U.S. patent application number 13/064711 was filed with the patent office on 2011-08-04 for solid lubricant and sliding member.
This patent application is currently assigned to OILES CORPORATION. Invention is credited to Takuya Hirayama, Masayuki Rokugawa.
Application Number | 20110190178 13/064711 |
Document ID | / |
Family ID | 33447136 |
Filed Date | 2011-08-04 |
United States Patent
Application |
20110190178 |
Kind Code |
A1 |
Rokugawa; Masayuki ; et
al. |
August 4, 2011 |
Solid lubricant and sliding member
Abstract
Lead-free solid lubricant to be embedded in pores or grooves
formed at a sliding surface of a sliding member body, comprising 20
to 40% by weight of at least one wax selected from hydrocarbon
waxes, higher-fatty acids, esters of higher-fatty acid and amides
of higher-fatty acid, 20 to 40% by weight of melamine cyanurate,
and 20 to 50% by weight of a polytetrafluoroethylene resin. The
lubricant exhibits sliding properties identical to or higher than
those of lead-containing solid lubricants, even under high load
conditions.
Inventors: |
Rokugawa; Masayuki;
(Fujisawa-shi, JP) ; Hirayama; Takuya;
(Fujisawa-shi, JP) |
Assignee: |
OILES CORPORATION
Tokyo
JP
|
Family ID: |
33447136 |
Appl. No.: |
13/064711 |
Filed: |
April 11, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10556077 |
Aug 16, 2006 |
|
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PCT/JP2004/006028 |
May 7, 2004 |
|
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13064711 |
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Current U.S.
Class: |
508/181 |
Current CPC
Class: |
C10M 2215/08 20130101;
C10M 2215/221 20130101; C10M 2205/163 20130101; C10M 2215/14
20130101; C10N 2050/08 20130101; C10M 169/04 20130101; C10M
2205/022 20130101; C10M 2207/401 20130101; C10M 2213/062 20130101;
C10M 2205/16 20130101; C10M 2223/02 20130101; C10M 2213/0623
20130101; C10M 2207/1253 20130101; C10M 2215/0806 20130101; F16C
33/10 20130101; C10M 2207/125 20130101; C10M 2207/40 20130101; C10N
2030/06 20130101 |
Class at
Publication: |
508/181 |
International
Class: |
C10M 177/00 20060101
C10M177/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 13, 2003 |
JP |
2003-133923 |
Claims
1.-5. (canceled)
6. A method of making a solid lubricant for embedding in pores or
grooves formed at a sliding surface of a sliding member body, the
method comprising the steps of: (a) blending together 20 to 40% by
weight of at least one wax selected from the group consisting of
hydrocarbon waxes, higher-fatty acids, esters of higher-fatty acid
and amides of higher-fatty acid, 20 to 40% by weight of melamine
cyanurate, and 20 to 50% by weight of a polytetrafluoroethylene
resin to form a mixture devoid of lead and graphite, and thereafter
(b) injection molding the mixture formed in step (a) to form
cylindrical solid lubricant pieces.
7. The method of forming solid lubricant pieces formed by the
process of claim 6, wherein the mixture formed in step (a) further
contains from 5 to 20% by weight of metal soap.
8. The method of forming solid lubricant pieces formed by the
process of claim 6, wherein the mixture formed in step (a) further
contains from 5 to 20% by weight of a polyethylene resin.
9. The method of forming solid lubricant pieces formed by the
process of claim 6, wherein the mixture formed in step (a) further
contains from 5 to 15% by weight of a phosphate.
10. A method of forming solid lubricant pieces formed by the
process of claim 6, including the additional step of: (c) injection
molding the extruded pellets formed in step (b) to form cylindrical
solid lubricant pieces in a desired shape.
Description
[0001] This application is a divisional of application Ser. No.
