Workpiece automatic exchange device and workpiece processing method

Abstract

To provide a workpiece automatic exchange device which can be installed in a compact space.SOLUTION: A workpiece automatic exchange device 1 includes: a workpiece stocker 6 on which a plurality of workpieces W1, W3 are placed; and a multi-joint robot arm 7 which delivers the workpieces W1, W3 between the workpiece stocker 6 and a machine tool 2. The workpiece stocker 6 has: a hollow enclosing frame part 8 extending in a vertical direction; and a ceiling part 9 provided at an upper end of the enclosing frame part 8. The multi-joint robot arm 7 is attached to the ceiling part 9 so as to extend downward from the ceiling part 9.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an automatic workpiece exchanger and a method for machining a workpiece using the workpiece exchanger. [Background technology]

[0002] In machining sites where workpieces are machined using machine tools such as machining centers, the machine tools are often operated in a mixture of cases where a large number of identical workpieces are machined (i.e., when a large number of workpieces are machined in one lot) and cases where small numbers of different types of workpieces are machined (i.e., when there are many types of workpieces and a small number of workpieces are machined per lot).

[0003] Here, when machining a large number of identical workpieces, the shape of the workpieces machined by the machine tool is always the same, so after machining a workpiece with the machine tool, the task of changing the workpiece on the machine tool to machine the next workpiece is basically the same action repeated.For this reason, by equipping the machine tool with a work stocker and a robot (articulated robot arm) and teaching the robot the task of changing the workpiece between the machine tool and the work stocker, it is possible to operate the machine tool automatically without human intervention.

[0004] On the other hand, when machining a small number of workpieces of various types, the shape of the next workpiece to be machined changes after machining a small number of workpieces. In this case, if you try to use a robot to change the workpiece, you need to change the robot's hand according to the shape of the workpiece, or re-teach the robot according to the shape of the workpiece, which is cumbersome. Therefore, when machining a small number of workpieces of various types, the workpiece change is performed by hand each time.

[0005] Against this technical background, in recent years, in order to improve the work efficiency of machine tools such as machining centers, an automatic work exchange device has been proposed in which a work stocker is placed adjacent to the machine tool and an articulated robot arm is provided to transfer workpieces between the work stocker and the machine tool (for example, Patent Document 1).

[0006] In the automatic workpiece exchange device of Patent Document 1, the workpiece stocker has a pedestal on which a plurality of workpieces are placed. The articulated robot arm is attached to the upper surface of the pedestal so as to extend upward from the pedestal constituting the workpiece stocker.

[0007] The automatic workpiece exchange device in Patent Document 1 uses an articulated robot arm to grasp an unmachined workpiece placed on a pedestal and automatically set it on the machine tool, and also uses an articulated robot arm to grasp a machined workpiece that has completed machining on the machine tool and carry it to the pedestal, making it possible to automate the machine tool when machining multiple identical workpieces. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2019-150894 A (Fig. 8) Summary of the Invention [Problem to be solved by the invention]

[0009] In the automatic workpiece exchange device of Patent Document 1, multiple workpieces are placed on a pedestal constituting a work stocker, and an articulated robot arm is attached to the upper surface of the same pedestal. Therefore, the inventors of the present application have noticed that the installation space for the automatic workpiece exchange device is large.

[0010] The inventors of the present application then came up with the idea that if a ceiling portion was provided at the upper end of a hollow enclosing frame portion extending in the vertical direction, and the articulated robot arm was attached to the ceiling portion so as to extend downward from the ceiling portion, the articulated robot arm and work stocker could be positioned by efficiently utilizing the space extending in the vertical direction, and therefore the automatic work exchange device could be installed in a compact space.

[0011] Furthermore, the automatic workpiece exchange device of Patent Document 1 directly grips the workpiece with an articulated robot arm when performing workpiece exchange between the machine tool and the workpiece stocker, which necessitates changing the hand at the tip of the articulated robot arm according to the shape of the workpiece and recreating the teaching program for the workpiece exchange operation by the articulated robot arm according to the shape of the workpiece, which is problematic in that it is cumbersome.

[0012] Furthermore, when switching from unmanned operation, in which the automatic workpiece exchanger exchanges the workpieces of the machine tool, to manned operation, in which the workpieces of the machine tool are exchanged by hand, if the automatic workpiece exchanger (workpiece stocker and articulated robot arm) remains installed in front of the machine tool, it is difficult for the worker to approach the machine tool, and it becomes an obstacle to the workpiece exchange operation. Therefore, if the automatic workpiece exchanger is moved from in front of the machine tool to another location, the worker can easily approach the machine tool, but when the automatic workpiece exchanger is then installed again in front of the machine tool to switch from manned operation to unmanned operation, the positional relationship of the automatic workpiece exchanger to the machine tool is not constant, and it becomes necessary to re-teach the workpiece exchange operation by the articulated robot arm. However, teaching the articulated robot arm is not easy, and it takes a certain amount of effort and labor costs to train skilled technicians to teach the articulated robot arm. Even if there is a skilled technician in teaching an articulated robot arm, teaching it every time is time-consuming, and there is also the problem that the accuracy of teaching varies depending on the technician.

