Turret control device and turret lathe

Abstract

To improve the precision of a stop position after the turret has rotated in a turret controller.SOLUTION: A turret lathe 100 comprises: a drive part 25, which rotates a turret 22, keeping a tool holder T including a tool t mounted to have 12 turret faces 23, on an axis C2; a control part 34, which controls the operation of the drive part 25; a reception part 31, which receives an input of information on a tool layout specifying an arrangement state that the tool holder T is mounted; a gravity center position calculation part 32, which calculates a gravity center position M' of the turret 22 on the layout on the basis of information on the inputted tool layout, information on the gravity and the gravity center position of the mounted tool holder T, and information on the gravity and the gravity center position in a single body of the turret 22; and an eccentricity calculation part 33, which calculates the eccentricity δ of the gravity center position M' to the axis C2, the control part 34 controlling the rotation speed of the turret 22 on the basis of the eccentricity δ.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a turret control device and a turret lathe.

Background Art

[0002] Some machine tools such as automatic lathes have a turret tool post. The turret of the turret tool post is formed in a prismatic shape, and tool holders on which tools such as drills and reamers are mounted are attached to turret surfaces that are a plurality of peripheral surfaces of the prism.

[0003] Tool holders selected according to the processing type of the workpiece to be processed are attached to each turret surface. However, in order to perform processing in order by the tool holders attached to different turret surfaces for the workpiece, as the processing process progresses, it is necessary to rotate the turret to switch the tool holders and perform an indexing operation.

[0004] Here, in order to shorten the switching time of the tool holders, a layout may be adopted in which a plurality of tool holders used for processing are arranged on adjacent turret surfaces in the rotational direction.

[0005] Particularly, when the number of tool holders attached to the turret is small, the tool holders are concentrated in a specific angular range of the turret, so the weight balance around the rotation center is biased. When the turret is rotated and an indexing operation is performed with a specific tool holder, an overshoot may occur where the turret passes beyond the intended stop position, and it may not be possible to accurately control the stop position. Also, an overshoot may occur even in the operation of returning to the correct stop position after this overshoot, resulting in a hunting operation.

[0006] [[ID=۲۷]] Also, a slight deviation in the stop position causes a phase deviation in the meshing when the curvic coupling when rotating the turret engages, resulting in a deviation in the stop position.

[0007] Therefore, a turret rotation speed determination device has been proposed that increases the rotation speed of the turret while ensuring accuracy of the stopping position (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2000-218470 [Overview of the project] [Problems that the invention aims to solve]

[0009] However, the turret rotation speed determination device described in Patent Document 1 above determines the turret rotation speed based on the tool layout, or based on the tool layout and the weight of the tool, but there is no specific disclosure regarding the tool layout, and the process for determining the turret rotation speed remains unclear.

[0010] The present invention has been made in view of the above circumstances, and aims to provide a turret control device and a turret lathe that can improve the accuracy of the stopping position after rotation of the turret. [Means for solving the problem]

[0011] The first aspect of the present invention is a turret control device comprising: a drive unit for rotating a turret having a plurality of turret surfaces to which tool holders including tools are attached, which rotates around a predetermined center of rotation; a control unit for controlling the operation of the drive unit; a reception unit for receiving input of information regarding a tool layout that specifies the arrangement of the tool holders attached to the turret surfaces; a center of gravity position calculation unit for calculating the center of gravity position of the turret in the tool layout based on the information regarding the tool layout input to the reception unit, information regarding the weight and center of gravity position of the tool holders attached to the turret surfaces, and information regarding the weight and center of gravity position of the turret alone; and an eccentricity calculation unit for calculating the eccentricity of the center of gravity position of the turret calculated by the center of gravity position calculation unit with respect to the position of the center of rotation, wherein the control unit controls the rotation speed of the turret by the drive unit based on the eccentricity.