10/556,077 filed Aug. 16, 2006, which in turn is the US national
phase of international application PCT/JP2004/006028 filed 7 May
2004, which designated the U.S. and claims priority to JP
2003-133923 filed 13 May 2003, the entire contents of each of which
are hereby incorporated by reference.
TECHNICAL FIELD
[0002] The present invention relates to a solid lubricant and a
sliding member, and more particularly, to a solid lubricant for
being embedded in pores or grooves formed at a sliding surface of a
sliding member body and a sliding member therefrom.
BACKGROUND ART
[0003] Solid lubricants which are embedded at a sliding surface of
a sliding member such as bearings, form a thin film on the sliding
surface and exhibit a sliding effect. Therefore, a film-forming
capability of the solid lubricants has a large influence on
friction coefficient and life of the resultant film. As such solid
lubricants, there are known solid lubricants having lamellar
structures, especially, a solid lubricant containing graphite as a
main component. The graphite exhibits a large resistivity in the
direction of load applied thereto, but exhibits a small resistivity
in the sliding direction caused by the lamellar structure.
Furthermore, the graphite is a soft and able to keep good
lubrication performance over a broad temperature range of from an
ordinary temperature to a high temperature.
[0004] The solid lubricant containing graphite as a main component,
however, tends to be not only insufficient in film-forming
capability to some extent, but also unsatisfactory in film life
when repeatedly exposed to frictional contact. Therefore, such
solid lubricant is not suitable for use in low-speed and high-load
applications.
[0005] While, as solid lubricants used in high-load applications,
there are exemplified a solid lubricant prepared by blending a
polytetrafluoroethylene resin, a wax, a soft metal such as indium,
lead and tin with each other. Especially, a solid lubricant
prepared by blending polytetrafluoroethylene resin with lead and a
wax is widely used. Such solid lubricant exhibits an extremely low
coefficient of friction under high-load conditions, an excellent
film-forming capability, a long film life and a high self-repairing
ability for the film.
[0006] Recently, lead-free materials tend to be developed in the
consideration of avoiding environmental problems. This tendency of
the material development has also been present in the field of
solid lubricants. However, in the solid lubricants, lead is an
important component for attaining satisfactory sliding properties
of solid lubricants. Particularly, in the case where the solid
lubricant are embedded in pores or grooves formed at the sliding
surface of a sliding member such as bearings and used under
high-load conditions, lead is important from the standpoint of
imparting a good film-forming capability.
[0007] As an example of a lead-free sliding member, there is
described the sliding member produced by molding a resin containing
an adduct of melamine and isocyanuric acid (Japanese Patent
Application Laid-Open (KOKAI) No. 55-108427). In the case where the
resin composition for the sliding member containing the adduct of
melamine and isocyanuric acid is used as a solid lubricant, the
coefficient of friction tends to be insufficient under high-load
conditions. Therefore, it has been demanded to provide a lead-free
solid lubricant exhibiting sufficient sliding properties even under
high-load conditions.
DISCLOSURE OF THE INVENTION
Problem to be Solved of the Invention
[0008] The present invention has been conducted for solving the
above-described problems. The object of the present invention is to
provide a lead-free solid lubricant capable of exhibiting sliding
properties which are identical to or higher than those of
conventional lead-containing solid lubricants, even under high-load
conditions.
Means for Solving the Problem
[0009] In a first aspect of the present invention, there is
provided a solid lubricant for being embedded in pores or grooves
formed at the sliding surface of a sliding member body, and
comprising 20 to 40% by weight of at least one wax selected from
the group consisting of hydrocarbon-based waxes, higher-fatty
acids, esters of higher-fatty acid and amides of higher-fatty acid,
20 to 40% by weight of melamine cyanurate and 20 to 50% by weight
of a polytetrafluoroethylene resin.
[0010] In a second aspect of the present invention, there is
provided a sliding member comprising a sliding member body having a
sliding surface, and the above solid lubricant which is embedded in
pores and grooves formed at the sliding surface of the sliding
member body.
