KR102143050B1 - self piercing rivet - Google Patents

Abstract

In order to prevent galvanic corrosion due to moisture penetration and improve corrosion resistance, the present invention is provided with a high-strength metal material with an outer circumferential surface formed in a cylindrical shape and an open lower part to sequentially press pierce a plurality of base metals stacked in the vertical direction. A shank portion including a cutting edge portion whose inner diameter decreases from a portion toward an upper side, and a shank extension portion integrally extending from an upper portion of the cutting edge portion; And a head body integrally extending in the vertical direction above the shank part, and a radial direction along the circumferential direction from the lower end of the head body so as to be in close contact with the upper end surface of the base material that is depressed by the shank part during rivet bonding. It provides a self-piercing rivet including a head portion including an extension blade protruding to be rounded to the outside.

Description

Self piercing rivet {self piercing rivet}

The present invention relates to a self-piercing rivet, and more particularly, to a self-piercing rivet in which galvanic corrosion due to moisture penetration is prevented and corrosion resistance is improved.

In general, in the automobile industry, in order to improve fuel economy due to environmental problems, weight reduction of the vehicle body using aluminum alloys and plastic materials, etc. is pursued, and for this purpose, a joining method that can replace the conventional spot welding for assembling the vehicle body has been developed. have. Thus, recently, a rivet joint method using self-piercing rivets has been utilized.

Here, the self-piercing rivet joining method uses a self-piercing rivet consisting of a head and a partially hollow cylindrical shank, and press-fitting the rivet into the object to be joined hydraulically or pneumatically without processing a hole in the object to be joined such as a steel plate. It is a method of joining the object to be joined through plastic deformation of the rivet.

1 is a schematic diagram showing a conventional self-piercing device.

1, the self-piercing device 4 has a C-shaped frame 2, a punch unit 3 disposed on the upper side of the frame 2, and faces the punch unit 3 It is provided including an anvil unit 4 to be disposed.

At this time, the punch unit 3 has a punch 3d and a clamper 3e driven in response to the anvil unit 4 by an operation rod 3c of a punch cylinder 3b provided in the punch housing 3a. ) Is provided.

In addition, an anvil die 4b on which a forming bone 4a is formed is provided on the upper surface of the anvil unit 4, and is mounted on the lower side of the frame 2 through a mounting rod 4c.

Here, a process in which the plurality of the objects to be joined 6a and 6b are joined proceeds as follows.

First, a plurality of the to-be-joined objects 6a and 6b are stacked and disposed between the punch unit 3 and the anvil unit 4, and a rivet 5 is supplied to the punch unit 3. In addition, when the punch cylinder 3b is driven forward by hydraulic pressure, a plurality of the joints 6a and 6b are clamped between the clamper 3e and the anvil die 4b.

At this time, when the punch cylinder 3b is continuously driven forward, the shank portion 5a of the rivet 5 is inserted through each of the joints 6a and 6b by the pressing force of the punch 3d. . In addition, as the plurality of the objects 6a and 6b and the shank 5a are expanded and deformed along the profile of the forming bone 4a, the plurality of the objects 6a and 6b are joined.

However, when a plurality of dissimilar materials to be joined, each provided with different materials, are stacked and arranged, moisture is introduced into the gap between the outer part of the rivet 5 and the material to be bonded. There is a problem in that galvanic corrosion occurs, resulting in a decrease in corrosion resistance and bonding strength.

Korean Patent Registration No. 10-1689572

In order to solve the above problems, the present invention is to provide a self-piercing rivet in which galvanic corrosion due to moisture penetration is prevented and corrosion resistance is improved.

In order to solve the above problems, the present invention is provided with a high-strength metal material having an outer circumferential surface in a cylindrical shape with an open lower portion, and sequentially pressurizes a plurality of base metals stacked up and down so that the inner diameter increases from the tip to the upper side. A shank portion including a reduced cutting edge portion and a shank extension portion integrally extending from an upper portion of the cutting edge portion; And a head body integrally extending in the vertical direction above the shank part, and a radial direction along the circumferential direction from the lower end of the head body so as to be in close contact with the upper end surface of the base material that is depressed by the shank part during rivet bonding. It provides a self-piercing rivet including a head portion including an extension blade protruding to be rounded to the outside.

