U.S. patent application number 09/749694 was filed with the patent office on 2001-08-23 for constant-velocity universal joint for propeller shaft.
This patent application is currently assigned to NTN CORPORATION. Invention is credited to Takabe, Shinichi.
Application Number | 20010016563 09/749694 |
Document ID | / |
Family ID | 18530957 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010016563 |
Kind Code |
A1 |
Takabe, Shinichi |
August 23, 2001 |
Constant-velocity universal joint for propeller shaft
Abstract
A constant-velocity joint for a propeller shaft is provided
which can be used with good durability without adding any organic
lead compound, which is high in the effect of suppressing
temperature rise of grease during high-speed rotation, and which
can prevent deterioration of the grease. It is a cross-groove type
constant-velocity joint in which the PCD clearance is negative and
a preload is imparted or any other constant-velocity joint for a
propeller shaft in which a grease containing the following
components (a), (b) and (g) or (a) to (g) as essential components
is sealed: (a) base oil (b) diurea type thickening agent expressed
by the following formula
R.sup.1NH--CO--NH--C.sub.6H.sub.4--p--CH.sub.2--C.sub.6H.sub.4--p--NH--CO--
-NHR.sup.2 (wherein R.sup.1 and R.sup.2 are the same or different
aryl or cyclohexyl groups having a carbon number of 6 or 7) (c)
molybdenum sulfurized dialkyl dithiocarbamate, molybdenum
sulfurized dialkyl dithiophosphate, or a mixture thereof, (d)
molybdenum disulfide, (e) Zinc dithiophosphate compound,
sulfur-nitrogen-family extreme-pressure agent or an
extreme-pressure agent in which both are mixed, (f)
phosphorus-free, sulfur-containing extreme-pressure agent, (g)
sulfur-containing organic tin compound.
Inventors: |
Takabe, Shinichi;
(Iwata-shi, JP) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1941 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
NTN CORPORATION
Shizuoka
JP
|
Family ID: |
18530957 |
Appl. No.: |
09/749694 |
Filed: |
December 28, 2000 |
Current U.S.
Class: |
508/364 ;
508/369; 508/375; 508/539; 508/552 |
Current CPC
Class: |
C10M 2215/026 20130101;
C10M 137/105 20130101; C10M 2219/022 20130101; C10M 2227/08
20130101; C10M 2219/068 20130101; C10M 2215/1026 20130101; C10M
2227/083 20130101; C10M 2215/121 20130101; C10M 2223/047 20130101;
C10N 2040/042 20200501; C10N 2040/046 20200501; C10N 2040/04
20130101; F16D 2300/06 20130101; C10M 139/06 20130101; C10M
2219/066 20130101; C10M 169/06 20130101; C10M 2227/082 20130101;
C10N 2010/04 20130101; C10N 2040/02 20130101; C10M 2227/081
20130101; C10M 2215/1013 20130101; F16D 3/223 20130101; F16D
2003/22309 20130101; C10M 2215/006 20130101; C10N 2010/12 20130101;
C10M 2219/083 20130101; C10M 2215/2275 20130101; C10N 2040/044
20200501; C10M 2223/045 20130101; C10M 2201/066 20130101; C10M
2215/2206 20130101; C10M 2219/082 20130101; C10M 2201/084 20130101;
C10M 135/18 20130101; C10M 2201/065 20130101; C10M 125/22 20130101;
C10M 137/10 20130101; C10M 115/08 20130101; C10M 2215/0813
20130101 |
Class at
Publication: |
508/364 ;
508/369; 508/375; 508/552; 508/539 |
International
Class: |
C10M 141/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 7, 2000 |
JP |
2000-1766 |
Claims
What is claimed is:
1. A constant-velocity joint for a propeller shaft in which a
grease containing the following components (a), (b) and (g) as
essential components is sealed: (a) base oil (b) diurea type
thickening agent expressed by the following formula
R.sup.1NH--CO--NH--C .sub.6H.sub.4--p--CH.sub.2--C
.sub.6H.sub.4--p--NH--CO--NHR.sup.2 (wherein R.sup.1 and R.sup.2
are the same or different aryl or cyclohexyl groups having a carbon
number of 6 or 7.) (g) sulfur-containing organic tin compound.