Effect of the Invention
[0011] According to the present invention, there is provided a
lead-free solid lubricant for being embedded in pores or grooves
formed at a sliding surface of a sliding member body, which is
identical to or higher than those of conventional lead-containing
solid lubricants, even under high-load conditions.
BEST MODE FOR CARRYING OUT THE INVENTION
[0012] The embodiments of the present invention are described in
detail below. First, a solid lubricant is described. The wax has an
effect for lowering a coefficient of friction. The wax used in the
present invention is one or more of waxes selected from the group
consisting of hydrocarbon-based waxes, higher-fatty acids, esters
of higher-fatty acid and amides of higher-fatty acid.
[0013] The hydrocarbon-based waxes may include parafinic waxes
having not less than 24 carbon atoms, olefinic waxes having not
less than 26 carbon atoms, alkylbenzenes having not less than 28
carbon atoms and crystalline micro crystalline waxes. These
hydrocarbon-based waxes may be used singly or in the form of a
mixture of any two or more thereof.
[0014] The higher-fatty acids may include saturated or unsaturated
fatty acids having not less than 12 carbon atoms. Specific examples
of the higher-fatty acids may include lauric acid, myristic acid,
palmitic acid, stearic acid, arachic acid, behenic acid, cerotic
acid, montanic acid, melissic acid, lauroleic acid, myristoleic
acid, oleic acid, elaidic acid, linolic acid, linolenic acid,
arachidonic acid, gadoleic acid and erucic acid.
[0015] The esters of higher-fatty acid are esters of the above
higher-fatty acids with monohydric or polyhydric alcohols. Examples
of the monohydric alcohols may include capryl alcohol, lauryl
alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol and
behenyl alcohol. Examples of polyhydric alcohols may include
ethylene glycol, propylene glycol, butane diol, glycerol,
pentaerythritol and sorbitan. Specific examples of the esters of
higher-fatty acid may include stearyl stearate, pentaerithritol
tetrastearate, stearic monoglyceride and behenic monoglyceride.
[0016] The amides of higher-fatty acid are amides of the above
higher-fatty acids with monoamines or polyamines. Examples of
monoamines or polyamines may include capryl amine, lauryl amine,
myristyl amine, palmityl amine, stearyl amine, methylenediamine,
ethylenediamine and hexamethylenediamine. Specific examples of the
amides of higher-fatty acid may include palmitamide, stearamide,
oleamide and erucamide.
[0017] The amount of waxes blended is usually from 20 to 40% by
weight, preferably from 20 to 30% by weight. When the amount of the
waxes is less than 20% by weight, the resultant solid lubricant may
fail to show the aimed low friction characteristics. When the
amount of the waxes exceeds 40% by weight, the resultant solid
lubricant tends to be deteriorated in moldability, and the molded
product obtained therefrom tends to be deteriorated in
strength.
[0018] The melamine cyanurate used is an adduct of melamine with
cyanuric acid or isocyanuric acid. The melamine cyanurate has such
a structure that the melamine molecules having a 6-membered ring
structure and cyanuric acid (or isocyanuric acid) molecules having
a 6-membered ring structure are arranged in plane through a
hydrogen bond to form overlapped layers bonded to each other by a
weak bonding force. Therefore, it is considered that the melamine
cyanurate show a cleavage property similar to molybdenum disulfide
or graphite. The melamine cyanurate has an effect of improving a
wear resistance and a load-carrying capacity of the solid
lubricant. The amount of the melamine cyanurate blended is usually
from 20 to 40% by weight, preferably from 30 to 40% by weight. When
the amount of the melamine cyanurate blended is less than 20% by
weight, it may be difficult to obtain the aimed effect of enhancing
a wear resistance and a load-carrying capacity. When the amount of
the melamine cyanurate blended exceeds 40% by weight, the resultant
solid lubricant tends to be deteriorated in wear resistance.
