JP4415248B2 - Laser welding apparatus and monitoring method of welded part - Google Patents

Description

  The present invention relates to a laser welding apparatus for laser welding two overlapping members with laser light, and a monitoring method for monitoring a welding state of a welded portion welded by the laser welding apparatus.

  One of the products manufactured by welding two panels is an automobile fuel tank. The fuel tank of an automobile is usually manufactured by welding the outer peripheral edges of two steel plates (panels) with a recessed central portion. In the fuel tank of the first conventional example (see Patent Document 1), the flange portions of the upper half panel and the lower half panel, which are formed by pressing an aluminum-plated steel sheet into a bowl shape, are seam welded.

  The upper half panel and the lower half panel include various accessories. When welding a relatively small accessory part to a relatively large upper panel, conventionally, projection welding or spot welding, which is a type of resistance welding, has been employed. For example, in the fuel tank of the second conventional example (see Patent Document 2), a bezel (auxiliary tank) is spot welded to the lower half panel. Further, in the fuel tank of the third conventional example (see Patent Document 3), the inlet pipe is projection welded to the upper half panel.

  In spot welding, a panel and accessory parts are sandwiched between a pair of electrodes, and a large current flows while applying high pressure. When an appropriate energization time is reached, a melted portion (nugget) is generated at the joint surface between the panel and the accessory part, and the panels are joined together. Projection welding is the case where the projection formed on the accessory part is abutted against the panel.

  By the way, it is difficult to visually confirm whether the two welded members are joined in a predetermined state. Therefore, various nondestructive inspection devices have been developed to inspect the welded state, that is, the quality of the welded portion. For example, in the quality inspection apparatus of the fourth conventional example (see Patent Document 4), the reflected light of the laser beam irradiated toward the welded part of the workpiece is detected by a sensor and converted into an electrical signal. Thereafter, the frequency distribution of the electrical signal is calculated by the measuring device, the signal intensity in a specific frequency band is calculated, and compared with the reference value.

In the quality inspection apparatus of the fifth conventional example (see Patent Document 5), a light emitting unit different from the laser light source is provided on one side of the laser processing head, and the strobe light emitted at the time of low output of the laser light is laser processed. Light is received by a light receiving unit disposed on the other side of the head.
JP 2002-29271 A JP 2002-321537 A JP 2002-239738 A JP 2002-321073 A JP-A-9-174270

  In the fourth conventional example, since the sensor is arranged on the same side as the laser transmitter with respect to the workpiece and detects the reflected light of the laser beam, the laser beam is mixed when the sensor receives the reflected light. However, it is difficult to distinguish between the two, and the quality inspection tends to be inaccurate.

  In the fifth conventional example, a light emitting part different from the laser light and a light receiving part for receiving the light emitted from the light emitting part and reflected by the welding part are arranged for quality monitoring. When forming a welded part that penetrates the upper panel by projection welding to the upper panel, check whether there is a welded part penetrating the molten part or whether there is a welded defect penetrating from the reflected light at the welded part. Is difficult.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a welding apparatus and a monitoring method capable of easily and reliably monitoring the welding state of a welded portion in welding for forming a welded portion that penetrates.

(1) The laser welding apparatus according to the first invention of the present application is arranged on one side of the overlapped member to be welded and the welding member as described in claim 1, and irradiates the superposed portion with the laser beam for welding. A laser beam irradiating means for forming a welded part including a penetration part in which a part of the welded member penetrates a part of the welded member; and a laser beam for welding disposed on one side of the welded member and the welded member A monitor light irradiating means for irradiating the welded portion with monitor light for monitoring the welding state of the welded portion; disposed on the other side of the welded member and the welded member and transmitted through the welded portion A light receiving means for receiving welding laser light and monitor light, and the light receiving means receives the welding laser light transmitted through the weld during irradiation of the welding laser light to confirm formation of the weld. Welding during irradiation of laser beam for welding Performing airtight confirmation of the weld by not receiving the monitor light transmitted through the welded portion after the irradiation of the welding laser beam as well as receiving the transmitted monitor light.

