KR200433761Y1 - Self-Clinching Type Fasteners - Google Patents

Abstract

The present invention relates to a self-clinching type fastener, and more specifically, using carbon steel wire rods for cold heading and cold forging, the outer peripheral edge of the barrel The present invention relates to a threaded self-clinching type fastener capable of supporting a stable and balanced electric and electronic component such as a printed circuit board by extending the other end in the longitudinal direction but reducing the thickness thereof. The self-clinching type fastener includes: a barrel having bores at both ends open to the outside of the bottom surface and the head surface, respectively; A head formed at one end of the outer circumference of the barrel; The bottom surface is formed with a protrusion formed by reducing the thickness at the other end portion of the outer peripheral edge of the barrel.

Self-clinching, fasteners, barrels, bores, heads, protrusions, enlargements

Description

Self-clinching Type Fastener

1 is a cross-sectional view showing a coupling structure of a conventional self-cleaning type fastener.

FIG. 2 is a schematic diagram schematically illustrating a manufacturing process of the self-cleaning type fastener of FIG. 1.

3 is a cross-sectional view showing the structure of another conventional self-cleaning type fastener.

FIG. 4 is a schematic diagram schematically illustrating a manufacturing process of the self-cleaning type fastener of FIG. 3.

5A and 5B are a plan view and a cross-sectional view showing the structure of a self-cleaning type fastener according to a preferred embodiment of the present invention, respectively.

Figure 6 is a schematic schematic illustrating the manufacturing process of the self-cleaning type fastener of the present invention.

7 is a cross-sectional view illustrating a tapping process for forming an internal thread of a self-clinching type fastener of the present invention.

-Explanation of symbols for the main parts of the drawings-

1: Self-clinching type fastener of the present invention

2: head

3: clinching groove 4: barrel

4c: enlarged portion 4d: protrusion

5: inclined portion 6: first bore

6a: expansion of the first bore 7: second bore

7a: 2nd bore extension 7b: screw part

8: 1st surface (bottom surface) 8a: inward inclination part

9: 2nd side (head side) 9a: inward inclination part

10: cold rolled steel wire 10a: roller shaft

10b: guide roller 11: cutting rod

11a: rough surface 12: compacted rod

12a: compaction surface 13: first intermediate workpiece

14: second intermediate workpiece

21, 22, 25, 28, 28a: grip die

21a, 21b, 23, 24, 27: Punch 26, 28a: Press die

29: punch punch 29a: distal end

29b: base 30: grip die

40: tapper 41: end portion for screw formation

42: body 50: base plate

60: printed circuit board 70: bolt

The present invention relates to a self-clinching type fastener, and more specifically, using carbon steel wire rods for cold heading and cold forging, the outer peripheral edge of the barrel The present invention relates to a threaded self-clinching type fastener capable of supporting a stable and balanced electric and electronic component such as a printed circuit board by extending the other end in the longitudinal direction but reducing the thickness thereof.

In general, a self-clinching type fastener having a screw portion therein is fixed to an electric or electronic component such as a printed circuit board of an electric and electronic device by being spaced apart from a casing or a base plate through a coupling structure of bolts and nuts. A stand-off and pop nut that prevents direct transfer of electrical and electronic components through the base plate and allows efficient heat dissipation from the electrical and electronic components. It may also be called a nut, a PEM nut, or a nut insert.

1 is a cross-sectional view showing a coupling structure of a conventional typical self-cleaning type fastener 100. The structure of the conventional exemplary self-cleaning type fastener 100 described above includes a head 2 and a clinching groove. (clinching groove) 3 and a barrel (4) having a bore (7) with a threaded portion (7b), said clinching groove (3) is installed through the casing or base plate (50) (i.e. Self-clinching) such that the outer surface of the head 2 is coplanar with the bottom surface of the casing or base plate 50, and the electrical and electronic component 60 such as a printed circuit board has a screw portion 71 having a threaded portion 71. It is fastened to the bore 7 with the screw part 7b, and the washer (not shown) is normally interposed between the said bolt 70 and the electrical and electronic component 60. As shown in FIG.

