machine tool

Abstract

Machine tool (10) for machining a workpiece by means of a cutting tool (32a), the machine tool (10) comprising: a first holding device for holding a tool (32, 32a, 32b, 32c); a second holding device for holding the tool (32, 32a, 32b, 32c); a storage unit (26) for storing one or more tools (32, 32a, 32b, 32c); an exchange mechanism (28) for exchanging the tools (32, 32a, 32b, 32c) between the second holding device and the storage unit (26), wherein the exchange mechanism (28) cannot directly access the first holding device; a robot (24) for exchanging the tools (32, 32a, 32b, 32c) between the first holding device and the second holding device; and a control device (39) for controlling the driving of the first holding device, the second holding device, the exchange mechanism (28) and the robot (24), wherein the control device (39) carries out the control such that the tools (32, 32a, 32b, 32c) are exchanged between the first holding device and the storage unit (26) via the robot (24), the second holding device and the exchange mechanism (28), characterized in that the first holding device and the second holding device are installed in a processing chamber (12), wherein the second holding device is a tool main spindle (18) or a tool stand (20) which holds a cutting tool (32a) as the tool (32, 32a, 32b, 32c), and the exchange mechanism (28) is an automatic tool changing device which includes an exchange arm (50) and / or a robot arm.

Description

Technical area

[0001] This patent application relates to a machine tool for machining a workpiece using a cutting tool. background

[0002] A machine tool for machining a workpiece by means of a cutting tool is equipped with a holding device for holding various tools (a cutting tool or a tailstock tool) such as a tool post or a tool main spindle holding a cutting tool or a tailstock holding a tailstock tool.

[0003] In such a holding device, the tool to be held is changed depending, for example, on the type of machining to be performed or the type of workpiece to be machined. In the above example, tool change is proposed by a robot instead of an operator.

[0004] For example, document JP 2016-55370 A discloses an automatic tool exchange device equipped with a robot arm and a movement mechanism for moving the robot arm for automatically exchanging tools to be mounted on the lower tool post of a machine tool. According to this document, the movement mechanism includes, for example, a linear guide and a servo motor for moving the robot arm between a tool storage device and a main spindle. The robot arm has a gripper for removably gripping a tool.

[0005] JP H 05-285766 A discloses a tool carrier device equipped with a six-axis articulated robot and a tool exchange gripper attached to the wrist of the robot. The robot moves the tool exchange gripper between a tool rack and a tool storage unit and automatically exchanges the tools to be mounted on the tool rack. Furthermore, this document discloses the exchange of chucks using the tool carrier device in addition to tools.

[0006] Such a technique for exchanging tools using a robot significantly reduces a load imposed on an operator.

[0007] JP S58-223543 A discloses an automatic tool changing device in which a tool is conveyed and exchanged between a spindle head and a tool magazine by means of a tool carrier by a drive means, the drive means being driven by a control device. DE 10 2018 208 466 A1 discloses a machine tool with an automatic tool changer that automatically changes a tool to be mounted on the main spindle by moving an arm in a plane perpendicular to the main spindle. JP 6321309 B1 discloses a machine tool with a tool storage device. EP 2 992 995 B1 discloses a machine tool with an automatic tool changer for automatically changing a tool attached to a tool suspension of a machine tool, comprising, inter alia, a robot arm. DE 10 2016 109 011 A1 discloses a machine tool with a cooling fluid supply part which is designed to supply a cooling fluid. DE 10 2016 121 599 A1 discloses a machine tool with a changing device and a communication device. DE 38 17 161 A1 discloses a cylindrical grinding machine with a numerical control for grinding chuck and center workpieces.

[0008] A disadvantage of conventional tool exchange using a robot is that it requires the installation of a tool holding device (e.g., a tool post or tailstock) and a tool storage device within the range in which the robot can move. This requirement can impose a constraint on the design of these devices. While setting a larger robot movement range can obviously increase the degree of freedom in designing the tool holding device and storage device, such an increased robot movement range increases the number of issues that require consideration, such as how to avoid interference between a robot and other elements.