  In this laser welding apparatus, the laser beam for welding irradiated by the laser beam irradiation means melts the overlapped portion, thereby forming a welded portion including a penetration portion where a part of the welding member penetrates a part of the member to be welded. At the time of laser welding, the monitor light irradiating means irradiates the welded portion with monitor light that can be distinguished from the welding laser light from the same side as the laser light irradiating means. The light receiving means receives the welding laser light and the monitor light that have passed through the welded portion on the opposite side of the laser light irradiation means and the monitor light irradiation means. Based on the light reception result, the formation and quality of the weld are determined.

The laser welding apparatus according to claim 2 is the laser welding apparatus according to claim 1, wherein the monitor light irradiated by the monitor light irradiation means is monochromatic light. According to a third aspect of the present invention, in the laser welding apparatus according to the first aspect, the light receiving means includes a laser light receiving portion and a monitor light receiving portion that are arranged apart from each other. A laser welding apparatus according to a fourth aspect is the laser welding apparatus according to the first aspect, wherein the light receiving means has a common light receiving portion for receiving both the welding laser light and the monitor light.
(2) According to a second aspect of the present invention, the method for monitoring a welded portion is characterized in that welding laser light is irradiated to the overlapped portion from one side of the welded member and the welded member superimposed, and welding is performed. A method for monitoring a welding state of a welded part when forming a welded part including a penetration part in which a part of the member penetrates a part of a member to be welded. A first step of irradiating the welded portion from one side of the member to be welded and the welded member with a wavelength different from that of the welded portion, and welding the welded laser beam and the monitor light And a second step of detecting the passing of the welding part on the other side of the welded member and the welding member, and the light receiving means receives the welding laser beam transmitted through the welding part during irradiation of the welding laser beam. To confirm the formation of the welded part Airtight confirmation of the welded portion is performed by receiving monitor light that has passed through the weld during light irradiation and not receiving monitor light that has passed through the weld after being irradiated with laser light for welding.

  In this method for monitoring a welded portion, when laser welding is performed, monitor light that can be distinguished from the laser beam for welding in the first step is irradiated to the welded portion from the same side as the laser beam for welding. In the second step, the welding laser light and the monitor light that have passed through the welded portion are received on the side opposite to the side where the welding laser light and the monitor light are irradiated. Based on the light reception result, the formation and quality of the weld are determined.

  According to a sixth aspect of the present invention, in the first step of the fifth aspect, the monitor light applied to the welded portion is monochromatic light. According to a seventh aspect of the present invention, in the second step of the fifth aspect, in the second step of the fifth aspect, the formation of the weld is determined based on the passage of the laser beam for welding by the light receiving means, and the airtightness at the weld is determined based on the passage of the monitor light. Determine.

(1) According to the laser welding apparatus of the first invention of the present application, the welded member and the welded member can be reliably laser-welded while managing the quality of the welded portion that has penetrated. According to the laser welding apparatus of the second aspect, since the monitor light is monochromatic light, the monitor light is reliably identified by the light receiving means. According to the laser welding apparatus of the third aspect, since the light receiving part for welding laser light and the light receiving part for monitor light are separated from each other, the laser light for welding and the monitor light can be more reliably distinguished in the light receiving means. According to the laser welding apparatus of the fourth aspect, since the common light receiving part receives both the welding laser beam and the monitor light, the light receiving means can be simplified.
(2) According to the method for monitoring a welded portion of the second invention of the present application, the welding state of the welded portion in which the welding member is laser-welded to the member to be welded can be reliably monitored. This is because the passage of the welding laser beam through the welded portion, that is, the formation of the penetration portion is confirmed, and the passage of the monitor light through the welded portion, that is, the presence of a small hole in the welded portion is confirmed. Further, the passage of the monitor light irradiated from the same side as the welding laser beam is detected by the light receiving means on the opposite side to the welding laser beam.

  According to the method for monitoring a welded portion of claim 6, since the monitor light is monochromatic light, the monitor light is reliably identified by the light receiving means. According to the method for monitoring a welded portion of claim 7, the welding laser beam that has passed through the welded portion is detected by the light receiving means to confirm the formation of the through portion, and the monitor light that has passed through the welded portion is detected by the light receiving means. As the airtightness at the weld is confirmed, the welding status can be monitored more reliably.

