Working machinery

Abstract

A machine tool for raising the efficiency of step switching work for a robot hand in an automated workpiece transport device, the machine tool having: a processing device for performing a process on a workpiece within a processing chamber; an automated workpiece transport device for gripping the workpiece using a robot hand provided with a chuck mechanism and transferring the workpiece to and from the processing device; and a control device for controlling driving of the processing device and the automated workpiece transport device, the control device being provided with a step switching work unit that, after the processing device and the automated workpiece transport device have undergone an emergency stop for the purpose of step switching work with respect to the robot hand, causes the robot hand to move to a work position according to driving control with respect to the automated workpiece transport device.

Description

[Technical Field]

[0001] The present invention relates to a machine tool having an automatic workpiece transport device that grips and transports a workpiece with a robot hand, and that improves work efficiency when changing the position of the robot hand that is equipped with a chuck mechanism. [Background technology]

[0002] Machine tools are equipped with an integrated automatic workpiece transport device for transporting workpieces to internal processing devices. The automatic workpiece transport device has a robot hand equipped with a chuck mechanism for gripping the workpiece, and the workpiece is automatically transported by moving the robot hand. The automatic workpiece transport device, for example, carries out unmachined workpieces from a supply stocker, delivers them to the processing device inside the machine tool, and then removes the machined workpieces and transports them to a collection section. Workpieces processed by machine tools come in a variety of shapes, and when the type of workpiece is switched, a changeover operation is sometimes performed to replace the chuck jaws of the chuck mechanism with ones that correspond to the workpiece. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 3-68706 Summary of the Invention [Problem to be solved by the invention]

[0004] The machine tool described in Patent Document 1 automates the chuck replacement of an automatic workpiece transport device, but requires a storage table for storing the chuck, which increases the travel distance of the automatic workpiece transport device and results in a larger system. Therefore, chuck replacement in an automatic workpiece transport device is typically performed manually by an operator. To do so, the robot hand must be moved to a position where it is easier to perform the work, or the operator must approach the robot hand's location. However, when the robot hand's movement is controlled manually by the operator, there is a risk of the robot hand colliding with the machine and being damaged. Meanwhile, for an operator to perform work on a robot hand in a retracted position, a stepladder must be provided for a high work position, which places a heavy burden on the operator.

[0005] SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a machine tool that improves the efficiency of changeover work for a robot hand of an automatic workpiece transport device. [Means for solving the problem]

[0006] In one aspect of the present invention, a machine tool comprises a processing device that processes a workpiece within a processing chamber; an automatic workpiece transport device that grips the workpiece with a robot hand equipped with a chuck mechanism and transfers the workpiece between the processing device and the automatic workpiece transport device; and a control device that drives and controls the processing device and the automatic workpiece transport device, and has a changeover operation unit that brings the processing device and the automatic workpiece transport device to an emergency stop to perform a changeover operation on the robot hand, and then drives and controls the automatic workpiece transport device to move the robot hand to a work position. [Effects of the Invention]

[0007] According to the above configuration, when a changeover operation of the chuck jaws or the like is required for the robot hand of the automatic workpiece transport device, the processing device and the automatic workpiece transport device are brought to an emergency stop, and then drive control is performed on the automatic workpiece transport device, and for example, the robot hand is moved to a work position corresponding to an opening and closing door formed in the processing chamber, so that the worker can efficiently perform the changeover operation. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an external perspective view showing an embodiment of a machine tool; [Figure 2] 1 is a perspective view of an internal structure showing one embodiment of a machine tool; [Figure 3] FIG. 1 is a perspective view showing a mounting structure of an automatic workpiece transport device in a machine tool. [Figure 4] FIG. 2 is a side view showing the automatic workpiece transport device. [Figure 5] FIG. 1 is a diagram conceptually illustrating a control system for a machine tool. [Figure 6] FIG. 10 is a flowchart showing the processing of a stage change operation program. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of a machine tool according to the present invention will be described below with reference to the drawings. Fig. 1 is an external perspective view showing the machine tool of this embodiment, and Fig. 2 is a perspective view showing its internal structure. Fig. 3 is a perspective view showing the mounting structure of an automatic workpiece transport device in the machine tool, and Fig. 4 is a side view showing the automatic workpiece transport device. Furthermore, Fig. 5 is a conceptual diagram showing the control system of the machine tool.

