U.S. patent application number 15/262650 was filed with the patent office on 2017-04-13 for method of manufacturing pipe member.
The applicant listed for this patent is OTICS CORPORATION. Invention is credited to Eiichi NOZAKI, Hiroya TSUJI, Koki YAMAGUCHI.
Application Number | 20170100766 15/262650 |
Document ID | / |
Family ID | 56800105 |
Filed Date | 2017-04-13 |
United States Patent
Application |
20170100766 |
Kind Code |
A1 |
YAMAGUCHI; Koki ; et
al. |
April 13, 2017 |
METHOD OF MANUFACTURING PIPE MEMBER
Abstract
A method of manufacturing a pipe member includes arranging a
pre-pipe member between first and second dies, moving one of the
first and second dies to be closer to another one and holding the
pre-pipe member with first and second recess portions, by the
moving of the one of the first and second dies, and pressing an
outer peripheral surface of the pre-pipe member with first and
second inner surfaces in a closed state of the dies. By the
pressing of the outer peripheral surface of the pre-pipe member,
reducing a diameter of a portion of the pre-pipe member and forming
a reduction portion having a polygonal shape so that the reduction
portion has a same number of outer surfaces as a total number of
the first inner surfaces and the second inner surfaces.
Inventors: |
YAMAGUCHI; Koki; (Aichi,
JP) ; NOZAKI; Eiichi; (Aichi, JP) ; TSUJI;
Hiroya; (Aichi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OTICS CORPORATION |
Aichi |
|
JP |
|
|
Family ID: |
56800105 |
Appl. No.: |
15/262650 |
Filed: |
September 12, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21D 53/845 20130101;
B21D 22/025 20130101; B21K 1/12 20130101 |
International
Class: |
B21D 53/84 20060101
B21D053/84; B21K 1/12 20060101 B21K001/12 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 7, 2015 |
JP |
2015-199126 |
Claims
1. A method of manufacturing a pipe member, the method comprising:
arranging a first die including a first recess portion that has
first inner surfaces and a second die including a second recess
portion that has second inner surfaces, such that the first recess
portion is opposite to the second recess portion; arranging a
pre-pipe member between the first die and the second die, the
pre-pipe member having an elongated tubular shape; and moving one
of the first die and the second die to be closer to another one of
the first die and the second die and holding the pre-pipe member
with the first recess portion and the second recess portion,
wherein the moving of the one of the first die and the second die
comprises pressing an outer peripheral surface of the pre-pipe
member with the first inner surfaces and the second inner surfaces
in a closed state where the first die and the second die are
closed, and the pressing of the outer peripheral surface of the
pre-pipe member comprises reducing a diameter of a portion of the
pre-pipe member and forming a reduction portion having a polygonal
shape so that the reduction portion has a same number of outer
surfaces as a total number of the first inner surfaces and the
second inner surfaces.
2. The method according to claim 1, wherein the polygonal shape is
a regular hexagonal shape, the first recess portion has three first
inner surfaces including two first side inner surfaces, and a first
recessed inner surface that is between the first side inner
surfaces, the second recess portion has three second inner surfaces
including two second side inner surfaces, and a second recessed
inner surface that is between the second side inner surfaces, the
arranging of the first die and the second die comprises arranging
the first die and the second die such that the first recessed inner
surface faces the second recessed inner surface, the pressing of
the outer peripheral surface comprises pressing the outer
peripheral surface of the pre-pipe member with the three first
inner surfaces and the three second inner surfaces, and in the
closed state where the first die and the second die are closed, a
distance Y between the first recessed inner surface and the second
recessed inner surface is from 0.77X to 0.95X where X is an outer
diameter of the pre-pipe member.
3. The method according to claim 1, wherein the pre-pipe member is
a shaft of a camshaft to be included in an engine.
4. The method according to claim 1, further comprising before the
pressing of the outer peripheral surface, holding portions of the
pre-pipe member with a holding member, the portions of the pre-pipe
member being near a portion of the pre-pipe member to be pressed
with the first die and the second die.
