JP2016153163A - Workpiece conveyance device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a workpiece conveyance device capable of shortening waiting time accompanying workpiece conveyance.SOLUTION: Each of workpiece conveyance devices 2a to 2c includes a conveyance robot 20 for conveying a workpiece W along a conveyance path L1 from a workpiece carry-in position P1 to a workpiece carry-out position P3, and a controller 23 for controlling the conveyance robot 20. The conveyance path L1 is set so as to allow the conveyance robot 20 and the workpiece W to pass through a safe region R without interfering with an adjacent member. When the conveyance robot 20 has waiting time Tw with respect to at least one of the workpiece carry-in position P1 and the workpiece carry-out position P3, the controller 23 can execute path switching control for switching the conveyance path L1 from a shortest time path L2 set in a curve shape in the safe region R to a shortest distance path L3 set in a polygonal line shape in the safe region R.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a workpiece transfer device used to transfer a workpiece on a production line, for example.

  In a production line with a plurality of processes, the process with the longest cycle time becomes a bottleneck. That is, unless the process with the longest cycle time is completed, the workpiece cannot be transported downstream in the production line. For this reason, the cycle time of the other process inevitably and substantially follows the cycle time of the process having the longest cycle time.

  In this case, no matter how short the cycle time of any process other than the bottleneck process (specifically, the machine tool that executes the process) is short, the cycle time is reduced by incorporating the machine tool into the production line. It will be extended. That is, a waiting time is generated for waiting for the bottleneck process to be completed.

JP-A-10-309649

  In this regard, Patent Document 1 discloses a loader control device that lowers the speed and acceleration / deceleration of the loader when a waiting time for the loader to wait for the work is generated during the work. According to the loader control device of Patent Document 1, the loader carries in and out the workpiece with respect to the workpiece machining position of the machine tool.

  Here, when the machine tool is processing the first workpiece, even if the loader wants to load the second workpiece into the workpiece machining position, it cannot be loaded. For this reason, the loader waits for the machine tool to complete the machining of the first workpiece.

  Further, when the machine tool is machining the first workpiece, the loader cannot carry out the workpiece even if the loader wants to remove the first workpiece from the workpiece machining position. For this reason, the loader waits for the machine tool to complete the machining of the first workpiece.

  As described above, when the waiting time occurs, the operation rate of the loader decreases. In view of this point, the loader control device of Patent Document 1 reduces the loader speed and acceleration / deceleration when waiting time occurs. That is, the workpiece conveyance speed and conveyance acceleration / deceleration are reduced. According to the loader control device described in the document, the waiting time can be shortened. For this reason, the operating rate fall of a loader can be suppressed.

  However, although Patent Document 1 includes a description regarding a waiting time for “waiting for machining of a workpiece”, there is no description regarding a waiting time for “waiting for completion of the bottleneck process”.

  The workpiece transfer apparatus of the present invention has been completed in view of the above problems. An object of this invention is to provide the workpiece conveyance apparatus which can shorten the waiting time accompanying conveyance of a workpiece | work.

  (1) In order to solve the above-described problem, a workpiece transfer device according to the present invention includes a transfer robot that transfers a workpiece along a transfer path from a workpiece carry-in position to a workpiece carry-out position, a control device that controls the transfer robot, The transport path is set so as to pass through a safe area where the transport robot and the work can move without interfering with adjacent members, and the work transport position and the work When the transfer robot has a waiting time with respect to at least one of the unloading positions, the control device moves the transfer path from the shortest time path set in a curved shape in the safety area to the safety area. Route switching control for switching to the shortest distance route set in a polygonal line can be executed.

  Here, the “waiting time” with respect to the workpiece loading position refers to a stop time of the conveying robot due to the fact that the conveying robot cannot load the workpiece from the workpiece loading position. The “waiting time” for the workpiece unloading position refers to the stop time of the transfer robot due to the fact that the transfer robot cannot unload the workpiece to the workpiece unloading position. In addition, it does not specifically limit about the cause which cannot carry in and carry out a workpiece | work. Even if the cause is unknown, as a result, if the workpiece cannot be loaded or unloaded, the “waiting time” occurs.

  According to the workpiece transfer device of the present invention, the control device can execute path switching control. That is, the control device can switch the conveyance path from the shortest time path set in a curved line in the safety area to the shortest distance path set in a broken line in the safety area. For this reason, when the transfer robot has a waiting time for at least one of the workpiece carry-in position and the workpiece carry-out position, the transfer movement time of the transfer robot can be extended. Therefore, the waiting time can be shortened.

  (1-1) Preferably, in the configuration of the above (1), the transfer robot is disposed at the workpiece loading position, a workpiece machining position disposed downstream of the workpiece loading position, and a downstream side of the workpiece machining position. It is better to have a configuration in which workpieces are conveyed in the order of the workpiece unloading position.

  According to this configuration, the transfer robot transfers the workpiece from the workpiece loading position to the workpiece unloading position via the workpiece machining position. That is, the transfer robot transfers the workpiece before processing from the workpiece loading position to the workpiece processing position. Further, the transfer robot transfers the processed workpiece from the workpiece processing position to the workpiece unloading position.

  (2) Preferably, in the configuration of (1) above, the shortest distance route should have a longer transfer movement time and a shorter transfer movement distance than the shortest time route.

  According to this configuration, when the control device performs the path switching control, it is possible to reduce the waiting time associated with the conveyance of the workpiece.

  In addition to the path switching control, the control device can execute slow-down control that slows at least one of the speed and acceleration / deceleration of the transfer robot. When performing slow-down control, at least one of the speed and acceleration / deceleration of the transfer robot can be slowed down. For this reason, the power consumption of the transfer robot can be reduced. Further, for example, damage to the workpiece or the transfer robot due to an impact during transfer due to sudden acceleration or sudden deceleration can be reduced.

  When route switching control is performed, the workpiece transfer route can be switched from the shortest time route to the shortest distance route. For this reason, the power consumption of the transfer robot can be reduced. In addition, since the workpiece transfer distance is short, damage to the workpiece and the transfer robot during transfer can be reduced.

  (3) Preferably, in the configuration of the above (1) or (2), the control device sets the movement time of the shortest distance route as Tj, the movement time of the shortest time route as Ti, and the waiting time as Tw. When the condition of the expression “(Tj−Ti) <Tw” is satisfied, the shortest time path is preferably switched to the shortest distance path. If this formula does not hold, the cycle time becomes longer when the route is switched. According to this configuration, it is possible to prevent unnecessary path switching that leads to longer cycle time.

