Machine tool

Abstract

A machine tool 1 includes tool holding parts 31 and 32 that hold tools 21 and 22, a first main shaft 11 that grips a workpiece W and is capable of rotating the gripped workpiece W in a first rotation state which enables lathe-turning along a first direction of the workpiece, a second main shaft 12 that grips the workpiece W and is capable of rotating the gripped workpiece W in a second rotation state which, different to the first rotation state, enables lathe-turning along an extending direction in a second direction of the workpiece different from the first direction, and a control part 16 that controls the first main shaft 11, the second main shaft 12, and tool holding parts so that the workpiece W is lathe-turned by the tools 21 and 22 held by a tool holding part 15.

Description

machine tool

[0001] The present disclosure relates to machine tools.

[0002] There is known a machine tool having a spindle that rotates a gripped workpiece and a tool spindle that moves in each direction of three orthogonal axes and rotates the gripped workpiece around a predetermined axis that is orthogonal to the spindle to turn the workpiece (see, for example, Japanese Patent No. 5442195).The machine tool described in Japanese Patent No. 5442195 has a tool spindle that rotates a tool around a predetermined axis that is orthogonal to the spindle, and thereby enables workpiece machining, including back surface machining, to be achieved at low cost and with a small device configuration.

[0003] However, the machine tool described in Patent Publication No. 5442195 turns the workpiece by gripping one end of the workpiece with the spindle and the other end of the workpiece with the tool spindle, so it is not easy to turn the workpiece by rotating it in a different direction.

[0004] The present disclosure is intended to solve such problems, and aims to provide a machine tool that can turn a gripped workpiece by rotating the workpiece in different rotation directions.

[0005] The machine tool according to the present disclosure includes a tool holding unit that holds a tool, a first spindle that grips a workpiece and is rotatable in a first rotational state that enables turning of the gripped workpiece along a first direction of the workpiece, a second spindle that grips the workpiece and is rotatable in a second rotational state that enables turning of the gripped workpiece along a second direction of the workpiece that is different from the first direction, and a control unit that controls the first spindle, the second spindle, and the tool holding unit so as to turn the workpiece using the tool held by the tool holding unit.

[0006] Furthermore, in the machine tool according to the present disclosure, in the first rotation state, it is preferable that the workpiece gripped by the first spindle rotates around the first rotation axis, and in the second rotation state, the workpiece gripped by the second spindle rotates around the second rotation axis having an extension direction different from that of the first rotation axis.

[0007] Furthermore, in the machine tool according to the present disclosure, it is preferable that the first spindle grips a first gripping portion which is one end of the workpiece, the second spindle grips a second gripping portion different from the first gripping portion, the first rotating shaft extends from the first gripping portion toward the other end of the workpiece, and the second rotating shaft extends from the second gripping portion in a direction different from the extension direction of the first rotating shaft.

[0008] Furthermore, in the machine tool according to the present disclosure, it is preferable that the control unit causes the first spindle to grip the workpiece, and in the first rotation state, causes the workpiece gripped by the first spindle to be turned using the tool held by the tool holding unit, causes the workpiece turned in the first rotation state to be gripped by the second spindle, and in the second rotation state, causes the workpiece gripped by the second spindle to be turned using the tool held by the tool holding unit.

[0009] In addition, it is preferable that the machine tool according to the present disclosure further includes a third spindle arranged opposite the first spindle, capable of gripping a workpiece and rotating the gripped workpiece around a third rotation axis extending parallel to the first rotation axis.

[0010] In addition, it is preferable that the machine tool according to the present disclosure further includes a fourth spindle arranged opposite the second spindle, capable of gripping a workpiece and rotating the gripped workpiece around a fourth rotation axis extending parallel to the second rotation axis.

[0011] In addition, in the machine tool according to the present disclosure, it is preferable that the first rotation axis extends in a direction perpendicular to the extension direction of the second rotation axis.

[0012] In the machine tool according to the present disclosure, the first spindle is preferably arranged on a different plane from the second spindle.

[0013] In the machine tool according to the present disclosure, the first spindle is preferably arranged on a different plane from the second spindle.

[0014] In the machine tool according to the present disclosure, the first spindle and the second spindle are preferably arranged on the same plane.

[0015] The machine tool according to the present disclosure can turn a gripped workpiece by rotating the workpiece in different rotational directions.

