Method for inspecting bonded body, and apparatus for inspecting bonded body and bonded body

Abstract

An examination is performed on a joint body (17) in which a second pipe member (13) having a smaller outer diameter than a first pipe member (11) is inserted into a pipe of the first pipe member having a through hole (19), and the second pipe member is expanded to form a joint portion (15). An elastic wave vibration is imparted to the joint body of the first pipe member and the second pipe member, and in a field of view region (IA) including the joint portion which is optically measured in one, a vibration distribution of the first pipe member and a vibration distribution of the second pipe member measured through the through hole are acquired for a plurality of field of view regions different in position in the circumference of the joint body. Whether or not the joint of the joint portion as a whole is good is determined based on the vibration distributions.

Description

Technical Field

[0001] The present invention relates to a method for inspecting a joint, an apparatus for inspecting a joint, and a joint. Background Technology

[0002] In automotive components, joints are used to join metal tubular components with other components (joined components). Patent Document 1 describes a method where a tubular component is inserted through a hole in the joined component, the tubular component is expanded in diameter, and then pressed against the joined component, thereby joining the tubular component with the joined component. In this document, to expand the diameter of the tubular component, a coil is inserted into the tubular component, aligned with the hole in the joined component, and a pulsed high current flows instantaneously to the coil. This generates a magnetic field from the coil, which in turn generates eddy currents in the tubular component, causing the tubular component to expand in diameter due to the Lorentz force acting between the coil and the tubular component. This method is applicable to tubular components made of highly conductive materials such as aluminum. Furthermore, regarding productivity, although less efficient than the aforementioned techniques, mechanical methods similar to the joining state include methods such as inserting a telescopic mechanism inside the tubular component to expand the diameter, embedding an elastomer such as rubber inside the tubular component and expanding the diameter through its elastic deformation, and applying high pressure by introducing an incompressible fluid inside the tubular component. Furthermore, Patent Document 2 describes a technique for riveting tubular components together using electromagnetic forming.

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-131959

[0006] Patent Document 2: Japanese Patent Application Publication No. 2019-13955 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] As one method for checking whether the pipe component and the joined component are joined with sufficient strength after joining, as described above, is X-ray CT inspection. However, in X-ray CT inspection with a sufficiently wide field of view that can be applied to the inspection of such joints, it is difficult to detect gaps narrower than 1 μm. Furthermore, it is even impossible to evaluate the riveting condition, such as whether the riveted parts of the joint of the pipe component are reliably riveted. The presence or absence of such narrow gaps, or the riveting condition, can become a significant issue in terms of strength, for example, in automotive parts, thus requiring the establishment of inspection methods with high detection accuracy.

[0009] Therefore, the object of the present invention is to provide a method for inspecting a joint that can accurately detect minute gaps between the components of the joint or poor jointing caused by insufficient riveting, as well as an inspection device for the joint and a joint for the inspection.

[0010] Methods for solving problems

[0011] The present invention is composed of the following structure.

[0012] (1) A method for inspecting a joint, wherein a second pipe member having an outer diameter smaller than that of the first pipe member is inserted into a first pipe member having at least one through hole, and the second pipe member is expanded to form a joint.

[0013] Elastic wave vibration is imparted to the joint of the first and second pipe components.

[0014] In a field of view that includes the joint of the first and second tube components, measured optically together, the vibration distribution of the first tube component and the vibration distribution of the second tube component measured through the through hole are obtained in multiple field of view regions at different circumferential positions of the joint.

[0015] The quality of the overall joint is determined based on the obtained vibration distribution.

[0016] (2) An inspection device for a joint, wherein a second pipe member having a smaller outer diameter than the first pipe member is overlapped and joined inside the pipe of a first pipe member.

[0017] The inspection device for the assembly includes:

[0018] The excitation section imparts elastic wave vibration to the joint; and

[0019] The vibration detection unit, in a field of view that includes the joint of the first tube member and the second tube member, which is measured optically together, obtains the vibration distribution of the first tube member and the vibration distribution of the exposed portion of the second tube member, which is measured through a through hole formed in the first tube member, for multiple field of view areas with different circumferential positions of the joint.

[0020] (3) A joint in which at least a portion of a second pipe member having an outer diameter smaller than that of the first pipe member is inserted into the pipe of a first pipe member, and having a joint portion in which the inner circumferential surface of the first pipe member and the outer circumferential surface of the second pipe member are in close contact in an expanded state.

[0021] At least one through hole is formed at the joint of the first pipe member.

[0022] The joint of the second pipe member contacts the first pipe member without engaging with the inner edge of the through hole.

[0023] Invention Effects

[0024] According to the present invention, it is possible to reliably detect minor gaps between the pipe component and the joined component or poor joint caused by insufficient riveting. Attached Figure Description

[0025] Figure 1 This is a schematic structural diagram illustrating one embodiment of the inspection device for the joints involved in the present invention.

[0026] Figure 2 This is a schematic perspective view showing the appearance of an example of a joint.

[0027] Figure 3 It means to Figure 2 The diagram shown depicts the state of the assembly before electromagnetic forming. It is a schematic cross-sectional view illustrating an example of the arrangement of the forming fixture, the first tube component, the second tube component, and the coil for electromagnetic forming.

[0028] Figure 4 It is a schematic cross-sectional view illustrating the electromagnetic forming of the overlapping portion of the first and second tube components.

[0029] Figure 5 yes Figure 4 The enlarged cross-sectional view of the annular bulge and the joint shown is a diagram illustrating the high joint strength between the first tube member and the second tube member.

[0030] Figure 6 yes Figure 4 The enlarged cross-sectional view of the annular bulge and the joint shown is a diagram illustrating the weak joint strength between the first tube member and the second tube member.

[0031] Figure 7 This is a flowchart illustrating the steps of the inspection method for the joint.

[0032] Figure 8 The diagrams (A) to (C) illustrate the method for determining the vibration state of each point within the field of view.

[0033] Figure 9 This is a flowchart illustrating the steps of other inspection methods for the joint.

[0034] Figure 10 This is a schematic cross-sectional view of a joint in which a first tube member and a second tube member are electromagnetically formed using multiple segmented forming jigs.

[0035] Figure 11 It means to use Figure 10 The diagram shows a perspective view of the joint formed by electromagnetic forming using the forming fixture.

[0036] Figure 12 This is a schematic front view of the assembly.

[0037] Figure 13 These are explanatory diagrams showing examples of the configuration of through holes provided in the joint, as shown in (A) and (B). Detailed Implementation

[0038] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0039] <Structure of the inspection device>

[0040] Figure 1 This is a schematic structural diagram illustrating one embodiment of the inspection device for the joints involved in the present invention.

[0041] The inspection device 100 for the joint (hereinafter referred to as the "inspection device") uses elastic wave vibration to inspect the tightness of the joint 17, in which the first pipe member 11 and the second pipe member 13 are tightly joined at the joint 15. Based on the degree of tightness, the quality of the joint strength of the joint 17 can be determined. In the joint 17 of this structure, by forming a through hole 19 in the first pipe member 11 at the joint 15, allowing the second pipe member 13 to protrude from the through hole 19, the elastic wave vibration described later can be detected.

