Loss of Lubricant

Lubricants serve multiple critical roles in power transfer mechanisms such as gears and bearings. Two important functions are the reduction of friction between the mating surfaces and the reduction of heat buildup through absorption and transfer.

In a loss of lubricant or oil-out condition, these benefits are lost.  As heat builds in the power transfer system the components expand, reducing the clearances designed into the system (example – gear backlash).  This “tightening” of the mating components further increases friction, accelerating the rate of heat generation and pushing the system towards catastrophic failure.

REM’s isotopic superfinishing processes reduce surface roughness and impart an isotropic texture on a component’s surface such as a gear flank. This surface increases the effective film thickness (lambda ratio) and reduces friction while still benefiting from strong lubricant retention properties. Derivatively, an ISF® Surface will generate significantly less heat and will significantly extend component/system life during a loss of lubricant/oil-out event.

Multiple papers and studies document these and related facts including:

Some of the results discussed in these papers include:

  • SAE 9310 rolling/sliding contact fatigue testing with loss of lubrication simulation where:
    • Isotropically superfinished specimens survived 30 minutes at 400 ksi,(~2,760 Mpa)
    • Ground specimens failed after less than 1 minute at 400 ksi (~2,760 Mpa)
  • SAE 9310 spur gear scuffing testing where:
    • Isotropically superfinished spur gears withstood 60⁰ F (~15.5° C) increased lubricant supply temperature prior to scuffing as compared to ground spur gears
  • Bell M427 MRGB (AMS 6308 components) extreme condition testing where:
    • Low Oil Pressure testing at 550 hp (~410 kW) per input, 25-30 psig (~172 – 206 kPag) oil pressure and a maximum of 230⁰ F (110° C) oil temperature resulted in no scuffing or any visual signs of damage after 30 minutes of operation
    • High-Temperature testing at 550 hp (~410 kW) per input, 55 psig (~379 kPag) oil pressure and greater than 230⁰ F (110° C) oil temperature resulted in no scuffing or any visual signs of damage after 30 minutes of operation
  • AH-64D Engine Nose Gearbox (ENGB) loss of lubrication testing where:
    • The isotropically superfinished ENGB was operated at ~20,592 RPM and ~188 ft-lbs. (~255 Nm) input torque for 60 minutes in loss of lubrication conditions and experienced no failure; upon post-test inspection, no evidence of distress was found on the gear teeth or bearings

REM’s ISF and Rapid ISF Processes can be applied to a wide range of components types, sizes, and metals. These processing technologies are available via outsourced processing at a REM facility or as technology installations at a customer site. Contact us today to learn more or to start a project.