JP2003112525A - Manufacturing method of automobile door frame - Google Patents

Abstract

The size of a weld bead M formed by melting and feeding a filler wire at a location higher than a butt portion to be welded by laser RA welding of two members. Small and less distorted by heat. Therefore, it is an object to reduce the amount of surface matching in finishing the butt portion and greatly reduce the finishing man-hours. In a manufacturing method of an automobile door frame in which a butted portion between a first door frame member 1a and a second door frame member 1b is laser-welded with a filler wire 3, the focus of the laser RA is applied to the butting portion S. The filler wire tip 3a is disposed in the laser irradiation spaced inward from the focal point of the laser, and the butt portion and the filler wire are melted by the laser, whereby the first door frame member And the second door frame member are welded to each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an automobile door frame.

[0002]

2. Description of the Related Art FIG. 5 is a schematic front view of a general automobile door as seen from outside the automobile. The vehicle door frame 30 is a frame that supports a door glass 32, and includes a door panel 31.
It is provided by connecting to. The door frame 30 for an automobile is formed in a frame shape by joining a main frame 30a having a curved shape or a corner portion and a substantially linear center pillar 30b. The abutting portion 33 is often provided in a portion that becomes the corner portion 30c of the vehicle door frame.

FIG. 7 is a sectional view of a general automobile door frame. The upper part of FIG. 7 is a design surface 34 facing the outside of the automobile. The concave portion on the left side of FIG. 7 is a glass holding portion 35 that holds the door glass through the mohair, and the concave portion on the right side is a weather strip holding portion 36 that holds a weather strip that prevents entry of rain into the vehicle. . Figure 7
The lower annular portion is a rigidity securing portion 37 for securing the rigidity of the door frame. This cross section is generally formed by processing a steel sheet by roll forming.

Since the cross section of the vehicle door frame has a complicated shape as described above, conventionally, the corner portion 30c is welded by the design surface 34 side of the abutting portion 33 and the rigidity securing portion 3.
7 was joined by TIG or MIG welding.

[0005]

Problems to be Solved by the Invention TIG welding or MI
In G welding, a welding bead is formed by a droplet formed by a base material and a welding rod (in the case of MIG, an electrode wire replaces the welding rod) by an arc from a gas nozzle. However, due to the structure of the size of the gas nozzle, welding is performed with a wider radius than the desired welding site, so the welding bead becomes larger than the required welding site (about 5 mm in width and height of welding bead). About 1m
m). Moreover, since the amount of heat input becomes large, the butt surface due to heat is distorted.

On the design surface 34, which is required to be beautiful in appearance, a finishing process is required with a sander or the like in order to ensure appearance quality. Therefore, it is necessary to scrape the weld bead and finish it while maintaining the smoothness with the non-welded portion. Since the weld bead made of this metal is difficult to scrape, and it is also difficult to scrape only the weld bead, there is a problem in that a part that does not need to be scraped is scraped off, resulting in defective finishing.

Further, since deformation due to heat also occurs, a step of correcting the deformation is required, which causes a problem of high cost. Thus, finishing the door in particular requires skilled skills.

Other welding methods include electron beam welding and laser welding. However, as long as butt welding is used, a cutting product used for a precision component of two members is targeted.

The reason for this is that in the case of highly accurate cut products, the deviation of the laser focus portion from the abutting portion is small (1/100).
Since it is on the order of 0 mm), electron beam welding and laser welding were used because the focal area narrowed down by the condenser lens is small and welding efficiency is good.

On the other hand, in the butt parts of products such as extrusion process and forging process by plastic working or roll forming, the precision of the product is low (on the order of 1/100 mm unit), so electron beam welding with a narrow laser focus area is performed. , It could not be applied to laser welding.

The present invention has solved the above-mentioned problems. A welding bead formed by melting and feeding a filler wire at a position higher than a butt portion to be welded by laser welding of two members and feeding the filler wire. The size is small and the distortion due to heat is small. Therefore, the amount of face-to-face matching at the butting portion is reduced, the number of finishing steps can be greatly reduced, and a low-cost method for manufacturing an automobile door frame is provided.

[0012]

The invention according to claim 1 made in order to solve the above technical problem is an automobile in which a butt portion of a first door frame member and a second door frame member is laser-welded with a filler wire. In the method for manufacturing a door frame for a vehicle, the focus of the laser is irradiated to the abutting portion, the tip of the filler wire is disposed in the laser irradiation spaced inward from the focus of the laser, and the abutting portion is formed by the laser. And the first door frame member and the second door frame member are welded by melting the filler wire.

According to the first aspect of the present invention, the filler wire is melted and fed at a position higher than the butt portion to be welded by laser welding of the two members, and the welding is performed while feeding the filler wire. The tolerance for the gap is increased, and laser welding can be performed.

Further, in the case of laser welding, since the energy density is high, a part of the two members as the base material can be melted, and the volume of the melted portion is very small as compared with TIG welding and MIG welding. Therefore, it is possible to form a weld bead in which the amount of the filler wire to be put in the fusion zone (or coated on the upper surface) is small.

