JP2009190050A - Joining method of vehicle body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent seal failure of a welding part by preventing dust caused during spot welding from scattering outside a vehicle body in a method of spot-welding metal sheets with an adhesive agent disposed therebetween. <P>SOLUTION: A roof panel 5 set in a positioning jig is located relative to a roof side rail 1. A rising part 5b is formed at the outer edge part outside the vehicle body of the roof panel 5 and a step part 5a is formed at a place corresponding to the adhesive agent 6. As a state before welding, the bottom of the rising part 5b of the roof panel 5 abuts on the flange 2a inside the vehicle body of a cab side outer part 2, and the adhesive agent 6 is stored in a space between the step part 5a closer to the inside of the vehicle body than the rising part 5b and the flange 2a. Electrodes 17, 18 are made to approach with each other at the position of the step part 5a, the step part 5a of the roof panel 5 and the flange 2a of the cab side outer part 2 are pressurized in a state with the adhesive agent 6 disposed therebetween, and thereafter energization is carried out in a pressurized state. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for joining vehicles, and more particularly, to a method for electrical resistance spot welding with an adhesive interposed between two metal plates.

  In the body of an automobile, the weight reduction of the vehicle body is promoted from the viewpoint of improving the fuel efficiency and the operability of the vehicle. As an effective means for reducing the weight, replacement of a steel plate with an aluminum plate can be mentioned. Applications of this aluminum plate have expanded from lids such as trunk lits and doors attached to the vehicle body to parts that affect the rigidity of the vehicle body, such as roof panels.

  On the other hand, high-strength steel plates and ultra-high-tensile steel plates with a tensile strength of 980 MPa or more are adopted as rigid body parts such as pillars and roof rails as countermeasures against collisions and side collisions. There are also portions where it is difficult to replace the steel plate with the aluminum plate as described above in terms of strength and rigidity, and in such a portion, a structure of a dissimilar metal plate material in which a steel material and an aluminum plate are combined. Steel and aluminum plates differ greatly in physical properties such as melting point, thermal conductivity, resistance, etc., so it is difficult to use the most commonly used electrical resistance spot welding in automobile assembly, especially spot welding equipment between existing steel plates. It is said that. This is because an aluminum plate has a higher electrical conductivity and thermal conductivity than a steel material and requires a large current. Even if the welded portion is formed, since the potential difference is different between the steel material and the aluminum plate, the welded portion constitutes a local battery with an electrolyte such as water, so that there is a problem of so-called galvanic corrosion.

  As a method of electric resistance welding, there is a weld bond method in which spot welding and an adhesive are used in combination. This weld bond method has advantages in that fatigue characteristics, rigidity, and the like are improved, and that sealability is imparted around the welded portion and corrosion resistance is improved, as compared with spot welding alone. In JP-A-6-55277, an aluminum alloy-coated steel plate and an aluminum plate are joined by a weld bond method to form an Al-Fe alloy layer having a sealing property at a joining interface, and a high joining strength. A technique for obtaining the above has been proposed.

JP-A-6-55277

  A joining method when this weld bond method is used for joining a roof panel and a roof side rail of a vehicle body will be described with reference to FIGS. As shown in the figure, the roof side rail 1 portion of the side frame forms a closed cross section with a cab side outer 2 serving as an outermost plate and a roof rail inner 3 on the cabin side. For the purpose of improving rigidity and strength, a roof rail reinforcement 4 is arranged at the center so as to divide this closed section into two. As the plate material, the cabside outer 2 is made of an alloyed hot-dip galvanized mild steel plate, and the roof rail reinforcement 4 is made of an ultrahigh tensile steel plate.

  The roof side rail 1 and the aluminum alloy roof panel 5 are conveyed to a position setting step and set on a positioning jig. After setting to the jig, a thermosetting adhesive is applied to a portion where the cab side outer 2 and the roof rail reinforcement 4 are overlapped with each other on the vehicle body and the roof panel 5 is joined. Next, after the roof side rail 1 and the roof panel 5 are positioned at the welding position as shown in FIG. 10 by a positioning jig, they are energized with pressure by an electric resistance spot welder.

  The joined vehicle body unit is sent to a heating process for curing the applied adhesive, and proceeds to the coating process after the adhesive is cured. In addition, a coating sealer is separately applied to a joining region between the roof panel 5 and the cab side outer 2 in order to ensure a sealing property. FIG. 12 shows the state of the welded portion on the roof panel side after the above-described welding. Although the adhesive 6 exists around the welded portion, there is a region C that is partially interrupted from the welding position toward the outer circumferential direction, not the entire circumference. In addition, scattered marks D that were observed to have carbonized the adhesive 6 were observed at the outer peripheral edge of the discontinuous region C.

