Advantages of needle bearings: Needle roller bearings are equipped with thin and long rollers (the length of the rollers is 3 to 10 times the diameter, and the diameter is generally not greater than 5mm), so the radial structure is compact. When its inner diameter and load capacity are the same as other types of bearings, the outer diameter is the smallest, which is especially suitable for supporting structures with limited radial installation dimensions. Needle roller bearings should be combined with the bearing ring and application according to the different occasions, the machining accuracy and surface quality. Needle roller bearings are bearing units that combine radial needle roller bearings and thrust bearing components.
ball bearing
Contrast of needle roller bearings:
1. The friction coefficient of rolling bearings is smaller than that of sliding bearings, and the transmission efficiency is high. Generally, the friction coefficient of sliding bearings is 0.08-0.12, while the friction coefficient of rolling bearings is only 0.001-0.005;
2. Rolling bearings have been standardized, serialized and generalized, suitable for mass production and supply, and are very convenient to use and maintain;
3. Rolling bearings are made of bearing steel and undergo heat treatment. Therefore, rolling bearings not only have high mechanical properties and long service life, but also save the more expensive non-ferrous metals used in the manufacture of sliding bearings;
4. The internal clearance of the rolling bearing is very small, and the machining accuracy of each part is high, so the running accuracy is high. At the same time, the rigidity of the bearing can be increased by preloading. This is very important for precision machinery;
5. Some rolling bearings can bear radial load and axial load at the same time, therefore, the structure of bearing support can be simplified;
6. Due to the high transmission efficiency and low heat generation of rolling bearings, the consumption of lubricating oil can be reduced, and the lubrication and maintenance are more convenient;
7. Rolling bearings can be easily applied to any axis in space.
Rolling bearings are generally composed of four parts: outer ring, inner ring, rolling body and cage. Strictly speaking, it is composed of six parts: outer ring, inner ring, rolling body, cage, seal and lubricating oil. Simply put, as long as it has an outer ring, an inner ring, and rolling elements, it can be defined as a rolling bearing. According to the shape of the rolling elements, rolling bearings are divided into two categories: ball bearings and roller bearings. Bearings whose rolling elements are needle rollers are needle roller bearings. A bearing whose rolling elements are balls is a ball bearing or a ball bearing.
