News | Tribology and Industrial Maintenance

Gearbox Test Rig

25 - 09 - 2018
In recent years environmental and sustainability issues have gained particular relevance. There has been an international effort to make a more efficient and effective use of the available resources. 

Gears and gearboxes are very common mechanical elements/mechanisms that can be found on a number of machines, from the small do-it-yourself tool to the transportation and wind industries. Therefore, let it be by their sheer number or magnitude of the transmitted power it is in the interest of all to maximize the longevity and efficiency of existing gear transmissions and to develop solutions where efficiency is as important as reliability. 

It should also be noted that a gear transmission designed with efficiency in mind promotes less heat generation in the contacting elements, resulting in a lower operating temperature which in turn reduces the likelihood of faults related to surface distress phenomena. A lower operating temperature also improves lubricant longevity, potentially increasing maintenance intervals.

In recent years, the Tribology, Vibrations and Industrial Maintenance team from INEGI has been investigating solutions to develop more efficient gear transmissions. In these studies not only the geometry of gears and rolling bearings but also the influence lubricant the lubricant formulation on the performance of gearboxes were investigated. 

The work developed in this field has resulted not only in several Master's and PhD theses but also in dozens of publications in international journals with scientific impact, being these works well received by industrial partners and the scientific community at international conferences on the subjects of gears and tribology.

INEGI has test rigs to individually study rolling bearings and gears. Then in order to validate the individual results and models resulting from those results, there is a test rig that allows simultaneous testing of two complete twin gearboxes.

The Gearbox Test Rig allows the study of several metrics related to the tribological performance of gear transmissions. If on the one hand, this test rig allows evaluating gearbox reliability, on the other hand, it also allows to carry out studies on efficiency, being able to even make a distinction in the performance level of different constructive solutions and also different lubricants. 

This test rig operates according to a recirculating power scheme such that the motor which drives it, only needs to provide the necessary (dissipated) energy to keep the system in rotation at the imposed operating speed. In Figure 1 the test rig is shown during a test to a transfer gearbox of a firefighting vehicle.

Figure 1: Test to a transfer gearbox of a firefighting vehicle.

During a test several parameters are monitored:

Test gearbox input and output speeds;
Test gearbox input and output torques;
Test Gearbox operating temperature in 3 different points;
Air temperature in the test room.

Figure 2 shows a detail of the tested transfer gearbox where an internal and an external temperature measurement points are shown. 

Figure 2: Detail of a tested transfer with the external and internal temperature measurement points.

The Gearbox Test Rig allows the following operating conditions:

Input speed of the test gearbox from 100 to 4000 rpm;
Input / Output torques of the test gearbox up to 1300/5650 Nm.