As a material of the conventional typical self-clinching type fastener 100 described above, a hot rolled wire is usually cut to a certain dimension while cold drawn (CD) in a circular or hexagonal cross section, and then polished and straightened. KS SUM24L (C 0.15 wt% or less; Mn 0.85-1.15 wt% or less; P 0.04-0.99 wt% or less; S 0.26-0.35 wt% or less; Pb 0.10-0.35 wt% or less; remainder Fe) Free cutting carbon steels) are mainly used.

FIG. 2 is a sequential schematic explanatory view showing the manufacturing process of the conventional self-clinching type fastener 100 of FIG. 1, and generally, one end of the hexagonal bar 10 'having a length of about 2.5 m is formed by the bite 45. As shown in FIG. After cutting and processing into a circular shape (in the case of a round bar, cutting to a diameter smaller than the circular diameter) to form a barrel 4, by tapping the end of the end portion using a tapper 40 to have an internal thread portion After the bore 7 is formed, the internal threaded portion 7b is cut by cutting the hexagonal head 2 portion with the bite 45 (in the case of a round rod, cutting the hexagonal shape so that the head 2 is formed). The having bore 7 is produced by forming the barrel 4 and the hexagonal head 2 formed at one end.

However, the above-mentioned free-cutting steel has good mechanical properties, particularly excellent cutting processability, and thus has the advantage of prolonging the life of the cutting tool. However, inferior adhesion of the coating film and about 40% by weight during the cutting process As the degree is cut, not only there is a serious environmental pollution problem due to the disposal of the Pb component added to improve the machinability, but also the self-cleaning fastener 100 manufactured therefrom opens the bore 7 at both ends. The cutting chip may remain inside the bore 7 because the end is closed, not in the form of perforated hole. In addition, the plating solution may not flow smoothly during the plating process in the subsequent process, resulting in poor plating. There is a problem that the economic efficiency is inferior because it is relatively high.

3 is a cross-sectional view showing the structure of another conventional self-cleaning type fastener 101, the structure of which is a collar 4a by color drawing or curling, and a deep drawing. The barrel 4, the head 2 of the outer periphery of the barrel bottom, the base 4b having an increased thickness formed adjacent to the head 2 for iron coining, It consists of a screw part 7b 'by tapping inside the collar 4a, a first bore 7' of the entire center, and a second bore 7a 'formed at the outer periphery of the collar 4a. .

Since the self-clinching type fastener 101 is manufactured by color drawing and deep drawing processing, or is manufactured by deep drawing and curling processing, a material of the above-described conventional self-clinching type fastener 101 is used. Cold rolled steel sheet for deep drawing processing (SPCE (SPCEN)) or galvanized steel sheet for deep drawing processing (Galvanized steel sheet or Zinc coated steel sheet) (SECD (SECDN)) is commonly used, especially galvanized steel sheet for deep drawing Electrolytic Galvanized Iron (EGI) is mainly used. The electro galvanized steel sheet for deep drawing is cold-rolled hot-coil (hot-coil) at a temperature reduction rate of 40% or more at room temperature to coat the surface of the cold-rolled steel sheet to which high workability is imparted, thereby improving the corrosion resistance. Since it is galvanized at room temperature without additional heat treatment, its physical properties are the same as that of cold rolled steel sheet for deep drawing.

Cold rolled steel sheet for deep drawing (SPCE: C 0.08% by weight; Mn 0.40% by weight; P 0.03% by weight; S 0.03% by weight; remainder Fe) is added a large amount of P to ensure sufficient strength and C content of 0.01% by weight A steel sheet that can withstand severe processing by using the following ultra low carbon steel. In the case of 0.8 mm thick, the tensile strength is about 32 Kg / mm2 or more, the yield strength is about 18 Kg / mm2 or more, and the elongation is It is at least 36%, usually about 45%.

