Tool exchange device

Abstract

To more accurately detect a defective attitude of a tool holder gripped by a tool magazine.SOLUTION: A tool changer 1 comprises: a tool magazine 10 that detachably grips a tool holder 30 on its outer periphery; and a laser length measuring machine 20 disposed closer to the outer peripheral side than the tool magazine 10. In the tool holder 30, a groove 40 formed in an elliptic spherical shape is provided to a part 33 facing the outer peripheral side when gripped by the tool magazine 10. The groove 40 has a depth curvature varied between the axial direction and the peripheral direction of the tool magazine 10. The laser length measuring machine 20 detects depth displacement dr of an inner surface by applying a laser beam to an inner surface of the groove 40 in the tool holder 30 gripped by the tool magazine 10. When the tool holder 30 is displaced in at least one of the axial direction and the peripheral direction with respect to the tool magazine 10, the inner surface is displaced in the depth direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tool changing device.

Background Art

[0002] The tool changing device of the machine tool disclosed in Patent Document 1 has a disk-shaped magazine body having a central axis extending in the vertical direction and rotatable around the central axis, and a plurality of chucks arranged circumferentially on the outer peripheral portion of the magazine body, and the tool holders are detachably configured. The chuck is such that the attachment / detachment direction of the tool holder is inclined by a predetermined angle with respect to the radial direction of the magazine body. According to such a configuration, it is possible to increase the outer diameter of the tool magazine without the tool magazine contacting a column or the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in order to shorten the tool change time, the tool holder may be transferred at high speed between the spindle and the tool magazine, or the tool magazine may be rotated at high speed. At this time, the tool holder may be displaced or tilted with respect to the tool magazine. Such a poor posture of the tool holder with respect to the tool magazine can cause problems such as poor attachment of the tool holder to the spindle.

[0005] Specifically, in order to produce a workpiece, it is necessary to go through many processes, and for one workpiece, it is necessary to frequently change tools. The tool change time is directly related to productivity and has a great impact on the overall production speed and the number of products produced. The tool change time may account for more than half of the total production time. Therefore, shortening the tool change time is very important from the perspective of productivity.

[0006] In order to shorten the tool change time, it is desirable to transfer the tool holder between the spindle and the tool magazine at high speed. However, the gripping part (chuck) of the tool holder in the tool magazine generally has a simple structure and cannot restrict the posture of the tool holder.

[0007] For this reason, the tool holder held by the tool magazine is likely to have a posture defect. The posture defect of the tool holder with respect to the tool magazine may cause a mounting defect (such as a core defect or inclination) of the tool holder to the spindle, and ultimately may cause a processing accuracy defect.

[0008] The present invention has been made in view of such a point, and an object thereof is to more accurately detect a posture defect of a tool holder held by a tool magazine.

Means for Solving the Problems

[0009] The tool change device according to the present invention includes a tool magazine in which a tool holder is detachably gripped on an outer peripheral portion, and an optical length measuring device disposed on an outer peripheral side of the tool magazine. The tool holder is provided with a groove portion formed in an elliptical spherical shape at a portion facing the outer peripheral side when gripped by the tool magazine. The groove portion has a curvature in the depth direction in the axial direction and the circumferential direction of the tool magazine. Radiusare different from each other, and the optical length measuring device detects the displacement in the depth direction of the inner surface by irradiating light onto the inner surface of the groove portion in the tool holder held by the tool magazine. When the tool holder is displaced with respect to the tool magazine in at least one of the axial direction and the circumferential direction, the inner surface is displaced in the depth direction.

[0010] According to such a configuration, since the groove portion is formed in an elliptical spherical shape, when the tool holder is displaced with respect to the tool magazine in at least one of the axial direction and the circumferential direction, that is, when a posture defect of the tool holder with respect to the tool magazine occurs, the inner surface of the groove portion is displaced in the radial direction of the tool magazine, that is, in the depth direction of the groove portion.

[0011] Here, the tool holder hardly displaces in the depth direction (radial direction) with respect to the tool magazine. The tool holder is usually in a thick cylindrical shape with a uniform wall thickness around the entire circumference and is located at the gripping point in the tool magazine, so thermal deformation and gripping deformation are less likely to occur. Also, the tool magazine is usually in a disc shape. For this reason, the tool holder is less likely to displace in the depth direction (radial direction) with respect to the tool magazine.

[0012] That is, the optical length measuring device detects the displacement amount including the axial displacement and the circumferential displacement of the tool holder with respect to the tool magazine by detecting the displacement in the depth direction of the inner surface of the groove portion.

