JP4947818B2 - Stud manufacturing method and bulging portion forming pin used therefor - Google Patents

Description

  The present invention relates to a stud manufacturing technique applied to, for example, a steel structure in the field of construction and civil engineering, and more particularly to a manufacturing method thereof and a bulge forming pin used therein.

  Conventionally, in a steel structure in the field of construction or civil engineering, concrete is integrated with a steel column and a steel beam in terms of fire resistance and structural strength. In this case, as a means for improving the proof stress by increasing the mutual connectivity between the members, it is common to implant a stud material called a stud bolt, a headed stud, etc. on the steel surface by arc welding. Is. As this type of stud, a small lump made of a highly conductive material such as aluminum is attached to the center portion of the stud-side end surface (stud base) of the stud body so that a part thereof protrudes from the surface. (For example, refer to Patent Document 1, Patent Document 2, and Patent Document 3.) This metal lump plays a role as a flux that causes a deoxidation reaction during arc generation with the base metal, in addition to a role as an energizing terminal at the start of welding.

Japanese Examined Patent Publication No. 52-10648 (first page, second column, third line—same column, twenty-seventh line and FIG. 6; and second page, third column, twelveth line—same column, seventeenth line and FIG. 4) Japanese Utility Model Publication No. 57-54932 (page 1, column 2, line 1, column 21, line 21, FIGS. 3-6) Japanese Patent Publication No. 7-55352 (page 3, column 6, line 20 to page 4, column 7, line 7, FIG. 4)

  By the way, in the stud of the above-described conventional example, a concave portion having an appropriate depth is formed in advance in the center portion of the end surface on the side of the molten metal into which the metal lump is press-fitted by punching (also referred to as punch). As shown in Patent Documents 1 and 3, such a recess is generally circular in cross-sectional shape in the axial direction, and its inner peripheral surface is formed as a relatively smooth surface. This is due to the fact that the outer peripheral surface of the punch is finished to be a smooth surface in order to prevent the punch from biting into the stud body at the time of stamping. Accordingly, since the press-fitted metal lump is substantially locked to the stud body only by friction with the inner peripheral surface of the recess, there is a problem that it is easy to drop off even with a slight impact. .

  Patent Document 2 discloses a technique for forming a large number of irregularities on a wall surface by forming the recess into a cross-sectional shape other than a circle such as a star, or by forming the inner peripheral surface of the recess in a horizontal stripe shape or a spiral shape. Although disclosed, each has the following problems. That is, in the former case, the contact area with the metal block is increased as compared with the circular cross section as described above, but there is no step in the axial direction, and the contact area with the circular cross section is as follows. Similarly, it is a lock only by friction. For this reason, not much improvement can be expected in terms of prevention of dropout. In the latter case, the plastic deformation at the time of press-fitting of the metal lump can be expected to have a latching effect on a large number of steps formed in the axial direction, but the forming process is quite troublesome and the manufacturing cost is low. Therefore, it has not been put into practical use.

  Under such circumstances, a method of making a hole with a drill instead of punching has recently been widely used. In this case, since the annular cutting trace accompanying the rotation of the drill blade is formed on the inner peripheral surface of the recess, a slight engagement state occurs between the press-fitted metal lump and the metal lump There is less dropout. However, this method of forming a recess by a drill has a problem that workability is poor compared to punching and a large amount of cutting waste is generated, and is not an essential solution. .

Therefore, the present inventors have come up with the present invention as a result of intensive studies on the problems of such conventional techniques. That is, an object of the present invention is to provide a method for manufacturing a stud that can be manufactured at low cost without dropping off a metal lump and a bulging portion forming pin used for the stud.

