U.S. patent application number 10/814088 was filed with the patent office on 2004-10-28 for cylindrical bearing member and method of manufacturing same.
Invention is credited to Matsuura, Tetsufumi.
Application Number | 20040213487 10/814088 |
Document ID | / |
Family ID | 32322188 |
Filed Date | 2004-10-28 |
United States Patent
Application |
20040213487 |
Kind Code |
A1 |
Matsuura, Tetsufumi |
October 28, 2004 |
Cylindrical bearing member and method of manufacturing same
Abstract
A small-bored cylindrical bearing member which can enhance the
maintainability for a lubricating oil therein. The member has blind
grooves in a seamless cylindrical central body portion of the
interior hollow cylindrical surface of the bearing member. A method
of manufacturing the cylindrical bearing member having blind
grooves with blocked-in end portions extending in the longitudinal
direction of the cylindrical portion and spaced from the ends of
the member. The grooves can be easily formed in the central body
portion of the inner circumferential cylindrical surface of the
central body portion with the blocked-in ends spaced from the
opposite ends of the seamless bearing member. The seamless member
is first formed with a tapered or flared portion at one open end
which is later narrowed into a round cylindrical form. Before
narrowing the tapered or flared portion, the blind grooves are
formed by a groove punch pushed through the open end into the
central body cylindrical portion. After narrowing, the blind
grooves have blocked end portions spaced from the opposite ends of
the bearing in the longitudinal direction.
Inventors: |
Matsuura, Tetsufumi; (Osaka,
JP) |
Correspondence
Address: |
DANN, DORFMAN, HERRELL & SKILLMAN
saet
1601 MARKET STREET
PHILADELPHIA
PA
19103-2307
US
|
Family ID: |
32322188 |
Appl. No.: |
10/814088 |
Filed: |
March 31, 2004 |
Current U.S.
Class: |
384/91 |
Current CPC
Class: |
F16C 33/1065 20130101;
Y10T 29/49636 20150115; Y10T 29/49668 20150115; Y10T 29/49673
20150115 |
Class at
Publication: |
384/091 |
International
Class: |
F16C 019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 25, 2003 |
JP |
2003-122217 |
Claims
1. A hollow cylindrical bearing member having an interior
cylindrical surface with a plurality of blind grooves in the
central body portion of said surface, each groove having blocked
end portions spaced from the opposite ends of said surface in the
longitudinal direction of the cylindrical surface, in parallel with
the axial direction of the cylindrical surface, said blind grooves
characterized by being forged by a groove punch in a forging
step.
2. A cylindrical bearing member according to claim 1, characterized
in that one end of said cylindrical bearing member beyond the
blocked ends of the grooves is characterized by having been first
flared outwardly and then decreased in diameter into a round
cylindrical end portion, said blind grooves being characterized by
having been formed with said groove punch pushed into the central
body portion from the one open end while in said tapered or flared
condition.
3. A small-bored hollow cylindrical bearing member having a
circumferential wall of a given thickness forming an interior
cylindrical surface with a plurality of blind grooves in the
central body portion of said surface, each groove having blocked
end portions spaced from the opposite ends of said surface in the
longitudinal direction of the cylindrical surface, said
longitudinal spacing being greater than said given thickness, said
blind grooves being in parallel with the axial direction of the
cylindrical surface, and characterized by having been forged by a
groove punch in a forging step.
4. A cylindrical bearing member according to claim 3, wherein said
circumferential wall forms a bore less than 50 mm. in diameter.
5. A cylindrical bearing member according to claim 4 wherein said
bore is in the range of 5 to 30 mm.
6. A cylindrical bearing member according to claim 5 wherein said
bore is about 6 mm.
7. A method of manufacturing a cylindrical bearing member of a
given length comprising the steps of: extruding a cylindrical
column-shaped metallic member having said given length to form a
primary intermediate article having a hollow cylindrical body
portion and a transverse bottom wall, press-fitting said primary
intermediate article into a die having one end flared by a flared
punch to form a secondary intermediate article having a flared end
portion open at one end of the cylindrical member in a flared
manner, pushing down a grooved punch from said one open end into
the inner central body portion of said secondary intermediate
article to form a tertiary intermediate article having a plurality
of blind grooves formed in the inner circumferential surface of
central body portion of the article, press-fitting said tertiary
intermediate article into a die whose inner circumferential surface
is circular to form a fourth intermediate forged article processed
in a round shape with said flared portion narrowed, and punching
out the bottom wall of said fourth intermediate forged article to
form a plurality of blind grooves each having blocked ends spaced
from the top and bottom ends of the article in the longitudinal
direction, parallel to the axial direction of the cylindrical body
portion.
