JP7724165B2 - attachment - Google Patents

Description

The present invention relates to an attachment for spraying shielding gas that is installed around a spot welding electrode.

Spot welding is a type of resistance welding in which two workpieces are typically welded together by applying pressure with a rod-shaped electrode while a large current is passed through them, melting the workpieces using resistance heat. The molten part is called a nugget, and the electrode rod is usually cooled with cooling water. Spot welding is advantageous in places where the weld area is small and space is limited, and is frequently used in automobile frames, etc. Furthermore, because it produces a beautiful finish, it is often used in cases where appearance is important.

Electrodes used for spot welding are sometimes called tips or cap tips, and basically have a rod-shaped or cylindrical body, with tips that come in a variety of shapes depending on the application, such as flat, dome, radius, combinations of these, or offset.

Spot welding offers many benefits. However, one of the challenges is the discoloration that can remain around the dent, often referred to as "burn." This "burn" is caused by oxidation of the heat-affected zone during welding. When the workpiece is made of stainless steel, for example, this "burn" can adversely affect corrosion resistance, making it preferable to remove it. Furthermore, this type of burn treatment is often required for welds where aesthetics are important. Therefore, these "burns" require labor, time, and expense to remove. Specific treatment methods include chemical treatments using nitric hydrofluoric acid or a mixture of hydrochloric and nitric acid; electrolysis using an electrolyte; and mechanical methods using cutting. However, all of these methods require separate equipment and procedures for material management and post-processing, which is not just a removal process, but also imposes various burdens, including time, human resources, space resources, and costs.

In response to this situation, it has been proposed to provide a shielding gas injection device for spot welding in order to prevent the occurrence of burns (Patent Document 1, Patent Document 2). These shielding gas injection devices prevent oxidation and, ultimately, discoloration of the welding point by filling the area around the electrode with a shielding gas such as argon gas.

However, despite the disclosure of these technologies, unlike arc welding, shielding gas injection devices are rarely implemented in general use, and the reality is that the above process still requires a lot of effort, time, and money.

Japanese Patent Application Laid-Open No. 2000-197977 JP 2009-107000 A

Therefore, the present invention aims to provide a new shielding gas ejection device that can be installed around a spot welding electrode and can withstand practical implementation.

To solve the above problems, the spot welding electrode attachment of the present invention comprises an outer peripheral wall, an inner peripheral wall, and an upper wall that form a cylindrical body, and a rectifying section provided between the outer peripheral wall and the inner peripheral wall. The outer peripheral wall is provided with a shielding gas supply section to the rectifying section, and the rectifying section has a rectifying structure that rectifies the shielding gas supplied from the shielding gas supply section and causes it to flow downward. At least the outer peripheral wall, inner peripheral wall, and rectifying section are made of the same material, and the rectifying section has an integral component that is continuous with at least the outer peripheral wall or the inner peripheral wall.

Furthermore, the present invention provides an attachment for a spot welding electrode, which has an outer peripheral wall, an inner peripheral wall, and an upper wall that form a cylindrical body. A space is provided at the top between the space surrounded by the outer peripheral wall, inner peripheral wall, and upper wall, and a rectifying section is provided at the bottom. A shielding gas supply section is provided on the outer peripheral wall or upper wall to supply shielding gas to the space. The rectifying section has a rectifying structure that rectifies the shielding gas supplied from the shielding gas supply section through the space and causes it to flow to the bottom. At least the outer peripheral wall, inner peripheral wall, and rectifying section are made of the same material, and the rectifying section has an integral structure that is continuous with at least the outer peripheral wall or inner peripheral wall. It is also preferable that only one shielding gas supply section is provided. It is also preferable that the shielding gas supply section is in the shape of an obliquely cut cylinder, and that the shielding gas supply section is provided at the top.

Furthermore, the present invention provides an attachment to be placed around a rod-shaped electrode for resistance welding, comprising an outer peripheral wall and an inner peripheral wall that form a cylindrical body, and a rectifying section provided between the outer peripheral wall and the inner peripheral wall, a shielding gas supply section provided on the outer peripheral wall, the inner wall having no protrusions facing the internal space, the rectifying section having a rectifying structure that rectifies the shielding gas supplied from the shielding gas supply section and causes it to flow downward, and the outer peripheral wall, inner peripheral wall, shielding gas supply section, and rectifying section are made of the same material and are integrally formed as a whole.

