevant knowledge. Adhesive wear refers to the because of the friction surface microscopic bumps or foreign bodies make the friction surface is uneven, serious deterioration, the condition of lubrication for local friction heat production, easy to cause local deformation and friction surface friction welded phenomenon, serious when the surface of the metal may be the partial melting, contact surface forces from the local friction welding points on the matrix will be torn and increase the plastic deformation. This kind of adhesive - — Tear - — Adhesive cycle constitutes the adhesive wear and tear, in general, mild adhesive wear is called a scratch, serious adhesive wear called occlusion. 3, fracture failure NTN bearing failure of the main reason is that defects and overload two factors. When the loads more than material strength limit fracture caused by parts called overload fracture. Overload reason mainly is the main engine failure or improper installation. Bearing parts of micro crack, shrinkage cavity, bubbles and large foreign impurities, overheating organizations and local burns and other defects during the impact overload or violent vibration will cause fracture in defect, known as defect fracture. It should be pointed out that NTN bearing in the process of manufacturing, for raw materials into the factory reinspection, forging and heat treatment quality control, process control through instrument analysis of the existence of the above defects and correct still must strengthen control in the future. But in general, most usually appear NTN bearing fracture failure for overload failure. 4, NTN bearing clearance change failure at work, because of the influence of the external or internal factors, change the original fit clearance, lower accuracy, and the change of 'killed' called clearance failure. , large amount of the external factors such as interference of installation does not reach the designated position, temperature rise caused by the expansion, instantaneous overload, etc. , internal factors such as residual austenite and the residual stress in a state of flux and so on all is the main reason for the failure caused by clearance changes. 1. NTN bearing if get good lubrication, and cut off the right moisture and debris, said oil seal should not wear. However, best when open the bearing box, check the bearing and periodically check the oil seal. Check of the condition of the near the bearing oil seal, in order to ensure that they are enough to prevent hot liquid along the axis of infiltration or corrosive liquid or gas bearing, oil seal if already wear should be replaced as soon as possible. 2. High temperature often said NTN bearing is in abnormal situation. High temperature also harmful to within the bearing lubricant. Sometimes could be blamed on the NTN bearing overheating bearing lubricant. If the bearing in the long run of more than 125 degrees Celsius temperature, reduces NTN bearing life. The causes of high temperature NTN bearing include: insufficient lubrication or excessive lubrication, lubricants containing magazine, the load is too large, NTN bearing damage, clearance, and the oil seal of high temperature and friction and so on. 3. Check the status of the operation of the machine, monitoring, lest cause the equipment downtime.