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This standard was proposed by the State Bureau of Mechanical Industry.
This standard is under the jurisdiction of the National Technical Committee on Automobiles of Standardization Administration of China.
Limit and determination method for cleanliness of automobile telescopic damper
This standard is applicable to the cylinder damper for automotive suspension.
This standard specifies the limit and determination method for cleanliness of automobile cylinder damper assembly.
1 Limit
The cleanliness limits specified in the diameter of working cylinder connected to the damper are shown in Table 1.
Table 1
Diameter of working cylinder, mm 20 30 40 (45) 50 65
Limits, mg 40+S 55+1.5 S 60+2 S 70+2 S 70+2.5 S 80+3 S
Notes:
① S—the traveling of damper, in cm.
② The data with brackets in the table is not recommended to use.
2 Determination method
2.1 Items and sampling positions
Arbitrarily extract two assemblies that have passed the end-of-manufacturing inspection. After the assembly is disassembled, the sampling positions of components are as specified in Table 2.
Table 2
Number Item Position
1 Cylinder barrel All inner-outer surface
2 Assembly of liquid cylinder Inner surface
3 Assembly of connecting rod-piston All outer surface (not disassembled)
4 Assembly of compressed valve All outer surface (not disassembled)
5 Damper oil All oil
2.2 Filter element, cleaning fluid, appliance and device
2.2.1 Filter element
Filter membrane: 5 μm microporous membrane.
2.2.2 Cleaning fluid
No. 120 Solvent naphthas (according to the requirements of GB 1922-1980 "Solvent naphthas").
2.2.3 Appliance and device
2.2.3.1 Porcelain (or aluminum) plates (pots) and buckets with lids are equipped as required.
2.2.3.2 Nylon brush, oil gun and oil resistant rubber gloves are equipped as required.
2.2.3.3 Analytical balance with an accuracy of 10-4 g.
2.2.3.4 Oven, dryer, weighing bottle.
2.3 Operation procedures of sampling
2.3.1 Preparation
2.3.1.1 Cleanliness determination work must be carried out in the clean room.
2.3.1.2 Operators, clothing, hats, shoes, and hands shall be cleaned.
2.3.1.3 The non-determination positions of the workbench and component assembly shall be cleaned up.
2.3.1.4 Tools, containers, etc. used for cleaning shall be cleaned, after free of water and dirt, they are dried and covered with a clean plastic cloth.
2.3.1.5 The cleaning fluid used shall be filtered through a filter membrane.
2.3.1.6 Preparation of filter elements.
Place the 5 μm filter membrane in a weighing bottle with tweezers, and open the cap halfway, place it in an oven that has been heated at 90 ± 5℃ for 60 min and place it in a desiccator for 30 min, and then weigh it for use. The difference between the two weighing results of the filter membrane is not greater than 0.4 mg.
2.3.2 Operation steps
2.3.2.1 When cleaning the inner/outer surface, put the components into the container containing the cleaning fluid and wash (flush, brush) all the sampling positions repeatedly by the cleaning fluid.
2.3.2.2 When cleaning by various appliances, the cleaning fluid with impurities shall be prevented from splashing outside the container, and collected.