  (4) Preferably, in any one of the above configurations (1) to (3), any workpiece transfer device on a transfer line that transfers a plurality of workpiece transfer devices in series, and the waiting time It is better to have a configuration that occurs due to the cycle time of the work transfer device that becomes a bottleneck among the plurality of work transfer devices of the transfer line. A plurality of workpiece transfer devices are connected to the transfer line. When the cycle times of a plurality of workpiece transfer devices are different, the workpiece transfer device having the longest cycle time becomes a bottleneck. According to this structure, the waiting time resulting from the cycle time of the work transfer device that is the bottleneck can be shortened.

  ADVANTAGE OF THE INVENTION According to this invention, the workpiece conveyance apparatus which can shorten the waiting time accompanying conveyance of a workpiece | work can be provided.

It is a schematic diagram of the production line by which the workpiece conveyance apparatus of 1st embodiment is arrange | positioned. It is an enlarged view in the frame II of FIG. FIG. 3 is a perspective view of a portion corresponding to FIG. 2. It is a block diagram of a machining center and a workpiece conveyance apparatus. It is a front view of the workpiece carrying-in process 1st stage of a machining center and a workpiece conveyance apparatus. It is a front view of the process 2nd step of a machining center and a workpiece conveyance apparatus. It is a front view of the 3rd step of the same process of a machining center and a work conveyance device. It is a front view of the workpiece exchange process 1st stage of a machining center and a workpiece conveyance apparatus. It is a front view of the process 2nd step of a machining center and a workpiece conveyance apparatus. It is a front view of the 3rd step of the same process of a machining center and a work conveyance device. It is a front view of the fourth stage of the same process of the machining center and the workpiece transfer device. It is a front view of the workpiece carrying-out process first stage of a machining center and a workpiece conveyance apparatus. It is a front view of the process 2nd step of a machining center and a workpiece conveyance apparatus. It is a front view of the 3rd step of the same process of a machining center and a work conveyance device. It is a front view of the fourth stage of the same process of the machining center and the workpiece transfer device. It is the front view which emphasized the motion of the conveyance robot of a machining center and a workpiece conveyance apparatus. It is a flowchart (the 1) of the control method which the workpiece conveyance apparatus of this embodiment performs. It is a schematic diagram of the rotational speed-torque characteristic of the Z-axis motor of the workpiece transfer apparatus. It is a schematic diagram of the shortest time path | route of a workpiece | work. It is a schematic diagram of the shortest distance path | route of a workpiece | work. It is a schematic diagram of the determination method of the shortest distance path | route of a workpiece | work. It is a flowchart (the 2) of the control method which the workpiece conveyance apparatus of this embodiment performs. It is a schematic diagram of the production line by which the workpiece conveyance apparatus of 2nd embodiment is arrange | positioned. It is a schematic diagram of the production line by which the workpiece conveyance apparatus of 3rd embodiment is arrange | positioned.

  Hereinafter, embodiments of the workpiece transfer apparatus of the present invention will be described.

<< First Embodiment >>
<Production line>
First, the structure of the production line in which the workpiece conveyance apparatus of this embodiment is arrange | positioned is demonstrated. In FIG. 1, the schematic diagram of the production line by which the workpiece conveyance apparatus of this embodiment is arrange | positioned is shown. As shown in FIG. 1, the production line 9 includes three workpiece transfer devices 2a to 2c, three machining centers 3a to 3c, two inter-process relay devices 4b and 4c, and an unprocessed workpiece supply device 4a. And a finished work stocker device 4d.

  From the left side (upstream in the transfer direction) to the right side (downstream in the transfer direction), these devices are the unprocessed workpiece supply device 4a → the first machining center 3a and the workpiece transfer device 2a → the first inter-process relay device 4b. → Second machining center 3b and workpiece transfer device 2b → second inter-process relay device 4c → third machining center 3c and workpiece transfer device 2c → work completed workpiece stocker device 4d.

  The workpiece W is conveyed on the production line 9 by the three workpiece conveyance devices 2a to 2c. That is, the production line 9 includes the three workpiece transfer apparatuses 2a to 2c connected to form a transfer line 8. The workpiece W to be transported is processed in stages by the three machining centers 3a to 3c.

  Among the three machining centers 3a to 3c (three workpiece transfer apparatuses 2a to 2c), the machining center 3c (work transfer apparatus 2c) has the longest cycle time alone. For this reason, the cycle times of the three machining centers 3a to 3c (three workpiece transfer apparatuses 2a to 2c) incorporated in the production line 9 (transfer line 8) are all the cycle times of the machining center 3c (work transfer apparatus 2c). become. In other words, the cycle time of the machining centers 3a and 3b (work transfer devices 2a and 2b) is incorporated into the production line 9 (transfer line 8), resulting in a long time.

<Machining center>
Next, the configuration of the machining centers 3a to 3c will be described. The configuration of the machining centers 3a to 3c is the same. Here, the configuration of the machining center 3b will be described on behalf of the machining centers 3a to 3c.

  FIG. 2 shows an enlarged view in the frame II of FIG. FIG. 3 is a perspective view of a portion corresponding to FIG. FIG. 4 shows a block diagram of the machining center and the workpiece transfer device. As shown in FIGS. 2 to 4, the machining center 3 b includes a bed 30, a head stock 31, a tool shaft side slide 32, and a control device 23. The control device 23 is also used as the machining center 3b and the work transfer device 2b. The control device 23 will be described later.

(Bed 30 and headstock 31)
The bed 30 is arranged on the floor of the factory. The headstock 31 is disposed on the left portion of the upper surface of the bed 30. The head stock 31 includes an X-axis (front-rear direction) lower slide 310, an X-axis slide 311, a main body 312, a main shaft-side chuck 313, an X-axis motor 314, and a rotation motor 315.

  The X-axis lower slide 310 is disposed on the upper surface of the bed 30. The X-axis lower slide 310 extends in the front-rear direction. The X-axis slide 311 is attached to the X-axis lower slide 310 so as to be movable in the front-rear direction. The X-axis motor 314 drives the X-axis slide 311. The main body 312 is attached to the X-axis slide 311. The spindle side chuck 313 is a so-called three-claw chuck. The configuration of the three-jaw chuck is disclosed in Japanese Patent Application Laid-Open No. 11-300568 and Japanese Utility Model Publication No. 4-32197. The main shaft side chuck 313 is fixed to a work holding shaft (not shown). The work holding shaft extends in the left-right direction (Z-axis direction). The rotation motor 315 rotates the workpiece holding shaft around the axis. The spindle side chuck 313 can grip and release the cylindrical workpiece W by three claw members (not shown). When the workpiece W and the spindle side chuck 313 rotate around the axis together with the workpiece holding shaft, the processing angle (for example, 30 °, 45 °, etc.) of the workpiece W is indexed.

