U.S. patent application number 11/911842 was filed with the patent office on 2009-05-21 for sliding part and method of manufacturing the same.
This patent application is currently assigned to MITSUBISHI MATERIALS PMG CORPORATION. Invention is credited to Tsuneo Maruyama, Teruo Shimizu.
Application Number | 20090129963 11/911842 |
Document ID | / |
Family ID | 37214544 |
Filed Date | 2009-05-21 |
United States Patent
Application |
20090129963 |
Kind Code |
A1 |
Shimizu; Teruo ; et
al. |
May 21, 2009 |
Sliding Part and Method of Manufacturing the Same
Abstract
There is provided a sliding part in which a surface coverage
ratio of copper in the sliding part increases. A bearing which is
the sliding part is formed by filling the raw powder into the
filling portion of the forming mold, compacting the raw powder to
form a powder compact 6, and sintering the powder compact 6. A
copper-based raw powder is composed of a copper-based flat raw
powder 2 having an average diameter smaller than that of an
iron-based raw powder 1 and an aspect ratio larger than that of the
iron-based raw powder 1, and a copper-based small-sized raw powder
3 having the average diameter is smaller than that of the
copper-based flat raw powder 2. The copper is allowed to segregate
at the surface of the sliding part. In the bearing in which the
copper-based flat powder 2 segregates at the surface, the surface
is covered with the copper-based small-sized raw powder 3 that has
emerged on the surface, as well as the copper-based flat raw powder
2, thereby it is possible to increase the surface coverage ratio of
copper.
Inventors: |
Shimizu; Teruo; (Tokyo,
JP) ; Maruyama; Tsuneo; (Niigata-shi, JP) |
Correspondence
Address: |
DARBY & DARBY P.C.
P.O. BOX 770, Church Street Station
New York
NY
10008-0770
US
|
Assignee: |
MITSUBISHI MATERIALS PMG
CORPORATION
NIGATA-KEN
JP
|
Family ID: |
37214544 |
Appl. No.: |
11/911842 |
Filed: |
November 14, 2005 |
PCT Filed: |
November 14, 2005 |
PCT NO: |
PCT/JP05/20802 |
371 Date: |
October 18, 2007 |
Current U.S.
Class: |
419/23 ;
75/246 |
Current CPC
Class: |
F16C 2204/60 20130101;
F16C 2220/20 20130101; B22F 5/106 20130101; F16C 33/12 20130101;
B22F 2998/10 20130101; B22F 2998/00 20130101; F16C 33/14 20130101;
B22F 2998/00 20130101; B22F 1/0055 20130101; B22F 2998/10 20130101;
B22F 3/02 20130101; B22F 3/10 20130101 |
Class at
Publication: |
419/23 ;
75/246 |
International
Class: |
B22F 3/12 20060101
B22F003/12 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 20, 2005 |
JP |
2005-123009 |
Claims
1. A sliding part formed by sintering a powder compact, which is
fabricated by filling an iron-based raw powder and a copper-based
raw powder into a filling portion of a forming mold and compacting
the raw powders, wherein the copper-based raw powder is comprised
of a copper-based flat raw powder having an average diameter
smaller than that of the iron-based raw powder and an aspect ratio
larger than that of the iron-based raw powder; and a copper-based
small-sized raw powder having an average diameter smaller than that
of the copper-based flat raw powder, and copper segregates on a
surface of the sliding part.
2. The sliding part according to claim 1, wherein a surface
coverage ratio of copper is 80% or more.
3. The sliding part according to claim 1, wherein the aspect ratio
of the copper-based flat raw powder is 10 or more.
4. The sliding part according to claim 2, wherein a ratio of the
copper-based raw powder is 20 to 40% by weight with respect to all
raw powders.