[0012] Furthermore, the second aspect of the present invention is a turret lathe comprising: a turret device including a turret that rotates around a predetermined rotation center and has a plurality of turret surfaces to which tool holders including tools are attached; a spindle that holds a workpiece to be machined by the tools attached to the turret; and a control device that controls the spindle and the turret, wherein the control device is a turret control device according to the present invention. [Effects of the Invention]

[0013] The turret control device and turret lathe according to the present invention can improve the accuracy of the stopping position of the turret after rotation. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic perspective view showing the main external appearance of a turret lathe. [Figure 2] This is a schematic front view showing the turret as seen from the direction of its axis C2. [Figure 3] This is a block diagram showing the configuration of the control device 30 that controls the operation of a turret lathe. [Figure 4] This figure shows the centroid position m1 of the tool holder T1 in its local coordinate system. [Figure 5] This figure shows the centroid position m4 of the tool holder T4 in the local coordinate system. [Figure 6] These are schematic diagrams showing the centroid position M′(X′, Y′) of the turret in the global coordinate system and the eccentricity δ from the rotation center (axis C2) according to the layout of an example tool holder, and show a layout in which the tool holders are concentrated within the angular range θ1. [Figure 7] These are schematic diagrams showing the centroid position M′(X′, Y′) of the turret in the global coordinate system and the eccentricity δ from the rotation center (axis C2) according to the layout of an example tool holder, and show a layout in which the tool holders are distributed within the angular range θ2 (>θ1). [Figure 8] This is a flowchart detailing the operation of the control device. [Modes for carrying out the invention]

[0015] Embodiments of the turret control device and turret lathe according to the present invention will be described below with reference to the drawings.

[0016] Figure 1 is a schematic perspective view showing the main external appearance of the turret lathe 100, Figure 2 is a schematic front view showing the turret 22 as viewed in the direction of the turret 22 axis C2, and Figure 3 is a block diagram showing the configuration of the control device 30 that controls the operation of the turret lathe 100. The turret lathe 100 is one embodiment of the turret lathe according to the present invention.

[0017] The turret lathe 100 includes the spindle 10 and the turret device 20 shown in FIG. 1, and the control device 30 shown in FIG. 3. In addition to the spindle 10, the turret device 20, and the control device 30, the turret lathe 100 includes a coolant device that sprays coolant for cutting the workpiece W to be machined onto the workpiece, but the description thereof is omitted. Further, the turret lathe 100 may further include a second spindle (rear spindle), a second turret device, and the like.

[0018] The spindle 10 is provided with a holding mechanism such as a collet chuck at its tip, and the workpiece W, which is mainly a bar material, is held by this holding mechanism. The spindle 10 is rotatable about an axis C1 parallel to the z-axis direction, which is the longitudinal direction of the spindle 10, under the control of the control device 30. Further, the spindle 10 is movable forward and backward parallel to the z-axis under the control of the control device 30.

[0019] The turret device 20 includes a main body 21 and a turret 22. The turret 22 is formed in a regular dodecagonal prism shape as an example. The shape of the turret 22 is not limited to a regular dodecagonal prism shape, and may be a regular decagonal prism shape, or another regular polygonal prism shape such as a regular octagonal prism shape. Further, the shape of the turret 22 is not limited to a regular polygonal prism shape with a regular polygon cross-section, and may be a polygonal prism shape with a polygon cross-section that is not a regular polygon. That is, the turret 22 only needs to have a shape in which a plurality of turret surfaces 23, which are circumferential surfaces around an axis C2 that is the central axis of the polygonal prism, are planes parallel to the axis C2.

[0020] The turret 22 of this embodiment is configured to be rotatable around axis C2, which is the central axis of a regular dodecagonal prism. The circumferential surfaces of the turret 22 around axis C2 are each formed by planes parallel to axis C2. Each of these planes is a turret surface 23 to which a tool holder T, described later, is attached. The turret 22 of this embodiment has 12 turret surfaces 23, and when describing each turret surface 23 separately, they are referred to as turret surfaces 23a, 23b, 23c, 23d, 23e, 23f, 23g, 23h, 23j, 23k, 23m, and 23n, as shown in Figure 2 (the symbols 23i (lowercase I) and 23l (lowercase L) have been excluded to prevent confusion with other characters).

