U.S. patent application number 14/241163 was filed with the patent office on 2015-06-25 for device and method for drawing metal tube.
This patent application is currently assigned to SHOWA DENKO K.K.. The applicant listed for this patent is Nobuhiko Hisata, Seiji Miyazaki, Keiichi Oinuma, Hidekazu Sakihama. Invention is credited to Nobuhiko Hisata, Seiji Miyazaki, Keiichi Oinuma, Hidekazu Sakihama.
Application Number | 20150174631 14/241163 |
Document ID | / |
Family ID | 47756245 |
Filed Date | 2015-06-25 |
United States Patent
Application |
20150174631 |
Kind Code |
A1 |
Sakihama; Hidekazu ; et
al. |
June 25, 2015 |
DEVICE AND METHOD FOR DRAWING METAL TUBE
Abstract
A device for drawing a metal tube capable of sufficiently
applying a lubricating oil to an inner surface of a tube at the
time of drawing and preventing occurrence of seizures is provided.
The device for drawing a metal tube in which drawing is performed
by making a metal blank tube 2 pass through between a die 10 for
forming an outer surface and a plug 11 for forming an inner surface
includes a control unit 31 configured to: measure an elapsed time
from a time at which supplying of a lubricating oil L to a surface
of the plug 11 is stopped until the metal blank tube 2 is set at a
drawing position between the die 10 and the plug 11 and becomes
ready to be drawn; control to not perform drawing of the metal
blank tube 2 when the measured elapsed time exceeds a preset
elapsed time; and control to initiate drawing of the metal blank
tube 2 when the measured elapsed time is within a preset allowed
time.
Inventors: |
Sakihama; Hidekazu;
(Oyama-shi, JP) ; Hisata; Nobuhiko; (Oyama-shi,
JP) ; Oinuma; Keiichi; (Oyama-shi, JP) ;
Miyazaki; Seiji; (Oyama-shi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sakihama; Hidekazu
Hisata; Nobuhiko
Oinuma; Keiichi
Miyazaki; Seiji |
Oyama-shi
Oyama-shi
Oyama-shi
Oyama-shi |
|
JP
JP
JP
JP |
|
|
Assignee: |
SHOWA DENKO K.K.
Minato-ku, Tokyo
JP
|
Family ID: |
47756245 |
Appl. No.: |
14/241163 |
Filed: |
August 28, 2012 |
PCT Filed: |
August 28, 2012 |
PCT NO: |
PCT/JP2012/071673 |
371 Date: |
March 10, 2015 |
Current U.S.
Class: |
72/20.1 |
Current CPC
Class: |
B21C 1/24 20130101; B21C
1/28 20130101; G03G 5/102 20130101; B21C 1/16 20130101; B21C 9/005
20130101; B21C 51/00 20130101; B21C 9/00 20130101; B21C 31/00
20130101; B21C 3/16 20130101 |
International
Class: |
B21C 31/00 20060101
B21C031/00; B21C 1/16 20060101 B21C001/16; B21C 51/00 20060101
B21C051/00; B21C 9/00 20060101 B21C009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 30, 2011 |
JP |
2011-186790 |
Claims
1. A device for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising a control unit configured to: measure an elapsed time
from a time at which supplying of a lubricating oil to a surface of
the plug is stopped until the metal blank tube is set at a drawing
position between the die and the plug and becomes ready to be
drawn; control to not perform drawing of the metal blank tube when
the measured elapsed time exceeds a preset allowed time; and
control to initiate drawing when the measured elapsed time is
within a preset allowed time.
2. A device for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising a control unit configured to: initiate a measurement of
an elapsed time from a time at which supplying of a lubricating oil
to a surface of the plug is stopped; control to stop an operation
of the device when a measuring elapsed time exceeds a preset
allowed time during a period of time from an initiation of the
measurement until the metal blank tube is set at a drawing position
between the die and the plug and becomes ready to be drawn, or at a
time at which it becomes ready to be drawn; and control to initiate
drawing when the measuring elapsed time is within the preset
allowed time at a time at which the metal blank tube is set at the
pulling position between the die and the plug and becomes ready to
be drawn.
3. A device for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising a control unit configured to: measure a first elapsed
time from a time at which supplying of a lubricating oil to a
surface of the plug is stopped until the plug is inserted into the
metal blank tube; control to stop an operation of the device when
the measured first elapsed time exceeds a preset first allowed
time; and control to continue an operation of the device when the
measured first elapsed time is within the preset first allowed
time, wherein the control unit is configured to: also measure a
second elapsed time from a time at which supplying of a lubricating
oil to a surface of the plug is stopped or from a time at which the
plug is inserted into the metal blank tube until the metal blank
tube is set at a drawing position between the die and the plug and
becomes ready to be drawn; control to not perform drawing of the
metal blank tube when the measured second elapsed time exceeds a
preset second allowed time; and control to initiate drawing when
the measured second elapsed time is within the preset second
allowed time.
4. A device for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising a control unit configured to: measure a first elapsed
time from a time at which supplying of a lubricating oil to a
surface of the plug is stopped until the plug is inserted into the
metal blank tube; control to stop an operation of the device when
the measured first elapsed time exceeds a preset first allowed
time; and control to continue an operation of the device when the
measured first elapsed time is within the preset first allowed
time, wherein the control unit is configured to: measure a second
elapsed time from a time at which supplying of a lubricating oil to
a surface of the plug is stopped or from a time at which the plug
is inserted into the metal blank tube; control to stop the
operation of the device when the measuring second elapsed time
exceeds a preset second allowed time during a period of time from
an initiation of the measurement until the metal blank tube is set
at a drawing position between the die and the plug and becomes
ready to be drawn, or at a time at which it becomes ready to be
drawn; and control to initiate drawing when the measuring second
elapsed time is within the preset second allowed time at a time at
which the metal blank tube is set at a pulling position between the
die and the plug and becomes ready to be drawn.
5. A device for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising a control unit configured to: initiate a measurement of
a first elapsed time from a time at which supplying of a
lubricating oil to a surface of the plug is stopped; control to
stop an operation of the device when the measuring first elapsed
time exceeds a preset first allowed time during a period of time
from an initiation of the measurement until the plug is inserted
into the metal blank tube, or at a time at which the plug is
inserted; and control to continue the operation of the device when
the measuring first elapsed time is within the preset first allowed
time at a time at which the plug is inserted into the metal blank
tube, wherein the control unit is configured to: also measure a
second elapsed time from a time at which supplying of a lubricating
oil to a surface of the plug is stopped or from a time at which the
plug is inserted into the metal blank tube until the metal blank
tube is set at a drawing position between the die and the plug and
becomes ready to be drawn; control to not perform drawing of the
metal blank tube when the measured second elapsed time exceeds a
preset second elapsed time; and control to initiate drawing when
the measured second elapsed time is within the second allowed
time.
6. A device for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising a control unit configured to: initiate a measurement of
a first elapsed time from a period of time at which supplying of a
lubricating oil to a surface of the plug is stopped; control to
stop an operation of the device when the measuring first elapsed
time exceeds a preset first allowed time during a period of time
from the initiation of the measurement until the plug is inserted
into the metal blank tube, or at a time at which the plug is
inserted; and control to continue the operation of the device when
the measuring first elapsed time is within the preset first allowed
time at a time at which the plug is inserted into the metal blank
tube, wherein the control unit is configured to: initiate a
measurement of a second elapsed time from a time at which supplying
of a lubricating oil to a surface of the plug is stopped or from a
time at which the plug is inserted into the metal blank tube;
control to stop the operation of the device when the measuring
second elapsed time exceeds a preset second allowed time during a
period of time from an initiation of the measurement until the
metal blank tube is set at a drawing position between the die and
the plug and becomes ready to be drawn, or at a time at which it
becomes ready to be drawn; and control to initiate drawing when the
measuring second elapsed time is within the preset second allowed
time at a time at which the metal blank tube is set at a pulling
position between the die and the plug and becomes ready to be
drawn.
7. A method for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising: an application step for applying a lubricating oil to a
surface of the plug and then stopping the supplying of the
lubricating oil; an insertion step for inserting and placing the
plug to which the lubricating oil was applied into the metal blank
tube; and a setting step for setting the metal blank tube at a
drawing position between the die and the plug; wherein it is
configured to: measure an elapsed time from a time at which
supplying of a lubricating oil to a surface of the plug is stopped
until the metal blank tube is set at a drawing position between the
die and the plug and becomes ready to be drawn is measured; control
to not perform drawing of the metal blank tube when the measured
elapsed time exceeds a preset allowed time; and control to perform
drawing of the metal blank tube when the measured elapsed time is
within a preset allowed time.
8. A method for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising: an application step for applying a lubricating oil to a
surface of the plug and then stopping the supplying of the
lubricating oil; an insertion step for inserting and placing the
plug to which the lubricating oil was applied into the metal blank
tube; and a setting step for setting the metal blank tube at a
drawing position between the die and the plug; wherein it is
controlled to: initiate a measurement of an elapsed time from a
time at which supplying of a lubricating oil to a surface of the
plug is stopped; control to stop an operation of a device when a
measuring elapsed time exceeds a preset allowed time during a
period of time from an initiation of the measurement until the
metal blank tube is set at a drawing position between the die and
the plug and becomes ready to be drawn, or at a time at which it
becomes ready to be drawn; and control to perform drawing when the
measuring elapsed time is within the preset allowed time at a time
at which the metal blank tube is set at a pulling position between
the die and the plug and becomes ready to be drawn.
9. A method for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising: an application step for applying a lubricating oil to a
surface of the plug and then stopping supplying of the lubricating
oil; an insertion step for inserting and placing the plug to which
the lubricating oil was applied into the metal blank tube; and a
setting step for setting the metal blank tube at a drawing position
between the die and the plug; wherein it is configured to: measure
a first elapsed time from a time at which supplying of a
lubricating oil to a surface of the plug is stopped until the plug
is inserted into the metal blank tube; control to stop an operation
of a device when the measured first elapsed time exceeds a preset
first allowed time; and control to continue the operation of the
device when the measured first elapsed time is within the preset
first allowed time, measure a second elapsed time from a time at
which supplying of a lubricating oil to a surface of the plug is
stopped or from a time at which the plug is inserted into the metal
blank tube until the metal blank tube is set at a drawing position
between the die and the plug and becomes ready to be drawn; control
to not perform drawing of the metal blank tube when the measured
second elapsed time exceeds a preset second allowed time; and
control to perform drawing when the measured second elapsed time is
within a preset second allowed time.