In addition, the present invention is a cutting edge portion in which the inner diameter decreases from the tip portion to the upper side so as to sequentially press-pierce a plurality of base materials stacked up and down by being formed of a high-strength metal material with an outer circumferential surface formed in a cylindrical shape with an open lower portion And, a shank portion including a shank extension integrally extending from the upper portion of the cutting edge portion; And a head body integrally extending in the vertical direction above the shank part, and a radial direction along the circumferential direction from the lower end of the head body so as to be in close contact with the upper end surface of the base material that is depressed by the shank part during rivet bonding. An extension blade part protruding roundly outward, and a rotation formed at a position in which the outer peripheral profile extends radially outward from the lowermost end of the head body in close contact with the base material under the extension blade part. It provides a self-piercing rivet including a head portion including a variable fitting portion formed along a predetermined radius of curvature having a center.

Through the above solution means, the present invention provides the following effects.

First, when the self-piercing rivet is riveted to the base material, the shape of the variable joint is momentarily deformed by strong pressing force, but it is quickly spring-backed and is in close contact with the upper surface of the first base material. As the gaps between the gaps are substantially removed, moisture penetration is prevented. The galvanic corrosion caused by it can be prevented in advance, so that corrosion resistance and mutual bonding strength can be remarkably improved.

Second, the variable fitting part formed in a rounded outer circumferential profile under the extension blade part of the head part along a preset radius of curvature based on the center of rotation of the position extending radially outward from the lowermost end of the head body Since it is in close contact with the surface of the base material to be depressed, the corrosion resistance and precision of the bonding surface can be improved.

Third, in the process of piercing each base material by the shank part, as the piercing direction of the shank part is guided to bend radially outward by the inner circumference of the cutting edge part whose inner diameter decreases upwardly, the base material and the self-piercing rivet rivet each other. Can be joined.

1 is a schematic diagram showing a conventional self-piercing device.
Figure 2 is a side view showing a self-piercing rivet according to an embodiment of the present invention.
Figure 3 is a use example showing a state before the self-piercing rivet is pressure pierced to the base material according to an embodiment of the present invention.
Figure 4 is an example of use showing a state after the self-piercing rivet is press-pierced to the base material according to an embodiment of the present invention.

Hereinafter, a self-piercing rivet according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a side view showing a self-piercing rivet according to an embodiment of the present invention, Figure 3 is an example of use showing a state before the self-piercing rivet according to an embodiment of the present invention is pressure pierced to the base material.

As shown in FIGS. 2 to 3, the self-piercing rivet 200 according to an embodiment of the present invention includes a shank portion 110 and a head portion 120.

Here, the self-piercing rivet 200 is preferably understood as a fastening element provided for joining two or more base materials. In addition, the self-piercing rivet 200 may be applied to a production process of an RG3 EV vehicle, and its use is not limited thereto. In addition, the self-piercing rivet 200 according to an embodiment of the present invention does not require separate pre-hole processing on each of the base materials 4 and 5, and is joined by riveting each of the base materials 4 and 5 It is desirable to understand it as a fastening element to make. Hereinafter, a case in which the base materials 4 and 5 in which the self-piercing rivet 200 is provided in two layers according to an embodiment of the present invention are riveted together will be illustrated and described as an example.

Further, each of the base materials 4 and 5 may be provided with a metal sheet material such as an aluminum sheet or a steel sheet, and in some cases, may be provided with a non-metal material such as a composite material, plastic, rubber, or the like. In addition, each of the base materials 4 and 5 may be formed of the same material, or may be formed of different materials. Hereinafter, the first base material 4 disposed on the upper surface of each of the base materials 4 and 5 is provided with an aluminum material, and the second base material 5 is an ultra-high strength steel having a higher strength than the first base material 4 ( UHSS, ultra high strength steel) material, each provided with different materials from each other is shown and described as an example.

Here, the first base material 4 and the second base material 2 may each be provided with a predetermined thickness and may be stacked and disposed in a vertical direction. At this time, each thickness of each of the base materials 4 and 5 is preferably understood as a thickness in the vertical direction, and the thicknesses may be the same or may be formed differently.

