JP2010207840A - Laser beam welding equipment and laser beam welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser beam welding equipment that reduces cost required for preventing an oxide film from being produced, by forming an inert atmosphere around a weld zone without using a gas for shielding and thereby preventing production of the oxide film, and to provide a laser beam welding method. <P>SOLUTION: In the laser beam welding equipment, a sidewall part 64 that is arranged while covering the periphery of a weld zone 230 of welding members and an opening part 65 that is continuous to the sidewall part and that passes the laser beam which irradiates the weld zone, are formed. The equipment is provided with a cylindrical member 60 having a sufficient volume for filling vapor generated from the weld zone by welding. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser welding apparatus and a laser welding method.

  There is known a laser welding method in which a laser is irradiated on a welding member to weld the welding member. The laser welding method irradiates the welded portion of the welded member with laser and melts the welded member. However, when the laser is irradiated with the welded portion exposed to the atmosphere, the welded portion takes in oxygen and cools the oxide film. May occur.

  A coating process for forming a coating film for the purpose of rust prevention is generally performed on the welded member after welding. In the welded portion where the oxide film is generated, the adhesion of the coating film is lowered, so that the coating film is easily peeled off, and the quality of the welded member may be deteriorated.

  In the invention described in Patent Document 1, laser welding is performed while blowing a shielding gas around the welded portion, thereby preventing an oxide film from being generated in the welded portion (see Patent Document 1). reference).

JP-A 57-56190

  In the above invention, although an oxide film can be prevented from being generated in the welded portion, there is a problem that the cost required for laser welding increases due to the use of a shielding gas.

  Accordingly, the present invention provides a laser welding apparatus and laser welding that prevent the occurrence of an oxide film on a welded portion without using a shielding gas during laser welding and reduce the cost required to prevent the formation of an oxide film. It aims to provide a method.

  The laser welding apparatus of the present invention has a cylindrical shape in which a side wall portion that covers and arranges the periphery of a welded portion of a welding member, and an opening portion that is connected to the side wall portion and allows a laser irradiated to the welded portion to pass therethrough. It has a member. The tubular member has a volume that can be filled with steam generated from the welded portion during welding.

  The laser welding method of the present invention is performed by covering the periphery of the welded portion of the welding member with a container. Laser is irradiated to the welded portion in a state where the welded portion is covered with the container.

  According to the present invention, a laser beam is irradiated to the welded portion covered by the side wall portion of the cylindrical member, and the steam generated by the laser irradiation is ejected to the outside of the cylindrical member. An inert atmosphere can be formed around the weld without using gas, and the cost required to prevent the formation of an oxide film can be reduced.

It is a figure which simplifies and shows the laser welding apparatus which concerns on this embodiment. It is a figure for demonstrating a cylindrical member. FIGS. 3A and 3B are diagrams for explaining the principle of preventing the generation of an oxide film using a cylindrical member. FIGS. 4A and 4B are views for explaining the principle of preventing the generation of an oxide film using a cylindrical member. FIGS. 5A to 5C are diagrams for explaining a method of arranging the cylindrical members. FIGS. 6A and 6B are diagrams for explaining examples of the shape of the cylindrical member. FIGS. 7A and 7B are diagrams for explaining the laser welding method, and are views seen from the direction of arrow 7A in FIG. FIG. 8 is a view for explaining a cylindrical member according to the first modification. FIGS. 9A and 9B are views for explaining a cylindrical member according to the second modification. 10A and 10B are diagrams for explaining the conditions of the example. FIG. 11 is a diagram illustrating an implementation result of the first embodiment. FIG. 12 is a diagram illustrating an implementation result of the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of explanation, and may be different from the actual ratios.

  FIG. 1 shows a laser welding apparatus 100 according to the present embodiment. In this embodiment, the laser welding apparatus and the laser welding method of the present invention are the steel plates 210 and 220 arranged on the mounting table 80 as the welding member 200, and the welding member 200 is irradiated with the laser. Thus, the present invention is applied to a laser welding apparatus 100 that performs welding and a laser welding method.

