JP5192410B2 - Laser welding method - Google Patents

Description

  The present invention relates to a laser welding method for welding a flange portion of a rafter member to a roof plate constituting a roof structure of a railway vehicle.

  As a conventional technique related to this type of field, for example, there is a railway vehicle described in Patent Document 1. In this railway vehicle, a rib having a T-shaped cross section is formed on the inner side surface of the roof plate along the longitudinal direction of the vehicle, and a rafter member is welded to the flange portion of the rib. In recent years, laser welding has attracted attention as a welding method for members of a railway vehicle structure. Laser welding has the advantage that the amount of heat input to the member can be suppressed compared to conventional MIG welding and the like, and a railway vehicle structure with less distortion can be formed.

Japanese Patent No. 2734328

  By the way, the roof structure of a railway vehicle often has a curved shape that is convex upward. So, in patent document 1 mentioned above, a roofing board is supported by the mounting jig which has a curved surface which corresponds to the shape of a roofing board, the rafter member is installed in the surface, and both are welded (patent literature) 1 (see FIG. 1). However, in this welding method, a mounting jig having a complicated shape must be prepared in accordance with the curved shape of the roof plate, and there is a problem in terms of manufacturing cost.

  On the other hand, as a method that does not use a mounting jig, a method in which rafter members are arranged in advance at a predetermined arrangement pitch and a roof plate is placed on the frame of the rafter member is conceivable. In this case, although a mounting jig having a complicated shape is not required, there arises a problem that it is difficult to visually recognize the arrangement position of the rafter members by being shielded by the roof plate. Therefore, when laser welding is applied to the welding between the roof plate and the rafter member, depending on the accuracy of the arrangement pitch of the rafter members and the accuracy of the laser beam irradiation pitch, the irradiation position of the laser beam is different between the roof plate and the rafter member. There is a risk that the welding yield will be lowered due to deviation from the planned welding position at the contact portion.

  The present invention has been made in order to solve the above-mentioned problems, and a laser joining method capable of welding a roof plate and a rafter member with a good yield without using a mounting jig having a complicated shape. The purpose is to provide.

  In order to solve the above problems, a laser welding method according to the present invention is a laser welding method for welding a flange portion of a rafter member to a roof plate constituting a roof structure of a railway vehicle, wherein the rafter members are arranged at a predetermined arrangement pitch. A rafter arrangement process arranged in parallel and a roof in which the roof plate is placed on the rafter member so that the rafter member extends in the width direction of the railway vehicle, and the flange portion of the rafter member and the bottom surface of the roof plate are brought into contact with each other A plate mounting step and a laser beam irradiation step of irradiating a laser beam along the arrangement direction of the rafter members from the upper surface side of the roof plate. In the laser beam irradiation step, the irradiation pitch of the laser beams is arranged in the arrangement of the rafter members. The width is equal to the pitch, and the irradiation width of the laser beam is made larger than the contact width between the bottom surface of the roof plate and the flange portion of the rafter member.

  In the laser welding method according to the present invention, a rafter member is arranged in advance at a predetermined arrangement pitch to form a frame body with the rafter member, and a roof plate is placed on the frame body. Thereby, even if it is a case where a roof board has a curved shape, the flange part of a rafter member can be contact | abutted with respect to a roof board, without using the mounting jig of a complicated shape. On the other hand, in the arrangement configuration of the roof board and the rafter member, it is difficult to visually recognize the arrangement position of the rafter member because it is shielded by the roof board in the laser beam irradiation process. However, in the laser welding method according to the present invention, the laser beam irradiation pitch is matched with the arrangement pitch of the rafter members, and the laser beam irradiation width is set to the contact width between the bottom surface of the roof plate and the flange portion of the rafter member. Is bigger than. As a result, even if the arrangement pitch of the rafter members and the irradiation pitch of the laser beam are slightly shifted, it is possible to prevent the laser beam irradiation position from being detached from the contact portion between the bottom surface of the roof plate and the flange portion of the rafter member. The flange portion of the rafter member can be welded to the roof plate with a good yield.

  In the laser welding method according to the present invention, the roof plate and the rafter member can be welded with a good yield without using a mounting jig having a complicated shape.

