TECHNICAL FIELD
[0001]
The present invention relates to a machine tool.
BACKGROUND ART
[0002]
In a machine tool, machining is performed on a workpiece
by using a program and the like, and tools used for machining
are replaced as appropriate depending on machined portions,
machining steps, and the like. Patent Document 1 and Patent
Document 2 can be given as examples of techniques related to
tool replacement in a machine tool.
[0003]
Patent Document 1 shows a tool replacement device as
follows. A clamping device configured to clamp a tool has an
inner peripheral face of a holding hole into which the tool is
inserted and by which an outer periphery of the tool is held,
and a wedge member is disposed to fit between the inner
peripheral face of the holding hole in the clamping device and
an outer peripheral face of the tool by rotation of the tool.
This tool replacement device can automatically replace tools
which are suitable for high speed rotation and which have smooth
outer peripheral faces without key grooves or the like.
Specifically, a device configured to mainly automatically
replace tools which have good rotational balance and which are
detachably attached to a main spindle of a high-speed machine
can be made suitable for high-speed rotation and have simple
and compact structure.
[0004]
2
Patent Document 2 is a technique related to a control
device for a device configured to easily perform coupling
between a draw bar and a tool, and shows a tool
attachment-detachment rotation control device which controls
a rotation drive unit configured to screw-couple the tool to
the fixed draw bar by rotating a tool holding portion holding
the tool. In this technique, since the rotation drive unit
screw-couples the tool to the fixed draw bar by rotating the
tool relative to the drawbar and the tool attachment-detachment
rotation control device appropriately controls the rotation
drive unit, coupling between the draw bar and the tool is very
easy.
PRIOR ART DOCUMENT
PATENT DOCUMENT
[0005]
Patent Document 1: Japanese Patent Application Publication No.
Hei 10-080836
Patent Document 2 : Japanese Patent Application Publication No.
2001-047336
SUMMARY OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
[0006]
However, in the clamping of the tool in Patent Document
1 and Patent Document 2 , screw portions are provided on the tool
side and the main spindle side, and the screw portions are
screw-coupled to each other. Accordingly, the diameters and
the lengths of the screws cannot be reduced in view of securing
coupling force between the tool side and the main spindle side.
In other words, it is difficult to reduce the sizes of portions
around the tool and the main spindle. Moreover, although the
3
automatic replacement of tools is achieved, time is required
for attaching and detaching of screw coupling because the tools
and the like are rotated. Accordingly, it is difficult to
improve the operating ratio of the machine tool.
[0007]
Moreover, in a machine tool capable of machining narrow
and small portions, automatic machining is performed by using
a program while replacement of tools used for machining is
manually performed by an operator. This is because limitations
are imposed on the sizes of portions and parts of the machine
tool for machining narrow and small portions to enable machining
of narrow and small portions. In other words, in the machine
tool capable of machining narrow and small portions, the size
of a mechanism for tool replacement particularly needs to be
reduced. However, even if the size of the mechanism for tool
replacement in the conventional machine tool is simply reduced,
the mechanism cannot be employed in the machine tool for
machining narrow and small portions.
[0008]
The present invention has been made in view of the problems
described above, and an object thereof is to simplify a
mechanism for tool replacement in a machine tool and reduce the
sizes of portions around a tool and a main spindle.
MEANS FOR SOLVING THE PROBLEMS
[0009]
A machine tool of a first aspect of the invention for
solving the problems described above is a machine tool in which
a tool unit having a tool used for machining is attached to a
main spindle via an attachment, characterized in that the
attachment has a cylinder portion fixed to the main spindle and
4
a piston portion slidably held by the cylinder portion, the
cylinder portion has a plurality of spherical bodies capable
of projecting in a radial direction of the cylinder portion,
the piston portion has an abutment face configured to cause the
spherical bodies to project in the radial direction of the
cylinder portion when the piston portion slides to one side
relative to the cylinder portion, and the tool unit has a
projection inclined face projecting in a radial direction of
the tool unit and is coupled to the attachment by the projection
inclined face being pressed against the spherical bodies caused
to project in the radial direction of the cylinder portion by
the sliding of the piston portion to the one side.