  In joining the steel plate and the aluminum plate, the interface portion of the aluminum plate is melted, and the bonding strength is obtained by causing diffusion between Al and Fe. Therefore, so-called scattering occurs in which the aluminum plate melts and scatters. In particular, the amount of scattering tends to increase as the supply current during welding increases. When this scattering occurs, as shown in FIG. 12, since the molten aluminum proceeds in a state of crossing the adhesive, there arises a problem that the sealing performance of the joint portion cannot be sufficiently ensured.

  It is an object of the present invention to prevent a sealing failure of a welded portion due to an adhesive by preventing the scattering at the time of spot welding from flying to the outside of the vehicle body in a method of spot welding a metal plate material with an adhesive interposed. is there.

  According to the first aspect of the present invention, there is provided a method for joining vehicle bodies, in which an adhesive is interposed between a joined portion located on the outer side of the first metal plate and the joined portion located on the inner side of the second metal plate. In the welding method for welding, an adhesive is interposed between the bonded portion of the first metal plate member and the bonded portion of the second metal plate member, and the bonded portion of the first metal plate member is welded from the welding position of both bonded portions. It is characterized by welding the joining positions of both of the joined parts by increasing the overlapping force on the end part side over the overlapping force of the first metal plate material other than the end part side.

  According to a second aspect of the present invention, there is provided a vehicle body joining method according to the first aspect of the invention, wherein a pressurizing means for increasing the superposition force is provided in advance, and during welding, the superposition force on the outside of the vehicle body at the welding position is increased by the pressurization means. It is said.

  According to a third aspect of the present invention, there is provided a vehicle body joining method according to the first or second aspect of the invention, wherein the first metal plate is an aluminum alloy plate and the second metal plate is a steel plate.

  According to a fourth aspect of the present invention, there is provided a vehicle body joining method according to any one of the first to third aspects, wherein the step formed on the end side of the joined portion of the first metal plate is pressed against the joined portion of the second metal plate. It is characterized in that the overlapping force on the end side of the bonded portion of the first metal plate material is higher than the overlapping force on the end portion side of the bonded portion of the first metal plate material.

  According to a fifth aspect of the present invention, there is provided a method for joining vehicle bodies, wherein the first metal plate member is a roof panel of the vehicle body and the second metal plate member is a roof rail of the vehicle body.

  According to the first aspect of the present invention, in the method of spot welding a plate material with an adhesive interposed, it is possible to prevent a seal failure by preventing the scattering that occurs on the side of the end portion of the joined portion that contacts the outside of the vehicle body. It becomes. In other words, by locally providing a difference in the overlapping force between the plate materials, it becomes possible to guide the molten metal in the direction of travel to the inside of the vehicle body, avoiding the end side where the electrolyte water enters, and it is scattered during welding. Even if this occurs, it is possible to prevent the adhesive seal on the outside of the vehicle body from being cut and to prevent water from entering the weld.

  According to the invention of claim 2, a pressurizing means for increasing the superposition force is provided in advance, and during welding, the superposition force on the outside of the vehicle body at the welding position is increased by the pressurization means. It can be provided.

  According to invention of Claim 3, when joining an aluminum alloy plate and a steel plate, the weight reduction of a vehicle body and rigidity ensuring can be made compatible, preventing generation | occurrence | production of the electrolytic corrosion based on an electrical potential difference.

  According to the invention of claim 4, it is possible to increase the overlapping force on the outside of the vehicle body at the welding position with a simple configuration in which a step is formed on the end portion side of the first metal plate material, and separately generate the overlapping force. Is no longer necessary.

  According to the invention of claim 5, it is possible to prevent a seal failure between the roof panel and the roof rail of the vehicle body.

  Hereinafter, the best mode for carrying out the present invention will be described based on the first embodiment.

  Embodiment 1 of the present invention will be described below with reference to the drawings. In this joining method, the same reference numerals are assigned to the members described in the background art.

  As shown in FIGS. 1 and 2, the body structure M of the wagon-type automobile includes a pair of left and right front pillars 7, a pair of left and right center pillars 8, a pair of left and right rear pillars 9, and a pair of left and right front pillars 7. A front header 10 for connecting the upper end portions of the rear pillars, a rear header 11 for connecting the upper end portions of the pair of left and right rear pillars 9, and a pair of left and right extending across the upper end portion of the front pillar 7 and the upper end portion of the rear pillar 9. A roof side rail 1 and a roof panel 5 are provided. Various members other than the roof panel 5 are made of steel plates. FIG. 2 is a plan view of the main part of the vehicle body structure M of the automobile shown with the roof panel 5 omitted.