[0019] The polytetrafluoroethylene (PTFE) resins used in the
present invention have an effect for improving low friction
properties. The polytetrafluoroethylene resins used in the present
invention may be classified to (1) polytetrafluoroethylene resins
which are mainly used for molding as molding powder or fine powder
(hereinafter referred to as "high molecular weight PTFE"), and (2)
polytetrafluoroethylene resins which are mainly used for additives,
which are easy to pulverize and exhibit a good dispersibility
(hereinafter referred to as "low molecular weight PTFE"), in which
the molecular weight of the polytetrafluoroethylene resin is
lessened as compared with the high molecular weight PTFE by
decomposing the high molecular weight PTFE by mean of radiation
exposure, or by controlling the molecular weight upon the
polymerization of the polytetrafluoroethylene resin. As the
polytetrafluoroethylene resin used in the present invention, the
high molecular weight PTFE itself or a mixture of high molecular
weight PTFE and low molecular weight PTFE may be used. The mixing
ratio (by weight) of the high molecular weight PTFE to the low
molecular weight PTFE is usually from 1:1 to 3:1.
[0020] The high molecular weight PTFE for the molding powder may
include "TEFLON (registered trademark) 7-J", "TEFLON (registered
trademark) 7A-J", "TEFLON (registered trademark) 70-J", all
produced by Du Pont-Mitsui Fluorochemical Co., Ltd.; "POLYFLON M-12
(tradename)" produced by Daikin Industries, Ltd.; "FLUON G-163
(tradename)", "FLUON G-190 (tradename)", both produced by Asahi
Glass Co., Ltd., or the like. The high molecular weight PTFE for
the fine powder may include "TEFLON (registered trademark) 6CJ"
produced by Du Pont-Mitsui Fluorochemical Co., Ltd.; "POLYFLON F201
(tradename)" produced by Daikin Industries, Ltd.; and "FLUON CD076
(tradename)", "FLUON CD090(tradename)", both produced by Asahi
Glass Co., Ltd., or the like.
[0021] Further, as the high molecular weight PTFE, there are
exemplified high molecular weight PTFEs modified with polymers such
as polystyrene-based polymers, acrylic acid ester-based polymers,
methacrylic acid ester-based polymers and acrylonitrile-based
polymers other than the above-mentioned high molecular weight PTFE.
For example, "METABLEN A-3000 (tradename) " produced by Mitsubishi
Rayon Co., Ltd. or the like exemplified. Examples of the low
molecular weight PTFE may include "TLP-10F (tradename)" produced by
Du Pont-Mitsui Fluorochemical Co., Ltd.; "LUBLON L-5 (tradename)"
produced by Daikin Industries, Ltd.; and "FLUON L169J (tradename)"
produced by Asahi Glass Co., Ltd.; and "KTL-8N (tradename) etc. by
Kitamura Limited.
[0022] The amount of polytetrafluoroethylene resin blended is
usually from 20 to 50% by weight, preferably from 20 to 40% by
weight. When the amount of polytetrafluoroethylene resin is less
than 20% by weight, it is difficult to obtain the aimed low
friction properties. When the amount of polytetrafluoroethylene
resin exceeds 50% by weight, the resultant solid lubricant tends to
be deteriorated in wear resistance and shape-keeping ability, and
the molded products obtained therefrom tend to be deteriorated in
strength.
[0023] In the present invention, a metallic soap and/or a
polyethylene resin and/or a phosphate may be added to the solid
lubricant as additives.
[0024] The metallic soaps used in the present invention are a salt
of above-described higher-fatty acid with alkali metal or alkali
earth metal. Examples of the metallic soaps may include lithium
stearate and calcium stearate. These metallic soaps have an effect
of not only increasing a wear resistance and decreasing a
coefficient of friction but also improving a thermal stability. The
amount of metallic soap blended is usually from 5 to 20% by weight,
preferably from 10 to 15% by weight. When the amount of the
metallic soap is less than 5% by weight, it may be difficult to
obtain the aimed effect of decreasing a friction coefficient, and
improving the wear resistance and thermal stability. When the
amount of the metallic soap blended exceeds 20% by weight, the
resultant solid lubricant tends to be deteriorated in
moldability.
