JPH0248155Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a welded joint of thin steel plates, and in particular relates to an optimal joint structure for use when the thin steel plates to be welded have a closed cross section. It is something.

[Conventional technology]

Conventionally, when producing a product by combining and welding thin steel plates of various shapes formed by press working, such as various automobile panels, the method of overlapping the thin steel plates and pressure welding by resistance welding is particularly popular in mass production. It is widely used as a technology. This method has the advantage that it is possible to join the thin steel sheets after correcting to some extent the poor precision of individual thin steel sheets due to elastic recovery, or the gaps between mating surfaces that occur during the joining process. However, on the other hand, resistance welding does not allow joining in a closed cross section, which poses a problem in terms of product design. On the other hand, when a fusion welding method such as arc welding is used for closed-section joints instead of pressure welding, the precision required for the pressed product becomes stricter and gaps inevitably occur during the joining process. The problem is that it becomes impossible to correct.

In connection with the present invention, when the left and right side plates of a fuel tank are welded with a pine loom, a folded part is provided at the joint end of one side plate, and the joint end of the other side plate is brought into contact with the folded part to perform pine loom welding. A method is known in which the overlapping allowance of both side plates is regulated to a predetermined dimension (Japanese Patent Application Laid-Open No. 1983-1999).
Publication No. 29446).

[The problem that the idea attempts to solve]

However, in the above proposed method, since the joint ends are simply brought into contact with the folded parts, although the overlapping margin of both side plates can be regulated, there is no restriction on the direction in which the overlapping joint ends move away from each other. There is virtually no power. Therefore, warpage and deformation of unwelded parts that occur during the welding process are unavoidable.
There is a possibility that a gap will be created between both joint ends, making it impossible to obtain a desired welded state. In order to prevent this, it is necessary to forcibly restrict the deformation of both joint ends using a special jig, or to support the overlapped joint ends from the side opposite to the welding process. Not only is it difficult to manufacture such a jig in reality, but the latter is virtually impossible in the case of welding thin steel plates that have a closed cross section.

The present invention focuses on the problems in the prior art described above and the problems in the method disclosed in Japanese Patent Application Laid-Open No. 50-29446, and eliminates the constraints on welded joint design by pressure welding, and uses special jigs etc. The purpose of the present invention is to make it possible to mass-produce welded joints with a closed cross-section configuration, which can easily achieve the desired joint state without using any welding.

[Means to solve the problem]

The welded joint for thin steel plates of the present invention, which meets this purpose, is made by attaching a part of the joint end to the joint end of one of two thin steel plates that constitute a closed cross section by welding, with a notch on both sides. By bending, a claw is formed that extends substantially perpendicularly to the other part of the joint end and then extends parallel to the other part, and between this claw and the joint end other than the claw, from the part of the claw to the other side of the claw. The joining end of the other thin steel plate extending over the joining end portion other than the claw is inserted, and in the inserted state, both thin steel plates are fusion-welded, for example, arc welded.

[Effect]

In such a welded joint, the position of one joint end of the thin steel plates to be joined during fusion welding is regulated by a claw provided at the joint end of the other thin steel plate. The claw extends substantially perpendicularly to the joint end and then extends parallel to the joint end, and the other joint end is inserted between the claw and the joint end other than the claw, so that The tip of the other joint end comes into contact with the vertically rising part of the claw, so that the overlapping margin of both joint ends is regulated to the target dimension, and at the same time, the part other than the claw is substantially parallel to the part. By being sandwiched between the connecting ends and the claws extending in the opposite direction, the joining ends are always regulated within a certain dimensional relationship in the direction of separation, and the generation of undesirable gaps is prevented. At the same time, since there are notches on both sides of the claw, the joint end on the side to be inserted can extend from the claw part to both sides, and the claw can extend in one direction (the direction in which the joint ends move away from each other). It is reliably regulated to a constant dimensional relationship in opposite directions, that is, in both directions, by parts other than the claws. Therefore, poor precision of the pressed thin steel sheet, deformation of the joint end that occurs when other parts of the thin steel sheet are welded, and deformation of the joint end that occurs during joint edge fusion welding are caused by the cooperation of the claws and parts other than the claws. The deformation of the joint and the gap between the joint surfaces are suppressed to a range that allows fusion welding.
Therefore, even if the thin steel plates to be joined have a closed cross section, it is possible to connect one joint end between the claws of the other joint end and the part other than the claws without using a special jig. Just by inserting it, the precision of the joint between both thin steel plates is maintained at the precision required for welding, and fusion welding becomes possible, making it possible to use fusion welding as a welding method that can be mass-produced with closed cross-section configurations. become. The ease of joining with a closed cross section expands the degree of freedom in product design, the closed cross section structure ensures product rigidity, and the ability to fusion weld eliminates the need for flanges, etc. for low resistance welding. As a result, products are made lighter and smaller. Furthermore, since the precision of the joints between thin steel plates is maintained within a certain level by the claws, the product precision in each process from pressing to joining requires particularly strict precision as in conventional fusion welding. The required accuracy is easily and stably ensured.

〔Example〕

Preferred embodiments of the welded joint for thin steel plates of the present invention will be described below with reference to the drawings.

