Turret controller 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 technology]

[0002] Some machine tools, such as automatic lathes, are equipped with a turret tool rest. The turret of the turret tool rest is formed in a rectangular column shape, and tool holders, on which tools such as drills and reamers are attached, are attached to each of the turret faces, which are the multiple peripheral surfaces of the column.

[0003] A tool holder selected according to the type of machining of the workpiece to be processed is attached to each turret face, but in order to machine the workpiece in sequence using the tool holders respectively attached to the different turret faces, it is necessary to rotate the turret and switch the tool holder to perform an indexing operation each time the machining process progresses.

[0004] Here, in order to shorten the time required to switch between tool holders, a layout may be adopted in which multiple tool holders used in machining are arranged on turret faces adjacent to each other in the rotation direction.

[0005] In particular, when the number of tool holders attached to the turret is small, the tool holders are concentrated in a specific angle range of the turret, causing the weight balance around the center of rotation to become unbalanced, and when the turret is rotated and an indexing operation is performed on a specific tool holder, an overshoot occurs in which the turret passes the intended stopping position, making it impossible to accurately control the stopping position.Furthermore, after this overshoot, an overshoot also occurs in the operation to return to the correct stopping position, resulting in a hunting operation.

[0006] Furthermore, even a slight deviation in the stopping position causes a phase shift in the meshing when the curvic coupling engages with the turret as the turret rotates, resulting in a deviation in the stopping position.

[0007] In view of this, a turret rotation speed determination device has been proposed that further increases the speed at which the turret rotates while ensuring the accuracy of the stopping position (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2000-218470 A Summary of the Invention [Problem to be solved by the invention]

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

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

[0011] A first aspect of the present invention is a turret control device comprising: a drive unit that rotates about a predetermined center of rotation, and that has a plurality of turret faces on which tool holders including tools are attached, and that rotates the turret about the center of rotation; a control unit that controls the operation of the drive unit; a reception unit that receives input of information related to a tool layout that specifies the arrangement state of the tool holders attached to the turret faces; a center of gravity position calculation unit that calculates the position of the center of gravity of the turret in the tool layout based on the information related to the tool layout input to the reception unit, information related to the weight and center of gravity of the tool holders attached to the turret faces, and information related to the weight and center of gravity of the turret alone; and an eccentricity amount calculation unit that calculates an amount of eccentricity of the position of the center of gravity of the turret calculated by the center of gravity position calculation unit relative to the position of the center of rotation, and the control unit controls the rotation speed of the turret by the drive unit based on the amount of eccentricity.

[0012] A second aspect of the present invention is a turret lathe comprising a turret device including a turret that rotates around a predetermined center of rotation and has a plurality of turret faces to which a tool holder including a tool is attached, a main spindle that holds a workpiece to be machined by the tool attached to the turret, and a control device that controls the main spindle and the turret, the control device having the turret control device according to the present invention. Effect of the Invention

