U.S. patent application number 14/758045 was filed with the patent office on 2015-12-10 for spherical annular seal member.
The applicant listed for this patent is (OILES CORPORATION). Invention is credited to Hiroaki WADA.
Application Number | 20150354434 14/758045 |
Document ID | / |
Family ID | 51020370 |
Filed Date | 2015-12-10 |
United States Patent
Application |
20150354434 |
Kind Code |
A1 |
WADA; Hiroaki |
December 10, 2015 |
SPHERICAL ANNULAR SEAL MEMBER
Abstract
A spherical annular seal member 35 for use in an exhaust pipe
joint has a spherical annular base member 33 which is defined by a
cylindrical inner surface 29 forming a through hole 28, a partially
convex spherical sliding surface 39, and annular end faces 31 and
32 on large- and small-diameter sides of the partially convex
spherical sliding surface 39.
Inventors: |
WADA; Hiroaki;
(Fujisawa-shi, Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
(OILES CORPORATION) |
Tokyo |
|
JP |
|
|
Family ID: |
51020370 |
Appl. No.: |
14/758045 |
Filed: |
December 18, 2013 |
PCT Filed: |
December 18, 2013 |
PCT NO: |
PCT/JP2013/007435 |
371 Date: |
June 26, 2015 |
Current U.S.
Class: |
277/626 |
Current CPC
Class: |
F01N 13/1827 20130101;
F01N 2310/14 20130101; F16J 15/0812 20130101; F16J 15/126 20130101;
F01N 13/1811 20130101; F01N 13/16 20130101 |
International
Class: |
F01N 13/18 20060101
F01N013/18; F01N 13/16 20060101 F01N013/16 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 27, 2012 |
JP |
2012-285403 |
Claims
1. A spherical annular seal member for use in an exhaust pipe
joint, comprising: a spherical annular base member defined by a
cylindrical inner surface forming a through hole, a partially
convex spherical sliding surface, and annular end faces on large-
and small-diameter sides of said partially convex spherical sliding
surface, wherein said spherical annular base member includes a
heat-resistant material containing expanded graphite and compressed
and a reinforcing member made from a convoluted and compressed
metal wire net sheet, said heat-resistant material containing
expanded graphite fills meshes of the compressed metal wire net
sheet and is integrated with the metal wire net sheet in mixed
form, and the metal wire net sheet which extends along at least one
annular end face of said large- and small-diameter side annular end
faces and is exposed to an outside partially and discretely at said
one annular end face is constituted by a bent extended portion of
an innermost circumferential metal wire net sheet extending along
said cylindrical inner surface.
2. The spherical annular seal member according to claim 1, wherein
said bent extended portion extends to a proximal side of the
annular end on the large-diameter side of said partially convex
spherical sliding surface.
3. The spherical annular seal member according to claim 1, wherein
said bent extended portion extends to a proximal side of the
annular end on the small-diameter side of said partially convex
spherical sliding surface.
4. A spherical annular seal member for use in an exhaust pipe
joint, comprising: a spherical annular base member defined by a
cylindrical inner surface forming a through hole, a partially
convex spherical sliding surface, and annular end faces on large-
and small-diameter sides of said partially convex spherical sliding
surface, wherein said spherical annular base member includes a
heat-resistant material containing expanded graphite and compressed
and a reinforcing member made from a convoluted and compressed
metal wire net sheet, said heat-resistant material containing
expanded graphite fills meshes of the compressed metal wire net
sheet and is integrated with the metal wire net sheet in mixed
form, and the metal wire net sheet which extends along at least one
annular end face of said large- and small-diameter side annular end
faces and is exposed to an outside partially and discretely at said
one annular end face is constituted by a bent extended portion of
an outermost circumferential metal wire net sheet extending along
partially convex spherical sliding surface.
5. The spherical annular seal member according to claim 4, wherein
said bent extended portion extends to a proximal side of an axial
annular end of said cylindrical inner surface at said
large-diameter side annular end face.
6. The spherical annular seal member according to claim 4, wherein
said bent extended portion extends to a proximal side of another
axial annular end of said cylindrical inner surface at said
small-diameter side annular end face.
7. The spherical annular seal member according to claim 1, wherein
said large-diameter side annular end face is constituted by an
annular flat end face which is continuously connected at an annular
large-diameter edge thereof to a large-diameter side annular end of
said partially convex spherical sliding surface and which is
continuously connected at an annular small-diameter edge thereof to
one annular axial end of said cylindrical inner surface.
8. The spherical annular seal member according to claim 1, wherein
said large-diameter side annular end face includes an annular flat
end face portion which is continuously connected at its annular
large-diameter edge to the large-diameter side annular end of said
partially convex spherical sliding surface and an annular concave
end face portion which is continuously connected at a
large-diameter edge thereof to an annular small-diameter edge of
said annular flat end face portion and is continuously connected at
a small-diameter edge thereof to the one annular axial end of said
cylindrical inner surface.
9. The spherical annular seal member according to claim 1, wherein
said large-diameter side annular end face includes an annular flat
end face portion which is continuously connected at its annular
small-diameter edge to the one annular axial end of said
cylindrical inner surface and an annular concave end face portion
which is continuously connected at a small-diameter edge thereof to
an annular large-diameter edge of said annular flat end face
portion and is continuously connected at a large-diameter edge
thereof to the large-diameter side annular end of said partially
convex spherical sliding surface.
10. The spherical annular seal member according to claim 1, wherein
said large-diameter side annular end face includes an annular
concave end face portion which is continuously connected at its
annular large-diameter edge to the large-diameter side annular end
of said partially convex spherical sliding surface, an annular flat
end face portion which is continuously connected at a
large-diameter edge thereof to a small-diameter edge of said
concave end face portion, and an annular concave end face portion
which is continuously connected at a large-diameter edge thereof to
an annular small-diameter edge of said annular flat end face
portion and is continuously connected at a small-diameter edge
thereof to the one annular axial end of said cylindrical inner
surface.
11. The spherical annular seal member according to claim 1, wherein
said spherical annular base member includes a spherical annular
base member body and an outer layer formed on an outer peripheral
side of said spherical annular base member body, and, in said outer
layer, said heat-resistant material containing expanded graphite, a
solid lubricant consisting of a lubricating composition containing
at least hexagonal boron nitride and hydrated alumina, and said
reinforcing member made from the metal wire net sheet are
compressed such that said solid lubricant and said heat-resistant
material are filled in the meshes of said reinforcing member, and
such that said solid lubricant, said heat-resistant material, and
said reinforcing member are integrated in mixed form, an outer
surface of said outer layer forming said partially convex spherical
sliding surface, said partially convex spherical sliding surface
being formed into a smooth surface in which surface constituted by
said reinforcing member and surface constituted by said solid
lubricant are present in mixed form or into a smooth surface
constituted by said solid lubricant.
12. The spherical annular seal member according to claim 11,
wherein said lubricating composition contains a
polytetrafluoroethylene resin.
13. The spherical annular seal member according to claim 11,
wherein the hydrated alumina is selected from among alumina
monohydrate, alumina trihydrate, and pseudoboehmite.
Description
TECHNICAL FIELD
[0001] The present invention relates to a spherical annular seal
member which is used in a spherical pipe joint for an automobile
exhaust pipe.
BACKGROUND ART
[0002] Exhaust gases of an automobile engine are released to the
atmosphere through an exhaust pipe, and this exhaust pipe is
subjected to repeated stress owing to such as the roll behavior and
vibration of the engine, with the result that there is a
possibility of causing a fatigue failure of the exhaust pipe, and
there are also cases where the engine vibration causes the exhaust
pipe to resonate, thereby deteriorating the quietness of the
compartment interior. To overcome such problems, a means has been
adopted to absorb the stress by disposing a spherical pipe joint at
a predetermined portion of the exhaust pipe.
[0003] In Patent Document 1, for example, a spherical annular seal
member is proposed which has a cylindrical inner surface defining a
through hole in a central portion thereof, an outer surface formed
in the shape of a partially convex spherical surface, and annular
end faces on large- and small-diameter sides of the outer surface.
In its inner portion extending from the cylindrical inner surface
to the outer surface formed in the shape of the partially convex
spherical surface, the spherical annular seal member has a
reinforcing member made from a compressed metal wire net sheet, as
well as a heat-resistant material which contains expanded graphite,
fills meshes of the metal wire net sheet of this reinforcing
member, and is compressed in such a manner as to be formed
integrally with the metal wire net sheet of the reinforcing member
in mixed form.
