JP2005138242A - Tool breakage detection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tool breakage detection apparatus which quickly detects the breakage of a tool, and sets a new tool in parallel with the detection of the breakage, and shortens the breakage detection time. <P>SOLUTION: An old tool gripping device 17 for gripping an old tool To and a new tool gripping device 18 for gripping a new tool Tn are mounted on the tip end portion of a tool changing arm 15 so as to be close to each other. The feeler 26 of a touch sensor 29 is held at the position, which is nearly equivalent to the terminal point of the swiveling movement trajectory of the old tool gripping device 17, in a state in which the old tool gripping device 17 is held at a waiting position P1 and the new tool gripping device 18 is stationary at a tool inlet/exit position P3 of the new tool Tn. For this reason, the state of the breakage at the tip end of the old tool To is quickly detected after the old tool To has been drawn out from a main spindle. As a result, the operation for changing the new tool and the old tool is quickly carried out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tool breakage detection device that can detect the presence or absence of breakage of a tip of a used tool that has machined a workpiece in a machine tool.

  Machine tools are equipped with an automatic tool changer to automatically replace a used old tool with a new tool in a tool magazine when a workpiece is machined with a tool attached to the spindle and the machining operation is completed. ing. This automatic tool changer receives an old tool from a spindle and a tool loading / unloading mechanism from a tool magazine by means of a tool change arm provided with an old tool gripper for gripping an old tool and a new tool gripper for gripping a new tool. The new tool moved to the tool loading / unloading position is received. Then, the old and new tools are exchanged by turning the tool exchange arm 180 degrees.

In order to detect the breakage of the tip of the old tool, a tool that moves the old tool gripped by the tool changer arm along with the tool changer arm in the axial direction and makes the tip of the old tool contact the touch sensor. A breakage detection device has been proposed. (See Patent Document 1)
In order to detect the broken state of the old tool, there has also been proposed a tool breakage detecting device provided with a touch sensor that comes into contact with the tip of the old tool in correspondence with the turning trajectory of the old tool gripper. (See Patent Document 2)
In addition, in order to detect the breakage state of the old tool, we propose a tool breakage detection device that uses a non-touch type photoelectric sensor that detects breakage of the tip of the old tool in correspondence with the turning movement trajectory of the old tool gripper. Has been. (See Patent Document 3)
JP-A-11-90786 JP 2001-138180 A JP2000-176776

  However, in the tool breakage detection device described in Patent Document 1, the old tool held by the tool change arm is moved in the axial direction, and the tip of the tool is brought into contact with the touch sensor. There is a problem that the detection time of the broken state becomes long.

  Moreover, in the tool breakage detection apparatus described in Patent Document 2, since the touch sensor is arranged on the turning trajectory of the old tool gripper, the load on the touch sensor is increased because the touch sensor is in contact with the turning tool. There is a problem that the detection failure or the life of the touch sensor is reduced.

  Furthermore, in the apparatus described in Patent Document 3, the new tool is attached to the gripping tool immediately after the old tool is gripped by the gripping tool of the tool changing arm due to the characteristics of the automatic tool changer. The problem of detecting the passage of a new tool can occur. In order to cope with this problem, a method such as devising control or retracting the photoelectric sensor is required, but not only the control or the device itself becomes complicated, but also the detection time of the broken state is long. There was a problem of becoming.

  The present invention solves the above-mentioned problems in the conventional technology, can quickly detect the breakage of the tool, and can install a new tool in parallel with the detection of the breakage. It is another object of the present invention to provide a tool breakage detection device that can detect only an old tool.

  In addition to the above object, another object of the present invention is to provide a tool breakage detection device that can reduce the load applied to the touch sensor and extend its life.

  In order to solve the above-mentioned problems, the invention described in claim 1 is characterized in that an old tool gripping tool that grips an old tool at the tip of a tool change arm that is rotated forward and backward at a predetermined position, and a new tool that grips a new tool. The tool gripper is mounted so that the phase angle is 180 degrees or less, and the old tool gripper moves from the tool change position corresponding to the spindle to the standby position via the tool loading / unloading position corresponding to the tool magazine. Among them, the gist is that a touch sensor that comes into contact with the tip of the old tool is arranged on the movement trajectory between the tool loading / unloading position and the standby position.

  According to a second aspect of the present invention, in the first aspect, the touch sensor is configured such that the detection position is automatically adjusted by the position adjustment mechanism in accordance with the length dimension of the old tool. The gist.