[0009] In view of the above, this patent application discloses a machine tool suitable for automatic tool exchange for a variety of tool holding devices while avoiding excessive enlargement of the range in which a robot can move. Summary

[0010] A machine tool disclosed in this patent application is a machine tool for machining a workpiece by means of a cutting tool having the features of claim 1, the machine tool comprising: a first holding device installed in a machining chamber, the first holding device serving to hold a tool; a second holding device installed in the machining chamber, the second holding device serving to hold the tool; a storage unit for storing one or more tools; an exchange mechanism for exchanging the tools between the second holding device and the storage unit, the exchange mechanism not having direct access to the first holding device; a robot for exchanging the tools between the first holding device and the second holding device.and a control device for controlling the driving of the first holding device, the second holding device, the exchange mechanism, and the robot, wherein the control device performs the control such that the tools are exchanged between the first holding device and the storage unit via the robot, the second holding device, and the exchange mechanism;

[0011] According to the invention, the second holding device is a tool main spindle or a tool post that holds a cutting tool as the tool, and the exchange mechanism is an automatic tool changing device that includes an exchange arm and / or a robot arm.

[0012] The first holding device may be a tool post that holds a cutting tool as the tool. The first holding device may be a workpiece main spindle that holds a chuck jaw as the tool. The first holding device may be a tailstock that holds a tailstock tool as the tool.

[0013] The second holding device can hold a tool that is specifically provided for the first holding device via a tool connector that has the same shape as the tool holder of the first holding device and a machine connector that is designed to be mounted on the tool holder of the second holding device.

[0014] The machine tool may further include a cleaning mechanism for cleaning around the tool held on the first holding device, and the control device may cause the cleaning mechanism to clean around the tool before the tool exchange between the first holding device and the storage unit.

[0015] The robot may include a main body and one or more end effectors interchangeably mounted on the main body. The end effector to be mounted on the robot may be selected from a group including an end effector for gripping an object and an end effector for cleaning around the tool held on the first holding device.

[0016] According to the machine tool disclosed in this patent application, automatic tool exchange is also achieved with respect to the first holding device without excessively increasing the range of motion of the robot. Brief description of the drawings

[0017] An embodiment or embodiments of the present disclosure will be described based on the following figures, in which: Fig. 1 a perspective view of a machine tool; Fig. 2 a perspective view of a machine tool; Fig. 3 a perspective view of a machine tool; Fig. 4 an example of a tool holder; Fig. 5 an example of an exchange mechanism; Fig. 6 another example of a tool holder; Fig. 7 a perspective view of a machine tool; Fig. 8 a perspective view of a machine tool; Fig. 9 a perspective view of a machine tool; Fig. 10 is a perspective view of the vicinity of a main spindle end portion; Fig. 11 another example of a tool holder; Fig. 12 a perspective view of another machine tool; Fig. 13 a perspective view of another machine tool; Fig. 14 a perspective view of another machine tool; and Fig. 15 a schematic plan view of another machine tool. Description of the embodiments

[0018] The structure of a machine tool 10 will now be described with reference to the drawings. Fig. 1 to Fig. 3 are perspective views of the machine tool 10 illustrating the replacement of a cutting tool 32a or a type of tool 32. Fig. 4 and Fig. 6 illustrate examples of a tool holder 42. Fig. Figure 5 illustrates an example of an exchange mechanism 28.

[0019] The machine tool 10 is a cutting machine for cutting a workpiece (not illustrated) with the cutting tool 32a. Specifically, the machine tool 10 in this embodiment is a multi-purpose machine equipped with a tool main spindle 18 used primarily for rotation and a lower tool post 20 used primarily for turning. It should be noted that the machine tool 10 disclosed herein is merely an example, and the technique disclosed in this patent application is applicable to any other types of machine tools 10.

[0020] A processing chamber 12 of the machine tool 10 is covered. The processing chamber 12 has a large opening on its front surface. The opening is opened and closed by a front door 14. An operator accesses the respective units in the processing chamber 12 through the opening. During processing, the front door 14 provided at the opening is kept closed to ensure safety and a suitable environment.

[0021] The machine tool 10 includes a workpiece main spindle 16 that rotatably holds an end portion of a workpiece. The workpiece main spindle 16 can rotate by means of a motor (not shown). On one end surface of the workpiece main spindle 16, i.e., a main spindle end 34, a plurality of clamping head claws 32b for detachably holding a workpiece are mounted. Specifically, the plurality of clamping head claws 32b are arranged equidistantly in the circumferential direction and can move in the radial direction.

