JPS63115052A - Rotary flaw detector - Google Patents

Abstract

PURPOSE:To improve the accuracy of detection by rotating a rotary detection part along a body to be inspected, and passing a flaw detection signal obtained by a flaw detection probe smoothly to a fixed part side by a rotary transformer. CONSTITUTION:A rotary side coil 28 is wound spirally around the base end of a spindle 20d and a signal line is wired from the flaw detection probe 20a to the coil 28 through a passage 20p. A fixed-side coil 29 is fixed to an outside cylinder 20n through a coil support base 20q and arranged at the outer periphery of the coil 28 while a constant clearance is left. Both coils 28 and 29 constitute the rotary transformer 30 which leads the signal of the probe 20a out to the fixed side. The flaw detection signal from the probe 20a is guided and transmitted to the fixed part by the transformer 30 and passed smoothly, so the flaw detection signal is securely led out, thereby improving the inspection accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a rotary flaw detector configured to rotate along a flange portion in defect inspection of a flange of a can.

[Conventional technology]

In the field of beverage cans, there is a shift from traditional three-piece steel cans to aluminum two-piece cans. This is due to the excellent properties of aluminum, which is particularly good in the field of quality products, its performance as a container such as better sealing performance compared to iron three-piece cans, and the ability to cut can walls extremely thin.
(Draw and Ironinq) It is based on Toshisada's belief that the processing method can significantly reduce material costs. Furthermore, with the recently developed liquid nitrogen filling method, two-piece cans are expanding into fields other than beer and acidic beverages, where three-piece cans have been used exclusively up until now.

As described above, one of the biggest technical problems in the field of two-piece cans, which is growing into a new industrial field, is the processing and handling of the can when wrapping the can lid around the flange of the can to seal the contents. There is a problem when contents leak due to defects in the can flange that sometimes occur. This defect in the flange portion will be briefly explained based on FIGS. 14 to 20.

FIG. 14 shows a part of the new surface of the flange portion of the can, where 1 is the flange portion and 2 is the neck portion.

Defects occurring in this flange portion 1 include flange cracks 3 (see Figure 115), scratches 4 (see Figure 16),
Difference in step 5 (see Figure 17), chip 6 (see Figure 18)
, wrinkles 7 (see FIG. 19), inclusions 8 (see FIG. 20), and irregular molding of the flange.

However, the conventional methods used to inspect cans include applying pressure inside the empty can and observing the decrease in pressure due to leakage from defective parts, and using light (light tester).
etc., and all of these methods have common drawbacks. To explain this, taking as an example a light tester that is widely used in online high-speed inspection, this light tester presses the flange part 1 against the seal rubber 9 and pushes the outside of the can body 10 as shown in FIG. A lamp 11 is used to irradiate light from the flange 1, and a photomultiplier tube 12 is installed outside the flange portion 1. and,
If there is a leakage defect in the can body 10, there will be light leakage, which can be traced by the photomultiplier tube 12 to identify defective cans.

This method works very sensitively in detecting pinholes in the can body and can bottom, but defects in the flange part 1 are closed by being pressed against the seal rubber 9. Only extremely large flange cracks 3 as shown in FIG. 15 can be detected, and other relatively small defects that may cause leakage during seaming cannot be detected.

By the way, with regard to leakage defects in the can body, excluding defects in the flange, advances in can material manufacturing technology and DI processing methods have made the VA degree itself extremely small, and in addition, improvements in the detection performance of light testers have made it possible to reduce leakage defects. There have been no incidents of seed leakage.

On the other hand, regarding defects in the flange, a) 7. Langing itself is a process that easily causes flange cracking, and in order to reduce the cost of containers, the thickness of the can wall is made λ9 and the material is made stronger. This increases the tendency for such defects to occur.

The flange part is easily deformed by contact with objects during transportation and handling of empty cans, and is prone to defects.

c) Conventional detectors have incomplete detection performance due to the reasons mentioned above.

