Analysis of the Causes of Gear Surface Wear

- Jan 14, 2021-

During the meshing process of the gears of the gear reducer, material friction damage often occurs on the contact surface of the gear teeth. Where the amount of wear does not affect the function of the gear in the expected life, it is called normal wear. The normal wear of gears is characterized by bright and smooth tooth surfaces, no macro scratches, and tolerances within the allowable range. If the gear material is improperly used, or there are hard particles between the contact surfaces, and the supply of lubricating oil is insufficient or unclean, it will often cause early wear of the gear, and the separation of tiny particles will cause the contact surface to change in size and lose weight. And the tooth profile changes, the tooth thickness becomes thinner, and the noise increases. The result of severe wear will cause the gear to fail.    Wear failure forms can be divided into: abrasive wear, corrosive wear and impact wear on gear end faces.   

1. Gear abrasive wear   

In the process of gear slamming, if the supply of lubricating oil is insufficient or there are foreign tiny piles on the working tooth surface, severe abrasive wear will occur on the surface. The tooth surface of the gear is worn by abrasive particles, and there are fine and uniform streaks along the slide direction, and the tooth surface is dark. As a result of the further development of abrasive wear, the tooth profile will change, the tooth thickness will become thinner, and even “blade”-shaped tooth tips will appear, the clear contact gap will increase, the noise during transmission will increase, and sometimes the tooth thickness may be too thin to cause breakage tooth.  

2. Corrosion and wear   

Corrosive wear is a form of damage that is dominated by chemical corrosion and accompanied by mechanical wear. The macroscopic characteristics of chemically corroded wear gears are often corroded pits, and uniform and fine wear scars appear along the sliding speed direction on the working white surface. The abrasion products are all reddish-brown flakes, the main component of which is iron trioxide. Chemical corrosion wear is caused by the presence of city dyes or impurities in the lubricant and chemical or electrochemical reactions with the gear material. At the same time, the corrosion part falls off due to the friction of the gnawing and the erosion of the lubricant, forming chemical corrosion wear.   3. Impact wear of gear tooth end face   

Gear wheel tooth end face impact wear is when the gearbox gear is shifted, the wheel window end face is often subjected to impact load, which causes the tooth end face wear. If the gear surface hardness is too low, the tooth end face is easy to wear or rough; if the hardened layer is too shallow, it is easy to be crushed to expose the soft tissue of the heart; the hardness of the gear core is too high or the carbide level in the metallographic structure is too poor, Then the tip corners of the teeth are prone to chipping.