10. A method for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising: an application step for applying a lubricating oil to a
surface of the plug and then stopping supplying of the lubricating
oil; an insertion step for inserting and placing the plug to which
the lubricating oil was applied into the metal blank tube; and a
setting step for setting the metal blank tube at a drawing position
between the die and the plug; wherein it is configured to: measure
a first elapsed time from a time at which supplying of a
lubricating oil to a surface of the plug is stopped until the plug
is inserted into the metal blank tube; control to stop an operation
of a device when the measured first elapsed time exceeds a preset
first allowed time; control to continue an operation of the device
when the measured first elapsed time is within the preset first
allowed time; initiate a measurement of a second elapsed time from
a time at which supplying of a lubricating oil to a surface of the
plug is stopped or from a time at which the plug is inserted into
the metal blank tube; control to stop the operation of the device
when the measuring second elapsed time exceeds a preset second
allowed time during a period of time from an initiation of the
measurement until the metal blank tube is set at a drawing position
between the die and the plug and becomes ready to be drawn, or at a
time at which it becomes ready to be drawn; and perform drawing
when the measuring second elapsed time is within the preset second
allowed time at a time at which the metal blank tube is set at a
drawing position between the die and the plug and becomes ready to
be drawn.
11. A method for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising: an application step for applying a lubricating oil to a
surface of the plug and then stopping supplying of the lubricating
oil; an insertion step for inserting and placing the plug to which
the lubricating oil was applied into the metal blank tube; and a
setting step for setting the metal blank tube at a drawing position
between the die and the plug; wherein it is configured to: initiate
a measurement of a first elapsed time from a time at which
supplying of a lubricating oil to a surface of the plug is stopped;
control to stop an operation of a device when the measuring first
elapsed time exceeds a preset first allowed time during a period of
time from the initiation of the measurement until the plug is
inserted into the metal blank tube, or at a time at which the plug
is inserted; continue the operation of the device when the
measuring first elapsed time is within the preset first allowed
time at a time at which the plug is inserted into the metal blank
tube; measure a second elapsed time from a time at which supplying
of a lubricating oil to a surface of the plug is stopped or from a
time at which the plug is inserted into the metal blank tube until
the metal blank tube is set at a drawing position between the die
and the plug and becomes ready to be drawn; control to not perform
drawing of the metal blank tube when the measured second elapsed
time exceeds a preset second allowed time; and perform drawing when
the measured second elapsed time is within the second allowed
time.
12. A method for drawing a metal tube in which drawing is performed
by making a metal blank tube pass through between a die for forming
an outer surface and a plug for forming an inner surface,
comprising: an application step for applying a lubricating oil to a
surface of the plug and then stopping supplying of the lubricating
oil; an insertion step for inserting and placing the plug to which
the lubricating oil was applied into the metal blank tube; and a
setting step for setting the metal blank tube at a drawing position
between the die and the plug, wherein it is configured to: initiate
a measurement of a first elapsed time from a time at which
supplying of a lubricating oil to a surface of the plug is stopped;
control to stop an operation of a device when the measuring first
elapsed time exceeds a preset first allowed time during a period of
time from the initiation of the measurement until the plug is
inserted into the metal blank tube, or at a time at which the plug
is inserted; continue the operation of the device when the
measuring first elapsed time is within the preset first allowed
time at a time at which the plug is inserted into the metal blank
tube; initiate a measurement of a second elapsed time from a time
at which supplying of a lubricating oil to a surface of the plug is
stopped or from a time at which the plug is inserted into the metal
blank tube; control to stop the operation of the device when the
measuring second elapsed time exceeds a preset second allowed time
during a period of time from an initiation of the measurement until
the metal blank tube is set at a drawing position between the die
and the plug and becomes ready to be drawn, or at a time at which
it becomes ready to be drawn; and perform drawing when the
measuring second elapsed time is within the preset second allowed
time at a time at which the metal blank tube is set at a drawing
position between the die and the plug and becomes ready to be
drawn.
13. The method for drawing a metal tube as recited in claim 7,
wherein the application step, the insertion step, and the setting
step are performed in this order.
14. A method for producing a metal tube by performing drawing by
making a metal blank tube pass through between a die for forming an
outer surface and a plug for forming an inner surface, comprising:
an application step for applying a lubricating oil to a surface of
the plug and then stopping supplying of the lubricating oil; an
insertion step for inserting and placing the plug to which the
lubricating oil was applied into the metal blank tube; and a
setting step for setting the metal blank tube at a drawing position
between the die and the plug, wherein it is configured to: measure
an elapsed time from a time at which supplying of a lubricating oil
to a surface of the plug is stopped until the metal blank tube is
set at a drawing position between the die and the plug and becomes
ready to be drawn; control to not perform drawing of the metal
blank tube when the measured elapsed time exceeds a preset elapsed
time; and perform drawing of the metal blank tube when the measured
elapsed time is within a preset allowed time.
15. The method for producing a metal tube as recited in claim 14,
wherein the application step, the insertion step, and the setting
step are performed in this order.
16. The method for drawing a metal tube as recited in claim 8,
wherein the application step, the insertion step, and the setting
step are performed in this order.
17. The method for drawing a metal tube as recited in claim 9,
wherein the application step, the insertion step, and the setting
step are performed in this order.
18. The method for drawing a metal tube as recited in claim 10,
wherein the application step, the insertion step, and the setting
step are performed in this order.
19. The method for drawing a metal tube as recited in claim 11,
wherein the application step, the insertion step, and the setting
step are performed in this order.
20. The method for drawing a metal tube as recited in claim 12,
wherein the application step, the insertion step, and the setting
step are performed in this order.
Description
TECHNICAL FIELD
[0001] The present invention relates to a device and a method for
drawing a metal tube, capable of producing a drawn tube excellent
in dimensional accuracy suitably used as a substrate for an OPC
photosensitive drum for use in, for example, an electrophotographic
device such as a copying machine, a laser beam printer, a facsimile
device, etc.
[0002] In the description of this specification, the language of
"rear" in the drawing method and the drawing device is used to
include the meaning of the direction toward the blank tube side
with respect to the drawn tube, and the language of "front" means
the direction toward the toward tube side with respect to the blank
tube.
TECHNICAL BACKGROUND
[0003] In recent years, as an OPC photosensitive drum substrate for
use in, for example, an electrophotographic device such as a
copying machine, a laser beam printer, a facsimile device, etc.,
uncut tubes suitable for mass production has been used widely. As
one of uncut tubes, there is an ED tube obtained by drawing an
aluminum extruded blank tube. Such an ED tube is suitable for mass
production in that a plurality of tube products can be produced in
a single drawing process, and the method has attracted attention as
a method which can meet the need of mass consumption caused by
market expansion.
[0004] Such an ED tube is manufactured by initially obtaining an
aluminum extruded blank tube by extruding an aluminum billet,
cutting the extruded blank tube into a predetermined length, then
drawing the cut tube in one or two or more passes by a die and a
plug to obtain an aluminum tube having a predetermined shape (outer
diameter, inner diameter, and wall thickness), thereafter cutting
the aluminum tube, chamfering the cut edge portions thereof,
cleaning, and inspecting the dimension and appearance.
[0005] In a drawing process of such an aluminum tube for a
photosensitive drum substrate, for supplying a lubricating oil onto
an outer surface of a blank tube, it is easy to apply a lubricating
oil in advance or make a lubricating oil flow down during the
drawing process as necessary. However, when supplying a lubricating
oil to an inner surface of a blank tube, especially in the case of
an ED tube in which a blank tube is continuously drawn at a high
speed for two or passes, it is difficult to provide a lubricating
oil onto an inner surface of a blank tube in advance. Therefore,
there is no other choice other than applying a lubricating oil to a
plug, inserting the plug into a blank tube, and then performing a
drawing process as it is. Therefore, contrary to an outer surface
of a blank tube to which a lubricating oil can be supplied as
necessary, on an inner surface of a blank tube, a lubricating oil
tends to become insufficient during the drawing, causing occurrence
of seizures, which results in deterioration of the drawn tube swing
accuracy.
[0006] To solve these problems, the applicant proposed drawing
devices in which an opening portion is formed in a peripheral wall
of a hollow rod supporting a plug to eject a lubricating oil
supplied from a rear end portion of the rod to an inside of the rod
through the opening portion so that the lubricating oil can be
supplied as necessary to an inner surface of the blank tube. In
these drawing devices, a core for evenly spreading the lubricating
oil adhered to the inner surface of the blank tube is attached to
the rod (Patent Documents 1 and 2).
PRIOR ART DOCUMENTS
Patent Document
[0007] Patent Document 1: Japanese Unexamined Laid-opened Patent
Application Publication No. 2009-22982
[0008] Patent Document 2: Japanese Unexamined Laid-opened Patent
Application Publication No. 2009-45663
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0009] In the technologies as described in the aforementioned
Patent Documents 1 and 2, however, a large amount of lubricating
oil adheres to portions (e.g., a core) other than the plug when
supplying the lubricating oil to the inner surface of the blank
tube, thereby increasing the amount of lubricating oil which
remains inside the tube. This caused an increased amount of
consumption of lubricating oil.
[0010] Also, as explained above, in a drawing method in which a
plug to which a lubricating oil was applied is inserted into a
blank tube, seizures sometimes occur due to insufficient
lubricating oil on the inner surface of the blank tube. Occurrence
of such seizures not only causes scrapes but also provides cause of
deterioration of dimensional accuracy by processing heat. Shortage
of lubricating oil more likely occurs when the length of the blank
tube is longer and the drawing rate is faster. Therefore, in order
to increase the productivity of an ED tube by drawing a long blank
tube at a high drawing rate, the problem of the inner surface
seizures must be overcome. In addition, shortage of lubricating oil
on an inner surface of a blank tube when applying a lubricating oil
on a plug is especially notable when drawing in a horizontal
direction (that is, when drawing in a horizontal direction, the
lubricating oil especially on the upper side of the inner surface
of the blank tube tends to become insufficient).
