JP2009068641A - Tapered screw for tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tapered screw for a tube capable of prevent the occurrence of seizing even if there is a relatively small burr left after burr removing work. <P>SOLUTION: In Fig. (a), a state that a screw at the tip of a tapered male screw 10 for a tube is subjected to cutting work to reduce the diameter thereof (a part marked out in black) as shown by a reference sign (i) is shown. Fig. (b) shows a screwed and fastened state between a tapered female screw 12 for a tube and the tapered male screw for a tube shown in Fig. (a), and a space is formed between the screw at the tip of the male screw reduced in diameter and the female screw facing it. Fig. (c) shows the case that an axial position of the thread at the tip of the tapered male screw for a tube is changed, and Fig. (d) shows a screwed and fastened state at that time. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pipe taper screw, and more particularly to a pipe taper screw having a function of preventing seizure due to burrs.

  When a pipe taper screw is machined, if the screw shape of the female screw or male screw tip portion becomes an acute angle, burrs are likely to appear, dents are easily formed, and the sealing agent may be peeled off. For this purpose, as shown in FIGS. 4A and 4B, the tip end portions a and b of the pipe taper male screw 10 and the female screw 12 are chamfered. During the chamfering process, as shown in FIGS. 3C and 3D, burrs c and d are generated. Further, as shown by e and f in the chamfered portion, an acute angle portion is generated, so that the acute angle portion may be deformed even with a small force.

When the pipe taper screw in such a state is fastened, burrs or the like generated during chamfering enter between the thread surfaces, and as shown in FIG. Seizure occurs. (Kaziri)
Therefore, deburring with a brush or buff after threading is possible, but depending on the material such as stainless steel. It may not be able to be removed completely, and screw seizure may occur at the time of fastening.

On the other hand, joint parts having tapered pipe threads are formed at both ends of the outer peripheral surface of a seamless steel pipe used for excavating an oil well or pumping out oil from the oil well. A threading method for preventing the generation of burrs in the threading of the pipe taper screw has been proposed. For example, in a pipe end outer peripheral surface threading method in which a taper screw is threaded on the outer peripheral surface of the pipe end and the outer surface of the final end of the pipe end is chamfered, after the taper screw is threaded on the outer peripheral surface of the pipe end, The outer surface of the final end of the tube end is chamfered toward the end direction. In this pipe end outer peripheral threading method, after the taper screw is threaded on the outer peripheral surface of the pipe end, the outer surface of the final end of the pipe end is chamfered so that incomplete threads are not formed during threading. , Burr does not occur. (Patent Document 1)
However, the method disclosed in Patent Document 1 is directed to a pipe taper screw for connecting a steel pipe at both ends of an outer peripheral surface of a seamless steel pipe used for excavating an oil well or pumping oil from the oil well. Compared to a pipe taper screw used for equipment, the shape is large, so that the spatial constraints on the processing blade are relatively loose. Moreover, in patent document 1, there is no description about the process of a taper female screw.

Japanese Patent Laid-Open No. 05-269692

  Even after deburring with a brush, buff, etc. after threading, depending on the material, such as stainless steel, the burr may not be removed completely and seizure may occur.

  As a result of diligent research, examination, and trial manufacture, the inventor of the present application has conducted deburring with a brush, buff, etc. infinitely when manufacturing a taper screw for a pipe. In order to solve the problem of relatively small burrs that remain after deburring work that has been performed in the past, a gap is formed between the opposing threads at the tip of the tapered male screw and the tapered female screw. As a result, it has been found that the above problem can be basically solved.

  Accordingly, an object of the present invention is to provide a pipe taper screw that does not cause seizure even if there is a relatively small burr remaining after a deburring operation to the extent conventionally performed after chamfering.

In order to achieve the above object, a taper screw for a pipe according to the present invention comprises:
A gap is formed between the screws facing each other at a tip portion of the male and female pair of taper screws for pipes in a screwed and tightened state.
In that case, the said clearance gap can be comprised by making small the screw diameter of the front-end | tip part of the taper male screw for pipes.
Further, in that case, the gap can be configured by changing the screw thread position of the tip portion of the pipe male tape screw.
In this case, the gap can be configured by changing the screw taper angle of the tip portion of the taper male screw for pipe.
In this case, the gap can be formed by increasing the effective screw diameter of the tip portion of the pipe taper female screw.
Furthermore, in that case, the gap can be configured by changing the screw position of the tip portion of the taper female screw for pipe.
Further, in that case, the gap can be configured by changing the angle of the thread of the tip portion of the pipe taper female screw.
Furthermore, the said clearance gap can be comprised by combining two or more said each structure.

