Common Types of Gear Tooth Failures


Gears fail various ways, typically tooth scoring, pitting, breakage or fatigue. Assessing gear damage can be challenging, especially in industrial equipment. Often, there are several conditions simultaneously contributing towards the failure. It is important to understand the basics and avoid if possible. We can can categorize failures as follows: 


  • Breakage 
  • Wear 
  • Surface fatigue 
  • Plastic deformation  
  • Manufacturing and installation failures



Breakage is a fracture of the entire tooth or substantial part of it due to overload or repeated over-stressing of the tooth material. Fractures generally happen due to high bending stresses in the tooth root or fillet radius, sometimes emphasized by cracks or notches. 



Wear is a more or less gradual removal of the material from the contact surfaces of the meshing teeth. Factors that contributor to wear include load load, improper lubrication, abrasive particles, corrosion. 


Surface Fatigue

Also known as pitting, surface fatigue is a process of the removal of small pieces of metal, leaving cavities or pits on the surface. This is caused by repeated loads that produce stresses higher than the endurance limit of the material. It usually progresses over a long period of time. A severe form, in which large pits occur in considerable area is called spalling. 


Plastic Deformation

This happens when the stress is sufficient to permanently deform the metal. Heavy loads, in combination with the rolling and sliding action of mashing teeth causes the contact surfaces to yield and deform permanently. 


Manufacturing Failures                                    

This category includes such failure modes as grinding burns, tool marks or nicks, quenching marks cracks due to heat treatment. These defects can lead to catastrophic failures.


Failure analysis can be used to identify the cause of the failure. Material properties and characteristics can contribute to these failures. Some of the common ways that gears fail can be avoided by choosing the right material, proper processing, protection from contamination or simply making sure that gears are properly lubricated.


Feel free to Contact Us if you have any questions, need more information or if you are interested in purchasing an gear products. HVH is a power transmission distributor doing business in USA.


Visit: Gear Products  


HVH offers the following brands for open gearing products, enclosed gear drives and motor products

Boston GearRossiBauer Gear MotorDalton GearWorldWide ElectricDelroyd Worm Gear


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Vladimir Harutyunyan

Vladimir Harutyunyan is the founder of HVH Industrial. He has masters degree in mechanical engineering and over 10 years of experience in mechanical power transmission field. 

Feel free to connect with Vlad on Linkedin:


Vladimir Harutyunyan

Vladimir Harutyunyan is the founder of HVH Industrial ...

Feel free to connect with Vlad on Linkedin:

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