[0022] As described above, the machine tool 10 includes the lower tool post 20 and also the tool main spindle 18. The lower tool post 20 holds a cutting tool 32a or a kind of tool 32 and functions as a first holding device accessed by the exchange mechanism 28, which will be described later (in Fig. 1 to Fig. 3), cannot be directly accessed. This tool post is movable in the Z-axis direction or a direction parallel to the axis of a workpiece. The tool post is also movable in a direction parallel to the X-axis or the radial direction of a workpiece. In this embodiment, the X-axis is inclined upward with respect to the horizontal direction, while being farther away from the opening of the processing chamber 12 in the direction opposite to the opening.

[0023] Mounted on the end surface of the lower tool post 20 in the Z direction is a turret 22 capable of holding a plurality of cutting tools 32a. The turret 22 is polygonal in the Z-axis direction and can rotate around an axis parallel to the Z-axis as a center. Mounted on the peripheral surface of the turret 22 are a plurality of tool holders to which cutting tools 32a are to be mounted. Rotating the turret 22 enables the exchange of the cutting tools 32a to be used during machining.

[0024] It should be noted that the cutting tool 32a to be held on the lower tool post 20 (which contains the turret 22) may be a turning tool for use in turning or a rotary tool for use in rotation. In either case, the cutting tool 32a to be held on the lower tool post 20 is exchanged via an internal robot 24, the main tool spindle 18, and the exchange mechanism 28.

[0025] The main tool spindle 18 rotatably holds the cutting tool 32a or a type of tool and functions as a second holding device that can be directly accessed by the exchange mechanism 28. The main tool spindle 18 is movable in three axes and has a range of motion that allows the main tool spindle 18 to access a workpiece held by at least the internal robot 24 described later, the exchange mechanism 28, and the workpiece main spindle 16. Furthermore, a tool holder to which the cutting tool 32a is to be attached is mounted on one end surface of the main tool spindle.

[0026] The cutting tool 32a to be held on the main tool spindle 18 may also be a turning tool for use in turning or a rotary tool for use in rotation. In either case, the cutting tool 32a to be held on the main tool spindle 18 is exchanged by the exchange mechanism 28 without the intervention of the internal robot 24.

[0027] Both the lower tool post 20 and the main tool spindle 18 can hold the cutting tool 32a either directly or via the tool holder 42. In the following, for the sake of simplicity of description, it is assumed that the tool holder of the lower tool post 20 has the same shape as the main tool spindle 18 and that both the lower tool post 20 and the main tool spindle 18 hold the cutting tool 32a via the tool holder 42, which in Fig. 4 is illustrated.

[0028] This tool holder 42 includes a machine connector 42m to be connected to a machine, that is, either the lower tool post 20 or the main tool spindle 18, a tool connector 42t to be connected to the cutting tool 32a (the tool 32), and an engagement unit 42e to be engaged with an exchange arm 50 of the exchange mechanism 28, which will be described later. The machine connector 42m has a shape in accordance with the tool holders of the main tool spindle 18 and the lower tool post 20. Specifically, the machine connector 42m may have a shape in accordance with a general standard, such as a chamfered shank shape. The tool connector 42t is a member to be connected to the cutting tool 32a and can be appropriately changed depending on the shape of the cutting tool 32a that is desired to be used.The engagement unit 42e may have any shape without limitation, provided that the shape enables engagement with the exchange arm 50. For example, the engagement unit 42e may be a circumferentially extending groove, as shown in FIG. Fig. 4. The engagement unit 42e may include, for example, a hole, a projection, or a notch in addition to or instead of the groove.

[0029] The machine tool 10 further includes the internal robot 24, a storage unit 26 and the exchange mechanism 28 (see Fig. 5). The internal robot 24 is a robot installed in the processing chamber 12. In this embodiment, the internal robot 24 is a serial multi-joint robot including a plurality of robot arms 38 connected in series via joints. The main body of the internal robot 24, which includes a plurality of robot arms 38, has an end effector 40 replaceably attached thereto. The end effector 40 has a specific function and is to be attached to a robot. Examples of such an end effector 40 include a gripping element for gripping the tool 32 (e.g., a gripper or a gripping hand mechanism), a sensor for detecting physical quantities such as temperature or vibration, a roller for supporting a workpiece being processed, and a cleaning mechanism for cleaning an object.Examples of the cleaning mechanism include a fluid discharge nozzle for discharging a fluid such as cutting oil or air, a brush or scraper for removing foreign materials, and a suction nozzle for sucking foreign materials. The end effector 40 to be mounted on the internal robot 24 is appropriately selected from a group including a gripper and a cleaning mechanism depending on the progress of various types of processing by the machine tool 10.

