Deep Groove Ball Bearing 6217ZZ

The automobile industry is an important pillar industry in our country and occupies a place that cannot be ignored in the entire processing and manufacturing industry. Bearings can be seen in many parts of the car body. They have the special mission of bearing loads, reducing friction, and guiding moving parts. With the continuous progress of my country's economic development and industrial technology, China has become a major bearing production country, including automotive bearing steel. However, there is still a large gap with first-class manufacturers such as Germany's Schaeffler, Sweden's SKF, the United States' TIMKEN, and Japan's KOYO. Materials As the source, future efforts will still be to strictly control metallurgical quality, non-metallic inclusion levels, carbide size and distribution, and improve heat treatment technology.

Heat treatment is a key process in the automotive bearing manufacturing process. Its processing quality and raw materials are two important factors that affect the life of the bearing. Heat treatment has an important impact on the microstructure, mechanical properties, surface quality, dimensional and shape accuracy and stability of bearings and other parts under use conditions. Therefore, optimize the heat treatment process, select suitable heat treatment parameters, and obtain the usage conditions and conditions of the workpiece. The best comprehensive performance suitable for the failure mode is an important issue in heat treatment technology.

1. Application of bearing materials in automobiles

As we all know, bearings are composed of four parts: outer ring, inner ring, rolling elements (ball, cylindrical, tapered or needle roller, etc.) and cage. Some have sealing rings. In addition to sealing rings and part of the cage, the rest The manufacturing material is mainly bearing steel.

When selecting the type and model of automobile bearings, it is mainly based on the nature, direction, size of the load, the working environment of the actual location, as well as the requirements for the bearing's rigidity, limit speed, life, accuracy, etc., and is generally completed by the designer. Bearings are widely used in vehicles and vary with vehicle type, installation location and manufacturer, as shown in Figure 1.

(1) Power system bearings

The engine is the heart of the car, continuously providing power to other components. The internal bearings were previously dominated by sliding bearings. Nowadays, most of them use sealed ball bearings on the premise of improving bearing performance. Figure 2 shows several typical bearings in engines.

The alternator bearing is a single-row sealed ball bearing, which is mainly affected by centripetal force. It is required to operate reliably when the speed exceeds 2000r/min and the temperature exceeds 180°C. The rings and rolling elements are made of high-purity GCr15, and the hardness after heat treatment is required to be 58 ~64HRC, the cage is generally made of nylon PA46, and the sealing ring is generally made of acrylic rubber ACM. The reference standard is JB/T8167-2006.

The electromagnetic clutch bearing of the air-conditioning compressor is a double-row angular contact ball bearing. The outer ring rotates. The speed of the air-conditioning pulley can reach 7000~13000r/min. The maximum temperature is 160°C. The material is the same as above. The cage is changed from a part of an ordinary single spherical pocket. Cylindrical surface, the reference standard is JB/T10531-2005.

The tensioner and idler bearings are high-performance sealed ball bearings. The former acts on the loose edge of the synchronous transmission belt, and the latter acts on the tight edge of the synchronous conveyor belt. The materials are basically the same as above. The cage can be made of engineering plastics, 08 steel or 10 steel. Manufactured, the sealing ring is made of ACM or FPM (fluorine rubber), and the reference standard is JB/T10859-2008.

Water pump shaft bearings are generally double-row ball bearings, and their radial dimensions are smaller than ordinary bearings. It is essentially a double bearing system with a simplified structure. The two supported bearings do not have inner rings. The raceways of the rolling elements are directly formed on the shaft. The outer rings of the two supported bearings are made into a whole. Both sides are sealed with seals. Its rollers are usually made of high-chromium bearing steel. The materials of the shaft and outer ring are made of carburized steel or high-chromium bearing steel. The reference standard is JB/T8563-2010.