FIG. 4 is a sequential schematic explanatory diagram illustrating a process of manufacturing the self-clinching type fastener 101 of FIG. 3 by color drawing the deep zinc electroplated steel sheet for deep drawing and then deep drawing. After press-cutting the galvanized steel sheet into a circle, the hole is drilled in the center, and the collar 4a is formed by color drawing. Then, the barrel 4 and its lower peripheral edge are formed by the progressive drawing step by step. After the head 2 (or flange) is formed in the base, the base portion (see reference numeral 4b in FIG. 3) having an increased thickness is formed above the head 2.

However, the conventional self-clinching type fastener 101 manufactured by using the cold rolled steel sheet or the electro-galvanized steel sheet for deep drawing is made of a sheet material, and thus, the above-described conventional self-clinching type fastener 100 is used. Self-clinching type fastener 101 manufactured using automation equipment in a number of holes drilled in the base plate (backing plate) of electrical and electronic parts such as PDP, although it is remarkably lightweight by only 1/5 of the weight. It is not only avoided from the industry due to the serious problem that it is difficult to automatically insert it in place due to its own weight due to excessively light weight when it is injected. In addition, the manufacturing process is complicated and difficult, and the color formed by color drawing The minute angular deviation or failure of (4a) is likely to directly lead to serious failure in the subsequent tapping process, and in the tapping process The formation of the threaded portion (see reference numeral 7b 'in FIG. 3) results in a thinner thickness of the collar 4, resulting in a decrease in strength, which is screwed into the threaded portion inside the collar 4a by bolts (not shown). There is a risk of product defects due to the deviation of the electrical and electronic parts to be in place, the base portion (see 4b in Figure 3) is not easy to form, if the phosphate treatment without chromate treatment, there is a problem of environmental pollution Moreover, even though the price per ton is relatively low, there is a problem in that it is not economical at all because there are many parts that need to be discarded because they have to be cut into a plurality of small circular plates for manufacturing the self-clinching type fastener 101.

Moreover, as shown in FIG. 1, the electrical and electronic component 60 such as a printed circuit board is only fastened to the bore 7 having the threaded portion 7b by the bolt 70 having the threaded portion 71. There is no limit in supporting a stable and balanced electric and electronic component such as a printed circuit board, since a seating portion in which the electronic and electronic component 60 can be easily mounted in one barrel 4 is not formed.

Therefore, the purpose of the present invention is to support the electrical and electronic components such as a printed circuit board more stably, while maintaining excellent mechanical properties and processability, and is made of environmentally friendly materials that are relatively inexpensive and do not contain heavy metal Pb or Cr. The present invention provides a self-clinching type fastener with no cutting chips remaining in the bore during tapping processing, without fear of breakdown of electrical and electronic components due to the cutting chips, easy cleaning, and excellent plating coating properties.

Self-clinching type fastener according to the present invention for achieving the above object, the barrel (barrel) having a bore (bore) open at both ends of the bottom surface and the head surface, respectively; A head formed at one end of the outer circumference of the barrel; The bottom surface is formed with a protrusion formed by reducing the thickness at the other end portion of the outer peripheral edge of the barrel.

Here, the self-clinching type fastener is preferably made of carbon steel wire rods for cold heading and cold forging material.

It is also preferred that the bore has a first bore adjacent to the head surface and a second bore adjacent to the bottom surface, wherein the diameter of the first bore is larger than the diameter of the second bore.

In addition, the thread portion is preferably formed on the inner peripheral surface of the bore adjacent to the bottom surface.

In addition, a clinching groove is formed on the outer circumferential surface of the barrel adjacent to the head, and an enlarged portion having an increased outer circumferential thickness is formed on the outer circumferential surface of the barrel adjacent to the head, wherein the base and the head are formed. Preferably, the clinching groove is formed therebetween.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

5A and 5B are a plan view and a cross-sectional view showing the structure of a self-cleaning type fastener according to a preferred embodiment of the present invention, respectively.