The gist of a third aspect of the present invention is that, in the first or second aspect, the phase angle of both gripping tools with respect to the turning direction of the tool changing arm is set to 10 degrees to 45 degrees.
The gist of the invention of claim 4 is that, in claim 3, the touch sensor is provided in the vicinity of the standby position.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the touch sensor includes a tilt arm that reciprocally rotates at a predetermined position, and an elastically deformable attached to a tip of the tilt arm. And a proximity switch that is supported at a predetermined position and arranged in correspondence with the rotation trajectory of the proximal end portion of the tilting arm.

  In the invention according to any one of claims 1 to 5, the old tool gripper receives the old tool from the spindle and moves to the standby position, and the new tool gripper is moved from the spindle side to the tool loading / unloading position. In the process up to this point, breakage of the tip of the old tool can be detected by the touch sensor on the movement trajectory of the old tool gripper from the tool loading / unloading position to the standby position. For this reason, breakage detection of a tool can be quickly performed, and a new tool can be attached to a new tool gripper in parallel with breakage detection, so that detection time can be shortened. Further, since the new tool gripper does not move to the standby position of the old tool gripper, only the breakage of the old tool can be reliably detected.

  According to the second aspect of the present invention, the detection position of the touch sensor is automatically adjusted by the position adjustment mechanism according to the length dimension of the old tool, so that it is not necessary to perform troublesome position adjustment manually. There are advantages.

In the invention according to claim 3, since the phase angle of the two gripping tools with respect to the turning direction of the tool changing arm is set to 10 degrees to 45 degrees, the detection time can be further shortened.
According to the fourth aspect of the present invention, since breakage is detected in the vicinity of the standby position where the turning speed of the old tool gripper decreases, it is possible to reduce the load applied to the touch sensor and extend its life.

Hereinafter, an embodiment of a tool breakage detection apparatus embodying the present invention will be described with reference to the drawings.
FIG. 3 is a front view showing the entire machine tool. A main shaft 12 is mounted on the frame 11 by a drive mechanism (not shown) so as to be able to reciprocate in the X axis (left and right in FIG. 2) direction, Y axis (up and down in FIG. 2) direction, and Z axis (perpendicular to the plane of FIG. 2). ing. A tool magazine 13 for stocking old and new tools is mounted on the frame 11. Further, an automatic tool changer 14 for exchanging a used old tool To mounted on the spindle 12 and a new tool Tn stocked in the tool magazine 13 is mounted on the upper portion of the frame 11.

  The automatic tool changer 14 carries in new and old tools between a tool changer arm 15 mounted at a predetermined position of the frame 11 so as to be able to rotate forward and reverse by a servo motor (not shown), and between the tool magazine 13 and the tool changer arm 15. It is comprised by the tool carrying-in / out mechanism 16 for taking out. An old tool gripping tool 17 for gripping the old tool To and a new tool gripping tool 18 for gripping the new tool Tn are mounted on the tip of the tool exchange arm 15. As shown in FIG. 1, the phase angle α with respect to the turning center O of the tool exchange arm 15 of the old tool gripping tool 17 and the new tool gripping tool 18 is set to 180 degrees or less. The phase angle α is desirably 10 degrees to 45 degrees, and in this embodiment is 30 degrees.

  The old tool gripping tool 17 is reciprocally swung between the tool change arm 15 and the tool change position P2 corresponding to the spindle 12 from the standby position P1 shown in FIG. The new tool gripping tool 18 is reciprocally swiveled between the tool loading / unloading position P3 shown in FIG. 4 and the corresponding tool changing position P2 by the tool changing arm 15.

  The tool loading / unloading mechanism 16 stores the old tool To moved from the spindle 12 to the tool loading / unloading position P3 in the tool magazine 13 and unloads the new tool Tn in the tool magazine 13 to the tool loading / unloading position P3. It is configured. The tool loading / unloading mechanism 16 includes a tool pot 20 for loading / unloading the new tool Tn or the old tool To together with the tool holder 19, but description of the moving mechanism is omitted. In addition, the old tool gripping tool 17 and the new tool gripping tool 18 are provided with a mechanism for locking or unlocking the gripped tool holder 19, but the description of this configuration and operation is also omitted.