[0021] As shown in Figures 1 and 2, a tool holder T can be attached to each turret surface 23. As the turret 22 rotates around axis C2, the tool holders T attached to each turret surface 23 also rotate around axis C2.

[0022] The tool holder T holds the tool t used to machine the workpiece W held on the spindle 10, and fixes the tool t to the turret surface 23. Depending on the type of tool t being held, the tool holder T can also transmit the driving force supplied from the main body 21 through the turret 22 to the tool t, thereby rotating the tool t.

[0023] The main body 21 supports the turret 22 so that it can rotate around the axis C2 of the turret 22. The main body 21 also includes a drive unit 25. The drive unit 25 is capable of rotating the turret 22 around the axis C2, rotating the tool t of the tool holder T fixed to the turret surface 23 around the axis of the tool holder T, or pivoting the tool holder T itself.

[0024] The control device 30 controls the overall operation of the turret lathe 100. Specifically, the control device 30 controls the operation of the spindle 10, including the opening and closing of the spindle 10's holding mechanism, the rotation of the workpiece held by the spindle 10 around axis C1, and the movement of the spindle 10 itself in the z-axis direction, as well as the operation of the turret device 20. In addition to controlling the operation of the spindle 10 and the turret device 20, the control device 30 also controls the operation of components of the turret lathe 100, such as the cutting fluid device.

[0025] The control device 30 shown in Figure 3 is a block diagram that shows only the configuration related to the control of the operation of the turret device 20, as one embodiment of the turret control device according to the present invention, among the control of the components provided in the turret lathe 100 described above.

[0026] In addition to the configuration for controlling the operation of the turret device 20 shown in Figure 3, the control device 30 also includes a storage unit that stores a program defining the operation of the entire turret lathe 100, including the spindle 10, an operation panel for inputting instructions regarding the operation of the entire turret lathe 100, and a display unit (monitor). However, a description of the configuration other than those related to controlling the operation of the turret device 20 will be omitted.

[0027] As shown in Figure 3, the control device 30 comprises a reception unit 31, a center of gravity position calculation unit 32, an eccentricity calculation unit 33, and a control unit 34, as configurations for controlling the operation of the turret device 20. The control device 30 is one embodiment of the turret control device according to the present invention as far as it relates to controlling the operation of the turret device 20.

[0028] The reception unit 31 receives input information regarding the tool layout (tool layout information) that identifies the arrangement of tool holders T on the turret surfaces 23, specifically which tool holder T is attached to which of the 12 turret surfaces 23 of the turret 22.

[0029] In other words, regardless of the type of machining performed on the workpiece W, the turret lathe 100 does not always have tool holders T attached to all 12 turret surfaces 23 (23a, ..., 23n). Instead, depending on the type of machining performed on the workpiece W, tool holders T containing a tool t of a type selected according to the type of machining are attached only to one or more selected turret surfaces 23 out of the 12 turret surfaces 23.

[0030] The reception unit 31 receives tool layout information entered by the user. The tool layout information entered by the user into the reception unit 31 is information that associates information identifying the turret surface 23 on which the tool holder T is attached (turret surface 23a, ..., 23n) out of the 12 turret surfaces 23a, ..., 23n with information identifying the tool holder T attached to that identified turret surface 23a, ..., 23n (T1, T2, T3, T4, ...). The tool layout information may also include information identifying the tool t (t1, t2, t3, t4, ...).

[0031] For example, in the state shown in Figure 2, the turret 22 has a tool holder T1 attached to the turret surface 23a, a tool holder T2 attached to the turret surface 23b, a tool holder T3 attached to the turret surface 23c, a tool holder T4 attached to the turret surface 23d, and no tool holders T attached to the other turret surfaces 23e, ..., 23n.

[0032] In this case, the user inputs the following combinations to the reception unit 31: the combination of turret surface 23a (information identifying turret surface 23; the same applies hereinafter) and tool holder T1 (information identifying tool holder T; the same applies hereinafter), the combination of turret surface 23b and tool holder T2, the combination of turret surface 23c and tool holder T3, and the combination of turret surface 23d and tool holder T4.