[0030] The internal robot 24 is movable in the Z-axis direction, and the angles of the respective robot arms 38 can be freely changed. By moving the internal robot 24 in the Z-axis direction or changing the angles of the robot arms 38, the position of the end effector 40 is thereby changed. In this embodiment, the internal robot 24 has a movement range that allows its end effector 40 to access the main tool spindle 18 (the second holding device) and the lower tool post 20 (the first holding device). Note that the movement range may not allow the end effector 40 to access the exchange mechanism 28.

[0031] The storage unit 26 is an element in which various types of tools 32 are stored. In this embodiment, the storage unit 26 is provided inside the machine tool 10. More specifically, the storage unit 26, as shown in Fig. 1 to Fig. 3, is provided inside relative to a wall surface from which the workpiece main spindle 16 protrudes. The storage unit 26 is closed with a flap when the tool 32 is not interacting with the outside.

[0032] The exchange mechanism 28 is installed near the storage unit 26. The exchange mechanism 28 exchanges the tools 32 between the storage unit 26 and the main tool spindle 18 (the second holding device). An automatic tool changer (hereinafter abbreviated as "ATC") conventionally provided on the machine tool 10 can be used as the exchange mechanism 28.

[0033] The ATC is a device for automatically exchanging a cutting tool, which is held, for example, on the tool main spindle in the machine tool 10. The structure of the ATC can be used as the exchange mechanism 28 in this embodiment. For example, the exchange mechanism 28 as shown in Fig. 5, have the exchange arm 50 which is intended to engage with the engagement unit 42e of the tool holder 42 in order to hook it.

[0034] Steps for exchanging the cutting tools 32a to be held on the tool main spindle 18 by means of the exchange arm 50 which is in Fig. 5 will be briefly described. In this case, the exchange arm 50 has the engagement hooks 52 for engaging with the engagement unit 42e of the tool holder 42m, each of which is located on one of its two end portions. The exchange arm 50 is rotatable about a vertical axis and can be lifted in the vertical direction. In this case, the storage unit 26 has a tool magazine 48 for holding a plurality of cutting tools 32a via the respective tool holders 42. The tool magazine 48 can rotate about a vertical axis.

[0035] When exchanging the cutting tools 32a, both the tool holder 42 (containing the cutting tool 32a) mounted on the main tool spindle 18 and a tool holder 42 (containing the cutting tool 32a) that is desired to be newly mounted on the main tool spindle 18 are arranged on the rotation track of the engagement hook 52. Then, the exchange arm 50 is rotated in a direction such that the exchange arm 50 is engaged with the respective engagement units 42a of the tool holders 42. Once the exchange arm 50 is engaged with the two tool holders 42, the exchange arm 50 descends, thereby pulling the two tool holders 42 out of the tool magazine 48 and the main tool spindle 18, respectively. The exchange arm 50 is then rotated again by 180° in one direction to exchange the positions of the two tool holders 42.The exchange arm 50 then rises to insert the two tool holders 42 into the tool magazine 48 and the main tool spindle 18, respectively. This completes the exchange of the cutting tools 32a. It should be noted that the structure of the exchange mechanism 28 described above is merely an example, and other mechanisms may be used instead.

[0036] A controller 39 controls the driving of the aforementioned workpiece main spindle 16, the lower tool post 20, the main tool spindle 18, the internal robot 24, and the exchange mechanism 28, and includes, for example, a processor for executing various operations and a data memory for storing various programs and data. The controller 39 may include, for example, a numerical control device. The controller 39 controls the driving of the workpiece main spindle 16, the lower tool post 20, and the main tool spindle 18 based on a machining program (an NC program) input by an operator to machine a workpiece. Furthermore, the controller 39 performs control such that the cutting tools 32a are exchanged between the lower tool post 20 and the storage unit 26 via the internal robot 24, the main tool spindle 18, and the exchange mechanism 28.This is described in detail below.

[0037] As described above, the machine tool 10 in this embodiment includes the exchange mechanism 28 for exchanging the cutting tools 32a to be mounted on the main tool spindle 18. The provision of the exchange mechanism 28 enables automatic exchange of the cutting tool 32a to be mounted on the main tool spindle 18. In contrast, the cutting tool 32a to be mounted on the lower tool post 20 cannot be directly exchanged by the exchange mechanism 28 because the lower tool post 20 is located away from the exchange mechanism 28.

