Comparative Fatigue Resistance of Fiber Reinforced Nylon 6 Gears

Abstract

The fatigue-life diagrams of injection-molded nylon 6 gears with different reinforcements are shown for various lubrication modes (dry, grease, splash oil lubrication) and for different meshing combinations (plastic/plastic and steel/plastic gears). Tests using a suitably designed back-to-back rig have been carried out, and the results compared with previous experiments, performed using unreinforced nylon 6 gears. 232 gears (70 in unreinforced and 162 in differently filled nylon) were tested. More than 700 · 106 cycles have been totalled. From test data, and from the “matrix” of the gear/pinion material combination, the capabilities of differently reinforced nylon 6 gears in terms of fatigue and wear resistance have been outlined. These capabilities are the basis for a proper material selection in plastic gear design.

Wear characteristics of injection-moulded unfilled and glass-filled nylon 6 spur gears

“…Schematic representations of uniform wear and non-uniform wear on the gear teeth surfaces are shown in Figs 5b and d. Excessive wear of polymer gear on the dedendum region was also reported by Crippa and Davoli [15] and Tsukamoto [5].…”

“…The contact fatigue endurance limit strength of polymer materials is related to the strength and hardness of the material and is evaluated using rolling contact or gear or bearing tests [17,19]. For the different polymer and polymer composite materials the contact fatigue endurance limit strength varies between 0.6 and 0.8 times the tensile strength of the material [8,9,15,20,21].…”

Effect of rotational speed on the performance of unreinforced and glass fiber reinforced Nylon 6 spur gears

“…Short fiber reinforced polymers permit fabrication of complex shaped products economically using injection-molding process. Many research works have been performed on the issues related to the performance of polymer and polymer composite gears [1][2][3][4][5][6][7][8][9]. In those articles influence of reinforcement on the fatigue performance and wear resistance of polymer gears is well discussed.…”

Quasi-static Load Sharing Model in the Case of Moulded Glass Fibre Reinforced Polyamide 6 Gears

“…However they have a poor heat resistance and are limited to rotation transmission. In order to improve the gears performance, glass fibre is being increasingly used, where their lower cost and higher strength, compared to unreinforced polyamide, offers a potential increase in gear performance [1,2]. For those reasons, moulded glass fibre reinforced polyamide becomes the most common reinforced gear material.…”