[0033] The combination of information identifying these turret surfaces 23 and information identifying the tool holder T, for all turret surfaces 23 to which the tool holder T is attached, constitutes tool layout information that identifies the arrangement (tool layout) of the turret surfaces 23 to which the tool holder T is attached in the turret 22. Therefore, the receiving unit 31 receives the input of tool layout information.

[0034] The center of gravity calculation unit 32 calculates the center of gravity of the turret 22 in a plane perpendicular to axis C2 when tool holders T are attached to the turret surface 23. Specifically, the center of gravity calculation unit 32 stores the individual weight and the individual center of gravity position m in its local coordinate system (xy coordinate system) for each tool holder T provided to be attached to the turret surface 23, and the individual weight and the individual center of gravity position M0 in its global coordinate system (XY coordinate system) for the turret 22 when no tool holders T are attached to the turret surface 23.

[0035] Figure 4 shows the center of gravity position m1 of tool holder T1 alone in the local coordinate system, and Figure 5 shows the center of gravity position m4 of tool holder T4 alone in the local coordinate system. For example, a tool holder T1 holding a tool t1 has a predetermined weight on its own, and assuming that the tool holder T1 is attached to the turret surface 23 as shown in Figure 4, the center of gravity position of the tool holder T1 alone in a local coordinate system (xy coordinate system) where the turret surface 23 is the y-axis and the center line of the tool holder T1 is the x-axis is specified as m1(x1,y1). Thus, the weight and center of gravity position m1 of the tool holder T1 alone, which have been determined in advance, are stored in the center of gravity position calculation unit 32.

[0036] Similarly, a tool holder T4 having a tool t4 has a predetermined weight on its own. Assuming that the tool holder T4 is mounted on the turret surface 23 as shown in Figure 5, the center of gravity of the tool holder T4 on its own is determined as m4(x4,y4) in a local coordinate system (xy coordinate system) where the turret surface 23 is the y-axis and the center line of the tool holder T4 is the x-axis. Thus, the weight and center of gravity m1 of the tool holder T4 on its own, which have been determined in advance, are stored in the center of gravity calculation unit 32.

[0037] The center of gravity position calculation unit 32 also stores the weight of the turret 22, which has been determined in advance, and the position of its center of gravity M in a plane perpendicular to axis C2, where axis C2, which is the center of rotation, is the origin (0,0) of the global coordinate system (XY coordinate system).

[0038] Then, the center of gravity position calculation unit 32 calculates the center of gravity position M' of the turret 22 in the global coordinate system with the tool holder T attached, based on the tool layout information input to the reception unit 31, the weight of the tool holder T attached to the turret surface 23 in that tool layout information, and information regarding the center of gravity position in the local coordinate system, as well as the weight of the turret 22 attached to the turret surface 23 in that tool layout information and information regarding the center of gravity position in the global coordinate system, in the arrangement of the tool layout information.

[0039] Figures 6 and 7 are schematic diagrams showing the centroid position M′(X′, Y′) and eccentricity δ from the rotation center (axis C2) of the turret 22 in the global coordinate system, respectively, according to the tool layout of an example of a tool holder T. Figure 6 shows a tool layout in which the tool holders T are concentrated in the angular range θ1, and Figure 7 shows a layout in which the tool holders T are distributed in the angular range θ2 (>θ1).

[0040] Here, when a tool holder T1 having a centroid position m1(x1,y1) in the local coordinate system is mounted on a turret surface 23a parallel to the Y-axis in the global coordinate system, as shown in Figure 6, the centroid position M1′(X1′,Y1′) of the tool holder T1 alone in the global coordinate system can be calculated by adding the distance r from axis C2 to the turret surface 23a to the x-coordinate value of the centroid position m1(x1,y1) in the local coordinate system (see Figure 4). In other words, the centroid position M1′(X1′,Y1′) is the centroid position M1′(x1+r,y1).