In order to solve the above-mentioned problem, in the stud manufacturing method according to claim 1, after forming a recess in the blast side end surface of the stud body, a truncated cone part that presses the blast side end surface on the tip side, and at the center thereof The blasting side in the vicinity of the recess while restricting the inner peripheral surface of the recess with a bulging portion forming pin having a protrusion formed in a two-stage shape that is projected and protrudes into the recess when pressing the end surface on the side of the implantation By pressing the end surface in the axial direction with the projection, at least a part of the peripheral edge portion of the opening of the recess is plastically deformed so as to bulge inward, and then a metal lump that is softer than the stud body Is inserted into the back side of the bulging part while being plastically deformed by press-fitting into the recessed part of the stud body, and a part thereof is engaged with a state protruding from the end face on the side of the stud body. It is characterized by that.

According to the above configuration, the stud main body is formed using an appropriate forging device, and after forming the concave portion on the end surface of the vegetation side, the blast side is formed at the truncated cone portion of the protrusion at the tip of the bulging portion forming pin. The vicinity of the recess on the end face is pressed in the axial direction. The part that has received this pressing force is plastically deformed and recessed from the surrounding end face on the side of the vegetation, and along with the deformation, the opening peripheral part of the recessed part bulges inward, and the opening part of the recessed part is narrowed. At this time, the columnar portion of the protrusion of the bulging portion forming pin restricts deformation on the inner peripheral surface side of the recess, thereby preventing the opening peripheral portion from bulging inwardly more than necessary. The metal lump climbs over the bulging portion on the inner surface of the concave portion where the amount of bulging is restricted while plastically deforming along with the press-fitting, enters the concave portion, and wraps around the back side of the bulging portion. It will be securely hooked to the part.

With bulging portion forming pin according to the claim 1, it is possible to produce the stud there is no separation of the metal lumps economically (claim 2).

  Moreover, as a recessed part formed in the blasting side end surface of the stud main body to which the bulging part forming pin according to the present invention is applied, a substantially hemispherical shape is preferable, and when forming a recessed part using a punch, a mold is manufactured. This is advantageous in terms of cost and durability.

  According to the present invention, excessive bulging of the peripheral edge of the opening of the concave portion is performed by pressing the end surface on the side of the molten metal near the concave portion of the stud body in the axial direction while regulating the inner peripheral surface side of the concave portion with the bulging portion forming pin. Since it is configured to prevent the protrusion, this bulging portion is unlikely to become an obstacle in the press-in operation of the metal lump in the next process, and it is possible to reliably prevent the metal lump from falling off by a simple method. In addition, a reduction in manufacturing cost can be achieved.

The stud manufacturing method according to the present invention is substantially effective until the stud main body is formed using an appropriate forging apparatus generally used such as a multi-stage former, and the concave portion is formed on the end face on the side of the weld. Is not much different from the conventional method. In the present invention, a bulging portion forming pin is newly developed, and the peripheral portion of the opening (the inner surface near the inlet of the concave portion) is high by pressing the vicinity of the concave portion on the side surface of the blasting side while regulating the inner peripheral surface side. It has a technical feature in that it is bulged inward with dimensional accuracy, and a metal lump is hooked on the stud body at this bulge. The metal lump applied to the present invention is a softer metal than the stud body. Furthermore, it is a metal having a lower melting point and a stronger reducing power than the metal constituting the stud body and the base material. For example, for iron, which is a representative material of the stud body and the base material, aluminum, zinc, etc. What is necessary is just to select suitably according to the metal used as object. The shape is not particularly limited, but a spherical shape, a pointed columnar shape, or the like is preferable. The type of stud is not limited to a headed stud, and there is no particular limitation in the shape of the main body, such as a seismic reinforcement stud made of deformed reinforcing bars. Moreover, about the formation method of the bulging part in the recessed part in the blasting side end surface of a stud main body, it protrudes in the center and the recessed part when it presses the blasting side end surface. A two-step projection consisting of a columnar part that enters inside is pressed in the axial direction with an appropriate punch formed on the tip surface to cause plastic deformation, and thereby the entire circumference of the inner surface near the entrance of the recess the Ru swelled.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a partial sectional front view showing an embodiment of a stud obtained by the manufacturing method according to the present invention. The stud 1 shown in the figure is fixed to the center of an end surface 12 serving as a stud base on the side opposite to the head 11 of the stud body 10 in a state in which a metal lump 13 such as an aluminum sphere is partially buried. Is. Here, as shown in an enlarged view in FIG. 2, a part of the metal lump 13 is inserted into a substantially hemispherical recess 14 provided in the stud body 10, and the exposed portion is in contact with the spherical portion 13a. It is part 13b. And the metal lump 13 is formed over the inner surface near the entrance of the recess 14, that is, the entire periphery of the peripheral edge of the opening, and on the back side of the bulging portion 14a that swells inward to narrow the opening (inlet). Wraps around and fills the inside of the recess 14 in a close contact state with almost no gap. Thus, in the stud 1 of the present invention, the metal lump 13 is reliably locked by engaging with the bulging portion 14a of the stud main body 10 on the back side, and may fall off from the stud main body 10. Disappear.

