A new experimental approach for measuring thermal behaviour in the case of nylon 6/6 cylindrical gears

Letzelter, Eric; Guingand, Michèle; Vaujany, Jean Pierre de; Schlosser, Pauline

doi:10.1016/j.polymertesting.2010.09.002

Cited by 52 publications

(38 citation statements)

References 14 publications

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“…Like with shrinkage, the expansion is not even along the tooth height. The literature [23] states that a change in the centre distance and, consequently, a change in the lateral backlash, significantly affects the lifetime of the gears. From this we can conclude that an error in the centre distance affects the lifetime of polymer S-gears, due to the changed kinematics of meshing.…”

Section: Lifetime Test Resultsmentioning

confidence: 99%

“…In addition, the position of the thermal camera is vital for measuring the temperature during operation. If positioned above the gears, it cannot measure an accurate temperature due to the turbulent disturbances caused by meshing gears [23]. However, positioning the camera at an angle can cause changes in the emissivity, which can also affect a measurement made with a thermal camera [23].…”

Section: Testing Conditionsmentioning

confidence: 99%

“…If positioned above the gears, it cannot measure an accurate temperature due to the turbulent disturbances caused by meshing gears [23]. However, positioning the camera at an angle can cause changes in the emissivity, which can also affect a measurement made with a thermal camera [23]. A special design of the testing device makes it possible to align the camera with the gear's rotational axis (Fig.…”

Section: Testing Conditionsmentioning

confidence: 99%

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The effect of the teeth profile shape on polymer gear pair properties

2016

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Original scientific paper The paper presents an extensive research on two different tooth-flank geometries, i.e. involute and S-gears. A significant difference between the two analyzed geometries was observed during the lifetime testing. The tests were conducted on special test equipment with an axis distance of 20 mm. The material used for the tested gears was POM for the driver gear and PA6 for the driven gear. The same sizes of driver and driven gears were used (m = 1 mm, z = 20). Gears of this size are particularly suitable for micro-gear transmissions. The tests were carried out using different rotational speeds and torques, between 0,8 N·m and 1,5 N·m. During testing the thermal state of the gears was measured with a thermal camera. The stress and deformation analyses of the tested gears were undertaken using numerical simulations employing the finite-element method. Keywords: failure; involute gears; polymer; S-gears; temperature Utjecaj oblika profila zuba na svojstva para polimernih zupčanikaOriginal scientific paper U radu se predstavlja opsežno istraživanje dviju različitih geometrija boka zuba t.j. evolventnih i S-zupčanika. Zapažena je značajna razlika između te dvije analizirane geometrije tijekom ispitivanja njihovog vijeka trajanja. Ispitivanja su provedena na posebnoj opremi za ispitivanje s udaljenošću vratila od 20 mm. Materijal ispitivanih zupčanika bio je POM za pogonski zupčanik i PA6 za pogonjeni zupčanik. Rabljene su iste veličine pogonskog i pogonjenog zupčanika (m = 1 mm, z = 20). Zupčanici te veličine su naročito pogodni za mikro zupčanični prijenos. Ispitivanja su provedena uz različite brzine vrtnje i okretne momente, između 0,8 N·m i 1,5 N·m. Tijekom ispitivanja toplinskom se kamerom mjerilo toplinsko stanje zupčanika. Analize naprezanja i deformacije ispitivanih zupčanika provedene su numeričkom simulacijom primjenom metode konačnih elemenata.

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Section: Lifetime Test Resultsmentioning

confidence: 99%

Section: Testing Conditionsmentioning

confidence: 99%

Section: Testing Conditionsmentioning

confidence: 99%

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The effect of the teeth profile shape on polymer gear pair properties

2016

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“…With polymer gears, the main reason for failure is increased gear temperature and the accompanying changes in the mechanical properties of the material. Letzelter et al (2010) found that a slight increase in axis distance, and the resulting increased backlash, significantly increases the lifespan of polymer gears. With increased backlash the gear pair captures more air in the gaps between the teeth, which has the beneficial effect of heat dissipation away from the gear.…”

Section: Gear Test Rigmentioning

confidence: 99%

Different teeth profile shapes of polymer gears and comparison of their performance

