JP2001248767A - Pipe joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe joint with no leakage of high pressure fluid through a pressure contact face even when attachment and detachment is performed a multiplicity of times. SOLUTION: A tip 27 of an enlarged seat part 25 of a pipe material 21 protrudes toward a radially inner side and an axially deeper side than a conical hole shaped seat face 31 of a nipple 22. A conical vertical angle of a truncated cone outer face 35 of the enlarged seat part 25 is smaller than a conical vertical angle of the conical hole shaped seat face 31 in a free state, and an annular gap 36 expansively opening radially outward is formed between the truncated cone outer face 35 and the conical hole shaped seat face 31 in a state before adherence of the pipe material 21 and the nipple 22. A hollow truncated cone shaped flange 26 is elastically deformable toward a radially inward side, and in a closely adhered state of the enlarged seat part 25 and the conical hole shaped seat face 31, the hollow truncated cone shaped flange 26 deforms toward the radially inward side, the annular gap 36 disappears, and the truncated cone outer face 35 conforms with the conical hole shaped seat face 35 in a surface contact state.

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 an automobile or the like.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional fitting type pipe joint. The pipe joint 1 includes a pipe material 2, a nipple 3, a sleeve 4, and a nut 5.

[0003] The tube member 2 has an enlarged 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 seating surface 6 is reduced in diameter toward the distal end portion 8, the large diameter portion 9 is larger in diameter than the outer diameter of the tube 2, and the small diameter portion 10 is smaller than the inner diameter of the tube 2. Are also large diameter.

[0004] 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 surface 6 of the tube 2 expands in diameter toward the end of the cylindrical portion 11. ing. 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 one end has a larger diameter than the enlarged protrusion 7 of the tube 2. A flange 16 is formed in contact with the axial 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 constructed as described above, the flange 16 of the sleeve 4 is directed toward the enlarged projection 7 and the female screw 17 of the nut 5 is attached to the projection 7 of the pipe 2. Insert as side. And the male screw 1 of the nipple 3
When the female screw 17 of the nut 5 is screwed into the nut 5 and the nut 5 is tightened to the nipple 3, the frustoconical outer surface of the enlarged seat portion 6 of the pipe member 2 and the frustoconical seating surface 12 of the nipple 3 come into close contact with each other to form a pipe joint. 1 is assembled, and the fluid is sent from the inside of the tubing 2 to the required equipment via the inside of the nipple 3.

[0008]

By the way, in the above-mentioned conventional pipe joint 1, it is very difficult to machine the tip 8 of the seating surface 6 of the pipe 2 into a perfect circle. When the pipe joint 1 is assembled, the tip 8, for which it is difficult to ensure accuracy, comes into contact with the seating surface 12 of the nipple 3, and when the nut 5 is tightened with respect to the nipple 3, a part of the tip 8 is formed. Are not perfect circles, so they come into close contact with each other so as to bite into the seating surface 12. Therefore, at first, there is no leakage of fluid between the seat surface 6 and the seat surface 12, but it is difficult to secure the close contact between the seat surface 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. Aim.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, a pipe joint according to the present invention has a pipe member having a truncated cone-shaped enlarged seat portion at an axial end portion, and the expanded seat portion of the tube material is in close contact. And a nipple having a conical hole-shaped seating surface on the inner surface thereof pressed by the nipple, wherein the length of the generatrix of the truncated cone outer surface of the enlarged seat portion of the pipe material is the same as the generatrix of the conical hole-shaped seating surface of the nipple. It is formed longer than the length, so that when the enlarged seat portion of the tube material is in close contact with the conical hole seating surface of the nipple, the tip of the enlarged seat portion has a radius larger than the conical hole seating surface. An annular concave portion is provided on the radially inner side of the truncated cone-shaped enlarged seat portion, and has a thickness substantially equal to the main portion of the tube material and is elastic. A hollow frustoconical protruding edge is formed, and the enlarged seat portion is formed. The cone apex angle of the truncated cone outer surface is formed smaller than the cone apex angle of the conical hole-shaped seating surface in a free state of the hollow frusto-conical projection, whereby the pipe material and the nipple are in close contact with each other. An annular gap expanding radially outward is formed between the outer surface of the truncated cone and the seat surface of the conical hole. The inner surface is not constrained from the inside, and is entirely elastically deformable inward in the radial direction, and in a state in which the enlarged seat portion of the pipe material and the conical hole-shaped seat surface of the nipple are in close contact with each other. The hollow frusto-conical protruding edge is elastically deformed inward in the radial direction so that the annular gap disappears, and the frusto-conical outer surface is adapted to be adapted to be in surface contact with the conical hole-shaped seating surface. I do.