[0041] Furthermore, when a tool holder T4 having a centroid position m4(x4,y4) in the local coordinate system is mounted on a turret surface 23d parallel to the X-axis in the global coordinate system, as shown in Figure 6, the centroid position M4'(X4',Y4') of the tool holder T4 alone in the global coordinate system can be calculated by adding the distance r from axis C2 to the turret surface 23a to the y-coordinate value of the centroid position m4(x4,y4) in the local coordinate system (see Figure 5). In other words, the centroid position M4'(X4',Y4') is the centroid position M4'(x4,y1+r).

[0042] For tool holders T2 and T3 on other turret surfaces 23b and 23c that are not parallel to the X and Y axes, the origin in the local coordinate system is set to the respective center positions of turret surfaces 23b and 23c in the global coordinate system, and the centroid positions M2'(X2', Y2') and M3'(X3', Y3') of the tool holders T2 and T3 individually in the global coordinate system can be calculated according to the inclination of each turret surface 23b and 23c.

[0043] Furthermore, the center of gravity M' of the turret 22 in the global coordinate system when one or more tool holders T are attached can be calculated by applying a common physics formula for calculating the center of gravity of a combination of multiple components, based on the center of gravity and weight of each individual tool holder T in the global coordinate system and the center of gravity and weight of the turret 22 in the global coordinate system.

[0044] The eccentricity calculation unit 33 calculates the eccentricity δ of the turret 22, which is mounted according to the tool layout information calculated by the centroid position calculation unit 32, with respect to axis C2, which is the rotation center of the turret 22, and the centroid position M' in the global coordinate system. The position of axis C2 in the global coordinate system is the position of the origin (0,0) and is stored in the eccentricity calculation unit 33 beforehand.

[0045] For example, comparing the layout shown in Figure 6 with the layout shown in Figure 7, the angular range θ around the axis C2 of the turret 22, where the tool holders T attached to the turret 22 are located, is concentrated in angular range θ1 in the layout of Figure 6, whereas in the layout of Figure 7, they are distributed over a wider angular range θ2 (>θ1). Moreover, the layout of Figure 7 has fewer attached tool holders T than the layout of Figure 6.

[0046] Therefore, the center of gravity position M' in the layout of Figure 6 has a larger eccentricity δ with respect to the position of axis C2, which is the center of rotation, than the center of gravity position M' in the layout of Figure 7. And in a layout with a large eccentricity δ, when the turret 22 rotates around axis C2, the weight balance becomes uneven, and the moment of inertia becomes large. The drive unit 25 rotates the turret 22 at the rated maximum speed and performs an indexing operation to stop the tool t provided on the tool holder T at the position for machining the workpiece W (for example, the position facing axis C1 of the main spindle in Figure 2). However, in the case of a layout with a large moment of inertia, an overshoot may occur in which the tool holder T does not stop completely at the target stopping position and stops past the target stopping position.

[0047] The control unit 34 controls the operation of the drive unit 25, which is provided on the main body 21 of the turret device 20, based on the eccentricity δ calculated by the eccentricity calculation unit 33. Specifically, when the eccentricity δ is greater than a predetermined threshold δ0, the control unit 34 controls the drive unit 25 so that the rotation speed of the turret 22 is slower than the preset rated maximum speed. The threshold δ0, which is compared with the eccentricity δ, is stored in the control unit 34.

[0048] The threshold δ0, which is compared with the eccentricity δ, is calculated in advance for each of the many different tool layouts of one or more tool holders T as exemplified in Figures 6 and 7. Corresponding to each tool layout, the turret 22 is rotated at the rated maximum speed, and during the indexing operation to stop the tool t attached to the tool holder T at the position for machining the workpiece W (for example, the position facing the spindle axis C1 in Figure 2), the threshold δ0 is the value corresponding to the amount of eccentricity at which an overshoot occurs, where the tool holder T does not stop completely at the intended stopping position but passes the intended stopping position.

[0049] In other words, the threshold δ0 is set as the boundary value between the eccentricity at which overshoot occurs and the eccentricity at which overshoot does not occur, based on experiments conducted for numerous different tool layouts of the tool holder T, where it is rotated at the rated maximum speed and stopped in indexing operation.

[0050] In other words, when the eccentricity δ is greater than the threshold δ0, the control unit 34 controls the drive unit 25 so that the rotation speed of the turret 22 in indexing operation is slower than the preset rated maximum speed and does not cause overshoot.