[0016] Fig. 1 is a schematic diagram of a machine tool according to an embodiment. Fig. 2 is a diagram showing a turning process of a workpiece executed by the machine tool 1 shown in Fig. 1, where (a) shows a first step, (b) shows a second step, (c) shows a third step, (d) shows a fourth step, (e) shows a fifth step, (f) shows a sixth step, (g) shows a seventh step, and (h) shows an eighth step. Fig. 3 is a schematic diagram of a machine tool according to a first modified example. Fig. 4 is a schematic diagram of a machine tool according to a second modified example. Fig. 5 is a schematic diagram of a machine tool according to a third modified example.

[0017] Hereinafter, a machine tool according to the present disclosure will be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to the embodiments, but extends to the inventions described in the claims and their equivalents.

[0018] FIG. 1 is a schematic diagram of a machine tool according to an embodiment.

[0019] The machine tool 1 has a bed 10, a first spindle 11, a second spindle 12, and an NC device 15. The machine tool 1 machines a workpiece held by either the first spindle 11 or the second spindle 12, which are arranged in an L-shape, using a first tool 21 held by a first tool rest 31, also referred to as a tool holder, and a second tool 22 held by a second tool rest 32. When the workpiece is held by the first spindle 11, the machine tool 1 machines the workpiece using the first tool 21, and when the workpiece is held by the second spindle 12, the machine tool 1 machines the workpiece using the second tool 22. The upper surface of the bed 10, which is also called the guide surface, is mounted with the first spindle 11, the second spindle 12, and the first tool rest 31 and the second tool rest 32 that hold the first tool 21 and the second tool 22, and the bed 10, the first spindle 11, the second spindle 12, and the first tool rest 31 and the second tool rest 32 are housed in a housing not shown.

[0020] The first spindle 11, also referred to as the front spindle, has a first chuck 11a that grips the workpiece with a first gripping portion, which is one end of the workpiece in the first direction that is parallel to the Z direction, and is placed on the bed 10 so as to be movable along the Z direction. The first spindle 11 rotates about a first rotation axis A1 that extends parallel to the Z direction, thereby rotating the workpiece gripped by the first chuck 11a in a first rotation state in which the workpiece rotates about the first rotation axis A1. In the first rotation state, the first spindle 11 rotates so as to be able to turn the workpiece gripped by the first chuck 11a along the extension direction of the first rotation axis A1, i.e., the first direction of the workpiece. The first chuck 11a is, for example, a two-jaw chuck controlled by compressed air.

[0021] The second spindle 12 has a second chuck 12a that holds a workpiece with a second gripper in the X direction, which is perpendicular to the Z direction. The second spindle 12 is mounted on the bed 10 so as to be movable along the X direction. The second rotation axis A2 of the second spindle 12 extends in the X direction and is shifted 90 degrees from the extension direction of the first rotation axis A1 of the first spindle 11, which extends in the Z direction. The second rotation axis A2 is located on the same plane as the first rotation axis A1. When the central axes of the first rotation axis A1 and the second rotation axis A2 intersect, the second rotation axis A2 is located on the same plane as the first rotation axis A1. When the central axes of the first rotation axis A1 and the second rotation axis A2 do not intersect, the second rotation axis A2 is located on a different plane from the first rotation axis A1. The second spindle 12 rotates about a second rotation axis A2 extending in the X direction on the same plane as the first rotation axis A1, thereby rotating the workpiece held by the second chuck 12a in a second rotation state around the second rotation axis A2. In the second rotation state, the second spindle 12 rotates so as to turn the workpiece held by the second chuck 12a along the extension direction of the second rotation axis A2, also referred to as the second direction of the workpiece. The second chuck 12a is, for example, a two-jaw chuck controlled by compressed air, similar to the first chuck 11a. The extension direction of the second rotation axis A2 is shifted 90 degrees from the first direction of the workpiece, and the second direction of the workpiece is shifted 90 degrees from the extension direction of the first rotation axis A1.

[0022] The NC device 15, also referred to as a control unit, has a central processing unit (CPU) and peripheral devices such as memory, and controls the rotation of the first spindle 11 and the second spindle 12, as well as the movement of the first spindle 11, the second spindle 12, and the first tool post 31 and the second tool post 32.