On the other hand, the shank portion 110 is formed in a cylindrical shape with an outer circumferential surface in the form of an open lower portion, and may be provided with a metal such as high-strength steel, such as a high-strength material than each of the base materials 4 and 5.

Here, the shank portion 110 is formed with an inner diameter of the first base material 4 and the second base material 2 that are stacked in the vertical direction and are sequentially pressed and pierced upwardly from the tip part 111 so as to decrease the inner diameter. It is preferable to include a cutting edge portion 114 and a shank extension portion 117 integrally extending from an upper portion of the cutting edge portion 114.

In detail, the overall shape of the shank portion 110 including the cutting edge portion 114 and the shank extension portion 117 may be formed in a cylindrical shape whose outer circumferential surface is perpendicular to the upper surface of the head portion 120 .

In addition, it is preferable to understand that the total length h2 of the shank portion 110 including the tip portion 111 and the shank extension portion 13 is a vertical length perpendicular to the upper surface of the head portion 120 Do.

In addition, it is preferable that the shank portion 110 is provided with an open lower portion, and an opening space is formed inside the radial direction. At this time, when the self-piercing rivet 200 bonds each of the base materials 4 and 5, each of the base materials 4 and 5 deformed and flowed may flow into and flow into the opening space.

Further, the shank portion 110 may be opened in the vertical direction and at least one slit portion disposed along the circumferential direction of the shank portion 110 may be formed. Here, it is preferable to understand that the upper portion of the shank portion 110 is covered by the head portion 120 formed integrally with the shank portion 110.

On the other hand, the tip portion 111 is preferably formed along the circumferential direction at the lowermost end of the cutting edge portion 114 of the shank portion 110 to sequentially press each of the base materials (4, 5) in line or surface contact Do. That is, the tip portion 111 is preferably understood as a portion protruding in a sharp downward direction or rounded or flat surface at the lowermost end of the shank portion 110.

And, in some cases, the outer surface of the cutting edge portion 114 is formed under the shank portion 110 to induce piercing when pressed, but may be formed to be cut inclined at a predetermined angle from the outer side to the inner bottom in the radial direction. . In detail, the outer surface portion of the cutting edge portion 114 is from the upper outer surface of the cutting edge portion 114 toward the lower end of the cutting edge portion 114, that is, from the upper outer surface of the cutting edge portion 114. A cutting surface cut toward the tip portion 111 may be formed.

Accordingly, the tip portion 111 sharply protruding at the lowermost end of the cutting surface cut from the upper outer surface of the cutting edge portion 114 formed at the lower portion of the shank portion 114 toward the lower end portion is formed Since it is contacted from the upper surfaces of the base materials 4 and 5 and pierced by pressure, the processing performance of the product can be remarkably improved.

In addition, it is preferable that the inner diameter of the inner surface portion of the cutting edge portion 114 decreases toward the upper side so as to induce bending outward in the radial direction during the process of piercing the shank portion 110 to each of the base materials 4 and 5. . In addition, in some cases, a round surface 13 may be formed in which the inner circumferential profile of the cutting edge portion 114 is rounded in a convex shape in the radial direction.

Accordingly, the piercing direction of the shank portion 110 by the inner circumference of the cutting edge portion 114 whose inner diameter decreases as it goes upward in the process of piercing each of the base materials 4 and 5 by the shank portion 110 As the base material 4 and 5 and the self-piercing rivet 200 are guided to be bent outward in the radial direction, each of the base materials 4 and 5 and the self-piercing rivet 200 may be riveted to each other.

In addition, it is preferable that the shank extension 117 is integrally provided between the upper portion of the cutting edge portion 114 and the lower portion of the head portion 120. Here, the thickness of the shank extension 117 may be formed to have a uniform thickness toward the upper side, and in some cases, the thickness of the shank extension 117 is the shank portion 110, each of the base material (4, When pressing 5), it may be continuously increased toward the upper side of the shank portion 110. Moreover, the inner diameter of the upper end side of the shank extension 117 may be provided so as to decrease toward the upper side.