Further, since the size of the weld bead to be formed is small and the distortion due to heat is small, the amount of face-to-face matching at the finish of the butted portion is small, and the number of finishing steps can be greatly reduced. Further, if the weld bead is small, it is possible to complete no finishing in the case of a vehicle having a resin or metal garnish mounted on the outside of the center pillar. Further, if the weld bead of the abutting portion in the rigidity ensuring portion arranged on the back surface of the door frame becomes small, it is possible to eliminate the need for sanding the weld bead to prevent interference with other members.

In order to solve the above technical problem, the invention of claim 2 is characterized in that the distance between the focus of the laser and the tip of the filler wire is 0.2 to 0.8 mm. Item 2. A method for manufacturing an automobile door frame according to Item 1.

The invention according to claim 2 is a configuration in which the technical means according to claim 1 is more embodied, and has the effect of claim 1 when it is within the above numerical range.

If it is less than 0.2 mm, the gaps and steps in the abutting portions of the two members cannot be absorbed by laser welding. When it is larger than 0.8 mm, the energy density of the laser is small and the filler wire is not melted so that the weld bead is not formed.

In order to solve the above technical problems, the invention of claim 3 is that the first door frame member and the second door frame member are members processed by plastic working, extrusion processing or forging processing. A method for manufacturing an automobile door frame characterized by the above.

According to the third aspect of the present invention, laser welding can be performed even for a product having a variation in product shape such as plastic working that is not a precise product such as cutting, extrusion by roll forming or forging.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.
It will be described with reference to the drawings. FIG. 1 is a front view of the vehicle door frame of the first embodiment as seen from the outside of the vehicle. When the corner portions of the first door frame member (front door frame 1a, rear door frame 1c) and the second door frame member (second door frame member 1b, rear pillar 1d) are butted, a matching streak is formed. The alignment stripe is the butt portion 2 that serves as a welded portion. FIG. 2 is an enlarged view of the abutting portion S of the corner portion of the two members, and the abutting portion S is laser-welded. FIG. 3 is a sectional view taken along the line AA of FIG.

The door frame members 1a and 1b are members applied to members formed by plastic working by extrusion. Figure 2
In, the cut end surface of the first door frame member 1a and the cut end surface of the second door frame member 1b are butted against each other. The abutting portion S is provided between the end surface of the first door frame member 1a and the end surface of the second door frame member 1b.
There is a gap in.

FIG. 4 shows an outline of a laser welding apparatus for carrying out the present invention. First door frame member 1a
An emission optical device 12 having a condenser lens 11 is positioned immediately above the abutting portion between the second door frame member 1b and the second door frame member 1b. The laser RA output from the laser oscillator R is converged by the condenser lens 11 and its focus is adjusted so as to come to the abutting portion S.

At the time of welding, the filler wire 3 is automatically fed to the butting portion S between the first door frame member 1a and the second door frame member 1b. The emitting optical device 12 having the condenser lens 11 and the wire feeding nozzle 16 for feeding the filler wire 3 are configured to move integrally in the welding direction. The filler wire 3 is
It is fed from the wire feeding nozzle 16 to the abutting portion S via a wire feeding tube (not shown) attached along the emission optical device 12. A nozzle for emitting the laser RA is arranged at the tip of the emission optical device 12.

The focus of the laser RA is the upper end S of the abutting portion S.
The tip 3a of the filler wire 3 is irradiated with the laser R
It is arranged in the laser irradiation away from the focal point of A,
The first door frame member 1a and the second door frame member 1b are welded by melting the butt portion S and the filler wire 3 by the laser RA, and then manufacturing the automobile frame of the present invention by laser welding. A specific operation example of the method will be described. As shown in FIG. 4, when the first door frame member 1a and the second door frame member 1b are set at predetermined positions, the laser oscillator R outputs the laser RA, and the laser RA is the condenser lens 11
The upper end portion SA of the abutting portion S with the first door frame member 1a and the second door frame member 1b is irradiated through.

At the same time, the tip of the filler wire 3 is arranged in the laser irradiation spaced inwardly from the focus of the laser RA, and the filler wire is applied to the irradiation portion above the upper end SA of the abutting portion S of the laser RA. 3 is automatically fed.

As shown in FIG. 5, when the irradiation of the laser RA is started, the abutting portions of the first door frame member 1a and the second door frame member 1b are heated and melted to form a weld bead. This weld bead M is the first weld bead M
1 is formed, and the second welding bead M2 is formed by heating and melting the filler wire 3. Further, the third weld bead M3 is formed by mixing between the first weld bead M1 and the second weld bead M2.

The boundary surface of the abutting portion S has a first weld bead M1.
And the third weld bead M3 mixed with the second weld bead M2 to be in an alloy state is formed.