[0025] The polyethylene resins used in the present invention have
an effect of improving a wear resistance and binding forces among
ingredients of solid lubricant. The polyethylene resins used in the
present invention may include a high pressure-processed low density
polyethylene (HPLD), a linear low density polyethylene (LLDPE), a
very low density polyethylene (VLDPE), a high density polyethylene
(HDPE), an ultra high molecular weight polyethylene (UHMWPE) and a
high molecular weight polyethylene (HMWPE) composed of the ultra
high molecular weight polyethylene and polyethylene having from low
molecular weight to high molecular weight.
[0026] The HPLD is a homopolymer of ethylene produced by
high-pressure process, and contains long branched chains in
addition to short branched chains such as ethyl group. The density
of the HPLD is usually from 0.910 to 0.940 g/cm.sup.3. The LLDPE is
a copolymer of ethylene and other .alpha.-olefin (propylene,
butene-1, 4-methyl pentene-1, octene-1 or the like), which is
produced by medium or low-pressure process, and has a density of
usually from 0.900 to 0.940 g/cm.sup.3. Of these copolymers,
copolymers having density of usually from 0.925 to 0.940 g/cm.sup.3
are called as a medium density polyethylene (MDPE). The VLDPE is
obtained by further decreasing the density of LLDPE and has a
density of usually from 0.880 to 0.910 g/cm.sup.3. The HDPE is a
homopolymer of ethylene produced by medium or low-pressure process,
and has density of usually from 0.940 to 0.970 g/cm.sup.3. The
UHMWPE is a polyethylene produced by low-pressure process, and has
a molecular weight of usually not less than 100 million and a
density of usually about 0.940 g/cm.sup.3.
[0027] The amount of polyethylene resin blended is usually from 5
to 20% by weight, preferably from 10 to 15% by weight. When the
amount of the polyethylene resin blended is less than 5% by weight,
the polyethylene resin may fail to exhibit a sufficient effect as a
binder. When the amount of the polyethylene resin blended exceeds
20% by weight, the amounts of each ingredients for producing the
solid lubricant are comparatively small, so that it is difficult to
obtain a good lubrication property.
[0028] As the phosphates, there may be exemplified tertiary
phosphates, secondary phosphates, pyrophosphates, phosphites and
metaphosphates of alkali metals or alkalie earth metal. Examples of
the phosphates may include trilithium phosphate, dilithium
hydrogenphosphate, lithium pyrophosphate, tricalcium phosphate,
calcium monohydrogenphosphate, calcium pyrophosphate, lithium
metaphosphate, magnesium metaphosphate and calcium metaphosphate.
Although phosphates themselves do not show a lubrication property,
phosphates exhibit an effect of promoting the formation of
lubrication film on a surface of the mating member upon sliding
thereon, so that it is possible to always form and keep good
lubrication film on the surface of the mating member, thereby
maintaining good sliding properties.
[0029] The amount of phosphates blended is usually from 5 to 15% by
weight, preferably from 10 to 15% by weight. When the amount of the
phosphates blended is less than 5% by weight, the phosphates may
fail to exhibit a sufficient effect of promoting the formation of
lubrication film on the surface of the mating member. When the
amount of phosphates blended exceeds 20% by weight, the amount of
lubrication film transferred and attached on the surface of the
mating member tend to be excessively large, so that the resultant
sliding member tends to be deteriorated in wear resistance.
[0030] The solid lubricant of the present invention can be produced
by mixing the above respective components with each other at a
predetermined mixing ratio using mixers such as a Henschel mixer, a
Super mixer, a ball mill and a tumbler, and then molding the
resultant mixture into a desired shape. The molding method is not
particularly limited, but there may be usually used such a molding
method in which the obtained mixture is supplied to an extruder and
melt-kneaded therein at a temperature capable of melting the waxes
to prepare pellets, and then the obtained pellets are supplied to
an injection-molding machine and injection-molded therefrom.