[0038] To address this problem, one possibility is to install an additional exchange mechanism 28 and an additional storage unit 26 near the lower tool post 20. However, in this case, an increase in cost and an increase in the size of the machine tool 10 will result. Although another possibility is to increase the range in which the internal robot 24 can move so that the internal robot 24 can carry the cutting tool 32a from the storage unit 26 to the lower tool post 20 or from the lower tool post 20 to the storage unit 26, in this case, with an increased range of movement of the internal robot 24, the problem of increased cost is also unavoidable. In addition, an increase in the range of movement due to an increase in the size of the internal robot 24 may make it impossible to increase the range of movement due to interference in the machining chamber.

[0039] In view of the above, in this embodiment, the exchange of the cutting tools 32a between the lower tool post 20 (the first holding device) and the storage unit 26 is achieved with the operation of the internal robot 24, the tool main spindle 18 (the second holding device), and the exchange mechanism 28. A process for storing the cutting tool 32a mounted on the lower tool post 20 for exchange in the storage unit 26 will be specifically described below.

[0040] Initially, the controller 39 drives the internal robot 24 to clean the cutting tool 32a on the lower tool post 20, and the cutting tool 32a is to be replaced. In the above, a cleaning mechanism (e.g., a fluid ejection nozzle or a brush) is mounted on the internal robot 24 as the end effector 40. Subsequently, the controller 39 drives the internal robot 24 to remove the cutting tool 32a together with the tool holder 42 from the lower tool post 20. In the above, a gripping mechanism is mounted on the internal robot 24 as the end effector 40.

[0041] Further, the controller 39 drives the internal robot 24 to mount the cutting tool 32a, which has been removed from the lower tool post 20, onto the main tool spindle 18. In the above, the controller 39 moves the main tool spindle 18 into the movement range of the internal robot 24, if necessary. Subsequently, the controller 39 moves the main tool spindle 18 to a predetermined main-spindle-side replacement position. Then, the controller 39 opens the door 27 of the storage unit 26 and places the cutting tool 32a on the main tool spindle 18 (that is, the cutting tool 32a that has been removed from the lower tool post 20) into the storage unit 26 using the replacement arm 50 of the replacement mechanism 28.At the same time, the cutting tool 32a to be newly mounted on the lower tool stand 20 is mounted on the tool main spindle 18 by means of the exchange arm 50.

[0042] Once the cutting tool 32a is newly mounted on the main tool spindle 18, the controller 39 moves the main tool spindle 18 into the movement range of the internal robot 24 and then drives the internal robot 24 to mount the cutting tool 32a on the main tool spindle 18 on the lower tool post 20. This completes the exchange of the cutting tools 32a between the lower tool post 20 and the storage unit 26.

[0043] As apparent from the above description, in this embodiment, the main tool spindle 18 is engaged for exchanging the cutting tools 32a between the storage unit 26 and the lower tool post 20, which are arranged remotely from each other. Since the machine tool 10 includes the exchange mechanism 28 for exchanging the cutting tools 32a to be mounted on the main tool spindle 18, engagement of the main tool spindle 18 enables tool exchange between the lower tool post 20 and the storage unit 26 without providing an additional exchange mechanism 28. Consequently, automatic tool exchange can also be achieved with respect to the first holding device (the lower tool post 20) arranged remotely from the storage unit 26, while preventing an increase in cost and an increase in size.

[0044] In the above description, the tool holder of the main tool spindle 18 has the same shape as that of the lower tool post 20. Alternatively, the tool holder of the main tool spindle 18 may have a different shape from that of the lower tool post 20. In this case, the main tool spindle 18 uses the tool holder 42, which in Fig. 6, in holding the cutting tool 32a to be mounted on the lower tool post 20. Specifically, the tool connector 42t of the tool holder 42 has the same shape as the lower tool post 20 (the first holding device), and the machine connector 42m of the tool holder 42 has a shape that allows the machine connector 42m to be mounted on the main tool spindle 18 (the second holding device). Therefore, the inclusion of the tool holder 42 makes it possible to compensate for the difference in the shape of the tool holder of the main tool spindle 18 and that of the lower tool post 20, so that it is possible to mount the cutting tool 32a, which is specifically designed for the lower tool post 20, on the main tool spindle 18.

