GB/T 2687-1981 Sliding bearings Powder metallurgy spherical bearings Types, dimensions and tolerances GB/T2687-1981 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Sliding Bearingswww.bzxz.net
Types, Dimensions and Tolerances of Powder Metallurgy Spherical Bearings GB 2687-81
This standard applies to powder metallurgy spherical bearings (hereinafter referred to as bearings) with an inner diameter of 1 to 20 mm for general use in various machinery. 1 The bearing type is specified in the following figure. Chamfers may be manufactured according to (a) or (b) in the figure. (a)
Marking Example
Class 7 bearings with an inner diameter of 10 mm, a ball diameter of 22 mm, and a length of 14 mm are marked as: Bearings
GB 2687--81
Inner Diameter Dimension Accuracy
Note: The bearing material brand marking is in accordance with the provisions of GB2688-81 "Technical Conditions for Sliding Bearings and Powder Metallurgy Bearings". 2 The inner diameter, ball diameter, length, incomplete spherical surface length and chamfer dimensions of the bearing are specified in Table 1. National Standards
Bureau of Standardization
The First Ministry of Machinery Industry of the People's Republic of China proposed (b)
Implemented on January 1, 1982
Beijing Powder Metallurgy Research Institute
Shanghai Textile Bearings, etc.
GB 2687--81
*A cylindrical surface is allowed in the center of the bearing length, and its length (maximum) is α, the length of the incomplete spherical surface
(maximum)
(maximum)
3 The size tolerance of the bearing shall be in accordance with GB1800-79 "Tolerances and Fits", and the shape and position tolerances shall be in accordance with GB1182~1184--80 "Shape and Position Tolerances". Bearings are divided into 7 and 8 grades according to the inner diameter size tolerance. The inner diameter, ball diameter, length size tolerance and the circular runout tolerance of the ball diameter to the inner diameter shall be as specified in Table 2. Table 2
Bearing grade
"Diameter runout of ball to inner diameter"
*Classified by ball diameter size.
4According 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 ball diameter should be equivalent to √6, and the remaining parts should be equivalent to √4~√3.
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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