WO2017159896A1

WO2017159896A1 - Tapping screw capable of minimizing material strain rate of object to be coupled

Info

Publication number: WO2017159896A1
Application number: PCT/KR2016/002733
Authority: WO
Inventors: 이성윤
Original assignee: 주식회사 서울금속
Priority date: 2016-03-17
Filing date: 2016-03-17
Publication date: 2017-09-21

Abstract

The present invention relates to a tapping screw capable of minimizing the rate and area of material strain in an object to be coupled when the tapping screw is screwed thereinto. Specifically, the present invention comprises: a head part; and a body part connected at one end to the head part and provided with a plurality of screw threads on the outer circumferential surface, wherein the screw threads are provided with a structure for lessening the resistance to material movement on the full surface of the flanks, the structure reducing the resistance of the material of the object to be coupled for moving along the surfaces of the flanks and outer circumferential surface of the body part of the tapping screw when the screw threads are screwed into the object to be coupled.

Description

Tapping screw to minimize material strain of fastening object

The present invention relates to a tapping screw, and more particularly, to a tapping screw that can minimize the material strain and the material deformation portion of the fastening object when fastened to the fastening object.

In general, screws (screws) generally have a strong fixing force when joining a plurality of components, including mechanical parts or electronics, easy construction, and can adjust the fastening force according to the fastening partner (or the base material). Use screws that are easy to disassemble at the same time.

Such screws are divided into triangular screws, square screws, trapezoidal screws, toothed screws, round screws, ball screws, etc., depending on the cross-sectional shape of the thread formed on the outer circumferential surface. It is divided into various head screws.

In addition, according to the shape of the screw is divided into a variety of small screws, stop screws, screws, tapping screws, heli-inserts.

At this time, the tapping screw (Tapping screw) is a screw that can be clipped to form a female screw on the fastening object by the screw itself.

When fastening to the fastening object using such a tapping screw, the material flows along the flank of the tapping screw while the fastening object is partially melted due to frictional heat between the flank of the tapping screw and the fastening object. In the case of screws, since the flank is composed of a single inclined surface, there has been a problem in that the material flow resistance is large because the flow path changes rapidly from the flank to the outer peripheral surface of the body.

The large material flow resistance generated in this way has increased the frictional heat of the fastening object to increase the material strain and the material deformation portion of the fastening object. As the material strain and the material deformation portion are increased, there has been a problem that the fastening force of the tapping screw on the fastening object is reduced, and the defective rate of the fastening object is increased.

Therefore, the present applicant, the present invention has been proposed in order to solve the above problems, as related prior art documents, Republic of Korea Utility Model Publication No. 20-0478117 (name of the invention: screw fastening to wood easy to screw , Registration date: 2015.08.24).

It is an object of the present invention to provide a tapping screw that solves the conventional problems.

Specifically, it is an object of the present invention to provide a tapping screw that can minimize the material strain and the material deformation portion of the fastening object when fastened to the fastening object.

The problem to be solved by the present invention is not limited to the above-mentioned problem, another task that is not mentioned will be clearly understood by those skilled in the art from the following description.

According to an embodiment of the present invention for solving the above problems, the present invention, the head; And a body part having one end connected to the head and having a plurality of fastening threads provided on an outer circumferential surface thereof, wherein the fastening thread includes a flank of the fastening thread and the body when the fastening thread is fastened to a fastening object. A tapping screw can be provided, comprising a material flow resistance alleviation structure for reducing the material flow resistance of the fastening object along the outer circumferential surface of the entire portion of the flank.

Further, preferably, the fastening screw thread is configured such that a flank angle, which is an angle between opposing flank surfaces, increases from the peak portion of the fastening screw thread to the valley portion.

Preferably, the fastening screw thread may include: a first flank portion positioned at a peak portion of the fastening screw thread, the flank angle being an angle between opposing flank surfaces being a first flank angle preset; A second flank portion extending below the first flank portion and having a predetermined second flank angle greater than the predetermined first flank angle; And a third flank portion extending between a lower portion of the second flank portion and an outer circumferential surface of the body portion and having a predetermined third flank angle greater than the predetermined second flank angle.

