JPH11315976A - Pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the leakage of high pressure fluids through a press-contact surface even if a pipe material and a nipple are frequently detached. SOLUTION: A pipe joint 20 is provided with a pipe material having a truncated conical seat part 25 formed in its tip, and a nipple 22 having a conical hole- shaped seat surface 31 formed in its inner surface, which corresponds to the seat part 25 of the pipe material 21. The length of the generating line of the truncated cone of the seat part 25 of the pipe material 21 is longer than that of the generating line of the conical hole of the seat surface 31 of the nipple 22, and during tight adhesion between the pipe material 21 and the nipple 22, the tip 27 of the seat part 25 of the pipe material 21 is protruded toward the inner deep side more than the seat surface 31 of the nipple 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint, and more particularly, to a high-pressure fitting type pipe joint used for automobiles and the like.

[0002]

2. Description of the Related Art A conventional fitting type pipe fitting is shown in FIG.
The following are known. The pipe joint 1 includes a pipe member 2, a nipple 3, a sleeve 4, and a nut 5.

[0003] The tube member 2 has a projection 7 having a truncated cone-shaped enlarged seat 6 formed on the outer peripheral surface of one end by pressing or the like. The diameter of the seat portion 6 is reduced toward the distal end portion 8, and the large-diameter portion 9 is larger in diameter than the outer diameter of the tube 2.
The small diameter portion 10 has a larger diameter than the inner diameter of the tube 2.

The nipple 3 is formed on the inner peripheral surface at one end of the cylindrical portion 11 in a direction in which a conical hole-shaped seating surface 12 corresponding to the seating portion 6 of the pipe member 2 expands in diameter toward the end of the cylindrical portion 11. Have been. The large diameter portion 13 of the seating surface 12 is
The smaller diameter portion 14 is formed to have the same diameter as the inner diameter of the tube 2. A male screw 15 is formed on the outer peripheral surface of the cylindrical portion 11.

[0005] The sleeve has a cylindrical shape and an inner diameter of the tube 2.
The flange 16 is formed at one end with a diameter larger than that of the projection 7 of the pipe member 2 and in contact with the axial side surface of the projection 7.

The nut 5 has an inner diameter at one end slightly larger than an outer diameter of the sleeve 4, and an inner axial side surface thereof abuts a flange 16 of the sleeve 4.
On the inner peripheral surface at the other end, a female screw 17 that is screwed with the male screw 15 of the nipple 3 is formed.

[0007] Since the conventional pipe joint 1 is configured as described above, the flange 16 of the sleeve 4 is directed toward the protruding portion 7 and the female screw 17 of the nut 5 is connected to the protruding portion 7 of the pipe 2.
Insert as side. When the female screw 17 of the nut 5 is screwed into the external thread 15 of the nipple 3 and the nut 5 is tightened to the nipple 3, the truncated cone shape of the seat 6 of the pipe 2 and the conical hole shape of the seat surface 12 of the nipple 3 are formed. The pipe joint 1 is assembled in close contact with the fluid, and the fluid is sent through the pipe 2 to the required equipment through the nipple 3.

[0008]

By the way, it is very difficult to form the front end 8 of the seat 6 of the pipe 2 into a perfect circle in the above-mentioned conventional pipe joint 1. When the pipe joint 1 is assembled, as shown in FIG. 4, the tip 8, for which it is difficult to ensure accuracy, comes into contact with the seating surface 12 of the nipple 3 and tightens the nut 5 with respect to the nipple 3. As a result, a part of the distal end portion 8 is not a perfect circle, so that it comes into close contact with the seat surface 12 in such a manner as to bite it. Therefore, at first, there is no leakage of fluid between the seat portion 6 and the seat surface 12, but it is difficult to secure the close contact between the seat portion 6 and the seat surface 12 when the fitting 1 is repeatedly attached and detached. Thus, there is a problem that a fluid (especially, a high-pressure gas) leaks from the pipe joint 1 due to the occurrence of a portion that is not completely in close contact.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is an object of the present invention to provide a highly reliable pipe joint which does not leak even if it is attached to and detached from any fluid many times. It was made for the purpose.

[0010]

SUMMARY OF THE INVENTION To solve the above-mentioned conventional problems, a pipe joint according to the present invention comprises a pipe having a truncated cone-shaped seat at an axial end thereof, and a conical hole corresponding to the seat of the pipe. And a nipple formed with an inner surface having a shaped seating surface, wherein a length of a generating line of a truncated cone of the seating portion of the pipe material is formed longer than a length of a generating line of a conical hole of the seating surface of the nipple. When the pipe and the nipple are in close contact with each other, the distal end of the seat of the pipe is configured to protrude further inward than the seat surface of the nipple.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pipe joint according to the present invention will be described below with reference to FIGS. 1 and 2, omitting details of the same parts as those of the prior art.