[0010]
A machine tool of a second aspect of the invention for
solving the problems described above is characterized in that
the piston portion has an escape hole which allows the steel
ball to move in the radial direction of the cylinder portion
and which is located at a position corresponding to each of the
steel balls when the piston slides to another side, the escape
hole, and in the tool unit, when the piston portion slides to
the other side relative to the cylinder portion, the escape hole
is set at the position corresponding to the steel ball and the
spherical body is set to become movable in the radial direction
of the cylinder portion, the tool unit thereby being released
from the spherical body and set to become detachable from the
attachment.
[0011]
A machine tool of a third aspect of the invention for
solving the problems described above is characterized in that
the attachment has : an elastic body which is provided such that
5
force causing the piston portion to slide to the one side acts
on the piston portion; and a fluid supply space to which fluid
is supplied such that force causing the piston portion to slide
to the other side acts on the piston portion, and the piston
portion slides to the other side by pressure of the fluid when
the fluid is supplied to the fluid supply space, and slides to
the one side due to elastic deformation of the elastic body when
the fluid is discharged from the fluid supply space.
[0012]
A machine tool of a fourth aspect of the invention for
solving the problems described above is characterized in that
the machine tool comprises a tool unit holding device configured
to assist in attaching and detaching of the tool unit and
transport the tool unit.
EFFECT OF THE INVENTION
[0013]
According to the machine tool of the first aspect of the
invention, since the tool unit is coupled to the attachment by
pressing the spherical bodies of the cylinder portion against
the projection inclined face of the tool unit by the sliding
of the piston portion toward the one side, the tool unit and
the attachment can be coupled to each other with predetermined
coupling force in a simple mechanism. Furthermore, since no
screw coupling is employed, the lengths and screw diameters of
screw coupling portions for obtaining predetermined coupling
force are unnecessary. Accordingly, the sizes of the tool unit
and attachment can be reduced. Moreover, since the tool unit
and the attachment can be attached to each other only by causing
the piston portion to slide to the one side relative to the
cylinder portion, work of rotating a member such as screw
6
coupling is not involved, and the attachment time can be
reduced.
[0014]
According to the machine tool of the second aspect of the
invention, since the tool unit is set to become detachable from
the attachment only by causing the piston portion to slide to
the other side relative to the cylinder portion, it is possible
to release the tool unit from the predetermined coupling force
and detach the tool unit from the attachment in a simple
mechanism. Moreover, since the detachment of the tool unit and
the attachment can be performed only by causing the piston
portion to slide to the other side relative to the cylinder
portion, work of rotating a member such as screw coupling is
not involved, and the detachment time can be reduced.
[0015]
According to the machine tool of the third aspect of the
invention, since the piston portion can be caused to slide to
the one side and the other side by supplying and discharging
the fluid to and from the fluid supply space, the mechanism for
attaching and detaching the tool unit and the attachment can
have a simple structure, and the attaching and detaching of the
tool unit to and from the attachment can be facilitated.
[0016]
According to the machine tool of the fourth aspect of the
invention, since the attaching and detaching of the tool unit
to and from the attachment can be automatically performed by
causing the tool unit holding device to transport the tool unit
and assist in the attaching and detaching of the tool unit to
and from the attachment, the tool can be automatically replaced.
BRIEF DESCRIPTION OF THE DRAWINGS
7
[0017]
[Fig. 1] Fig. 1 is a vertical cross-sectional view showing
portions around a tool in a machine tool of Embodiment 1.
[Fig. 2] Fig. 2 is a perspective view showing the machine
tool of Embodiment 1.
[Fig. 3] Fig. 3 is an explanatory view showing a clamp
mechanism of a tool in the machine tool of Embodiment 1.
[Fig. 4] Fig. 4 is an explanatory view showing the clamp
mechanism of the tool in the machine tool of Embodiment 1.
[Fig. 5] Fig. 5 is an explanatory view showing the clamp
mechanism of the tool in the machine tool of Embodiment 1.
[Fig. 6] Fig. 6 is an explanatory view showing the clamp
mechanism of the tool in the machine tool of Embodiment 1.
[Fig. 7] Fig. 7 is an explanatory view showing tool
replacement in the machine tool of Embodiment 1.
