JP2000227199A - Gas filling welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently carry out filling up of gas into a round bottle body, by setting a tip brought into contact with a round side face of the bottle body to have a round radius of curvature equal to the round side face of the bottle body, in a means for shielding a circumference of a gas inlet including a weld pin. SOLUTION: A bottle body 1 holds a clamp from upper and lower sides by lifting a lower clamp electrode 6 by an elevating cylinder 8. A weld pin 3 is inserted into a gas inlet 2 of the bottle body 1. Making a metal seal 11 of a shield device 10 come down covers a circumference of the gas inlet 2 including the weld pin 3 to form a shield space 14. Then, the shield space 14 is supplied with high-pressure gas from a gas supply source 15 to fill the bottle body 1 with the high-pressure gas. In that case, an aperture of the metal seal is formed in a cylindrical shape and is set to a V-shaped knife edge or an inclined acute angle Q so that the aperture is made to be bitten into a round face of the bottle body 1 to form the completely covered shield space 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a small injection hole in a main body container such as a bottle body of an air bag or a cylinder body of a shock absorber (hereinafter, referred to as a bottle main body) mounted for safety of an automobile. Gas-filled welding method in which high-pressure gas or liquid or powder (hereinafter, referred to as high-pressure gas) is supplied from above, and the injection hole is covered with a welding pin or a plug, a spherical body, etc. (hereinafter, referred to as a welding pin) and sealed by projection welding. About.

[0002]

2. Description of the Related Art In the case of a shock absorber used in an automobile, for example, a gas filling welding apparatus generally known in the prior art, a bottle body is clamped vertically by a turntable or a conveyor or the like, and is sequentially transferred to a welding station. Compressed gas is supplied from the gas injection hole, a welding pin is inserted into the gas injection hole, the bottle body is pushed up, the outer periphery of the cylinder is clamped by the split electrode, and then the bottle body is pushed up to the upper electrode. There is known a method in which a welding pin is pressurized, a welding current is applied to an electrode, and the head of the welding pin is projection-welded to a gas injection hole to seal a gas.

[0003]

Conventionally, when supplying high-pressure gas to the bottle body, the tip of the metal seal is shielded by pressing the cutting edge of the metal seal at right angles to the plane of the gas injection part. If the cross section is circular, the metal seal cannot be shielded by applying it to the R side of the gas injection hole. Therefore, after smoothing the R side near the gas injection hole, press the metal seal against the flat surface. I had a gas shield. However, this type of conventional method is inefficient because of the man-hours required to partially flatten the R-shaped side surface of the pipe, resulting in an increase in cost.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a highly productive welding system capable of efficiently filling a bottle body having a circular cross section with gas.

[0005]

The present invention employs the following technical means to achieve the above object. That is, according to the first aspect of the present invention, a welding pin is inserted into a small gas injection hole formed in advance on the R side surface of the bottle main body, and the periphery of the gas injection hole including the welding pin is locally shielded by shielding means. Thereafter, when high-pressure gas is injected into the shielded space and high-pressure gas is supplied into the bottle from between the welding pin and the gas injection hole, the welding pin floating with the high-pressure gas flow is inserted into the shield. When the volume of the bottle body reaches a predetermined gas filling pressure, the electrode tip is operated and the head of the welding pin is pressed against the gas injection hole, and the pressure required for welding is further adjusted. In the gas-filled welding method of performing projection welding by applying a welding current to the bottle body, the tip of the shielding means that contacts the R side surface of the bottle body has an R curve substantially equal to the bolt body side surface. And having a radius.

In the gas filling welding method according to the first aspect of the present invention, a groove at the tip end of the shielding means has an acute angle or a V-shaped groove inclined toward an inner diameter.

According to the present invention, there is provided a gas filling welding method according to claim 1 or 2, wherein a tip edge of the shielding means is cut into an R side surface of the bottle main body, thereby shielding around the gas injection hole. Features.

[0008] The next invention is the gas filling welding method of one or two or three, wherein the shield means is a two-stage pressurizing method,
After the cutting edge of the shield means is cut into the R side surface of the bottle body by the single-stage pressurization, when the gas filling pressure of the bottle body reaches a preset gas filling pressure during the gas injection process. The two-stage pressurization, which is higher than the first-stage pressurizing force, is applied to improve the shielding performance of the thin bottle body.

[0009] By doing so, the tip of the metal seal can be pressed directly against the gas injection hole regardless of the R curved surface on the side of the bottle main body and the thickness of the bottle main body, and a complete shielding effect can be obtained. And can improve the welding quality.

