U.S. patent application number 13/807669 was filed with the patent office on 2015-07-02 for wire drawing machine and wire drawing method.
This patent application is currently assigned to FAE, INC.. The applicant listed for this patent is FAE, INC.. Invention is credited to Kosuke Takemoto.
Application Number | 20150183013 13/807669 |
Document ID | / |
Family ID | 49595919 |
Filed Date | 2015-07-02 |
United States Patent
Application |
20150183013 |
Kind Code |
A1 |
Takemoto; Kosuke |
July 2, 2015 |
WIRE DRAWING MACHINE AND WIRE DRAWING METHOD
Abstract
A non-slip wire drawing machine with a reduced number of dancers
is provided. The wire drawing machine comprises: a first wire
drawing die for reducing a diameter of a metal wire passing
therethrough, thereby drawing the metal wire; a back tension
control unit that controls a first back tension of the metal wire
passing through the first wire drawing die; a first capstan that
pulls the metal wire passing through the first wire drawing die at
a first front tension through the first wire drawing die in a
non-slip manner; a first front tension measuring unit that measures
the first front tension; a first capstan control unit that controls
a rotation torque of the first capstan based on the measured first
front tension; and a winding unit that winds up the drawn metal
wire.
Inventors: |
Takemoto; Kosuke; (Osaka,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FAE, INC. |
Osaka |
|
JP |
|
|
Assignee: |
FAE, INC.
Osaka
JP
|
Family ID: |
49595919 |
Appl. No.: |
13/807669 |
Filed: |
September 20, 2012 |
PCT Filed: |
September 20, 2012 |
PCT NO: |
PCT/JP2012/074083 |
371 Date: |
December 28, 2012 |
Current U.S.
Class: |
72/279 ;
72/289 |
Current CPC
Class: |
B21C 1/08 20130101; B21C
1/14 20130101; B21C 1/12 20130101 |
International
Class: |
B21C 1/08 20060101
B21C001/08; B21C 1/14 20060101 B21C001/14; B21C 1/12 20060101
B21C001/12 |
Claims
1. A wire drawing machine comprising: a first wire drawing die for
reducing a diameter of a metal wire passing therethrough, thereby
drawing the metal wire; a back tension control unit that controls a
first back tension of the metal wire passing through the first wire
drawing die; a first capstan that pulls the metal wire passing
through the first wire drawing die at a first front tension through
the first wire drawing die in a non-slip manner; a first front
tension measuring unit that measures the first front tension; a
first capstan control unit that controls a rotation torque of the
first capstan based on the measured first front tension; and a
winding unit that winds up the drawn metal wire.
2. The wire drawing machine of claim 1, further comprising a second
wire drawing die which is provided between the first capstan and
the winding unit and through which the metal wire pulled out by the
first capstan passes, so as to reduce the diameter of the metal
wire passing therethrough, thereby drawing the metal wire, wherein
the first capstan delivers the metal wire to the second wire
drawing die in a non-slip manner, and wherein the first capstan
control unit controls the rotation torque of the first capstan
based on the first front tension so that the metal wire passing
through the second wire drawing die has a second back tension of a
predetermined value.
3. The wire drawing machine of claim 2, further comprising: a
second capstan that pulls the metal wire passing through the second
wire drawing die at a second front tension through the second wire
drawing die in a non-slip manner; a third wire drawing die which is
provided between the second capstan and the winding unit and
through which the metal wire pulled out by the second capstan
passes, so as to reduce the diameter of the metal wire passing
therethrough, thereby drawing the metal wire; a second front
tension measuring unit that measures the second front tension; and
a second capstan control unit that controls a rotation torque of
the second capstan based on the measured second front tension,
wherein the second capstan control unit controls the rotation
torque of the second capstan based on the second front tension so
that the metal wire passing through the third wire drawing die has
a third back tension of a predetermined value.
4. The wire drawing machine of claim 1, further comprising an
unwinding unit that delivers the metal wire to the first wire
drawing die, wherein the back tension control unit is a dancer that
controls the first back tension of the metal wire between the
unwinding unit and the first wire drawing die.
5. A wire drawing machine comprising: a first wire drawing die for
reducing a diameter of a metal wire passing therethrough, thereby
drawing the metal wire; a back tension control unit that controls a
first back tension of the metal wire passing through the first wire
drawing die; a first capstan that pulls the metal wire passing
through the first wire drawing die in a non-slip manner through the
first wire drawing die; a first capstan control unit that controls
a rotation torque of the first capstan so as to pull the metal wire
through the first wire drawing die; and a winding unit that winds
up the drawn metal wire, wherein the first capstan control unit
stores, in advance, a first front tension of the metal wire
obtained when pulling the metal wire through the first wire drawing
die by rotating the first capstan at a controlled speed, and
wherein the first capstan control unit controls the rotation torque
of the first capstan based on the first front tension so as to pull
the metal wire through the first wire drawing die.
6. The wire drawing machine of claim 5, wherein the first capstan
control unit stores, as the first front tension, an average torque
of the first capstan obtained when pulling the metal wire through
the first wire drawing die by rotating the first capstan at a
controlled speed for a predetermined period of time.
7. The wire drawing machine of claim 5, further comprising: a
second wire drawing die which is provided between the first capstan
and the winding unit and through which the metal wire pulled out by
the first capstan passes, so as to reduce the diameter of the metal
wire passing therethrough, thereby drawing the metal wire; and a
back tension measuring unit that measures a second back tension of
the metal wire passing through the second wire drawing die, wherein
the first capstan delivers the metal wire to the second wire
drawing die in a non-slip manner, and wherein the first capstan
control unit controls the rotation torque of the first capstan so
that the measured second back tension becomes a predetermined
value.
8. A wire drawing method for drawing a metal wire by causing the
metal wire to pass through a wire drawing die so as to reduce a
diameter of the metal wire, the method comprising the steps of:
controlling a back tension of the metal wire passing through the
wire drawing die; pulling the metal wire passing through the wire
drawing die at a predetermined front tension through the wire
drawing die in a non-slip manner using a capstan; measuring the
front tension; and controlling a rotation torque of the capstan
based on the measured front tension.
9. A wire drawing method for drawing a metal wire by causing the
metal wire to pass through a wire drawing die so as to reduce a
diameter of the metal wire, the method comprising: a step of
controlling a back tension of the metal wire passing through the
wire drawing die; a step of pulling the metal wire passing through
the wire drawing die in a non-slip manner through the wire drawing
die using a capstan; and a controlling step of controlling a
rotation torque of the capstan, wherein the controlling step
comprises the steps of: storing, in advance, a front tension of the
metal wire obtained when pulling the metal wire through the wire
drawing die by rotating the capstan at a controlled speed; and
controlling the rotation torque of the capstan based on the front
tension so as to pull the metal wire through the wire drawing die.
Description
TECHNICAL FIELD
[0001] The present invention relates to a wire drawing machine and
wire drawing method for drawing metal wires. The invention
particularly relates to a wire drawing machine and wire drawing
method for drawing metal wires in a non-slip manner.
BACKGROUND ART
[0002] One example of a conventional wire drawing machine is
described in JP2003-053418 A (Patent Document 1), and it is called
a slip-type wire drawing machine. Such conventional slip-type wire
drawing machine sets the rotation speed of a capstan higher than
the speed of the metal wire so as to cause a slip between the
capstan and the metal wire and, using the capstan, the metal wire
is pulled through a wire drawing die, thereby drawing the metal
wire.
[0003] Prior Art References
[0004] Patent Documents
[0005] Patent Document 1: JP2003-053418 A
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
[0006] Such conventional slip-type wire drawing machine needs to
strictly control the rate of slip; however, controlling the slip
rate is difficult, particularly when drawing fine-diameter metal
wires, and this is a problem.