PRIOR ART DOCUMENTS
Patent Document
[0004] Patent Document 1: JP-A-10-231934
SUMMARY OF THE INVENTION
Problems to be Solved by the Invention
[0005] Meanwhile, in the case where such a spherical annular seal
member is used as the exhaust pipe joint, in the assembly to the
exhaust pipe, the exhaust pipe is press fitted into the through
hole of the spherical annular seal member, and in the use after the
assembly the outer surface formed in the shape of the partially
convex spherical surface repeatedly undergoes sliding movement with
respect to the mating member, so that it is desired that the
cylindrical reinforcing member be bound to the heat-resistant
material compressed and containing expanded graphite to such an
extent that the cylindrical reinforcing member is not positionally
displaced at the time of press fitting and sliding contact. In
addition, in the assembly to the exhaust pipe, even in cases where
there arises a need to withdraw the exhaust pipe from the through
hole of the spherical annular seal member after the press fitting
of the exhaust pipe into the through hole of the spherical annular
seal member, it is also desired that the cylindrical reinforcing
member be bound to the heat-resistant material to such an extent
that the cylindrical reinforcing member is not positionally
displaced with respect to the heat-resistant material compressed
and containing expanded graphite.
[0006] The present invention has been devised on the basis of the
above-described aspects, and its object is to provide a spherical
annular seal member in which the reinforcing member made from the
metal wire net sheet is firmly bound to the heat-resistant material
compressed and containing expanded graphite.
Means for Overcoming the Problems
[0007] A spherical annular seal member in accordance with the
present invention for use in an exhaust pipe joint comprises: a
spherical annular base member defined by a cylindrical inner
surface forming a through hole, a partially convex spherical
sliding surface, and annular end faces on large- and small-diameter
sides of the partially convex spherical sliding surface, wherein
the spherical annular base member includes a heat-resistant
material containing expanded graphite and compressed and a
reinforcing member made from a convoluted and compressed metal wire
net sheet, the heat-resistant material containing expanded graphite
fills meshes of the compressed metal wire net sheet and is
integrated with the metal wire net sheet in mixed form, and the
metal wire net sheet which extends along at least one annular end
face of the large- and small-diameter side annular end faces and is
exposed to an outside partially and discretely at the one annular
end face is constituted by a bent extended portion of an innermost
circumferential metal wire net sheet extending along the
cylindrical inner surface.
[0008] According to the spherical annular seal member in accordance
with the present invention, since the metal wire net sheet which
extends along at least one annular end face of the large- and
small-diameter side annular end faces and is exposed to the outside
partially and discretely at the one annular end face is constituted
by a bent extended portion of an innermost circumferential metal
wire net sheet extending along the cylindrical inner surface, when
the exhaust pipe is press fitted into the through hole of the
spherical annular seal member and the exhaust pipe is withdrawn
from the through hole of the spherical annular seal member, that
bent extended portion acts as a hampering portion which resists the
frictional movement with respect to the heat-resistant material,
containing expanded graphite, of the innermost circumferential
metal wire net sheet extending along the cylindrical inner surface,
and is able to firmly bind the reinforcing member constituted by
the metal wire net sheet to the heat-resistant material compressed
and containing expanded graphite. Thus, it is possible to prevent
positional displacement between the innermost circumferential metal
wire net sheet and the heat-resistant material containing expanded
graphite around that innermost circumferential metal wire net
sheet.
[0009] In the spherical annular seal member in accordance with the
present invention, the bent extended portion may extend to a
proximal side of a large-diameter side annular end of the partially
convex spherical sliding surface, or in substitution therefor or in
conjunction therewith may extend to a proximal side of a
small-diameter side annular end of the partially convex spherical
sliding surface.
[0010] A spherical annular seal member in accordance with another
aspect of the present invention for use in an exhaust pipe joint
comprises: a spherical annular base member defined by a cylindrical
inner surface forming a through hole, a partially convex spherical
sliding surface, and annular end faces on large- and small-diameter
sides of the partially convex spherical sliding surface, wherein
the spherical annular base member includes a heat-resistant
material containing expanded graphite and compressed and a
reinforcing member made from a convoluted and compressed metal wire
net sheet, the heat-resistant material containing expanded graphite
fills meshes of the compressed metal wire net sheet and is
integrated with the metal wire net sheet in mixed form, and the
metal wire net sheet which extends along at least one annular end
face of the large- and small-diameter side annular end faces and is
exposed to an outside partially and discretely at the one annular
end face is constituted by a bent extended portion of an outermost
circumferential metal wire net sheet extending along partially
convex spherical sliding surface.
[0011] According to the spherical annular seal member in accordance
with the other aspect of the present invention, since the metal
wire net sheet which extends along at least one annular end face of
the large- and small-diameter side annular end faces and is exposed
to the outside partially and discretely at the one annular end face
is constituted by a bent extended portion of an outermost
circumferential metal wire net sheet extending along partially
convex spherical sliding surface, in the sliding of the partially
convex spherical sliding surface with respect to the mating member,
that bent extended portion acts as a hampering portion which
resists the frictional movement with respect to the heat-resistant
material, containing expanded graphite, of the outermost
circumferential metal wire net sheet extending along the partially
convex spherical sliding surface, and is able to firmly bind the
reinforcing member constituted by the metal wire net sheet to the
heat-resistant material compressed and containing expanded
graphite. Thus, it is possible to prevent positional displacement
between the outermost circumferential metal wire net sheet and the
heat-resistant material containing expanded graphite around that
outermost circumferential metal wire net sheet.
[0012] In the spherical annular seal member in accordance with the
other aspect of the present invention, the bent extended portion
may extend to a proximal side of an axial annular end of the
cylindrical inner surface at the large-diameter side annular end
face, or in substitution therefor or in conjunction therewith may
extend to a proximal side of another axial annular end of the
cylindrical inner surface at the small-diameter side annular end
face.
[0013] In each of the spherical annular seal members in accordance
with the present invention, the large-diameter side annular end
face may be constituted by an annular flat end face which is
continuously connected at an annular large-diameter edge thereof to
a large-diameter side annular end of the partially convex spherical
sliding surface and which is continuously connected at an annular
small-diameter edge thereof to one annular axial end of the
cylindrical inner surface, or in substitution therefor or in
conjunction therewith, may include an annular flat end face portion
which is continuously connected at an annular large-diameter edge
thereof to the large-diameter side annular end of the partially
convex spherical sliding surface and an annular concave end face
portion which is continuously connected at a large-diameter edge
thereof to an annular small-diameter edge of the annular flat end
face portion and is continuously connected at a small-diameter edge
thereof to the one annular axial end of the cylindrical inner
surface. Still alternately, in substitution therefor or in
conjunction therewith, the large-diameter side annular end face may
include an annular flat end face portion which is continuously
connected at an annular small-diameter edge thereof to the one
annular axial end of the cylindrical inner surface and an annular
concave end face portion which is continuously connected at a
small-diameter edge thereof to an annular large-diameter edge of
the annular flat end face portion and is continuously connected at
a large-diameter edge thereof to the large-diameter side annular
end of the partially convex spherical sliding surface. Still
further, in substitution therefor or in conjunction therewith, the
large-diameter side annular end face may include an annular concave
end face portion which is continuously connected at an annular
large-diameter edge thereof to the large-diameter side annular end
of the partially convex spherical sliding surface, an annular flat
end face portion which is continuously connected at a
large-diameter edge thereof to a small-diameter edge of the concave
end face portion, and an annular concave end face portion which is
continuously connected at a large-diameter edge thereof to an
annular small-diameter edge of the annular flat end face portion
and is continuously connected at a small-diameter edge thereof to
the one annular axial end of the cylindrical inner surface.
[0014] In each of the spherical annular seal members in accordance
with the present invention, the spherical annular base member may
include a spherical annular base member body and an outer layer
formed on an outer peripheral side of the spherical annular base
member body, and, in the outer layer, the heat-resistant material
containing expanded graphite, a solid lubricant consisting of a
lubricating composition containing at least hexagonal boron nitride
and hydrated alumina, and the reinforcing member made from the
metal wire net sheet are compressed such that the solid lubricant
and the heat-resistant material are filled in the meshes of the
reinforcing member, and such that the solid lubricant, the
heat-resistant material, and the reinforcing member are integrated
in mixed form, an outer surface of the outer layer forming the
partially convex spherical sliding surface, the partially convex
spherical sliding surface being formed into a smooth surface in
which surface constituted by the reinforcing member and surface
constituted by the solid lubricant are present in mixed form or
into a smooth surface constituted by the solid lubricant.