5. A sliding part formed by sintering a powder compact, which is
fabricated by filling an iron-based raw powder and a copper-based
raw powder into a filling portion of a forming mold and compacting
the raw powders, wherein the copper-based raw powder is comprised
of a copper-based flat raw powder having an average value of a
maximum projected area smaller than that of the maximum projected
area of the iron-based raw powder and an aspect ratio larger than
that of the iron-based raw powder; and a copper-based small-sized
raw powder having an average value of a maximum projected area
smaller than that of the maximum projected area of the copper-based
flat raw powder, and copper segregates on a surface of the sliding
part.
6. The sliding part according to claim 5, wherein a surface
coverage ratio of copper is 80% or more.
7. A method of manufacturing a sliding part comprising; filling an
iron-based raw powder and a copper-based raw material into a
filling portion of a forming mold, compacting the raw powders to
form a powder compact, and sintering the powder compact; wherein
the copper-based raw powder is comprised of a copper-based flat raw
powder having an average diameter smaller than that of the
iron-based raw powder and an aspect ratio larger than that of the
iron-based raw powder; and a copper-based small-sized raw powder
having an average diameter smaller than that of the copper-based
flat raw powder, and copper segregates on a surface of the sliding
part.
8. A method of manufacturing a sliding part comprising; filling an
iron-based raw powder and a copper-based raw material into a
filling portion of a forming mold, compacting the raw powders to
form a powder compact, and sintering the powder compact; wherein
the copper-based raw powder is comprised of a copper-based flat raw
powder having an average value of a maximum projected area smaller
than that of the maximum projected area of the iron-based raw
powder and an aspect ratio larger than that of the iron-based raw
powder; and a copper-based small-sized raw powder having an average
value of a maximum projected area smaller than that of the maximum
projected area of the copper-based flat raw powder, and copper
segregates on a surface of the sliding part.
9. The method according to claim 7, wherein the aspect ratio of the
copper-based flat raw powder is 10 or more.
10. The method according to claim 7, wherein a ratio of the
copper-based raw powder is 20 to 40% by weight with respect to all
raw powders.
Description
TECHNICAL FIELD
[0001] The present invention relates to a sliding part such as a
bearing or the like and a method of manufacturing the same.
BACKGROUND ART
[0002] As a sliding part having reduced frictional resistance and
improved durability and generating no noise, a sliding part is
known that is a flat powder formed by sintering a powder compact,
which is fabricated by filling an iron-based raw powder and a
copper-based raw powder in a filling portion of a forming mold and
applying vibration to the mold at the same time for compacting, and
having an aspect ratio of the copper-based raw powder larger than
that of the iron-based raw powder, on a surface of which copper
segregates (for example, refer to Japanese Unexamined Patent
Application, First Publication No. 2003-221606); or a sliding part
that is a flat powder formed by sintering a powder compact, which
is fabricated by filling the iron-based raw powder and the
copper-based raw powder into the filling portion of the forming
mold and applying vibration to the mold at the same time for
compacting, and having an average value of a maximum projected area
of the copper-based raw powder larger than that of the iron-based
raw powder, in which the copper-base raw powder contains flat
powder of copper or copper-alloy and on a surface of which copper
segregates (for example, refer to Japanese Unexamined Patent
Application, First Publication No. 2004-84038).
DISCLOSURE OF INVENTION
Problems to be Solved by the Invention
[0003] However, in the above related art, the mixture of the
iron-based raw powder and the copper-based flat raw powder composed
of flat powder having a larger aspect ratio than the iron-based raw
powder is filled into the filling portion of the forming mold, and
at the same time vibration is applied to the forming mold, such
that the copper-based flat raw powder segregates at the outer side
within the filling portion, overlaps each other in the thickness
direction, and at the same time segregates at a gathering surface
in a state in which the direction intersecting the thickness
direction is aligned with the longitudinal direction of the
surface. However, the iron-based raw powder emerges at a part of
the surface, as well as the segregated copper-based flat raw
powder, and a gap is formed between the copper-based flat raw
powders which emerges at the surface and are adjacent to each
other. As a result, the gap between the copper-based raw powder and
the iron-based raw powder, or the gap between the copper-based flat
raw powders is formed in the surface. Due to these gaps, the
surface coverage ratio of the copper in the sliding part cannot be
increased.
