Machine tool for machining workpieces and tool changing procedures for such a machine tool

Abstract

The present invention relates to a machine tool and a tool changing method. The machine tool has a tool changing gripper 14, which has two gripper arms 29 and 30 rotatable about a common axis of rotation D. The gripper arms 29 and 30 are arranged at an acute angle (less than 90°) to each other. The acute-angled arrangement of the gripper arms allows for particularly compact machine tool configurations. The control device for the tool changing gripper 14 is configured to control the tool changing gripper 14 such that the range of motion is changed depending on which of the two gripper couplings 34 and 35 is occupied by a tool, in order to keep it outside the projection of the interference contour 38 of the bearing block 21.In another independent aspect, the tool magazine 14 is arranged at an angle to the axis of rotation D in order to position the staging position 33 and the changeover position 32, into which two tools 27a and 27b are placed during a tool change operation, closer to each other. This allows the swing radius of the tool change gripper 14 to be reduced when rotating about the axis of rotation D.

Description

[0001] The invention relates to a machine tool, which is particularly designed for machining workpieces. Furthermore, the invention relates to a method for changing tools between a work spindle and a tool magazine.

[0002] Machine tools, such as numerically controlled (computerized numerical control; CNC) machining centers, are already known in various embodiments from the prior art. In such machine tools, workpieces are typically machined in several machining steps using multiple, and in particular different, tools that can be successively loaded by a work spindle. For example, a tool change may be necessary due to wear of the tool being loaded by the work spindle. Conversely, different machining steps may also require different tool types. The tools used in machining the workpiece are typically provided by a tool magazine. Tools that are not currently being used for machining the workpiece are stored in a tool magazine.The tool change process between a previously used tool and a tool to be used typically proceeds as follows: the work spindle with the previously used tool is moved into a changeover position, in which a tool changer associated with the tool magazine picks up the previously used tool from the work spindle and replaces it with the new tool to be used from the tool magazine. Tool changers with a gripper arm rotatably driven about a rotary axis are known from the prior art. At each end of the gripper arm, diametrically opposed gripper couplings are arranged, which are open in a circumferential direction, for example, clockwise or counterclockwise. The tool change is effected by rotating the gripper arm by 180°.

[0003] German patent DE 10 2005 003 220 B4 describes a tool changing device comprising a tool magazine with a double gripper and a drive and positioning device associated with the double gripper. The tool changing process described therein involves two tool holders of the tool magazine and the work spindle. In a first step, the double gripper removes the tool from the tool holder and the work spindle, then pivots and inserts the tool removed from the tool holder into the work spindle. It then inserts the tool removed from the work spindle into a subsequent tool holder. With the double gripper described therein, adjacent tool holders of the tool magazine can be operated without having to move the tool magazine.The double gripper described there has two gripper arms rotatable about a common axis of rotation, which are at an angle to each other, the apex of which lies on the axis of rotation and which is between 90° and 180°.

[0004] US Patent 2024 / 0058880 A1 also describes a tool changer for changing tools in a machine tool, which has a support structure on which a lifting carriage is guided along a vertical stroke direction. A pivot arm is mounted on the lifting carriage so as to pivot about a vertical pivot axis. Several vertically stacked tool holders form a tool magazine.

[0005] With tool changing devices known from the prior art, the interference circle described by the tool changing gripper and the held tools is particularly problematic in compact machine tools. For example, especially in multi-axis machine tools, such as 3-, 4- or 5-axis machine tools, the bearing or drive of the workpiece table can pose a collision hazard for the tools held by the tool changer during the changing process.

[0006] Based on this, the object of the invention is to provide an improved machine tool with an improved tool-changing gripper, which in particular enables a particularly compact design and at the same time a tool-changing process that is as quick and easy as possible.

[0007] The object of the invention is solved by the machine tool according to claim 1 and the tool changing method according to claim 14.

[0008] The machine tool according to the invention comprises at least one work spindle, a workpiece table, a tool magazine, a tool changer, and a control unit. The at least one work spindle has a tool holding device connected to a rotary drive unit and configured for rotation about a machining axis (C-axis) of the work spindle. The work spindle is preferably movable linearly (translationally) in at least two, and in particular at least three, mutually orthogonal directions. For example, the work spindle is movable translationally along a first horizontal axis (X-axis), along a vertical axis (Y-direction), and along a second horizontal direction (Z-axis) orthogonal to the first horizontal axis (X-axis). The X-, Y-, and Z-axes are preferably orthogonal to each other and form a coordinate system.The machining axis, C-axis, preferably runs parallel to the Z-axis.

[0009] The workpiece table comprises a carrier on which at least one workpiece and / or a workpiece pallet with at least one workpiece arranged thereon can be clamped, and at least one bearing block to which a interference contour is assigned. The interference contour of the bearing block is a contour in which the bearing block, preferably together with the carrier and workpiece and / or workpiece pallet, is movable, i.e., rotatably and translationally. The workpiece table can be designed to be movable along the Z-axis. Furthermore, the workpiece table can have at least one, but preferably at least two, axes along which the workpiece can be moved by means of the workpiece table. For example, the carrier is pivotable about a carrier axis (A-axis). The workpiece table has at least one bearing block in which the drive for the pivoting movement about the carrier axis (A-axis) and the bearing of the carrier about the A-axis are housed.A rotary table can also be mounted on the support, defining a rotary table axis (B-axis) around which the rotary table can rotate. Workpiece pallets with workpieces arranged on them, or even workpieces directly, can be clamped onto the rotary table, allowing the workpiece to be rotated around the B-axis by the rotary table.