[0013] Furthermore, the curvature in the depth direction of the groove portion Radius is different between the axial direction and the circumferential direction, so the magnitude of the displacement in the depth direction detected by the optical length measuring device is different between the case where the tool holder is displaced axially with respect to the tool magazine and the case where it is displaced circumferentially. Specifically, among the axial direction and the circumferential direction, when the tool holder is displaced in the direction with the larger curvature in the depth direction, the displacement in the depth direction is relatively small. On the other hand, among the axial direction and the circumferential direction, when the tool holder is displaced in the direction with the smaller curvature in the depth direction, the displacement in the depth direction is relatively large. Radius the larger Radius the smaller

[0014] In this way, based on the magnitude of the displacement in the depth direction detected by the optical length measuring instrument, it is possible to estimate whether the tool holder has displaced in the axial direction and / or the circumferential direction with respect to the tool magazine (or both).

[0015] Therefore, it is possible to more accurately detect a posture defect of the tool holder held by the tool magazine.

[0016] In one embodiment, the groove portion has a curvature in the depth direction in the circumferential direction Radius that is smaller than the curvature in the depth direction in the axial direction. Radius is smaller.

[0017] Detecting the circumferential displacement of the tool holder with respect to the tool magazine is usually more difficult than detecting the axial displacement of the tool holder with respect to the tool magazine. Specifically, when the rotation radius of the tool magazine is small, the rotation of the tool magazine is included in the circumferential displacement, making it difficult to detect the circumferential displacement. Also, when the tool holder is cylindrical, the R shape of the side surface of the tool holder is included in the circumferential displacement, making it difficult to detect the circumferential displacement.

[0018] According to such a configuration, the groove portion is formed such that the curvature in the depth direction in the circumferential direction Radius becomes small. As a result, when the tool holder is displaced in the circumferential direction with respect to the tool magazine, the displacement in the depth direction detected by the optical length measuring instrument appears large, making it easier to detect the circumferential displacement.

[0019] In one embodiment, a control unit is provided that determines the displacement direction of the tool holder with respect to the tool magazine based on the displacement in the depth direction.

[0020] According to such a configuration, it is possible for the control unit to know whether the tool holder has displaced in the axial direction and / or the circumferential direction with respect to the tool magazine (or both) without the user having to perform manual calculations.

[0021] In one embodiment, the control unit has a first model representing the relationship between the displacement in the depth direction, the axial displacement and the circumferential displacement of the tool holder with respect to the tool magazine, with reference to the center of the groove portion. The control unit sets an OK zone and a determination zone based on the first model. The OK zone is a region where the displacement in the depth direction includes zero, and the determination zone is a region where the displacement in the depth direction is at least larger than the OK zone. When the displacement in the depth direction is included in the OK zone, the control unit does not determine the displacement direction. When the displacement in the depth direction is included in the determination zone, the control unit determines the displacement direction.

[0022] According to such a configuration, a region where the displacement in the depth direction detected by the optical length measuring device is near zero is set as the OK zone, and the displacement direction is not determined. Thereby, in the determination of the displacement direction, the overlapping (interference) portion of the curvatures in the axial direction and the circumferential direction Radius can be excluded. The curvature in the axial direction Radius and the curvature in the circumferential direction Radius are such that as the displacement in the depth direction increases, the difference between them widens and they do not interfere with each other (do not overlap). A region where the displacement in the depth direction detected by the optical length measuring device is at least larger than the OK zone, that is, a region where the curvatures in the axial direction and the circumferential direction Radius do not interfere with each other is set as the determination zone, and the displacement direction is determined. Thereby, it is possible to more accurately estimate whether the tool holder has been displaced in either the axial direction or the circumferential direction (or both) with respect to the tool magazine.

[0023] In one embodiment, the control unit further sets an NG zone based on the first model. The NG zone is an area where the depth direction displacement is larger than the determination zone. When the depth direction displacement is included in the OK zone, the control unit continues the operation of the tool changer. When the depth direction displacement is included in the determination zone, the control unit determines the displacement direction and takes measures according to the displacement direction. When the depth direction displacement is included in the NG zone, the control unit stops the operation of the tool changer. The measures according to the displacement direction include correcting the posture of the tool holder with respect to the tool magazine.

[0024] According to such a configuration, when the depth direction displacement detected by the optical length measuring device is included in the OK zone, the displacement (positional deviation) of the tool holder with respect to the tool magazine is small, so the tool magazine operates as it is. When the depth direction displacement detected by the optical length measuring device is included in the NG zone, the displacement (positional deviation) of the tool holder with respect to the tool magazine is already an amount that cannot be corrected, so the tool magazine is stopped. When the depth direction displacement detected by the optical length measuring device is included in the determination zone, the displacement (positional deviation) of the tool holder with respect to the tool magazine may be an amount that can be corrected. Therefore, after determining the displacement direction of the tool holder with respect to the tool magazine, measures according to the determined displacement direction are taken. In some cases, the posture of the tool holder is corrected. Thus, by setting each zone according to the depth direction displacement, appropriate responses can be taken according to the depth direction displacement detected by the optical length measuring device.

[0025] In one embodiment, the control unit determines the displacement direction based on a second model representing the relationship between the rotation angle of the tool magazine and the depth direction displacement.

[0026] According to such a configuration, the modes of the second model are different when the tool holder is displaced axially and circumferentially with respect to the tool magazine. Therefore, based on the obtained mode of the second model, it can be easily determined whether the tool holder is displaced axially and / or circumferentially (or both) with respect to the tool magazine.