(Tool axis side slide 32)
The tool shaft side slide 32 is disposed on the right portion of the upper surface of the bed 30. The tool axis side slide 32 includes a Z axis lower slide 320, a Z axis slide 321, a column 322, a Y axis (vertical direction) lower slide 323, a Y axis slide 324, a Y axis motor 325, and a Z axis motor. 326 and a tool shaft 327.

  The Z-axis lower slide 320 is disposed on the upper surface of the bed 30. The Z-axis lower slide 320 extends in the left-right direction. The Z-axis slide 321 is attached to the Z-axis lower slide 320 so as to be movable in the left-right direction. The Z axis motor 326 drives the Z axis slide 321. The column 322 is attached to the Z-axis slide 321. The Y-axis lower slide 323 is disposed on the left surface of the column 322. The Y-axis lower slide 323 extends in the up-down direction. The Y-axis slide 324 is attached to the Y-axis lower slide 323 so as to be movable in the vertical direction. The Y axis motor 325 drives the Y axis slide 324. A tool T is attached to the tool shaft 327 so as to be replaceable.

<Work transfer device>
Next, the structure of the workpiece conveyance apparatuses 2a-2c is demonstrated. The structure of the workpiece conveyance apparatuses 2a-2c is the same. Here, the structure of the workpiece transfer device 2b will be described on behalf of the workpiece transfer devices 2a to 2c.

  The workpiece transfer device 2b is a so-called gantry loader. The workpiece transfer device 2b includes a transfer robot 20, a robot traveling platform 21, a pair of support posts 22, a control device 23, a robot arm vertical axis motor 24, a robot traveling motor 25, and a robot chuck turning motor 26. And an input device 27.

(A pair of struts 22 and a robot carriage 21)
Of the pair of left and right columns 22, the left column 22 is fixed to the left surface of the bed 30. The left column 22 extends in the vertical direction. The right column 22 is fixed to the right surface of the bed 30. The right column 22 extends in the vertical direction. The robot carriage 21 is installed between the upper ends of a pair of left and right columns 22. The robot carriage 21 extends in the left-right direction.

(Transport robot 20, robot arm vertical axis motor 24, robot travel motor 25, robot chuck rotation motor 26)
The transfer robot 20 includes a travel axis slide 200, a Y-axis telescopic arm 201, a robot arm 202, a pair of robot chucks 203, and a main body 204. The travel axis slide 200 is attached to the robot platform 21 so as to be movable in the left-right direction. The robot travel motor 25 drives the travel axis slide 200. The main body 204 is fixed to the traveling shaft slide 200. The Y-axis telescopic arm 201 can be expanded and contracted downward with respect to the main body 204. The robot arm vertical axis motor 24 drives the Y-axis telescopic arm 201. The robot arm 202 protrudes backward from the lower end of the Y-axis telescopic arm 201. The robot arm 202 can rotate around an axis. The robot for turning the chuck chuck 26 drives the robot arm 202. The pair of robot chucks 203 are attached to the rear end of the robot arm 202. Both of the pair of robot chucks 203 are so-called three-jaw chucks.

(Control device 23, input device 27)
The control device 23 includes a computer 230 and a plurality of drive circuits. The computer 230 includes an input / output interface 230a, a calculation unit 230b, and a storage unit 230c. The input / output interface 230a is connected to the robot arm vertical axis motor 24 of the workpiece transfer device 2b, the robot traveling motor 25, the robot chuck turning motor 26, the X-axis motor 314 of the headstock 31, the rotation motor 315, via the drive circuit. The Y axis motor 325 and the Z axis motor 326 of the tool axis side slide 32 are connected. The input / output interface 230a is connected to the input device 27 of the work transfer device 2b.

<Unprocessed Work Supply Device 4a, Finished Work Stocker Device 4d>
Next, configurations of the unmachined workpiece supply device 4a and the machining completed workpiece stocker device 4d will be described. The raw workpiece supply device 4a is disposed on the left side of the machining center 3a (see FIG. 1). A plurality of unprocessed workpieces W are stocked in the unmachined workpiece supply device 4a.

  That is, the raw workpiece supply device 4a includes a table (not shown). On the upper surface of the table, ten stockers (not shown) connected in an annular shape are arranged. A plurality of workpieces W before processing are stacked on the stocker. As the ten stockers rotate by a predetermined length, the stocker (that is, the workpiece W) is sequentially sent to the loading position. The work W at the carry-in position is carried into the machining center 3a by the work transfer device 2a.

  The processed workpiece stocker device 4d has the same configuration as the unprocessed workpiece supply device 4a. In other words, the processed work stocker device 4d includes a table (not shown). On the upper surface of the table, ten stockers (not shown) connected in an annular shape are arranged. As the ten stockers rotate by a predetermined length, the stockers are sequentially sent to the carry-out position. The workpiece W is unloaded by the workpiece transfer device 2c to the unloading position stocker.

<Inter-process relay device 4b, 4c>
Next, the configuration of the inter-process relay devices 4b and 4c will be described. The configuration of the inter-process relay devices 4b and 4c is the same. Here, the configuration of the inter-process relay device 4b will be described on behalf of the inter-process relay devices 4b and 4c.

  The inter-process relay device 4b is disposed between the machining center 3a (see FIG. 1) and the machining center 3b. The inter-process relay device 4 b includes a table 40, a shift device 44, and a tray 45.

  The table 40 is arranged on the floor of the factory. The shift device 44 is disposed on the upper surface of the table 40. The tray 45 is disposed on the upper surface of the shift device 44. The shift device 44 can reciprocate the tray 45 in the left-right direction. The workpiece W is placed on the tray 45.

<Work transfer method>
Next, a work conveyance method will be described. The movement of the workpiece transfer apparatuses 2a to 2c in the workpiece transfer method is the same. Here, the movement of the workpiece transfer device 2b will be described on behalf of the workpiece transfer devices 2a to 2c. The work conveyance method includes a work carry-in process, a work exchange process, and a work carry-out process. In the work unloading process, the work machining process is executed in parallel.

(Work loading process)
In this process, the workpiece W before processing is carried into the machining center 3b from the inter-process relay device 4b. FIG. 5 shows a front view of the first stage of the workpiece carry-in process of the machining center and the workpiece transfer device. FIG. 6 shows a front view of the second stage of the machining center and the workpiece transfer device. FIG. 7 shows a front view of the third stage of the machining center and the workpiece transfer device. 5 to 7, the processed workpiece W is hatched.