Next, a tool breakage detection apparatus that is a main part of the present invention will be described.
As shown in FIGS. 1 and 2, a movable support 22 is attached to the upper surface of the frame 11 via a bracket 21, and a tilting arm 24 is attached to the tip of the movable support 22 via a mounting plate 23. The shaft 25 is supported so as to be tiltable about the shaft 25. A contact 26 formed by connecting an elastically deformable bar spring and a coil spring in series is attached to the lower end of the tilt arm 24. The contact 26 is disposed in the vicinity of the standby position P1 on the movement trajectory in which the old tool gripper 17 that grips the old tool To pivots from the tool loading / unloading position P3 to the standby position P1. A proximity switch 27 is attached to the front surface of the attachment plate 23, and an actuator 28 is fitted to the upper base end portion of the tilt arm 24. In this embodiment, the tilt sensor 24, the contact 26, the proximity switch 27, the actuator 28, and the like constitute a touch sensor 29.

  Therefore, when the old tool To is swung from the tool loading / unloading position P3 to the standby position P1, and the contact 26 is pushed by the tip of the old tool To in the vicinity of the standby position P1, the tilt arm 24 is tilted. When the actuator 28 corresponds to the proximity switch 27, it is detected that the old tool To is normal. On the other hand, when the tip of the old tool To is broken and the contact 26 is not pushed, the tilt arm 24 remains stopped at a predetermined position, and the actuator is operated within a predetermined detection time. 28 does not correspond to the proximity switch 27, and the broken state of the tip of the old tool To is detected.

  2 are stored in advance in a storage medium provided in a control device (not shown) for outputting a control signal for operating the machine tool. Then, according to the length dimension of the old tool to be replaced, the movable support 22 is adjusted in the axial direction of the old tool To by a position adjusting mechanism (not shown), and the contact 26 is arranged at the tip of the old tool To. It is moved to an appropriate position where a broken state can be detected.

Next, the operation of the tool breakage detection apparatus configured as described above will be described.
1 and 4 show an initial state in which the tool changing arm 15 is rotated upward, the old tool gripping tool 17 is stopped at the standby position P1, and the new tool gripping tool 18 is stopped at the tool loading / unloading position P3. In this state, after the work processing operation of the workpiece by the tool held on the spindle 12 is completed, in order to replace the used old tool To with the new tool Tn on the tool magazine 13 side, the tool change arm 15 is used as shown in FIG. Rotate counterclockwise from the initial position indicated by the solid line and stop at the reverse position indicated by the two-dot chain line. As a result, the old tool gripping tool 17 stops moving to the tool change position P2 corresponding to the main shaft 12, and the new tool gripping tool 18 is held near the right side of the main shaft 12. In this state, the main shaft 12 is moved upward (Y-axis), the old tool To is fitted to the old tool gripping tool 17, the main shaft 12 is retracted in the Z-axis direction, and the old tool To is gripped by the old tool. Delivered to the tool 17.

  Next, when the tool changing arm 15 is rotated in the clockwise direction from the reverse position shown by the two-dot chain line in FIG. 4, the old tool holding tool 17 holding the old tool To as shown in FIG. At P1, the empty new tool gripper 18 is stopped at the tool loading / unloading position P3. At this time, in a normal state where the tip of the old tool To is not broken, the contact 26 is pushed by the tip of the old tool To, and the tilting arm 24 rotates counterclockwise about the shaft 25. It is detected that the old tool To is normal because the actuator 28 corresponds to the proximity switch 27.

  In FIG. 5, the tool pot 20 of the tool loading / unloading mechanism 16 that has been waiting above the new tool gripping tool 18 is lowered in the Y-axis direction, the new tool Tn is moved to the tool loading / unloading position P3, and the new tool Tn is moved. It is delivered to the new tool gripping tool 18. In this delivery operation, the tool pot 20 descends, and after the tool holder 19 of the new tool Tn is fitted to the new tool gripping tool 18, the tool pot 20 moves backward in the Z-axis direction and is separated from the tool holder 19. Is done.

  Thereafter, in FIG. 5, when the tool changing arm 15 is rotated counterclockwise by a predetermined angle (30 degrees), the old tool gripping tool 17 that grips the old tool To as shown in FIG. It is moved to the carry-in / out position P3. In this state, the old tool To held by the old tool gripper 17 is transferred to the tool pot 20 together with the tool holder 19, the tool pot 20 is moved upward, and the old tool To is moved to the tool magazine by the tool loading / unloading mechanism 16. 13.

  Next, in FIG. 6, the tool change arm 15 is rotated counterclockwise, and the new tool gripping tool 18 is moved to the tool change position P2 as shown in FIG. The new tool Tn is mounted on the spindle 12 together with the tool holder 19 by being advanced in the direction. Thereafter, the spindle 12 is lowered in the Y-axis direction, and the mounting of the new tool Tn is completed.