[0010] This machine tool 1 is a multi-tasking machine that has various machining devices and thus functions as both an NC lathe and a machining center. Specifically, it is an opposed-axis two-axis lathe having a first workpiece spindle unit 3 and a second workpiece spindle unit 4 that grip a workpiece W, and a first turret unit 5 and a second turret unit 6 that hold multiple tools, each arranged symmetrically on the left and right. In addition, a tool spindle unit 2 is provided in the center of the machine body to perform machining that is difficult to perform with turret tools. In this embodiment, the direction parallel to the spindles of the coaxial first and second workpiece spindle units 3 and 4 is defined as the Z-axis, the vertical direction perpendicular to the Z-axis is defined as the X-axis, and the front-to-rear direction of the machine body perpendicular to the Z-axis is defined as the Y-axis.

[0011] The first and second work spindle units 3, 4 each have a spindle-side chuck attached to the spindle of the headstock, and are driven by a spindle motor to phase the gripped workpiece during machining and rotate at a predetermined speed. The first and second turret units 5, 6 are configured to rotate and index the multiple attached tools (turret tools) by controlling the rotation of an indexing servo motor, and the tools move relative to the workpiece gripped by the corresponding first or second work spindle unit 3, 4. The tool spindle unit 2 in the center of the machine has a spindle head that allows tools (spindle head tools) to be replaced, and is configured to be able to machine the workpiece gripped by the first or second work spindle unit 3, 4.

[0012] In machine tool 1, the above-mentioned devices are covered by a machine body cover 11, and a left front door 13 and a right front door 14 are formed on both the left and right sides of the front of the machine body, with an operation panel 15 that can swing about a vertical axis located in the center between them. Behind the left front door 13 is a first machining chamber 17 in which the first workpiece spindle unit 3 and the first turret unit 5 are located, and behind the right front door 14 is a second machining chamber 18 in which the second workpiece spindle unit 4 and the second turret unit 6 are located. The tool spindle unit 2 is located in the center of the machine where the operation panel 15 is located.

[0013] Machine tool 1 is provided with an automatic tool changer 7 in the front center of the body for automatically changing tools for the tool spindle device 2. Automatic tool changer 7 has a tool magazine 19 storing multiple tools (spindle head tools) provided on top, and has a tool changing mechanism that moves tools between the spindle head and the automatic tool changer 7. In machine tool 1, operation panel 15 is positioned at a height that allows operation at eye level of operator H, and so tool magazine 19 is positioned at an even higher height.

[0014] Machine tool 1 is provided with an automatic workpiece transport device 8 for automatically transporting workpieces to first workpiece spindle device 3 in first machining chamber 17 and second workpiece spindle device 4 in second machining chamber 18. Automatic workpiece transport device 8 has a rail base 33 fixed to the upper front part of frame structure 10, which is equipped with two traveling rails 31 and one traveling rack 32 in the width direction of the machine body, and a traveling table 34 that slides on traveling rails 31 is provided above the rail base 33. A Z-axis servo motor 35 is fixed to traveling table 34, and a pinion 36 fixed to the rotation shaft of the Z-axis servo motor 35 meshes with traveling rack 32, enabling movement in the width direction of the machine body.

[0015] A slide member is fixed to the upper surface of the traveling table 34, and a slide base 37 is provided with slide rails along which the slide member slides, and which moves in the fore-and-aft direction of the machine body. A fore-and-aft movement rack 38 is fixed to the side of the slide base 37, and a Y-axis servo motor 39 is fixed to the traveling table 34 via a bracket. Therefore, by meshing a pinion fixed to the rotation shaft of the Y-axis servo motor 39 with the fore-and-aft movement rack 38, the slide base 37 can move in the fore-and-aft direction. The slide base 37 protrudes forward from the frame structure 10, and a lifting arm 41 that moves up and down is attached to its tip.

[0016] A support column 42 equipped with a lifting rail is fixed in a vertical position to the slide base 37, and a lifting arm 41 equipped with a slide member is configured to move along the lifting rail. An X-axis servo motor 43 is fixed to the top of the support column 42, and a belt is stretched between a pulley fixed to the rotation shaft of the X-axis servo motor 43 and a pulley journaled at the bottom of the support column 42. The lifting arm 41 is connected to the belt, and can be moved up and down by driving the X-axis servo motor 43. A robot hand 45 for gripping a workpiece W is attached to the lower end of the lifting arm 41. The robot hand 45 is equipped with a pair of chuck mechanisms 48 on the front and back sides, and is configured to rotate about a rotation axis O in the Y-axis direction perpendicular to the lifting arm 41, allowing positioning in the up, down, left, and right directions.

