Lubrication in gearboxes

SPH simulation of oil/grease flows in gearboxes

SPH: Smoothed Particle Hydrodynamics

Particularly in classic areas of mechanical engineering, a significant boost in innovation can be achieved through the targeted use of simulation methods. Particularly in the field of gearboxes, complex experimental investigations are still very often carried out today to determine the distribution of lubricants.

In most cases, partially glazed gear housings are used and the lubricant distribution is evaluated by camera-based evaluation. However, this results in ambiguous flow conditions or flow conditions that are difficult to interpret, especially at high circumferential speeds of the gears. Furthermore, these tests must be repeated for different installation positions.

With the help of simulations using the SPH method, these tests can be carried out digitally. In contrast to CFD (Computational Fluid Dynamics), the SPH method offers the decisive advantage that no meshing of the system is required. SPH simulations thus calculate extremely quickly and can therefore be integrated very easily into in-house development processes.

Oil movement in the housing of a spur gear with 29.3 million
SPH particles

Velocity distribution of the oil during operation

What are the benefits?

In contrast to the trial-based investigation of oil flows in gearboxes, simulation offers the following advantages, among others:

  • clear evaluation of the lubrication of bearings
  • targeted determination of the necessary oil quantity for operational reliability
  • no costly production of glassed gearbox housings necessary
  • significant reduction of development costs
  • shorter development times and thus shorter time to market
  • targeted analysis of heat flows and local oil pressures in the gearbox
  • fast evaluation of design adaptations
  • build-up of flow knowledge with every simulation
  • independent of scheduling limitiations

In addition to the above-mentioned advantages, the behavior of the lubricant can be made visible by simulating its movement, thus enabling a rapid transfer of knowledge. It is thus possible to secure the operational know-how in a sustainable and tangible way.

Further applications

In addition to the movement of oils, greases can also be simulated. Here, different viscosities can be simulated in order to investigate, among other things, the homogeneity of the lubrication with varying insertion positions.

An analysis using the SPH method can save significant development time, especially for gears that are difficult to analyze, such as the worm gear shown here.

The worm gear shown here is based on a CAVEX® planetary from CAVEX GmbH & Co. KG

Grease distribution in a worm gear, based on a CAVEX® planetary