[Fig. 8] Fig. 8 is a front view showing a tool unit holding
device in the machine tool of Embodiment 1.
MODE FOR CARRYING OUT THE INVENTION
[0018]
An embodiment of a machine tool in the present invention
is described below in detail with reference to the attached
drawings. As a matter of course, the present invention is not
limited to the embodiment described below, and various
modifications can be made within a scope not departing from the
spirit of the present invention.
EMBODIMENT 1
[0019]
First, the machine tool of the present invention is
described with reference to Figs. 1 to 8.
[0020]
8
The machine tool of the embodiment is a double-column
machining center capable of machining narrow and small portions .
As shown in Fig. 2, the machine tool includes a bed 1, a table
2 , a column 3 , a cross rail 4 , a saddle 5, a ram 6, a main spindle
7 included in the ram 6, and a tool unit 9 attached to the main
spindle 7 via an attachment 8.
[0021]
The bed 1 is horizontally installed under a floor, and
the table 2 and the column 3 are installed on the bed 1. The
table 2 is a stage on which a not-illustrated workpiece is placed
and can move in one direction on the bed 1. The cross rail 4
is installed on the vertically-installed gate-shaped column 3
and can move in a direction perpendicular to the column 3 . The
saddle 5 is installed on the cross rail 4 and can rotate and
move in an axial direction relative to the cross rail 4 to change
a position and direction of machining the workpiece. The ram
6 is held by the saddle 5 and can slide in an axial direction
relative to the saddle 5. The main spindle 7 is held by the
ram 6 and can be rotated by a not-illustrated drive device.
[0022]
The tool unit 9 is a unit which enables a tool 10 to be
attached to and detached from the attachment 8. As shown in
Fig. 1, the tool unit 9 includes the tool 10, a tool holder 20
configured to hold the tool 10, and a tool clamping member 40
attached to the tool holder 2 0 via a spacer 30. The tool unit
9 is coupled to the attachment 8 in the tool clamping member
40. A recess groove 21 is provided in the tool holder 20 to
facilitate attaching and detaching of the tool unit 9 to and
from the attachment 8 (details will be described later).
[0023]
9
The attachment 8 is used to attach the tool unit 9 to the
main spindle 7. As shown in Fig. 1, the attachment 8 includes
a cylinder 5 0 fixed to the main spindle 7, a cylinder head 6 0
fixed to the cylinder 50, and a piston 70 slidably supported
by the cylinder 50 and the cylinder head 60 . In the embodiment,
since a disc spring 80 is installed between the cylinder head
60 and the piston 70, predetermined force generated by elastic
deformation of the disc spring 80 always acts on the piston 70.
In other words, the piston 70 is always in a load state of being
moved toward one side (right side in Fig. 1) in an axial direction
where the cylinder 50 is installed.
[0024]
As a matter of course, the force acting on the piston 70
is not limited to the force generated by elastic deformation
of the disc spring 8 0 in the embodiment. For example, an elastic
body such as urethane rubber or the like may be installed to
cause force generated by elastic deformation of the urethane
rubber or the like to act on the piston 70. Alternatively, a
configuration may be employed in which a closed space is formed
between the cylinder head 60 and the piston 70 and fluid such
as hydraulic oil or the like is poured into the space to cause
hydraulic pressure or the like to act on the piston 70 . Moreover,
a configuration may be employed in which a coil spring or the
like is installed on one side of the piston 70 where the cylinder
50 is installed, and the piston 70 is pulled to the one side
due to elastic deformation of the coil spring or the like.
[0025]
Moreover, a pressure oil chamber 100 which is a closed
space is formed by installing a sealing member 90 between the
cylinder 50 and the piston 70. Hydraulic pressure is caused
10
to act on the piston 70 by supplying hydraulic pressure oil from
an oil feed port 51 formed in the cylinder 50 to the pressure
oil chamber 100 via an oil feed passage 52.
[0026]
Furthermore, an air feed port 53 is formed in the cylinder
50. Supplying air from the air feed port 53 in the attaching
and detaching of the attachment 8 and the tool unit 9 can cause
air to flow through an air feed passage 54 formed in the cylinder
5 0 and an air hole 62 (see Figs. 3 to 6) formed in the cylinder
head 60 and blow away dusts and the like between the cylinder
head 6 0 in the attachment 8 and the tool clamping member 4 0 in
the tool unit 9 configured to come into close contact with each
other.