Means for Solving the Problem
[0007] In order to solve the above problem, according to a first
aspect of the invention, a wire drawing machine is provided which
comprises: a first wire drawing die for reducing a diameter of a
metal wire passing therethrough, thereby drawing the metal wire; a
back tension control unit that controls a first back tension of the
metal wire passing through the first wire drawing die; a first
capstan that pulls the metal wire passing through the first wire
drawing die at a first front tension through the first wire drawing
die in a non-slip manner; a first front tension measuring unit that
measures the first front tension; a first capstan control unit that
controls a rotation torque of the first capstan based on the
measured first front tension; and a winding unit that winds up the
drawn metal wire.
[0008] The above wire drawing machine may further comprise a second
wire drawing die which is provided between the first capstan and
the winding unit and through which the metal wire pulled out by the
first capstan passes, so as to reduce the diameter of the metal
wire passing therethrough, thereby drawing the metal wire. The
first capstan may deliver the metal wire to the second wire drawing
die in a non-slip manner, and the first capstan control unit may
control the rotation torque of the first capstan based on the first
front tension so that the metal wire passing through the second
wire drawing die has a second back tension of a predetermined
value.
[0009] The above wire drawing machine may further comprise: a
second capstan that pulls the metal wire passing through the second
wire drawing die at a second front tension through the second wire
drawing die in a non-slip manner; a third wire drawing die which is
provided between the second capstan and the winding unit and
through which the metal wire pulled out by the second capstan
passes, so as to reduce the diameter of the metal wire passing
therethrough, thereby drawing the metal wire; a second front
tension measuring unit that measures the second front tension; and
a second capstan control unit that controls a rotation torque of
the second capstan based on the measured second front tension, and
the second capstan control unit may control the rotation torque of
the second capstan based on the second front tension so that the
metal wire passing through the third wire drawing die has a third
back tension of a predetermined value.
[0010] The above wire drawing machine may further comprise an
unwinding unit that delivers the metal wire to the first wire
drawing die, and the back tension control unit may be a dancer that
controls the first back tension of the metal wire between the
unwinding unit and the first wire drawing die.
[0011] According to a second aspect of the invention, a wire
drawing machine is provided which comprises: a first wire drawing
die for reducing a diameter of a metal wire passing therethrough,
thereby drawing the metal wire; a back tension control unit that
controls a first back tension of the metal wire passing through the
first wire drawing die; a first capstan that pulls the metal wire
passing through the first wire drawing die in a non-slip manner
through the first wire drawing die; a first capstan control unit
that controls a rotation torque of the first capstan so as to pull
the metal wire through the first wire drawing die; and a winding
unit that winds up the drawn metal wire, wherein the first capstan
control unit stores, in advance, a first front tension of the metal
wire obtained when pulling the metal wire through the first wire
drawing die by rotating the first capstan at a controlled speed,
and wherein the first capstan control unit controls the rotation
torque of the first capstan based on the first front tension so as
to pull the metal wire through the first wire drawing die.
[0012] In the above wire drawing machine, the first capstan control
unit may store, as the first front tension, an average torque of
the first capstan obtained when pulling the metal wire through the
first wire drawing die by rotating the first capstan at a
controlled speed for a predetermined period of time.
[0013] The above wire drawing machine may further comprise: a
second wire drawing die which is provided between the first capstan
and the winding unit and through which the metal wire pulled out by
the first capstan passes, so as to reduce the diameter of the metal
wire passing therethrough, thereby drawing the metal wire; and a
back tension measuring unit that measures a second back tension of
the metal wire passing through the second wire drawing die. The
first capstan may deliver the metal wire to the second wire drawing
die in a non-slip manner, and the first capstan control unit may
control the rotation torque of the first capstan so that the
measured second back tension becomes a predetermined value.
[0014] According to a third aspect of the invention, a wire drawing
method for drawing a metal wire by causing the metal wire to pass
through a wire drawing die so as to reduce a diameter of the metal
wire is provided, the method comprising the steps of: controlling a
back tension of the metal wire passing through the wire drawing
die; pulling the metal wire passing through the wire drawing die at
a predetermined front tension through the wire drawing die in a
non-slip manner using a capstan; measuring the front tension; and
controlling a rotation torque of the capstan based on the measured
front tension.
[0015] According to a fourth aspect of the invention, a wire
drawing method for drawing a metal wire by causing the metal wire
to pass through a wire drawing die so as to reduce a diameter of
the metal wire is provided, the method comprising: a step of
controlling a back tension of the metal wire passing through the
wire drawing die; a step of pulling the metal wire passing through
the wire drawing die in a non-slip manner through the wire drawing
die using a capstan; and a controlling step of controlling a
rotation torque of the capstan, and the controlling step comprises
the steps of: storing, in advance, a front tension of the metal
wire obtained when pulling the metal wire through the wire drawing
die by rotating the capstan at a controlled speed; and controlling
the rotation torque of the capstan based on the front tension so as
to pull the metal wire through the wire drawing die.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a schematic view showing a configuration of a wire
drawing machine 100 according to an embodiment of the
invention.
[0017] FIG. 2 is a block diagram illustrating a configuration of a
control unit 200 that controls the wire drawing machine 100.
MODE FOR CARRYING OUT THE INVENTION
[0018] Hereinafter, with reference to the attached drawings, the
invention will be described through embodiments thereof. However,
the below-described embodiments do not limit the invention defined
in the claims and all combinations of features described in the
embodiments are not necessarily indispensable for the solution
according to the invention.
[0019] Configuration of Wire Drawing Machine 100
[0020] FIG. 1 is a schematic view showing a configuration of a wire
drawing machine 100 according to an embodiment of the invention.
FIG. 2 is a block diagram illustrating a configuration of a control
unit 200 that controls the wire drawing machine 100 in the above
embodiment.
[0021] In the present embodiment, the wire drawing machine 100 is
configured so as to include a housing 12, an unwinding unit 20,
wire drawing units 40 and 90, a winding unit 60 and a control unit
200 that controls each unit. In the wire drawing machine 100, the
unwinding unit 20, the wire drawing units 40 and 90 and the winding
unit 60 are arranged in this order along the route through which a
metal wire 10 is delivered out, drawn and wound (hereinafter
referred to as the "passage"), from upstream to downstream (from
left to right in FIG. 1). The wire drawing machine 100 draws the
metal wire delivered from the unwinding unit 20 sequentially at the
respective wire drawing units 40 and 90 by reducing the diameter
thereof, and winds up the drawn metal wire 10 at the winding unit
60.
[0022] The control unit 200 controls the operation of the wire
drawing machine 100. The control unit 200 is configured so as to
have a system controller 110, an unwinding unit controller 120, a
wire drawing unit controller 140 and a winding unit controller 160.
The system controller 110 is connected to the unwinding unit
controller 120, the wire drawing unit controller 140 and the
winding unit controller 160, and performs overall control of each
unit controller.
[0023] The unwinding unit controller 120, the wire drawing unit
controller 140 and the winding unit controller 160 are connected to
various components provided in the unwinding unit 20, the wire
drawing units 40 and 90 and the winding unit 60, respectively, and
control the respective units. Although only one wire drawing unit
controller 140 is shown in FIG. 2, a wire drawing unit controller
140 is provided for each of the n stages of wire drawing units 40-1
to 40-n (n being a positive integer) and the wire drawing unit
90.
[0024] The system controller 110, and the unwinding unit controller
120, the wire drawing unit controller 140 and the winding unit
controller 160 provided in the control unit 200 control the
unwinding unit 20, the wire drawing unit 40 and the winding unit 60
as stated above, so as to deliver the metal wire 10 from the
unwinding unit 20, draw it by causing it to pass through the
respective wire drawing units 40-1 to 40-n and 90, and wind it up
at the winding unit 60.