[0004] Accordingly, it is an advantage of the present invention to
increase the surface coverage ratio of the copper in the sliding
part formed by filling the iron-based raw powder and the
copper-based raw powder having an aspect ratio larger than that of
the iron-based raw powder into the filling portion of the forming
mold, compacting the raw powders to form a powder compact, and
sintering the powder compact, in which the copper segregates at the
surface of the sliding part.
Means for Solving the Problem
[0005] According to a first aspect of the invention, a sliding part
is formed by filling an iron-based raw powder and a copper-based
raw powder into a filling portion of a forming mold, compacting the
raw powders to form a powder compact, and sintering the powder
compact. The copper-based raw powder is composed of a copper-based
flat raw powder having an average diameter smaller than that of the
iron-based raw powder and an aspect ratio larger than that of the
iron-based raw powder; and a copper-based small-sized raw powder
having the average diameter smaller than that of the copper-based
flat raw powder; and in which copper is allowed to segregate on a
surface of the sliding part.
[0006] According to a second aspect of the invention, in the
sliding part according to the first aspect, the surface coverage
ratio of copper in the sliding part is 80% or more.
[0007] According to a third aspect of the invention, in the sliding
part according to the first or second aspect, the aspect ratio of
the copper-based flat raw powder is 10 or more.
[0008] According to a fourth aspect of the invention, in the
sliding part according to the second aspect, the ratio of the
copper-based raw powder is 20 to 40% by weight with respect to all
raw powders.
[0009] According to a fifth aspect of the invention, a sliding part
is formed by filling an iron-based raw powder and a copper-based
raw powder into a filling portion of a forming mold, compacting the
raw powders to form a powder compact, and sintering the powder
compact. The copper-based raw powder consists of a copper-based
flat raw powder having an average value of a maximum projected area
smaller than that of the maximum projected area of the iron-based
raw powder and an aspect ratio larger than that of the iron-based
raw powder; and a copper-based small-sized raw powder having the
average value of the maximum projected area smaller than that of
the maximum projected area of the copper-based flat raw powder; and
in which copper is allowed to segregate on a surface of the sliding
part.
[0010] According to a sixth aspect of the invention, in the sliding
part according to the fifth aspect, a surface coverage ratio of
copper in the sliding part is 80% or more.
[0011] According to a seventh aspect of the invention, a method of
manufacturing a sliding part, includes steps of filling an
iron-based raw powder and a copper-based raw powder into a filling
portion of a forming mold, compacting the raw powders to form a
powder compact, and sintering the powder compact, in which the
copper-based raw powder consists of a copper-based flat raw powder
having the average diameter smaller than that of the iron-based raw
powder and an aspect ratio larger than that of the iron-based raw
powder; and a copper-based small-sized raw powder having an average
diameter smaller than that of the copper-based flat raw powder; and
the copper-based flat raw powder in the filling portion is allowed
to segregate on a surface of the powder compact.
[0012] According to an eighth aspect of the present invention, a
method of manufacturing a sliding part, includes steps of filling
an iron-based raw powder and a copper-based raw powder into a
filling portion of a forming mold, compacting the raw powders to
form a powder compact, and sintering the powder compact, in which
the copper-based raw powder is composed of a copper-based flat raw
powder having an average value of the maximum projected area
smaller than that of the maximum projected area of the iron-based
raw powder and an aspect ratio larger than that of the iron-based
raw powder; and a copper-based small-sized raw powder having an
average value of the maximum projected area smaller than that of
the maximum projected area of the copper-based flat raw powder, in
which the copper-based flat raw powder in the filling portion is
allowed to segregate on a surface of the powder compact.
