KR20220120018A - rivet screw drill - Google Patents

Abstract

To improve bearing performance through a double bearing structure, the present invention discloses a rivet screw drill for piercing and tapping a base material, comprising: a burring part, which includes a first burring part which is connected to a cutting edge part which is rotationally pressed against the material and has a round-shaped outer profile in section, and a second burring part which is integrally formed on an upper portion of the first burring part and has a round-shaped outer profile in section discontinuous with the first burring part, and which has a heat generation relief groove formed in a boundary area between the first burring part and the second burring part; a tapping part which is integrally connected to the upper portion of the burring part and has a screw thread formed on the outer surface for tapping the inner circumference of a hole formed in the material; and a head part which is integrally connected to an upper portion of the tapping part, extends outward in the radial direction of the tapping part, and allows for the selective mounting of a coupling tool for reciprocating movement and rotation on the upper portion.

Description

rivet screw drill

The present invention relates to a rivet screw drill, and more particularly, to a rivet screw drill having improved burring performance with a double burring structure.

In general, in a method of forming various structures by joining a plurality of base materials, for example, metal or non-metallic plates, sheets, and unspecified shapes, the superimposed base materials are mechanically formed using fastening elements such as bolts, nuts, and rivets. The method of joining is used.

Here, in the mechanical bonding method using a rivet, a hole is formed in the base materials to be joined through a drilling operation, and the rivet is plastically deformed while the rivet is inserted into the hole, and the base materials can be fastened.

And, as another mechanical bonding method, a method of blind riveting after hole processing a plurality of base materials is generally used.

On the other hand, in the case of bonding dissimilar materials with closed cross-sections such as aluminum or steel, there was a limitation in bonding dissimilar materials due to different melting temperatures between the base materials, and there were many difficulties in terms of design freedom.

In order to improve this, recently, a plurality of base materials are joined using a fastening element called FDS (Flow Drill Screw). Such fastening elements are also referred to in the art as friction stir rivets.

Here, for example, the fastening element of the FDS includes a head part mounted to the pressing/rotating device, a screw part integrally formed with the head part and having a thread formed on the outer circumferential surface, and a perforation part integrally connected to the screw part and perforating the base material. are doing

The bonding method using the fastening element of the FDS can rotate the head while pressing the head through the pressing/rotating device in a state in which the head is mounted on the pressing/rotating device, and the perforations are in contact with the superimposed base materials. Accordingly, the FDS fastening element may form holes in the base materials by friction of the perforations, and may integrally bond the base materials by screwing the base materials through the threaded portion.

However, the blind joining method as described above requires processing a free hole in the base material to be joined, and in the joining method using the FDS fastening element, when the base material of high tensile steel is joined, the piercing ability of the FDS fastening element to the base material is reduced. After a free hole was machined in the base material as it was limited, the base material was joined with an FDS fastening element.

Accordingly, in the prior art, in the case of the mechanical bonding methods as described above, since a process for separately drilling a free hole in the base material is added, hole processing cost may be added due to the addition of the process, and there is a problem that productivity and workability are lowered. there was.

In addition, in the prior art, because the radius of the burring part of the FDS fastening element is smaller than the radius of the part where the thread is tapped, the area and the formation angle of the thread formed by tapping on the base material are not uniform, so the precision of the product is slightly lowered. there was

Furthermore, in the case of forming a perforation in two or more base materials in the conventional FDS fastening element, when deformation and damage occur as the burring part is heated by excessive heat when burring the first base material, it is impossible to burr the second base material, so the burring performance is lowered There was a problem being

Korean Patent Publication No. 10-2016-0125148

In order to solve the above problems, an object of the present invention is to provide a rivet screw drill having improved burring performance with a double burring structure.

In order to solve the above problems, the present invention is a rivet screw drill for piercing and tapping a base material, a first burring part connected to a tip that is rotationally pressed to the base material and formed in a rounded outer surface profile in cross section, and a second burring part integrally formed on an upper portion of the first burring part and having a cross-section formed in a discontinuously rounded outer surface profile with the first burring part, and a boundary region between the first burring part and the second burring part a burring portion in which a heat escape groove is formed; a tapping part integrally connected to the upper part of the burring part and having a thread for tapping the inner periphery of the perforation formed in the base material on the outer surface; And it provides a rivet screw drill integrally connected to the upper part of the tapping part, the rivet screw drill including a head part extending outward in the radial direction of the tapping part and selectively mounting a joint tool for reciprocating movement and rotation on the upper part.

In addition, in the present invention, in the rivet screw drill for piercing and tapping the base material, the center of rotation is connected to the tip that is rotationally pressed to the base material and the cross section is arranged at a position extending from the uppermost side in the radial direction outward in the horizontal line. A first burring portion formed in a rounded outer surface profile along a first radius of curvature having a first burring portion integrally formed on an upper portion of the first burring portion and formed in a discontinuously rounded outer surface profile with the first burring portion in cross section. It is larger than the first radius of curvature and includes a second burring portion formed along a second radius of curvature having a center of rotation disposed at a position extending from the uppermost side in a radial direction outward on a horizontal line, the first burring portion and the second a burring part in which a heat escape groove is formed along the circumferential direction in a boundary region between the burring parts; a tapping part integrally connected to the upper part of the burring part and having a thread for tapping the inner periphery of the perforation formed in the base material on the outer surface; And it provides a rivet screw drill integrally connected to the upper part of the tapping part, the rivet screw drill including a head part extending outward in the radial direction of the tapping part and selectively mounting a joint tool for reciprocating movement and rotation on the upper part.