[0027] In one embodiment, when it is determined that the displacement direction is the axial direction, the control unit rotates the tool magazine in a small step in a forward and reverse alternating manner. On the other hand, when it is determined that the displacement direction is the circumferential direction, the control unit rotates the tool magazine more greatly compared to the former and then stops it, so as to control the rotation of the tool magazine.

[0028] According to such a configuration, an optimal posture correction (position adjustment) method can be applied according to the displacement direction of the tool holder with respect to the tool magazine.

[0029] In one embodiment, a reference portion is provided on the tool magazine. The optical length measuring device irradiates light on the reference portion to detect the displacement of the reference portion. The control unit zero-sets the depth direction displacement of the inner surface based on the displacement of the reference portion.

[0030] According to such a configuration, every time the optical length measuring device detects the displacement of the reference portion as the tool magazine rotates, the zero point of the depth direction displacement of the inner surface of the groove portion can be updated.

Advantages of the Invention

[0031] According to the present invention, it is possible to more accurately detect a posture defect of a tool holder held by a tool magazine.

Brief Description of the Drawings

[0032]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0033] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely illustrative in nature and is in no way intended to limit the present invention, its applications, or its uses.

[0034] FIG. 1 shows a tool changer 1. As shown in FIG. 1, the tool changer 1 is applied to a machine tool such as an NC milling machine. The tool changer 1 includes a motor 2, a tool magazine 10, a laser rangefinder 20 as an optical length measuring device, and a control unit 21. The tool magazine 10 is disk-shaped and rotatable about a central axis C. A tool holder 30 for holding a tool T is detachably gripped on the outer peripheral portion of the tool magazine 10. Hereinafter, with reference to the tool magazine 10, the axial direction of the tool magazine 10 is indicated by Z, the radial direction of the tool magazine 10 is indicated by R, and the circumferential direction of the tool magazine 10 is indicated by θ.

[0035] The tool magazine 10 has a magazine body 11 and a plurality of chucks 12 as tool gripping portions. The magazine body 11 is formed in a disk shape. The magazine body 11 is connected to the drive shaft of the motor 2. The magazine body 11 is rotatable about the central axis C by the drive of the motor 2.

[0036] Each chuck 12 is arranged at equal intervals in the circumferential direction on the outer peripheral portion of the magazine body 11. Each chuck 12 is formed in a substantially U shape when viewed axially, and is fixed to the magazine body 11 so that its opening faces the outer peripheral side. A tool holder 30 is detachably gripped by each chuck 12.

[0037] Figure 2 is a view taken in the direction of arrow II in Figure 1, showing the tool holder 30 held by the chuck 12 of the tool magazine 10. As shown in Figure 2, each chuck 12 holds the tool holder 30 by sandwiching the tool holder 30 from both circumferential sides by a pair of arms 13. The tool holder 30 is formed, for example, in a substantially cylindrical shape.

[0038] On the inner side in the circumferential direction of each arm 13, a tapered convex portion (claw portion) 14 is provided. On the outer peripheral surface 31 of the tool holder 30, a tapered concave portion (groove portion) 32 corresponding to the convex portion 14 is provided. The convex portion 14 and the concave portion 32 are fitted to each other.

[0039] As shown in Figure 1, the tool spindle (main spindle) 3 of the machine tool is arranged parallel to the tool magazine 10. The tool holder 30 is detachably attached to the tool spindle 3. The tool spindle 3 performs machining of a workpiece (not shown) by rotating the tool holder 30 holding the tool T.

[0040] The tool changer 1 performs the transfer of the tool holder 30 between the tool magazine 10 and the tool spindle 3. Specifically, when the tool magazine 10 rotates by the drive of the motor 2, the chuck 12 moves to the transfer position P1. On the other hand, the tool spindle 3 also moves from the machining position (not shown) to the transfer position P1 by an NC axis or the like.

[0041] The tool holder 30 is transferred between the tool magazine 10 and the tool spindle 3 at the transfer position P1. Specifically, the tool holder 30 attached to the tool spindle 3 is gripped (attached) by the empty chuck 12, and at the same time, the tool holder 30 gripped (attached) by another chuck 12 is detached and attached to the tool spindle 3.

[0042] As shown in FIGS. 1 and 2, when the tool holder 30 is gripped by the chuck 12 of the tool magazine 10, a groove portion 40 is provided in a facing portion (part) 33 that faces the outer peripheral side (radial outside). Note that the facing portion 33 is finish-machined.

[0043] As shown in FIG. 2, the groove portion 40 is formed in an elliptical spherical shape such that the radial direction of the tool magazine 10 is the depth direction. The contour of the opening edge 41 of the groove portion 40 is an elliptical shape having a major axis extending in the axial direction and a minor axis extending in the circumferential direction. Specifically, the opening edge 41 of the groove portion 40 is composed of two R50 curves extending in the axial direction and two R12 curves extending in the circumferential direction.

