Gear Failure Reasons And Solutions
Ball mill is widely used in mineral ore grinding and cement production industry. But sometimes, in the production process, ball mill will halt because of the fault in reducer. And the fault in reducer is mainly because the failure of gear. So in this article, we mainly talk about reasons and solutions about gear failure in ball mill.
Gear Failure Reasons
There are several types about the gear failure in ball mill: damage of tooth surface, pitting of tooth surface, veneer of tooth surface, plastic deformation of tooth surface.
Damage of tooth surface: the damage of tooth surface is mainly because of friction produced by the relative sliding between two tooth surfaces. This belongs to normal wear.
Pitting of tooth surface: Since the gear works under heavy load, so theoretically, contact between the two gears is line contact. But because of the elastic deformation, their contact is surface contact with strong contact stress produced on the surface. The contact stress changes according to certain rules and when the stress reaches to a limit value, there will be fatigue cracks produced on the surface of gear.
Veneer of tooth surface: when the ball mill is over load or the lubricating oil in reducer is improper, which will lead to the rise of temperature of gear. Under heavy load, the oil film between the gear surface breaks, making the metal faces of two gears directly contact.
Plastic deformation of tooth surface: The plastic deformation of tooth surface is mainly because the hardness of gear surface is not high enough. Under heavy load, the surface metal will have local plastic deformation of tooth surface along with the direction of friction.
Gear Failure Solutions
For gear parts suddenly because of serious impact or overload, we should optimize the heat treatment process. We can adopt induced surface hardening instead of flame case hardening in order to make the case depth even and to reduce the deviation and fragility.
For gear parts because of fatigue, we should increase the root fillet while processing the tooth surface in order to reduce the stress concentration at the root. In this case, we not only can improve the finish of gear surface but also can reduce the producing of fatigue crack.