The pipe joint 20 includes a pipe 21 and a nipple 22.
, A sleeve 23 and a nut 24.

The tubular member 21 is provided on its outer peripheral surface at one end with a projection 26 formed with a truncated cone-shaped enlarged seat portion 25 suitable for press molding or the like. Unlike the conventional example shown in FIG. 3, the projection 26 has a thickness substantially equal to that of the main body of the tubular member 21. Therefore, the annular recess 19 is formed inside the projection 26 in the radial direction. For this reason, the projection 26 can be somewhat flexed as a whole. The seat portion 25 is formed so as to decrease in diameter toward the axial end portion 27, the large diameter portion 28 is larger in diameter than the outer diameter of the tube 21, and the small diameter portion 29 is formed in the tube 21. It is almost equal to the inside diameter.

The nipple 22 has a conical hole-shaped seating surface 3 corresponding to the seating portion 25 of the pipe member 21 on the inner peripheral surface at one end of the cylindrical portion 30.
1 is formed so as to increase in diameter toward the distal end of the cylindrical portion 30. The large diameter portion 32 of the seating surface 31 is
The small diameter portion 33 is formed to be larger in diameter than the small diameter portion 29 of the tube 21. Therefore, the length of the generatrix of the truncated cone of the seat portion 25 is longer than the length of the generatrix of the conical hole of the seat surface 31. The external thread 34 is formed on the outer peripheral surface of the cylindrical portion 30. Note that the sleeve 23 and the nut 24 have the same structure as in the related art, and a description thereof will be omitted.

Since the pipe joint 20 is constructed as described above, the sleeve 23 is inserted into the pipe member 21 and the nut 24 is inserted into the sleeve 23, and the female screw 17 of the nut 24 is screwed into the external thread 34 of the nipple 22. Nut 24
Is tightened to the nipple 22, as shown in FIG. 2, the truncated cone of the seat portion 25 of the pipe member 21 and the seat surface 31 of the nipple 22 are formed.
The pipe joint 20 is assembled in close contact with the conical hole shape. In this case, the distal end portion 27 of the seat portion 25, for which it is difficult to achieve the roundness processing accuracy, is released so as to protrude from the seat surface 31 of the nipple 2 toward the inner side (left side in FIG. 1). Therefore, the distal end portion 27 does not abut against the seating surface 31, and the hermeticity is maintained by the surface contact between the truncated cone shape of the seating portion 25 having a high roundness and the conical hole shape of the seating surface 31. Fluid does not leak from the fitting 20. In addition, due to the annular concave portion 19, the protrusion 26 can be elastically deformed as a whole, and the seat portion 25 is easily adapted to the seat surface 31 and does not twist.

[0016]

As described above, in the pipe joint according to the present invention, a pipe member having a truncated cone-shaped seat at the tip and a conical hole-shaped seating surface corresponding to the seat of the pipe material are formed on the inner surface. In a pipe joint with a nipple, the length of the bus bar of the truncated cone of the seat of the pipe is formed longer than the length of the bus bar of the conical hole of the seat of the nipple, and when the pipe is in close contact with the nipple, Since the front end of the seat protrudes toward the inner rear side from the seat surface of the nipple, close contact between the seat and the seat surface is always maintained, and high-pressure fluid does not leak from the pipe joint.

Also, no matter how many times the pipe material and the nipple are attached and detached many times, the conical shape of the seat portion and the seat surface with good roundness accuracy is not deformed, so that the high-pressure fluid does not leak. Then, it is possible to provide an inexpensive and leak-free pipe joint simply by changing the structure without adding any components.

[Brief description of the drawings]

FIG. 1 is a partial axial sectional view showing an embodiment of a pipe joint according to the present invention.

FIG. 2 is an enlarged view of a seat portion and a seat surface portion of FIG. 1;

FIG. 3 is a partial axial sectional view of a conventional pipe joint.

FIG. 4 is an enlarged view of a seat portion and a seat surface portion of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 19 Annular concave part 20 Pipe joint 21 Pipe material 22 Nipple 23 Sleeve 24 Nut 25 Seat part 27 Tip part 31 Seat surface

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[Procedure amendment]

[Submission date] May 27, 1999

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

[Title of the Invention] Pipe fitting

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint, and more particularly, to a high-pressure fitting type pipe joint used for automobiles and the like.