[0042] The inspection device 100 includes an excitation unit 21, a vibration detection unit 23, a relative movement mechanism 25, an evaluation unit 27, an input unit 29, an output unit 31, and a control unit 33 for controlling them.

[0043] The excitation unit 21 includes a signal generator 35 and an oscillator 37, which impart elastic wave vibration to the coupling body 17. The signal generator 35 is electrically connected to the oscillator 37 via a cable, and sends the generated alternating current signal to the oscillator 37. The oscillator 37 is used in contact with the coupling body 17, converting the alternating current signal received from the signal generator 35 into elastic wave vibration as a mechanical vibration, and imparting this elastic wave vibration to the coupling body 17.

[0044] The contact position between the oscillator 37 and the coupling body 17 can be either the first tube member 11 or the second tube member 13 constituting the coupling body 17, as long as it is a position that is axially away from the joint portion 15 of the second tube member 13 and does not include the viewing area IA described later. The shape of the oscillator 37 is not particularly limited, but a pointed front end is preferred in order to facilitate contact between the surface and the second tube member 13 (or the first tube member 11) formed by the curved surface, so as to reduce the contact area.

[0045] The vibration detection unit 23 includes a light irradiation unit 41, a light detection unit 43, and a vibration distribution determination unit 45, and together optically detects the distribution of the vibration state (amplitude and / or phase) of at least the exposed portion of the second tube member 13 exposed from the through hole 19 (hereinafter referred to as vibration distribution).

[0046] The light irradiation unit 41 includes a laser source 47 and a beam shaping lens 49. The laser source 47 emits pulsed laser light (pulsed laser LB) in a timing synchronized manner with the alternating current signal generated by the signal generator 35 of the excitation unit 21. The beam shaping lens 49 is a concave lens disposed between the laser source 47 and the conjugate 17.

[0047] In addition to being connected to the signal generator 35 of the excitation unit 21 via the control unit 33, the laser source 47 can also be directly connected to the signal generator 35 via cable. In this case, it can be synchronously controlled with high precision with the AC signal. The beam-shaping lens 49 has the function of expanding the irradiation area of ​​the pulsed laser LB, so that the pulsed laser LB from the laser source 47 irradiates the area of ​​the joint body 17 including at least the through hole 19 of the joint portion 15. Here, the entire range of the irradiated pulsed laser or the portion of the irradiation range including the through hole 19 of the joint portion 15 is defined as the field of view IA for detecting the vibration distribution.

[0048] The optical detection unit 43 detects the interference pattern formed by the interference of the reflected light from the pulsed laser LB in the field of view region IA with the reference light described in detail later.

[0049] The optical detection unit 43 is a so-called speckle misalignment interferometer 63, which includes a beam splitter 51, a first reflector 53, a second reflector 55, a phase shifter 57, a condenser lens 59, and an image sensor 61.

[0050] Beam splitter 51 is a semi-reflective mirror disposed at various points within the field of view IA at the incident position of reflected light reflected from the surface of the joint 17.

[0051] The first reflector 53 is disposed in the optical path of the first reflected light LR1, which is reflected by the beam splitter 51 from the surface of the joint body 17, and the second reflector 55 is disposed in the optical path of the second reflected light LR2, which is reflected by the beam splitter 51 from the surface of the joint body 17.

[0052] Phase shifter 57 is disposed between beam splitter 51 and first reflector 53 to change (shift) the phase of reflected light passing through phase shifter 57.

[0053] The image sensor 61 is positioned on the optical path of the first reflected light LR1, which is reflected by the beam splitter 51 and then by the first mirror 53 and passes through the beam splitter 51, and the second reflected light LR2, which is reflected by the second mirror 55 and then by the beam splitter 51, which is reflected by the beam splitter 51 and then by the beam splitter 51.

[0054] A condenser lens 59 is positioned between the beam splitter 51 and the image sensor 61.

[0055] The first reflector 53 is configured such that its reflecting surface is at a 45° angle relative to the reflecting surface of the beam splitter 51. In contrast, the second reflector 55 is configured such that its reflecting surface is at a slightly tilted angle relative to the reflecting surface of the beam splitter 51 from 45°.

[0056] Image sensor 61 has a large number of detection elements. Different detection elements detect reflected light from multiple points on the surface of the junction 17 within the field of view IA, which is incident on image sensor 61 through the first reflector 53 and the phase shifter 57, and reflected light that is incident on image sensor 61 through the second reflector 55. Each detection element outputs an electrical signal corresponding to the intensity of the detected light.

[0057] The vibration distribution determination unit 45 determines the vibration distribution in the field of view region IA through steps described in detail later, based on the electrical signal representing the interference pattern detected by the light detection unit 43.

[0058] The relative movement mechanism 25 is a device that rotates the first tube member 11 and the second tube member 13 of the coupling body 17 about their axis. It has a pair of gripping portions 39A and 39B that grip the ends of the coupling body 17, and a motor (not shown) that drives at least one of the gripping portions 39A to rotate. The relative movement mechanism 25 can change the rotational position of the coupling body 17 so that a portion of the through hole 19 of the coupling portion 15 of the coupling body 17 gripped by the gripping portions 39A and 39B is positioned within the field of view IA. Alternatively, the coupling body 17 can be manually moved by the operator without using the relative movement mechanism 25 to include the desired position within the field of view IA.

[0059] The evaluation unit 27 determines the quality of the joint state of the joint 15 based on the vibration distribution of the field of view IA determined by the vibration distribution determination unit 45, i.e., obtained by the vibration detection unit 23, as described later.

[0060] In addition, the inspection device 100 includes: an input unit 29 for the operator to input information into the inspection device 100; a display for displaying information such as the results determined by the evaluation unit 27; and an output unit 31, such as an output terminal, for outputting the signal of the determination result to the outside of the inspection device 100.

[0061] The control unit 33 causes each of the aforementioned units to operate according to instructions input from the input unit 29 or pre-prepared programs. In other words, the control unit 33, vibration distribution determination unit 45, evaluation unit 27, etc., are constituted by a computer device that includes hardware resources such as a CPU, memory, and storage units, and realize software-based driving and information processing of each unit.

[0062] <Joint>

[0063] Figure 2 This is a schematic perspective view showing the appearance of an example of a joint.

[0064] The joint 17 illustrated herein inserts and overlaps a second pipe member 13 having a smaller outer diameter than the first pipe member 11 inside the pipe of the first pipe member 11 having at least one through hole 19, and expands the overlapping portion of the second pipe member 13 by electromagnetic forming to form a joint 15.

[0065] The tube blank before electromagnetic forming of the first tube component 11 is not limited to a round tube, but can also be a square tube with a square or rectangular cross-section, a hexagonal tube with a hexagonal cross-section, or an octagonal tube with an octagonal cross-section, and can be manufactured by extrusion or welding of sheet metal. When the cross-sectional shape of the first tube component 11 is circular, it is preferable that the second tube component 13 also has a circular cross-section and is formed into a similar shape, but dissimilar irregular cross-sections can also be combined with each other.

