U.S. patent number RE43,636 [Application Number 11/898,201] was granted by the patent office on 2012-09-11 for speed controlled machine tool.
This patent grant is currently assigned to Toshiba Kikai Kabushiki Kaisha. Invention is credited to Koichi Katoh, Yasunori Katoh.
United States Patent |
RE43,636 |
Katoh , et al. |
September 11, 2012 |
Speed controlled machine tool
Abstract
.[.A tool, attachable to a spindle of a machine tool and capable
of changing independently a rotational speed of a cutting tool from
that of the spindle, provided with a cutting tool for machining a
workpiece, an electric motor for driving the machining tool, a
generator for generating electric power to drive the electric motor
by the rotation of the spindle, a tool holding part for rotatably
holding the cutting tool, a casing for holding the electric motor,
the generator, the tool attachment part, and the tool holding part,
and a locking part for preventing rotation of the casing by
engagement with a non-rotating part of the machine tool..]. .Iadd.A
tool includes an AC generator, an AC motor and a case holding the
generator and motor such that the generator and the motor are
arranged in the case along a center axis and a longitudinal
direction of a rotatable portion of the generator. A rotation speed
of an output shaft of the motor is based on a rotation speed of an
input shaft of the generator and a ratio, between a number of poles
of the generator and a number of poles of the motor..Iaddend.
Inventors: |
Katoh; Koichi (Shizuoka-ken,
JP), Katoh; Yasunori (Shizuoka-ken, JP) |
Assignee: |
Toshiba Kikai Kabushiki Kaisha
(Tokyo, JP)
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Family
ID: |
27343586 |
Appl.
No.: |
11/898,201 |
Filed: |
September 10, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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11154997 |
Jun 17, 2005 |
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09866943 |
May 30, 2001 |
6474913 |
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Reissue of: |
10198937 |
Jul 22, 2002 |
6579215 |
Jun 17, 2003 |
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Foreign Application Priority Data
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May 31, 2000 [JP] |
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2000-163437 |
Jun 5, 2000 [JP] |
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2000-168231 |
Aug 22, 2000 [JP] |
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2000-251096 |
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Current U.S.
Class: |
318/461; 388/937;
409/230; 409/234; 483/30; 409/232; 408/238 |
Current CPC
Class: |
B23Q
5/10 (20130101); B23Q 1/0009 (20130101); B23Q
5/048 (20130101); Y10T 409/309296 (20150115); Y10T
483/1736 (20150115); Y10T 409/309408 (20150115); Y10T
409/300896 (20150115); Y10T 409/303752 (20150115); Y10T
408/94 (20150115); Y10T 483/1733 (20150115); Y10T
409/30952 (20150115); Y10T 408/03 (20150115) |
Current International
Class: |
H02P
1/04 (20060101) |
Field of
Search: |
;318/461,140,727
;388/937 ;409/230,232,234 ;408/238 ;483/30 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2014332 |
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Aug 1979 |
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GB |
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363109941 |
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May 1988 |
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JP |
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5-177485 |
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Jul 1993 |
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JP |
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Primary Examiner: Duda; Rina
Attorney, Agent or Firm: Pillsbury Winthrop Shaw Pittman,
LLP
Parent Case Text
This .Iadd.is a divisional (reissue) of application Ser. No.
11/154,997 filed Jun. 17, 2005, now abandoned, which is a Reissue
of application Ser. No. 10/198,937, filed Jul. 22, 2002, U.S. Pat.
No. 6,579,215, .Iaddend.is a divisional of application Ser. No.
09/866,943 filed May 30, 2001, U.S. Pat. No. 6,474,913 which claims
priority to Japanese Patent Application No. 2000-163437 filed May
31, 2000, Japanese Patent Application No. 2000-168231 filed Jun. 5,
2000, and Japanese Patent Application No. 2000-251096 filed Aug.
22, 2000.
Claims
What is claimed is:
1. A machine tool comprising: a machine tool body provided with a
spindle, a driving means for driving said spindle, and at least one
control axis for changing a relative position between said spindle
and a workpiece; a control apparatus for controlling said driving
means and said control axis in accordance with a machining program;
a tool attachable to said spindle and provided with a machining
tool for machining a workpiece, an induction motor for driving said
machining tool, and an alternating current generator for generating
electric power to drive said induction motor by the rotation of
said spindle at a frequency in accordance with the rotational speed
of said spindle, said induction motor rotating at a rotational
speed in accordance with said frequency.
2. A tool attachable to a spindle of a machine tool comprising: a
machining tool for machining a workpiece; an electric motor for
driving said machining tool; and a generator for generating
electric power to drive said electric motor by the rotation of said
spindle; wherein said generator and said electric motor change the
rotational speed of said machining tool from the rotational speed
of said spindle by a predetermined ratio determined based on a pole
number of said generator and said electric motor.
3. A tool attachable to a spindle of a machine tool comprising: a
machining tool for machining a workpiece; an induction motor for
driving said machining tool; and an alternating current generator
for generating electric power to drive said induction motor by the
rotation of said spindle at a frequency in accordance with the
rotational speed of said spindle, said induction motor rotating at
a rotational speed in accordance with said frequency.
4. A tool as set forth in claim 3, wherein said generator is a
three-phase synchronous generator; and said inductor motor is a
three-phase induction motor.
5. A tool as set forth in claim 2, further comprising: a tool
attachment part attachable to said spindle for transmitting the
rotation of said spindle to said generator; a tool holding part for
rotatably holding said machining tool; a casing for holding said
electric motor, said generator, said tool attachment part, and said
tool holding part; and a locking part for preventing rotation of
said casing by engagement with a non-rotating part of said machine
tool.
6. A tool attachable to a spindle of a machine tool comprising: a
machining tool for machining a workpiece; an electric motor for
driving said machining tool; a generator for generating electric
power to drive said electric motor by the rotation of said spindle;
control means for controlling a supply of electric power generated
by said generator to drive and control said machining tool; and
rotation detecting means for detecting a rotational position and/or
rotational speed of said electric motor; wherein: said control
means controls said electric motor based on the detected rotational
position and/or the detected rotational speed.
7. A tool as set forth in claim 6, wherein said control means
comprises: a memory for storing a program for driving and
controlling said machining tool; a processor for performing said
program; and a driving circuit for supplying the electric power
from said generator to said electric motor in response to a control
signal from said processor.
8. A tool attachable to a spindle of a machine tool comprising: a
machining tool for machining a workpiece; an electric motor for
driving said machining tool; a generator for generating electric
power to drive said electric motor by the rotation of said spindle;
control means for controlling a supply of electric power generated
by said generator to drive and control said machining tool;
rotation detecting means for detecting a rotational position and/or
rotational speed of said electric motor; and rotation detecting
means for detecting a rotational position and/or rotational speed
of said spindle; wherein said control means controls said electric
motor based on the detected rotational position and/or rotational
speed of both of said spindle and said electric motor.
