JP2006297444A - Method for manufacturing box nut - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a box nut with which the box nut can be manufactured in the good state from the flat-platy metal blank with pressing working. <P>SOLUTION: This manufacturing method comprises; a cup-forming process (b), in which the flat-platy metal blank 10 is press-worked into the cup-shape; a female screw forming process (c), in which the metal blank 10 formed as the cup-shape in the cup-forming process (b) is outer-fitted to a screw-mold 42 and the box nut 20 forming a female screw in the inner surface following to the screw mold 42 by press-forming so as to shrink the outer diameter and extend the whole length is formed; and a screw mold-taking out process, in which the screw mold 42 is taken out from the box nut 20 formed in the female screw forming process (c) by rotating the screw mold 42 (the arrow mark A). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a cap nut, and more particularly, to a method for manufacturing a cap nut that manufactures a cap nut having a female screw and a bottom by press molding from a flat metal material.

  The cap nut is used to close the end of the pipe, cover the tip of the screwed bolt, etc., is formed in a substantially cup shape, and has an internal thread on the inner surface, It has a bottom on one end side in the axial direction. In addition, as a kind of cap nut, there is one with a through-hole drilled in the bottom, such a cap nut functions as a flange with the bottom extending inward, for connecting piping etc. Used. And there exists a metal thing as a cap nut, Since such a metal cap nut has a female screw, it was generally manufactured by cutting a metal raw material.

  The above background art is a general matter, and the applicant of the present application has no particular knowledge of documents describing this background art at the time of filing.

  When a cap nut is manufactured by cutting, it is difficult to manufacture it in a short time. In addition, since the material is removed from the metal material by cutting, the entire material of the metal material cannot be used effectively. Therefore, it is possible to manufacture the cap nut in a short time compared to the cutting process, and it can be simply assumed that the cap nut is manufactured by pressing that can effectively use the entire material of the metal material. Because it is cup-shaped and has a female screw, even if it is to be manufactured by pressing from a flat metal material, it is simply to accurately produce a cap nut of the desired shape. I can't. Note that pressing is a technique for plastically deforming a metal material to obtain a desired shape, and is a kind of forging, but a metal material is placed between a die mold and a punch mold to The metal material is subjected to plastic deformation by pressing the punch die, and the metal material is plastically deformed into a shape following the die die and the punch die by one stroke of the punch die with respect to the die die. This is a possible processing method.

  This invention is made | formed in view of the said actual condition, and makes it a subject to provide the manufacturing method of a cap nut which can manufacture a cap nut favorably from a flat metal material by press work.

The main means taken by the present invention to solve the above problems are as follows:
"Cup forming process to press-mold a flat metal material into a cup shape,
A female screw imitating the screw mold by press-fitting the metal material molded in a cup shape in the cup forming process onto the screw mold to reduce the outer diameter and extend the entire length. An internal thread forming step for forming a cap nut formed on the inner surface;
A screw nut manufacturing method comprising: a screw mold extracting step of rotating the screw mold and extracting the screw mold from the cap nut formed in the female screw forming step.
It is.

  In the method of manufacturing a cap nut having the above-described configuration, a flat metal material is press-molded into a cup shape in the cup forming step, and then the metal material is externally fitted to the screw die in the female screw forming step to form a screw die. Form the copied female thread. Therefore, according to the manufacturing method of the cap nut of the said structure, a cap nut can be favorably manufactured from a flat metal raw material by press work.

  In addition, the female screw formed in the female screw forming process is screwed into the screw mold, but in order to rotate the screw mold and remove it from the cap nut in the screw mold extracting process. The cap nut that has undergone the screw mold removal process is not screwed into the screw mold. Therefore, the cap nut that has undergone the screw die removal process can be smoothly taken out from the press die constituted by the die die or punch die of the press machine.

  By the way, in the female screw forming step, the metal material press-molded into a cup shape is press-molded so that the outer diameter is reduced and the entire length is extended, so that the inner surface material is a screw-type screw. The groove flows and fills well. Therefore, in this female screw forming step, a female screw that follows the screw shape is satisfactorily formed.

In the above means,
“The method for producing a cap nut, wherein the metal material is a copper alloy”
It is good.

  Copper alloys are superior in plasticity compared to other metal materials represented by steel, and can be greatly plastically deformed by press molding. Therefore, by using a copper alloy as the material of the metal material, a cap nut having a desired shape can be accurately formed by press molding.

In the above means,
“A method of manufacturing a cap nut, wherein the female screw is a taper screw”
It is good.