[0015] According to such a spherical annular seal member, it is
possible to avoid the dropping off of the solid lubricant from the
outer surface of the spherical annular base member body, with the
result that since the sliding with the mating member takes place at
the partially convex spherical sliding surface which is a smooth
surface where the solid lubricant and the reinforcing member are
present in mixed form, it is possible to prevent the generation of
abnormal frictional noise as practically as possible.
[0016] In the solid lubricant, hexagonal boron nitride exhibits
excellent lubricity particularly in the high-temperature region. In
addition, hydrated alumina itself among the components exhibits no
lubricity, but exhibits an effect in the formation of a firm
coating layer by improving the adhesiveness of the solid lubricant
onto the heat-resistant material surface, and exhibits the role of
deriving the lubricity of the hexagonal boron nitride by promoting
sliding between layers of plate crystals of the hexagonal boron
nitride.
[0017] The lubricating composition may contain a
polytetrafluoroethylene resin. The polytetrafluoroethylene resin
itself has a low frictional property, and as it is contained in the
lubricating composition, the polytetrafluoroethylene resin improves
the low frictional property of the lubricating composition, imparts
the low frictional property to the solid lubricant constituted of a
lubricating composition, and is capable of avoiding as practically
as possible the generation of abnormal frictional noise in the
friction with the mating member without causing stick-slip
(adhesion-slippage). Further, the polytetrafluoroethylene resin
imparts to the lubricating composition the action of enhancing the
ductility of the lubricating composition during compression
forming, with the result that the formation of a thin coating layer
is made possible.
[0018] The hydrated alumina is a compound which is expressed by a
composition formula: Al.sub.2O.sub.3.nH.sub.2O (in the composition
formula, 0<n<3). In this composition formula, n is normally a
number exceeding 0 (zero) and less than 3, preferably 0.5 to 2,
more preferably 0.7 to 1.5 or thereabouts. As the hydrated alumina,
it is possible to cite, for example, alumina monohydrate (aluminum
hydroxide oxide) such as boehmite (Al.sub.2O.sub.3.nH.sub.2O) and
diaspore (Al.sub.2O.sub.3.H.sub.2O), alumina trihydrate such as
gibbsite (Al.sub.2O.sub.3.3H.sub.2O) and bayerite
(Al.sub.2O.sub.3.3H.sub.2O), pseudoboehmite, and the like, and at
least one of them is suitably used.
[0019] In the spherical annular seal member in accordance with the
present invention, the spherical annular base member body and the
outer layer may contain the reinforcing member constituted by the
metal wire net sheet at a ratio of 40 to 65% by weight and the
heat-resistant material containing expanded graphite and the solid
lubricant at a ratio of 35 to 60% by weight. The heat-resistant
material and the solid lubricant in the spherical annular base
member body and the outer layer may preferably have a density of
1.20 to 2.00 Mg/m.sup.3. In addition, the outer layer may
preferably contain the reinforcing member constituted by the metal
wire net sheet at a ratio of 60 to 75% by weight and the
heat-resistant material containing expanded graphite and the solid
lubricant at a ratio of 25 to 40% by weight.
[0020] If the spherical annular base member body and the outer
layer contain the reinforcing member by more than 65% by weight and
the heat-resistant material by less than 35% by weight, the sealing
(filling) of a multiplicity of infinitesimal passages (gaps)
occurring around the reinforcing member by the heat-resistant
material is not effected completely, with the result that leakage
of exhaust gases can occur at an early period, and even of the
sealing of the infinitesimal passages happened to be effected
completely, such sealing can be lost at an early period due to the
oxidative wear and the like of the heat-resistant material under
high temperatures, leading to the leakage of exhaust gases at an
early period. Meanwhile, if the reinforcing member is contained by
less than 40% by weight, and the heat-resistant material is
contained by more than 60% by weight, the amount of reinforcing
member contained becomes quite small in the outer layer and in the
vicinity of the outer layer, and the reinforcement of the
heat-resistant material in the outer layer and in the vicinity of
the outer layer fails to be effected satisfactorily, which can
result in the noticeable occurrence of exfoliation (dropping off)
of the heat-resistant material and makes it difficult to expect the
effect of reinforcement by the reinforcing member.
[0021] In addition, as for the heat-resistant material and the
solid lubricant in the spherical annular base member body and the
outer layer, if the heat-resistant material has a density of less
than 1.20 Mg/m.sup.3, the leakage of exhaust gases can result over
extended periods of use, whereas if the heat-resistant material has
a density of greater than 2.00 Mg/m.sup.3, abnormal frictional
noise is frequently liable to occur in the friction with the mating
member.
[0022] In the spherical annular seal member in accordance with the
present invention, since the outer layer has the partially convex
spherical sliding surface constituted by the outer surface which is
formed by an exposed surface where surface constituted by the
reinforcing member and surface constituted by the solid lubricant
are present in mixed form, it is possible to ensure smoother
sliding with the mating member which is in contact (slides) with
that partially convex spherical sliding surface. In addition, the
surface constituted by the solid lubricant in the that partially
convex spherical sliding surface can be held by the surface
constituted by the reinforcing member, and it is possible to
appropriately effect both the transfer of the solid lubricant from
that partially convex spherical sliding surface onto the surface of
the mating member and the scraping off of an excessive solid
lubricant transferred onto the surface of the mating member, with
the result that it is possible to ensure smooth sliding over
extended periods of time, and the generation of abnormal frictional
noise in sliding with the mating member can be eliminated.
[0023] In the spherical annular seal member in accordance with the
present invention, the heat-resistant material may contain at least
one of 0.05 to 5.0% by weight of phosphorus pentoxide and 1.0 to
16.0% by weight of a phosphate as an oxidation inhibitor, and
expanded graphite.
[0024] The heat-resistant material containing at least one of
phosphorus pentoxide and a phosphate as an oxidation inhibitor and
expanded graphite is able to improve the heat resistance and
oxidative wear characteristics of the spherical annular seal member
itself, and permits the use of the spherical annular seal member in
a high-temperature region.
Advantages of the Invention
[0025] According to the present invention, it is possible to
provide a spherical annular seal member in which the cylindrical
reinforcing member is firmly bound to the spherical annular base
member body.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Parts (a) and (b) of FIG. 1 are explanatory views of an
embodiment of the present invention;
[0027] FIG. 2 is a partially enlarged explanatory view of a
spherical annular seal member shown in FIG. 1;
[0028] FIG. 3 is a view explaining a method of forming a
reinforcing member in a process of manufacturing the spherical
annular seal member in accordance with the present invention;
[0029] FIG. 4 is a plan view illustrating meshes of a metal wire
net sheet of the reinforcing member;
[0030] FIG. 5 is a perspective view of a heat-resistant material in
the process of manufacturing the spherical annular seal member in
accordance with the present invention;
[0031] FIG. 6 is a perspective view of a superposed assembly in the
process of manufacturing the spherical annular seal member in
accordance with the present invention;
[0032] FIG. 7 is a plan view of a tubular base member in the
process of manufacturing the spherical annular seal member in
accordance with the present invention;
[0033] FIG. 8 is a vertical cross-sectional view of the tubular
base member shown in FIG. 7;
[0034] FIG. 9 is a perspective view of the heat-resistant material
in the process of manufacturing the spherical annular seal member
in accordance with the present invention;
[0035] FIG. 10 is a cross-sectional view of the heat-resistant
material having a coating layer of a solid lubricant in the process
of manufacturing the spherical annular seal member in accordance
with the present invention;
[0036] FIG. 11 is a view explaining a first method of forming an
outer-layer forming member in the process of manufacturing the
spherical annular seal member in accordance with the present
invention;
[0037] FIG. 12 is a view explaining the first method of forming the
outer-layer forming member in the process of manufacturing the
spherical annular seal member in accordance with the present
invention;
[0038] FIG. 13 is a vertical cross-sectional view of the
outer-layer forming member which is obtained by the first forming
method in the process of manufacturing the spherical annular seal
member in accordance with the present invention;
[0039] FIG. 14 is a view explaining a second method of forming the
outer-layer forming member in the process of manufacturing the
spherical annular seal member in accordance with the present
invention;
[0040] FIG. 15 is a view explaining the second method of forming
the outer-layer forming member in the process of manufacturing the
spherical annular seal member in accordance with the present
invention;
[0041] FIG. 16 is a plan view of a cylindrical preform in the
process of manufacturing the spherical annular seal member in
accordance with the present invention;
[0042] FIG. 17 is a cross-sectional view illustrating a state in
which the cylindrical preform is inserted in a die in the process
of manufacturing the spherical annular seal member in accordance
with the present invention;
[0043] FIG. 18 is a vertical cross-sectional view of an exhaust
pipe spherical joint incorporating the spherical annular seal
member in accordance with the present invention;
[0044] FIG. 19 is a plan view of another tubular base member in the
process of manufacturing the spherical annular seal member in
accordance with the present invention;
[0045] FIG. 20 is a plan view of still another tubular base member
in the process of manufacturing the spherical annular seal member
in accordance with the present invention;
[0046] FIG. 21 is a plan view of a further tubular base member in
the process of manufacturing the spherical annular seal member in
accordance with the present invention; and
[0047] Parts (a) and (b) of FIG. 22 are explanatory views of
another embodiment of the present invention.