[0013] An object of the present invention is to provide an automatic workpiece exchange device that can be installed in a compact space. [Means for solving the problem]

[0014] In order to solve the above problems, the present invention provides an automatic workpiece exchange device having the following configuration. [Configuration 1] An automatic workpiece exchange device having a workpiece stocker arranged adjacent to a machine tool and on which a plurality of workpieces are placed, and a multi-joint robot arm for transferring the workpieces between the workpiece stocker and the machine tool, The work stocker has a hollow surrounding frame portion extending in a vertical direction and a ceiling portion provided at an upper end of the surrounding frame portion, The automatic workpiece exchange device is characterized in that the articulated robot arm is attached to the ceiling portion so as to extend downward from the ceiling portion.

[0015] When this configuration is adopted, the articulated robot arm is attached to the ceiling so as to extend downward from the ceiling provided at the upper end of the hollow enclosing frame extending in the vertical direction of the work stocker, so that the articulated robot arm and the work stocker can be arranged by efficiently utilizing the vertically extending space, making it possible to install the automatic work exchange device in a compact space.

[0016] [Configuration 2] the articulated robot arm includes a base fixed to the ceiling, a swivel table connected to a lower side of the base so as to be rotatable about a vertical axis, and a first arm connected to a lower side of the swivel table so as to be rotatable about a horizontal axis, The automatic workpiece exchange device according to configuration 1, wherein the workpiece stocker is configured such that, when viewed from above, the plurality of workpieces are arranged in a ring or partial ring shape centered on the rotation center of the swivel base of the articulated robot arm and placed thereon.

[0017] When this configuration is adopted, multiple workpieces are placed in a ring or partial ring shape centered on the center of rotation of the swivel base of the articulated robot arm, making it possible to easily manage the operation of the articulated robot arm when it is holding those workpieces.

[0018] [Configuration 3] The surrounding frame portion is formed in a regular polygonal shape or a circular shape when viewed from above, 3. The automatic workpiece exchange device according to configuration 2, wherein the center of rotation of the swivel base of the articulated robot arm is located at the center of the enclosing frame portion when viewed from above.

[0019] When this configuration is adopted, the articulated robot arm rotates around the center of the enclosing frame, making it possible to utilize the space inside the enclosing frame particularly efficiently and making the automatic workpiece exchange device particularly compact.

[0020] [Configuration 4] The automatic workpiece exchange device of any one of configurations 1 to 3, wherein the workpiece stocker has a structure that connects the space outside the enclosing frame portion with the space inside the enclosing frame portion so that an operator can place the workpiece on the workpiece stocker from outside the enclosing frame portion and remove the workpiece placed on the workpiece stocker from outside the enclosing frame portion.

[0021] When this configuration is adopted, an operator can place the unmachined workpiece on the work stocker from outside the enclosing frame, and can also remove the machined workpiece placed on the work stocker from outside the enclosing frame, making it possible for the operator to safely and easily perform tasks such as replacing workpieces in the work stocker without entering the working space of the articulated robot arm (the space inside the enclosing frame of the work stocker).

[0022] [Configuration 5] The automatic workpiece exchange device according to any one of configurations 1 to 4, wherein the workpiece stocker has a bracket extending horizontally from the lower part of the enclosing frame portion towards the machine tool, and a stocker side locating block fixed to the tip of the bracket, and the stocker side locating block is connected to a machine side locating block fixed to the lower part of the machine tool, thereby making it possible to position the workpiece stocker relative to the machine tool.

[0023] When this configuration is adopted, the work stocker can be positioned relative to the machine tool by connecting the stocker-side locating block at the tip of the bracket extending horizontally from the bottom of the surrounding frame of the work stocker to the machine-side locating block fixed to the bottom of the machine tool. Therefore, the positional relationship of the work stocker to the machine tool can be fixed, and once teaching of the articulated robot arm is performed in that positional relationship, there is no need to re-teach the articulated robot arm even when the work stocker is temporarily moved away from the machine tool and then installed again adjacent to the machine tool.

[0024] [Configuration 6] the work stocker has a plurality of work holders for individually holding the plurality of workpieces, and is configured so that each of the workpieces is placed via each of the work holders; 6. The automatic workpiece exchange device according to any one of configurations 1 to 5, wherein the work holder has a flange portion having a circumferential groove formed on its outer periphery for gripping by the articulated robot arm, a clamp portion provided on one axial side of the flange portion for clamping and fixing the workpiece, and a tapered shank portion provided on the other axial side of the flange portion.