[0044] FIG. 3 shows the groove portion 40 three-dimensionally. The groove portion 40 has different curvatures in the depth direction (radial direction) in the axial direction and the circumferential direction. Radius Specifically, the curvature of the groove portion 40 in the depth direction in the circumferential direction Radius is smaller than the curvature of the groove portion 40 in the depth direction in the axial direction. Radius

[0045] More specifically, the curvature of the groove portion 40 in the depth direction in the axial direction Radius is R50. The curvature of the groove portion 40 in the depth direction in the circumferential direction Radius is R12. The inner surface 42 of the groove portion 40 is deepest at the central portion in the axial direction, while being shallowest (zero) at both end portions. Similarly, the inner surface 42 of the groove portion 40 is deepest at the central portion in the circumferential direction, while being shallowest (zero) at both end portions. Here, the inner surface 42 refers to the spherical surface that constitutes the inner side surface and the inner bottom surface of the groove portion 40.

[0046] The center O of the groove portion 40 is located at the central portion in the axial direction of the groove portion 40 and the central portion in the circumferential direction. In other words, the center O of the groove portion 40 is the intersection of the middle R50 curve and the middle R12 curve. The center O of the groove portion 40 is the deepest portion in the groove portion 40.

[0047] As shown in FIG. 1, the laser length measuring device 20 is arranged on the outer peripheral side (radially outside) of the tool magazine 10. As shown in FIGS. 1 and 2, the laser length measuring device 20 irradiates laser light (indicated by L) in the radial direction (depth direction) with respect to the center O of the inner surface 42 of the groove portion 40 in the tool holder 30 gripped by the chuck 12 of the tool magazine 10.

[0048] Specifically, as shown in FIG. 1, when the tool magazine 10 rotates by the drive of the motor 2, the tool holder 30 gripped by the chuck 12 moves to the length measuring position P2. The facing portion 33 (groove portion 40) of the tool holder 30 faces the laser length measuring device 20 at the length measuring position P2. At the length measuring position P2, the separation direction between the tool holder 30 and the laser length measuring device 20 is the radial direction.

[0049] The laser length measuring device 20 detects a depth direction displacement (radial direction displacement) dr, which is the distance from the reference position in the depth direction (radial direction) of the inner surface 42 of the groove portion 40, based on the reflected light when the inner surface 42 of the groove portion 40 is irradiated with laser light. The reference position is initially set when the tool changer 1 is installed.

[0050] As shown in FIG. 1, a reference portion S is provided at the tip of the chuck 12 of the tool magazine 10. The laser length measuring device 20 irradiates the reference portion S with laser light. The reference portion S is composed of a finished surface, a groove portion, a marker portion, or the like. The reference portion S may be provided on the magazine body 11 instead of the chuck 12. Further, the reference portion S may be provided on a measuring jig or the like attached to the tool magazine 10.

[0051] Specifically, when the tool magazine 10 rotates by the drive of the motor 2, the reference portion S moves to the length measuring position P2. The reference portion S faces the laser length measuring device 20 at the length measuring position P2. At the length measuring position P2, the separation direction between the reference portion S and the laser length measuring device 20 is the radial direction.

[0052] The laser length measuring device 20 detects a depth direction displacement (radial direction displacement, not shown) of the reference portion S based on the reflected light when the reference portion S is irradiated with laser light.

[0053] The control unit 21 is composed of, for example, a microcomputer and a program. The control unit 21 is connected to the motor 2 and the laser length measuring device 20.

[0054] The control unit 21 zero-sets the depth direction displacement (radial direction displacement) dr of the inner surface 42 of the groove portion 40 based on the depth direction displacement (radial direction displacement) of the reference portion S. That is, the control unit 21 updates the reference position (zero point) in the depth direction (radial direction) of the inner surface 42 of the groove portion 40.

[0055] Since the groove portion 40 is formed in an elliptical spherical shape, when the tool holder 30 is displaced from the reference position in at least one of the axial direction and the circumferential direction with respect to the tool magazine 10, that is, when a posture defect of the tool holder 30 with respect to the tool magazine 10 occurs, the inner surface 42 of the groove portion 40 is displaced in the depth direction (radial direction).

[0056] Here, the tool holder 30 hardly displaces in the depth direction (radial direction) with respect to the tool magazine 10. The tool holder 30 is usually a thick cylindrical shape with a uniform wall thickness over the entire circumference and is located at the gripping point (chuck 12) in the tool magazine 10, so thermal deformation and gripping deformation are unlikely to occur. Also, the tool magazine 10 is usually disc-shaped. For this reason, the tool holder 30 is unlikely to displace in the depth direction (radial direction) with respect to the tool magazine 10.

[0057] That is, the laser length measuring device 20 detects the displacement amount including the axial direction displacement dz and the circumferential direction displacement dθ of the tool holder 30 with respect to the tool magazine 10 by detecting the depth direction displacement (radial direction displacement) dr of the inner surface 42 of the groove portion 40.