Further, according to the present invention, in the gas filling welding method according to any one of claims 1 to 4, the bottle main body is clamped and held by a welding machine having a lower clamp electrode and an upper clamp electrode. The upper clamp electrode has both a work clamping surface and a power supply surface having a radius of curvature substantially matching the R side surface of the bottle body, and the lower clamp electrode and the upper clamp electrode include the R side surface of the bottle body including the vicinity of a welded portion. Is forcibly restrained, thereby preventing a change in the curvature of the bottle body.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of necessary components schematically showing a gas-filled welding apparatus for carrying out the method of the present invention. FIG. 2 is a front view schematically showing the welding device. FIG. 3 is an external view showing an embodiment of the welding pin.

In an embodiment of the present invention, a gas filling welding method for a gas filled bottle used for an air bag will be described as a typical example.

1 and 2, the bottle body 1 has a thickness of about 2 mm and is made of a cylindrical mild steel material having a cross section of about 25 mm in diameter. In the bottle body, both side openings 1a of the pipe are airtightly closed. A small gas injection hole 2 having a diameter of about 3 mm is previously formed in the side surface R of the bottle body. The gas injection hole substantially penetrates the pipe wall from a direction perpendicular to the axis of the bottle body, and communicates with the inside of the pipe hollow.

As shown in FIG. 3, the welding pin 3 has a shaft plug 4 inserted into the gas injection hole and a head 5 large enough to close the gas injection hole. Three projections P are formed in the head 5 in a tapered shape, and the projections P allow the gas to easily enter the bottle with the projection welded portion that is intensively heated and melted. When the shaft plug 4 of the welding pin 3 is inserted into the hole 2, it also serves as a gas inflow groove so that high-pressure gas can be injected into the bottle from between the protrusions P.

The bottle body 1 is securely clamped and held by a lower clamp electrode 6 and an upper clamp electrode 7 of the welding machine. The lower clamp electrode 6 and the upper clamp electrode 7 have both a work clamp surface U and a work power supply surface having a concave cross-sectional radius of curvature that is substantially compatible with the R side surface of the bottle body 1. 6 is clamped or released by an elevating cylinder 8 in the direction of the arrow to move up and down the distance between the work setting position and the gas injection / welding reference position.

The upper and lower clamp electrodes 6, 7 may be mutually clamp-driven by respective drive sources from above and below.

The upper clamp electrode 7 is a lower clamp electrode 6
The opening 9 is formed at a position corresponding to the gas injection hole 2 of the bottle main body 1 and is supported by the upper arm side of the resistance welding machine (not shown).
The opening 9 is configured so that the shield device is inserted therein.

The shield device 10 comprises a metal cylindrical metal seal 11 having a diameter larger than the outer diameter of the electrode tip 12.
The metal seal 11 has an inner space b having an inner diameter larger than the outer diameter of the electrode tip, and the inner space b and the rod-shaped electrode tip 12 inserted on a concentric circle are connected to the upper clamp electrode. 7 are arranged in the opening 9.

The electrode tip 12 and the metal seal 1
The electrode tip 12 is supported concentrically in an insulated state, and is supported by a pressure actuator (not shown) to move up and down in the metal seal. The inner diameter of the metal seal 11 and the outer circumference of the electrode tip 12 are O
It is hermetically sealed with a ring 13 or the like.

The upper clamp electrode 7 and the electrode tip 12
Is connected to the secondary circuit from the welding transformer T, and the necessary welding current is supplied after the specified gas filling pressure is supplied into the bottle.
It is supplied to the welding pin 3 via the electrode tip 12 and the upper clamp electrode 7.

The groove of the metal seal 11 has a cylindrical shape. The groove has an acute angle Q inclined toward the inner diameter of the V-shaped blade or its cylindrical seal, and the blade is bitten into the R side surface of the bottle body by two-stage pressurization by a pressurizing actuator. A small-sized shield space 14 completely shielded from the outside air is formed in the metal seal.

In particular, when the thickness of the bottle body 1 is small,
The bottle body may be deformed when the first-stage shield is pressed by the two-stage pressurizing cylinder, so the pressure inside the bottle is increased by the high-pressure gas during injection, and the pressure at the tip of the shield tip is increased again to increase shielding performance Improve.

The shield space 14 has a high-pressure gas supply source 15
Is supplied from a gas supply port 17 provided in the metal seal 11 via a gas supply circuit 16.

