JP2019209413A - Abnormality detection system, abnormality detection method, and boring machine, and boring method - Google Patents

Abstract

To easily add an abnormality detection function of a tool to an automatic boring machine of an air drive type.SOLUTION: An abnormality detection system includes: a sensor which is mounted to a boring machine performing operation of rotating a tool by rotating at least a spindle using air, and detects vibration or rotational frequency of at least either the tool or the spindle; and a signal processing unit wich detects boring abnormality on the basis of the vibration or rotational frequency detected by the sensor. The signal processing unit is configured to detect the boring abnormality in a period determined on the basis of the air.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to an abnormality detection system, an abnormality detection method, a drilling machine, and a drilling method.

  2. Description of the Related Art Conventionally, various machining apparatuses such as a punching machine are often provided with a device for detecting a machining abnormality (see, for example, Patent Document 1 and Patent Document 2). For example, an electric drilling machine having a function of detecting an abnormality in a drill by monitoring fluctuations in electric power and torque is commercially available. On the other hand, the drilling operation is shifting from manual operation by an operator using a hand-held drill driving device to machining by an automatic drilling machine (for example, see Patent Document 3).

JP 2013-049105 A JP-A-5-337790 Japanese Patent Laid-Open No. 2006-175157

  However, in the case of an automatic drilling machine that is not electrically driven, such as an air-driven automatic drilling machine, fluctuations in power and torque cannot always be monitored easily. For this reason, it is difficult to easily add an abnormality detection function for punching later to an air-driven automatic punching machine.

  Therefore, an object of the present invention is to make it possible to easily add a tool abnormality detection function to an air-driven automatic drilling machine.

  An abnormality detection system according to an embodiment of the present invention is attached to a drilling machine that performs an operation of rotating a tool by rotating at least a spindle with air, and detects vibration or rotation speed of at least one of the tool and the spindle. A sensor and a signal processing unit that detects a perforation abnormality based on the vibration or rotation speed detected by the sensor, and the signal processing unit detects the perforation abnormality during a period determined based on the air. It is comprised as follows.

  In addition, the abnormality detection method according to the embodiment of the present invention detects vibration or rotational speed of at least one of the tool and the spindle in a drilling machine that performs an operation of rotating the tool by rotating at least the spindle with air. A sensor is attached, and a perforation abnormality is detected based on vibration or rotation speed detected by the sensor during a period determined based on the air.

  Moreover, the drilling machine which concerns on embodiment of this invention is equipped with the abnormality detection system mentioned above.

  Moreover, the drilling method which concerns on embodiment of this invention manufactures a product or a semi-finished product by drilling a to-be-cut material with the drilling machine mentioned above.

The block diagram of the drilling machine provided with the abnormality detection system which concerns on the 1st Embodiment of this invention. The figure which shows the example of the method of attaching the sensor shown in FIG. 1 to a fixture so that attachment or detachment is possible. The figure which shows the example which provided the guide for sensor positioning in the fixing tool shown in FIG. The block diagram of the drilling machine provided with the abnormality detection system which concerns on the 2nd Embodiment of this invention.

  An abnormality detection system, an abnormality detection method, a drilling machine, and a drilling method according to embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
(Configuration and function of abnormality detection system and drilling machine)
FIG. 1 is a configuration diagram of a drilling machine equipped with an abnormality detection system according to a first embodiment of the present invention.

  The punching machine 1 includes an abnormality detection system 2. The abnormality detection system 2 can be attached to the drilling machine 1 as an attachment for detecting a drilling abnormality due to damage to the tool T such as a drill or a reamer. The drilling machine 1 to which the abnormality detection system 2 is attached is an air-driven drilling machine that performs an operation of rotating the tool T by rotating at least a spindle (main shaft) with air. The drilling machine 1 can be provided with not only an air-driven rotating device that rotates the tool T by air, but also an air-driven feeding device that feeds the tool T in the tool axis direction by air.

  The abnormality detection system 2 is a system that detects a drilling abnormality based on the vibration or rotation speed of at least one of the tool T and the spindle. The abnormality detection system 2 can be composed of a sensor 3, a flow sensor 4, and a signal processing unit 5.

  The sensor 3 is a vibration sensor or a rotation speed sensor that detects a vibration or rotation speed of at least one of the tool T and the spindle, which is a parameter acquired for detecting a drilling abnormality. Therefore, the sensor 3 is attached to the drilling machine 1. The rotational speed of the tool T and the rotational speed of the spindle are the same. Therefore, when detecting the rotational speed, if the rotational speed of one of the tool T and the spindle is detected, the rotational speed of the other is inevitably detected.