[0058] Furthermore, since the curvature of the groove portion 40 in the depth direction Radius is different between the axial direction and the circumferential direction, the magnitude of the depth direction displacement dr detected by the laser length measuring device 20 is different when the tool holder 30 is displaced axially and circumferentially with respect to the tool magazine 10.

[0059] Specifically, the curvature in the depth directionRadius When the tool holder 30 is displaced in the large axial direction, the depth direction displacement dr detected by the laser length measuring instrument 20 is relatively small. On the other hand, the curvature in the depth direction Radius When the tool holder 30 is displaced in the small circumferential direction of the curvature, the depth direction displacement dr detected by the laser length measuring instrument 20 is relatively large.

[0060] Based on the depth direction displacement (radial displacement) dr detected by the laser length measuring instrument 20, the control unit 21 determines the displacement direction (axial direction or circumferential direction) of the tool holder 30 with respect to the tool magazine 10.

[0061] The control unit 21 has a first model M1. As shown in FIG. 4, the first model M1 represents the relationship between the depth direction displacement (radial displacement) dr of the inner surface 42 of the groove portion 40 detected by the laser length measuring instrument 20, the axial displacement dz and the circumferential displacement dθ of the tool holder 30 with respect to the tool magazine 10, when the center (innermost part) O of the groove portion 40 is used as a reference. The first model M1 is obtained by transferring the inner surface 42 of the groove portion 40.

[0062] As shown in FIG. 4, the first model M1 includes an R50 curve and an R12 curve. The horizontal axis represents the axial displacement dz [mm] and the circumferential displacement dθ [mm]. The axial displacement dz corresponds to the R50 curve. The circumferential displacement dθ corresponds to the R12 curve. The vertical axis represents the depth direction displacement dr [μm].

[0063] As shown in FIG. 4, based on the first model M1, the control unit 21 sets an "OK zone", a "Judgment zone", and an "NG zone" according to the depth direction displacement (radial displacement) dr.

[0064] The OK zone is an area where the depth direction displacement (radial displacement) dr includes zero. The Judgment zone is an area where the depth direction displacement dr is at least larger than the OK zone. The NG zone is an area where the depth direction displacement dr is larger than the Judgment zone.

[0065] In this embodiment, the depth direction displacement dr is set such that it is in the OK zone when it is less than 3 μm, in the determination zone when it is 3 μm or more and less than 25 μm, and in the NG zone when it is 25 μm or more.

[0066] Further, based on the first model M1, the control unit 21 sets an "OK zone", a "determination (correction) zone", and an "NG zone" according to the axial direction displacement dz and the circumferential direction displacement dθ. In this embodiment, the axial direction displacement dz and the circumferential direction displacement dθ are set such that they are in the OK zone when they are less than 0.5 mm, in the determination zone when they are 0.5 mm or more and less than 0.8 mm, and in the NG zone when they are 0.8 mm or more.

[0067] The control unit 21 has a second model M2. As shown in FIGS. 5 and 6, the second model M2 represents the relationship between the rotation angle Φ of the tool magazine 10 and the depth direction displacement (radial direction displacement) dr.

[0068] FIG. 5 shows the case where the tool holder 30 is displaced only in the axial direction with respect to the tool magazine 10. The horizontal axis represents the rotation angle Φ [°] of the tool magazine 10. The vertical axis represents the depth direction displacement dr [μm]. As shown in FIG. 5, in the second model M2, the graph (curve) M2z obtained when the tool holder 30 is displaced only in the axial direction with respect to the tool magazine 10 is simply translated in the vertical axis direction with respect to the graph (curve) M2o obtained when the tool holder 30 is not displaced at all with respect to the tool magazine 10 (only the depth direction displacement dr has changed).

[0069] FIG. 6 shows the case where the tool holder 30 is displaced only in the circumferential direction with respect to the tool magazine 10. The horizontal axis represents the rotation angle Φ [°] of the tool magazine 10. The vertical axis represents the depth direction displacement dr [μm]. As shown in FIG. 6, in the second model M2, the graph (curve) M2θ obtained when the tool holder 30 is displaced only in the circumferential direction with respect to the tool magazine 10 is simply translated in the horizontal axis direction with respect to the graph (curve) M2o obtained when the tool holder 30 is not displaced at all with respect to the tool magazine 10.

[0070] When the tool holder 30 is displaced in both the axial direction and the circumferential direction with respect to the tool magazine 10, a graph obtained by synthesizing the graphs M2z and M2θ shown in FIGS. 5 and 6 is obtained.

[0071] Based on the second model M2, the control unit 21 determines the displacement direction (axial direction or circumferential direction) of the tool holder 30 with respect to the tool magazine 10.