9. A machine tool comprising: a machine tool body provided with a
spindle, a driving means for driving said spindle, and at least one
control axis for changing a relative position between said spindle
and a workpiece; a control apparatus for controlling said driving
means and said control axis in accordance with a machining program;
and a tool attachable to said spindle and provided with a machining
tool for machining a workpiece, an electric motor for driving said
machining tool, and a generator for generating electric power to
drive said electric motor by the rotation of said spindle; wherein
said tool changes the rotational speed of said machining tool from
the rotational speed of said spindle by a predetermined ratio
determined based on pole numbers of said generator and said
electric motor.
10. A tool as set forth in claim 6, further comprising: data input
means for inputting various data required for controlling said
electric motor to said control means from outside.
11. A tool holder attachable to a spindle of a machine tool for
rotatably holding a machining tool for machining a workpiece, said
tool holder comprising: an electric motor for driving said
machining tool; and a generator for generating electric power to
drive said electric motor by the rotation of said spindle; wherein
said generator and said electric motor change the rotational speed
of said machining tool from the rotational speed of said spindle by
a predetermined ratio determined based on a pole number of said
generator and said electric motor.
12. A tool holder attachable to a spindle of a machine tool for
rotatably holding a machining tool for machining a workpiece, said
tool holder comprising: an induction motor for driving said
machining tool; and an alternating current generator for generating
electric power to drive said induction motor by the rotation of
said spindle at a frequency in accordance with the rotational speed
of said spindle, said induction motor rotating at a rotational
speed in accordance with said frequency.
13. A machine tool comprising: a machine tool body provided with a
spindle, a driving means for driving said spindle, and at least one
control axis for changing a relative position between said spindle
and a workpiece; a control apparatus for controlling said driving
means and said control axis in accordance with a machining program;
and a tool attachable to said spindle and provided with a machining
tool for machining a workpiece, an electric motor for driving said
machining tool, and a generator for generating electric power to
drive said electric motor by the rotation of said spindle; wherein
said generator and said electric motor change the rotational speed
of said machining tool from the rotational speed of said spindle by
a predetermined ratio determined based on a pole number of said
generator and said electric motor.
14. A tool holder as set forth in claim 11, further comprising: a
tool attachment part attachable to said spindle for transmitting
the rotation of said spindle to said generator; a tool holding part
for rotatably holding said machining tool; a casing for holding
said electric motor, said generator, said tool attachment part, and
said tool holding part; a locking part for preventing rotation of
said casing by engagement with a non-rotating part of said machine
tool.
15. A machine tool as set forth in claim 9, further comprising an
automatic tool changer for attaching said tool to said spindle and
detaching said tool from said spindle.
.Iadd.16. A rotation speed changing apparatus comprising: an AC
generator having an input shaft connectable to a first rotatable
portion and rotatable in response to a rotation of the first
rotatable portion, said AC generator generating AC electric power
when the input shaft is rotated; an AC motor having an output shaft
that is rotated when the AC motor receives the AC electric power
generated by the AC generator; and a case, accommodating and
holding the AC generator and the AC motor, the AC generator and the
AC motor being arranged in the case along a center axis and a
longitudinal direction of the first rotatable portion, wherein a
rotation speed of the output shaft of the AC motor is based on a
rotation speed of the input shaft of the AC generator and a ratio,
between a number of poles of the AC generator and a number of poles
of the AC motor; further comprising a non-rotating portion, fixing
the first rotatable portion and not being rotated by the rotation
of the first rotatable portion, wherein the case comprises a
rotation locking member, inserted into a hole formed in the
non-rotating portion and constraining the rotation of the case, and
wherein when the speed changing apparatus is connected to the first
rotatable portion, the rotation locking member is inserted into the
hole..Iaddend.
.Iadd.17. A rotation speed changing apparatus comprising: an AC
generator having an input shaft connectable to a first rotatable
portion and rotatable in response to a rotation of the first
rotatable portion, said AC generator generating AC electric power
when the input shaft is rotated; an AC motor having an output shaft
that is rotated when the AC motor receives the AC electric power
generated by the AC generator; and a case, accommodating and
holding the AC generator and the AC motor, the AC generator and the
AC motor being arranged in the case along a center axis and a
longitudinal direction of the first rotatable portion, wherein a
rotation speed of the output shaft of the AC motor is based on a
rotation speed of the input shaft of the AC generator and a ratio,
between a number of poles of the AC generator and a number of poles
of the AC motor; wherein the AC generator comprises an AC
synchronous generator, and the AC motor comprises an induction
motor; the case further comprising: a first case member rotatably
holding the first rotatable portion, a second case member,
connected to the first case member, rotatable with the first
rotatable portion and holding the generator and the motor, a third
case member, connected to the second case member, and accommodating
the output shaft of the motor, and a means for clamping and joining
the first case member, the second case member and the third case
member..Iaddend.
.Iadd.18. A rotation speed changing apparatus comprising: an AC
generator having an input shaft connectable to a first rotatable
portion and rotatable in response to a rotation of the first
rotatable portion, said AC generator generating AC electric power
when the input shaft is rotated; an AC motor having an output shaft
that is rotated when the AC motor receives the AC electric power
generated by the AC generator; and a case, accommodating and
holding the AC generator and the AC motor, the AC generator and the
AC motor being arranged in the case along a center axis and a
longitudinal direction of the first rotatable portion, wherein a
rotation speed of the output shaft of the AC motor is based on a
rotation speed of the input shaft of the AC generator and a ratio,
between a number of poles of the AC generator and a number of poles
of the AC motor; the case further comprising: a first case member
rotatably holding the first rotatable portion, a second case
member, connected to the first case member, rotatable with the
first rotatable portion and holding the generator and the motor, a
third case member, connected to the second case member, and
accommodating the output shaft of the motor, and a means for
clamping and joining the first case member, the second case member
and the third case member..Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tool and a tool holder to be
used in a machine tool. More particularly, the present invention
relates to a tool and tool holder removably attachable to the
spindle of a machine tool.
2. Description of the Related Art
In a machine tool provided with a spindle such as machining center,
the maximum rotational speed of the spindle is determined by the
structure of a bearing rotatably supporting the spindle and a
lubrication system of this bearing. For this reason, when it is
necessary to rotate a tool at a higher rotational speed than the
maximum rotational speed of the spindle, an accelerating apparatus
is used.
As the accelerating apparatus, for example, an accelerating
apparatus provided with a gear mechanism such as an epicyclic
gearing which holds the tool and is removably attachable to the
spindle is well known.
