ISO 19259:2021
(Main)Plain bearings — Bearings with embedded solid lubricants
Plain bearings — Bearings with embedded solid lubricants
This document specifies a bearing with embedded solid lubricants, which has been widely used as a solid lubricant bearing.
Paliers lisses — Paliers avec lubrifiants solide incorporé
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 19259
Second edition
2021-10
Plain bearings — Bearings with
embedded solid lubricants
Paliers lisses — Paliers avec lubrifiants solide incorporé
Reference number
© ISO 2021
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ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Characteristics . 1
4.1 Structure . 1
4.2 Friction and wear characteristics . 3
4.3 Applicable field . 3
5 Material. 4
5.1 Metallic base body . 4
5.1.1 General . 4
5.1.2 Copper alloy castings . 4
5.1.3 Grey cast irons . 4
5.2 Solid lubricant . 5
5.3 Combination of metallic base body and solid lubricant . 5
6 Dimensions .5
7 Assembling . 8
8 Surface finish .9
Annex A (informative) Guide for selection of a bearing with embedded solid lubricants .10
Annex B (informative) Actual applications of a bearing with embedded solid lubricants .11
Bibliography .12
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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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 19259:2015), of which it constitutes a
minor revision.
The main changes are as follows:
— editorial update.
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 19259:2021(E)
Plain bearings — Bearings with embedded solid lubricants
1 Scope
This document specifies a bearing with embedded solid lubricants, which has been widely used as a
solid lubricant bearing.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 185, Grey cast irons — Classification
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 Characteristics
4.1 Structure
A bearing with embedded solid lubricants is composed of a metallic base body supporting a load and
a solid lubricant embedded in holes or hollows formed on the surface of the metallic base body giving
lubricity. As to the embedded state of a solid lubricant, there is a plug type and a spiral type (see
Figure 1).
As for hole type, there are “through” or perforated ones and “bottomed” ones (see Figure 2).
This document specifies a type which is most common and has been widely used where a solid lubricant
of a plug type is embedded in through holes. This document also specifies a cylindrical bush and a
flanged bush (see Figure 3).
a) Plug type b) Spiral type
Figure 1 — Embedded state of solid lubricants on cylindrical bush
a) Through hole type b) Bottomed hole type
Key
1 metallic base body
2 hole
3 solid lubricant plug
Figure 2 — Structure of cross section on a bearing with embedded solid lubricants
a) Cylindrical bush b) Flanged bush
Figure 3 — Overview of a bearing with embedded solid lubricants (plug type)
4.2 Friction and wear characteristics
A bearing with embedded solid lubricants falls under the category of a solid lubricant bearing among
self-lubricating bearings. In the solid lubricant bearings, there is a solid type, a coated type, a dispersed
type, and an embedded type.
A solid type is such where a solid lubricant powder is solidified using pitch, resin or the like as a binder.
A coated type is such where a solid lubricant film is formed on a sliding surface by chemical or physical
means such as coating, baking, chemical reaction, or the like.
A dispersed type is such where a solid lubricant powder (fine particles) is dispersed into sintered metal
matrix or the like.
An embedded type is such as mentioned above where holes or hollows are formed on a sliding surface
of a metallic base body and solid lubricants are embedded therein and, since the load is supported by a
metallic base body, this type has excellent load carrying capacity.
The embedded solid lubricant supplies solid lubricant to the sliding surface and, when it slides on
the mating member, the solid lubricant is properly drawn out and spread over both sliding surfaces
whereupon a solid lubricant film is formed.
Further, even when the film is broken, the embedded solid lubricant is drawn out by friction onto the
sliding surfaces, so it repairs the film on the sliding surfaces whereby the lubrication is made possible
for long periods and long life is achieved (see Figure 4).
Since the types of metallic base body and solid lubricant can be appropriately selected depending upon
the operating conditions, a wide range of applications is possible. Moreover, bearings ranging from
small to large sizes can be manufactured.
Key
1 metallic base body
2 mating member
3 embedded solid lubricant
4 solid lubricant film
A sliding direction
Figure 4 — Lubricating mechanism of a bearing with embedded solid lubricants
4.3 Applicable field
The bearing can be used for rotational motion, reciprocating motion, oscillating motion, and frequent
start/stop cycles. The bearing is also used in such applications where no fluid lubrication can be
expected because of high load and low speed operation, and where the environment temperature is
high.
Principally, the bearing can be used without supplying oil or grease. However, depending upon the
actual operating conditions, oil or grease may be supplied for a purpose of enhancement of durability,
removal of wear particulate or dust, and prevention of corrosion of the mating member.
5 Material
5.1 Metallic base body
5.1.1 General
Principal materials used as a metallic base body in which the solid lubricant is embedded include high
strength cast brass, cast bronze, cast aluminium bronze, and grey cast iron.
5.1.2 Copper alloy castings
Chemical compositions of copper alloy castings used as the metallic base body are shown in Table 1.
Table 1 — Chemical composition of copper alloy castings for a bearing
with embedded solid lubricants
Chemical composition
mass fraction, %
Chemical element
High strength brass Bronze I Bronze II Aluminium bronze
CuZn25Al6Mn4Fe3 CuSn10Zn2 CuPb5Sn5Zn5 CuAl10Fe5Ni5
Components
Cu 60,0 to 65,0 86,5 to 89,5 83,0 to 87,0 78,0 to 85,0
Sn 9,0 to 11,0 4,0 to 6,0
Pb 4,0 to 6,0
Zn 22,0 to 28,0 1,0 to 3,0 4,0 to 6,0
Fe 2,0 to 4,0 3,0 to 6,0
Ni 3,0 to 6,0
Al 5,0 to 7,5 8,5 to 10,5
Mn 2,5 to 5,0 0,1 to 1,5
Impurity
Sn ≤0,2 ≤0,1
Pb ≤0,2 ≤1,0 ≤0,1
Zn ≤0,5
Fe ≤0,2 ≤0,3
Sb ≤0,2 ≤0,2
Ni ≤0,5 ≤1,0 ≤1,0
a a
P ≤0,05 ≤0,05
Al ≤0,01 ≤0,01
Si ≤0,1 ≤0,01 ≤0,01
a
For permanent mould castings, centrifugal castings using mould and continuous castings, phosphorus content shall be
0,5 % maximum.
5.1.3 Grey cast irons
Grey cast irons used as the metallic base body shall conform to ISO 185.
5.2 Solid lubricant
Table 2 shows outlines of the application and the operating temperature of solid lubricants of a
graphite-base type and a fluororesin-base type, which are representative ones of the solid lubricant to
be embedded in the metallic base body. Besides those, there are sulfide-base type such as molybdenum
disulfide and tungsten disulfide used under special and extreme circumstances. Each of them is used as
sole component or as a mixed component with other additives. The additives compounded with each of
those types are specified by manufacturers.
Table 2 — Types of solid lubricants and their applications
Operating temperature
Type Applications
°C
General-purpose use
Graphite-base −40 to 400
High temperature use
General-purpose use
Fluororesin-base −40 to 80
Underwater use
Generally, a solid lubricant plug is formed in such a manner that the solid lubricant powder comprising
the single component or the mul
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