  On the other hand, since the tool T is coupled to the spindle, vibrations generated by the tool T and the spindle propagate to each other. For this reason, depending on the mounting position of the vibration sensor, a vibration obtained by synthesizing vibrations generated by the tool T and the spindle is detected. That is, as the vibration sensor mounting position is set to a position farther from the spindle, while the position closer to the tool T is set, a vibration having a dominant vibration component of the tool T is detected. On the contrary, while the vibration sensor is attached to a position farther from the tool T, the vibration with the dominant vibration component of the spindle is detected as the position is closer to the spindle.

  When the abnormality detection system 2 is attached to the punching machine 1 later, the punching machine 1 has no structure for attaching the sensor 3. Therefore, a fixture 6 such as a metal fitting for fixing the sensor 3 to the drilling machine 1 is attached to the casing of the drilling machine 1 or a holder of the tool T with a fastening tool such as a screw, and the sensor 3 is attached to the fixture 6. Can be installed.

  If the contact-type sensor 3 is arranged on the holder of the tool T or the like, it is possible to improve the detection sensitivity of vibration or rotational speed. However, the sensor 3 may break down due to an impact when the tool T is replaced or a collision of the tool T. Further, there is a possibility that the signal line connected to the sensor 3 becomes an obstacle when the tool T is replaced.

  Therefore, after attaching the abnormality detection system 2 to the punching machine 1, the fixture 6 is always fixed to the drilling machine 1, while only the sensor 3 can be configured to be detachable from the fixture 6. Thereby, the tool T can be easily exchanged while avoiding the failure of the sensor 3 due to the exchange of the tool T.

  As a method of detachably attaching the sensor 3 to the fixture 6, a method using a double-sided tape or a method of tightening with a screw can be considered. However, in the method using the double-sided tape, the strength for holding the sensor 3 is low and the reproducibility of attaching the sensor 3 at the same position is low. On the other hand, in the case of the method of tightening with screws, it is necessary to attach and detach the screws.

  FIG. 2 is a view showing an example of a method for detachably attaching the sensor 3 shown in FIG. 1 to the fixture 6.

  Therefore, as illustrated in FIG. 2, a magnet 6 </ b> A is provided on the fixture 6, and the sensor 3 can be detachably fixed with the magnet 6 </ b> A. That is, the sensor 3 can be detachably attached to a magnet 6 </ b> A that forms a sufficient magnetic field, such as a neodymium magnet provided on the fixture 6, by configuring the housing of the sensor 3 with a magnetic material. Thereby, the sensor 3 can be repeatedly attached to and detached from the fixture 6 easily and firmly without performing operations such as screw tightening.

  FIG. 3 is a view showing an example in which a guide 6B for positioning the sensor 3 is provided on the fixture 6 shown in FIG.

  As illustrated in FIG. 3, a guide 6 </ b> B for positioning the sensor 3 can be provided on the fixture 6. In the illustrated example, the housing of the sensor 3 is rectangular. For this reason, a rectangular frame for fitting the housing of the sensor 3 as the positioning guide 6B to the fixture 6 is formed. By providing such a guide 6 </ b> B for positioning the sensor 3 in the fixture 6, it is possible to ensure the repeated positioning accuracy of the sensor 3 with respect to the fixture 6.

  The flow rate sensor 4 provided separately from the sensor 3 such as the vibration sensor or the rotation speed sensor described above is a sensor that measures the flow rate of air for driving the drilling machine 1. Therefore, the flow sensor 4 is attached to the drilling machine 1 or the pipe 7 for supplying air to the drilling machine 1. In the example shown in FIG. 1, a flow sensor 4 is attached to a pipe 7 for supplying air to the perforator 1. The flow sensor 4 can be always attached after the abnormality detection system 2 is attached to the punch 1.

  An output side of the sensor 3 such as a vibration sensor or a rotation speed sensor and an output side of the flow rate sensor 4 are connected to the signal processing unit 5 through a signal line. That is, the detection signal of the vibration or rotation number of at least one of the tool T and the spindle acquired by the sensor 3 and the detection signal of the air flow rate detected by the flow sensor 4 are output to the signal processing unit 5.

  The signal processing unit 5 is a device that detects a drilling abnormality based on the vibration or the rotational speed of at least one of the tool T and the spindle detected by the sensor 3. The perforation abnormality can be detected by signal processing on the vibration or rotation number detection signal output from the sensor 3. Therefore, the signal processing unit 5 can be configured by an A / D (analog-to-digital) converter or an electric circuit such as a computer loaded with a program.

