FORM 2
THE PATENT ACT 1970 (39 of 1970)
&
The Patents Rules, 2003 COMPLETE SPECIFICATION (See Section 10, and rule 13)
1. TITLE OF INVENTION MACHINE TOOL
2. APPLICANT(S)
a) Name : MITSUBISHI HEAVY INDUSTRIES, LTD.
b) Nationality : JAPANESE Company
c) Address : 16-5, KONAN 2-CHOME,
MINATO-KU, TOKYO 1088215, JAPAN
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

TECHNICAL HELD
The present invention relates to a machine tool that machines a machining subject by moving the machining subject and a tool relative to each other.
BACKGROUND ART
In machine tools such as a machining center, a workpiece is machined by moving a tool detachably mounted on a main spindle and the workpiece attached to a table, relative to each other. Among such machine tools, there is provided a machine tool having a turning mechanism, a rotation mechanism, and the like in addition to a moving mechanism so that the degree of freedom of a machining posture of the mounted tool can be increased. Specifically, the turning mechanism turns the main spindle in a way that the main spindle faces in multiple directions. The rotation mechanism rotates a workpiece in multiple directions. The moving mechanism moves the main spindle and the workpiece relative to each other in three orthogonal-axis directions.
Thereby, multi-face machining can be performed on the workpiece. Such a conventional machine tool is disclosed in Patent Document 1, for example.
Patent Document 1: Japanese Patent Application Publication No. 2001-287102
DISCLOSURE OF THE INVENTION
PROBLEMS TO BE SOLVED BY THE INVENTION
However, when a long workpiece is machined by using the aforementioned conventional machine tool, the workpiece swing becomes large. This leads to increase in size of the machine accordingly. In addition, a horizontal machine tool in particular requires the tool length to be set long so that mutual interference of machine structures can be avoided, depending on the position at which an oblique

hole or the like is machined. This not only lowers the stiffness of the tool but also leads to increase in set-up changes. Consequently, the machining efficiency may be deteriorated.
Thus, the present invention has been made to solve the above problems. An object of the present invention is to provide a machine tool capable of performing multi-face machining on a long machining subject efficiently in a saved space.
MEANS FOR SOLVING THE PROBLEMS
A machine tool according to a first invention to solve the above problems is
characterized by comprising:
a main spindle on which a tool for machining a machining subject is detachably
mounted;
main-spindle turning means for turning the main spindle around a turning axis
orthogonal to an axis of the main spindle; and
machining-subject rotating means for rotating the machining subject around a
workpiece rotation axis orthogonal to the axis of the main spindle and the turning
axis.
A machine tool according to a second invention to solve the above problems is characterized by further comprising main-spindle rotating means for rotating the main spindle, the machine tool characterized in that
the main-spindle rotating means and the main-spindle turning means are arranged coaxially or respectively on two axes orthogonal to each other.
A machine tool according to a third invention to solve the above problems is characterized in that the main-spindle turning means includes a turn shaft member which has an axis arranged on the turning axis and which rotatably supports the main spindle, and the main spindle and the main-spindle rotating means are connected to each other

inside the turn shaft member.
A machine tool according to a fourth invention to solve the above problems is characterized in that the main spindle is supported rotatably around a horizontal axis.
EFFECTS OF THE INVENTION
With the machine tool according to the present invention, the swing of a machining subject can be made smaller by turning the main spindle around the turning axis orthogonal to the axis of the main spindle and by rotating the machining subject around the workpiece rotation axis orthogonal to the axis of the main spindle and the turning axis. Accordingly, multi-face machining can be performed on a long machining subject efficiently in a saved space.
BRIEF DESCRIPTION OF THE DRAWINGS
[Fig. 1] Fig. 1 is a schematic perspective view of a machine tool according to an
embodiment of the present invention. [Fig. 2] Fig. 2 is an enlarged view of a saddle.
[Fig. 3] Fig. 3 is a cross-sectional view as viewed from III-III arrows in Fig. 2. [Fig. 4] Fig. 4 is a view illustrating how a workpiece disposed at a middle
machining position is machined. Part (a) of Fig. 4 is a plan view, and Part
(b) of Fig. 4 is a side view. [Fig. 5] Fig. 5 is a view illustrating how the workpiece disposed at a top
machining position is machined. Part (a) of Fig. 5 is a plan view, and Part
(b) of Fig. 5 is a side view. [Fig. 6] Fig. 6 is a view illustrating how the workpiece disposed at a bottom
machining position is machined. Part (a) of Fig. 6 is a plan view, and Part
(b) of Fig. 6 is a side view.