It is a perspective view which shows a railroad vehicle structure provided with the roof structure manufactured using one Embodiment of the laser welding method which concerns on this invention. It is a perspective view which shows the detailed structure of the roof structure shown in FIG. It is a figure which shows the procedure of the laser welding of a roof board and a rafter member. It is a figure which shows the procedure of the subsequent process of FIG. It is a figure which shows the procedure of the subsequent process of FIG.

  Hereinafter, preferred embodiments of a laser welding method according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing a railway vehicle structure including a roof structure manufactured using an embodiment of a laser welding method according to the present invention. As shown in the figure, the railway vehicle structure 10 has a substantially box-like shape having a space for accommodating passengers therein, and is located on the frame 12 located at the bottom of the vehicle and on both sides of the vehicle. A side structure 14 having a plurality of vehicle windows, a wife structure 16 positioned in front of and behind the vehicle, and a roof structure 18 positioned in the upper part of the vehicle.

  Specifically, the underframe 12 has a substantially rectangular shape and is disposed at the bottom of the vehicle structure 10. On the periphery of the frame 12, side structures 14 located on both sides and end structures 16 positioned on the front side and the rear side of the vehicle are erected so as to surround the frame 12. The roof structure 18 is curved in an arch shape so as to be convex upward, and is disposed so as to close a space constituted by the side structure 14 and the wife structure 16.

  Next, the roof structure 18 will be described in detail. FIG. 2 is a perspective view showing a detailed structure of the roof structure 18 shown in FIG. The roof structure 18 includes a roof plate 22 and a plurality of rafter members 26.

  The roof plate 22 is formed using stainless steel such as SUS301L defined by JIS, for example. The thickness of the roof plate 22 is, for example, 0.6 mm to 0.8 mm, the length is 7500 mm, and the width is 2.7 m to 2.85 m. The curvature radius of the roof plate 22 is, for example, 1500 mm at both ends in the width direction of the roof plate 22, and is, for example, 5000 mm at the center, and as a whole, is curved in an arch shape so as to protrude upward.

  A plurality of protrusions 24 extending in the longitudinal direction of the roof plate 22 are formed on the upper surface 22 a of the roof plate 22. The protrusion 24 is formed integrally with the flat plate portion by, for example, roll forming. The protrusions 24 are arranged in parallel with each other, and the arrangement pitch of the protrusions 24 is, for example, 100 mm to 150 mm. Moreover, the height of the protrusion part 24 is 10 mm-15 mm, for example. These protrusions 24 function as reinforcing materials that secure the strength of the roof plate 22.

  The rafter member 26 is made of stainless steel such as SUS301L defined by JIS, for example. The rafter member 26 includes a flange portion 26a, a web portion 26b that hangs at right angles from an end in the width direction of the flange portion 26a, and a flange portion 26c that protrudes from the lower end portion of the web portion 26b to the opposite side of the flange portion 26a. In addition, it has a long shape with a substantially Z-shaped cross section. The rafter member 26 is curved in an arch shape so as to be convex upward so as to match the shape of the roof plate 22. The width of the flange portions 26a and 26c is, for example, 30 mm. Moreover, the height of the web part 26b is 40 mm, for example, and the thickness is 1.0 mm-1.5 mm, for example.

  The rafter members 26 are arranged in parallel with an arrangement pitch P <b> 1 so as to extend in the width direction of the roof plate 22, and form a frame body 27 on the bottom surface 22 b side of the roof plate 22. The arrangement pitch P1 of the rafter members 26 is defined by, for example, an interval from the position of the front end of the flange portion 26a in one rafter member 26 to the position of the front end of the flange portion 26a in the adjacent rafter member 26, for example, 300 mm to 500 mm. It has become. In addition, the interval from the end 22c in the longitudinal direction of the roof plate 22 to the position of the tip of the flange 26a in the rafter member 26 closest to the end 22c also conforms to the arrangement pitch P1.

  The roof plate 22 and the rafter member 26 are welded in a state in which the upper surface of the flange portion 26a of each rafter member 26 is in contact with the bottom surface 22b of the roof plate 22 with a contact width W1 that matches the width of the flange portion 26a. The portion 28 is firmly joined. The welded portion 28 is formed by, for example, laser welding, and is a so-called non-penetrating welded portion that extends from the upper surface 22a of the roof plate 22 to approximately half the depth of the flange portion 26a of the rafter member 26, for example.