Here, in some cases, the outer circumferential surface of the shank extension 117 is formed substantially vertically with respect to each of the base materials 4 and 5, and the inner diameter of the shank extension 117 may be provided in a form that decreases upwardly. May be. In other words, the inner diameter of the shank extension 117 is continuously decreased as it goes upward, but the upper thickness k1 of the shank extension 117 is greater than or equal to the lower thickness k2 of the shank extension 117 It can also be formed.

In this case, a difference between the upper thickness k1 of the shank extension 117 and the lower thickness k2 of the shank extension 117 may be formed within a predetermined spacing range. For example, a difference between the upper thickness k1 of the shank extension 117 and the lower thickness k2 of the shank extension 117 may be formed in a range of 0.5 to 1.5 mm.

Accordingly, the outer circumferential surface of the shank extension 117 is formed substantially vertically with respect to each of the base materials 4 and 5, and the inner diameter of the shank extension 117 decreases upwardly, so that the shank portion Since excessive buckling of the shank portion 110 is prevented in the process of piercing each of the base materials 4 and 5 by pressure 110, durability and bonding performance of the product may be significantly improved.

On the other hand, the head portion 120 is preferably integrally provided on the upper portion of the shank portion 110, the head portion 120 is formed integrally extending in the vertical direction above the shank portion 110 The head body 121 and the upper end surface of the base material (4, 5) depressed by the shank portion 110 when the rivet is joined, that is, the head to be in close contact with the upper end surface of the first base material (4) It is preferable to include an extension blade portion 122 extending from the lower end of the body 121 to a rounded outward in the radial direction along the circumferential direction.

Here, referring to FIG. 2, in an embodiment of the present invention, the head body 121 is provided in a cylindrical shape on the upper portion of the shank portion 110 and is limited to a vertical length (h1) and a diameter (D0). It is preferable to understand, and the extension wing portion 122 is an outer portion of the head portion 120 protruding radially outwardly from the head body 121 and is limited to a vertical length (h1) and a diameter (D2) It is desirable to understand it as a part.

In addition, in an embodiment of the present invention, the upper portion of the head portion 120 including the head body 121 and the extension blade portion 122, which are not separately shown in the vertical direction and diameter, is the first base material ( It is desirable to understand that the shape can be changed in various shapes with the length and diameter in the vertical direction as a region that is not related to the region to be closely joined when the rivet is joined with 4).

Hereinafter, it is preferable to understand that the vertical length h1 of the head portion 120 according to an embodiment of the present invention is used as a vertical length excluding an upper region of the head portion 120, which is not separately shown. . In addition, the diameter (D1) of the extension wing portion 122 and the outermost protrusion width (D2) of the upper side of the extension wing portion 122 according to an embodiment of the present invention are not shown separately from the head portion 120 It is preferable to understand it as the diameter excluding the upper area of ). In addition, it is preferable to understand that the vertical length h1 of the head portion 120 according to an embodiment of the present invention is a vertical length perpendicular to the upper surface of the head portion 120, and the head portion 120 It is preferable that the vertical length of and the vertical length of the head body 121 are understood to have substantially the same meaning.

In addition, it is preferable that a variable fitting portion 123 formed in close contact with the first base material 4 and having an outer circumferential profile formed along a predetermined radius of curvature is provided below the extension blade portion 122. In this case, it is preferable to understand that the variable fitting part 123 is an outer peripheral surface formed to be rounded under the extension wing part 122.

Here, it is preferable that the center of rotation of the radius of curvature is virtually disposed at a position extending radially outward from the lowermost end of the head body 121 in a horizontal line. In addition, the rotation center may be virtually extended along the circumferential direction while being spaced apart by a predetermined length based on the radial center point of the head unit 120.

In addition, the outer circumferential profile of the variable fitting part 123 may be formed to be rounded in a concave shape inward in a radial direction along a preset radius of curvature based on the center of rotation of the radius of curvature.

Accordingly, the extension blade portion 122 of the head portion 120 along a predetermined radius of curvature based on a rotation center virtually disposed at a position extending radially outward from the lowermost end side of the head body 121 ) Since the variable fitting part 123 formed in a rounded outer circumferential profile at the bottom is in close contact with the upper end surface of the first base material 4 that is depressed by the shank part 110, the precision and bonding performance of the product will be improved. I can.

