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.

Issue Section:
Research Papers
Topics:
Fatigue, Fibers, Gears, Nylon fabrics, Lubrication, Plastic gears, Cycles, Design, Fatigue life, Steel, Wear resistance
1.
Davoli, P., 1987, “La Resistenza Degli Ingranaggi in Plastica: Apparato di Prova e Prime Sperimentazioni,” (Plastic Gear Resistance: Test Apparatus), Organi di Trasmissione, October, pp. 134–138.
2.
Crippa, G., and Davoli, P., 1989, “Fatigue Resistance of Nylon 6 Gears,” Proceedings ASME 5th International Power Transmission and Gearing Conference, Chicago, pp. 229–234 (also in “Kunststoffe-German Plastics,” 2/91, pp. 147–150).
3.
Tsukamoto
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,
Maruyama
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, and
Ikuta
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,
1991
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Development of Low-Noise Gears
,”
JSME International Journal
, Vol.
34
, No.
2
, pp.
245
–
251
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4.
Tsukamoto
N.
, and
Maruyama
H.
,
1991
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A Study for the Development of Plastic Worm Gears (Plastic Worm Gears Filled with Fiber and Solid Lubricant)
,”
JSME International Journal
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34
, No.
2
, pp.
260
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264
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5.
Holman, J. P., 1989, Experimental Methods for Engineers, 5th edition, McGraw-Hill, New York, pp. 75–78.
6.
Du Pont, 1974, Zytel Nylon Resins Design Handbook, A-97932, June.
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