Further, preferably, the predetermined first flank angle and the predetermined second flank angle are within an angle range of 20 ° to 50 °.

Further, preferably, the predetermined first flank angle is in an angular range of 15 ° to 25 °, and the predetermined second flank angle is in an angular range of 35 ° to 45 °, and the predetermined third flank The angle is characterized in that it is in the angle range of 55 ° to 65 °.

Preferably, the fastening screw thread is configured such that the height of the first flank portion: the height of the second flank portion: the height of the third flank portion is 1: 1: 0.5 to 1.

Also preferably, the fastening screw thread is configured such that the height of the first flank portion is 0.25 to 0.5 times the sum of the height of the second flank portion and the height of the third flank portion.

Preferably, the fastening screw thread is characterized in that the pitch of the plurality of fastening screw threads is configured to be 0.15 to 0.5 times the outermost outer diameter of the fastening screw thread.

According to the above solution, the present invention can minimize the material strain and the material deformation portion of the fastening object when the tapping screw is fastened to the fastening object. Therefore, the present invention increases the fastening area of the tapping screw for the fastening object by minimizing the material strain and the material deformation portion, thereby improving the fastening force and having an effect of significantly reducing the defective rate of the fastening object itself.

In addition, the present invention can easily form a female thread on the fastening object by having a first flank, thereby improving the convenience of fastening, and at the same time, by providing a second flank and / or a third flank, the mechanical strength of the screw thread can be stably maintained. It can be secured.

1 is a schematic perspective view of a tapping screw according to an embodiment of the present invention.

FIG. 2 is a schematic enlarged view of the tapping screw of FIG. 1. FIG.

3 is a schematic cross-sectional view of FIG. 2.

4 is a schematic partial enlarged cross-sectional view of a tapping screw according to the first prior art showing the material flow of the fastening object.

5 is a schematic partially enlarged cross-sectional view of a tapping screw according to the second prior art showing the material flow of the fastening object.

6 is a schematic diagram of a tapping screw according to an embodiment of the present invention showing the material flow of the fastening object.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

It is noted that the figures are schematic and not drawn to scale. The relative dimensions and ratios of the parts in the figures have been exaggerated or reduced in size for clarity and convenience in the figures and any dimensions are merely exemplary and not limiting. And the same reference numerals are used to refer to similar features in the same structure, element or part shown in more than one figure.

Embodiments of the present invention specifically illustrate ideal embodiments of the present invention. As a result, various modifications of the drawings are expected. Thus, the embodiment is not limited to the specific form of the illustrated region, but includes, for example, modification of the form by manufacture.

Hereinafter, a tapping screw 100 (hereinafter referred to as 'tapping screw') according to an embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a schematic perspective view of a tapping screw 100 according to an embodiment of the present invention, FIG. 2 is a schematic enlarged view of the tapping screw 100 of FIG. 1, and FIG. 3 is a schematic view of FIG. 2. 4 is a schematic partial enlarged cross-sectional view of the tapping screw 100 according to the first conventional art showing the material flow Fm of the fastening object O, and FIG. 5 is a material flow (of the fastening object O) FIG. 6 is a partially enlarged cross-sectional view of a tapping screw 100 according to the second prior art representing Fm), and FIG. 6 is a tapping screw according to an embodiment of the present invention showing a material flow Fm of the fastening object O. 100 is a schematic diagram.

As shown in Figures 1 to 3, the tapping screw 100 according to an embodiment of the present invention, is connected to the head 110 and the head 110 and a plurality of fastening threads 130 on the outer peripheral surface It may include a body portion 120 is provided.