[0011] The present invention was made in view of the aforementioned
technical background, and aims to provide a drawing device and a
drawing method for a metal tube capable of sufficiently applying a
lubricating oil to an inner surface of the tube at the time of
drawing to prevent occurrence of seizures.
Means for Solving the Problems
[0012] To achieve the aforementioned objects, the present invention
provides the following means.
[0013] [1] A device for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising a control unit configured to:
[0014] measure an elapsed time from a time at which supplying of a
lubricating oil to a surface of the plug is stopped until the metal
blank tube is set at a drawing position between the die and the
plug and becomes ready to be drawn;
[0015] control to not perform drawing of the metal blank tube when
the measured elapsed time exceeds a preset allowed time; and
[0016] control to initiate drawing when the measured elapsed time
is within a preset allowed time.
[0017] [2] A device for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising a control unit configured to:
[0018] initiate a measurement of an elapsed time from a time at
which supplying of a lubricating oil to a surface of the plug is
stopped;
[0019] control to stop an operation of the device when a measuring
elapsed time exceeds a preset allowed time during a period of time
from an initiation of the measurement until the metal blank tube is
set at a drawing position between the die and the plug and becomes
ready to be drawn, or at a time at which it becomes ready to be
drawn; and
[0020] control to initiate drawing when the measuring elapsed time
is within the preset allowed time at a time at which the metal
blank tube is set at the pulling position between the die and the
plug and becomes ready to be drawn.
[0021] [3] A device for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising a control unit configured to:
[0022] measure a first elapsed time from a time at which supplying
of a lubricating oil to a surface of the plug is stopped until the
plug is inserted into the metal blank tube;
[0023] control to stop an operation of the device when the measured
first elapsed time exceeds a preset first allowed time; and
[0024] control to continue an operation of the device when the
measured first elapsed time is within the preset first allowed
time,
[0025] wherein the control unit is configured to: [0026] also
measure a second elapsed time from a time at which supplying of a
lubricating oil to a surface of the plug is stopped or from a time
at which the plug is inserted into the metal blank tube until the
metal blank tube is set at a drawing position between the die and
the plug and becomes ready to be drawn;
[0027] control to not perform drawing of the metal blank tube when
the measured second elapsed time exceeds a preset second allowed
time; and
[0028] control to initiate drawing when the measured second elapsed
time is within the preset second allowed time.
[0029] [4] A device for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising a control unit configured to:
[0030] measure a first elapsed time from a time at which supplying
of a lubricating oil to a surface of the plug is stopped until the
plug is inserted into the metal blank tube;
[0031] control to stop an operation of the device when the measured
first elapsed time exceeds a preset first allowed time; and
[0032] control to continue an operation of the device when the
measured first elapsed time is within the preset first allowed
time,
[0033] wherein the control unit is configured to:
[0034] measure a second elapsed time from a time at which supplying
of a lubricating oil to a surface of the plug is stopped or from a
time at which the plug is inserted into the metal blank tube;
[0035] control to stop the operation of the device when the
measuring second elapsed time exceeds a preset second allowed time
during a period of time from an initiation of the measurement until
the metal blank tube is set at a drawing position between the die
and the plug and becomes ready to be drawn, or at a time at which
it becomes ready to be drawn; and
[0036] control to initiate drawing when the measuring second
elapsed time is within the preset second allowed time at a time at
which the metal blank tube is set at a pulling position between the
die and the plug and becomes ready to be drawn.
[0037] [5] A device for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising a control unit configured to:
[0038] initiate a measurement of a first elapsed time from a time
at which supplying of a lubricating oil to a surface of the plug is
stopped;
[0039] control to stop an operation of the device when the
measuring first elapsed time exceeds a preset first allowed time
during a period of time from an initiation of the measurement until
the plug is inserted into the metal blank tube, or at a time at
which the plug is inserted; and
[0040] control to continue the operation of the device when the
measuring first elapsed time is within the preset first allowed
time at a time at which the plug is inserted into the metal blank
tube,
[0041] wherein the control unit is configured to:
[0042] also measure a second elapsed time from a time at which
supplying of a lubricating oil to a surface of the plug is stopped
or from a time at which the plug is inserted into the metal blank
tube until the metal blank tube is set at a drawing position
between the die and the plug and becomes ready to be drawn;
[0043] control to not perform drawing of the metal blank tube when
the measured second elapsed time exceeds a preset second elapsed
time; and
[0044] control to initiate drawing when the measured second elapsed
time is within the second allowed time.
[0045] [6] A device for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising a control unit configured to:
[0046] initiate a measurement of a first elapsed time from a period
of time at which supplying of a lubricating oil to a surface of the
plug is stopped;
[0047] control to stop an operation of the device when the
measuring first elapsed time exceeds a preset first allowed time
during a period of time from the initiation of the measurement
until the plug is inserted into the metal blank tube, or at a time
at which the plug is inserted; and
[0048] control to continue the operation of the device when the
measuring first elapsed time is within the preset first allowed
time at a time at which the plug is inserted into the metal blank
tube,
[0049] wherein the control unit is configured to:
[0050] initiate a measurement of a second elapsed time from a time
at which supplying of a lubricating oil to a surface of the plug is
stopped or from a time at which the plug is inserted into the metal
blank tube;
[0051] control to stop the operation of the device when the
measuring second elapsed time exceeds a preset second allowed time
during a period of time from an initiation of the measurement until
the metal blank tube is set at a drawing position between the die
and the plug and becomes ready to be drawn, or at a time at which
it becomes ready to be drawn; and
[0052] control to initiate drawing when the measuring second
elapsed time is within the preset second allowed time at a time at
which the metal blank tube is set at a pulling position between the
die and the plug and becomes ready to be drawn.
[0053] [7] A method for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising:
[0054] an application step for applying a lubricating oil to a
surface of the plug and then stopping the supplying of the
lubricating oil;
[0055] an insertion step for inserting and placing the plug to
which the lubricating oil was applied into the metal blank tube;
and
[0056] a setting step for setting the metal blank tube at a drawing
position between the die and the plug;
[0057] wherein it is configured to:
[0058] measure an elapsed time from a time at which supplying of a
lubricating oil to a surface of the plug is stopped until the metal
blank tube is set at a drawing position between the die and the
plug and becomes ready to be drawn is measured;
[0059] control to not perform drawing of the metal blank tube when
the measured elapsed time exceeds a preset allowed time; and
[0060] control to perform drawing of the metal blank tube when the
measured elapsed time is within a preset allowed time.
[0061] [8] A method for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising:
[0062] an application step for applying a lubricating oil to a
surface of the plug and then stopping the supplying of the
lubricating oil;
[0063] an insertion step for inserting and placing the plug to
which the lubricating oil was applied into the metal blank tube;
and
[0064] a setting step for setting the metal blank tube at a drawing
position between the die and the plug;
[0065] wherein it is controlled to:
[0066] initiate a measurement of an elapsed time from a time at
which supplying of a lubricating oil to a surface of the plug is
stopped;
[0067] control to stop an operation of a device when a measuring
elapsed time exceeds a preset allowed time during a period of time
from an initiation of the measurement until the metal blank tube is
set at a drawing position between the die and the plug and becomes
ready to be drawn, or at a time at which it becomes ready to be
drawn; and
[0068] control to perform drawing when the measuring elapsed time
is within the preset allowed time at a time at which the metal
blank tube is set at a pulling position between the die and the
plug and becomes ready to be drawn.
[0069] [9] A method for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising:
[0070] an application step for applying a lubricating oil to a
surface of the plug and then stopping supplying of the lubricating
oil;
[0071] an insertion step for inserting and placing the plug to
which the lubricating oil was applied into the metal blank tube;
and
[0072] a setting step for setting the metal blank tube at a drawing
position between the die and the plug;
[0073] wherein it is configured to:
[0074] measure a first elapsed time from a time at which supplying
of a lubricating oil to a surface of the plug is stopped until the
plug is inserted into the metal blank tube;
[0075] control to stop an operation of a device when the measured
first elapsed time exceeds a preset first allowed time; and
[0076] control to continue the operation of the device when the
measured first elapsed time is within the preset first allowed
time,
[0077] measure a second elapsed time from a time at which supplying
of a lubricating oil to a surface of the plug is stopped or from a
time at which the plug is inserted into the metal blank tube until
the metal blank tube is set at a drawing position between the die
and the plug and becomes ready to be drawn;
[0078] control to not perform drawing of the metal blank tube when
the measured second elapsed time exceeds a preset second allowed
time; and
[0079] control to perform drawing when the measured second elapsed
time is within a preset second allowed time.
[0080] [10] A method for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising:
[0081] an application step for applying a lubricating oil to a
surface of the plug and then stopping supplying of the lubricating
oil;
[0082] an insertion step for inserting and placing the plug to
which the lubricating oil was applied into the metal blank tube;
and
[0083] a setting step for setting the metal blank tube at a drawing
position between the die and the plug;
[0084] wherein it is configured to:
[0085] measure a first elapsed time from a time at which supplying
of a lubricating oil to a surface of the plug is stopped until the
plug is inserted into the metal blank tube;
[0086] control to stop an operation of a device when the measured
first elapsed time exceeds a preset first allowed time;
[0087] control to continue an operation of the device when the
measured first elapsed time is within the preset first allowed
time;
[0088] initiate a measurement of a second elapsed time from a time
at which supplying of a lubricating oil to a surface of the plug is
stopped or from a time at which the plug is inserted into the metal
blank tube;
[0089] control to stop the operation of the device when the
measuring second elapsed time exceeds a preset second allowed time
during a period of time from an initiation of the measurement until
the metal blank tube is set at a drawing position between the die
and the plug and becomes ready to be drawn, or at a time at which
it becomes ready to be drawn; and
[0090] perform drawing when the measuring second elapsed time is
within the preset second allowed time at a time at which the metal
blank tube is set at a drawing position between the die and the
plug and becomes ready to be drawn.