  In this step, first, the control device 23 shown in FIG. 4 drives the robot travel motor 25 of the work transfer device 2b. That is, as shown in FIG. 5, the robot chuck 203 is disposed directly above the tray 45 of the inter-process relay device 4b. Next, the control device 23 shown in FIG. 4 drives the robot arm vertical axis motor 24 of the workpiece transfer device 2b. That is, as shown in FIG. 5, the Y-axis telescopic arm 201 is extended downward from the main body 204. Subsequently, the control device 23 illustrated in FIG. 4 grips the workpiece W at the workpiece loading position P <b> 1 by the robot chuck 203. Then, the control device 23 shown in FIG. 4 drives the robot arm vertical axis motor 24 of the workpiece transfer device 2b. That is, as shown in FIGS. 5 and 6, the Y-axis telescopic arm 201 is contracted upward. Subsequently, the control device 23 shown in FIG. 4 drives the robot traveling motor 25 of the workpiece transfer device 2b. That is, as shown in FIGS. 6 and 7, the transfer robot 20 is moved to the right side, and the robot chuck 203 is placed directly above the right side space (workpiece processing position P <b> 2 described later) of the spindle side chuck 313 of the headstock 31. Deploy. Then, the control device 23 shown in FIG. 4 drives the robot arm vertical axis motor 24 of the workpiece transfer device 2b. That is, as shown in FIG. 7, the Y-axis telescopic arm 201 is extended downward from the main body 204.

(Work changing process)
In this step, the processed workpiece W is removed from the spindle chuck 313 of the machining center 3b. Further, the workpiece W before processing is attached to the spindle chuck 313. FIG. 8 shows a front view of the first stage of the workpiece replacement process of the machining center and the workpiece transfer device. FIG. 9 shows a front view of the second stage of the machining center and the workpiece transfer device. FIG. 10 shows a front view of the third stage of the machining center and the workpiece transfer device. FIG. 11 is a front view of the fourth stage of the same process of the machining center and the workpiece transfer device. 8 to 11, the processed workpiece W is hatched.

  In this step, first, the control device 23 shown in FIG. 4 drives the robot chuck turning motor 26 of the workpiece transfer device 2b. That is, as shown in FIGS. 8 and 9, the robot arm 202 is rotated 90 ° at the workpiece machining position P2, and the empty robot chuck 203 and the workpiece W on the spindle side chuck 313 are moved in the left-right direction. Make them face each other. Next, the control device 23 shown in FIG. 4 removes the processed workpiece W from the spindle side chuck 313 shown in FIG. 9 and attaches the workpiece W to the empty robot chuck 203. That is, as shown in FIGS. 9 and 10, the processed workpiece W is transferred from the spindle chuck 313 to the robot chuck 203. Subsequently, the control device 23 shown in FIG. 4 drives the robot chuck turning motor 26 of the workpiece transfer device 2b. That is, as shown in FIGS. 10 and 11, the robot arm 202 is rotated 180 ° at the workpiece machining position P2, and the workpiece W before machining of the robot chuck 203 and the empty spindle-side chuck 313 are moved in the left-right direction. Make them face each other. Then, the control device 23 shown in FIG. 4 removes the workpiece W before processing from the robot chuck 203 shown in FIG. 11 and attaches the workpiece W to the empty spindle-side chuck 313. That is, as shown in FIG. 11, the workpiece W before processing is transferred from the robot chuck 203 to the spindle chuck 313.

(Work unloading process)
In this process, the processed workpiece W is carried out from the machining center 3b to the inter-process relay device 4c. FIG. 12 shows a front view of the first stage of the workpiece unloading process of the machining center and the workpiece transfer device. FIG. 13 shows a front view of the second stage of the same process of the machining center and the workpiece transfer device. FIG. 14 shows a front view of the third stage of the machining center and the workpiece transfer device. FIG. 15 shows a front view of the fourth stage of the process of the machining center and the work transfer device. 12 to 15, the processed workpiece W is hatched.

  In this step, first, the control device 23 shown in FIG. 4 drives the robot chuck turning motor 26 of the workpiece transfer device 2b. That is, as shown in FIGS. 11 and 12, the robot arm 202 is rotated 90 ° so that the processed workpiece W faces downward at the workpiece processing position P2. Next, the control device 23 shown in FIG. 4 drives the robot arm vertical axis motor 24 of the workpiece transfer device 2b. That is, as shown in FIGS. 12 and 13, the Y-axis telescopic arm 201 is contracted upward. Subsequently, the control device 23 shown in FIG. 4 drives the robot traveling motor 25 of the workpiece transfer device 2b. That is, as shown in FIGS. 13 and 14, the transfer robot 20 is moved to the right side, and the processed workpiece W is disposed directly above the tray 45 of the inter-process relay device 4 c. Then, the control device 23 shown in FIG. 4 drives the robot arm vertical axis motor 24 of the workpiece transfer device 2b. That is, as shown in FIGS. 14 and 15, the Y-axis telescopic arm 201 is extended downward from the main body 204. Then, the robot chuck 203 is released, and the workpiece W is placed at the workpiece carry-out position P3. After placing the workpiece W, the transfer robot 20 again takes the workpiece W before processing to the workpiece loading position P1 of the inter-process relay device 4b as shown in FIG.

  FIG. 16 shows a front view of the machining center and the workpiece transfer device, emphasizing the movement of the transfer robot. In FIG. 16, the machined workpiece W is hatched. As shown by a thick line in FIG. 16, in the workpiece transfer method (work loading step, workpiece replacement step, workpiece unloading step), the pair of robot chucks 203 is configured to transfer a workpiece W transfer path L1 (specific transfer path will be described later). ). The workpiece transfer device 2b repeatedly executes the above series of steps.

  As indicated by a one-dot chain line in FIG. 16, a safety region R is secured around the conveyance path L1 of the workpiece W (= the movement path of the robot chuck 203). The safety region R is a region where the pair of robot chucks 203 and the workpiece W can move without interfering with adjacent members. The transport path L1 is set so as to pass through the safety area R.

(Work machining process)
The workpiece machining process is executed in parallel with the workpiece unloading process. That is, a predetermined process is performed on the workpiece W attached to the spindle side chuck 313. First, the control device 23 shown in FIG. 4 drives the X-axis motor 314 of the head stock 31. That is, as shown in FIG. 3, the X-axis slide 311 and the main body 312 are moved backward with respect to the X-axis lower slide 310. And the workpiece | work W of the spindle side chuck | zipper 313 and the tool T of the tool axis | shaft 327 are made to oppose in the left-right direction. Next, the control device 23 shown in FIG. 4 drives the rotary motor 315 of the head stock 31. That is, the workpiece W shown in FIG. 3 is rotated around the axis, and the workpiece W is fixed at a predetermined processing angle. Then, the control device 23 shown in FIG. 4 appropriately drives the Y-axis motor 325 and the Z-axis motor 326 of the tool shaft side slide 32. That is, as shown in FIGS. 13 to 15, the workpiece W is machined with the tool T.

