Component manufacturing method and weld nut

Abstract

To provide a method of manufacturing a member which permits satisfactory clamping to a welding nut while suppressing difficulty of an operation.SOLUTION: A welding nut includes a screw hole, an opening of the screw hole and an end face which surrounds the opening. A method of manufacturing a member includes a step of arranging a positioning pin so as to protrude from a hole part of a workpiece, a step of arranging the welding nut to the positioning pin and a step of performing a projection welding of the welding nut and the workpiece. The welding nut arranged on the positioning pin causes the positioning pin to insert the screw hole, and a surrounding part is arranged so as to surround the positioning pin on an opening of the welding nut or on the neighborhood thereof.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a component and a weld nut. [Background technology]

[0002] A technology is known for welding a weld nut around a hole in a workpiece by projection welding. The weld nut in Patent Document 1 has a guide provided on the edge of the opening of the threaded hole, which is configured to fit into the hole in the workpiece. During projection welding, the guide determines the positioning, and projection welding is performed on the weld nut that is positioned so that the guide fits into the hole.

[0003] The guide closes the gap between the welding surface of the workpiece and the periphery of the opening of the threaded hole in the weld nut placed on the welding surface, preventing spatter from entering the threaded hole during projection welding. This reduces damage to the internal thread in the threaded hole caused by spatter, and as a result, the bolt can be securely fastened to the weld nut welded to the workpiece. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-283884 Summary of the Invention [Problem to be solved by the invention]

[0005] However, providing a guide for the weld nut as in Patent Document 1 may make the work more difficult. Specifically, the weld nut must be positioned so that the guide fits into the hole, making it difficult to flexibly determine the position where the weld nut is welded.

[0006] Furthermore, if the guide for the weld nut welded to the workpiece protrudes from the back side of the welded surface of the workpiece, the bolt fastened to the weld nut may come into direct contact with the guide, which could place a large load on the welded portion of the weld nut. Therefore, it is necessary to adjust the height of the guide for the weld nut so that it does not protrude from the back side of the welded surface of the workpiece. However, as a result of such adjustment, if the workpiece is thin, the guide will also be low, which could make it difficult to determine whether the guide is inserted into the hole when placing the weld nut on the workpiece.

[0007] An object of one aspect of the present disclosure is to enable good fastening of a weld nut while reducing the difficulty of the work. [Means for solving the problem]

[0008] One aspect of the present disclosure relates to a method for manufacturing a component, the method comprising: placing a positioning pin in a hole that penetrates a workpiece so that the positioning pin protrudes from the hole; placing a weld nut on the positioning pin that protrudes from the workpiece; and welding the weld nut placed on the positioning pin to the workpiece by projection welding. The weld nut has a threaded hole, an opening, and an end face. The threaded hole penetrates the weld nut. The opening is located at an end of the threaded hole. The end face surrounds the opening. The weld nut placed on the positioning pin that protrudes from the workpiece has an end face facing the workpiece, the positioning pin is inserted into the threaded hole, and a surrounding portion is arranged at or near the opening of the weld nut to surround the positioning pin.

[0009] According to the above configuration, the surrounding portion can cover the gap between the positioning pin and the inner peripheral surface of the threaded hole. This prevents spatter generated during projection welding from entering the threaded hole without interfering with the projection welding of the weld nut. This reduces the difficulty of the process and enables successful fastening of the weld nut.

[0010] In one aspect of the present disclosure, the circumference may be provided on the weld nut. According to the above configuration, the workload of positioning the circumferential portion during projection welding is reduced. In one aspect of the present disclosure, the circumferential portion may be deformable by fastening a bolt into the screw hole.

[0011] According to the above configuration, it is possible to prevent the circumferential portion from interfering with the fastening of the weld nut and the bolt. In one aspect of the present disclosure, the workpiece may be constructed from high-tensile steel.

