JP2009180360A - Tapered screw member and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tapered screw member for securing the area of the end face of a tapered portion for improved sealing performance while holding the strength of the end of the tapered portion, and to provide its manufacturing method for easily machining a screw while uniformly holding the thickness of the tapered portion. <P>SOLUTION: The tapered screw member is manufactured which has a male screw formed on the outer peripheral face of a tapered member having the tapered portion at the end. In this case, pressing or cutting work is applied to the end of a metal cylinder body 14 to produce the tapered member having the tapered portion 12 tapered with its diameter gradually shrunk toward the end side and its thickness uniform. Then, the male screw is machined on the outer peripheral face of the tapered portion 12 of the obtained tapered member to manufacture the tapered screw member. The angle of inclination of the tapered portion 12 is preferably 1-3°. The male screw is preferably machined with rolling work. The cylinder body 14 is preferably formed of stainless steel. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a taper screw member as a joint used when connecting pipes, for example, and a manufacturing method thereof.

  Conventionally, a stainless steel joint is used as a joint for connecting a water supply pipe or a hot water supply pipe. When a screw is screwed into this stainless steel joint, it is generally performed by rolling. As shown in FIG. 5, when the joint is a taper screw 31, both ends of the cylindrical body 32 are subjected to a rolling process so that both ends of the cylindrical body 32 have tapered male threads. 33 is formed. The taper screw 31 has a drawback in that the outer peripheral surface of the end portion is reduced in diameter by rolling, so that the thickness 34 of the end portion becomes thin (for example, 1 mm). In that case, the area of the end face of the taper screw 31 is reduced, which may result in a decrease in the sealing effect by packing or a decrease in the strength of the end.

In order to eliminate such drawbacks, it is necessary to make the wall thickness 34 of the taper screw 31 excessively thick in advance. As a result, the taper screw 31 becomes heavy, the material is wasted, and the manufacturing cost is increased. There was a problem that it became bulky. In view of this, a method of forming an internal thread by swaging (swaging) has been proposed (see, for example, Patent Document 1). That is, this method is a method for manufacturing a metal socket in which the end of a stainless steel welded tube formed into a cylindrical shape is reduced in diameter and thickened by swaging and a female screw is formed in the thickened portion.
JP 2007-265979 A (second page and third page)

  However, the metal socket manufacturing method described in Patent Document 1 has a tendency that the surface of the metal socket is hardened because the diameter is reduced and the wall thickness is increased by swaging. Therefore, there has been a problem that it is very difficult to screw a screw after swaging the end of the welded pipe.

  Accordingly, an object of the present invention is to provide a taper screw that can secure the area of the end surface of the taper portion, improve the sealing performance by packing, and maintain the strength of the end portion of the taper portion. It is to provide a member. It is another object of the present invention to provide a method of manufacturing a taper screw member that can easily process a screw and can keep the thickness of the taper portion uniform.

  In order to achieve the above object, the taper screw member of the invention according to claim 1 has a tapered portion at an end portion, a male screw is formed on the outer peripheral surface of the tapered portion, and the thickness of the tapered portion is increased. It is characterized by being uniformly formed.

  A taper screw member manufacturing method according to a second aspect of the present invention is the taper screw member manufacturing method according to the first aspect. Then, after pressing the end portion of the metal cylindrical body to form a taper shape having a diameter that is reduced toward the end side and forming a taper portion having a uniform thickness, the taper portion of the taper member A male screw is machined on the outer peripheral surface of this.

According to a third aspect of the present invention, there is provided the taper screw member manufacturing method according to the second aspect, wherein an inclination angle of the tapered portion is 1 to 3 °.
According to a fourth aspect of the present invention, there is provided the taper screw member manufacturing method according to the second or third aspect, wherein the male thread is processed by rolling or cutting.

According to a fifth aspect of the present invention, there is provided a taper screw member manufacturing method according to any one of the second to fourth aspects, wherein the cylindrical body is made of stainless steel.
According to a sixth aspect of the present invention, there is provided a taper screw member manufacturing method according to any one of the second to fifth aspects, wherein the tapered member has tapered portions at both ends.