Zorko

Kulovec²,

Tavčar

et al. 2017

JAMDSM

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This article presents a lifespan testing analysis of polymer gears manufactured by cutting. Compared to injection molding, machine cutting provides higher accuracy of gear geometry. Two different tooth flank geometries were tested; i.e. involute and S-gears. In theory, S-gears have several advantages over involute gears due to the convex/concave contact between the matching flanks. The theoretical tooth flank geometry of S-gears provides more rolling and less sliding between the matching flanks, compared to involute gears. The convex/concave contact leads to lower contact stress, which in combination with less sliding means lower losses due to sliding friction and consequently less heat generated. The goal of our research was to prove that tooth flank geometry affects the lifetime of polymer gears, and to find the mechanisms and quantitative differences in the performance of both analyzed geometries. The gears were tested on specially designed testing equipment, which allows exact adjustment of the central axis distance. Two different material pairs (POM/POM and POM/PA66) of the drive and driven gears were tested. Each test was done at a constant moment load and a constant rotational speed. Several tests were conducted using the same conditions due to repeatability analysis. All the tests were performed till the failure of the gear pair and without lubrication. In lifespan testing, the polymer S-gears showed better performance and longer lifespan than involute polymer gears.Keywords : Polymer gears, Lifespan testing, Temperature, S-gears, Involute IntroductionThe involute shape of the tooth flank was suggested by Leonard Euler (1775). Due to its unique properties, the involute shape of the tooth flank prevailed and most of the gears nowadays are involute. The condition that a tooth flank shape should fulfil in order to provide a constant gear ratio is defined by the law of gearing. Many curves, not just the involute one, fulfil it, which has yielded many other tooth flank shapes that are rarely used in practice. The purpose of developing new gear shapes is to improve the disadvantages of involute gears, such as: the convex/convex contact, teeth undercutting, and gears with a small number of teeth have a shorter dedendum, which leads to increased sliding and losses due to friction. Besides involute gearing, cycloidal gearing is the next best known type, mainly used in wrist watch mechanisms. Kapelevich (2013) dedicated much of his research work to gears with asymmetric tooth flanks, where the active tooth flank is still of involute shape. Mohan and Senthilvelan (2014) studied the lifespan of asymmetric composite gears. Kim (2006) and Düzcükoglu (2009) also worked on improving the performance of polymer gears. They used the involute tooth profile and attempted to extend the lifespan of gears by virtue of geometric changes in teeth width. Koide et al. (2017) investigated the impact of the sine-curve gear on the tooth surface temperature and gear power transmission efficiency. Hlebanja et al. (2008) suggeste...

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“…As the transmissible power levels increase, problems of surface temperatures arise due to the frictional losses between mating gear teeth. 2,3 Most of these coatings are based on zinc and aluminium, which are mainly used for radio frequency shielding and electrical conductivity where the mechanical properties of the coatings are not of prime importance. The use of polymer with good strength to weight ratio as a base material is an alternative to metallic components.…”

Section: Introductionmentioning

confidence: 99%

The influence of surface coatings on the tooth tip deflection of polymer gears

Trobentar¹,

Glodež²,

Flašker³

et al. 2016

Mater. Tehnol.

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When designing gear drives made of polymer, the tooth tip deflection is a crucial parameter in respect to the proper gear drive operation. Excessive tooth tip deflection can lead to serious disturbances of gear meshing and consequently to increased noise and wear of the teeth flanks. In such cases the tooth tip deflection can be reduced through the use of stiff surface coatings on the tooth flanks. In this paper the influence of different coating materials and thicknesses on the tooth tip deflection of polymer gears is analysed using comprehensive finite element computational analysis. The numerical results obtained are then used to define an approximate equation for the calculation of gear tooth tip deflection for the coating material used and the thickness of the surface coating layer. The results show that the tooth tip deflection decreases with large values of the coating material Young's modulus and with the coating layer thickness. Keywords: polymer gears, surface coatings, tooth deflection, numerical analysis Pri konstruiranju zobni{kih dvojic s polimernimi zobniki je poves vrha zoba zobnika eden klju~nih dejavnikov, ki vpliva na pravilno delovanje zobni{ke dvojice. Prevelik poves vrha zoba namre~vodi do resnih motenj pri ubiranju zobni{ke dvojice, kar povzro~i ve~ji hrup in tudi ve~jo obrabo zobnih bokov. V tak{nih primerih lahko poves vrha zoba zobnika zmanj{amo z uporabo togih povr{inskih prevlek. V predlo`enem prispevku je predstavljena obse`na numeri~na analiza po metodi kon~nih elementov, ki zajema vpliv materiala trde prevleke in debeline prevleke na poves vrha zoba zobnika. Numeri~ni rezultati so nato uporabljeni za dolo~itev aproksimativne ena~be za izra~un povesa vrha zoba zobnika v odvisnosti od izbranega materiala prevleke in njene debeline. Kon~ni rezultati ka`ejo, da se poves vrha zoba zmanj{uje z ve~anjem modula elasti~nosti prevleke in debeline utrjenega povr{inskega sloja zobnih bokov. Klju~ne besede: polimerni zobniki, povr{inske prevleke, poves zoba, numeri~ne analize

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A new experimental approach for measuring thermal behaviour in the case of nylon 6/6 cylindrical gears

Cited by 52 publications

References 14 publications

The effect of the teeth profile shape on polymer gear pair properties

The effect of the teeth profile shape on polymer gear pair properties

Different teeth profile shapes of polymer gears and comparison of their performance

The influence of surface coatings on the tooth tip deflection of polymer gears

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