[0025] Each structure in the wire drawing machine 100 will be
described below, referring to FIGS. 1 and 2. In the present
embodiment, as illustrated in FIG. 1, n stages of wire drawing
units 40 and the wire drawing unit 90 are serially arranged between
the unwinding unit 20 and the winding unit 60 along the route
through which the metal wire 10 is delivered, so as to sequentially
draw the metal wire 10. In the below description, the wire drawing
units 40 are respectively referred to as wire drawing units 40-1 to
40-n along the direction extending from the unwinding unit 20
toward the winding unit 60.
[0026] Unwinding Unit 20
[0027] The unwinding unit 20 is configured so as to have an
unwinding bobbin 22, guide rollers 24, 26, 28 and 30, and a dancer
section 32. In the unwinding unit 20, the metal wire 10 is provided
so as to run across the unwinding bobbin 22, the guide roller 24,
the guide roller 26, a dancer roller 34, the guide roller 26 and
the guide roller 28, in this order, with a predetermined tension
being applied thereto (hereinafter, the metal wire provided as such
will be described as being "provided in a tensioned state").
[0028] The unwinding bobbin 22 is rotatably mounted in the housing
12 of the wire drawing machine 100. The unwinding bobbin 22 is
connected to an unwinding motor 122 and rotates when driven by the
motor. With that rotation, the metal wire 10 wound around the
unwinding bobbin 22 is pulled out and delivered to the passage. In
the present embodiment, the unwinding bobbin 22 is driven by the
unwinding motor 122 at a controlled speed. That is, the unwinding
unit controller 120 controls the drive of the unwinding motor 122
so that the unwinding bobbin 22 rotates at a predetermined
speed.
[0029] The guide rollers 24, 26, 28 and 30 are rotatably mounted in
the housing 12 of the wire drawing machine 100. The metal wire 10
is wound around each of the guide rollers 24, 26, 28 and 30 a
predetermined number of times so as to allow the metal wire 10 to
be delivered in a non-slip manner. The guide rollers 24, 26, 28 and
30 rotate due to tension applied to the metal wire 10 by the wire
drawing unit 40, so that the metal wire 10 delivered from the
unwinding bobbin 22 is sequentially delivered in a non-slip manner
along the passage.
[0030] The dancer section 32 is configured so as to include the
dancer roller 34, a dancer arm 36 and a torque motor 38, and
applies a desired tension to the metal wire 10 delivered from the
unwinding bobbin 22.
[0031] The dancer roller 34 is rotatably supported at one end of
the dancer arm 36 having a rod shape. The metal wire 10 is provided
in a tensioned state across the guide roller 24, the guide roller
26, the dancer roller 34, the guide roller 26 and the guide roller
28 in this order and a predetermined tension is applied to the
metal wire 10 by the dancer roller 34 in a downward direction in
FIG. 1.
[0032] The dancer arm 36 is arranged approximately horizontally in
FIG. 1, i.e. in a direction approximately perpendicular to the
direction in which tension is applied to the metal wire 10 by the
dancer roller 34. This horizontal arrangement is regarded as a
reference position for the dancer arm 36. The other end of the
dancer arm 36 is supported so as to be fixed to a drive shaft of
the torque motor 38 and the drive shaft of the torque motor 38 acts
as the pivot point of the dancer arm 36.
[0033] A potentiometer 138 (FIG. 2) is provided at the drive shaft
of the torque motor 38 and it detects a pivot angle of the dancer
arm 36. The potentiometer 138 is connected to the unwinding unit
controller 120 and provides the pivot angle detected by the
potentiometer 138 to the wire drawing unit controller 120. It
should be noted that, although the potentiometer 138 detects a
pivot angle of the dancer arm 36 in the present embodiment, the
potentiometer 138 may detect a position or displacement of the
dancer roller 34, for example, a position or displacement of the
dancer roller 34 in a direction in which tension is applied to the
metal wire 10 by the dancer roller 34. In that case, tension may be
applied to the metal wire 10 by vertically moving the dancer roller
34 (linearly moving it in a direction of applying tension to the
metal wire), instead of rotating the dancer roller 34.
[0034] The torque motor 38 applies a predetermined tension to the
metal wire 10 through the dancer arm 36 and the dancer roller 34.
That is, the torque motor 38 transmits its rotation torque to the
metal wire 10 through the dancer arm 36 and the dancer roller 34,
thereby applying tension to the metal wire 10. The torque motor 38
is connected to the unwinding unit controller 120 and generates a
predetermined rotation torque based on the commands (torque
commands) from the unwinding unit controller 120.
[0035] By transmitting the predetermined torque generated by the
torque motor 38 to the metal wire 10 through the dancer arm 36 and
the dancer roller 34 with the above configuration, the dancer
section 32 applies a particular set tension to the metal wire 10.
In other words, the tension applied to the metal wire 10 delivered
from the unwinding unit 20 is determined according to the rotation
torque of the torque motor 38.
[0036] As described above, in the unwinding unit 20 of the present
embodiment, the dancer section 32 applies a predetermined tension
to the metal wire 10 delivered from the unwinding bobbin 22 at a
constant speed and this allows the metal wire 10 to be delivered to
the wire drawing unit 40-1 with a desired tension being
applied.
[0037] Wire Drawing Unit 40
[0038] In the present embodiment, the wire drawing machine 100 is
configured so as to have n stages of wire drawing units 40-1 to
40-n and wire drawing unit 90 as the last stage between the
unwinding unit 20 and the winding unit 60. The unwinding unit 20,
the wire drawing units 40-1 to 40-n and 90, and the winding unit 60
are provided so as to be connected therebetween. The metal wire 20
delivered from the unwinding unit 20 sequentially passes through
the wire drawing units 40-1, 40-2, . . . 40-n and 90 in this order
and is thereby drawn. The drawn metal wire 10 in the wire drawing
unit 90 is then delivered to the winding unit 60. Since the wire
drawing units 40-1 to 40-n have the same configuration in the
present embodiment, the wire drawing units 40-1 to 40-n will
hereinafter be collectively referred to as a "wire drawing unit 40"
unless the wire drawing units 40-1 to 40-n are individually
specified. Further, each of the structures included in the wire
drawing units 40-1 to 40-n will also be referred to
collectively.
[0039] The wire drawing unit 40 is configured so as to have a wire
drawing die 42, guide rollers 44 and 46, and a drive capstan 50. In
the wire drawing unit 40, the metal wire 10 is provided in a
tensioned state across the guide roller 44, the wire drawing die
42, the guide roller 46 and the drive capstan 50.
[0040] The wire drawing die 42 is disposed between the guide roller
44 and the guide roller 46. The wire drawing die 42 has a die hole
extending along the direction in which the metal wire 10 is
provided in a tensioned state. When the metal wire 10 passes and is
pulled through the die hole, the diameter of the metal wire 10 is
reduced and the metal wire 10 is accordingly drawn. Here, the
reduction rate of the diameter (the reduction rate of the cross
section) of the metal wire 10 is determined according to the
diameter of the die hole provided in the wire drawing die 42, and
the metal wire 10 is drawn according to the reduction rate. In each
stage of the wire drawing units 40-1 to 40-n, the die hole diameter
of the wire drawing die 42 is selected as appropriate so that the
metal wire 10 drawn at the wire drawing unit 40-n, as the last
stage, will have a desired wire diameter.
[0041] In the present embodiment, the wire drawing units 40-1 to
40-n gradually reduce the diameter of the metal wire 10 that passes
therethrough. Accordingly, the die hole formed in the wire drawing
die 42-n has a smaller diameter than that of the die hole formed in
the wire drawing die 42-1. Further, the die hole formed in the wire
drawing die 42-2 has a smaller diameter than that of the die hole
formed in the wire drawing die 42-1.