[0091] [11] A method for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising:
[0092] an application step for applying a lubricating oil to a
surface of the plug and then stopping supplying of the lubricating
oil;
[0093] an insertion step for inserting and placing the plug to
which the lubricating oil was applied into the metal blank tube;
and
[0094] a setting step for setting the metal blank tube at a drawing
position between the die and the plug;
[0095] wherein it is configured to:
[0096] initiate a measurement of a first elapsed time from a time
at which supplying of a lubricating oil to a surface of the plug is
stopped;
[0097] control to stop an operation of a device when the measuring
first elapsed time exceeds a preset first allowed time during a
period of time from the initiation of the measurement until the
plug is inserted into the metal blank tube, or at a time at which
the plug is inserted;
[0098] continue the operation of the device when the measuring
first elapsed time is within the preset first allowed time at a
time at which the plug is inserted into the metal blank tube;
[0099] measure a second elapsed time from a time at which supplying
of a lubricating oil to a surface of the plug is stopped or from a
time at which the plug is inserted into the metal blank tube until
the metal blank tube is set at a drawing position between the die
and the plug and becomes ready to be drawn;
[0100] control to not perform drawing of the metal blank tube when
the measured second elapsed time exceeds a preset second allowed
time; and
[0101] perform drawing when the measured second elapsed time is
within the second allowed time.
[0102] [12] A method for drawing a metal tube in which drawing is
performed by making a metal blank tube pass through between a die
for forming an outer surface and a plug for forming an inner
surface, comprising:
[0103] an application step for applying a lubricating oil to a
surface of the plug and then stopping supplying of the lubricating
oil;
[0104] an insertion step for inserting and placing the plug to
which the lubricating oil was applied into the metal blank tube;
and
[0105] a setting step for setting the metal blank tube at a drawing
position between the die and the plug,
[0106] wherein it is configured to:
[0107] initiate a measurement of a first elapsed time from a time
at which supplying of a lubricating oil to a surface of the plug is
stopped;
[0108] control to stop an operation of a device when the measuring
first elapsed time exceeds a preset first allowed time during a
period of time from the initiation of the measurement until the
plug is inserted into the metal blank tube, or at a time at which
the plug is inserted;
[0109] continue the operation of the device when the measuring
first elapsed time is within the preset first allowed time at a
time at which the plug is inserted into the metal blank tube;
[0110] initiate a measurement of a second elapsed time from a time
at which supplying of a lubricating oil to a surface of the plug is
stopped or from a time at which the plug is inserted into the metal
blank tube;
[0111] control to stop the operation of the device when the
measuring second elapsed time exceeds a preset second allowed time
during a period of time from an initiation of the measurement until
the metal blank tube is set at a drawing position between the die
and the plug and becomes ready to be drawn, or at a time at which
it becomes ready to be drawn; and
[0112] perform drawing when the measuring second elapsed time is
within the preset second allowed time at a time at which the metal
blank tube is set at a drawing position between the die and the
plug and becomes ready to be drawn.
[0113] [13] The method for drawing a metal tube as recited in any
one of the aforementioned Items 7 to 12, wherein the application
step, the insertion step, and the setting step are performed in
this order.
[0114] [14] A method for producing a metal tube by performing
drawing by making a metal blank tube pass through between a die for
forming an outer surface and a plug for forming an inner surface,
comprising:
[0115] an application step for applying a lubricating oil to a
surface of the plug and then stopping supplying of the lubricating
oil;
[0116] an insertion step for inserting and placing the plug to
which the lubricating oil was applied into the metal blank tube;
and
[0117] a setting step for setting the metal blank tube at a drawing
position between the die and the plug,
[0118] wherein it is configured to:
[0119] measure an elapsed time from a time at which supplying of a
lubricating oil to a surface of the plug is stopped until the metal
blank tube is set at a drawing position between the die and the
plug and becomes ready to be drawn;
[0120] control to not perform drawing of the metal blank tube when
the measured elapsed time exceeds a preset allowed time; and
[0121] perform drawing of the metal blank tube when the measured
elapsed time is within a preset allowed time.
[0122] [15] The method for producing a metal tube as recited in the
aforementioned Item 14, wherein the application step, the insertion
step, and the setting step are performed in this order.
Effects of the Invention
[0123] In the following explanation of the effects of the
invention, the effects in the case of performing a drawing process
by drawing a metal blank tube in a horizontal direction are
explained for an easy understanding of the effects of the invention
(that is, the effects are explained by focusing on whether or not
an amount of a lubricating oil is enough on an upper side of an
inner surface of a blank tube). However, the present invention is
not especially limited to the case in which a drawing process is
performed by drawing in a horizontal direction.
[0124] In the invention [1], a control unit is provided. The
control unit is configured to: measure an elapsed time from a time
at which supplying of a lubricating oil to a surface of the plug is
stopped until the metal blank tube is set at a drawing position
between the die and the plug and becomes ready to be drawn; control
to not perform drawing of the metal blank tube when the measured
elapsed time exceeds a preset elapsed time; and control to initiate
the drawing when the measured elapsed time is within a preset
allowed time.
[0125] Therefore, for a blank tube in a state in which the amount
of the lubricating oil on the upper side of the inner surface of
the blank tube has decreased since it took time (it exceeded the
allowed time) until it becomes ready to be drawn, it can be
controlled to not perform drawing. Further, for a blank tube in
which the elapsed time until it becomes ready to be drawn is within
the allowed time and there exists a sufficient amount of
lubricating oil on the upper side of the inner surface of the blank
tube, it can be controlled to perform drawing. Therefore, it is
possible to produce a drawn tube having no seizures (a drawn tube
having seizures will not be produced).
[0126] In the invention [2], a control unit is provided. The
control unit is configured to: initiate a measurement of an elapsed
time from a time at which supplying of a lubricating oil to a
surface of the plug is stopped; control to stop an operation of the
drawing device when a measuring elapsed time exceeds a preset
allowed time during a period of time from an initiation of the
measurement until the metal blank tube is set at a drawing position
between the die and the plug and becomes ready to be drawn or at a
time at which it becomes ready to be drawn; and control to initiate
drawing when the measuring elapsed time is within the preset
allowed time at a time at which the metal blank tube is set at a
pulling position between the die and the plug and becomes ready to
be drawn.
[0127] Therefore, the operation of the device is stopped when the
elapsed time exceeds the allowed time during a period of time until
it becomes ready to be drawn, or at a time at which it becomes
ready to be drawn. Further, drawing is performed for a blank tube
in which the elapsed time until it becomes ready to be drawn is
within the allowed time and there exists a sufficient amount of
lubricating oil on the upper side of the inner surface of the blank
tube.
[0128] Therefore, a drawn tube having no seizures can be produced
(a drawn tube having seizures will not be formed).
[0129] In the invention [3], a control unit is provided. The
control unit is configured to: measure a first elapsed time from a
time at which supplying of a lubricating oil to a surface of the
plug is stopped until the plug is inserted into the metal blank
tube; control to stop an operation of the drawing device when the
measured first elapsed time exceeds a preset first allowed time;
and control to continue an operation of the drawing device when the
measured first elapsed time is within the preset first allowed
time.
[0130] Therefore, the operation of the device can be stopped when
an amount of the lubricating oil carried into the metal blank tube
from the plug is not sufficiently secured, and the operation of the
device can be continued as it is when an amount of the lubricating
oil carried into the metal blank tube from the plug is sufficiently
secured.
[0131] Further, the control unit is configured to: also measure a
second elapsed time from a time at which supplying of a lubricating
oil to a surface of the plug is stopped or at a time at which the
plug is inserted into the metal blank tube until the metal blank
tube is set at a drawing position between the die and the plug and
becomes ready to be drawn; control to not perform drawing of the
metal blank tube when the measured second elapsed time exceeds a
preset second allowed time; and control to initiate drawing when
the measured second elapsed time is within a preset second allowed
time.
[0132] Therefore, for a blank tube in a state in which the mount of
the lubricating oil on the upper side of the inner surface of the
blank tube has decreased since it took time (it exceeded the second
allowed time) until it becomes ready to be drawn, it can be
controlled to not perform drawing. Further, for a blank tube in
which the second elapsed time until it becomes ready to be drawn is
within the second allowed time and there exists a sufficient amount
of lubricating oil on the upper side of the inner surface of the
blank tube, it can be controlled to perform drawing.
[0133] Therefore, a drawn tube having no seizures can be produced
(a drawn tube having seizures will not be produced).
[0134] In the invention [4], the operation of the device can be
stopped when an amount of the lubricating oil carried into the
metal blank tube from the plug is not sufficiently secured, and the
operation of the device can be continued as it is when an amount of
the lubricating oil carried into the metal blank tube from the plug
is sufficiently secured.
[0135] Further, when it exceeds the second allowed time during a
period of time until it becomes ready to be drawn, or at a time at
which it becomes ready to be drawn, the amount of the lubricating
oil on the upper side of the inner side of the blank tube is
insufficient. Therefore, the operation of the device is stopped to
not perform drawing of the blank tube. For a blank tube in which
the second elapsed time until it becomes ready to be drawn is
within the second allowed time and there exists a sufficient amount
of lubricating oil on the upper side of the inner surface thereof,
drawing is performed. Therefore, a drawn tube having no seizures
can be produced (a drawn tube having seizures will not be
formed).
[0136] In the invention [5], the operation of the device can be
stopped when it exceeds the first allowed time during a period of
time until the plug is inserted into the blank tube or at a time at
which the plug is inserted into the blank tube and therefore an
amount of the lubricating oil carried into the metal blank tube
from the plug cannot not be sufficiently secured. When an amount of
the lubricating oil carried into the metal blank tube from the plug
is sufficiently secured, the operation of the device can be
continued as it is.
[0137] Further, for a blank tube in a state in which it took time
(it exceeded the second allowed time) until it becomes ready to be
drawn and an amount of the lubricating oil on the upper side of the
inner surface thereof has decreased, it is possible to not perform
drawing. For a blank tube in which the second elapsed time until it
becomes ready to be drawn is within the second allowed time and
there exists a sufficient amount of lubricating oil on the upper
side of the inner surface thereof, it is possible to perform
drawing. Therefore, a drawn tube having no seizures can be produced
(a drawn tube having seizures will not be formed).
[0138] In the invention [6], when it exceeds the first allowed time
during a period of time until the plug is inserted into the blank
tube or at a time at which the plug is inserted into the blank tube
and an amount of the lubricating oil carried into the metal blank
tube from the plug cannot be sufficiently secured, the operation of
the device can be stopped. When an amount of the lubricating oil
carried into the metal blank tube from the plug is sufficiently
secured, the operation of the device can be continued as it is.