[0072] When it is determined that the displacement direction is the axial direction (see FIG. 5), the control unit 21 controls the rotation of the tool magazine 10 (motor 2) to rotate the tool magazine 10 in a small step (for example, about ±2°) in forward and reverse alternately. As a result, a small shake occurs in the entire system including the tool magazine 10 and the tool holder 30, and the tapered convex portions 14 on the pair of arms 13 of the chuck 12 are more likely to fit into the tapered concave portions 32 on the outer peripheral surface 31 of the tool holder 30 (see FIG. 2). Then, the tool holder 30 is position-adjusted in the axial direction.

[0073] On the other hand, when it is determined that the displacement direction is the circumferential direction (see FIG. 6), the control unit 21 controls the rotation of the tool magazine 10 (motor 2) to rotate the tool magazine 10 by a larger amount (for example, 90° or more) compared to the former (when it is determined that the displacement direction is the axial direction) and then stop. As a result, an inertial force in the circumferential direction is applied to the tool holder 30, and the circumferential displacement is suppressed. When the tool holder 30 is displaced in the circumferential direction, the tool holder 30 is likely to move to a position where it fits well while being held by the tool magazine 10. Then, the tool holder 30 is position-adjusted in the circumferential direction.

[0074] When the depth direction displacement (radial displacement) dr is included in the OK zone, that is, when the depth direction displacement dr is less than 3 μm, the axial displacement dz and the circumferential displacement dθ are included in the OK zone of less than 0.5 mm. At this time, the control unit 21 does not determine the displacement direction and continues the operation of the tool changer 1. It should be noted that when the depth direction displacement (radial displacement) dr is included in the OK zone, it has been confirmed by the inventors of the present application that there is no problem with the posture of the tool holder 30 with respect to the tool magazine 10.

[0075] When the depth direction displacement dr is included in the NG zone, that is, when the depth direction displacement dr is 25 μm or more, the axial displacement dz and the circumferential displacement dθ are included in the NG zone of 0.8 mm or more. At this time, the control unit 21 does not determine the displacement direction and stops the operation of the tool changer 1. Specifically, the control unit 21 stops the rotation of the tool magazine 10 by stopping the drive of the motor 2.

[0076] When the depth direction displacement dr is included in the determination zone, that is, when the depth direction displacement dr is 3 μm or more and less than 25 μm, the control unit 21 determines the displacement direction and takes measures according to the determined displacement direction. The measures according to the displacement direction include correcting the posture of the tool holder 30 with respect to the tool magazine 10.

[0077] When the depth direction displacement dr is 3 μm or more and less than 5 μm in the determination zone, the control unit 21 determines that the displacement direction is the axial direction. Then, the control unit 21 corrects the posture (position adjustment) in the axial direction of the tool holder 30 with respect to the tool magazine 10 by rotating the tool magazine 10 in small increments in the forward and reverse directions alternately. The control unit 21 repeats this several times until the depth direction displacement dr detected by the laser length measuring device 20 is included in the OK zone.

[0078] Note that as a result of the repetition, if the depth direction displacement dr is included in the OK zone, the operation shifts to the normal operation. On the other hand, if the depth direction displacement dr is not included in the OK zone (if the posture cannot be corrected), the rotation of the tool magazine 10 is stopped (the operation of the tool changer 1 is stopped). The number of repetitions can be arbitrarily set.

[0079] When the depth-direction displacement dr is 5 μm or more and less than 13 μm within the determination zone, the control unit 21 determines that the displacement direction is the circumferential direction. Then, the control unit 21 performs a circumferential attitude correction (position adjustment) of the tool holder 30 with respect to the tool magazine 10 by rotating the tool magazine 10 greatly and then stopping it. The control unit 21 repeats this several times until the depth-direction displacement dr detected by the laser displacement meter 20 is included in the OK zone.

[0080] Note that when the depth-direction displacement dr is 5 μm or more and less than 13 μm, assuming that an error occurs only in the circumferential direction, the maximum mounting error is 0.8°, which is within a reasonable range. On the other hand, when the depth-direction displacement dr is 5 μm or more and less than 13 μm, assuming that an error occurs only in the axial direction, the maximum mounting error is 0.8 mm, which is an unacceptable error amount from the perspective of the taper fitting (protrusion 14, recess 32) between the arm 13 of the chuck 12 of the tool magazine 10 and the tool holder 30. In this case, it can be determined that dust is attached to one of the tapered protrusion 14 and recess 32. At this time, the tool holder 30 is simply clamped by the arm 13 of the tool magazine 10, and it is considered that a significant error has occurred in the axial direction (or also in the circumferential direction).

[0081] When the depth-direction displacement dr is 13 μm or more and less than 25 μm within the determination zone, the control unit 21 first determines the displacement direction of the tool holder 30 with respect to the tool magazine 10 based on the second model M2. Then, when the control unit 21 determines that the displacement direction is the circumferential direction based on the second model M2, the control unit 21 performs a circumferential attitude correction (position adjustment) of the tool holder 30 with respect to the tool magazine 10 by rotating the tool magazine 10 greatly and then stopping it. The control unit 21 repeats this several times until the depth-direction displacement dr detected by the laser displacement meter 20 is included in the OK zone. On the other hand, when the control unit 21 determines that the displacement direction is the axial direction based on the second model M2, the control unit 21 stops the rotation of the tool magazine 10 (stops the operation of the tool changer 1) by stopping the drive of the motor 2.