It is also preferable that the outer peripheral wall has no protrusions facing outward other than the shielding gas supply portion, and that the inner peripheral wall has no protrusions facing toward the inner space.
It is also preferable that the housing has an opening extending from the outer peripheral wall to the inner peripheral wall for inserting a fixing member.

After careful consideration, the inventors of the present invention have concluded that the obstacles to implementing conventional technology are the need to simultaneously satisfy the requirements of space availability, movable area, burnt area removal, ease of work, efficiency, and cost. In particular, the space availability and movable area requirements for spot welding are extremely important factors, as they are closely related to the very reason why spot welding is chosen. At the same time, burnt area removal is also important, and insufficient removal will ultimately result in the need for reprocessing. Furthermore, unless ease of work, efficiency, and cost are met, on-site implementation is difficult. In light of these issues and after careful consideration, the present invention was completed.

The present invention is configured as an attachment to be attached around an electrode, and includes an outer peripheral wall and an inner peripheral wall that form a cylindrical body, and a flow straightening section provided between the outer peripheral wall and the inner peripheral wall. The attachment has an overall cylindrical/columnar shape, and the internal space formed by the outer peripheral wall and the inner peripheral wall serves as a flow path for the shielding gas. Therefore, the upper part is blocked by an upper wall or the like to prevent the shielding gas from escaping, and a shielding gas supply section is provided on the outer peripheral wall or the upper wall. Typically and preferably, the shielding gas supply section is a nozzle integral with the body, which receives the shielding gas and supplies it to the internal space formed by the outer peripheral wall and the inner peripheral wall. Note that the shielding gas supply section is not limited to a nozzle shape, and may be configured as an opening in the outer peripheral wall, with other configurations, such as inserting a separate pipe or the like into the opening, are not excluded. To minimize the impact on the space and mobility of the spot welding device, the shielding gas supply section is preferably provided on the upper part of the attachment, specifically at the top or above the longitudinal center of the outer peripheral wall.

The outer peripheral wall preferably has no protrusions facing outward other than the shielding gas supply section. This configuration is important for ensuring space and mobility while also ensuring ease of attachment and detachment and versatility. The inner peripheral wall is also configured without any protrusions facing the internal space, similarly ensuring space and mobility while also ensuring ease of attachment and detachment, avoiding contact with the electrode, quality, etc.

Furthermore, an opening for inserting a fixing member is provided, penetrating from the outer peripheral wall to the inner peripheral wall, making it possible to fix the attachment to the electrode. While known members and means can be used to fix the attachment without any particular limitations, it is preferable to use a member that can be fixed by inserting it into the opening, such as a screw. This configuration, which allows for fixation by simply inserting it into the opening, further improves ease of operation, efficiency, and cost-effectiveness, while minimizing restrictions on space and mobility. It is preferable that the area around the opening in the rectifying section be constructed with a sealed wall to prevent gas leakage.

The flow straightening section straightens the gas supplied from the shielding gas supply section, providing a longer laminar flow from the bottom. The flow straightening configuration used for this purpose can be any known configuration, but by manufacturing it as an integral part of the outer and/or inner peripheral walls, a higher shielding effect can be achieved without waste. Specific flow straightening configurations have been found to produce good welding results, not only with a configuration in which the cross section is a regular three-dimensional lattice, but also with an irregular porous configuration. However, when using an irregular porous configuration, care must be taken to ensure a design that ensures communication so that the gas from the supply section can be discharged from the bottom.

In the present invention, it is optimal for the outer peripheral wall, inner peripheral wall, and flow straightening section to be made of the same material and to be integrally constructed. Furthermore, in order to achieve the most suitable flow straightening configuration in the present invention, it is preferable to manufacture using a 3D printer. This configuration maximizes compactness and minimizes restrictions on space and mobility. It also ensures freedom in the shape of the flow straightening section, making it possible to achieve more suitable laminar flow.