For these reasons, %JLA of two-piece cans has become one of the major technical problems. Moreover, user quality for leakage defects! ! The frequency of occurrence is lpp
It has become a strict requirement of less than m.

Therefore, we de-starred the can flange using eddy current testing.
A test method has been proposed (Japanese Unexamined Patent Publication No. 124-1989)
No. 781, JP-A-55-482, JP-A-57
(Refer to Publication No.-1034).

The principle feature common to these devices is that, as shown in FIGS. 22 and 23, cans 15 supplied from the carry-in chute 13 to the inspection device 114 are held in a can holding section, and the second
In Figure 2, this can 1 is rotated in a certain direction and
When the probe 5 reaches the installation position of the fixed flaw detection probe 16, the can 15 stops its revolution a and rotates in a fixed direction. In this case, in order to detect defects in the flange portion 15a, the flange portion 1
It is necessary to rotate the can 15 until the flaw detection probe 16 installed near the flaw detection probe 16 scans the flange portion 15a at least once. During this period, the orbital movement of the can 15 must be temporarily stopped. Instead, it becomes an intermittent orbital movement. Furthermore, cans 15 that are determined to be defective through the inspection by this flaw detection probe 16 are discharged in the direction, and the food cans are transported to the next process through a carry-out chute 17.

In the above-mentioned conventional inspection device, the accuracy and stability of its defect detection depends on the distance d between the flaw detection probe 16 and the flange portion 15a of the can 15 and the relative positional relationship vertically and horizontally, as shown in FIG. Dependent. That is, in order to obtain stable defect detection performance with higher accuracy, it is necessary that the above-mentioned relative positional relationship be at an optimal position and not fluctuate as much as possible.

However, the conventional cans that rotate on their own axis have the following problems.

1) A slight distortion or variation in dimensions of the can itself causes the flange portion of the can to wobble during rotation, and the relative position with the flaw detection probe 16 tends to fluctuate, reducing inspection accuracy.

2) The wobbling of the rotational motion of the can itself causes fluctuations in the relative position n between the flaw detection probe and the 7-lunge portion, which deteriorates the inspection accuracy.

3) When the can is driven to rotate, the spinner or belt is brought into contact with the thinnest can body, so the can body is susceptible to damage such as dents and scratches.

4) The revolution of the can must be stopped when a defect is detected, resulting in intermittent revolution, which limits the inspection speed and makes it impossible to perform high-speed online inspection with a single machine.

Therefore, when using this type of inspection machine to perform online inspection of a high-speed can manufacturing line, it is necessary to install many inspection machines in parallel, which requires a large amount of equipment cost and installation space. .

Therefore, the present inventors devised a new can flange defect inspection device to solve the above problems.

In this defect inspection device, a rotating probe unit moves in synchronization with the flange of a can that is held by a color revolution mechanism and rotates, and also rotates along the flange. The probe unit inspects the 7 flange portions of the can for defects, the 711 separate circuit determines whether there is a defect in the flange portion, and the removal mechanism removes cans that are determined to have a defect in the flange portion. In this rotary probe unit, it is necessary that the flaw detection probe A-7 be fixed to the flange portion of the can, rotate smoothly, and reliably extract the flaw detection signal detected at the rotating portion.

The present invention has been made in view of the above circumstances, and its purpose is to reliably and smoothly extract the flaw detection signal q detected by the flaw detection probe, and to improve the inspection accuracy. The purpose is to provide a rotating type flaw detection device Ft that can be used.

[Means for solving problems]

In order to achieve the above object, the present invention provides a rotation detecting section that is rotatably provided on a fixed section with a flaw detection probe that detects defects in an object to be inspected, and also fixes signals from this flaw detection probe. A rotary transformer that conducts induction transmission without contacting the fixed part and the rotation detecting part is disposed facing the fixed part and the rotation detecting part.