[0139] Further, when it exceeds the second allowed time during a
period of time until it becomes ready to be drawn or at a time at
which it becomes ready to be drawn, the amount of the lubricating
oil on the upper side of the inner side of the blank tube is
insufficient. Therefore, the operation of the device is stopped to
not perform drawing. For a blank tube in which the second elapsed
time until it becomes ready to be drawn is within the second
allowed time and there exists a sufficient amount of lubricating
oil on the upper side of the inner surface thereof, drawing is
performed. Therefore, a drawn tube having no seizures can be
produced (a drawn tube having seizures will not be formed).
[0140] In the invention [7], an elapsed time is measured from a
time at which supplying of the lubricating oil to the surface of
the plug is stopped until the metal blank tube is set at a drawing
position between the die and the plug and becomes ready to be
drawn, it is controlled to not perform drawing of the metal blank
tube when the measured elapsed time exceeds the preset allowed
time, and drawing is performed when the measured elapsed time is
within the preset allowed time. Therefore, for a blank tube in a
state in which it took time (it exceeded the allowed time) until it
becomes ready to be drawn and the amount of the lubricating oil on
the upper side of the inner surface of the blank tube has
decreased, it is possible to not perform drawing. For a blank tube
in which the elapsed time until it becomes ready to be drawn is
within the allowed time and there exists a sufficient amount of
lubricating oil on the upper side of the inner surface of the blank
tube, drawing is performed. Therefore, it is possible to produce a
drawn tube having no seizures (a drawn tube having seizures will
not be produced).
[0141] In the invention [8], a measurement of an elapsed time is
initiated from a time at which supplying of the lubricating oil to
the surface of the plug is stopped, it is controlled to stop the
operation of the device when the measuring elapsed time exceeds the
preset allowed time during a period of time from the initiation of
the measurement until the metal blank tube is set at a drawing
position between the die and the plug and becomes ready to be
drawn, or at a time at which it becomes ready to be drawn. Drawing
is performed when the measuring elapsed time is within the preset
allowed time at a time at which the metal blank tube is set at a
drawing position between the die and the plug and becomes ready to
be drawn. Therefore, the operation of the device is stopped when
the allowed time has exceeded during a period of time until it
becomes ready to be drawn, or at a time at which it becomes ready
to be drawn. For a blank tube in which the elapsed time until it
becomes ready to be drawn is within the allowed time and there
exists a sufficient amount of lubricating oil on the upper surface
of the inner surface of the blank, drawing is performed. Therefore,
a drawn tube having no seizures can be produced (a drawn tube
having seizures will not be formed).
[0142] In the invention [9], a first elapsed time is measured from
a time at which supplying of the lubricating oil to the surface of
the plug is stopped until the plug is inserted into the metal blank
tube, and it is controlled to stop the operation of the device when
the measured first elapsed time exceeds the preset first allowed
time, and the operation of the device is continued when the
measured first elapsed time is within the first allowed time.
Therefore, the operation of the device can be stopped when the
amount of the lubricating oil carried into the metal blank tube
from the plug is not sufficiently secured, and the operation of the
device can be continued as it is when the amount of the lubricating
oil carried into the metal blank tube from the plug is sufficiently
secured.
[0143] Further, for a blank tube in a state in which it took time
(it exceeded the second allowed time) until it becomes ready to be
drawn and the amount of the lubricating oil on the upper side of
the inner surface thereof has decreased, it is possible to not
perform drawing. For a blank tube in which the second elapsed time
until it becomes ready to be drawn is within the second allowed
time and there exist a sufficient amount of the lubricating oil on
the upper side of the inner surface thereof, drawing is performed.
Therefore, a drawn tube having no seizures can be produced (a drawn
tube having seizures will not be formed).
[0144] In the invention [10], the operation of the device can be
stopped when the amount of the lubricating oil carried into the
metal blank tube from the plug is not sufficiently secured. And the
operation of the device can be continued as it is when the amount
of the lubricating oil carried into the metal blank tube from the
plug is sufficiently secured.
[0145] Further, when the measuring second elapsed time exceeds the
second allowed time during a period of time until it becomes ready
to be drawn, or at a time at which it becomes ready to be drawn,
the amount of the lubricating oil on the upper side of the inner
side of the blank tube becomes insufficient. Therefore, the
operation of the device is stopped to not perform drawing of the
blank tube. For a blank tube in which the measuring second elapsed
time is within the second allowed time and there exists a
sufficient amount of the lubricating oil on the upper side of the
inner surface thereof at a time at which the metal blank tube is
set at a drawing position between the die and the plug and becomes
ready to be drawn, drawing is performed. Therefore, a drawn tube
having no seizures can be produced (a drawn tube having seizures
will not be formed).
[0146] In the invention [11], the operation of the device can be
stopped when it exceeds the first allowed time during a period of
time until the plug is inserted into the blank tube or at a time at
which the plug is inserted into the blank tube, and the amount of
the lubricating oil carried into the metal blank tube from the plug
cannot be sufficiently secured. And the operation of the device can
be continued as it is when the amount of the lubricating oil
carried into the metal blank tube from the plug is sufficiently
secured.
[0147] Further, for a blank tube in a state in which it took time
(it exceeded the second allowed time) until it becomes ready to be
drawn and the amount of the lubricating oil on the upper side of
the inner surface thereof has decreased, it is possible to not
perform drawing. For a blank tube in which the second elapsed time
until it becomes ready to be drawn is within the second allowed
time and there exists a sufficient amount of lubricating oil on the
upper side of the inner surface thereof, drawing is performed.
Therefore a drawn tube having no seizures can be produced (a drawn
tubes having seizures will not be formed).
[0148] In the invention [12], when it exceeds the first allowed
time during a period of time until the plug is inserted into the
blank tube or at a time at which the plug is inserted into the
blank tube, the operation of the device can be stopped. When the
amount of the lubricating oil carried into the metal blank tube
from the plug is sufficiently secured, the operation of the device
can be continued as it is.
[0149] Further, when the measuring second elapsed time exceeds the
second allowed time during a period of time until it becomes ready
to be drawn or at a time at which the tube becomes ready to be
drawn, since the amount of the lubricating oil on the upper side of
the inner side of the blank tube is insufficient, drawing is not
performed. For a blank tube in which the measuring second elapsed
time is within the second allowed time and there exists a
sufficient amount of lubricating oil on the upper side of the inner
surface thereof at a time at which the metal blank tube is set at a
drawing position between the die and the plug and becomes ready to
be drawn, drawing is performed. Therefore, a drawn tube having no
seizures can be produced (a drawn tube having seizures will not be
formed).
[0150] In the invention [13], since the application step, the
insertion step, and the setting step are performed in this order,
seizures of the tube at the time of drawing can be sufficiently
prevented from being occurred, which enables a production of a high
quality drawn tube having no seizures.
[0151] In the invention [14], a metal tube is produced by measuring
an elapsed time from a time at which supplying of the lubricating
oil to the surface of the plug is stopped until the metal blank
tube is set at a drawing position between the die and the plug and
becomes ready to be drawn, controlling to not perform drawing the
metal blank tube when the measured elapsed time exceeds the preset
allowed time, and performing drawing when the measured elapsed time
is within the preset allowed time. Therefore, for a blank tube in a
state in which it took time (it exceeded the allowed time) and
becomes ready to be drawn and the mount of the lubricating oil on
the upper side of the inner surface of the blank tube has
decreased, it is possible to not perform drawing. For a blank tube
in which the elapsed time until it becomes ready to be drawn is
within the allowed time and there exists a sufficient amount of the
lubricating oil on the upper side of the inner surface of the blank
tube, drawing is performed. Therefore, a drawn tube having no
seizures can be produced (a drawn tube having seizures will not be
formed).
[0152] In the invention [15], since the application step, the
insertion step, and the setting step are performed in this order,
seizures of the tubes at the time of drawing can be sufficiently
prevented from being occurred, which enables a production of a high
quality drawn tube having no seizures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0153] FIG. 1 is a front vertical cross-sectional view showing a
portion of an embodiment of a drawing device according to the
present invention.
[0154] FIG. 2 (a) is a cross-sectional view showing a state in
which a lubricating oil is being applied to a surface of a plug,
FIG. 2 (b) a cross-sectional view showing a state in which
supplying of the lubricating oil to the surface of the plug is
stopped, and FIG. 2 (c) a cross-sectional view showing a state in
which an insertion of the plug into the metal blank tube is
initiated.
[0155] FIG. 3 (a) is a cross-sectional view showing a state in
which the insertion and the arrangement of the plug into the metal
blank tube is finished, and FIG. 3 (b) is a cross-sectional view
showing a state in which the metal blank tube is set at a drawing
position between the die and the plug, the front end of the blank
tube is chucked, and the tube has become available to be drawn.
[0156] FIG. 4 is a flow chart showing an example of a drawing
method.
[0157] FIG. 5 is a flow chart showing another example of a drawing
method.
[0158] FIG. 6 is a flow chart showing still another example of a
drawing method.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0159] FIG. 1 is a schematic view shown by a vertical cross-section
and showing a portion of an example of a drawing device 1 for
carrying out a drawing method for a metal tube according to the
present invention (schematic view showing a state in which the tube
is being drawn). The drawing method and the drawing device 1
according to this embodiment perform a drawing process by drawing a
metal blank tube 2 in a horizontal direction, but not especially
limited to such an embodiment, and can perform a drawing process by
drawing in a vertical direction, for example.
[0160] The drawing device 1 includes a die 10 for forming an outer
surface of a metal blank tube 2, a plug 11 for forming an inner
surface of the metal blank tube 2, a nozzle portion 18 for applying
a lubricating oil L, a chucking unit 21 for holding a front end
portion of the metal blank tube 2, a pulling unit 24 for pulling
the chucking unit 21, and a control unit 31 (see FIG. 1).
[0161] The die 10 is equipped with a die main body 13 fitted in a
die case 12, and the die main body 13 includes an approach portion
14 formed on an inner circumferential surface of a central die hole
and a bearing portion 15 continued from a front side of the
approach portion 14.
[0162] The plug 11 is attached to and supported by the front end of
a rod 20 made of a hollow tube. The plug 11 has, on its outer
peripheral surface, an approach portion 16 and a bearing portion 17
continued from the approach portion 16 toward the front side
thereof.
