ISO 20054:2022

INTERNATIONAL ISO
STANDARD 20054
Second edition
2022-06
Plain bearings — Bearings containing
dispersed solid lubricants
Paliers lisses — Paliers contenant des lubrifiants solides dispersés
Reference number
© ISO 2022
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and units. 1
5 Characteristics . 1
5.1 Structure . 1
5.2 Lubricating mechanism . 3
5.3 Applicable field . 3
6 Material. 3
6.1 Metal matrix . 3
6.2 Solid lubricant . 4
6.3 Combination of metal matrix and solid lubricant. 4
7 Dimension . 5
7.1 General . 5
7.2 General dimension . 5
7.2.1 Seamless bush . 5
7.2.2 Wrapped bush . 7
7.3 Tolerance classes and limit deviations . 7
7.3.1 General . 7
7.3.2 Bearing fit . 7
7.3.3 Bearing clearance . 7
8 Assembling . 8
9 Surface finish .8
Annex A (informative) Guidance for selection of a bearing metal matrix for bearings
containing dispersed solid lubricants . 9
Annex B (informative) Actual applications of a bearing containing dispersed solid
lubricants .10
Bibliography .11
iii
Foreword
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electrotechnical standardization.
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described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 123, Plain bearings, Subcommittee SC 7,
Special types of plain bearings.
This second edition cancels and replaces the first edition (ISO 20054:2016), of which it constitutes a
minor revision.
The main changes are as follows:
— the titles of 5.2, 7.3.2 and 7.3.3 have been changed to more suitable ones;
— changes in the description in 7.1 have been made due to the above changes.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
INTERNATIONAL STANDARD ISO 20054:2022(E)
Plain bearings — Bearings containing dispersed solid
lubricants
1 Scope
This document specifies the characteristics, materials, dimensions, assembly and surface finish for a
bearing containing dispersed solid lubricants which is used as a solid lubricant bearing.
NOTE In the solid lubricant bearing among self-lubricating bearings there is a solid type, a coated type, an
embedded type and a dispersed type, which is specified by this document.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Symbols and units
See Table 1.
Table 1 — Symbols and units
Symbol Description Unit
B Width of the bush mm
D Inside diameter of the bush mm
i
D Outside diameter of the bush mm
o
x Surface roughness —
5 Characteristics
5.1 Structure
A bearing containing dispersed solid lubricants is made of sintered composite materials that contain
solid lubricants dispersed uniformly in the metal matrix and is manufactured by powder metallurgy
(see Figure 1).
This document includes multi-layered bearings with the sintered layer on a steel backing and both
seamless and wrapped bushes (see Figure 2).
Figure 3 shows a typical microstructure of the bearings containing dispersed solid lubricants. The
dispersed solid lubricants in the metal matrix vary in grain size and volume.
a) Seamless bush — Fine solid lubricants type b) Seamless bush — Coarse solid lubricants
type
Figure 1 — Overview of bearings containing dispersed solid lubricants that are single-layered
a) Seamless bush b) Wrapped bush
Key
1 sintered layer
2 steel backing
Figure 2 — Overview of bearings containing dispersed solid lubricants that are multi-layered
a) Fine solid lubricants type b) Coarse solid lubricants type
Key
1 metal matrix
2 dispersed solid lubricant
Figure 3 — Microstructure of a bearing containing dispersed solid lubricants
5.2 Lubricating mechanism
A bearing containing dispersed solid lubricants obtains its sliding performance from the self-lubricating
effects of solid lubricants and the mechanical strength of metal matrix.
The sliding performance and mechanical strength vary according to the volume of solid lubricants.
Higher sliding performance requires more solid lubricants, while higher mechanical strength requires
less solid lubricants.
Since solid lubricants are dispersed over the entire material, the bearings are particularly suitable for
extra low speed or micro-motion applications, minimising static friction to achieve smooth sliding at
the start of motion.
The solid lubricants are drawn out over both surfaces from the bearing material when it slides
against the mating surface, forming a solid lubricant film. As the solid lubricant film is consumed, it is
replenished from the bearing material to maintain a continuous film throughout the life of the product
(see Figure 4).
Key
1 mating member 3 dispersed solid lubricant
2 metal matrix 4 solid lubricant film
a
Sliding direction.
Figure 4 — Lubricating mechanism of a bearing containing dispersed solid lubricants
5.3 Applicable field
The bearing can
...