5. The method according to claim 4, wherein the holding member has
a tubular shape having a through hole therein, and the holding of
the portions comprises inserting the pre-pipe member in the through
hole.
6. The method according to claim 1, wherein the polygonal shape is
a regular hexagonal shape, the first recess portion has three first
inner surfaces including two first side inner surfaces, and a first
recessed inner surface that is between the first side inner
surfaces, the second recess portion has three second inner surfaces
including two second side inner surfaces, and a second recessed
inner surface that is between the second side inner surfaces, the
arranging of the first die and the second die comprises arranging
the first die and the second die such that the first recessed inner
surface faces the second recessed inner surface, and the pressing
of the outer peripheral surface comprises: pressing the outer
peripheral surface of the pre-pipe member with the first side inner
surfaces and the second side inner surfaces first and then,
according to further pressing of the outer peripheral surface, the
first recessed inner surface and the second recessed inner surface
being in contact with the outer peripheral surface; and pressing
the outer peripheral surface of the pre-pipe member with the first
side inner surfaces, the first recessed inner surface, the second
side inner surfaces, and the second recessed inner surface in the
closed state where the first die and the second die are closed, and
forming the reduction portion having a hexagonal cross-sectional
shape.
7. The method according to claim 6, wherein in the closed state, a
distance between the first recessed inner surface and the second
recessed inner surface is smaller than an outer diameter of the
pre-pipe member.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from Japanese Patent
Application No. 2015-199126 filed on Oct. 7, 2015. The entire
contents of the priority application are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present disclosure relates to a method of manufacturing
a pipe member.
BACKGROUND OF THE INVENTION
[0003] A pipe may have a tapered portion in a middle of a pipe path
or may have a portion having a hexagonal outer peripheral shape.
Specifically, swaging processing is carried out to reduce a
diameter of a part of a hollow exhaust pipe (a pipe member). Thus,
a tapered portion where an outer diameter of the pipe is gradually
reduced is formed.
SUMMARY OF THE INVENTION
[0004] However, if the pipe path is to be changed or the outer
peripheral shape of the pipe is to be changed with the swaging
process, the outer peripheral surface is continuously hit while
changing a phase of the pipe member, and an expensive, specialized
device is required. Pipe members are processed one by one by
changing an angle thereof with respect to a hitting device. The
pipe member may be bent during the swaging process depending on a
required processing accuracy. To prevent this from occurring, a
core bar is usually inserted into the pipe member. However, it
might not be possible to insert the core bar into the pipe member
due to the shape of the pipe.
[0005] The present technology has been made in view of the
aforementioned circumstances. An objective of the present
technology is to provide a method of manufacturing a pipe member
easily and with reduced cost.
[0006] To solve the above problem, according to the present
technology, a method of manufacturing a pipe member includes
arranging a first die including a first recess portion that has
first inner surfaces and a second die including a second recess
portion that has second inner surfaces such that the first recess
portion is opposite the second recess portion, arranging a pre-pipe
member between the first die and the second die, the pre-pipe
member having an elongated tubular shape, moving one of the first
die and the second die to be closer to another one of the first die
and the second die and holding the pre-pipe member with the first
recess portion and the second recess portion, by the moving of the
one of the first die and the second die, pressing an outer
peripheral surface of the pre-pipe member with the first inner
surfaces and the second inner surfaces in a closed state where the
first die and the second die are closed, by the pressing of the
outer peripheral surface of the pre-pipe member, reducing a
diameter of a portion of the pre-pipe member and forming a
reduction portion having a polygonal shape so that the reduction
portion has a same number of outer surfaces as a total number of
the first inner surfaces and the second inner surfaces.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view of a camshaft including a shaft
(a pipe member) manufactured with a method according to the present
technology.
[0008] FIG. 2 is a perspective view of a pre-pipe member during a
reduction process.
[0009] FIG. 3 is a cross-sectional view of the pre-pipe member
arranged between a first die and a second die during the reduction
process.
[0010] FIG. 4 is a cross-sectional view of the pre-pipe member
arranged between a first recess portion and a second recess portion
such that an outer peripheral surface of the pre-pipe member is in
contact with a part of the first inner surfaces and a part of the
second inner surfaces, and FIG. 4 is a cross-sectional view taken
along line V-V in FIG. 2.