  Referring to FIG. 1 and FIG. 2, the laser welding apparatus 100 will be briefly described. The side wall portion 64 disposed so as to cover the periphery of the welded portion 230 of the welding member 200, and the welded portion 230 connected to the side wall portion 64. And the cylindrical member 60 having a volume capable of filling the vapor V generated from the welded portion 230 during welding (see also FIG. 7A). ). The side wall portion 64 of the cylindrical member 60 is formed so as to extend along the laser irradiation direction with respect to the welded portion 230 (see also FIG. 5C). The laser welding apparatus 100 clamps the welding member 200 by placing the tubular member 60 against the welding member 200.

  The welding part 230 in this specification means the site | part which irradiates the welding member 210,220 with a laser in order to weld the welding member 210,220, and its peripheral part. Hereinafter, this embodiment will be described in detail.

  Referring to FIGS. 1 and 2, laser welding apparatus 100 includes laser welding robot 10 that performs laser welding by irradiating welding member 200 with a laser, and a cylinder that is disposed so as to cover the periphery of welded portion 230. And a control unit 40 that controls the operation of each part of the laser welding apparatus 100, and a laser oscillator 50 that oscillates a laser.

  The laser welding robot 10 includes a laser processing head 20 that irradiates a laser beam transmitted from the laser oscillator 50 to the welded portion 230, and a robot arm 30 that moves the laser processing head 20 to a predetermined position. ing. An optical fiber 35 is used for laser transmission from the laser oscillator 50 to the laser processing head 20. In each figure, the laser L irradiated from the laser processing head 20 is indicated by a broken line.

  The laser processing head 20 includes a lens group 21 for converging and irradiating the transmitted laser beam to the welded portion 230, and a rotatable optical mirror 22. The laser transmitted from the optical fiber cable 35 into the laser processing head 20 passes through the lens group 21 and enters the optical mirror 22. The optical mirror 22 is rotated by a driving source (not shown) and scans the laser along a predetermined welding locus. The laser is scanned along an arbitrary welding locus such as an elliptical shape (see FIG. 7A), a circular shape, or a linear shape.

  The robot arm 30 is a general multi-indirect robot arm 30. The laser processing head 20 arranged at the tip is moved in various directions according to the operation given by the teaching work. It is possible to irradiate the laser along the welding trajectory determined by moving the robot arm 30.

  The tubular member 60 is arranged to place the tubular member 60 on the welding member 200 (indicated by an arrow c in FIG. 1) or to retract from the welding member 200 (indicated by an arrow c ′ in FIG. 1). An arm portion 69 is attached. The operation of the arm unit 69 is driven by a driving robot (not shown).

  Referring to FIG. 2, cylindrical member 60 has a cylindrical outer shape having a side wall portion 64, and a first opening 66 and a second opening 67 connected to side wall portion 64. Yes. The surface shape of the first opening 66 is circular, and the surface shape of the second opening 67 is elliptical (see FIG. 6A).

  The arm portion 69 is operated to place the tubular member 60 on the welding member 200. The arm portion 69 presses the tubular member 60 against the welding member 200 (the pressing is indicated by an arrow P in the figure). The cylindrical member 60 is arranged without forming a gap between the ground contact surface of the second opening 67 and the welding member 200 by pressing with the arm portion 69. The tubular member 60 is covered by the side wall portion 64 so as to surround the periphery of the welded portion 230.

  The cylindrical member 60 clamps the first and second welding members 210 and 220 by being pressed against the welding member 200. By adding the function of clamping the welding member 200 to the tubular member 60, the placement of the tubular member 60 and the clamping of the welding member 200 can be performed simultaneously, and the work efficiency of the placement work of the tubular member 60 is improved. be able to. Compared with the case where the clamping device is provided separately, the manufacturing cost of the device can be reduced.

  The structure of the arm portion 69 is not limited to that shown in the figure, and can be appropriately changed in a form in which the tubular member 60 can be pressed against the welding member 200.