[0027]
As shown in Figs. 3 and 6, a circular hole 61 is provided
in the cylinder head 60, and a steel ball 110 is provided in
the circular hole 61. Multiple circular holes 61 are provided
along a circumference of the cylinder head 60, and the steel
ball 110 is provided in each of the circular holes 61 in such
a way as not to fall out from the circular hole 61. The steel
ball 110 is held to be slightly movable only in a radial direction
of the cylinder head 60, and is held to be immovable in an axial
direction and a circumferential direction of the cylinder head
60.
[0028]
The piston 70 has an abutment face 71 for applying load
on the steel ball 110 by abutting on the steel ball 110 and an
escape hole 72 allowing movement of the steel ball 110 in the
radial direction of the cylinder head 60. The escape hole 72
is at a position corresponding to the steel ball 110 when the
11
piston 70 slides to the other side in the axial direction where
the tool unit 9 is attached.
[0029]
In a state where the tool unit 9 is attached to the main
spindle 7 via the attachment 8, as shown in Fig. 3, the steel
ball 110 held in the circular hole 61 of the cylinder head 60
is in contact with the abutment face 71 of the piston 70 and
a projection inclined face 41 obliquely projecting in a radial
direction of the tool clamping member 40. In other words, the
steel ball 110 is in a state pressed against the projection
inclined face 41 of the tool clamping member 4 0 by the abutment
face 71 of the piston 70 and the circular hole 61 of the cylinder
head 60. Accordingly, the tool unit 9 including the tool
clamping member 4 0 is not detached from the attachment 8
including the steel ball 110.
[0030]
Moreover, multiple contact portions between the
attachment 8 and the tool unit 9 are provided to stabilize
coupling between the attachment 8 and the tool unit 9.
Specifically, the cylinder head 60 in the attachment 8 and the
tool clamping member 4 0 in the tool unit 9 are in contact with
the each other via the steel ball 110 and are also in direct
contact with each other at a right-angle contact face 42 and
an inclined contact face 43 of the tool clamping member 40.
[0031]
The attachment angle of the tool unit 9 with respect to
the attachment 8 can be accurately and easily determined by
bringing the right-angle contact face 42 of the tool clamping
member 40 into contact with the cylinder head 60. Moreover,
it is possible to improve the stiffness in the axial direction
12
of the tool 10 in the machining of the not-illustrated workpiece
by the tool 10.
[0032]
The attachment angle of the tool unit 9 with respect to
the attachment 8 can be more accurately and easily determined
by brining the inclined contact face 43 of the tool clamping
member 4 0 into contact with the cylinder head 60. Moreover,
it is possible to improve the stiffness not only in the axial
direction of the tool 10 but also in the radial direction of
the tool 10 in the machining of the not-illustrated workpiece
by tool 10.
[0033]
Note that, in the attaching and detaching of the
attachment 8 and the tool unit 9, since dust and the like near
the right-angle contact face 42 and the inclined contact face
43 are blown away by spraying air from the air hole 62 provided
in the cylinder head 60, no dust or the like is caught on the
right-angle contact face 42 and the inclined contact face 43.
Accordingly, coupling of the attachment 8 and the tool unit 9
can be further stabilized.
[0034]
As a matter of course, the structures of the attachment
8 and the tool unit 9 are not limited to those in the embodiment.
For example, the abutment face 71 of the piston 70 may be formed
as an inclined face (inclined face in which the abutment face
71 extends downward toward the left in Fig. 3) projecting in
a radial direction such that the projection amount becomes
greater toward the tool unit 9. Forming the abutment face 71
of the piston 70 as the inclined face can cause the pressing
force by which the abutment face 71 of the piston 70 presses
13
the steel ball 110 against the projection inclined face 41 of
the tool clamping member 40 to increase as the piston 70 is moved
by the force of elastic deformation of the disc spring 80 toward
the one side (right side in Fig. 3) in the axial direction where
the cylinder 50 is installed. Accordingly, coupling force
between the tool unit 9 and the attachment 8 can be increased.