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

First, the perforation is first pierced in the base material, and then the perforation is expanded through the burring part of the two-stage round structure. The contact area between the first burring part and the second burring part and the base material is substantially increased, so that fastening strength and durability may be improved.

Second, the heat escape groove for frictional heat cooling is formed in the boundary region between the first and second burring parts along the circumferential direction to prevent deformation of the burring part due to overheating during the piercing process, so that the piercing performance and durability can be significantly improved. have.

Third, after the first burring part formed to be rounded with the first radius of curvature pierces the base material, the second burring part of the second radius of curvature formed as a discontinuously rounded outer surface profile with the first burring part expands the perforation of the base material. The short structure reduces frictional heat at the initial stage of piercing, and the manufacturing precision of the tapping screw thread formed in the perforation of the base material can be improved.

Fourth, the upper part of the molten coating part is melted by the rotational friction force in the hardening guide groove that is recessed upward along the circumferential direction from the inner end of the seating step, and then hardened and formed, and the lower part is closely coupled between the lower surface of the seating step and the base material, so galvanic corrosion As this is minimized, durability can be remarkably improved.

1 and 2 are perspective views showing a rivet screw drill according to an embodiment of the present invention.
Figure 3 is a side view showing a rivet screw drill according to an embodiment of the present invention.
Figure 4 is a side cross-sectional view showing the use state of the rivet screw drill according to an embodiment of the present invention.

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

1 and 2 are perspective views showing a rivet screw drill according to an embodiment of the present invention, Figure 3 is a side view showing a rivet screw drill according to an embodiment of the present invention, Figure 4 is an embodiment of the present invention It is a side cross-sectional view showing the state of use of the rivet screw drill according to

1 to 4 , the rivet screw drill 200 according to an embodiment of the present invention includes a burring part 110 , a tapping part 120 , and a head part 130 .

Here, the rivet screw drill 200 is preferably understood as a fastening element provided for piercing and tapping at least two or more base materials (not shown). In addition, the rivet screw drill 200 may be applied to a vehicle body assembly process of integrally bonding panels for a vehicle body. In addition, the base material (not shown) is not necessarily limited to including a body panel, and may include various body structures such as body members and frames, but is not limited thereto.

In addition, the rivet screw drill 200 may be provided with a metal material, such as high-strength steel, which is higher than that of the base material (not shown), and the base material (not shown) is a metal sheet material such as an aluminum sheet or a steel sheet. may be provided, and in some cases, may be provided with a non-metal material such as a composite material, plastic, rubber, or the like. Moreover, the base material (not shown) may be provided with the same material of the same kind to each other, and may be provided as a plate material of different materials.

At this time, in an embodiment of the present invention, a case in which a base material (not shown) including the same or different material of the closed cross-section is joined by a mechanical bonding method will be described as an example. That is, the rivet screw drill 200 according to an embodiment of the present invention is understood as a fastening element provided for solid-state bonding of at least two or more base materials (not shown) overlapping each other through mechanical bonding methods such as friction and plastic deformation. This is preferable. In addition, the rivet screw drill 200 according to an embodiment of the present invention does not require a separate free hole processing in the base material (not shown), and a fastening element that pierces the base material (not shown) to form a perforation and taps It is preferable to understand

On the other hand, the burring part 110 is connected to the tip part 111 that is rotationally pressed to the base material (not shown) and has a first burring part 112 formed in a rounded outer surface profile, and the first burring part It is preferable to include a second burring part 113 integrally formed on the upper part of the 112 and formed in a discontinuously rounded outer surface profile with the first burring part 112 .

Here, the tip part 111 is formed at the lower end of the burring part 110 to pierce the base material (not shown), and may be formed to be rounded with a radius of curvature of 0.1 to 0.3 mm ^-1 . At this time, it is preferable to understand that the distance a1 between the tip 111 and the virtual center of rotation is formed with the above-mentioned radius of curvature, and the center of rotation of the radius of curvature of the tip 111 is the tip 111 ) may be formed at a position spaced upward by 0.1 to 0.3 mm from the lowermost end to the first burring part 112 side. Of course, in some cases, the tip part 111 may be formed at the lower end of the first burring part 112 in a sharp shape.

And, the tip part 111 and the first burring part 112 so that the perforation of the base material (not shown) pierced by the tip part 111 is expanded according to the rotational pressure of the burring part 110 . The outer surface is formed to be round, but the overall shape may be formed in a shape close to the conical shape.

Accordingly, when the tip part 111 rotationally presses the base material (not shown) at high speed, the perforation is pierced as frictional heat is generated between the tip part 111 and the base material (not shown), and the perforation is the It is friction-cut by the first burring part 112 and may be gradually expanded outward in the radial direction.