  During laser welding, a laser is incident from the first opening 66 side in a state of surrounding the welded portion 230. The laser beam is irradiated to the welded portion 230 through the first opening 66, the internal space 68 of the cylindrical member 60, and the second opening 67. The welding member 200 is melted by the heat applied by the laser irradiation. Laser is irradiated along a predetermined welding locus to form a weld bead 240. When the welded portion 230 irradiated with the laser solidifies, the welding is finished.

  By performing laser welding using the cylindrical member 60, it is possible to prevent an oxide film from being generated on the weld bead 240. The principle for preventing the generation of an oxide film will be described.

  With reference to FIG. 3 (A), laser is irradiated to welded portion 230 in a state in which cylindrical member 60 is disposed on a steel plate as member to be welded 200.

  Referring to FIG. 3 (B), a local temperature rise occurs at the site irradiated with laser, and welding member 200 evaporates to generate metal vapor V. The welded portion 230 irradiated with the laser evaporates while consuming atmospheric oxygen present in the periphery while being melted. The vaporized metal vapor V fills the cylindrical member 60 and the pressure in the internal space 68 of the cylindrical member 60 increases. A pressure difference is generated between the internal space 68 of the cylindrical member 60 and the outside. Due to this pressure difference, a flow of the steam V toward the first opening 66 is generated.

  The side wall 64 exhibits a function of directing the metal vapor V generated on the second opening 67 side to the first opening 66 side with directivity.

  Referring to FIG. 4A, metal vapor V is jetted out of cylindrical member 60 from first opening 66 together with oxygen remaining in internal space 68 of cylindrical member 60. The oxygen concentration in the internal space 68 of the cylindrical member 60 is reduced, and an inert atmosphere in which no oxygen is present is formed around the welded portion 230.

  The pressure in the internal space 68 of the cylindrical member 60 decreases with the ejection of the metal vapor V and oxygen.

  The welded portion 230 irradiated with the laser is cooled and solidified in an inert atmosphere. Since it solidifies without taking in oxygen, it can prevent that an oxide film generate | occur | produces in the weld bead 240. FIG.

  With reference to FIG. 4 (B), air a in the atmosphere gradually flows into the internal space 68 of the cylindrical member 60 in a state where the pressure is lowered. The welded portion 230 irradiated with the laser is cooled and solidified before the air a flows after being irradiated with the laser, and is removed from the temperature range where oxygen is taken in. For this reason, generation | occurrence | production of the oxide film which can arise with the oxygen contained in the inflowing air a can be prevented.

  When laser welding is performed in a state where a gap is generated between the welding member 200 and the ground contact surface of the second opening 67, the generated steam V leaks from the gap and the steam V ejected from the first opening 66. Will lose momentum. In such a case, there exists a possibility that the effect which prevents generation | occurrence | production of an oxide film cannot fully be exhibited. By placing the tubular member 60 against the welding member 200, it is possible to prevent a gap from being generated, and it is possible to more reliably prevent the generation of an oxide film.

  Generally, a coating process for forming a coating film for the purpose of preventing rust or the like is performed on the welded member after welding. When a coating film is formed on the weld bead in which the oxide film is generated, the adhesion of the coating film is lowered and the coating film is easily peeled off. The peeling of the coating film formed on the entire welded member starts from the peeling of the coating film generated in the weld bead, and there is a possibility that the quality of the welded member after welding is deteriorated.

  As described above, by performing laser welding using the tubular member 60, it is possible to prevent the generation of an oxide film on the weld bead 240, and the weld member 200 after welding that can be generated along with the generation of the oxide film. It becomes possible to prevent the deterioration of quality.

  Next, the suitable shape of the cylindrical member 60 utilized for laser welding is demonstrated.

  With reference to FIG. 5 (A), when welding member 200 having a shape as shown in the figure is clamped by clamp means 70 and welding is performed by irradiating laser to welded portion 230 indicated by a broken line, welding is performed. When the laser is irradiated perpendicularly to the portion 230, the clamp means 70 arranged on the optical path of the laser and the laser interfere with each other. In such a case, it is possible to irradiate the welded portion 230 with a laser without causing interference with the clamping means 70 by irradiating the laser with an inclination with respect to the surface to be irradiated with the laser.