[0045] Other embodiments will now be described with reference to Fig. 7 to Fig. 11 described. Fig. 7 to Fig. 9 are perspective views of the machine tool 10 illustrating the replacement of the clamping head jaws 32b or a type of tool 32. Fig. 10 is a schematic perspective view of the main spindle end 34. Fig. 11 is a perspective view of the tool holder 42 for use in replacing the clamping head jaws 32b.

[0046] As described earlier, the machine tool 10 includes the workpiece main spindle 16, and a plurality of (three in the illustrated example) chuck jaws 32b are mounted on one end portion of the workpiece main spindle 16, that is, the main spindle end 34. The chuck jaw 32b needs to be replaced in accordance with the shape of a workpiece to be machined. In this embodiment, the chuck jaw 32b is replaced via the interfacing of the replacement arm 50, the tool main spindle 18, and the internal robot 24. That is, in this case, the chuck jaw 32b functions as the tool 32, while the workpiece main spindle 16 functions as the first holding device that holds the tool 32 and is not accessed by the replacement mechanism 28.

[0047] As in Fig. As illustrated in Fig. 10, the main spindle end 34 has a notch 34a extending in the radial direction. The chuck claw 32b will slide into the notch 34a. The notch 34a serves as a tool holder defined on the workpiece main spindle 16 (the first holding device) into which the chuck claw 32b (a tool) is to be inserted. The chuck claw 32b, which is inserted into the notch 34a (a tool holder), is locked with a locking mechanism (not illustrated) using a spring or an electromagnetic cylinder, thereby preventing separation from the main spindle end 34. A locking hole 56 for releasing the locking mechanism is formed on the peripheral surface of the main spindle end 34.With a release pin (not illustrated) inserted into the locking hole 56, the locking mechanism is released so that the chuck jaw 32b can be removed from the main spindle end 34.

[0048] It should be noted here that the tool holder (the notch 34a) formed on the main spindle end 34 naturally has a different shape from that of the tool holder of the main tool spindle 18. To compensate for the difference in shape, the main tool spindle 18 holds the clamping head claw 32b over the tool holder 42, which is in Fig. 11. Specifically, the chuck claw 32b includes the number of tool connectors 42t, which are notches each having the same shape as that of the tool holder (the notch 34a) of the workpiece main spindle 16, the number being the same as the number of chuck claws 32b (three in this embodiment), in addition to the machine connector 42m configured to be mounted on the tool holder of the tool main spindle 18 and the engagement unit 42e configured to engage with the exchange arm 50.

[0049] Steps for replacing the clamping jaws 32b between the workpiece main spindle 16 (the first holding device) and the storage unit 26 in this machine tool 10 will be described. In this case, the controller 39 initially drives the internal robot 24 to clean the area around the clamping jaw 32b on the workpiece main spindle 16.

[0050] Subsequently, the control device 39 drives the internal robot 24 such that the clamping head claw 32b is removed from the workpiece main spindle 16 to mount the clamping head claw 32b on the tool holder 42 held on the tool main spindle 18. Specifically, a gripping mechanism (e.g., a gripper or a gripping hand mechanism) is initially mounted as an end effector 40 on the internal robot 24 to grip the release pin with the gripping mechanism (the end effector 40) and then insert the release pin into the locking hole 56 to thereby release the locking mechanism (see Fig. 8). Once the locking mechanism is released, the internal robot 24 is driven such that the clamping head claw 32b is held with the gripping mechanism, then the clamping head claw 32b is removed from the workpiece main spindle 16 and the clamping head claw 32b is mounted on the tool holder 42 (see Fig. 9). In the above, the main tool spindle 18 changes its position and posture for holding the tool holder 42 as necessary. This procedure is repeatedly performed with the same number of repetitions as the number of clamping head jaws 32b, specifically three in the illustrated example.

[0051] Once all the clamping head claws 32b are mounted on the tool holder 42, the control device 39 moves the main tool spindle 18, along with the respective tool holders 42, to a predetermined replacement position on the main spindle side. The control device 39 then opens the door 27 of the storage unit 26 and places the clamping head claws 32b on the main tool spindle 18, along with the tool holders 42, in the storage unit 26 using the replacement arm 50 of the replacement mechanism 28. At the same time, a clamping head claw 32b to be newly mounted on the workpiece main spindle 16 is mounted on the main tool spindle 18 using the replacement arm 50.

