Yog tias daim ntawv qhia linear siv hauv kev siv, nws yuav tsum tau lees tias nws muaj cov nyhuv lubrication zoo. Yog tias cov nyhuv lubrication tsis ua tiav, kev sib hloov ceev yuav raug hnav hnyav, uas yuav cuam tshuam rau kev ua haujlwm thiab txo cov kev pab cuam lub neej.