MODE FOR CARRYING OUT THE INVENTION
[0048] Next, a more detailed description will be given of the
present invention on the basis of the preferred embodiments
illustrated in the drawings. It should be noted that the present
invention is not limited to these embodiments.
[0049] In FIGS. 1 and 2, a spherical annular seal member 35 which
is used in the exhaust pipe joint in accordance with this
embodiment has a spherical annular base member 33 which is defined
by a cylindrical inner surface 29 forming a through hole 28, a
partially convex spherical sliding surface 39, and annular end
faces 31 and 32 on large- and small-diameter sides of the partially
convex spherical sliding surface 39.
[0050] The spherical annular base member 33 includes a reinforcing
member 5 made from a convoluted and compressed metal wire net sheet
4 and a heat-resistant material 6 containing expanded graphite and
compressed in such a manner as to fill meshes of the compressed
metal wire net sheet 4 and to be integrated with the metal wire net
sheet 4 in mixed form, and this spherical annular base member 33
includes a spherical annular base member body 61 which is
cylindrically shaped and has a partially convex spherical surface
30 on an outer peripheral side thereof, as well as an outer layer
34 formed integrally on the partially convex spherical surface 30
of the spherical annular base member body 61.
[0051] To ensure that a clearance is not produced with respect to a
cylindrical outer surface 46 of a pipe end portion 101 of an
inserted upstream-side exhaust pipe 100 (see FIG. 18), the
cylindrical inner surface 29 having an axis O has a substantially
identical inside diameter to the outside diameter of the
cylindrical outer surface 46.
[0052] The annular end face 31 has an annular flat end face portion
53 which is continuously connected at an annular large-diameter
edge 51 to a large-diameter side annular end 52 of the partially
convex spherical sliding surface 39, as well as an annular concave
end face portion 58 which is continuously connected at a
large-diameter edge 55 to an annular small-diameter edge 54 of the
annular flat end face portion 53 and is continuously connected at a
small-diameter edge 56 to an annular end 57 in the axial direction
X of the cylindrical inner surface 29.
[0053] That portion of the metal wire net sheet 4 which extends
along the annular end face 31 and is exposed to the outside
partially and discretely at that annular end face 31 constitutes a
bent extended portion 62 of an innermost circumferential metal wire
net sheet 4 extending along the cylindrical inner surface 29, and
the bent extended portion 62 extends to a proximal side of the
annular end 52 of the partially convex spherical sliding surface
39.
[0054] Hereafter, a description will be given of constituent
materials of the spherical annular seal member 35 and a method of
manufacturing the spherical annular seal member 35.
<Concerning Heat-Resistant Sheet Material I for Heat-Resistant
Material>
[0055] While concentrated sulfuric acid of a 98% concentration is
being agitated, a 60% aqueous solution of hydrogen peroxide is
added to it as an oxidizing agent, and this solution is used as a
reaction solution. This reaction solution is cooled and kept at a
temperature of 10.degree. C., natural flake graphite powder having
a particle size of 30 to 80 meshes is added to it, and reaction is
allowed to take place for 30 minutes. After the reaction,
acid-treated graphite powder is separated by suction filtration,
and a cleaning operation is repeated twice in which the
acid-treated graphite powder is agitated in water for 10 minutes
and is then subjected to suction filtration, thereby sufficiently
removing the sulfuric acid content from the acid-treated graphite
powder. Then, the acid-treated graphite powder with the sulfuric
acid content sufficiently removed is dried for 3 hours in a drying
furnace held at a temperature of 110.degree. C., and this is used
as an acid-treated graphite powder.
[0056] This acid-treated graphite powder is subjected to heating
(expansion) treatment for 1 to 10 seconds at temperatures of 950 to
1200.degree. C. to produce cracked gas. The gaps between graphite
layers are expanded by its gas pressure to form expanded graphite
particles (expansion rate: 240 to 300 times). These expanded
graphite particles are fed to a twin roller apparatus adjusted to a
desired roll nip and is subjected to roll forming, thereby
fabricating an expanded graphite sheet having a desired thickness.
This expanded graphite sheet is used as a heat-resistant material
I.
<Concerning Heat-Resistant Materials II and III for
Heat-Resistant Material>
[0057] While the above-described acid-treated graphite powder is
being agitated, a solution in which at least one of an aqueous
solution of orthophosphoric acid of an 84% concentration as a
phosphoric acid and an aqueous solution aluminum primary phosphate
of a 50% concentration as a phosphate is diluted with methanol is
compounded with this acid-treated graphite powder by spraying, and
is agitated uniformly to fabricate a mixture having wettability.
This mixture having wettability is dried for two hours in a drying
furnace held at a temperature of 120.degree. C. Then, this mixture
is subjected to heating (expansion) treatment for 1 to 10 seconds
at temperatures of 950 to 1200.degree. C. to produce cracked gas.
The gaps between graphite layers are expanded by its gas pressure
to form expanded graphite particles (expansion rate: 240 to 300
times). In this expansion treatment process, the orthophosphoric
acid among the components undergoes dehydration reaction and
produces phosphorus pentaoxide, and water in the structural formula
of aluminum primary phosphate is eliminated. These expanded
graphite particles are fed to the twin roller apparatus adjusted to
a desired roll nip and is subjected to roll forming, thereby
fabricating an expanded graphite sheet having a desired thickness.
These expanded graphite sheets are used as heat-resistant materials
II and III.
[0058] Phosphorus pentaoxide or aluminum primary phosphate is
contained in the heat-resistant material II thus fabricated, and
phosphorus pentaoxide and aluminum primary phosphate are contained
in the heat-resistant material III. The expanded graphite
containing at least one of phosphorus pentaoxide and aluminum
primary phosphate permits use at, for instance, 500.degree. C. or a
high-temperature region exceeding 500.degree. C. since the heat
resistance of the expanded graphite itself is improved and the
oxidation inhibiting action is imparted thereto.
[0059] As the phosphate which can be used, it is possible to cite,
in addition to the orthophosphoric acid, metaphosphoric acid,
polyphosphoric acid, polymetaphosphate, and the like. In addition,
as the phosphate, it is possible to cite, in addition to the
aluminum primary phosphate, lithium primary phosphate, lithium
secondary phosphate, calcium primary phosphate, calcium secondary
phosphate, aluminum secondary phosphate, and the like.
[0060] In the manufacture of the spherical annular seal member 35,
as the heat-resistant sheet material, a sheet material having a
density of 1.0 to 1.15 Mg/m.sup.3 or thereabouts and a thickness of
0.3 to 0.6 mm or thereabouts is preferably used.
<Concerning Reinforcing Member>
[0061] As a reinforcing member, a metal wire net sheet is used
which is formed by weaving or knitting one or more fine metal wires
including, as an iron-based wire, a stainless steel wire made of
such as austenitic stainless steels SUS 304, SUS 310S, and SUS 316,
a ferritic stainless steel SUS 430, or an iron wire (JIS-G-3532) or
a galvanized steel wire (JIS-G-3547), or, as a copper wire, a wire
member made of a copper-nickel alloy (cupro-nickel) wire, a
copper-nickel-zinc alloy (nickel silver) wire, a brass wire, or a
beryllium copper wire.