In the present invention, the preferred diameter is determined by the electrode diameter, so it is not limited to a specific diameter. However, if the outer diameter is configured to be 30 mm or less, especially 24 mm or less, and the thickness of the outer and inner walls is 1 mm or less, especially 0.5 mm or less, and the thickness of the flow straightening portion is 5 mm, especially 3 mm or less, it will be compatible with most electrodes and will provide a high shielding effect while minimizing restrictions on the space and mobility of the welding equipment.

Multiple shielding gas supply sections can be provided to the flow straightening section. They are preferably formed in a nozzle shape, and preferably the nozzle consists of a first pipe section facing outward and a second pipe section facing upward, maintaining space and movability while avoiding the welding equipment. In order to even out the gas supply, it is preferable that two supply sections are positioned 180 degrees apart, and three supply sections are positioned at equal distances from each other, such as 120 degrees apart, to provide a uniform gas supply.

As another embodiment, a configuration with a single shielding gas supply unit can be provided. In this case, a space is provided above the rectifying unit to ensure optimal uniformity of gas supply to the rectifying unit. Furthermore, the attachment can be formed as an obliquely cut cylinder, with the space at its top and the rectifying unit at its bottom, with the shielding gas supply unit at the top. In other words, the longitudinal length of the attachment is configured to be greatest at the position of the shielding gas supply unit. A guide flow path may be provided within the space. This configuration is effective for ensuring a flow path, uniformity of gas supply to the rectifying unit, and compactness. The present invention can be used with various welding machines that perform resistance welding using spot welding electrodes, such as portable spot welding devices and single-sided spot welding devices, and can be used with lower, upper, or single-sided electrodes.

The attachment can be made from any material that can be shaped using a 3D printer, including, but not limited to, steels such as iron and stainless steel, titanium, and copper. However, for the purpose of shielding gas ejection, materials with high thermal conductivity, heat resistance, corrosion resistance, and hardness are preferred. For this reason, copper or copper alloys such as chromium copper are suitable, similar to the materials used for welding electrodes.

To use the attachment, attach it to the electrode and connect the shielding gas pipe to the shielding gas supply. With this invention, there are no unnecessary protrusions on the outer or inner circumference, and it can be easily attached to and detached from the electrode via the fixing opening. Spot welding is then performed under a spray of shielding gas. This process prevents burns and ensures good welding.

The attachment of the present invention maintains space and movable area while being easy to remove, work with, efficient, and cost-effective, making it suitable for practical implementation.

FIG. 1 is a perspective view showing an example of an attachment of the present invention. FIG. 2 is a front view of the attachment of FIG. 1 . FIG. 2 is a plan view of the attachment of FIG. 1; FIG. 2 is a bottom view of the attachment of FIG. 1 . FIG. 2 is a cross-sectional view of the attachment of FIG. 1 . FIG. 10 is a perspective view showing another example of the attachment of the present invention. FIG. 7 is a front view of the attachment of FIG. 6. FIG. 7 is a plan view of the attachment of FIG. 6; FIG. 7 is a bottom view of the attachment of FIG. 6 . FIG. 7 is a perspective view showing the inside of the attachment of FIG. 6. FIG. 2 is a perspective view showing a flow control section of the attachment of FIG. 1 . FIG. 7 is a perspective view showing a flow rectifying portion of the attachment of FIG. 6 . 2 is a diagram showing a state in which the attachment of FIG. 1 is installed on a spot welding device. FIG. FIG. 10 is a comparative diagram showing welding results. FIG. 10 is a comparative diagram showing welding results.

Embodiments of the present invention will be described with reference to the drawings.

Figures 1 to 5 are a perspective view, a front view, a plan view, and a bottom view showing an example of an attachment of the present invention.