[0012] In order to obtain sufficient joint strength when welding a workpiece made of high-tensile steel, the welding current value and welding temperature may be increased, but this may result in a large amount of spatter. In contrast, with the above configuration, even if the amount of spatter increases due to the increase in the projection welding current value, the spatter can be prevented from penetrating into the threaded hole. Therefore, the current value can be increased when projection welding a weld nut to a workpiece made of high-tensile steel, and the weld nut can be welded to the workpiece with sufficient joint strength.

[0013] One aspect of the present disclosure is a weld nut comprising a threaded hole, an opening, an end face, and a circumferential portion. The threaded hole passes through the weld nut. The opening is located at an end of the threaded hole. The end face surrounds the opening. The circumferential portion is provided at or near the opening. The weld nut is configured to be projection welded to a workpiece having a hole, and when projection welding is performed, a positioning pin is positioned to protrude from the hole in the workpiece, and the weld nut is positioned so that the end face faces the workpiece and the positioning pin is inserted into the threaded hole. The circumferential portion is configured to circumferentially surround the positioning pin.

[0014] According to the above configuration, the surrounding portion can cover the gap between the positioning pin and the inner peripheral surface of the threaded hole. This prevents spatter generated during projection welding from entering the threaded hole without interfering with the projection welding of the weld nut. This reduces the difficulty of the process and enables successful fastening of the weld nut.

[0015] In one aspect of the present disclosure, the circumferential portion may be deformable by fastening a bolt into the screw hole. According to the above configuration, it is possible to prevent the circumferential portion from interfering with the fastening of the weld nut and the bolt. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is an explanatory diagram showing a cross section of a weld nut, a workpiece, an electrode and a positioning pin in a welding device. FIG. [Figure 2] 10A and 10B are explanatory diagrams illustrating a method for joining a circumferential portion to a weld nut. [Figure 3] FIG. 10 is an explanatory diagram of fastening a bolt to a weld nut welded to a workpiece. [Figure 4] 1 is a flowchart of a method for manufacturing a member by projection welding. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that the embodiments of the present disclosure are not limited to the following embodiments, and various forms may be adopted as long as they fall within the technical scope of the present disclosure.

[0018] [1. Weld Nuts] Weld nut 1 is made of a metal such as iron, and is welded to workpiece 2 having hole 20 by projection welding (see FIG. 1). Weld nut 1 has threaded hole 10, first and second end faces 11, 12, flange portion 13, protrusion 14, and circumferential portion 15.

[0019] Threaded hole 10 is provided so as to pass through weld nut 1. An internal thread 10B is provided on the inner peripheral surface of threaded hole 10, allowing it to be fastened with a bolt. The first and second end faces 11, 12 are provided so as to surround the openings located at both ends of the screw hole 10. The first end face 11 is flat.

[0020] The flange portion 13 is provided so as to surround the opening 10A of the screw hole 10 in the first end surface 11. The protrusions 14 are portions that are melted by projection welding, and are configured as a plurality of protrusions provided on the first end surface 11 at approximately regular intervals so as to surround the opening 10A. The number of protrusions is determined appropriately.

[0021] [2. Orbital Division] The circumferential portion 15 is provided at a position near the opening 10A on the inner peripheral surface of the screw hole 10. The circumferential portion 15 is a ring-shaped portion having a flat shape that expands in the radial direction, and is provided so as to protrude from the inner peripheral surface of the screw hole 10 (see FIG. 1). The circumferential portion 15 is also provided so as to go around the inner peripheral surface.

[0022] Specifically, a groove 16 is formed around the edge of opening 10A of threaded hole 10 in first end face 11 of weld nut 1 so as to surround opening 10A (see FIG. 2). A wall portion 17 is formed adjacent to the outside of groove 16. Wall portion 17 protrudes from first end face 11 and surrounds groove 16. Then, with surrounding portion 15 positioned in groove 16, pressure is applied to wall portion 17, which is crushed and spread toward groove 16, thereby joining surrounding portion 15 to the inner circumferential surface of threaded hole 10.

