JP2000258356A - Spot welding part inspecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inspection method for certainly discriminating the welding quality of the spot welding part of first and second metal plate materials being the constitutional members of an alkali storage battery. SOLUTION: A conical projected wall part and a recessed cavity part 6 are formed to a first metal plate material 1 by bending and the first metal plate material 1 is superposed on a second metal plate material through the projected wall part to perform spot welding. In this case, a part (b) of a nugget B formed by spot welding is exposed to the recessed cavity part 6 and the quality of spot welding is discriminated on the basis of the diameter dimension or configurational difference of the exposed nugget part (b).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method for judging the quality of welding of a spot welded portion of an assembly having a spot welded portion such as a lid constituting a storage battery.

[0002]

2. Description of the Related Art A conventional method for inspecting a spot weld is the first method.
The metal plate material and the second metal plate material are polymerized, and in this state, electrodes are pressed at predetermined positions on both side surfaces of the polymer with a pressurizer at a constant pressure and a current is applied between the two metal plate materials with a constant power and spotted. Welding is performed to produce an assembly having a spot weld, and the quality of the weld in the weld is determined by checking the current value, voltage value, electric power, resistance value, etc. during the spot welding. Had been done.

[0003]

However, if the spot welding operation is repeated, the welding extreme of the spot welded portion may become weaker than a predetermined value for some reason.
Since there is no significant change in the current value, voltage value, electric power, resistance value, etc. measured during spot welding, unless there is an excessively large change, it is not possible to judge the quality of welding of the spot weld of each individual assembly. It was difficult. Therefore, the welding failure of the spot welding portion of the assembly having the spot welding portion is often overlooked and erroneously determined to be good. Therefore, there is an inconvenience of constructing a defective storage battery using such an assembly having poor welding. Therefore, it is desired to solve the conventional inconvenience of the inspection method of the quality of the welding of the spot-welded portion of the assembly and to develop a determination method capable of accurately determining the quality. An object of the present invention is to provide an inspection method that can reliably determine the quality of a spot welded part that satisfies such a demand.

[0004]

Means for Solving the Problems A part of the first metal plate is bent to form a convex wall protruding from one side thereof and a concave recess surrounded by the convex wall on the other side. When the first metal plate is overlapped on the surface of the second metal plate with the convex wall portion and the overlapped portion is spot-welded, spot welding is performed so that a part of the nugget generated by the spot welding is exposed in the concave portion. And forming an assembly having a spot welded portion, and then determining whether the spot welded portion is good or bad based on the size and / or shape of the diameter of the nugget portion exposed in the concave portion. Inspection method for spot welds. In carrying out the above-described method for inspecting a spot welded portion of the present invention, it is preferable to use an inspection device including illumination, a camera, an image processing unit, and a monitor. An assembly having a spot welded portion using the method for inspecting a spot welded portion of the present invention is a cover for a storage battery, a first metal plate material constituting the cover for a storage battery is a cap for a terminal, and a second cover.
The metal plate material is a rivet to which a laminated body mainly composed of a cover plate is bonded, and is applied to a spot welding portion inspection method for determining the quality of the spot welding portion of these plate materials.

[0005]

Next, an embodiment of the present invention will be described.
Description will be given based on the attached drawings. 1 to 5 illustrate a case where the present invention is applied to an alkaline storage battery lid A as an assembly having a spot weld. In the drawing, 1
Is a cap-shaped terminal cap serving as a terminal of a storage battery, and a first metal plate material made of iron plated with nickel, and 2 is a cover plate main body laminated body 3 applied to a rectangular battery can of the storage battery. A second metal plate made of nickel-plated iron, which is a rivet that is bound, and spot-welded with the first metal plate 1 superimposed on the upper surface of the second metal plate 2. Thus, the lid A is configured. The cover plate main laminate 3 includes a cover plate 3a as a main body, a gasket 3b interposed between an upper end horizontal plate portion 2a as a head of the rivet 2 on the upper surface of the cover plate 3a, and the cover 3a. An insulating plate 3c and a plate-shaped lead lug 3d bent in an L-shape are provided between the lower surface of the plate 3a and a caulked portion 2b at the lower end of the rivet 2. Reference numeral 4 denotes an elastic valve body. The valve body 4 is accommodated in the hollow portion of the cap-shaped cap 1 and is placed at a predetermined pressure on the upper surface of the horizontal plate portion 2a at the upper end of the rivet 2, and the lower surface of The center hole 2c of the rivet 2 acts so as to be normally closed at a predetermined pressure. 1b denotes an exhaust hole formed in the cap 1;