[0031] The sliding member of the present invention is produced by
embedding the solid lubricant obtained by the above-described
process into pores or grooves formed at the sliding surface of the
sliding member body composed of metals or synthetic resins.
Examples of the method of embedding the solid lubricant into pores
or grooves formed at the sliding surface of the sliding member body
may include a press fitting method and adhesive fitting method of
applying an adhesive on the surface of the molded solid lubricant
and puts the resultant solid lubricant into the pores or
grooves.
EXAMPLES
[0032] The present invention is described in more detail by
Examples, but the Examples are only illustrative and not intended
to limit the scope of the invention.
Example 1
[0033] 50% by weight of high molecular weight PTFE ("FLUON G163
(tradename)" produced by Asahi Glass Co., Ltd.) as
polytetrafluoroethylene resin, 10% by weight of polyethylene wax
("LICOWAX PE520 (tradename)" produced by Clariant Japan
Corporation), 10% by weight of paraffin wax ("150 (tradename)"
produced by Nippon Seiro Co., Ltd.) as hydrocarbon-based wax and
30% by weight of melamine cyanurate ("MCA (tradename)" produced by
Mitsubishi Chemical Corporation) were introduced into Henschel
mixer and mixed with each other therein to produce a mixture. The
obtained mixture was introduced into an extruder and melt-kneaded
therein to obtain a string-shaped molding. The obtained
string-shaped molding was cut to fine pieces to produce pellets
composed of the mixture. Then, the obtained pellets were supplied
to an injection-molding machine and injection-molded to obtain a
cylindrical solid lubricant having a diameter of 6 mm and a length
of 5 mm.
Examples 2 to 23 and Comparative Examples 1 and 3
[0034] The same procedure as defined in Example 1 was conducted
except that the composition was variously changed as shown in
Tables 2 to 8, thereby obtaining cylindrical solid lubricants
having a diameter of 6 mm and a length of 5 mm.
Comparative Example 2
[0035] 50% by volume of PTFE powder ("TEFLON (registered trademark)
7A-J" produced by Du Pont-Mitsui Fluorochemical Co., Ltd.) and 40%
by volume of atomized lead powder were mixed and stirred to obtain
a mixture. The resultant mixture was pressure-molded to produce a
cylindrical solid lubricant having a diameter of 6 mm and a length
of 5 mm, using a pressure-molding machine. The obtained cylindrical
solid lubricant was dipped in lubricating oil solution ("DTE extra
heavy oil (tradename) produced by Mobile Co., Ltd.) in an oil bath
to impregnate 10% by volume of the lubricating oil, thereby
obtaining a solid lubricant containing the PTFE of 18.8% by weight,
lead of 79.6% by weight and lubricating oil of 1.6% by weight.
[0036] The solid lubricant obtained from above-described examples
or comparative examples were embedded in pores formed at the
sliding surface of a plane body composed of cupper alloy to prepare
specimens for sliding member test. The obtained test specimens were
subjected to thrust test to measure the sliding properties. The
testing conditions are shown in Table 1. The obtained sliding
properties are shown in Tables 2 to 8.