<Welded member, welded member>
There are no particular restrictions on the shape of the member to be welded which is one of the members welded to each other by the laser welding apparatus of the present invention and the shape of the welding member which is the other, and may be a plate shape or a rod shape.

A part of the member to be welded and a part of the welding member are overlapped with each other, and a laser beam for welding (hereinafter abbreviated as “laser light” as necessary) is irradiated to the overlapped portion from the side of the welding member. Then, a part of the welding member penetrates a part of the member to be welded in a nested manner, and a welding part including the penetration part is formed. Examples of the member to be welded and the welding member include an upper panel and its accessory parts that constitute a fuel tank of an automobile, or a lower panel and its accessory parts.

  The fuel tank is formed by welding an upper panel having an upper depression and a lower panel having a lower depression at an outer peripheral flange portion. (Preferably both flanges are laser welded.) The shape of the accessory laser welded to the panel can be rod-shaped, annular or bracket-shaped. The size of the accessory is smaller than the size of the panel (1/10 to 1/10), and the thickness is thinner than the panel (about 1/10).

Specific examples of accessory parts laser welded to the upper panel include a pump retainer, an inlet, a breather tube, and a separator, and accessory parts laser welded to the lower panel include a sub tank.
<Laser welding equipment>
The laser welding apparatus of the present invention includes a monitor light irradiation means and a light receiving means for monitoring the welding state of the welded part, in addition to the laser light irradiation means directly involved in laser welding.
a. Laser light irradiation means The laser light irradiation means is arranged on one side (welding member side) in the plate thickness direction with respect to the member to be welded and the welding member partially overlapped with each other, and the overlapping portion from one side Is irradiated with a laser beam for welding. The location can be in the vicinity of the weld, for example just above it.

Laser welding (keyhole welding), which is a kind of fusion welding, is performed by the laser light emitted by the laser light irradiation means. The portion irradiated with the laser light is melted, and a penetration portion is formed in which a part of the welding member penetrates a part of the welded portion in a nested manner. The type of laser light is not questioned, and a YAG laser or a CO ₂ laser may be used.
b. Monitor light irradiating means The monitor light irradiating means is disposed on the one side, that is, on the same side as the laser light irradiating means, and has a wavelength different from that of the welding laser light and is used for monitoring the welding state by the welding laser light. To the weld. The monitor light emitted by the monitor light irradiation means is preferably monochromatic light, that is, a single wavelength. One monochromatic light source can be arranged immediately above the welded portion, or two monochromatic light sources can be arranged obliquely above and to the left and right of the welded portion.

As monochromatic light having a single wavelength, sodium light or xenon light can be used. The single wavelength is used for distinction from the laser light, and the monochromatic light is used for easy identification.
c. Light receiving means The light receiving means is disposed on the other side of the welded member and the welding member, that is, on the opposite side of the laser light irradiation means and the monitor light irradiation means, and receives the welding laser light and the monitor light that have passed through the welded portion. The laser light receiving unit and the monitor light receiving unit that are arranged apart from each other may be included, or a common (one) light receiving unit that receives both the welding laser beam and the monitor light may be included.

In the former, the laser light receiving part is arranged on a straight extension line connecting the laser light source and the welding part, and the monitor light receiving part is arranged on a straight extension line connecting the monitor light source and the welding part. In the latter case, the common light receiving unit is disposed at a position where both the laser light and the monitor light can be received. Even in this case, the laser light and the monitor light have different wavelengths, and therefore can be distinguished by spectrum analysis or the like. The light receiving means corresponds to the sensor system of the laser welding apparatus, and the light reception result is processed by the processing system.
<Monitoring method for welds>
a. Premises The method for monitoring a welded portion of the present invention is a method for monitoring the welding state of a penetration type (nested type) welded portion formed by the laser welding apparatus, that is, a method for inspecting the quality of the welded portion. During laser welding, defects such as penetration defects, blowholes (small holes, gaps), and weld cracks that may occur in the welded portion are inspected.

