JP2007147513A - Quality inspection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a quality inspection device for detecting vibration data accurately and sensitively by vibration-exciting a specimen stably. <P>SOLUTION: A vibration exciter 50 is set so that a potential core hits the specimen, and has a position adjusting mechanism 58 as an example of the adjusting means. The distance from the specimen of a panel 30 or the like to a blow out port of a nozzle 52 and the jet angle can be adjusted by adjusting the position of the nozzle 52 in the vertical, lateral longitudinal directions, orientation of the blow out port, angle thereof, or the like. The nozzle 52 is removably mounted and is replaceable. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a quality inspection apparatus that inspects an object such as a press-processed product.

When experimentally measuring vibration characteristics or the like of a subject or performing quality inspection, a hammering vibration method using a hammer is known. In this method, a subject is vibrated by hitting a part of the subject with a hammer, and the vibration is measured by a sensor.
JP-A-9-171008

  However, in the hitting vibration method as described above, the vibration data tends to vary depending on the force and angle at the time of hitting, and it is difficult to obtain accurate vibration data. Therefore, it was difficult to detect a minute change in vibration.

According to the first aspect of the present invention, in order to achieve the above-mentioned object, a vibration is applied to the subject by using a vibrating means to give a vibration, the vibration of the subject is detected by the vibration detecting means, and pass / fail is determined. The apparatus includes an adjusting unit that adjusts a collision state between the fluid and the subject, and is configured so that a potential core of the fluid collides with the subject.
In addition to the above, the invention described in claim 2 is provided with a replaceable nozzle in the vibration exciter so that at least one of the shape of the jet port, the diameter of the jet port, and the taper angle of the jet passage can be adjusted.
In addition to the above, the invention described in claim 3 is provided with adjusting means for adjusting the jet angle or jet distance of the fluid.

According to the first aspect of the present invention, since the adjusting means capable of changing the collision state between the fluid and the subject is provided and the potential core is in contact with the subject, the subject can be vibrated stably. . Therefore, accurate vibration data can be obtained, and changes in vibration can be detected sensitively.
According to invention of Claim 2, the said adjustment can be performed easily and correctly.
According to the third aspect of the present invention, the adjustment can be easily performed without being affected by the arrangement and shape of the subject or the position where the vibration means is provided.

Hereinafter, the quality inspection apparatus 1 according to the present embodiment will be described with reference to FIGS. In FIG. 2, the rear support portion 20 and the guide portion 40 are omitted.
As shown in FIG. 1 to FIG. 3, the quality inspection apparatus 1 mainly includes a plurality of support units 20, a vibrator 50, a plurality of sensor units 60, a plurality of guide units 40, etc. attached to a base table 10. Installed and configured as possible.

  The table 10 is an example of a base. The table 10 is installed, for example, at a predetermined position after the pressing step in the press line (shown in FIG. 9 (a)). The table 10 is made of metal or the like and has a flat upper surface 10a. The upper surface 10 a is configured to have the same size as the panel 30. A plurality of attachment portions 11 are provided on the upper surface 10a. In the plurality of attachment portions 11, the support portion 20, the vibration exciter 50, the sensor portion 60, the guide portion 40, and the like are detachably attached. In addition, when inspecting another member, all of the attachment structures of the plurality of attachment portions 11 are configured in the same manner so that these can be fixed at different positions.

  The table 10 includes a vibration isolation mechanism (not shown). The vibration isolation mechanism is, for example, an air spring or the like, and inspection accuracy is eliminated by removing external vibration (for example, vibration due to a press process disposed in the periphery) with respect to the sensor unit 60, the vibration exciter 50, the support unit 20, and the like. To prevent adverse effects. Three support portions 20 are provided on the upper surface 10a. The support part 20 supports the panel 30. Each of the three support portions 20 is located near the apex of a triangle centered on the center of the panel 30 when the panel 30 is installed. A triangle surrounded by the three support portions 20 is an example of a support region.