[0052] Once the clamping head claw 32b is newly mounted on the tool main spindle 18, the controller 39 moves the tool main spindle 18 into the movement range of the internal robot 24 and then drives the internal robot 24 to mount the clamping head claw 32b on the tool main spindle 18 on the workpiece main spindle 16. This completes the exchange of the clamping head claws 32b between the workpiece main spindle 16 and the storage unit 26.

[0053] As can be seen from the above description, in this embodiment, tools (the chuck jaws 32b) are also exchanged via the tool main spindle 18. This structure enables automatic tool exchange also with respect to the workpiece main spindle 16 (the first holding device), which cannot move with respect to the storage unit 26, while preventing an increase in cost and an increase in size.

[0054] Other embodiments will now be described with reference to Fig. 12 to Fig. 14 described. Fig. 12 to Fig. 14 are perspective views of another machine tool 10 illustrating the replacement of a tailstock tool 32c or a type of tool 32. The machine tool 10 in this embodiment has a tailstock 30 instead of the lower tool post 20, as shown in Fig. 12 to Fig. 14. The tailstock 30 is arranged opposite the workpiece main spindle 16 in the Z-axis direction and is movable in the Z-axis direction. The tailstock tool 32c is detachably mounted on one end of the tailstock 30. The tailstock tool 32c abuts against the tip end of a workpiece held on the workpiece main spindle 16, thereby supporting the workpiece. In this embodiment, the tailstock 30 functions as a first holding device that holds the tool 32 (the tailstock tool 32c).

[0055] In this embodiment, the main tool spindle 18 functions as the second holding device that forwards tool exchange (of the tailstock tool 32c). The tool holder 42, which detachably holds the tailstock tool 32c, is mounted on the main tool spindle 18.

[0056] Steps for exchanging the tailstock tools 32c between the tailstock 30 (the first holding device) and the storage unit 26 in the machine tool 10 will be described. In this case, the controller 39 initially drives the internal robot 24 to clean around the tailstock tool 32c mounted on the tailstock 30.

[0057] Subsequently, the control device 39 drives the internal robot 24 in such a way that the tailstock tool 32c is removed from the tailstock 30 and then the tailstock tool 32c is mounted on the tool holder 42 held on the main tool spindle 18 (see Fig. 13 and Fig. 14). As soon as the tailstock tool 32c is mounted on the main tool spindle 18, the control device 39 moves the main tool spindle 18 together with the tool holder 42 to a predetermined replacement position on the main spindle side. Subsequently, the control device 39 opens the flap 27 of the storage unit 26 (in Fig. 12 to Fig. 14 not illustrated) and places the tailstock tool 32c on the tool main spindle 18 together with the tool holder 42 using the exchange arm 50 of the exchange mechanism 28 in the storage unit 26 (see Fig. 5). At the same time, the exchange arm 50 mounts a tailstock tool 32c, which is to be newly mounted on the tailstock 30, onto the main tool spindle 18.

[0058] Once the tailstock tool 32c is newly mounted on the main tool spindle 18, the controller 39 moves the main tool spindle 18 into the movement range of the internal robot 24 and drives the internal robot 24 to mount the tailstock tool 32c on the main tool spindle 18 on the tailstock 30. This completes the exchange of the tailstock tools 32c between the tailstock 30 and the storage unit 26.

[0059] As apparent from the above description, in this embodiment, tools (the tailstock tools 32c) are also exchanged via the tool main spindle 18. This structure enables automatic tool exchange also with respect to the tailstock 30 (the first holder) located away from the storage unit 26, while preventing an increase in cost and an increase in size.

[0060] Although in the above description, the exchange mechanism 28 and the storage unit 26 are arranged inside the processing chamber 12, they may be arranged outside the processing chamber 12. Fig. 15 is a schematic plan view of such a machine tool 10. In the example shown in Fig.As illustrated in Figure 15, the storage unit 26 is arranged outside the processing chamber 12. In the storage unit 26, a plurality of tools 32 are held such that they are movable along an annular rail 26a. The exchange mechanism 28 is arranged outside the processing chamber 12 and includes a robot 60 with a rotating arm 62. The rotating arm 62 rotates about a predetermined axis to thereby access both the storage unit 26 and the processing chamber 12. When exchanging the tools 32, the lower tool post 20, which is arranged inside the processing chamber 12, moves to the vicinity of the rotating arm 62.