BEST MODE FOR CARRYING OUT THE INVENTION
Hereinbelow, a machine tool according to the present invention will be described in detail with reference to the drawings. Fig. 1 is a schematic perspective view of the machine tool according to an embodiment of the present invention. Fig. 2 is an enlarged view of a saddle. Fig. 3 is a cross-sectional view as viewed from III-III arrows in Fig. 2. Fig. 4 is a view illustrating how a workpiece disposed at a middle machining position is machined. Part (a) of Fig. 4 is a plan view, and Part (b) of Fig.
4 is a side view. Fig. 5 is a view illustrating how the workpiece disposed at a top machining position is machined. Part (a) of Fig. 5 is a plan view, and Part (b) of Fig.
5 is a side view. Fig. 6 is a view illustrating how the workpiece disposed at a bottom machining position is machined. Part (a) of Fig. 6 is a plan view, and Part (b) of Fig. 6 is a side view. Note that an X-axis direction, Y-axis direction and Z-axis direction described in the drawings indicate three orthogonal-axis directions which are orthogonal to each other.
As shown in Fig. 1, a machine tool 1 includes a bed 11. Paired right and left guide rails 12a, 12b extending in the Z-axis direction are provided on an upper surface of the bed 11. A column 13 is supported slidably in the Z-axis direction by the guide rails 12a, 12b. Accordingly, the column 13 becomes movable in the Z-axis direction by driving column driving means formed of a column drive motor, a column-feeding threaded mechanism and the like which are not illustrated.
Paired right and left guide rails 14a, 14b extending in the Y-axis direction are formed on a front surface of the column 13. A saddle 15 is supported slidably in the Y-axis direction by the guide rails 14a, 14b. Accordingly, the saddle 15 becomes movable in the Y-axis direction by driving saddle driving means formed of a saddle drive motor, a saddle-feeding threaded mechanism and the like which are not illustrated.
In addition, paired right and left guide rails 16a, 16b extending in the X-axis direction are formed near end portions of the guide rails 12a, 12b on the upper

surface of the bed 11. A table base 17 is supported slidably in the X-axis direction by the guide rails 16a, 16b. Furthermore, paired right and left table support plates 18 stand on an upper surface of the table base 17. Besides, a rotary table 19 is rotatably supported between ends of these table support plates 18. A long workpiece W is detachably attached to the rotary table 19 with an attachment jig 20 located in between.
Accordingly, the rotary table 19 rotatably supported by the table base 17 with the table support plates 18 located in between becomes movable in the X-axis direction by driving table driving means formed by a table drive motor, a table-feeding threaded mechanism and the like which are not illustrated. Furthermore, the rotary table 19 becomes rotatable around a horizontal axis (workpiece rotation axis) by driving table rotating means (machining-subject rotating means) formed of an unillustrated table rotating motor and the like.
Next, a configuration of the saddle 15 will be described by using Fig. 2 and Fig. 3.
As shown in Fig. 2 and Fig. 3, an end portion of the saddle 15 has a substantially cylindrical shape. A tubular hollow portion 31 is formed inside the end portion. The hollow portion 31 is formed of small-diameter hollow portions 31a and a large-diameter hollow portion 31b. The large-diameter hollow portion 31b has a larger inner diameter than the inner diameter of each of the small-diameter hollow portions 31a, and is formed in a middle portion of the hollow portion 31 in an axial direction thereof. In addition, an opening portion 31c opened at a front surface of the saddle 15 is formed on an end portion side of the large-diameter hollow portion 31b.
A cylindrical turn shaft member 41 is rotatably supported in the hollow portion 31. The turn shaft member 41 is formed of small-diameter shaft portions 41a and a large-diameter shaft portion 41b. The large-diameter shaft portion 41b has a larger outer diameter than the outer diameter of each of the small-diameter shaft portions