[0082] Incidentally, as a method for more accurately determining the displacement direction (error direction), there is the following method. By rotating (turning) the tool magazine 10 more than the curvature Radius R12 in the circumferential direction of the elliptical spherical groove portion 40, the elliptical shape in the circumferential direction of the groove portion 40 can be recognized by a line. Thereby, the mounting position of the tool holder 30 with respect to the tool magazine 10 can be grasped more accurately, and the error direction (axial direction or circumferential direction) can be specified.

[0083] As described above, according to the present embodiment, since the curvature in the depth direction (radial direction) of the groove portion 40 Radius differs between the axial direction and the circumferential direction, as shown in FIG. 4, the magnitude of the depth direction displacement (radial direction displacement) dr detected by the laser length measuring instrument 20 is different between the case where the tool holder 30 is displaced axially with respect to the tool magazine 10 and the case where it is displaced circumferentially.

[0084] Thus, based on the magnitude of the depth direction displacement dr detected by the laser length measuring instrument 20, it is possible to estimate whether the tool holder 30 has been displaced axially and / or circumferentially with respect to the tool magazine 10 (or both).

[0085] Therefore, it is possible to more accurately detect a posture defect of the tool holder 30 held by the tool magazine 10.

[0086] The circumferential displacement dθ of the tool holder 30 with respect to the tool magazine 10 is usually more difficult to detect than the axial displacement dz of the tool holder 30 with respect to the tool magazine 10. Specifically, when the rotation radius of the tool magazine 10 is small, the rotation of the tool magazine 10 is included in the circumferential displacement dθ, making it difficult to detect the circumferential displacement dθ. Also, when the tool holder 30 is cylindrical, the R shape of the side surface of the tool holder 30 is included in the circumferential displacement dθ, making it difficult to detect the circumferential displacement dθ.

[0087] According to the present embodiment, the groove portion 40 has a curvature in the depth direction in the circumferential directionRadius is formed so as to be small (R12). As a result, when the tool holder 30 is displaced in the circumferential direction with respect to the tool magazine 10, as shown in FIG. 4, the depth-direction displacement dz detected by the laser displacement meter 20 appears large, making it easier to detect the circumferential displacement dθ.

[0088] Whether the tool holder 30 is displaced in either the axial direction or the circumferential direction (or both) with respect to the tool magazine 10 can be known by the control unit 21 without the user having to perform manual calculations.

[0089] A region where the depth-direction displacement dr detected by the laser displacement meter 20 is near zero is set as the OK zone, and the displacement direction is not determined. As a result, in determining the displacement direction, the overlapping (interfering) portions of the curvatures in the axial direction and the circumferential direction Radius can be excluded. As shown in FIG. 4, as the depth-direction displacement dr detected by the laser displacement meter 20 increases, the difference between the curvature in the axial direction Radius and the curvature in the circumferential direction Radius widens and they no longer interfere with each other (no longer overlap). For a region where the depth-direction displacement dr detected by the laser displacement meter 20 is at least larger than the OK zone, that is, a region where the curvatures in the axial direction and the circumferential direction Radius do not interfere with each other, the displacement direction is determined as the determination zone. As a result, it is possible to more accurately estimate whether the tool holder 30 is displaced in either the axial direction or the circumferential direction (or both) with respect to the tool magazine 10.

[0090] When the depth-direction displacement dr detected by the laser length measuring device 20 is included in the OK zone, the displacement (misalignment) of the tool holder 30 with respect to the tool magazine 10 is small, so the tool changer 1 is operated as it is. When the depth-direction displacement dr detected by the laser length measuring device 20 is included in the NG zone, the displacement (misalignment) of the tool holder 30 with respect to the tool magazine 10 is no longer a correctable amount, so the tool changer 1 is stopped. When the depth-direction displacement dr detected by the laser length measuring device 20 is included in the determination zone, the displacement (misalignment) of the tool holder 30 with respect to the tool magazine 10 may be a correctable amount. Therefore, after determining the displacement direction of the tool holder 30 with respect to the tool magazine 10, a measure corresponding to the determined displacement direction is taken, and in some cases, the posture of the tool holder 30 is corrected. Thus, by setting each zone according to the depth-direction displacement dr detected by the laser length measuring device 20, an appropriate response according to the depth-direction displacement dr can be taken.

[0091] As shown in FIGS. 5 and 6, the modes of the second model M2 are different between the case where the tool holder 30 is displaced axially with respect to the tool magazine 10 and the case where it is displaced circumferentially. Therefore, based on the obtained mode of the second model M2, it is possible to easily know whether the tool holder 30 is displaced axially and / or circumferentially with respect to the tool magazine 10 (or displaced in both directions).

[0092] An optimal posture correction (position adjustment) method can be applied according to the displacement direction of the tool holder 30 with respect to the tool magazine 10.