In detail, the first burring portion 112 is preferably formed in a shape in which the diameter increases in the circumferential direction from the tip portion 111 to the upper side. At this time, it is preferable that the first burring part 112 is formed to be rounded with a predetermined first radius of curvature toward the upper side. That is, it is preferable that the first burring part 112 is formed to be round in a convex shape with an outer surface profile outward in the radial direction.

In addition, the second burring part 113 is integrally formed on the upper part of the first burring part 112, and the diameter increases with a predetermined second radius of curvature along the circumferential direction toward the upper side and is formed to be round. do.

Here, it is preferable that the outer periphery of the first burring part 112 and the second burring part 113 is formed to be rounded with a preset first radius of curvature and a second radius of curvature, respectively, and the first burring part has a cross-sectional profile. It is formed along a first radius of curvature, and the second burring portion is preferably formed along a second radius of curvature formed larger than the first radius of curvature.

In detail, referring to FIG. 3 , the first radius of curvature of the first burring part 112 is formed to be round to 9.0 to 9.4 mm ^-1 , and the center of rotation of the first radius of curvature is the first burring part 112 . ) may be virtually disposed at a position extending on a horizontal line outward in a radial direction from the uppermost side of the . Here, the distance r1 between the rounded outer surface of the first burring part 112 and the rotation center of the first radius of curvature may be set to 9.0 to 9.4 mm corresponding to the first radius of curvature.

At this time, the rotation center of the first radius of curvature may be virtually disposed at a position extending from the uppermost side of the first burring part 112 on a horizontal line outward in the radial direction, and the shape of the first burring part 112 . Correspondingly, it may be formed to extend in a circular shape surrounding the circumferential direction with respect to the longitudinal central axis of the burring part 110 .

Meanwhile, referring to FIG. 3 , the second radius of curvature of the second burring part 113 is formed to be round to 19.2 to 19.8 mm ^-1 , and the center of rotation of the second radius of curvature is the second burring part 113 . ) may be virtually disposed at a position extending on a horizontal line outward in a radial direction from the uppermost side of the . Here, the interval r2 between the rounded outer surface of the second burring part 112 and the rotation center of the second radius of curvature may be set to 19.2 to 19.8 mm corresponding to the second radius of curvature.

At this time, the rotation center of the second radius of curvature may be virtually disposed at a position extending from the uppermost side of the second burring part 113 on a horizontal line outward in the radial direction, and the shape of the second burring part 113 . Correspondingly, it may be formed to extend in a circular shape surrounding the circumferential direction with respect to the longitudinal central axis of the burring part 110 .

In addition, a ratio between the first radius of curvature of the first burring part 112 and the second radius of curvature of the second burring part 113 may be set to 1:2.11 to 2.13. For example, the first radius of curvature of the first burring part 112 is set to 9.2mm ^-1 , the second radius of curvature of the second burring part 113 is formed to be 19.5mm ^-1 , and the tip ( 111) may be set to a radius of curvature of 0.2 mm ^-1 .

That is, it is preferable to understand that the outer boundary side of the first burring part 112 and the second burring part 113 is discontinuously and clearly separated so that the burring part 110 is formed in a two-stage round structure. And, the boundary side of the first burring part 112 and the second burring part 113 is relatively circumferential compared to the outer surfaces of the first burring part 112 and the second burring part formed in a rounded outer surface profile, respectively. It may be formed in a shape concavely concave inward along the radial direction.

At this time, the minimum outer diameter of the second burring part 113 is the first burring part 112 so that the perforation formed in the base material (not shown) by the tip part 111 and the first burring part 112 is expanded. ) is preferably formed to be greater than or equal to the maximum outer diameter.

In detail, the maximum outer diameter of the first burring portion 112 positioned on the boundary side of the first burring portion 112 and the second burring portion 113 is less than or equal to the minimum outer diameter of the adjacent second burring portion 113 . It is preferably formed by

Accordingly, the tip part 111 and the first burring part 112 are formed to be larger than the outer diameter of the first burring part 112 after the perforation is formed by frictional heat as the base material (not shown) is rotated and pressed. The perforation of the base material (not shown) may be extended radially outward by the second burring part 113 .

In addition, the maximum outer diameter of the first burring portion 113 is preferably formed to substantially correspond to the outer diameter of the tapping portion (120). Through this, the perforation of the base material (not shown) by the first burring portion 113 formed with a maximum outer diameter substantially corresponding to the outer diameter of the tapping portion 120 for forming a tapping screw thread on the inner periphery of the perforation As it is expanded, the forming area of the tapping screw thread is increased, so that the precision of the product can be improved.

In addition, a diameter ratio between the uppermost maximum outer diameter portion of the first burring portion 112 and the uppermost maximum outer diameter portion of the second burring portion 113 may be set to 1:1.41 to 1.43.

For example, when the maximum outer diameter (m2) of the first burring portion 112 and the minimum outer diameter of the second burring portion 113 are set to 3.1mm, the maximum outer diameter of the second burring portion 113 The diameter m1 of the part may be set to 4.4 mm.