1 to 3, the head 110 is a portion connected to the body 120. One end of the head 110 may be connected to the body portion 120, the other end may be a fastening portion (not shown). Here, the fastening part (not shown) formed at the other end of the head 110 is a tool for fastening the tapping screw 100 to the fastening object (O) or the preformed bore (B) of the fastening object (O). As a part that can be fitted, it is preferred that the tool be provided in the form of a groove or groove so that the tool can be inserted. In addition, when the body 120 is completely inserted into the fastening object O by a tool inserted into the fastening part (not shown) of the head 110, one end of the head 110 is fastened to the fastening object O. Can be fully contacted.

Meanwhile, although the shape of the head 110 is illustrated in the form of a cylinder in the drawing, the shape of the head 110 is not necessarily limited thereto, and may be formed in various shapes such as a rectangle and a hexagon.

In addition, one end of the body 120 may be connected to the head 110, and a plurality of fastening threads 130 may be provided on an outer circumferential surface of the body 120. Specifically, the body portion 120 may be formed in a cylindrical shape having a length narrower than the width of the head 110 and the longitudinal direction. In this case, a plurality of fastening threads 130 may be provided on the outer circumferential surface of the body 120 having a cylindrical shape.

In addition, the fastening thread 130 provided in the body portion 120 and the body portion 120 is provided with a plurality of fastening screw 130 is a fastening object (O) or in advance of the fastening object (O) along the fastening direction. Enter the formed bore (B) to form a female thread. Here, the fastening direction (see F in FIG. 2) means one end of the body portion 120 from the other end of the body portion 120 (that is, the opposite end of the portion in which the head portion 110 is provided). Means the direction toward the head 110 is provided).

That is, the tapping screw may be fastened to the fastening object O through a female thread formed in the fastening object O by the flank of the fastening screw 130 and the fastening screw thread.

As shown in the figure, the fastening screw 130 is preferably a cross-sectional shape of the flank surface is formed in a straight line.

Specifically, the fastening thread 130 is a first flank surface and a flank surface facing the other end side of the body portion 120 (ie, the fastening direction) and one end side of the body portion 120. A second flank surface which is a flank surface facing (ie facing in the opposite direction to the fastening direction F2) and a flank angle formed by the first and second flank surfaces (ie, opposite flank surfaces). Angle), a first flank side angle formed by the axis or axis direction of the first flank and the body portion, and an axis or axis direction A of the second flank surface and the body portion 120 are formed. Second flank lateral angle. Here, the flank angle again includes a front flank angle and a rear flank angle. The front flank angle means an angle formed by a vertical line with respect to the axis of the first flank surface and the body portion, and the rear flank angle means an angle formed by a vertical line with respect to the axis line of the second flank surface and the body portion.

According to this embodiment, the fastening screw 130 is configured to extend in the upper direction from the outer peripheral surface of the body portion 120, the fastening screw 130 is a material flow over the entire flank surface of the fastening screw 130 It has a resistance alleviation structure. The material flow resistance relief structure of the fastening object 130 along the flank surface of the fastening screw 130 and the outer peripheral surface of the body portion 120 when the fastening screw 130 is fastened to the fastening object (O) It means the shape of the flank surface to reduce the material flow resistance.

The material flow resistance relief structure is configured such that the flank angle in the fastening screw thread 130 increases from the peak portion of the fastening screw thread 130 to the bone portion. That is, the material flow resistance mitigation structure gradually gradually angles the angle between the flank surface, which is the path of movement of the material flow Fm formed by the frictional heat between the tapping screw and the fastening object O, and the outer circumferential surface of the body portion 120. It can be formed so as to prevent the material flow (Fm) path to change suddenly or at a sharp angle.

Specifically, as shown in FIGS. 2 and 3, the fastening screw 130 has a first bottom flank that extends integrally with the first flank 131 at the top and the outer circumferential surface of the body 120. And a third flank 133 and a second flank 132 connecting the first flank 131 and the third flank 133.

As shown in FIGS. 2 and 3, the first flank 131 is located at a peak of the fastening screw thread 130 and has a first flank angle of which a flank angle, which is an angle between opposing flanks, is a predetermined angle. θ1) is the uppermost part. Here, the fastening thread 130 may be a symmetrical thread in which the first first flank angle θ1 is the same as the first front flank angle and the first rear flank angle.

