タイトルまたは説明

A needle roller bearing is a bearing which uses small cylindrical rollers.The difference of a needle roller bearing and roller bearing is the ratio of diameter and length of their rollers, when the ratio of the diameter and the length of roller of a roller bearing is between the interval of 0.4 to 0.1, that roller bearing is called as needle roller bearing. They are used to reduce friction of a rotating surface.