2. A constant-velocity joint for a propeller shaft in which a
grease containing the following components (a) to (g) as essential
components: (a) base oil (b) diurea type thickening agent expressed
by the following formula
R.sup.1NH--CO--NH--C.sub.6H.sub.4--p--CH.sub.2--C.sub.6H.sub.4--p-
--NH--CO--NHR.sup.2 (wherein R.sup.1 and R.sup.2 are the same or
different aryl or cyclohexyl groups having a carbon number of 6 or
7) (c) molybdenum sulfurized dialkyl dithiocarbamate, molybdenum
sulfurized dialkyl dithiophosphate, or a mixture thereof (d)
molybdenum disulfide (e) Zinc dithiophosphate compound,
sulfur-nitrogen-containing extreme-pressure agent, or an
extreme-pressure agent in which both are mixed (f) phosphorus-free,
sulfur-containing extreme-pressure agent (g) sulfur-containing
organic tin compound.
3. A constant-velocity joint for a propeller shaft as claimed in
claim 1 or 2 wherein the constant-velocity joint is a cross-groove
type constant-velocity joint.
4. A constant-velocity joint for a propeller shaft as claimed in
any of claim s 1-3 wherein the constant-velocity joint is a
constant-velocity joint in which the PCD clearance is negative and
a preload is imparted.
Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to a constant-velocity universal
joint for a propeller shaft used at a coupling portion of a
propeller shaft for transmitting a driving force in the
back-and-forth direction of an automobile body.
[0002] Such a constant-velocity joint for a propeller shaft, and a
constant-velocity joint for a drive shaft provided near a wheel and
used at a coupling portion of a drive shaft for transmitting the
rotation force from a differential gear to the wheel are typical
constant-velocity joints for automobiles.
[0003] Since a propeller shaft is a rather heavy object and rotates
at a high speed compared with a drive shaft, a load on the
constant-velocity joint is large and the accuracy of its motion
influences the degree of perfection of the propeller shaft.
[0004] A cross-groove type constant-velocity joint is known as a
constant-velocity joint used for such a propeller shaft. It has a
general structure as shown in FIGS. 1 and 2, in which a plurality
of grooves (also referred to as tracks) formed in the outer
peripheral surface of an inner ring 1 and the inner peripheral
surface of an outer ring 2 extend in such directions as to cross
each other (in a torsional relationship in a three-dimensional
view) with balls 5 mounted at portions where grooves 3 of the inner
ring 1 and opposing grooves 4 of the outer ring 2 cross each other.
The balls 5 are rotatably retained by a cage 6.
[0005] In such a constant-velocity joint, a lubricating grease is
sealed to prevent abnormal wear at portions that are liable to wear
due to the rotation of the shaft and to increase durability,
thereby maintaining the rotational resistance at a low level.
[0006] Various designs are proposed to cross-groove type
constant-velocity joints for propeller shafts. Ones are preferable
which are designed such that there will be no internal clearances,
particularly no clearance in the pitch circle (PCD) direction
(referred generally to as PCD clearance) so that they rotate
smoothly without producing vibration or abnormal sound especially
during high-speed rotation. In particular, ones structured such
that the PCD clearance is negative and a preload is applied are
used in applications where high-speed rotation is required.
[0007] Since such conventional constant-velocity joints for
propeller shafts are used in applications where they rotate at a
high speed exceeding 2000 rpm, the grease may be heated to high
temperature and deteriorate. If this happens, the frictional
surface may not be lubricated sufficiently.
[0008] Also, if a grease containing organic lead compound as an
extreme-pressure agent is sealed in a constant-velocity joint for a
propeller shaft, deterioration in quality of such a grease can be
avoided. But in view of a bad influence of the disposed grease on
the biosphere, using an organic lead compound as an additive should
be avoided if possible.
[0009] An object of this invention is to provide a
constant-velocity joint for a propeller shaft which can be used
with good durability without adding any organic lead compound,
which is high in the effect of suppressing temperature rise of
grease (so-called temperature-rise suppressing effect) especially
during high-speed rotation, and which can prevent quality
deterioration of the grease.