[0011] FIG. 5 is a cross-sectional view of the pre-pipe member
between the first die and the second die that are closed.
[0012] FIG. 6 is a perspective view of a shaft including a
hexagonal portion.
[0013] FIG. 7 is a cross-sectional view of a shaft having a tapered
end portion and taken along VI-VI line in FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0014] One embodiment of the present technology will be described
with reference to FIGS. 1 to 7. A holding member 70 is not
described in FIGS. 3 to 5. A camshaft 340 described in FIG. 1 is
one of components included in an engine and includes one shaft (a
pipe member) 30. The shaft 30 collectively includes multiple cams
40 (41-48) that are configured to open or close intake and exhaust
valves included in the engine. The cams (41-48) are mounted on the
shaft 30 to be rotated integrally therewith. The shaft 30 includes
a hexagonal portion 55 having a regular hexagonal cross-sectional
shape between the adjacent cams 42 and 43 that are on a left side
in the drawing. When the cams 40 are mounted on the shaft 30, a
position of each cam 40 is adjusted with the hexagonal portion 55
being held between distal ends of a tool such as a wrench (not
illustrated). Specifically, opposite surfaces of the hexagonal
portion 55 having a hexagonal cross-sectional shape are in contact
with the distal ends of the tool. The hexagonal portion 55 is
formed by reducing a diameter of a pre-pipe member 50 having an
elongated tubular shape (cylindrical shape) and the diameter of the
pre-pipe member 50 is reduced in one end portion thereof to have
the hexagonal portion 55 having a hexagonal cross-sectional shape
(see FIG. 6).
[0015] A method of manufacturing the shaft 30 having the hexagonal
portion 55 illustrated in FIG. 6 will be described. First, an
elongated cylindrical tubular pre-pipe member 50 is manufactured.
STKM13C is used as a material of the pre-pipe member 50 and STKM is
a general material for a pipe member. The pre-pipe member 50 is
manufactured with ATKM13C to have an outer diameter of 25 mm and a
thickness of 3.5 mm. Then, the pre-pipe member 50 is subjected to a
reduction process, and a desired portion of the pre-pipe member
except for the end portions is subjected to the reduction process
so that the diameter thereof is reduced to have a regular hexagonal
cross-sectional shape.
[0016] As illustrated in FIGS. 2 to 5, a press molding device is
used in the reduction process and the press molding device includes
a first die 10 and a second die 20. The first die 10 is on an upper
side and the second die 20 is on a lower side. The first die 10
includes a first recess portion 10A on a surface 11 opposite the
second die 20 and the first recess portion 10A has multiple
surfaces. The multiple surfaces are three surfaces including first
side inner surfaces 101, 103 that are opposite each other and a
first recessed inner surface 102 that is between the first side
inner surfaces 101, 103. The first side inner surfaces 101, 103 and
the first recessed inner surface 102 correspond with three surfaces
of the hexagonal portion 55 that has a regular hexagonal
cross-sectional shape and is to be formed in a portion of the
pre-pipe member 50.
[0017] The second die 20 includes a second recess portion 20A on a
surface 21 opposite the first die 10 and the second recess portion
20A has multiple surfaces. The multiple surfaces are three surfaces
including second side inner surfaces 204, 206 and a second recessed
inner surface 205 that is between the second side inner surfaces
204, 206. The second side inner surfaces 204, 206 and the second
recessed inner surface 205 correspond with another three surfaces
of the hexagonal portion 55 that has a regular hexagonal shape and
is to be formed in a portion of the pre-pipe member 50.
Hereinafter, the general reference of the first inner surfaces
including the first side inner surfaces 101, 103 and the first
recessed inner surface 102 will be referred to as the first inner
surfaces 100 and the general reference of the second inner surfaces
including the second side inner surfaces 204, 206 and the second
recessed inner surface 205 will be referred to as the second inner
surfaces 200.