In addition, a ratio between each length in the longitudinal direction of the first burring part 112 and the second burring part 113 may be set to 1:1.18 to 1.20. For example, when the longitudinal length k1 of the first burring part 112 is set to 4.2 mm, the longitudinal length k2 of the second burring part 113 may be set to 5.0 mm.

Accordingly, less frictional heat is generated by the first burring part 112 formed to be round with a relatively small outer diameter and a first radius of curvature compared to the tapping part 120, and the base material (not shown) is primarily pierced. can be

Then, the second burring portion ( 113), the perforation of the base material (not shown) may be expanded.

Therefore, with the two-stage piercing structure, frictional heat generated in the initial process of piercing the base material (not shown) is reduced, and as the piercing performance is significantly improved, the manufacturing precision of the tapping screw thread formed in the perforation of the base material (not shown) is improved. can

Furthermore, after the first perforation is pierced at the exact position of the base material (not shown) to be perforated by the tip 111, the perforation is radially outwardly through the burring unit 110 of the two-stage round structure. Since this is expanded, the area and the formation angle of the tapping screw thread formed on the inner periphery of the perforation of the base material (not shown) by the tapping part 120 are uniformly formed, so that a precise tapping screw thread can be manufactured.

Of course, in some cases, the rivet screw drill 200 may be manufactured regardless of each setting ratio between the first burring part 112 and the second burring part 113 described above. Accordingly, it is preferable to understand that the piercing is optimized when the rivet screw drill 200 is manufactured.

Meanwhile, on the outer periphery of the burring part 110 including the first burring part 112 and the second burring part 113 , a boundary between the first burring part 112 and the second burring part 113 . It is preferable that the heat escape groove 114 is formed in the area. Here, the cutting material cut from the base material (not shown) may be temporarily introduced and discharged into the heat escape groove 114 while the burring part 110 pierces the base material (not shown).

Here, it is preferable that the heat escape groove 114 is continuously depressed in the radial direction along the circumferential direction in the boundary region between the first burring part 112 and the second burring part 113 . That is, the heat escape groove 114 is preferably recessed in a ring shape. In addition, it is preferable that the upper end of the first burring portion 112 and the lower end of the second burring portion 113 are spaced apart from each other at a distance corresponding to the vertical width m3 of the heat escape groove 114 . .

In addition, the heat escape groove 114 is recessed to a preset depth along the radial direction of the burring part 110 , and is preferably formed to have a preset width along the vertical direction of the burring part 110 .

In detail, the ratio between the radial depression depth (m4) of the heat escape groove 114 and the diameter (m2) of the maximum outer diameter of the first burring part 112 may be set to 1:15.4 to 15.6. In addition, the ratio between the radial dent depth (m4) of the heat escape groove 114 and the minimum outer diameter of the second burring part 113 may be set to 1:15.4 to 15.6.

For example, when the diameter m2 of the maximum outer diameter of the first burring part 112 is set to 3.1mm, the radial depth m4 of the heat escape groove 114 may be set to 0.2mm.

In addition, a ratio between the vertical width m3 of the heat escape groove 114 and the total length k3 in the longitudinal direction of the burring part 110 may be set to 1:11.1 to 14.3. At this time, it is preferable to understand the overall length of the burring part 110 in the longitudinal direction as the interval between the lower end of the tip part 111 and the upper end of the second burring part 113 .

For example, when the total length k3 in the longitudinal direction of the burring part 110 is set to 10.0 mm, the vertical width m3 of the heat escape groove 114 may be set to 0.8 mm. In this case, the longitudinal length k1 of the first burring part 112 may be set to 4.2 mm, and the longitudinal length k2 of the second burring part 113 may be set to 5.0 mm.

Here, at least one of the radial depression depth m4 of the heat escape groove 114 and the vertical width m3 of the heat escape groove 114 is smaller than the above-mentioned ratio, that is, the heat escape groove ( 114) is formed to be smaller than at least any one of the preset depression depth and the burring part 110 is reduced in the amount of heat generated per hour of frictional heat generated when the base material (not shown) is rotated and pressed by the burring part 110, and the burring part 110 is There is a risk of deformation.

On the other hand, at least one of the radial depth m4 of the heat escape groove 114 and the vertical width m3 of the heat escape groove 114 is greater than the above-mentioned ratio, that is, the heat escape groove ( 114) is formed to be larger than at least any one of the predetermined depression depth and width, there is a fear that the piercing performance of the burring portion 110 is reduced.

Therefore, as the heat escape groove 114 is formed with a predetermined radial depression depth (m4) and a vertical width (m3), the balance between the piercing performance and the heat generation performance of the burring part 110 can be optimized. have.

Accordingly, frictional heat generated while the base material (not shown) is rotationally pressed and pierced by the burring part 110 of the two-stage round structure is generated on the outer periphery of the burring part 110 with the base material (not shown). As the contact area is reduced by the heat escape groove 114 recessed to reduce the deformation due to overheating of the burring part 110 is prevented in advance, durability can be remarkably improved. That is, a clearance space with the base material (not shown) is formed by the heat escape groove 114 continuously formed in the circumferential direction in the boundary region between the first burring part 112 and the second burring part 113 . As it is formed, the contact area is reduced, so that heat generation can be improved.