[0023] Of course, the circumferential portion 15 may be joined to the inner surface of the threaded hole 10 by a method other than that described above, and the circumferential portion 15 may not be joined to the weld nut 1 but may be provided as a portion that protrudes from the inner surface of the threaded hole 10, for example, during the process of forming the weld nut 1 from the base material.

[0024] Moreover, the surrounding portion 15 may be provided, for example, further back in the screw hole 10. Note that the surrounding portion 15 is preferably located closer to the opening 10A than the internal threads 10B in the screw hole 10. The surrounding portion 15 may be located, for example, on the edge of the opening 10A, or may be joined to the first end face 11 on the outside of the screw hole 10 so as to cover the periphery of the edge of the opening 10A.

[0025] The surrounding portion 15 is made of a metal with low rigidity so that it is pressed and deformed by the bolt 4 that is screwed into the female thread 10B when the bolt is fastened into the screw hole 10 (see FIG. 3).

[0026] [3. Work] The workpiece 2 to which the weld nut 1 is welded is, for example, a plate-shaped member (see FIG. 1). More specifically, the workpiece 2 may be, for example, a thin plate for forming a vehicle body. However, the workpiece 2 is not limited to this, and the weld nut 1 can be welded to workpieces 2 of various shapes.

[0027] The workpiece 2 may also be made of, for example, high-tensile steel. Of course, the workpiece 2 is not limited to this, and may be made of various metals such as steel or iron. The workpiece 2 also has at least one hole 20 that penetrates the workpiece 2 in the thickness direction from the first surface 21 to the second surface 22.

[0028] [4. Manufacturing methods for components] The welding device 3 of this embodiment used for projection welding includes an electrode 30 and a positioning pin 31 (see FIG. 1). The positioning pin 31 is made of an insulating material (e.g., ceramic) and has a tapered shape. The electrode 30 has a hole 30A formed therein, and the positioning pin 31 is disposed in the hole 30A. The welding device 3 floats the positioning pin 31 by letting air out, causing the positioning pin 31 to protrude from the electrode 30.

[0029] In this embodiment, a member is manufactured by welding a weld nut 1 to the periphery of a hole 20 in a workpiece 2 by projection welding using a welding device 3. The method for manufacturing the member will be described below with reference to the flowchart in FIG.

[0030] In S100, the workpiece 2 is placed on the electrode 30 so that the holes 20 and 30A are aligned. At this time, the second surface 22 of the workpiece 2 abuts against the electrode 30. Then, floating is performed, and the positioning pin 31 is placed so that it penetrates the holes 20 and 30A and protrudes from the first surface 21.

[0031] In S105, weld nut 1 is placed on first surface 21 so that positioning pin 31 protruding from first surface 21 is inserted into threaded hole 10 (see FIG. 1). At this time, first end face 11 of weld nut 1 faces the area surrounding hole 20 on first surface 21 of workpiece 2. As described above, first end face 11 is flat, and a gap is formed between the area surrounding opening 10A on first end face 11 and first surface 21. Furthermore, protrusion 14 on first end face 11 abuts first surface 21 of workpiece 2 or faces first surface 21 with a small gap therebetween.

[0032] At this time, the circumferential portion 15 provided in the threaded hole 10 of the weld nut 1 is arranged so as to circumferentially surround the positioning pin 31, and the circumferential portion 15 covers the gap between the inner peripheral surface of the threaded hole 10 and the positioning pin 31. Specifically, the gap may be completely blocked by the circumferential portion 15, or a small gap may be formed between the circumferential portion 15 and the positioning pin 31.

[0033] In S110, projection welding is performed by passing a current through the protrusion 14 on the first end surface 11 of the weld nut 1 via the electrode 30. At this time, the flange portion 13 is pressed toward the workpiece 2, whereby the protrusion 14 comes into contact with the first surface 21 of the workpiece 2 and the protrusion 14 is placed in a pressurized state.