[0010] The tool magazine is designed to hold and store a large number of tools and to provide one of the tools at a specific staging position and in a specific staging direction. The tool magazine can, for example, be a chain magazine.

[0011] The tool-changing gripper has two gripper arms that are rotatable about a common axis of rotation (D-axis) and rigidly connected to each other. The rigid connection of the two gripper arms couples their movement. Each gripper arm is equipped with a gripper coupling for receiving a tool. The gripper arms are arranged at a predetermined (acute) angle to each other, less than 90°, with the apex of this angle lying on the common axis of rotation. The gripper couplings are located, in particular, on a common radius around the axis of rotation (D-axis). The gripper couplings are preferably oriented such that they are open in the tangential direction. The gripper couplings are preferably identical.The tool change gripper is specifically designed to perform a lifting movement axially to the axis of rotation (D-axis) in order to pick up and / or deliver tools located in a staging position and / or a change position from the work spindle or a staging device of the tool magazine. The tool change gripper can, for example, be controllably moved between a first lifting position and a second lifting position. The tool change gripper is specifically designed to perform rotary and lifting movements independently of each other. The gripper arms can be arranged so close together, particularly when the angles between them are small, that they form a single gripper in which there is no gap between the gripper arms, but rather two gripper arm sections instead of two separate gripper arms. The gripper arms or the gripper itself can be monolithic.

[0012] The control device is designed to control the tool change gripper in such a way that a tool picked up by the tool holding device of the work spindle and moved into a change position is replaced by a new tool provided in the staging position, wherein at least the gripper couplings occupied with a tool are always outside an area which is a projection of the interference contour onto the plane of motion of the gripper arms.

[0013] This allows for a particularly compact arrangement of the machine tool. The acute angle between the gripper arms makes it possible to position the staging position of the new tool closer to the changeover position of the tool already in use.

[0014] A special feature of the present invention is that at least the gripper couplings carrying a tool are always located outside an area that is a projection of the interference contour onto the plane of motion of the gripper arms. This makes it possible to position the bearing block of the workpiece table, in particular the bearing block of the carrier in which the bearing and the drive for the carrier axis (A-axis) are housed, closer to the tool magazine in the Z-direction. The tool-changing gripper designed in this way, in conjunction with the control unit, thus offers a tool-changing solution especially for particularly compact machine tools.

[0015] The control unit is preferably configured to define a range of motion for the tool changer gripper depending on which of the gripper couplings are occupied by a tool. This enables, on the one hand, the largest possible range of motion for the tool changer gripper and, on the other hand, the lowest possible risk of collision between the tools picked up by the tool changer gripper and other components of the machine tool, such as, in particular, the bearing block of the workpiece table.

[0016] The range of motion for the gripper arms is defined in particular as follows: - that the gripper couplings are movable on a (complete) circle around the axis of rotation when both gripper arms are unoccupied; - that the gripper couplings are movable on a partial arc of the circle around the axis of rotation if at least one of the two gripper couplings is occupied by a tool.

[0017] Preferably, the (two) limits of the movement range are selected such that the gripper coupling(s) on the gripper arms lie (completely) outside the projection of the interference contour onto the circular plane in which the gripper arms move. The limits can be defined, for example, for different tool types, which differ particularly in their dimensions. For instance, fixed limit values ​​for the limits can be stored in a memory structure of the control unit. Depending on which tool type is held by which gripper coupling, the limits can be selected.

[0018] The predetermined (acute) angle between the gripper arms is preferably in the range between 20° and 80°, particularly between 30° and 70° and especially preferably between 40° and 60°.

[0019] The gripper couplings preferably have receiving openings which are oriented in the circumferential direction, wherein the receiving openings of the gripper couplings are arranged such that both are located on opposite sides of the gripper arms or one of the two is located on a side facing the other gripper arm.

[0020] The machine tool preferably has a tool handling area in which tools can be supplied from and returned to the tool magazine. Furthermore, the machine tool preferably has a work area separate from the tool handling area in which the workpiece is machined using the tool held by the work spindle. The machine tool may also have the following features: - a partition door that can be opened and closed, separating the tool handling area from the work area when closed; - a cleaning facility located in the tool handling area and designed for cleaning tools; and / or - A tool inspection device located in the tool handling area and designed for the (optical or tactile) inspection of tools. This allows preparatory and follow-up operations for cleaning and checking the tools to be carried out concurrently with the machining process, i.e., while the workpiece is being machined using the tool held by the work spindle. In particular, the tool changer is designed to perform preparatory and / or follow-up operations, such as providing, cleaning, and / or inspecting tools, concurrently with the machining process, even with the separating door in the tool handling area closed. Because these operations can be performed concurrently with the machining process, the downtime of the work spindle during tool changes can be reduced.