[0042] In the present embodiment, the wire drawing die 42 is stored
in a die holder fixed to the housing 12. The wire drawing machine
100 may have means for measuring, when the metal wire 10 is pulled
and drawn through the wire drawing die 42, a force of such drawing.
Such means may be, for example, means for detecting a force with
which the wire drawing die 42 presses the die holder, which thereby
measures the drawing force, and may alternatively be means for
detecting a distortion of the die holder fixed to the housing 12,
which thereby measures the drawing force.
[0043] Here, if the metal wire 10 and/or the wire drawing die 42
are immersed with lubricating oil, vibration, etc., of the metal
wire 10 passing through the wire drawing die 42 can be prevented,
resulting in improved stability. Accordingly, an oil tank for
immersing the metal wire 10 and/or the wire drawing die 42 with
lubricating oil may be provided. For example, an oil tank may be
arranged between the wire drawing die 42 and the guide roller 44
and the metal wire 10 may be configured so as to pass through the
oil tank. In that case, it is preferable to provide means for
supplying lubricating oil to the oil tank such that the lubricating
oil flows over the oil tank during the wire drawing operation.
Alternatively, an oil tank may be arranged so as to contain the
wire drawing die 42 therein and the metal wire 10 may be configured
so as to pass through the oil tank vertically or horizontally. It
should be noted, however, that a seal is needed at the portion
through which the wire extends.
[0044] Immersing the metal wire 10 and/or the wire drawing die 42
with lubricating oil provides the following advantages. An optimum
lubricating oil can be used for the wire drawing performed at the
wire drawing die 42 in each wire drawing unit 40. The composition
of the lubricating oil greatly affects the wearing of the wire
drawing die 42, and the above configuration enables a lubricating
oil having a composition specialized for wire drawing to be stably
supplied. Furthermore, a circulation and cleaning system for the
lubricating oil, which would be necessary to reduce the effects of
contamination in the oil caused by abrasion between the metal wire
10 and the drive capstan 50, can be simplified and this leads to
reduced manufacturing costs.
[0045] The guide rollers 44 and 46 are rotatably mounted in the
housing 12 of the wire drawing machine 100. The guide rollers 44
and 46 respectively have distortion gauges 152 and 156 and encoders
154 and 158 (see FIG. 2) at their respective shafts.
[0046] The distortion gauges 152 and 156 detect distortion of the
guide rollers 44 and 46, respectively, so as to detect the tension
of the metal wire 10. The metal wire 10 provided in the wire
drawing machine 100 in a tensioned state has a certain tension at
each location, and the distortion gauge 152 detects distortion of
the guide roller 44, thereby detecting a tension of the metal wire
10 before passing through the wire drawing die 42 (hereinafter
referred to as a "front tension"). Meanwhile, the distortion gauge
156 detects distortion of the guide roller 46, thereby detecting a
tension of the metal wire 10 after passing through the wire drawing
die 42 (hereinafter referred to as a "back tension"). More
specifically, the distortion gauge 152 (156) obtains a tension of
the metal wire 10 in its delivery direction when the metal wire 10
enters the guide roller 44 (46) and also obtains a tension of the
metal wire 10 in its delivery direction when the metal wire 10
exits the guide roller 44 (46), and detects the resultant force of
the obtained tensions as such distortion.
[0047] The encoders 154 and 158 detect the speed of rotation of the
guide rollers 44 and 46, respectively, thereby detecting the speed
at which the metal wire 10 is delivered. Specifically, the encoder
154 detects the speed of rotation of the guide roller 44, thereby
detecting the speed at which the metal wire 10 is delivered in
front of the wire drawing die 42. Meanwhile, the encoder 158
detects the speed of rotation of the guide roller 46, thereby
detecting the speed at which the metal wire 10 is delivered behind
the wire drawing die 42.
[0048] The drive capstan 50 is rotatably mounted in the housing 12
of the wire drawing machine 100. A drive motor 150 (see FIG. 2) is
connected to the drive capstan 50 and the drive capstan 50 rotates
at a predetermined torque based on the commands from the wire
drawing unit controller 140. With the rotation torque, the drive
capstan 50 pulls the metal wire 10 through the wire drawing die 42
and delivers the pulled metal wire 10 to the next stage wire
drawing unit 40 or to the wire drawing unit 90.
[0049] The outer surface of the drive capstan 50 is thermal-sprayed
so as to increase the hardness of the surface and enhance
durability and also to prevent a slip from occurring between the
surface (surface in contact with the metal wire 10) of the drive
capstan 50 and the metal wire 10. The outer surface of the drive
capstan 50 may alternatively be coated with an elastic body having
a large coefficient of friction (e.g., resins such as urethane and
rubber). Such surface-treated drive capstan 50 allows the metal
wire 10 to be pulled through the wire drawing die 42 in a non-slip
manner and to be delivered to the next stage.
[0050] Wire Drawing Unit 90
[0051] The wire drawing unit 90 is configured so as to have a wire
drawing die 92, guide rollers 94 and 96, and a drive capstan 98. In
the wire drawing unit 90, the metal wire 10 is provided in a
tensioned state across the guide roller 94, the wire drawing die
92, the guide roller 96 and the drive capstan 98.
[0052] Here, the guide rollers 94 and 96 have configurations
approximately the same as or similar to those of the guide rollers
44 and 46 in the wire drawing unit 40. Further, the drive capstan
98 has a configuration approximately the same as or similar to that
of the drive capstan 50 in the wire drawing unit 40, except that
the speed thereof is controlled by the wire drawing unit controller
140.
[0053] The wire drawing die 92 has a configuration approximately
the same as or similar to the configuration of the wire drawing die
42 in the wire drawing unit 40, except that it has a function of
properly adjusting (adding or reducing) the stress and distortion
in the metal wire 10. More specifically, the wire drawing die 92 is
configured so as to be able to freely adjust the angle of the
central axis of the die hole relative to the direction in which the
metal wire 10 is pulled therethrough. The wire drawing die 92 is
also configured so as to be able to freely adjust the position of
the die hole in a direction approximately perpendicular to the
direction in which the metal wire 10 is pulled therethrough. With
this configuration, the metal wire 10 can be made in a straight
line or curled as required. Further, since the axial direction of
the die hole can be adjusted according to the direction of drawing
the metal wire 10, uneven wearing of the die can be suppressed.
[0054] Winding Unit 60
[0055] The winding unit 60 is configured so as to have guide
rollers 66, 68 and 70, a dancer section 72 and a winding bobbin 80.
In the winding unit 60, the metal wire 10 is provided in a
tensioned state across the guide roller 66, a dancer roller 74, the
guide roller 66, the guide roller 68, the guide roller 70 and the
winding bobbin 80, in this order.
[0056] The guide rollers 66, 68 and 70 are rotatably mounted in the
housing 12 of the wire drawing machine 100. The metal wire 10 is
wound around each of the guide rollers 66, 68 and 70 a
predetermined number of times so as to allow the metal wire 10 to
be delivered in a non-slip manner. The guide rollers 66, 68 and 70
rotate due to tension applied to the metal wire 10 by the rotation
of the winding bobbin 80, so that the drawn metal wire 10 in the
wire drawing unit 90 is sequentially delivered in a non-slip manner
along the passage.
[0057] The dancer section 72 is configured so as to include the
dancer roller 74, a dancer arm 76 and a torque motor 78, and
applies a desired tension to the drawn metal wire 10 in the wire
drawing unit 90.
[0058] The dancer roller 74 is rotatably supported at one end of
the rod-shaped dancer arm 76. The metal wire 10 is provided in a
tensioned state across the guide roller 66, the dancer roller 74,
the guide roller 66, the guide roller 68 and the guide roller 70 in
this order and a predetermined tension is applied to the metal wire
10 by the dancer roller 74 in a downward direction in FIG. 1.