  If detection of drilling abnormality based on the vibration or rotation speed of at least one of the tool T and the spindle is always performed only by switching the power supply that supplies power to the signal processing unit 5, the amount of signal processing depends on the number of holes to be drilled. May increase and signal processing may become unrealistic. Therefore, the signal processing unit 5 can be configured to detect a drilling abnormality between the start and the end of the rotation of the tool T. The period from the start of rotation of the tool T to the end thereof can be determined by whether or not air for rotating the tool T is supplied to the drilling machine 1.

  For this reason, the signal processing unit 5 can detect the period from the start of rotation of the tool T to the end based on the air supplied to the drill 1 for driving the drill 1. More specifically, threshold processing for the detection signal of the air flow rate output from the flow sensor 4 to the signal processing unit 5 can be executed in the signal processing unit 5. Then, the perforation abnormality can be detected in the signal processing unit 5 during the period in which the flow rate measured by the flow sensor 4 is equal to or greater than the threshold or exceeds the threshold.

  The threshold value of the threshold value processing executed in the signal processing unit 5 can be determined to be equal to or lower than the lower limit value of the air flow rate for rotating the tool T or the like by a test. Thereby, it is possible to determine whether or not the air for rotating the tool T and the like is flowing through the air flow path to which the flow rate sensor 4 is attached by the threshold processing.

  Then, the detection of perforation abnormality is started by the fact that the air for performing the rotation of the tool T is detected by the flow sensor 4, while the air for performing the rotation of the tool T is detected by the flow sensor 4. The detection of the perforation abnormality can be terminated with the absence of the trigger. That is, the flow sensor 4 outputs to the signal processing unit 5 a trigger for instructing the start and end of measurement and recording of the vibration or the number of rotations of the tool T or the spindle for detecting the drilling abnormality in the signal processing unit 5. Functions as a switch. As a result, the perforation abnormality can be detected in the signal processing unit 5 only during the period determined based on the air.

  For example, when the rotation of the tool T and the feed in the tool axis direction are executed by separate air signals, the flow rate of the air signal for feeding the tool T can be detected by the flow sensor 4. In this case, based on the air flow rate detected by the flow sensor 4, the feed of the tool T is started and drilling is performed, and a signal is transmitted during the period during which the tool T returns to the original position in the tool axis direction again. The processing unit 5 can detect a perforation abnormality.

  On the other hand, when only the rotation of the tool T is executed by air, that is, when there is no feed function of the tool T, or when the rotation and the feed of the tool T are executed by common air, the flow rate of the air is measured. By detecting at the signal processing unit 5, it is possible to detect an abnormality in the drilling in the signal processing unit 5 during a period from the start to the end of the rotation of the tool T.

  The sensor 3 may be operated by supplying power from the power source only during a period in which the perforation abnormality is detected in the signal processing unit 5, or the sensor 3 is switched by turning on and off the power source. It is possible to operate, and recording and signal processing of the detection signal of the sensor 3 in the signal processing unit 5 may be executed only during a period determined based on air. For example, if the power consumption of the sensor 3 is small, the control of the sensor 3 can be simplified by controlling the sensor 3 to operate by switching the power on and off.

  Detection of abnormal drilling in the signal processing unit 5 can also be performed by signal processing including threshold processing for a detection signal representing the vibration or rotation speed of at least one of the tool T and the spindle output from the sensor 3. As a specific example, it is possible to determine that a perforation abnormality has occurred when an index value representing a characteristic of a waveform representing a time change in vibration or rotational speed detected by the sensor 3 is outside the allowable range.

  As an index value representing a waveform characteristic representing a time change of vibration or rotation speed, a desired parameter such as an amplitude or a peak value at a certain time can be adopted by a test. As a result of the test using various index values, it is preferable to evaluate the index value defined using the root mean square (RMS) and the index value defined using the kurtosis of the waveform. It was confirmed that the perforation abnormality can be detected with high accuracy. Therefore, when at least one of the first index value defined using the RMS of the waveform and the second index value defined using the kurtosis of the waveform is out of the permissible range in the signal processing unit 5 If a perforation abnormality is detected by an algorithm that determines that an abnormality has occurred, a perforation abnormality can be detected with good accuracy. Note that noise removal processing and normalization processing may be performed before and after the calculation of the index value.

  As another signal processing method for detecting the perforation abnormality, there are a waveform representing the time change of the vibration or the rotation number detected by the sensor 3 and a waveform serving as a reference corresponding to the case where no perforation abnormality has occurred. And a method of determining that a perforation abnormality has occurred when an index value representing a deviation amount such as a least-square error or a cross-correlation coefficient between or above the thresholds exceeds or exceeds a threshold.