  In the taper screw member according to the first aspect, the end portion has a taper portion, the male screw is formed on the outer peripheral surface of the taper portion, and the thickness of the taper portion is formed uniformly. For this reason, the area of the end surface of the taper portion can be ensured, the sealing performance by packing can be improved, and the strength of the end portion of the taper portion can be maintained.

  In the taper screw member manufacturing method according to claim 2, the end of the metal cylindrical body is pressed or cut to form a taper that is reduced in diameter toward the end, and the taper having a uniform thickness is formed. After producing the taper member which has, a male screw is processed to the outer peripheral surface of the taper part of this taper member. For this reason, the thickness of the taper portion of the taper member is uniform, and in this state, a male screw is formed on the outer peripheral surface of the taper portion, and the thickness of the taper portion is kept uniform. Therefore, according to the manufacturing method of the present invention, it is possible to easily process the screw and to keep the thickness of the tapered portion uniform.

  In the invention according to claim 3, since the inclination angle of the taper portion is 1 to 3 °, in addition to the effect of the invention according to claim 2, it is easy to keep the thickness of the taper portion uniform. At the same time, it is useful because it can meet the standards for taper threads for pipes.

  In the invention according to claim 4, since the processing of the male screw is by rolling, in addition to the effect of the invention according to claim 2 or 3, the male screw is formed along the inclination angle of the taper portion. Thus, a male screw can be easily threaded on the outer peripheral surface of the tapered portion while keeping the thickness of the tapered portion uniform.

  In the invention according to claim 5, since the cylindrical body is formed of stainless steel, in addition to the effects of the invention according to any one of claims 2 to 4, the strength at the tapered portion is increased and rust is generated. Can be suppressed, and durability can be improved.

  In the invention according to claim 6, since the taper member has the taper portions at both ends, in addition to the effect of the invention according to any one of claims 2 to 5, the same method as the method of processing the taper portion at one end. The taper portion at the other end can be processed by the processing method, and a taper member having taper portions at both ends can be easily manufactured.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments that are considered to be the best of the present invention will be described in detail with reference to the drawings.
As shown in FIG. 4, the taper screw member 10 of the present embodiment is provided with taper portions 12 at both ends of the taper member 11, and male threads (external threads) 13 are formed on the outer peripheral surface of the taper portion 12. It is configured. The taper portion 12 is uniformly formed with a thickness 25 of, for example, 2.5 mm. Further, the taper inclination angle α of the taper portion 12 is preferably 1 to 3 °, for example, 1.8 °. By setting the taper inclination angle α in such a range, it is easy to maintain the thickness 25 of the taper portion 12 uniformly, and at the same time, it is possible to satisfy the standard of the taper screw for pipes, which is useful. . When the inclination angle α is smaller than 1 °, the meaning as a taper screw is reduced, and when it is larger than 3 °, it is difficult to process the tapered portion 12 and it is difficult to form the thickness 25 of the tapered portion 12 uniformly. Show the trend.

Next, the manufacturing method of such a taper screw member 10 is demonstrated.
The taper screw member 10 is manufactured through the following first step and second step. In the first step, the end portion of the metal cylindrical body 14 is pressed to form a taper shape with a diameter that decreases toward the end portion, and the taper member 11 having the taper portion 12 with a uniform thickness 25 is produced. In the second step, the male screw 13 is processed on the outer peripheral surface of the tapered portion 12 of the tapered member 11 obtained in the first step. In the first step, press working is employed, and the press working will be specifically described.

