In a world of optimization and digitization where factories are trying to reduce costs and downtime, the demand for identification of basic gearbox failures can help save money and time. I-MAK has almost 50+ years in the design, development, production and service of gearboxes and power transmission solutions. This experience has helped I-MAK produce over a million possible product configurations in thousands of applications. Therefore, the company is quite proficient in identifying some of the key causes of gearbox failure and providing solutions. The following article examines three possible gearbox challenges.
Alignment of the gearbox on the application
This first cause of gearbox failure is purely mechanical, gears being designed to work in a certain configuration and backlash settings for each gear tooth, that when misaligned can cause a concentration of loads on a part of the gear, housing, bearings or other weaker part of the gearbox and induce premature failure. The identification of misalignment can be done during the maintenance period throughout the lifetime of the gearbox. Before failure, the healthier way to process is to ensure the right mounting of the gearbox during the installation in a new application or after the servicing of some of the machine’s components. I-MAK engineers also advise control of the gearbox alignment with regular visits with end users to secure early identification or future gearbox failures.
When a major customer in Belgium called I-MAK for high noise and vibration on an IRKM bevel geared motor, the company immediately sent the closest service team. The team quickly noticed a misalignment of the output shaft and harsh working conditions. The geared motors were set to work on an elevator at a height of 25 meters, not protected from dust, rain and salty mist, therefore, the gearbox was in high risk. After securing the installation with two mobile cranes, the servicing team removed the gearbox, changed the seals, and output bearings. They installed a dust protection cover and proceeded to the final mounting and alignment of the gearbox. The geared motors are now smoothly running and protected from any external aggressions.
Lubrication of the gearbox
Most of I-MAK’s gearboxes are supplied with high quality lubricant oil adapted to the type of application, environment, and mounting configuration. As the manufacturer, I-MAK calculates the right quantity and defines the right type of oil to ensure an ideal lubrication for both gears and bearings. The bath and splash lubrication configurations allow the right spread of oil in the gearbox, allowing the oil to create a thin film on the gears. This thin layer of oil prevents a metal to metal contact between the gears during their engagement. During the gearbox lifetime the oil quantity and quality can change depending on the applications and regular service intervals. Sealed and protected from external pollutants is a good method to ensure the health of the gearbox, a yearly oil change is recommended to allow for optimal lubrication. During the oil drain a quick analysis of the oil quantity, color, presence of external elements, can give key indicators of the gearbox health. Gearboxes working in harsh condition can lose significant quantity of oil during their lifetime, causing a lack of lubrication of the primary gears and irreversible damages.
I-MAK is still receiving some feedback from customers regarding over or lack of lubrication. This is mainly due to some manufacturers that order the gearbox in standard position, in many cases the geared motors are installed in nonstandard mounting position, causing over or lack of lubrication as the standard quantity of oil is set to match the horizontal (P1) mounting position. In order to prevent such minor mistakes with potentially big consequences, I-MAK is attaching a manual guide to each gearbox and attaching special stickers concerning the oil quantities. End users can also access the right quantity of oil in a few clicks via the company’s online product configurator.
Overload and operating mistakes
Particularly active in mining and stone crushing sectors, I-MAK geared motors are often exposed to harsh working condition, the gearboxes also suffer from overload and operating mistakes. Gearboxes are initially supplied with the right configuration and service factor to offer optimal working and enhanced performance. Yet the working conditions at the end user facility can differ from day to day and sometimes become extreme for the gearboxes, in facilities like; water treatment plants, bulk material producer and recycling companies. These applications are often the ones imposing the hardest working conditions to the gearboxes. Exposed to external conditions these operators are regularly forced to stop their operation in emergency due to rain, electrical outages, feeder overloads etc.
During these emergency stop events, heavy loads are applied to the output shafts, torque arms and backstop devices. Fully loaded a conveyor, mixer or shredder is demanding an extra effort to the geared motors until it gets to the requested operating speed. Soft start devices and adapted automation can reduce the overload and mitigate the efforts made by the gearboxes. Unfortunately, it is hard to identity a damaged gearbox in such noisy environment. These gearboxes rarely shows noise or vibration until it is too late. At this stage, the operating temperature of the gearbox remains a good factor to identify potential failures that sometimes take years to appear.
Most of I-MAK’s service interventions happen in the water treatment sector, customers tend to under-evaluate their geared motors needs, this creates serious overload on the gearboxes and causes downtime for water treatments plans. Available 7 days/24 hours, the online servicing team helps to identify the problems and quickly sends a team. But I-MAK also developed a more proactive strategy with a special team of engineers dedicated to water treatment plants, directly working with machines producers and end users to select and identify the best geared motors for their installations.