[0025] When this configuration is adopted, when exchanging a workpiece between the machine tool and the work stocker, the articulated robot arm does not directly grip the workpiece, but rather grips the work holder that holds the workpiece. Therefore, even when machining a variety of workpieces, it is efficient because there is no need to replace the hand at the end of the articulated robot arm according to the shape of each workpiece, or to re-create the teaching program for the workpiece exchange operation by the articulated robot arm according to the shape of each workpiece.

[0026] [Configuration 7] The automatic workpiece exchange device according to configuration 6, wherein the tapered shank portion is a hollow cylindrical HSK shank having a conical outer circumferential surface with a 1 / 10 gradient.

[0027] By adopting this configuration, since the HSK shank is standardized as a tool holder shank, it is easy to automate the operation of attaching the work holder to the machine tool, and since it is lighter and more compact than other types of shanks (7 / 24 taper shanks, etc.) that are standardized as tool holder shanks, it is possible to set a large number of workpieces to be placed on the work stocker.

[0028] The present invention also provides a method for machining a workpiece using the above-mentioned automatic workpiece exchange device, which has the following configuration. [Configuration 8] A method for machining a workpiece using the automatic workpiece exchange device according to configuration 6 or 7, the machine tool is a three-axis machining center having a main spindle that rotates about a vertical axis and a horizontal table that is movable relative to the main spindle, On the horizontal table, a first gripping device to which the work holder is removably attached with the axis of the tapered shank portion horizontal, a rotary table that rotates the first gripping device about a horizontal axis and positions it at an arbitrary angular position, and a second gripping device to which the work holder is removably attached with the axis of the tapered shank portion vertical are installed, A method of processing a workpiece, comprising: holding the work holder holding the workpiece in one of the first gripping device and the second gripping device, processing the workpiece, and then automatically transferring the work holder holding the workpiece from one of the first gripping device and the second gripping device to the other gripping device by the articulated robot arm, and further processing the workpiece.

[0029] When this configuration is adopted, the articulated robot arm automatically switches the work holder between the first and second gripping devices installed on the 3-axis machining center, making it possible to machine the workpiece in both positions, one where the axis of the tapered shank is horizontal, and one where the axis of the tapered shank is vertical.In the former position, the workpiece can be positioned at any angle on the rotary table, making it possible to use a 3-axis machining center while performing machining equivalent to that of a 5-axis machining center or multi-tasking machine. Effect of the Invention

[0030] In the automatic workpiece exchange device of the present invention, the articulated robot arm is attached to a ceiling section provided at the upper end of a hollow enclosing frame section extending in the vertical direction of the workpiece stocker so as to extend downward from the ceiling section, so that the articulated robot arm and the workpiece stocker can be disposed by efficiently utilizing the vertically extending space, thereby making it possible to install the automatic workpiece exchange device in a compact space. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a perspective view showing an automatic workpiece exchange device according to an embodiment of the present invention and a machine tool used in combination with the automatic workpiece exchange device; [Diagram 2] FIG. 2 is an enlarged perspective view of the automatic workpiece exchange device of FIG. [Diagram 3] Horizontal cross-sectional view of the automatic workpiece exchange device in Figure 2 [Figure 4] Cross-sectional view of the automatic workpiece exchange device in Figure 3, seen from above [Diagram 5] An enlarged view of the workpiece placement tool shown in FIG. [Figure 6] Cross-sectional view taken along line VI-VI in Figure 5. [Figure 7] FIG. 7 is a perspective view of the workpiece placement tool shown in FIG. [Figure 8] FIG. 8 is a partial cross-sectional view showing a workpiece placed on the workpiece placement tool shown in FIG. 7 and a workpiece holder that holds the workpiece. [Figure 9]FIG. 2 is a cross-sectional view showing a state in which the automatic workpiece exchange device shown in FIG. 1 is positioned relative to a machine tool. [Figure 10] An enlarged view of the area around the connection between the stocker side locating block and the machine side locating block in Figure 9. [Figure 11] Cross-sectional view taken along line XI-XI in Figure 10. [Figure 12] FIG. 3 shows a state in which a workpiece (held by a work holder) is placed on the workpiece placement tool shown in FIG. 2 and the workpiece is held by the hand of an articulated robot arm. [Figure 13] A diagram showing the workpiece shown in Figure 12 being lifted by an articulated robot arm. [Figure 14] Top view of the articulated robot arm and workpiece shown in Fig. 13 [Figure 15] A front view of the internal machining space of the machine tool shown in Figure 1. [Figure 16] FIG. 16 shows the state after each workpiece shown in FIG. 15 is machined, the workpiece attached to the second gripping device is lifted by the articulated robot arm, and before it is removed from the machine tool. [Figure 17] FIG. 17 shows a state before the workpiece of the first gripping device is removed by the articulated robot arm and set in the second gripping device after the workpiece of the second gripping device shown in FIG. 16 has been lifted and removed from the machine tool. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] Fig. 1 shows an automatic workpiece exchanger 1 according to an embodiment of the present invention. The automatic workpiece exchanger 1 is a device used in combination with a machine tool 2 in order to automate the operation of the machine tool. In the figure, the machine tool 2 is a machining center that machines a workpiece W1 (see Fig. 8) based on a preset machining program, and more specifically, as shown in Fig. 9, is a three-axis machining center having a main spindle 64 that rotates about a vertical axis and a horizontal table 62 that is movable relative to the main spindle 64.