[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.

As shown in FIG. 1, an outer peripheral surface of one end of a tubular member 21 is formed into a truncated cone-shaped enlarged seat portion 2 by press molding or the like.
5 are formed. The enlarged seat portion 25 is formed so as to decrease in diameter toward its axial end portion 27, and has an annular concave portion 19 on its radial inside, unlike the conventional example shown in FIG. It has a hollow structure having a thickness substantially equal to the main portion of the tube material 21. As a result, a hollow frustoconical protruding edge 26 is formed on the distal end side of the enlarged seat 25. The tube 21 is formed entirely of elastic metal, and the hollow frusto-conical ridge 26 can be flexed somewhat elastically as a whole. Large diameter portion 28 of enlarged seat 25
Has a larger diameter than the outer diameter of the tube material 21 and its small diameter portion 29
Is substantially equal to the inner diameter of the tube 21. The radially inner surface of the hollow frusto-conical projection 26 is not restricted from the inside in the radial direction, and is entirely elastically deformable inward in the radial direction.

The nipple 22 has a conical hole-shaped seating surface 31 corresponding to the enlarged seating portion 25 of the tubular member 21 formed on the inner peripheral surface at one end of the cylindrical portion 30. The conical hole-shaped seating surface 31 is formed so as to increase in diameter toward the distal end of the cylindrical portion 30. As shown in FIG. The diameter of the small-diameter portion 33 of the conical hole-shaped seating surface 31 is larger than the diameter of the small-diameter portion 29 of the tubular material 21. Therefore, the tubing 21
The length of the generatrix of the truncated cone outer surface 35 of the enlarged seat portion 25 of the nipple 22 is longer than the length of the generatrix of the conical hole-shaped seating surface 31 of the nipple 22. Frusto-conical outer surface 35 and conical hole-shaped bearing surface 3 of nipple 22
At the time of the contact of 1, the distal end portion 27 of the enlarged seat portion 25 protrudes radially inward and axially deeper than the conical hole-shaped seating surface 31 into a truncated cone shape. An external thread 34 is formed on the outer peripheral surface of the cylindrical portion 30.

In the free state shown in FIG. 3, which is a state before the enlarged seat portion 25 of the tubular member 21 is pressed against the conical hole-shaped seating surface 31 of the nipple 22, the cone apex angle of the truncated cone outer surface 35 of the enlarged seat portion 25 is , The nipple 22 is formed smaller than the conical apex angle of the conical hole-shaped seating surface 31. Therefore, before the pipe 21 and the nipple 22 are in close contact with each other, between the outer surface 35 of the truncated cone and the seating surface 31 of the conical hole, as shown in FIG. Is formed.

Since the pipe joint 20 is constructed as described above, as shown in FIG. 1, a sleeve 23 is fitted around the outer periphery of a pipe member 21 and a nut 24 is provided around the sleeve 23.
When the female screw 17 of the nut 24 is screwed into the external thread 34 of the nipple 22 and the nut 24 is tightened to the nipple 22, the truncated conical outer surface 35 (FIG. 3) of the enlarged seat portion 25 of the pipe material 21 It is pressed against the conical hole-shaped seating surface 31 in the axial direction. At this time, the small diameter portion 3 of the conical hole-shaped seating surface 31
3 is the truncated cone outer surface 35 of the enlarged seat 25 of the tube 21
, The hollow frustoconical ridge 26 is gradually elastically deformed radially inward. As a result, the truncated cone-shaped outer surface 35 gradually becomes parallel to the conical hole-shaped seating surface 31, and the both surfaces 31, 35 are finally brought into close contact. In this tightened state, the gap 36 disappears, and the hollow frusto-conical protruding edge 26 fits into the conical hole-shaped seating surface 31 in a surface contact state. In this state, the hollow frusto-conical protruding edge 26 always exerts a reaction force accompanying elastic deformation on the conical hole-shaped seating surface 31. As a result, the frusto-conical outer surface 35 of the enlarged seat 25 has a conical hole-shaped surface. It is pressed against the seating surface 31 and conforms, and the adhesion between the two surfaces 31 and 35 becomes strong, and an excellent seal is obtained.