As described above, in order to increase the tolerance for variations (steps and gaps) in the abutting portions S of the two members, the filler wire 3 is made to be two as in the conventional laser welding.
Instead of directly inserting it into the molten pool of the members, a position (laser R
The distance L between the focus of A and the tip of the filler wire is 0.
2 to 0.8 mm) so that the filler wire 3 is melted and coated on the abutting portion S of the two members.

When welding is carried out by the above manufacturing method, the filler wire is melted and fed at a position higher than the butt portion to be welded by laser welding of two members, and welding is carried out,
The tolerance for variations (steps, gaps) in the abutting portions of the two members is large, and laser welding is also possible.

Further, in the case of laser welding, since the energy density is high, a part of the two members as the base material can be melted, and the volume of the melted portion is very small as compared with TIG welding and MIG welding. Therefore, it is possible to form a weld bead in which the amount of the filler wire to be put in the fusion zone (or coated on the upper surface) is small.

Further, since the size of the weld bead to be formed is small and the distortion due to heat is small, the amount of face-to-face matching at the finish of the butted portion is small, and the number of finishing steps can be greatly reduced. Further, if the weld bead is small, it is possible to complete no finishing in the case of a vehicle having a resin or metal garnish mounted on the outside of the center pillar. Further, if the weld bead of the abutting portion in the rigidity ensuring portion arranged on the back surface of the door frame becomes small, it is possible to eliminate the need for sanding the weld bead to prevent interference with other members.

Further, in the conventional method of manufacturing an automobile door frame by Tig welding or Mig welding, a clamp jig for fixing two members can be brought close to the butt welding portion due to interference of the torch of welding or the like. I didn't,
In the laser welding manufacturing method of the present invention, since the distance from the lens of the laser RA to the focal point (focusing point) is relatively long, there is no interference. Therefore, since the clamp jig for fixing the two members can be brought close to the butt welding portion, the load of the clamp retainer is increased, and the butt accuracy is improved.
It is possible to suppress variations in members.

[0034]

As described above, according to the present invention, in the method for manufacturing an automobile door frame in which the abutting portion of the first door frame member and the second door frame member is laser-welded with a filler wire, the focus of the laser is provided. Is irradiated to the abutting portion, the filler wire tip is disposed in the laser irradiation spaced inward from the focus of the laser,
Since the first door frame member and the second door frame member are welded by melting the butt portion and the filler wire by the laser, it is a method for manufacturing an automobile door frame. By welding the filler wire by melting and feeding the filler wire at a position higher than the butt portion to be welded by laser welding of the two members, variations in the butt portion of the two members (steps, gaps)
Tolerance is increased, and laser welding can be performed.

Further, in the case of laser welding, since the energy density is large, it is possible to melt a part of the two members which are the base materials, and the volume of the molten portion is very small compared to TIG welding and MIG welding. Therefore, it is possible to form a weld bead in which the amount of the filler wire to be put in the fusion zone (or coated on the upper surface) is small.

Further, since the size of the weld bead to be formed is small and the distortion due to heat is small, the amount of face-to-face matching at the finish of the butt portion is small, and the number of finishing steps can be greatly reduced. Further, if the weld bead is small, it is possible to complete no finishing in the case of a vehicle having a resin or metal garnish mounted on the outside of the center pillar. Further, if the weld bead of the abutting portion in the rigidity ensuring portion arranged on the back surface of the door frame becomes small, it is possible to eliminate the need for sanding the weld bead to prevent interference with other members.

[Brief description of drawings]

FIG. 1 is a front view of an automobile door frame according to the present invention as seen from outside the vehicle.

FIG. 2 is an enlarged front view of the automobile door frame butt portion of the present invention after welding.

3 is a sectional view taken along the line AA of FIG.

FIG. 4 is a schematic view of a laser welding apparatus of the present invention.

FIG. 5 is an enlarged cross-sectional view of a molten bead at a butt portion of two members.

FIG. 6 is a front view of a general vehicle door frame.

FIG. 7 is a cross-sectional view of a general automobile door frame.

[Explanation of symbols]

1a ... 1st door frame member (front door frame) 1b ... 2nd door frame member (center pillar) 1c ... 1st door frame member (rear door frame) 1d ... 2nd door frame member ( Rear pillar) 3 ... Filler wire 3a ... Filler wire tip portion M ... Weld bead S ... Butt portion SA ... Butt portion upper end portion

Claims (3)

[Claims] 1. A method of manufacturing a door frame for an automobile, wherein a butt portion of a first door frame member and a second door frame member is laser-welded with a filler wire, wherein a focal point of the laser is applied to the butt portion, and the filler is applied. The wire tip is disposed in the laser irradiation spaced inward from the focus of the laser, and the laser melts the abutting portion and the filler wire, whereby the first door frame member and the second door A method for manufacturing an automobile door frame, which comprises welding with a frame member. 2. The method of manufacturing an automobile door frame according to claim 1, wherein a distance between the focus of the laser and the tip of the filler wire is 0.2 to 0.8 mm. 3. The method of manufacturing an automobile door frame, wherein the first door frame member and the second door frame member are members processed by plastic working, extrusion working, or forging working.