  As shown in FIG. 4, the support portion 20 has an attachment portion 21 at the lower end, and the attachment portion 21 is detachably attached to the table 10. A column portion 22 is formed above the attachment portion 21. The column portion 22 is formed in an elongated bar shape and is perpendicular to the upper surface 10 a of the table 10. The support column 22 is configured to be height-adjustable so as to be compatible with various shapes of subjects. A tip portion 23 is formed at the upper portion of the support column portion 22. The tip portion 23 has a hemispherical shape, and supports the panel 30 by making point contact with the lower surface of the panel 30 when the panel 30 is installed at a fixed position.

  The panel 30 is an example of a subject and serves as a door panel used for an automobile door. The panel 30 is formed by pressing a metal plate or the like into a predetermined shape by pressing. Specifically, it has a trapezoidal outer shape as indicated by a two-dot chain line in FIG. 1, and has a window hole 31 and the like.

  A plurality of guide portions 40 are provided at positions on the upper surface 10 a corresponding to the vicinity of the outer periphery of the panel 30. The guide part 40 is for arranging the panel 30 in a fixed position. As shown in FIG. 5, the guide portion 40 includes a bending portion 42 and an attachment portion 41 that supports the lower end portion 42 a of the bending portion 42. The guide part 40 is detachably attached to the table 10 via an attachment part 41.

  The lower end portion 42 a of the bending portion 42 is disposed at a position where the outer periphery of the panel 30 is installed. The upper part 42b of the curved part 42 extends curvedly outward from the lower end part 42a. When the panel 30 is placed from above the table 10, the panel 30 slides down from the upper part 42 b of the bending part 42 toward the lower end part 42 a, so that the panel 30 is accurately arranged at a fixed position.

  The attachment portion 41 and the bending portion 42 are connected via an escape mechanism 43. The relief mechanism 43 moves the bending portion 42 outward and retracts it from the panel 30 after the panel 30 is accurately placed and stabilized at a fixed position and before being vibrated.

  A vibration exciter 50 shown in FIGS. 6 and 7 excites the panel 30 by ejecting a fluid, and includes a nozzle 52, a regulating valve 53, a solenoid valve 54, a tank 55, a pressure increasing valve 56, a supply source. 57, a position adjusting mechanism 58 and the like. The vibration exciter 50 is detachably attached to the outside of the support area on the upper surface 10 a of the table 10 via the attachment portion 51, and is arranged near the outer periphery of the panel 30.

  The position adjusting mechanism 58 is an example of an adjusting means, and includes a horizontal position adjusting mechanism 58 (a), a vertical position adjusting mechanism 58 (b), and an angle adjusting mechanism 58 (c). The direction, angle, etc. of the spout can be adjusted. As a result, the distance from the subject such as the panel 30 to the ejection port of the nozzle 52 and the ejection angle can be adjusted.

  The nozzle 52 is a straight type and is arranged downward to inject a fluid onto a subject such as the panel 30. In order to prevent the panel 30 from interfering with the nozzle 52 when the panel 30 is placed from above the table 10, for example, a retraction mechanism that rotates the nozzle 52 in the horizontal direction and retreats from the panel 30 is provided. Alternatively, the nozzle 52 may be disposed upward below the panel 30 so as not to interfere, and the fluid may be ejected from below the panel 30. The nozzle 52 is an example of an adjusting means, is detachably attached, and can be replaced. The fluid may be a gas or a liquid, and examples thereof include easy-to-handle air. The adjusting valve 53 controls the pressure and flow rate of the fluid that is finally ejected from the nozzle 52, thereby adjusting the excitation force and the frequency at which the subject is vibrated and excited.

  The solenoid valve 54 is electromagnetically opened and closed in response to a signal from an external computer 70 or the like, and supplies compressed air to the nozzle 52 continuously or intermittently. As a result, the excitation timing, the excitation time, and the like can be adjusted.

  The tank 55 stores the compressed air provided to the nozzle 52, and suppresses pressure fluctuations when the fluid is ejected. The pressure increasing valve 56 is provided between the supply source 57 and the tank 55, and increases the pressure of the fluid when the pressure of the supply source 57 is lower than a necessary pressure. The supply source 57 is, for example, a compressor and is provided inside or outside the vibration exciter 50 and supplies compressed air to the tank 55.