[0010] Another object of this invention is to provide a
cross-groove type constant-velocity joint for a propeller shaft in
which the PCD clearance is negative and a preload is imparted, and
which is high in the temperature-rise suppressing effect.
SUMMARY OF THE INVENTION
[0011] According to this invention, there is provided a
constant-velocity joint for a propeller shaft in which a grease
containing the following components (a), (b) and (g) as essential
components is sealed:
[0012] (a) base oil
[0013] (b) diurea type thickening agent expressed by the following
formula
R.sup.1NH--CO--NH--C.sub.6H.sub.4--p--CH.sub.2--C.sub.6H.sub.4--p--NH--CO--
-NHR.sup.2
[0014] (wherein R.sup.1 and R.sup.2 are the same or different aryl
or cyclohexyl groups having a carbon number of 6 or 7.)
[0015] (g) sulfur-containing organic tin compound.
[0016] As the constant-velocity joint for a propeller shaft, a
cross-groove type constant-velocity joint may be used. Furthermore,
if the constant-velocity joint for a propeller shaft is one in
which the PCD clearance is negative and a preload is applied, it is
preferable to employ the abovementioned grease to obtain a desired
effect.
[0017] The grease using diurea which is component (b) has a stable
micellar structure and adheres more strongly to metal surface,
compared with an aliphatic diurea grease using an aliphatic amine
and a lithium soap grease when used in a cross-groove type
constant-velocity joint, which is subjected to a strong shearing
force. Also, metal-to-metal contact is prevented by the thickening
agent.
[0018] In the present invention, since a lubricating grease
containing a diurea type thickening agent and a sulfur-containing
organic tin compound is sealed in a constant-velocity joint for a
propeller shaft, durability is improved without adding any organic
lead compound. Also, the effect of suppressing the temperature rise
of the grease especially during high-speed rotation, and of
preventing deterioration of quality of the grease can be
expected.
[0019] In another invention of the present application, there is
provided, in the above-described constant-velocity joint for a
propeller shaft, a constant-velocity joint for a propeller shaft in
which a grease containing the following components (a) to (g) as
essential components:
[0020] (a) base oil
[0021] (b) diurea type thickening agent expressed by the following
formula
R.sup.1NH--CO--NH--C.sub.6H.sub.4--p--CH.sub.2--C.sub.6H.sub.4--p--NH--CO--
-NHR.sup.2
[0022] (wherein R.sup.1 and R.sup.2 are the same or different aryl
or cyclohexyl groups having a carbon number of 6 or 7.)
[0023] (c) molybdenum sulfurized dialkyl dithiocarbamate,
molybdenum sulfurized dialkyl dithiophosphate, or a mixture
thereof
[0024] (d) molybdenum disulfide
[0025] (e) Zinc dithiophosphate compound,
sulfur-nitrogen-containing extreme-pressure agent or an
extreme-pressure agent in which both are mixed
[0026] (f) phosphorus-free, sulfur-containing extreme-pressure
agent
[0027] (g) sulfur-containing organic tin compound.
[0028] The constant-velocity joint for a propeller shaft in which a
grease containing the components (c), (d), (e) and (f) besides
component (g) as extreme-pressure agents is sealed is one in which
a grease not containing an organic lead compound is sealed.
Moreover, it provides a constant-velocity joint for a propeller
shaft that is higher in durability and the temperature-rise
suppressing effect than the grease not containing components (c),
(d), (e) and (f).
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 is a vertical sectional view of a cross-groove type
constant-velocity joint;
[0030] FIG. 2 is a plan view of the same;
[0031] FIG. 3 is an enlarged sectional view showing how the balls
are mounted in the grooves; and
[0032] FIG. 4 is a graph showing the relationship between the
preload and the peak temperature.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0033] The constant-velocity joint for a propeller shaft embodying
the present invention will be described with reference to the
accompanying drawings.