According to the present invention, when the first metal plate 1 is spot-welded to the second metal plate 2, a part of the flange 1a of the cap-shaped cap 1 which is the first metal plate is bent in advance. For example, at two symmetrical positions, for example, the convex wall portions 5 and 5 projecting downward from the back surface in a conical shape, a bowl shape, a dish shape, and the like, and the convex wall portions 5 and 5 on the upper surface thereof.
5, concave caps 6, 6 such as conical, bowl-shaped, and dish-shaped are formed, and the cap-shaped cap 1 is placed on the upper surface of a support substrate 8 having a hole 7 formed in the center. On the upper surface of the annular horizontal plate portion 2a at the upper end of the rivet 2 of the cover plate main laminate 3 placed on the upper surface, the convex wall portions 5 and 5 overlap and, as shown in FIG. A pair of upper electrodes 9 and 9 are brought into contact with upper edges of the outer peripheral edges of the left and right concave recesses 6 and 6 of the flange 1 a of the cap 1, while the lower electrode 10 is brought into contact with a caulked portion 2 b at the lower end of the rivet 2. In the center, these upper and lower electrodes 9, 9,
10, the first and second metal plate materials 1, 2 at a predetermined pressure.
, And a current is applied at a predetermined current and voltage to perform spot welding. In this case, according to the present invention, a part of the metal on the rivet side is melted, and at the same time, the convex wall portion 5 is melted and the nugget B generated by spot welding is formed by the first metal plate 1 and the second metal plate. Generated across two, but its nugget B
2 is spot-welded so as to be exposed in each of the concave portions 6 as shown in FIG. Thus, the lid A, which is an assembly obtained by spot welding the first metal plate 1 and the second metal plate 2, is formed.

As a result of many tests and researches over the years, the present inventor has found that the size or the diameter of the nugget portion b exposed in the concave portion 7 which is a part of the nugget B generated by such spot welding is described. And / or based on the shape, it was found that it was possible to determine whether or not the spot welding of the first metal plate 1 and the second metal plate 2 was performed well.

[0008] As an example of the determination of the quality of the spot welding, for example, a flange 1 of a cap-shaped cap 1 having a thickness of 0.3 mm is used.
a, a conical convex wall portion 5 protruding from the lower surface by 0.2 mm
And a conical concave portion 6 whose maximum value of the diameter of the open end surface surrounded by the convex wall portion 5 is 0.6 mm on the upper surface thereof. In the case of spot welding as shown in FIG. 3, the exposed portion b of the nugget B is formed in the recessed portion 6 by superimposing on the convex wall portion 5, pressurizing the upper and lower electrodes 9, 9, 10 and performing spot welding. When viewed from the top, as shown in FIG. 3 (a), when the shape is substantially a perfect circle and the diameter is 0.30 mm,
It may be determined that the spot welding of No. 2 is performed well. Further, when a longitudinal section is taken at a spot welded portion B of the lid A, as shown in FIG. 3B, the spot welded portion, that is, the nugget B, is connected to the first metal plate 1 side and the second It was generated evenly over the metal plate material 2 side, confirming that welding was performed well. In fact, as described below,
The tensile strength of the specimen was extremely high. The color of the nugget B was such that the metal was heated and melted at an appropriate temperature, and exhibited a good brown color.

FIG. 4 shows an example in which spot welding is defective. That is, as shown in FIG. 4A, when the diameter of the circular nugget portion b exposed in the concave portion 6 is as small as 0.25 mm as shown in FIG. Spot welding between the second metal plates 2 may be determined to be defective.
By the way, when the spot welded portion B is longitudinally cut, the nugget B has a large amount of the second metal plate 2, that is, the rivet 2, as shown in FIG. Since the amount of nugget B generated between the superposed surfaces of the plate materials 1 and 2 was small, it was confirmed that welding was defective. In some cases, the color of the nugget B looks blue-black, but this is not preferable.

FIG. 5 shows another example in which the spot welding is defective. That is, when observed from the upper surface, when the size of the diameter of the nugget portion b exposed in the concave recessed portion 6 is larger than 0.38 mm, the shape of the raised nugget portion b is as shown in FIG. Then, the peripheral circle is deformed into an irregular irregular shape. As described above, when the circular shape of the nugget portion b is broken, the spot welding may be determined to be defective. By the way, the longitudinal section of the spot weld is shown in FIG.
As shown in (b), the amount of generation on the first metal plate 1, that is, the cap-shaped cap 1 side is remarkably large, and the amount of generation of the nugget B extending between the overlapping surfaces of the two metal plates 1 and 2 is small. It was proved that the spot welding was poor. In this case, when the nugget B at the time of spot welding becomes too high in temperature, the molten metal may be scattered and adhere to the surrounding wall surface of the concave portion 6 as spatter b '. The spatter b '
Are usually observed in black because they cool rapidly.