  As shown in FIG. 2, the welded portion 28 that joins the roof plate 22 and the rafter member 26 is formed on the welding lines L <b> 1 and L <b> 2 formed between the adjacent projections 24 and 24 of the roof plate 22. Has been. The welded portions 28 are arranged with an arrangement pitch P2 in the arrangement direction of the rafter members 26 on the respective welding lines L1 and L2. The arrangement pitch P2 is defined by an interval from the start point of one welded portion 28 to the start point of the adjacent welded portion 28, and is, for example, 300 mm to 500 mm so as to coincide with the arrangement pitch P1 of the rafter member 26. Further, when viewed from the upper surface 22a side of the roof plate 22, the width W2 from the start point to the end point of the welded portion 28 is, for example, 40 mm, and the contact width W1 between the bottom surface 22b of the roof plate 22 and the flange portion 26a It is approximately 10 mm larger than the contact width W <b> 1 in a state where the centers substantially coincide.

  Next, the laser welding method according to this embodiment will be described. FIG. 3 is a diagram showing a procedure of laser welding of the roof plate 22 and the rafter member 26, FIG. 4 is a diagram showing a procedure of a subsequent process of FIG. 3, and FIG. It is a figure which shows the procedure of a process. The laser welding method according to the present embodiment includes a rafter arrangement process, a roof plate placing process, and a laser beam irradiation process.

  In the rafter arrangement step, a plurality of rafter members 26 are prepared as shown in FIG. Then, the rafter members 26 are arranged in parallel at the arrangement pitch P <b> 1 to form a frame 27 of the rafter member 26. In the next roof plate placement step, for example, a roof plate 22 having projections 24 formed by roll forming is prepared. Then, the roof plate 22 is placed on the frame 27 so that the rafter member 26 extends in the width direction of the vehicle structure 10, and the bottom surface 22b of the roof plate 22 and the upper surface of the flange portion 26a are brought into contact with each other. When the roof plate 22 is placed, the interval from the end portion 22c in the longitudinal direction of the roof plate 22 to the position of the tip of the flange portion 26a in the rafter member 26 closest to the end portion 22c is made to conform to the arrangement pitch P1. .

  In the laser beam irradiation step, first, a processing head 32 that emits a laser beam is disposed above the end portion 22 c of the roof plate 22. Next, as shown in FIG. 4A, the machining head 32 is scanned along the arrangement direction of the rafter members 26, and the laser beam 34 is irradiated from a position before the tip of the flange portion 26 a in the first rafter member 26. To start. Then, the irradiation of the laser beam 34 is stopped when the irradiation width from the point where the irradiation of the laser beam 34 is started reaches W2. Thereby, as shown in FIG.4 (b), the welding part 28 of the width W2 which corresponds to the irradiation width W2 is formed in the irradiation part of the laser beam 34. As shown in FIG.

  Next, as shown in FIG. 5A, with the laser beam 34 turned off, the irradiation pitch P2 is such that the distance from the starting point of the weld 28 formed first matches the arrangement pitch P1 of the rafter members 26. The machining head 32 is scanned to a position, and irradiation of the laser beam 34 is started from a position before the tip of the flange portion 26a in the second rafter member 26. Thereafter, by repeating the same procedure, the roof plate 22 and each rafter member 26 are firmly fixed by the welded portion 28 on the welding line L1, as shown in FIG.

  Thereafter, with respect to the welding line L2, the roof plate 22 and the rafter members 26 are welded in the same procedure, and the welding lines L1 and L2 are formed between the protrusions 24 and 24, as shown in FIGS. A roof structure 18 is obtained.

  Note that the laser output and welding speed in the laser beam irradiation step can be appropriately adjusted according to the thickness of the roof plate 22 and the flange portion 26a. In this embodiment, for example, the laser output and the welding speed are adjusted in advance so that heat is transferred from the upper surface 22a of the roof plate 22 to a depth approximately half of the flange portion 26a, and the laser output is adjusted to 4 kW, for example. The speed is adjusted to 6 m / min, for example.

  As a device for outputting the laser beam 34, a known laser processing device can be used. A filler wire made of the same material as the roof plate 22 and the rafter member 26 may be supplied to the irradiation position of the laser beam 34 as necessary. Further, a shield gas may be supplied to the irradiation position of the laser beam 34 for the purpose of preventing oxidation of the welded portion 28 or the like. For example, argon gas can be used as the shielding gas. In the above-described embodiment, when supplying argon gas, the supply amount is preferably set to, for example, 30 liters / min.