Hereinafter, the gas injection / welding operation by the apparatus for carrying out the method of the present invention will be described with reference to FIG.
First, the bottle main body 1 is set on the lower clamp electrode 6 waiting at the return work setting position by the lifting cylinder 8. Then, the lower clamp electrode 6 is raised to the welding reference position of the upper clamp electrode 7, whereby the bottle body is clamped and held from above and below (FIG. 4A).

Next, the bottle body 1 clamped and held
The welding pin 3 is inserted into the gas injection hole 2 of the first embodiment. Insertion of a welding pin is performed manually or automatically by a parts feeder (FIG. 4B).

When the welding pin 3 is inserted into the gas injection hole 2 of the bottle body 1, the metal seal 11 of the shield device 10 is lowered by the pressurizing actuator, and the seal groove is filled with the gas containing the welding pin 3. By surrounding the perimeter of the hole and locally shielding it from the outside air, a small-volume shield space 14
Is formed (FIG. 4C).

Next, the sealed space 14 is shielded.
A high-pressure gas having a gas pressure of, for example, 40 Mpa is supplied from the gas supply source 15 (FIG. 4D).

In this case, the thickness of the bottle body is, for example, 2
In the case of a thin type of about 1 mm, the first-stage shield pressure is applied at a pressure of about 15 KN at which the bottle body is not deformed. During the gas injection process, the supply gas in the bottle rises to a predetermined gas filling pressure. Then, the shielding pressure of the cutting edge of the metal seal is increased to 17 KN to further improve the shielding performance (FIG. 4C).

The high-pressure gas supplied to the shielded sealed space 14 is easily supplied into the bottle from the small gap formed by the projection P while the welding pin 3 is inserted into the gas injection hole 2. You.

That is, the tip of the electrode tip 12 in the metal seal faces the welding pin 3 in a non-contact state, and is slightly formed between the tip of the tip and the head 5 of the welding pin. The gap e is set to be shorter than the length of the welding pin 3, so that even if the welding pin 3 floats from the gas injection hole 2 by the high-pressure gas flow, the height at which the welding pin 3 floats at the tip of the electrode tip is regulated. As a result, gas injection can be performed efficiently while the welding pin 3 is fitted without falling out of the gas injection hole 2.

Therefore, the welding pin 3 only slightly floats from the gas injection hole 2 for the distance e, and only high-pressure gas is supplied into the shield chamber during that time. This high-pressure gas flow is supplied from the gas inflow groove formed by the projection P of the welding pin until the specified filling pressure of the bottle volume is reached.

Next, the pressure actuator is actuated to drive the electrode tip 12 under pressure to press the head 5 of the welding pin 3 against the periphery of the gas injection hole 2 of the bottle main body, thereby forming an electrode of 2 kN to 4 kN required for welding. A welding pressure of, for example, a current value of 8000 A to 10,000 A is supplied to intensively heat and melt the projection P of the welding pin 3 and the periphery of the gas injection hole 2 to complete the gas sealing welding (FIG. 4E). ). .

During the above operation process, when the bottle body 1 is particularly thin, the bottle volume expands under the influence of the high-pressure gas during gas injection, and the bottle body 1 bends or deforms under the influence of the impact force or heat during pressure welding. However, since the lower clamp electrode 6 and the upper clamp electrode 7 forcibly restrain or shape the entire side surface of the work including the welded portion with the work clamp surface U having the same curvature as the bottle body side surface R, Gas filling / welding can be performed without any deformation of the work.

When welding is completed in the above cycle, the lifting cylinder 8 is lowered, and the welded bottle body 1 is released from the upper and lower electrode clamps, returned to the original unclamping position, and carried out. The next new bottle body 1 is supplied to the lower clamp electrode after being carried out, and the welding operation is repeated in the same manner.

[0035]

As described above, according to the method of the first, second, and third aspects of the present invention, when a high-pressure gas is sealed in a bottle body, conventionally, the vicinity of the gas injection portion is once processed smoothly. After that, the metal seal was pressed against the smooth surface to fill the bottle with high-pressure gas and welded. On the other hand, the tip of the metal seal for gas injection was changed to the curvature of the R side surface of the bottle body. By forming the shield device approximately the same, the groove of the shield device can form the minimum necessary volume for gas injection and a complete shielding space directly on the R side surface of the gas injection part. As described above, it is not necessary to perform the smoothing process, and the gas filling process can be performed efficiently, the equipment is simple, and the problem of the capital investment cost can be solved.