[0066] The material of the first tube component 11 can be appropriately selected from steel (ordinary steel, high-tensile steel), aluminum alloy (e.g., JIS 6000 series, 7000 series, etc., as heat-treatable alloys), resin, etc.

[0067] The tube blank of the second tube component 13 before electromagnetic forming is the same as that of the first tube component 11, and is not limited to a round tube. It can also be a square tube with a square or rectangular cross-section, a hexagonal tube with a hexagonal cross-section, or an octagonal tube with an octagonal cross-section, and can be manufactured by extrusion or welding of sheet metal. The material of the second tube component 13 can preferably be an aluminum alloy capable of electromagnetic tube expansion (e.g., JIS 6000 series, 7000 series, etc., as heat-treatable alloys). The first tube component 11 and the second tube component 13 can be made of the same material or different materials.

[0068] Here, a joint is described using a first and second tube component with different diameters and circular cross-sections perpendicular to the axial direction, which are expanded by electromagnetic forming inside a forming fixture, and the components are riveted together. However, the object of inspection is not limited to this. In addition to electromagnetic forming, various methods such as hydraulic expansion or rubber expansion can be used as tube expansion methods.

[0069] To avoid reducing the joint strength of the riveted joint, it is preferable to set the diameter of the through hole 19 to be smaller than [a certain value]. When the wall thickness of the first pipe component 11 is set to 2mm, it is preferable to set it to... Hereinafter, it is preferred to set as The following. Furthermore, in any case, it is preferable to set the aperture to... above.

[0070] Electromagnetic forming

[0071] Figure 3 It means to Figure 2 The diagram showing the state of the assembly 17 before electromagnetic forming is a schematic cross-sectional view illustrating an example of the arrangement of the forming jig 71, the first tube member 11, the second tube member 13, and the coil 73 for electromagnetic forming.

[0072] The forming fixture 71 has a push-pressing part 71a that withstands the force of expansion of the first tube member 11 and the second tube member 13 when a Lorentz force is generated on the second tube member 13 due to the excitation magnetic field from the coil 73 during electromagnetic forming. Preferred materials for the forming fixture 71 include steel (e.g., SUS304, SS400), extruded aluminum, aluminum castings, and resin injection molding materials. In this structure, the forming fixture 71 is divided into multiple blocks in the circumferential direction of the first tube member 11. These blocks are interconnected by suitable fastening mechanisms such as bolts to form an annular push-pressing part 71a.

[0073] As preparation for electromagnetic forming, firstly, one end 11a of the first tube member 11 is inserted into one end 13a of the second tube member 13, forming an overlap 75 where the first tube member 11 and the second tube member 13 radially coincide. A forming jig 71 is arranged circumferentially outside this overlap 75. Furthermore, a coil 73 for electromagnetic forming is arranged inside the second tube member 13. The above arrangement sequence is an example and is not limited to it; any order can be followed.

[0074] Although not shown in the diagram, coil 73 is connected to an external power source via a conductor and is inserted into the tube of the second tube member 13 by a sliding action performed manually or using a known moving mechanism. Furthermore, coil 73 is positioned at the desired location and fixed in the axial direction by a suitable fixing mechanism. The first tube member 11, the second tube member 13, and coil 73 are arranged concentrically with each other. Additionally, the distance between the push-press portion 71a on the inner side of the forming jig 71 and the outer peripheral surface of the first tube member 11 is fixed.

[0075] At least one through hole 19 is formed in the first tube member 11. Only one through hole 19 may be provided, but it is preferable to provide multiple through holes at different locations. The pressing portion 71a of the forming jig 71 is positioned radially outward of the through hole 19. In other words, the pressing portion 71a of the forming jig 71 is configured to overlap radially, covering the through hole 19, on the radially outward side of the first tube member 11.

[0076] The through hole 19 is circular (perfect circle) when viewed from above, but it is not limited to this. It can also be a polygon such as a triangle or quadrilateral, or other shapes such as an ellipse or an L-shape.

[0077] Through Figure 3 When coil 73 is energized in the state shown, the second tube member 13 electromagnetically expands. At this time, an energy of approximately 16 kJ is instantaneously injected into coil 73 from a power source not shown, inducing eddy currents in the second tube member 13 opposite to coil 73. These eddy currents generate a Lorentz force in the second tube member 13 toward the radially outward direction, and the generated Lorentz force expands the second tube member 13.

[0078] Figure 4 This is a schematic cross-sectional view showing the electromagnetic forming of the overlap 75 between the first tube member 11 and the second tube member 13.

[0079] When the second tube member 13 expands, the first tube member 11 expands in accordance with the expansion deformation of the second tube member 13. The outer peripheral surface of the first tube member 11 is pressed tightly against the push portion 71a of the forming jig 71, thereby limiting the expansion diameter. Furthermore, the expansion of the second tube member 13 and the first tube member 11 is further advanced on both sides of the push portion 71a in the tube axis direction. As a result, on both sides of the forming jig 71 in the tube axis direction, annular bulges 77A and 77B that bulge outward radially are formed at the locations overlapping the areas where the coils 73 are arranged.

[0080] In this configuration, the annular bulge 77A is mainly formed on the second tube member 13, and the annular bulge 77B is mainly formed on the first tube member 11. Furthermore, on the side of the forming jig 71 relative to the maximum diameter 79A of the annular bulge 77A, the tube end 11a of the first tube member 11 is expanded along the inclined surface 81A of the second tube member 13. In the annular bulge 77B, on the side of the forming jig 71 relative to the maximum diameter 79B of the first tube member 11, the tube end 13a of the second tube member 13 is expanded radially outward, forming the inclined surface 81B on the first tube member 11.

[0081] The second tube member 13, which is opposite to the through hole 19 of the first tube member 11, hardly bulges out radially outward within the through hole 19. Therefore, the second tube member 13 is maintained in a state where it does not engage (rivet) with the inner edge of the through hole 19.

[0082] <Jointing State and Propagation Characteristics of Elastic Wave Vibration>

[0083] Here, the joining state of the joint 15 formed by electromagnetic forming as described above will be explained in more detail.

[0084] Figure 5 , Figure 6 yes Figure 4 An enlarged cross-sectional view of the annular bulge 77A and the joint 15 shown. Figure 5 This diagram shows a state where the joint strength between the first pipe member 11 and the second pipe member 13 is high. Figure 6 This diagram shows the state where the joint strength between the first pipe member 11 and the second pipe member 13 is weak.

[0085] like Figure 5 As shown, through the electromagnetic expansion of the second tube member 13, the first tube member 11 is pressed against the push-press portion 71a of the forming jig 71, and the portion of the tube end 11a that is close to and deviates from the push-press portion 71a expands in diameter along the inclined surface 81A of the second tube member 13. The expansion force of the second tube member 13 is locally concentrated at the edge 71b of the push-press portion 71a, and a bend 85 caused by stress concentration is formed in the first tube member 11 and the second tube member 13 corresponding to the edge 71b, and a riveting portion of the first tube member 11 and the second tube member 13 is formed at the bend 85. When the riveting portion is formed, the tightness of the joint 15 is also high.

