Frictional Losses of Polyamides Mounted on Tensioning Guides in Contact with Chains

Radu Gabriel Velicu,Cornel Catalin Gavrila,Mihai Tiberiu Lates

doi:10.3390/ma15041345

Radu Gabriel Velicu, Cornel Catalin Gavrila + Show 1 more

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https://doi.org/10.3390/ma15041345

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Journal: Materials	Publication Date: Feb 11, 2022
Citations: 1	License type: CC BY 4.0

Affiliation: Transylvania University of Brașov

Abstract

The development of polyamides has increased in recent years due to scientific research and the aim of the industry to find materials characterized by good frictional behavior at high temperatures, high loads and high speeds. The wide areas of application of polyamides in the mechanical contacts with relative motions offered new development opportunities for polyamides (PA), such as PA66, PA46 and PTFE mixed PA46. One of the applications of these polyamides in mechanical contacts with relative motions is the contact between the timing chains and the active part of the tensioning guides. For a comparison with a previous study of friction of PA66, PA46 and PTFE mixed PA46, performed on a pin-on-disk tribometer, this study is based on performing tests on the same materials, on the tensioning guide of a silent chain used as a timing chain in combustion engines, with lubricating conditions much closer to the application field. The diagrams comparatively present the variation of the percentage of frictional losses for PTFE mixed PA46, PA46 and PA66 polyamides mounted on tensioning guides in contact with chains. The results clearly show that the PTFE mixed PA46 polyamide has smaller frictional losses than the PA46 and the PA66 polyamides, but the influence of speed and tensioning is also important. A comparison with the previous study is also useful for making a decision on using a polyamide for the guide of a timing chain.

Highlights

One of the aims of developing new materials is to obtain better mechanical properties which ensure higher durability of the mechanical systems in which they are used
The lubricating conditions on the tribometer are proper for boundary lubrication but not for hydrodynamic lubrication. This is the reason why the present paper studies the frictional behavior of the PTFE mixed PA46, the PA46 and the PA66 polyamides in conditions much closer to the case of the contact between the active part of the tensioning guide and the timing chain drive used for combustion engines
The aim of this paper is to evaluate the frictional losses, depending on speed and load, in a practical use of the polyamides as the active part of the tensioning guide used in a chain drive transmission

Summary

Introduction

One of the aims of developing new materials is to obtain better mechanical properties which ensure higher durability of the mechanical systems in which they are used. The durability, as one of the performance criteria which is considered in the design process of the mechanical systems, is strongly connected to the tribological properties (wear, friction) of the mechanical parts being in contact and in relative motion. One of the domains focused on development of new materials is represented by the polymers, with their subdomain, the polyamides. The development of this field is sustained by the necessity of finding new materials characterized by low friction, with application in areas such as mechanical transmissions, medical devices, the food industry, electronics and the chemical industry. The authors of [2] studied the physical behavior of silicon carbide crystals and films from the phase transformation point of view, and the correlation with the physical materials’ behavior

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