[0163] The chucking unit 21 includes a pair of chuck fingers 22 and
22 for chucking the front end portion (pointing portion) of the
metal blank tube 2 in cooperation with each other, and a chuck
finger holder 23 for holding the chuck fingers 22 and 22. During a
drawing process, the chucking unit 21 is pulled in the right
direction of the figure by the pulling unit 24, and in this way,
the drawing of the metal blank tube 2 is performed. That is, by
drawing the metal blank tube 2 in a horizontal direction with the
tube 2 inserted between the die 10 and the plug 11, the outer
surface of the tube is formed by the bearing portion 15 of the die
main body 13, and the inner surface of the tube is formed by the
bearing portion 17 of the plug 11. Thus, a drawn tube 3 is
produced.
[0164] The nozzle portion 18 is arranged at a rear upper portion of
the die 10 (see FIG. 1). A lubricating oil L is ejected from the
nozzle portion 18. The nozzle portion 18 is used for supplying
(applying) the lubricating oil L to the surface of the plug 11 and
supplying (applying) the lubricating oil L to the outer surface of
the metal blank tube 2.
[0165] The control unit 31 is configured to: measure an elapsed
time T from a time at which supplying of the lubricating oil L to
the surface of the plug 11 is stopped until the metal blank tube 2
is set at a drawing position between the die 10 and the plug 11,
the front end portion of the metal blank tube 2 is held by the
chucking unit 21 and the tube becomes ready to be drawn; control to
not perform drawing of the metal blank tube 2 when the measured
elapsed time T exceeds a preset allowed time; and control to
initiate drawing when the measured elapsed time T is within the
preset allowed time (see FIG. 4).
[0166] The preset allowed time T is not especially limited, but can
be 120 seconds, for example.
[0167] The control unit 31 is configured to control to not move the
pulling unit 24 when drawing is not performed (stop control) and
control to move the pulling unit 24 when drawing is initiated.
[0168] Next, the drawing method of a metal tube using the drawing
device 1 will be explained with reference to the flow chart of FIG.
4. In the flow charts of FIGS. 4 to 6, "step" is abbreviated as "S"
for simplification.
[0169] First, as shown in FIG. 2 (a), the plug 11 is arranged at a
lower position of the nozzle portion 18, and the supplying
(application) of the lubricating oil L to the surface of the plug
11 from the nozzle portion 18 is initiated (S01).
[0170] After applying the lubricating oil L to the surface of the
plug 11 for a predetermined time (predetermined amount), the
supplying (application) of the lubricating oil L to the surface of
the plug 11 is stopped (S02), as shown in FIG. 2(b). Simultaneously
with the stopping, a measurement of the elapsed time T is
initiated. That is, the measurement of the elapsed time T is
initiated from the time at which the supplying of the lubricating
oil L to the surface of the plug 11 is stopped. The lubricating oil
L adhered to the upper portion of the outer surface of the plug 11
is supplied to the entire circumference of the outer surface of the
plug 11 along the outer surface, and the excessive lubricating oil
L flows down as time passes.
[0171] After that, as shown in FIG. 2(c), the insertion of the plug
to which the lubricating oil L was applied into the metal blank
tube 2 is initiated, and as shown in FIG. 3(a), the plug 11 to
which the lubricating oil L was applied is inserted and arranged
inside (at a predetermined position) the metal blank tube 2
(S03).
[0172] Next, as shown in FIG. 3(b), these plug 11 and metal blank
tube 2 are inserted into the die 10 and set at a drawing position
(arranged). That is, the metal blank tube 2 is set at a drawing
position between the die 10 and the plug 11 (S04). Simultaneously
with setting (arranging) the tube at the drawing position,
supplying of the lubricating oil L to the outer surface of the
metal blank tube 2 from the nozzle portion 18 is initiated (see
FIG. 3(b)).
[0173] Next, as shown in FIG. 3(b), the front end portion (pointing
portion) of the metal blank tube 2 is chucked (sandwiched and
fastened) by a pair of chuck fingers 22 and 22 (S05). The
measurement of the elapsed time T is terminated when the blank tube
2 becomes in a drawable state by completion of sandwiching and
fastening the blank tube 2 by the chucking unit 21.
[0174] The control unit 31 determines whether or not the elapsed
time T (the elapsed time T from a time at which supplying of the
lubricating oil to the surface of the plug is stopped until the
tube becomes ready to be drawn) is within a preset allowed time
(S06).
[0175] When the measured elapsed time T exceeds the preset allowed
time (when the judgment result is NO), the drawing of the metal
blank tube 2 is not initiated (drawing is not performed) and an
alarm is sounded (S10). Next, the plug 11 is moved backwards (moved
back in a direction separating from the die 10) (S11). Thereafter,
the metal blank tube 2 set at the drawing position is pulled out
(removed) (S12) to prepare for a drawing process for the next new
metal blank tube 2.
[0176] On the other hand, when the measured elapsed time T is
within the preset allowed time (when the judgment result is YES),
drawing is initiated (S07). That is, as shown in FIG. 1, the metal
blank tube 2 is subjected to a drawing process by making the tube
pass through between the die 10 and the plug 11 to obtain a drawn
tube 3 by pulling the front end portion of the blank tube 2 by the
chucking unit 21 while applying the lubricating oil L on the outer
surface of the metal blank tube 2 from the nozzle portion 18 (S08).
Then, the plug 11 is moved backwards (moved back in a direction
separating from the die 10) (S09) to prepare for a drawing process
for the next new metal blank tube 2.
[0177] In the aforementioned drawing method, for a blank tube 2 in
a state in which the amount of the lubricating oil on the upper
side of the inner surface of the blank tube 2 has decrease since it
took time (it exceeded the allowed time) until it become ready to
be drawn, it is possible to not perform drawing (drawing operation
can be cancelled). Also, for a blank in which the elapsed time T
until it becomes ready to be drawn is within the allowed time and
there exists a sufficient amount of lubricating oil on the upper
side of the inner surface of the blank tube 2, drawing is
performed. Therefore, a drawn tube 3 having no seizures can be
produced (a drawn tube having seizures is not formed).
[0178] Further, in the aforementioned first embodiment, the control
unit 31 (control method) can be configured as follows. That is, in
the first embodiment, the control unit 31 can be configured to have
a structure (control method) as follows:
[0179] the measurement of the elapsed time is initiated from a time
at which supplying of the lubricating oil L to the surface of the
plug 11 is stopped;
[0180] it is controlled to stop the operation of the device 1 when
the measuring elapsed time T exceeds a preset allowed time during a
period of time from the initiation of the measurement until the
metal blank tube 2 is set (arranged) at a drawing position between
the die 10 and the plug 11, the front end portion of the metal
blank tube 2 is held by the chucking unit 21 and the tube becomes
ready to be drawn, or at the time at which the tube becomes ready
to be drawn; and
[0181] it is controlled to initiate drawing when the measuring
elapsed time T is within the preset allowed time at a time at which
the metal blank tube 2 is set (arranged) at a drawing position
between the die 10 and the plug 11, the front end portion of the
metal blank tube 2 is held by the chucking unit 21 and the tube
becomes ready to be drawn.
[0182] Another embodiment (second embodiment) of a drawing device 1
according to the present invention will be explained. The structure
of the drawing device 1 of this second embodiment is as shown in
FIG. 1. Although the structure of the control unit 31 (control
method) is different from the aforementioned first embodiment, the
other structures are the same as those of the first embodiment.
[0183] That is, in this second embodiment, the control unit 31 is
configured to: measure a first elapsed time T1 from a time at which
supplying of the lubricating oil L to the surface of the plug 11 is
stopped until the plug 11 is inserted into the metal blank tube 2;
control to stop the operation of the drawing device 1 when the
measured first elapsed time T1 exceeds the preset first allowed
time; and control to continue the operation of the drawing device 1
when the measured first elapsed time T1 is within the first allowed
time (see FIG. 5).
[0184] Further, the control unit 31 is configured to: measure a
second elapsed time T2 from at time at which the plug is inserted
into the metal blank tube 2 until the metal blank tube 2 is set at
a drawing position between the die 10 and the plug 11, the front
end portion of the metal blank tube 2 is held by the chucking unit
21 and the tube becomes ready to be drawn; control to not perform
drawing of the metal blank tube 2 when the measured second elapsed
time T2 exceeds a preset second allowed time; and control to
initiate drawing when the measured second elapsed time T2 is within
the preset second allowed time (see FIG. 5).
[0185] In this second embodiment, the preset first allowed time T1
is not especially limited, but can be 30 seconds, for example.
Also, the preset second allowed time T2 is not especially limited,
but can be 90 seconds, for example.
[0186] Next, a drawing method of a metal tube using the drawing
device 1 according to the second embodiment will be explained with
reference to the flow chart of FIG. 5.
[0187] First, as shown in FIG. 2(a), the plug 11 is arranged at a
lower position of the nozzle portion 18, and supplying
(application) of the lubricating oil L to the surface of the plug
11 from the nozzle portion 18 is initiated (S21).
[0188] After applying the lubricating oil L to the surface of the
plug 11 for a predetermined time (predetermined amount), as shown
in FIG. 2(b), the supplying (application) of the lubricating oil L
to the surface of the plug 11 is stopped (S22). Simultaneously with
the stopping, a measurement of the first elapsed time T1 is
initiated. That is, the measurement of the first elapsed time T1 is
initiated from a time at which supplying of the lubricating oil L
to the surface of the plug 11 is stopped. The lubricating oil L
adhered to the upper portion of the outer surface of the plug 11 is
supplied to the entire periphery of the outer surface of the plug
11 along the outer surface, and the excessive lubricating oil L
flows down as time passes.
[0189] Thereafter, as shown in FIG. 2(c), the insertion of the plug
to which the lubricating oil L was applied into the metal blank
tube 2 is initiated, and as shown in FIG. 3(a), the plug 11 to
which the lubricating oil L was applied is inserted and arranged
inside (at a predetermined position) the metal blank tube 2 (S23).
At this time, as shown in FIG. 2(c), the measurement of the first
elapsed time T1 is terminated at a time at which the plug 11 is
inserted into the metal blank tube 2, and at the same time, the
measurement of the second elapsed time T2 is initiated (see FIG.
5).
[0190] The control unit 31 determines whether or not the measured
first elapsed time T1 (the first elapsed time T from a time at
which supplying of the lubricating oil to the surface of the plug
is stopped until the plug is inserted into the metal blank tube 2)
is within a preset first allowed time (S24).