[0086] On the other hand, such as Figure 6 As shown, according to the conditions of electromagnetic expansion tubes, the bending portions 87 of the first tube member 11 and the second tube member 13 corresponding to the edge portion 71b of the push-press portion 71a will not generate large stress concentrations. As a result, sometimes no riveting portion is formed, resulting in a relatively loose joint state. In this case, the tightness of the joint portion 15 becomes low.

[0087] like Figure 5 As shown, a riveting portion is formed at the bend 85 of the first tube member 11 and the second tube member 13 by electromagnetic forming, so that the first tube member 11 and the second tube member 13 are in a firmly joined state and as shown in the figure. Figure 6 As shown, the vibration propagation characteristics of the pipe component differ under relaxed engagement conditions.

[0088] In other words, when the first pipe member 11 and the second pipe member 13 are firmly joined, such as Figure 5As indicated by the middle arrow EV, if an elastic wave vibration is applied from a location away from the joint 15 to avoid the through hole 19 of the second tube member 13, the elastic wave vibration propagates towards the joint 15. The elastic wave vibration also propagates from the second tube member 13 to the first tube member 11 at the tube end 11a, and is divided into vibrations shown by arrow EV1 along the second tube member 13 and vibrations shown by arrow EV2 along the first tube member 11. These vibrations propagate along the second tube member 13 and the first tube member 11. Similarly, in Figure 6 In the relaxed engagement state shown, the propagating elastic wave vibration is also divided from the tube end 11a of the first tube member 11 into vibration represented by arrow EV1 and vibration represented by arrow EV2.

[0089] The vibrations represented by arrow EV1 and arrow EV2, respectively, propagate from the second tube member 13 to the first tube member 11 in different states depending on the engagement. When the engagement is firm and the fit is tight, EV1 and EV2 vibrate as a single unit. Conversely, when the engagement is loose and the fit is weak, EV1 and EV2 vibrate independently, resulting in different intensity ratios of their vibrations at the joint 15.

[0090] Therefore, a through hole 19 is formed in the region of the joint 15, and the vibration distribution caused by the elastic wave vibration of the second pipe member 13 is obtained from LR1 through the through hole 19. Furthermore, the vibration distribution caused by the elastic wave vibration of the first pipe member 11 near the through hole 19 is obtained from LR2. Then, the tightness of the fit at the location of the through hole 19 is evaluated based on the difference in vibration distribution between the two. In other words, by detecting the vibration distribution of the second pipe member 13 exposed through the through hole 19 formed at any position in the joint 15 and the vibration distribution of the first pipe member 11 near the through hole 19 using the inspection device 100 described above, the tightness of the fit at any position in the joint 15 can be accurately evaluated based on the differences in the detected vibration distributions. In this way, the tightness of the joint 15, which is difficult to measure, becomes clear, and therefore, the mechanical strength of the joint 17 can be accurately determined, and its suitability can be judged with high precision.

[0091] <Inspection Methods for Joints>

[0092] Next, the steps of the inspection method for evaluating the tightness of the joint 17 formed by joining the first pipe member 11 and the second pipe member 13 using the inspection device 100 will be described in detail.

[0093] Figure 7 This is a flowchart illustrating the steps of the inspection method for the joint. The following explanation follows based on this flowchart. Furthermore, the steps described below are performed using… Figure 1The control unit 33 shown executes automatically according to a predetermined program or based on operator input information, or through manual operation by the operator.

[0094] First, the operator uses the gripping portions 39A and 39B of the relative movement mechanism 25 to grip the end of the coupling body 17. Then, the relative movement mechanism 25 is driven, or operated by the operator, to position the coupling portion 15 of the coupling body 17 within the field of view IA of the inspection device 100. Figure 1 Inside the inspection device 100, the assembly 17 is placed (step 101, hereinafter referred to as S101).

[0095] The field of view IA is a planar region viewed from the speckle misalignment interferometer 63 side. In contrast, the joint 15 is curved on the circumferential surface of the tubular joint 17, so only a portion of the outer circumferential surface of the joint 15 is included in one field of view IA. Therefore, after measuring vibration using one field of view IA, the entire circumferential measurement of the joint 15 is performed by repeatedly rotating the joint 17 by (360 / n)° using the relative movement mechanism 25 and measuring in other circumferential positions within the field of view IA. When a through-hole 19 exists in the field of view IA, the second tubular member 13 exposed through the through-hole 19 is measured. Here, the number of times the joint 17 is rotated to change the field of view IA is n (n is an integer greater than or equal to 2). The n field of view IAs for which vibration measurements are performed are denoted as IA1, IA2, ..., IA... n Here, let n = 4, so that the angle of rotation of the joint 17 is 90° each time.

[0096] First, measurements were taken in the IA1 visual field.

[0097] Within a field of view, m measurements (m being an integer greater than or equal to 3) are performed to make the phase of the vibration of the oscillator 37 different. The phase of the vibration of the oscillator 37 is the phase of the alternating current signal sent from the signal generator 35 to the oscillator 37, which corresponds to the phase at the contact point between the excited vibration of the coupling body 17 and the oscillator 37. Here, let m = 3, and use the phase index k (an integer from 1 to m) to represent each measurement as "the k-th measurement".

[0098] First, as the first measurement, k is set to 1 (S102). Then, by sending an alternating current signal from the signal generator 35 to the oscillator 37, vibration is introduced from the oscillator 37 to the coupling body 17 (S103).

[0099] Next, the phase of the oscillation of oscillator 37 is set using a given initial value (e.g., And by At each specified timing, signal generator 35 sends a pulse signal to laser source 47. During this phase, k = 1, therefore the phase of the oscillator 37's vibration when the pulse signal is sent is... The laser source 47 repeatedly emits pulsed laser LB each time a pulse signal is received. The beam spot of the pulsed laser LB is expanded by the beam shaping lens 49 and illuminates the surface of the conjugate 17, which includes the field of view region IA (S104).

[0100] The pulsed laser LB is reflected at the surface of the joint 17 and incident on the beam splitter 51 of the speckle misalignment interferometer 63. A portion of this reflected light (the first reflected light LR1) is reflected by the beam splitter 51, then reflected by the first mirror 53 after passing through the phase shifter 57, and after passing through the phase shifter 57 again, a portion passes through the beam splitter 51, passes through the condenser lens 59, and is incident on the image sensor 61. Furthermore, the remaining portion of the reflected light incident on the beam splitter 51 (the second reflected light LR2) passes through the beam splitter 51 and is reflected by the second mirror 55. A portion of this reflected light, after being reflected by the beam splitter 51, passes through the condenser lens 59 and is incident on the image sensor 61. The image sensor 61 uses different detection elements to detect the reflected light reflected from multiple points on the surface of the joint 17. Among the detection elements, in addition to the reflected light reflected from a specific point on the surface of the joint 17, reflected light reflected from points slightly offset from that specific point is also incident.

[0101] During the repeated output of the reflected light (first reflected light LR1) of the pulsed laser LB, the phase shifter 57 causes a phase change (shift) in the illumination light passing through the phase shifter 57. As a result, the phase difference between the reflected light reflected from a specific point on the surface of the junction 17 and incident on a specific detection element of the image sensor 61, and the reflected light reflected from a point slightly offset from that specific point and incident on the same detection element, changes. During this phase difference change, each detection element of the image sensor 61 detects the intensity of the interference light resulting from the interference of these two reflected lights (S105).