Here, when the variable fitting part 123 is formed with a radius of curvature of a numerical value greater than the above-described radius of curvature, a step difference between the upper surface of the head 120 and the upper surface of the first base material 4 after rivet bonding There is a risk of formation. On the other hand, when the variable fitting part 123 is formed with a radius of curvature of a numerical value smaller than the above-described radius of curvature, a gap between the variable fitting part 123 and the upper end of the first base material 4 is formed when rivet bonding. There is a concern that the bonding strength is lowered and the galvanic corrosion proceeds due to the inflow of moisture into the clearance gap.

Therefore, when the self-piercing rivet 200 is riveted to each of the base materials 4 and 5, the shape of the variable fitting part 123 is instantaneously deformed by a strong pressing force, but quickly springs back to the first base material 4 ), so that the gaps between each other are substantially removed, galvanic corrosion due to moisture penetration is prevented in advance, and corrosion resistance and mutual bonding strength can be remarkably improved.

Here, a numerical ratio between the diameter (D1) of the extension blade portion 122 and the radius of curvature may be formed to be 3.66 to 4.06:1. For example, when the diameter D1 of the extension blade part 122 is 8.7mm, the radius of curvature may be 2.25mm ^-1 . That is, when the diameter (D1) of the extension blade portion 122 is provided with 8.7 mm, the distance between the rotation center and the variable fitting portion 123 may be formed to be 2.25 mm.

In addition, a ratio between the diameter D1 of the extension blade portion 122 and the diameter D0 of the head body 121 may be formed in a range of 1.35 to 1.55:1. For example, when the diameter (D1) of the extension blade portion 122 is provided with 8.7mm, the diameter (D0) of the head body 121 may be provided with 6.0mm.

division Length(mm) Length(mm) Length(mm) D1 7.0 8.7 11.5 D0 6.0 6.0 6.0 Galvanic corrosion
Occurrence Occur Not occurring Occur

Table 1 is a table on whether galvanic corrosion occurs according to a change in the ratio between the diameter D1 of the extension blade part 122 and the diameter D0 of the head body 121. Here, when the diameter (D0) of the head body 121 is fixed, galvanic corrosion occurs according to the change in the diameter (D1) of the extension blade part 122, and the self-piercing rivet 200 By riveting the base materials 4 and 5 and setting the harsh conditions in which moisture is supplied to the rivet joint surface, the occurrence of galvanic corrosion was observed after the age period of 28 days.

As shown in Table 1, when the diameter (D1) of the extension wing portion 122 is provided with 8.7mm and the diameter (D0) of the head body 121 is provided with 6.0mm, that is, the extension wing portion When the ratio between the diameter (D1) of 122 and the diameter (D0) of the head body 121 is formed as 1.35 to 1.55:1, galvanic corrosion did not proceed.

In addition, a ratio between the vertical length h1 of the head part 120 and the outermost protrusion width D2 on the upper side of the extension blade part 122 may be 1.91 to 2.31:1. For example, when the vertical length h1 of the head part 120 is 2.85 mm, the outermost protrusion width D2 on the upper side of the extension wing part 122 may be 1.35 mm.

division Length(mm) Length(mm) Length(mm) h1 1.95 2.85 3.65 D2 1.35 1.35 1.35 Galvanic corrosion
Occurrence Occur Not occurring Occur

Table 2 is a table showing whether galvanic corrosion occurs according to a change in the ratio between the vertical length h1 of the head part 120 and the outermost protrusion width D2 of the upper side of the extension blade part 122. Here, it was shown whether galvanic corrosion occurred according to the change in the vertical length h1 of the head 120 while the upper outermost protruding width D2 was fixed, and the self-piercing rivets 200 were each After rivet bonding to the base material (4,5) and setting the harsh conditions in which moisture was supplied to the rivet bonding surface, the occurrence of galvanic corrosion was observed after the age period of 28 days.

As shown in Table 2, when the vertical length h1 of the head part 120 is provided with 2.85mm and the outermost protruding width D2 of the upper side of the extension blade part 122 is provided with 1.35mm That is, when the ratio between the vertical length h1 of the head part 120 and the outermost protrusion width D2 on the upper side of the extension wing part 122 is 1.91 to 2.31:1, galvanic corrosion does not proceed. Did.