[0034] Thereafter, in the workpiece 2 to which the weld nut 1 has been welded, the bolt 4 inserted from the second surface 22 side is fastened to the weld nut 1 (see FIG. 3). When the bolt 4 is screwed into the internal thread 10B of the screw hole 10, the bolt presses the surrounding portion 15, causing it to deform.

[0035] [5. Modifications] In this embodiment, the wrapping portion 15 is provided on the weld nut 1, but the wrapping portion 15 and the weld nut 1 may be separate components. In step S105 of the manufacturing method shown in FIG. 4 described above, when the weld nut 1 is placed on the workpiece 2, the wrapping portion 15 may be positioned so that it wraps around the positioning pin 31 in the same manner at or near the opening 10A of the screw hole 10.

[0036] Specifically, for example, first, the surrounding portion 15 may be arranged so as to surround (in other words, be penetrated by) the positioning pin 31 protruding from the first surface 21 of the workpiece 2. Then, the weld nut 1 may be placed on the workpiece 2 so that the positioning pin 31 on which the surrounding portion 15 is arranged is inserted into the screw hole 10.

[0037] Alternatively, for example, the surrounding portion 15 may first be disposed at or near the opening 10A of the threaded hole 10 in the weld nut 1. Specifically, the surrounding portion 15 may be disposed on the inner peripheral surface of the threaded hole 10 or on the edge of the opening 10A, or the surrounding portion 15 may be disposed on the outside of the threaded hole 10 in contact with the first end face 11 so as to cover the periphery of the edge of the opening 10A. Then, the weld nut 1 may be placed on the workpiece 2 so that the positioning pin 31 is inserted into the threaded hole 10 and the surrounding portion 15.

[0038] Even in such a case, the gap between the inner peripheral surface of the screw hole 10 and the positioning pin 31 can be covered by the surrounding portion 15 in the same manner. [6. Effects] (1) According to the above embodiment, the surrounding portion 15 can cover the gap between the positioning pin 31 and the inner peripheral surface of the threaded hole 10. This prevents spatter generated by projection welding from entering the interior of the threaded hole 10 without interfering with the work of welding the weld nut 1 to the workpiece 2. This makes it possible to properly fasten the weld nut 1 while minimizing the difficulty of the work.

[0039] Here, by increasing the distance between opening 10A of threaded hole 10 and protrusion 14 on first end surface 11 of weld nut 1, it is possible to prevent spatter generated by projection welding from entering threaded hole 10. This allows the current value in projection welding to be increased, improving joint strength. However, increasing this distance increases the size of weld nut 1, which may reduce design freedom and increase the weight of components manufactured by projection welding. In contrast, according to the above embodiment, it is possible to prevent spatter from entering threaded hole 10 without increasing the size of weld nut 1.

[0040] There is also a known method of using the air used to float the positioning pin 31 to prevent spatter generated during projection welding from entering the threaded hole of the weld nut. Specifically, in this method, at least one groove is formed on the outer circumferential surface of the positioning pin, and air is allowed to flow out of the hole in the workpiece through the groove, thereby eliminating spatter heading toward the threaded hole.

[0041] However, this method requires the simultaneous floating and spatter removal of a large amount of air at high pressure, which increases costs and raises concerns about increased noise. Furthermore, because the pressure increases when floating the positioning pin, a greater force must be applied to the weld nut to pressurize the protrusion during projection welding. Furthermore, if the air flow from each groove in the positioning pin becomes uneven, the weld nut may shift position, resulting in inconsistent pressure on the protrusion. Furthermore, if the distance between the opening of the screw hole and the protrusion is long, a larger amount of air must be released to remove spatter, which increases costs.

[0042] In contrast to this, according to the above embodiment, it is possible to prevent spatter from entering the inside of the screw hole 10 without increasing the amount of air required for floating. Therefore, it is possible to prevent spatter from entering the inside of the screw hole 10 while suppressing increases in costs and noise.