[0061] The structures described above are merely examples, and structures other than a structure for exchanging the tools 32 between the first holding device and the storage unit 26 via the internal robot 24, the second holding device, and the exchange mechanism 28 can be modified as desired. For example, the second holding device may be any holding device that holds the tool 32, and is not limited to the tool main spindle 18. In the case where an existing ATC is used as the exchange mechanism 28, the second holding device may be a cutting tool holding device that holds the cutting tool 32a to be exchanged by the ATC.Furthermore, although a cleaning mechanism (the end effector 40) mounted on the internal robot 24 is used to clean the tool 32 held by the first holding device, such a cleaning mechanism may be provided separately from the internal robot 24. For example, a mechanism for supplying cutting oil and air to the machining site, with which the machine tool 10 is generally equipped, may be used as a cleaning mechanism. List of reference symbols 10 machine tools, 12 processing chamber, 14 front door, 16 workpiece main spindle, 18 main tool spindle, 20 lower tool stand, 22 revolvers, 24 internal robots, 26 storage units, 27 flap, 28 Exchange mechanism, 30 tailstock, 32 tools, 32a cutting tool, 32b clamping head claw, 32c tailstock tool, 34 Main spindle end, 38 robot arm, 39 control device, 40 end effector, 42 tool holders, 42e intervention unit, 42m machine connector, 42t tool connector, 48 tool magazine, 50 exchange arm, 52 engagement hooks, 56 locking hole, 60 robots, 62 rotating arm

Claims

[1] Machine tool (10) for machining a workpiece by means of a cutting tool (32a), the machine tool (10) comprising: a first holding device for holding a tool (32, 32a, 32b, 32c); a second holding device for holding the tool (32, 32a, 32b, 32c); a storage unit (26) for storing one or more tools (32, 32a, 32b, 32c); an exchange mechanism (28) for exchanging the tools (32, 32a, 32b, 32c) between the second holding device and the storage unit (26), wherein the exchange mechanism (28) cannot directly access the first holding device; a robot (24) for exchanging the tools (32, 32a, 32b, 32c) between the first holding device and the second holding device; and a control device (39) for controlling the driving of the first holding device, the second holding device, the exchange mechanism (28) and the robot (24), wherein the control device (39) carries out the control in such a way that the tools (32, 32a, 32b, 32c) are exchanged between the first holding device and the storage unit (26) via the robot (24), the second holding device and the exchange mechanism (28), characterized by that the first holding device and the second holding device are installed in a processing chamber (12), wherein the second holding device is a tool main spindle (18) or a tool stand (20) which holds a cutting tool (32a) as the tool (32, 32a, 32b, 32c), and the exchange mechanism (28) is an automatic tool changing device which includes an exchange arm (50) and / or a robot arm. [2] The machine tool (10) according to claim 1, wherein the first holding device is a tool stand (20) holding a cutting tool (32a) as the tool (32). [3] A machine tool (10) according to any one of claims 1 or 2, wherein the first holding device is a workpiece main spindle (16) holding a clamping head claw (32b) as the tool (32). [4] The machine tool (10) according to any one of claims 1 to 3, wherein the first holding device is a tailstock (30) holding a tailstock tool (32c) as the tool (32). [5] Machine tool (10) according to one of claims 1 to 4, wherein the second holding device holds a tool (32, 32a, 32b, 32c) to be held on the first holding device via a tool connector (42t) having the same shape as a tool holder of the first holding device and a machine connector (42m) adapted to be connected to a tool holder of the second holding device. [6] A machine tool (10) according to any one of claims 1 to 5, further comprising a cleaning mechanism for cleaning around the tool (32, 32a, 32b, 32c) held on the first holding device, wherein the control device (39) causes the cleaning mechanism to clean around the tool (32, 32a, 32b, 32c) before exchanging the tools (32, 32a, 32b, 32c) between the first holding device and the storage unit (26). [7] Machine tool (10) according to one of claims 1 to 6, wherein the robot (24) includes a main body and one or more end effectors (40) interchangeably mounted on the main body. [8] The machine tool (10) of claim 7, wherein the end effector (40) to be mounted on the robot (24) is selected from a group including an end effector (40) for gripping an object and an end effector (40) for cleaning around the tool (32, 32a, 32b, 32c) held on the first holding device.

Images