According to the pipe taper of the present invention,
Since a gap is formed between the screws facing each other in the screwed and tightened state of the male and female pipe taper screws, the deburring is not performed completely, and the screw tip part If a small burr remains on the surface, even if the burr enters the gap, the surface pressure between the screw and the burr does not increase, and therefore, the screw does not seize at the time of fastening.

  FIG. 1 is an example based on an embodiment of the present invention, in which (a) is an enlarged view of a cross-sectional shape processed so as to reduce the screw diameter of the tip of the tapered male screw for a pipe, (b). Shows the cross-sectional shape of the threaded and tightened state of the pipe taper female screw by normal processing and the pipe taper male screw shown in (a), and (c) shows partial processing on the tip of the pipe taper male screw. (D) is a figure which shows the cross-sectional shape of the screwing and clamping | tightening state of the taper female screw for pipes by a normal process, and the taper male screw for pipes shown by (c).

In FIG. 1A, the threaded portion of the tip portion (left side of the drawing) of the pipe taper male screw 10 has a small diameter over a screw range of about 2 pitches as indicated by reference symbol i in the drawing. The state of deletion processing (the blacked out portion) is shown.
FIG. 1 (b) shows the screwed / tightened state of the pipe taper female screw 12 by normal taper screw processing and the pipe taper male screw 10 shown in FIG. 1 (a). As shown by a reference symbol j, a gap is formed between the screw portion of the tip portion 10 and the screw portion of the female screw 12 facing the tip portion.
FIG.1 (c) shows deleting one side part of the thread shown with the referential mark k so that the axial direction position of the thread of the front-end | tip part of the taper male screw for pipes may be changed.
FIG. 1 (d) shows the screwed / tightened state of the pipe taper female screw 12 by normal taper thread processing and the pipe taper male screw 10 shown in FIG. This indicates that a gap is formed between the screw portion at the tip of the male screw 10 that has been replaced and the screw portion of the female screw 12 facing the male screw 10 as indicated by reference numeral 1.

FIG. 2 shows another embodiment in which a gap is formed in the tip portion of the pipe taper male screw and the female screw. FIG. 2A shows the tip portion of the pipe taper male screw 10 as indicated by reference numeral m. Perform taper angle. That is, an angle forming process of an angle m2 degrees is performed with respect to an angle m1 degrees by a normal taper screw process. FIG. 4B shows the screwed / tightened state of the pipe taper female screw 12 by the normal taper thread processing and the pipe taper male screw 10 shown in FIG. In addition, a gap is formed between the screw portion at the tip of the male screw 10 and the screw portion of the female screw 12 facing the male screw 10 as indicated by reference numeral n.
FIG. 2 (c) is a diagram showing a cross-sectional shape of the distal end portion of the pipe taper female screw 12 that has been subjected to deletion processing (black-filled portion) in order to increase the screw diameter, as indicated by the reference symbol o. These are the figure which shows the cross-sectional shape of the screwing and clamping | tightening state of the taper male screw 10 for pipes by the normal taper screw processing, and the taper female screw 12 for pipes processed by the large diameter shown by the same figure (c).

  FIG. 3 shows still another embodiment in which a gap is formed at the distal end portions of the pipe taper male and female screws. FIGS. 3 (a) and (b) correspond to FIGS. 1 (c) and 1 (d). FIGS. 2C and 2D correspond to FIGS. 2A and 2B, and the difference is that the deleted portion to be removed is formed on the side of the taper female screw 12 for the tube. That is, in FIG. 9A, as indicated by the reference symbol q, a part of the tip of the pipe taper female screw 12 (right side in the figure) is deleted so as to change the axial position of the thread. As a result, as shown in FIG. 4B, in the screwed / tightened state between the pipe taper male screw 10 obtained by normal taper thread processing and the pipe taper female screw 12 shown in FIG. The gap shown is formed.