[0013] The turret control device and turret lathe according to the present invention can improve the accuracy of the stopping position after the turret rotates. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a perspective view showing a schematic view of the main external appearance of a turret lathe. [Diagram 2] 2 is a front view showing a schematic view of the turret when viewed in the direction of the turret axis C2. FIG. [Diagram 3] 2 is a block diagram showing the configuration of a control device 30 for controlling the operation of a turret lathe. FIG. [Figure 4] FIG. 13 is a diagram showing the position m1 of the center of gravity of the tool holder T1 alone in the local coordinate system. [Diagram 5] FIG. 13 is a diagram showing the center of gravity m4 of the tool holder T4 alone in the local coordinate system. [Figure 6] 1A and 1B are schematic diagrams showing the position of the center of gravity M' (X', Y') of the turret in the global coordinate system and the amount of eccentricity δ from the center of rotation (axis C2) according to an example of the layout of the tool holders, respectively, and show a layout in which the tool holders are concentrated and arranged in an angular range θ1. [Figure 7] 1A and 1B are schematic diagrams showing the position of the center of gravity M' (X', Y') of the turret in the global coordinate system and the amount of eccentricity δ from the center of rotation (axis C2) according to an example of the layout of the tool holders, respectively, in which the tool holders are distributed and arranged in an angular range θ2 (>θ1). [Figure 8] 4 is a flowchart showing a detailed operation of the control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0016] Fig. 1 is a perspective view showing a schematic appearance of the main part of the turret lathe 100, Fig. 2 is a front view showing a schematic appearance of the turret 22 as viewed in the direction of the axis C2 of the turret 22, and Fig. 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 turret device 20 shown in Fig. 1, and the control device 30 shown in Fig. 3. In addition to the spindle 10, turret device 20, and control device 30, the turret lathe 100 also includes a cutting fluid device that sprays cutting fluid onto a workpiece W, which is an object to be machined, when cutting the workpiece W, and other components, but a description of these components will be omitted. The turret lathe 100 may further include a second spindle (back 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 this holding mechanism holds a workpiece W, which is mainly a bar material. The spindle 10 is rotatable around 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. The spindle 10 is also capable of moving 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, for example. The shape of the turret 22 is not limited to a regular dodecagonal prism, and may be a regular decagonal prism, or may be another regular polygonal prism such as a regular octagonal prism. The shape of the turret 22 is not limited to a regular polygonal prism having a regular polygonal cross section, and may be a polygonal prism having a non-regular polygonal cross section. In other words, the turret 22 may have any shape as long as a plurality of turret surfaces 23, which are peripheral surfaces around an axis C2, which 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 an axis C2, which is the central axis of a regular dodecagonal prism. The turret 22 has a peripheral surface around the axis C2 formed of planes parallel to the axis C2. Each of these planes is a turret surface 23 to which a tool holder T, which will be described later, is attached. The turret 22 of this embodiment has 12 turret surfaces 23, and when each turret surface 23 is to be described separately, they are called turret surfaces 23a, 23b, 23c, 23d, 23e, 23f, 23g, 23h, 23j, 23k, 23m, and 23n, as shown in FIG. 2 (the reference numerals 23i (lowercase English i) and 23l (lowercase English el) are excluded to prevent misidentification with other characters).

[0021] 1 and 2, a tool holder T can be attached to each turret surface 23. When the turret 22 rotates about the axis C2, the tool holder T attached to each turret surface 23 turns about the axis C2.

[0022] The tool holder T holds a tool t for machining a workpiece W held by the spindle 10, and fixes the tool t to a turret face 23. Depending on the type of tool t held, the tool holder T can transmit a driving force supplied from the main body 21 through the turret 22 to the tool t to rotate the tool t.

[0023] The main body 21 supports the turret 22 rotatably around the axis C2 of the turret 22. The main body 21 also includes a drive unit 25. The drive unit 25 rotates the turret 22 around the axis C2, rotates a tool t of a tool holder T fixed to the turret surface 23 around the axis of the tool holder T, and turns 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, such as the opening and closing operation of the holding mechanism of the spindle 10, the rotation operation of the workpiece held by the spindle 10 about the axis C1, and the movement operation 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 a cutting fluid device.

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

[0026] In addition to the components related to controlling the operation of the turret device 20 shown in Figure 3, the control device 30 also includes a memory unit that stores a program that specifies 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, a display unit (monitor), etc., but descriptions of the components other than those related to controlling the operation of the turret device 20 will be omitted.

[0027] 3, the control device 30 includes a receiving unit 31, a center of gravity position calculation unit 32, an eccentricity amount calculation unit 33, and a control unit 34 as components related to control of the operation of the turret device 20. As far as the control device 30 is concerned, it is one embodiment of a turret control device according to the present invention.

[0028] The receiving unit 31 receives input of information (tool layout information) relating to the tool layout that specifies the arrangement state in which the tool holders T are attached on the turret faces 23, i.e., which tool holders T are attached to which of the 12 turret faces 23 of the turret 22.