[0033] 1, the machine tool 2 has a splash guard 3 surrounding a machining space for a workpiece W1, a front opening 4 provided in the splash guard 3 for allowing the workpiece W1 before machining and the workpiece W3 after machining (see FIG. 12) to be taken in and out of the machining space, and a front door 5 for opening and closing the front opening 4. The automatic workpiece exchange device 1 has a workpiece stocker 6 arranged adjacent to the machine tool 2, and an articulated robot arm 7 for transferring the workpieces W1, W3 between the workpiece stocker 6 and the machine tool 2.

[0034] 2, the work stocker 6 has a hollow surrounding frame 8 extending in the vertical direction, and a ceiling 9 provided at the upper end of the surrounding frame 8. The surrounding frame 8 is formed in the shape of a regular polygon (a regular hexagon in the figure) prism when viewed from above. The surrounding frame 8 can also be formed in the shape of a regular octagon, square, or circle when viewed from above.

[0035] The surrounding frame section 8 has a plurality of vertical frames 10 extending in the up-down direction and a plurality of horizontal frames 11 extending in the horizontal direction. The multiple vertical frames 10 are arranged at positions corresponding to the vertices of a regular polygon (a regular hexagon in the figure). The horizontal frames 11 are arranged to bridge between adjacent vertical frames 10 so as to correspond to the sides of the regular polygon, and both ends of each horizontal frame 11 are fixed to the vertical frames 10. The lower ends of the multiple vertical frames 10 are connected to each other by a base plate 12.

[0036] The ceiling part 9 is fixed to the upper ends of the vertical frames 10 via the inclined frames 13. The inclined frames 13 are provided at an angle from the upper end of the vertical frame 10 toward the center of a regular polygon (a regular hexagon in the figure) from the upper end position, and the ceiling part 9 and the vertical frames 10 are fixed to the upper and lower ends of the inclined frames 13, respectively. That is, the inclined frames 13 are arranged so as to form the ridgeline of a regular polygonal truncated pyramid (a regular hexagonal truncated pyramid in the figure) that gradually shrinks upward. Here, the ceiling part 9 is fixed to the upper end of the vertical frame 10 via the inclined frames 13, but it is also possible to fix the ceiling part 9 directly to the upper end of the vertical frame 10. The ceiling part 9 is formed of a horizontal metal plate.

[0037] 4 and 5, a plurality of workpiece placement devices 15 on which workpieces W1, W3 (see FIG. 12) are placed are attached to the horizontal frame 11. As shown in FIG. 12, the workpieces W1, W3 are individually held by a plurality of work holders 14, and each of the workpieces W1, W3 is placed on each of the workpiece placement devices 15 via each of the work holders 14.

[0038] 8, the work holder 14 has a flange portion 17 having a circumferential groove 16 formed on its outer periphery, a clamp portion 18 provided on one axial side (upper side in the figure) of the flange portion 17, and a tapered shank portion 19 provided on the other axial side (lower side in the figure) of the flange portion 17. The circumferential groove 16 on the outer periphery of the flange portion 17 is a groove for gripping with a hand 47 at the tip of the articulated robot arm 7 shown in FIG.

[0039] As shown in FIG. 8, the clamping portion 18 has a pair of opposing clamping claws 21, 22 that clamp and fix a dovetail portion 20 (a dovetail-shaped portion) formed at one end of the workpiece W1. One of the pair of clamping claws 21, 22 is a fixed clamping claw 21 formed integrally with the flange portion 17, and the other is a movable clamping claw 22 that moves toward the fixed clamping claw 21 by tightening a clamping bolt 23. The tapered shank portion 19 employs a hollow cylindrical 1 / 10 tapered shank (so-called HSK shank) having a conical outer circumferential surface with a 1 / 10 gradient. A pair of key grooves 24 are formed at an interval of 180° at the tip of the tapered shank portion 19. In addition, a pair of axial grooves 25 are formed at positions corresponding to the key grooves 24 on the outer periphery of the flange portion 17. Here, an HSK shank is employed as the tapered shank portion 19, but a 7 / 24 tapered shank can also be employed.

[0040] 5 and 7, the workpiece placement tool 15 has a U-shaped portion 26 that opens horizontally toward the center of the surrounding frame portion 8 (the right side in the figures), and as shown in Fig. 6, the workpiece holder 14 can be received inside the U-shaped portion 26, and the upper surface of the U-shaped portion 26 can support the lower surface of the flange portion 17 of the workpiece holder 14. The workpiece placement tool 15 also has a rotation prevention fitting portion 27 inside the U-shaped portion 26 that fits into the key groove 24 at the tip of the tapered shank portion 19 of the workpiece holder 14, and the fit of this key groove 24 and the rotation prevention fitting portion 27 allows the workpiece holder 14 to be positioned around the vertical axis.