Accordingly, the ratio between the diameter (D1) of the extension blade portion 122 and the diameter (D0) of the head body 121 is formed in 1.35 to 1.55:1, the vertical length of the head portion 120 ( As the ratio between h1) and the outermost protruding width (D2) on the upper side of the extension blade portion 122 is formed from 1.91 to 2.31:1, the shank portion 110 pressurizes each of the base materials 4 and 5 After that, between the outer surface of the extension blade 122 and the upper end surface of the first base material 4 disposed at the top of each of the base materials 4 and 5 may be in close contact.

Therefore, when the self-piercing rivet 200 is riveted to each of the base materials 4 and 5, the shape of the variable fitting part 123 is instantaneously deformed by a strong pressing force, but quickly springs back, while the first base material 4 ), so that the gaps between each other are substantially removed, galvanic corrosion due to moisture penetration is prevented in advance, and corrosion resistance and mutual bonding strength can be remarkably improved.

In addition, a ratio between the vertical length h1 of the head portion 120 and the vertical length h2 of the shank portion 110 may be set to 0.8 to 1.2:1. For example, the vertical length h1 of the head portion 120 and the vertical length h2 of the shank portion 110 may be substantially equal to 2.85 mm, respectively.

Here, the total length h1 of the head part 120 in the vertical direction including the upper region of the head part 120, which is not separately shown, is the shank part 110 It is preferable to understand that it is formed to be longer than the vertical length (h2) of ).

In addition, the ratio between the diameter (D1) of the extension blade portion 122 and the lengthwise summation length (h1 + h2) of the shank portion 110 and the head portion 120 may be set to 1.32 ~ 1.72:1. have. For example, when the diameter (D1) of the extension blade portion 122 is provided with 8.7mm, the lengthwise summation length (h1+h2) of the shank portion 110 and the head portion 120 is 5.70mm. I can.

In addition, the summed length h1+h2 of the shank part 110 and the head part 120 may be greater than the summed thickness of the first base material 4 and the second base material 2. That is, the entire length of the self-piercing rivet 200 may be provided so as to exceed the total thickness of each of the base materials 4 and 5 in the vertical direction.

Here, as the shank portion 110 is bent radially outward by the cutting edge portion 117 in the process of press-piercing each of the base materials 4 and 5, the self-piercing rivet 200 and each of the base materials 4 and 5 may be riveted to each other. Accordingly, the combined length (h1+h2) of the shank part 110 and the head part 120 is formed larger than the summed thickness of each of the base materials 4 and 5, and the shank part 110 As) is bent radially outward, the self-piercing rivet 200 and each of the base materials 4 and 5 are reliably riveted to each other, thereby improving manufacturing precision.

And, the outer surface profile is formed to be rounded in a convex shape outward in the radial direction on the upper side of the extension wing part 122 of the head part 120 which is not related to the riveting connection with the first base material 4 Additional can be formed. In detail, the clearance portion may be formed in a shape in which the diameter of the upper outer side of the extension blade 122 gradually increases as it goes upward from the variable fitting part 123, and then goes upward and the diameter decreases based on a preset point. have. Accordingly, the outer circumferential profile of the upper side of the head 120, which is not related to the rivet joint with the first base material 4, is formed in a rounded shape, so that the appearance of the product can be improved.

On the other hand, Figure 4 is an example of use showing a state after the self-piercing rivet according to an embodiment of the present invention is pressure pierced to the base material. At this time, the deformed self-piercing rivets 200a, deformed variable joints 123a, and deformed base materials 4a and 5a shown in Fig. 4 are self-piercing rivets shown in Figs. 2 to 3 (200 in Fig. 2). ), the variable joint (123 in Fig. 2), and each base material (4,5 in Fig. 3) are preferably understood as deformed as they are riveted.

Here, as the shank portion of the self-piercing rivet 200a presses each of the base materials 4a and 5a, each of the base materials 4a and 5a is depressed, and the deformed variable joint 123a and the deformed first It is preferable that the upper end surfaces of the base material 4a are in close contact with each other.

At this time, along the circumferential direction of the head part 120, the upper end surfaces of the variable fitting part 123a and the first base material 4a are in close contact with each other, so that between the head part 120 and the first base material 4 It is preferable that the clearance voids are substantially removed.