[0029] In other words, the turret lathe 100 does not always have tool holders T attached to all twelve turret faces 23 (23a, ..., 23n) regardless of the content of the machining on the workpiece W, but rather, depending on the content of the machining on the workpiece W, tool holders T containing tools t of a type selected depending on the content of the machining are attached only to turret faces 23 at one or more selected positions among the twelve turret faces 23.

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

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

[0032] In this case, the user inputs to the reception unit 31 the combination of turret surface 23a (information identifying turret surface 23; the same applies below) and tool holder T1 (information identifying tool holder T; the same applies below), 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 information that specifies a combination of the information specifying the turret faces 23 and the information specifying the tool holder T for all the turret faces 23 to which the tool holder T is attached is tool layout information that specifies the arrangement state (tool layout) of the turret faces 23 to which the tool holder T is attached in the turret 22. Therefore, the receiving unit 31 receives an input of the tool layout information.

[0034] The center of gravity position calculation unit 32 calculates the center of gravity position of the turret 22 in a plane perpendicular to the axis C2 in a state in which the tool holder T is attached to the turret surface 23. Specifically, the center of gravity position calculation unit 32 stores the weight of the tool holder T alone and the center of gravity position m of the tool holder T alone in a local coordinate system (xy coordinate system) prepared for attachment to the turret surface 23, and the weight of the turret 22 alone and the center of gravity position M0 of the tool holder T alone in a global coordinate system (xy coordinate system) in a state in which no tool holder T is attached to the turret surface 23.

[0035] Fig. 4 is a diagram showing the position m1 of the center of gravity of the tool holder T1 alone in the local coordinate system, and Fig. 5 is a diagram showing the position m4 of the center of gravity of the tool holder T4 alone in the local coordinate system. For example, the tool holder T1 having a tool t1 has a predetermined weight by itself, and as shown in Fig. 4, assuming that the tool holder T1 is attached to the turret face 23, the position of the center of gravity of the tool holder T1 alone is specified as m1(x1, y1) in a local coordinate system (xy coordinate system) in which the turret face 23 is the y-axis and the center line of the tool holder T1 is the x-axis. In this way, the weight of the tool holder T1 alone and the position m1 of the center of gravity of the tool holder T1 alone that have been obtained in advance are stored in the center of gravity position calculation unit 32.

[0036] Similarly, the tool holder T4 having the tool t4 has a predetermined weight by itself, and as shown in Fig. 5, the position of the center of gravity of the tool holder T4 alone is specified as m4(x4, y4) in a local coordinate system (xy coordinate system) in which the turret surface 23 is the y-axis and the center line of the tool holder T4 is the x-axis when it is assumed that the tool holder T4 is attached to the turret surface 23. In this way, the weight of the tool holder T4 alone and the position of the center of gravity m1 of the tool holder T4 alone that have been obtained in advance are stored in the center of gravity position calculation unit 32.

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

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

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

[0040] In this case, when the tool holder T1 having a center of gravity position m1(x1, y1) in the local coordinate system is attached to the turret surface 23a parallel to the Y-axis in the global coordinate system as shown in Fig. 6, when the origin in the local coordinate system is set to the center position of the turret surface 23a in the global coordinate system, the center of gravity position M1'(X1', Y1') of the tool holder T1 alone in the global coordinate system can be calculated by adding the distance r from the axis C2 to the turret surface 23a to the x-coordinate value of the center of gravity position m1(x1, y1) in the local coordinate system (see Fig. 4). In other words, the center of gravity position M1'(X1', Y1') is the center of gravity position M1'(x1+r, y1).

[0041] In addition, in a state where the tool holder T4 having a center of gravity position m4(x4, y4) in the local coordinate system is attached to the turret face 23d parallel to the X-axis in the global coordinate system as shown in Fig. 6, when the origin in the local coordinate system is set to the center position of the turret face 23d in the global coordinate system, the center of gravity position M4'(X4', Y4') of the tool holder T4 alone in the global coordinate system can be calculated by adding the distance r from the axis C2 to the turret face 23a to the y coordinate value of the center of gravity position m4(x4, y4) in the local coordinate system (see Fig. 5). In other words, the center of gravity position M4'(X4', Y4') is the center of gravity position M4'(x4, y1+r).