[0051] On the other hand, when the eccentricity δ is not greater than the threshold δ0, the control unit 34 controls the drive unit 25 so that the rotational speed of the turret 22 in indexing operation becomes the preset rated maximum speed.

[0052] Figure 8 is a flowchart detailing the operation of the control device 30. A more detailed explanation of the operation of the control device 30 is provided below with reference to Figure 8.

[0053] When the indexing operation of the turret device 20 is initiated, the reception unit 31 first waits for input from the user, including information identifying the tool holder T (tool holder numbers such as T1, T2, etc.) and information identifying the turret surface 23 to which those tool holders T are attached (turret surface numbers such as 23a, 23b, etc.) (S1). Once this input is received, the arrangement of the tool holder T on the turret 22 (tool layout information) is identified, and the identified tool layout information is input to the center of gravity position calculation unit 32.

[0054] The center of gravity position calculation unit 32 calculates the center of gravity position M' of the turret 22 in the global coordinate system with the tool holders T attached in the arrangement of the tool layout information, based on the input tool layout information and the information stored in the center of gravity position calculation unit 32 regarding the individual weight and center of gravity position of each tool holder T attached to the turret surface 23 in the tool layout information, as well as the information regarding the individual weight and center of gravity position of the turret 22 in the global coordinate system (S2). The calculated center of gravity position M' is input to the eccentricity calculation unit 33.

[0055] The eccentricity calculation unit 33 calculates the eccentricity δ of the centroid position M' with respect to axis C2 based on the input centroid position M' in the global coordinate system and the position of axis C2 in the global coordinate system, which the eccentricity calculation unit 33 has stored in advance (S3). The eccentricity δ is input to the control unit 34.

[0056] The control unit 34 compares the input eccentricity δ with a threshold δ0 that the control unit 34 has stored in advance (S4). If the control unit 34 determines that the eccentricity δ does not exceed the threshold δ0 (NO in S4), it controls the drive unit 25 to perform a trial run of indexing operation, which rotates the turret 22 at the rated maximum speed (S5). This trial run indexing operation rotates and stops the tool holder T, which is positioned at the position where the rotation angle around axis C2 is largest from the position of the workpiece W (position of axis C1 in Figures 2, 6, and 7), to index it to the workpiece W positioned on axis C1.

[0057] The control unit 34 or the drive unit 25 detects the amount of overshoot (S6) from the position where the tool holder T, positioned at the location with the largest rotation angle around axis C2, indexes to the workpiece W positioned on axis C1 during the indexing operation of this trial run. The amount of overshoot is set to 0 when the machine stops without overshooting, and if overshooting occurs, it is set to the rotation angle from the position where the machine should have stopped after the overshoot.

[0058] Furthermore, when the drive unit 25 rotates the turret under the control of a servo motor, the amount of overshoot can be detected by an encoder used when the rotation angle is feedback-controlled by the servo motor, and the encoder can be made to function as an overshoot amount detection means for detecting the amount of overshoot.

[0059] When the drive unit 25 is a drive means other than a servo motor, for example, when the drive means is a stepping motor, the turret device 20 can be provided with an overshoot amount detection means for detecting the rotation angle of the turret 22, and the overshoot amount can be detected by the overshoot amount detection means.

[0060] The control unit 34 determines whether the detected overshoot amount is greater than a pre-stored threshold (S7). The threshold amount used for comparison with the detected overshoot amount is, for example, 0. In other words, if the threshold is 0, the control unit 34 determines whether or not there is an overshoot (S7).

[0061] Then, when the control unit 34 determines that there was no overshoot (the threshold did not exceed 0) (NO in S7), it controls the drive unit 25 to set the rotation speed of the turret 22 to the rated maximum speed, performs the actual indexing operation (S8), and terminates the indexing operation.

[0062] On the other hand, when the control unit 34 determines that an overshoot has occurred (the threshold has exceeded 0) (YES in S7), it controls the drive unit 25 to set the rotation speed of the turret 22 to a speed slower than the rated maximum speed at which overshoot is not expected to occur, and performs the actual indexing operation (S13), and then terminates the indexing operation.

