JB/T 8721-1998 This standard is formulated for the first time. This standard specifies the structural type, code method, overall dimensions, tolerances and technical conditions of single magneto bearings. This standard is applicable to the production inspection of magneto bearing manufacturers and the selection and acceptance of users. JB/T 8721-1998 Rolling bearings Magneto bearings JB/T8721-1998 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Rolling Bearings Magnetorous Motor Bearings
Ministry of Machinery Industry of the People's Republic of China
This standard is formulated for the first time.
This standard is proposed and managed by the National Technical Committee for Standardization of Rolling Bearings. The drafting unit of this standard: Luoyang Bearing Research Institute of the Ministry of Machinery Industry. The main drafter of this standard: Li Feixue.
Mechanical Industry Standard of the People's Republic of China
Rolling Bearings
Magnetic Motor Bearings
This standard specifies the structural type, code method, overall dimensions, tolerances and technical conditions of single magnetic motor bearings (hereinafter referred to as bearings).
This standard is applicable to production inspection of magnetic motor bearing manufacturers and selection and acceptance by users. Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised. 1 Parties using this standard should explore the possibility of using the latest version of the following standards. Rolling bearings
Rolling bearings
Rolling bearings
Rolling bearings
Rolling bearings
Rolling bearings
Rolling bearings
Rolling bearings
Code method
Assembly chamfer limit
Principles and methods of measurement and inspection
General technical rules
Parameter symbols
Technical conditions for heat treatment of high carbon chromium bearing steel rolling bearing parts Rolling bearings
Rolling bearings
Rolling bearings
Rolling bearings
Supplementary provisions for code method
Product marking
Residual magnetism and its evaluation method
Part surface roughness measurement and evaluation method Rolling bearings Bearings and their product parts
Symbols and abbreviations (see Figure
This standard adopts the following and
d: nominal inner diameter of the bearing
D: nominal outer diameter of the bearing
B: nominal width of the inner ring
C: nominal width of the outer ring
T: nominal width of the bearing
factory; set drawing one-way chamfer size
machinery industry ministry
inspection rules
terms and symbols specified.
factory: "minimum one-way chamfer size
production: one-way chamfer size of the non-thrust end of the outer ring factory: the minimum one-way chamfer size of the factory
Code method
Code composition
The bearing code consists of a basic code and a suffix code. Basic code
The basic code of the bearing consists of the type code "" or "post-code
" and a number indicating the nominal inner diameter of the bearing in millimeters. The post-code of the bearing is located on the right side of the basic code, indicating changes in the bearing tolerance grade, part material, etc., and its code is in accordance with the regulations.
Tolerance grade is
Copper plate stamping cage
Bearing nominal inner diameter d
Outer ring outer diameter with negative deviation value of magnetic motor bearing marking
Marking example: Rolling bearing
Rolling bearing
Overall dimensions
The overall dimensions of the bearing are in accordance with the table
Bearing model
Technical requirements
Material and hardness
Bearing rings adopt the provisions of
,| |tt||Tolerance grade is
bearing nominal inner diameter d
outer ring outer diameter with positive deviation value of magnetic motor bearing table
outer dimensions
B, CT
bearing steel, heat treatment quality should meet the requirements of
.
cage material should meet the requirements of product drawings. Bearing steel balls should meet the requirements of
inner drawing dimension tolerance and rotation accuracy according to table
outer ring dimension tolerance and rotation accuracy according to table
exceeding
upper deviation
upper deviation
lower deviation
lower deviation
upper deviation
lower deviation
lower deviation
lower deviation
lower deviation
.
requirements.
Upper deviation
Upper deviation
Upper deviation Lower deviation
Lower deviation
Lower deviation
Lower deviation
With the same bearing inner ring ≥B,
Bearing width tolerance according to the provisions of the table.
Upper deviation
Lower deviation
Upper deviation Lower deviation
Radial clearance
The radial clearance of the bearing shall comply with the provisions of the table
Assembly chamfer limit
Bearing assembly chamfer limit according to the provisions of
. According to the provisions of
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The surface roughness of the matching surface and end face
The surface roughness of the matching surface and end face of the bearing shall be according to the residual magnetism value
The residual magnetism value of the bearing shall not be greater than
If the user has other requirements, they can negotiate with the manufacturer to determine. Measuring method
Measurement of bearing size tolerance and rotation accuracy is measured by special instruments according to the bearing radial clearance. Measurement of surface roughness of bearing mating surface and end face is measured according to the bearing residual magnetism value according to
Inspection rules
Inspection rules of bearings are according to the provisions of
To check items
,
upper deviation
radial play
provisions.
provisions.
provisions. Use general inspection level II, main inspection items are shown in the table
lower deviation
main inspection items
inner diameter deviation and variation
outer diameter deviation and variation (D
meridian clearance
dV, V
AD, V
rotation accuracy
(K,, S, S, S, S)
bearing width deviation
bearing marking according to
bearing packaging according to
specified.
specified.
secondary inspection Items
Inner and outer ring width deviation and variation (4B, V, 4C, V residual magnetism
Assembly chamfer limit
Surface roughness of mating surface and surface
Appearance quality
Marking and packaging
People's Republic of China
Mechanical industry standards
Rolling bearings, magnetic motors and bearings
Published and distributed by the Machinery Standardization Research Institute of the Ministry of Machinery Industry Printed by the Machinery Standardization Research Institute of the Ministry of Machinery Industry (Beijing Taiti South Road
First edition in
First printing in
Cost
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