As shown, the self-clinching type fastener 1 according to the present invention is made of carbon steel wire rods for cold heading and cold forging material, and both ends thereof have a bottom surface 8 and a head, respectively. A barrel 4 having first and second bores 6 and 7 open to the outside of the face 9, a head 2 formed at one end of the outer periphery of the barrel 4, and the bottom The outer peripheral end of the barrel 4 having the surface 8 formed thereon is composed of a projection 4d formed with a reduced thickness.

Here, the protrusion 4d is a substantially cylindrical shape extending from the other end of the barrel 4 to reduce its outer circumferential length (diameter thickness), and the bottom surface 8 is the protrusion 4d. ) Is the front surface. By the formation of the protrusion 4d, a seating surface (not shown in the figure) is formed between the protrusion 4d and the barrel 4, whereby electrical and electronic components such as a printed circuit board are more stable on the seating surface. At the same time, it can be supported in a balanced manner.

Further, an enlarged portion 4c having an increased thickness is formed on the outer circumferential surface of the barrel 4 adjacent to the head 2, and a clinching groove is formed between the enlarged portion 4c and the head 2. (3) is formed. In this way, by the formation of the enlarged portion 4c and the clinching groove 3 having increased thickness, the outer surface of the head 2 can more stably insert and support the casing or the base plate 50 (see FIG. 1). Will be. Of course, the formation of this enlarged portion 4c is optional and as in the prior art, it is also possible to form only the clinching groove 3.

As shown, the diameter of the first bore 6 adjacent to the head surface 9 is preferably formed larger than the diameter of the second bore 7 adjacent to the bottom surface 8. 8 and the diameters of the first and second bores 6 and 7 open to the head surface 9 are of course included in the scope of the present invention.

Further, in the illustrated example, the self-clinching type fastener 1 is provided with a screw portion 7b on the inner circumferential surface of the second bore 7 adjacent to the bottom surface 8. Here, the screw portion as described above is not formed on the inner surface of the first bore 6 adjacent to the head surface 9. Of course, even if the screw portion 7b is not formed on the inner circumferential surface of the bore 7 adjacent to the bottom surface 8 described above, the enlarged portion 4c and clinching on the outer circumferential surface of the barrel 4 adjacent to the head 2 are provided. Even if the groove 3 is not formed, pinch fixing such as a forced fit fastening or the like is possible, so that the function as the self-clinching type fastener 1 can be fully performed, and thus this is also within the scope of the present invention.

In addition, a first bore extension 6a by an inwardly inclined portion 9a may be formed between the head surface 9 and the first bore 6, and the front surface of the protrusion 4d may be formed. A second bore extension 7a may be formed between the bottom surface 8 and the second bore 7, which is an inwardly inclined portion 8a, and these guide parts when the bolt (not shown) is fastened. Will be in charge. In addition, the outer periphery of the bottom surface 8 of the projection 4d is formed in the inclined portion 5 as shown in the enlarged view so as to perforate the base plate (backing plate) (not shown) of electrical and electronic components such as a PDP. It may be desirable to use an automated facility (not shown) in the hole (not shown) to facilitate the automatic insertion of the exact position due to its own weight.

Here, the overall planar shape of the head 2 is preferably hexagonal, but may be circular or polygonal, and the present invention is not limited to the shape.

Next, the cold-rolled steel wire material constituting the self-clinching type fastener 1 according to the present invention, these are SWRCH A type of aluminum-killed steel specified in KS D 7033, Among them, preferred are SWRCH 6A, SWRCH 8A, SWRCH 10A, SWRCH 12A and the like. More preferred are SWRCH 6A, SWRCH 8A, SWRCH 10A, and the most preferable is SWRCH 10A.

The chemical composition of the aluminum-kilted cold-rolled steel wire material is C: 0.05 to 0.23% by weight, preferably 0.08 to 0.13% by weight, Si: 0.10% by weight or less, Mn: 1.00% by weight or less, preferably 0.30 to 0.60. It is weight% or less, P: 0.03 weight% or less, S: 0.035 weight% or less, Al: 0.02 weight% or more, tensile strength is 28-45Kg / mm <2>, Preferably it is 30-42Kg / mm <2>, Yield strength is 18- It is 35 Kg / mm <2>, Preferably it is 18-26Kg / mm <2>, Elongation is 18 to 35%, Preferably it is 18 to 26%. Aluminum-kilted cold-rolled steel wire is called CHQ steel wire (Cold Heading Quality Wire) and has good workability and surface quality as a material for cold-rolled steel.