[0002]

2. Description of the Related Art A conventional fitting type pipe fitting is shown in FIG.
The following are known. The pipe joint 1 includes a pipe member 2, a nipple 3, a sleeve 4, and a nut 5.

[0003] The tube member 2 has a projection 7 having a truncated cone-shaped enlarged seat 6 formed on the outer peripheral surface of one end by pressing or the like. The diameter of the seat portion 6 is reduced toward the distal end portion 8, and the large-diameter portion 9 is larger in diameter than the outer diameter of the tube 2.
The small diameter portion 10 has a larger diameter than the inner diameter of the tube 2.

The nipple 3 is formed on the inner peripheral surface at one end of the cylindrical portion 11 in a direction in which a conical hole-shaped seating surface 12 corresponding to the seating portion 6 of the pipe member 2 expands in diameter toward the end of the cylindrical portion 11. Have been. The large diameter portion 13 of the seating surface 12 is
The smaller diameter portion 14 is formed to have the same diameter as the inner diameter of the tube 2. A male screw 15 is formed on the outer peripheral surface of the cylindrical portion 11.

The sleeve 4 is cylindrical and has an inner diameter slightly larger than the outer diameter of the tube 2, and has a larger diameter at one end than the protrusion 7 of the tube 2. A flange 16 is formed in contact with the side surface.

The nut 5 has an inner diameter at one end slightly larger than an outer diameter of the sleeve 4, and an inner axial side surface thereof abuts a flange 16 of the sleeve 4.
On the inner peripheral surface at the other end, a female screw 17 that is screwed with the male screw 15 of the nipple 3 is formed.

[0007] Since the conventional pipe joint 1 is configured as described above, the flange 16 of the sleeve 4 is directed toward the protruding portion 7 and the female screw 17 of the nut 5 is connected to the protruding portion 7 of the pipe 2.
Insert as side. When the female screw 17 of the nut 5 is screwed into the external thread 15 of the nipple 3 and the nut 5 is tightened to the nipple 3, the truncated cone shape of the seat 6 of the pipe 2 and the conical hole shape of the seat surface 12 of the nipple 3 are formed. The pipe joint 1 is assembled in close contact with the fluid, and the fluid is sent through the pipe 2 to the required equipment through the nipple 3.

[0008]

By the way, it is very difficult to form the front end 8 of the seat 6 of the pipe 2 into a perfect circle in the above-mentioned conventional pipe joint 1. When the pipe joint 1 is assembled, as shown in FIG. 4, the tip 8, for which it is difficult to ensure accuracy, comes into contact with the seating surface 12 of the nipple 3 and tightens the nut 5 with respect to the nipple 3. As a result, a part of the distal end portion 8 is not a perfect circle, so that it comes into close contact with the seat surface 12 in such a manner as to bite it. Therefore, at first, there is no leakage of fluid between the seat portion 6 and the seat surface 12, but it is difficult to secure the close contact between the seat portion 6 and the seat surface 12 when the fitting 1 is repeatedly attached and detached. Thus, there is a problem that a fluid (especially, a high-pressure gas) leaks from the pipe joint 1 due to the occurrence of a portion that is not completely in close contact.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is an object of the present invention to provide a highly reliable pipe joint which does not leak even if it is attached to and detached from any fluid many times. It was made for the purpose.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, a pipe joint according to the present invention has a tubular member having a truncated cone-shaped enlarged seat at an axial end, and a tubular seat corresponding to the enlarged seat. A nipple having a conical hole-shaped seating surface formed on the inner surface thereof, wherein the length of the generatrix of the truncated cone of the enlarged seat portion of the tubular material is longer than the length of the generatrix of the conical hole of the seating surface of the nipple. And forming the tip of the enlarged seat portion of the tubular material so as to protrude in a truncated conical shape from the seat surface of the nipple toward the inner rear side when the tubular material and the nipple are in close contact with each other. An annular concave portion is provided on the radially inner side of the enlarged seat portion to form a truncated conical protrusion having a thickness substantially equal to the main portion of the tube material, and the radially inner surface of the truncated conical portion is restrained from the inside. Elastic deformation inward in the radial direction Possible, characterized by being configured to obtain familiar to the conical hole shape seat of the nipple.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a pipe joint according to the present invention will be described below with reference to FIGS. 1 and 2, omitting details of the same parts as those of the prior art.