[0059] The dancer arm 76 is arranged approximately horizontally in
FIG. 1, i.e., in a direction approximately perpendicular to the
direction in which tension is applied to the metal wire 10 by the
dancer roller 74. This horizontal arrangement is regarded as a
reference position for the dancer arm 76. The other end of the
dancer arm 76 is supported so as to be fixed to a drive shaft of
the torque motor 78 and the drive shaft of the torque motor 78 acts
as the pivot point of the dancer arm 76.
[0060] A potentiometer 178 (FIG. 2) is provided at the drive shaft
of the torque motor 78 and it detects a pivot angle of the dancer
arm 76. The potentiometer 178 is connected to the winding unit
controller 160 and provides the pivot angle detected by the
potentiometer 178 to the winding unit controller 160.
[0061] The torque motor 78 applies a predetermined tension to the
metal wire 10 through the dancer arm 76 and the dancer roller 74.
That is, the torque motor 78 transmits its rotation torque to the
metal wire 10 through the dancer arm 76 and the dancer roller 74,
thereby applying tension to the metal wire 10. The torque motor 78
is connected to the winding unit controller 160 and generates a
predetermined rotation torque based on the commands (torque
commands) from the winding unit controller 160.
[0062] The winding bobbin 80 is rotatably mounted in the housing 12
of the wire drawing machine 100. The winding bobbin 80 is connected
to a winding motor 180 and rotates when driven by the motor. With
that rotation, the drawn metal wire 10 in the wire drawing unit 90
is wound around the winding bobbin 80. In the present embodiment,
the winding bobbin 80 is driven by the winding motor 180 at a
controlled speed. That is, the winding unit controller 160 controls
the drive of the winding motor 180 so that the winding bobbin 80
rotates at a predetermined speed. More specifically, the winding
unit controller 160 controls the rotation speed of the winding
motor 180 based on the rotation speed of the drive capstan 98 and
the pivot angle of the dancer arm 76.
[0063] As described above, in the winding unit 60 according to the
present embodiment, while the dancer section 72 applies a
predetermined tension to the metal wire 10 delivered from the wire
drawing unit 90, the winding bobbin 80 winds up the metal wire 10
at a constant speed.
[0064] Wire Drawing Operation of Wire Drawing Apparatus 100
[0065] Next, the operation of the wire drawing machine 100 having
the above-described configuration so as to draw the metal wire 10
will be described with reference to FIGS. 1 and 2. In the below
examples, BTi and FTi respectively represent the back tension and
front tension of the metal wire 10 to be drawn by the wire drawing
die 42 of the i-th stage wire drawing unit 40 from among the n
stages of the wire drawing units 40, and CTi represents the
rotation torque of the drive capstan 50 of the i-th stage wire
drawing unit 40 (with i being a positive integer equal to or
smaller than n).
FIRST EXAMPLE
[0066] In the first example, the metal wire 10 is drawn by
controlling the rotation torque of the drive capstan 50 based on
the front tension of the metal wire 10 in each wire drawing unit
40. More specifically, after providing the metal wire 10 in a
tensioned state across each structure in the unwinding unit 20, the
wire drawing units 40 and the winding unit 60, the metal wire 10 is
drawn by controlling each structure as set out below.
[0067] Operation of Unwinding Unit 20
[0068] First, the unwinding unit 20 causes the metal wire 10 to be
delivered out from the unwinding unit 20 at an approximately
constant speed. Specifically, the unwinding unit controller 120
controls the speed of rotation of the unwinding motor 122 so that
the speed at which the metal wire 10 is delivered out from the
unwinding unit 20 (hereinafter a speed at which the metal wire 10
is delivered at a particular point of the passage will be referred
to as a "wire speed") is maintained at an approximately constant
value according to the speed at which the metal wire 10 is to be
delivered out from the drive capstan 98.
[0069] In the present embodiment, the unwinding unit controller 120
controls the speed of rotation of the unwinding motor 122 by using
the wire speed of the metal wire 10 at the guide roller 44 as a
feed-forward signal and the pivot angle of the dancer arm 36 as a
feedback signal. More specifically, the speed at which the metal
wire 10 is delivered out from the unwinding unit 20, namely, the
wire speed of the metal wire 10 passing through the guide roller
44, is detected by the encoder 154 provided at the guide roller 44
and fed to the wire drawing unit controller 140. Then, the
unwinding unit controller 120 provides a speed signal indicative of
the detected wire speed to the unwinding motor 122 as a
feed-forward signal, thereby controlling the rotation of the
unwinding motor 122.
[0070] Meanwhile, when the dancer arm 36 pivots and a predetermined
tension is accordingly applied to the metal wire 10 delivered from
the unwinding bobbin 22, a certain difference is created between
the wire speed of the metal wire 10 delivered from the unwinding
bobbin 22 and the wire speed of the metal wire 10 passing through
the guide roller 44. The unwinding unit controller 120 generates a
feedback signal based on such pivot angle detected by the
potentiometer 138 and controls the rotation of the unwinding motor
122 so as to correct a deviation in wire speed due to the above
difference, thereby maintaining the wire speed of the metal wire 10
delivered out from the unwinding unit 20 at an approximately
constant value.
[0071] To be more specific, the unwinding unit controller 120
calculates a pivot angle deviation between such pivot angle of the
dancer arm 36 detected by the potentiometer 138 and the pivot angle
of the dancer arm 36 at the reference position. Then, the unwinding
unit controller 120 determines the rotation speed of the unwinding
motor 122 so as to approximate the calculated pivot angle deviation
to zero, and provides a rotation speed command to the unwinding
motor 122 based on such determination. Using the pivot angle
deviation as a feedback signal, the unwinding unit controller 120
controls the rotation speed of the unwinding motor 122 through P
control, PI control, PID control, etc.
[0072] In order to deliver the metal wire 10 wound around the
unwinding bobbin 22 at a constant speed, it is necessary to control
the speed of rotation of the unwinding bobbin 22 according to the
winding diameter of the metal wire 10 wound around the unwinding
bobbin 22, and, in this respect, with the above-stated operation,
the unwinding unit 20 maintains the wire speed of the metal wire 10
delivered from the unwinding unit 20 at an approximately constant
value and, at the same time, the unwinding unit 22 applies a
predetermined tension so that the metal wire 10 has a tension set
in advance. The tension acts as a back tension BT1 of the metal
wire 10 passing through the wire drawing die 42-1. For example, the
unwinding unit controller 120 controls the unwinding unit 20 and
applies a predetermined tension to the metal wire 10 so that BT1 is
about 10% of the yield stress of the metal wire 10 wound around the
unwinding bobbin 22.
[0073] Although the unwinding unit controller 120 in the present
embodiment controls the speed of rotation of the unwinding motor
122 so as to maintain the wire speed of the metal wire 10 at an
approximately constant value while controlling the pivot angle of
the dancer arm 36 so as to apply a predetermined tension to the
metal wire 10, the tension and/or the wire speed of the metal wire
10 may be controlled by not providing a dancer section 32 and
configuring the unwinding unit controller 120 to control the speed
of rotation and/or the rotation torque of the unwinding motor 122.
With this configuration, the number of dancer sections 32 in the
wire drawing machine 100 can be further reduced.
[0074] Further, in the unwinding unit 20, for example, a distortion
gauge, etc., may be provided in the guide roller 28 or 30 so as to
measure the tension of the metal wire 10. In that case, the
unwinding unit controller 120 may feedback-control the rotation
torque of the torque motor 38 by using the difference between a set
tension and the tension measured by such distortion gauge, etc., as
a feedback signal. This allows a predetermined tension to be
applied to the metal wire 10 so that the resulting tension of the
metal wire 10 is further closer to the set tension.
[0075] Operation of Wire Drawing Units 40
[0076] Next, the operation of each wire drawing unit 40 drawing the
metal wire 10 delivered from the unwinding unit 20 will be
described.