Specifically, during laser welding, a welding member (for example, an accessory) is first placed on a member to be welded (for example, a panel). Next, a laser beam is irradiated toward the member to be welded from one side (side of the member to be welded). Then, the laser beam proceeds while making a keyhole in the member to be welded and the welding member, and these molten metals fill the keyhole. When the filled molten metal is solidified, a welded portion is formed in which the penetrating portion extending from the member to be welded penetrates a part of the welding member in the thickness direction.
b. Monitoring device for welded portion The monitoring device includes at least monitor light irradiating means for irradiating the welded portion with monitor light, and light receiving means for receiving laser light and monitor light. In order to determine the quality of welding by monitoring the welding state of the welded part during laser welding, at least the following two steps are executed.
c. 1st process 1st process has a wavelength different from welding laser light at the time of irradiation with laser light for welding, monitors light for monitoring a welding state of a welding part by laser light for welding, a member to be welded and welding Irradiate the weld from one side of the member. That is, at the time of laser welding, the passage of the laser beam at the welded portion is detected by the light receiving means disposed on the opposite side of the laser light source with respect to the welded member. In other words, it can be regarded as a step of confirming the formation of the welded portion including the nested penetrating portion.

  At that time, the laser light source can be disposed directly above the welding member (accessory), and the light receiving means can be disposed directly below the member to be welded.

Since the laser beam advances while melting a part of the welding member (accessory part) and the member to be welded (panel), when the molten part penetrates the molten part of the panel, the laser beam It penetrates the panel and reaches the side opposite to the laser light source. Therefore, the formation of the welded portion including the penetrating portion can be confirmed by detecting the penetration of the laser beam by the light receiving means.
d. Second Step The second step detects the passage of the welding laser light and the monitor light at the welded portion on the other side of the welded member and the welding member during irradiation of the welding laser light and the monitor light. In other words, the light-receiving means allows the monochromatic light source disposed on the same side as the laser light source to be welded and the welding member to emit through the welded portion of the monochromatic light having a wavelength different from that of the laser beam emitted toward the welded portion. Detect. In other words, it can be regarded as a process for confirming the quality of penetration such as the formation of blow holes (airtightness of the welded portion). This monochromatic light is not related to the melting of accessory parts and panels. When a monitor (monochromatic light) from the monitor light source is received by the light receiving means, a small hole or the like exists in the welded portion.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In this embodiment, the present invention is applied to laser welding of accessories to a fuel tank panel of an automobile.
(Fuel tank)
1 to 5 show the fuel tank. 1 is a perspective view before welding of the upper panel of the fuel tank, FIG. 2 is a perspective view after welding of the upper panel, FIG. 3 is a perspective view before welding of the lower panel, FIG. 4 is an explanatory view showing welding and quality inspection, FIG. 5 is an enlarged view of the main part (welded part) of FIG. As shown in FIGS. 1 and 2, the upper panel 10 has an upper recess 11 projecting upward (indented) at a central portion thereof, and an upper flange portion 12 at an outer periphery thereof. A pump retainer 14 is laser welded to the upper surface of the ceiling 13 of the upper recess 11, and a separator 17 is laser welded to the lower surface. An inlet 17 and a breather tube 18 are laser welded to corners of the upper recess 11.

  As shown in FIG. 3, the lower panel 20 has a lower recess 21 projecting downward (indented) at the center thereof, and a lower flange portion 22 on the outer periphery. The sub tank 24 is laser welded to the bottom of the lower recess 21, the lower flange portion 22 and the upper flange portion 12 are laser welded, and the upper recess 11 and the lower recess 21 define a fuel accommodation space.

As shown in FIG. 4, the pump retainer 14 includes an annular portion 15a and a flange portion (overlapping portion) 15b on the lower end side thereof, and the flange portion 15b is welded to the upper surface of the ceiling portion 13 by laser welding. Specifically, as shown in FIG. 5, a penetrating portion 16 projecting downward from the lower surface of the flange portion 15 b penetrates the ceiling portion 13 in the thickness direction. The front end (lower end) of the penetrating part 16 reaches the lower surface 13 a of the ceiling part 13.
(Laser welding equipment)
As can be seen from FIGS. 5 and 6, the laser welding apparatus includes a panel device table 31, a panel positioning device 32, a YAG laser light laser torch 30, a pair of sodium lamps 35 a and 35 b, and photodiodes 37 to 39. The laser torch 30 is disposed immediately above the center of the upper panel 10, and a pair of sodium lamps 35a and 35b are disposed on both sides thereof, that is, diagonally above and to the left and right of the welded portion 26, and have a single color and a single wavelength (0.589 μm). Sodium light is emitted toward the welded portion 26.