[0063] Furthermore, when the control unit 34 controls the drive unit 25 so that the rotation speed of the turret 22 is slower than the rated maximum speed (S13), the rotation speed is a rotation speed that has been set experimentally. This experimentally set rotation speed may be a single rotation speed or a number of different rotation speeds.

[0064] When multiple predetermined rotation speeds are set, the control unit 34 can select one of the multiple predetermined rotation speeds according to the magnitude of the overshoot detected in step 6 (S6). In this case, multiple comparison thresholds are set in step 7 (S7), and the control unit 34 compares the overshoot amount with each threshold. The control unit 34 can then select one rotation speed from the multiple rotation speeds according to the relative magnitude of the overshoot amount with each of the compared thresholds. Specifically, the control unit 34 can select a slower rotation speed the larger the overshoot amount detected in step 6.

[0065] In step 7 (S7), the threshold value used for comparison with the detected overshoot amount does not have to be zero; it does not need to be zero, but any positive value greater than zero is acceptable. Furthermore, multiple threshold values ​​may be set to correspond to multiple rotation speeds predetermined by the experiment in step 13 (S13) described above, and in step 13 (S13), the control unit 34 may set the rotation speed in steps corresponding to the range of the multiple threshold values.

[0066] In step 4 (S4), if the control unit 34 determines that the eccentricity δ exceeds the threshold δ0 (YES in S4), it displays a message on the display unit of the control device 30 prompting a reconsideration of the tool layout (S9). That is, when the eccentricity δ exceeds the threshold δ0, there is a high probability that overshoot will occur during indexing operation when the turret 22 is rotated at the rated maximum speed. Therefore, the control unit 34 displays on the display unit that the tool layout should be changed to one that does not cause overshoot, prompting the user to take action. In this case, the display unit functions as a notification unit.

[0067] In contrast, if the user changes the tool layout (YES in S10), the system returns to before step 1 (S1).

[0068] On the other hand, if the user does not change the tool layout (NO in S10), for example, if tool holders T are attached to all turret surfaces 23 and the arrangement of the tool holders T cannot be changed, the control unit 34 controls the drive unit 25 to perform a trial run of the indexing operation of the turret 22 at a rotational speed lower than the rated maximum speed, which is preset according to the eccentricity δ detected in step 3 (S3) (S11).

[0069] The indexing operation in this trial run rotates and stops the tool holder T, which is positioned at the location where the rotation angle around axis C2 is largest from the position of workpiece W (position of axis C1 in Figures 2, 6, and 7), so that it is indexed to workpiece W positioned on axis C1.

[0070] The control unit 34 or the drive unit 25 detects the amount of overshoot (S12) from the position where the tool holder T, positioned at the location with the largest rotation angle around axis C2, indexes to the workpiece W positioned on axis C1 during the indexing operation of this trial run. The amount of overshoot is set to 0 when the machine stops without overshooting, and if overshooting occurs, it is set to the rotation angle from the position where the machine should have stopped after overshooting.

[0071] The control unit 34 controls the drive unit 25 to set the rotation speed of the turret 22 to a speed slower than the rated maximum speed at which no overshoot is expected to occur, in accordance with the detected overshoot amount, and then performs the actual indexing operation (S13), and ends the indexing operation.

[0072] The rotational speed at which the control unit 34 controls the drive unit 25 to set the rotational speed of the turret 22 to a speed slower than the rated maximum speed (S13) is a rotational speed that has been set experimentally. This experimentally set rotational speed may be a single rotational speed or a number of different rotational speeds.

[0073] When multiple predetermined rotation speeds are set, the control unit 34 can select one of the multiple predetermined rotation speeds according to the magnitude of the overshoot detected in step 6 (S6). In this case, the control unit 34 selects a slower rotation speed the larger the overshoot detected in step 6.

[0074] As described in detail above, the control device 30 for the turret 22 and the turret lathe 100 of this embodiment can improve the accuracy of the stopping position of the rotation of the turret 22 by rotating the turret at a rotational speed corresponding to the tool layout of the tool holder T.

