Transmission Efficiency and Surface Damage of Polymer–Polymer Gear Pair Under Wet Lubrication

Abstract

Polyamide, with its low friction coefficient, high heat resistance and good moldability, is a promising polymer to meet the rising demand for lightweight, durable gears. This paper considered injection-molded polyamide 66-polyamide 66 gear pair wear performance under unlubricated and wet lubricated condition. The experiment was conducted using in-house developed power absorption gear test rig. The torque of 1.8 Nm, rotational speed 800 rev/s and lubricant SAE 75W85 was considered during testing. During the test, gear tooth temperature under unlubricated condition and lubricant temperature under wet lubricant condition was measured and monitored. The net surface temperature on the gear surface and lubricant was observed as 370 K and 303.4 K, respectively. The transmission efficiency was increased by 5% compared to the unlubricated condition. Testing confirmed that the gear exhibited surface wear at both the face and flank region in unlubricated condition. While testing under wet lubricant condition, the wear was observed on the face of the gear. Simulation result confirmed that the deflection of test gear is significantly higher in double tooth contact region shared by the face side as compared to flank side of the driven (test) gear. That could be the possible reason for test tooth wear in the face region.

Investigation on the effect of strain rate on standard involute and asymmetric polymer gears using the newly design fixture for single tooth testing method

“…Additionally, reinforcement such as glass/carbon fiber in gear materials has also been observed in gear performance investigation. [15][16][17] Whereas, in additive manufacturing process, due to limitation of reinforcement not many varieties of material have been used in polymer gears for its experimental investigation. PA618, PLA, ABS and nano clay ABS are only few materials which have been used so far for producing gears using additive manufacturing through FDM (Fused Deposition Modelling) method for gear pair performance investigation.…”

A review on materials and performance characteristics of polymer gears

“…Lubricated condition increases transmission efficiency by 5% as compared to unlubricated condition as can be seen for PA66 gear. 182 Due to having viscoelastic properties, variation in temperature, humidity and rotational speed makes a significant effect on meshing stiffness, transmission error, and load sharing. 124 In case when identical or similar material gear are used, TE reduces with increasing contact ratio and amplitude of TE considerably reduced by use of integer contact ratios.…”