  Referring to FIG. 5B, when cylindrical member 60 having a shape extending in a direction orthogonal to the laser irradiation surface is used, cylindrical member 60 and the laser interfere with each other, so that welded portion 230 is obtained. It becomes difficult to irradiate with laser welding.

  Referring to FIG. 5C, if a cylindrical member 60 having a shape in which the side wall portion 64 extends along the laser irradiation direction is used, the welded portion 230 can be prevented from interfering with the cylindrical member 60. Laser irradiation can be performed. Thus, even when the laser irradiation angle is restricted by the shape of the welding member 200 or the clamp means 70 disposed on the welding member 200, the side wall portion having a shape that matches the laser irradiation angle. By forming 64, the cylindrical member 60 can be suitably used for laser welding.

  6A and 6B, when the cylindrical member 60 is disposed to be inclined with respect to the welding member 200, the first shape is set in accordance with the shape of the welded portion 230 and the laser irradiation locus. It is desirable to change the shape of the second openings 66 and 67 as appropriate.

  By forming the surface shape of the first opening 66 in a circular shape and the surface shape of the second opening 67 in an oval shape, the cylindrical member 60 can be formed without generating a gap with the welding member 200. Can be arranged (see FIG. 6A).

  For example, the surface shape of the first opening 66 may be formed in an elliptical shape, and the surface shape of the second opening 67 may be formed in a circular shape (see FIG. 6B).

  The surface shapes of the first and second openings 66 and 67 are not limited to the illustrated shapes, and can be appropriately changed according to the laser irradiation angle, the shape of the welding member and the welded portion, and the like. It is.

  Next, the operation will be described.

  With reference to FIG. 7A, the cylindrical member 60 is arranged so that the periphery of the welded portion 230 is surrounded by the side wall portion 64 during laser welding. At this time, the tubular member 60 is arranged so that no gap is generated between the welding member 200 and the ground contact surface of the second opening 67.

  The arm portion 69 clamps the welding member 200 by pressing the tubular member 60 against the welding member 200.

  Laser is irradiated to the welded portion 230 in a state where the cylindrical member 60 is disposed. Since the side wall portion 64 is formed in a shape that extends along the laser irradiation direction, the laser can be irradiated without causing the cylindrical member 60 to interfere. The laser irradiates along a welding locus set in accordance with the surface shape of the second opening 67.

  The welded portion 230 irradiated with the laser evaporates while consuming atmospheric oxygen present in the periphery while being melted, and generates a metal vapor V. The vaporized metal vapor V fills the cylindrical member 60 and the pressure in the internal space 68 of the cylindrical member 60 increases. A pressure difference is generated between the internal space 68 of the cylindrical member 60 and the outside. Due to the pressure difference, a flow of steam V toward the first opening 66 occurs.

  The metal vapor V is ejected from the first opening 66 toward the outside of the cylindrical member 60. At this time, oxygen remaining in the internal space 68 of the cylindrical member 60 is ejected together.

  The side wall portion 64 of the cylindrical member 60 directs the vapor V to the first opening 66 side by imparting directivity to the metal vapor V. Oxygen remaining in the internal space 68 of the cylindrical member 60 is ejected to the outside of the cylindrical member 60, so that the oxygen concentration in the internal space 68 of the cylindrical member 60 is reduced and is inactive around the welded portion 230. Create an atmosphere.

  With reference to FIG. 7B, the welded portion 230 irradiated with the laser solidifies in an inert atmosphere without taking in oxygen. For this reason, it can prevent that an oxide film generate | occur | produces on the weld bead 240. FIG.

  Air a in the atmosphere gradually flows into the internal space 68 of the tubular member 60 in a state in which the pressure is reduced. Since the weld bead 240 is in a state of being cooled and removed from the temperature range in which oxygen is taken in, an oxide film is not generated by oxygen contained in the inflowing air a.

  By using the cylindrical member 60, it can prevent that an oxide film generate | occur | produces on the weld bead 240, and can prevent that the adhesiveness of the coating film formed on the weld bead 240 falls. It becomes possible to prevent the deterioration of the quality of the welded member 200 which may occur with the decrease in the adhesion of the coating film.