[0043] (2) Furthermore, the wound portion 15 is provided on the weld nut 1. Therefore, the workload of placing the wound portion 15 during projection welding is reduced. (3) Furthermore, surrounding portion 15 can be deformed by fastening bolt 4 into threaded hole 10. Therefore, it is possible to prevent surrounding portion 15 from interfering with the fastening of weld nut 1 and bolt 4.

[0044] (4) Furthermore, when projection welding a workpiece made of a hard material such as high-tensile steel, the projection welding current value may be increased and the welding temperature may be raised to achieve sufficient joint strength. However, this may result in a large amount of spatter. In contrast, according to the above embodiment, even if the amount of spatter increases due to the increased projection welding current value, the spatter can be prevented from penetrating into the threaded hole 10. Therefore, a weld nut can be welded to a workpiece 2 made of high-tensile steel by projection welding with sufficient joint strength.

[0045] 7. Other Embodiments (1) In the above embodiment, weld nut 1 is provided with flange portion 13. However, weld nut 1 does not have to be provided with flange portion 13, and may have a shape such as a square nut or a hexagonal nut.

[0046] (2) The shape of the circumferential portion 15 is ring-shaped and has a flat shape that expands in the radial direction. However, the shape is not limited to this, and the circumferential portion 15 may have various shapes as long as it can cover the gap between the inner circumferential surface of the screw hole 10 and the positioning pin 31.

[0047] (3) Furthermore, in the manufacturing method of the member of the above embodiment, the positioning of the weld nut 1 is performed using the positioning pin 31 that protrudes from the electrode 30 by floating. However, the positioning pin 31 may be provided so as to protrude from the electrode 30 by a method other than floating. Specifically, for example, the positioning pin 31 disposed in the hole 30A may be displaced by a driving unit such as a motor, so that the positioning pin 31 protrudes from the electrode 30. Also, for example, the end of the positioning pin 31 may be joined to the electrode 30 so as to protrude from the electrode 30.

[0048] (4) Multiple functions of one component in the above embodiments may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. [Explanation of symbols]

[0049] 1...weld nut, 10...screw hole, 10A...opening, 11...first end surface, 14...projection portion, 15...circumferential portion, 2...workpiece, 20...hole portion, 21...first surface, 30...electrode, 31...positioning pin, 4...bolt

Claims

1. A method for manufacturing a component, comprising: disposing a positioning pin in a hole that penetrates the workpiece so that the positioning pin protrudes from the hole; placing a weld nut on the positioning pin protruding from the workpiece; and welding the weld nut disposed on the positioning pin to the workpiece by performing projection welding. The weld nut is a threaded hole passing through the weld nut; an opening located at an end of the screw hole; an end surface surrounding the opening, The weld nut placed on the positioning pin protruding from the workpiece has the end face facing the workpiece, the positioning pin inserted into the screw hole, and a surrounding portion is arranged at or near the opening of the weld nut so as to surround the positioning pin, The circumferential portion is deformable by fastening a bolt to the screw hole. Manufacturing method of components.

2. A method for manufacturing the member according to claim 1, The circumferential portion is provided on the weld nut. Manufacturing method of components.

3. A method for manufacturing the member according to claim 1 or 2, comprising: The workpiece is made of high-tensile steel. Manufacturing method of components.

4. A weld nut, a threaded hole passing through the weld nut; an opening located at an end of the screw hole; an end surface surrounding the opening; a circumferential portion provided at or near the opening, The weld nut is configured to be projection-welded to a workpiece having a hole, and when the projection welding is performed, a positioning pin is arranged to protrude from the hole of the workpiece, and the weld nut is arranged so that the end face faces the workpiece and the positioning pin is inserted into the screw hole, The circumferential portion is configured to circumferentially surround the positioning pin and is deformable by fastening a bolt into the screw hole. Welding nuts.

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