  The vibrator 50 is set so that the potential core hits the subject. Here, the potential core is a uniform flow region having a certain length, and is indicated by E in FIG. In this region, there is little disturbance and the fluid velocity and fluid pressure are stable. F is a mixing region where the stationary fluid and the outflow gas are mixed, and turbulence occurs due to the shear between the gases. G is a turbulent region where turbulence diffuses throughout. In order to configure the potential core so as to contact the subject, for example, the position adjustment mechanism 58 adjusts the distance x from the nozzle 52 to the subject, and the distance x is about 5 times the diameter D of the nozzle 52. For example, it may be set to be shorter. Further, the nozzle diameter or the like may be set by exchanging 52.

  The sensor unit 60 is detachably attached to the vicinity of the outer periphery of the panel 30 on the opposite side of the vibration exciter 50 with the support region interposed therebetween via an attachment portion 61. That is, the support region is disposed between the sensor unit 60 and the vibration exciter 50. The sensor unit 60 is an example of a vibration detection unit, and includes an acceleration pickup sensor 62 having a spherical magnet 62a at the tip, as shown in FIG. 8, and the spherical magnet 62a comes into contact with the lower surface of the panel 30 to accelerate the sensor. Detect vibrations based on

  The sensor unit 60 is disposed in a portion such as a hole portion such as the window hole 31 where cracks or strains are likely to occur. The sensor unit 60 is configured to be height-adjustable by, for example, a rotary clamp cylinder or the like, and can cope with various shapes of subjects.

  As shown in FIG. 1, a computer 70 is provided outside the table 10 as an example of a quality determination unit. The computer 70 is connected to a filter 80 that removes an unnecessary frequency band vibration waveform from the waveform detected by the sensor unit 60 and increases the signal-to-noise ratio (SNR). The computer 70 includes an AD converter that converts the analog signal filtered by the filter 80 into a digital signal.

  In addition, the computer 70 includes a waveform cutout unit that cuts out a waveform for calculating a feature amount from a digital signal on the output side of the AD converter. This waveform cutout means can simplify the calculation for calculating the feature amount. A filter is connected to the output side of the waveform cutout means. This filter passes only vibrations in the frequency band of vibrations generated from the subject having cracks, strains, and the like. Linear prediction coefficient calculation means is connected to the output side of the filter. The linear prediction coefficient calculation means calculates a linear prediction coefficient that is a feature amount of the signal that has passed through the filter. As a calculation method, for example, there is a method based on the maximum entropy method.

  Here, the linear prediction coefficient is one of the feature quantities used in the signal processing, and can store the signal frequency information in a compressed form. Furthermore, when a spectrum is calculated using a linear prediction coefficient obtained by the maximum entropy method, there is a feature that a highly accurate spectrum can be obtained for temporally short data.

  The output side of the linear prediction coefficient calculation means is connected to a determination unit that determines the quality of the subject. This determination unit is based on the pattern matching method. When the feature value of the panel 30 is input to the boundary learning type neural network constructed by inputting the feature value of the non-defective sample, the difference between the two is set to a predetermined value. Whether or not this value has been reached is output as a pass / fail judgment result. For example, if the difference between the feature value of the panel 30 and the feature value of the non-defective sample is larger than a predetermined value, it is determined as a defective product, and if it is smaller, it is determined as a good product.

  Next, the operation of the press line including the inspection process using the quality inspection apparatus according to the present embodiment will be described. First, as shown in FIG. 9A, a metal plate is formed into a predetermined shape through a pressing process. At this time, for example, a rough shape is formed, followed by edge processing, hole processing, and the like. Thus, the panel 30 is formed and the window hole 31 is formed.