[0017] Next, a control device 50 that controls the driving of the machine tool 1 has a microprocessor (CPU) 51, a ROM 52, a RAM 53, a non-volatile memory 54, an I / O unit 55, and the like, which are connected via a bus line 57. The CPU 51 controls the entire control unit, and the ROM 52 stores system programs and control parameters executed by the CPU 51, and the RAM 53 temporarily stores calculation data and the like.

[0018] The non-volatile memory 54 stores information necessary for processing executed by the CPU 51, such as a machining program for the multi-tasking machine 1 and a workpiece transport program for the automatic workpiece transport device 8, and in this embodiment, a stage change operation program for the robot hand 45. The control device 50 is provided with a programmable logic controller (PLC) 56 connected to an I / O unit 55, and drive units of various machining devices such as the tool spindle device 2 of the multi-tasking machine 1 are controlled by sequence programs created in ladder format.

[0019] Next, in the machine tool 1 configured as described above, predetermined machining is performed on the workpiece W in accordance with a machining program, etc. The workpiece W to be machined is carried from an entrance-side stocker to a machining position by the automatic workpiece transport device 8. The workpiece W held by the robot hand 45 is transported to the first workpiece spindle device 3 or the second workpiece spindle device 4, and after being handed over to the spindle-side chuck 11, predetermined machining is performed using a tool that has been swiveled and indexed by the first turret device 5 or the second turret device 6.

[0020] In the first machining by the first workpiece spindle device 3 and the second machining by the second workpiece spindle device 4, machining may be performed by the tool spindle device 2 in addition to machining by the first or second turret device 5, 6. To transport the workpiece W in the automatic workpiece transport device 8, the drive of the Z-axis servo motor 35, Y-axis servo motor 39 and X-axis servo motor 43 is controlled in accordance with a workpiece transport program, and the traveling table 34, slide table 37 and lift arm 41 move in the Z-axis, Y-axis or X-axis direction, and the workpiece W held by the robot hand 45 is transported to a predetermined position.

[0021] Incidentally, when the type of workpiece W to be machined is changed, the spindle chucks of the first and second workpiece spindle devices 3, 4 that grip the workpiece W and the robot hand 45 of the automatic workpiece transfer device 8 may need to have their chuck jaws replaced accordingly. This changeover work is performed by the worker H, which places a heavy workload on the automatic workpiece transfer device 8 in particular. This is because the spindle chucks of the first and second workpiece spindle devices 3, 4 are in their operating positions directly in front of the worker H when the left front door 13 or the right front door 14 is opened, but the robot hand 45 of the automatic workpiece transfer device 8 returns to the retracted position 20 (original position) shown by the dashed line in FIG. 3.

[0022] Therefore, when worker H replaces the chuck jaws of the robot hand 45, he or she must work at the retracted position 20 or manually move the robot hand 45 into, for example, the first machining chamber 17. The robot hand 45 is moved to the first machining chamber 17 because it is closer to the retracted position 20 than the second machining chamber 18. However, the robot hand 45 is in a high position at the retracted position 20, so worker H must prepare a stepladder and climb up it to work. On the other hand, to eliminate such troublesomeness, worker H can manually operate the automatic workpiece transport device 8 using an operation pendant and move the robot hand 45 to a position where the left front door 13 is opened.

[0023] However, manual operation by the operator H requires visual confirmation of the position of the robot hand 45 and the like, which can lead to collisions when moving the robot hand 45 into the first processing chamber 17. For example, a valve that protrudes slightly at the entrance where the shutter to the first processing chamber 17 opens and closes can collide with the object. If damage occurs due to a collision, repairs will be necessary, which will further increase the workload and extend the time until resumption of work. Furthermore, careful operation is required to avoid such collisions, which again results in a long time required for the changeover work.