8. A method according to claim 7 wherein said extruding step forms
a hollow cylindrical wall of a given thickness forming a bore of
less than 50 mm, and said flared end portion has an axial length
greater than said given thickness, whereby said blind grooves
terminate spaced from the top end of the article when the article
is processed into a round shape.
Description
TECHNICAL FIELD TO WHICH THE INVENTION PERTAINS
[0001] The present invention relates to a cylindrical bearing
member having a hollow cylindrical bore in which a plurality of
blind grooves, which provide reservoirs for a lubricating oil, were
formed in an endless inner circumferential surface of a cylindrical
bore in parallel to the axial direction of the cylindrical bore,
and a method of manufacturing the bearing member. Particularly, the
present invention relates to a bearing member having a cylindrical
bore in which these blind grooves were blocked without their ends
extending to either of the opposite ends of the cylindrical bore
and a method of manufacturing the bearing member in small
sizes.
BACKGROUND OF THE INVENTION
[0002] A cylindrical bearing member, which is used as sliding
bearings such as a bearing body for a rotating shaft, a bushing for
a chain and the like by inserting a shaft, a pin or the like into
the cylindrical bore of the article, has been conventionally well
known. As such, a cylindrical bearing member is well known, which
is provided with a plurality of grooves, which function as oil
reservoirs for a lubricating oil parallel to the axial direction of
the cylindrical bearing member, that is grooves, on an inner
circumferential surface of the cylindrical bearing member to
enhance the lubricating properties between the inner
circumferential surface in a cylindrical bore of the cylindrical
bearing member, which provides a bearing surface, and a shaft, or
between the cylindrical bore and a pin or the like.
[0003] In this conventional cylindrical bearing member, the grooves
are extended to both ends of the cylindrical bore so that they are
open on both ends of the cylindrical bore. Thus, when a shaft is
inserted into the cylindrical bore of the cylindrical bearing
member to use it as a bearing member while retaining a lubricating
oil in the grooves, the lubricating oil flows out of open ends in
the blind grooves. Accordingly, there were problems that the oil
reserve efficiency is bad and when this cylindrical bearing member
is used for a long period of time the lubricating properties are
deteriorated.
[0004] As a bearing member, which solved such a problem, a
cylindrical bearing member in which end portions of the respective
grooves in the longitudinal direction of the member were blocked to
form blind grooves, has been known (see Japanese Patent Publication
No. 2963652)
[0005] The above-mentioned known cylindrical bearing member 21 is
shown in FIG. 10. The cylindrical bearing member 21 is composed of
a cylindrical portion 24, in which a rectangular crude material 22
shown in FIG. 9 was wound into a cylindrical shape, that is, a
plurality of blind grooves 23 are formed by pressing, machining or
rolling on a surface of the rectangular crude material 22 such as a
band steel sheet, a steel sheet or the like, which provide oil
reservoirs. These blind grooves 23 are blocked on the respective
both ends 23a, 23a in the width direction of the crude material
such as a band steel sheet. Then the cylindrical bearing member 21
is wound into a cylindrical article (cylindrical portion) by a
machine so that both ends of the rectangular crude material such as
the band steel sheet are opposed, and a core punch is inserted into
this cylindrical article to push it into a circular shape to
manufacture a round cylindrical portion 24. In the thus
manufactured cylindrical bearing member 2, a seam 25 between butted
portions in the rectangular crude material 22 form a groove
portion.
[0006] Further, since the cylindrical bearing member 21 is formed
by winding, it is a comparatively thin member. However, as another
cylindrical bearing member comprising a thick cylindrical portion,
a cylindrical bearing member may be used in which blind grooves for
oil reservoirs were previously formed on an inner surface, that is
an inner circumferential surface (bearing surface) of a cylindrical
portion with a thick wall, whose outer surface was forged to a
round by undercutting, broaching or the like.