  Next, a method for manufacturing the stud 1 using a multistage former will be described with reference to FIGS. 3 to 8. The multi-stage former is generally composed of a plurality of dies attached to a fixed base (not shown) and a plurality of punches attached to a reciprocating ram (not shown). In FIG. 3, a rod-shaped material 2 such as an iron wire having a predetermined outer diameter cut to a predetermined length is first inserted into the die 20 leaving a predetermined length portion serving as a head, and is supported by a support pin 21 on the rear end side. Supported. In this state, the punch 22 moves from the tip side, the tapered inner space 22a is fitted on the protruding end of the rod-shaped material 2, and the head is preformed by pressing with the punch pin 23. .

  Next, as shown in FIG. 4, the head is further formed by the die 24 and the punch 25 in the unit of the next process. Here, while the rear end side is in contact with the concave portion forming pin 26 inserted through the die 24, the head is further formed by the punch pin 27, and an intermediate concave portion is formed on the rear end surface of the rod-shaped material 2. . Note that the shape of the pressing portion 26a in the concave portion forming pin 26 is a hemispherical shape with the tip side somewhat flattened, and as shown in an enlarged view in FIG. It is formed in a corresponding shape.

  Subsequently, as shown in FIG. 6, the head of the rod-shaped material 2 is finally formed by the die 28 and the punch 29 in the next process unit. At this time, a cylindrical protrusion 31a having an outer diameter slightly larger than the inlet of the recess 2a is formed at the tip with respect to the intermediate recess 2a (see FIG. 5) formed on the rear end surface of the stud body 10. In the state where the bulging portion forming pin 31 is attached to the punch 29, the punch pin 30 in the punch 29 is pressed from the head side. By this pressing, as shown in FIG. 7, the vicinity of the entrance of the recess 2a at the intermediate stage is plastically deformed and bulges inward on the entire circumference, thereby forming an annular bulge 14a. In this way, the final concave portion 14 is formed by forming the bulging portion 14a by plastic deformation at the peripheral edge portion of the opening (the inner surface near the entrance of the concave portion 2a). Note that the bulging portion forming pin 31 in FIG. 6 is a reference example, and the protruding bulging portion forming pin 32 shown in FIG. 8 relates to the present invention. In this case, the protrusion is formed in a two-stage shape including a truncated cone portion 32a and a cylindrical portion 32b. Here, the reason why the cylindrical portion 32b is provided at the center is that the cylindrical portion 32b is located inside the concave portion 2a (14) when pressing the vicinity of the entrance of the concave portion 2a at the intermediate stage with the truncated cone portion 32a near the main body portion. Intrusion restricts the peripheral edge portion of the opening that finally becomes the bulging portion 14a from being plastically deformed more than necessary and bulging inward, thereby facilitating the press-fitting work of the metal lump 13 described later. Because.