[0077] The first-stage wire drawing unit 40-1 draws the metal wire
10 by controlling the rotation torque CT1 of the drive capstan 50-1
based on the front tension FT1 of the metal wire 10 passing through
the wire drawing die 42-1. More specifically, the rotation torque
CT1 of the drive capstan 50-1 has the following relationship with
the front tension FT1 of the metal wire 10 passing through the wire
drawing die 42-1 and the back tension BT2 of the metal wire 10
passing through the wire drawing die 42-2 of the second-stage wire
drawing unit 40-2:
CT1=FT1-BT2
[0078] Accordingly, if the front tension FT1 of the first stage can
be measured, the back tension BT2 of the second stage can be
controlled to a predetermined value by controlling the rotation
torque CT1 of the first stage. In this example, the wire drawing
unit controller 140 controls the rotation torque CT1 of the drive
capstan 50-1 based on the front tension FT1 of the metal wire 10
measured by the distortion gauge 156 provided at the guide roller
46-1, so that the back tension BT2 of the second stage becomes a
predetermined value. In other words, the wire drawing unit
controller 140 feed-forward-controls the rotation torque CT1 based
on the front tension FT1. With this control, the metal wire 10 is
pulled through the wire drawing die 42-1 by the drive capstan 50-1
with a pulling force of the front tension FT1 in a non-slip manner,
and is delivered to the wire drawing unit 40-2 in a non-slip manner
with the back tension BT2 being applied. The back tension BT2 is,
for example, around 10% of the yield stress of the metal wire
pulled through the wire drawing die 42-1.
[0079] The second-stage wire drawing unit 40-2 further draws the
metal wire 10 in the same manner as the first-stage wire drawing
unit 40-1. That is, the wire drawing unit controller 140 controls
the rotation torque CT2 of the drive capstan 50-2 based on the
front tension FT2 of the metal wire 10 measured by the distortion
gauge 156 provided at the guide roller 46-2, so that the back
tension BT3 of the third stage becomes a predetermined value.
CT2=FT2-BT3
[0080] Similarly, the wire drawing unit controller 140 controls, in
the i-th stage wire drawing unit 40-i, the rotation torque CTi of
the drive capstan 50i based on the front tension FTi of the metal
wire 10 measured by the distortion gauge 156 provided at the guide
roller 46-i, so that the back tension BTi+1 of the i+1th stage
becomes a predetermined value.
CT(i)=FT(i)-BT(i+1)
[0081] With the above control, the metal wire 10 is pulled through
the wire drawing die 42i by the drive capstan 50i with a drawing
force of the front tension FTi in a non-slip manner, and is
delivered to the wire drawing unit 40i+1 (or wire drawing unit 90)
in a non-slip manner with the back tension BTi+1 being applied.
Note that, in the above formula, if i=n, then BT(i+1) is regarded
as representing the back tension of the metal wire 10 to be drawn
by the wire drawing die 92 in the wire drawing unit 90.
[0082] The wire drawing unit controller 140 in the present example
controls the rotation torque CT of the drive capstan 50 based on
the back tension BTi+1 which is a set value; however, the wire
drawing unit controller 140 may control the rotation torque CT of
the drive capstan 50 by measuring both the front tension FTi and
the back tension BTi+1. Further, the rotation torque CT of the
drive capstan 50 may be controlled by measuring the drawing force
DT in each wire drawing die 42. By doing so, the drawing force in
the wire drawing die 42 can be measured at the time of the wire
drawing operation.
[0083] According to the present example, the drive capstan 50 sets
the back tension BTi+1 of the next stage based on the actually
measured front tension FTi. In other words, in the present example,
since the front tension is actually measured in each stage, an
error caused in the back tension of a particular stage (difference
between the back tension set value and actual value) is not
transferred to the front tension of the particular stage (or the
back tension and front tension of the subsequent stages) and the
error is, thus, not accumulated. In addition, the cause of errors
between the back tension set value and actual value would be
limited to mechanical errors in the drive capstan 50. Thus,
according to the present example, a wire drawing machine with a
sufficiently small difference between the back tension set value
and actual value can be provided.
[0084] Operation of Wire Drawing Unit 90
[0085] Next, the operation of the wire drawing unit 90 drawing the
metal wire 10 delivered from the wire drawing unit 40-n will be
described. In the below description, the operation of the wire
drawing unit 90 will be described mainly with regard to the
differences from the operation of the wire drawing unit 40.
[0086] The wire drawing unit 90 properly adjusts the stress and
distortion in the metal wire 10 drawn in the wire drawing unit 40-n
and determines the wire speed of the metal wire 10 to be delivered
to the winding unit 60.
[0087] More specifically, the metal wire 10 drawn by the wire
drawing die 42-n of the wire drawing unit 40-n has stress or
distortion in a direction perpendicular to the direction in which
the metal wire 10 is delivered, particularly in the case where the
wire drawing die has a large reduction in area. In the wire drawing
die 92, however, a drawing force is applied to the metal wire 10
from its periphery more uniformly than in the wire drawing die
42-n, so that such stress or distortion can properly be
adjusted.
[0088] Further, the drive capstan 98 determines the wire speed of
the metal wire 10 in the wire drawing machine 100. Specifically,
the wire drawing unit controller 140 supplies a rotation speed
command to a drive motor 198 and controls the rotation of the drive
motor 198, so that the wire speed of the metal wire 10 becomes a
speed set in advance. The drive motor 198 controls the speed of
rotation of the drive capstan 98 based on the above command. For
example, the wire drawing unit controller 140 controls the speed of
rotation of the drive capstan 98 so that the metal wire 10
delivered to the winding unit 60 has a wire speed of 1000
m/min.
[0089] The wire drawing unit controller 140 may measure the wire
speed of the metal wire 10 delivered from the drive capstan 98
based on the speed of rotation of the guide roller 96 detected by
the encoder 158 provided at the guide roller 96 and
feedback-control the speed of rotation of the drive motor 198 using
the measured wire speed as a feedback signal.
[0090] According to the present example, since the torque of the
drive capstan 50 in the wire drawing unit 40 and also the speed of
the drive capstan 98 in the wire drawing unit 90 are both
controlled, both the tension and wire speed of the wire metal 10
can be further stabilized during the wire drawing operation.
[0091] Operation of Winding Unit 60
[0092] The winding unit 60 winds up the metal wire 10 delivered
from the unwinding unit 20 and then drawn in each wire drawing unit
40 such that the metal wire 10 has an approximately constant wire
speed. That is, the winding unit controller 160 controls the speed
of rotation of the winding motor 180 so that the wire speed of the
metal wire 10 supplied to the winding unit 60 is maintained at an
approximately constant value.
[0093] In the present embodiment, the winding unit controller 160
controls the speed of rotation of the winding motor 180, for
example, by using the speed of rotation of, i.e., the wire speed of
the metal wire 10 in, the drive capstan 98 which is located before
the winding unit 60 as a feed-forward signal and the pivot angle of
the dancer arm 76 as a feedback signal. More specifically, the wire
speed of the metal wire 10 passing through the drive capstan 98 is
detected by an encoder provided at the drive capstan 98 and is fed
to the wire drawing unit controller 140. Then, the winding unit
controller 160 generates a speed signal indicative of the detected
wire speed as a feed-forward signal and supplies it to the winding
motor 180 to control the rotation of the winding motor 180.
[0094] Further, the winding unit controller 160 generates a
feedback signal based on the pivot angle detected by the
potentiometer 178 and controls the rotation of the winding motor
180.