[0023] 2A to 2H are diagrams showing the turning process of a workpiece executed by machine tool 1, and Figures 2A to 2H show steps 1 to 8, respectively. In the turning process shown in Figure 2, machine tool 1 performs turning on the workpiece, but the machine tool according to the embodiment may perform cutting processes other than turning on the workpiece.

[0024] First, in the first step, the NC device 15 causes the first chuck 11a of the first spindle 11 to grip the workpiece W. While the first step is being performed, the NC device 15 retracts the second spindle 12 to a region where it does not interfere with the first chuck 11a gripping the workpiece W. The NC device 15 transports the workpiece W, for example, using a workpiece transport device (not shown), moves the workpiece W to a gripping position for the first chuck 11a, and applies a gripping force to the first chuck 11a to grip the workpiece W in the first chuck 11a. The workpiece W is a chuck workpiece having a rectangular parallelepiped shape, and the first chuck 11a grips a first gripping portion G1, which is one end of the workpiece W in the Z direction. Note that while the workpiece W has a rectangular parallelepiped shape, i.e., a square timber shape, it is preferable that the machine tool 1 have a near-shape shape that is close to the shape of the product to be formed by the turning process.

[0025] Next, in a second step, the NC device 15 starts a first turning process to turn the workpiece W held in the first chuck 11a. While the second step is being performed, the NC device 15 retracts the second spindle 12 to a region where it does not interfere with the first turning process. The NC device 15 rotates around a first rotation axis A1 extending in the Z direction, thereby rotating the workpiece W held in the first chuck 11a in a first rotation state around the first rotation axis A1. The NC device 15 also moves the first tool rest 31 holding the first tool 21 relatively to the first chuck 11a, thereby pressing the first tool 21 held by the first tool rest 31 against the workpiece W. The first tool 21 is positioned so that it can be turned in the X direction, i.e., a direction perpendicular to the first rotation axis A1. Pressing the first tool 21 against the rotating workpiece W turns the workpiece W, forming a first protrusion W1 on the workpiece W. The first protrusion W1 is formed in a cylindrical shape extending parallel to the Z direction at the end of the workpiece W opposite the first gripping portion G1.

[0026] Next, in a third step, the NC device 15 completes the first turning process of turning the workpiece W held by the first chuck 11a. The NC device 15 stops the rotation of the workpiece W held by the first chuck 11a by stopping the rotation of the first spindle 11. The NC device 15 also moves the first tool rest 31 holding the first tool 21 relatively to the workpiece W, thereby moving the first tool 21 pressed against the workpiece W to a position separated from the workpiece W.

[0027] Next, in a fourth step, the NC device 15 causes the second chuck 12a of the second spindle 12 to grip the workpiece W. The NC device 15 moves the second spindle 12 and applies a gripping force to the second chuck 12a, causing the second chuck 12a to grip the workpiece W. The workpiece W is gripped by both the first chuck 11a and the second chuck 12a. The second chuck 12a grips a second gripping portion G2 located between a first gripping portion G1, which is one end of the workpiece W, and the other end of the workpiece W. The workpiece W is gripped by the first chuck 11a from the Z direction and by the second chuck 12a from the X direction.

[0028] Next, in a fifth step, the NC device 15 releases the grip of the workpiece W by the first chuck 11a of the first spindle 11. The NC device 15 ends the grip of the workpiece W by the first chuck 11a and moves the first spindle 11 to release the grip of the workpiece W by the first chuck 11a of the first spindle 11. Note that in the fifth step, the NC device 15 may perform a cut-off process on the end of the workpiece W opposite to the first protrusion W1 of the workpiece W gripped by the second chuck 12a using a cut-off tool (not shown), thereby releasing the grip of the workpiece W by the first chuck 11a of the first spindle 11.