[0042] For the other turret faces 23b, 23c that are not parallel to either the X-axis or the Y-axis, the origin in the local coordinate system is set to the center position of each turret face 23b, 23c in the global coordinate system, and the center of gravity positions M2' (X2', Y2'), M3' (X3', Y3') of the tool holders T2, T3 alone in the global coordinate system can be calculated according to the inclination of each turret face 23b, 23c.

[0043] The position M' of the center of gravity of the turret 22 in the global coordinate system when one or more tool holders T are attached can be calculated by applying a method for calculating the position of the center of gravity of a combination of multiple parts, which is a general formula in physics, based on the position of the center of gravity and weight of each tool holder T alone in the global coordinate system and the position of the center of gravity and weight of the turret 22 alone in the global coordinate system.

[0044] The eccentricity calculation unit 33 calculates the amount of eccentricity δ of the center of gravity M' in the global coordinate system of the turret 22 attached in the arrangement of the tool layout information, calculated by the center of gravity position calculation unit 32, relative to the axis C2 which is the rotation center of the turret 22. The position of the axis C2 in the global coordinate system is the position of the origin (0,0), and is stored in advance in the eccentricity calculation unit 33.

[0045] Here, for example, when comparing the layout shown in Fig. 6 with the layout shown in Fig. 7, the tool holders T attached to the turret 22 are arranged in an angular range θ about the axis C2 of the turret 22, and are concentrated in an angular range θ1 in the layout of Fig. 6, whereas they are dispersed over a wide angular range θ2 (>θ1) in the layout of Fig. 7. Moreover, the number of tool holders T attached in the layout of Fig. 7 is smaller than that in the layout of Fig. 6.

[0046] Therefore, the center of gravity M' in the layout of Fig. 6 has a larger eccentricity δ with respect to the axis C2, which is the center of rotation, than the center of gravity M' in the layout of Fig. 7. In a layout with a larger eccentricity δ, the weight balance becomes unbalanced when the turret 22 rotates around the axis C2, 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 in the tool holder T at a position where the workpiece W is machined (for example, a position facing the axis C1 of the spindle in Fig. 2). In the case of a layout with a large moment of inertia, however, the tool holder T may not stop at the intended stopping position and may stop past the intended stopping position, resulting in overshooting.

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

[0048] The threshold value δ0 to be compared with the eccentricity δ is a value that corresponds to the amount of eccentricity that generates an overshoot in which the tool holder T does not stop at the targeted stopping position but passes over it during an indexing operation in which the turret 22 is rotated at the rated maximum speed corresponding to each tool layout and the tool t provided in the tool holder T is stopped at a position where the workpiece W is machined (for example, a position facing the axis C1 of the spindle in FIG. 2), by calculating the eccentricity δ in advance for each of a large number of various tool layouts of one or more tool holders T illustrated in FIGS. 6 and 7.

[0049] In other words, the threshold value δ0 is set as a value that is the boundary between the amount of eccentricity when overshoot occurs and the amount of eccentricity when overshoot does not occur, by conducting experiments in which the tool holder T is rotated at the rated maximum speed and stopped by the indexing operation for many different tool layouts.

[0050] In other words, when the eccentricity δ is greater than the threshold value δ0, the control unit 34 controls the drive unit 25 so that the rotational speed of the turret 22 during the indexing operation is slower than the preset rated maximum speed and at which no overshoot occurs.

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

[0052] 8 is a flowchart showing the detailed operation of the control device 30. The more detailed operation of the control device 30 will be described below with reference to FIG.