In addition, since the heat escape groove 114 is formed in a ring shape along the circumferential direction in the boundary region between the first burring part 112 and the second burring part 113, it extends in a straight line along the longitudinal direction or While the piercing performance is improved compared to the prior art in which the escape groove is formed in the form of an oblique line, the heat generation performance can be improved at the same time.

In detail, in the conventional case in which the escape groove is formed in a form extending in a straight line or obliquely along the longitudinal direction, there is a fear that the piercing performance may be deteriorated as the contact surface is reduced when the burring unit rotates and presses the base material. At this time, if the area of the escape groove is reduced in order to increase the contact surface between the burring part and the base material, frictional heat generated during rotational pressing cannot be cooled quickly, so that there is a risk of deterioration of the piercing performance due to the deformation of the burring part.

Accordingly, when the heat escape groove 114 is formed in a ring shape along the circumferential direction in the boundary region between the first burring part 112 and the second burring part 113 as in an embodiment of the present invention, the Less frictional heat is generated by the first burring part 112 formed to be round with a relatively small outer diameter and a first radius of curvature compared to the tapping part 120, and the heat generation after the base material (not shown) is pierced primarily As the burring part 110 is cooled by the escape groove 114 , the perforation of the base material (not shown) may be stably expanded by the second burring part 113 .

That is, as the heat escape groove 114 is located in a boundary region between the first burring part 112 and the second burring part 113 , the first burring part 112 and the second burring part 113 are located. ) and the base material (not shown) while maintaining substantially the formation position of the heat escape groove 114 for frictional heat cooling can be secured.

Accordingly, as the heat escape groove 114 is formed in a ring shape along the circumferential direction in the boundary region between the first burring part 112 and the second burring part 113, the piercing of the burring part 110 is similar. By optimizing the balance between performance and thermal performance, the durability of the product can be significantly improved.

In addition, after the perforation is first pierced in the base material (not shown), the perforation is extended through the burring part 110 having a two-stage round structure between the first burring part 112 and the second burring part 113 . As the heat escape groove 114 in the boundary region is formed in a ring shape along the circumferential direction, the contact area between the first burring part 112 and the second burring part 113 and the base material (not shown) compared to the related art. This can be substantially increased to improve the fastening strength and durability.

At the same time, the heat escape groove 114 for frictional heat cooling is formed in the boundary region between the first burring part 112 and the second burring part 113 along the circumferential direction, and the burr caused by overheating in the piercing process. Since deformation of the ring part 110 is prevented, piercing performance and durability may be remarkably improved.

On the other hand, the tapping part 120 is integrally connected to the upper part of the burring part 110, and a thread 121 for tapping the inner periphery of the perforation formed in the base material (not shown) is preferably formed on the outer surface.

In addition, the longitudinal length ratio of the burring part 110 and the tapping part 120, that is, the total length k3 in the longitudinal direction of the burring part 110 and the total length in the longitudinal direction of the tapping part 120 ( The ratio between k7) may be set to 1:1.16 to 1.18. For example, when the total length k3 in the longitudinal direction of the burring part 110 is set to 10.0 mm, the total length k7 in the longitudinal direction of the tapping part 120 may be set to 11.7 mm.

Here, as the total length k3 in the longitudinal direction of the burring part 110 is longer, the heating rate of frictional heat generated in the process of the burring part 110 piercing the base material (not shown) of the same thickness can be improved. . In addition, the total length k7 in the longitudinal direction of the tapping part 120 may be required to have a length greater than or equal to a preset length in order to form a tapping thread on at least two or more of the base materials (not shown) of a preset thickness.

At this time, as the ratio between the total length k3 in the longitudinal direction of the burring part 110 and the total length k7 in the longitudinal direction of the tapping part 120 is set to 1:1.16 to 1.18, the rate of heat generation and the formation of the tapping screw thread It can be formed in an optimized ratio to provide different functions.

And, it is preferable that the longitudinal width of the first screw thread 121a formed at the lower part of the thread 121 of the tapping part 120 is larger than the longitudinal width of the second screw thread 121b formed at the upper part of the tapping part. .

Here, the screw thread 121 may be formed to be continuously wound along the outer surface of the tapping part 120 , and the longitudinal width of the screw thread 121 decreases toward the upper part of the tapping part 120 . and the spacing between the respective threads 121 may be reduced.

In detail, the second screw thread 121b is between the burring part 110 and the head part 130 so as to be screw-fastened substantially to the perforated inner periphery of the base material (not shown) punched by the burring part 110 . It is preferably formed on the outer periphery of the formed tapping part 120 .

In addition, the first screw thread 121a supports the perforation before the second screw thread 121b is screw-fastened to the inner periphery of the perforation of the base material (not shown) perforated by the burring part 110 to provide a supporting force. It is preferable to be formed on the outer periphery of the tamping part 120 between the second screw thread 121b and the burring part 110 .

Here, the first screw thread 121a has relatively fewer threads than the threads of the second screw thread 121b, and the tooth cross-sectional area of the first screw thread 121a thread is greater than that of the second screw thread 121b. can be formed large.