[0029] Next, in step 6, the NC device 15 starts a second turning process to turn the workpiece W held in the second chuck 12a. While step 6 is being performed, the NC device 15 retracts the first spindle 11 to a region where it does not interfere with the second turning process. The NC device 15 rotates the workpiece W held in the second chuck 12a around a second rotation axis A2 extending in the X direction, thereby rotating the workpiece W held in the second chuck 12a in a second rotational state around the second rotation axis A2. The extension direction of the second rotation axis A2 is different from the extension direction of the first rotation axis A1. The NC device 15 also moves the second tool rest 32, which holds the second tool 22, relatively to the second tool rest 32, thereby pressing the second tool 22 held by the second tool rest 32 against the workpiece W. The second tool 22 is positioned so that it can be turned in the Z direction, i.e., a direction perpendicular to the second rotation axis A2. The second tool 22 is pressed against the rotating workpiece W, thereby turning the workpiece W and forming a second protrusion W2 on the workpiece W. The second protrusion W2 is formed in a cylindrical shape extending parallel to the X direction on the end of the workpiece W opposite the second gripping portion G2.

[0030] Next, in a seventh step, the NC device 15 completes the second turning process of turning the workpiece W held by the second chuck 12a. The NC device 15 stops the rotation of the workpiece W held by the second chuck 12a by stopping the rotation of the second spindle 12. In addition, the second tool rest 32 holding the second tool 22 is moved relatively to the second tool rest 32, thereby moving the second tool 22 pressed against the workpiece W to a position separated from the workpiece W.

[0031] Then, in an eighth step, the NC device 15 releases the grip of the workpiece W by the second chuck 12a of the second spindle 12, thereby completing the turning process. The NC device 15 ends the grip of the workpiece W by the second chuck 12a, and transports the workpiece W using a work transport device (not shown), moving the workpiece W from the gripping position of the second chuck 12a, and releasing the grip of the workpiece W by the second chuck 12a.

[0032] The turning process shown in Fig. 2 is one example of a turning process, and the machine tool 1 can perform turning processes other than the turning process shown in Fig. 2. For example, the machine tool 1 may perform the turning process using only one of the first spindle 11 and the second spindle 12.

[0033] (Actions and Effects of Machine Tool According to the Embodiment) The machine tool 1 has the second spindle 12 that rotates the workpiece W in a second rotation state that can turn the workpiece W in a direction perpendicular to the first rotation state in which the first spindle 11 rotates the workpiece W, so that turning of the workpiece can be performed along two perpendicular directions. Because the machine tool 1 can turn the workpiece along two perpendicular directions, it can form parts made of irregularly shaped materials.

[0034] Furthermore, in the first rotation state, the machine tool 1 turns the workpiece W held by the first spindle 11 with the first tool 21, and then causes the second spindle 12 to grip the workpiece W turned in the first rotation state. Next, in the second rotation state, the machine tool 1 turns the workpiece W held by the second spindle 12 with the second tool 22, thereby processing a part made of a special shaped material. Because the machine tool 1 grips the workpiece W turned in the first rotation state with the second spindle 12 and turns it in the second rotation state, it is possible to form a part made of a special shaped material in a series of processes, and the manufacturing time for manufacturing parts made of special shaped material can be shortened.

[0035] Furthermore, in machine tool 1, first spindle 11 rotates the workpiece W in a first rotation state that allows turning along a first direction, and second spindle 12 rotates the workpiece in a second rotation state that allows turning along a second direction different from the first direction. Because machine tool 1 grips the workpiece so that first spindle 11 and second spindle 12 can turn in different directions, it is possible to manufacture irregularly shaped parts having distinctive shapes, such as parts with protrusions in different directions, in a relatively short manufacturing time. By manufacturing irregularly shaped parts in a relatively short manufacturing time, machine tool 1 can reduce the energy consumed when manufacturing irregularly shaped parts, enabling environmentally friendly part processing.

[0036] (Modification of machine tool according to embodiment) In machine tool 1, second spindle 12 is mounted so that it is perpendicular to first spindle 11 and the extension direction of second rotation axis A2 of second spindle 12 is shifted by 90 degrees from the extension direction of first rotation axis A1 of first spindle 11. However, in the machine tool according to the embodiment, second spindle 12 only needs to be rotatably mounted in a second rotation state in which the extension direction of second rotation axis A2 is not parallel to the extension direction of first rotation axis A1 and the first spindle 11 can turn in an extension direction different from the first rotation state when turning a workpiece.

[0037] FIG. 3 is a schematic diagram of a machine tool according to a first modified example.

[0038] The machine tool 2 differs from the machine tool 1 in the extension direction of the second rotation axis A2 of the second main spindle 12. The configurations and functions of the components of the machine tool 2 other than the extension direction of the second rotation axis A2 of the second main spindle 12 are the same as the configurations and functions of the components of the machine tool 1 that are assigned the same reference numerals, and therefore detailed description thereof will be omitted here.

