Top 3 Causes of Gearbox Failures
Gearboxes are common rotating equipment found in many industries. A gearbox is an enclosed set of rotating gears working together in unison to generate rotating power. Though designed to be durable and capable of working on despite hindrances such as dirt, debris and other contaminants, gearboxes can still fail. There are three main reasons why gearboxes fail: poor lubrication, gear misalignment and gearbox overload.
Most often, gearboxes fail, sometimes catastrophically, due to a lack of lubrication of the gears within the housing. A properly lubricated gearbox is necessary because “The lubricating oil forms a thin film that prevents metal-to-metal contacts between the gears and within the bearing components.”1 Therefore, without proper lubrication, the gears themselves can become greatly damaged and result in serious damage if pieces of the gears themselves begin to chip away due to friction from the excessively close contact, unprotected by a layer of oil lubrication. For larger gearboxes used in industrial applications, generally speaking, it is highly advised to change the oil in the gearbox every 6 months, or 2500 hours2. It is also recommended to monitor the oil level of the gearbox daily by looking at the oil level in the sight glass, as well as consulting the user manual for the gearbox for the best practices regarding proper lubrication.
Though less frequent, gear misalignment is another potential cause of failure for gearboxes. Gear misalignments are major issues because “Even a small amount of misalignment can cause premature gear wear and failure. The gear teeth will not mesh the way they were designed to, resulting in excessive loads in the weaker parts of the teeth.”3 Most of the time, gear misalignments are due to improper installation and/or assessment of the gearbox. Gear misalignments can often be avoided by properly inspecting the gears within the housing before running the gearbox by a trained professional, as well as proper installation according to the installation and user manuals.
The third and final most frequent cause of gearbox failures is due to overloading the gearbox. In short, overloading is synonymous with working the gearbox beyond its intended loads. The best remedy of preventing gearbox overload is to determine exactly the recommended workload limits of the gearbox in question via the user manual, so as to prevent overloading of the gearbox.
Based on the three main causes of gearbox failures– lack of lubrication, gear misalignment and overloading– in general, these three can be easily prevented by utilizing articles such as the user manual, as well as consulting the manufacturer when serious inquiries arise.