  Here, as a conventional technique, in order to prevent an oxide film from being generated on the weld bead, a laser welding apparatus that performs welding if a gas for shielding is blown into the welded part is known. When laser welding is performed using such a conventional laser welding apparatus, there is a problem that the material cost increases with the use of the shielding gas, and the cost for welding work increases. In addition, since a structure for supplying and discharging the shielding gas is added to the laser welding apparatus, the apparatus configuration becomes complicated, resulting in an increase in the manufacturing cost of the apparatus.

  On the other hand, in this embodiment, a laser beam is irradiated in a state where the tubular member 60 is disposed, and an inert atmosphere around the welded portion 230 using the vapor V generated along with the laser irradiation. As a result, the formation of an oxide film on the weld bead 240 is prevented. It is possible to prevent the generation of an oxide film without using a shielding gas, and to prevent an increase in material cost caused by the use of the shielding gas. Furthermore, since laser welding can be performed by the laser welding apparatus 100 having a simple structure to which the cylindrical member 60 is added and the generation of an oxide film can be prevented, the apparatus configuration can be prevented from becoming complicated, and the apparatus configuration can be reduced. It is possible to prevent an increase in the manufacturing cost of the device that may occur with complication.

  As described above, according to the present embodiment, the welded portion 230 covered with the side wall portion 64 of the cylindrical member 60 is irradiated with laser, and the vapor V generated along with the laser irradiation is emitted to the cylindrical member 60. By injecting to the outside, an inert atmosphere can be formed around the welded portion 230. For this reason, it can prevent that an oxide film generate | occur | produces on the weld bead 240, and can prevent the deterioration of the quality of the welding member 200 which may arise with generation | occurrence | production of an oxide film. The generation of an oxide film can be prevented without using a shielding gas, and the cost required to prevent the generation of an oxide film can be reduced. Furthermore, since the generation of an oxide film can be prevented by the laser welding apparatus 100 having a simple structure to which the cylindrical member 60 is added, it is possible to prevent an increase in the manufacturing cost of the apparatus that may occur due to complication of the apparatus configuration.

  Since the side wall portion 64 is formed in a shape extending along the laser irradiation direction, the laser can be irradiated without causing interference to the cylindrical member 60.

  By placing the tubular member 60 against the welding member 200, the tubular member 60 can be placed and the welding member 200 can be clamped at the same time, and the work efficiency of the placement work of the tubular member 60 can be improved. it can. Compared to the case where the clamp device is provided separately, the manufacturing cost of the device can be reduced.

  This embodiment can be changed as appropriate.

  Although the tubular member 60 is pressed against the welding member 200 and disposed, the tubular member 60 is disposed such that no gap is formed between the grounding surface of the second opening 67 and the welding member 200. The arrangement method is not particularly limited.

  The shape of the side wall portion 64 can be appropriately changed in accordance with the incident angle and irradiation direction of the laser, and is not limited to the illustrated shape.

(Modification 1)
Referring to FIG. 8, the laser welding apparatus 100 according to this modification includes a plurality of cylindrical members 61 and 62 that are respectively arranged with respect to the welded portions 231 and 232 at a plurality of locations set in the welding member 200. Have. Description of parts and welding methods similar to those of the above-described embodiment is partially omitted.

  Referring to FIG. 8, when the first and second welded portions 231 and 232 are set on the welding member 200, the first and the second welded portions 231 and 232 are arranged with respect to the first and second welded portions 231 and 232, respectively. The second cylindrical members 61 and 62 are provided in the laser welding apparatus 100.

  At the time of laser welding, laser irradiation is performed with the first and second cylindrical members 61 and 62 disposed. The laser is irradiated in order from the first welded portion 231 to the second welded portion 232.

  Since the second tubular member 62 is disposed in advance in the second welded portion 232, the first tubular member is applied to the second welded portion 232 after irradiating the first welded portion 231 with laser. There is no need to move and arrange 61. For this reason, it is possible to perform laser irradiation on the second welded portion 232 subsequent to laser irradiation on the first welded portion 231.