[0013] According to a ninth aspect of the invention, in the method
of manufacturing the sliding part according to the seventh or
eighth aspect, the aspect ratio of the copper-based flat raw powder
is 10 or more.
[0014] According to a tenth aspect of the invention, in the method
of manufacturing the sliding part according to any one of the
seventh to ninth aspects, a ratio of the copper-based raw powder is
20 to 40% by weight with respect to all raw powders.
EFFECTS OF THE INVENTION
[0015] According to the first and fifth aspects of the present
invention, when a bearing is composed of the sliding part, the
copper-based small-sized raw powder as well as the copper-based
flat raw powder emerges at the surface, such that a rotator slides
on the surface covered with the copper, and the coefficient of the
friction between the rotation axis and the surface side decreases,
thus a rotation is performed smoothly. At the same time,
predetermined strength and durability can be obtained due to the
iron. Furthermore, in the above structure, even though the surface
on which the rotator rotates is abraded, since the predetermined
ratio of copper is contained below the surface, the durability of
the sliding portion becomes excellent.
[0016] According to the second and sixth aspects of the present
invention, the coefficient of the friction of the sliding portion
can be suppressed at a significantly lower level.
[0017] According to the third and ninth aspects of the present
invention, since the aspect ratio is set to 10 or more, when
vibration is applied, the flat powder segregates easily at the
surface, and thus it is possible to obtain the sliding part having
a high copper concentration at the surface.
[0018] According to the fourth aspect of the present invention,
when the ratio of the copper-based flat raw powder is less than 20%
by weight, the ratio of copper at the surface decreases and the
frictional resistance increases. In addition, when the ratio of
copper-based flat raw powder exceeds 40% by weight, the ratio of
the copper-based raw powder in all of the raw powders becomes too
large, and it is not favorable in terms of the strength. Therefore,
if the ratio is set in the range of 20 to 40%, the frictional
resistance decreases and it is possible to obtain a sliding part
having a high strength.
[0019] According to the seventh and eighth aspects of the present
invention, it is possible to obtain a sliding part having a low
coefficient of friction and an improved durability.
[0020] According to the tenth aspect of the present invention, when
the ratio of the copper-based flat raw powder is less than 20% by
weight, the ratio of copper at the surface decreases and the
frictional resistance increases. In addition, when the ratio of the
copper-based flat raw powder exceeds 40% by weight, the ratio
thereof becomes too large and it is not favorable in terms of the
strength. Therefore, if the ratio is set in the range of 20% to 40%
by weight, the frictional resistance decreases and it is possible
to obtain a sliding part having a high strength.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a flowchart illustrating a manufacturing method
according to a first embodiment of the present invention.
[0022] FIG. 2 is a schematic front elevation view of an iron-based
raw powder according to the first embodiment of the present
invention.
[0023] FIG. 3(A) is a schematic side elevation view illustrating a
copper-based raw powder according to the first embodiment of the
present invention.
[0024] FIG. 3(B) is a schematic front elevation view illustrating a
copper-based raw powder according to the first embodiment of the
present invention.
[0025] FIG. 4 is a schematic front elevation view of a copper-based
small-sized raw powder according to the first embodiment of the
present invention.
[0026] FIG. 5 is a perspective view illustrating a bearing
according to the first embodiment of the present invention.
[0027] FIG. 6 is a sectional view illustrating a forming mold
according to the first embodiment of the present invention.
[0028] FIG. 7 is a schematic sectional view illustrating a powder
compact according to the first embodiment of the present invention,
in which a portion of the powder compact is enlarged.