[0062] As the fine metal wire for forming the metal wire net sheet,
a fine metal wire whose diameter is 0.28 to 3.2 mm or thereabouts
is used. In terms of the mesh size of the metal wire net sheet (see
FIG. 4 illustrating a woven metal wire net sheet) for a spherical
annular base member formed by the fine metal wire of that diameter,
a mesh size of 4 to 6 mm long and 3 to 5 mm wide or thereabouts is
suitably used, whereas, in terms of the mesh size (see FIG. 4) of
the metal wire net sheet for an outer layer, a mesh size of 2.5 to
3.5 mm long and 1.5 to 5 mm wide or thereabouts is suitably
used.
<Concerning Solid Lubricant>
[0063] A solid lubricant in this embodiment contains 70 to 85% by
weight of a hexagonal boron nitride (hereafter abbreviated as
`h-BN`), 0.1 to 10% by weight of boron oxide, and 5 to 20% by
weight of hydrated alumina, or contains a polytetrafluoroethylene
resin (hereafter referred to as PTFE) powder at a ratio of not more
than 200 parts by weight, preferably 50 to 150 parts by weight,
with respect to 100 parts by weight of this lubricating
composition.
[0064] This solid lubricant may contain boron oxide which derives
the lubricity inherent in h-BN by being contained in that h-BN and
contributes to the lowering of friction particularly in a
high-temperature region; however, the solid lubricant may not
contain the boron oxide. Even in such cases, the hydrated alumina
among the components of the solid lubricant exhibits an effect in
the formation of a firm coating layer by improving the adhesiveness
of the solid lubricant onto the heat-resistant material surface,
and exhibits the role of deriving the lubricity of h-BN by
promoting sliding between layers of plate crystals of h-BN.
[0065] In the manufacturing process, this solid lubricant is used
in the form of an aqueous dispersion in which an h-BN powder and a
boron oxide powder are dispersedly contained in an alumina sol in
which hydrated alumina particles are dispersedly contained in water
serving as a dispersion medium and containing an acid and whose
hydrogen ion concentration (pH) exhibits 2 to 3, the aqueous
dispersion dispersedly containing as a solid content 30 to 50% by
weight of a lubricating composition containing 70 to 85% by weight
of the h-BN powder, 0.1 to 10% by weight of boron oxide, and 5 to
20% by weight of hydrated alumina. Further, this aqueous dispersion
may be one in which 30 to 50% by weight of a lubricating
composition is dispersedly contained as a solid content, the
lubricating composition containing 70 to 85% by weight of the h-BN,
0.1 to 10% by weight of boron oxide, and 5 to 20% by weight of
hydrated alumina, as well as PTFE dispersedly contained at a ratio
of not more than 200 parts by weight, preferably 50 to 150 parts by
weight, with respect to 100 parts by weight of that lubricating
composition. The h-BN, the boron oxide, and PTFE for forming the
aqueous dispersion are preferably as fine powders as possible, and
fine powders with an average particle size of 10 .mu.m or less,
more preferably 0.5 .mu.m or less, are suitably used as these
powders.
[0066] The acid which is contained in water serving as a dispersion
medium for the alumina sol in the aqueous dispersion acts as a
deflocculant for stabilizing the alumina sol. As the acid, it is
possible to cite inorganic acids such as hydrochloric acid, nitric
acid, sulfuric acid, and amidesulfuric acid, but nitric acid, in
particular, is preferable.
[0067] The hydrated alumina for forming the alumina sol in the
aqueous dispersion is a compound which is expressed by a
composition formula: Al.sub.2O.sub.3.nH.sub.2O (in the composition
formula, 0<n<3). In this composition formula, n is normally a
number exceeding 0 (zero) and less than 3, preferably 0.5 to 2,
more preferably 0.7 to 1.5 or thereabouts. As the hydrated alumina,
it is possible to cite, for example, alumina monohydrate (aluminum
hydroxide oxide) such as boehmite (Al.sub.2O.sub.3.nH.sub.2O) and
diaspore (Al.sub.2O.sub.3.H.sub.2O), alumina trihydrate such as
gibbsite (Al.sub.2O.sub.3.3H.sub.2O) and bayerite
(Al.sub.2O.sub.3.3H.sub.2O), pseudoboehmite, and the like.
[0068] Next, referring to the drawings, a description will be given
of a method of manufacturing the spherical annular seal member 35
composed of the above-described constituent materials.
[0069] (First Process) As shown in FIG. 3, a hollow cylindrical
knitted metal wire net 1, which is formed by knitting a fine metal
wire with a diameter of 0.28 to 0.32 mm into a cylindrical shape
and whose mesh size is 4 to 6 mm long and 3 to 5 mm wide or
thereabouts (see FIG. 4), is passed between rollers 2 and 3 to
thereby fabricate a belt-shaped metal wire net sheet 4 having a
width D, and this metal wire net sheet 4 is cut into a
predetermined length L.
[0070] (Second Process) As shown in FIG. 5, a sheet-like
heat-resistant material (a heat-resistant material composed of
expanded graphite or expanded graphite including at least one of a
phosphoric acid and a phosphate) 6 is prepared which has a width
identical to or slightly smaller than the width D of the metal wire
net sheet 4, a length 1 of from 1.30.times.L mm to 2.70.times.L mm
with respect to the length L of the metal wire net sheet 4, a
density of from 1 to 1.5 Mg/m.sup.3, and a thickness of from 0.3 to
0.6 mm.
[0071] (Third Process) A superposed assembly 12 in which the
heat-resistant material 6 and the reinforcing member 5 are
superposed one on top of the other is obtained as follows: As shown
in FIG. 6, the reinforcing member 5 is made to project in the
widthwise direction from the heat-resistant material 6 such that
the length from one widthwise end 6a of the heat-resistant material
6 to one widthwise end 7 of the reinforcing member 5 becomes
.delta.1 (amount of projection .delta.1), the heat-resistant
material 6 is made to project in the widthwise direction from the
reinforcing member 5 such that the length from the other widthwise
end 8 of the reinforcing member 5 to the other widthwise end 6b of
the heat-resistant material 6 becomes .delta.2 (amount of
projection .delta.2), the heat-resistant material 6 is made to
project from one longitudinal end 9 of the reinforcing member 5 by
a maximum of from 0.3.times.L to 1.7.times.L, and the other
longitudinal end 10 of the reinforcing member 5 and a longitudinal
end 11 of the heat-resistant material 6 corresponding to that end
10 are made to agree with each other.
[0072] (Fourth Process) As shown in FIG. 7, the superposed assembly
12 is convoluted with the heat-resistant material 6 placed on the
inner side such that heat-resistant material 6 is convoluted with
one more turn, thereby forming a tubular base member 13 in which
the heat-resistant material 6 is exposed on both the inner
peripheral side and the outer peripheral side. As the
heat-resistant material 6, one is prepared in advance which has a
length 1 of from 1.30.times.L to 2.70.times.L with respect to the
length L of the reinforcing member 5 so that the number of winding
turns of the heat-resistant material 6 in the tubular base member
13 becomes greater than the number of winding turns of the
reinforcing member 5. In the tubular base member 13, as shown in
FIG. 8, the reinforcing member 5 on its one widthwise end 7 side
projects in the widthwise direction by .delta.1 from the one end 6a
of the heat-resistant material 6, while the heat-resistant material
6 on its other widthwise end 6b side projects in the widthwise
direction by .delta.2 from the other end 8 of the reinforcing
member 5.
[0073] (Fifth Process) Another heat-resistant material 6 such as
the one shown in FIG. 9 is separately prepared which is similar to
the above-described heat-resistant material 6 and has a width d and
has a length l+.alpha. of such a measure as to be able to be wound
around the tubular base member 13 by one turn.
