GB/T 2685-1981 Sliding bearings - Powder metallurgy cylindrical bearings - Types, dimensions and tolerances

GB/T 2685-1981 Sliding bearings Powder metallurgy cylindrical bearings Types, dimensions and tolerances GB/T2685-1981 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Sliding Bearings
Types, Dimensions and Tolerances of Powder Metallurgy Cylindrical Bearings GB 2685-—81
This standard applies to powder metallurgy simple bearings (hereinafter referred to as bearings) with an inner diameter of 0.8 to 60 mm for general use in various machinery. 1 The bearing type is specified in the following figure. The chamfer can be manufactured according to (a) or (b) in the figure. C
* The outer diameter chamfer can be 30° as required. Marking Example
Marking of Grade 7 bearings with an inner diameter of 20 mm, an outer diameter of 26 mm, and a length of 25 mm; Bearing 20G7×26×25GB2685—81
-Outer diameter
-Inner diameter Dimensional accuracy
-Inner diameter
Note: The bearing material brand marking is in accordance with the provisions of GB2688-81 "Technical Conditions for Sliding Bearings and Powder Metallurgy Bearings". Issued by the State Administration of Standardization
The First Ministry of Machinery Industry of the People's Republic of China proposed to be implemented on January 1, 1982
Beijing Powder Metallurgy Research Institute.
Shanghai Textile Bearing Factory
GB2685-81
2 The inner diameter, outer diameter and chamfer dimensions of the bearing shall be as specified in Table 1, and the length dimensions shall be as specified in Table 2. mm
Ordinary series
Note: The dimensions in brackets can be used as the second option. 286
Thin series
34 (33)
36(35)
Ordinary series
C (maximum)
Thin series
GB2685—81
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GB2685—81
3The dimension tolerance of bearings shall be in accordance with GB1800—79 "Tolerances and fits": the shape and position tolerances shall be in accordance with GB1182~1184--80 "Shape and position tolerances". Bearings are divided into three types according to the inner diameter dimension tolerance: grade 7, grade 8 and grade 9. The inner diameter, outer diameter and length dimension tolerances and the coaxiality tolerance of the outer diameter to the inner diameter shall be in accordance with Table 3. Table 3
Bearing grade
●Grading by outer diameter.
, when outer diameter D≤24mm, s9 is used
outer diameter to inner diameter
coaxiality
4 According to the characteristics of powder metallurgy process, the surface finish of the inner diameter of the bearing should be equivalent to √7, the surface finish of the outer diameter should be equivalent to V6, and the rest of the parts should be equivalent to √4~V3.
Note: Since the bearing is a porous structure, the surface finish cannot be tested according to the method of GB1031-68 "Surface Finish". The test method can be agreed upon by both parties or determined by the sealed sample method.
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