Needle Roller Bearings Can Only Bear The Radial Load
The roller bearing is equipped with a thin and long roller (roller diameter D ≤ 5mm, L / D ≥ 2.5, L for the roller length), so the radial structure is compact, its inner diameter and load capacity and other types of bearings , The smallest diameter, especially for radial installation of the size of the bearing support results. According to the use of different occasions, can be used without the inner ring bearing or needle roller and cage components, then match the bearing surface and the surface of the casing hole directly as the bearing inner and outer rolling surface, in order to ensure the load capacity and operating performance With the same ring bearing, shaft or shell hole raceway surface hardness, machining accuracy and surface quality should be similar to the bearing ring raceway. Such bearings can only withstand radial loads.
Install full complement needle roller bearings, usually with auxiliary sleeves. At this time, the auxiliary roller or auxiliary sleeve to hold the needle roller does not fall off the needle, the journal with its own chamfer to lift the needle, as the needle roller bearings in the journal to move slowly inward, auxiliary roller Or auxiliary sleeve will slowly exit until it is installed to the working position so far.
The outer diameter of the auxiliary roller and auxiliary sleeve should be 0.1-0.3mm smaller than the shaft diameter. When installing, first apply the inner surface of the bearing outer ring with grease, close the inner surface of the needle roller (into the last needle should be left when the gap), and then instead of the journal or bearing inner ring Or the auxiliary sleeve is pushed into the outer ring hole and its end face is aligned with the mounting shaft end face or the inner bearing end face of the bearing mounted on the shaft and then applied with a press or hand hammer.
Needle roller bearings can also be installed, that is, the outer diameter of the auxiliary sleeve coated with a thin layer of lubricating oil, into the bearing outer ring, so that the auxiliary sleeve and bearing outer ring to form a ring hole, and then in the ring hole in the needle. After loading the needle, use the working shaft to push the auxiliary sleeve.
For needleless bearings with no inner ring or without outer ring, the rolling surface of the shaft or shell hole can be coated with a thin layer of grease at the time of installation, and the needle is placed in close contact with the grease on the mounting part. Put the last needle when a needle should be left, the size of the gap in the needle roller bearings on the circumference of 0.5mm is appropriate. Can not put the last needle into a hard squeeze, or less loaded a needle, because the hard squeeze, the bearings will be stuck can not rotate; less equipment, the gap is too large, easy to cause the needle running when the needle Twist and break. For only the needle roller needle bearing the outer ring, because the outer ring wall is thin, do not use the hand hammer to install, should use the press press. Because the hand hammer beat, the pressure is not uniform, easy to make the needle roller bearing the outer part of the deformation.
Needle roller bearing bearing capacity, suitable for installation of the size of the support structure, the journal surface by hardening as a rolling surface, the bearing with the press fit into the seat hole, no longer need to its axial positioning.
The bearings should be filled with an appropriate amount of grease before installation. Normally, the BK bearing is not lubricated after assembly. For bearings with no extension at the end of the journal, the end seal is closed and can withstand small axial travel.