<Control Method of Work Conveying Device (Part 1)>
The workpiece transfer apparatus 2 according to the present embodiment executes a control method described below in parallel with the workpiece transfer method shown in FIGS. The control method is common to the workpiece transfer apparatuses 2a to 2c. Here, as a representative of the workpiece transfer apparatuses 2a to 2c, a method for controlling the workpiece transfer apparatus 2b will be described. FIG. 17 shows a flowchart (No. 1) of the control method executed by the work transfer device of the present embodiment.

(Step 1 (S1))
In step 1, the control device 23 shown in FIG. 4 determines whether or not the steady operation has been determined.

(Step 6 (S6))
If the steady operation has not been determined in step 1, the process proceeds to step 6. In step 6, the control device 23 shown in FIG. That is, the steady operation head code is stored in the storage unit 230c of the control device 23 in advance. Specifically, the operation in the first stage of the workpiece loading process shown in FIG. 5 (the operation in which the robot chuck 203 picks up the workpiece W before processing until the workpiece loading position P1) is stored as a steady operation head code. Yes. The storage unit 230c executes an operation pattern (specifically, the work transfer method shown in FIGS. 5 to 15 is executed after the steady operation head code is executed and until the steady operation head code is executed again. The operation pattern until the operation in the first stage of the workpiece loading process shown in FIG. 5 is executed is stored. When the operation pattern is continuously executed a prescribed number of times (for example, 3 times), the calculation unit 230b determines the operation pattern as a steady operation. The storage unit 230c stores the steady operation. In this way, the control device 23 determines a steady operation.

(Step 2 (S2))
If the steady operation has been determined in step 1, the process proceeds to step 2. In step 2, the control device 23 shown in FIG. 4 determines whether or not the cycle time required for steady operation has been measured.

  Further, the control device 23 determines whether or not the conveyance movement time within the cycle time has been measured. Specifically, the transfer movement time is the time required for the work carry-in process (FIGS. 5 to 7) and the work carry-out process (FIGS. 12 to 15).

  Further, the control device 23 determines whether or not the pre- and post-process waiting times have been measured within the cycle time. The waiting time before and after the process is included in the concept of “waiting time” of the present invention. The pre-process waiting time is a time during which the workpiece transfer device 2b waits for the workpiece W to be carried into the inter-process relay device 4b from the machining center 3a shown in FIG. In the waiting time for the previous process, the transfer robot 20 is stopped. The post-process waiting time is a time during which the workpiece transfer device 2b waits for the workpiece W to be unloaded from the inter-process relay device 4c shown in FIG. 1 to the machining center 3c. In the post-process waiting time, the transfer robot 20 is stopped. The waiting time before and after the process means the longer one of the waiting time for the previous process and the waiting time for the subsequent process.

(Step 7 (S7))
If at least one of the cycle time, the transfer movement time, and the waiting time before and after the process has not been measured in step 2, the process proceeds to step 7. In step 7, the control device 23 shown in FIG. 4 measures an unmeasured parameter among the cycle time, the transfer movement time, and the waiting time before and after the process. The storage unit 230c stores the measured data.

(Step 3 (S3))
If the cycle time, the transfer movement time, and the waiting time before and after the process are all measured in step 2, the process proceeds to step 3. In step 3, the operator instructs the control device 23 to execute slow-down control or route switching control via the input device 27 shown in FIG. 4.

(Step 4 (S4))
If slowdown control is selected in step 3, the process proceeds to step 4. In step 4, the control device 23 shown in FIG. 4 calculates speed and acceleration / deceleration correction values. Specifically, the correction value X is calculated by the following equation (1) from the transport movement time Ti and the preceding and following process waiting time Tw stored in the storage unit 230c (see Step 7).
X = {Ti / (Ti + Tw)} × 100 (1)
Then, the speed and acceleration / deceleration are corrected by multiplying the correction value X by the speed and acceleration / deceleration of the transfer robot 20 shown in FIG. Specifically, the output pattern instructed by the control device 23 shown in FIG. 4 to the robot arm vertical axis motor 24 and the robot travel motor 25 of the workpiece transfer device 2b is changed so that a predetermined speed and acceleration / deceleration can be achieved. To do.

  In step 4, the control device 23 shown in FIG. 4 limits the output torque of the robot arm vertical axis motor 24 and the robot travel motor 25 of the workpiece transfer device 2 b. In FIG. 18, the schematic diagram of the rotational speed-torque characteristic of the Z-axis motor of the workpiece conveyance apparatus of this embodiment is shown. The control device 23 issues a torque limit instruction to the robot travel motor 25 so that the instantaneous maximum torque is cut and only the maximum torque within the rated torque can be output. The control device 23 also issues a similar torque limit instruction to the robot arm vertical axis motor 24.

(Step 5 (S5))
In step 5, the speed of the transfer robot 20, the acceleration / deceleration, the torque of the robot running motor 25, and the torque of the robot arm vertical axis motor 24 changed in step 4 are used to perform the steady operation, that is, the above-described FIGS. The workpiece transfer method is repeatedly executed.

  When the slow-down control is executed, the operation of the transfer robot 20 becomes slow. For this reason, the conveyance movement time Ti becomes long. On the other hand, the waiting time Tw before and after the process is shortened.

(Step 8 (S8))
If route switching control is selected in step 3, the process proceeds to step 8. In step 8, the control device 23 shown in FIG. 4 calculates the shortest distance route and the shortest distance route movement time.

  FIG. 19 is a schematic diagram of the shortest time path of the workpiece (robot chuck). FIG. 20 shows a schematic diagram of the shortest distance path of the workpiece (robot chuck). 19 and 20 correspond to FIG.

  As shown by dotted lines in FIGS. 19 and 20, in FIG. 16, the conveyance path L <b> 1 has a downward E-shape. However, as indicated by the solid line in FIG. 19, in reality, the transfer path of the workpiece W (= the movement path of the robot chuck 203) is set to the shortest time path L2. That is, the shortest time path L2 is set in a curved shape so that the transport movement time Ti is the shortest. On the other hand, as indicated by a solid line in FIG. 20, the shortest distance path L3 is set in a polygonal line shape (a shape in which straight lines are connected) so that the transport movement distance is the shortest.

  In this step, first, the computing unit 230b shown in FIG. 4 determines the shortest distance route L3 shown in FIG. FIG. 21 shows a schematic diagram of a method for determining the shortest distance path of a workpiece (robot chuck). As shown by the alternate long and short dash line in FIG. 21, first, the calculation unit 230b divides the safety region R into a plurality of quadrangles D1 to D8. Next, arbitrary vertices Px of the plurality of quadrangles D1 to D8 are connected so as to pass through the workpiece loading position P1, the workpiece machining position P2, and the workpiece unloading position P3 in this order. There are many patterns connecting the vertices Px. The calculation unit 230b determines the shortest distance path L3 illustrated in FIG. 20 from among a large number of patterns. The calculation unit 230b calculates the time required for the movement of the shortest distance route L3, that is, the shortest distance route movement time. The storage unit 230c stores the shortest distance route L3 and the shortest distance route movement time Tj.