  When the cylindrical members 61 and 62 are used for laser welding that irradiates a plurality of welds 231 and 232 with laser, the work efficiency of the welding work can be improved.

  As described above, according to the present modification, the laser welding apparatus 100 is provided with a plurality of cylindrical members 61 and 62 that are respectively arranged with respect to the welding portions 231 and 232 at a plurality of locations set on the welding member 200. ing. For this reason, when the cylindrical members 61 and 62 are utilized for the laser welding which irradiates a laser with respect to the some welding parts 231,232, the work efficiency of welding work can be improved.

  In this modification, by attaching the arm part 69 to the first and second tubular members 61 and 62, a function of clamping the welding member 200 to the respective tubular members 61 and 62 is added. However, it is also possible to clamp the welding member 200 using a clamping device separate from the cylindrical members 61 and 62.

  The number of welds and the number of cylindrical members can be changed as appropriate. In addition, the cylindrical member can be formed in a shape extending along the laser irradiation direction in accordance with the laser irradiation angle to form the side wall portion.

(Modification 2)
Referring to FIGS. 9A and 9B, in laser welding apparatus 100 according to the present modification, cylindrical member 60 is provided integrally with clamping means 70 that clamps welding member 200. The tubular member 60 is disposed so as to cover the periphery of the welded portion 230 by the clamping means 70 clamping the welding member 200. A part of the description of the members and welding methods similar to those in the above-described embodiment and modification examples will be omitted.

  With reference to FIG. 9 (A), the welding member 200 in which the welding parts 231 to 233 are set at a plurality of positions as shown in the figure is clamped by the clamping means 70. At this time, when the cylindrical members 61 to 63 provided separately from the clamping unit 70 are arranged, the clamping member 70 clamps the welding member 200 and the cylindrical members 61 to 63 are arranged on the welding member 200. Work is required, and there is a risk of work delay due to the use of the cylindrical members 61-63.

  With reference to FIG. 9 (B), the cylindrical members 61 to 63 are provided integrally with the clamping means 70, and the clamping member 70 clamps the welding member 200, whereby the clamping operation by the clamping means 70 and the cylindrical member are performed. 61 to 63 can be arranged simultaneously. For this reason, when using the cylindrical members 61-63 with the clamp means 70, it becomes possible to reduce the work delay which may arise by using the cylindrical members 61-63.

  In the embodiment and the modification described above, the welding member 200 is clamped only by the tubular member 60. However, in the present modification, the clamping means 70 and the tubular members 61-61 are configured. Since the welding member 200 can be clamped by 63, the welding member 200 can be clamped more firmly.

  As described above, according to this modification, since the cylindrical members 61 to 63 are provided integrally with the clamp means 70 for clamping the welding member 200, the clamping operation of the welding member 200 by the clamping means 70 and the cylinder The arrangement work of the member 60 can be performed simultaneously. For this reason, when using the cylindrical members 61-63 with the clamp means 70, the work delay which may arise by using the cylindrical members 61-63 can be reduced.

  The number of welds and the number of cylindrical members can be changed as appropriate.

  The present invention can be modified as appropriate.

  The outer shape of the cylindrical member 60 is not limited to the illustrated cylindrical shape. As long as it has a volume that can be filled with steam generated in the tubular member, and can be formed from the internal space of the tubular member to the outside, an inert atmosphere can be formed around the welded portion, and the appropriate change is made. Is possible.

  The arrangement, shape, and material of the welding member can be changed as appropriate.

  The laser welding apparatus and laser welding method of the present invention can be widely applied to laser welding for the purpose of suitably preventing an oxide film from being generated on a weld bead formed by laser welding.

  Embodiments of the present invention will be specifically described below based on examples. In addition, this invention is not limited only to these Examples, It can change suitably.

Example 1
Referring to FIGS. 10A and 10B, in Example 1, the relationship between the height dimension h and the inner diameter dimension d1 of the cylindrical member 60 capable of preventing the generation of an oxide film. Was examined.

  Laser welding was performed by changing the height dimension h and the inner diameter dimension d1 of the cylindrical tubular member 60, and the influence of the shape of the tubular member 60 on the presence or absence of the occurrence of an oxide film was examined from the results.

