JP4670148B2 - Screw part eddy current inspection probe and holding device for the probe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a screw part eddy current inspection probe for use in an eddy current flaw inspection of an internal thread (inner thread) formed inside a shaft or the like, and a holding device for the probe.
[0002]
[Prior art]
For example, although a female screw is formed at the center of the shaft of the compressor disk, the compressor disk is rotated at a high speed, so that a large stress acting during rotation may cause cracks in the female screw. . Thus, when a crack occurs in the female thread, it is desired to detect the crack early by conducting an inspection by periodic inspection or the like so that the crack does not grow and cause a serious problem.
[0003]
By the way, as one of non-destructive inspections performed to detect a defect such as a crack generated in a component, an eddy current inspection probe having a flaw detection coil is brought close to a conductive sample to be inspected. Eddy currents are induced and generated in the inspection object by approaching the flaw detection coil. In this case, if the inspection object has a defective part, the eddy current generated when the flaw detection coil approaches the defective part. Therefore, there is an eddy current flaw inspection in which the presence or absence of a defective portion in the inspection object can be inspected by detecting the fluctuation of the eddy current.
[0004]
[Problems to be solved by the invention]
However, in order to carry out the eddy current flaw inspection, it is necessary to bring the flaw detection coil close to all parts where the occurrence of the defective portion is a concern. Conventionally, in order to carry out the eddy current flaw inspection with the female screw as the inspection object. No eddy current inspection probe, that is, an eddy current inspection probe capable of inserting the flaw detection coil inside the female screw and allowing the flaw detection coil to approach the entire inner peripheral surface of the female screw efficiently has been proposed. Therefore, the actual situation is that the eddy current flaw inspection of the female screw has not been carried out.
[0005]
Therefore, the present invention can perform the eddy current inspection by efficiently approaching the flaw detection coil over the entire inner peripheral surface of the female screw, and when there is a defective portion, the detection can be reliably performed. An object of the present invention is to provide a screw part eddy current inspection probe and a holding device for the probe.
[0006]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention includes an external male threaded portion that can be screwed into a female screw to be inspected on the distal end side of the probe body, and a circumferential direction at the distal end of the male threaded portion. A screw portion eddy current inspection probe having a configuration in which a flaw detection coil is embedded in one place is provided.
[0007]
When performing an eddy current flaw inspection, the male screw portion is gradually screwed into the female screw to be inspected. When there is a defect such as a crack in the female screw to be inspected, the flaw detection coil at the front end of the male screw part is reliably brought close to the defect part as the male screw part is screwed in. Based on this, the presence of a defective part is detected.
[0008]
In addition, a slide bar extending in the axial direction is slidably provided on one side in the circumferential direction of the probe barrel corresponding to the installation position of the flaw detection coil, and the tip of the slide bar is a male screw part to be inspected. Coil position that allows it to abut against the end face of the female screw when screwed into the female screw, and to display the amount of penetration of the flaw detection coil into the female screw by the amount of slide from the side of the flaw detection coil at the tip of the slide bar By adopting a configuration including a display device, position information regarding the circumferential direction of the flaw detection coil can be obtained from the position of the slide bar with respect to the circumferential direction of the probe body, and the inspection target of the flaw detection coil can be obtained from the slide amount of the slide bar. Information about the amount of penetration into the internal thread can be obtained, and for this reason, the circumferential direction of the probe body at the time when the defective part is detected during the eddy current inspection Position of the slide bar against, and, based on the amount of sliding of the slide bar, it is possible to obtain position information of the defective portion.