[0041] As shown in Fig. 4, the work stocker 6 is configured so that, when viewed from above, multiple workpieces W1, W3 are placed on the workpieces arranged in a partial ring shape centered on the rotation center O of the swivel base 41 (see Fig. 3) of the articulated robot arm 7. In the figure, workpiece placement devices 15 are provided only on some of the horizontal frames 11 that surround the swivel base 41 in a ring shape so that the multiple workpieces W1, W3 are arranged in a partial ring shape centered on the rotation center O of the swivel base 41, but it is also possible to provide workpiece placement devices 15 on all of the horizontal frames 11 that surround the swivel base 41 in a ring shape so that the multiple workpieces W1, W3 are arranged in a ring shape centered on the rotation center O of the swivel base 41.

[0042] 9 and 10, work stocker 6 has bracket 30 extending horizontally from the lower part of enclosing frame portion 8 towards machine tool 2, and stocker-side locating block 31 fixed to the tip of bracket 30. The base end of bracket 30 is fixed to base plate 12 of work stocker 6. In addition, machine-side locating block 32 is fixed to the lower part of machine tool 2.

[0043] As shown in Fig. 11, the stocker-side locating block 31 is an elongated member extending in the left-right direction facing the machine tool 2, and is formed with a pair of left and right pin holes 33 penetrating in the up-down direction. The machine-side locating block 32 is also an elongated member extending in the left-right direction facing the machine tool 2, and is formed with a pair of left and right pin holes 34 penetrating in the up-down direction. Then, the work stocker 6 (see Fig. 1) is moved relative to the machine tool 2 so that the stocker-side locating block 31 and the machine-side locating block 32 are lined up vertically, and then a locating pin 35 is inserted into the pin hole 33 of the stocker-side locating block 31 and the pin hole 34 of the machine-side locating block 32 to connect both blocks 31, 32, thereby making it possible to position the work stocker 6 relative to the machine tool 2.

[0044] 3, the articulated robot arm 7 is attached to the underside of the ceiling 9 so as to extend downward from the ceiling 9. The articulated robot arm 7 includes a base 40 fixed to the ceiling 9, a swivel base 41 connected to the underside of the base 40 so as to be rotatable about a vertical axis, a first arm 42 connected to the underside of the swivel base 41 so as to be rotatable about a horizontal axis, a second arm 43 connected to the tip of the first arm 42 so as to be rotatable about a horizontal axis, a third arm 44 connected to the tip of the second arm 43 so as to be rotatable about an axis in the longitudinal direction of the second arm 43, a fourth arm 45 connected to the tip of the third arm 44 so as to be rotatable about an axis perpendicular to the longitudinal direction of the third arm 44, a fifth arm 46 connected to the tip of the fourth arm 45 so as to be rotatable about an axis in the longitudinal direction of the fourth arm 45, and a hand 47 attached to the tip of the fifth arm 46.

[0045] Electric motors (not shown) that drive each joint axis are incorporated in the joint axis (vertical axis) between the base 40 and the swivel base 41, the joint axis (horizontal axis) between the swivel base 41 and the first arm 42, the joint axis (horizontal axis) between the first arm 42 and the second arm 43, the joint axis (longitudinal axis of the second arm 43) between the second arm 43 and the third arm 44, the joint axis (axis perpendicular to the longitudinal direction of the third arm 44) between the third arm 44 and the fourth arm 45, and the joint axis (longitudinal axis of the fourth arm 45) between the fourth arm 45 and the fifth arm 46.

[0046] 13 and 14, the hand 47 has a pair of opposing fingers 48 that are openable and closable so as to grip the work holder 14. The pair of fingers 48 are supported by a hand main body 49 fixed to the tip of the fifth arm 46 so as to be movable in a direction perpendicular to the longitudinal direction of the fifth arm 46. An actuator (not shown) that drives the pair of fingers 48 is incorporated in the hand main body 49.

[0047] 14, the surface of each finger 48 facing the other finger 48 is formed with an arcuate edge 50 that fits into the circumferential groove 16 (see FIG. 13) of the flange portion 17 of the work holder 14. Also, a positioning protrusion 51 that fits into the axial groove 25 (see FIG. 8) on the outer periphery of the flange portion 17 is provided midway on the arcuate edge 50.

[0048] As shown in FIG. 2, the work stocker 6 has an opening (a square opening surrounded by the horizontal frame 11 and the vertical frame 10) formed on the upper side of the horizontal frame 11 to which the work placement tool 15 is attached, which communicates with the space inside the enclosing frame 8 and the space outside the enclosing frame 8, and through this opening, an operator can place the work W1 before machining on the work stocker 6 from outside the enclosing frame 8, and can also remove the work W3 after machining placed on the work stocker 6 from outside the enclosing frame 8. It is preferable to adopt an articulated robot arm 7 that conforms to the collaborative operation requirements stipulated in the Japanese Industrial Standard JIS B8433-1:2015 "Robots and robotic devices - Safety requirements for industrial robots - Part 1: Robots" (a so-called collaborative robot) because this ensures the safety of the operator.