[0007] Japanese Patent Publication No. 2963652 also discloses a
conventional cylindrical bearing member which is formed by winding
a rectangular crude material so that the ends of the rectangular
crude material are in a butted state. Thus, there is a problem that
this butted portion forms a seam in the width direction of the
cylindrical portion. This seam provides a groove portion having no
bottom. Thus there is a problem that when this cylindrical bearing
member is used while inserting a shaft, a pin or the like into this
cylindrical bearing member, lubricating oil in the blind grooves
leaks on the side of the groove portion formed by the seam and
flows out of the ends in the longitudinal direction of the seam for
a very short time whereby the lubricating oil cannot be held for a
long period of time and the lubricating properties cannot be
maintained.
[0008] Further, there is a problem that since the cylindrical
portion of this cylindrical bearing member is formed by winding a
rectangular crude material, manufacturing of a cylindrical portion
having a thick wall is difficult and a thick cylindrical portion
cannot be formed.
[0009] Further, since in the above-mentioned conventional
cylindrical bearing member comprising a cylindrical portion having
a thick wall, and the blind grooves are formed on the inner
circumferential surface of the cylindrical portion by undercutting,
broaching or the like, the blind grooves cannot be formed by every
one blind groove only, whereby the formation efficiency of the
blind grooves are bad, a long time for its processing is needed and
the mass production is not suitable, which leads to disadvantageous
costs.
SUMMARY OF THE INVENTION
[0010] Accordingly, the objects of the present invention are to
solve the above-mentioned related art problems and to provide a
small cylindrical bearing member, in which maintainability for
lubricating oil filled in the blind grooves and oil reserving
efficiency can be enhanced by use of seamless cylindrical portion
of a cylindrical bearing member and a thin and a relatively thick
cylindrical portions can be used, as well as to provide a method of
manufacturing a cylindrical bearing member in which blind grooves
with blocked-in ends in the longitudinal direction of the
cylindrical portion can be efficiently formed on the inner
circumferential surfaces thereof.
[0011] The present invention has solved said problems based on the
concepts that the circumferential portion of a cylindrical bearing
member is made seamless and that ends of each blind groove for an
oil reservoir in the longitudinal direction are blocked to suppress
the oil flow out of the groove. The method of manufacturing the
cylindrical bearing member has solved said problems based on the
conception of forming blind grooves in which both ends of each
blind groove in the longitudinal direction of the cylindrical
bearing member were blocked by forming the blind grooves in a
forging step with a groove punch. Here the blind groove blocked at
both ends in the longitudinal direction of the cylindrical bearing
member means a blind groove both ends of which are spaced away from
the open ends of the cylindrical portion of the bearing member.
[0012] The bearing member of the present invention has a
configuration of a cylindrical bearing member characterized in that
a plurality of blind grooves, each having blocked end portions in
the longitudinal direction, are formed in the inner circumferential
surface of a seamless cylindrical portion in parallel with the
axial direction of the cylindrical portion and that said blind
grooves are forged, e.g., by a groove punch in a forging step.
[0013] The bearing embodying the present invention has a
configuration of a hollow cylindrical body portion with one end
metal-worked from an outwardly tapered or flared condition into a
round cylindrical portion. The interior of the central body portion
of the bearing has blind grooves, preferably forged while the one
end is in tapered or flared condition by a groove punch pushed into
the hollow interior of the central body portion from the open
tapered or flared end. After restoration of the one end to the
round cylindrical condition, the blind grooves are positioned
within the central body portion and have blocked ends spaced
inwardly from the open ends of the cylindrical bearing member.
[0014] The method of the present invention comprises a method of
manufacturing a cylindrical bearing member characterized by the
steps of: extruding a cylindrical column-shaped forging crude
material having required length to form a primary intermediate
forged article while leaving a bottom, press-fitting said primary
intermediate forged article into a die whose one end was formed in
a tapered manner with a tapered or flared punch to form a secondary
intermediate forged article having a tapered portion which was
opened at one end of the cylindrical portion in a tapered or flared
manner, pushing down a grooved punch from an opened end side into
the inner portion of an endless cylindrical portion of said
secondary intermediate forged article to form a tertiary
intermediate article in which a plurality of blind grooves were
formed in the inner circumferential surface of the article,
press-fitting said tertiary intermediate forged article into a die
whose inner circumferential surface is circular to form a fourth
intermediate forged article processed in a round shape with said
tapered or flared portion narrowed, and punching the bottom portion
of said fourth intermediate forged article to form a plurality of
blind grooves each having blocked ends in the longitudinal
direction of the article, in parallel to the axial direction of the
cylindrical portion.