[0009]
Furthermore, a rotation mechanism comprising a base member for fixing at a required position, a shaft extending in the vertical direction, and a cylindrical portion rotatably attached to the outer periphery of the shaft, a guide rail extending in the vertical direction, , the guide rail comprising a slidably mounted a guide block lifting mechanism, and, by interposing an elastic mechanism which enables stretch horizontally sequentially insulator made capable screwed with the internal thread be tested A screw part eddy current inspection probe having a configuration in which a male screw part is provided on the tip end side of the probe body part and a flaw detection coil is embedded in one circumferential direction at the tip part of the male screw part is grasped vertically downward. If the holding device for the screw part eddy current inspection probe has a configuration in which the screw device is connected, the screw part eddy current inspection probe can be securely held vertically downward by holding it with the gripper. In addition, a two-dimensional horizontal direction of the eddy current inspection probe for the screw part gripped by the gripper is combined by combining horizontal swinging about the axis of the swinging mechanism and horizontal linear movement by the telescopic mechanism. When the object having the female screw to be inspected is rotated at a constant speed on the turntable, even if the female screw rotates eccentrically, the eccentricity is absorbed and used for the screw part. The eddy current flaw detection inspection can be continuously performed while following the eddy current inspection probe, so that the reliability of the inspection can be improved, and the male screw portion of the eddy current inspection probe can be screwed into the female screw to be inspected. The work can be automated, the labor of the inspector during the inspection can be eliminated, and the inspection man-hours can be reduced.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0011]
1 (a), (b), and (c) show one embodiment of the eddy current inspection probe for a threaded portion of the present invention, and a cylindrical probe body 1 with a distal end portion (lower end portion in the figure) closed. One end surface (upper end surface) of an insulating male screw portion 2 disposed on the same axis is attached to the tip end surface of each of the two, and the male screw portion 2 is formed at, for example, the central portion of the shaft of the compressor disk. The flaw detection coil is formed in a shape that can be screwed with a female screw to be inspected, such as a female screw, and is provided at one end in the circumferential direction at the tip of the male screw portion 2, for example, the top of the screw thread 3 that is the second pitch. 4 is embedded.
[0012]
The other end of the signal cord 5 having a connector 6 at one end is connected to the flaw detection coil 4 by being guided from the rear end side of the probe barrel portion 1 through the inside of the barrel portion 1 and the male screw portion 2, and the connector 6 Is connected to an eddy current flaw inspection apparatus (not shown) directly or with another signal cord interposed, so that a signal generated by the flaw detection coil 4 is sent to the eddy current flaw inspection apparatus via the signal cord 5 and the connector 6. I can do it.
[0013]
Further, a coil position display device 7 is provided on one side in the circumferential direction of the probe body 1 corresponding to the circumferential position of the flaw detection coil 4 with respect to the male thread 2, and the male thread 2 is screwed into the female thread to be inspected. In this case, the position of the flaw detection coil 4 in the circumferential direction is indicated, and how much the flaw detection coil 4 is located from the end face of the female screw is indicated.
[0014]
The coil position display device 7 is provided with a guide groove 8 extending in the axial direction on the outer side surface of one side portion of the probe body 1, and a slide bar 9 is slidably fitted in the guide groove 8, The slide bar 9 can be held by the mounting member 10 from the outside, and the slide bar 9 is bent outward at the side position of the flaw detection coil 4 and the rear end protrudes rearward from the probe body 1. The protrusion 11 is provided with a protrusion 11 protruding toward the probe body 1 at the rear end position of the probe body 1, and the protrusion 11 and the inner peripheral surface of the probe body 1 at a required position. As shown in FIG. 1 (a), the protrusion 12 provided so as to face the protrusion 11 is connected to the protrusion 12 by a spring 13 in which a tension acts in the contraction direction. The tip of the slide bar 9 is flawed by tension. On the other hand, when the male screw portion 2 is screwed into the female screw 14 to be inspected as shown by a two-dot chain line in FIG. When 4 reaches the end face level of the internal thread 14, the end of the slide bar 9 comes into contact with the end face of the internal thread 14, and the external thread portion 2 is further screwed in, so that the slide bar 9 is pushed by the end face of the internal thread 14. In this case, the amount of penetration of the flaw detection coil 4 into the female screw 14 is determined by the amount of slide of the slide bar 9.
[0015]
15 is a scale provided along the guide groove 8, and 16 is a marking provided at a required position of the slide bar 9 so that the scale 15 can easily indicate the slide amount of the slide bar 9.
[0016]
When using the eddy current inspection probe for a screw part according to the present invention, first, the probe body 1 is connected in a state where the connector 6 of the signal cord 5 is connected to an eddy current flaw inspection apparatus (not shown) directly or via another signal cord. The male screw portion 2 is gradually screwed into the female screw 14 to be inspected.