  Finally, in FIG. 7, the tool change arm 15 is rotated by a predetermined angle in the clockwise direction, and both tool grippers 17 and 18 that have become empty are moved to the standby position P1 and the tool change position P2 shown in FIG. .

According to the tool breakage detection apparatus of the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the old tool gripping tool 17 and the new tool gripping tool 18 are mounted at the phase angle α of 180 degrees or less with respect to the distal end portion of the tool changing arm 15, and the old tool gripping tool 17 is at the standby position P1. In the stroke in which the movement is stopped, the breakage of the old tool To is detected by the touch sensor 29, and the new tool gripping tool 18 is moved to the tool loading / unloading position P3. For this reason, since the breakage of the old tool To is detected in parallel with the delivery operation of the new tool Tn to the new tool gripper 18, the breakage can be detected quickly and the detection time can be shortened. it can.

(2) In the above embodiment, since the new tool gripping tool 18 does not move to the standby position P1 of the old tool gripping tool 17, only breakage of the old tool To can be reliably detected.
(3) In the embodiment described above, the detection position of the touch sensor 29 is automatically adjusted by the position adjustment mechanism in accordance with the length dimension of the old tool To, so that it is not necessary to perform troublesome position adjustment manually. There is an advantage that it can be done.

  (4) In the above embodiment, since the phase angle α of both gripping tools with respect to the turning direction of the tool changing arm 15 is set within the range of 10 degrees to 45 degrees, the breakage detection time of the old tool can be shortened. Can be planned.

  (5) In the above embodiment, since the breakage is detected by the contactor 26 in the movement trajectory immediately before the standby position P1 where the turning movement speed of the old tool gripping tool 17 decreases, the load on the touch sensor 29 is reduced. And the lifetime can be extended.

In addition, you may change the said embodiment as follows.
In the above embodiment, the phase angle α of the old tool gripping tool 17 and the new tool gripping tool 18 is set to 30 degrees, but it may be set to an arbitrary angle within 180 degrees.

  In place of the proximity switch 27, for example, a photoelectric sensor or a contact type switch may be used.

The principal part enlarged front view which shows one Embodiment of the tool breakage detection apparatus in the machine tool of this invention. The enlarged side view of a tool breakage detection apparatus. The front view which shows the whole machine tool. Explanatory drawing which shows the breakage detection operation | movement of a tool. Explanatory drawing which shows the breakage detection operation | movement of a tool. Explanatory drawing which shows the breakage detection operation | movement of a tool. Explanatory drawing which shows the breakage detection operation | movement of a tool.

Explanation of symbols

  α ... phase angle, P1 ... standby position, P2 ... tool change position, P3 ... tool loading / unloading position, Tn ... new tool, To ... old tool, 12 ... spindle, 13 ... tool magazine, 15 ... tool change arm, 17 ... Old tool gripping tool, 18 ... new tool gripping tool, 24 ... tilting arm, 26 ... contact, 27 ... proximity switch, 29 ... touch sensor.

Claims (5)

Attach the old tool gripping tool that grips the old tool and the new tool gripping tool that grips the new tool to the tip of the tool exchange arm that rotates forward and backward at a predetermined position so that the phase angle is 180 degrees or less, The tip of the old tool on the movement locus of the tool loading / unloading position and the standby position among the movement locus where the old tool gripper moves from the tool change position corresponding to the spindle to the standby position via the tool loading / unloading position corresponding to the tool magazine A tool breakage detection device, comprising a touch sensor that contacts the part. The tool breakage detection device according to claim 1, wherein the touch sensor is configured such that the detection position is automatically adjusted by a position adjustment mechanism in accordance with a length dimension of the old tool. The tool breakage detection device according to claim 1 or 2, wherein a phase angle of the two gripping tools with respect to a turning direction of the tool exchange arm is set to 10 degrees to 45 degrees. The tool breakage detection apparatus according to claim 3, wherein the touch sensor is provided in the vicinity of the standby position. 5. The touch sensor according to claim 1, wherein the touch sensor is supported at a predetermined position by a tilting arm that is reciprocally rotated at a predetermined position, an elastically deformable contact attached to a tip of the tilt arm. A tool breakage detecting device comprising: a proximity switch disposed in correspondence with a turning locus of a base end portion of the tilt arm.

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