TABLE-US-00001 TABLE 1 Material of test specimen High strength
brass fourth-class casting Material of mating member Stainless
steel (SUS403) Area ratio occupied by solid 30% lubricant in
sliding surface of specimen Sliding velocity 0.5 m/min Load 300
kgf/cm.sup.2 Lubrication None Testing time 10 hr
TABLE-US-00002 TABLE 2 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Composition PTFE
High Molecular 50 40 30 50 Weight PTFE Low Molecular Weight -- --
-- -- PTFE Waxes Hydrocarbon-based Waxes Polyethylene wax 10 10 15
-- Paraffin wax 10 10 15 -- Micro crystalline wax -- -- -- 20
Higher-fatty acid Stearic acid -- -- -- -- Melamine cyanurate 30 40
40 30 Metallic soap Lithium stearate -- -- -- -- Zinc stearate --
-- -- -- Calcium stearate -- -- -- -- Polyethylene Resin HDPE -- --
-- -- LDPE -- -- -- -- HMWPE -- -- -- -- Phosphates Calcium
pyrophosphate -- -- -- -- Tricalcium phosphate -- -- -- -- Various
properties Friction coefficient 0.072- 0.086- 0.088- 0.078- 0.085
0.093 0.096 0.088 Wear amount (.mu.m) 4 4 4 4
TABLE-US-00003 TABLE 3 Ex. 5 Ex. 6 Ex. 7 Ex. 8 Composition PTFE
High Molecular 25 20 15 25 Weight PTFE Low Molecular Weight 25 20
15 25 PTFE Waxes Hydrocarbon-based Waxes Polyethylene wax 10 10 15
-- Paraffin wax 10 10 15 -- Micro crystalline wax -- -- -- 20
Higher-fatty acid Stearic acid -- -- -- -- Melamine cyanurate 30 40
40 30 Metallic soap Lithium stearate -- -- -- -- Zinc stearate --
-- -- -- Calcium stearate -- -- -- -- Polyethylene Resin HDPE -- --
-- -- LDPE -- -- -- -- HMWPE -- -- -- -- Phosphates Calcium
pyrophosphate -- -- -- -- Tricalcium phosphate -- -- -- -- Various
properties Friction coefficient 0.086- 0.092- 0.093- 0.090- 0.094
0.100 0.110 0.098 Wear amount (.mu.m) 4 4 4 4
TABLE-US-00004 TABLE 4 Ex. 9 Ex. 10 Ex. 11 Composition PTFE High
Molecular 20 30 40 Weight PTFE Low Molecular Weight -- -- -- PTFE
Waxes Hydrocarbon-based Waxes Polyethylene wax 15 10 10 Paraffin
wax 15 10 10 Micro crystalline wax -- -- -- Higher-fatty acid
Stearic acid 10 10 10 Melamine cyanurate 40 40 30 Metallic soap
Lithium stearate -- -- -- Zinc stearate -- -- -- Calcium stearate
-- -- -- Polyethylene Resin HDPE -- -- -- LDPE -- -- -- HMWPE -- --
-- Phosphates Calcium pyrophosphate -- -- -- Tricalcium phosphate
-- -- -- Various properties Friction coefficient 0.073- 0.088-
0.073- 0.085 0.097 0.085 Wear amount (.mu.m) 0.5 1 3
TABLE-US-00005 TABLE 5 Ex. 12 Ex. 13 Ex. 14 Ex. 15 Composition PTFE
High Molecular 20 20 20 20 Weight PTFE Low Molecular Weight -- --
-- -- PTFE Waxes Hydrocarbon-based Waxes Polyethylene wax 30 15 --
-- Paraffin wax -- 15 30 -- Micro crystalline wax -- -- -- 30
Higher-fatty acid Stearic acid -- -- -- -- Melamine cyanurate 40 40
40 40 Metallic soap Lithium stearate 10 -- -- -- Zinc stearate --
10 -- -- Calcium stearate -- -- 10 10 Polyethylene Resin HDPE -- --
-- -- LDPE -- -- -- -- HMWPE -- -- -- -- Phosphates Calcium
pyrophosphate -- -- -- -- Tricalcium phosphate -- -- -- -- Various
properties Friction coefficient 0.094- 0.088- 0.080- 0.083- 0.096
0.095 0.085 0.087 Wear amount (.mu.m) 2 2 1 1
TABLE-US-00006 TABLE 6 Ex. 16 Ex. 17 Ex. 18 Ex. 19 Composition PTFE