[For production]

In the rotary flaw detection device of the present invention, the rotation detecting section is rotated along the object to be inspected, the object to be inspected is inspected by the flaw detection probe, and the obtained flaw detection signal is transmitted to the fixed part side by the rotary transformer. Pass the call smoothly.

[Example] Hereinafter, the present invention will be explained in detail based on FIGS. 1 to 13.

1 and 2 show an example of a rotary flaw detection device of the present invention, with FIG. 1 being a front view and FIG. 2 being a side view. The rotary flaw detector 120 is incorporated into a can flange defect inspection apparatus shown in FIGS. 7 and 8.

That is, the rotary flaw detection device 20 has a rotatable main
Twelve pieces are arranged at equal intervals on the outer periphery of the disk 22 fixed to the disk 21.

As shown in FIGS. 1 and 2, the rotary flaw detection device 20 has a self-comparison type eddy current flaw detection probe a-120a fitted into a hole in a light metal block 20b and fixed with a screw 20G. This block 20b is attached to the tip of the spindle 20d. A timing pulley 20e is attached to the tip of the spindle 20d, and the timing pulley 20e is
As shown in FIG. 7, the fixed part 2
The flaw detection probe 20a is connected to a timing pulley 25 on the 4 and a timing pulley 27 attached to the rotating shaft of a motor 26.
It rotates around the axis of the spindle 20d. Further, two bearings 20f are attached to the spindle 20d, and these bearings 20f are connected to a seal collar 200 and a spindle collar 20.
h1 bearing presser 200. The spindle 20d is rotatably supported by the bearing case 20m by being tightened by the bearing nut and washer 20J via the outer ring retaining collar 20j1 and the inner race retaining collar 20k. The bearing case 20m and the bearing holder 201 are fixed to the outer cylinder 2On with screws. Furthermore, the bearing section with the above structure uses a lubrication method in which grease is sealed with a grease seal, and is designed to withstand high-speed rotation. Furthermore, a rotating coil 28 is spirally wound around the base end of the spindle 20d in the longitudinal direction of the spindle 20d.
A signal line is wired to this rotating coil 28 from the flaw detection probe 20a through a passage 2C1 in the spindle 2Od.

A stationary coil 29 is disposed on the outer circumferential side of the rotating coil 28 while being fixed to the outer cylinder 2On via a coil support 20Q, with a constant clearance between the two coils. 28 and 29 constitute a rotary transformer 30 that extracts the signal from the flaw detection probe 20a to the fixed side.

In addition, 2Or in the figure is an adjuster screwed into the middle part of the outer cylinder 2On in order to adjust the clearance between the can flange part and the flaw detection probe 20a to a constant level when the rotary flaw detection device 20 is attached to the disk 22. 206 is a rear cap for enclosing and protecting the rotary transformer 30. Further, the eddy current flaw detection probe 20a detects a change in the high frequency input signal due to a change in impedance due to a crack in the object to be inspected (flange portion of a can) or the like.

The main @21 is powered by the motor 32 on the pedestal 31.
Timing pulley 33, 34, timing belt 35,
It is designed to be rotated via a reduction gear 36. This main shaft 21 has a main Irl1! A disk 38 for holding the can bottom and a star wheel 39 for holding the can II are respectively fixed between the fixed plate 37 that rotatably supports the can 21 and the disk 22. Twelve can bottom holders 40 are attached to the outer periphery of the disk 38 so as to be retractable from the star wheel 39 side, facing each of the rotary flaw detection devices 20. It is designed to hold the bottom of the can by suction. As shown in FIGS. 5 and 6, each can bottom holding stand 40 is
*An L-shaped mounting member 40b fixed to the base end of the mounting member 40a, a cam follower 40C rotatably mounted to one end of this mounting member 40b, and a cam follower 40C mounted on the support shaft 40a, with the mounting member 40b leftward. a guide member 40f fixed to the disk 38 and having a U-shaped groove 40e; and a groove 4Qe of the guide member 40f rotatably attached to the other end of the mounting member 40b. The cam follower 40C contacts the arc-shaped cam 41 attached to the stationary plate 37 facing the disc 38, and thereby the can bottom holding stand 40 protrudes toward the star wheel 39 side, facing the spring 40d.