[0039] In the machine tool 2, in the second rotation state, the second chuck 12a of the second spindle 12 grips a second gripping portion that is different from the first gripping portion that grips the workpiece by the first chuck 11a of the first spindle 11. In the machine tool 2, the second rotation axis A2 of the second spindle 12 extends from the second gripping portion in a direction shifted by 135 degrees from the extension direction of the first rotation axis A1 of the first spindle 11.

[0040] The second rotation axis A2 of the second spindle 12 extends in a direction shifted by 135 degrees from the extension direction of the first rotation axis A1, so that the machine tool 2 can turn the workpiece along two directions shifted by 45 degrees.

[0041] In the machine tool 2, the second rotation axis A2 extends from the second gripping part in a direction shifted by 135 degrees from the extension direction of the first rotation axis A1, but in the machine tool according to the embodiment, the second rotation axis A2 may extend in a direction different from the extension direction of the first rotation axis A1. In the machine tool according to the embodiment, the second main spindle 12 may be placed on a rotating table that supports the second main spindle 12 on the surface of the bed 10 so that the second main spindle 12 can rotate about the B axis, so that the angle between the first rotation axis A1 and the second rotation axis A2 can be changed.

[0042] Furthermore, machine tools 1 and 2 have a first spindle 11 and a second spindle 12, but the machine tool according to the embodiment may further have, in addition to the first spindle 11 and the second spindle 12, a third spindle placed opposite the first spindle 11.

[0043] FIG. 4 is a schematic diagram of a machine tool according to a second modified example.

[0044] Machine tool 3 differs from machine tool 1 in that it includes a third spindle 13 mounted opposite first spindle 11. The configurations and functions of the components of machine tool 3 other than third spindle 13 are identical to those of machine tool 1 with the same reference numerals, and therefore will not be described in detail here. Machine tool 3 machines a workpiece held by any of first spindle 11, second spindle 12, and third spindle 13, which are arranged in a T-shape, using first tool 21 to third tool 23 held by first tool rest 31 to third tool rest 33, respectively. When the workpiece is held by first spindle 11, machine tool 3 machines the workpiece using first tool 21, which is arranged so as to be able to turn the workpiece in a direction perpendicular to first rotation axis A1. When the workpiece is held by second spindle 12, machine tool 3 machines the workpiece using second tool 22, which is arranged so as to be able to turn the workpiece in a direction perpendicular to second rotation axis A2. When the workpiece is gripped by the third spindle 13, the machine tool 3 machines the workpiece with a third tool 23 that is arranged so as to be able to turn the workpiece in a direction perpendicular to the third rotation axis A3. The first rotation axis A1 of the first spindle 11, the second rotation axis A2 of the second spindle 12, and the third rotation axis A3 of the third spindle 13 are arranged on the same plane. Furthermore, the third rotation axis A3 is arranged in a straight line with the first rotation axis A1.

[0045] The third spindle 13, also referred to as the back spindle, has a third chuck 13a that grips a workpiece with a third gripping portion, which is the end opposite to the first gripping portion that grips the workpiece of the first chuck 11a. The third spindle 13 is placed on the bed 10 opposite the first spindle 11 and is movable along the Z direction. The third spindle 13 rotates around a third rotation axis A3 that extends in the Z direction parallel to the first rotation axis A1, thereby rotating the workpiece gripped by the third chuck 13a in a third rotation state around the third rotation axis A3. In the third rotation state, the third spindle 13 rotates so as to be able to turn the workpiece gripped by the third chuck 13a along the Z direction. The third chuck 13a is, for example, a two-jaw chuck controlled by compressed air, similar to the first chuck 11a and the second chuck 12a.