[0191] When the measured first elapsed time T1 exceeds the preset
first allowed time (when the judgment result is NO), the operation
of the drawing device 1 is stopped and an alarm is sounded
(S34).
[0192] On the other hand, when the measured first elapsed time T1
is within the preset first allowed time (when the judgment result
is YES), as shown in FIG. 3(b), the plug 11 and the metal blank
tube 2 are inserted into the die 10 and set (arranged) at the
drawing positions. That is, the metal blank tube 2 is set
(arranged) at a drawing position between the die 10 and the plug 11
(S25). Simultaneously with the setting (arranging) of the tube at
the drawing position, supplying of the lubricating oil L to the
outer surface of the metal blank tube 2 from the nozzle portion 18
is initiated (see FIG. 3(b)).
[0193] Next, as shown in FIG. 3(b), the front end portion (pointing
portion) of the metal blank tube 2 is chucked (sandwiched and
fastened) by a pair of chuck fingers 22 and 22 (S26). The
measurement of the second elapsed time T2 is terminated when the
sandwiching and fastening of the blank tube 2 by the chucking unit
21 is completed and the tube becomes in a drawable state (see FIG.
5).
[0194] The control unit 31 determines whether or not the second
elapsed time T2 (the elapsed time T2 from a time at which the plug
11 is inserted into the metal blank tube 2 until the tube becomes
ready to be drawn) is within a preset second allowed time
(S27).
[0195] When the measured second elapsed time T2 exceeds the preset
second allowed time (when the judgment result is NO), drawing of
the metal blank tube 2 is not initiated (drawing is not performed)
and an alarm is sounded (S31). Next, the plug 11 is moved backwards
(moved back in a direction separating from the die 10) (S32).
Thereafter, the metal blank tube 2 set at the drawing position is
pulled out (removed) (S33) to prepare for a drawing process for the
next new metal blank tube 2.
[0196] On the other hand, when the measured second elapsed time T2
is within the preset second allowed time (when the judgment result
is YES), drawing is initiated (S28). That is, as shown in FIG. 1, a
drawing process is performed by making the metal blank tube 2 pass
through between the die 10 and the plug 11 by pulling the front end
portion of the blank tube 2 by the chucking unit 21 while applying
the lubricating oil L on the outer surface of the metal blank tube
2 from the nozzle portion 18 (S29) to obtain a drawn tube 3 and
complete the drawing. Thereafter, the plug 11 is moved backwards
(moved back in a direction separating from the die 10) (S30) to
prepare for a drawing process for the next new metal blank tube
2.
[0197] In the aforementioned drawing method, in the judgment in
S24, when the measured first elapsed time T1 exceeds the preset
first allowed time and a sufficient amount of the lubricating oil
carried into the metal blank tube 2 from the plug 11 is not
secured, the operation of the device 1 can be stopped; and when the
measured first elapsed time T1 is within the preset first allowed
time, and a sufficient amount of the lubricating oil carried into
the metal blank tube 2 from the plug 11 is secured, the operation
of the device 1 can be continued as it is. Further, through the
judgment in S27, for a blank tube in a state in which the amount of
the lubricating oil on the upper side of the inner surface thereof
has decreased since it took time (the second elapsed time T2
exceeded the second allowed time), it can be configured to not
perform drawing. For a blank tube 2 in which the second elapsed
time T2 until it becomes ready to be drawn is within the second
allowed time and there exists a sufficient amount of lubricating
oil on the upper side of the inner surface of the blank tube 2,
drawing is performed. Therefore, a drawn tubes 3 having no seizures
can be produced (a drawn tube having seizures will not be
formed).
[0198] Further, in the aforementioned second embodiment, the
structure of the control unit 31 (control method) can be changed
into the following structure. That is, in the second embodiment, as
for the measurement of the first elapsed time T1 and the judgment
in S24, the control unit 31 can be configured to have a structure
(control method) as follows: the measurement of the first elapsed
time T1 is initiated from a time at which supplying of the
lubricating oil L to the surface of the plug 11 is stopped; it is
controlled to stop the operation of the device 1 when the measuring
first elapsed time T1 exceeds a preset first allowed time during a
period of time from the initiation of the measurement until the
plug 11 is inserted into the metal blank tube 2, or at a time at
which the plug 11 is inserted; and it is controlled to continue the
operation of the device 1 when the measuring first elapsed time T1
is within a preset first allowed time at a time at which the plug
11 is inserted into the metal blank tube 2. Further, in the second
embodiment, as for the measurement of the second elapsed time T2
and the judgment in S27, the control unit 31 can be configured to
have a structure (control method) as follows: the measurement of
the second elapsed time T2 is initiated from a time at which the
plug 11 is inserted into the metal blank tube 2; it is controlled
to stop the operation of the device 1 when the measuring second
elapsed time T2 exceeds a preset second allowed time during a
period of time from the initiation of the measurement until the
metal blank tube 2 is set (arranged) at a drawing position between
the die 10 and the plug 11, the front end portion of the metal
blank tube 2 is held by the chucking unit 21 and the tube becomes
ready to be drawn, or at the time at which the pipe becomes ready
to be drawn; and it is controlled to initiate drawing when the
measuring second elapsed time T2 is within the preset second
allowed time at a time at which the metal blank tube 2 is set
(arranged) at a drawing position between the die 10 and the plug
11, the front end portion of the metal blank tube 2 is held by the
chucking unit 21 and the pipe becomes ready to be drawn.
[0199] Still another embodiment (third embodiment) of a drawing
device 1 according to the present invention will be explained. The
structure of the drawing device 1 of this third embodiment is as
shown in FIG. 1. Although the structure of the control unit 31
(control method) is different from the aforementioned first
embodiment, the other structures are the same as those of the
aforementioned first embodiment.
[0200] That is, in this third embodiment, the control unit 31 is
configured to: measure a first elapsed time T1 from a time at which
supplying of the lubricating oil L to the surface of the plug 11 is
stopped until the plug 11 is inserted into the metal blank tube 2;
control to stop the operation of the drawing device 1 when the
measured first elapsed time T1 exceeds the preset first allowed
time; and control to continue the operation of the drawing device 1
when the measured first elapsed time T1 is within the first allowed
time (see FIG. 6).
[0201] Further, the control unit 31 is configured to: measure a
second elapsed time T from a time at which supplying of the
lubricating oil L to the surface of the plug 11 is stopped until
the metal blank tube 2 is set at a drawing position between the die
10 and the plug 11, the front end portion of the metal blank tube 2
is held by the chucking unit 21 and the tube becomes ready to be
drawn; control to not perform drawing of the metal blank tube 2
when the measured second elapsed time T exceeds the preset second
allowed time; and control to initiate drawing when the measured
second elapsed time T is within the preset second allowed time (see
FIG. 6).
[0202] In this third embodiment, the preset first allowed time T1
is not especially limited, but can be 30 seconds, for example.
Also, the preset second allowed time T is not especially limited,
but can be 90 seconds, for example.
[0203] Next, a flowchart of a drawing method of a metal tube using
the drawing device 1 according to the aforementioned third
embodiment is shown in FIG. 6. It is different from the drawing
method of a metal tube using the drawing device 1 according to the
aforementioned second embodiment (see FIG. 5) in that the
initiation of the measurement of the second elapsed time T in the
control unit 31 is set to "a time at which supplying of the
lubricating oil L to the surface of the plug 11 is stopped." The
other methods are the same as those of the aforementioned second
embodiment.
[0204] In the drawing method according to this third embodiment, in
the judgment in S24, when the measured first elapsed time T1
exceeds the preset first allowed time and a sufficient amount of
the lubricating oil carried into the metal blank tube 2 from the
plug 11 is not secured, the operation of the device 1 can be
stopped; and when the measured first elapsed time T1 is within the
preset first allowed time and a sufficient amount of the
lubricating oil carried into the metal blank tube 2 from the plug
11 is secured, the operation of the device 1 can be continued as it
is. Further, through the judgment in S27, for a blank tube in a
state in which the amount of the lubricating oil on the upper side
of the inner surface thereof has decreased since it took time (the
second elapsed time T exceeded the second allowed time), it can be
configured to not perform drawing; and for a blank tube 2 in which
the second elapsed time T until it becomes ready to be drawn is
within the second allowed time and there exists a sufficient amount
of lubricating oil on the upper side of the inner surface of the
blank tube 2, drawing is performed. Therefore, a drawn tubes 3
having no seizures can be produced (a drawn tube having seizures
will not be formed).
[0205] Further, in the aforementioned third embodiment, the
structure of the control unit 31 (control method) can be changed
into the following structure. That is, in the third embodiment, as
for the measurement of the first elapsed time T1 and the judgment
in S24, the control unit 31 can be configured to have a structure
(control method) as follows:
[0206] the measurement of the first elapsed time T1 is initiated
from a time at which supplying of the lubricating oil L to the
surface of the plug 11 is stopped;
[0207] it is controlled to stop the operation of the device 1 when
the measuring first elapsed time T1 exceeds a preset first allowed
time during a period of time from the initiation of the measurement
until the plug 11 is inserted into the metal blank tube 2, or at a
time at which the plug 11 is inserted; and
[0208] it is controlled to continue the operation of the device 1
when the measuring first elapsed time T1 is within a preset first
allowed time at a time at which the plug 11 is inserted into the
metal blank tube 2.
[0209] Further, in the third embodiment, as for the measurement of
the second elapsed time T and the judgment in S27, the control unit
31 can be configured to have a structure (control method) as
follows:
[0210] the measurement of the second elapsed time T is initiated
from a time at which supplying of lubricating oil L to a surface of
the plug 11 is stopped;
[0211] it is controlled to stop the operation of the device 1 when
the measuring second elapsed time T exceeds a preset second allowed
time during a period of time from the initiation of the measurement
until the metal blank tube 2 is set (arranged) at a drawing
position between the die 10 and the plug 11, the front end portion
of the metal blank tube 2 is held by the chucking unit 21 and the
tube becomes ready to be drawn, or at the time at which the pipe
becomes ready to be drawn; and
[0212] it is controlled to initiate drawing when the measuring
second elapsed time T is within the preset second allowed time at a
time at which the metal blank tube 2 is set (arranged) at a drawing
position between the die 10 and the plug 11, the front end portion
of the metal blank tube 2 is held by the chucking unit 21 and the
pipe becomes ready to be drawn.