[0021] It is preferred that the provisioning position and the changeover position are arranged on the circle around the axis of rotation (diametrically opposite each other). A cleaning position, in which a tool can be cleaned using the cleaning device, and / or a tool inspection position, in which a tool can be inspected using the tool inspection device, can also be arranged on the circle around the axis of rotation between the two positions.

[0022] In particular, a first angle exists between the staging position and the tool inspection position, the apex of which lies on the axis of rotation. The first angle is, in particular, at least substantially, 90°. Preferably, a second angle exists between the staging position and the cleaning position, the apex of which also lies on the axis of rotation. The second angle is, in particular, the difference between the first angle and the predetermined angle between the gripper arms.

[0023] The tool magazine can, for example, be designed as a chain magazine. The tool magazine preferably has a staging device that is configured to move a new tool from the tool magazine into the staging position and orientation.

[0024] In addition to or independently of the specific design of the tool changer gripper, the tool magazine of the machine tool according to the invention is arranged laterally next to the work spindle and at an angle to the work spindle, in particular to the axis of rotation (D-axis). By angling the tool magazine to the axis of rotation, the machine tool can be designed such that the tool magazine is positioned closer to the tool changer gripper at the location of the gripper's provisioning position, thereby achieving a more compact overall arrangement of the machine tool. Furthermore, this can result in a smaller tool change rotation circle for the tool changer gripper, on which the tools involved in the tool change rotate during the change process.This allows for faster tool change movements and lower forces due to the shorter lever arm on the drives and bearings of the tool change gripper.

[0025] This allows the staging position to be brought closer to the changeover position, resulting in an even more compact overall arrangement of the machine tool.

[0026] It is preferred that, in the top view, the magazine angle between the tool magazine and the axis of rotation (D-axis) is 0°. The magazine angle can also be 90° or between 5° and 85°.

[0027] In a preferred embodiment, the tool magazine is dimensioned such that the ratio between its height and width is between 0.5 and 1.0. Preferably, the ratio is greater than or equal to 1.0, and in particular, it is greater than 2.0 or 3.0. The tool magazine is thus taller than it is wide, which allows the overall machine tool assembly, especially its lateral dimensions, to be kept compact.

[0028] Preferably, the tools held in the tool magazine are oriented in a storage orientation. The staging device can be configured to move the new tool from the storage orientation to the staging orientation.

[0029] Furthermore, the object of the invention is solved by a tool changing method of the machine tool described above, wherein the tool changing method comprises the following steps: - Deploying a new tool to the deployment position; - Rotating the gripper arms around the axis of rotation in such a way that the first gripper coupling is brought into the provision position and picking up the provided new tool with the first gripper coupling; - Providing the previously used tool in the changeover position using the work spindle; - (first) rotation of the gripper arms around the axis of rotation such that the second gripper coupling is brought into the change position and picking up the previously used tool with the second gripper coupling; - (second) rotation of the gripper arms around the axis of rotation such that the first gripper coupling is brought into the change position and the new tool is picked up by the work spindle; - Moving the work spindle with the newly acquired tool from the changeover position; - (third) Rotating the gripper arms around the axis of rotation in such a way that the second gripper coupling is brought into the ready position.

[0030] The individual steps of the tool change procedure described above are preferably carried out in the sequence specified above. Picking up tools with the tool change gripper from the supply unit and / or the work spindle, as well as releasing tools with the tool change gripper to the supply unit and / or the work spindle, particularly includes a translational stroke movement of the tool change gripper axially to the axis of rotation (D-axis). Tools located in the supply position and / or in the change position can be picked up from and / or released from the gripper couplings of the tool change gripper by this translational stroke movement. The first rotation is preferably counterclockwise (in the mathematically positive direction of rotation). The second rotation is preferably clockwise (in the mathematically negative direction of rotation).The third rotation preferably occurs counterclockwise (in the mathematically positive direction of rotation). The rotational movements of the gripper arms are all relatively short, which minimizes the travel distances during tool changes and thus reduces tool change time.

[0031] It is preferred that the first gripper coupling is moved into the cleaning position between the first rotation and the second rotation about the axis of rotation, whereby the new tool is cleaned by means of the cleaning device.

[0032] Preferably, the second gripper coupling is moved into the tool control position between the third and fourth rotations around the axis of rotation, whereby the tool already used is checked by means of the tool control device.

[0033] The features and advantages described in relation to the machine tool according to the invention are also applicable to the tool changing method according to the invention.

[0034] Further details, advantageous embodiments, or specific aspects of the invention will become apparent from the drawings, the description, and the dependent claims. These show: Fig. 1 a schematic perspective view of an embodiment of the machine tool according to the invention; Fig. 2 a view of an embodiment of the tool change gripper; Fig. 3 a view of another embodiment of the tool change gripper; Fig. 4 a top view of an embodiment of the machine tool; Fig. 5 a top view of another embodiment of the machine tool; Fig. 6 a side view of the in Fig. 5 illustrated embodiment of the machine tool; Fig. 7 a side view of the in Fig. 4 illustrated embodiment of the machine tool; Fig. 8-19 an illustration of a tool change using the in Fig. 2 interchangeable grippers shown; as well as Fig. 20-25 an illustration of a tool change process with the tool change gripper according to Fig. 3.