Moreover, the pressing force by which the abutment face 71 of
the piston 70 presses the steel ball 110 against the projection
inclined face 41 of the tool clamping member 4 0 can be increased
also by changing the type and the like of the disc spring 8 0
installed between the cylinder head 60 and the piston 70.
[0035]
In the attaching and detaching of the attachment 8 and
the tool unit 9, the hydraulic oil is introduced into the
pressure oil chamber 100 provided between the cylinder 50 and
the piston 70 to apply hydraulic pressure on the piston 70, the
hydraulic pressure being greater than the force generated by
elastic deformation of the disc spring 80. The piston 70 is
caused to slide by the hydraulic pressure toward the other side
in the axial direction where the tool unit 9 is attached, and
the escape hole 72 provided in the abutment face 71 of the piston
70 is set at the position corresponding to the steel ball 110
(see Fig. 4).
[0036]
In a case of detaching the tool unit 9 from the attachment
8, moving the tool unit 9 to the opposite side to the attachment
8 can cause the projection inclined face 41 of the tool clamping
member 4 0 to push away the steel ball 110 provided in the circular
hole 61 of the cylinder head 60 in the attachment 8. Part of
the steel ball 110 is thereby fitted into the escape hole 72
14
of the piston 70, and the tool unit 9 can be detached from the
attachment 8 (see Fig. 5) .
[0037]
In a case of attaching the tool unit 9 to the attachment
8, moving the tool unit 9 toward the attachment 8 can cause the
inclined contact face 43 of the tool clamping member 40 to push
away the steel ball 110 provided in the circular hole 61 of the
cylinder head 60 in the attachment 8. Part of the steel ball
110 is thereby fitted into the escape hole 72 of the piston 70,
and the tool unit 9 can be attached to the attachment 8 (see
Fig. 6).
[0038]
In the machine tool of the embodiment, the attaching and
detaching of the attachment 8 and the tool unit 9 is performed
by using an unclamping device 12 0 and a tool unit holding device
130.
[0039]
The unclamping device 120 is a device configured to supply
hydraulic oil and air required in the detaching of the tool unit
9 from the attachment 8. The unclamping device 120 includes
an oil feed port 121 configured to supply the hydraulic oil by
being connected to the oil feed port 51 of the cylinder 50, an
air feed port 122 configured to supply air by being connected
to the air feed port 53 of the cylinder 50 , and a wheeled platform
12 3 used for moving.
[0040]
The tool unit holding device 13 0 is a device configured
to support and hold the tool unit 9 detached from the attachment
8. As shown in Figs. 7 and 8, the tool unit holding device 13 0
includes an U-shaped claw portion 131 configured to be fitted
15
to the recess groove 21 of the tool holder 20, a key 132 used
for aligning of a phase in the holding of the tool unit 9, a
proximity sensor 133 configured to check whether the tool unit
9 is held, and a wheeled platform 134 used for moving. Note
that a tool supporting device 140 configured to support part
of the tool 10 in the tool unit 9 is preferably provided to
stabilize the holding of the tool unit 9.
[0041]
Next, automatic replacement of the tool in the machine
tool of the embodiment is described with reference to Figs. 1
to 7.
[0042]
In the machine tool of the embodiment, a not-illustrated
tool replacement space for replacement of the tool unit 9 is
provided in a movable area of the attachment 8, and the
replacement (attaching and detaching) of the tool unit 9 is
performed by moving the attachment 8 to a tool replacement
position in the tool replacement space.
[0043]
First, as shown in Fig. 7, the unclamping device 12 0 and
the tool unit holding device 13 0 are brought close to the main
spindle 7 located at the tool replacement position in the tool
replacement space, and the tool unit 9 is set to become
detachable from the attachment 8 by causing the unclamping
device 120 to feed oil and air.
[0044]
The oil feed port 121 of the unclamping device 120 brought
close to the attachment 8 is connected to the oil feed port 51
of the cylinder 50 in the attachment 8, and the air feed port
122 of the unclamping device 12 0 is connected to the air feed
16
port 53 of the cylinder 50 in the attachment 8.