[0102] Figure 8 This is an explanatory diagram showing the vibration state of each point within the field of view IA in (A) to (C).

[0103] exist Figure 8 In (A), the phase of the oscillation of oscillator 37 is represented by a curve as follows: An example of the phase shift of phase shifter 57 and the intensity of interference light detected by the detection element of image sensor 61. Additionally, in Figure 8In (A), a continuous curve represents the sinusoidal relationship between the detected intensity and the phase shift, but in reality, discrete data is measured. Therefore, in order to reproduce the aforementioned continuous sinusoidal waveform from the measured discrete data using methods such as least squares, it is necessary to detect the intensity at at least three different phase shifts.

[0104] Next, it is confirmed whether all measurements of the phase differences of the m (m=3) vibrations have been completed (S106). At this stage, the phase index k=1, and the phase index k has not reached m (m=3), so the phase index k is increased by only 1 to become "2" (S107).

[0105] Next, returning to S104, the phase of the oscillation of oscillator 37 is... k = 2, that is At each timing interval, the signal generator 35 sends a pulse signal to the laser source 47. The laser source 47, upon receiving the pulse signal, repeatedly irradiates the surface of the assembly 17 with pulsed laser LB.

[0106] Then, the phase shifter 57 causes the phase change (shift) of the reflected light reflected from each point in the field of view IA1 to be at least three values, and each detection element of the image sensor 61 detects the intensity of the interference light (S105).

[0107] exist Figure 8 In (B), the phase of the vibration of oscillator 37 under the second measurement (k=2) is represented by a curve. The phase shift of phase shifter 57 and the intensity of interference light detected by the detection element of image sensor 61 are obtained at that time. Figure 8 Comparing graph (B) with graph (A), the peak positions P0 and P1 of the interference light intensity shift. This offset indicates that the phase difference between the reflected light from a specific point on the surface of the joint 17 and the reflected light from a point slightly offset from that specific point changes according to the phase of the vibration of the oscillator 37 during detection. This change in the phase difference of the optical path indicates that the relative positions of the out-of-plane vibration directions of these two points are changing.

[0108] Thus, after performing operation S105 in the second measurement (k=2), the phase index k has not yet reached m (m=3) in S106, so the phase index k is increased by only 1 to become "3" (S107). Then, returning to S104, the phase of the alternating current signal is... k=3, that is At each timing interval, the laser source 47 repeatedly irradiates the surface of the bonding body 17 with pulsed laser LB, and the detection elements of the image sensor 61 detect the intensity of the interference light (S105).

[0109] Thus, as Figure 8 As shown in (C), the phase of the alternating current signal is obtained as The relationship between the phase shift of phase shifter 57 and the intensity of interference light.

[0110] Then, in S106, the phase index k is 3 and reaches m (m=3), so the transmission of AC signal from signal generator 35 to oscillator 37 stops, thereby oscillator 37 stops vibrating (S108).

[0111] With the operations up to this point, the acquisition of data in the field of view IA1 is complete.

[0112] In S109, it is determined whether the acquisition of data in all fields of view has been completed. Here, since it is the stage where the vibration measurement of field of view IA1 has ended, the coupling body 17 is rotated (360 / n)° around its axis by the relative movement mechanism 25, changing the orientation of the coupling body 17. As a result, the field of view IA1 is changed to the field of view IA2 (S110).

[0113] Then, returning to S103, by performing the operations of S103 to S108 on the new field of view IA2, the relationship between the phase shift of each point in the field of view IA2 and the intensity of the interference light is obtained.

[0114] Next, in S109, it is determined whether the acquisition of data in all field-of-view areas has been completed. Here, since the vibration measurement stage of field-of-view area IA2 has ended, in S110, the field-of-view area is changed from IA2 to IA3 again. Then, by performing the above-described operations S103 to S108 on the new field-of-view area IA3, the relationship between the phase shift of each point in field-of-view area IA3 and the intensity of the interference light is obtained.

[0115] If the above operations are completed, the vibration measurement is finished. Then, the obtained data is analyzed. One data point is analyzed for each of the n (n=3) field-of-view regions (IA1, IA2, IA3). First, the vibration distribution at each point in field-of-view region IA1 is determined.

[0116] First, for each detection element of the image sensor 61, in each vibration phase as well as In the process, during the period when the phase shift based on phase shifter 57 changes, the maximum output phase shift at the position (P0, P1, P2) where the output of the detection element reaches its maximum peak value is determined. (Refer to Figure 8 (Charts (A) to (C)).

[0117] Then, calculate the difference in maximum output when the phases of the vibrations are different. as well as The difference between these three maximum output phase shifts represents the relative displacement of the out-of-plane vibration direction of a specific point in the field of view and a point slightly offset from that specific point, as two sets of data with different phases (i.e., different times) of the vibration of oscillator 37, totaling three sets (S111). Based on these three sets of relative displacements, the values ​​of three parameters are obtained for each point in the field of view: the amplitude of the vibration, the phase of the vibration, and the center value of the vibration (DC component) (S112).

[0118] The amplitude and phase values ​​of the vibrations at each point obtained in this way provide information indicating whether the connection at the joint 15 is good or bad, as follows. As described above, when the first tube member 11 and the second tube member 13 are well connected, they are mutually constrained, and therefore vibration is attenuated near the joint 15. Conversely, when there is a small gap between the first tube member 11 and the second tube member 13, and they are not well connected, the first tube member 11 and the second tube member 13 are not constrained to each other at and around the joint 15, and vibration is not attenuated. Therefore, based on the vibration distribution in the joint 15, the quality of the connection can be determined (S113).

[0119] In the case of the aforementioned joint 15, a large portion of the viewing area IA becomes the outer peripheral surface of the first pipe member 11, which is located radially outward of the second pipe member 13. Here, the joint between the first pipe member 11 and the second pipe member 13 is as described above. Figure 5 In the case of a small area being riveted together as shown in the bend 85, depending on the riveting condition, even if the vibration of the outer first tube member 11 is sufficiently attenuated, the vibration of the inner second tube member 13 may not be attenuated. Such a situation may occur, for example, when the other circumferential portions of the first tube member 11 are firmly joined to the second tube member 13 with a high degree of fit, but only a portion of the circumferential direction (the portion of the field of view IA) is in a state of low fit between the first tube member 11 and the second tube member 13 due to insufficient riveting.

[0120] Therefore, in this method for inspecting the joint, by forming a through hole 19 in the first tube member 11 of the joint 15, the second tube member 13, whose outer peripheral surface is hidden by the first tube member 11, is exposed through the through hole 19. The vibration distribution of the exposed outer peripheral surface of the second tube member 13 is measured together with the vibration distribution of the first tube member. As a result, the vibration distribution of the second tube member 13 in the joint 15 can be measured, and a more accurate evaluation of the fit can be performed.

[0121] Therefore, the through hole 19 is preferably located at a position in the joint 15 that particularly affects the joint strength. For example, examples can be cited. Figure 5 Near the bend 85 shown, or at the center of the joint 15 in the tube axis direction, etc. Furthermore, it is preferable to arrange the through hole 19 at any position as needed, and measure the vibration distribution of the second tube member 13 at the location of the through hole 19.