However, when raising the rotational speed of the tool to a higher
speed than the maximum rotational speed of the spindle by the above
gear mechanism, the accelerating apparatus increasingly generates
heat at a super high rotational speed such as tens of thousands to
hundreds of thousands of revolutions per minute, so the machining
tolerance of a workpiece can be influenced by the heat. Further, at
the above super high rotational speed, the noise from the
accelerating apparatus can also increase. Furthermore, a highly
reliable precision structure able to withstand the above super high
rotational speed is required for the accelerating apparatus, so
there is the disadvantage that the manufacturing cost becomes
relatively high.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a tool and a tool
holder capable of changing the rotational speed of a machining tool
for machining a workpiece independently from the rotational speed
of a spindle of a machine tool.
Another object of the present invention is to provide a machine
tool provided with the above tool and tool holder.
Still another object of the present invention is to provide a
method of driving the above tool.
Still another object of the present invention is to provide a tool
management system for managing the above tool.
According to a first aspect of the present invention, there is
provided a tool attachable to a spindle of a machine tool
comprising a machining tool for machining a workpiece; an electric
motor for driving the machining tool; and a generator for
generating electric power to drive the electric motor by the
rotation of the spindle.
According to a second aspect of the present invention, there is
provided a tool attachable to a spindle of a machine tool
comprising a machining tool for machining a workpiece; an electric
motor for driving the machining tool; a generator for generating
electric power to drive the electric motor by the rotation of the
spindle; and a control means for controlling a supply of electric
power generated by the generator to drive and control the machining
tool.
According to a third aspect of the present invention, there is
provided a tool attachable to a spindle of a machine tool
comprising a machining tool for machining a workpiece; an electric
motor for driving the machining tool; a generator for generating
electric power to drive the electric motor by the rotation of the
spindle; an electric power receiving part other than the electric
motor for receiving supply of the electric power; a secondary
battery able to supply power to the electric power receiving part;
and a charging circuit for charging the secondary battery with part
of the electric power generated by the generator.
According to a fourth aspect of the present invention, there is
provided a tool attachable to a spindle of a machine tool
comprising a machining tool for machining a workpiece; an electric
motor for driving the machining tool; a generator for generating
electric power, to drive the electric motor by the rotation of the
spindle; a processing circuit for processing data related to
machining of the workpiece by the machining tool; and a
transmitting and receiving circuit for performing at least one of
transmission and reception of a wireless signal indicating
information related to machining of a workpiece by the machining
tool.
According to a fifth aspect of the present invention, there is
provided a tool holder attachable to a spindle of a machine tool
for rotatably holding a machining tool for machining a workpiece,
the tool holder comprising an electric motor for driving the
machining tool and a generator for generating electric power to
drive the electric motor by the rotation of the spindle.
According to a sixth aspect of the present invention, there is
provided a machine tool comprising a machine tool body provided
with a spindle, a driving means for driving the spindle, and at
least one control axis for changing a relative position between the
spindle and a workpiece; a control apparatus for controlling the
driving means and the control axis in accordance with a machining
program; and a tool attachable to the spindle and provided with a
machining tool for machining a workpiece, an electric motor for
driving the machining tool, and a generator for generating electric
power to drive the electric motor by the rotation of the
spindle.
According to a seventh aspect of the present invention, there is
provided a method of driving a tool attachable to a spindle of a
machine tool, the tool being provided with a machining tool for
machining a workpiece, an electric motor for driving the machining
tool, and a generator for generating electric power to drive the
electric motor by the rotation of the spindle, comprising the steps
of generating alternating current having a frequency in accordance
with the rotational speed of the spindle; driving the electric
motor by the generated alternating current; and controlling the
rotational speed of the machining tool in accordance with the
frequency of the alternating current.
According to an eighth aspect of the present invention, there is
provided a tool management system comprising a tool attachable to a
spindle of a machine tool, the tool comprising a machining tool for
machining a workpiece, an electric motor for driving the machining
tool, a generator for generating electric power to drive the
electric motor by the rotation of the spindle, a processing circuit
for processing data related to machining of the workpiece by the
machining tool; a transmitting and receiving circuit for performing
at least one of transmission and reception of a wireless signal
indicating information related to machining of a workpiece by the
machining tool; and a management apparatus for performing at least
one of reception of data from the transmitting and receiving
circuit and transmission of data to the receiving circuit and
managing the data.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and features of the present invention will
be more apparent from the following description of the preferred
embodiments given in relation to the accompanying drawings,
wherein:
FIG. 1 is a view of the configuration of a machining center as an
example of a machine tool according to the present invention;
FIG. 2 is a sectional view of a tool according to the first
embodiment of the present invention;
FIG. 3 is a view of the connection state of a motor and
generator;
FIG. 4 is a view of the configuration of an electrical system of a
tool according to a second embodiment of the present invention;
FIG. 5 is a view of the configuration of an electrical system of a
tool according to a third embodiment of the present invention;
FIG. 6 is a view of the configuration of an electrical system of a
tool according to a fourth embodiment of the present invention;
FIG. 7 is a view of the configuration of an electrical system of a
tool according to a fifth embodiment of the present invention;
FIG. 8 is a sectional view of a tool according to a sixth
embodiment of the present invention;
FIG. 9 is a view of the configuration of an electrical system of a
tool and the configuration of a tool management system using the
same according to the sixth embodiment of the present
invention;
FIG. 10 is a view of the configuration of a machine tool to which
the tool management system is applied; and
FIG. 11 is a view of the configuration of an electrical system of a
tool and the configuration of a tool management system using the
same according to a seventh embodiment of the present
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Below, an explanation will be made of embodiments of the present
invention by referring to the drawings.
First Embodiment
FIG. 1 is a view of the configuration of a machining center as an
example of a machine tool according to the present invention. Note
that the machining center is a numerical control machine tool
capable of so-called combined machining.
In FIG. 1, the machining center 1 is provided with a cross rail 37
having two ends movably supported by shafts of a double housing
type column 38. A ram 45 is provided movably in a vertical
direction (Z-axis direction) via a saddle 44 supported movably on
this cross rail 37.
The saddle 44 is provided with a not illustrated nut part passing
thorough the cross rail 37 in a horizontal direction. A feed shaft
41 with a screw part formed on the outer circumference is screwed
into this nut part.
A servo motor 19 is connected with an end of the feed shaft 41. The
feed shaft 41 is driven to rotate by the servo motor 19.
By the rotation of the feed shaft 41, the saddle 44 moves in the
Y-axis direction. By this, the ram 45 is moved and positioned in
the Y-axis direction.
Further, the saddle 44 is provided with a not illustrated nut part
in the vertical direction. The feed shaft 42 with a screw part
formed on the outer circumference is screwed into this nut part. A
servo motor 20 is connected with an end of the shaft 42.
The servo motor 20 drives the feed shaft 42 to rotate. By this, the
ram 45 movably provided on the saddle 44 is moved and positioned in
the Z-axis direction.
The ram 45 has built into it a spindle motor 31. This spindle motor
31 rotates a spindle 46 rotatably supported by the ram 45. A tool T
such as an end mill is attached at the front end of the spindle 46.
