AGMA 98FTM10 PDF

The friction conditions in the mesh of worm gear drives have big influence on the efficiency of worm gears. Because the friction conditions of worm gears can't be determined directly, a special test rig (three disk test rig) was built to simulate the contact conditions for discrete points along the contact lines of a worm gear.

The highest values of the local coefficient of friction occur under poor lubricating conditions with the vector of the rolling speed in direction of the contact line, normally in the center of a worm gear flank, the lowest coefficients of friction in the area of the outlet.

Furtheron the local coefficients of friction strongly depend on the type of lubricant and material combination and to a minor extent on load, lubricant viscosity and oil temperature. The investigations at the three disk test rig offer a cost saving possibility to examine the different influences on the coefficient of friction of worm gears.