[0034] As shown in FIGS. 1-3, the constant-velocity joint for a
propeller shaft of the embodiment is a cross-groove type joint in
which balls 5 as the rolling elements are mounted in grooves formed
in the joint with a PCD clearance. A grease containing the
below-described components as essential components is sealed in the
joint.
[0035] As shown in FIGS. 1 and 2, in the cross-groove type
constant-velocity joint embodying the present invention, a
plurality of grooves are formed in the outer peripheral surface of
an inner ring 1 and the opposing inner peripheral surface of the
outer ring 2. The grooves 3 of the inner ring 1 and the grooves 4
of the outer ring 2 are formed in such directions as to cross each
other. The balls 5 are mounted so as to fit in the crossing
portions between the grooves 3 of the inner ring 1 and the grooves
4 of the outer ring 2. The balls 5 are rotatably retained by a
retainer 6.
[0036] As shown in FIG. 3, when a torque T is applied to the inner
ring 1, vertical load P act between the grooves 3 and 4 through the
balls 5. Also, axial loads act on pocket surfaces 7a and 7b of the
retainer 6. They act as slide resistance and bending resistance of
the joint.
[0037] Such a cross-groove type constant-velocity joint is so
designed that there will be no internal clearance. In particular,
ones having such a structure in which the clearance in the pitch
circle direction (PCD) is negative (that is, resiliently compressed
state) and the balls are pressed into the grooves 3, 4 with a
preload applied are often used. In other words, in such a
cross-groove type constant-velocity joint, the balls are pressed
against the groove walls of the joint and resiliently compressed
particularly in the pitch circle direction (PCD).
[0038] The grease sealed in such a cross-groove type
constant-velocity joint has such a composition that the components
(a), (b) and (g) are contained as essential components or that the
components (a) to (f) and (g) are contained as essential
components.
[0039] As the base oil of component (a) used in this invention, a
mineral oil, ester type synthetic oil, ether type synthetic oil, or
a hydrocarbon type synthetic oil can be used. Any other known
lubricating oil may also be employed. They may be used singly or in
combination.
[0040] The diurea type thickening agent as component (b) used in
this invention comprises a diurea compound expressed by the
following formula:
R.sup.1NH--CO--NH--C.sub.6H.sub.4--p--CH.sub.2--C.sub.6H.sub.4--p--NH--CO--
-NHR.sup.2
[0041] (wherein R.sup.1 and R.sup.2 are the same or different aryl
or cyclohexyl groups having a carbon number of 6 or 7.)
[0042] Such a diurea type thickening agent is obtained by reacting
a monoamine such as aniline, p-toluidine and cyclohexylamine with
diphenylmethane-4,4'-diisocyanate. In practice, a micellar
structure is obtained by reacting raw materials in a base oil.
[0043] Among components (c) used in this invention, as molybdenum
sulfurized dialkyl dithiocarbamate (sometimes abbreviated as
MODTC), one expressed by the following formula is particularly
preferable.
[R.sup.3R.sup.4N--CS--S].sub.2--Mo.sub.2OmSn
[0044] (wherein R.sup.3 and R.sup.4 are alkyl groups having a
carbon number of 1 to 24. m+n=4, m=0 to 3, n=4 to 1.)
[0045] The above compound is a well known solid lubricant and is
disclosed in Japanese patent publication 45-24562 (in which m=2.35
to 3, n=1.65 to 1), patent publication 51-964 (in which m=0, n=4),
and patent publication 53-31646 (in which m=0.5 to 2.3, n=3.5 to
1.7).
[0046] Among components (c) used in this invention, molybdenum
sulfurized dialkyl dithiophosphate is an extreme-pressure agent
that is also called molybdenum dialkyldithiophosphate or MODTP and
expressed by the following chemical formula 1. 1
[0047] (wherein R.sup.5, R.sup.6, R.sup.7 and R.sup.8 are primary
or secondary alkyl groups having a carbon number of 1 to 24,
preferably 3 to 20 or aryl groups having a carbon number of 6 to
30, preferably 8 to 18.)