1 to 3 show a welded joint of thin steel plates according to an embodiment of the present invention, which is applied to the front pillar of an automobile as shown in FIG. Front pillar 1 in Figure 1
The front pillar upper outer 2 and the front pillar upper inner 3 are assembled and welded together as two press-formed thin steel plates, and the cross section and plane of the joint are shown in Figures 2 and 2. It is shown in Figure 3.

The front pillar upper outer 2 and the front pillar upper inner 3 have concave cross sections 2a and 3a.
and the lower flange portion 2 of the concave cross-section portions 2a, 3a.
b, 3b, and concave cross-section parts 2a, 3
a with the concave surfaces facing each other, and the flange parts 2b and 3
A closed cross section is formed by overlapping the joint ends 2c and 3c at the upper ends of the concave cross sections 2a and 3a. Flanges 2b and 3b are joined by spot welding.

As shown in FIG. 3, the edge line 3d of the joint end 3c is formed in such a shape that cuts 4a and 4b are provided at appropriate intervals in the longitudinal direction A-A of the joint end 3c. Joint end 5 between cuts 4a and 4b
is bent at a substantially right angle to the joint end 3c of the remaining part and then bent again at the joint end 3c of the remaining part.
The nail is bent in a direction parallel to the nail.

Joint end 2c of front pillar upper outer 2
is the joint end 3c of the front pillar pin inner 3
and the claw 5 until the tip of the joint end 2c comes into contact with the side surface of the claw 5. This joint end 2
c extends from the claw 5 to a portion of the joint end 3c other than the claw 5 via the notches 4a and 4b on both sides of the claw 5. The joint end 2c is fusion welded to the upper surface of the joint end 3c by arc welding, arc spot welding, or the like.

In the welded joint of the thin steel plate constructed in this way, the front pillar upper outer 2 and the front pillar upper inner 3 constitute a closed cross section, and in the case of a product like the front pillar 1, it is functionally difficult for tools to enter. Since it is not possible to drill such holes, it is not possible to apply straightening force before or during welding. Then, the joint end 2c and the joint end 3
In order to properly arc weld c, the gap between the joint surfaces must be within a range that allows arc welding. In this invention, the front pillar atsupa outer 2
The joint end 2c is inserted between the joint end 3c of the front pillar inner 3 and the claw 5 during arc welding. The position is restricted in both the vertical and vertical directions. Therefore, the joint end 3c and the claw 5
By setting the gap into which the joint end 2c is inserted to an appropriate size, the mutual positional relationship of the joint ends 2c and 3c will be regulated below a certain level, resulting in poor precision of the single pressed product and lower flange 2.
Deformation of upper joint ends 2c, 3c that occurs when spot welding b, 3b, and joint ends 2c, 3c
Joint ends 2c and 3c in the process of arc welding
The deformation of and the gap between them are restricted to a range that allows arc welding.

Further, by bringing the tip of the joint end 2c into contact with the side surface of the claw 5, the position in this direction is also regulated and deformation is prevented.

In this way, by providing the claws 5, the deformation of the joint ends 2c and 3c and the gap between the joint surfaces can be suppressed to a range that allows arc welding, and even in the case of a long product such as the front pillar 1, arc welding is possible. This also reduces warpage, twisting, and other deformation of the entire product due to welding.

[Effect of idea]

As explained above, when using the welded joint of thin steel plates of the present invention, a claw of a specific shape having notches on both sides is provided at the joint end of the thin steel plate constituting a closed cross section, and the joint end other than the nail is By inserting the joint end of another thin steel plate between the two and fusion welding the joint ends, the deformation of the joint end and the gap between the joint surfaces can be controlled and kept within the range that can be fusion welded. It is possible to facilitate welding and joining in the cross-sectional configuration and expand the degree of freedom in product design, and it is also possible to ensure stable and good product accuracy in each process from pressing to joining. According to the present invention, when a closed cross section is constructed by using both the pressure welding method and the fusion welding method as shown in the embodiment, a particularly great effect can be obtained because the accuracy of the mating surfaces of the fusion welded part can be maintained during pressure welding. Further, when joining long products, a great effect can be obtained since warping and twisting of the entire product is reduced.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing a front pillar of an automobile to which a welded joint of thin steel plates according to an embodiment of the present invention is applied, Fig. 2 is a cross-sectional view of the front pillar shown in Fig. FIG. 3 is a partial plan view of the device. 1...Front pillar, 2...Front pillar top outer as a thin steel plate, 2b, 3b...
Flange, 2c, 3c...Joining end, 3...Front pillar pin inner as thin steel plate, 5...
nail.

Claims (1)

[Scope of utility model registration request] By bending a part of the joint end of one of the two thin steel plates forming a closed cross section by welding so as to have a notch on both sides, the joint end can be bent with respect to the other part of the joint end. Forming a claw that stands up at a substantially right angle and then extending in parallel, between the claw and the joint end other than the claw, from the part of the claw to the joint end part other than the claw on both sides of the nail. 1. A welded joint of thin steel sheets, characterized in that the joint ends of the other thin steel sheet extending across are inserted and the joint ends of both thin steel sheets are fusion welded.