Subsequently, FIG. 6 which is a schematic schematic diagram showing the manufacturing process of the self-cleaning type fastener 1 of the present invention and FIG. 7 illustrating the tapping process of forming the internal thread of the self-cleaning type fastener of the present invention. This will be described.

(A) rod-shaped forming step:

    The cold rolling steel wire 10 wound in the form of a roll around the roller shaft 10a is guided by the guide roller 10b, and cut into predetermined dimensions suitable for the manufacture of the self-clinching type fastener, thereby roughing the top and bottom surfaces. The rod-shaped body 11 having the face 11a is formed.

(B) compaction surface forming step:

    As an optional step, an upset forging using a grip die 21 for opening and closing the rod-shaped body 11 up and down or left and right and a heading tool 21a or 21b for moving back and forth. The rough surface 11a of the rod-shaped body 11 is formed by the compaction surface 12a. In the illustrated example, the punches 21a and 21b are shown to move up and down for convenience of illustration. Is common).

(C) enlargement and protrusion forming step:

    A multi-stage inclined surface (not shown in the drawing number) is sandwiched on the grip die 21c so that the upper and lower ends of the rod-shaped body 12b on which the compacting surface 12a is formed are exposed, and a punching tool 21d and 21e are provided from above and below. The cold head is cold rolled into the above-described multi-sloped inclined shape to form the enlarged portion 4c and the protrusion 4d on the outer periphery of the barrel 4 as described above. Here, the formation of the enlarged portion 4c is optional.

(D) head forming step:

    The upper end of the enlarged portion 4c of the rod-shaped body 13 is sandwiched between the grip die 22 having the inclined portion 22a at a portion adjacent to the punch through hole 22b on the bottom surface, and the punch for forming the head from above. (23) is cold headed from below using the punch 24, and the circular head 2 is formed.

    The bottom face of the head forming punch 23 is larger than the diameter of the rod-shaped body 13 to form the head 2 on the rod-shaped body 13, and the head-forming punch 23 and the punch ( According to the punched end shape of 24, a dent-shaped first dent having an inclined portion (not shown) in the center of the head surface 9 of the rod-shaped body 13 on which the head 2 is formed. The bore extension part 6a is formed in the center of the bottom surface 8 of the projection part 4d, and the 2nd bore extension part 7a of the dent shape via the inwardly inclined part 8a is formed.

(E) Bore Formation Steps:

    The rod body 13 is clamped so that the head 2 is supported on the upper surface of the grip die 25, and the pressing die 26 is positioned above the grip die 25, and then cold forged (specifically, upset with a punch 27). A head-mounted rod-shaped body 14 in which a bore 7c having an extended length in the center of the barrel 4 is formed by forging is produced.

(F) Through (bore) bores forming step:

    The rod body 14 is clamped so that the head 2 is supported on the upper surface of the grip die 28, and the pressing die 28a is positioned above the grip die 28, and then cold forged (specifically, up). Through forging forms a through bore in which both ends of the barrel 4 are perforated.

    Optionally here, a wide diameter first bore 6 and a bottom surface (not shown) are opened to the head surface (not shown) by using a punching punch 29 having a diameter of the upper and lower fins. The second bore 7 having a small diameter opened in) is preferably in communication with each other to form a perforated shape.

    The self-clinching type fastener according to the present invention manufactured as described above has the point that the overall planar shape of the head 2 is circular rather than hexagonal, as compared to the self-clinching type fastener 1 shown in FIGS. 5A and 5B. Except for it is essentially the same.