Next, the panel 30 is placed at a predetermined position from above the table 10 by the transporter. At this time, even if there is a slight misalignment, the panel 30 slides from the upper part 42b of the curved part 42 of the guide part 40 to the lower end part 42a and moves to a predetermined position accurately.
The nozzle 52 is disposed at a position retracted from the panel 30. Accordingly, the plurality of support portions 20 come into contact with predetermined positions on the lower surface of the panel 30. After the panel 30 is stabilized in this way, the escape mechanism 43 of the guide portion 40 is operated, and the bending portion 42 moves outward (two-dot chain line in FIG. 5). Thus, the guide part 40 is separated from the panel 30. In this way, the panel 30 is supported by only the tip portions 23 of the three support portions 20.

  Next, the nozzle 52 moves from the retracted position upward near the outer periphery of the panel 30, the shaker 50 is activated, and air is injected onto the panel 30. At this time, the solenoid valve 54 is controlled or set by the external computer 70 so that the injection is performed at a predetermined timing and a predetermined injection period.

  Further, the position adjustment mechanism 58 and the adjustment valve 53 set the distance from the nozzle 52 outlet to the panel 30, the injection angle, and the like by the control of the computer 70 or manually, so that the potential core hits the panel. That is, for example, as described above, the distance x from the injection port of the nozzle 52 to the panel 30 is adjusted to be shorter than 5 times the diameter D of the nozzle 52. Further, the pressure of the compressed air, the ejection speed, and the like are adjusted by a regulating valve or the like, so that the magnitude of vibration and the excitation vibration frequency band of the excited panel 30 are also set within a predetermined range.

  When the panel 30 vibrates due to the jet of air from the shaker 50, the sensor unit 60 detects the vibration. With respect to the vibration waveform detected by the sensor unit 60, the vibration waveform in an unnecessary frequency band is removed by the filter 80. The information on the vibration waveform whose SN ratio is thus increased is sent to the external computer 70.

In the computer 70, an analog signal for the vibration waveform is first converted into a digital signal by an AD converter. Next, the waveform cutout means cuts out a waveform in a certain time band for calculating the feature value from the digital signal.
The waveform thus cut out passes through the filter. The linear prediction coefficient calculation means calculates a linear prediction coefficient that is a feature amount based on the waveform that has passed through the filter. The linear prediction coefficient, which is the feature amount, is input to a boundary learning type neural network constructed by inputting the feature amounts of a plurality of non-defective samples in advance. Then, the determination unit performs pass / fail determination based on the difference between the two. For example, if the difference between the two is larger than a predetermined value, it is determined as a defective product, and if it is smaller, it is determined as a non-defective product.

  The determination result is notified to subsequent processes in synchronization with the movement of the panel 30. That is, for example, the determination result of the corresponding panel 30 is displayed on the monitor 90 in the vicinity of the loading table at the same time when the panel 30 that is the object of the pass / fail determination reaches the loading table. In this way, a recheck is performed by visual inspection of the worker.

  The sensor unit 60, the vibrator 50, the guide, and the support unit 20 are detachable, and the mounting structures of the mounting units 21, 41, 51, and 61 are the same. This inspection is performed in the same manner as described above by using the quality inspection apparatus 1 by changing the positions of the mounting portions 21, 41, 51, 61 in accordance with the shape of the subject.

In addition, the vibration isolation mechanism provided in the table 10 prevents adverse effects caused by external vibrations (for example, vibrations caused by a pressing process disposed in the vicinity).
In the above embodiment, since the fluid potential core is set so as to collide with the subject, accurate and stable vibration can be given and accurate vibration data can be obtained. Therefore, it is possible to detect minute changes in vibration sensitively and detect minute quality differences such as crack signs.

  According to the shaker 50 according to the present embodiment, the taper angle, the diameter, and the jet shape of the nozzle 52 can be adjusted by replacing the nozzle 52, and the pressure of the fluid can be adjusted by the adjusting valve 53 and the pressure increasing valve 56. And the speed can be adjusted. The position adjustment mechanism 58 can adjust the injection angle and the distance between the subject and the injection port, and furthermore, the excitation timing and the excitation time can be adjusted by opening and closing the solenoid valve 54. Therefore, stable vibration can be easily given without being limited to the shape of the subject.

