Pressure Measurement of Ambient Air in the Root Space of Helical Gears for the Purpose of Understanding Fluid Flow to Improve Lubrication Efficiency

Lubricant supply in gearing gives excess power loss due to churning as well as lubrication system. Since the behavior of lubricant at the mesh region is still unclear, much greater amount of oil than required is used for cooling because most part is thrown away by centrifugal force. For lower loss due to lubrication, it is necessary to discover the location of supplying nozzle. Authors have measured the pressure variation during the mesh process, which will give us an idea how we can deliver the lubricant properly with minimal but efficient cooling. Pressure measurement was done for several pairs of helical gears, that had a pressure gage installed at the bottom of root space. A sucking action is found to distribute along the tooth width especially at the recess side of meshing. Although there is global axial flow due to helix angle, which is directed from the leading side towards the trailing side, there is the opposite flow at a part at the trailing side.