[0017]
When a defect portion such as a crack exists in the female screw 14, the eddy current flaw inspection apparatus uses a signal from the flaw detection coil 4 when the flaw detection coil 4 provided at the tip of the male screw portion 2 reaches the position of the defect portion. The presence of a defect is detected. At this time, the position information in the circumferential direction of the defective portion with respect to the female screw 14 is obtained from the circumferential position of the slide bar 9 of the coil position display device 7, and the marking 16 on the scale 15 is obtained. Since the slide amount of the slide bar 9 is indicated by the displacement of the position, information on the depth position of the defective portion from the end face of the female screw 14 can be obtained.
[0018]
As described above, since the flaw detection coil 4 is provided at the tip of the male screw portion 2 having a shape that can be screwed into the female screw 14 to be inspected, the flaw detection coil 4 is configured to screw the male screw portion 2 into the female screw 14. The inner peripheral surface of the female screw 14 can be efficiently scanned over the entire surface. For this reason, the flaw detection coil 4 can be reliably brought close to the defective portion wherever there is a defective portion of the female screw 14, The detection can be performed reliably.
[0019]
Next, FIG. 2 to FIG. 4 show an embodiment of the holding device for the eddy current inspection probe for threaded portion according to the present invention. The base member 17 which can be fixed by a fixing device (not shown) such as a clamp is shown. An upper end of a shaft 19 of a rotating mechanism 18 in which a cylindrical portion 20 is rotatably attached in a horizontal direction to an outer periphery of a vertically extending shaft 19 is connected to the lower end portion, and the cylindrical portion of the rotating mechanism 18 is connected. A rear side of a frame 23 provided with a guide rail 22 such as an LM guide extending in the vertical direction on the front side is attached to a side portion of 20 and a guide block 24 is attached to the guide rail 22 so as to be slidable in the vertical direction. 21, a guide cylinder 26 that extends in the horizontal direction and has a rear end attached to the connecting member 35, and a rod 27 that is slidably inserted into the guide cylinder 26 from one end (front end) side and held. Equipped The connecting member 35 of the expansion / contraction mechanism 25 that can be expanded and contracted in the horizontal direction is connected to the front side of the guide block 24 of the elevating mechanism 21, and is further connected to the tip of the rod 27 of the expansion / contraction mechanism 25 as shown in FIG. (A) (B) A fixed arm 29 of a gripper 28 for gripping the eddy current inspection probe I for screw portion having the same configuration as that shown in (C) is attached.
[0020]
As shown in FIGS. 2 and 3, the gripper 28 has a semicircular fixed arm 29 that is curved in a horizontal direction with a curvature along the outer periphery of the probe body 1 of the eddy current inspection probe I. A quarter-circular movable arm 30 having the same curvature is attached to both ends of the movable arm 30 so as to be rotatable in the horizontal direction via pins 31, respectively, and is further extended in the horizontal direction at the tip of one movable arm 30. A base end portion of a bolt 32 is attached, and the bolt 32 has a distal end side penetrated through a hole 33 formed in the distal end portion of the other movable arm 30 and a wing nut 34 is screwed to the distal end portion. By inserting the probe body 1 of the eddy current inspection probe I into the annular structure formed by the fixed arm 29 and both movable arms 30 with the wing nut 34 loosened, the wing nut 34 is tightened. Are also available detachably gripping the eddy current testing probe I vertically downward.
[0021]
36 is a bearing interposed between the shaft 19 and the cylindrical portion 20 in the rotation mechanism 18, 37 is a linear bush interposed between the guide cylinder 26 and the rod 27 in the expansion / contraction mechanism 25, and 38 is the above-mentioned. The retaining members that prevent the rod 27 from falling off are shown.
[0022]
FIG. 4 shows a use state of the holding device, and shows a case where, for example, an eddy current flaw inspection of the female screw 14 formed at the central portion of the shaft 40 of the compressor disk 39 is performed as an inspection object.