Further, the star wheel 39 is connected to the can bottom holding base 40.
A can body holding part 39a made of nylon resin is arranged opposite to the can body holding part 39a, and this can body holding part 39a has a predetermined angle α.
Infeed chute 4 feeding cans 15 at an angle
2 (see Fig. 7), a corrugated recess corresponding to the diameter of the can is formed so that the can 15 can be snatched away at high speed. The function is to blow away the can 15 that has been determined to be .

Twelve head amplifiers 43 are fixed in the circle 'm22. And these head amplifiers 43 have
Electric power is supplied through a slip ring 44 fixed to the main shaft 21 and a slider 46 fixed to a fixed member 45. Further, in FIG. 8, a Mercury slip ring 48 is connected to the tip of the main shaft 21 protruding from the bearing case 47 via a coupling 49. Further, a timing pulley 53 attached to the rotating shaft of an absolute rotation enhancer 52 is connected to a timing pulley 50 attached to the tip of the main shaft 21 via a timing belt 51. And 1
The two can holders (stations) are sequentially numbered 1 to 12 to 5.
The 4-bit signals of the rotary encoder 52 are used to identify the numbers of these numbered stations. Furthermore, in FIG. 7, below the infeed chute 42, there is a Dimechi 1? - The shoot 54 is arranged to be inclined at a predetermined angle β. Note that the rotation speed of the flaw detection probe 20a by the motor 26 is configured to vary depending on the rotation speed (revolution speed) of the main shaft 21. In other words, as the revolution speed increases, the time that can be inspected for one can flange becomes shorter.
The rotational speed of the flaw detection probe 20a is increased so that it can scan at least one round or more of the can flange.

Each of the head amplifiers 43 has a bridge circuit, and performs signal 1 processing that amplifies the flaw detection signal from each of the rotary flaw detection devices 20 and converts the signal to a lower frequency of about 1/4 of the detection frequency. This improves mutual induction shielding in crowded signal post-processing processes, prevents crosstalk, and eliminates the need to use commercial quality cables for signal transmission. . moreover,
These head amplifiers 43 are small and lightweight in order to be attached to a rotating body, and are configured to be able to absorb the centrifugal force caused by high-speed orbital motion. The signals processed by these head amplifiers 43 are then transmitted to a time division multiplex circuit 55 attached to the same rotating body section A as the head amplifier 43, as shown in FIG. ing. This time-division multiplexing circuit 55 is configured such that the next signal transmission path, the marked Lee lip ring 48, cannot be made into multiple poles, and the time for defect detection by the rotary flaw detection device 20 is limited. Time division multiplex reception circuit 5
6. A synchronization pulse output from a synchronization pulse generation circuit 57 is input to the time division multiplex reception circuit 56 based on a 4-bit pulse signal (see FIG. 9) from the rotary encoder 52. As shown in Fig. 10, this synchronization pulse is a signal for specifying the time for flaw detection on the can flange at each station (can holder), corresponding to each station number. For example, the synchronization pulses between station numbers 1 and 2 overlap by 172 pulse widths. Also, adjacent odd numbers or even numbers, for example,
A slight time interval is provided between the falling edges and rising edges of synchronization pulses No. 1 and No. 3, and No. 2 and No. 4, in order to avoid interference. The synchronizing pulses inputted to the time division multiplex receiving circuit 56 are
The signal is returned to a bit pulse train number and sent via the Mercury slip ring 48 to the time division multiplexing circuit 55, where it is again converted into a synchronizing pulse specifying each station as shown in FIG. . As a result, based on the synchronization pulse, the time division multiplexing circuit 55 sequentially transmits the flaw detection signals from the specified odd-numbered head amplifiers 43 and the flaw detection signals from the even-numbered head amplifiers 43 through the Mercury slip ring 48. to the time division multiplex reception circuit 56, and the time division multiplex reception circuit 5
6 is configured to sequentially distribute the odd-numbered flaw detection signals and (1-numbered flaw detection signals) to the twelve defect signal acquisition circuits 58, respectively.