  The roof panel 5 made of a 6000 series aluminum alloy plate has a stepped portion 5a and a raised portion 5b at the left and right ends, respectively. The front upper end of the vehicle body forms a closed cross-section structure with the front end portion of the roof panel 5 and the front header 10, and the rear end of the vehicle body forms a closed cross-section structure with the rear end portion of the roof panel 5 and the rear header 11. In addition, steel reinforcing plate members 12a to 12d are laid across a pair of left and right roof side rails 1 to reinforce the roof strength. The roof side rail 1 at the upper end of the vehicle body forms a closed section with the cab side outer 2 and the roof rail inner 3 on the cabin side, as in the prior art, and the roof rail reinforcement 4 is divided into two to divide the closed section. It becomes the composition arranged. The roof panel 5 is joined to the vehicle body by electrical resistance spot welding to the front header 10, the rear header 11, and the roof side rail 1.

  The electric resistance spot welding apparatus 13 that performs the spot welding will be described with reference to FIG. The spot welding device 13 is positioned and held in a state in which metal plate materials are overlapped when spot welding is performed with a robot 15 equipped with a welding gun 14, a control device 16 that drives and controls the welding gun 14 and the robot 15, and the welding gun 14. Positioning jig (not shown). The robot 15 is a general-purpose 6-axis vertical articulated robot, and a welding gun 14 is attached to the tip of the robot hand. The robot 15 moves the welding gun 14 to a welding operation position of a metal component held by a positioning jig and a standby position retracted from the welding operation position.

  The welding gun 14 has a U-shaped frame, and includes a first electrode 17 installed on the electrode support portion 21, a second electrode 18 installed on the electrode support portion 22, and a drive mechanism 19. The first electrode 17 and the second electrode 18 are arranged opposite to each other, and the driving mechanism 19 moves the electrode on the axis to control the pressurizing force and the distance between the first electrode 17 and the second electrode 18. In addition, as welding conditions, the current value that can be energized is set to 8K to 14KA, the applied pressure is set to 300 to 500Kgf, and the energization time is set to 0.05 to 0.3 seconds.

Below, the spot welding process of the roof panel 5 and the roof side rail 1 is demonstrated.
As shown in FIGS. 4 to 6, the flange portions 2a, 3a, 4a and the vehicle body outer flange portions 2b, 3b, 4b of the cab side outer 2, the roof rail inner 3, and the roof rail reinforcement 4 are assembled in the vehicle body. A closed cross section is formed in advance by spot welding or the like in the process. The cab side outer 2 is made of an alloyed hot-dip galvanized mild steel plate having a thickness of 0.8 mm, and the roof rail reinforcement 4 is made of a 980 MPa class high-tensile steel plate having a thickness of 1.4 mm.
After the vehicle structure M including the roof side rail 1 is set on the positioning jig, the one-component thermosetting epoxy adhesive 6 is applied on the flange portion 2a inside the vehicle body of the cab side outer 2 so as to cover the welding position. Apply. The adhesive may be other thermosetting adhesives such as urethane adhesives and acrylic adhesives, as long as electrical insulation can be ensured. The thickness of the adhesive 6 is about 100 μm.

  As shown in FIG. 5, the roof panel 5 separately set on the positioning jig is positioned with respect to the roof side rail 1. As described above, the right and left ends of the roof panel 5 on the outer side of the vehicle body are formed with the upright portions 5b at the outer edge portions, and the step portions 5a of about 300 μm are formed in the length corresponding to the adhesive 6 in the longitudinal direction of the vehicle body. It is formed across. As a state before welding, the bottom portion of the upright portion 5b of the roof panel 5 is in contact with the flange portion 2a inside the vehicle body of the cab side outer 2 via the adhesive 6, and the step portion inside the vehicle body from the upright portion 5b. The adhesive 6 is accommodated in the space between 5a and the flange portion 2a. The roof panel 5 is a 6000 series aluminum alloy plate having a thickness of 1.2 mm.

  After positioning in the positional relationship, welding is performed by the spot welding device 13. The welding gun 14 is moved, the electrodes 17 and 18 are moved closer to each other at the stepped portion 5a, and the stepped portion 5a of the roof panel 5 and the flange portion 2a of the cab side outer 2 are interposed with the adhesive 6 Then, 12KA is energized in the pressurized state. At this time, since the bottom of the upright portion 5b is pressed against the flange portion 2a of the cab side outer 2 via the adhesive 6 in advance by the pressure applied by the electrodes 17 and 18, the outer side of the vehicle body can stand up even if aluminum alloy scattering occurs. It is in a state of being sealed by the upper part 5b, and the traveling direction of the scattering is positively guided to the inside of the open vehicle body.

