Writer: Eric Bearing Limited
According to certain procedures, the content and requirements of the product manufacturing process are compiled and fixed in the form of documents and standards to form a process document.
The process documents can be divided into two types: one is a comprehensive process document, that is, all the requirements of a product are compiled in a single file, which is simple and clear, easy to query, and suitable for occasions with simple product structures and small production batches.
The second is the type of process documents, that is, the classification is based on the professional characteristics of product manufacturing technology, highlighting the professional characteristics, applicable to all types of products.
Rolling bearings as a standardized mechanical parts and components, except for individual varieties, the production process of most varieties is basically similar. Therefore, the compilation of manufacturing process documents for SKF bearing parts is convenient for standardization and serialization. SKF 22228-2CS5K-VT143 bearings online , pls click here :
1. Types of process documents
Bearing parts manufacturing process documents can generally be divided into three categories: dominant process documents, management process documents and production process documents.
The dominant process is the foundation, the management process file is used to supply and manage the materials needed in the part manufacturing process, and the production process file is used to guide production.
2. Basis for preparation of process documents
Mainly include: product design drawings, national standards, enterprise standards, internal standards and regulations related to products, special requirements put forward by customers, process equipment, technology and management level possessed by the enterprise, production scale and production layout, etc.
3. Features of the process documents
(1) Mandatory process documents are important regulations to ensure product quality, ensure the orderly production and carry out enterprise management. Once issued, they must be resolutely implemented.
(2) Basic process documents are the basis for the production organization, material supply, quality management and economic accounting of the enterprise, and are the basic documents for the work of each business department of the enterprise.
(3)Operability The process document not only requires accuracy, completeness, uniformity and specification, but also requires easy-to-understand, simple and clear, suitable for ordinary operation. Therefore, it must have strong operability in actual work.
(4) Corporate imagery The process document is formulated according to the actual situation of the enterprise. Its content concentrates the advantages of the enterprise in technology, management and process equipment, and reflects the strength and image of the enterprise from one aspect.
Standard for bearing size
1. Bearing measurement
The measurement of the bearing hole can be measured after checking the reference size on the outer diameter micrometer using the inner diameter gauge, and the roundness and cylindricity of the bearing hole must also be measured. Burning out SKF bearings often reduces the diameter of the bearing hole at the opening and the roundness is extremely poor, which is extremely detrimental to the normal operation of the bearing.
If the positioning of the connecting surface of the connecting rod bolt is loose, the connecting rod bearing cover will be displaced and the roundness of the bearing hole will be excessive. The roundness error of the bearing hole should be controlled within the dimensional tolerance, and the cylindricity should be strictly controlled.
2. Measurement of main dimensions of bearings
(1) Bearing thickness: the fixed probe of the outer diameter micrometer is changed from a flat surface to a spherical surface, which can be used to measure the thickness of the bearing. The thickness of the bearing should generally be controlled in the range of 0.005 to 0.010 mm, otherwise the inner diameter of the SKF bearing will be out of tolerance. The bearing is slightly thinned near the opening, and care should be taken when measuring.
(2) The tightness of the fit between the bearing and the bearing hole: the tightness of fit is guaranteed by the free spring-out of the bearing and the height of the residual surface. Under the method of measuring the height of the remaining surface: install the bearing according to the regulations, loosen one of the bolts after the bolts of the bearing cover are tightened to the specified torque, and use a feeler gauge to measure the gap at the interface of the bearing cover. The value should be in the range of 0.05~0.15 mm within.
(3) Bearing inner diameter: Before measurement, the SKF bearing should be installed according to the regulations and the bearing cap bolts should be tightened according to the specified torque. After measuring the reference size on the outer diameter micrometer with the inner diameter gauge, the measurement should avoid the thinning area. The difference between the bearing inner diameter and the corresponding journal outer diameter is the fit clearance.
(4) The coaxiality of the inner bore of the main bearing: The coaxiality error of the inner bore of the main bearing is mainly caused by the coaxiality error of its bearing bore, and the cause of the coaxiality error of the bearing bore is the deformation of the cylinder block.
When the radial runout of the main journal is within the specified tolerance, check the joint marks of the main journal and the bearings. If the positions of the joint marks of the main bearings are obviously inconsistent, it means that the coaxiality error is large. Scraping, boring bearings or Solve by replacing the cylinder block, etc., otherwise it is difficult to ensure the normal operation of the engine.