The attachment 1 shown in Figure 1 is integrally formed entirely from a copper alloy and has a cylindrical, columnar shape including an outer peripheral wall 2, an inner peripheral wall 3, an upper wall 4, and a flow straightening section 5 provided between the outer peripheral wall 2 and the inner peripheral wall 3. Nozzles 6 and 7 are provided on the outer peripheral wall 2. The outer diameter of the attachment 1 is 18 mm, the inner diameter of the inner wall is 12 mm, the thickness of the outer peripheral wall 2 is 0.5 mm, and the thickness of the inner peripheral wall 3 is 0.5 mm. The length excluding the nozzles 6 and 7 is 21.5 mm, and the outer peripheral wall 2 has no outward protrusions, while the inner peripheral wall 3 has no inward protrusions.

Nozzles 6 and 7 are located 14.5 mm from the bottom end, and each has a first portion 8 facing outward and a second portion 9 parallel to the axis 10 of the attachment 1, ensuring space and mobility when installed. Furthermore, nozzles 6 and 7 are located 180 degrees apart on the outer peripheral wall 2, ensuring mobility and the introduction of uniform gas into the flow straightening section 5.

The flow straightening section 5 has an irregular porous structure (Figure 11) overall, but the voids ultimately connect to the lower part. Furthermore, because the flow straightening section 4 is integrally formed with the outer peripheral wall 2, inner peripheral wall 3, and upper wall 4, it is possible to provide laminar flow to the lower part with minimal volume, without creating any non-flow straightening areas, and without waste.

An opening 11 is provided in the outer wall of the attachment 1. It can be attached by fastening it to the electrode with a screw through this opening 11. The opening 11 penetrates from the outer wall 2 to the inner wall 3, and the area around the opening is made up of a sealed wall and has a screw receiving groove, ensuring ease of attachment and detachment and preventing unintended gas leakage.

Figure 13 is a photograph showing the attachment 1 according to this embodiment used in a spot welding machine. The attachment 1 is installed around the upper electrode of the spot welding machine. The attachment 1 is fixed to the periphery of the electrode with screws 13 provided in openings 11. The attachment 1 is installed so that shielding gas can be supplied to the nozzles 6 and 7 from an argon gas tank via hose 14. Removal is also easy; simply remove the hose 14 from the nozzles 6 and 7 and then remove the screws 12.

Figures 6 to 10 are perspective views, front views, plan views, bottom views, and perspective views showing another example of an attachment of the present invention. Since the main configuration is similar to that of Example 1, the same reference numerals are used to distinguish between them using "'" and differences will be primarily explained.

Attachment 1' comprises an outer peripheral wall 2', an inner peripheral wall 3', and an upper wall 4', and is configured as an obliquely cut cylinder overall. The outer peripheral wall 2', inner peripheral wall 3', and upper wall 4' define an internal space, which includes a space 12 at the top and a flow straightening section 5' at the bottom. A nozzle 6' is located at the top. Attachment 1' has an outer diameter of 22 mm, an inner diameter of 16 mm, an outer peripheral wall 2' thickness of 0.5 mm, and an inner peripheral wall 3' thickness of 0.5 mm. The outer peripheral wall 2' has no outward protrusions, and the inner peripheral wall 3' has no inward protrusions. The space 12 gradually widens from the gas inlet of nozzle 6 toward the flow straightening section 5', ensuring uniform gas supply to the flow straightening section 5'. Furthermore, the single nozzle 6' provides a unique design while offering advantageous space-saving and maneuverability for the welding machine. The length of the attachment at the nozzle supply section is 47.8 mm, and the length at its shortest point at the 180-degree separation position is 20.8 mm.

The flow straightening section 5' has a cross section with a regular lattice structure, and the entire section is connected to the lower section while varying in phase. Furthermore, the flow straightening section 5' is integrally formed with the outer peripheral wall 2', inner peripheral wall 3', and upper wall 4', which allows for the provision of laminar flow to the lower section with minimal volume, without creating any non-rectified gas portions, and without waste.

The results of normal welding (comparative example) without the attachment of the present invention, and welding with the attachments described in Examples 1 and 2 attached, are shown in Figures 14 and 15, respectively. In this example, SUS304 was used as the workpiece, and an ARO spot welder was used. The welding conditions were current: 6000 A (DC inverter), welding time: 600 sec (30 Hz), and pressure: 200 daN, with the exception of the presence or absence of an attachment and argon shielding gas.