BRIEF DESCRIPTION OF THE REFERENCE SYMBOLS
[0029] 1: iron-based raw powder
[0030] 2: copper-based flat raw powder
[0031] 3: copper-based small-sized raw powder
[0032] 5: bearing
[0033] 6: powder compact
[0034] 11: forming mold
[0035] 16: filling portion
[0036] 51: sliding surface (sliding part)
BEST MODE FOR CARRYING OUT THE INVENTION
[0037] Hereinafter, a preferred embodiment of the present invention
will be described with reference to the attached drawings. However,
the embodiment to be described below is not intended to limit the
invention described in claims. Furthermore, the entire
constitutions to be described later are not essential to the
invention.
Embodiment 1
[0038] A method of manufacturing the invention will now be
described. An iron-based raw powder 1, a copper-based flat raw
powder 2, and a copper-based small-sized raw powder 3 are mixed at
a predetermined ratio (S1). As shown in FIG. 2, as the iron-based
raw powder 1, an irregular-shaped powder having a substantially
spherical shape such as an atomized powder is used. An average
diameter of the iron-based raw powder 1 is in the range of 50 to
100 .mu.m, but is preferably in the range of 60 to 80 .mu.m.
Furthermore, as shown in FIG. 3, a flat powder is used as the
copper-based raw material 2. An aspect ratio (diameter D/thickness
T) of the flat powder is 10% or more, but is preferably in the
range of 20 to 50%. The average diameter D of the copper-based flat
raw powder 2 is 80 .mu.m, and the average thickness T is in the
range of 1 to 5 82 m. Furthermore, as the copper-based flat raw
powder 2, it is possible to use a mixture consisting of a copper
powder as the main component and a tin powder in the range of 2 to
30% by weight. Furthermore, as shown in FIG. 4, an irregular-shaped
powder having a substantially spherical shape is used as the
copper-based small-sized raw powder 3. The average diameter of the
copper-based small-sized raw powder 3 is in the range of 30 to 50
.mu.m, but is preferably 20 .mu.m.
[0039] Herewith, the average diameter of the copper-based flat raw
powder 2 becomes smaller than that of the iron-based raw powder 1,
and becomes larger than that of the copper-based small-sized raw
powder 3. Due to the above comparative difference in size, the
average value of the maximum projected area A of the copper-based
flat raw powder 2 becomes smaller than that of the maximum value of
the projected area B of the iron-based raw powder 1, and the
average value of the maximum projected area A becomes larger than
that of the maximum projected area C of the copper-based
small-sized raw powder 3.
[0040] As shown in FIG. 5, a bearing 5 has a substantially
cylindrical shape and a substantially cylindrical-shaped sliding
surface 51, on which a rotational shaft, which is a rotator (not
shown), rotationally slides, is formed at the center of the bearing
5. At both sides in the longitudinal direction of the sliding
surface 51, which is a sliding portion, flat end surfaces 52 and 53
are formed, and an outer circumferential surface 54 thereof is
formed like a cylindrical shape.
[0041] The mixture (mixed at S1) of the iron-based raw powder 1,
the copper-based flat raw powder 2, and the copper-based
small-sized raw powder 3 is filled into a filling portion 16 of a
forming mold 11. In the mixed powder filled into the filling
portion 16, a ratio of the copper-based flat raw powder is 20 to
40% by weight with respect to all raw powders.
[0042] FIG. 6 is an example of the forming mold 11. The forming
mold 11 includes a die 12, a core rod 13, a lower-side punch 14,
and an upper-side punch 15. A vertical direction of the forming
mold 11 is an axial direction (a vertical axial direction of the
press). The die 12 has a substantially cylindrical shape, and the
core rod 13 having a substantially cylindrical shape is coaxially
positioned in the die 12. The lower-side punch 14 has a
substantially cylindrical shape and is fitted between the die 12
and the core rod 13 from the lower side, so that the lower-side
punch 14 can move in the vertical direction. The upper punch 15 has
a substantially cylindrical shape and is fitted between the die 12
and the core rod 13 from the upper side, so that the upper-side
punch 15 can move in the vertical direction and in such a manner as
to be freely detachable. Furthermore, the filling portion 16 is
formed among the die 12, the core rod 13, and the lower-side punch
14. An inner circumferential surface of the die 12 forms the outer
circumferential surface 54. An upper surface of the lower-side
punch 14 forms the end surface 53. A lower surface of the
upper-side punch 15 forms the end surface 52. The outer
circumferential surface of the core rod 13 forms the sliding
surface 51.