  FIG. 1A is a cross-sectional view schematically showing a main part of a press machine. As shown in the figure, a press jig 15 is arranged at the lower part and a receiving jig 16 is arranged at the upper part. Is done. Although the press jig 15 has a disk shape as a whole, it is divided into eight split molds 17 having the same shape that form a flat fan shape, and is configured to be able to expand and contract in the radial direction. Each split mold 17 is formed with a notch on the upper inner side, and is inclined so as to spread obliquely outward from the mounting surface 18 on which the cylindrical body 14 is mounted and the outer peripheral edge of the mounting surface 18. An inclined surface 19 is provided. The receiving jig 16 is fixedly disposed at an upper position of the pressing jig 15 and has a sliding contact surface 20 that is inclined so that its inner end surface expands downward. The pressing jig 15 is configured to be raised by hydraulic pressure, and the sliding surface 21 on the outer periphery of each split mold 17 is brought into sliding contact with the sliding contact surface 20 at the end of the receiving jig 16 along with the rising. The mold 17 gradually moves toward the center.

  Then, with the cylindrical body 14 placed on the placement surface 18 of the press jig 15, the press jig 15 is raised to receive the sliding surface 21 of the press jig 15 and the sliding surface of the jig 16. 20 in sliding contact. Thereby, each divided mold 17 is moved in the center direction, and the outer peripheral surface of the lower end portion of the cylindrical body 14 is formed into a taper shape by the inclined surface 19 of each divided mold 17, thereby forming the tapered portion 12.

  Subsequently, a rolling process or a cutting process is employed as a method of processing the external thread 13 on the outer peripheral surface of the tapered portion 12 in the second step. The case of the rolling process will be described. FIG. 2A is a cross-sectional view schematically showing a main part of the rolling jig. As shown in the figure, the supporting jig 22 having an inverted T-shaped cross section is obtained in the first step. The taper member 11 is externally fitted. In this state, a rolling jig (rolling die) 23 is disposed at a position facing the outer periphery of the tapered portion 12 of the tapered member 11. An inner peripheral surface of the rolling jig 23 is formed in a slanted shape whose diameter is reduced toward the lower side, and a male screw forming portion 24 having a corrugated cross section for forming the male screw 13 is provided. The inclination angle α of the inner peripheral surface of the rolling jig 23 is set to be the same as the inclination angle α of the taper portion 12 of the taper member 11. The rolling jig 23 is configured to be rotatable and configured to be able to expand and contract.

  In the state where the taper member 11 is supported by the support jig 22, the diameter of the rolling jig 23 is reduced while rotating, whereby the male screw 13 is inclined on the outer peripheral surface of the taper part 12 of the taper member 11, and the taper part 12 is inclined. It can be engraved along.

Next, the effect | action of the manufacturing method of the taper screw member 10 is demonstrated.
When manufacturing the taper screw member 10 having a taper screw at both ends thereof from the cylindrical body 14 made of stainless steel, first, the cylindrical body 14 is mounted on the press jig 15 as shown in FIG. Place on the mounting surface 18. Subsequently, as shown in FIG. 1B, when the press jig 15 is raised by hydraulic pressure, the upper end portion of each split mold 17 reaches a position near the lower end portion of the receiving jig 16. Next, as shown in FIG. 1C, when the pressing jig 15 is further raised, the sliding surface 21 on the outer periphery of each split mold 17 comes into sliding contact with the sliding contact surface 20 of the receiving jig 16.

  At this time, since the position of the receiving jig 16 is fixed, each split mold 17 of the press jig 15 moves toward the center, and the inclined surface 19 of the split mold 17 is the outer peripheral surface of the lower end portion of the cylindrical body 14. Is pressed. Accordingly, as shown in FIG. 1 (d), the lower end portion of the cylindrical body 14 is formed in a tapered shape along the inclined surface 19 of the split mold 17, and the tapered portion 12 is obtained.

  Thereafter, the split die 17 of the pressing jig 15 is opened to take out the cylindrical body 14, and the end portion on which the tapered portion 12 is not formed with the cylindrical body 14 taken out upside down is placed on the mounting surface of the split die 17. 18 is mounted. Thereafter, the same operation as described above is repeated, and the taper portion 12 having the taper portions 12 at both ends is obtained by forming the taper portions 12 at the end portions not formed in the taper shape.