  When detecting a drilling abnormality during the period from the start of rotation of the tool T to the end using air as a trigger, the tool T comes into contact with the work material after the rotation of the tool T is started. The signal processing unit 5 shows a waveform representing the vibration of the tool T or the spindle or the time change of the rotation speed until the tool T is retracted from the workpiece and the rotation of the tool T is completed after the drilling of the workpiece is completed. Will be obtained at.

  For this reason, for example, when the index value indicating the characteristic of the waveform representing the time change of the vibration or the rotational speed of the tool T or the spindle from the start to the end of the rotation of the tool T is out of the allowable range, the drilling abnormality Can be determined to have occurred. Alternatively, the threshold value is obtained by obtaining an index value representing the amount of deviation between the waveform representing the time variation of the vibration or the number of rotations of the tool T or the spindle from the start to the end of the rotation of the tool T and the reference waveform. By comparing with the above, it is possible to determine the presence or absence of perforation abnormality.

  That is, it is possible to calculate an index value that represents the characteristics of the waveform including the waveform during the period in which the tool T is not in contact with the workpiece, or to compare it with the reference waveform. Thereby, it becomes possible to detect a perforation abnormality without performing complicated signal processing for extracting a waveform during perforation from the waveform detected by the sensor 3. In other words, it is possible to detect an abnormality in drilling without detecting that drilling is in progress.

(Abnormality detection method and drilling method)
When the anomaly detection system 2 detects an anomaly in the drilling machine 1, the anomaly detection system 2 is attached to the drilling machine 1. Specifically, a sensor 3 that detects vibration or rotation speed of at least one of the tool T and the spindle is attached to the drilling machine 1 that performs an operation of rotating the tool T by rotating at least the spindle with air. An air flow sensor 4 is attached to a pipe 7 for supplying air to the perforator 1.

  In the case of drilling a workpiece while detecting a drilling abnormality with the drilling machine 1 provided with the abnormality detection system 2, air for rotating at least the spindle is supplied from the air supply system to the drilling machine 1. The supplied air is supplied to the perforator 1 through the pipe 7. As a result, the drilling machine 1 is driven and the workpiece is drilled.

  On the other hand, an air flow rate detection signal is output from the flow rate sensor 4 to the signal processing unit 5. Thereby, it is detected in the signal processing unit 5 that air has been supplied to the punching machine 1. That is, the signal processing unit 5 detects that the punching by the punching machine 1 has started. Then, based on the air detected by the flow sensor 4, the signal processing unit 5 vibrates at least one of the tool T and the spindle detected by the sensor 3 from the start to the end of the rotation of the tool T. Alternatively, a perforation abnormality is detected based on the rotation speed.

  Specifically, the vibration or rotational speed of at least one of the tool T and the spindle detected by the sensor 3 such as a vibration sensor or a rotational speed sensor is output to the signal processing unit 5. Then, the signal processing unit 5 determines whether or not a drilling abnormality has occurred by performing signal processing on the waveform signal representing the vibration or rotation speed of at least one of the tool T and the spindle. If it is determined that a perforation abnormality has occurred, information for notifying the user of the occurrence of the perforation abnormality can be output to a desired output device such as a display. Thereby, the user can confirm the presence or absence of perforation abnormality.

  If no drilling abnormality occurs, drilling of the workpiece by the drilling machine 1 can be continued. And a product or a semi-finished product can be manufactured by perforation of a material to be cut.

(effect)
The abnormality detection system 2, the abnormality detection method, the drilling machine 1 and the drilling method as described above are triggered by air for rotating the tool T, and the drilling abnormality is based on the vibration or the rotational speed of at least one of the tool T and the spindle. Is to be detected. For this reason, according to the abnormality detection system 2, the abnormality detection method, the punching machine 1, and the punching method, it is possible to add an abnormality detection function for drilling to the air-driven drilling machine 1 later.

  In addition, by detecting the perforation abnormality using the air supplied to the perforation machine 1 as a trigger, a period for recording the detection signal output from the sensor 3 to detect the perforation abnormality is recorded. It can be limited to the period from the start to the end. That is, the period for detecting the perforation abnormality can be automatically adjusted to the perforation period. Thereby, useless recording and signal processing of the detection signal output from the sensor 3 can be avoided.

(Second Embodiment)
FIG. 4 is a block diagram of a drilling machine equipped with an abnormality detection system according to the second embodiment of the present invention.