[0043] As shown in FIG. 6, the mixture of the iron-based raw powder
1, the copper-based flat raw powder 2, and the copper-based
small-sized raw powder 3 is filled into the filling portion 16, and
a vibration is applied to the mixture of the raw materials 1 to 3
(S2). In this case, the upper side of the filling portion 16 is
closed by the upper-side punch 15, and vibration is applied to the
filling portion 16 at the accelerating speed of 0.01 to 3G without
pressing the punches 14 and 15. When the vibration is applied to
the filling portion 16, the copper-based flat raw powder 2, which
is flat powder, segregates at the outer side within the filling
portion 16, that is, at the sliding surface 51 or the outer
circumferential surface 54, overlaps each other in the thickness
direction, and gathers so as to make the direction intersecting the
thickness direction aligned with the longitudinal direction of the
surface. In addition, the iron-based raw powder 1 sometimes emerges
between the copper-based flat raw powders 2 as well as the
segregated copper-based flat raw powder 2 in the outer side within
the filling portion 16. However, the copper-based small-sized raw
powder 3A intrudes into the gap formed between the iron-based raw
powder 1 and the copper-based flat raw powder 2 and then emerges at
the outer side, or the copper-based small-sized raw powder 3B
intrudes into the gap formed between the copper-based flat raw
powders 2 and then emerges at the outer side. As a result, the
surface coverage ratio of copper in the sliding surface 51 becomes
80% or more, or 85% or more. The surface coverage ratio of copper
means the surface coverage ratio not including the hole region,
like the surface coverage ratio of copper in the latter related
art.
[0044] Furthermore, since the flat surface of the copper-based raw
powder 2 is wide, it is possible to segregate the copper-based raw
powder 2 at the outer side within the filling portion 16 by
generating static electricity on the surface of the forming mold 11
surrounding the filling portion 16, or it is possible to segregate
the copper-based raw powder 2 at the outer side within the filling
portion 16 by using magnetic force as well as the vibration.
[0045] On the other hand, the remaining copper-based flat raw
powder 2A at the inner side that has not segregated at the outer
side within the filling portion 16, that is, the sliding surface 51
and the outer circumferential surface 54 are disposed to surround
the iron-based raw powder 1 with the plurality of copper-based
small-sized raw powders 3.
[0046] Then, the upper-side and lower-side punches 15 and 14 press
the mixture of the raw powders 1 to 3 within the filling portion 16
to form a powder compact 6 (S3). As shown in FIG. 8, the
copper-based flat raw powder 2, which is a flat powder, emerges at
the surface, and the ratio of the iron-based raw powder 1 increases
as it goes toward the inner side of the powder compact 6. The
powder compact 6 is sintered (S4) to form a sintered bearing 5. A
post process such as a sizing process or an oil impregnation
process is performed on the bearing 5, if needed.
[0047] In the above embodiment, in accordance with the first
aspect, in the bearing 5 which is a sliding part formed by filling
the raw powder into the filling portion 16 of the forming mold 11,
compacting the raw powder to form a powder compact 6, and sintering
the powder compact 6, the copper-based raw powder is composed of
the copper-based flat raw powder 2 having an average diameter
smaller than that of the iron-based raw powder 1 and an aspect
ratio larger than that of the iron-based raw powder 1; and the
copper-based small-sized raw powder 3 having an average diameter
smaller than that of the copper-based flat raw powder 2, and the
copper is allowed to segregate at the surface of the sliding part.