As described above, according to the present invention, after the spot welding, the quality of the spot welding is observed from the upper surface of the nugget portion b which is exposed on the surface, and whether or not the diameter dimension exceeds a predetermined range is determined. The quality of the nugget part b is determined based on at least one of the determinations as to the presence or absence of the deformation of the shape. It may be determined whether or not it is not. FIG. 6 shows an example of an inspection apparatus that performs this inspection method. In the figure, a detecting device C includes a downward camera 12 disposed above a transport guide conveyor 11, an illuminator 13 for irradiating a lid A disposed on the transport guide conveyor 11, and image processing connected to the camera 12. Part 14
And a monitor 15 connected to the image processing unit 14. The exposed portion b of the spot welding portion B of the lid A is
2, the image is processed by the image processing unit 14, and the exposed portion b of the spot welding portion reflected on the monitor 15 is photographed.
The quality is determined based on the shape and the diameter. Because the success or failure of spot welding of many lids A, A,.
The detecting device C further arranges a pair of positioning sensors 16, 16 derived from the image processing unit 14 vertically as shown in the figure, so that the photographing can be performed when the lid A is located directly below the camera 12. Is preferred. In addition, in order to automatically remove defective products, a sorting controller 17 connected to the image processing unit 14 is provided, and the sorting controller 17 responds to the rejection signal from the image processing unit 14 by using its piston cylinder. It is preferable to provide equipment for activating 17a so as to make defective products sideways.

Embodiment A more specific embodiment of the present invention will be described in detail. Before assembling the lid A for the prismatic alkaline storage battery by spot welding, the flange 1a of the cap-shaped cap 1 having a thickness of 0.3 mm is placed on the left and right target positions by 0.2 mm downward from the back surface of the flange 1a. A conical convex wall portion 5 protruding from a convex wall portion and a conical concave portion 6 surrounded by the convex wall portion 5 having an open end face having a maximum diameter of 0.6 ± 0.1 mm. A large number of rivets 2 are prepared and prepared, and each cap-shaped cap is caulked and bonded to the cover plate main laminate 3 to have a thickness of 0.8.
On the upper surface of the flat head end plate 2a of ± 0.05 mm, the rubber valve 4 is housed in the inner space of the cap-shaped cap 1 with its convex wall portions 5 and 5 superposed and placed. A pair of left and right upper electrodes are pressed against the peripheral upper surfaces of the concave portions 6 and 6 on the left and right,
The caulked portion 2 at the peripheral edge of the hollow hole at the center of the rivet 2
b, with the lower electrode pressed against it, and applying a voltage 5
V, spot welding was performed in a state in which a part b of the nugget B generated by capacitor-type spot welding with a current of 2 KA for 10 ms was exposed inside each of the concave portions 6 and 6.
Repeat spot welding, spot welding parts B, B
A large number of rectangular alkaline storage battery lids having the following were assembled. Note that the cap-shaped cap 1 and the rivet 2 are made of iron plated with nickel.

Are transported intermittently by the transport guide conveyor 11 in order to determine the quality of spot welding by the detecting device shown in FIG. Sensed by the sensors 16, 16;
The trigger signal is sent to the image processing unit 14 just below the camera 12. The image processing unit 14 that has received the trigger signal sends a shutter signal to the camera 12,
The image processing unit 14 determines the diameter and shape of the video signal of the exposed portion b of the nugget B photographed by the camera 12, and sends the image to the monitor 15 at the same time. Further, the image processing unit 14 sends a NO or GO signal to the selection controller 17 after the determination is completed, and only when the NO signal is received, activates the cylinder 17a to remove the side exclusion unit (shown in the figure) from the conveyance guide conveyor. No) to extrude defective products to eliminate them.

In order to judge the quality of spot welding of the lid A, the shape and diameter of the nugget portion b of the spot welding, the presence or absence of spatter, and the presence of As a result of preliminarily examining the relationship with the tensile strength of the spot welded portion B, those having a tensile strength of 22 kg or more have a nugget portion b having a semi-spherical shape and a circular diameter as seen from the upper surface of 0.3 to 0.3 mm. It was found that a product having a size of 36 mm, which did not satisfy this condition, was a defective product, and the inspection by the inspection apparatus C was enabled based on this.

Table 1 below shows the inspection results of 1000 lids A described above.