According to the second and third aspects of the present invention, the tip groove of the shield means has an acute angle or a V-shaped groove inclined toward the inner diameter direction, whereby the tip groove of the shield means is formed. Can be easily cut into the R side surface of the bottle main body, whereby the shielding property can be dramatically improved with a minimum necessary volume at the gas injection site.

According to the fourth aspect of the present invention, particularly when the thickness of the bottle body is small, the first stage is pressed by a two-stage pressurizing method with a shield pressing force that does not deform the bottle body. The shielding pressure at the groove of the metal seal can be improved by increasing the shield pressure again together with the rise of the bottle filling pressure due to the high-pressure gas at the time of gas injection.

Next, according to the method of claim 5 of the present invention,
The upper and lower clamp electrodes forcibly constrain the entire side surface of the work including the welded part on the work clamp surface having the same radius of curvature as the R side surface of the bottle main body, so that the bottle main body is shaped without any curvature deformation. be able to.

In other words, the bottle body expands under the influence of the high-pressure gas during gas injection and is affected by impact force and heat at the time of pressure welding. A change in radial curvature can be prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view of necessary components showing an embodiment of a gas-filled welding apparatus for carrying out a method of the present invention.

FIG. 2 is a front view showing an embodiment of the apparatus for performing the method of the present invention.

FIG. 3 is an external view showing an example of a welding pin.

FIG. 4 is a diagram showing a gas filling / welding operation pattern according to the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bottle main body 2 Gas injection hole 3 Welding pin 4 Shaft plug 5 Head 6 Lower clamp electrode 7 Upper clamp electrode 8 Elevating cylinder 9 Electrode opening 10 Shielding device 11 Metal seal 12 Electrode tip 13 O ring 14 Shield space 15 High pressure gas supply Source 16 Gas supply circuit 17 Gas supply port P Projection Q Acute angle R Bottle body R side T Welding transformer U Work clamp surface

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F16F 9/43 F16F 9/43 F-term (Reference) 3E053 AA04 BA10 DA08 JA03 3E072 AA10 DA05 GA30 3J069 AA09 DD37 DD47 DD50

Claims (5)

[Claims] 1. A welding pin is inserted into a small gas injection hole formed in advance on the R side surface of a bottle body, and the periphery of the gas injection hole including the welding pin is locally shielded by a shield means. When a high-pressure gas is injected into the space and the high-pressure gas is supplied into the bottle from a gap between the welding pin and the gas injection hole, the welding pin floating by the high-pressure gas flow is connected to the electrode tip inserted into the shield. When the position of the bottle body reaches a predetermined gas pressure, the electrode tip is actuated to press the head of the welding pin against the gas injection hole, and to apply the welding force and welding current necessary for welding. In the gas-filled welding method for projection welding, the shielding means may have a tip in contact with the R side surface of the bottle body having a radius of curvature substantially equal to the R side surface of the bolt body. Characteristic gas-filled welding method. 2. The gas-filled welding method according to claim 1, wherein
The gas filling welding method according to claim 1, wherein a tip groove of the shield means has an acute angle or a V-shaped groove inclined toward an inner diameter direction. 3. The gas-filled welding method according to claim 2,
A gas filling welding method, characterized in that a tip edge of the shielding means is cut into an R side surface of the bottle main body, thereby shielding around the gas injection hole. 4. The gas filling welding method according to claim 1, wherein the shield is pressurized in a two-step manner by the shield means, and the tip of the shield means is moved to the bottle body by one-step pressurization. In the gas injection process, when the gas filling pressure reaches a preset gas filling pressure in the gas injection process after the bite into the R side surface, a two-stage pressurization that is higher than the first-stage pressurizing pressure is applied. In addition, a gas-filled welding method characterized by improving the shielding properties of a bottle body having a small thickness. 5. The gas filling welding method according to claim 1, wherein the bottle body is clamped and held by a resistance welding machine having a lower clamp electrode and an upper clamp electrode, and the lower clamp electrode and the upper clamp electrode are clamped. The clamp electrode is provided with a work clamping surface having a concave cross section having substantially the same R curvature as the side surface of the bottle body and a work power supply surface, and the lower clamp electrode and the upper clamp electrode include the vicinity of a welded portion of the bottle. A gas filling welding method characterized in that the R side surface of the main body is forcibly restrained, thereby preventing a change in curvature of the bottle main body which occurs at the time of gas injection and / or pressure welding.