[0053] When the indexing operation process of the turret device 20 is started, first, the reception unit 31 waits for the user to input information for identifying the tool holders T (tool holder numbers such as T1, T2, ..., etc.) and information for identifying the turret faces 23 to which the tool holders T are attached (turret face numbers such as 23a, 23b, ..., etc.) (S1). When this input is made, the arrangement of the tool holders T in the turret 22 (tool layout information) is specified, and the specified 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' in the global coordinate system of the turret 22 in a state in which the tool holder T is attached in the arrangement of the tool layout information, based on the input tool layout information, and information on the weight and center of gravity position in the local coordinate system of each tool holder T attached to the turret surface 23 in the tool layout information and stored in the center of gravity position calculation unit 32, and information on the weight and center of gravity position in the global coordinate system of the turret 22 alone (S2). The calculated center of gravity position M' is input to the eccentricity calculation unit 33.

[0055] The eccentricity calculation unit 33 calculates the amount of eccentricity δ of the center of gravity M' relative to the axis C2 based on the input center of gravity M' in the global coordinate system and the position of the axis C2 in the global coordinate system that is stored in advance by the eccentricity calculation unit 33 (S3). The amount of eccentricity δ is input to the control unit 34.

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

[0057] The control unit 34 or the driving unit 25 detects the amount of overshoot from the position where the tool holder T, which is positioned at the position where the rotation angle around the axis C2 is the largest, is indexed to the workpiece W, which is positioned on the axis C1, during the indexing operation of this trial run (S6). The amount of overshoot is set to 0 when the tool holder T stops without overshooting, and when the tool holder T overshoots and stops, the amount of overshoot is set to the rotation angle from the original stopping position.

[0058] In addition, 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 feedback controlling the rotation angle with the servo motor, and the encoder can 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 is provided with an overshoot amount detection means for detecting the rotation angle of the turret 22, and the amount of overshoot can be detected by the overshoot amount detection means.

[0060] The control unit 34 determines whether the detected amount of overshoot is greater than a pre-stored threshold (S7). The threshold, which is compared with the detected amount of overshoot, is, for example, 0. In other words, when the threshold is 0, the control unit 34 determines whether an overshoot occurs (S7).

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

[0062] On the other hand, when the control unit 34 determines that an overshoot has occurred (exceeded threshold value 0) (YES in S7), it controls the drive unit 25 to make the rotational speed of the turret 22 slower than the rated maximum speed at which it is assumed that no overshoot will occur, and performs the actual indexing operation (S13), thereby terminating the indexing operation.

[0063] The rotation speed 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) is a rotation speed that has been preset through experiments. This rotation speed that has been preset through experiments may be one rotation speed or may be a plurality of rotation speeds that are different from each other.

[0064] When multiple predetermined rotation speeds are set, the control unit 34 can select from the multiple preset rotation speeds depending on the amount of overshoot detected in step 6 (S6). In this case, multiple thresholds to be compared in step 7 (S7) are set, the control unit 34 compares the amount of overshoot with each threshold, and the control unit 34 can select one rotation speed from the multiple rotation speeds depending on whether the amount of overshoot is larger than each threshold. Specifically, the control unit 34 can select a slower rotation speed the larger the amount of overshoot detected in step 6 is.

[0065] The threshold value to be compared with the detected amount of overshoot in step 7 (S7) does not have to be 0, but may be a positive value exceeding 0. Furthermore, a plurality of threshold values ​​may be set in step 13 (S13) described above so as to correspond to a plurality of rotation speeds that are set in advance through experiments, and in step 13 (S13), the control unit 34 may set the rotation speed in stages corresponding to the ranges of the plurality of threshold values.

[0066] In step 4 (S4), when the control unit 34 determines that the eccentricity δ exceeds the threshold value δ0 (YES in S4), it displays a message on the display unit of the control device 30 to prompt the user to reconsider the tool layout (S9). In other words, when the eccentricity δ exceeds the threshold value δ0, there is a high possibility that an overshoot will occur during indexing operation in which the turret 22 is rotated at the rated maximum speed. Therefore, the control unit 34 notifies the user by displaying on the display unit that the tool layout should be changed so that an overshoot will not occur. In this case, the display unit functions as a notification unit.