[0046] The machine tool 3 may perform a turning process using only one of the first to third spindles 11 to 13, or may perform a turning process using the first spindle 11 and the third spindle 13 or the second spindle 12, which are arranged opposite to each other. The machine tool 3 may also perform a further turning process using the first spindle 11 and the second spindle 12 in sequence. The machine tool 3 may also perform a further turning process using the first spindle 11, the second spindle 12, and the third spindle 13 in sequence. The machine tool 3 may also perform a turning process using the first spindle 11 and the second spindle 12, and then, after performing a turning process using the first spindle 11 and the second spindle 12, grip the workpiece held by the second chuck 12a of the second spindle 12 in the third chuck 13a of the third spindle 13, and perform a further turning process using the third spindle 13. When performing a turning process using the first spindle 11 and the third spindle 13, the workpiece may be transferred directly from the first chuck 11a to the third chuck 13a, or may be transferred from the first chuck 11a to the third chuck 13a via the second chuck 12a. When transferring the workpiece directly from the first chuck 11a to the third chuck 13a, the NC device 15 retracts the second spindle 12 to a region that does not interfere with the transfer of the workpiece.

[0047] Furthermore, the machine tool 3 has three spindles, the first spindle 11 to the third spindle 13, but the machine tool according to the embodiment may have, in addition to the first spindle 11 to the third spindle 13, a spindle that is placed opposite the second spindle 12.

[0048] FIG. 5 is a schematic diagram of a machine tool according to a third modified example.

[0049] Machine tool 4 differs from machine tool 3 in that it has a fourth spindle 14 placed opposite second spindle 12. The configurations and functions of the components of machine tool 4 other than fourth spindle 14 are identical to those of machine tool 3 with the same reference numerals, and therefore will not be described in detail here. Machine tool 4 machines a workpiece held by any of first spindle 11, second spindle 12, third spindle 13, and fourth spindle 14, which are arranged in a cross shape, using first tool 21 to fourth tool 24 held by first tool rest 31 to fourth tool rest 34. When the workpiece is held by first spindle 11, machine tool 4 machines the workpiece using first tool 21, which is arranged so as to be able to turn in a direction perpendicular to first rotation axis A1. When the workpiece is held by second spindle 12, machine tool 4 machines the workpiece using second tool 22, which is arranged so as to be able to turn in a direction perpendicular to second rotation axis A2. When the workpiece is gripped by the third spindle 13, the machine tool 4 machines the workpiece with a third tool 23 arranged to be able to turn the workpiece in a direction perpendicular to the third rotation axis A3. When the workpiece is gripped by the fourth spindle 14, the machine tool 4 machines the workpiece with a fourth tool 24 arranged to be able to turn the workpiece in a direction perpendicular to the fourth rotation axis A4. The first rotation axis A1 of the first spindle 11, the second rotation axis A2 of the second spindle 12, the third rotation axis A3 of the third spindle 13, and the fourth rotation axis A4 of the fourth spindle 14 are arranged on the same plane. Furthermore, the third rotation axis A3 is arranged in a straight line with the first rotation axis A1, and the fourth rotation axis A4 is arranged in a straight line with the second rotation axis A2.

[0050] The fourth spindle 14 has a fourth chuck 14a that grips a workpiece with a fourth gripping portion, which is the end opposite to the second gripping portion that grips the workpiece of the second chuck 12a. The fourth spindle 14 is placed on the bed 10 opposite to the second spindle 12 and is movable along the X direction. The fourth spindle 14 rotates about a fourth rotation axis A4 that extends in the X direction parallel to the second rotation axis A2, thereby rotating the workpiece gripped by the fourth chuck 14a in a fourth rotation state in which the workpiece rotates about the fourth rotation axis A4. In the fourth rotation state, the fourth spindle 14 rotates so as to be able to turn the workpiece gripped by the fourth chuck 14a along the Z direction. The fourth chuck 14a is, for example, a two-jaw chuck controlled by compressed air, similar to the first chucks 11a to 13a.