[0035] Fig. Figure 1 shows an embodiment of the machine tool 10 according to the invention. The in Fig. The machine tool 10 shown is designed as a machining center. The machine tool 10 has a work spindle 11, a workpiece table 12, a tool magazine 13, and a tool change gripper 14.

[0036] The work spindle 11 has a tool holding device 15 which is connected to a rotary drive device 16 and is set up for the rotary drive of the work spindle 11 about a machining axis C (C-axis).

[0037] In the Fig. In the example shown, the work spindle is part of a machining tower 17, which is arranged on a machine frame 18. The machining tower 17 is arranged on a movable slide 19 such that the work spindle 11 can be moved along two axes arranged orthogonally to each other, namely the Z and X axes, and along a vertical axis, the Y axis. Unlike in Fig. As shown in Figure 1, the work spindle 11 can also be moved only along the X and Y axes.

[0038] The workpiece table 12, which is in Fig. Figure 1 shows an asymmetrically mounted workpiece table 12. The workpiece table 12 has a support 20 which is pivotable about a horizontally arranged support axis A. For support and drive, the workpiece table 12 has a bearing block 21 which allows the support 20 to pivot about the A-axis. The in Fig. The workpiece table 12 shown in Figure 1 also has a rotary table 22 on which a workpiece pallet 23 can be clamped. The rotary table 22 is rotatably mounted on the support 20 about a rotary table axis B such that the workpiece pallet 23, with a workpiece clamped on it (not shown), is rotatable about the rotary table axis B. The workpiece table 12 is located in the Fig. The example shown in point 1 is not depicted as linearly movable. That is, in the case of the one shown in Fig. In the example shown, the workpiece table cannot be moved translationally along the Z-axis. Unlike in Fig. As shown in Figure 1, the workpiece table can also be designed to be linearly (translationally) movable. Furthermore, unlike in Figure 1, it can also be designed to be linearly (translationally) movable. Fig. As shown in Figure 1, the workpiece table 12 also has a counter bearing arranged such that the rotary table 22 with the workpiece pallet 23 mounted on it is enclosed by the bearing block 21 and the counter bearing arranged opposite it. The support 20 spans the space between the bearing block 21 and the counter bearing.

[0039] In Fig. Figure 1 also shows a pallet changing device 24, which is set up for changing the workpiece pallets 23. By way of example, the pallet changing device 24 has a pallet changing carrier 25, which is rotatable about a vertically oriented pallet changing axis W and can be moved upwards or downwards in a lifting motion. The pallet changing carrier 25 in Fig. 1 has two pallet holders 26, which are arranged diametrically opposite the pallet change axis W. For a pallet change, the pallet change carrier can, for example, be lifted upwards to receive the two workpiece pallets 23 to be exchanged and rotated by 180° to exchange the position of the two workpiece pallets.

[0040] The in Fig. The tool magazine 13 shown is designed as an example of a chain magazine. The tool magazine 13 is arranged next to the work spindle 11, next to the machining turret 17. The tool magazine 13 is located in the Fig. In the example shown, the machining tower 13, the workpiece table 12, and the pallet changing device 24 are arranged on the same machine frame 18 as the machining tower 13. Unlike in Fig. As shown in Figure 1, the individual units of the machine tool can also be arranged on different machine frames.

[0041] The tool change gripper 14 is arranged between the tool magazine 13 and the machining spindle 11. The tools 27, which are held by the tool magazine 13, are oriented such that they can be moved along a magazine trajectory on the chain. The tools 27 are oriented in a bearing orientation when held by the tool magazine 13. The bearing orientation is at least substantially horizontal. Fig. 1 The tool magazine 13 is arranged transversely to the machining axis C (C-axis). In the Fig. In the example shown, the angle between the bearing orientation of the tools 27, which are held by the tool magazine 13, and the work spindle 11 is at least substantially 90°; the bearing orientation runs parallel to the X-axis.

[0042] The tool magazine 13 has a staging device 28 which is configured to bring at least one of the tools 27 from the tool magazine 13 into a staging position 33 and into the staging orientation that runs parallel to the axis of rotation D about which the tool change gripper 14 is rotatable. Fig. 1. The staging device 28 rotates a tool 27a to be used by 90°. The staging device 28 can also – unlike in Fig. 1. The tool 27a to be used is shown rotated by an angle less than 90°, as shown in the Fig. 4 and Fig. 5 is shown as an example, e.g. if the tool magazine 13 and / or the bearing orientations of the tools 27 held by the tool magazine 13 are aligned at a different angle to the axis of rotation D of the tool change gripper 14.

[0043] The tool-changing gripper 14 has two gripper arms 29 and 30 that can be rotated about a common axis of rotation D. The two gripper arms 29 and 30 are rigidly connected to each other so that they can be moved together, in a coupled motion, about the axis of rotation D. Gripper couplings 34 and 35 for receiving a tool are provided at each end region of the gripper arms 29 and 30. The gripper couplings 34 and 35 are connected with respect to the Fig. 2 and Fig. 3 described in detail.

[0044] In the Fig. In the example shown, the gripper arms 29, 30 are preferably oriented upwards and remain at least substantially within this range of motion during the changeover process. This is particularly true when the gripper couplings 34, 35 are fitted with tools 27.