[0093] Each time the laser length measuring device 20 detects the displacement of the reference portion S as the tool magazine 10 rotates, the zero point (reference position) of the depth-direction displacement dr of the inner surface 42 of the groove portion 40 can be updated.

[0094] As described above, the present invention has been described with reference to the preferred embodiments, but such descriptions are not limiting matters, and of course, various modifications are possible.

[0095] The determination of the displacement direction of the tool holder 30 with respect to the tool magazine 10 or the posture correction of the tool holder 30 by the rotation control of the tool magazine 10 may be manually performed by the user himself / herself without depending on the command of the control unit 21.

[0096] In this embodiment, the curvature in the depth direction in the axial direction of the groove portion 40 Radius is set to R50, and the curvature in the depth direction in the circumferential direction of the groove portion 40 Radius is set to R12, but it is not limited thereto. For example, the curvature in the depth direction in the axial direction of the groove portion 40 Radius may be set to R12, and the curvature in the depth direction in the circumferential direction of the groove portion 40 Radius may be set to R50. Also, the numerical value of the curvature Radius may be arbitrarily set.

Industrial Applicability

[0097] Since the present invention can be applied to a tool changing device, it is extremely useful and has high industrial applicability.

Explanation of Reference Numerals

[0098] R Depth direction (radial direction) Z Axis direction θ Circumferential direction dr Depth direction displacement (radial direction displacement) dz Axis direction displacement dθ Circumferential direction displacement M1 First model M2 Second model R50 Curvature Radius (Curve) R12 Curvature Radius (Curve) Φ Rotation angle OK OK zone NG NG zone JUD Judgment zone L Laser beam T Tool S Reference part O Center 1 Tool changing device 3 Tool spindle 10 Tool magazine 11 Magazine body 12 Chuck 20 Laser length measuring device (optical length measuring device) 21 Control unit 30 Tool holder 33 Opposing surface (part) 40 Groove part 41 Opening edge 42 Inner surface

Claims

1. A tool magazine in which a tool holder is detachably gripped on an outer peripheral portion, and an optical length measuring device disposed on the outer peripheral side of the tool magazine, wherein the tool holder is provided with a groove portion formed in an elliptical spherical shape at a portion facing the outer peripheral side when gripped by the tool magazine, the groove portion has different radii of curvature in the depth direction in the axial direction and the circumferential direction of the tool magazine, the optical length measuring device irradiates light onto the inner surface of the groove portion in the tool holder gripped by the tool magazine to detect a displacement in the depth direction of the inner surface, and when the tool holder is displaced with respect to the tool magazine in at least one of the axial direction and the circumferential direction, the inner surface is displaced in the depth direction, a tool changer.

2. In the tool changer according to claim 1, the groove portion has a smaller radius of curvature in the depth direction in the circumferential direction than the radius of curvature in the depth direction in the axial direction, a tool changer.

3. In the tool changer according to claim 1 or 2, a control unit for determining a displacement direction of the tool holder with respect to the tool magazine based on the displacement in the depth direction is provided, a tool changer.

4. In the tool changer according to claim 3, the control unit has a first model representing a relationship between the displacement in the depth direction, the axial displacement and the circumferential displacement of the tool holder with respect to the tool magazine when based on the center of the groove portion, the control unit sets an OK zone and a determination zone based on the first model, the OK zone is a region including zero displacement in the depth direction, the determination zone is a region where the displacement in the depth direction is at least larger than the OK zone, When the depth direction displacement is included in the OK zone, the control unit does not determine the displacement direction. When the depth direction displacement is included in the determination zone, the control unit determines the displacement direction. A tool changing device.

5. In the tool changing device according to claim 4, The control unit further sets an NG zone based on the first model, The NG zone is a region where the depth direction displacement is larger than the determination zone, When the depth direction displacement is included in the OK zone, the control unit continues the operation of the tool changing device. When the depth direction displacement is included in the determination zone, the control unit determines the displacement direction and takes measures according to the displacement direction. When the depth direction displacement is included in the NG zone, the control unit stops the operation of the tool changing device. The measures according to the displacement direction include posture correction of the tool holder with respect to the tool magazine. A tool changing device.

6. In the tool changing device according to any one of claims 3 to 5, The control unit determines the displacement direction based on a second model representing the relationship between the rotation angle of the tool magazine and the depth direction displacement. A tool changing device.

7. In the tool changing device according to any one of claims 3 to 6, When it is determined that the displacement direction is the axial direction, the control unit rotates the tool magazine in a small step in a forward and reverse alternating manner. When it is determined that the displacement direction is the circumferential direction, the control unit rotates the tool magazine larger than the former and then stops, so as to control the rotation of the tool magazine. A tool changing device.

8. In the tool changing device according to any one of claims 3 to 7, A reference part is provided on the tool magazine, The optical length measuring device detects the displacement of the reference part by irradiating light to the reference part. A tool changing device in which the control unit zero-sets the displacement in the depth direction of the inner surface based on the displacement of the reference unit.

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