As shown in FIG. 6, the stepped portion 5a is crushed by the pressure applied by the electrodes 17 and 18, and the roof panel 5 and the cab side outer 2 are completely welded.
As shown in the sectional view of the welded portion in FIG. 7, nuggets indicated by a C region are confirmed between the cab side outer 2 and the roof rail reinforcement 4, and the structure of the A region of the roof rail reinforcement 4 is coarse. It was converted. Moreover, in the junction part of the roof panel 5 and the cab side outer 2, a nugget was confirmed in B area | region by the side of the roof panel 5, and it was observed that the interface has been diffusion-bonded.

  Next, a vehicle body joining method according to the second embodiment will be described with reference to FIG. In this joining method, the same members as those in the joining method of the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

The vehicle body joining method according to the second embodiment is performed using the same electric resistance spot welding apparatus 13 as that of the first embodiment, and the roof panel 5 is partially different in structure and welding procedure from the joining method of the first embodiment. It is.
The right and left ends of the roof panel 5 do not have the raised portions and stepped portions of the first embodiment, and a flat roof panel side flange portion 5c corresponding to the flange portion 2a of the cab side outer 2 is provided. Yes. Further, as a jig, a clamp means 20 is provided for sandwiching the roof panel side flange portion 5c and the flange portions 2a, 3a, 4a on the roof side rail 1 side.

After setting the roof panel 5 and the vehicle structure M on the positioning jig, the epoxy adhesive 6 is applied to the flange portion 2a on the vehicle body inner side of the cab side outer 2 so as to cover the welding position.
Next, the welding gun 14 and the clamping means 20 are moved so as to correspond to the welding position. The clamping means 20 is arranged at a position where the outer edge of the vehicle body can be clamped from the position where the roof panel 5 is welded.

  After the clamp means 20 clamps the roof panel side flange portion 5c and the flange portion 2a of the cab side outer 2 and the two come into contact with each other, the electrodes 17 and 18 start the pressurizing operation and are energized. The clamping force of the clamping means 20 is set so as to be higher than the pressing force of the electrodes 17 and 18.

  Since the clamping means 20 clamps the roof panel side flange portion 5c and the flange portion 2a of the cab side outer 2 in advance, and the pressing force is larger than the pressing force of the electrodes 17, 18, even if the aluminum alloy is scattered The outer side of the vehicle body is hermetically sealed by the clamping means 20, and the traveling direction of scattering is positively guided to the inner side of the opened vehicle body. Further, if the clamping force is made larger than the applied pressure, the same effect can be obtained even if the clamping operation of the clamping means 20 and the pressing operation of the electrodes 17 and 18 are performed simultaneously.

  In the second embodiment, in particular, it is not necessary to perform a pre-processing on the roof panel 5 side, so there is no need to change the existing vehicle structure, and the vehicle type can be easily developed.

  Next, a vehicle body joining method according to the third embodiment will be described with reference to FIG. The vehicle body joining method according to the third embodiment is partially different from the joining method according to the first embodiment in the structure of the welding gun 14.

  As shown in FIG. 9, the welding gun 14 is provided with electrodes 17 and 18 supported by the electrode support portions 21 and 22 and a drive mechanism 19 that moves the electrode 17 up and down. Further, gripping portions 23 and 24 are provided in the vicinity of the electrodes 17 and 18 of the electrode support portions 21 and 22. The tip of the grip portion 23 is set slightly longer than the tip of the electrode 17, and the tip of the grip portion 24 is the same length as the tip of the electrode 18.

  At the time of welding, the gripping portions 23 and 24 grip the roof panel side flange portion 5c and the flange portion 2a of the cab side outer 2, and then the electrodes 17 and 18 pressurize and energize the welding position. Even if scattering occurs, the outside of the vehicle body is closed by the gripping portions 23 and 24, and the traveling direction of the scattering is positively guided to the inside of the opened vehicle body.

  According to the third embodiment, it is possible to obtain the applied pressure for inducing the traveling direction of scattering toward the inner side of the vehicle body by using the applied pressure of the welding apparatus without changing the vehicle body structure. Further, by adding a mechanism that makes the gripping pressure variable to the gripping portions 23 and 24, it is possible to obtain a gripping force that matches the welding shape and plate material characteristics.

Next, a modification in which the above embodiment is partially changed will be described.
1) In the first, second, and third embodiments, the example in which the joining method of the present invention is applied to a wagon-type automobile body structure has been described. However, the present invention also applies to a sedan-type automobile body structure. A joining method can be applied.

