Elastohydrodynamic Traction and Film Thickness at High Speeds

IF 2.9 3区工程技术 Q2 ENGINEERING, CHEMICAL

Tribology Letters Pub Date : 2024-07-18 DOI:10.1007/s11249-024-01894-w

Alexander MacLaren, Amir Kadiric

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Abstract

A renewed interest in elastohydrodynamic lubrication (EHL) phenomena at high speeds, for which thermal effects strongly influence both traction and film thickness, has grown out of the challenges presented by high-speed geared transmissions in electric vehicles. This study uses a new ball-on-disc set-up employing the well-known ultra-thin-film interferometry technique to simultaneously measure EHL film thickness and traction at entrainment speeds up to 20 m/s and slide-roll ratios up to 100%. The effect of fluid composition is examined for Group I, II and III mineral oils, for two polyalphaolefins in Group IV, and for the traction fluid Santotrac 50. The effect of viscosity in the range 4–180 mPa.s is investigated by varying bulk fluid temperature. At high speeds, both film thickness and traction are considerably lower than predicted by conventional EHL theory. The contact is seen to be fully-flooded for all conditions tested. The widely-used thermal EHL correction of Gupta is shown to overcorrect for the film thickness reduction even at modest SRRs. Finally, the influence of the sliding direction on traction and film thickness is discussed for this set-up, and a thermal model is proposed to explain the observed behaviour.

Graphical abstract

Abstract Image

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高速时的弹流牵引力和薄膜厚度

由于电动汽车中的高速齿轮传动装置所带来的挑战，人们对高速状态下的弹性流体动力润滑（EHL）现象重新产生了兴趣。本研究采用了一种新的盘上球装置，采用著名的超薄膜干涉测量技术，在夹带速度高达 20 米/秒和滑辊比高达 100%的情况下同时测量 EHL 薄膜厚度和牵引力。对第 I、II 和 III 组矿物油、第 IV 组的两种聚α烯烃以及牵引流体 Santotrac 50 的流体成分影响进行了研究。通过改变散装液体的温度，研究了粘度在 4-180 mPa.s 范围内的影响。在高速运转时，薄膜厚度和牵引力都大大低于传统 EHL 理论的预测值。在所有测试条件下，接触面都被完全淹没。古普塔（Gupta）广泛使用的热 EHL 修正方法表明，即使在适度的 SRR 条件下，也会过度修正薄膜厚度的减少。最后，讨论了滑动方向对牵引力和薄膜厚度的影响，并提出了一个热模型来解释观察到的行为。

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来源期刊

Tribology Letters 工程技术-工程：化工

CiteScore

5.30

自引率

9.40%

发文量

116

审稿时长

2.5 months

期刊介绍： Tribology Letters is devoted to the development of the science of tribology and its applications, particularly focusing on publishing high-quality papers at the forefront of tribological science and that address the fundamentals of friction, lubrication, wear, or adhesion. The journal facilitates communication and exchange of seminal ideas among thousands of practitioners who are engaged worldwide in the pursuit of tribology-based science and technology.