[0023]
When performing the eddy current flaw inspection, first, the compressor disk 39 is placed on the turntable 41 so that the female screw 14 is located at the center of the turntable 41, and the vortex flaw detection inspection is performed on the gripper 28 of the holding device. 1 (a), (b), and (c), a screw part eddy current inspection probe I similar to that shown in FIG. 1 is held downward in the vertical direction, and the male screw part 2 of the eddy current inspection probe I is positioned immediately above the female screw 14. The base member 17 of the holding device is fixed by a fixing device (not shown) at a required position above the turntable 41 so as to be disposed at the position. At this time, the signal code 5 of the eddy current inspection probe I is connected to an unillustrated eddy current inspection apparatus.
[0024]
When the turntable 41 is rotated at a constant speed in the screwing direction of the male screw portion 2 and the female screw 14 in this state, the male screw portion 2 is screwed into the female screw 14, and as a result, as shown in FIGS. In the same manner as described above, the eddy current flaw inspection is performed on the inner peripheral portion of the female screw 14. At this time, if the axial center position of the female screw 14 is slightly deviated from the rotation center of the turntable 41, whirling occurs in the rotation of the female screw 14, but the eddy current gripped by the gripper 28. The inspection probe I has a two-dimensional horizontal direction by combining horizontal rotation about the shaft 19 by the rotation mechanism 18 of the holding device and horizontal expansion / contraction by the expansion / contraction mechanism 25, that is, linear movement. Therefore, even if the internal runout of the female screw 14 is caused to move, the movement can be followed and the eddy current inspection is not hindered.
[0025]
Thus, by using the holding device of the present invention, the eddy current inspection probe I can be easily installed vertically downward by gripping the gripper 28, and the female screw to be inspected using the turntable 41. Since the eddy current flaw inspection can be carried out with the 14 rotating at a constant speed, the reliability of the inspection can be improved, and the male screw portion 2 of the eddy current inspection probe I can be screwed into the female screw 14. The work can be automated, the labor of the inspector during the inspection can be made unnecessary, and the inspection man-hours can be reduced.
[0026]
In addition, this invention is not limited only to the said embodiment, The external thread part 2 of the eddy current inspection probe for thread parts shown to FIG. 1 (A) (B) (C) is the internal thread 14 used as test object. The length and thickness may be freely set according to the size of the probe body, and the probe body 1 is preferably cylindrical, but may be a rectangular tube. In FIGS. 2 and 3, Although the gripper 28 is shown as an annular one provided with movable arms 30 at both ends of the fixed arm 29 so as to be rotatable, if the eddy current inspection probe I can be fixed vertically downward, a clamp type, etc. As an inspection target, an internal thread 14 formed at the center of the shaft 40 of the compressor disk 39 is illustrated as an inspection target. flaw The 査 can be inspected every female screw desired, other, can of course be modified in various ways without departing from the gist of the present invention.
[0027]
【The invention's effect】
As described above, according to the screw portion eddy current inspection probe of the present invention, the distal end side of the probe body portion is provided with the male screw portion made of an insulator that can be screwed with the female screw to be inspected, and the male screw portion. Since the flaw detection coil is embedded in one place in the circumferential direction at the tip, when performing the eddy current flaw inspection, the screw part eddy current inspection probe of the present invention is connected to the eddy current flaw detection device. In this case, by gradually screwing the male screw part into the female screw part to be inspected, the inner peripheral surface of the female screw can be efficiently scanned over the entire surface by the flaw detection coil. As the male screw part is screwed in, the flaw detection coil embedded in the tip of the male screw part is surely brought close to the defective part, so that the eddy current flaw detection apparatus is based on the signal from the flaw detection coil. It is possible to reliably detect the presence of a defective part, and a slide bar extending in the axial direction is slidable on one side in the circumferential direction of the probe body corresponding to the installation position of the flaw detection coil. And when the male screw part is screwed into the female screw to be inspected, the slide bar tip part abuts against the end face of the female screw, and the slide bar tip part slides from the flaw detection coil side position. Accordingly, the position information on the circumferential direction of the flaw detection coil is determined by the position of the slide bar with respect to the circumferential direction of the probe body by providing the coil position display device that can display the amount of penetration of the flaw detection coil into the female screw. In addition, information on the