[0122] Thus, after determining whether the joint (tight fit) of the joint 15 in the field of view IA1 is good or bad, the same determination of whether the joint is good or bad is made for the other field of view IA2, IA3, and IA4 in turn (S114).

[0123] Furthermore, in the example above, the number of measurements was m (m=3) by making the phases of the vibrations different. However, by making the number of measurements m larger than the number represented by [2N+1] (N is a natural number greater than 2), the Nth harmonic component (Nth harmonic component) of the vibration excited by the joint 17 can be detected. In this way, the quality of the joint (tight fit) in the joint 15 can also be determined based on the vibration distribution of these harmonic components, along with the fundamental wave.

[0124] <Inspection Methods for Joints Subjected to Vibrations Under Multiple Different Conditions>

[0125] Next, a second inspection method for a joint, which further improves the inspection accuracy compared to the first inspection method by subjecting the above-described inspection method for the joint to vibrations under multiple different conditions, will be described.

[0126] Figure 9 This is a flowchart illustrating the steps of the second inspection method. In the following description, for... Figure 7 The flowcharts shown use the same symbols (step numbers) for the same steps, thus simplifying or omitting their descriptions.

[0127] The second inspection method has the same steps as the first inspection method, except that it adds steps S201 and S202 to the steps of the first inspection method described above, and changes step S113 to step S203.

[0128] In the inspection method for the second joint, within a field of view, various vibration states are measured by differentiating either the position where the oscillator 37 contacts the joint 17 (i.e., the position where vibration is imparted) or the vibration frequency of the oscillator 37. Here, the number of vibration states is set to M (M is an integer greater than or equal to 2). The more types of vibration states there are, the more reliably the goodness or badness of the joint can be determined, but correspondingly, the measurement time increases. Therefore, it is usually preferable to set about 3 to 5 types.

[0129] In the following description, the position and frequency of the vibration will be referred to as the "vibration-assigning conditions".

[0130] First, similar to the first inspection method described above, the joint 17 is placed on the inspection device 100 (S101), and steps S102 to S108 are performed on the field of view area IA1 with the first vibration condition.

[0131] Then, steps S103 to S108 are repeated until the measurement of all types (M kinds) of vibration-imposed conditions is completed (S201). In other words, steps S103 to S108 are performed when changing from the first vibration-imposed condition to the second vibration-imposed condition (S202), that is, changing the position of the oscillator 37 and / or the vibration frequency of the oscillator 37. Furthermore, the above steps are repeated when changing from the second vibration-imposed condition to the third vibration-imposed condition. In this way, the measurement of all vibration-imposed conditions (M kinds) is completed.

[0132] After performing steps S103 to S201 for the field of view IA1, steps S103 to S201 (S109, S110) are also performed sequentially for the field of view IA2, IA3, and IA4. If the above steps have been performed for all field of view areas, the vibration distribution in the field of view IA1 is calculated (S111, S112), and the quality of the connection is determined as follows.

[0133] In the case of a well-fitted joint where the joint 15 is firmly engaged, and in the case of a loose joint, the vibration distribution varies depending on the vibration generation conditions in the joint 15. Therefore, it is possible to determine the quality of the engagement near the joint 15 based on the detected vibration distribution.

[0134] However, when a standing wave is generated in the joint 17, the vibration amplitude also decreases. Therefore, if the quality of the joint is judged only under one vibration condition, it is possible to make an erroneous judgment that the joint is good even if a node of a standing wave is accidentally formed at the joint 15 despite poor jointing. Therefore, the vibration state is measured only for a field of view under multiple vibration conditions, and if it is confirmed under all vibration conditions that the vibration amplitude of the joint 15 decreases, the joint is judged to be good (S203).

[0135] After the determination of a visual field region IA1 in S203 is completed, the next visual field region is changed (S115). The above steps S111 to S203 are repeated for visual field regions IA2, IA3, and IA4 (S114) until the determination of all visual field regions is completed (S114).

[0136] That concludes the series of actions.

[0137] According to this inspection method, it is possible to prevent the misjudgment of the quality of the joint due to the nodes of the standing wave of vibration, and to evaluate the tightness of the joint 15 more accurately.

[0138] <Other examples of electromagnetic forming and inspection methods for the joints in this case>

[0139] Next, other examples of electromagnetic forming of the joint 15 will be described.

[0140] The aforementioned joint 15 as Figure 3 As shown, a second tube member 13 is inserted into the first tube member 11, forming an overlap portion 75 that overlaps the two tubes radially. This overlap portion 75 is formed by electromagnetic expansion. Here, the forming jigs arranged radially outside the first tube member 11 are changed from a ring-shaped structure to a structure arranged in a circumferentially segmented configuration. As a result, the first tube member 11 and the second tube member 13, especially the portions pressed by the multiple forming jigs, engage with each other with a greater degree of tightness.

[0141] Figure 10 This is a schematic cross-sectional view of the joint 17A, which shows the electromagnetic forming of the first tube member 11 and the second tube member 13 using multiple divided forming jigs 71A, 71B, 71C, and 71D.

[0142] The first tube member 11, which is expanded by the electromagnetic expansion of the second tube member 13, is pressed against the push-press portions 71a of a plurality of (four in this example) forming jigs 71A, 71B, 71C, and 71D. Joint portions 15A, 15B, 15C, and 15D are formed at these pressed positions. Through holes 19 formed in the first tube member 11 are located at the positions of each joint portion 15A, 15B, 15C, and 15D of the first tube member 11, but are not limited thereto; they can be located at any position.

[0143] Figure 11 It means to use Figure 10 A perspective view of the appearance of the electroforming assembly 17A shown in the forming fixture.

[0144] Four quadrilateral indentations 91 are formed on the outer peripheral surface of the first tube member 11 at a total of four locations, which are pressed against the forming jig. The inner area of ​​each indentation 91 becomes Figure 10 The joints 15A, 15B, 15C, and 15D are shown. A through hole 19 is formed inside the indentation 91, and the outer peripheral surface of the second pipe member 13 is exposed through the through hole 19.

[0145] A pair of annular bulges 77A and 77B are formed on both sides of the indentation 91, i.e., the joint 15 (15A, 15B, 15C, 15D), in the tube axis direction. Radial outward bulges 93 are formed between each other in the joint 15 along the circumferential direction. The bulges 93 are formed on both the first tube member 11 and the second tube member 13. Furthermore, the inner side of the indentation 91 is a flat portion.

[0146] Figure 12 This is a schematic front view of the assembly 17A.

[0147] In this case, when the elastic vibration wave indicated by arrow EV of the second pipe member 13 propagates towards the pipe end 13a, the elastic vibration wave attenuates in the joint 15 if a good joint strength is achieved. Therefore, by inspecting the vibration distribution of the second pipe member 13 exposed from the through hole 19 using the aforementioned joint inspection method, the joint condition of the first pipe member 11 and the second pipe member 13 in the joint 15 can be evaluated. Furthermore, since the area of ​​the joint 15 is a flat portion, vibration observation becomes easier compared to the cylindrical case.