  Moreover, in the same figure (c), a taper angle | corner is given to the front-end | tip part of the taper female screw 12 for pipes as shown with the referential mark s. That is, as shown in the figure, an angle forming process of an angle s2 degrees is performed with respect to an angle s1 degrees by a normal taper screw process. FIG. 4D shows the screwed / tightened state of the pipe taper male screw 10 by normal taper thread processing and the pipe taper female screw 12 shown in FIG. As shown by the reference symbol t, a gap is formed between the thread portion of the distal end of the pipe taper female screw 12 and the thread portion of the pipe taper male screw 10 facing it.

  In each of the above-described embodiments, either one of the threaded male part 10 for pipe and the female threaded taper 12 for pipe is removed by the deletion process. However, the thread part on the other side may be further deleted. Is possible.

  The preferred embodiments of the present invention have been described above. However, those skilled in the art can make various modifications based on these embodiments.

It is an Example based on embodiment of this invention, Comprising: (a) is a figure which shows the cross-sectional shape which gave the screw diameter of the front-end | tip part of the taper male screw for pipes, (b) is a normal taper The figure which shows the cross-sectional shape of the screwing | tightening state of the taper male screw for pipes by a screw process, and the taper male screw for pipes shown by (a), (c) has performed the partial process to the front-end | tip part of the taper male screw for pipes The figure which shows a cross-sectional shape, (d) is a figure which shows the cross-sectional shape of the screwing and fastening state of the taper female screw for pipes by normal processing, and the taper male screw for pipes shown by (c). It is another Example which forms a clearance gap in the front-end | tip part of the taper male male and female screw, (a) shows the example which performed the taper angle to the front-end | tip part of the taper male screw for pipes, (b) is the figure. The figure which shows the screwing and fastening state of the taper female screw for pipes by the normal taper thread processing, and the taper male screw for pipes shown in (a), (c) is a screw diameter in the tip part of the taper female screw for pipes. The figure which shows the cross-sectional shape which gave the deletion process to enlarge, (d) is a screw of the taper male screw for pipes by the usual taper thread processing, and the taper female screw for pipes processed in large diameter shown in the figure (c) It is a figure which shows the cross-sectional shape of a fitting and fastening state. Still another embodiment in which a gap is formed at the distal end portion of the taper male and female screws for pipes. FIGS. (A) and (b) correspond to FIGS. 1 (c) and (d), and FIG. (c), (d) is a figure corresponding to Drawing 2 (a), (b), and is a figure showing the section shape where each deletion part is formed in the taper female screw side for pipes. It is a screw sectional view for explaining a state of chamfering processing of a taper male screw for a pipe and a female screw used for the conventional line, (a) is a taper male screw tip for a pipe, and (b) is a pipe. (C) is an enlarged view of a portion of (a), and (d) is an enlarged view of b portion of (b). It is sectional drawing which shows the state from which the burr | flash etc. which generate | occur | produced at the time of chamfering entered between screw surfaces.

Explanation of symbols

10 Taper male screw for pipe 12 Taper female screw for pipe a Tip part b Tip part c Burr d Burr e Sharp angle f Sharp angle g Rigid place h Rigid place i Deleted part j Clearance k Deleted part (angling)
l Clearance m Deletion part (angling)
n Clearance o Deleted portion p Clearance q Deleted portion r Clearance s Deleted portion t Clearance

Claims (8)

  A taper screw for a pipe, wherein a gap is formed between the opposing threads at the tip of the screw in a screwed and tightened state of a pair of male and female pipe taper screws.   The said clearance gap is formed by reducing the screw diameter of the front-end | tip part of the taper male screw for pipes, The taper screw for pipes described in Claim 1 characterized by the above-mentioned.   The said clearance gap is formed by changing the screw thread position of the front-end | tip part of the taper male screw for pipes, The taper screw for pipes described in Claim 1 characterized by the above-mentioned.   2. The pipe taper screw according to claim 1, wherein the gap is formed by changing a screw taper angle of a tip portion of the pipe taper male screw.   2. The pipe taper screw according to claim 1, wherein the gap is formed by increasing a screw effective diameter of a tip portion of the pipe taper female screw.   2. The tube taper screw according to claim 1, wherein the gap is formed by changing a screw position of a tip portion of the tube taper female screw.   2. The pipe taper screw according to claim 1, wherein the gap is formed by changing an angle of a thread of a tip portion of the pipe taper female screw.   The gap is formed by a combination of the gap specified in any one of claims 1 to 7 and the gap specified in any other one of claims 1 to 7. The taper screw for pipes according to claim 1.

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