[0051] The machine tool 4 may perform a turning process using only one of the first to fourth spindles 11 to 14, or may perform a turning process using the first and third spindles 11 and 13 or the second and fourth spindles 12 and 14, which are arranged opposite to each other. The machine tool 4 may also perform a further turning process using the first and second spindles 11 and 12 in sequence, or may perform a further turning process using the first and fourth spindles 11 and 14 in sequence. The machine tool 4 may also perform a further turning process using the first, second and third spindles 11 and 13 in sequence, or may perform a further turning process using the first, fourth and third spindles 14 in sequence. Furthermore, the machine tool 4 may further perform a turning process by sequentially using the first spindle 11, the second spindle 12, the third spindle 13, and the fourth spindle 14, or may further perform a turning process by sequentially using the first spindle 11, the fourth spindle 14, the third spindle 13, and the second spindle 12. When performing a turning process by using the first spindle 11 and the third spindle 13, the workpiece may be transferred directly from the first chuck 11a to the third chuck 13a, or may be transferred from the first chuck 11a to the third chuck 13a via the second chuck 12a. When directly transferring the workpiece from the first chuck 11a to the third chuck 13a, the NC device 15 retracts the second spindle 12 and the fourth spindle 14 to an area where they do not interfere with the transfer of the workpiece. Furthermore, when performing a turning process using the second spindle 12 and the fourth spindle 14, the workpiece may be transferred directly from the second chuck 12a to the fourth chuck 14a. Alternatively, the workpiece may be transferred from the second chuck 12a to the fourth chuck 14a via the first chuck 11a or the third chuck 13a. Furthermore, when transferring the workpiece directly from the second chuck 12a to the fourth chuck 14a, the NC device 15 retracts the first spindle 11 and the third spindle 13 to an area where they do not interfere with the transfer of the workpiece.

[0052] Furthermore, machine tools 1 to 4 turn workpieces having a square timber shape, but the machine tools according to the embodiment may also turn workpieces that have been formed by cutting off a rod-shaped workpiece supplied from a work supply device.

[0053] Furthermore, in machine tools 1 to 4, the first spindle 11 to fourth spindle 14 have first chuck 11a to fourth chuck 14a, which are two-jaw chucks controlled by compressed air. However, in the machine tool according to the embodiment, each of the first chuck 11a to fourth chuck 14a may be controlled hydraulically. Furthermore, in the machine tool according to the embodiment, each of the first chuck 11a to fourth chuck 14a may be a chuck other than a two-jaw chuck, such as a three-jaw chuck or a four-jaw chuck. Note that each of the first chuck 11a to fourth chuck 14a is preferably a two-jaw chuck when gripping a part made of irregularly shaped material. Furthermore, in the machine tool according to the embodiment, each of the first chuck 11a to fourth chuck 14a may be a long-stroke chuck.

[0054] Furthermore, in the machine tools 1 to 4, the first rotation axis A1, the second rotation axis A2, the third rotation axis A3, and the fourth rotation axis A4 are arranged on the same plane, but in the machine tool according to the embodiment, the first rotation axis A1 to the fourth rotation axis A4 do not have to be arranged on the same plane. Also, in the machine tool according to the embodiment, the first rotation axis A1 to the fourth rotation axis A4 may be arranged in a twisted position. Also, in the machine tool according to the embodiment, the first rotation axis A1 to the fourth rotation axis A4 may each be movable in the Y direction.

[0055] Furthermore, in machine tools 1 to 4, first spindle 11, second spindle 12, third spindle 13, and fourth spindle 14 are arranged on bed 10, but in the machine tool according to the embodiment, at least one of first spindle 11, second spindle 12, third spindle 13, and fourth spindle 14 does not have to be arranged on bed 10. For example, first spindle 11 may be arranged on bed 10, and second spindle 12 may not be arranged on bed 10, but may be arranged such that second rotation axis A2 extends in the normal direction of bed 10. When first spindle 11 and second spindle 12 are arranged in the same plane, and second spindle 12 is arranged such that second rotation axis A2 extends in the normal direction of bed 10, the plane on which first spindle 11 and second spindle 12 are arranged is perpendicular to a plane parallel to bed 10.

[0056] Furthermore, the second main shaft 12 may be arranged so that the second rotation axis A2 extends in a direction different from the normal direction of the bed 10. When the first main shaft 11 and the second main shaft 12 are arranged on the same plane and the second main shaft 12 is arranged so that the second rotation axis A2 extends in a direction different from the normal direction of the bed 10, the plane on which the first main shaft 11 and the second main shaft 12 are arranged intersects with the bed 10, i.e., with a plane parallel to the guide surface of the bed 10.

[0057] Furthermore, the first main spindle 11 and the third main spindle 13 may be disposed on the bed 10, and the second main spindle 12 may not be disposed on the bed 10, or the first main spindle 11 and the second main spindle 12 may be disposed on the bed 10, and the third main spindle 13 may not be disposed on the bed 10. The first main spindle 11, the second main spindle 12, and the third main spindle 13 may be disposed on the same plane, or may be disposed on a different plane from the first main spindle 11, the second main spindle 12, and the third main spindle 13.