In addition, the second screw thread 121b may be formed of threads having a triangular cross-sectional shape, and the first screw thread 121a may be formed of threads having a rounder cross-sectional shape that is smoother than that of the second screw thread 121b. .

Here, the first screw thread 121a of the tapping part 120 after the burring part 110 rotates and presses the base material (not shown) to pierce the base material (not shown) through a pressing force and a rotational force applied from a bonding tool (not shown), which will be described later. ) is rotationally pressed along the perforation inner periphery of the base material (not shown) and may be supported by the perforation rim. Then, as the second screw thread 121b of the screw thread 121 is inserted into the perforation of the base material (not shown), a tapping screw thread may be formed on the inner periphery of the perforation.

Accordingly, since the first screw thread 121a is supported by the perforation before the second screw thread 121b of the tapping part 120 is screwed onto the inner periphery of the perforation of the base material (not shown), the rivet screw drill 200 ) maintains a substantially right angle with respect to the base material (not shown) and joins the base material (not shown), so work convenience and manufacturing precision can be improved.

On the other hand, the head part 130 is integrally connected to the upper portion of the tapping portion 120, is formed to extend outwardly in the radial direction of the tapping portion 120, and a bonding tool (not shown) for reciprocating and rotating on the upper portion. ) is optionally mounted.

Here, the bonding tool (not shown) is preferably understood as a separately provided device for rotationally pressing the rivet screw drill 200 . In this case, the bonding tool (not shown) may be provided to guide the rivet screw drill 200 , and may be provided to simultaneously move and rotate the rivet screw drill 200 in the vertical direction. That is, the bonding tool (not shown) may be rotatably provided while reciprocating in a linear direction by a predetermined driving means. For example, the bonding tool (not shown) may include a mount part for clamping the head part 130 and a driving part (not shown) capable of rotating the mount part while reciprocally moving the mount part up and down.

In addition, the head unit 130 includes a mounting protrusion 131 coupled to the bonding tool (not shown), and a seating step 132 formed between the mounting protrusion 131 and the tapping unit 120 . It is preferable to include

In addition, it is preferable that the seating step 132 is extended radially outward along the circumferential direction between the mounting protrusion 131 and the tapping part 120 . Here, the seating step 132 may provide a function of being seated on and supporting the base material (not shown) after the burring part 110 and the tapping part 120 pass through the base material (not shown). have.

In addition, the head portion 130 has a mounting protrusion 131 coupled to the bonding tool (not shown) that protrudes upward, and the mounting protrusion 131 has a plurality of protrusion-type fittings that protrude radially along the circumferential direction ( 131a) is preferably formed. At this time, it is preferable to understand that the mounting protrusion 131 and the protruding tongue type fitting portion 131a are integrally formed.

Here, the mounting protrusion 131 is formed to protrude from the center of the upper surface of the head unit 130, and the protrusion-shaped fitting portion 131a extends radially from the mounting protrusion 131 in a plurality of places in the circumferential direction. desirable. In this case, it is preferable that the mounting protrusion 131 and the protruding tongue-type fitting portion 131a are formed to correspond to the shape of the mounting groove so as to be fitted into the mounting groove of the bonding tool (not shown).

For example, the protrusion-shaped fitting portion 131a may be formed in a petal shape, a pinwheel shape, or the like by protruding six places radially outward from the mounting protrusion 131 . At this time, it is preferable that a space formed concavely in the radial direction is formed between each of the protruding tongue-shaped fitting portions 131a, respectively. That is, the side profile of the protrusion-shaped fitting portion 131a may be formed to be rounded or curved.

Accordingly, the mounting protrusion 131 is clamped and fixed in the mounting groove provided in the mounting part of the bonding tool (not shown), and the rivet screw drill 200 is performed by the bonding tool (not shown). The base material (not shown) may be tapped by rotationally pressing.

In addition, the upper outer rim of the mounting protrusion 131 is bent in the form of a flat surface inclined to increase the contact area with the joining tool (not shown) between each of the protrusion-shaped fitting portions 131a along the circumferential direction. It is preferable that the plurality of contact inclined surfaces 134 are alternately formed at a predetermined distance from each other.

Through this, the contact area is increased as the bonding tool (not shown) is seated on each of the contact inclined surfaces 134 and is engaged with the surface contact, so that the torque transmission force can be remarkably improved.

Meanwhile, in the head part 130 , a seating step 132 between the mounting protrusion 131 coupled to the bonding tool (not shown) and the tapping part 120 extends radially outward along the circumferential direction. It is preferable to form

In addition, it is preferable that the hardening guide groove 133 from the inner end of the seating step 132 in the head part 130 surrounds the upper outer surface of the tapping part 120 and is depressed continuously upward along the circumferential direction. .

In addition, the rivet screw drill 200 is provided in a ring shape having an inner diameter corresponding to the outer diameter of the tapping part 120 to be interposed in the hardening guide groove 133 , and the upper part is fitted to the hardening guide groove 133 , The lower portion may further include a molten coating portion 140 disposed exposed to the lower side of the curing guide groove (133).

Here, the melt coating part 140 may be provided as a solidified epoxy ring, and the rivet screw drill 200 is first melted and deformed by the friction force generated when the rivet screw drill 200 is rotated and pressed against the base material (not shown). have.

