What is the cause of gear damage

The main causes of gear damage can be roughly divided into: wear; pitting, peeling, carburizing layer fragmentation; fatigue; impact; corrugation, arris and cold deformation. Most gear damage is due to excessive gear load, or shock or shock loads caused by incorrect shifting or clutch operation. If there is a defect in a gear, it can only be determined by metallographic examination.

Wear is the removal of surface material from gears. It can be slow, like a scratch, or quick, like a scratch. There are three types of wear:

Adhesive wear is caused by metal to metal contact, and the surface is bonded together and then torn off. It may be due to insufficient lubricating oil or improper gear engagement.

Abrasive wear is caused by external particles such as dust and sand.

The chemical attack on the surface of gears caused by contaminated lubricating oil or additives.

Pitting, peeling off and cracking of carburized layer are fatigue defects, which appear when there are small particles on the gear falling off from the tooth surface. When the surfaces of meshing gears are in contact, the repeated stresses on these surfaces can cause pockmarks. They start along the contact line, which is the place with the largest pressure on the teeth of the mating parts, generally due to the excessive load. Fatigue cracks often start in the pockmarked area. Spalling is a serious form of further development of pockmarks, and a part of the gear may crack. The fracture of carburized layer is usually the crack along the tooth surface. It is often caused by excessive working load.

Fatigue fatigue is usually caused by repeated and excessive load, which is often broken at or near the root of gear. Fatigue defects may start from small cracks caused by extremely high load, and continue to develop under normal use until gear failure.