[0148] The entire area of ​​the joint 15 is the area where the first tube member 11 and the second tube member 13 are in close contact, but the tightness decreases depending on the riveting state of the first tube member 11 and the second tube member 13 at the edge of the joint 15. This decrease in tightness can be detected by the vibration distribution of the first tube member 11 and the second tube member 13 observed through the through hole 19.

[0149] Figure 13 These are explanatory diagrams showing an example of the configuration of the through hole 19 provided in the area of ​​the joint 15, as shown in (A) and (B).

[0150] The through hole 19 can be positioned anywhere, but it can also be positioned near areas prone to riveting defects, for example. In this case, by detecting vibration distribution through the through hole 19, the location of the riveting defect can be easily determined. Specifically, as... Figure 13 As shown in (A), a through hole 19 can also be provided at the corner of the joint 15, such as... Figure 13 As shown in (B), through holes 19 may also be provided at the center of each side of the joint 15.

[0151] Thus, the through hole 19 is preferably positioned near the part where the engagement state of the joint 15 is to be evaluated in particular detail, and can be appropriately selected according to the evaluation purpose or the shape and size of the joint 15.

[0152] Thus, the present invention is not limited to the above-described embodiments. Combining the various structures of the embodiments with each other, making changes and applications based on the description in the specification and known technologies, and being made by those skilled in the art are also intended solutions of the present invention, and are included within the scope of protection.

[0153] In methods for measuring the vibration distribution within a field of view, besides the speckle misalignment method described above, other methods include the speckle method, grid projection method, sampled moiré fringe method, digital image correlation method, and laser Doppler method. The speckle misalignment method, as described above, involves interfering the reflected light from a light source illuminating points within the field of view with reference light reflecting the illuminating light from points near those points, and then determining the vibration distribution within the field of view based on the interference pattern. The speckle method involves interfering the reflected light from a light source illuminating points within the field of view with reference light branching from the illuminating light between the light source and the field of view, and then determining the vibration distribution within the field of view based on the interference pattern. Furthermore, as a variation of the speckle misalignment method, the reflected light from a light source illuminating points within the field of view can also be interfered with reference light reflecting the illuminating light from multiple points in their vicinity, and then the vibration distribution within the field of view can be determined based on the interference pattern.

[0154] Furthermore, the vibration distribution can also be measured by illuminating the field of view with a flash lamp other than the aforementioned pulsed laser. Even in this case, by controlling the timing of the elastic wave vibration and the flash lamp illumination, the out-of-plane displacement of each point within the field of view can be measured in at least three distinct phases of the vibration. This method allows for the easy acquisition of the vibration distribution within the field of view.

[0155] As stated above, the following matters are disclosed in this specification.

[0156] (1) A method for inspecting a joint, wherein a second pipe member having an outer diameter smaller than that of the first pipe member is inserted into the pipe of a first pipe member having at least one through hole, and the second pipe member is expanded to form a joint.

[0157] Elastic wave vibration is imparted to the joint of the first and second pipe components.

[0158] In a field of view that includes the joint of the first and second tube components, measured optically together, the vibration distribution of the first tube component and the vibration distribution of the second tube component measured through the through hole are obtained in multiple field of view regions at different circumferential positions of the joint.

[0159] The quality of the overall joint is determined based on the obtained vibration distribution.

[0160] According to the inspection method of this joint, even in a joint formed by joining overlapping first and second pipe components, the second pipe component overlapping the first pipe component can be exposed by forming a through hole in the first pipe component, and the vibration distribution of the second pipe component can be detected through the through hole. Moreover, the tightness between the first and second pipe components at the joint can be evaluated with high precision based on the detected vibration distribution of the first and second pipe components.

[0161] (2) The inspection method for the joint as described in (1), wherein,

[0162] In each of the plurality of said field-of-view regions,

[0163] The vibration distribution is measured by applying multiple elastic wave vibrations of different positions and frequencies to the joint body. If all the measured vibration distributions have nodes of standing waves at the joint, the joint body is determined to be well-joined within the field of view.

[0164] According to the inspection method for this joint, when the joint is well-joined, the nodes of a standing wave typically vibrate at the joint location regardless of the position or frequency of the vibration applied to the joint. However, if multiple types of vibration distributions all exhibit nodes of vibration at the joint, the joint can be deemed well-joined. The presence or absence of vibration nodes is easier to identify than the presence or absence of vibration continuity, thus making it easier to determine the quality of the joint. However, in vibration distributions based on a single type of vibration, nodes of a standing wave may occasionally exist at the joint regardless of the quality of the joint; therefore, vibration distributions are obtained separately from multiple vibrations.

[0165] Furthermore, when multiple vibrations of different frequencies are applied to the joint, the joint can be vibrated at different times for each of these frequencies, and then the vibration distribution can be measured. Alternatively, the vibration distribution at each frequency can be determined by frequency analysis based on the application of multiple overlapping vibrations at once. The former is preferred because it is easier to analyze the data than the latter, while the latter is preferred because it reduces the measurement time required compared to the former.

[0166] (3) The inspection method for the joint according to (1) or (2), wherein,

[0167] The field of view area is illuminated by a flash.

[0168] The vibration distribution is determined by controlling the timing of the elastic wave vibration and the flash illumination, and measuring the out-of-plane displacement of each point in the field of view during at least three distinct phases of the elastic wave vibration.

[0169] According to the inspection method of this assembly, the vibration distribution within the field of view can be easily obtained by measuring the out-of-plane displacement of each point within the field of view during at least three distinct phases of vibration.

[0170] (4) The method for inspecting the joint according to any one of (1) to (3), wherein the periphery of at least the through hole of the first pipe member is formed as a flat surface.

[0171] According to the inspection method of this joint, vibration distribution can be easily detected compared to the case of a curved surface.

[0172] (5) An inspection device for a joint, wherein a second pipe member having a smaller outer diameter than the first pipe member is overlapped and joined inside the pipe of a first pipe member.

[0173] The inspection device includes:

[0174] The excitation section imparts elastic wave vibration to the joint; and

[0175] The vibration detection unit, in a field of view that includes the joint of the first tube member and the second tube member, which is measured optically together, obtains the vibration distribution of the first tube member and the vibration distribution of the exposed portion of the second tube member, which is measured through a through hole formed in the first tube member, for multiple field of view areas with different circumferential positions of the joint.

[0176] According to the inspection device of the joint, for the elastic wave vibration imparted from the excitation unit to the second pipe member and propagating to the second pipe member and the first pipe member, the vibration detection unit detects both the vibration of the first pipe member and the vibration of the second pipe member observed through the through hole of the first pipe member, and can obtain information on the vibration distribution obtained only from the surface of the first pipe member.

[0177] (6) The inspection device for the joint according to (5) further includes an evaluation unit that determines the tightness of the first tube member and the second tube member in the joint based on the vibration distribution of the exposed portion detected.

[0178] The inspection device for this joint allows for the evaluation of the joint status by determining the tightness based on the vibration distribution.