[0074] (Sixth Process) The following aqueous dispersion is
prepared: an aqueous dispersion in which an h-BN powder and a boron
oxide powder are dispersedly contained in an alumina sol in which
hydrated alumina particles are dispersedly contained in water
serving as a dispersion medium and containing nitric acid acting as
a deflocculant and whose hydrogen ion concentration (pH) exhibits 2
to 3, the aqueous dispersion dispersedly containing as a solid
content 30 to 50% by weight of a lubricating composition containing
70 to 85% by weight of the h-BN, 0.1 to 10% by weight of boron
oxide, and 5 to 20% by weight of hydrated alumina; or an aqueous
dispersion in which 30 to 50% by weight of a lubricating
composition is dispersedly contained as a solid content, the
lubricating composition containing 70 to 85% by weight of the h-BN,
0.1 to 10% by weight of boron oxide, and 5 to 20% by weight of
hydrated alumina, as well as a PTFE powder contained at a ratio of
not more than 200 parts by weight, preferably 50 to 150 parts by
weight, with respect to 100 parts by weight of that lubricating
composition.
[0075] An aqueous dispersion (21 to 25.5% by weight of h-BN, 0.03
to 3% by weight of boron oxide, 1.5 to 6% by weight of hydrated
alumina, and 70% by weight of water), which dispersedly contains as
a solid content 30% by weight of a lubricating composition
containing 70 to 85% by weight of h-BN, 0.1 to 10% by weight of
boron oxide, and 5 to 20% by weight of hydrated alumina, is applied
to one surface of the heat-resistant material 6, shown in FIG. 9,
by means of brushing, roller coating, spraying, or the like, and
this is dried to thereby fabricate a coating layer 14 of the solid
lubricant constituted by that lubricating composition, as shown in
FIG. 10.
[0076] Alternatively, an aqueous dispersion (7 to 17% by weight of
h-BN, 0.009 to 2% by weight of boron oxide, 0.5 to 4% by weight of
hydrated alumina, 10 to 20% by weight of PTFE, and 70% by weight of
water), in which 30% by weight of a lubricating composition is
dispersedly contained as a solid content, the lubricating
composition containing 70 to 85% by weight of h-BN, 0.1 to 10% by
weight of boron oxide, and 5 to 20% by weight of hydrated alumina,
as well as a PTFE powder dispersedly contained at a ratio of not
more than 200 parts by weight, preferably 50 to 150 parts by
weight, with respect to 100 parts by weight of that lubricating
composition, i.e., the lubricating composition containing 23.3 to
56.7% by weight of h-BN, 0.03 to 6.7% by weight of boron oxide, 1.7
to 13.3% by weight of hydrated alumina, and 33.3 to 66.7% by weight
of PTFE, is applied to one surface of the heat-resistant material 6
shown in FIG. 9, by means of brushing, roller coating, spraying, or
the like, and this is dried to thereby fabricate the coating layer
14 of the solid lubricant constituted by that lubricating
composition such, as shown in FIG. 10.
[0077] (Seventh Process)
[0078] <First Method> As shown in FIGS. 11 to 13, the
heat-resistant material 6 having the coating layer 14 of the solid
lubricant is continuously inserted (see FIG. 11) into the hollow
cylindrical knitted metal wire net 1 obtained by continuously
knitting a fine metal wire with a wire diameter of 0.28 to 0.32 mm
by a knitting machine (not shown in the drawings). The hollow
cylindrical knitted metal wire net 1 with the heat-resistant
material 6 inserted therein is fed, starting with its insertion
start end side, into a nip .DELTA.1 between a pair of cylindrical
rollers 15 and 16 each having a smooth cylindrical outer peripheral
surface, so as to be integrated by being pressurized in the
thicknesswise direction of the heat-resistant material 6 (see FIG.
12), thereby filling the meshes of the metal wire net sheet 4 of
the reinforcing member 5 for the outer layer with the
heat-resistant material 6 and the coating layer 14 of the solid
lubricant formed on the surface of the heat-resistant material 6.
Thus, a flattened outer-layer forming member 19 is fabricated on
the surface of which surface 17 constituted by the reinforcing
member 5 for the outer layer and surface 18 constituted by the
solid lubricant are exposed in mixed form (see FIG. 13).
[0079] <Second Method> The reinforcing member 5 constituted
by the metal wire net sheet 4 described in the first process is
separately prepared, and, as shown in FIG. 14, the heat-resistant
material 6 having the coating layer 14 of the solid lubricant is
inserted into the reinforcing member 5 for the outer layer
constituted by the metal wire net sheet 4, and, as shown in FIG.
15, this assembly is fed into the nip .DELTA.1 between cylindrical
rollers 15 and 16 so as to be integrated by being pressurized in
the thicknesswise direction of the heat-resistant material 6,
thereby filling the meshes of the metal wire net sheet 4 of the
reinforcing member 5 for the outer layer with the heat-resistant
material 6 and the coating layer 14 of the solid lubricant formed
on the surface of that heat-resistant material 6. Thus, the
flattened outer-layer forming member 19 is fabricated on the
surface of which the surface 17 constituted by the reinforcing
member 5 for the outer layer and the surface 18 constituted by the
solid lubricant are exposed in mixed form.
[0080] <Third Method> A plain woven metal wire net sheet 4 is
prepared as a woven metal wire net sheet which is formed by weaving
a fine metal wire with a diameter of 0.28 to 0.32 mm. The
reinforcing member 5 for the outer layer made from this plain woven
metal wire net sheet 4 is cut to a predetermined length and width,
and two of these reinforcing members 5 are prepared. The
heat-resistant material 6 having the coating layer 14 of the solid
lubricant is inserted between the two reinforcing members 5 for the
outer layer, and this assembly is fed into the nip .DELTA.1 between
the pair of cylindrical rollers 15 and 16 so as to be integrated by
being pressurized in the thicknesswise direction of the
heat-resistant material 6, thereby filling the meshes of the metal
wire net sheet 4 of the reinforcing member 5 for the outer layer
with the heat-resistant material 6 and the coating layer 14 of the
solid lubricant formed on the surface of the heat-resistant
material 6. Thus, the flattened outer-layer forming member 19 is
fabricated on the surface of which the surface 17 constituted by
the reinforcing member 5 for the outer layer and the surface 18
constituted by the solid lubricant are exposed in mixed form.
[0081] In the above-described first, second, and third methods, 0.4
to 0.6 mm or thereabouts is suitable as the nip .DELTA.1 between
the pair of rollers.
[0082] (Eighth Process) The outer-layer forming member 19 thus
obtained is wound around an outer peripheral surface of the tubular
base member 13 with its coating layer 14 placed on the outer side,
thereby preparing a cylindrical preform 20 as shown in FIG. 16.
[0083] (Ninth Process) A die 27 such as the one shown in FIG. 17 is
prepared which has on its inner surface a cylindrical wall surface
21, a partially concave spherical wall surface 22 continuing from
the cylindrical wall surface 21, and a through hole 23 continuing
from the partially concave spherical wall surface 22, and in which
a hollow cylindrical portion 25 and a spherical annular hollow
portion 26 continuing from the hollow cylindrical portion 25 are
formed inside it as a stepped core 24 is fittingly inserted in the
through hole 23. Then, the cylindrical preform 20, in which the
portion of the metal wire net sheet 4 projecting in the axial
direction X with the amount of projection .delta.1 from the one
widthwise end 6a of the heat-resistant material 6 in the
reinforcing member 5 of the cylindrical preform 20 is bent radially
outwardly, as shown in FIG. 17, is fitted over the stepped core 24
of the die 27.
[0084] The cylindrical preform 20 disposed in the hollow
cylindrical portion 25 and the spherical annular hollow portion 26
of the die 27 is subjected to compression forming under a pressure
of 98 to 294 N/mm.sup.2 (1 to 3 tons/cm.sup.2) in the direction of
the core axis. Thus, the spherical annular seal member 35 is
fabricated which has the spherical annular base member 33 which is
defined by the cylindrical inner surface 29 forming the through
hole 28, the partially convex spherical sliding surface 39, and
annular end faces 31 and 32 on large- and small-diameter sides of
the partially convex spherical sliding surface 39, and which
includes the spherical annular base member body 61 and the outer
layer 34 formed integrally on the partially convex spherical
surface 30 of the spherical annular base member body 61, as shown
in FIGS. 1 and 2.