41a, and is formed in the middle portion, in the axial direction, of the turn shaft member 41. In addition, each small-diameter shaft portion 41a of the turn shaft member 41 is rotatably supported in the small-diameter hollow portion 31a of the hollow portion 31 with a bearing 42. Turn drive motors 43 are each provided between the small-diameter hollow portion 31a and the small-diameter shaft portion 41a. These turn drive motors 43 are each formed of a stator 43a fixed to an inner circumferential surface of the small-diameter portion 31a, and a rotor 43b fixed to an outer circumferential surface of the small-diameter shaft portion 41a. In contrast, the large-diameter shaft portion 41b of the turn shaft member 41 is arranged in the large-diameter hollow portion 31b of the hollow portion 31 in such a manner that a side of the large-diameter shaft portion 41b faces the opening portion 31c. A main spindle 45 is rotatably supported in the large-diameter shaft portion 41b with a bearing 44. A tool T is detachably mounted on an end of the main spindle 45.
An annular member 46 of an annular shape is provided outward of an upper end of one of the small-diameter shaft portions 41a of the turn shaft member 41, while a disk member 47 of a disk shape is provided outward of a lower end of the other small-diameter shaft portion 41a. In addition, a main spindle motor 48 is provided on an upper end of the small-diameter shaft portion 41a and on an upper surface of the annular member 46. An output shaft 49 of the main spindle motor 48 is inserted in the small-diameter shaft portion 41a and the large-diameter shaft portion 41b. Furthermore, a bevel gear 49a is formed at an end of the output shaft 49. The bevel gear 49a meshes with a bevel gear 45a formed around an outer circumferential surface of the main spindle 45.
Specifically, when the main spindle motor 48 is driven, a driving force thereof is thereby transmitted from the bevel gear 49a of the output shaft 49 to the bevel gear 45a of the main spindle 45. Consequently, the tool T is driven and rotated around a horizontal axis together with the main spindle 45. Meanwhile, when the turn drive motors 43 are driven and thus the rotors 43b at the inner side thereof are rotated relative to the stators 43a at the outer side thereof. The turn shaft member 41 is

thereby rotated around a vertical axis (turning axis) relative to the hollow portion 31 of the saddle 15. Consequently, the tool T is driven and turned together with the main spindle 45 supported in the large-diameter shaft portion 41b of the turn shaft member 41. At this point, since the main spindle motor 48 is fixed to the small-diameter shaft portion 41a of the turn shaft member 41, the main spindle motor 48 is simultaneously rotated around the vertical axis when the turn shaft member 41 is rotated (turned). Thereby, a driving force from the output shaft 49 is appropriately transmitted to the main spindle 45 via the bevel gears 45a, 49a.
Note that the hollow portion 31, the rum shaft member 41, the turn drive motors 43, the main spindle motor 48 and the output shaft 49 are coaxially arranged. In addition, the hollow portion 31, the turn shaft member 41, the turn drive motors 43 and the like constitute main-spindle turning means. Besides, the table support plates 18, the rotary table 19 and the like constitute machining-subject rotating means. Furthermore, the turn shaft member 41, the main spindle 45, the main spindle motor 48, the output shaft 49 and the like constitute main-spindle rotating means. Meanwhile, the main spindle motor 48 is provided coaxially with the turn drive motor 43 in this embodiment, but may be provided coaxially with the main spindle 45.
Accordingly, when five-face machining is performed on the workpiece W, the rotary table 19 is firstly indexed and rotated around the horizontal axis in such a manner that the attachment jig 20 is disposed at an uppermost position thereof. Then, in this state, the workpiece W is attached to the attachment jig 20 (see Part (b) of Fig. 5).
Subsequently, as shown in Parts (a) and (b) of Fig. 4, the rotary table 19 is indexed
and rotated, and the workpiece W is disposed at a middle machining position PI in
such a manner as to face the column 13 (saddle 15). Thereafter, while the tool T is
rotated by driving the main spindle motor 48, the column 13 is moved in the Z-axis
direction, the saddle 15 is moved in the Y-axis direction, the tool T is turned around
the vertical axis by the turn drive motors 43, and the rotary table 19 is moved in the
8

