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Bearing assembly principles, installation precautions, models and their meanings

wallpapers Tech 2020-06-14
Bearings are an important part of contemporary machinery and equipment, and their usage is staggering. Taking a car as an example, a car generally needs 100 to 150 bearings to ensure normal driving. The main function of the bearing is to support the mechanical rotating body, reduce the friction coefficient during the movement, and at the same time ensure its rotation accuracy. my country's bearing industry is developing rapidly, bearing varieties from few to many, product quality and technical level from low to high, the industry scale from small to large, has formed a professional production system with basically complete product categories and a relatively reasonable production layout. Today, the editor of Xianji.com will come to talk about the relevant knowledge about bearings, including: bearing assembly principles, installation notes, models and their meanings. Let's take a look!
 
Bearing assembly principle
 
Preparation before assembly
1. Preparation of measuring tools and tools.
2. Inspection of parts: such as the processing quality inspection of shafts, housings, end caps, bushings, sealing rings and other parts. The surface matched with the bearing should not have depressions, burrs, rust and solid particles.
3. Cleaning of parts: Before installing the bearing, use diesel or kerosene to clean the shaft, housing and other parts, and wipe the surface with a clean cloth (not cotton yarn), and then apply a thin layer of oil to facilitate installation. All lubricating oils are cleaned and inspected to ensure smoothness.
4. Cleaning of bearings: Bearings sealed with anti-rust oil can be cleaned with diesel or kerosene; bearings with dust caps or seal rings on both sides have been added with lubricants before leaving the factory, as long as the lubricants in the bearings are not damaged or deteriorated , The bearings can be installed without cleaning; bearings coated with anti-rust and lubricating grease can also be cleaned during installation. The bearing should be filled with lubricant immediately after cleaning, and the bearing should be turned slowly when oiling, so that the grease enters between the rolling body and the raceway. The lubricating oil (grease) for bearings must be clean and free of dirt.
 
Overhaul of shaft and bearing seat
1. Overhaul of the shaft: first check whether it is bent or deformed with a dial indicator. If there is any deformation, it should be turned, grinded or straightened. There should be no burrs or bumps on the mating surface of the shaft and the bearing, the perpendicularity of the shaft shoulder to the shaft, and the radius of the corner of the shaft shoulder should be measured.
2. Maintenance of bearing housing hole: measure the roundness and cylindricity of the bearing housing hole, check the verticality of the shaft shoulder of the bearing housing hole, etc.
 
Assembly of rolling bearings
1. Bearings with tight fit between the inner ring and the shaft, and loose fit between the outer ring and the bearing seat, the hammered end face of the assembly sleeve should be processed into a spherical shape. Where there is no press or where the press cannot be used, the bearing can be installed with an assembly sleeve and a hammer.
2. The inner ring is loosely fitted with the shaft, and the outer ring is tightly fitted with the bearing seat for bearing installation. Press the bearing into the bearing seat first, the outer diameter of the assembly sleeve should be slightly smaller than the diameter of the shell hole, and then install the shaft.
3. The inner ring and the shaft, the outer ring and the bearing seat are installed with tight-fitting bearings. The end face of the assembly sleeve should be processed into a ring that can simultaneously compress the inner and outer ring end faces of the bearing to press the bearing into the shaft and the bearing seat hole. This method is suitable for the installation of self-aligning radial ball bearings.
4. Hot (cold) assembly method of bearings. Before hot assembly, put the bearing or separable bearing ring into the oil and heat it evenly to 80~100℃ (should not exceed 100℃), then take it out and install it on the shaft quickly.
5. Disassembly of rolling bearings. Rolling bearings adopt the hot assembly method, cold assembly method and hot unloading method. The advantage is that the interference will not be damaged, and the assembly and disassembly are both labor-saving and rapid.
 
 
Bearing installation considerations
1. Avoid hard mounting and impact, you must ensure that the bearing is gently installed, and the bearing and the seat hole have a small clearance. Normally, you should tap the end face to install it in a normal position. The hole surface was injured or even scrapped.
2. The bearing inner sleeve must be heated by induction and must not exceed 120°C. It is strictly forbidden to disassemble and assemble bearings by open flame.
3. When it is not easy to install, find out the reason, take reasonable measures after eliminating the problem, and timely repair when there are problems such as parts deformation, and if necessary, please revise the drawings.
4. Inject sufficient and clean grease in strict accordance with requirements.
5. When unqualified seals, glands and other parts are found in the installation, they must be strictly scrapped or repaired to ensure that the assembly quality meets the quality requirements.

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Tag: bearing