  On the lower side of the pump retainer 14 and the upper panel 10, a YAG laser light receiving photodiode (first light receiving portion) 37, which is a photovoltaic element, is disposed immediately below the welded portion.

  In addition, a photodiode (second light receiving portion) 38 for receiving sodium light is disposed at a position facing one sodium lamp 35 with the welded portion 16 in between, that is, diagonally below the left and right of the welded portion. These photodiodes 37 and 38 generate an electrical signal corresponding to the amount of light received when YAG laser light and sodium light that have passed through the welded portion 26 are received.

In this embodiment, a CCD camera 39 is further set at a position facing the other sodium lamp 35b with the welded portion 26 in between. The CCD camera 39 forms an image corresponding to the amount of light received when receiving YAG laser light and sodium light that have passed through the welded portion 26.
(Laser welding method)
The welding method will be described with reference to FIGS. FIG. 6 is a perspective view showing the welding robot, and FIG. 7 is an explanatory diagram of the entire quality inspection system. First, as shown in FIGS. 4 and 6, the upper panel 10 is set on the panel device table 31 so that the opening of the upper recess 11 faces downward, and the positioning mechanism 32 pumps the upper panel 10 to a predetermined position on the upper surface of the ceiling portion 13. The collar portion 15b of the retainer 14 is positioned.

Next, YAG laser light (wavelength: 1.065 μm) is irradiated downward from the laser torch 30 set right above the pump retainer 14 toward the pump retainer 14. The YAG laser light then melts the pump retainer 14 and the upper panel 10 while melting the ceiling 13 to form a keyhole, and the keyhole is filled with a molten material. At that time, the upper panel 10 and the pump retainer 14 are rotated and moved by the positioning mechanism 32 as necessary. Thus, the penetration part 16 of the collar part 15 b penetrates the ceiling part 13 in the plate thickness direction, and the pump retainer 14 is laser-welded to the upper panel 10 by the welding part 26 including the penetration part 16.
(Monitoring the welding state of the weld)
(A) Welding state monitoring device As described above, the monitoring of the welding state of the welded portion 26 is, in other words, an inspection of the quality of the welded portion 26. First, a welding state monitoring device (quality inspection device) will be described. As shown in FIGS. 4 and 7, the quality inspection apparatus is roughly divided into a sensor system 45, a control system 50, and a data processing system 55.

  Among these, the sensor system 45 includes a YAG laser light receiving photodiode 37, a sodium light receiving photodiode 38, and a CCD camera 39. These have been described in the section of the laser welding apparatus.

The control system 50 in FIG. 7 includes a diode control unit 51 and a camera control unit 52. The photodiodes 37 and 38 are connected to the diode controller 51, and the CCD camera 39 is connected to the camera controller 52. The data processing system 55 includes an image input unit 56, an A / D conversion unit 57, and an analysis unit 58. The image input unit 56 receives image information from the camera control unit 52, and the A / D conversion unit 57 converts the analog signal from the diode control unit 51 into a digital signal. The analysis unit 58 performs overall system control, data input processing, data analysis, and host system communication.
(B) Monitoring Method of Welding State Next, a state monitoring method (quality inspection method) of the welded portion 26 will be described. This embodiment employs a specific quality inspection method in relation to the adoption of laser welding for welding the pump retainer 14 to the upper panel 10, and the first step (the formation confirmation step of the through portion 16), It is roughly divided into a second process (an airtight confirmation process of the welded portion 26).
a. First, as a step for confirming the formation of the through portion 16, the passage of YAG laser light in the welded portion 26 was detected by one photodiode 37 and the CCD camera 39 during laser welding. As a result, as shown in FIG. 8A, a bright spot appeared near the center of the photograph taken from the lower surface side of the upper panel 10. Further, as shown in FIG. 8B, the voltage of the photodiode 37 is substantially zero before the start of welding, becomes intermittently considerably high during welding (during irradiation with YAG laser light), and is substantially zero after the end of welding. Became. Further, as shown in FIGS. 9B and 9C, in the CCD camera 39, the luminance signal becomes very high during welding in both the X-axis direction and the Y-axis direction. As a result, the screen as shown in FIG. An almost circular luminescent spot appeared in the center of.