[0048] Molybdenum disulfide which is component (d) used in this
invention is a well known solid lubricant. Since molybdenum
disulfide has a laminar lattice structure and prevents metallic
contact by being easily sheared into thin layers by slide movement,
it has a seizure-preventive effect. But if the amount of addition
is too much, it may increase the friction coefficient and have a
bad influence on its vibration resistance, and also can increase
wear, though depending on the lubricating conditions.
[0049] As a preferable example of the Zinc dithiophosphate compound
(abbreviated as ZnDTP) of component (e) used in this invention, one
expressed by the following formula can be cited.
[(R.sup.9O).sub.2--PS--S].sub.2--Zn
[0050] (wherein R.sup.9 is an alkyl group having a carbon number of
1 to 24 or an aryl group having a carbon number of 6 to 30.
Especially preferably, R.sup.9 is a primary or secondary alkyl
group having a carbon number of 3 to 8.)
[0051] Such a Zinc dithiophosphate compound produces an olefin from
its alkyl groups by heat decomposition after adsorbed to a metal
(iron) surface, and produces hydrogen sulfide, mercaptan or alkyl
sulfide, and then forms an extreme-pressure film comprising an
inorganic polymer containing sulfur, phosphorus and zinc to perform
a wear preventive function.
[0052] The sulfur-nitrogen-containing extreme-pressure agent of
component (e) used in this invention is a known extreme-pressure
agent in which the sulfur content is 5-20 wt % and the nitrogen
content is 1-10 wt %. Among known extreme-pressure agents
containing no phosphorus and containing sulfur and nitrogen, it is
an extreme-pressure agent except molybdenum sulfurized dialkyl
dithiocarbamate. For example, Vanlube 601 made by R. T. Vanderbilt
company may be used.
[0053] The sulfur-base extreme-pressure agent not containing
phosphorus which is component (f) used in this invention is e.g. an
olefin sulfide such as isobutene sulfide or a sulfide-containing
compound such as dibenzyl disulfide, and is a well known
extreme-pressure agent in which the content of the sulfur component
is about 35-50 wt %.
[0054] As the sulfur-containing organic tin compound of component
(g) used in this invention, a compound expressed by the following
formula is a typical one.
(R.sup.10).sub.mSn(X).sub.4-m
[0055] (wherein R.sup.10 is an alkyl group, X represents
--S--(CH.sub.2)--CO--OR.sup.11 or
--S--(CH.sub.2).sub.n--O--CO--OR.sup.11- , R.sup.11 is an alkyl or
alkenyl group, n is an integer of 1 to 18, m is an integer of 0 to
3, n and m may be the same or different from each other if R.sup.10
and X are two or more.)
[0056] As specific examples of sulfur-containing organic tin
compound, dimethyl tin bis(isooctyl thioglycol), monomethyl tin
tris(isooctyl thioglycol) and di(n-octyl)tin bis(isooctyl
mercaptoacetate) can be cited.
[0057] The grease comprising such components as described above is
preferably of the following composition:
[0058] (a) base oil
[0059] (b) diurea type thickening agent: 1-25 wt %
[0060] (c) molybdenum sulfurized dialkyl dithiocarbamate,
molybdenum sulfurized dialkyl dithiophosphate, or a mixture
thereof: 0.1-5 wt %
[0061] (d) molybdenum disulfide: 0.1-5 wt %
[0062] (e) Zinc dithiophosphate compound, sulfur-nitrogen-base
extreme-pressure agent or an extreme-pressure agent in which both
of them are mixed: 0.05-3 wt %
[0063] (f) phosphorus-free, sulfur-containing extreme-pressure
agent: 0.1-5 wt %
[0064] (g) sulfur-containing organic tin compound: 0.1-5 wt %
[0065] As a more preferable composition of the grease, the
following one can be cited.