Furthermore, the pulse train shown at the top of FIG. 9 is inputted to each of the defect signal acquisition circuits 58 from the time division multiplex reception circuit 56. These defect signal acquisition circuits 58 perform cosine function analysis and bandpass filter processing on the above-mentioned flaw detection signals in an absolute blog manner to extract defect signals.
The pulse train signal shown at the top of FIG. 9 above automatically controls the transmission frequency band of the bandpass filter to remove the noise component of the probe signal. Here, the reason why the transmission frequency band of the bandpass filter is controlled is that the rotation speed of the flaw detection probe 20a is
Since the configuration changes according to the rotation speed of the
This is because the flaw detection signal detected by the second probe 20a is also affected by the change in the rotation speed of the main @ 21, so it is necessary to correct this.

Further, the defect signals extracted by each of the defect signal sampling circuits 58 are displayed on a signal monitor 59 and are also inputted to a discrimination circuit 61 via an OR circuit 62. Further, the output signals from each of the rotary flaw detection devices 20 are sent to the head amplifier 43, the time division multiplex circuit 55, the Mercury slip ring 48, the time division multiplex reception circuit 5,
6. The signal passes through the defect signal collection circuit 58 and is manually inputted to the self-diagnosis circuit 60, and this self-diagnosis circuit 60
By monitoring the voltage of each of the above output signals, 1'
? , when normal voltage occurs, an alarm signal is sent to 71 separate circuit 6
It is designed to output for 1.

Then, the discrimination circuit 61 selects [Registered defect signal acquisition circuit 5
When the voltage of the defect signal extracted by 8 exceeds a predetermined value, a command signal is output to a sequencer (not shown) to cause the defective can to be discharged. difference"
Furthermore, this discrimination circuit 61 is similar to the self-diagnosis circuit 60.
Based on the alarm signal, the station number of the malfunctioning station is displayed, as well as whether defective cans have been discharged or not, or the number of defective cans to be removed for each station is displayed.

Next, the flange portion 15a of the can 15 is inspected using a defect inspection device incorporating the rotary flaw detection device configured as described above.
We will explain the case of inspecting.

First, by driving the motor 32, the timing pulleys 33, 34, the timing belt 35, and the reducer 3
6, the main shaft 21 is rotated. As a result, the pair of discs 22, 38 and the star wheel 39 fixed to the main shaft 21 rotate together with the main shaft 21. Along with this,
By driving the motor 26, the flat belt 23, which is stretched across the timing pulleys 25 and 27, is prevented from rotating.

As a result, the timing pulleys 20e of the several rotary probes 20 that are in contact with the flat belt 23 rotate, and the flaw detection probe 20a rotates together with the spindle 20d.

In this state, when cans 15 are continuously fed from the infeed chute 42, these cans 15 are sequentially stored in the recess of the can body holding portion 39a of the rotating (revolving) star wheel 39. , rotates together with the star wheel 39. In this case, the can body of the can 15 housed in the recess is suctioned by a vacuum, and the can bottom is suctioned by a vacuum to the can bottom holder 40, so that centrifugal force is avoided during high-speed continuous rotation. Not only will it not be blown away, but it will also be accurately positioned with respect to the flaw detection blow 120a.