(Step 9 (S9))
In step 9, the control device 23 shown in FIG. 4 determines whether or not the shortest time path L2 shown in FIG. 19 can be switched to the shortest distance path L3 shown in FIG. Specifically, whether or not the following expression (2) is satisfied in the shortest distance route moving time Tj, the current (before switching) transfer moving time (that is, the shortest time route moving time) Ti, and the preceding and following process waiting time Tw. Is determined.
Tj−Ti <Tw (2)
If the equation (2) is not established, the cycle time becomes long when the route is switched. Therefore, the process proceeds to step 5 without switching the route. That is, the steady operation is repeatedly executed.

(Step 10 (S10))
When the formula (2) is established in step 9, the process proceeds to step 10. In step 10, the control device 23 shown in FIG. 4 switches the shortest time path L2 shown in FIG. 19 to the shortest distance path L3 shown in FIG.

  Thereafter, the process proceeds to step 5. In step 5, using the shortest distance path L3 switched in step 10, the steady operation, that is, the workpiece transfer method shown in FIGS. 5 to 15 is repeatedly executed.

  When the path switching control is executed, the operation of the transfer robot 20 becomes slow. For this reason, the conveyance movement time Ti becomes long. On the other hand, the waiting time Tw before and after the process is shortened.

<Control Method of Work Conveying Device (Part 2)>
The control described below is executed during steady operation. Specifically, it is executed in step 5 shown in FIG. That is, when the steady operation is repeatedly executed, the non-steady operation may intervene (for example, the attachment state of the work W with respect to the robot chuck 203 or the spindle chuck 313 is bad and the attachment operation is performed again). When the unsteady operation is executed, the production of the workpiece W is delayed correspondingly. In order to recover the delay, it is necessary to temporarily stop the slow-down control and the path switching control to shorten the work transfer time. In such a case, the control device 23 shown in FIG. 4 executes the control described below.

  The control method is common to the workpiece transfer apparatuses 2a to 2c. Here, as a representative of the workpiece transfer apparatuses 2a to 2c, a method for controlling the workpiece transfer apparatus 2b will be described. FIG. 22 shows a flowchart (No. 2) of the control method executed by the work transfer device of this embodiment.

(Step 20 (S20))
In step 20, the control device 23 shown in FIG. 4 is executing the slow-down control or the path switching control.

(Step 21 (S21))
In step 20, the control device 23 shown in FIG. 4 determines whether or not the code (work) in the steady operation is being executed. Specifically, it is determined whether or not the work shown in FIGS.

(Step 22 (S22))
If there is no operation stop command from the control device 23 shown in FIG. 4 (or from the operator via the input device 27 shown in FIG. 4), the process returns to step 21. On the other hand, if there is an operation stop command from the control device 23 shown in FIG. 4 (or from the operator via the input device 27 shown in FIG. 4), the process proceeds to step 25.

(Step 23 (S23))
If the code in the steady operation is not executed in step 21 (that is, if the unsteady operation is executed), the process proceeds to step 23. In step 23, the control device 23 shown in FIG. 4 resets the slow-down control or the path switching control.

  That is, when the slow-down control is reset, the correction value X relating to the speed of the transfer robot 20 and the acceleration / deceleration applied in step 4 of FIG. 17 and the output torque limit for the robot travel motor 25 and the robot arm vertical axis motor 24 are applied. Is released. When resetting the route switching control, the shortest distance route L3 shown in FIG. 20 applied in step 10 of FIG. 17 is switched to the shortest time route L2 shown in FIG.

  When step 23 is executed, the operation of the transfer robot 20 becomes quicker. For this reason, the conveyance movement time Ti is shortened. Therefore, the production delay of the workpiece W due to the unsteady operation can be recovered.

(Step 24 (S24))
In step 24, the calculation unit 230b shown in FIG. 4 compares the number of executions k of the code outside the steady operation (work that is not work in the steady operation = unsteady operation) with the threshold value N2. That is, the storage unit 230c stores in advance a threshold value N2 of the number of times of execution of the non-steady operation code. In addition, the storage unit 230c stores the number of executions k of the non-steady operation code.

  As a result of the comparison, if the number of executions of the code outside the steady operation k ≦ threshold N2, the control is terminated without resetting the steady operation. That is, the control shown in FIG. 17 is executed.

(Step 25 (S25))
If there is an operation stop command in step 22 and if the number of executions k of the non-steady operation code is greater than the threshold value N2 in step 24, the process proceeds to step 25. In step 25, the control device 23 shown in FIG. 4 resets the steady operation. Specifically, the steady operation (see Step 6 in FIG. 17) stored in the storage unit 230c is deleted from the storage unit 230c. Thereafter, this control is terminated. That is, the control shown in FIG. 17 is executed.

<Effect>
Next, the effect of the workpiece conveyance apparatus of this embodiment is demonstrated. According to the workpiece transfer apparatuses 2a to 2c of the present embodiment, the transfer robot 20 has the front and rear process waiting time Tw shown in FIG. 17 with respect to at least one of the workpiece carry-in position P1 and the workpiece carry-out position P3 shown in FIG. In this case, the transfer movement time Ti of the transfer robot 20 can be increased. For this reason, the said waiting time Tw before and behind the process can be shortened.

  Further, as shown in FIG. 17, the control device 23 shown in FIG. 4 executes slow-down control (step 4) or path switching control (steps 8 to 10) in order to increase the transport movement time Ti. For this reason, the pre- and post-process waiting time Tw accompanying conveyance of the workpiece | work W can be shortened.

  When performing slow-down control, the speed and acceleration / deceleration of the transfer robot 20 shown in FIG. 2 can be reduced. For this reason, the power consumption of the transfer robot 20 can be reduced. Further, for example, damage to the workpiece W or the transfer robot 20 due to an impact during transfer due to sudden acceleration or sudden deceleration can be reduced. In addition, the service life of parts constituting the transfer robot 20 is extended.

  Further, when the slow down control is performed, the output torque of the robot arm vertical axis motor 24 and the robot traveling motor 25 shown in FIG. 4 can be limited. For this reason, even if it is a case where the workpiece | work W and the conveyance robot 20 interfere and collide with an adjacent member etc. during conveyance, the damage which the workpiece | work W, the conveyance robot 20, and an adjacent member receive can be reduced.

  On the other hand, when the path switching control is performed, the transfer path of the workpiece W (the movement path of the robot chuck 203) can be switched from the shortest time path L2 shown in FIG. 19 to the shortest distance path L3 shown in FIG. For this reason, the power consumption of the transfer robot 20 can be reduced. Moreover, since the conveyance distance of the workpiece | work W is short, the damage which the workpiece | work W and the conveyance robot 20 receive during conveyance can be reduced. In addition, the service life of parts constituting the transfer robot 20 is extended.