  Next, as shown in FIG. 2A, the taper member 11 having the taper portions 12 at both ends is externally fitted to and supported by the support jig 22. In this state, as shown in FIG. 2B, the outer peripheral surface of the taper portion 12 of the taper member 11 is produced by rolling the outer peripheral surface of the taper portion 12 by reducing the diameter while rotating the rolling jig 23. A male screw 13 is screwed into the screw. In this case, the outer peripheral area of the taper portion 12 is plastically deformed by applying a pressure exceeding the yield point of stainless steel to the taper portion 12 of the taper member 11. That is, in the taper portion 12 of the taper member 11 shown enlarged in FIG. 3A, as shown in FIG. 3B, the inside of the rolling jig 23 having the same inclination angle α along the taper surface. By rolling the peripheral surface, the flesh of the screw valley escapes and a mountain is formed, so that the male screw 13 is formed while the wall thickness 25 is kept constant. In addition, the dashed-two dotted line in FIG.3 (b) has shown the position of the taper part 12 surface before a rolling process. In this way, the male screw 13 is screwed into one taper portion 12 of the taper member 11.

  Next, the rolling jig 23 is expanded and separated from the taper member 11, and the taper member 11 is taken out. The taper portion 12 on which the male screw 13 is not formed is externally fitted to the support jig 22. Then, the male screw 13 is formed on the outer periphery of the tapered portion 12 by operating in the same manner as described above. By such an operation, as shown in FIG. 4, the male screw 13 can be formed on the tapered portions 12 at both ends of the tapered member 11, and the tapered screw member 10 is manufactured.

The effects exhibited by the above embodiment will be described collectively below.
In the taper screw member 10 in the embodiment, the end portion has the taper portion 12, the male screw 13 is formed on the outer peripheral surface of the taper portion 12, and the thickness of the taper portion 12 is formed uniformly. For this reason, the area of the end surface of the taper part 12 can be ensured, the sealing performance by packing can be improved, and the strength of the end part of the taper part 12 can be maintained.

  In the method for manufacturing the taper screw member 10 in the embodiment, after the end portion of the cylindrical body 14 is pressed to produce the taper member 11 having the uniform taper portion 12 with the thickness 25, the outer periphery of the taper portion 12 is The male screw 13 is processed on the surface. For this reason, the taper member 11 has a uniform thickness 25 of the taper portion 12. In this state, the male screw 13 is formed on the outer peripheral surface of the taper portion 12, and the thickness 25 of the taper portion 12 is uniformly maintained.

  Therefore, according to this embodiment, since the material is not hardened compared to the conventional swaging process, the male screw 13 can be easily processed, the processing time can be shortened, and the thickness of the taper portion 12 can be reduced. The thickness 25 can be kept uniform. As a result, the area of the end face of the taper portion 12 in the taper screw member 10 can be sufficiently ensured, and the sealing performance when sealed with the end face using packing can be improved. The strength at the end can be increased. In addition, unlike the conventional swaging process, it is not necessary to previously form the thick wall 34 so that the material can be saved and the manufacturing cost can be reduced.

  -Since the inclination angle α of the taper portion 12 of the taper member 11 is 1 to 3 °, it is easy to keep the wall thickness 25 of the taper portion 12 uniform, and the standard of the taper screw for the pipe is satisfied. Can and is useful.

  Since the processing of the male screw 13 is based on rolling, the male screw 13 can be formed along the inclination angle α of the tapered portion 12, and the taper portion 12 can be tapered while keeping the wall thickness 25 uniform. The external thread 13 can be easily threaded on the outer peripheral surface of the portion 12.

-Since the cylindrical body 14 is formed of stainless steel, the strength in the tapered portion 12 can be increased, the occurrence of rust can be suppressed, and the durability can be improved.
-Since the taper member 11 has the taper part 12 at both ends, the taper part 12 at the other end can be processed by the same processing method as the method of processing the taper part 12 at one end. The taper member 11 having the taper portion 12 can be manufactured.