From this, it can be seen that the YAG laser beam passes through the welded portion 26 during laser welding. As described above, the irradiated YAG laser light travels while forming keyholes in the pump retainer 14 and the panel 10. Therefore, the YAG laser beam penetrating the ceiling portion 13 means that the molten metal of the collar portion 15 and the ceiling portion 13 has reached the lower surface 13 a of the ceiling portion 13.
b. Next, as a process for confirming the airtightness of the welded portion 26, the passage of sodium light emitted from the pair of sodium lamps 35 a and 35 b to the welded portion 26 is detected by the photodiode 38 and the CCD camera 39 from the time of laser welding to the end. did. As a result, as shown in FIG. 10A, a bright spot appeared near the center of the photograph taken from the lower surface side of the upper panel 10. In addition, as shown in FIGS. 11B and 11C, in the CCD camera 39, the luminance signal instantaneously increased during welding in both the X-axis direction and the Y-axis direction. However, as shown in FIG. The point did not appear. Furthermore, as shown in FIG. 10 (b), the voltage of the photodiode 38 was slightly increased as a whole during welding, and decreased before the start of welding and after the end of welding.

  As a result, sodium light passes through the welded portion 26 during welding, but does not pass through the welded portion 26 after the end of welding (after irradiation of YAG laser light), that is, a small hole or the like in the welded portion 26. It can be seen that is not formed.

In addition, when the strength check of the welding part 26 is detected in the formation confirmation process of the penetration part 16, you may cancel the airtight confirmation process of the welding part 26. FIG. In other words, the airtightness inspection is based on the premise that a desired strength is ensured.
(effect)
According to this embodiment, the following effects can be obtained in the laser welding apparatus and the quality inspection method for the welded portion.
(A) Laser welding apparatus Welding of the accessory parts 14 and 24 to the panels 10 and 20 is reliable. Laser welding or the like to the upper panel 10 of the pump retainer 14 is ensured because the laser welding apparatus includes sodium lamps 35a and 35b, photodiodes 37 and 38, and a CCD camera 39. This is because welding was performed while inspecting.

If welding of the lower panel 20 and the upper panel 10 is performed by laser welding, welding of the entire fuel tank can be unified with laser welding. That is, the welding robot shown in FIG. 6 can perform laser welding of the upper panel 10 and its accessory part 14, laser welding of the lower panel 20 and its accessory part 24, and laser welding of the panels 10 and 20. .
(B) Quality inspection method A reliable quality inspection of the welded portion 26 is possible. One reason is that both the formation of the penetration 16 and the presence of small holes in the weld 26 are inspected. More specifically, since the melted material is inserted into the laser welding keyhole, it is important to confirm that the molten metal has penetrated the ceiling portion 13 of the upper panel 10 in determining the quality of the welded portion 26. is there. On the other hand, the formation of keyholes may lead to the formation and remaining of small holes. Therefore, the penetration of the YAG laser beam through the welded portion 26 is inspected, that is, the strength of the welded portion 26 is inspected, and the airtightness is inspected by the passage of sodium light through the welded portion 26.

  Another reason is that the photodiodes 37 and 38 and the CCD camera 39 are disposed on the opposite side of the upper panel 10 from the laser torch 30 and the sodium lamps 35a and 35b. That is, instead of the reflected light as in the conventional example, the quality is inspected using the penetrating light in this embodiment. When the through portion 16 is formed, the YAG laser beam passes through the welded portion 26, and when the small hole remains, the sodium light passes through the welded portion 26. The presence or absence of passing of YAG laser light or sodium light is detected by the photodiodes 37 and 38 and the CCD camera 39 arranged below the upper panel 10.