The tool is driven by the rotation of the spindle 46.
Below the ram 45, a table 35 is provided movably in the X-axis
direction. The table 35 is provided with a not illustrated nut
part. A not illustrated nut feed shaft provided along the X-axis
direction is screwed into this nut part. This not illustrated feed
shaft is connected to the servo motor 20.
The table 35 is moved and positioned in the X-axis direction by the
rotation and driving of the servo motor 18.
Further, the double housing column 38 is provided with a not
illustrated nut part. The cross rail 37 is raised and lowered by
the rotation of the feed shaft 32a screwed into it by a cross rail
elevation motor 32.
An automatic tool changer (ATC) 39 automatically changes the tool T
attached to the spindle 46.
That is, the automatic tool changer 39 holds various tools in its
not illustrated magazine, returns the tool T attached to the
spindle by a not illustrated tool changing arm into the magazine,
and attaches a required tool held by the magazine to the spindle by
the tool changing arm.
A numerical control apparatus 51 drives and controls the above
servo motors 18, 19, and 20, the cross rail elevation motor 32, and
the spindle motor 31.
Specifically, the numerical control apparatus 51 controls the
positions and the speeds between a workpiece and the tool T by the
servo motor 18, 19, and 20 according to a machining process defined
in advance in a machining program. Further, the numerical control
apparatus 51 controls the rotational speed of the spindle 46 by
decoding the rotational speed of the spindle 46 defined by an
S-code in the machining program.
Still further, the numerical control apparatus 51 automatically
changes various tools by decoding the tool changing operation of
the tool T defined by for example an M-code in the machining
program.
FIG. 2 is a sectional view of a tool according to the first
embodiment of the present invention.
In FIG. 2, a tool 60 is comprised of a cutting tool 100 and a tool
holder 61. Note that the cutting tool 100 is an embodiment of a
machining tool according to the present invention.
The tool holder 61 has an attachment part 62, a casing 65 comprised
of casing parts 66, 67, and 68, a generator 70, an electric motor
80, a tool holding part 90, and a locking part 85.
The attachment part 62 is provided with a grip part 62a, a taper
shank 62b to be attached to a taper sleeve 46a formed at the front
end of the above spindle 46, a pull stud 62c formed at the front
end of this taper shank 62b, and a shaft portion 62d rotatably held
by the casing part 66.
The grip part 62a of the attachment part 62 is gripped by the above
tool changing arm of the automatic tool changer 39 when the tool 60
is being attached to the spindle 46 from the magazine of the
automatic tool changer 39 and when the tool 60 is being conveyed
from the spindle to the magazine of the automatic tool changer
39.
The center of the taper shank 62b of the attachment part 62 becomes
concentric with the center of the spindle 46 by being attached to
the taper sleeve 46a of the spindle 46.
The pull stud 62c of the attachment part 62 is clamped by a collet
of a not illustrated clamping mechanism built in the spindle 46
when the attachment part 62 is attached to the taper sleeve 46a of
the spindle 46. Note that the clamping mechanism built in the
spindle 46 is well known, so a detailed explanation of it will be
omitted.
The shaft portion 62d of the attachment part 62 is supported
rotatably held by the inner circumference of the casing part 66 via
a plurality of bearings 72.
The shaft portion 62d of the attachment part 62 is connected with
the input shaft 71 of the generator 70. As this generator 70, for
example, a three-phase synchronous generator can be used.
The electric power generated by the generator 70 is supplied to the
electric motor 80. As this electric motor 80, for example, a
three-phase induction motor can be used.
For example, in a case where a three-phase synchronous generator is
used as the generator 70 and a three-phase induction motor is used
as the electric motor 80, as shown in FIG. 3, the generator 70 and
the electric motor80 are connected by three power cables Wx, WY,
and Wz. The electric motor 80 receives a supply of three-phase
alternating current generated by the generator 70 through the three
power cables.
The tool holding part 90 has a rotatable shaft 91, a coupling 93
for connecting this rotatable shaft 91 and the output shaft 81 of
the electric motor 80, and a tool attachment part 95.
The rotatable shaft 91 is rotatably held by the inner circumference
of the casing part 68 via a plurality of rolling bearings 72.
The front end side of the rotatable shaft 91 is prevented from
detaching from the casing part 68 by a stopper 94.
The cutting tool 100 is held by the tool attachment part 95. This
cutting tool 100 machines a workpiece.
Specifically, as the cutting tool 100, a cutting tool such as a
drill or an end mill may be used.
The casing parts 66, 67, and 68 are connected each other by
clamping means such as bolts. The casing 65 is constructed by these
casing parts 66, 67, and 68.
A locking part 85 is mounted on the outer circumference of the
casing part 66.
When the attachment part 62 is attached to the taper sleeve 46a of
the spindle 46, the front end of the locking part 85 is inserted to
an engagement hole 47a formed at a non-rotating part such as the
ram 45 on the side of the spindle 46.
Due to this, even if the spindle 46 is rotated, rotation of the
casing 65 is prevented.
Next, an explanation will be made of an example of the operation of
the above configured tool 60.
First, the automatic tool changer 39 attaches the tool holder 61
holding the cutting tool 100 at the tool attachment holder 95 to
the spindle 46 of the machining center 1. The front end 85a of the
locking part 85 is inserted into the engagement hole 47a of the
non-rotating part 47 whereby the rotation of the casing 65 is
prevented.
By rotating the spindle at the rotational speed of N.sub.0 from
this state, the attachment part 62 of the tool holder 61 is
rotated, and the rotation of the spindle 46 is transmitted to the
generator 70. By this, the generator 70 generates electric power.
In the case of a three-phase synchronous generator as the generator
70, the generator 70 generates three-phase alternating current.
The frequency F of the three-phase alternating current generated by
the generator 70, as the pole number of the generator 70 is p.sub.1
and the rotational speed of the spindle 46 is N.sub.0 [rpm], is
expressed by the following formula (1). F=p.sub.1*N.sub.0/120 [Hz]
(1)
Accordingly, when the spindle 46 is rotated at the rotational speed
N.sub.0, a three-phase alternating current having the frequency F
expressed the above formula (1) is supplied to the electric motor
80.
Here, in case where a three-phase induction motor is used as the
electric motor 80, as the pole number of the electric motor 80 is
p.sub.2, the electric motor 80 is rotated by 2/p.sub.2 per cycle of
the three-phase alternating current.
Therefore, the synchronous rotational speed of the electric motor
80 is expressed by the following formula (2). N.sub.1=120*F/p.sub.2
(2)
Accordingly, the relationship of the rotational speed N.sub.1 of
the cutting tool 100 to the rotational speed N.sub.0 of the spindle
46 is expressed by the following formula (3).