[0213] Further, in the first embodiment, the initiation point of
the measurement of the elapsed time T is set to the time at which
"supplying of the lubricating oil to the surface of the plug is
stopped" (see FIG. 4), and in the second embodiment, the initiation
point of the measurement of the first elapsed time T1 is set to the
time at which "supplying of the lubricating oil to the surface of
the plug is stopped" (see FIG. 5), and furthermore, in the third
embodiment, the initiation point of the measurement of the first
elapsed time T1 and the second elapsed time T are set to the time
at which "supplying of the lubricating oil to the surface of the
plug is stopped" (see FIG. 6). However, for example, if the
supplying time (application time) of the lubricating oil L is set
to be constant, the initiation points of these measurements can be
set to "initiation of supplying of the lubricating oil to the
surface of the plug" (they are essentially the same).
[0214] Also, in the aforementioned first to third embodiments,
alarms are sounded to notify an operator when the judgment result
in S06, S24, and S27 is NO, but not especially limited to that. For
example, when the judgment result is NO, a revolving light (red,
etc) can be turned on or blinked to notify an operator.
[0215] Furthermore, in the aforementioned first to third
embodiments, when drawing is not initiated (S10, S31), an operation
to pull out (eject) the set blank tube is performed afterwards
(S11, S32). The ejecting operation of the blank tube can be
performed by hand, or performed automatically by an ejecting
device. Further, a blank tube ejected in this way can be disposed,
or reused in the aforementioned drawing method.
[0216] In the present invention, the length of the metal blank tube
2 which is an object to be drawn is not limited. Since shortage of
lubricating oil more likely occurs for longer metal blank tubes,
the present invention is preferably applied to drawing of a longer
blank tube. Specifically, significant effects can be obtained for a
blank tube 2 m or longer, especially 2.5 m or longer.
[0217] In the present invention, the material of the metal blank
tube 2 which is an object to be drawn (type of metal) is not
especially limited, but can be, for example, aluminum, iron,
copper, or alloys thereof. Since significant effects can be
obtained when drawing a longer blank tube, the present invention is
suited for a production of an aluminum tube for a photosensitive
drum substrate.
EXAMPLES
[0218] Next, specific examples of the present invention will be
explained, but the present invention is not especially limited to
these examples.
Example 1
[0219] A metal blank tube 2 was drawn using the drawing device 1
according to the first embodiment having the structure shown in
FIG. 1 (see the flowchart of FIG. 4). A billet made of an aluminum
alloy (Mn: 1.12 mass %, Si: 0.11 mass %, Fe: 0.39 mass %, Cu: 0.16
mass %, Zn: 0.01 mass %, Mg: 0.02 mass %, and the balance being
aluminum and inevitable impurities) was extruded under the
condition of an extrusion temperature of 520.degree. C. and an
extrusion rate of 5 m/min to obtain a cylindrical tube having an
outer diameter of 32 mm and a thickness of 1.5 mm, and cut into 2.2
m in length, which was used as a metal blank tube 2.
[0220] In the drawing device 1, the approach angle of the approach
portion 14 of the die 10 was 15.degree., the bearing length of the
bearing portion 15 of the die 10 was 15 mm, the approach angle of
the approach portion 16 of the plug 11 was 7.degree., and the
bearing length of the bearing portion 17 of the plug 11 was 2
mm.
[0221] Applying of a lubricating oil L ejected from the nozzle
portion 18 to the surface of the plug 11 was initiated as shown in
FIG. 2(a) (S01), and the application was stopped after applying for
10 seconds (S02) (see FIG. 2(b)). The measurement of the elapsed
time T was initiated from a time at which the application was
stopped. Next, as shown in FIG. 3(a), the plug 11 to which the
lubricating oil L was applied was inserted and arranged inside the
metal blank tube 2 (S03). Then, as shown in FIG. 3(b), the metal
blank tube 2 was set at the drawing position between the die 10 and
the plug 11 (S04). Simultaneously with the setting to the drawing
position, the application of the lubricating oil L to the outer
surface of the metal blank tube 2 from the nozzle portion 18 was
initiated. Next, as shown in FIG. 3(b), the front end portion
(pointing portion) of the metal blank tube 2 was chucked by a pair
of chuck fingers 22 and 22 (which became in a drawable state)
(S05). The measurement of the elapsed time T was terminated when
the sandwiching and fastening of the blank tube 2 by the chucking
unit 21 was completed and the tube became in a drawable state.
[0222] It was determined by the control unit 31 whether or not the
elapsed time T (the elapsed time T from a time at which supplying
of the lubricating oil to the surface of the plug is stopped until
the tube becomes ready to be drawn) was within a preset allowed
time (200 seconds)(S06). In Example 1, the elapsed time T was 60
seconds, which was within the allowed time (200 seconds), so the
judgment result was YES and therefore, drawing was initiated as it
is (S07). That is, as shown in FIG. 1, the metal blank tube 2 was
drawn by making the tube pass through between the die 10 and the
plug 11 by pulling the front end portion of the blank tube 2 by the
chucking unit 21 while applying the lubricating oil L onto the
outer surface of the metal blank tube 2 from the nozzle portion 18
to obtain a drawn tube 3, and the drawing was completed (S08). A
drawn tube 3 was obtained by performing the drawing at a drawing
rate of 30 m/min, an outer diameter reduction rate of 16%, and a
cross-sectional area reduction rate of 32%. As the lubricating oil
L, a lubricating oil named "Stroll ES150" produced by Kyoueiyuka
Co. was used.
[0223] The obtained drawn tube 3 was transferred to a transfer
conveyer from the drawing device 1 and cooled at room temperature
(around 25.degree. C.) and cut into 260 mm length.
Example 2
[0224] After performing to S06 in the same manner as in Example 1,
it was judged in S06. In Example 2, the elapsed time T was 120
seconds, which was within the allowed time (200 seconds), so the
judgment result was YES and therefore, drawing was initiated as it
is (S07). That is, a drawn tube 3 was obtained by performing the
drawing in the same manner as in Example 1.
Example 3
[0225] After performing to S06 in the same manner as in Example 1,
it was judged in S06. In Example 3, the elapsed time T was 180
seconds, which was within the allowed time (200 seconds), so the
judgment result was YES and therefore, drawing was initiated as it
is (S07). That is, a drawn tube 3 was obtained by performing the
drawing in the same manner as in Example 1.
Example 4
[0226] After performing to S06 in the same manner as in Example 1,
it was judged in S06. In Example 4, the elapsed time T was 240
seconds, which exceeded the allowed time (200 seconds), so the
judgment result was NO and therefore, drawing was not initiated
(S10). After moving the plug 11 backwards (in the direction
separating from the die 10) (S11), the metal blank tube 2 set at
the drawing position was pulled out (S12) to prepare for the
drawing of the next new metal blank tube 2.
Example 5
[0227] After performing to S06 in the same manner as in Example 1,
it was judged in S06. In Example 5, the elapsed time T was 300
seconds, which exceeded the allowed time (200 seconds), so the
judgment result was NO and therefore, drawing was not initiated
(drawing was not performed) (S10). After moving the plug 11
backwards (in the direction separating from the die 10) (S11), the
metal blank tube 2 set at the drawing position was pulled out (S12)
to prepare for the drawing process of the next new metal blank tube
2.
Comparative Example 1
[0228] After performing to S06 in the same manner as in Example 1,
it was judged in S06. In Example 4, the elapsed time T was 240
seconds, which exceeded the allowed time (200 seconds), so the
judgment result was NO. But, ignoring the judgment, drawing was
performed in the same manner as in Example 1 to obtain a drawn tube
3.
Comparative Example 2
[0229] After performing to S06 in the same manner as in Example 1,
it was judged in S06. In Example 4, the elapsed time T was 300
seconds, which exceeded the allowed time (200 seconds), so the
judgment result was NO. But, ignoring the judgment, drawing was
performed in the same manner as in Example 1 to obtain a drawn tube
3.
TABLE-US-00001 TABLE 1 Seizure resistance Elapsed Time T (sec)
evaluation Example 1 60 .largecircle. Example 2 120 .largecircle.
Example 3 180 .largecircle. Comparative Example 1 240 .DELTA.
Comparative Example 2 300 X
[0230] The existence of seizures and the states of the drawn tubes
3 of Example 1 to 3 and Comparative Examples 1 and 2 obtained in
the aforementioned manner were examined, and the seizure
resistances were evaluated based on the following decision
criterion. These evaluation results are shown in Table 1.
(Decision Criterion)
[0231] ".largecircle." . . . seizures did not occur at all in the
drawn tube ".DELTA." . . . seizures occurred in the rear half
region of the drawn tube "X" . . . seizures occurred in all regions
in the lengthwise direction of the drawn tube
[0232] As it is clear from Table 1, according to the drawing
methods of the present invention (Examples 1 to 3), drawn tubes not
having seizures could be produced. Also, according to the drawing
methods of the present invention (Examples 4 and 5), production of
drawn tubes having seizures could be prevented by not performing
drawing considering the judgment in S06 ("NO" judgment).
[0233] On the other hand, in Comparative Examples 1 and 2, obtained
drawn tubes had seizures.
[0234] The present invention claims priority to Japanese Patent
Application No. 2011-186790 filed on Aug. 30, 2011, the entire
disclosure of which is incorporated herein by reference in its
entirety.
[0235] The terms and descriptions used herein are used only for
explanatory purposes and the present invention is not limited to
them. The present invention allows various design-changes falling
within the claimed scope of the present invention unless it
deviates from the spirits of the invention.
INDUSTRIAL APPLICABILITY
[0236] The device and method for drawing a metal tube according to
the present invention are suited for a production of aluminum tubes
for use in a photosensitive drum substrate since it is possible to
make a sufficient amount of lubricating oil adhere to an inner
surface of a metal blank tube in a continuous drawing of a
plurality of blank tubes.
DESCRIPTION OF THE REFERENCE NUMERALS
[0237] 1 . . . drawing device [0238] 2 . . . metal blank tube
[0239] 3 . . . drawn tube [0240] 10 . . . die [0241] 11 . . . plug
[0242] 18 . . . nozzle portion [0243] 21 . . . chucking unit [0244]
24 . . . pulling unit [0245] 31 . . . control unit [0246] L . . .
lubricating oil
* * * * *