[0024] Therefore, in this embodiment, a stage change operation program is provided for positioning the robot hand during stage change. Fig. 6 is a flowchart showing the processing of the stage change operation program. When chuck jaw replacement work is required, the emergency stop button on the operation panel 15 is pressed, the machine tool 1 is temporarily powered down and placed in a drive-stop state, and the stage change operation program is started. First, the start of stage change work for the robot hand 45 is confirmed by checking whether or not a power-on command has been issued after the emergency stop (S101). That is, when the operator H releases the emergency stop button, the power is turned on (S101: YES), and then it is confirmed whether or not an operation preparation command has been issued (S102).

[0025] When the operator H presses the operation preparation button (S102: YES), all of the drive units of the machine tool 1 are moved to the home position, which is the retreat position (S013). Since the retreat position 20 is the home position of the automatic workpiece transport device 8, the robot hand 45 returns to that position and stops there. Next, it is confirmed whether or not a command to start the changeover cycle has been issued to the robot hand 45 (S104). When the operator H presses the changeover cycle start button provided on the operation panel 15 (S104: YES), the automatic workpiece transport device 8 is controlled and the robot hand 45 is moved to the specified work position (S105).

[0026] The robot hand 45 moves in the Z-axis direction from its original position (retracted position 20) and stops above the first processing chamber 17 with the ceiling shutter open. Then, it descends in the X-axis direction and enters the first processing chamber 17, stopping at the work position. The work position for changing the stage is set at a height that is easy for the worker H to work at, such as 1,500 mm above the floor. The robot hand 45 also rotates around a rotation axis O to facilitate the replacement of the chuck jaws, and the pair of front and back chuck mechanisms 48 are positioned vertically. The chuck jaws are replaced using this robot hand 45. The work can be performed on the lower chuck as is, or the operation pendant can be used to turn the robot hand 45 upside down or to rotate the chuck mechanism 48 left or right.

[0027] In the stage changing work program, after the robot hand 45 stops at the work position, it is confirmed whether or not there is a stage changing cycle end command (S106). That is, when the chuck jaw replacement work for the robot hand 45 is completed, the operator H presses the stage changing cycle stop button provided on the operation panel 15 (S106: YES). This controls the automatic workpiece transport device 8 to move the robot hand 45 back to the evacuation position 20, which is the original position (S107), and the processing in the stage changing work program ends.

[0028] Therefore, according to this embodiment, the automatic workpiece transport device 8 is automatically controlled for the machine tool 1 in a drive-stop state, and the robot hand 45 is moved from the home position to the work position, so that the operator H can perform the work of changing the level of the chuck jaws right in front of him when he opens the left front door 13. Also, in this embodiment, since the drive parts of the machine tool 1 are all moved to the home position and put into a retracted state by the operation preparation, the robot hand 45 can be moved to the work position without collision.

[0029] Although one embodiment of the present invention has been described, the present invention is not limited to this, and various modifications are possible without departing from the spirit of the present invention. For example, in the above embodiment, the machine tool has been described using an example of a multi-tasking machine equipped with a gantry-type automatic workpiece transporter 9, but the present invention is not limited to this. [Explanation of symbols]

[0030] 1...machine tool 2...tool spindle device 3...first workpiece spindle device 4...second workpiece spindle device 5...first turret device 6...second turret device 7...automatic tool changer 8...automatic workpiece transport device 13...left front door 15...operation panel 17...first machining room 45...robot hand

Claims

1. a processing device that processes the workpiece in the processing chamber; an automatic workpiece transport device that grips a workpiece with a robot hand equipped with a chuck mechanism and transfers the workpiece between the robot hand and the processing device; a control device that drives and controls the processing device and the automatic workpiece transport device, and includes a changeover operation unit that brings the processing device and the automatic workpiece transport device to an emergency stop for a changeover operation on the robot hand, and then drives and controls the automatic workpiece transport device to move the robot hand to a work position; A machine tool having the above construction.

2. 2. The machine tool according to claim 1, wherein the changeover work unit of the control device brings the machining device and the automatic workpiece transport device to an emergency stop, and then moves all of the drive units of the machining device and the automatic workpiece transport device to their original positions in response to an operation preparation command.

3. 3. The machine tool according to claim 2, wherein the changeover work unit of the control device moves all of the drive units to their original positions in response to the operation preparation command, and then moves the robot hand from its original position to the work position in response to a changeover cycle start command.

4. 4. A machine tool according to claim 1, wherein the machining chamber has an opening / closing door formed on the front of the machine body, and the working position to which the robot hand is moved corresponds to the position to which the opening / closing door is opened.

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