  If the female screw is a taper screw, slightly screwing the screw die loosens the screwed state between the screw die and the cap nut, so the screw die is smoothly removed from the cap nut during the screw die removing process. can do. Also, in the female screw forming process, when the material on the inner surface of the metal material press-molded into a cup shape is made to flow following the screw mold, the material on the inner side of the cup-shaped metal material has to flow greatly. On the other hand, since the material on the opening side only needs to be flowed small, it is easy to obtain a desired shape for the end portion on the opening side of the cup shape that is difficult to be plastically deformed by press molding, and the female screw can be accurately formed. .

  As described above, according to the present invention, a cap nut can be favorably manufactured from a flat metal material by press working.

  Hereinafter, an example as an embodiment of a manufacturing method of a cap nut concerning the present invention is explained in detail according to a drawing. In the following description, one unit includes a punching stage that performs press working in the punching process, a cup forming stage that performs press working in the cup forming process, and a female screw forming stage that performs processing in the female screw forming process. An example of a manufacturing method for press-molding a cap nut from a metal material with the press machine of FIG.

  In such a press working machine, corresponding punching dies (die dies and punch dies) are mounted on the punching stage, the cup forming stage, and the female screw forming stage, respectively. The punching process is performed on the metal material of the punching stage by one reciprocating operation in which each punch die raised with respect to each die die is lowered to press-mold the metal material and then the punch die is raised again. However, the cup forming process is applied to the metal material of the cup forming stage, and the female screw forming process is applied to the metal material of the female screw forming stage. Also, supply of materials to the press machine, conveyance of the metal material processed at the punching stage to the next cup formation stage, and the next female screw formation stage of the metal material processed at the cup formation stage Each of the transporting to and the taking-out of the cap nut formed at the female screw forming stage from the press machine is performed by an appropriate transport device provided in the press machine.

  In the manufacturing method using the press machine described above, first, as shown in FIG. 1A, in a punching process at a punching stage, a copper alloy, specifically brass, more specifically C2600 (JIS). The rolled material having a uniform plate thickness is punched out using the stipulations) as a material to form a flat and disk-shaped metal material 10 that becomes individual cap nuts. Here, in this example, a metal rolled material having a plate thickness of 3 mm is punched to form a disk-shaped metal material 10 having a diameter of 40 mm.

  By the way, the material of the metal material 10 may be any material that can be press-molded, such as a copper alloy, an aluminum alloy, a titanium alloy, steel such as stainless steel and carbon steel, etc. It is preferable to employ a material having excellent plasticity that can be largely plastically deformed by molding. In particular, cap nuts used as parts for pipes such as water pipes and gas pipes are generally formed of brass with excellent rust prevention, and brass is a material with superior plasticity than steel. When manufacturing a cap nut used as a piping component, it is preferable to employ brass as the material of the metal material 10.

  Next, in the cup forming step at the cup forming stage, as shown in FIG. 1B, a disk-shaped metal material 10 is disposed between the die die 30 and the punch die 31 that are press dies, By pressing the punch die 31 against the die 30 and press-molding the metal material 10, the disk-shaped metal material 10 is plastically deformed into a cup shape. Here, in this example, the outer diameter is 27 mm, the inner diameter is 21 mm, and plastic deformation is performed in a cup shape having a total length of 10 mm. In this example, since the end of the cup-shaped metal material 10 on the opening side is not restricted by the die mold 30 and the punch mold 31 and is opened, the end surface portion of the cup-shaped metal material 10 is freely plastically deformed. The Therefore, the above-mentioned total length is not an accurate dimension over the entire circumference of the cup-shaped metal material 10, but is an approximate dimension. By constraining with the die 30 and the punch die 31, the shape of the end portion may be a shape that follows the die die 30 and the punch die 31, and the entire length may be an accurate dimension.

  By the way, the thickness of the cylindrical portion of the cup-shaped metal material 10 is 3 mm, which is almost the same as the thickness of the disk-shaped metal material 10. Compared to the thickness of the metal material 10, it may be slightly thinner. Thus, the disk-shaped metal material 10 can be favorably plastically deformed into a cup shape by press molding so that the thickness of the cylindrical portion is thinner than the original plate thickness. Further, when the thickness of the cylindrical portion of the cup-shaped metal material 10 is made thin, if it is made too thin, it will not be possible to secure a sufficient thickness to form a female screw to be described later. It is desirable to ensure a wall thickness of at least 80%, specifically at least 90%, more specifically at least 95%.