[0018] As illustrated in FIG. 5, the first die 10 and the second
die 20 are closed so that the regular hexagonal shape is defined by
the first inner surfaces 100 and the second inner surfaces 200. In
the closed state, the first inner surfaces 100 and the second inner
surfaces 200 are opposite each other, respectively, with a distance
of 22 mm between the opposite surfaces 100 and 200. Specifically,
as illustrated in FIG. 5, the first inner surface 101 is opposite
the second inner surface 204, the first inner surface 102 is
opposite the second inner surface 205, and the first inner surface
103 is opposite the second inner surface 206. The distance Y
between the respective first inner surfaces and the respective
second inner surfaces is 22 mm.
[0019] A ratio of the distance between the opposite surfaces to an
outer diameter X of the pre-pipe member 50 is approximately 0.88.
The opposite surfaces are the respective first inner surfaces 100
and the respective second inner surfaces 200 in the closed state of
the first die 10 and the second die 20. The distance Y between the
opposite surfaces is preferably from 0.77X to 0.95X with respect to
the outer diameter X of the pre-pipe member 50. The opposite
surfaces are the respective first inner surfaces 100 and the
respective second inner surfaces 200 in the closed state of the
first die 10 and the second die 20. If the distance Y between the
opposing surfaces is less than 0.77X, a part of the pre-pipe member
50 may go outside the molding recess portion. If the distance Y
between the opposing surfaces is greater than 0.95X, a desired
hexagonal shape may not be formed.
[0020] As illustrated in FIG. 3, the pre-pipe member 50 is arranged
between the first inner surfaces 100 of the first recess portion
10A of the first die 10 and the second inner surfaces 200 of the
second recess portion 20A of the second die 20 and then, the first
die 10 and the second die 20 are moved closer to each other and
closed. The first die 10 and the second die 20 are closed while
holding the pre-pipe member 50 between the first side inner
surfaces 101, 103 and the second side inner surfaces 204, 206, as
illustrated in FIG. 4. According to the closing of the dies 10, 20,
the pre-pipe member 50 is pressed by the first side inner surfaces
101, 103 and the second side inner surfaces 204, 206 so that the
outer peripheral surface of the pre-pipe member 50 is pressed
toward an axial center thereof. The first die 10 and the second 20
are further moved closer to each other, and the first recessed
inner surface 102 and the second recessed inner surface 205 are
brought in contact with the pre-pipe member 50 and the pre-pipe
member 50 is pressed by the first side inner surfaces 101, 103, the
first recessed inner surface 102, the second side inner surfaces
204, 206, and the second recessed inner surface 205. A load applied
to the pre-pipe member 50 in the closing of the first and second
dies 10, 20 is approximately 100 kN.
[0021] The distance Y between the opposing surfaces of the first
recess portion 10A and the second recess portion 20A in the closed
state of the dies 10 and 20 is 22 mm and the outer diameter X of
the pre-pipe member 50 is 25 mm. Thus, the outer diameter X of the
pre-pipe member 50 is greater than the distance Y between the
opposing surfaces. Therefore, as the first die 10 and the second
die 20 are moved closer to each other to be closed, the first side
inner surfaces 101, 103 and the second side inner surfaces 204, 206
are first in contact with the pre-pipe member 50 and press an outer
peripheral surface 50M of the pre-pipe member 50 so that a force Y1
is applied to the pre-pipe member 50 and contact portions of the
outer peripheral surface 50M start to be plastically deformed.
[0022] When the first die 10 and the second die 20 are moved closer
to each other to be completely closed and in a closed state, the
pre-pipe member 50 is further pressed and further plastically
deformed. Accordingly, the first inner surface 102 that is on an
upper side and the second inner surface 205 that is on a lower side
are in contact with the outer peripheral surface 50M of the
pre-pipe member 50 and contact portions of the pre-pipe member 50
in contact with the first inner surface 102 and the second inner
surface 205 are also plastically deformed.
