thrust bearing

January 16, 2020

Thrust bearings are generally composed of two or more thrust washers and a number of rolling elements. Generally, thrust washers are divided into shaft plates and seat plates. The most common type of rolling body is generally made of iron or copper. Quality cages are combined into a whole. The most common type of this type of bearing is a steel ball thrust bearing.
Chinese name thrust bearing field industrial classification bearing common type iron or copper cage combined into a whole
table of Contents
1 Definition
2 Industry Overview
3 working principle
4 Application classification
5 Notes
6 Applications
▪ Bearing effect
▪ Lubrication
▪ Lubrication method
▪ sealed
7 Industry Status
Definition edit
Thrust bearing is a special bearing used to specifically bear axial force, that is, a bearing in the direction of axis parallel. Thrust bearing is also called thrust bearing. [1]
Industry Profile Editor
According to data from the National Bureau of Statistics, in 2011, there were 1,416 companies in China's bearing manufacturing industry (annual sales income of more than 20 million yuan). The total annual industrial output value was 193.211 billion yuan, a year-on-year increase of 27.59%. The year-on-year growth was 30.30%; the total profit was 12.523 billion yuan, an increase of 26.54% over the previous year. It is estimated that by 2015, China's bearing production is expected to exceed 28 billion sets, and its main business income is expected to reach 210 billion yuan, becoming the world's largest bearing production and sales base. At present, China's bearing industry is facing three major problems: low concentration of production, low R & D and innovation capabilities, and low level of manufacturing technology. First, the concentration of industrial production is low. In the world's bearing sales of about 30 billion US dollars, the world's eight largest multinational companies account for 75% to 80%. Germany's two major companies account for 90% of its national total, Japan's five companies account for 90% of its national total, and the US one accounts for 56% of its national total. The 10 largest bearing companies in China, such as axles, have sales of only 24.7% of the entire industry, and the production concentration of the top 30 companies is only 37.4%. Second, low R & D and innovation capabilities. The industry's basic theoretical research is weak, participation in the formulation of international standards is weak, and there are fewer original technologies and fewer patented products. At present, our design and manufacturing technology is basically imitated, and our product development capability is low, as shown in the following: Although the supporting rate for domestic hosts reaches 80%, high-speed railway passenger cars, mid-to-high-end cars, computers, air conditioners, high-level rolling mills, etc The supporting and maintenance bearings of the main engine are basically imported. Third, the level of manufacturing technology is low. The development of China's bearing industry manufacturing technology and process equipment technology is slow, the numerical control rate of turning is low, and the level of grinding automation is low. There are only more than 200 automatic production lines in the country. Advanced heat treatment processes and equipment that are important to bearing life and reliability, such as controlled atmosphere protection heating, double refinement, and bainite quenching, have low coverage, and many technical problems have not been solved. The research and development of new bearing steel grades, the improvement of steel quality, the research and development of related technologies such as lubrication, cooling, cleaning and abrasive tools can not meet the requirements of improving the level and quality of bearing products. As a result, the process capability index is low, the consistency is poor, the product processing size is large in dispersion, and the inherent quality of the product is unstable, which affects the accuracy, performance, life and reliability of the bearing. [1]
How it works
Thrust ball bearing is a separate bearing. The shaft ring and seat ring can be separated from the cage and steel ball components. Shaft washer is matched with shaft, seat washer is matched with bearing housing hole, there is gap between shaft and thrust ball bearing can only bear axial load, one-way thrust ball bearing can only bear Axial load in one direction, two-way thrust ball bearings can withstand axial loads in two directions; thrust ball bearings can not limit the radial displacement of the shaft, the limit speed is very low, one-way thrust ball bearings can limit one of the shaft and the housing Axial displacement in the direction, two-way bearings can limit axial displacement in both directions. Thrust roller bearings are used to support axial and radial combined loads that are mainly axial loads, but the radial load must not exceed 55% of the axial load. Compared with other thrust roller bearings, this type of bearing has a lower friction factor, higher speed, and self-aligning performance. 29000 type rollers are asymmetrical spherical rollers, which can reduce the relative sliding of rollers and raceways during work, and have long rollers, large diameters, large number of rollers, high load capacity, usually oil lubrication , Individual low-speed situations can be lubricated with grease. When designing and selecting, it should be preferred; 80000 thrust cylindrical roller bearings, 90000 thrust tapered roller bearings and AXK thrust needle roller bearings can withstand unidirectional axial load, which is better than the axial of thrust ball bearings The load capacity is much larger, and the rigidity is large and the axial space is small. Thrust cylindrical roller bearings and thrust needle roller bearings are suitable for occasions with low speed. Thrust tapered roller bearings have a slightly higher speed than thrust cylindrical roller bearings. [1]
Application Category Edit