N.sub.1=N.sub.0*p.sub.1/p.sub.2 [rpm] (3)
As understood from formula (3), the rotational speed N.sub.0 of the
spindle 46 is changed to the rotational speed N.sub.1 expressed by
the above formula (3).
As expressed by the formula (3), it is found that by appropriately
setting the ratio between the pole number p.sub.1 of the generator
70 and the pole number p.sub.2 of the electric motor 80, it is
possible to freely set the ratio of the rotational speed of the
cutting tool 100 to the rotational speed of the spindle 46.
That is, in the case where it is intended to raise the rotational
speed of the cutting tool 100 higher than that of the spindle 46,
the ratio of the pole number p.sub.1/p.sub.2 is set larger than 1.
When it is intended to reduce the rotational speed of the cutting
tool 100 to lower than that of the spindle 46, the ratio of the
pole number p.sub.1/p.sub.2 is set smaller than 1.
Next, an explanation of the driving method of the above configured
tool will be made.
When machining a workpiece comprised of a difficult-to-cut material
such as aluminum alloy, sometimes the rotational speed of the
cutting tool 100 is raised higher than the maximum rotational speed
of the spindle 46.
In such a case, the tool 60 is held in advance in the magazine of
the automatic tool changer 39 of the machining center 1.
For example, when the maximum rotational speed Nmax of the spindle
46 of the above machining center 1 is 3000 rpm and the rotational
speed of the cutting tool 100 is raised to 30,000 rpm, the
generator 70 and the electric motor 80 having a ratio of the pole
number p.sub.1/p.sub.2 of 10 are used.
The automatic tool changer 39 attaches the tool 60 automatically to
the spindle 46 in the same way as an ordinary tool. Note that an
ordinary tool is a tool having a cutting tool clamped by a tool
holder.
The rotational speed of the cutting tool 100 held by the tool
holder 61 is controlled by the rotational speed of the spindle 46.
Specifically, in the machining program downloaded in the numerical
control apparatus 51, the rotational speed of the spindle 46 is
designated in advance by an S-code in accordance with the
rotational speed of the cutting tool 100 held by the tool holder
61. For example, when rotating the cutting tool 100 at the
rotational speed of 30,000 rpm, the rotational speed of the spindle
46 is designated as 3000 rpm by the S-code in the machining
program.
When the spindle 46 is rotated at the rotational speed of 3000 rpm,
the generator 70 generates a three-phase alternating current having
a frequency in accordance with the rotational speed of the spindle
46 and the pole number of the generator 70 and electric motor
80.
The electric motor 80 is driven by the three-phase alternating
current supplied from the generator 70, while the cutting tool 100
held by the tool holder 61 is rotated at the rotational speed of
about 30,000 rpm.
In the above state where the rotational speed of the cutting tool
100 is increased, by moving the workpiece fixed on the table 35
relative to the cutting tool 100 (spindle 46) in accordance with
the machining program, the workpiece is cut.
By this, it becomes possible to appropriately cut a workpiece
comprised of a difficult-to-cut material such as aluminum
alloy.
In this way, according to the present embodiment, the rotational
speed of the cutting tool 100 is raised by driving the motor 80 by
the electric power generated by the generator 70. Due to this, even
if the spindle 46 is rotated at a high rotational speed, heat is
not increasingly generated such as in a gear apparatus, so a
reduction of the machining tolerance due to the heat can be
avoided.
Further, in this embodiment, the rotational speed of the cutting
tool 100 is changed by using the generator 70 and electric motor
80. Therefore, it is possible to decrease the cost and noise of the
tool 60 compared with the case using a transmission mechanism such
as a gear apparatus.
Further, according to this embodiment, the tool 60 can be attached
to the spindle 46 and changed by the automatic tool changer 39 in
the same way as an ordinary tool. Due to this, it is possible to
immediately respond to a need for high speed rotation of the
cutting tool 100.
Further, according to this embodiment, the cutting tool 100 is
driven by the electric power generated by the rotation of the
spindle 46. For this reason, it is not necessary to supply electric
power from outside of the tool, so a cable for supplying electric
power is not necessary between the spindle 46 and the tool 60.
Further, in this embodiment, a three-phase synchronous generator is
used as the generator 70 and a three-phase induction motor is used
as the electric motor 80. Due to this, it becomes possible to
easily control the rotational speed of the cutting tool 100 by the
rotational speed of the spindle 46. That is, since the three-phase
synchronous generator generates voltage having a frequency
precisely proportional to the rotational speed of the spindle 46
and since the three-phase induction motor drives the cutting tool
100 at a rotational speed proportional to this frequency, the
rotational speed of the cutting tool 100 can be easily and
precisely controlled by the rotational speed of the spindle 46 and
the pole number ratio between the three-phase synchronous generator
and the three-phase induction motor.
Further, no position detecting element for detecting the rotational
position of a rotor is needed for the electric motor 80. Due to
this, no cable is needed between the numerical control apparatus 51
and the tool holder 51, so complete separation of the tool 60 from
the spindle 46 becomes possible.
Note that in the above embodiment, the explanation was made of the
case of application to high speed machining of an aluminum alloy,
but the present invention can be applied to any machining requiring
acceleration of the rotational speed of the spindle 46. For
example, the present invention can be applied to machining of
various super difficult-to-cut materials such as cemented carbide,
silicate glass, and ceramics.
Further, in the above embodiment, the explanation was made of the
case of increasing the rotational speed of the cutting tool 100
from the rotational speed of the spindle 46, but decreasing the
rotational speed of the cutting tool 100 from the rotational speed
of the spindle 46 is also possible.
Further, in the above embodiment, the explanation was made of the
case of use of a three-phase synchronous generator as the generator
70 and use of a three-phase induction motor as the electric motor
80, but it is also possible to employ a configuration changing the
rotational speed of the spindle 46 by a combination of a direct
current generator and a direct current motor. The rotational speed
of the direct current motor is determined by voltage supplied from
the direct current generator and the load. For this reason, it is
difficult to directly control the rotational speed of the cutting
tool 100 by the rotational speed of the spindle 46.
By measuring the output characteristic and the load characteristic
of the direct current generator and the direct current motor in
advance, it becomes possible to change the rotational speed of the
spindle 46 at a constant speed ratio by the combination of the
direct current generator and the direct current motor.
Further, it is possible to use another kind of generator and
motor.
Second Embodiment
FIG. 4 is a view of the configuration of the electrical system of a
tool according to a second embodiment of the present invention.
Note that the mechanical structure of the tool according to the
present embodiment is the same as the above mentioned
embodiment.
As shown in FIG. 4, the tool according to the present embodiment is
provided with an alternating current generator as the generator 70,
a direct current motor as the electric motor 80, and a rectifier
circuit 201.
The rectifier circuit 201 rectifies alternating current generated
by the generator 70 and supplies it to the electric motor 80. This
rectifier circuit 201 is built in, for example, the above casing
65.