  Next, in the female screw forming step in the female screw forming stage, the cup-shaped metal material 10 is fitted to the outside of the screw die 42 as shown in FIG. Then, the punch die 41 is pressed to further press-mold the cup-shaped metal material 10. Then, the cap nut 20 which has the external shape which followed the die type | mold 40 and the punch type | mold 41, and has the internal thread 22 which copied the screw type | mold 42 on the inner surface is formed. Here, in this example, the outer diameter of the cup-shaped metal material 10 is reduced to 24 mm, and the entire length is extended to 14 mm. In this example, the end of the cap nut 20 on the opening side is constrained by the die mold 40 and the punch mold 41 and press-molded into an end shape that follows the die mold 40 and the punch mold 41. The end portion on the opening side of the nut 20 may be opened without being constrained by the die mold 40 and the punch mold 41 so that the end portion shape is freely plastically deformed. In this case, the end portion of the cap nut 20 may be processed into a desired shape by separate press processing, cutting, or the like to obtain a finished product of the cap nut 20.

  In this example, a pipe taper screw Rc1 / 2 (JIS standard) is formed as the female screw 22 in the female screw forming step. However, the screw mold 42 is a pipe taper screw R1 that is a corresponding male screw. / 2 (JIS standard), and the effective diameter of the thread is about 19.8 mm, whereas the inner diameter of the cylindrical portion of the cup-shaped metal material 10 is 21 mm. Since it is larger than the effective diameter of the screw thread, the cup-shaped metal material 10 can be satisfactorily fitted onto the screw mold 42.

  In order to fit the cup-shaped metal material 10 to the screw mold 42 satisfactorily, the inner diameter of the cup-shaped metal material 10 is at least 0.1 mm, preferably at least 0, larger than the maximum diameter of the screw mold 42. It is preferred to increase it by 0.5 mm, more preferably at least 1 mm. On the other hand, if the inner diameter of the cup-shaped metal material 10 is too larger than the maximum diameter of the screw mold 42, the cup-shaped metal material 10 that is externally fitted to the screw mold 42 will have a large backlash. Therefore, it is preferable that the inner diameter of the cup-shaped metal material 10 is slightly larger than the maximum diameter of the screw mold 42, such as at most 5 mm, preferably at most 3 mm, more preferably at most 2 mm. .

  Thus, the cap nut 20 formed in the female screw forming step in the female screw forming stage is in a state in which the screw die 42 is screwed and cannot be removed from the press machine as it is. Therefore, in the screw mold removing process at the female thread forming stage, the screw mold 42 is rotated with respect to the cap nut 20 (arrow A in FIG. 1C), and the screw mold 42 is removed from the cap nut 20. Let Here, since the female screw 22 of the cap nut 20 is a taper screw, if the screw die 42 is slightly rotated, the screwed state between the cap nut 20 and the screw die 42 is greatly loosened. 42 can be smoothly removed. In the aspect in which the cylindrical portion of the cap nut 20 is circular and the cap nut 20 is rotatable to the punch die 41 or the die die 40, the screw die removing step is performed with respect to the die die 40. If it is performed in a state where 41 is pressed, the screw mold 42 can be accurately rotated with respect to the cap nut 20 in a state where the cap nut 20 is firmly fixed by the die mold 40 and the punch mold 41. Is preferred. On the other hand, if the cap nut 20 is configured to be unable to rotate with respect to the die mold 40, the screw mold 42 is rotated with respect to the die mold 40 while the punch mold 41 is separated from the die mold 40. Further, a screw mold extracting / removing step can be performed.

  By the way, the outer shape of the cap nut 20 is formed by the punch die 41 in the female screw forming step, but is not limited to the circular shape, and for example, as shown in FIGS. 2 (a) and 2 (b) It is good also as a shape which has tool hanging surfaces 23, such as a surface. In this case, the cup-shaped metal material 10 formed in the cup formation step is reduced in outer diameter in the female screw formation step to form the tool hooking surface 23, and the reduced amount of material is used. The internal thread 22 is formed on the inner surface by flowing.

  In this case, since the cup-shaped metal material 10 cannot be uniformly plastically deformed over the entire circumference in the female screw forming step, as shown in FIG. While the desired shape can be obtained sufficiently for the thread valley 22 (two-dot chain line a in the figure), the thread (two-dot chain line b shown in the figure) of the female screw 22 is partially missing (the arrow c portion in the figure). ) May occur. However, even if the thread is deficient in this way, the function as the female screw 22 can be ensured by the part (part indicated by the arrow d in the figure) where a sufficient shape as the thread is obtained.

  Next, the cap nut 20 manufactured in this way has a bottom portion 21 at one end, an opening at the other end, and an internal thread 22 engraved on the inner surface. This will be described with reference to FIGS.