[0058] Furthermore, the first main spindle 11, the third main spindle 13, and the fourth main spindle 14 may be disposed on the bed 10, and the second main spindle 12 may not be disposed on the bed 10, or the first main spindle 11, the second main spindle 12, and the fourth main spindle 14 may be disposed on the bed 10, and the third main spindle 13 may not be disposed on the bed 10. The first main spindle 11, the second main spindle 12, the third main spindle 13, and the fourth main spindle 14 may be disposed on the same plane, or may be disposed on a different plane from the first main spindle 11, the second main spindle 12, the third main spindle 13, and the fourth main spindle 14.

[0059] In addition, in machine tools 3 and 4, the third rotation axis A3 is arranged in a straight line with the first rotation axis A1, but in the machine tool according to the embodiment, the third rotation axis A3 may not be arranged in a straight line with the first rotation axis A1, may not be arranged in the same plane as the first rotation axis A1, and may be arranged in a different plane. Furthermore, in machine tool 4, the fourth rotation axis A4 is arranged in a straight line with the second rotation axis A2, but in the machine tool according to the embodiment, the fourth rotation axis A4 does not have to be arranged in a straight line with the second rotation axis A2.

[0060] Furthermore, in machine tools 1 to 4, the first tool 21 to the fourth tool 24 are held on separate first tool rests 31 to 34, respectively, but in the machine tool according to the embodiment, the first tool 21 to the fourth tool 24 may be held on a single tool rest.

[0061] 2, the first protrusion W1 and the second protrusion W2, which are cylindrical protrusions, are formed on the workpiece, but in the turning process using the machine tool according to the embodiment, the formed protrusions may be prismatic or frustum-shaped. In addition, in the turning process using the machine tool according to the embodiment, recesses or holes may be formed in the workpiece by drilling.

Claims

1. A machine tool comprising: a tool holding unit that holds a tool; a first spindle that grips a workpiece and is rotatable in a first rotational state so as to be able to turn the gripped workpiece along a first direction of the workpiece; a second spindle that grips a workpiece and is rotatable in a second rotational state so as to be able to turn the gripped workpiece along a second direction of the workpiece that is different from the first direction; and a control unit that controls the first spindle, the second spindle, and the tool holding unit so as to turn the workpiece using the tool held by the tool holding unit.

2. A machine tool as described in claim 1, wherein in the first rotation state, the workpiece gripped by the first spindle rotates around a first rotation axis, and in the second rotation state, the workpiece gripped by the second spindle rotates around a second rotation axis that extends in a different direction from the first rotation axis.

3. A machine tool as described in claim 2, wherein the first spindle grips a first gripping portion which is one end of the workpiece, the second spindle grips a second gripping portion different from the first gripping portion, the first rotating shaft extends from the first gripping portion toward the other end of the workpiece, and the second rotating shaft extends from the second gripping portion in a direction different from the extension direction of the first rotating shaft.

4. The machine tool according to claim 3, wherein the control unit causes the first spindle to grip a workpiece; in the first rotation state, turns the workpiece gripped by the first spindle using a tool held by the tool holding unit; causes the second spindle to grip the workpiece turned in the first rotation state; and in the second rotation state, turns the workpiece gripped by the second spindle using a tool held by the tool holding unit.

5. A machine tool as set forth in claim 2, further comprising a third spindle arranged opposite said first spindle, for gripping a workpiece, and for rotating the gripped workpiece about a third rotation axis extending parallel to said first rotation axis.

6. A machine tool according to claim 5, further comprising a fourth spindle arranged opposite said second spindle, for gripping a workpiece and for rotating the gripped workpiece about a fourth rotation axis extending parallel to said second rotation axis.

7. A machine tool according to any one of claims 2 to 6, wherein the first rotation axis extends in a direction perpendicular to the extension direction of the second rotation axis.

8. A machine tool according to any one of claims 2 to 6, wherein the first spindle is arranged in a different plane from the second spindle.

9. [Amendment under Rule 91 01.09.2025] A machine tool according to any one of claims 2 to 6, wherein the first spindle and the second spindle are arranged in the same plane.

10. The machine tool according to claim 9, wherein the same plane intersects with a plane parallel to the bed.

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