Preferably, the preset first flank angle θ1 is within an angle range of 15 ° to 25 °, and more preferably, the preset first flank angle θ1 is 20 °.

When the predetermined first flank angle θ1 is less than 15 °, the thickness of the first flank 131 becomes too thin, so that the mechanical strength of the first flank 131 on which the fastening stress and the fastening torque are concentrated is excessively increased. This is because there is a high possibility that the first flank 131 breaks when tightened. In addition, when the predetermined first flank angle θ1 is greater than 25 °, the thickness of the first flank 131 becomes too thick, so that the tightening torque is large due to the thickness of the first flank 131 and the friction surface area. This is because there is a disadvantage that the fastening of the tapping screw is not easy. That is, by forming the predetermined flank angle within the angle range of 15 ° to 25 °, it is possible to prevent the breakage of the first flank 131 and at the same time to achieve a sharp shape to improve the ease of fastening.

The second flank 132 extends below the first flank 131 and is configured to have a second flank angle θ2 greater than the first flank angle θ1.

Preferably, the preset second flank angle θ2 is within an angle range of 35 ° to 45 °, and more preferably, the preset second flank angle θ2 is 40 °.

When the preset second flank angle θ2 is less than 35 °, the preset second flank angle θ2 of the second flank 132 and the preset first flank angle of the first flank 131 may be used. This is because the angle difference of θ1 is almost eliminated so that the material flow (Fm) resistance relaxation function is not only deteriorated, but also the mechanical strength reinforcement function of the fastening thread 130, which is the main function of the second flank 132, is greatly reduced. In addition, when the preset second flank angle θ2 is greater than 45 °, the preset second flank angle θ2 of the second flank 132 and the preset first flank of the first flank 131. This is because the angular difference between the angles θ1 becomes excessively large, which lowers the material flow (Fm) resistance mitigation function.

Preferably, the predetermined first flank angle θ1 and the predetermined second flank angle θ2 may be within an angle range of 20 ° to 50 °. For this reason, the screw fastening torque of a tapping screw can be reduced and fastening easiness can be improved.

The third flank 133 extends between a lower portion of the second flank 132 and an outer circumferential surface of the body 120 and has a preset second greater than the predetermined second flank angle θ2. It is comprised so that it may have three flank angles (theta) 3.

The predetermined third flank angle θ3 is preferably within an angle range of 55 ° to 65 °, and more preferably, the predetermined third flank angle θ3 is 60 °.

This means that when the preset third flank angle θ3 is less than 55 °, the preset third flank angle θ3 of the third flank 133 and the second preset flank angle of the second flank 132 are set. The angle difference of θ2 is almost eliminated and at the same time, the angle between the flank of the third flank 133 and the outer circumferential surface of the body part 120 (ie, flank side angle) is excessively increased, thereby alleviating material flow (Fm) resistance. This is because not only the function is significantly reduced, but also the mechanical strength reinforcement function of the fastening screw 130, which is the main function of the third flank 133, is greatly reduced. In addition, when the preset third flank angle θ3 is greater than 65 °, the preset third flank angle θ3 of the third flank 133 and the second preset flank of the second flank 132 are set. This is because the angular difference between the angles θ2 becomes excessively large, which lowers the material flow (Fm) resistance mitigation function.

As a further embodiment, the fastening threads 130 may be asymmetric threads. In this case, the first flank angle θ1 of the fastening screw 130 is formed to be different from the first front flank angle and the first rear flank angle, and / or the second flank angle of the fastening screw 130 ( θ2) is different from the second front flank angle and the second rear flank angle, and / or the third flank angle θ3 of the fastening thread 130 is different from the third front flank angle and the third rear flank angle. Is formed. In the following, in order to avoid duplication of description, the description will be made based on the first flank angle θ1.