  Moreover, according to the workpiece transfer apparatuses 2a to 2c of the present embodiment, the cycle time of the workpiece transfer apparatus 2c serving as a bottleneck among the three workpiece transfer apparatuses 2a to 2c constituting the transfer line 8 shown in FIG. The waiting time Tw before and after the process of the workpiece transfer apparatuses 2a and 2b due to Ts can be shortened.

<< Second Embodiment >>
The difference between the present embodiment and the first embodiment is only the line configuration of the production line (conveyance line). Here, only differences will be described.

  In FIG. 23, the schematic diagram of the production line by which the workpiece conveyance apparatus of this embodiment is arrange | positioned is shown. In addition, about the site | part corresponding to FIG. 1, it shows with the same code | symbol. As shown in FIG. 23, the production line 9 includes five workpiece transfer devices 2a to 2e, five machining centers 3a to 3e, four inter-process relay devices 4b, 4c, 4e, and 4f, and unprocessed A workpiece supply device 4a and a processed workpiece stocker device 4d are provided.

  For example, the cycle time of the workpiece transfer device 2a (ie, the machining center 3a) alone is 23 seconds, the cycle time of the workpiece transfer device 2b (ie, the machining center 3b) alone is 21 seconds, and the cycle time of the workpiece transfer device 2c (ie, the machining center 3c) alone is Assume that the cycle time of the workpiece transfer device 2d (that is, the machining center 3d) alone is 22 seconds and the cycle time of the workpiece transfer device 2e (that is, the machining center 3e) alone is 24 seconds. In this case, the work transfer device 2c becomes a bottleneck.

  As shown in FIG. 23, when the workpiece transfer devices 2a to 2e are connected and production is started, the cycle time (= 25 seconds) of the workpiece transfer device 2c gradually increases to the other workpiece transfer devices 2a, 2b, 2d, This will prolong the cycle time of 2e. For this reason, finally, the cycle time of all the workpiece transfer apparatuses 2a to 2e becomes 25 seconds.

  Each of the five workpiece transfer devices 2a to 2e includes control devices 23a to 23e. As shown by the dotted double-ended arrows in FIG. 23, any adjacent workpiece transfer devices 2a to 2e (that is, the control devices 23a to 23e) monitor the cycle time with each other.

  Here, each of the five workpiece transfer devices 2a to 2e does not know that the workpiece transfer device 2c is a bottleneck. However, each control apparatus 23a-23e can recognize the conveyance condition of the adjacent workpiece conveyance apparatuses 2a-2e. For example, the inter-process relay devices 4b, 4c, 4e, and 4f include a work presence / absence switch. From the ON / OFF state of the work presence / absence switch (= work is present) -OFF (= work is not present), each of the control devices 23a to 23e can determine the presence or absence of work in the inter-process relay devices 4b, 4c, 4e, and 4f. . In other words, when there is no workpiece in the upstream inter-process relay devices 4b, 4c, 4e, and 4f as viewed from any workpiece transfer devices 2a to 2e (when the workpiece presence / absence switch is off), a waiting time for the previous process occurs. To do. On the other hand, when there is a workpiece in the downstream inter-process relay devices 4b, 4c, 4e, and 4f as viewed from any workpiece transfer device 2a to 2e (when the workpiece presence / absence switch is on), a waiting time for the subsequent process occurs. To do. Thus, each control apparatus 23a-23e can recognize the conveyance condition of the adjacent workpiece conveyance apparatuses 2a-2e.

  After the cycle time of all the workpiece transfer apparatuses 2a to 2e has reached 25 seconds, each of the control apparatuses 23a to 23e independently executes the control method of FIGS. 17 and 22 of the first embodiment.

  The workpiece conveyance apparatus of this embodiment has the same effect as the workpiece conveyance apparatus of 1st embodiment. Like this embodiment, each control apparatus 23a-23e of the five workpiece conveyance apparatuses 2a-2e may each independently perform the control method of FIG. 17, FIG.

<< Third embodiment >>
The difference between the present embodiment and the second embodiment is that the host control device executes the control method of FIGS. 17 and 22 of the first embodiment. Here, only differences will be described.

  In FIG. 24, the schematic diagram of the production line by which the workpiece conveyance apparatus of this embodiment is arrange | positioned is shown. In addition, about the site | part corresponding to FIG. 23, it shows with the same code | symbol. As shown in FIG. 24, the transport line 8 includes a host control device 80. The host controller 80 is included in the concept of the “controller” of the present invention.

  The five workpiece transfer devices 2a to 2e and the host control device 80 are connected by a LAN (Local Area Network). The five workpiece transfer devices 2a to 2e sequentially transmit their cycle times to the host control device 80. When the five workpiece transfer devices 2a to 2e are prepared (that is, the cycle time of the five workpiece transfer devices 2a to 2e becomes 25 seconds for the cycle time of the workpiece transfer device 2c that is the bottleneck). Then, the cycle time (= 25 seconds) is transmitted to each workpiece transfer device 2a to 2e.

  After the cycle time of all the workpiece transfer apparatuses 2a to 2e reaches 25 seconds, the host control apparatus 80 executes the control method of FIGS. 17 and 22 of the first embodiment.

  The workpiece conveyance apparatus of this embodiment has the same effect as the workpiece conveyance apparatus of 1st embodiment. As in the present embodiment, the host control device 80 may generally execute the control methods of FIGS. 17 and 22.

  As shown in FIG. 23, in the case of the second embodiment, the workpiece transfer devices 2a to 2e have control devices 23a to 23e, respectively. Each of these control devices 23a to 23e can only monitor the cycle time (pre- and post-process waiting time) of the workpiece transfer devices 2a to 2e in the previous process or the subsequent process. For this reason, it was not possible to unify the cycle times of the workpiece transfer apparatuses 2a to 2e at the same time as the cycle time of the workpiece transfer apparatus 2c that is a bottleneck.

  On the other hand, as shown in FIG. 24, according to the present embodiment, what cycle time is currently being operated from each of the workpiece transfer apparatuses 2a to 2e connected to the LAN to the host control apparatus 80. To be reported instantly. For this reason, the high-order control apparatus 80 can monitor the cycle time of all the workpiece conveyance apparatuses 2a-2e. Therefore, the host control device 80 can easily determine which work transfer device 2a to 2e is a bottleneck. Therefore, the host controller 80 can instruct the work transfer devices 2a to 2e at a time so as to move at the cycle time of the work transfer device 2c, which is a bottleneck. That is, the cycle time of each workpiece transfer device 2a to 2e can be unified to the cycle time of the workpiece transfer device 2c that is a bottleneck at a time.