The amount of the direct current supplied from the rectifier
circuit 201 is defined by the rotational speed of the spindle 46.
On the other hand, the rotational speed of the direct current motor
can be controlled in accordance with the amount of the supplied
current. Accordingly, by controlling the rotational speed of the
spindle 46, control of the speed of the electric motor 80 becomes
possible.
In this way, according to the present invention, even if an
alternating current generator is used as the generator 70 and a
direct current motor is used as the electric motor 80, by providing
the rectifier circuit 201 at the tool, it is possible to change the
rotational speed of the cutting tool 100 from the rotational speed
of the spindle 46.
Note that in the above embodiment, a configuration where the
rectifier circuit 201 was built in the casing 65 was employed, but
it is also possible to employ a configuration where the rectifier
circuit 201 is housed in a box or the like and this is attached to
the outside of the casing 65.
Further, it is also possible to employ a configuration where a
cavity is formed at the casing 65 and the cavity houses the
rectifier circuit 201.
Third Embodiment
FIG. 5 is a view of the configuration of the electrical system of a
tool according to a third embodiment of the present invention. Note
that the mechanical structure of the tool according to the present
embodiment is the same as the above mentioned first embodiment.
In the above first and second embodiments, the rotational speed of
the cutting tool 100 of the tool 60 is controlled by the rotational
speed of the spindle 60, namely, the input rotational speed of the
generator 70.
In the present embodiment, an explanation will be made of a
configuration enabling control of the rotational speed of the
cutting tool 100 regardless of the input rotational speed of the
generator 70.
As shown in FIG. 5, the tool according to the present embodiment is
provided with a generator 70 comprised of an alternating current
generator, an electric motor 80, a rectifier circuit 302, an
inverter 303, and a control circuit 304.
The rectifier circuit 302, the inverter 303, and the control
circuit 304 are incorporated in the above casing 65. Note that it
is possible to employ a configuration where at least some of these
rectifier circuit 302, inverter 303, and control circuit 304 are
housed in a box mounted on the outside of the casing 65.
Further, it is also possible to employ a configuration where a
cavity is formed on the casing 65 and the cavity houses these
rectifier circuit 302, inverter 303, and control circuit 304.
Further, the rectifier circuit 302 supplies part of the rectified
direct current to the control circuit 304.
The inverter 303 changes the direct current supplied from the
rectifier circuit 302 into alternating current for driving the
electric motor 80. For example, the inverter 303 is configured by a
pulse width modulation (PWM) inverter.
The control circuit 304 is provided with a microprocessor 305, a
read only memory (ROM) 306, a random access memory (RAM) 307, a
counter circuit 308, an analog-to-digital (A/D) converter 310, and
a digital-to-analog (D/A) converter 309.
The ROM 306 stores a control program for controlling the electric
motor 80. The control program performs for example variable speed
control of the electric motor 80 by field-oriented control.
The RAM 307 stores data for operations of the microprocessor
305.
The microprocessor 305 executes the control program stored in the
ROM 306, performs various operations, and outputs control signals
304s to the inverter 300 via the D/A converter 309. The control
signals 304s are for example PWM control signals.
The A/D converter 310 converts the value of the current supplied
from the inverter 303 to the electric motor 80 detected by a
current detector 312 into a digital signal.
The electric motor 80 is provided with a rotational position
detector 311. As this rotational position detector 311, for
example, an optical rotary encoder or a resolver may be used.
The counter circuit 308 counts pulse signals detected by the
rotational position detector 311 in accordance with the rotation of
the electric motor 80 and outputs the count to the microprocessor
305.
The above configured control circuit 304 can operate by receiving
electric power generated by the generator 70 by the rotation of the
spindle 46.
The control circuit 304 receives the rotation and the drive current
of the electric motor 80 as input. Due to this, by preparing a
desired control program in the ROM 306 of the control circuit 304
in advance, various control of the electric motor 80 becomes
possible.
For example, when a synchronous motor is used as the electric motor
80 and it is intended to variably control the speed of this
synchronous motor, velocity reference data is set in advance in the
ROM 306. By this, speed control of the electric motor 80 becomes
possible in accordance with this velocity reference data.
Accordingly, according to the present embodiment, control of the
rotational position, the rotational speed, and the torque of the
cutting tool 100 becomes possible regardless of the rotational
speed of the spindle 46. That is, in the present embodiment, it
becomes possible to drive and control the cutting tool 100
separately at the tool side.
Fourth Embodiment
FIG. 6 is a view of the configuration of the electrical system of a
tool according to a fourth embodiment of the present invention.
Note that the mechanical structure of the tool according to the
present embodiment is the same as the above mentioned first
embodiment.
The point of difference between the configuration of the present
embodiment and the configuration explained in the third embodiment
is that the generator 70 is provided with a rotational position
detector 402 and the signal detected by this rotational position
detector 402 is input to the microprocessor 305 via a counter
circuit 403. The rest of the configuration of the present
embodiment is exactly the same as that of the third embodiment.
The rotational position detector 402 is mounted to the input shaft
71 of the generator 70 and detects the rotation of the input shaft
71. As the rotational position detector 402, for example, an
optical rotary encoder or a resolver may be used.
By detecting the amount of rotation of the input shaft 71 by the
rotational position detector 402, the rotation of the spindle 46 is
input to the control circuit 304.
In the control circuit 304, by calculating the difference per unit
time of the rotation received from the counter circuit 403, it
becomes possible to determine the rotational speed of the spindle
46.
Accordingly, by preparing in advance a program for generating
velocity references having a constant speed ratio to the rotational
speed of the spindle 46 in the ROM 306, it becomes possible to
accurately control the rotational speed of the electric motor 80
with respect to that of the spindle 46. That is, by employing the
configuration of the present embodiment, it becomes possible to
accurately control the rotational speed of the spindle 46 in the
same way as a gear apparatus.
Further, in the control circuit 304, both of the rotational
position of the spindle 46 and the rotational position of the
electric motor 80 can be obtained, so it becomes possible to make
the rotational position of the spindle 46 and the rotational
position of the electric motor 80 exactly match.
Fifth Embodiment
FIG. 7 is a view of a configuration of the electrical system of a
tool according to a fifth embodiment of the present invention.
Note that the mechanical structure of the tool according to the
present embodiment is the same as the above mentioned first
embodiment.
The point of difference between the configuration of the present
embodiment shown in FIG. 7 and the configuration explained in the
third embodiment is that a data input unit 501 is added to the
control circuit 304. The rest of the configuration of the present
embodiment is exactly the same as that of the third embodiment.
The data input unit 501 inputs various types of data for
controlling the electric motor 80 from the outside to the control
circuit 304.
Specifically, the data input unit 501 can be configured by switches
mounted on the casing 65 which are operable from outside the casing
65.
The data input unit 501 can be also configured by a receiving
apparatus mounted on the outside of the casing 65 for receiving
wireless signals. According to this configuration, it becomes
possible to input data in real time while machining by the
tool.