  Since the fluid is jetted onto the subject and vibrated, the subject is not deformed or damaged, and is wider from a low frequency to a high frequency as shown in FIG. It is possible to excite the band, and it becomes easier to capture the characteristics of defective products that occur in various bands. In addition, since it is a continuous excitation, it is possible to collect data according to the purpose by extracting vibration data in an arbitrary time zone.

  By adopting a configuration in which the vibration is applied to the outside of the support region of the panel 30 by the vibration exciter 50, a minute change in vibration can be detected sensitively. That is, when the inside of the support region is vibrated, the vibration is slowed by the support portion 20 and thus the vibration becomes dull. However, according to this configuration, the vibration is not hindered, so that a minute vibration change is accurately detected, and the panel 30 It is also possible to detect sensitively the signs of cracks.

  By adopting a configuration in which a part or all of the support region is located between the vibration exciter 50 and the sensor unit 60, vibration can be effectively transmitted. That is, if the vibration exciter 50 and the sensor unit 60 are provided in the same direction with respect to the support area, vibration cannot be effectively used and it is difficult to accurately detect a minute quality difference. By virtue of being positioned in the opposite direction, it is possible to effectively use vibrations and accurately detect minute quality differences. Since the outer shape of the distal end portion 23 of the support portion 20 has an arc shape in cross section, the contact portion between the distal end portion 23 and the subject can be suppressed to be small and can be fixed without hindering the vibration caused by the vibration exciter 50.

Since the guide unit 40 is separated from the panel 30 after the panel 30 is stabilized at a fixed position and before being vibrated, the vibration by the vibrator 50 is not hindered.
By providing the table 10 having the vibration isolation mechanism, vibration from the outside of the quality inspection apparatus 1 can be reduced and high inspection accuracy can be ensured.

Since the determination result is notified in a separate process in synchronization with the subject movement, a more reliable examination can be performed by performing a double check with reference to the determination result.
Since the vibrator 50, the sensor unit 60, the support unit 20, the guide unit 40, and the like can be attached and detached, a wide variety of members can be inspected by the same quality inspection apparatus 1, and the versatility is high. Therefore, the equipment cost can be reduced.

  When the quality inspection apparatus 1 performs the inspection at a timing that avoids the vibration of the press in the press line, a more accurate and quick inspection can be performed. That is, in a press line having a plurality of press processes and having a press machine that simultaneously performs a molding operation in each press process, timing t1 or t2 that avoids vibration due to the molding operation of the press machine as shown in FIG. Inspect at. In particular, the inspection at the timing of the attenuated t2 can reduce the adverse effects due to the external vibration and can be more reliably inspected than the t1 where the vibration due to the conveyance is not attenuated. Moreover, it is performed smoothly by incorporating it into the press line.

  In the present embodiment, since the panel 30 is vibrated by fluid ejection, a difference at a high frequency can be sensitively detected. That is, as shown in FIG. 12, for example, in the case of vibration by striking (FIG. 12 (a)), the high frequency band A is not vibrated, and when vibrating by sound (FIG. 12 (b)), the high frequency In the band B, the excitation force becomes weaker as the frequency becomes higher. However, in the excitation by fluid injection as in the present embodiment (FIG. 12C), the excitation force is stable in a wide band including the high frequency band C. Is obtained.

  Therefore, the difference appearing in the high frequency band can be sensitively detected. In addition, the configuration in which inspection is performed based on vibration enables a wider range to be inspected than in the case of using a CCD camera as in the prior art. Moreover, installation is facilitated by providing the vibration exciter 50 on the outer periphery, and even minute differences in quality can be sensitively detected by making maximum use of vibration. Furthermore, since the power spectrum can be calculated with a small number of linear prediction coefficients, the number of feature quantities can be reduced as compared with the case where other feature quantities are used.