  The cap nut 20 shown in FIG. 3 can completely close the end of the pipe 50. As shown in the figure, a packing 52 is interposed between the end face of the pipe 50 and the bottom 21 of the cap nut 20, and the cap nut 20 is screwed onto a male screw 51 engraved on the outer surface of the end of the pipe 50. Thus, the cap nut 20 can be used as a sealing cap that seals the end of the pipe 50. Although illustration is omitted, if at least one of the male screw 51 or the female screw 22 is a pipe taper screw, the packing 52 is omitted and a sealing tape is wound around the male screw 51 engraved on the outer surface of the pipe 50. In addition, the cap nut 20 may be screwed to the pipe 50.

  The cap nut 20 shown in FIG. 4 has a through-hole 24 formed in the bottom portion 21 and can function as a flange extending inwardly. As shown in the drawing, a first pipe 60 having a flange 61 extending outward at the end is inserted through the through hole 24 of the bottom 21 of the cap nut 20, and the end face of the flange 61 of the first pipe 60 is inserted. The cap nut 20 is screwed onto the male screw 64 of the second pipe 63 with the packing 62 interposed between the end face of the second pipe 63 having the male screw 64 engraved on the outer surface. Thus, the cap nut 20 can be used as a pipe connection part for connecting the first pipe 60 and the second pipe 63 to each other. The through hole 24 in the bottom 21 of the cap nut 20 may be drilled by one press machine that performs the series of press processes described above, or may be drilled by a separate press machine, You may drill by a separate cutting process. Here, in the aspect of drilling by one press machine that performs the series of press processes described above, the press machine drills the through holes 24 in the metal material 10 in addition to the series of press processes described above. The punching process of the through-hole drilling process is also performed, and a through-hole drilling stage provided with a press die (punching mold) used in the through-hole drilling process is provided.

  When the outer shape of the cap nut 20 is a non-circular shape, such as a shape having the tool hooking surface 23, a substantially similar appearance that is slightly larger than the final outer shape of the cap nut 20 in the cup forming step. The disk-shaped metal material 10 is press-molded into a cup shape so as to have a shape, and the cup-shaped metal material 10 can be plastically deformed substantially uniformly over the entire circumference in the female screw forming step. May be.

  As mentioned above, although the example of the manufacturing method of the cap nut which concerns on this invention was demonstrated, the manufacturing method of the cap nut which concerns on this invention is not restricted to the above-mentioned example.

  For example, the above-described series of press processing is performed by a single press processing machine to produce a cap nut, and individual press processing of the cup forming process and the internal thread forming process is performed by an individual press processing machine. Cap nuts may be manufactured. In addition, the cup forming process is not limited to pressing a disk-shaped metal material into a cup shape by a single press process, but a disk-shaped metal material is gradually formed by a plurality of press processes of two or more times. It is good also as forming the cup-shaped metal raw material which made the plastic deformation and exhibited the external appearance shape which can be thrown into the internal thread formation process.

  In addition, in the first punching process in a series of press work, not only is the rolled material punched to form a flat and disc-shaped metal material, but a flat and disc-shaped metal material is formed by casting or forging. It may be formed. Further, the female screw is not limited to a taper screw, and may be a straight screw such as a metric screw. The screw may be a coarse screw or a fine screw, but is preferably a fine screw. This is because the fine screw has a smaller screw pitch and a lower thread height than the coarse screw, and is easy to press-mold.

It is process drawing which shows an example of the manufacturing method of the cap nut which concerns on this invention. It is drawing which shows another example of a cap nut, (a) is a top view, (b) is a front view, (c) is AA sectional drawing of (b). It is a front view which shows an example of use of a cap nut. It is a front view which shows another example of use of a cap nut.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Metal material 20 Cap nut 21 Bottom part 22 Female screw 23 Tool hooking surface 24 Through-hole 30 Die type 31 Punch type 40 Die type 41 Punch type 42 Screw type 50 Piping 51 Male screw 52 Packing 60 First piping 61 Flange 62 Packing 63 Second piping 64 Male thread

Claims (3)

A cup forming step of pressing a flat metal material into a cup shape;
A female screw imitating the screw mold by press-fitting the metal material molded in a cup shape in the cup forming process onto the screw mold to reduce the outer diameter and extend the entire length. An internal thread forming step for forming a cap nut formed on the inner surface;
A screw nut manufacturing method comprising: a screw mold removing step of rotating the screw die to remove the screw die from the cap nut formed in the female screw forming step. The method of manufacturing a cap nut according to claim 1, wherein the metal material is a copper alloy. The method for manufacturing a cap nut according to claim 1, wherein the female screw is a taper screw.

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