First, the asymmetric thread may be formed to have a slope of the second flank surface is gentler than that of the first flank surface, so that the size of the first front flank angle may be smaller than the first rear flank angle. . The asymmetric thread provided as described above is inclined in the same direction as the fastening direction F of the tapping screw 100, and since the asymmetric thread is inclined toward the advancing direction of the tapping screw, the first flank and the fastening object ( The stress generated between O) can be concentrated to increase the effect of preventing loosening of the tapping screw 100.

On the contrary, the asymmetrical thread may have a gentler slope of the first flank than the slope of the second flank. Accordingly, the size of the first front flank angle of the asymmetric thread may be larger than the first rear flank angle. Since the asymmetric thread is inclined toward the opposite direction of the fastening direction of the tapping screw 100, the stress generated between the second flank surface and the fastening object O is concentrated to increase the effect of preventing loosening of the tapping screw. Can be.

Meanwhile, the inclinations of the first and second flanks of the asymmetric thread are not limited thereto, and the inclination of the first and second flanks (ie, the first front flank angle) depends on the position at which the asymmetric threads are provided. And the first rear flank angle) may vary.

Preferably, the fastening screw 130, the height h1 of the first flank 131: the height h2 of the second flank 132: the height of the third flank 133 (h3) may be configured to be 1: 1: 0.5 to 1.

In addition, preferably, the fastening screw 130 has a height h1 of the first flank 131 and a height h2 of the second flank 132 and the third flank 133. It can be configured to be 0.25 to 0.5 times the sum of the height (h3) of.

When the height of the first flank 131 is less than 0.25 times the sum of the height of the second flank 132 and the height of the third flank 133, the sharp portion of the entire fastening screw 130 may be reduced. It is because it reduces too much and the ease of fastening falls remarkably. In addition, when the height of the first flank 131 is greater than 0.5 times the sum of the height of the second flank 132 and the height of the third flank 133, the overall thickness of the fastening screw 130 is The thin portion (i.e., the first flank 131) is too large and at the same time, the portion (i.e., the second flank 132 and / or the third flank 133) is too small to be fastened. This is because the mechanical strength of the first flank 131 where the stress and the fastening torque are concentrated is excessively weakened so that the first flank 131 may be broken during fastening.

In addition, preferably, the fastening screw 130 may be configured such that the pitch P of the plurality of fastening threads 130 is 0.15 to 0.5 times the outermost outer diameter of the fastening screw 130. As a result, while the fastening screw 130 is fastened to the fastening object O, the material flow (Fm) space of the fastening object O may be secured due to frictional heat, thereby efficiently forming a female thread on the fastening object O. It is possible to secure the fastening area at the same time as it can secure the fastening force with high reliability.

Hereinafter, the operation and effect of the present invention will be described in more detail with reference to FIGS. 4 to 6 as compared with the prior art.

As shown in FIG. 4, the tapping screw according to the first prior art is based on both sides of the bottom part of the third flank 133 of the present invention and both sides of the top part of the first flank 131 of the present invention. It has a screw thread 10 set to.

Referring to Figure 4, the flank side angle of the tapping screw according to the first prior art is made at a significantly larger angle than the present invention, whereby the material flow (Fm) path of the fastening object (O) of the first prior art Since the flank surface and the outer peripheral surface of the body portion 120 changes rapidly, the material flow (Fm) stagnation and concentration and accumulation in the outer peripheral surface of the body portion 120 as well as the body portion 120 due to the accumulated material flow Repulsive flow (Fr) is formed on the outer circumferential surface of the, the friction heat between the first surface of the flank and the outer circumferential surface of the body portion 120 of the prior art is largely generated and the material strain is large and the material deformation section (D) is formed large Able to know.

As shown in FIG. 5, the tapping screw according to the second prior art includes a thread 20 set based on a first first flank angle θ1 of the first flank 131 of the present invention.