[0012]

The tubular member 21 is provided on its outer peripheral surface at one end with a projection 26 formed with a truncated cone-shaped enlarged seat portion 25 suitable for press molding or the like. Unlike the conventional example shown in FIG. 3, the projection 26 has a thickness substantially equal to that of the main body of the tubular member 21. Therefore, the annular recess 19 is formed inside the projection 26 in the radial direction. For this reason, the projection 26 can be somewhat flexed as a whole. The seat portion 25 is formed so as to decrease in diameter toward the axial end portion 27, the large diameter portion 28 is larger in diameter than the outer diameter of the tube 21, and the small diameter portion 29 is formed in the tube 21. It is almost equal to the inside diameter.

The nipple 22 has a conical hole-shaped seating surface 3 corresponding to the seating portion 25 of the pipe member 21 on the inner peripheral surface at one end of the cylindrical portion 30.
1 is formed so as to increase in diameter toward the distal end of the cylindrical portion 30. The large diameter portion 32 of the seating surface 31 is
The small diameter portion 33 is formed to be larger in diameter than the small diameter portion 29 of the tube 21. Therefore, the length of the generatrix of the truncated cone of the seat portion 25 is longer than the length of the generatrix of the conical hole of the seat surface 31. The external thread 34 is formed on the outer peripheral surface of the cylindrical portion 30. Note that the sleeve 23 and the nut 24 have the same structure as in the related art, and a description thereof will be omitted.

Since the pipe joint 20 is constructed as described above, the sleeve 23 is inserted into the pipe member 21 and the nut 24 is inserted into the sleeve 23, and the female screw 17 of the nut 24 is screwed into the external thread 34 of the nipple 22. Nut 24
Is tightened to the nipple 22, as shown in FIG. 2, the truncated cone of the seat portion 25 of the pipe member 21 and the seat surface 31 of the nipple 22 are formed.
The pipe joint 20 is assembled in close contact with the conical hole shape. In this case, the distal end portion 27 of the seat portion 25, for which it is difficult to achieve roundness processing accuracy, is released so as to protrude from the seating surface 31 of the nipple 2 toward the inner back side (left side in FIG. 1). Therefore, the distal end portion 27 does not contact the seat surface 31, the truncated cone of the seat portion 25 having high roundness and the elastic deformation of the seat surface 31 are possible, and the seat portion 25 is easily adapted to the seat surface 31, No prying occurs.

[0016]

As described above, the pipe joint according to the present invention comprises a pipe member having a truncated cone-shaped enlarged seat at the axial end and a conical hole-shaped seating surface corresponding to the enlarged seat portion of the pipe material. In a pipe joint with a nipple formed on the inner surface, the length of the generatrix of the truncated cone of the enlarged seat portion of the pipe material is formed longer than the length of the generatrix of the conical hole of the seat surface of the nipple. Since the tip of the enlarged seat portion of the pipe material is formed so as to protrude in the shape of a truncated cone toward the inside deeper than the seat surface of the nipple, the tip of the enlarged seat portion of the pipe material when the pipe joint is tightened. Does not bite into the seating surface of the nipple, and no matter how many times the pipe material and the nipple are attached and detached, the high-pressure fluid does not easily leak due to the biting.

Further, an annular concave portion is provided on the radially inner side of the enlarged seat portion to form a truncated conical projection having a thickness substantially equal to the main portion of the pipe material. Because it is not restrained, the frusto-conical projection can be elastically deformed inward in the radial direction, deformed to fit the conical hole-shaped seating surface of the nipple, and the enlarged seat and nipple Is always maintained in close contact with the bearing surface, and high-pressure fluid does not leak from the fitting. Then, it is only necessary to form an enlarged seat portion having an annular concave portion on the inner side in the radial direction at the tip of the pipe material, so that the pipe joint can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a partial axial sectional view showing an embodiment of a pipe joint according to the present invention.

FIG. 2 is an enlarged view of a seat portion and a seat surface portion of FIG. 1;

FIG. 3 is a partial axial sectional view of a conventional pipe joint.

FIG. 4 is an enlarged view of a seat portion and a seat surface portion of FIG. 3;

DESCRIPTION OF SYMBOLS 19 Annular recess 20 Pipe fitting 21 Pipe material 22 Nipple 23 Sleeve 24 Nut 25 Truncated cone-shaped enlarged seat 27 Tip end 31 Conical hole seat

Claims (1)

[Claims] 1. A pipe joint comprising: a pipe member having a frusto-conical seat formed at an axial end thereof; and a nipple having a conical hole-shaped seating surface corresponding to the seat of the tube formed on an inner surface thereof. The length of the generatrix of the truncated cone of the seat portion is formed longer than the length of the generatrix of the conical hole of the seat surface of the nipple, and at the time of close contact between the pipe material and the nipple, the tip of the seat portion of the pipe material is A pipe joint characterized in that it protrudes further inward than the seat surface of the nipple.