[0015] According to one feature of the present invention, a
plurality of blind grooves, each blocked-in end portions in the
longitudinal direction, are formed in the inner circumferential
surface of an endless cylindrical portion in parallel with the
axial direction of the cylindrical portion. Thus, in a case where
the cylindrical bearing member was used as a sliding bearing by
inserting a shaft, a pin or the like into the cylindrical portion
of the member, a lubricating oil reserved in blind grooves is not
caused to flow out of ends of the cylindrical portion by its use
for a long period of time whereby excellent lubricating properties
are maintained. Further, since the blind grooves are formed with a
groove punch in a forging step, the blind grooves can be
efficiently formed.
[0016] According to another feature of the present invention,
before decreasing the diameter of a tapered portion opened at an
end of the cylindrical portion to process it to a round cylindrical
portion, the blind grooves are formed with the groove punch pushed
from an open end side of the tapered or flared portion into the
cylindrical portion. Thus, the blind grooves having blocked-in ends
in a seamless cylindrical portion in the axial direction, can be
efficiently formed on the inner circumferential surface of the
seamless cylindrical portion.
[0017] According to another aspect of the present invention, after
forming a cylindrical primary intermediate forged article to a
secondary intermediate forged article, a tapered or flared portion
in which one end of the article is opened in a tapered or flared
manner, a plurality of grooves are formed on the inner
circumferential surface of the secondary intermediate forged
article by pushing a groove punch into the surface to make a
tertiary intermediate forged article. Then this tertiary
intermediate forged article is press-fitted into a die having a
round inner circumferential surface to make a round fourth
intermediate forged article with a narrowed tapered or flared
portion. As a result a cylindrical bearing member having blind
grooves blocked-in at both ends of the cylindrical portion
respectively, can be manufactured.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a perspective view of a cylindrical bearing member
1 showing an example of the present invention.
[0019] FIG. 2 is a front view of a cylindrical column-shaped
starting material showing an example of the present invention.
[0020] FIG. 3 is a front view of the starting material of FIG. 2
with a modified end portion.
[0021] FIG. 4 is an explanatory view showing the modified starting
material being forged in accordance with the present invention.
[0022] FIG. 5 is an explanatory view showing the working of one end
of the material to form a tapered or flared end portion.
[0023] FIG. 6 is an explanatory view showing the formation of blind
grooves in the central body portion in accordance with the present
invention.
[0024] FIG. 7 is an explanatory view of working the flared end
portion to a round shape in accordance with the present
invention.
[0025] FIG. 8 is an explanatory view showing punching the bottom
portion at the end opposite to the flared end in accordance with
the present invention.
[0026] FIG. 9 is a perspective view of a rectangular crude material
before winding, showing a prior art example prior to being wound
into a cylinder.
[0027] FIG. 10 is a perspective view of a cylindrical bearing
member showing the completed prior art example.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] A cylindrical bearing member made in accordance with the
present invention is illustrated in FIGS. 1 and 8. The bearing
member 1 is a hollow cylinder 2 having an inner circumferential
surface 3. The interior surface 3 is provided with a plurality of
blind grooves 4 parallel to the axial direction of the hollow
cylindrical portion 2. As shown in FIG. 8, the blind grooves 4 are
formed in the central portion 3c of the inner cylindrical surface
of the cylindrical portion 2. The opposite ends of the central body
portion 3c are spaced from the open ends of the bearing member 1 to
form top portion 3a and bottom portion 3b. The blind grooves 4 are
confined to the central body portion 3c and terminate in blocked
ends 4a and 4b which are spaced inwardly from the open ends of the
cylindrical member 1 so that the end portions 3a and 3b of the
inner cylindrical surface are provided with a continuous
uninterrupted surface. The spacing from the open ends is preferably
greater than the thickness of the hollow cylindrical wall of
bearing member, so as to provide an effective barrier against
leakage of lubricant out of the bearing member beyond the blocked
ends of the grooves. The cylindrical bearing member is seamless as
shown in FIGS. 1 and 8.