  It should be noted that it is not easy to reliably inspect the quality of the laser welded portion 26 in the fourth or fifth embodiment. These conventional examples use reflected light that is reflected by a laser beam or other light at the weld, but it is difficult to detect the formation of the through-hole 16 and the presence of small holes from the analysis of the reflected light.

  Another reason is that two sodium lamps 35a and 35b are provided, and the sodium light is received by the photodiode 38 and the CCD camera 39, so that the presence of the small holes can be detected even if they are unevenly distributed. Further, the fact that the YAG laser light is received by the CCD camera 39 that originally receives sodium light and the sodium light is also received by the photodiode 37 that originally receives YAG laser light contributes to higher-level inspection results.

It is a perspective view before welding of the upper panel of a fuel tank. It is a perspective view after welding of an upper panel. It is a perspective view before welding of a lower panel. It is explanatory drawing which shows welding and a quality inspection. It is a principal part (welded part) enlarged view of FIG. It is a perspective view which shows a welding robot. It is explanatory drawing of the whole quality inspection system. (A) is the photograph which image | photographed passage of a laser beam, (b) is a graph which shows reception of the YAG laser beam by a photodiode. (A) is an image figure which shows reception of the YAG laser beam by a CCD camera, (b) is a graph which similarly shows a signal. (A) is the photograph which image | photographed passage of sodium light, (b) is a graph which shows the received signal of sodium light by a photo diode. (A) is an image figure which shows reception of the sodium light by a CCD camera, (b) is a graph which similarly shows a signal.

Explanation of symbols

10: Upper panel 11: Upper indentation 12: Upper flange 13: Ceiling part 14: Pump retainer 15b: Brim part 16: Through part 20: Lower panel 26: Welding part 30: Laser torch 35a, 35b: Sodium lamp 37, 38: Photodiode 39: CCD camera

Claims (6)

Arranged on one side of the welded member and the welded member that are overlapped, the overlapped portion is irradiated with a laser beam for welding, and a part of the welded member includes a through portion that penetrates a part of the welded member A laser beam irradiation means for forming a weld;
Monitor light that is disposed on one side of the welded member and the welded member, has a wavelength different from that of the welding laser beam, and irradiates the welded portion with monitor light for monitoring the welding state of the welded portion. Irradiation means;
A light receiving means that is disposed on the other side of the welded member and the welding member and receives the laser beam for welding and the monitor light transmitted through the welded portion ;
The light receiving means receives the welding laser beam that has passed through the welding portion during irradiation of the welding laser beam, thereby confirming formation of the welding portion, and performs the welding during the irradiation of the welding laser beam. A laser welding apparatus characterized by receiving the monitor light transmitted through a part and checking the airtightness of the welded part by not receiving the monitor light transmitted through the welded part after irradiation of the welding laser light .   The laser welding apparatus according to claim 1, wherein the monitor light irradiated by the monitor light irradiation means is monochromatic light.   2. The laser welding apparatus according to claim 1, wherein the light receiving means includes a laser light receiving unit and a monitor light receiving unit that are arranged apart from each other.   2. The laser welding apparatus according to claim 1, wherein the light receiving means has a common light receiving portion for receiving both the welding laser light and the monitor light. A welded portion including a welded portion including a welded portion irradiated with a laser beam for welding from one side of the overlapped welded member and the welded member, and a part of the welded member penetrating a part of the welded member. A method of monitoring the welding state of the weld when forming,
When irradiating the welding laser beam, a monitor light is emitted from one side of the welded member and the welding member to monitor the welding state of the welded portion and has a wavelength different from that of the welding laser beam. A first step of irradiating
A second step of detecting passage of the welding laser beam and the monitor beam at the welded portion on the other side of the welded member and the welded member, and
The light receiving means receives the welding laser beam that has passed through the welding portion during irradiation of the welding laser beam, thereby confirming formation of the welding portion, and performs the welding during the irradiation of the welding laser beam. Monitoring the welded portion, wherein the welded light is confirmed by not receiving the monitor light that has passed through the welded portion and not receiving the monitor light that has passed through the welded portion after being irradiated with the laser beam for welding. Method.   The monitoring method for a welded portion according to claim 5, wherein the monitor light irradiated on the welded portion in the first step is monochromatic light.

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