[0049] An example of the use of the above-mentioned automatic workpiece exchange device 1 will now be described.

[0050] First, the automatic workpiece exchange device 1 shown in Fig. 1 is installed in front of the front door 5 of the machine tool 2. Then, as shown in Fig. 9, the workpiece stocker 6 is positioned relative to the machine tool 2 by connecting a stocker-side locating block 31 at the tip of a bracket 30 extending from the bottom of the workpiece stocker 6 toward the machine tool 2 to a machine-side locating block 32 fixed to the bottom of the machine tool 2. Thereafter, as shown in Fig. 8, the unmachined workpiece W1 (held by the workpiece holder 14) is placed on each workpiece placement tool 15 of the workpiece stocker 6 shown in Fig. 2.

[0051] Thereafter, the automatic workpiece exchange device 1 and the machine tool 2 cooperate to perform automatic operation of machining the workpieces. That is, as shown in Fig. 12 to Fig. 14, the articulated robot arm 7 holds and lifts the unmachined workpiece W1 (here, the flange portion 17 of the workpiece holder 14 holding the workpiece W1) placed on the workpiece placement device 15 of the workpiece stocker 6 with the hand 47 at the tip, sets it on the machine tool 2 (see Fig. 1) and performs machining, and also holds the machined workpiece W3 that has been machined on the machine tool 2 (see Fig. 1) with the hand 47 at the tip of the articulated robot arm 7, carries it from the machine tool 2 to the workpiece stocker 6 and places it on the workpiece placement device 15. A specific example will be described.

[0052] As shown in Fig. 15, a horizontal table 62 that can be positioned at any position in the horizontal direction and a spindle 64 (see Fig. 9) that can be positioned at any position in the vertical direction are provided in the machining space of the machine tool 2 (space surrounded by the splash guard 3 in Fig. 1). A first gripping device 61 to which the work holder 14 is detachably attached with the axis of the tapered shank portion 19 horizontal, a rotary table 60 that rotates the first gripping device 61 about its horizontal axis to position it at any angle, and a second gripping device 63 to which the work holder 14 is detachably attached with the axis of the tapered shank portion 19 vertical are provided on the horizontal table 62. The first gripping device 61 is attached to the horizontal table 62 via the rotary table 60, and the second gripping device 63 is attached directly to the horizontal table 62.

[0053] Here, the first gripping device 61 is attached with the work holder 14 in a state of holding the work W1 before machining, and the second gripping device 63 is attached with the work holder 14 in a state of holding the work W2 (a work in the middle of machining) obtained by machining the side surface of the work W1 with the first gripping device 61. The work W1 attached to the first gripping device 61 via the work holder 14 can be machined at any position on the side surface of the work W1 by rotating the rotary table 60 to change the angle of the work W1. In this state, the machine tool 2 sequentially machines the side surface of the work W1 attached to the first gripping device 61 and the end surface (the upper surface in the figure) of the work W2 attached to the second gripping device 63.

[0054] Thereafter, as shown in FIG. 16, the articulated robot arm 7 grasps and lifts the work holder 14 holding the machined workpiece W3 (obtained by machining the end face of the workpiece W2 with the second gripping device 63; that is, the workpiece after machining with the machine tool 2) from the second gripping device 63, and removes the workpiece W3 (held by the work holder 14) from the machine tool 2 and places it on the workpiece placement device 15 shown in FIG. 12. Next, as shown in FIG. 17, the articulated robot arm 7 automatically transfers the work holder 14 holding the workpiece W2 from the first gripping device 61 to the second gripping device 63. Thereafter, the articulated robot arm 7 holds and lifts the unmachined workpiece W1 placed on the work placement device 15 shown in FIG. 12, inserts the workpiece W1 into the machine tool 2, and attaches it to the first gripping device 61 shown in FIG. 17.

[0055] 15, the first gripping device 61 is attached with the work holder 14 holding the workpiece W1 before machining, and the second gripping device 63 is attached with the work holder 14 holding the workpiece W2 in the middle of machining. After that, the machine tool 2 again sequentially machines the side surface of the workpiece W1 attached to the first gripping device 61 and the end surface of the workpiece W2 attached to the second gripping device 63. By repeating the above operations, the multiple workpieces W1 placed on the work stocker 6 can be automatically machined in sequence.

[0056] 3, in this automatic workpiece exchange device 1, the articulated robot arm 7 is attached to the ceiling part 9 provided at the upper end of the surrounding frame part 8 of the workpiece stocker 6 so as to extend downward from the ceiling part 9, so that the articulated robot arm 7 and the workpiece stocker 6 can be arranged by efficiently utilizing the space extending in the vertical direction. Therefore, the automatic workpiece exchange device 1 can be installed in a compact space.