[0045]
When the hydraulic oil is supplied from the unclamping
device 12 0 to the pressure oil chamber 100 in the attachment
8, hydraulic pressure is generated. This hydraulic pressure
is transmitted to the piston 70 in the attachment 8 as pressing
force, and the hydraulic oil is supplied to the pressure oil
chamber 10 0 until the hydraulic pressure exceeds the force
generated by elastic deformation of the disc spring 80.
Specifically, pressure stronger than the force generated by
elastic deformation of the disc spring 80 acts on the piston
70 due to the hydraulic pressure of the hydraulic oil supplied
from the unclamping device 12 0, and the piston 7 0 is moved along
the cylinder 5 0 and the cylinder head 6 0 to the other side where
the tool unit 9 is attached.
[0046]
As shown in Fig. 4, the movement of the piston 7 0 relative
to the cylinder 50 and the cylinder head 60 causes the escape
hole 72 of the piston 70 to be set at the position corresponding
to the steel ball 110 provided in the circular hole 61 of the
cylinder head 60.
[0047]
Next, the tool unit 9 is detached from the attachment 8
by the tool unit holding device 13 0.
[0048]
When the tool unit holding device 13 0 is moved in a
direction away from the attachment 8, the tool unit 9 can be
detached from the attachment 8 because the U-shaped claw portion
41 of the tool unit holding device 130 is caught in the recess
groove 21 of the tool holder 2 0 in the tool unit 9.
17
[0049]
At this time, the projection inclined face 41 of the tool
clamping member 4 0 pushes away the steel ball 110 provided in
the circular hole 61 of the cylinder head 6 0 in the attachment
8, and the steel ball 110 is thereby fitted into the escape hole
72 of the piston 70 (see Fig. 5) . Accordingly, there is nothing
(steel ball 110) pressing the tool unit 9 against the attachment
8, and the tool unit 9 can be detached.
[0050]
Next, the tool unit 9 detached from the attachment 8 and
the tool unit holding device 13 0 are moved to a not-illustrated
retreat space, and the new tool unit 9 and tool unit holding
device 13 0 are brought close to the attachment 8 located at the
tool replacement position in the tool replacement space.
[0051]
One tool unit 9 and one tool unit holding device 13 0
correspond to one tool 10. Specifically, the machine tool
includes various tools 10 adapting to various types of machining,
various tool units 9 to which the various tools 10 are attached,
and various tool unit holding devices 13 0 holding the various
tool units 9. These various tool units 9 and tool unit holding
devices 130 are arranged in the not-illustrated retreat space.
[0052]
Next, the new tool unit 9 held by the new tool unit holding
device 130 is attached to the attachment 8.
[0053]
The tool unit holding device 13 0 is moved in a direction
approaching the attachment 8 . Since the steel ball 110 provided
in the circular hole 61 of the cylinder head 60 is in a state
fitted into the escape hole 72 of the piston 70 (see Fig. 5) ,
18
the tool unit 9 can be moved to the attaching position in the
attachment 8 (see Fig. 6).
[0054]
At this time, air is supplied from the unclamping device
12 0 . The supplied air is sprayed from the air hole 62 and blown
on the right-angle contact face 42 and the inclined contact face
43 of the tool clamping member 40 in the tool unit 9. The
right-angle contact face 42 and the inclined contact face 43
of the tool clamping member 40 can be thereby cleaned with air.
Since the tool clamping member 40 and the cylinder head 60 are
closely attached to each other with no dust or the like
interposed therebetween, the degree of close attachment between
the tool unit 9 and the attachment 8 is improved. Moreover,
the tool unit 9 and the attachment 8 can be attached to each
other in an accurate attachment direction.
[0055]
Next, the feeding of oil by the unclamping device 12 0 is
stopped, and the hydraulic oil in the pressure oil chamber 100
in the attachment 8 is discharged. Absence of hydraulic oil
in the pressure oil chamber results in no hydraulic pressure
acting on the piston 70 . Accordingly, only the force generated
by elastic deformation of the disc spring 80 acts on the piston
70, and the piston 7 0 is moved to the one side where the cylinder
50 is installed (see Fig. 3).