  FIG. 9 shows an outline of the press-fitting work of the metal lump 13 which is the final process of stud production. In this case, an aluminum sphere is used as the metal lump 13. Here, the head body 11 side of the stud main body 10 is inserted into the punch case 33 and supported by the punch pins 34. In this state, the through hole 35a of the driving die 35 is placed in alignment with the concave portion 14 of the stud body 10 so that the axis of each other is aligned, and the aluminum sphere 13 is press-fitted into the concave portion 14 with the driving pin 36. The aluminum balls 13 are supplied one by one into the through hole 35a from a storage portion 37 provided at the tip side portion of the driving die 35. By this press-fitting operation, the aluminum sphere 13 enters the inside of the recess 14 while being plastically deformed, and fills the inside and swells in close contact with the inner surface of the recess 14 as shown in FIG. It also wraps around the back side of the protruding portion 14a. After that, the stud body 10 to which the aluminum sphere 13 is engaged is pushed forward by the punch pin 34 after the punch case 33 is retracted, and the driving pin 36 is also returned to the original position by the spring 38, and the next work is performed. Prepare for. As can be seen from FIG. 2, the aluminum sphere 13 is securely hooked to the bulging portion 14a by forming a concave-convex relationship with each other in the axial direction. On the other hand, it will not fall out. In addition, the collar part 13b shown in FIG. 2 is formed by protruding an excessive volume part during the press-fitting.

10 through 15 are reference examples of the stud body to be produced and the bulging out part forming pin, thereby. First, FIGS. 10 and 11 will be described. The bulging portion forming pin 40 shown in the figure has a columnar portion 40b for restricting bulging more than necessary, like the bulging portion forming pin 32 shown in FIG. In this case, the protrusion 40a for forming the bulging portion by plastic deformation on the stud body is annularly formed at a predetermined interval outside the cylindrical portion 40b, that is, at a position outside the opening of the recess 2a at the intermediate stage. Is provided. FIG. 11 is a cross-sectional view of a stud main body 41 manufactured using the bulging portion forming pin 40. The periphery of the entrance of the concave portion 42 is pressed by the annular protrusion 40a of the bulging portion forming pin 40 and is plastically deformed. As a result, as the annular groove 42a is formed on the end surface, the bulging portion 42b is formed over the entire periphery of the opening peripheral edge portion (the inner surface near the entrance of the recess 42).

In the reference example shown in FIGS. 12 and 13, the protrusion 50a of the bulging portion forming pin 50 is formed in a cross shape. Here, the length of one side of the cross is formed to be somewhat larger than the inner diameter so as to straddle the entrance portion of the recess 52 of the stud body 51. When this bulging portion forming pin 50 is used, four bulging portions 52a are formed by plastic deformation independently in the vicinity of the entrance of the concave portion 52 of the stud body 51. Although not shown, a columnar portion for restricting bulging as in the above-described embodiment and reference examples (FIGS. 8 and 10) may be provided at the center of the cross of the bulging portion forming pin 50. It is essential.

Further, in the reference example shown in FIGS. 14 and 15, four protrusions 60 a are arranged on the tip surface of the bulging portion forming pin 60 at a cross-shaped position sandwiching the axis. Here, the interval between the protrusions 60 a in the opposing relationship is formed to be somewhat larger than the inner diameter of the stud body 61 near the entrance of the recess 62. When such a bulging portion forming pin 60 is used, as shown as an end surface in FIG. 15, the influence of the four recesses 62a formed on the end surface due to the pressing of the protrusion 60a of the bulging portion forming pin 60. As each axial center side portion is plastically deformed and bulges, a bulging portion 62b is formed. Although not shown, it is also essential to provide a cylindrical portion as in the above-described embodiment and reference examples (FIGS. 8 and 10) at the center of the four protrusions 60a.