(G) Head Machining Steps:

    As an optional step, the above-described self-clinching type fastener 1 is press-cut or cut so that the planar shape of the circular head 2 is hexagonal, and according to the present invention as shown in Figs. 5A and 5B. The clinching type fastener 1 is manufactured.

(H) clinching groove forming step:

    As an optional step, the outer circumferential surface of the enlarged portion 4c of the barrel 4 adjacent to the head 2 of the self-clinching type fastener 1 before, after, or at the same time as the head machining step G described above. The self-clinching type fastener 1 according to the present invention is formed by forming the clinching groove 3 in the rotary cutting by a single bite or by partial rotational cutting by the mutual reciprocating motion of a double linear blade.

(I) Tapping Steps:

    As an optional step, before or after the above-described clinching groove forming step (H), or at the same time, the threaded portion 7b on the inner circumferential surface of the bore 7 (second bore) adjacent to the bottom surface using the tapper 40. ).

    Here, the inner circumferential surface of the second bore 7 of the self-clinching type fastener 1 when the bore is formed of a first bore 6 having a different diameter and a second bore 7 having a slightly smaller diameter. Referring to the cross-sectional view illustrating a tapping process for forming a threaded portion (not shown) in the drawing, the barrel 4 can be clamped to the grip die 30 (the head side can be clamped to prevent damage to the head portion). And a tapper 40 having a threaded tip 41 and a body 42 from the first bore 6 having a larger diameter on the head side to a second bore 7 having a smaller diameter. When the inner side of the first bore 6 is tapped, the inner diameter of the first bore 6 is larger than the outer diameter of the tapper 40 so that the inner space of the first bore 6 is spaced by the tolerance C. Since the tapping operation on only the inner circumferential surface of 7) is performed, In addition to minimizing the occurrence, cost savings due to improved process efficiency due to shorter tapping workload and shorter tapping operation time can be achieved, and the life of the tapper can be extended.

The method of manufacturing the self-clinching type fastener of the present invention has been described above. However, if the above-mentioned matters are addressed, the method may be further passed through a normal deoiling step, a cleaning step, a plating step, a packing step, a inspection step for dimensions and surface conditions, and the like. Of course you can.

As described above, according to the self-clinching type fastener according to the present invention, by forming a cylindrical protrusion having a reduced thickness extending in the longitudinal direction at the other end of the outer peripheral portion of the barrel more stable electronic and electronic components such as a printed circuit board In addition, it can be supported in a balanced manner, and is made of cold-rolled steel wire, which is an environmentally friendly material, and the cutting chips do not remain inside the bore during tapping, so there is no fear of breakdown of electrical and electronic components due to the cutting chips. It is easy to use and has excellent coating coating property, and it has proper self weight so that it can be automatically inserted in position due to its own weight when it is put in by using the automation equipment in the hole drilled in the base plate (backing plate) of electric and electronic parts such as PDP. It is easy and has the effect of shortening the tapping processing time and consequently extending the tool life.

Claims (6)

A barrel having a bore open at both ends of the bottom surface and the outside of the head surface; A head formed at one end of the outer circumference of the barrel; A self-clinching type fastener comprising a protrusion formed by reducing the thickness at the other end of the outer periphery of the barrel having the bottom surface. The self-clinching type fastener as claimed in claim 1, wherein the fastener is made of carbon steel wire rods for cold heading and cold forging. 2. A self-assembly as set forth in claim 1 wherein said bore has a first bore adjacent to a head face and a second bore adjacent to a bottom face, wherein the diameter of said first bore is greater than the diameter of said second bore. Clinching Type Fasteners. The self-cleaning type fastener according to any one of claims 1 to 3, wherein a thread is formed on an inner circumferential surface of the bore adjacent to the bottom surface. The self-clinching type fastener according to any one of claims 1 to 3, wherein a clinching groove is formed on an outer circumferential surface of the barrel adjacent to the head. The self-circumference according to claim 5, wherein an enlarged portion having an increased outer circumferential thickness is formed on an outer circumferential surface of the barrel adjacent to the head, and a clinching groove is formed between the base and the head. Clinching Type Fasteners.

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