[0045] The machine tool 10 in Fig. 1 also has a control device 31 which is configured to control the tool change gripper 14 in such a way that a tool 27b picked up by the tool holding device 15 and brought into a change position 32 by means of the work spindle 11 is replaced by a new tool 27a provided in the staging position 33.

[0046] Fig. Figure 2 shows an example of the tool-changing gripper 14. The tool-changing gripper has a first gripper arm 29 and a second gripper arm 30, which are arranged at a (peripheral) predetermined angle α, the apex of which lies on the axis of rotation D. The predetermined angle α is less than 90°. Because an acute angle α is provided between the gripper arms 29 and 30, the work spindle 11, the workpiece table 12, and the tool magazine 13 with tool-changing gripper 14 can be arranged in a particularly compact manner, without any interfering contour 38 of the workpiece table 12, in particular the bearing block 21 of the workpiece table 12, obstructing the tool-changing process and potentially causing a collision.

[0047] Fig. Figure 2 shows an example of the tool-changing gripper 14. The tool-changing gripper 14 has a first gripper arm 29 and a second gripper arm 30, which extend radially from the axis of rotation D. The first gripper arm 29 and the second gripper arm 30 are arranged such that there is a predetermined angle α between them, which is less than 90°. In the Fig. In the example shown, the acute angle is approximately 45°. A first gripper coupling 34 is arranged at one end section of the first gripper arm 29, and a second gripper coupling 35 is arranged at one end section of the second gripper arm 30. The first gripper coupling 34 and the second gripper coupling 35 each have a receptacle 36 designed to receive the shank of a tool 27. The receptacles 36 are open on opposite sides of the gripper arms 29 and 30. Each of the gripper couplings 34 and 35 also has a locking finger 37, which holds a tool 27, whose shank is arranged in the receptacle 36, in the receptacle 36. The first gripper arm 29 and the second gripper arm 30 can be monolithic.In any case, the two gripper arms 29 and 30 are rigidly connected to each other, so that a movement of the tool-changing gripper 14 about the axis of rotation D results in both gripper arms 29 and 30 being moved simultaneously. Unlike in . Fig. As shown in Figure 2, there can also be no recess between the gripper arms 29 and 30, so that the two gripper arms 29 and 30 are designed as gripper arm sections of a single gripper arm. The tool-changing gripper 14 can be rotated about the axis of rotation D such that one of the two gripper couplings 34 and 35 is in a provision position 33 or in a change position 32.

[0048] Fig. Figure 3 shows another example of the tool-changing gripper 14. For the one in Fig. The tool change gripper 14 shown in section 3 is the same as previously stated with reference to Fig. 2. Said accordingly. The one in Fig. The 3 shown interchangeable gripper 14 differs from the one in Fig. The interchangeable gripper shown in Figure 2 is modified by the fact that the receptacle 36 of the second gripper coupling 35 is arranged on the second gripper arm 30 on a side facing the first gripper arm 29. This results in the tool change process of a Fig. The tool change gripper shown in the 3 differs from that of one in Fig. The tool change gripper shown in section 2 can be distinguished. The phases of the tool change process, in which the sequence of the tool change gripper 14 differs, are described below. Fig. 3 of the tool change gripper 14 from Fig. 2 distinguishes, is in the Fig. 20 to 25 are shown.

[0049] In Fig. 4 is a top view of the Fig. Machine tool 10 is shown in section 1. In the section on Fig. In the four examples of the machine tool 10 shown, the tool magazine 13 is arranged laterally next to the work spindle 11 and also laterally next to the machining turret 17. The tool magazine 13 is arranged at an angle to the axis of rotation D of the tool change gripper 14. The tool magazine 13 has a longitudinal axis L along which it extends. The longitudinal axis L of the tool magazine extends at least substantially horizontally. A predetermined magazine angle γ exists between the longitudinal axis L of the tool magazine 13 and the axis of rotation D. The predetermined magazine angle γ is shown in the Fig. The example shown in section 4 is approximately 30°.

[0050] The tools 27 held by the tool magazine 13 are stored in a bearing orientation on the side of the tool magazine facing away from the machining tower 17. A tool 27a to be used is transferred by the staging device 28 from the bearing orientation to the staging position 33 and the staging orientation. To transfer the tool 27a to be used, it is rotated about a staging axis 46. The angle overcome in this process is 90°, from which the magazine angle γ is subtracted.

[0051] The previously used tool 27b is located in Fig. 4 in the changeover position 32. The tool change gripper 14 is arranged between the changeover position 32 and the provision position 33.

[0052] In Fig. Figure 4 also shows a interference contour 38 of the bearing block 21 of the workpiece table 12. The interference contour 38 of the bearing block 21 is located below the plane of representation in which the axis of rotation D is arranged.

[0053] Fig. Figure 5 shows another example of machine tool 10. For the one in Fig. The example shown in point 5 applies to this as well. Fig. 4. With reference to the reference marks, what has been said accordingly. The example from Fig. 5 differs from the example from Fig. 4 by the fact that the tool magazine 13 has a smaller width than the tool magazine 13 made of Fig. 4.