[0029] In accordance with the present invention, the cylindrical
bearing member is formed in a series of metal-working steps with
the blind grooves being formed by a groove punch in a forging
step.
[0030] In the first step, a bar-shaped block of metallic starting
material, for example a high carbon chromium steel bar-shaped
starting material, was cut to the required length in accordance
with the length of a bearing member to be manufactured. The
starting material is in the form of a solid cylindrical
column-shaped component 5. One end of the starting block is
modified to the form shown at 6 in FIG. 3 for insertion into a
forming die 7 shown in FIG. 4. The end-modified starting block is
then extruded with a die 7 and an extruding punch 8 to form a
hollow cylindrical primary intermediate shaped article 9 which is
open at the top end and is closed at the bottom end by a bottom
wall 9a. Preferably, the intermediate article 9 is shaped by the
plastic flow of the metallic material.
[0031] A method of manufacturing the cylindrical bearing member 1
will be described. First, a bar-shaped metallic crude material, for
example a high-carbon chromium steel bar-shaped crude material was
cut to the required length in accordance with the size of a bearing
member to be manufactured to form cylindrical column-shaped forging
materials. In FIG. 2 only one cylindrical column-shaped forging
component 5 is shown. Then an end surface of this cylindrical
column-shaped forging component 5 was modified to form an
end-surface-corrected cylindrical column-shaped forging component 6
shown in FIG. 3.
[0032] Then, as shown in FIG. 4, the cylindrical column-shaped
forging component 6 was cold extruded with a die 7 and a extruding
punch 8 to form a cylindrical primary intermediate forged article 9
with a bottom portion 9a by the plastic flow of the metallic
material. The end-surface modification of the component 6
facilitates the insertion of the component into the die 7.
[0033] Then, as shown in FIG. 5, the cylindrical primary
intermediate shaped article 9 was press-fitted into a die 10 whose
one end was formed in a tapered or flared shape, with a tapered or
flared punch 11 to form a secondary intermediate forged article 12
having a tapered or flared portion 12b so that one end portion the
cylindrical portion 12a is opened or diverged in a tapered or
flared manner. It should be noted that the portion 12b is limited
to the upper end portion of the article 12 and does not extend into
the central body portion 12b of the article 12.
[0034] Then, as shown in FIG. 6, a groove punch 13 having convex
portions 13a was pushed into the cylindrical portion 12a from an
open side through the tapered or flared portion 12b in the
secondary intermediate forged article 12 with the secondary
intermediate forged article 12 held into the die 10, so that a
tertiary intermediate forged article 14 with a plurality of blind
grooves 4, parallel with the axial direction of the article and
formed on the entire inner circumference surface thereof, was
formed. In this case, the leading ends of the blind grooves 4 are
blocked by pushing the groove punch 13 to a lower end of the
cylindrical portion 12a of the secondary intermediate forged
article 12 so that the blind grooves are not penetrated.
[0035] Then, the tertiary intermediate forged article 14 having
blind grooves 4 in the cylindrical portion 12a and the tapered or
flared portion 12b was press-fitted into a die 15 having a round
inner circumferential surface with a pushing punch (not shown), as
shown in FIG. 7 to narrow the tapered or flared portion 12b in a
round shape and form a cylindrical fourth intermediate forged
article 16, the outer shape of which has become round. As mentioned
above the fourth intermediate forged article 16, which was formed
in a round shape, has blind grooves 4 on the inner circumferential
surface of the cylindrical portion 12a with the end portions of the
grooves blocked.
[0036] Finally, in the cylindrical fourth intermediate forged
article 16 in which the blind grooves were formed in the
above-mentioned forging step, the bottom wall 9a on the bottom
portion side of the article 16 was punched out so that an
open-ended cylindrical bearing member 1 having blind grooves 4 with
both ends blocked at 4a and 4b is completed.