In carrying out the present invention, the number and shape of each member such as the sensor unit 60, the support unit 20, and the guide unit 40 can be variously changed without departing from the scope of the invention. Needless to say.
In the above embodiment, both the solenoid valve 54 and the regulating valve 53 are used. However, valve operation and pressure control may be unified by using an electropneumatic proportional valve.
Moreover, although the downward straight nozzle 52 is shown, it may be L-shaped or oblique.
Although the case where the three support portions 20 form a triangle in the above embodiment has been described, the number, positions, and support regions of the support portions 20 can be changed as appropriate. For example, when there is one support part, only the contact part becomes a support area, and when there are two support parts, a straight line connecting two support parts becomes a support area. Further, when there are four or more support portions, a polygon formed by the support portions is a support region.

  In the embodiment described above, the quality determination result is displayed on the monitor 90 and notified. However, immediately after the examination is completed, the subject may be notified by marking it with a color, a character, or the like. Moreover, when taking out a product with an automatic machine in the final process, you may set so that a signal etc. may be sent to an automatic machine as a determination result.

Although the tip portion 23 of the support portion 20 is hemispherical and configured to make point contact with the panel 30, the tip portion may be semicircular in the longitudinal section and rectangular in the transverse section, and may be in line contact with the panel 30. In this case, even if the number of support portions 20 is two, it can be stabilized.
Furthermore, the adjustment of the solenoid valve 54 and the nozzle 52 of the vibration exciter 50, the escape mechanism 43 of the guide unit 40, and the retracting mechanism of the nozzle 52 are shown to be controlled by the external computer 70. It may be set in advance to operate at a predetermined interval.

In the above-described embodiment, the configuration in which the panel 30 is placed at a predetermined location on the table 10 by the conveyor is shown. However, the table 10 may be incorporated in the conveyor. For example, as shown in FIG. 9B, the table 10 is attached to the side of the conveyor after the pressing process so that the table 10 can be moved up and down, and the table 10 moves upward when the panel 30 is transported to the conveyor and positioned above the table 10. To be configured. Thereby, the vibration at the time of mounting is suppressed small, and a conveyance machine is also unnecessary.
Although the case where it applied in the press line was shown in the said embodiment, it is applicable not only to this but to the inspection in every scene.

The top view of the quality inspection apparatus concerning embodiment of this invention. The AA arrow line view of FIG. The BB arrow line view of FIG. The front view of the support part concerning embodiment of this invention. The front view of the guide part concerning embodiment of this invention. The front view of the vibration exciter concerning the embodiment of the present invention. Explanatory drawing which shows the structure of the vibration exciter concerning embodiment of this invention. The front view of the sensor concerning the embodiment of the present invention. Explanatory drawing which shows the work process of the press line concerning each embodiment of this invention. Explanatory drawing of a potential core. The figure which shows the stable period in the press line concerning embodiment of this invention. The figure which shows the relationship between an excitation method and a frequency.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Quality inspection apparatus (quality inspection apparatus), 10 ... Table (base), 11 ... Mounting part 20 ... Support part (support means), 30 ... Panel (test object), 40 ... Guide part, 43 ... Escape mechanism 50 ... Vibrator (vibration means), 52 ... nozzle, 58 ... position adjustment mechanism,
60 ... sensor unit (vibration detecting means), 70 ... computer (good / bad determining means).

Claims (3)

A support means for supporting the subject;
Excitation means for causing vibration by causing a fluid to collide with the subject;
Vibration detecting means for detecting vibration of the subject;
A quality inspection apparatus comprising: a quality determination unit that performs quality determination of the subject based on vibration detected by the vibration detection unit;
Adjusting means for adjusting a collision state between the fluid and the subject;
A quality inspection apparatus configured such that a potential core of the fluid collides with the subject.   2. The quality inspection apparatus according to claim 1, wherein the vibration exciter includes a replaceable nozzle, and at least one of a shape of the ejection port, a diameter of the ejection port, and a taper angle of the ejection passage is adjustable. .   The quality inspection apparatus according to claim 1, wherein the vibration exciter includes an adjusting unit that adjusts an injection angle or an injection distance of the fluid.

Images