[0095] To be more specific, the winding unit controller 160
calculates a pivot angle deviation between the pivot angle of the
dancer arm 76 detected by the potentiometer 178 and the pivot angle
of the dancer arm 76 at the reference position. Then, the winding
unit controller 160 determines the rotation speed of the winding
motor 180 so as to approximate the pivot angle deviation to zero,
and provides a rotation speed command to the winding motor 180
based on that determination. Using the pivot angle deviation as a
feedback signal, the winding unit controller 160 controls the
rotation speed of the winding motor 180 through P control, PI
control, PID control, etc.
[0096] With the above operation, the winding unit 60 can maintain
the wire speed of the metal wire 10 delivered from the wire drawing
unit 40-n (in other words, the wire speed of the metal wire 10 in
the drive capstan 98) at an approximately constant value regardless
of the amount of metal wire 10 already wound around the winding
bobbin 80, and at the same time, wind up the metal wire 10 around
the winding bobbin 80 so that there is no gap between the above
wire speed and the wire speed of the metal wire 10 passing through
the guide rollers 68 and 70.
[0097] According to the operations described above, the wire
drawing machine 100 can draw the metal wire 10 wound around the
unwinding bobbin 22 in the wire drawing units 40 and 90 and wind up
the resulting wire around the winding bobbin 80. For example, if
the wire drawing machine 100 has five stages of wire drawing units
40 (i.e., n=5), the metal wire 10 wound around the unwinding bobbin
22 is a piano wire having a diameter of 120 .mu.m and the five wire
drawing dies 42 have die hole diameters of 111 .mu.m, 102 .mu.m, 94
.mu.m, 87 .mu.m and 80 .mu.m, respectively, the metal wire 10 wound
around the winding bobbin 80 will have a diameter of 80 .mu.m.
SECOND EXAMPLE
[0098] In the second example, values of the front tension of the
metal wire 10 measured when rotating the drive capstan 50 of each
wire drawing unit 40 at a controlled speed (such values will
hereinafter be referred to as "sample values") are obtained in
advance and, based on the obtained values, the drive capstan 50 is
rotated at a controlled torque, instead of a controlled speed, so
as to pull out and draw the metal wire 10 through the wire drawing
die 42.
[0099] Before performing the wire drawing operation in the wire
drawing machine 100, the metal wire 10 is first provided in each
wire drawing unit 40 in a tensioned state. In this example, in each
wire drawing unit 40, the tip of the metal wire 10 is processed so
as to be thin and allowed to pass through the die hole of the wire
drawing die 42. After that, the metal wire 10 is pulled through the
wire drawing die 42 by rotating the drive capstan 50 at a
controlled speed and a predetermined length of metal wire 10 is
wound around the drive capstan 50 (this operation will hereinafter
be referred to as a "setting operation"). In this example, the wire
drawing operation is performed by using the front tension of the
metal wire 10 obtained when pulling the metal wire 10 through the
wire drawing die 42 at a controlled speed in such setting
operation, as a sample value FT' of the front tension.
[0100] Operation in Setting operation
[0101] In this example, the metal wire 10 is first provided in the
unwinding unit 20 in a tensioned state and, after that, the metal
wire 10 is provided in the guide roller 44-1, the wire drawing die
42-1 and the guide roller 46-1 of the wire drawing unit 40-1 in a
tensioned state. Then, the wire drawing unit controller 140 rotates
the drive capstan 50-1 at a controlled speed of an approximately
constant value, so as to wind a predetermined length of metal wire
10 around the drive capstan 50-1 (or wind the metal wire 10 for a
predetermined period of time). Here, the wire drawing unit
controller 140 stores the front tension FT1 of the metal wire 10
detected by the distortion gauge 156 provided at the guide roller
46 as a sample value FT1' of the front tension FT1. FT1' may be an
instantaneous value of the front tension FT1 or may alternatively
be an average value.
[0102] In the wire drawing units 40-2 and 3 as well, the wire
drawing unit controller 140 obtains and stores sample values FT2'
and FT3' of the front tensions FT2 and FT3 of the metal wire 10 in
the same manner.
[0103] Next, the operation of the wire drawing machine 100 drawing
the metal wire 10 in this example will be described. Note that
since the unwinding unit 20, the wire drawing unit 90 and the
winding unit 60 in this example operate in the same manner as in
the first example, the following description will be made with
regard to the operation of the wire drawing unit 40.
[0104] Operation of Wire Drawing Unit 40
[0105] The first-stage wire drawing unit 40-1 draws the metal wire
10 by controlling the rotation torque CT1 of the drive capstan 50-1
based on the sample value FT1' of the front tension FT1, obtained
in advance. In this example, FT1' is a sample value obtained in a
state where the back tension set value BT1 is applied to the metal
wire 10. Accordingly, a sample value DT1' of the drawing force of
the wire drawing die 42-1 can be calculated by the following:
DT1'=FT1'-BT1
[0106] The rotation torque CT1 of the drive capstan 50-1 has the
following relationship with the front tension FT1 of the metal wire
10 passing through the wire drawing die 42-1 and the back tension
BT2 of the metal wire 10 passing through the wire drawing die 42-2
of the second-stage wire drawing unit 40-2:
CT1=FT1-BT2
[0107] Further, the front tension FT1, the back tension BT1 and the
drawing force DT1 have the following relationship:
FT1=BT1+DT1
[0108] Thus, the rotation torque CT1 of the drive capstan 50-1 in
this example can be obtained, based on the back tensions BT1 and
BT2 (both being set values) and the drawing force DT1' (sample
value), as follows:
CT1=BT1+DT1'-BT2
[0109] In this example, the wire drawing unit controller 140
feed-forward controls the rotation torque CT1 of the drive capstan
50-1 using the above formula, so that the back tension BT2 will be
a predetermined value based on the back tension set value BT1 and
the drawing force sample value DT1', obtained in advance. As a
result, the metal wire 10 is pulled through the wire drawing die
42-1 by the drive capstan 50-1 with a pulling force of FT1' in a
non-slip manner. Further, the metal wire 10 is, as a setting,
delivered to the wire drawing unit 40-2 in a non-slip manner with
the back tension BT2 being applied.
[0110] Similarly to the first stage wire drawing unit 40-1, the
second stage wire drawing unit 40-2 feed-forward controls the
rotation torque CT2 of the drive capstan 50-2 using the below
formula, so that the back tension BT3 will be a predetermined value
based on the back tension set value BT2 and the drawing force
sample value DT2', obtained in advance.
CT2=BT2+DT2'-BT3
[0111] Likewise, the wire drawing unit controller 140 feed-forward
controls the rotation torque CTi of the drive capstan 50i in the
i-th stage using the below formula, so that the back tension BTi+1
will be a predetermined value based on the i-th stage back tension
set value BTi and the i-th stage drawing force sample value DTi',
obtained in advance.
CT(i)=BT(i)+DT(i)'-BT(i+1)
[0112] As a result, the metal wire 10 is pulled through the wire
drawing die 42i by the drive capstan 50i with a pulling force of
FTi', in a non-slip manner. Further, the metal wire 10 is, as a
setting, delivered to the wire drawing unit 40i+1 (or wire drawing
unit 90) in a non-slip manner with the back tension BTi+1 being
applied. In the above formula, if i=n, then BTi+1 is regarded as
representing the back tension of the metal wire 10 to be drawn by
the wire drawing die 92 of the wire drawing unit 90.
[0113] In this example, DT1' is a drawing force sample value in the
wire drawing operation. In other words, the drawing force is not
actually measured in the wire drawing operation. Thus, even if the
metal wire 10 wound around the drive capstan 50 comes loose, DT1'
does not vary. Accordingly, in this example, it is preferable for
the wire drawing machine 100 to further include a structure to
press the metal wire 10 wound around the drive capstan 50 toward
that drive capstan 50. Such structure for pressing may be, for
example, a roller.
[0114] Further, although, in this example, the front tension values
in the setting operation are obtained as sample values, the way of
obtaining sample values is not limited thereto.