[0054] Fig. Figure 6 shows a side view of an example of the tool magazine 13. The tool magazine 13 has a height h and a width b. And in the Fig. In the example shown in Figure 6, the height h is greater than the width b of the tool magazine 13. A ratio between the height h and the width b of the tool magazine 13 is given in the example shown in Figure 6. Fig. The example shown in 6 is greater than 2.

[0055] Fig. Figure 7 shows another example of a tool magazine 13. In contrast to the one in Fig. In the example shown in Figure 6, the width b of the tool magazine 13 is greater than the height h of the tool magazine. The ratio between the height h and the width b is less than 0.5 in this example.

[0056] In the Fig. 8 to 19 is the tool change process for the in Fig. 2 illustrated tool change gripper 14.

[0057] The tool change gripper 14 is arranged in a tool handling area 39, which can be separated from the work area 40 by means of an opening and closing partition door 41. The tool magazine 13 is also assigned to the tool handling area 39. The interference contour 38 of the bearing block 21 is also shown in the tool handling area 39. This is projected onto the plane in which the tool change gripper 14 moves about the axis of rotation D. The previously used tool 27b was picked up by the work spindle 11. The tool 27a to be used in the next machining step was brought into the staging position 33 and into the staging orientation by means of the staging device 28, as shown in Fig. 9 shown.

[0058] As in Fig. As shown in Figure 9, the tool 27a to be used was pivoted about the staging axis 46 by means of the staging device 28, thereby bringing it into the staging position 33 and into the staging orientation. The staging device 28 is designed as a pivoting lever with a tool holder that can be pivoted about the staging axis 46.

[0059] The tool-changing gripper 14 is then rotated about the axis of rotation D to pick up the new tool 27a with the first gripper coupling 34, which is arranged on the first gripper arm 29. The tool-changing gripper is pivoted counterclockwise (in the mathematically positive direction of rotation) about the axis of rotation D so that the first gripper coupling 34 is brought into the staging position 33. This is in Fig. Figure 10 illustrates this. To pick up the tool 27a to be used with the first gripper coupling 34, the tool changer gripper 14 performs a translational stroke movement axially to the axis of rotation D from a first stroke position to a second stroke position. The tool changer gripper 14, with the tool 27a to be used arranged in the first gripper coupling 34, can then be moved out of the staging position 33. The second stroke position of the tool changer gripper 14 is maintained until the tool changer gripper 14, and in particular the first gripper coupling 34, is located outside the vicinity of the staging position 33. After the tool 27a to be used has been picked up by the first gripper coupling 34, the tool changer gripper 14 is rotated clockwise (in the mathematically negative direction of rotation) along the axis of rotation D to a position in which the first gripper coupling 34 is in a cleaning position 43.This is in . Fig. Figure 11 illustrates this. During and / or after rotation, the tool change gripper 14 can be moved from the second stroke position back to the first stroke position. A cleaning device is provided to clean a tool that has been moved by the tool change gripper 14 into the cleaning position 43. After and / or during the cleaning process, the opening and closing partition door 41 is opened so that the tool change gripper 14 can continue to rotate about the axis of rotation. The second (free) gripper coupling 35 is moved into the change position 32. This is shown in Fig. Figure 12 illustrates this. The previously used tool 27b can be moved into the change position 32 by means of the work spindle 11 either before, simultaneously with, or after the change. To pick up the previously used tool 27b with the second gripper coupling 35, the tool change gripper 14 again performs a translational stroke movement axially to the axis of rotation D, so that the tool change gripper 14 is moved from the first stroke position to the second stroke position.

[0060] Subsequently, the tool-changing gripper 14 can be rotated further about the axis of rotation D in a clockwise direction (in the mathematically negative direction of rotation) such that the tool 27a to be used, which is held by the first gripper coupling 34, is in the change position 32, as shown in Fig. Figure 13 illustrates this. To transfer the tool 27a to be used from the first gripper coupling 34 to the work spindle, the tool changer gripper 14 performs a translational stroke movement axially to the axis of rotation D, so that the tool changer gripper 14 is moved from the second stroke position to the first stroke position. The tool changer gripper 14 is then rotated clockwise (in the mathematically negative direction of rotation) about the axis of rotation D so that the work spindle 11, with the tool 27a to be used now in place, can be moved out of the path of the tool changer gripper 14, as shown in Figure 13. Fig. 14 and Fig. Figure 15 shows that the tool change gripper can then be rotated counterclockwise (in a mathematically positive direction) about the axis of rotation D so that it is (completely) located in the tool handling space 39, as shown in Figure 15. Fig. Figure 16 shows the opening and closing partition door 41, which can then be closed again. Fig. 16 The tool change gripper 14 is aligned such that the second gripper coupling 35, with the previously used tool 27b it holds, is in a tool inspection position 44. A tool 27 in the tool inspection position 44 can be inspected by means of a tool inspection device 45, for example optically, to detect tool wear, tool breakage, or other defects.

