Fully loaded cylindrical roller bearings are designed to withstand heavy loads. Under the same width, compared with the traditional bearing with cage, this kind of bearing has extremely high bearing capacity, small radial section, which can save space, but the speed is relatively low. In order to make the bearing work normally, under the condition of continuous operation, the bearing must bear a certain minimum load, that is, c/p<25. Otherwise, the wear will be aggravated due to insufficient lubrication and high-speed operation. All multi row cylindrical roller bearings have a lubrication groove and a lubrication hole on the outer ring.