[0057] In addition, because the articulated robot arm 7 is attached to the ceiling 9 of the work stocker 6, the electrical wiring for driving the articulated robot arm 7 can be arranged to extend upward from the ceiling 9 of the work stocker 6. This prevents the electrical wiring of the articulated robot arm 7 from getting in the way at the feet of the worker, making it easier for the worker to approach the machine tool 2 and perform work.

[0058] Furthermore, as shown in FIG. 4, in this automatic workpiece exchange device 1, multiple workpiece mounting devices 15 are mounted in a partial ring shape centered on the rotation center O of the rotating table 41 of the articulated robot arm 7, so that it is possible to easily manage the operation of the articulated robot arm 7 when holding the unmachined workpiece W1 mounted on each workpiece mounting device 15, and the operation of the articulated robot arm 7 when mounting the machined workpiece W3 on each workpiece mounting device 15.

[0059] Furthermore, as shown in FIG. 4, when viewed from above, the center of rotation O of the swivel base 41 of the articulated robot arm 7 is positioned at the center of the enclosing frame portion 8, making it possible to utilize the space inside the enclosing frame portion 8 particularly efficiently and making the automatic workpiece exchange device 1 particularly compact.

[0060] Furthermore, as shown in FIG. 2, this automatic work exchange device 1 is configured so that an operator can place the unmachined work W1 on the work stocker 6 from outside the enclosing frame 8, and can also remove the machined work W3 placed on the work stocker 6 from outside the enclosing frame 8. This enables an operator to safely and easily perform operations such as replacing the work W3 on the work stocker 6 without entering the working space of the articulated robot arm 7 (the space inside the enclosing frame 8 of the work stocker 6).

[0061] 9, this automatic workpiece exchange device 1 can position the workpiece stocker 6 relative to the machine tool 2 by connecting a stocker-side locating block 31 at the tip of a bracket 30 extending horizontally from the bottom of the surrounding frame portion 8 of the workpiece stocker 6 to a machine-side locating block 32 fixed to the bottom of the machine tool 2. Therefore, the positional relationship of the workpiece stocker 6 relative to the machine tool 2 can be fixed, and once teaching of the articulated robot arm 7 is performed in that positional relationship, even when the workpiece stocker 6 is temporarily moved to a location away from the machine tool 2 to perform manned operation in which the workpieces W1, W3 of the machine tool 2 are replaced by a human, and then the workpiece stocker 6 is again installed adjacent to the machine tool 2 to perform unmanned operation in which the articulated robot arm 7 replaces the workpieces W1, W3 of the machine tool 2.

[0062] Furthermore, when this automatic workpiece exchange device 1 performs the exchange operation of the workpieces W1, W3 between the machine tool 2 and the workpiece stocker 6 shown in FIG. 9, the articulated robot arm 7 does not directly grasp the workpieces W1, W3, but as shown in FIGS. 13 and 16, the articulated robot arm 7 grasps the workpiece holder 14 that holds the workpieces W1, W3. Therefore, even when machining a variety of workpieces W1, it is efficient because there is no need to replace the hand 47 at the tip of the articulated robot arm 7 according to the shape of each workpiece W1, W3, or to re-create a teaching program for the exchange operation of the workpieces W1, W3 by the articulated robot arm 7 according to the shape of each workpiece W1, W3.

[0063] In addition, as shown in Fig. 8, this automatic workpiece changer 1 employs a hollow cylindrical HSK shank having a conical outer circumferential surface with a 1 / 10 gradient as the tapered shank portion 19 of the workpiece holder 14, and since the HSK shank is standardized as a tool holder shank, it is easy to automate the operation of mounting the workpiece holder 14 on the machine tool 2 shown in Fig. 15. In addition, since the HSK shank is lighter and more compact than other types of shanks (7 / 24 tapered shanks, etc.) that are standardized as tool holder shanks, it is possible to set a large number of workpieces W1, W3 to be placed on the workpiece stocker 6 shown in Fig. 2.

[0064] Furthermore, when the workpiece W1 is machined by the above-mentioned method, it is possible to perform machining equivalent to that of a 5-axis machining center or a multi-tasking machine while using a 3-axis machining center as the machine tool 2 shown in Fig. 15. That is, the articulated robot arm 7 shown in Fig. 9 automatically switches the workpiece holder 14 between the first gripping device 61 and the second gripping device 63 shown in Fig. 15, so that the workpieces W1 and W2 can be machined in both a posture in which the axis of the tapered shank portion 19 is horizontal and a posture in which the axis of the tapered shank portion 19 is vertical, and in the former posture, the workpiece W1 can be positioned at any angle by the rotary table 60, so that it is possible to perform machining equivalent to that of a 5-axis machining center or a multi-tasking machine while using a 3-axis machining center, which is economical. [Explanation of symbols]