[0016]

[Table 1]

Also, a large number of lids were separately manufactured, and the nugget portion b was formed into a semi-spherical shape, and the relationship between the size of the nugget and the tensile strength was examined.
The relationship shown in FIG. 7 was obtained. That is, the nugget part b
Is semicircular, the shape observed from the top is circular, and the diameter is in the range of 0.30 mm to 0.36 mm, the welding strength is 22 Kg to 25 Kg, which is large and good. When the diameter of the circle is less than 0.3 mm, the welding strength is reduced to 20 kg or less, which is a defective product. When the diameter exceeds 0.36 mm, the tensile strength is reduced even if the shape of the nugget is circular. It was found that the strength was reduced to 20 kg or less. When the diameter is 0.36 mm or more, the round shape of the nugget portion tends to be broken, or at the same time, spatter b 'tends to occur. In this case, the tensile strength is 15 kg or less, which is a defective product. .
Thus, the criterion for determining the quality of the spot welding is that the nugget part b has a semi-spherical shape and the diameter is 0.3 to 0.36 mm.
It has been found that the determination can be made by determining that those in the range of “good” are good and those that do not correspond to this are considered to be poor.

[0018]

As described above, according to the present invention, the first metal plate is provided with a convex wall portion such as a cone projecting to one side surface by bending and a concave portion surrounded by the convex wall portion on the other side surface. Is formed on the second metal plate material through the convex wall portion and is spot-welded so that a part of the nugget generated by melting between the two plate materials is exposed in the concave portion. Since spot welding is performed and the quality of the spot welding is determined based on the size and / or shape of the diameter of the exposed nugget portion, an effect that the quality of the spot welding can be reliably determined is provided. In the manufacture of the above, the lid, which is a constituent member thereof, is formed by spot welding a terminal cap, which is a first metal plate, and a rivet, which is formed by caulking and binding a lid plate main body laminate, which is a second metal plate, as described above. After producing and pot welding, can be used to determine the quality of the welding spot welds B of the lid. In this case, it is convenient that the quality of the spot welding can be determined using an inspection device including an illuminator, a camera, an image processing unit, and a monitor.

[Brief description of the drawings]

FIG. 1 is a cut-away side view of a main part when a spot welding method used for inspecting the quality of spot welding of the present invention is applied to a cover for an alkaline storage battery.

FIG. 2 is a longitudinal sectional view of a lid for an alkaline storage battery spot-welded according to the present invention.

FIG. 3 is a view showing a half portion of the lid, and FIG.
FIG. 3B is a top view of an example of the spot welded portion, FIG.
FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a view showing a half part of the lid, and FIG.
Is a top view of another example of the spot weld, FIG.
FIG. 4 is a sectional view taken along line IV-IV of FIG.

FIG. 5 is a view showing a half portion of the lid, and FIG.
FIG. 5 is a top view of still another example of the spot weld, and FIG.
FIG. 5B is a sectional view taken along line VV of FIG.

FIG. 6 is a side view of an example of a spot welding inspection apparatus used to carry out the spot welding inspection method of the present invention.

FIG. 7 is a graph showing the relationship between the diameter of a nugget part and its tensile strength.

[Explanation of symbols]

A Lid body having spot welds 1 First metal plate, terminal cap 1a Flange 2 Second metal plate, rivet 2a Head of rivet, horizontal plate at upper end of rivet 2b Lower crimped end of rivet 3 Cover plate Main laminate 3a Cover plate 5 Convex wall 6 Concave recess 9 Upper electrode 10 Lower electrode B Nugget
Spot welding part b Part of nugget, nugget C inspection equipment

Continuation of the front page F term (reference) 2F065 AA15 AA27 BB05 BB15 CC15 FF04 FF42 HH12 JJ03 JJ09 LL30 NN11 PP15 QQ21 RR05 RR08 TT03 2G051 AA90 AB13 AB20 CA04 CD07 DA06 DA13 EB01 5H012 AA07 BB02 JJ01 002 BB16 BB27 BB28 CC02 EE01

Claims (3)

[Claims] The first metal plate is partially bent and the first metal plate is bent.
A convex wall portion protruding from the side surface and a concave portion surrounded by the convex wall portion are formed on the other side surface, the first metal plate material is overlapped on the second metal plate material surface by the convex wall portion, and the overlapping portion is formed. In performing spot welding, after forming an assembly having a spot weld by performing spot welding so that a part of the nugget generated by the spot welding is exposed in the concave portion,
A method for inspecting a spot welded portion, wherein the quality of the spot welded portion is determined based on the size and / or shape of the diameter of the nugget portion exposed in the concave portion. 2. An inspection method for a spot welded portion, which uses an inspection device including an illuminator, a camera, an image processing unit, and a monitor to determine whether the spot welded portion is good or bad. 3. The assembly having the spot welded portion is a storage battery cover, the first metal plate constituting the storage battery cover is a terminal cap, and the second metal plate is a cover plate-based laminate. The method for inspecting spot welds according to claim 1 or 2, wherein the method is for determining whether or not welding of these spot welds is proper.