{"id":559225,"date":"2024-11-05T18:23:19","date_gmt":"2024-11-05T18:23:19","guid":{"rendered":"https:\/\/pdfstandards.shop\/product\/uncategorized\/esdu-940082010\/"},"modified":"2024-11-05T18:23:19","modified_gmt":"2024-11-05T18:23:19","slug":"esdu-940082010","status":"publish","type":"product","link":"https:\/\/pdfstandards.shop\/product\/publishers\/esdu\/esdu-940082010\/","title":{"rendered":"ESDU 94008:2010"},"content":{"rendered":"<p><strong>INTRODUCTION<\/strong><\/p>\n<p>A cam\/follower system will fail to perform its intended function<br \/>\nadequately if the surfaces of the cam and\/or the follower are worn<br \/>\nexcessively. This type of early service failure can often be<br \/>\navoided if the system is designed such that an adequate lubricant<br \/>\nfilm is present in the contact region throughout the life of the<br \/>\nsystem. Therefore the prediction of the thickness of such a<br \/>\nlubricant film under a variety of operating conditions is a vital<br \/>\nstep in the systematic design of a cam mechanism (see ESDU 94017,<br \/>\nReference 28).<\/p>\n<p>This Data Item presents a procedure for calculating values of<br \/>\nlubricant film thickness in the contact region between a disc cam<br \/>\nand its follower (either rolling or sliding contact). To determine<br \/>\nfilm thickness it is necessary to find the radius of curvature of<br \/>\nthe cam profile, the lubricant entrainment velocity and the contact<br \/>\nforce at the interface between the cam and the follower for a<br \/>\nseries of angular positions of the cam. This analysis is time<br \/>\nconsuming and is best carried out using the computer program (see<br \/>\nSection 7) supplied with this Data Item. The program determines<br \/>\nvalues of minimum film thickness at intervals of one degree of cam<br \/>\nrotation (assuming constant angular velocity of the cam) and finds<br \/>\nthe smallest value of film thickness during the cycle. The program<br \/>\ncan be used to determine suitable values of rate and preload for a<br \/>\nreturn spring designed to ensure that the cam and follower remain<br \/>\nin contact. Alternatively, if a spring of known rate and preload is<br \/>\nspecified the program checks that contact is maintained. A check to<br \/>\nensure that profile undercutting (see ESDU 92005, Reference 23)<br \/>\ndoes not occur is also included.<\/p>\n<p>The calculation method presented in this Data Item is based on<br \/>\nthe theory of elastohydrodynamic lubrication (see Taylor, Reference<br \/>\n38, or Zhu and Taylor, Reference 39) in which changes in the<br \/>\nviscosity of the lubricant and elastic deformation of the<br \/>\ncomponents in contact are significant. The ESDU Tribology Series<br \/>\ncontains procedures for calculating film thicknesses in lubricated<br \/>\nHertzian contacts and these are given in ESDU 85027 and ESDU 89045<br \/>\nfor two dimensional line contacts and three dimensional point<br \/>\ncontacts, respectively (Derivations 2 and 3). Computer programs<br \/>\nthat implement these procedures are also available (see ESDU 91037<br \/>\nand ESDU 91038, References 21 and 22, respectively). The algorithm<br \/>\nused to calculate film thickness in the program (see Section 7)<br \/>\nsupplied with the current Data Item is exactly the same as that<br \/>\nused in ESDU 91037 (for the reasons discussed in Appendix A).<\/p>\n","protected":false},"excerpt":{"rendered":"<p><b>Lubricant Film Thickness Between Disc Cams and Followers<\/b><\/p>\n<table style=\"width: 100%\" border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td>Published By<\/td>\n<td>Publication Date<\/td>\n<td>Number of Pages<\/td>\n<\/tr>\n<tr>\n<td><a href=\"https:\/\/pdfstandards.shop\/product-category\/publishers\/esdu\/\"><b>ESDU<\/b><\/a><\/td>\n<td>2010-07<\/td>\n<td>NA<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n","protected":false},"featured_media":0,"template":"","meta":{"rank_math_lock_modified_date":false,"ep_exclude_from_search":false},"product_cat":[2675],"product_tag":[],"class_list":{"0":"post-559225","1":"product","2":"type-product","3":"status-publish","5":"product_cat-esdu","7":"first","8":"instock","9":"sold-individually","10":"shipping-taxable","11":"purchasable","12":"product-type-simple"},"_links":{"self":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product\/559225","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/types\/product"}],"wp:attachment":[{"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/media?parent=559225"}],"wp:term":[{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_cat?post=559225"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/pdfstandards.shop\/wp-json\/wp\/v2\/product_tag?post=559225"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}