  It should be noted that the embodiment of the host control device 80 may be configured to take charge of all controls such as operations and operation procedures of the five workpiece transfer devices 2a to 2e. Moreover, the form which supervises the control apparatuses 23a-23e of each workpiece conveyance apparatus 2a-2e shown in FIG. 23 may be sufficient.

<< Other >>
Heretofore, the embodiment of the workpiece transfer device of the present invention has been described. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

  For example, in the above-described embodiment, the gantry loader is used as the workpiece transfer apparatuses 2a to 2c, but other types of loaders may be used. The configuration of the transfer robot 20 is not particularly limited. Instead of the Y-axis telescopic arm 201 shown in FIG. 3, a swing arm that swings in the front-rear direction may be arranged.

  In the above embodiment, in step 10 of FIG. 17, the transport path of the workpiece W is switched from the shortest time path L2 shown in FIG. 19 to the shortest distance path L3 shown in FIG. However, the conveyance path of the workpiece W before switching to the shortest distance path L3 is not particularly limited. For example, the downward E-shaped conveyance path L1 shown in FIG. 16 may be used. Moreover, the conveyance path | route of the workpiece | work W may be three-dimensional. For example, the workpiece W may be conveyed not only in the vertical and horizontal directions but also in the longitudinal direction.

  In the above embodiment, in step 24 and step 25 in FIG. 22, the steady operation is reset when the number of executions of the code outside the steady operation k> the threshold value N2. However, the steady operation need not be reset. That is, step 24 and step 25 may be deleted. In this case, the steady operation of the storage unit 230c shown in FIG. For this reason, it is not necessary to redetermine the steady operation in Step 6 of FIG.

  Further, after the number of continuous executions of the operation pattern (hereinafter referred to as “first specified number of times”) in the case where the steady operation is first determined in step 6 of FIG. 17, and after the steady operation is reset in step 25 of FIG. The number of continuous executions of the operation pattern (hereinafter referred to as “second prescribed number”) when the steady operation is re-determined in step 6 in FIG. 17 may be the same or different. For example, the first specified number of times and the second specified number of times may be the same number. Further, the second specified number of times may be less than the first specified number of times. The operator can freely set the first specified number of times and the second specified number of times.

  In the above embodiment, the workpiece unloading process (FIGS. 12 to 15) and the workpiece machining process are executed in parallel. However, the workpiece carry-in process (FIGS. 5 to 7) and the workpiece machining process may be performed in parallel. Moreover, you may perform a workpiece carry-out process and a workpiece carry-in process, and a workpiece processing process in parallel.

  In the above embodiment, in step 4 of FIG. 17, as shown in FIG. 18, the control device 23 cuts the instantaneous maximum torque for the robot travel motor 25 and the robot arm vertical axis motor 24 to A torque limit instruction was issued so that only the maximum torque within the torque could be output.

  However, the control device 23 cuts the maximum torque within the rated torque to the robot travel motor 25 and the robot arm vertical axis motor 24 so that only the limit torque shown in FIG. May be issued.

  In this way, the power consumption of the transfer robot 20 can be reduced. Further, for example, damage to the workpiece W or the transfer robot 20 due to an impact during transfer due to sudden acceleration or sudden deceleration can be reduced. Further, even if the workpiece W or the transfer robot 20 interferes or collides with an adjacent member or the like during transfer, damage to the workpiece W, the transfer robot 20 or the adjacent member can be reduced.

  In the above embodiment, the correction value X is calculated according to the equation (1) in Step 4 of FIG. However, when the cycle time Ts required for steady operation may be extended, such as when there is a margin in the production plan, the cycle time Ts may be changed to the cycle time Tc (Tc> Ts).

The new cycle time Tc is input to the control device 23 by the operator via the input device 27 shown in FIG. The correction value X after the change of the cycle time is calculated by the following equation (3) as the transport movement time Ti and the preceding and following process waiting time Tw.
X = [Ti / {Ti + Tw + (Tc−Ts)}] × 100 (3)
Thus, the cycle time itself may be changed according to the operator's instruction.

2a to 2e: Work transfer device, 20: Transfer robot, 21: Robot traveling table, 22: Support column, 23: Control device, 23a-23e: Control device, 24: Robot arm vertical axis motor, 25: Robot travel motor, 26: motor for turning the robot chuck, 27: input device, 200: travel axis slide, 201: Y-axis telescopic arm, 202: robot arm, 203: robot chuck, 204: main body, 230: computer, 230a: input / output interface, 230b: arithmetic unit, 230c: storage unit.
3a to 3e: machining center, 30: bed, 31: headstock, 32: tool axis side slide, 310: X axis lower slide, 311: X axis slide, 312: main body, 313: main axis side chuck, 314: X axis motor 315: Rotation motor, 320: Z axis lower slide, 321: Z axis slide, 322: Column, 323: Y axis lower slide, 324: Y axis slide, 325: Y axis motor, 326: Z axis motor, 327: Tool axis.
4a: Unprocessed workpiece supply device, 4b: Interprocess relay device, 4c: Interprocess relay device, 4d: Machining completed work stocker device, 4e: Interprocess relay device, 4f: Interprocess relay device, 40: Table, 44 : Shift device, 45: Tray.
8: Transport line, 80: Host control device (control device).
9: Production line.
L1: transport path, L2: shortest time path, L3: shortest distance path, P1: workpiece loading position, P2: workpiece machining position, P3: workpiece unloading position, R: safety area, T: tool, W: workpiece.

Claims (4)

A transport robot that transports the workpiece along the transport path from the workpiece loading position to the workpiece unloading position;
A control device for controlling the transfer robot;
A workpiece transfer device comprising:
The transport path is set so that the transport robot and the workpiece pass through a safe area that can move without interfering with adjacent members,
When the transfer robot has a waiting time for at least one of the workpiece loading position and the workpiece loading position,
The control device can execute path switching control for switching the transport path from a shortest time path set in a curved line in the safety area to a shortest distance path set in a broken line in the safety area. There is a workpiece transfer device.   The workpiece transfer apparatus according to claim 1, wherein the shortest distance path has a longer transfer movement time and a shorter transfer movement distance than the shortest time path. The control device sets the travel time of the shortest distance route to Tj, the travel time of the shortest time route to Ti, and the waiting time to Tw. The work conveyance apparatus according to claim 1 or 2 which switches to a distance course.
Tj-Ti <Tw Any one of the workpiece transfer devices on a transfer line that transfers a plurality of workpiece transfer devices in series,
4. The work transfer device according to claim 1, wherein the waiting time is generated by a cycle time of the work transfer device serving as a bottleneck among the plurality of work transfer devices of the transfer line. 5.

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