[0065] 1 Automatic workpiece exchange device 2 Machine tools 6 Work Stocker 7 Articulated Robot Arm 8 Enclosure 9 Ceiling 14 Work holder 16 Circumferential groove 17 Flange 18 Clamp section 19 Tapered shank 30 Bracket 31 Stocker side locating block 32 Machine side locating block 40 base 41 Swivel table 42 First Arm 60 Rotary Table 61 First gripping device 62 Horizontal Table 63 Second gripping device 64 Main axis O Rotation center of the swivel base W1, W2, W3 work

Claims

1. A machine tool (2) is arranged adjacent to the workpiece (W １ , W ３ A work stocker (6) on which the work (W) is placed, and a work stocker (6) and a machine tool (2) are arranged between the work stocker (6) and the machine tool (2). １ , W ３ In the automatic workpiece exchange device, The work stocker (6) has a hollow surrounding frame portion (8) extending in the vertical direction and a ceiling portion (9) provided at the upper end of the surrounding frame portion (8), The automatic workpiece exchange device is characterized in that the articulated robot arm (7) is attached to the ceiling portion (9) so as to extend downward from the ceiling portion (9).

2. The articulated robot arm (7) has a base (40) fixed to the ceiling (9), a swivel table (41) connected to the lower side of the base (40) so as to be rotatable about a vertical axis, and a first arm (42) connected to the lower side of the swivel table (41) so as to be rotatable about a horizontal axis, The workpiece stocker (6) is arranged in a ring or partial ring shape centered on the rotation center (O) of the rotating base (41) of the articulated robot arm (7) when viewed from above. １ , W ３ 2. The automatic workpiece exchange device according to claim 1, wherein the workpiece is configured to be mounted on the workpiece.

3. The surrounding frame portion (8) is formed in a regular polygonal shape or a circular shape when viewed from above, 3. The automatic workpiece exchange device according to claim 2, wherein a rotation center (O) of the rotating base (41) of the articulated robot arm (7) is disposed at the center of the surrounding frame portion (8) when viewed from above.

4. The work stocker (6) is configured such that an operator can place the work (W) on the work stocker (6) from outside the surrounding frame (8). １ ) is placed on the work stocker (6), and the work (W ３ 4. An automatic workpiece exchange device as described in any one of claims 1 to 3, having a structure in which the space outside the enclosing frame portion (8) is connected to the space inside the enclosing frame portion (8) so that an operator can remove a workpiece from outside the enclosing frame portion (8).

5. 4. The automatic workpiece exchange device according to claim 1, wherein the workpiece stocker (6) has a bracket (30) extending horizontally from a lower portion of the enclosing frame portion (8) toward the machine tool (2) and a stocker-side locating block (31) fixed to a tip of the bracket (30), and the stocker-side locating block (31) is connected to a machine-side locating block (32) fixed to a lower portion of the machine tool (2), thereby making it possible to position the workpiece stocker (6) relative to the machine tool (2).

6. The work stocker (6) stores the plurality of works (W １ , W ３ The workpieces (W) are individually held by a plurality of work holders (14), and the workpieces (W) are held by the work holders (14). １ , W ３ ) is placed on the The work holder (14) has a flange portion (17) on the outer periphery of which is formed a circumferential groove (16) for gripping by the articulated robot arm (7), and is provided on one side of the flange portion (17) in the axial direction, and the work (W １ , W ３ 4. The automatic workpiece exchange device according to claim 1, further comprising a clamp portion (18) for clamping and fixing the workpiece (10) to the flange portion (17), and a tapered shank portion (19) provided on the other axial side of the flange portion (17).

7. 7. An automatic workpiece exchange device according to claim 6, wherein said tapered shank portion (19) is a hollow cylindrical HSK shank having a conical outer circumferential surface with a gradient of 1 / 10.

8. A method for machining a workpiece using the automatic workpiece exchange device according to claim 6, comprising the steps of: The machine tool (2) is a three-axis machining center having a main shaft (64) that rotates around a vertical axis and a horizontal table (62) that is movable relative to the main shaft (64), On the horizontal table (62), a first gripping device (61) to which the work holder (14) is removably attached with the axis of the tapered shank portion (19) horizontal, a rotary table (60) for rotating the first gripping device (61) about a horizontal axis to position it at an arbitrary angle, and a second gripping device (63) to which the work holder (14) is removably attached with the axis of the tapered shank portion (19) vertical are installed, The work (W １ The work holder (14) holding the work (W) is attached to one of the first gripping device (61) and the second gripping device (63) to grip the work (W). １ ) is processed, and then the workpiece (W ２ The work holder (14) holding the workpiece (W) is automatically transferred from one of the first gripping device (61) and the second gripping device (63) to the other gripping device (63) by the articulated robot arm (7), and the workpiece (W) is then automatically transferred from one of the first gripping device (61) and the second gripping device (63) to the other gripping device (63). ２ ) A method for machining a workpiece.

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