[0037] Since in the cylindrical bearing member 1 manufactured in
the above-mentioned steps the cylindrical portion 2 has no seam and
both ends of the blind grooves formed on the inner circumferential
surface are blocked in the longitudinal direction of the member, in
a case where the cylindrical bearing member was used as a sliding
bearing by inserting a shaft, a pin or the like into the
cylindrical portion of the member, a lubricating oil reserved in
blind grooves is not caused to flow out of ends of the cylindrical
portion by its use for a long period of time whereby excellent
lubricating properties can be maintained. The method of the present
invention is particularly adapted to the manufacture of small-size
bearings whose internal bore is less than 50 mm. It has proved
particularly suited to making roller chain bearings whose internal
bores are in the range of 5 mm. to 30 mm. A popular size is 6
mm.
[0038] Further, according to the above-mentioned manufacturing
method, when the blind grooves 4 are formed on the inner
circumferential surface 3 of the cylindrical portion 2 in the
cylindrical bearing member 1, the seamless cylindrical primary
intermediate forged article is formed into the secondary
intermediate forged article having an one-end-opened, tapered or
flared portion is formed and a plurality of blind grooves are
formed on the inner circumferential surface by pushing a groove
punch, and then the tapered or flared portion is narrowed to form
in a round shape. Accordingly, blind grooves blocked at both ends
in the longitudinal direction of the cylindrical portion 2 can be
efficiently formed on the inner circumferential surface 3 of the
seamless cylindrical portion 2 whereby the cylindrical bearing
member 1 can be easily manufactured.
[0039] According to the present invention, in the cylindrical
bearing member, a plurality of blind grooves, each having blocked
end portions in the longitudinal direction, are formed in the inner
circumferential surface of a seamless cylindrical portion in
parallel with the axial direction of the cylindrical portion. Thus,
in a case where the cylindrical bearing member was used as a
sliding bearing by inserting a shaft, a pin or the like into the
cylindrical portion of the member, a lubricating oil reserved in
blind grooves is not caused to flow out of ends of the cylindrical
portion by its use for a long period of time whereby excellent
lubricating properties can be maintained. Further, since the blind
grooves are formed with a groove punch in a forging step, the blind
grooves can be efficiently formed, and the manufacturing of the
cylindrical bearing member having blind grooves can be easily
performed.
[0040] According to the present invention, before decreasing the
diameter of a tapered or flared portion open at an end of the
cylindrical portion to process it to a round cylindrical portion,
the blind grooves are formed with the groove punch pushed through
an open end of the tapered or flared portion into the cylindrical
body portion. Thus, the blind grooves, blocked-in the ends of a
seamless cylindrical portion in the axial direction, can be
efficiently formed on the inner circumferential surface of the
seamless cylindrical portion, and the manufacturing of the
cylindrical bearing member having such blind grooves can be easily
performed.
[0041] According to the present invention, the method of the
present invention comprises the steps of extruding a cylindrical
column-shaped member having the required length to form a primary
intermediate forged article while leaving a bottom wall,
press-fitting said primary intermediate forged article into a die
whose one end was formed in a tapered or flared manner with a
tapered or flared punch to form a secondary intermediate forged
article having a tapered or flared portion open at one end of the
cylindrical body portion in a tapered or flared manner, and pushing
down a grooved punch through the open side into the center body
portion of a seamless secondary intermediate forged article to form
a tertiary intermediate article in which a plurality of blind
grooves were formed in the inner circumferential surface of the
article at the center body portion. Thus, in the forging step a
number of blind grooves can be efficiently formed on the entire
inner circumferential surface of the cylindrical body portion.
Further, since the cylindrical portion can be formed in the forging
step, thin or thick wall cylindrical portion can be properly
formed.
[0042] Further, the method of the present invention includes the
steps of press-fitting said tertiary intermediate forged article,
in which a number of blind grooves were formed on the inner
circumferential surface of the cylindrical portion except for the
tapered or flared portion in the forging step, into a die whose
inner circumferential surface is circular to form a fourth
intermediate forged article processed in a round shape with said
tapered or flared portion narrowed, and punching the bottom wall of
said fourth intermediate forged article. Thus the hollow
cylindrical bearing member having a plurality of blind grooves,
blocked at both ends of the seamless cylindrical body portion, in
the longitudinal direction of the article, can be efficiently,
easily manufactured.
* * * * *