[0115] According to this example, since the rotation torque CT of
the drive capstan 50 is controlled using sample values and any
structure for actually measuring a front tension or back tension,
etc., in the wire drawing operation is not necessary, a wire
drawing machine with a simple configuration can be provided. In
addition, according to this example, since the rotation torque CT
of the drive capstan 50 is controlled using sample values and the
rotation torque CT of the drive capstan 50 does not vary with
disturbance, a wire drawing machine achieving stable operation can
be provided.
THIRD EXAMPLE
[0116] In addition to the second example, the back tension BT of
the metal wire 10 is measured in the third example. In this
example, the rotation torque of the drive capstan 50 at a
particular stage is feed-forward controlled based on the front
tension FT of the particular stage and the back tension BT of the
next stage. Further, in this example, a feedback control is also
performed so that the measured back tension BT will be a
predetermined value.
[0117] Hereinafter, the operation of the wire drawing machine 100
drawing the metal wire 10 in this example will be described. Note
that since the unwinding unit 20, the wire drawing unit 90 and the
winding unit 60 in this example operate in the same manner as those
in the first example and since the sample values are obtained in
the same manner as those in the second example, the below
description will only be made about the operation of the wire
drawing unit 40 during the wire drawing operation.
[0118] Operation of Wire Drawing Unit 40
[0119] The first-stage wire drawing unit 40-1 draws the metal wire
10 by controlling the rotation torque CT1 of the drive capstan 50-1
based on the sample value FT1' of the front tension FT1, obtained
in advance. In this example, FT1' is a sample value obtained in a
state where the back tension measurement value BT1' is applied to
the metal wire 10. Accordingly, a sample value DT1' of the drawing
force of the wire drawing die 42-1 can be calculated based on the
following:
DT1'(sample value)=FT1'(sample value)-BT1' (measurement value)
[0120] The rotation torque CT1 of the drive capstan 50-1 has the
following relationship with the front tension FT1 of the metal wire
10 passing through the wire drawing die 42-1 and the back tension
BT2 of the metal wire 10 passing through the wire drawing die 42-2
of the second-stage wire drawing unit 40-2:
CT1=FT1-BT2
[0121] The wire drawing unit controller 140 feedback controls the
rotation torque CT1 of the drive capstan 50-1 based on the above
formula. That is, the wire drawing unit controller 140 controls the
rotation torque CT1 of the drive capstan 50-1 so as to approximate
the measurement value of the back tension BT2 to the set value.
[0122] Further, the front tension FT1, the back tension BT1 and the
drawing force DT1 have the following relationship:
FT1=BT1+DT1
[0123] In this example, the rotation torque of the drive capstan
50-1 is also controlled in a feed-forward manner, and the amount of
such feed-forward CT1' can be obtained, based on the back tensions
BT1 and BT2 (both being set values) and the drawing force DT1'
(sample value), as follows:
CT1'=BT1(set value)+DT1'(sample value)-BT2(set value)
[0124] In this example, the wire drawing unit controller 140
feed-forward controls the rotation torque CT1 of the drive capstan
50-1 using the above formula, so that the back tension BT2 will be
a predetermined value based on the back tension set value BT1 and
the drawing force sample value DT1', obtained in advance. As a
result, the metal wire 10 is pulled through the wire drawing die
42-1 by the drive capstan 50-1 with a pulling force of FT1' in a
non-slip manner. Further, the metal wire 10 is, as a setting,
delivered to the wire drawing unit 40-2 in a non-slip manner with
the back tension BT2 being applied.
[0125] Similarly to the first stage wire drawing unit 40-1, the
second stage wire drawing unit 40-2 feed-forward controls the
rotation torque CT2 of the drive capstan 50-2 using the below
formula, so that the back tension BT3 will be a predetermined value
based on the back tension set value BT2 and the drawing force
sample value DT2', obtained in advance.
CT2=BT2+DT2'-BT3
[0126] Likewise, the wire drawing unit controller 140 feed-forward
controls the rotation torque CTi of the drive capstan 50i in the
i-th stage using the below formula, so that the back tension BTi+1
will be a predetermined value based on the i-th stage back tension
set value BTi and the i-th stage drawing force sample value DTi',
obtained in advance.
CT(i)=BT(i)+DT(i)'-BT(i+1)
[0127] As a result, the metal wire 10 is pulled through the wire
drawing die 42i by the drive capstan 50i with a pulling force of
FTi', in a non-slip manner. Further, the metal wire 10 is, as a
setting, delivered to the wire drawing unit 40i+1 (or wire drawing
unit 90) in a non-slip manner with the back tension BTi+1 being
applied. In the above formula, if i=n, then BTi+1 is regarded as
representing the back tension of the metal wire 10 to be drawn by
the wire drawing die 92 of the wire drawing unit 90.
[0128] According to this example, since the back tension of the
metal wire 10 is feedback controlled, the difference between the
sample value and the actual value of the drawing force or front
tension can be prevented from being transferred to the back tension
in the next stage and consequently being accumulated, as is the
case with the first example. Further, since the back tension is
measured in this example, the drawing force of the wire drawing die
42 can be calculated based on the measured back tension and the
rotation torque of the drive capstan 50.
[0129] According to the wire drawing machine and wire drawing
method described in the foregoing, since there is no need to
provide a dancer in the wire drawing unit, the configuration can be
simplified. Further, it becomes possible to provide a wire drawing
machine capable of arbitrarily adjusting the conditions of wire
drawing, such as arbitrarily setting the back tension or reduction
in area of the metal wire. Thus, the wire drawing machine and wire
drawing method of the present embodiment can bring about excellent
effects, including arbitrarily setting the back tension so that
deterioration of the wire drawing die can be reduced and
arbitrarily setting the reduction in area so that the number of
wire drawing dies used can be reduced. Furthermore, according to
the wire drawing machine and wire drawing method of the present
embodiment, since the wire drawing conditions, such as the wire
drawing speed, back tension, front tension, etc., can be
arbitrarily adjusted, it is possible to produce metal wires having
various properties in terms of wire diameter, curl diameter, etc.,
and metal wires having excellent properties in terms of breaking
force, tension strength, etc., compared to conventional wires.
[0130] The examples and applications described above through the
embodiments of the invention can be combined as appropriate
depending on the intended purpose of use, or used by making various
modifications or improvements, and the invention is not limited to
the above-described embodiments. It will be apparent from the
description of the attached claims that such combinations or
embodiments in which such modifications or improvements are made
can also fall within the technical scope of the invention.
DESCRIPTION OF REFERENCE NUMERALS
[0131] 10 . . . metal wire; 11 . . . metal wire; 20 . . . unwinding
unit; 22 . . . unwinding bobbin; 22 . . . unwinding motor; 24, 26,
28 . . . guide roller; 32 . . . dancer section; 34 . . . dancer
roller; 36 . . . dancer arm; 38 . . . torque motor; 40 . . . wire
drawing unit; 42 . . . wire drawing die; 44, 46 . . . guide roller;
50 . . . drive capstan; 60 . . . winding unit; 66, 68, 70 . . .
guide roller; 72 . . . dancer section; 74 . . . dancer roller; 76 .
. . dancer arm; 78 . . . torque motor; 80 . . . winding bobbin; 92
. . . wire drawing die; 94, 96 . . . guide roller; 98 . . . drive
capstan; 100 . . . wire drawing machine; 110 . . . system
controller; 120 . . . unwinding unit controller; 122 . . .
unwinding motor; 138 . . . potentiometer; 140 . . . wire drawing
unit controller; 150 . . . drive motor; 152, 156 . . . distortion
gauge; 154, 158 . . . encoder; 160 . . . winding unit controller;
178 . . . potentiometer; 180 . . . winding motor; 200 . . . control
unit; BT . . . back tension; CT . . . rotation torque; DT . . .
drawing force; and FT . . . front tension.
* * * * *