The data input from the data input unit 501 includes for example
various types of data such as velocity references to the electric
motor 80 or control parameters.
In the present embodiment, by employing the above configuration, it
is possible to freely change the content of the control of the
electric motor 80. For example, when machining conditions are
changed, it becomes possible to easily change the rotational speed
of the electric motor 80.
Sixth Embodiment
FIG. 8 is a sectional view of a tool according to a sixth
embodiment of the present invention. Note that in FIG. 8, parts
corresponding to those in the tool 60 according to the first
embodiment are assigned the same reference numerals.
The tool 160 shown in FIG. 8 is configured from the cutting tool
100 and a tool holder 161.
The tool holder 161 is provided with a secondary battery 110, a
processing board 300, and an antenna 141 in addition to the
attachment part 62, the casing 65, the generator 70, the electric
motor 80, the tool holding part 90, and the locking part 85.
The secondary battery 110 is fixed inside of the casing part 67.
This secondary battery 110 stores part of the electric power
generated by the generator 70. As the secondary battery 110, for
example, a nickel-cadmium battery may be used. Besides this, a
nickel-hydrogen battery, a lithium battery, or a small-sized lead
storage battery can be also used.
The antenna 141 is fixed on the outside surface of the casing part
65.
The processing board 300 is fixed inside of the casing 65. This
processing board 300 is electrically connected with the secondary
battery 110 and antenna 141.
FIG. 9 is a view of the configuration of the electrical system of
the tool and the configuration of the tool management system
according to the sixth embodiment of the present invention.
In FIG. 9, the tool 160 is provided with a charging circuit 120, a
processing circuit 150, and a transmitting and receiving circuit
140 in addition to the above generator 70, the electric motor 80,
the secondary battery 110, and the antenna 141.
Further, the tool management system according to the present
embodiment is comprised of the tool 160 and a management apparatus
400.
The charging circuit 120, the processing circuit 150, and the
transmitting and receiving circuit 140 are formed on the above
processing board 300. The charging circuit 120 charges the
secondary battery 110 with a part of the electric power generated
by the generator 70. This charging circuit 120 is comprised of a
rectifier circuit for rectifying the alternating voltage generated
by the generator 70, a smoothing circuit for smoothing the ripple
included in the output voltage of this rectifier circuit and
converting it into appropriate voltage, etc.
The secondary battery 110 supplies the electric power charged by
the charging circuit 120 to the power receiving part 170 having the
processing circuit 150 and the transmitting circuit 150.
The processing circuit 150 operates by receiving the electric power
supplied from the secondary battery 110 and processes information
related to the machining of a workpiece by the cutting tool
100.
Here, the information related to the machining of a workpiece by
the cutting tool 100 includes, for example, tool information of a
predetermined format for identifying the tool 160, monitor
information concerning the rotational state of the generator 70 or
the electric motor 80 during machining, etc. Further, the
information related to the machining of a workpiece by the cutting
tool 100 also includes information about the detected rotational
position and the detected rotational speed of the electric motor
80.
The tool information includes for example information about the
type of the cutting tool 100 such as drill or end mill, size of the
cutting tool 100 such as diameter or length, etc.
The monitor information includes information about disconnection or
short-circuits of cables in the generator 70 or the electric motor
80, overload of the electric motor 80, etc.
The processing circuit 150 first generates the above tool
information of the predetermined format. Further, the processing
circuit 150 detects the generated current 70s of the generator 70
or drive current 80s of the electric motor 80, monitors for an
irregular state of the generator 70 or the electric motor 80 based
on the detected information, adds this monitor information to the
tool information, and transmits this tool information to the
transmitting and receiving circuit 140.
The transmitting and receiving circuit 140 transmits the data from
the processing circuit 150 to the management apparatus 400 as a
wireless signal by the antenna 141.
The charging circuit 120, the processing circuit 150, and the
transmitting and receiving circuit 140 can be incorporated in the
casing 65. Note that it is also possible to house the processing
circuit 150 and the transmitting and receiving circuit 140 in a box
and mount the box to the outside of the casing 65. Further, it is
also possible to employ a configuration where a cavity is formed on
the casing 65 and the charging circuit 120 and the processing
circuit 150 and the transmitting and receiving circuit 140 are
housed in the cavity.
The management apparatus 400 is provided with an antenna 401 which
receives data from the antenna 141. This management apparatus 400
is provided with a utility program for monitoring and managing the
tool 160 based on the data from the antenna 141. Note that the
management apparatus 400 is configured by for example a personal
computer.
Further, as shown in FIG. 10, the management apparatus 400 is
connected to the numerical control apparatus 51. In a case of an
irregular state such as a fault in the tool 160, the management
apparatus 400 transmits this irregular state information to the
numerical control apparatus 51.
Next, an explanation, will be given of an example of the operation
of the above configured tool 160.
The automatic tool changer 39 attaches the tool holder 161 holding
the cutting tool 100 to the spindle 46 of the machining center 1.
The front end 85a of the locking part 85 is inserted into the
engagement hole 47a of the non-rotating part 47, whereby rotation
of the casing 65 is prevented.
When the spindle 46 is rotated at predetermined rotational speed
from this state, the attachment part 62 of the tool holder 161 is
rotated, so the rotation of the spindle 46 is transmitted to the
generator 70.
For example, in case where a three-phase synchronous is used as the
generator 70, three-phase alternating current is generated.
A part of this three-phase alternating current is charged into the
secondary battery 110 by the charging circuit 120.
The processing circuit 150 and the transmitting and receiving
circuit 140 become operable by the charge of the secondary battery
110.
When the processing circuit 150 becomes operable, the processing
circuit 150 generates the tool information of a predetermined
format and transmits this tool information to the transmitting and
receiving circuit 140.
The transmitting and receiving circuit 140 transmits the tool
information of a predetermined format to the management apparatus
400.
When an irregular state of the generator 70 or the electrical motor
80 occurs while machining a workpiece by the cutting tool 100,
irregular state information is transmitted to the management
apparatus 400 in addition to the tool information.
Further, if the secondary battery is charged, even after the
rotation of the spindle 46 stops, the processing circuit 150 and
the transmitting and receiving circuit 140 can transmit various
types of data such as tool information or irregular state
information to the management apparatus 400.
For example, when the management apparatus 400 has obtained the
irregular state information from the transmitting and receiving
circuit 140, the management apparatus 400 transmits this irregular
state information to the numerical control apparatus 51. When
receiving the irregular state information, the numerical control
apparatus 51 controls the automatic tool changer 39 so as to detach
the tool 160 from the spindle 46.
According to the present embodiment, the tool 160 is provided with
the secondary battery 110 and can use the electric power stored in
this secondary battery 110 in the power receiving part 170 other
than the electric motor 80. Due to this, it is possible to operate
various circuits incorporated in or added to the tool 160
regardless of the rotation of the spindle 46, and it is possible to
transmit and receive data even during stoppage of the spindle
46.