  The laser welding apparatus 100 was previously taught the laser output, the laser scanning speed, and the welding locus. As the welding member 200, steel plates having a thickness of 1.4 mm and 0.65 mm arranged in an overlapping manner were used. Specifically, the laser was irradiated under the following conditions.

(1) Laser output input to the laser oscillator: 4000 W
(2) Scanning speed of irradiated laser: 70 mm / s
(3) The laser is scanned along a circular welding trajectory so that the diameter d2 of the weld bead is 5 mm (the diameter d2 of the weld bead is a distance between the weld bead center positions).

  Referring to FIG. 11, a condition where it is determined that no oxide film is formed on weld bead 240 is marked with a mark. The conditions for determining that the oxide film generated on the weld bead 240 has a thickness dimension (0.5 to 2.0 μm) that does not affect the adhesion of the coating film are marked with Δ. ing. Conditions marked as having an oxide film formed with a thickness dimension (2 μm or more) that adversely affects the adhesion of the coating film are marked with x.

  From this result, it can be seen that when the inner diameter dimension d1 of the tubular member 60 is the same, the larger the height dimension h of the tubular member 60 can suppress the generation of the oxide film more effectively. When the height dimension h of the cylindrical member 60 is low, the air a in the atmosphere easily flows around the welded portion 230, so that it is difficult to form an inert atmosphere.

(Example 2)
Referring to FIG. 12, in Example 2, a plurality of types of weld beads 240 having different areas S (areas indicated by broken lines in FIG. 10B) are formed. The relationship with the shape of the cylindrical member 60 capable of preventing the generation of a film was examined. The figure shows the relationship between the height dimension h and the inner diameter dimension d1 of the cylindrical member 60 from which the determination result that no oxide film was formed was obtained for each weld bead 240 formed with a different area. ing.

The weld bead 240 having the condition indicated by the straight line is formed in an area having a size of 12 mm ² . The weld bead 240 under the condition indicated by the broken line is formed in an area having a size of 20 mm ² . The weld bead 240 having the condition indicated by the alternate long and short dash line is formed in an area having a size of 33 mm ² . Other conditions related to laser welding were performed under the same conditions as in Example 1 described above.

  From this result, when the area S of the weld bead 240 increases, the amount of oxygen consumed when the welding member 200 evaporates increases. Therefore, in the cylindrical member 60 having the same inner diameter dimension d1, the height dimension h It can be confirmed that a smaller value can be set.

10 Laser welding robot,
20 laser processing head,
21 lens group,
22 Optical mirror,
30 robot arm,
35 optical fiber,
40 control unit,
50 laser oscillator,
60 tubular member,
64 side wall,
65 opening,
66 first opening,
67 second opening,
68 the internal space of the tubular member,
69 arm part,
70 clamping means,
80 mounting table,
100 laser welding equipment,
200 welded parts,
210 a first welding member;
220 second welding member,
230 welds,
240 weld beads,
V steam,
a Air.

Claims (6)

  A side wall portion that covers the periphery of the welded portion of the welding member and an opening that passes through the side wall portion and allows the laser irradiated to the welded portion to pass through are formed from the welded portion during welding. Welding apparatus having a cylindrical member having a volume capable of being filled with steam.   The laser welding apparatus according to claim 1, wherein the side wall portion is formed so as to extend along a laser irradiation direction with respect to the welding portion.   3. The laser welding apparatus according to claim 1, wherein the cylindrical member clamps the welding member by being pressed against the welding member. 4.   The said cylindrical member is integrally provided in the clamp means which clamps the said welding member, The said clamp means is arrange | positioned covering the circumference | surroundings of the said welding part by clamping the said welding member. The laser welding apparatus according to any one of the above.   The laser welding apparatus according to any one of claims 1 to 4, further comprising a plurality of the cylindrical members that are respectively arranged with respect to the welding portions at a plurality of locations set in the welding member.   A laser welding method in which the periphery of a welded portion of a welded member is covered with a container and laser is irradiated to the welded portion.

Images