| 1. |
- Li, Xinmin, et al.
(författare)
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A Pin-on-Disk Study of the Tribological Properties of Polyoxymethylene (POM) Gear Materials
- 2024
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 73
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Tidskriftsartikel (refereegranskat)abstract
- Polyoxymethylene (POM) is now widely used as a gear material due to its excellent mechanical properties. There have been several studies on the tribology of POM; however, most of them focused solely on the material itself without integrating practical applications. This study investigates the tribological properties of POM-POM combinations in conjunction with the application of POM gears. Using a pin-on-disk machine, we simulate the sliding part of gear meshing. The influences of contact pressures (40 and 50 MPa), sliding speed (0.1 and 0.5 m/s), and lubrication on the tribological performance of POM pin sliding against POM disk were studied. The results showed that grease can reduce adhesion between sliding surfaces and effectively improve the tribological performance of the POM-POM combination. The friction coefficient decreases with increasing contact pressure, which is consistent with the existing models of the frictional behavior of polymer-polymer systems. The wear coefficient exhibits contrasting relationships with increasing contact pressure at high and low velocities. Because the wear mechanism changes from predominantly abrasion at low velocity to adhesion-peeling off at high velocity. Both the friction and wear coefficients decrease with increasing sliding velocity. The specific mechanisms of the influence of different lubrication conditions, pressures, velocities, and PV values on friction and wear are described and discussed throughout this article.
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| 2. |
- Wu, Yonglong, et al.
(författare)
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Effect of Humidity on the Tribological Properties of PA66 Gear Materials
- 2024
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Ingår i: Tribology letters. - : Springer Nature. - 1023-8883 .- 1573-2711. ; 72:3
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Tidskriftsartikel (refereegranskat)abstract
- PA66 is a commonly used material for plastic gears due to its excellent high-temperature resistance, high strength, self-lubrication, and friction resistance. In this study, the effect of different humidity levels on the tribological properties of PA66 materials in self-mated contacts are investigated using a pin-on-disk test rig. The results show that the friction coefficient and wear rate of the PA66-PA66 sliding combination increase drastically after humidity treatment mainly due to the surface plasticization caused by water absorption and the decrease of cohesive strength and glass transition temperature. Moreover, the limiting PV value of PA66 materials decreased significantly after moisture absorption, and when the actual PV value exceeds this reduced material limit, the degree of friction and wear increases drastically. The wear mechanism of the PA66-PA66 sliding combination is mainly adhesive wear without humidity treatment. The wear mechanism is adhesive wear combined with abrasive wear after humidity treatment (50%, 70%, 90%, immersion in water) and abrasive wear is most significant at 50% humidity. Abrasive wear decreases with the increase of the moisture content, while adhesive wear increases.
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