  The abnormality detection system 2A according to the second embodiment shown in FIG. 4 is different from the abnormality detection system 2 according to the first embodiment in that it can detect a perforation abnormality in the plurality of perforators 1. Since the other configurations and operations of the abnormality detection system 2A in the second embodiment are not substantially different from those of the abnormality detection system 2 in the first embodiment, the same or corresponding configurations are denoted by the same reference numerals. Description is omitted.

  When detecting a perforation abnormality in a plurality of perforators 1, the signal processing unit 5 can be shared between the perforators 1 as illustrated in FIG. That is, the common signal processing unit 5 can detect a perforation abnormality in the plurality of perforators 1.

  In that case, the sensor 3 for detecting the vibration or the rotational speed of at least one of the tool T and the spindle and the flow rate sensor 4 are attached to the plurality of drilling machines 1, respectively. The signal processing unit 5 targets a single or a plurality of punches 1 selected from the plurality of punches 1 based on the flow rates measured by the plurality of flow sensors 4 attached to the plurality of punches 1, respectively. As shown in FIG. That is, it is possible to detect a perforation abnormality only for the perforator 1 to which air is supplied.

  According to the second embodiment described above, in addition to the same effects as those of the first embodiment, in the case of detecting a perforation abnormality in the plurality of perforators 1, there is an effect that the configuration of the signal processing unit 5 can be simplified. can get.

(Other embodiments)
Although specific embodiments have been described above, the described embodiments are merely examples, and do not limit the scope of the invention. The novel methods and apparatus described herein can be implemented in a variety of other ways. Further, various omissions, substitutions, and changes can be made in the method and apparatus described herein without departing from the scope of the invention. The appended claims and their equivalents include such various forms and modifications as are encompassed by the scope and spirit of the invention.

1 Punching machine 2 Abnormality detection system 3 Sensor 4 Flow rate sensor 4
5 Signal Processing Unit 6 Fixing Tool 6A Magnet 6B Guide 7 Piping T Tool

Claims (12)

A sensor attached to a drilling machine that performs an operation of rotating the tool by rotating at least the spindle with air, and detecting a vibration or a rotational speed of at least one of the tool and the spindle;
A signal processing unit that detects perforation abnormality based on vibration or rotation speed detected by the sensor,
The abnormality detection system configured to detect the perforation abnormality during a period determined based on the air. A flow sensor for measuring the flow rate of the air;
2. The abnormality detection according to claim 1, wherein the signal processing unit is configured to detect the perforation abnormality during a period in which the flow rate measured by the flow sensor is equal to or greater than a threshold or exceeds a threshold. system. A sensor for detecting the vibration or rotation speed and the flow rate sensor are attached to a plurality of the perforators,
The signal processing unit detects the perforation abnormality for a perforator selected from the plurality of perforators based on the flow rates measured by the plurality of flow sensors attached to the plurality of perforators, respectively. The anomaly detection system of claim 2 configured to perform.   The signal processing unit is configured to determine that the perforation abnormality has occurred when an index value representing a characteristic of a waveform representing a temporal change in the vibration or the rotational speed detected by the sensor is out of an allowable range. The abnormality detection system according to any one of claims 1 to 3.   The signal processing unit performs drilling by contacting the workpiece after the tool starts rotating, and after the drilling of the workpiece is completed, the tool is retracted from the workpiece. The apparatus is configured to determine that the drilling abnormality has occurred when an index value representing a characteristic of a waveform representing a temporal change in the vibration or the rotational speed until the rotation of the tool is finished is out of an allowable range. Item 6. The abnormality detection system according to item 4.   In the signal processing unit, at least one of the first index value defined using the root mean square of the waveform and the second index value defined using the kurtosis of the waveform is out of an allowable range. The abnormality detection system according to claim 4 or 5, wherein the abnormality detection system is configured to determine that the perforation abnormality has occurred. A fixing device for fixing the sensor to the drilling machine;
The abnormality detection system according to any one of claims 1 to 6, wherein only the sensor is configured to be detachable from the fixture.   The abnormality detection system according to claim 7, wherein the fixture includes a magnet that detachably fixes the sensor.   The abnormality detection system according to claim 7 or 8, wherein a guide for positioning the sensor is provided on the fixture.   A drilling machine comprising the abnormality detection system according to any one of claims 1 to 9.   A punching method for manufacturing a product or a semi-finished product by punching a workpiece with the punching machine according to claim 10. A sensor for detecting vibration or rotation speed of at least one of the tool and the spindle is attached to a drilling machine that performs an operation of rotating the tool by rotating at least the spindle with air.
An abnormality detection method for detecting a perforation abnormality on the basis of vibration or rotational speed detected by the sensor during a period determined based on the air.

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