And, the melt coating part 140 is molded and fixed to the hardening guide groove 133 as the first melted upper part is secondarily hardened, and the first melted lower part is rotated in the rivet screw drill 200 . It extends outward in the radial direction along the circumferential direction and may be closely coupled between the lower surface of the seating step 132 and the base material (not shown).

Through this, the upper part of the molten-coated part 140 is melted by the rotational friction force in the hardening guide groove 133 which is recessed upward along the circumferential direction from the inner end of the seating step 132, then hardened and formed, and the lower part is formed. Since it is closely coupled between the lower surface of the seating step 132 and the base material (not shown), galvanic corrosion is minimized and durability can be remarkably improved.

Here, the hardening guide groove 133 is preferably formed to be inclined downward toward the radial direction outward along the circumferential direction. In addition, the upper surface contour of the molten coating portion 140 is preferably formed to correspond to the contour of the curing guide groove (133).

In addition, the distance f1 between the upper end and the lower end of the melt-coated portion 140 may be set to exceed the distance f2 between the lower end of the seating step 132 at the upper end of the curing guide groove 133 .

Here, when the distance f1 between the upper end and the lower end of the molten coating part 140 is set to be less than the distance f2 between the upper end of the hardening guide groove 133 and the lower end of the seating step 132, the rivet The lower portion of the molten coating portion 140, which is first melted by the rotational friction heat of the screw drill 200, is expanded radially outward along the circumferential direction by the rotation of the rivet screw drill 200, and the seating step 132 There is a fear that it may not be closely coupled between the lower surface and the base material (not shown).

Accordingly, as the distance f1 between the upper end and the lower end of the melt-coated portion 140 is set to exceed the distance f2 between the lower end of the seating step 132 at the upper end of the curing guide groove 133, the melting The lower portion of the coating unit 140 may be stably and closely coupled between the lower surface of the seating step 132 and the base material (not shown).

In addition, the distance f2 between the lower end of the seating step 132 at the upper end of the hardening guide groove 133 is the distance f3 between the lower end of the molten coating part 140 at the lower end of the seating step 132 . It can be set to more than

Here, the distance f2 between the lower end of the seating step 132 from the upper end of the hardening guide groove 133 is less than the distance f3 between the lower end of the molten coating part 140 from the lower end of the seating step 132 When set to , the lower portion of the molten coating portion 140 that is first melted by the frictional heat of rotation of the rivet screw drill 200 is radially outward along the circumferential direction by the rotation of the rivet screw drill 200 . During expansion, the support force of the upper portion of the melt-coated portion 140 is lost, and there is a risk that the melt-coated portion 140 may be separated from the curing guide groove 133 . That is, there is a risk that the whole of the melt-coated portion 140 in the process of being deformed by the rotational force of the rivet screw drill 200 in the lower portion of the molten-coated portion 140 radially outwardly.

Therefore, the distance f2 between the lower end of the seating step 132 from the upper end of the hardening guide groove 133 is greater than the gap f3 between the lower end of the molten coating part 140 from the lower end of the seating step 132 . As set to , the upper part is stably supported inside the hardening guide groove 133 during thermal deformation of the lower part of the melt coating part 140 and, after hardening, is stably molded and fixed in the hardening guide groove 133. Delamination can be minimized.

Meanwhile, a friction reducing coating made of zinc nickel (Zn-Ni) material may be continuously coated on the surfaces of the burring part 110 , the tapping part 120 , and the head part 130 . At this time, the coefficient of friction of the zinc-nickel material is 0.18, which is lower than that of the conventional aluminum plating of 0.47.

Through this, the surface of the burring part 110, the tapping part 120, and the head part 130 is continuously coated with the friction reducing coating part made of zinc-nickel (Zn-Ni) material. Piercing performance can be improved as frictional heat is reduced.

In this case, terms such as "comprises", "comprises" or "include" described above mean that the corresponding component may be inherent unless otherwise stated, so other components are excluded. Rather, it should be construed as being able to include other components further. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention belongs, unless otherwise defined. Terms commonly used, such as those defined in the dictionary, should be interpreted as being consistent with the contextual meaning of the related art, and are not interpreted in an ideal or excessively formal meaning unless explicitly defined in the present invention.

As described above, the present invention is not limited to each of the above-described embodiments, and modifications can be implemented by those of ordinary skill in the art to which the present invention pertains without departing from the scope of the claims of the present invention. and such modifications are within the scope of the present invention.