[0067] On the other hand, if the user wishes to change the tool layout (YES in S10), the process 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, when tool holders T are attached to all turret faces 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 in accordance with the eccentricity amount δ detected in step 3 (S3) (S11).

[0069] In this trial run indexing operation, the tool holder T, which is positioned at the position where the rotation angle around the axis C2 is the largest from the position of the workpiece W (the position of the axis C1 in Figures 2, 6 and 7), is rotated and stopped so as to index the workpiece W placed on the axis C1.

[0070] The control unit 34 or the driving unit 25 detects the amount of overshoot from the position where the tool holder T, which is positioned at the position where the rotation angle around the axis C2 is the largest, is indexed to the workpiece W, which is positioned on the axis C1, during the indexing operation of this trial run (S12). The amount of overshoot is set to 0 when the tool holder T stops without overshooting, and when the tool holder T overshoots, the amount of overshoot is set to the rotation angle from the original stopping position when the tool holder T overshoots and stops.

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

[0072] The rotation speed 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) is a rotation speed that has been preset through experiments. This rotation speed that has been preset through experiments may be one rotation speed or may be a plurality of rotation speeds that are different from each other.

[0073] When multiple predetermined rotation speeds are set, the control unit 34 can select from the multiple preset rotation speeds depending on the amount of overshoot detected in step 6 (S6). In this case, the control unit 34 selects a slower rotation speed as the amount of overshoot detected in step 6 is larger.

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

[0075] In the control device 30 for the turret 22 and the turret lathe 100 of this embodiment, the control unit 34 slows down the rotational speed of the turret 22 in accordance with the amount of overshoot so as to reduce the amount of overshoot (processing of S13 in Figure 8), but the turret control device and turret lathe of the present invention do not need to go as far as to perform the process (S13) of the control unit 34 slowing down the rotational speed of the turret 22 in accordance with the amount of overshoot so as to reduce the amount of overshoot.

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

[0077] Furthermore, in the control device 30 for the turret 22 and the turret lathe 100 of this embodiment, the receiving unit 31 receives, manually by the user, input of information specifying the tool holder T and information specifying the turret surface 23 to which the tool holder T is attached. 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, manually by the user, input of information specifying the tool holder T and information specifying the turret surface 23 to which the tool holder T is attached.

[0078] In other words, a turret control device and a turret lathe configured such that each tool holder T is provided with a memory 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 the information identifying the tool holder T from the memory means of the tool holder T attached to that turret surface 23 can also be an embodiment of the turret control device and turret lathe of the present invention.

[0079] In the turret control device and turret lathe of such an embodiment, the reception unit 31 identifies the reading means provided on each turret surface 23 and obtains information specifying 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, thereby eliminating the need for the user to manually enter information. [Explanation of symbols]

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

Claims

1. a drive unit that rotates a turret, which rotates about a predetermined center of rotation and has a plurality of turret faces to which a tool holder including a tool is attached, around the center of rotation; A control unit that controls the operation of the drive unit; a receiving unit that receives input of information regarding a tool layout that specifies an arrangement state in which the tool holders are attached on the turret surface; and a center of gravity position calculation unit that calculates a center of gravity position of the turret in the tool layout based on information about the tool layout inputted to the reception unit, information about a weight and a center of gravity position of the tool holder attached to the turret surface, and information about a weight and a center of gravity position of the turret alone; an eccentricity amount calculation unit that calculates an eccentricity amount 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 rotation speed of the turret by the drive unit based on the amount of eccentricity.

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

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

4. a turret device including a turret that rotates about a predetermined center of rotation and has a plurality of turret faces to which a tool holder including a tool is attached; a spindle for holding a workpiece to be machined by the tool attached to the turret; a control device for controlling the spindle and the turret, A turret lathe, comprising the control device according to any one of claims 1 to 3.

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