Next, as the cam follower 40G comes into contact with the cam 41, the can 15 approaches the rotary flaw detector 20, and when the can 15 approaches the closest, the flaw detection probe 20a of the rotary flaw detector 20 touches the flange of the can 15. The flange at 15 a is inspected for defects by rotating at least once along the flange at 15 a. The detection signal detected by the flaw detection probe 20a is sent to the head amplifier 43 via the rotary transformer 30, and after signal processing, is sent to the fixed side via the time division multiplexing circuit 55 and the Mayanili slip ring 48. control box B
The signal is sent to the time-division multiplex reception circuit 56 in the internal circuit, and is then sent to the determination circuit 61 via each defect signal acquisition circuit 58 to determine whether it is a defective can or a food can.

On the other hand, the can 15 is being rotated while being suctioned and fixed by the can body holding part 39a of the star wheel 39 and the can bottom holding base 40.
After the inspection by the flaw detection probe 20a, the suction of the can bottom is stopped, the amount of protrusion of the cam 41 toward the star wheel 39 is reduced, and the can bottom holding base 40 is separated from the star wheel 39. Since the can 15 is separated from the bottom holding base 40 and the interval between rain sounds becomes larger, the discharge of the can 15 (in case of a defective can) and the discharge chute 54
(in the case of food cans) can be easily delivered.

In the above embodiment, as the rotary transformer 30, the cylindrical stationary coil 2, which is also spirally wound, is placed around the outer periphery of the cylindrical rotating coil 28, which is also spirally wound.
9 is arranged, but as shown in FIG. 12 and FIG. Alternatively, the fixed coil 73 may be spirally wound.

(Effects of the Invention) As described above, the present invention includes a rotation detecting section that is rotatably provided on a fixed section, and a flaw detection probe for detecting defects in an object to be inspected, and a signal from the flaw detection probe. A rotary transformer that inductively transmits the information to the fixed part without contact is placed facing between the fixed part and the rotation detecting part, so the rotation detecting part is rotated along the object to be inspected and the flaw detection probe detects the object to be inspected. By inspecting the body and smoothly passing the obtained probe signal to the fixed part using a rotating transformer, the flaw detection signal detected by the flaw detection probe can be reliably extracted, improving inspection accuracy and This has the excellent effect of increasing the speed of inspection.

[Brief explanation of the drawing]

1 to 11 show an embodiment of the present invention, in which FIG. Figure 5 is a front view of the can bottom holder, Figure 6 is a side view of the same, Figure 7 is a side view of the defect inspection device, Figure 8 is a front view of the same, Figure 9 is the output of the rotation 1 encoder. FIG. 10 is an output waveform diagram of the cyclic pulse generation circuit, FIG. 11 is a block diagram of the electric circuit, and FIGS. 12 and 13 show other examples of the rotary transformer. The figure is a schematic configuration diagram, Figure 13 is a cross-sectional view,
Figure 4 is a sectional view of the can, Figures 15 to 20 show examples of defects in the can flange, Figure 15 is an illustration of a 7-lunge crack, Figure 16 is an illustration of a scratch, and Figure 17 is an illustration of a crack. 18th F4 is an explanatory diagram of the difference in steps, 18th F4 is an explanatory diagram of the chipped part, 19th
Figure 20 is an explanatory diagram of included inclusions, Figure 21 is an explanatory diagram of the principle of a conventional light tester,
FIG. 22 is an explanatory diagram of a conventional can flange inspection device, and FIG. 23 is an explanatory diagram of an inspection unit equipped with the same. 15... Can, 15a... Flange part,
20... Rotating type flaw detection device, 28... Rotating side coil, 29... Stationary side coil, 30...
-... Rotating transformer, 72... Rotating side coil, 73... Fixed side coil, 20a...
Eddy current flaw detection probe, 2Of...Bearing,
20n... Outer cylinder.

Claims (1)

[Claims] A rotation detection section is rotatably provided on the fixed part, and a flaw detection probe for detecting defects in the object to be inspected is provided on the rotation detection part, and a signal from the flaw detection probe is guided to the fixed part without contact. A rotary flaw detection device characterized in that a transmitting rotary transformer is disposed facing between the fixed part and the rotation detecting part.