2] In Examples 1, 2, and 3 described above, the joining technique of an aluminum alloy plate roof panel, an alloyed hot-dip galvanized mild steel plate cabside outer and a 980 MPa class high-strength steel plate roof rail reinforcement was described as an example. However, the present invention can be applied to a combination of other metal plate materials or a combination of the same metal plate materials. Further, two metal plates may be joined, and in particular, when joining metal plates having a low melting point, it is preferable to superimpose and join three or more. Furthermore, the application part is not limited to the joining of the roof panel and the cab side outer, and the joining method of the present invention can be applied to a part requiring countermeasures against corrosion such as an engine support member in the engine room.

3] In Examples 1, 2, and 3, the current value of spot welding is 12 KA, but it can be changed according to the number and the material of the metal plates. In particular, if it is in the range of 8K to 14KA, an existing spot welding apparatus for steel sheet can be used.

4] In the first embodiment, the step portion formed on the roof panel is 300 μm, but it can be set within a range that can accommodate the adhesive. If it is 1 mm or less, it is possible to absorb the distortion caused by the extension of the roof panel and improve the rigidity of the end portion. Moreover, although the step part was formed continuously from the front end of the roof panel to the rear end, it is also possible to provide a plurality of step parts individually corresponding to the welding position.

5] In the second embodiment, the clamping means may be integrated with the positioning jig, and a plurality of locations can be provided individually corresponding to the welding positions. Further, a clamp tip shape may be formed in accordance with the vehicle body structure.

6] In the third embodiment, the grip portion is formed on the electrode support portion in addition to the electrode. However, any structure may be used as long as the electrode pressing force by the drive mechanism can be shared, and the electrode support portion may be configured integrally with the electrode. it can.

7] In addition, those skilled in the art can implement the present invention in various forms with various modifications without departing from the spirit of the present invention, and the present invention includes such modifications. is there.

It is a disassembled perspective view of the vehicle body structure and roof panel of Example 1 of the present invention. It is a principal part top view of the vehicle body structure except a roof panel. It is a side view of an electrical resistance spot welding apparatus. It is sectional drawing of the roof rail before joining a roof panel and a roof rail. It is sectional drawing at the time of joining of a roof panel and a roof rail. It is sectional drawing after the completion of joining of a roof panel and a roof rail. It is an expanded sectional view of the joined part which carried out electrical resistance spot welding joining. It is sectional drawing at the time of joining of the roof panel and roof rail of Example 2 of this invention. It is a principal part enlarged side view of the periphery of the welding gun of the electrical resistance spot welding apparatus of Example 3 of this invention. It is sectional drawing at the time of joining the conventional roof panel and roof rail. It is sectional drawing after the completion of joining of the conventional roof panel and a roof rail. It is a state figure of the conventional roof panel side welding part.

Explanation of symbols

M Car body structure 2 Cab side panel 2a Flange part 4 Roof rail reinforcement 4a Flange part 5 Roof panel 5a Upright part 5b Step part 6 Adhesive 13 Spot welding device 14 Welding gun 17 First electrode 18 Second electrode

Claims (5)

In the vehicle body joining method of performing electrical resistance spot welding by interposing an adhesive between the joined portion located outside the vehicle body of the first metal plate material and the joined portion located inside the vehicle body of the second metal plate material,
An adhesive is interposed between the bonded portion of the first metal plate material and the bonded portion of the second metal plate material, and the end portion side of the bonded portion of the first metal plate material from the welding position of the both bonded portions. The vehicle body joining method is characterized by welding the joining positions of both of the joined parts by increasing the superposing force of the first metal plate material to be higher than the superposing force of the first metal plate material other than the end side.   2. The vehicle body joining method according to claim 1, wherein a pressurizing means for increasing the superposition force is provided in advance, and the superposition force on the outside of the vehicle body at the welding position is increased by the pressurization means during welding.   The method of joining vehicle bodies according to claim 1 or 2, wherein the first metal plate is an aluminum alloy plate, and the second metal plate is a steel plate.   The step formed on the end side of the joined portion of the first metal plate material is pressed against the joined portion of the second metal plate material, and the overlapping force on the end side of the joined portion of the first metal plate material is increased. The vehicle body joining method according to any one of claims 1 to 3, wherein the overlapping force is higher than that of the first metal plate material other than the end side of the joined portion.   5. The vehicle body joining method according to claim 3, wherein the first metal plate material is a roof panel of a vehicle body, and the second metal plate material is a roof rail of the vehicle body.