Therefore, the copper-based raw powder 2, which is a flat powder,
and the iron-based raw powder 1 are filled into the filling portion
16, and the vibration is applied thereto, such that the
copper-based flat powder segregates at the surface. Furthermore, in
the obtained bearing 5, the surface is covered with the
copper-based small-sized raw powder 3 emerged on the surface as
well as the copper-based flat raw powder 2, thereby it is possible
to increase the surface coverage ratio of copper.
[0048] Therefore, the rotator slides on the sliding surface 51
which is covered with the copper, and the coefficient of friction
between the rotation axis and the sliding surface 51 becomes small,
thereby the rotation performs smoothly. In addition, the
predetermined strength and the durability can be obtained due to
the iron. Furthermore, in the above structure, even though the
sliding surface 51, on which the rotator rotates, is abraded, since
a predetermined ratio of copper is contained below the sliding
surface 51, the durability of the sliding portion becomes
excellent.
[0049] Furthermore, in the above embodiment, in accordance with the
second and sixth aspects, since the surface coverage ratio of
copper in the sliding surface 51, which is the sliding portion, is
80% or more, it is possible to suppress the coefficient of the
friction at a significantly lower level.
[0050] Furthermore, in the above embodiment, in accordance with the
third and ninth aspects, since the aspect ratio of the copper-based
flat raw powder 2 is set to 10 or more, when a vibration is
applied, the copper-based flat powder 2 segregates easily at the
surface, and it is possible to obtain the bearing 5 having a high
copper concentration at the surface.
[0051] Furthermore, in the above embodiment, in accordance with the
fourth aspect, since the ratio of the copper-based flat raw powder
2 is set in the range of 20% to 40%, it is possible to obtain a
bearing 5 having low frictional resistance and high strength.
[0052] Furthermore, in the above embodiment, in accordance with the
fifth aspect, in the bearing 5 formed by filling the raw powder
into the filling portion 16 of the forming mold 11, compacting the
raw powder to form the powder compact 6, and sintering the powder
compact 6, the copper-based raw powder is composed of the
copper-based flat raw powder 2 having an average value of the
maximum projected area A smaller than the average value of the
maximum projected area B of the iron-based raw powder 1 and an
aspect ratio larger than that of the iron-based raw powder 1; and
the copper-based small-sized raw powder 3 having the average value
of the maximum projected area C smaller than that of the maximum
projected area A of the copper-based flat raw powder 2, and the
copper is allowed to segregate at the surface of the sliding part.
Therefore, the copper-based raw powder 2, which is a flat powder,
and the iron-based raw powder 1 are filled into the filling portion
16, and the vibration is applied thereto, such that the
copper-based flat powder segregates at the surface. Furthermore, in
the obtained bearing 5, the surface is covered with the
copper-based small-sized raw powder 3 that has emerged on the
surface as well as the copper-based flat raw powder 2, thereby it
is possible to increase the surface coverage ratio of copper.
[0053] Furthermore, in the above embodiment, in accordance with the
seventh and eighth aspects, the surface is covered with the
copper-based small-sized raw powder 3 that has emerged at the
surface as well as the copper-based flat raw powder 2 appear, it is
possible to obtain the bearing 5, the surface coverage ratio of
copper of which increases.
[0054] Furthermore, in the above embodiment, in accordance with the
tenth aspect, since the ratio of the copper-based raw powder is set
in the range of 20% to 40% by weight with respect to all of the raw
powders, the frictional resistance decreases and it is possible to
obtain the sliding part having a high strength.
[0055] Furthermore, the present invention is not limited to the
above embodiment, and various modifications can be made. For
example, the flat powder can include a rod-shaped powder. In this
case, the ratio of the length and the diameter becomes the aspect
ratio.
INDUSTRIAL APPLICABILITY
[0056] The above sliding part and the method of manufacturing the
same according to the aspects of the invention can be applied to
various sliding parts in addition to the bearing.
* * * * *