[0085] By means of this compression forming, the spherical annular
base member 33 is provided with the spherical annular base member
body 61 which is cylindrically shaped and has the partially convex
spherical surface 30 on its outer peripheral side, as well as the
outer layer 34 formed integrally on the partially convex spherical
surface 30 of the spherical annular base member body 61. Moreover,
the spherical annular base member 33 includes the reinforcing
member 5 made from the convoluted and compressed metal wire net
sheet 4 and the heat-resistant material 6 containing expanded
graphite and compressed in such a manner as to fill meshes of the
metal wire net sheet 4 and to be integrated with the metal wire net
sheet 4 in mixed form. The spherical annular base member body 61 is
constructed so as to be provided with structural integrity as the
heat-resistant material 6 and the metal wire net sheet 4 of the
reinforcing member 5 are compressed to each other and intertwined
with each other. In the outer layer 34, the heat-resistant material
6 containing expanded graphite, the solid lubricant constituted by
the lubricating composition containing h-BN and hydrated alumina or
additionally containing PTFE, and the reinforcing member 5 made
from the metal wire net sheet 4 are compressed such that the solid
lubricant and the heat-resistant material 6 are filled in the
meshes of the metal wire net sheet 4 of the reinforcing member 5,
and the solid lubricant, the heat-resistant material 6, and the
reinforcing member 5 are integrated in mixed form, an outer surface
36 of the outer layer 34 being thus formed into the partially
convex spherical sliding surface 39 serving as a smooth surface in
which surface 37 constituted by the reinforcing member 5 and
surface 38 constituted by the solid lubricant are present in mixed
form. That portion of the metal wire net sheet 4 which extends
along the annular end face 31 and is exposed to the outside
partially and discretely at that annular end face 31 constitutes
the bent extended portion 62 of the innermost circumferential metal
wire net sheet 4 extending along the cylindrical inner surface 29.
The bent extended portion 62, which is the portion of the innermost
circumferential metal wire net sheet 4 projecting in the axial
direction X with the amount of projection .delta.1 from the one
widthwise end 6a of the heat-resistant material 6 in the tubular
base member 13, and which corresponds to the bent portion at the
time when the cylindrical preform 20 is fitted over the stepped
core 24 of the die 27, extends to the proximal side of the annular
end 52 of the partially convex spherical sliding surface 39.
[0086] In the spherical annular base member body 61 and the outer
layer 34 of the fabricated spherical annular seal member 35, the
reinforcing member 5 constituted by the metal wire net sheet 4 is
contained at a ratio of 40 to 65% by weight, and the heat-resistant
material 6 containing expanded graphite and the solid lubricant are
contained at a ratio of 35 to 60% by weight. The heat-resistant
material 6 and the solid lubricant in the spherical annular base
member body 61 and the outer layer 34 have a density of 1.20 to
2.00 Mg/m.sup.3.
[0087] In addition, if attention is focused on the outer layer 34
alone, the reinforcing member 5 constituted by the metal wire net
sheet 4 is contained at a ratio of 60 to 75% by weight, and the
heat-resistant material 6 containing expanded graphite and the
solid lubricant are contained at a ratio of 25 to 40% by
weight.
[0088] In the exhaust pipe spherical joint, shown in FIG. 18, in
which the spherical annular seal member 35 is used by being
incorporated therein, a flange 200 is provided uprightly on an
outer peripheral surface of the upstream-side exhaust pipe 100,
which is connected to the engine side, by leaving a pipe end
portion 101. The spherical annular seal member 35 is press fitted
over the pipe end portion 101 at the cylindrical inner surface 29
defining the through hole 28, and is seated with its large-diameter
side annular end face 31 abutting against that flange 200. A flared
portion 301, which integrally has a concave spherical surface
portion 302 and a flange portion 303 continuous from the concave
spherical surface portion 302, is secured to a downstream-side
exhaust pipe 300 which is disposed in such a manner as to oppose
the upstream-side exhaust pipe 100 in the axial direction X and is
connected to the muffler side. An inner surface 304 of the concave
spherical surface portion 302 is in slidable contact with the
partially convex spherical sliding surface 39 in which the surface
37 constituted by the reinforcing member 5 and the surface 38
constituted by the solid lubricant are present in mixed form in the
outer surface 36 of the outer layer 34 of the spherical annular
seal member 35. The downstream-side exhaust pipe 300 is constantly
urged resiliently toward the upstream-side exhaust pipe 100 by
means of a pair of bolts 400 each having one end fixed to the
flange 200 and another end arranged by being inserted in the flange
portion 303 of the flared portion 301, and by means of a pair of
coil springs 500 each arranged between an enlarged head of the bolt
400 and the flange portion 303.
[0089] The exhaust pipe spherical joint shown in FIG. 18 is
arranged such that relative angular displacements occurring in the
upstream- and downstream-side exhaust pipes 100 and 300 are adapted
to be allowed by sliding contact between the smooth partially
convex spherical sliding surface 39 serving as a sliding surface of
the outer layer 34 of the spherical annular seal member 35 and the
inner surface 304 of the concave spherical surface portion 302 of
the flared portion 301 formed at the end of the downstream-side
exhaust pipe 300.
[0090] The spherical annular seal member 35 in accordance with this
embodiment has the spherical annular base member 33 which is
defined by the cylindrical inner surface 29 forming the through
hole 28, the partially convex spherical sliding surface 39, and the
annular end faces 31 and 32 on the large- and small-diameter sides
of the partially convex spherical sliding surface 39. Further, the
spherical annular base member 33 includes the reinforcing member 5
made from the convoluted and compressed metal wire net sheet 4 and
the heat-resistant material 6 containing expanded graphite and
compressed in such a manner as to fill meshes of the metal wire net
sheet 4 and to be integrated with the metal wire net sheet 4 in
mixed form. Furthermore, that portion of the metal wire net sheet 4
which extends along the annular end face 31 and is exposed to the
outside partially and discretely at that annular end face 31
constitutes the bent extended portion 62 of the innermost
circumferential metal wire net sheet 4 extending along the
cylindrical inner surface 29, and the bent extended portion 62
extends to the proximal side of the annular end 52 of the partially
convex spherical sliding surface 39. Therefore, when the pipe end
portion 101 of the upstream-side exhaust pipe 100 is press fitted
into the through hole 28 of the spherical annular seal member 35,
that bent extended portion 62 acts as a hampering portion which
resists the frictional movement with respect to the heat-resistant
material 6, containing expanded graphite, of the innermost
circumferential metal wire net sheet 4 extending along the
cylindrical inner surface 29, and is able to firmly bind the
reinforcing member 5 constituted by the metal wire net sheet 4 to
the heat-resistant material 6 compressed and containing expanded
graphite. Thus, it is possible to prevent positional displacement
between the innermost circumferential metal wire net sheet 4 and
the heat-resistant material 6 containing expanded graphite around
that innermost circumferential metal wire net sheet 4, thereby
making it possible to suitably incorporate the spherical annular
seal member 35 into the exhaust pipe spherical joint.
[0091] According to the spherical annular seal member 35, the
spherical annular seal member 35 has the outer layer 34 formed on
the outer peripheral side of the spherical annular base member body
61, and, in the outer layer 34, the heat-resistant material 6
containing expanded graphite, the solid lubricant consisting of a
lubricating composition containing at least h-BN and hydrated
alumina, and the reinforcing member 5 made from the metal wire net
sheet 4 are compressed such that the solid lubricant and the
heat-resistant material 6 are filled in the meshes of the
reinforcing member 5, and such that the solid lubricant, the
heat-resistant material 6, and the reinforcing member 5 are
integrated in mixed form. The outer surface 36 of the outer layer
34 forms the partially convex spherical sliding surface 39, and
this partially convex spherical sliding surface 39 is formed into a
smooth surface in which the surface 37 constituted by the
reinforcing member 5 and the surface 38 constituted by the solid
lubricant are present in mixed form. Accordingly, it is possible to
avoid the dropping off of the solid lubricant, with the result that
since the sliding with the mating member takes place at the
partially convex spherical sliding surface 39 which is a smooth
surface where the solid lubricant and the reinforcing member 5 are
present in mixed form, it is possible to prevent the generation of
abnormal frictional noise as practically as possible.