[0066] (a) base oil
[0067] (b) diurea type thickening agent: 1-25 wt %
[0068] (c) molybdenum sulfurized dialkyl dithiocarbamate,
molybdenum sulfurized dialkyl dithiophosphate, or a mixture
thereof: 1-3 wt %
[0069] (d) molybdenum disulfide: 0.1-3 wt %, more preferably 0.1-2
wt %
[0070] (e) Zinc dithiophosphate compound, sulfur-nitrogen-base
extreme-pressure agent or an extreme-pressure agent in which both
of them are mixed: 1-2 wt %
[0071] (f) phosphorus-free, sulfur-containing extreme-pressure
agent: 1-3 wt %
[0072] (g) sulfur-containing organic tin compound: 1-3 wt %
EXAMPLES AND CMPARATIVE EXAMPLES
Example 1
[0073] (Example of a Lubricating Grease Not Containing Organic Lead
but Containing Organic Tin)
[0074] 4100 g of base oil and 1012 g of
diphenylmethane-4,4'-diisocyanate were put in a container and the
mixture was heated to 70-80.degree. C. 4100 g of base oil, 563 g of
cyclohexylamine and 225 g of aniline were put in another container.
After heating them to 70-80.degree. C., the mixture was added to
the former container. The mixture was reacted for 30 minutes while
sufficiently agitating. Thereafter, its temperature was raised to
160 .degree. C. while agitating, and it was let to cool to obtain a
base urea grease.
[0075] To this base grease, the following components (c)-(g) were
added and mixed, and a lubricating grease of No. 1 grade
consistency was prepared by use of a three-stage roll mill.
[0076] (c) molybdenum sulfurized dialkyl dithiocarbamate (vanlube
601 made by R. T. Vanderbilt company): 3 wt %
[0077] (d) molybdenum disulfide: 1 wt %
[0078] (e) Zinc dithiophosphate compound (Lubrizol 1360 made by
Japan Lubrizol): 2 wt %
[0079] (f) phosphorus-free, sulfur-containing extreme-pressure
agent (Anglamol 33 made by Japan Lubrizol): 2 wt %
[0080] (g) sulfur-containing organic tin compound (75/25 (weight
ratio) mixture of dimethyl tin bis(isooctyl thioglycol) and
monomethyl tin tris(isooctyl thioglycol): 1 wt %
[0081] In any of the above examples, as the base oil of the grease,
a mineral oil having the following properties was used.
[0082] Viscosity:
[0083] 141 mm.sup.2/s at 40.degree. C.
[0084] 13.5 mm.sup.2/s at 100.degree. C.
[0085] Viscosity index: 89
[0086] The lubricating grease obtained was sealed in a cross-groove
type constant-velocity joint for a propeller shaft of the same type
as the one shown in FIGS. 1-3 (in which the PCD clearance was
negative and a predetermined preload was applied), and a high-speed
endurance test (operating angle: 2 degrees, number of revolutions:
6000 rpm, torque: 200 Nm) was conducted.
[0087] The results thereof are shown in FIG. 4 as a relation
between the peak temperature (.degree.C.) and the preload amount
(N).
Comparative Example 1
[0088] (Example of a Lubricating Grease Not Containing Organic Lead
and Not Containing Organic Tin Either)
[0089] In exactly the same manner as in Example 1, a base urea
grease was prepared and a grease was prepared by adding the
following components (c) and (d) and mixing them.
[0090] (c) molybdenum sulfurized dialkyl dithiocarbamate (Vanlube
601 made by R. T. Vanderbilt company): 3 wt %
[0091] (d) molybdenum disulfide: 1 wt %
[0092] For the grease obtained, a high-speed endurance test on a
cross-groove type constant-velocity joint was conducted in exactly
the same manner as in Example 1. The results are shown in FIG.
4.
Comparative Example 2
[0093] (Example of a Lubricating Grease Not Containing Organic Lead
and Not Containing Organic Tin Either)
[0094] In exactly the same manner as in Example 1, a base urea
grease was prepared and a grease was manufactured by adding the
following components (c), (d) and (f) and mixing them.
[0095] (c) molybdenum sulfurized dialkyl dithiocarbamate (Vanlube
601 made by R. T. Vanderbilt company): 2 wt %, and molybdenum
sulfurized dialkyl dithiophosphate (MoDTP): 2 wt %
[0096] (d) molybdenum disulfide: 1 wt %
[0097] (f) phosphorus-free, sulfur-containing extreme-pressure
agent (Anglmol 33 made by Japan Lubrizol): 2 wt %
[0098] For the grease obtained, a high-speed endurance test on a
cross-groove type constant-velocity joint was conducted in exactly
the same manner as in Example 1. The results are shown in FIG.