X-axis direction. Thereby, the tool T is moved as shown by two-dot chain lines in Part (a) of Fig. 4. Consequently, machining is performed on end faces Wa, Wd, We of the workpiece W disposed at the middle machining position PI. Note that end faces Wb, Wc of the workpiece W can be machined depending on the shape of the tool T.
Then, as shown in Parts (a) and (b) of Fig. 5, the rotary table 19 is indexed and rotated, and the workpiece W is disposed at a top machining position P2 which is an uppermost position. Thereafter, while the tool T is rotated by driving the main spindle motor 48, the column 13 is moved in the Z-axis direction, the saddle 15 is moved in the Y-axis direction, the tool T is turned around the vertical axis by the turn drive motors 43, and the rotary table 19 is moved in the X-axis direction. Thereby, the tool T is moved as shown by two-dot chain lines in Part (a) of Fig. 5. Consequently, machining is performed on the end faces Wc, Wd, We of the workpiece W disposed at the top machining position P2. Note that the end face Wa of the workpiece W can be machined depending on the shape of the tool T.
Thereafter, as shown in Parts (a) and (b) of Fig. 6, the rotary table 19 is indexed and rotated, and the workpiece W is disposed at a bottom machining position P3 which is a lowermost position. Then, while the tool T is rotated by driving the main spindle motor 48, the column 13 is moved in the Z-axis direction, the saddle 15 is moved in the Y-axis direction, the tool T is turned around the vertical axis by the turn drive motors 43, and the rotary table 19 is moved in the X-axis direction. Thereby, the tool T is moved as shown by two-dot chain lines in Part (a) of Fig. 6. Consequently, machining is performed on the end faces Wb, Wd, We of the workpiece W disposed at the bottom machining position P3. Note that the end face Wa of the workpiece W can be machined depending on the shape of the tool T.
In addition, if necessary, the workpiece W is disposed at any angle regardless of the machining positions PI, P2 and P3, and machined until the workpiece W is machined to have a predetermined shape.

Accordingly, with the machine tool according to the present invention, the workpiece W is rotated around the horizontal axis orthogonal to the axis of the main spindle 45 and the vertical axis, while the main spindle 45 is turned around the vertical axis orthogonal to the axis of the main spindle 45. This can make smaller the swing of the workpiece W. Accordingly, multi-face machining can be performed on the long workpiece W efficiently in a saved space. In addition, coaxial arrangement of the turn drive motor 43 and the main spindle motor 48 enables a simple configuration, thus achieving reduction in size of the machine tool.
Furthermore, since the distance between the end of the main spindle 45 and the workpiece W can be reduced while the tool T is in any posture, it is possible to reduce the tool length and thus enhance the stiffness of the tool T. Besides, since the machine tool 1 is of a horizontal type in which the tool T is rotated around the horizontal axis, chips are not deposited on the workpiece W. Accordingly, the life of the tool can be increased.
INDUSTRIAL APPLICABILITY
The present invention is applicable to a machine tool capable of machining a long workpiece in a short time.

WE CLAIM:
1] A machine tool characterized by comprising:
a main spindle on which a tool for machining a machining subject is
detachably mounted;
main-spindle turning means for turning the main spindle around a turning
axis orthogonal to an axis of the main spindle; and
machining-subject rotating means for rotating the machining subject around
a workpiece rotation axis orthogonal to the axis of the main spindle and the
turning axis.
2] The machine tool according to claim 1, characterized by further comprising
main-spindle rotating means for rotating the main spindle, the machine tool characterized in that
the main-spindle rotating means and the main-spindle turning means are arranged coaxially or respectively on two axes orthogonal to each other.
3] The machine tool according to claim 2, characterized in that the main-spindle
turning means includes a turn shaft member which has an axis arranged on the turning axis and which rotatably supports the main spindle, and the main spindle and the main-spindle rotating means are connected to each other inside the turn shaft member.
4] The machine tool according to any one of claims 1 to 3, characterized in that
the main spindle is supported rotatably around a horizontal axis.