[0061] In the Fig. 17, Fig. 18 and Fig. Figure 19 also shows how the previously used tool 27b is moved to the staging position 33. To transfer the previously used tool 27b from the second gripper coupling 35 to the staging device 28, the tool change gripper 14 is moved from the first stroke position to the second stroke position before the second gripper coupling 35 reaches the staging position 33. When the second gripper coupling 35 is in the staging position 33, the tool change gripper 14 can be moved from the second stroke position to the first stroke position to transfer the previously used tool 27b to the staging device 28. The previously used tool 27b is then picked up by the staging device 28.The tool-changing gripper 14 is rotated further counterclockwise (in the mathematically positive direction) about the axis of rotation D, so that the previously used tool 27b is brought into the storage orientation by the supply device 28, which rotates the previously used tool 27b about the supply axis 46, in order to be picked up by the tool magazine 13. The gripper arms 29 and 30 of the tool-changing gripper 14 can then be located within a range of motion if the gripper couplings 34 and 35 assigned to the respective gripper arm are not occupied by a tool.

[0062] In the Fig. 17, Fig. 18 and Fig. For example, the first gripper arm 29 of the tool-changing gripper 14 is arranged within the projection of the interference contour 38 of the bearing block 21. In the Fig. 20, Fig. 21, Fig. 22, Fig. 23, Fig. 24 and Fig. Figure 25 shows the tool change sequence for the embodiment of the tool change gripper 14, in which the second gripper coupling 25 is open in the direction of the first gripper coupling 34, as shown in Fig. Figure 3. For the embodiment shown here, the above applies accordingly with reference to the reference numerals. The one in the Fig. The tool change operation shown in Figures 20-25 differs from the previous tool change operation in that the tool change gripper 14 passes over the change position 32, so that the previously used tool 27b can be brought into the tool change position 32 by means of the work spindle 11 without the rear of the second gripper arm 30 obstructing the work spindle 11. Subsequently, the tool 27a to be used, which is held in the first gripper coupling 34, is brought into the change position 32 (see Figure 20-25). Fig. 23). After the tool 27a to be used has been picked up by the work spindle 11, it can be moved out of the flight circle of the tool change gripper 11. The tool change gripper 14 can now be rotated back about the axis of rotation D counterclockwise (in the mathematically positive direction of rotation) such that the tool 27b picked up by the second gripper coupling 35 is in the tool control position 44 (see Fig. 25). The opening and closing partition door 41 can then be closed to separate the tool handling room 39 from the work room 40.

[0063] The present invention relates to a machine tool and a tool changing method. The machine tool has a tool changing gripper 14, which has two gripper arms 29 and 30 rotatable about a common axis of rotation D. The gripper arms 29 and 30 are arranged at an acute angle (less than 90°) to each other. The acute-angled arrangement of the gripper arms allows for particularly compact machine tool configurations. The control device for the tool changing gripper 14 is configured to control the tool changing gripper 14 such that the range of motion is changed depending on which of the two gripper couplings 34 and 35 is occupied by a tool, in order to keep it outside the projection of the interference contour 38 of the bearing block 21.In another independent aspect, the tool magazine 14 is arranged at an angle to the axis of rotation D in order to position the staging position 33 and the changeover position 32, into which two tools 27a and 27b are placed during a tool change operation, closer to each other. This allows the swing radius of the tool change gripper 14 to be reduced when rotating about the axis of rotation D. Reference symbol: 10 machine tool 11 work spindle 12 Workpiece table 13 Tool magazine 14 tool change grippers 15 Tool holding device 16 Rotary drive unit 17 processing towers 18 machine frames 19 sleds 20 carriers 21 Bearing block of the support 22 Rotary table 23 workpiece pallet 24 pallet changing device 25 pallet changers 26 pallet recordings 27 tools 27a new tool to be used 27b previously used tool 28 Provisioning facility 29 first gripper arm 30 second gripper arm 31 Control unit 32 Change position 33 Deployment position 34 First gripper coupling 35 Second gripper coupling 36. Mounting the gripper coupling 37 locking fingers 38 Interference contour of the bearing block 39 Tool handling room 40 workspace 41 opening and closing partition doors 42 Provisioning axis 43 Cleaning position 44 Tool control position 45 Tool control device 46 Provisioning axis A support axis B Rotary table axis b Width of the tool magazine C machining axis D axis of rotation L Longitudinal axis of the tool magazine h Height of the tool magazine x Horizontal axis perpendicular to the machining axis y vertical axis z Horizontal axis parallel to the machining axis α predetermined, (acute) angle between the gripper arms γ predetermined angle between the tool magazine and the work spindle QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2005 003 220 B4

[0003] US 2024 / 0058880 A1

[0004]