[0023] Thus, when the first die 10 and the second die 20 are
closed, the first die 10 and the second die 20 apply pressure to
the outer peripheral surface 50M of the pre-pipe member 50 via the
first inner surfaces 100 and the second inner surfaces 200. In a
final closed state of the first die 10 and the second die 20, a
reduction portion of a polygonal cross-sectional shape is formed on
the outer peripheral surface of the pre-pipe member 50. The
polygonal shape is a hexagonal shape defined by the three first
inner surfaces 100 (101, 102, 103) and the three second inner
surfaces 200 (204, 205, 206). Accordingly, the shaft 30 includes
the hexagonal portion 55 on a part of the peripheral surface
thereof and the hexagonal portion 55 has a regular hexagonal
cross-sectional shape.
[0024] As illustrated in FIG. 2, in the reduction process, the
pre-pipe member 50 is inserted in a holding hole 70A of a holding
member 70. Specifically, a portion of the pre-pipe member 50 near
the portion that is to be pressed with the first die 10 and the
second die 20 is held by the holding member 70 from an outer
periphery of the pre-pipe member 50. The holding member 70 has an
elongated cylindrical tubular shape similar to the pre-pipe member
50 and has an inner diameter size that follows an outer diameter of
the pre-pipe member 50. Thus, the outer periphery of the pre-pipe
member 50 is held by the holding member 70. Therefore, the pre-pipe
member 50 is less likely to be bent when a load is applied thereto
from the first die 10 and the second die 20.
[0025] A hexagonal portion 255 is formed on a pre-pipe member
having a tapered end portion 250T to manufacture a shaft 230 as
illustrated in FIG. 7. In manufacturing such a shaft 230, the core
bar cannot be inserted in the shaft 230 and therefore, it is
effective to hold the portions of the pre-pipe member except for
the portion to be the hexagonal portion 255 with the holding member
70 from the outer periphery.
[0026] Next, operations and advantageous effects of the present
embodiments will be described.
[0027] According to the method of manufacturing the shaft 30, the
first die 10 and the second die 20 are closed and press the
pre-pipe member 50 from the outer periphery thereof so that a part
of the outer peripheral surface is processed to have the polygonal
shape on the outer peripheral surface 50M of the pre-pipe member 50
via one reduction process. Accordingly, time required for the
manufacturing process of the shaft 30 is shortened. A polygonal
portion is formed with the reduction process at a low cost compared
to a method using an expensive device that is exclusively used in
the swaging process.
[0028] According to the method of manufacturing the shaft 30, the
first die 10 has three surfaces for forming three surfaces of a
regular hexagonal shape of the hexagonal portion 55 and the second
die 20 has three surfaces for forming another three surfaces of the
regular hexagonal shape of the hexagonal portion 55. The opposing
surfaces of the first inner surfaces 100 and the second inner
surfaces 200 have the distance Y therebetween when the first die 10
and the second die 20 are closed, and the distance Y is from 0.77X
to 0.95X where X is the outer diameter of the pre-pipe member 50.
In the reduction process, when the first die 10 and the second die
20 are closed, pressure force is applied to the outer peripheral
surface of the pre-pipe member 50 via the three surfaces of the
first die 10 and the three surfaces of the second die 20.
Therefore, the pressure force is easily applied to the outer
peripheral surface 50M of the pre-pipe member 50 while holding the
outer peripheral surface 50M and a reduction portion having a
desired regular hexagonal cross-sectional shape is precisely formed
with the reduction process.
[0029] According to the method of manufacturing the shaft 30, the
hexagonal portion 55 (a polygonal reduction portion) is formed in a
middle portion of the shaft 30 that is an axis of the camshaft 340.
Therefore, the hexagonal portion 55 (polygonal reduction portion)
is useful in adjusting the positions of the cams 40.
[0030] According to the method of manufacturing the shaft 30, the
pre-pipe member 50 is held by the holding member 70 via the outer
periphery thereof. Therefore, the pre-pipe member 50 is less likely
to be deformed in executing the reduction process for the pre-pipe
member 50. Even in executing the reduction process for the pre-pipe
member 50 having the shape where the core bar cannot be inserted
therein, the pre-pipe member 50 is held by the holding member 70
from the outer peripheral surface thereof, and the pre-pipe member
50 is less likely to be bent.
* * * * *