amount of penetration of the flaw detection coil into the female screw to be inspected can be obtained from the slide amount of the slide bar. The position of the slide bar relative to the circumferential direction of the probe body portion at the time when the defect is detected during the inspection, and, based on the amount of sliding of the slide bar, is effective in that it is possible to obtain position information of the defective portion. Furthermore, a rotation mechanism comprising a base member for fixing at a required position, a shaft extending in the vertical direction, and a cylindrical portion rotatably attached to the outer periphery of the shaft, a guide rail extending in the vertical direction, , the guide rail comprising a slidably mounted a guide block lifting mechanism, and, by interposing an elastic mechanism which enables stretch horizontally sequentially insulator made capable screwed with the internal thread be tested A screw part eddy current inspection probe having a configuration in which a male screw part is provided on the tip end side of the probe body part and a flaw detection coil is embedded in one circumferential direction at the tip part of the male screw part is grasped vertically downward. If the holding device for the screw part eddy current inspection probe has a configuration in which the screw device is connected, the screw part eddy current inspection probe can be securely held vertically downward by holding it with the gripper. In addition, a two-dimensional horizontal direction of the eddy current inspection probe for the screw part gripped by the gripper is combined by combining horizontal swinging about the axis of the swinging mechanism and horizontal linear movement by the telescopic mechanism. When the object having the female screw to be inspected is rotated at a constant speed on the turntable, even if the female screw rotates eccentrically, the eccentricity is absorbed and used for the screw part. The eddy current flaw detection inspection can be continuously performed while following the eddy current inspection probe, so that the reliability of the inspection can be improved, and the male screw portion of the eddy current inspection probe can be screwed into the female screw to be inspected. It is possible to automate the work, eliminate the need for inspectors during the inspection, and reduce the number of inspection steps.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows an embodiment of a screw part eddy current inspection probe according to the present invention, in which (A) is a schematic side view, (B) is a view taken in the direction of arrows A-A in (A), and (C). (A) is an enlarged cross-sectional view of a B portion.
FIG. 2 is a schematic side view showing an embodiment of a holding device for a screw portion eddy current inspection probe according to the present invention.
FIG. 3 is a schematic plan view of the holding device of FIG. 2;
4 is a schematic side view showing a use state of the holding device of FIG. 2; FIG.
[Explanation of symbols]
I vortex inspection probe 1 for screw part probe body part 2 male screw part 4 flaw detection coil 7 coil position display device 9 slide bar 14 female screw 17 base member 18 rotating mechanism 19 shaft 20 cylindrical part 21 lifting mechanism 22 guide rail 24 guide block 25 Telescopic mechanism 26 Guide cylinder 27 Rod 28 Gripper

Claims (3)

 A structure in which a male screw portion made of an insulator that can be screwed with a female screw to be inspected is provided on the tip end side of the probe barrel portion, and a flaw detection coil is embedded in one place in the circumferential direction at the tip portion of the male screw portion A screw part eddy current inspection probe characterized by comprising:  A slide bar extending in the axial direction is slidably provided on one side in the circumferential direction of the probe body corresponding to the installation position of the flaw detection coil, and the tip of the slide bar has a male screw portion as a female screw to be inspected. A coil position display device that is adapted to abut against the end face of the female screw when screwing, and to display the amount of the flaw detection coil entering the female screw according to the slide amount from the side position of the flaw detection coil at the tip of the slide bar The eddy current inspection probe for a screw part according to claim 1, comprising: A rotating mechanism comprising a base member for fixing at a required position, a shaft extending in the vertical direction, and a cylindrical portion rotatably attached to the outer periphery of the shaft; a guide rail extending in the vertical direction; elevating mechanism in the guide rail comprising a slidably mounted guide blocks, and the horizontal direction stretchable and the expansion mechanism is interposed in order to, an insulator made of that may screwed with the internal thread to be inspected externally threaded A gripper for gripping a screw portion eddy current inspection probe vertically downward having a configuration in which a probe is provided at a tip end side of a probe body portion and a flaw detection coil is embedded in one circumferential portion of the tip portion of the male screw portion A holding device for an eddy current inspection probe for a screw part, characterized by having a coupled configuration.

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