[0056]
Moving the piston 70 relative to the cylinder 50 causes
the escape hole 72 to be set at a position not corresponding
to the steel ball 110 provided in the circular hole 61 of the
cylinder head 60. Specifically, the steel ball 110 pushed out
from the escape hole 72 of the piston 70 is supported by the
19
abutment face 71 of the piston 7 0 and pushed against the
projection inclined face 41 of the tool clamping member 40 in
the tool unit 9. The tool unit 9 is thereby pushed toward the
attachment 8 by the steel ball 110, and the attaching of the
tool unit 9 to the attachment 8 is completed.
INDUSTRIAL APPLICABILITY
[0057]
In the present invention, it is possible to reduce the
sizes of the tool unit and the attachment and perform automatic
replacement of the tools. Accordingly, the present invention
is suitable as a machine tool, particularly as a machine tool
for machining narrow and small portions.
EXPLANATIONS OF REFERENCE NUMERALS
[0058]
1 BED
2 TABLE
3 COLUMN
4 CROSS RAIL
5 SADDLE
6 RAM
7 MAIN SPINDLE
8 ATTACHMENT
9 TOOL UNIT
10 TOOL
2 0 TOOL HOLDER
21 RECESS GROOVE OF TOOL HOLDER
3 0 SPACER
4 0 TOOL CLAMPING MEMBER
41 PROJECTION INCLINED FACE OF TOOL CLAMPING MEMBER
4 2 RIGHT-ANGLE CONTACT FACE OF TOOL CLAMPING MEMBER
20
4 3 INCLINED CONTACT FACE OF TOOL CLAMPING MEMBER
5 0 CYLINDER
51 OIL FEED PORT OF CYLINDER
52 OIL FEED PASSAGE OF CYLINDER
53 AIR FEED PORT OF CYLINDER
54 AIR FEED PASSAGE OF CYLINDER
6 0 CYLINDER HEAD
61 CIRCULAR HOLE OF CYLINDER HEAD
62 AIR HOLE OF CYLINDER HEAD
7 0 PISTON
71 ABUTMENT FACE OF PISTON
72 ESCAPE HOLE OF PISTON
8 0 DISC SPRING
9 0 SEALING MEMBER
100 PRESSURE OIL CHAMBER
110 STEEL BALL
12 0 UNCLAMPING DEVICE
13 0 TOOL UNIT HOLDING DEVICE
14 0 TOOL SUPPORTING DEVICE
21
I/We Claim:
[Claim 1]
A machine tool in which a tool unit having a tool used
for machining is attached to a main spindle via an attachment,
characterized in that
the attachment has a cylinder portion fixed to the main
spindle and a piston portion slidably held by the cylinder
portion,
the cylinder portion has a plurality of spherical bodies
capable of projecting in a radial direction of the cylinder
portion,
the piston portion has an abutment face configured to
cause the spherical bodies to project in the radial direction
of the cylinder portion when the piston portion slides to one
side relative to the cylinder portion, and
the tool unit has a projection inclined face projecting
in a radial direction of the tool unit and is coupled to the
attachment by the projection inclined face being pressed
against the spherical bodies caused to project in the radial
direction of the cylinder portion by the sliding of the piston
portion to the one side.
[Claim 2]
The machine tool according to claim 1, characterized in
that
the piston portion has an escape hole which allows the
steel ball to move in the radial direction of the cylinder
portion and which is located at a position corresponding to each
of the steel balls when the piston slides to another side, and
in the tool unit, when the piston portion slides to the
other side relative to the cylinder portion, the escape hole
22
is set at the position corresponding to the steel ball and the
spherical body is set to become movable in the radial direction
of the cylinder portion, the tool unit thereby being released
from the spherical body and set to become detachable from the
attachment.
[Claim 3]
The machine tool according to claim 2, characterized in
that
the attachment has : an elastic body which is provided such
that force causing the piston portion to slide to the one side
acts on the piston portion; and a fluid supply space to which
fluid is supplied such that force causing the piston portion
to slide to the other side acts on the piston portion, and
the piston portion slides to the other side by pressure
of the fluid when the fluid is supplied to the fluid supply space,
and slides to the one side due to elastic deformation of the
elastic body when the fluid is discharged from the fluid supply
space.
[Claim 4]
The machine tool according to claim 2 or 3, characterized
in that the machine tool further comprises a tool unit holding
device configured to assist in attaching and detaching of the
tool unit and transport the tool unit.