Thrust bearings are divided into thrust ball bearings and thrust roller bearings. Thrust ball bearings are further divided into thrust ball bearings and thrust angular contact ball bearings. The raceway ring is composed of a washer with a raceway, a ball and a cage assembly to cooperate with the shaft. As the shaft ring, the raceway ring matched with the shell is called the seat ring. The two-way bearing matches the middle ring with the shaft. The one-way bearing can bear the unidirectional axial load, and the two-way bearing can bear the two-way axial load. Installation of the seat ring Spherical bearings have self-aligning performance, which can reduce the impact of installation errors. Such bearings are mainly used in automotive steering mechanisms and machine tool spindles. Thrust roller bearings are divided into thrust cylindrical roller bearings, thrust spherical roller bearings, thrust Tapered roller bearings, thrust needle bearings. Thrust cylindrical roller bearings are mainly used in petroleum rigs, iron and steel machinery. Thrust spherical roller bearings are mainly used in hydroelectric generators, vertical motors, ship propellers Shafts, tower cranes, extruders, etc. Thrust tapered roller bearings. These bearings are mainly used: one-way: crane hooks, swivel rings of oil rigs. Two-way: rolling mill roll necks. Planar thrust bearings mainly bear axial in the assembly Load , Its application is wide. Although the thrust bearing installation operation is relatively simple, errors often occur during actual maintenance, that is, the tight and loose ring installation positions of the bearings are incorrect. As a result, the bearings are rendered ineffective and the journals are quickly worn. The clamping ring is mounted on the end face of the stationary part, which means that it is incorrectly assembled. The inner ring of the tight ring and the journal are a transitional fit. When the shaft rotates, the tight ring is driven and friction with the end face of the stationary part. When the axial force (Fx) is applied, the friction torque will be greater than the inner diameter matching resistance torque, resulting in tightness. The mating surface of the ring and the shaft is forced to rotate, which intensifies the journal wear. [1]
Notes edit
Pay attention to the following points when installing thrust bearings. (1) Distinguish the tight ring and loose ring of the bearing (according to the size of the bearing inner diameter, the hole diameters differ by O.1 ~ O.5mm). (2) Distinguish the stationary parts of the mechanism (that is, the parts that do not move, mainly referring to the assembly). (3) In any case, the loose ring of the bearing should always rest on the end face of the stationary part. [1]
Application Editing
Bearing effect
In terms of its function, it should be a support, that is, the literal interpretation is used to support the shaft, but this is only a part of its function. The essence of support is to be able to bear radial loads. Can also be understood as it is used to fix the shaft. The bearing selection of fast, easy and excellent automation is included. It is to fix the shaft so that it can only achieve rotation, and control its axial and radial movement. The motor will not work at all without bearings. Because the shaft may move in any direction, and the motor is required to rotate only when the motor is operating. In theory, it is impossible to realize the role of transmission. Not only that, the bearing will also affect the transmission. In order to reduce this effect, good lubrication must be achieved on the bearings of high-speed shafts. Some bearings already have lubrication, called pre-lubricated bearings, and Most bearings must have lubricating oil, which is responsible for not only increasing energy consumption due to friction at high speeds, but also it is very easy to damage the bearings. The idea of ​​turning sliding friction into rolling friction is one-sided, because there is something called a sliding bearing. [1]
The lubricating purpose of rolling bearings is to reduce the internal friction and wear of the bearing, to prevent burning and sticking; to extend its service life; to discharge frictional heat and cooling to prevent the bearing from overheating and to prevent the lubricant from aging itself; also to prevent foreign objects from entering the bearing or to prevent rust and corrosion The effect. [1]
Lubrication method
Bearing lubrication methods are divided into grease lubrication and oil lubrication. In order to make the bearing perform well, first of all, it is necessary to choose a lubrication method suitable for the conditions and purposes of use. If only lubrication is considered, the lubricity of oil lubrication is dominant. However, grease lubrication has the advantages of simplifying the structure around the bearing, comparing the advantages and disadvantages of grease lubrication and oil lubrication. Pay special attention to the amount of lubrication, whether it is oil lubrication or grease lubrication, too little amount of lubrication does not fully affect bearing life, too much amount will cause large resistance, affecting speed. [1]
Bearing sealing can be divided into two types: self-contained seal and external seal. The so-called bearing seal is manufactured by the bearing itself to have a sealing performance device. Such as bearings with dust caps, seals and so on. This seal occupies a small space, is easy to install and remove, and has a relatively low cost. The so-called bearing plus seal performance device is a seal device with various performances manufactured inside the mounting end cap and the like. Bearing seals are divided into non-contact seals and contact seals. Among them, non-contact seals are suitable for high-speed and high-temperature occasions, and have different structural forms such as gap type, labyrinth type and gasket type. The contact seal is suitable for medium and low speed working conditions. There are commonly used structural forms such as felt seals and leather bowl seals. [1]
Industry Status Editor
According to the data of "China Bearing Manufacturing Industry Production and Sales Demand Forecast and Transformation and Upgrade Analysis Report", from 2009 to 2013, China's bearing manufacturing industry's total industrial output value has been increasing year by year. In 2013, the industry realized a total industrial output value of 249.363 billion yuan, a year-on-year increase of 12.92%. An analysis of the data in the past five years found that from 2009 to 2013, the sales revenue of the Chinese bearing manufacturing industry also showed an increase year by year. In 2013, it realized sales income of 249.012 billion yuan, a year-on-year increase of 11.80%. The rapid development of China's bearing industry, from small to many bearing types, product quality and technical level from low to high, industry scale from small to large, has formed a professional production system with basically complete product categories and a reasonable production layout.