Further, according to the present embodiment, by the management
apparatus 400 collecting information from the tool 160,
comprehensive management of the tool 160 becomes possible.
Seventh Embodiment
FIG. 11 is a view of the configuration of the electrical system of
a tool and the configuration of a tool management system according
to a seventh embodiment of the present invention.
Note that the mechanical structure of the tool according to the
present embodiment is the same as the sixth embodiment. In FIG. 11,
the parts corresponding to those in the tool 160 according to the
sixth embodiment use the same reference numerals.
In the above sixth embodiment, the management apparatus 400 only
received the data from the tool 160, but in the present embodiment,
an explanation will be made of a configuration enabling
transmission and reception of data between the management apparatus
400 and the tool 260.
As shown in FIG. 11, the tool 260 according to the present
embodiment is provided with a rectifier circuit 200, an inverter
210, and a power receiving part 270 in addition to the generator 70
comprised of an alternating current generator, the electric motor
80 comprised of an induction motor, the secondary battery 110, and
the charging circuit 120.
Further, the rectifier circuit 200, the inverter 210, and the power
receiving part 270 are housed in the casing 65. Note that it is
possible to employ a configuration where at least some or these
rectifier circuit 200, inverter 210, and power receiving part 270
are housed in a box mounted on the outside of the casing 65.
Further, it is also possible to employ a configuration where a
cavity is formed in the casing 65, and the rectifier circuit 200,
the inverter 210, and the power receiving part 270 are housed in
the cavity.
The rectifier circuit 200 rectifies alternating current generated
by the generator 70 and supplies it to the inverter 210.
The inverter 210 changes the supplied direct current from the
rectifier circuit 200 to alternating current for driving the
electric motor 80. For example, the inverter 210 is comprised of a
PWM inverter.
The charging circuit 120 charges the secondary battery 110 with
part of the electric power generated by the generator 70. This
charging circuit 120 is comprised of a rectifier circuit for
rectifying the alternating voltage generated by the generator 70, a
smoothing circuit for smoothing the ripple included in the output
of this rectifier circuit and converting it into appropriate
voltage, etc.
The secondary battery 110 supplies the electric power charged by
the charging circuit 120 to the electric power receiving part
270.
The electric power receiving part 270 is comprised of a processing
circuit part 504 and the transmitting and receiving circuit 240 and
is operated by electric power supplied from the secondary battery
110.
The transmitting and receiving circuit 240 transmits the data
related to machining of a workpiece by the cutting tool 100 to the
management apparatus 400 and receives data related to machining of
a workpiece by the cutting tool 100 from the management apparatus
400 via an antenna 241.
The processing circuit part 504 processes the information related
to machining of a workpiece by the cutting tool 100. This
processing circuit part 504 is provided with a microprocessor 505,
a read only memory (ROM) 506, a random access memory (RAM) 507, a
counter circuit 508, an analog-to-digital(A/D) converter 510, and a
digital-to-analog converter 509.
The ROM 506 stores a control program for controlling the electric
motor 80. The control program performs for example variable speed
control of the electric motor 80 by field-oriented control.
Further, the ROM 506 stores a program for generating tool
information of a predetermined format or monitoring an irregular
state of the tool, a program for transmitting various types of data
to the transmitting and receiving circuit 240 and receiving various
types of data from the transmitting and receiving circuit 240,
etc.
The RAM 507 stores data for operations of the microprocessor 505,
data transmitted from the transmitting and receiving circuit 240,
etc.
The microprocessor 505 executes the control program stored in the
ROM 506. Specifically, the microprocessor 505 performs various
operations, outputs control signals 504s to the inverter 210 via
the D/A converter 509, transmits data to the transmitting and
receiving circuit 240, and receives data from the transmitting and
receiving circuit 240. The control signals 504s are for example PWM
control signals.
The A/D converter 510 converts values detected by a current
detector 312 of the current supplied from the inverter 210 to the
electric motor 80 into a digital signal.
The electric motor 80 is provided with a rotational position
detector 311. As this rotational position detector 311, for
example, an optical rotary encoder or a resolver may be used.
The counter circuit 508 counts pulse signals detected by the
rotational position detector 311 in accordance with the rotation of
the electric motor 80 and transmits the count as output to the
microprocessor 305.
When the tool 260 is attached to the spindle 46 and the spindle 46
is rotated, the secondary battery 110 is charged by the charging
circuit 120. By this, the power receiving part 270 becomes operable
by the electric power supplied from the secondary battery 110.
The rotation and the drive current of the electric motor 80 are fed
back to the processing circuit part 504, so by preparing in advance
a desired program in the ROM 506 of the processing circuit part
504, various control of the electric motor 80 becomes possible.
Further, it is also possible to transmit this control program to
the tool 260 from the management apparatus 400, receive this by the
transmitting and receiving circuit 240, and store it in the RAM
507.
The microprocessor 505 generates tool information of a
predetermined format and transmits the information to the
management apparatus 400 through the transmitting and receiving
circuit 240. The management apparatus 400 manages this tool
information.
Further, the information of the rotational position and the drive
current of the electric motor 80 are fed back to the microprocessor
505, so it is also possible to transmit sequentially this feedback
information to the management apparatus 400 together with the above
tool information.
The management apparatus 400 can monitor data such as the
rotational speed and the torque of the cutting tool 100. Due to
this, it becomes possible to detect an irregular state such as
breakage of the cutting tool 100 in real time based on the
monitored various data. Further, it also becomes possible to easily
manage the time used for machining.
Further, the microprocessor 505 of the processing circuit part 504
monitors the state of the generator 70 and the electric motor 80.
When an irregular state occurs, it transmits this irregular state
information to the management apparatus 400. When obtaining the
irregular state information, the management apparatus 400 transmits
this irregular state information to the numerical control apparatus
51. When the irregular state information is transmitted, the
numerical control apparatus 51 controls the automatic tool changer
39 so as to detach the tool 260 from the spindle 46.
As described above, according to the present embodiment, by
providing a program for controlling the tool 260 in the processing
circuit part 504, it becomes possible to control the tool 260
separately from the spindle 46.
Further, by transmitting a program from the management apparatus
400 to the tool 260 and transmitting not only the simple tool
information but various state information while machining to the
management apparatus 400, it becomes possible to precisely manage
the tool 260.
While the invention has been described by the reference to specific
embodiments chosen for purpose of illustration, it should be
apparent that numerous modification could be made thereto by those
skilled in the art without departing from the basic concept and
scope of the invention.
For example, in the above embodiments, the explanation was given
with reference to a cutting tool 100 as a machining tool, but the
present invention can also be applied to other machining tools such
as a grinding wheel, a polishing tool, or the like.
* * * * *