  As described above, in the laser welding method according to the present embodiment, the rafter member 26 is arranged in parallel at a predetermined arrangement pitch P1 in advance to constitute the rafter member 26 frame 27, and on the frame 27 A roof plate 22 is placed. Thereby, even if it is a case where the roofing board 22 has a curved shape toward upper direction like this embodiment, a roofing board is used, without using the mounting jig of a complicated shape according to the shape of the roofing board 22. The flange portion 26a of the rafter member 26 can be brought into contact with the rafter member 22.

  On the other hand, in such an arrangement configuration of the roof plate 22 and the rafter member 26, it is difficult to visually recognize the arrangement position of the rafter member 26 by being shielded by the roof plate 22 in the laser beam irradiation process. However, in the laser welding method according to the present embodiment, the irradiation width P2 of the laser beam 34 is set to be equal to the arrangement pitch P1 of the rafter members 26 and the irradiation width W2 of the laser beam 34 is set to the bottom surface 22b of the roof plate 22 and the flange. The contact width W1 with the portion 26a is made larger. Thereby, even if the arrangement pitch P1 of the rafter members 26 and the irradiation pitch P2 of the laser beam 34 are slightly shifted, the irradiation position of the laser beam 34 is deviated from the contact portion between the bottom surface 22b of the roof plate 22 and the flange portion 26a. Can be prevented. Therefore, the flange portion 26a of the rafter member 26 can be welded to the roof plate 22 with a good yield, although the arrangement configuration in which the rafter member 26 is difficult to be visually recognized by being shielded by the roof plate 22 can be achieved.

  In the laser welding method according to the present embodiment, in the roof plate placing step, the pitch between the longitudinal end portion 22c of the roof plate 22 and the rafter member 26 closest to the end portion 22c is the arrangement pitch P1. The roof plate 22 is placed on the frame 27 so as to comply with the above. In this case, in the laser beam irradiation process, the position of the contact portion between the roof plate 22 and the flange portion 26a can be easily grasped by using the end portion 22c of the roof plate 22 as a reference. Thereby, the welding part 28 can be reliably formed in the contact part of the roof plate 22 and the flange part 26a. Therefore, the welding yield can be further improved.

  Further, in the laser welding method according to the present embodiment, the width W2 of the welded portion 28 is set to substantially coincide with the contact width W1 between the bottom surface 22b of the roof plate 22 and the flange portion 26a. Thereby, the welding part 28 will be formed from the one end part of the width direction of the contact part of the roof board 22 and the flange part 26a to the other end part, and the roof board 22 and the rafter member 26 are joined more firmly. be able to.

  The present invention is not limited to the above embodiment. In the embodiment described above, two welding lines are formed between the adjacent protrusions 24, 24, but one or three or more welding lines may be formed. Moreover, the welding part 28 should just be formed in at least one part of the contact part of the roof board 22 and the flange part 26a. Furthermore, in the embodiment described above, the welded portion 28 is a non-penetrated welded portion, but the welded portion 28 may be a so-called through welded portion exposed on the bottom surface of the flange portion 26a. The rafter member 26 is not limited to a substantially Z-shaped cross section, and members having various cross-sectional shapes can be used.

  DESCRIPTION OF SYMBOLS 10 ... Vehicle structure, 18 ... Roof structure, 22 ... Roof board, 22a ... Upper surface, 22b ... Bottom surface, 26 ... Rafter member, 26a, 26c ... Flange part, 28 ... Welded part, 34 ... Laser beam, P1 ... Arrangement pitch, P2 ... irradiation pitch, W1 ... contact width, W2 ... irradiation width.

Claims (1)

A laser welding method for welding a flange portion of a rafter member to a roof plate constituting a roof structure of a railway vehicle,
A rafter arrangement step of arranging the rafter members in parallel at a predetermined arrangement pitch;
The roof plate is placed on the rafter member so that the rafter member extends in the width direction of the railway vehicle, and the flange portion of the rafter member and the bottom surface of the roof plate are brought into contact with each other. Placing process;
A laser beam irradiation step of irradiating a laser beam along the arrangement direction of the rafter members from the upper surface side of the roof plate,
In the laser beam irradiation step, the laser beam irradiation pitch is made to coincide with the arrangement pitch of the rafter members, and the irradiation width of the laser beam is set between the bottom surface of the roof plate and the flange portion of the rafter member. A laser welding method characterized by being larger than the contact width.

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