Referring to FIG. 5, the flank side angle of the tapping screw according to the second prior art is made at a significantly larger angle than that of the present invention (and also compared to the first prior art), and thus the material flow of the fastening object O ( Since the Fm) path changes abruptly at the flanks of the second prior art and the outer circumferential surface of the body portion 120, the material flow Fm is stagnated, concentrated and accumulated at the outer circumferential surface of the body portion 120 as well as accumulated Due to the flow of the repulsive flow (Fr) is formed on the outer peripheral surface of the body portion 120, due to this the frictional heat is generated largely between the flank surface of the second prior art and the outer peripheral surface of the body portion 120 and the material strain rate is large and the material It can be seen that the deformation section D is largely formed. In addition, it can be seen that the tapping screw according to the second prior art has a very narrow width as a whole, and thus the mechanical strength is very weak.

On the contrary, as shown in FIG. 6, the tapping screw according to the present invention includes the first flank 131, the second flank 132, and the third flank 133 so as to increase in sequence. The flank side angle is made to gradually decrease toward the outer peripheral surface of the body portion 120, so that the material flow (Fm) path of the fastening object (O) is the flank surface and body portion of the fastening thread 130 according to the present invention Since it does not change suddenly at the outer circumferential surface of 120 (because it changes very slowly), the material flow Fm of the fastening object O is not only stagnant at the outer circumferential surface of the body portion 120, but also the repulsive flow Fr. It hardly occurs, and as a result, frictional heat is hardly generated between the flank of the fastening screw 130 and the outer circumferential surface of the body portion 120 as compared with the first and second prior arts. Material deformation section It can be minimized.

As described above, the present invention can minimize the material strain and the material deformation portion of the fastening object when the tapping screw is fastened to the fastening object. Therefore, the present invention increases the fastening area of the tapping screw for the fastening object by minimizing the material strain and the material deformation portion, thereby improving the fastening force and having an effect of significantly reducing the defective rate of the fastening object itself.

As described above, in one embodiment of the present invention has been described by the specific embodiments, such as specific components and limited embodiments and drawings, but this is provided to help a more general understanding of the present invention, the present invention in the above embodiment The present invention is not limited thereto, and various modifications and variations are possible to those skilled in the art. Therefore, the spirit of the present invention should not be limited to the described embodiments, and all of the equivalents and equivalents of the claims, as well as the following claims, will fall within the scope of the present invention. .

Claims

Head; And

One end is connected to the head, the body portion is provided with a plurality of fastening screw thread on the outer circumference;

The fastening thread has a material flow resistance alleviation structure that reduces the material flow resistance of the fastening object along the outer surface of the fastening thread and the flank of the fastening thread when the fastening thread is fastened to the fastening object. Tapping screw, characterized in that provided.
The method of claim 1,

And said fastening thread is configured such that a flank angle, which is an angle between opposite flank surfaces, increases from a peak portion of said fastening thread toward a valley portion.
The method of claim 1,

The fastening screw thread,

A first flank portion positioned in the peak portion of the fastening screw thread, the first flank angle being a predetermined flank angle, the flank angle being an angle between the opposite flank surfaces;

A second flank portion extending below the first flank portion and having a predetermined second flank angle greater than the predetermined first flank angle;

And a third flank portion extending between a lower portion of the second flank portion and an outer circumferential surface of the body portion and having a predetermined third flank angle greater than the predetermined second flank angle.
The method of claim 3,

And the predetermined first flank angle and the predetermined second flank angle are within an angle range of 20 ° to 50 °.
The method of claim 3,

The predetermined first flank angle is within an angle range of 15 ° to 25 °,

The predetermined second flank angle is within an angle range of 35 ° to 45 °,

The preset third flank angle is a tapping screw, characterized in that in the angular range of 55 ° to 65 °.
The method of claim 3,

The fastening thread is a tapping screw, characterized in that the height of the first flank portion: the height of the second flank portion: the height of the third flank portion is 1: 1: 0.5 to 1.
The method of claim 3,

The fastening screw thread is characterized in that the height of the first flank portion is configured to be 0.25 to 0.5 times the sum of the height of the second flank portion and the height of the third flank portion.
The method according to any one of claims 1 to 7,

The fastening screw is configured to be configured such that the pitch of the plurality of fastening threads is 0.15 to 0.5 times the outermost outer diameter of the fastening screw thread.