4.
Comparative Example 3
[0099] (Example of a Grease Containing an Organic Lead but Not
Containing an Organic Tin)
[0100] In exactly the same manner as in Example 1, a base urea
grease was prepared and a grease was manufactured by adding the
following components (c), (e) and (h) and mixing them.
[0101] (c) molybdenum sulfurized dialkyl dithiocarbamate (Vanlube
601 made by R. T. Vanderbilt company): 3 wt %
[0102] (e) zinc dithiophosphate compound (Lubrizol 1360 made by
Japan Lubrizol) 2 wt %
[0103] (h) organic lead: 2 wt %
[0104] For the grease obtained, a high-speed endurance test on a
cross-groove type constant-velocity joint was conducted in exactly
the same manner as in Example 1. The results are also shown in FIG.
4.
[0105] As will be apparent from FIG. 4, for Comparative Examples 1
and 2 in which a lubricating grease not containing organic lead and
not containing organic tin either, the effect of suppressing
temperature rise of the grease during high-speed rotation was
insufficient, the properties of preventing deterioration of the
grease were not so good, and as a cross-groove type
constant-velocity joint, the performance was inferior.
[0106] Also, for Comparative Example 3 in which is used a grease
containing an organic lead but not containing organic tin, although
the temperature-rise suppressing effect of grease was recognized
during high-speed rotation, since it contained an organic lead, it
could not reliably avoid a bad influence of the grease on the
biosphere.
[0107] In contrast, for the cross-groove type constant-velocity
joint of Example 1 in which a grease of the predetermined
composition is sealed, in spite of the fact that a grease not
containing an organic lead is used in view of bad effect on the
environment, the effect of suppressing temperature rise of the
grease during high-speed rotation was sufficient and the properties
of preventing deterioration of the quality of the grease were
satisfactory. As a cross-groove type constant-velocity joint for a
propeller shaft, the performance was excellent.
[0108] As constant-velocity joints used for propeller shafts,
besides cross-groove type constant-velocity joints (LJ), double
offset type constant-velocity joints (DOJ) and Barfield type
constant-velocity joints (BJ) are sometimes used.
[0109] For each of these constant-velocity joints, the same greases
used in Example 1 and Comparative Examples 1-3 were sealed and a
high-load endurance test (operating angle: 2 degrees, number of
revolutions: 1000 rpm, torque: 800 Nm) was conducted. The results
are shown in Table 1.
[0110] These results were evaluated in three stages as excellent
(.circleincircle.), good (.smallcircle.) and inferior
(.times.).
[0111] As will be apparent from the results of Table 1, the
durability of the grease used in Example 1 and each
constant-velocity joint were even better than the case in which a
grease containing organic lead was used.
[0112] The constant-velocity joint for a propeller shaft in which a
grease containing components (a), (b) and (g) is sealed, even
though no environmentally harmful organic lead compound is
contained, can be used with good durability. The temperature rise
of the grease is suppressed during high-speed rotation, and in a
cross-groove type constant-velocity joint in which the PCD
clearance is negative and a preload is applied, deterioration of
the quality of the grease is prevented.
[0113] The constant-velocity joint for a propeller shaft in which a
grease containing components (a) to (g) is sealed, is high in
durability without adding any organic lead compound. Since the
temperature rise of the grease is suppressed especially during
high-speed rotation and deterioration of the quality of the grease
is prevented, it is excellent as a cross-groove type
constant-velocity joint in which the PCD clearance is negative and
a preload is imparted, especially as a constant-velocity joint for
a propeller shaft.
1 TABLE 1 Grease of Grease of Grease of Grease of comparative
comparative comparative example 1 example 1 example 2 example 3
Joint tested BJ .circleincircle. .largecircle. .largecircle.
.largecircle. DOJ .circleincircle. .largecircle. .largecircle.
.largecircle. LJ .largecircle. .largecircle. .DELTA.
.largecircle.
* * * * *