High Molecular 20 20 20 20 Weight PTFE Low Molecular Weight -- --
-- -- PTFE Waxes Hydrocarbon-based Waxes Polyethylene wax 10 15 --
-- Paraffin wax 10 15 20 -- Micro crystalline wax -- -- -- 20
Higher-fatty acid Stearic acid 10 10 10 10 Melamine cyanurate 40 30
40 40 Metallic soap Lithium stearate -- -- -- -- Zinc stearate --
-- -- -- Calcium stearate -- -- -- -- Polyethylene Resin HDPE 10 --
-- -- LDPE -- 10 10 -- HMWPE -- -- -- 10 Phosphates Calcium
pyrophosphate -- -- -- -- Tricalcium phosphate -- -- -- -- Various
properties Friction coefficient 0.092- 0.086- 0.094- 0.096- 0.100
0.098 0.110 0.120 Wear amount (.mu.m) 1 1 2 2
TABLE-US-00007 TABLE 7 Ex. 20 Ex. 21 Ex. 22 Ex. 23 Composition PTFE
High Molecular 20 20 20 20 Weight PTFE Low Molecular Weight -- --
-- -- PTFE Waxes Hydrocarbon-based Waxes Polyethylene wax 10 10 20
-- Paraffin wax 10 10 -- -- Micro crystalline wax -- -- -- 20
Higher-fatty acid Stearic acid 10 10 10 10 Melamine cyanurate 30 30
30 30 Metallic soap Lithium stearate -- -- -- -- Zinc stearate --
-- -- -- Calcium stearate -- -- -- -- Polyethylene Resin HDPE 10 --
-- -- LDPE -- 10 10 -- HMWPE -- -- -- -- Phosphates Calcium
pyrophosphate 10 10 -- 10 Tricalcium phosphate -- -- 10 -- Various
properties Friction coefficient 0.076- 0.074- 0.084- 0.086- 0.080
0.082 0.098 0.096 Wear amount (.mu.m) 4 3 3 4
TABLE-US-00008 TABLE 8 Comp. Comp. Comp. Ex. 1 Ex. 2 Ex. 3
Composition PTFE High Molecular -- 18.8 50 Weight PTFE Low
Molecular 10.5 -- -- Weight PTFE Waxes Hydrocarbon Waxes Paraffin
wax 2 -- 40 Melamine cyanurate -- -- -- Metallic soap Lithium
stearate 1 -- 10 Polyethylene Resin LDPE 1.5 -- -- Lead 85 79.6 --
Lubricant oil -- 1.6 -- Various properties Friction coefficient
0.099-0.110 0.089-0.120 0.100-0.145 Wear amount (.mu.m) 2 8 35
[0037] In the above tables, as a low molecular weight PTFE, "LUBLON
L-5 (tradename)" produced by Daikin Industries, Ltd. was used; as a
microcrystalline wax, "HI-MIC-1080 (tradename)" produced by Nippon
Seiro Co., Ltd. was used; as a HDPE, "HIZEX (tradename) produced by
Mitsui Chemicals Corporation was used; as a LDPE, "FLO-THENE G701
(tradename)" produced by Sumitomo Seika Chemicals Co., Ltd. was
used; and as a HMWPE, "LUBMER (tradename)" produced by Mitsui
Chemicals Co. Ltd. was used.
[0038] As apparently recognized from the above results, it was
confirmed that the sliding member obtained by embedding the solid
lubricant of the present invention in the sliding surface of the
sliding member body showed excellent sliding properties under low
speed and high-load conditions, which sliding properties were
identical to or higher than those of the conventional sliding
member obtained by embedding the lead-containing solid lubricant
obtained in Comparative Examples 1 and 2. On the other hand, it was
confirmed that the sliding member obtained by embedding the
melamine cyanurate-free solid lubricant obtained in Comparative
Example 3, in the sliding surface of the sliding member body showed
the higher coefficient of friction and large wear amount, thereby
exhibiting poor sliding properties.
* * * * *