Next, FIGS. 16 to 18 are reference examples in which the manufacturing method is slightly different from the above-described embodiments. In this case, as shown in FIG. 16, the shape of the pressing portion 70a in the concave portion forming pin 70 for forming the concave portion in the stud body first is basically the same as that of each of the above embodiments and reference examples . An annular groove 70b that is recessed from the end face is provided outside the pressing portion 70a. By using this recess forming pin 70, as shown in FIG. 17, the end surface of the rod-shaped material 3 is formed with an intermediate recess 3a by plastic deformation and an annular protrusion 3b. Next, when the protrusion 3b is pressed in the axial direction on the end face of the rod-shaped material 3 with a bulging portion forming pin (not shown) having a flat end face, the protrusion 3b is plastically deformed and crushed as shown in FIG. Due to the influence, the vicinity of the entrance of the recess 3a swells, and the stud body 71 is formed with the recess 72 having an annular bulge 72a due to plastic deformation.

In each of the above examples and reference examples , the concave portion of the stud main body has been described as having a circular cross section in the axial direction, but this is made into a polygonal shape, or a metal lump other than a sphere, etc. Of course, various modifications within the technical concept of the present invention are possible.

It is a fragmentary sectional front view which shows one Example of the stud manufactured by this invention. It is a principal part expanded sectional view of the said stud. It is explanatory drawing which shows the manufacturing process of a stud main body. It is explanatory drawing which shows the next process of FIG. FIG. 5 is an enlarged cross-sectional view of a main part of an intermediate stud body formed in the process of FIG. 4. It is explanatory drawing which shows the next process of FIG. It is a principal part expanded sectional view of the stud main body finished by the process of FIG. It is a principal part expanded sectional view which shows one Example of the bulging part formation pin which concerns on this invention. It is explanatory drawing which shows the press injection operation | work of a metal lump. It is a principal part expanded sectional view which shows the reference example of the bulging part formation pin which concerns on this invention. It is a principal part expanded sectional view of the stud main body formed with the bulging part formation pin of FIG. It is a principal part expanded sectional view which shows the other reference example of a bulging part formation pin. It is a principal part expanded sectional view of the stud main body formed with the bulging part formation pin of FIG. It is a principal part expanded sectional view which shows the other reference example of a bulging part formation pin. FIG. 15 is an enlarged end view of a stud body formed with the bulging portion forming pin of FIG. 14. It is a principal part expanded sectional view which shows the reference example of a recessed part formation pin. It is a principal part expanded sectional view of the stud main body of the intermediate | middle stage formed with the recessed part formation pin of FIG. It is a principal part expanded sectional view of the stud main body finished by the next process of FIG.

DESCRIPTION OF SYMBOLS 1 ... Stud, 2, 3 ... Bar-shaped material 10, 41, 51, 61, 71 ... Stud main body, 11 ... Head, 12 ... End surface on the side of a blast, 13 ... Metal lump, 14, 42, 52, 62 72, recesses, 14a, 42b, 52a, 62b, 72a ... bulging parts, 20, 24, 28 ... dies, 22, 25, 29 ... punches, 26, 70 ... recess forming pins, 31, 32, 40, 50 , 60 ... bulge forming pin, 33 ... punch case, 35 ... die for driving

Claims (2)

After forming a recess in the stud end surface of the stud body, a truncated cone portion that presses the end surface on the tip side and a columnar portion that protrudes in the center and enters the recess when pressing the end surface on the weld side The peripheral edge of the recess is pressed by the protrusion in the axial direction while restricting the inner peripheral surface of the recess with a bulging portion forming pin having a protrusion formed in a two-stage shape. At least a part of the portion is plastically deformed to form a bulging portion that bulges inward, and then a metal lump that is softer than the stud main body is filled into the concave portion while being plastically deformed by press-fitting into the concave portion of the stud main body. The stud manufacturing method, wherein the stud is also inserted into the back side of the bulging portion, and a part of the bulging portion is engaged with a state of protruding from the end surface of the stud main body on the side of the blasting. Bulging portion forming pin used in the manufacturing method of the stud, as described in the claim 1.

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