[0179] (7) An inspection device for the joint according to (5) or (6), wherein,

[0180] The vibration detection unit includes:

[0181] The light irradiation section irradiates a field of view of the first tube component, including at least the through hole, with a laser.

[0182] The optical detection unit detects the interference pattern formed by the interference of the reflected light from the laser beam in the field of view with a reference light; and

[0183] The vibration distribution determination unit determines the vibration distribution based on the interference pattern.

[0184] According to the inspection device of the assembly, the vibration distribution can be detected with high precision from the interference pattern of the reflected light obtained by irradiating the laser and the reference light.

[0185] (8) The inspection device for the joint according to (7), wherein,

[0186] By changing the timing of the elastic wave vibration output by the excitation unit and the timing of the laser irradiation unit irradiating the field of view area,

[0187] The vibration detection unit measures the displacement of each point in the out-of-plane vibration direction within the field of view at least three different phases of the elastic wave vibration, and calculates the vibration distribution.

[0188] According to the inspection device of the joint, the elastic wave vibration is synchronized with the laser irradiation, and the joint is given elastic wave vibrations with different phases. Thus, the vibration distribution of the field of view can be determined by the relative displacement of the joint.

[0189] (9) The inspection device for the joint according to (7) or (8) further comprises a relative movement mechanism that moves the joint and the light irradiation part relative to each other to change the irradiation position of the laser from the light irradiation part.

[0190] The inspection device for this joint can change the laser irradiation position and detect the vibration distribution at any position of the joint.

[0191] (10) A joint in which at least a portion of a second pipe member having an outer diameter smaller than that of the first pipe member is inserted into the pipe of a first pipe member, and having a joint in which the inner circumferential surface of the first pipe member and the outer circumferential surface of the second pipe member are in close contact in an expanded state.

[0192] At least one through hole is formed at the joint of the first pipe member.

[0193] The joint of the second pipe member does not engage with the inner edge of the through hole but contacts the first pipe member.

[0194] According to this joint, since the second tube member is exposed through the hole of the first tube member, the vibration distribution of the first tube member and the vibration distribution of the exposed portion of the second tube member can be directly detected. Therefore, the tightness of the joint can be easily evaluated.

[0195] (11) The joint according to (10), wherein,

[0196] The joint of the first pipe member has a flat portion at least at a location in the circumferential direction.

[0197] According to this joint, vibration distribution can be easily detected compared to the case of a curved surface.

[0198] (12) The joint according to (10) or (11), wherein the joint portion is provided at multiple locations on the first pipe member and the second pipe member.

[0199] The through holes are formed at the joint portion of the first pipe member.

[0200] According to this joint, since through holes are formed in multiple joints, the vibration distribution of the second pipe member in each joint can be detected individually.

[0201] Furthermore, this application is based on Japanese patent application filed on August 5, 2020 (Japanese Patent Application No. 2020-133198), the contents of which are incorporated herein by reference.

[0202] Explanation of reference numerals in the attached figures

[0203] 11 First Pipe Component

[0204] 13 Second pipe component

[0205] Joints of 15, 15A, 15B, 15C, and 15D

[0206] 17, 17A joint

[0207] 19 through holes

[0208] 21 Excitation Section

[0209] 23 Vibration Testing Department

[0210] 25 Relative Movement Mechanism

[0211] 27 Evaluation Department

[0212] 33 Control Department

[0213] 35 signal generator

[0214] 37 oscillators

[0215] 41Light irradiation department

[0216] 43 Optical Detection Department

[0217] 45 Vibration Distribution Determining Part

[0218] 47 laser source

[0219] 49 beam-forming lenses

[0220] 51 beam splitter

[0221] 53 First reflecting mirror

[0222] 55 Second Reflector

[0223] 57 phase shifter

[0224] 59 Condensing Lens

[0225] 61 Image Sensor

[0226] 63 speckle misalignment interferometer

[0227] 75 overlapping part

[0228] 85-fold section

[0229] 87 Bend

[0230] 91 indentations

[0231] 100 Inspection device (inspection device for joint).

Claims

1. A method for inspecting a joint, wherein a second pipe member having a smaller outer diameter than the first pipe member is inserted into the pipe of a first pipe member having at least one through hole, and the second pipe member is expanded to form a joint. Elastic wave vibration is imparted to the joint of the first and second pipe components. In a field of view that includes the joint of the first and second tube components, measured optically together, the vibration distribution of the first tube component and the vibration distribution of the second tube component measured through the through hole are obtained in multiple field of view regions at different circumferential positions of the joint. The quality of the overall joint is determined based on the obtained vibration distribution.

2. The method for inspecting the joint according to claim 1, wherein, In each of the plurality of said field-of-view regions, The vibration distribution is measured by applying multiple elastic wave vibrations, each with a different position and frequency, to the joint. If all the measured vibration distributions have nodes of a standing wave at the joint, the joint is determined to be well-jointed within the field of view used in the measurement of the vibration distribution.

3. The method for inspecting the joint according to claim 1, wherein, The field of view is illuminated by a flash lamp. By controlling the timing of the elastic wave vibration and the flash lamp illumination, the out-of-plane displacement of each point in the field of view is measured at at least three different phases of the elastic wave vibration, thereby determining the vibration distribution.

4. The method for inspecting the joint according to claim 2, wherein, The field of view is illuminated by a flash lamp. By controlling the timing of the elastic wave vibration and the flash lamp illumination, the out-of-plane displacement of each point in the field of view is measured at at least three different phases of the elastic wave vibration, thereby determining the vibration distribution.

5. The method for inspecting the joint according to any one of claims 1 to 4, wherein, The area around at least the through hole of the first tubular member is formed as a flat surface.

6. An inspection device for a joint, wherein a second pipe member having a smaller outer diameter than the first pipe member is overlapped and joined within the pipe of a first pipe member. The inspection device for the assembly includes: The excitation section imparts elastic wave vibration to the joint body; The vibration detection unit, within a field of view that is optically measured simultaneously and includes the joint of the first and second pipe members, acquires the vibration distribution of the first pipe member and the vibration distribution of the exposed portion of the second pipe member, measured through a through hole formed in the first pipe member, for multiple field of view areas at different circumferential positions of the joint, respectively; and The evaluation unit determines the tightness of the first pipe member and the second pipe member in the joint based on the detected vibration distribution of the exposed portion.

7. The inspection device for the joint according to claim 6, wherein, The vibration detection unit includes: The light irradiation section irradiates a field of view of the first tube component, including at least the through hole, with a laser. The optical detection unit detects the interference pattern formed by the interference of the reflected light from the laser beam in the field of view with a reference light; and The vibration distribution determination unit determines the vibration distribution based on the interference pattern.

8. The inspection device for the joint according to claim 7, wherein, By changing the timing of the elastic wave vibration output by the excitation unit and the timing of the laser irradiation unit irradiating the field of view area, The vibration detection unit measures the displacement of each point in the out-of-plane vibration direction within the field of view at least three different phases of the elastic wave vibration, and calculates the vibration distribution.

9. The inspection device for the joint according to claim 7 or 8, wherein, It also includes a relative movement mechanism that moves the coupling body and the light irradiation part relative to each other to change the irradiation position of the laser from the light irradiation part.

Images