[0075] In this embodiment, the control device 30 for the turret 22 and the turret lathe 100 have a control unit 34 that slows down the rotational speed of the turret 22 in order to reduce the amount of overshoot according to the amount of overshoot (process S13 in Figure 8). However, in the turret control device and turret lathe according to the present invention, the control unit 34 does not need to perform the process of slowing down the rotational speed of the turret 22 in order to reduce the amount of overshoot according to the amount of overshoot (S13).

[0076] In other words, in the turret control device and turret lathe according to the present invention, if the eccentricity δ exceeds the threshold δ0 in the process of S4 in Figure 8 (YES in S4), the control unit 34 performs a process (S13) at that point to control the drive unit 25 so that the rotational speed of the turret 22 is at least slower than the rated maximum speed.

[0077] Furthermore, in this embodiment, the control device 30 of the turret 22 and the turret lathe 100 have a receiving unit 31 that receives information identifying the tool holder T and information identifying the turret surface 23 to which the tool holder T is attached, manually by the user. However, the turret control device and turret lathe according to the present invention are not limited to those in which the receiving unit 31 receives information identifying the tool holder T and information identifying the turret surface 23 to which the tool holder T is attached, manually by the user.

[0078] In other words, a turret control device and turret lathe can also be an embodiment of the turret control device and turret lathe according to the present invention, in which each tool holder T is provided with a storage means (such as an RFID tag) that stores information identifying the tool holder T, and each turret surface 23 is provided with an identifiable reading means (such as an RFID reader) that reads information identifying the tool holder T from the storage means of the tool holder T attached to the turret surface 23.

[0079] In the turret control device and turret lathe of this embodiment, the receiving unit 31 identifies the reading means provided on each turret surface 23 and acquires information that identifies the tool holder T read by each reading means, thereby identifying the tool holder T attached to each turret surface 23 and automatically recognizing the tool layout of the turret 22, thus eliminating the need for manual input by the user. [Explanation of symbols]

[0080] 22 Turrets 23 Turret side 25 Drive unit 30 Control device 31 Reception Department 32 Center of gravity position calculation section 33 Eccentricity calculation section 34 Control Unit 100 Turret Lathes C2 axis M′,M1′,M2′,M3′,M4′ Center of gravity position T, T1, T2, T3, T4 Tool Holders Double job t,t1,t2,t3,t4 Tool δ Eccentricity

Claims

1. A drive unit rotates a turret, which has multiple turret surfaces to which tool holders including tools are attached, around a predetermined center of rotation, A control unit that controls the operation of the drive unit, A receiving unit that receives input information regarding the tool layout, which specifies the arrangement of the tool holder on the turret surface, A center of gravity calculation unit calculates the center of gravity of the turret in the tool layout based on the information regarding the tool layout input to the reception unit, the information regarding the weight and center of gravity of the tool holder attached to the turret surface, and the information regarding the weight and center of gravity of the turret itself. The system includes an eccentricity calculation unit that calculates the eccentricity of the center of gravity position of the turret calculated by the center of gravity position calculation unit with respect to the position of the rotation center, The control unit controls the rotational speed of the turret by the drive unit based on the eccentricity, and is a turret control device.

2. The system includes a notification unit that displays information prompting a change in the tool layout, The turret control device according to claim 1, wherein the control unit controls the notification unit to notify information prompting a change in the tool layout when the eccentricity is greater than a preset threshold.

3. The system includes an overshoot detection unit that detects the amount of overshoot when an indexing operation is performed in which the turret is rotated at a predetermined rotational speed and the tool holder is stopped at the indexing position. The turret control device according to claim 1, wherein the control unit controls the drive unit to reduce the rotation speed when the overshoot amount is greater than a predetermined threshold.

4. A turret device including a turret having multiple turret surfaces that rotate around a predetermined center of rotation and to which tool holders including tools are attached, A spindle that holds the workpiece to be machined by the tool attached to the turret, The system includes a control device for controlling the spindle and the turret, The control device is a turret lathe having the turret control device described in any one of claims 1 to 3.

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