In both the comparative examples in Figures 14 and 15, obvious discoloration can be seen around the dents. In contrast, there was no discoloration in either the welding performed with the attachments of Examples 1 and 2, and the quality achieved was such that no post-processing was necessary. Therefore, according to the present invention, an efficient burn prevention method is provided that simultaneously meets the requirements of space, movable area, burn removal, ease of operation, efficiency, and cost.

REFERENCE SIGNS LIST 1 Attachment 2 Outer peripheral wall 3 Inner peripheral wall 4 Upper wall 5 Flow straightening section 6 Nozzle 7 Nozzle 8 First section 9 Second section 10 Shaft 11 Opening 12 Space section 13 Screw 14 Hose

Claims (14)

An attachment for a spot welding electrode,
The device includes an outer peripheral wall, an inner peripheral wall, and an upper wall that form a cylindrical body, and a flow straightening section that is provided between the outer peripheral wall and the inner peripheral wall,
A shielding gas supply section to the flow straightening section is provided on the outer peripheral wall,
the rectifying unit has a rectifying configuration that rectifies the shielding gas supplied from the shielding gas supply unit and causes it to flow in a direction parallel to the axis of the electrode ;
At least the outer peripheral wall, inner peripheral wall, and flow straightening section are made of the same material,
An attachment for ejecting shielding gas, wherein the flow straightening portion has an integral component portion that is continuous with at least the outer peripheral wall or the inner peripheral wall. An attachment as described in claim 1, characterized in that the shielding gas supply section consists of multiple nozzles provided on the outer peripheral wall. An attachment for a spot welding electrode,
The cylindrical body has an outer peripheral wall, an inner peripheral wall, and an upper wall,
A space is provided at the top of the space surrounded by the outer peripheral wall, the inner peripheral wall, and the upper wall, and a flow straightening section is provided at the bottom.
a shielding gas supply unit for supplying a shielding gas to the space is provided on the outer peripheral wall or the upper wall;
the rectifying unit has a rectifying configuration that rectifies the shielding gas supplied from the shielding gas supply unit through the space and causes the shielding gas to flow in a direction parallel to the axis of the electrode ;
At least the outer peripheral wall, inner peripheral wall, and flow straightening part are made of the same material,
An attachment for ejecting shielding gas, wherein the flow straightening portion has an integral structure that is continuous with at least the outer peripheral wall or the inner peripheral wall. An attachment as described in claim 3, characterized in that only one shielding gas supply section is provided. An attachment as described in claim 4, characterized in that it is shaped like an obliquely cut cylinder, and the shielding gas supply section is provided at the top. An attachment described in any one of claims 1 to 5, characterized in that the outer wall has no outward protrusions other than the shielding gas supply section. An attachment described in any one of claims 1 to 6, characterized in that the inner peripheral wall does not have a protrusion facing the internal space. An attachment to be installed around a rod-shaped electrode for resistance welding,
The cylindrical body includes an outer peripheral wall and an inner peripheral wall, and a flow straightening portion provided between the outer peripheral wall and the inner peripheral wall,
A shielding gas supply unit is provided on the outer peripheral wall,
The inner wall does not have a protrusion toward the inner space,
the rectifying unit has a rectifying configuration that rectifies the shielding gas supplied from the shielding gas supply unit and causes it to flow in a direction parallel to the axis of the electrode ;
An attachment for ejecting shielding gas, in which the outer and inner walls, shielding gas supply section, and flow rectification section are all made of the same material and are integrally formed. An attachment as described in claim 8, characterized in that the outer wall has no outward protrusions other than the shielding gas supply section. An attachment described in any one of claims 1 to 9, characterized in that the outer diameter is 30 mm or less. An attachment described in any one of claims 1 to 10, characterized in that the thickness of the airflow control portion is 5 mm or less. An attachment described in any one of claims 1 to 11, characterized in that the thickness of the outer wall and inner wall is 1 mm or less. An attachment as described in any one of claims 1 to 12, characterized in that it has an opening for inserting a fixing member that penetrates from the outer peripheral wall to the inner peripheral wall. A welding device equipped with an attachment according to claims 1 to 12.