[0092] In the spherical annular seal member 35, the metal wire net
sheet 4 constituted by the bent extended portion 62 of the
innermost circumferential metal wire net sheet 4 extending along
the cylindrical inner surface 29 is made to extend along the
annular end face 31 and is mixed with the heat-resistant material 6
containing expanded graphite at that annular end face 31 so as to
be exposed to the outside partially and discretely together with
that heat-resistant material 6. In substitution therefor or in
conjunction therewith, the following arrangement may be adopted: As
shown in FIG. 19, for example, a tubular base member 13 is formed
which has the reinforcing member 5 projecting by .delta.1 in the
widthwise direction from the one widthwise end 6a of the
heat-resistant material 6 on the one widthwise end 7 side and
projecting by .delta.3 in the widthwise direction from the other
widthwise end 6b of the heat-resistant material 6 on the other
widthwise end 8 side as well. After those portions of the metal
wire net sheet 4 that project in the axial direction X with the
amounts of projection .delta.1 and .delta.3 from the one widthwise
end 6a and the other widthwise end 6b, respectively, of the
heat-resistant material 6 in the reinforcing member 5 are bent
radially outwardly, a cylindrical preform 20 formed from such a
tubular base member 13 shown in FIG. 19 is fitted over the stepped
core 24 of the die 27 and is subjected to compression forming in
the same way as described above, thereby forming the spherical
annular seal member 35, such that the metal wire net sheet 4
constituted by the bent extended portion on the end 8 side of the
innermost circumferential metal wire net sheet 4 extending along
the cylindrical inner surface 29 is made to extend to a proximal
side of a small-diameter side annular end 65 of the partially
convex spherical sliding surface 39 along the annular end face 32
and is mixed with the heat-resistant material 6 containing expanded
graphite at that annular end face 32 so as to be exposed to the
outside partially and discretely together with that heat-resistant
material 6. In the case of such an example, when the pipe end
portion 101 of the upstream-side exhaust pipe 100 is withdrawn from
the through hole 28 of the spherical annular seal member 35 during
readjustment, that bent extended portion acts as a hampering
portion which resists the frictional movement with respect to the
heat-resistant material 6, containing expanded graphite, of the
innermost circumferential metal wire net sheet 4 extending along
the cylindrical inner surface 29, and is able to firmly bind the
reinforcing member 5 constituted by the metal wire net sheet 4 to
the heat-resistant material 6 compressed and containing expanded
graphite. Thus, it is possible to prevent positional displacement
between the innermost circumferential metal wire net sheet 4 and
the heat-resistant material 6 containing expanded graphite around
that innermost circumferential metal wire net sheet 4, thereby
making it possible to suitably incorporate the spherical annular
seal member 35 into the exhaust pipe spherical joint during
readjustment.
[0093] In the above-described spherical annular seal member 35, the
metal wire net sheet 4 constituted by the bent extended portion 62
of the innermost circumferential metal wire net sheet 4 extending
along the cylindrical inner surface 29 is made to extend along at
least one of the annular end face 31 and the annular end face 32
and is mixed with the heat-resistant material 6 containing expanded
graphite at at least one of the annular end face 31 and the annular
end face 32 so as to be exposed to the outside partially and
discretely together with that heat-resistant material 6. In
substitution therefor or in conjunction therewith, the following
arrangement may be adopted: As shown in FIG. 20, for example, a
cylindrical preform 20 provided with the outer-layer forming member
19 having the reinforcing member 5 projecting by .delta.4 and
.delta.5 in the widthwise direction from the respective widthwise
ends of the heat-resistant material 6 at both widthwise ends is
formed. After those portions of the metal wire net sheet 4 that
project in the axial direction X with the amounts of projection
.delta.4 and .delta.5, respectively, in the reinforcing member 5
are bent radially inwardly so as to form bent extended portions,
this cylindrical preform 20 is fitted over the stepped core 24 of
the die 27 and is subjected to compression forming in the same way
as described above, thereby forming the spherical annular seal
member 35, such that the metal wire net sheet 4 constituted by the
bent extended portion of the outermost circumferential metal wire
net sheet 4 extending along the partially convex spherical sliding
surface 30 is made to extend to proximal sides of axial ends 57 and
59 of the cylindrical inner surface 29 at the large- and
small-diameter side annular end faces 31 and 32 along the large-
and small-diameter side annular end faces 31 and 32 and is mixed
with the heat-resistant material 6 containing expanded graphite at
the respective annular end faces 31 and 32 so as to be exposed to
the outside partially and discretely together with that
heat-resistant material 6. In the case of such an example, in the
sliding of the partially convex spherical sliding surface with
respect to the mating member, that bent extended portion acts as a
hampering portion which resists the frictional movement with
respect to the heat-resistant material 6, containing expanded
graphite, of the outermost circumferential metal wire net sheet 4
extending along the partially convex spherical sliding surface 30,
and is able to firmly bind the reinforcing member 5 constituted by
the metal wire net sheet 4 to the heat-resistant material 6
compressed and containing expanded graphite. Thus, it is possible
to prevent positional displacement between the outermost
circumferential metal wire net sheet 4 and the heat-resistant
material 6 containing expanded graphite around that outermost
circumferential metal wire net sheet 4, thereby making it possible
to suitably incorporate the spherical annular seal member 35 into
the exhaust pipe spherical joint.
[0094] In the case where the cylindrical preform 20 shown in FIG.
20 is used, each of both axial bent extended portions of the
outermost circumferential metal wire net sheet 4 extending along
the partially convex spherical sliding surface 30 extends along
each of the corresponding large- and small-diameter side annular
end faces 31 and 32, and is exposed to the outside partially and
discretely at each of these annular end faces 31 and 32. However,
it is also possible to use the cylindrical preform 20 provided with
the outer-layer forming member 19 having the reinforcing member 5
which projects by .delta.4 or .delta.5 in the widthwise direction
from only one end of the heat-resistant material 6. In this case,
the bent extended portion, corresponding to the amount of
projection .delta.4 or .delta.5, of the outermost circumferential
metal wire net sheet 4 extending along the partially convex
spherical sliding surface 30 extends along the corresponding one of
the large- and small-diameter side annular end faces 31 and 32, and
is exposed to the outside partially and discretely at that annular
end faces 31 or 32.
[0095] Further, although, in the above-described embodiment, the
reinforcing member 5 which projects in the widthwise direction from
the end of the heat-resistant material 6, it is alternately
possible to adopt an arrangement in which, by using the reinforcing
member 5 which does not project in the widthwise direction from the
end of the heat-resistant material 6 and has an identical width to
the widthwise length of the heat-resistant material 6, and by the
compression forming of the cylindrical preform 20 by means of the
die 27, the metal wire net sheet 4 which extends along at least one
annular end face of the large- and small-diameter side annular end
faces 31 and 32 and is exposed to the outside partially and
discretely at that one annular end face is formed into at least one
of the bent extended portion of the innermost circumferential metal
wire net sheet 4 extending along the cylindrical inner surface 29
and the bent extended portion of the outermost circumferential
metal wire net sheet 4 extending along the partially convex
spherical sliding surface 39.
[0096] Further, the spherical annular seal member 35 may include,
instead of the annular end face 31 having the annular flat end face
portion 53 and the annular concave end face portion 58, for
example, an annular flat end face which is continuously connected
at the annular large-diameter edge 51 to the large-diameter side
annular end 52 of the partially convex spherical sliding surface 39
and which is continuously connected at the annular small-diameter
edge 54 to the annular end 57 in the axial direction X of the
cylindrical inner surface 29. Furthermore, the spherical annular
seal member 35 may have, in substitution for or in addition to the
above-described arrangement, an annular concave end face portion 73
which is continuously connected at its small-diameter edge 71 to
the large-diameter edge 51 and is continuously connected at its
large-diameter edge 72 to the annular end 52 of the partially
convex spherical sliding surface 39, as shown in parts (a) and (b)
of FIG. 22. In such a case, the small-diameter edge 54 of the
annular flat end face portion 53 may be continuously connected to
the end 57 of the cylindrical inner surface 29 directly or via the
concave end face portion 58.
[0097] Still further, the spherical annular seal member 35 may
include the spherical annular base member body 61 which has the
reinforcing member 5 and at least one of the solid lubricant and
the heat-resistant material 6 containing expanded graphite, and in
which the metal wire net sheet 4 of the reinforcing member 5 is
exposed on the surface or in which the metal wire net sheet 4 is
embedded.
DESCRIPTION OF REFERENCE NUMERALS
[0098] 28: through hole [0099] 29: cylindrical inner surface [0100]
30: partially convex spherical surface [0101] 31, 32: annular end
face [0102] 33: spherical annular base member [0103] 34: outer
layer [0104] 35: spherical annular seal member [0105] 39: partially
convex spherical sliding surface [0106] 62: bent extended
portion
* * * * *