experimental investigation into the tractive prerolling behavior of balls in v-grooved tracks

Hindawi Publishing Corporation Advances in T ribology V olume 2008, Article ID 561280, 10 pages doi:10.1155/2008/561280 Research Article Experimental Investigation into the Tractive Prerolling Beha vi or of Balls in V-Gr oo ved T racks Kris De Moe rlo oze and Farid Al-Bender Mechanical Engineering Department, Division PMA, Katholieke Universiteit Leuven, Celestijnenlaan 300B, 3001 Heverlee, Belg ium Correspondence should be addressed to Farid Al-Bender, [email protected] Received 19 September 2007; Revised 8 January 2008; Accepted 27 February 2008 Recommended by Farshid Sadeghi In a rolling element system, the period of transition between motion commencement and the attainment of steady state, gross rolling, and termed prerolling is of common concern to many engineer ing applications. This region is marked by hysteresis friction behavior, with a characteristic friction-displacement curve, which is in particular relevant to motion characterization and control iss ues. In a pre vious paper, the authors car riedout a the ore tic al ana lys is of tra cti ve pr ero lli ng, lea din g to a mod el for simula tin g thi s phenomenon. The present paper is dedicated to the experimental investigation of tractive prerolling friction behavior, including validation of the theoretical model. Firstly, a kinematic analysis of the rolling motion in V-grooved tracks is carried out. Secondly, the influence of the normal load on the frictional behavior, in prerolling up to the attainment of gross rolling, is investigated on a dedicated test setup. Finally, the newly developed theoretical model is validated by comparison with the experimental results. Satisfactory agreement is obtained between theory and experiment. Copyright © 2008 K. De Moerlooze and F. Al-Bender. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 1. INTRODUCTION The characterization of rolling friction is a pertinent issue in man y fiel ds ranging fro m rol ling st ock, air craf t serv o sys te ms, and rotary and linear positioning systems to the control of miniature reading/writing heads, friction drives, and high preci sion systems . This topic has therefor e been gaining importance over the last decades, owing to the increasing demands of industrial applications on positioning accuracy, wear, and controllability. A common concern in all these applications is the rolling element system’ s behavior between motion reversal points, in other words, the period between motion commencement and the attainment of gross rolling. This period is referred to as prerolling, which is akin to presliding in sliding contacts [1–3]. Prerolling is marked by a clea r hys tere sis behavior with nonlo cal memo ry, which lies at the root of the strongly nonlinear dynamic behavior that characterizes systems comprising rolling elements [ 4, 5]. The design parameters of rolling element systems, such as preload, ball diameter, and track groove angle, evidently, have their influence on the frictional behavior of the system. Despite this fact, a coherent, systematic theory that correlates behavior with parameters has not yet received the attention it des erv es in the literature, owi ng to man y rea sons, in particular the complexity and the strong nonlinearity of the rolling contact problem. Rolling resistance or, as it is often called, rolling friction arises from two bas ic mec han isms: int ernal mec hanica l los ses in the bulk of rolling objects and external tractions in the rolling contact patch. In case of elastic rolling objects (such as metallic objects), the former is generally negligible in mag nit ude in compar iso n with the lat ter . This paper is concerned with tractive rolling; more specifically that, which is caused by creepages in the rolling motion, in particular, spin creepage. When an elastic body of revolution rolls tractively over anothe r , the trac tion fiel d in the con tact pat ch cha nge s pro gre ssi vel y with the dis tance tra ve rse d fro m its ini tia l distribution until it reaches a certain steady-state distribution. This distribution, which is independent of the initial field prior to commencement of rolling, does not vary with further rolling. This eventual rolling regime is termed gross rolling; the period building up to it, from commencement of rolling, is termed the prerolling regime. The resultant

experimental investigation into the tractive prerolling behavior of balls in v-grooved tracks

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