Accordingly, since moisture inflow between the self-piercing rivets 200a and each of the base materials 4a and 5a from the outside of the head 120 is substantially blocked, galvanic corrosion is prevented in advance, thereby remarkably improving the corrosion resistance of the bonding surface. Can be.

At this time, the terms such as "include", "consist of" or "have" described above mean that the corresponding component may be present unless otherwise stated, excluding other components It should not be construed as being able to further include other components. All terms, including technical or scientific terms, have the same meaning as generally understood by a person skilled in the art to which the present invention pertains, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted as being consistent with the contextual meaning of the related art, and are not to be interpreted as ideal or excessively formal meanings unless explicitly defined in the present invention.

As described above, the present invention is not limited to each of the above-described embodiments, and it is possible to be modified and implemented by those of ordinary skill in the art without departing from the scope of the claims of the present invention. And, these modifications are within the scope of the present invention.

200: self-piercing rivet 4: first base material
5: second base material 110: shank portion
111: tip portion 114: cutting edge portion
117: shank extension 120: head
121: head body 122: extension wing portion
123: variable fitting part

Claims (10)

A cutting edge portion whose inner diameter decreases from the tip portion to the upper side so as to sequentially press-pierce a plurality of base materials stacked in a vertical direction and provided with a high-strength metal material with an outer circumference formed in a cylindrical shape with an open bottom portion, and the cutting edge. A shank portion including a shank extension portion integrally extending from the upper portion of the branch portion; And
The head body integrally extending in the vertical direction on the upper portion of the shank portion, and a radially outer side along the circumferential direction from the lower end of the head body so as to be in close contact with the upper end surface of the base material that is depressed by the shank portion during rivet bonding. Self-piercing rivets including a head portion including an extension blade protruding to be rounded to extend. The method of claim 1,
The outer circumferential profile of the variable fitting portion formed in close contact with the base material under the extension blade portion is formed along a preset radius of curvature,
Self-piercing rivets, characterized in that the center of rotation of the radius of curvature is disposed at a position extending radially outward from the lowermost end of the head body in a horizontal line. According to claim 2,
Self-piercing rivets, characterized in that the numerical ratio between the diameter of the extension blade and the radius of curvature is 3.66 to 4.06:1. The method of claim 1,
Self-piercing rivets, characterized in that the ratio between the diameter of the extension blade and the diameter of the head body is formed in 1.35 to 1.55:1. The method of claim 1,
Self-piercing rivets, characterized in that the ratio between the vertical length of the head portion and the outermost protruding width of the upper side of the extension blade is 1.91 to 2.31:1. The method of claim 1,
Self-piercing rivets, characterized in that the ratio between the diameter of the extension blade and the summed length in the longitudinal direction of the shank and the head is set to 1.32 to 1.72:1. The method of claim 1,
Self-piercing rivets, characterized in that the ratio between the vertical length of the head portion and the vertical length of the shank portion is set to 0.8 ~ 1.2:1. The method of claim 1,
Self-piercing rivet, characterized in that the inner diameter of the cutting edge portion decreases upwardly so as to induce bending outward in a radial direction during pressure piercing. The method of claim 1,
Self-piercing rivets, characterized in that the outer side profile is formed to be rounded in a convex shape radially outward on the upper portion of the extension blade. A cutting edge portion whose inner diameter decreases from the tip portion to the upper side so as to sequentially press-pierce a plurality of base materials stacked in a vertical direction and provided with a high-strength metal material with an outer circumference formed in a cylindrical shape with an open bottom portion, and the cutting edge. A shank portion including a shank extension portion integrally extending from the upper portion of the branch portion; And
The head body integrally extending in the vertical direction on the upper portion of the shank portion, and a radially outer side along the circumferential direction from the lower end of the head body so as to be in close contact with the upper end surface of the base material that is depressed by the shank portion during rivet bonding. An extension blade part protruding roundly and a rotation center disposed at a position in which the outer circumferential profile extends radially outward from the lower end of the head body in close contact with the base material under the extension blade part Self-piercing rivet comprising a head portion including a variable fitting portion formed along a predetermined radius of curvature having a.

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