In addition, this embodiment can also be changed and embodied as follows.
-As a method of processing the external thread 13 in the outer peripheral surface of the taper part 12 of the taper member 11, methods, such as cutting, are employable. Processing such as cutting is performed according to a conventional method for forming a taper screw.

The taper screw member 10 may have a structure in which the male screw 13 is formed only at one end of the taper member 11.
-The number of divisions of the press jig 15 can be set to an arbitrary number of divisions such as six or ten.

The male screw 13 of the taper portion 12 can be arbitrarily set by changing the rolling jig 23 with respect to the pitch, the depth of the trough (the height of the crest), and the like.
-As a material of the cylindrical body 14, metals, such as copper alloy and nickel other than stainless steel, can also be used.

  In the above embodiment, the pressing jig 15 is fixed and the pressing jig 15 is raised in the press working. However, the receiving jig 16 is lowered and the sliding contact surface 20 of the pressing jig 15 is lowered. The press jig 15 may be moved to the center side by sliding on the sliding surface 21.

Further, the technical idea that can be grasped from the embodiment will be described below.
The press work is performed so that the inner peripheral surface is pressed from the outer periphery of the end portion of the metal cylindrical body toward the center by a press jig configured by a split die having a tapered inner peripheral surface. The method for manufacturing a tapered screw member according to any one of claims 2 to 6. In this case, in addition to the effect of the invention according to any one of claims 2 to 6, it is possible to easily process the tapered portion at the end portion of the cylindrical body by pressing so that the thickness is constant. it can.

  The rolling process is performed so as to roll on the taper portion of the taper member by a rolling jig constituted by a male screw forming portion having the same inclination angle as the taper portion of the taper member. The method for manufacturing a taper screw member according to any one of claims 4 to 6, wherein the taper screw member is manufactured. In this case, in addition to the effect of the invention according to any one of claims 4 to 6, the male screw can be easily processed while the thickness of the taper portion of the taper member is kept constant by the rolling jig. can do.

It is sectional drawing which shows the manufacturing process of the taper screw member in embodiment, (a) is sectional drawing which shows the state which mounted the cylindrical body on the mounting surface of a press jig, (b) is the state of (a) (C) is a sectional view showing a state where the press jig is further raised from the state of (b), and (d) is a taper portion at one end of the cylindrical body. Sectional drawing which shows the provided taper member. (A) is sectional drawing which shows the state which supported the taper member which has a taper part on both ends on a support jig, (b) is a taper by rotating a rolling jig from the state of (a), reducing a diameter. Sectional drawing which shows the state which forms a male screw in a part. (A) is a partial expanded sectional view which shows the taper part of a taper member, (b) is a partial expanded sectional view which shows the state which formed the external thread in the outer peripheral surface of a taper part. Sectional drawing which shows the taper screw member of this invention. Sectional drawing which shows the conventional taper screw member.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Tapered screw member, 11 ... Tapered member, 12 ... Tapered part, 13 ... Male screw, 14 ... Cylindrical body, 25 ... Thickness, (alpha) ... Angle of inclination.

Claims (6)

A taper screw member having a taper portion at an end, a male screw formed on an outer peripheral surface of the taper portion, and a thickness of the taper portion being uniformly formed. It is a manufacturing method of the taper screw member according to claim 1,
After the end of the metal cylinder is pressed to form a taper that has a diameter that is reduced toward the end, and a tapered member having a uniform thickness is produced, the outer periphery of the taper of the taper A method of manufacturing a taper screw member, wherein a male screw is processed on a surface. The method for manufacturing a taper screw member according to claim 2, wherein an inclination angle of the taper portion is 1 to 3 °. The method of manufacturing a taper screw member according to claim 2 or 3, wherein the processing of the male screw is performed by rolling or cutting. The method for manufacturing a tapered screw member according to any one of claims 2 to 4, wherein the cylindrical body is made of stainless steel. The taper screw member manufacturing method according to any one of claims 2 to 5, wherein the taper member has tapered portions at both ends.

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