200: rivet screw drill 110: burring part
111: tip 112: first burring part
113: second burring part 114: heat escape groove
120: tapping part 121: thread
130: head 131: mounting projection
132: seating step 133: hardening guide groove
134: contact inclined surface 140: melt hardening part

Claims (15)

A rivet screw drill for piercing and tapping a base material, comprising:
A first burring part connected to the tip part which is rotationally pressed to the base material and formed with a rounded outer surface profile in cross section, and integrally formed on the upper part of the first burring part, the cross section is discontinuously rounded with the first burring part a burring portion including a second burring portion formed in an outer profile, wherein a heat escape groove is formed in a boundary region between the first burring portion and the second burring portion;
a tapping part integrally connected to the upper part of the burring part and having a thread for tapping the inner periphery of the perforation formed in the base material on the outer surface; and
A rivet screw drill comprising a head integrally connected to an upper portion of the tapping portion, extending outward in a radial direction of the tapping portion, and selectively mounting a joint tool for reciprocating movement and rotation on the upper portion. The method of claim 1,
The heat escape groove is a rivet screw drill, characterized in that in the boundary region between the first burring portion and the second burring portion is continuously depressed in the radial direction along the circumferential direction. 3. The method of claim 2,
The heat escape groove is recessed to a predetermined depth along the radial direction, and is formed to have a predetermined width along the vertical direction,
The ratio between the radial depression depth of the heat escape groove and the diameter of the maximum outer diameter of the first burring part is set to 1:15.4 to 15.6,
Rivet screw drill, characterized in that the ratio between the vertical width of the heat escape groove and the total length of the burring part in the longitudinal direction is set to 1:11.1 to 14.3. 3. The method of claim 2,
The cross-sectional profile of the first burring part is formed along a first radius of curvature,
The second burring part is a rivet screw drill, characterized in that formed along a second radius of curvature formed larger than the first radius of curvature. 5. The method of claim 4,
The rotation center of the first radius of curvature is disposed at a position extending from the uppermost side of the first burring part in a radial direction outward on a horizontal line,
The center of rotation of the second radius of curvature is a rivet screw drill, characterized in that it is disposed at a position extending from the uppermost side of the second burring part radially outward on a horizontal line. 6. The method of claim 5,
The first burring part and the second burring part are formed to be rounded with a predetermined first and second radius of curvature toward the upper side, respectively, and the maximum outer diameter of the first burring part is formed to be less than or equal to the minimum outer diameter of the second burring part become,
Rivet screw drill, characterized in that the ratio between the first radius of curvature of the first burring portion and the second radius of curvature of the second burring portion is set to 1:2.11 to 2.13. 7. The method of claim 6,
A rivet screw drill, characterized in that the diameter ratio between the maximum outer diameter of the first burring portion and the maximum outer diameter of the second burring portion is set to 1:1.41 to 1.43. 7. The method of claim 6,
A rivet screw drill, characterized in that the first burring portion and the second burring portion length ratio in the longitudinal direction is set to 1:1.18 to 1.20. 7. The method of claim 6,
Rivet screw drill, characterized in that the ratio of the longitudinal length of the burring portion and the tapping portion is set to 1:1.16 to 1.18. The method of claim 1,
A seating step is formed in the head part to extend radially outward along the circumferential direction between the mounting protrusion coupled to the joining tool and the tapping part,
A hardening guide groove is formed in the head part from the inner end of the seating step, which surrounds the upper outer surface of the tapping part and is continuously depressed upward along the circumferential direction,
The rivet screw drill further comprising a molten coating part interposed in a ring shape having an inner diameter corresponding to the outer diameter of the tapping part, wherein the upper part is fitted to the hardening guide groove and the lower part is exposed to the lower side of the hardening guide groove. 11. The method of claim 10,
The distance between the upper end and the lower end of the molten coating part is set to exceed the distance between the lower end of the seating step at the upper end of the curing guide groove,
A rivet screw drill, characterized in that the interval between the upper end of the hardening guide groove and the lower end of the seating step is set to be greater than or equal to the distance between the lower end of the molten coating part from the lower end of the seating step. The method of claim 1,
A mounting protrusion coupled to the bonding tool protrudes upwardly from the head portion,
A rivet screw drill, characterized in that the mounting protrusion is formed with a plurality of protruding protrusions radially protruding along the circumferential direction. 13. The method of claim 12,
A rivet screw drill, characterized in that on the upper outer edge of the mounting protrusion, a plurality of contact inclined surfaces bent in the form of a flat surface inclined between each of the protruding tongue-shaped mating portions along the circumferential direction are alternately formed at a predetermined distance from each other. The method of claim 1,
A rivet screw drill, characterized in that the surface of the burring part, the tapping part, and the head part is continuously coated with a zinc-nickel friction reducing coating. A rivet screw drill for piercing and tapping a base material, comprising:
A first burring part connected to the tip that is rotationally pressed to the base material and formed in a rounded outer surface profile along a first radius of curvature having a center of rotation having a cross-section disposed at a position extending in a horizontal direction from the uppermost side to the outside in the radial direction And, is integrally formed on the upper part of the first burring part and the cross section is formed of a discontinuously rounded outer surface profile with the first burring part, which is larger than the first radius of curvature and extends radially outward from the uppermost side on a horizontal line A burring portion comprising a second burring portion formed along a second radius of curvature having a rotation center disposed at a position, wherein a heat escape groove is formed in a circumferential direction in a boundary region between the first burring portion and the second burring portion ;
a tapping part integrally connected to the upper part of the burring part, the tapping part having a thread for tapping the inner periphery of the perforation formed in the base material on the outer surface; and
A rivet screw drill comprising a head integrally connected to the upper portion of the tapping portion, extending outward in the radial direction of the tapping portion, and selectively mounting a joint tool for reciprocating movement and rotation on the upper portion.

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