Claims

[1] Machine tool (10) for machining workpieces, comprising: - at least one work spindle (11) with a tool holding device (15) which is connected to a rotary drive device (16) and is set up for the rotary drive of the work spindle (11); - Workpiece table (12) with a support (20) on which at least one workpiece () and / or a workpiece pallet (23) with at least one workpiece () arranged on it can be clamped, and at least one bearing block (21) to which a interference contour (38) is assigned; - a tool magazine (13) which is configured to hold a plurality of tools (27) and to provide one of the tools (27) as a tool to be used (27a) at a provisioning position (33) and in a provisioning orientation, - a tool-changing gripper (14) having two gripper arms (29, 30) rotatable about a common axis of rotation (D), each of which has a gripper coupling (34, 35) for receiving a tool (27), wherein the gripper arms (29, 30) are arranged at a predetermined angle (α) to each other, the apex of which lies on the axis of rotation (D) and which is less than 90°; and - a control device (31) configured to control the tool change gripper (14) in such a way that a tool (27b) picked up by the tool holding device (15) of the work spindle (11) and brought into a change position (32) is replaced by a new tool (27a) provided in the staging position (28), wherein at least the gripper couplings (34, 35) occupied by a tool (27, 27a, 27b) are always outside an area which is a projection of the interference contour (38) onto the plane of motion of the gripper arms (29, 30). [2] Machine tool (10) according to claim 1, characterized by , that a range of motion for the gripper arms (29, 30) is defined as follows: - that the gripper couplings (34, 35) are movable on a circle around the axis of rotation (D) when both gripper arms (29, 30) are unoccupied; - that the gripper couplings (34, 35) are movable on a partial arc of the circle around the axis of rotation (D) when at least one of the two gripper couplings (34, 35) is fitted with a tool (27). [3] Machine tool (10) according to claim 2, characterized by , that the limits of the movement range are chosen such that the occupied gripper couplings (34, 35) lie outside the projection of the disturbance contour (38) onto the circular plane in which the gripper arms (29, 30) move. [4] Machine tool (10) according to any of the preceding claims, characterized by, that the predetermined angle (α) lies between 20° and 80°, preferably between 30° and 70°, particularly preferably between 40° and 60°. [5] Machine tool (10) according to any of the preceding claims, characterized by , that the gripper couplings (34, 35) have receiving openings (36) which are each oriented in the circumferential direction, wherein the receiving openings (36) of the gripper couplings (34, 35) are arranged such that both are located on opposite sides of the gripper arms (29, 30) or one of the two is located on a side facing the other gripper arm (29, 30). [6] Machine tool according to one of the preceding claims, characterized in that it has a tool handling room (39) in which the tools (27) are provided from the tool magazine (13) and dispensed to the tool magazine (13), and a working room (40) separate from the tool handling room (39) in which the workpiece is machined by means of the tool (27) received by the working spindle (11). [7] Machine tool according to claim 6, characterized in that it has the following: - an opening and closing partition door (41) that separates the tool handling area (39) from the work area (40) when closed; - a cleaning device arranged in the tool handling area (39) and designed for cleaning tools (27); and / or - a tool control device arranged in the tool handling room (39) and equipped for the control of tools (27). [8] Machine tool according to claim 7, characterized in that the tool change gripper (14) is configured to perform preparatory and / or post-processing operations, such as providing, cleaning and / or checking tools, in the tool handling room (39) with the separating door (41) closed. [9] Machine tool according to one of the preceding claims, characterized in that the provision position (33) and the changeover position (32) are arranged on a circle around the axis of rotation (D), preferably diametrically opposite each other, wherein on the circle around the axis of rotation (D) between the two positions a cleaning position (43) in which a tool is cleaned by means of the cleaning device and / or a tool control position (44) in which a tool is checked by means of the tool control device (45) are arranged. [10] Machine tool according to claim 9, characterized in that a first angle between the provision position (33) and the tool control position (45) is approximately 90°. [11] Machine tool (10), in particular according to one of the preceding claims, characterized by, that the tool magazine (13) has a staging device (28) which is configured to bring a new tool (27a) from the tool magazine (13) into the staging position (33) and the staging orientation (33). [12] Machine tool according to any one of the preceding claims, characterized by , that the tool magazine (13) is dimensioned such that the ratio between the height (h) of the tool magazine (13) and the width (b) of the tool magazine (13) is greater than or equal to 1, preferably the ratio is greater than 2 or 3. [13] Machine tool according to any one of the preceding claims, characterized by , that the tools (27b) received by the tool magazine (13) are aligned in a storage orientation. [14] Tool change method in a machine tool (10) according to one of the preceding claims, comprising the following steps: - Deploying a new tool (27a) in the deployment position (33); - first rotation of the gripper arms () around the axis of rotation (D) such that the first gripper coupling (34) is brought into the provision position and picking up the provided, new tool (27a) with the first gripper coupling (34); - Providing the previously used tool (27a) by means of the work spindle (11) in the changeover position; - second rotation of the gripper arms (29, 30) around the axis of rotation (D) such that the second gripper coupling (35) is brought into the change position (32) and pick up the previously used tool (27b) with the second gripper coupling (35); - third rotation of the gripper arms (29, 30) around the axis of rotation such that the first gripper coupling (34) is brought into the change position (32) and pick up the new tool (27a) with the work spindle (11); - Movement of the work spindle (11) with the newly installed tool (27a) from the changeover position (32); and - fourth rotation of the gripper arms (29, 30) around the axis of rotation such that the second gripper coupling (35) is brought into the provision position (33). [15] Tool change method according to claim 14, characterized by , that the first gripper coupling (34) is moved into the cleaning position (43) between the first rotation and the second rotation about the axis of rotation (D), whereby the new tool (27a) is cleaned by means of the cleaning device. [16] Tool change method according to claim 14 or 15, characterized by , that the second gripper coupling (35) is moved into the tool control position between the third rotation and the fourth rotation about the axis of rotation (D), whereby the tool already in use (27b) is checked by means of the tool control device (45).

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