At the time of this close contact operation, the tip 27 of the enlarged seat 25, which is difficult to achieve the roundness machining accuracy, is located on the inner rear side (left side in FIG. 1) of the conical hole-shaped seating surface 31 of the nipple 2. ) So as to protrude toward the conical hole-shaped seating surface 31, the front end portion 27 does not abut against the conical hole-shaped seating surface 31.
It does not pry on 1.

Since the pipe joint 20 is constructed as described above, the sleeve 23 is fitted to the pipe member 21 and the nut 24 is fitted to the sleeve 23, and the external thread 34 of the nipple 22 is fitted.
When the female screw 17 of the nut 24 is screwed into the nut and the nut 24 is fastened to the nipple 22, the state shown in FIG.
As shown in FIG.
5 and the conical hole-shaped seating surface 31 of the nipple 22 are in close contact with each other, and the pipe joint 20 is assembled. In this case, the distal end portion 27 of the enlarged seat portion 25, for which it is difficult to achieve the roundness processing accuracy, escapes so as to protrude from the seat surface 31 of the nipple 2 toward the inner back side (left side in FIG. 1). As a result, the distal end portion 27 does not come into contact with the conical hole-shaped seating surface 31 and no prying occurs.

[0018]

As described above, in the pipe joint according to the present invention, a pipe member having an enlarged seat having an outer surface of a truncated cone at the axial end, and a conical hole seat in which the enlarged seat of the pipe is pressed. In a pipe joint having a nipple having a surface formed thereon, the length of the generatrix of the outer surface of the truncated cone of the enlarged seat portion of the pipe material is formed to be longer than the length of the generatrix of the conical hole-shaped seating surface of the nipple, so that the pipe material and the nipple are in close contact. Sometimes, the distal end of the enlarged seat portion of the pipe material projects radially inward from the conical hole-shaped seating surface of the nipple and toward the far side to form a hollow frustoconical protruding edge. When the pipe is tightened, the tip of the enlarged seat of the tube does not bite into the conical hole-shaped seating surface of the nipple, and even if the tube and the nipple are attached and detached many times, high-pressure fluid leaks due to the bite It doesn't get easier.

An annular recess is provided on the radially inner side of the enlarged seat to form a frustoconical protruding edge having a thickness substantially equal to that of the main portion of the tubular material. Can be elastically deformed inward in the radial direction so as not to be restrained from the inside, and the cone apex angle of the hollow frusto-conical protruding edge is in its free state, and the cone apex of the conical hole-shaped seating surface of the nipple. Because it was smaller than the corner,
Before the enlarged seat and the conical hole seating surface are tightly joined, an annular gap expanding radially outward is formed between both surfaces, and as the enlarged seat is pressed against the conical hole seating surface, a hollow cone is formed. The trapezoidal protruding edge elastically deforms inward in the radial direction, the annular gap gradually disappears, and the outer surface of the hollow frustoconical protruding edge always exerts a pressing force on the conical hole seating surface based on the reaction force generated by the elastic deformation. And the hollow frusto-conical ridge will therefore conform to the conical seat and the close contact between the enlarged seat and the conical seat of the nipple will always be maintained, preventing high pressure fluid from leaking out of the fittings . In terms of structure, it is only necessary to form a truncated cone-shaped enlarged seat having an annular concave portion on the inner side in the radial direction at the distal end of the pipe material. Therefore, according to the present invention, a 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 a partially enlarged sectional view of the pipe joint of FIG. 1 in a tightened state.

FIG. 3 is an enlarged cross-sectional view showing a relationship between the nipple of the enlarged truncated conical seat and the conical hole-shaped seating surface of the nipple when the truncated conical enlarged seat at the tip of the tubular member is in a free state.

FIG. 4 is a partial axial sectional view of a conventional pipe joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 19 Annular recess 20 Pipe fitting 21 Pipe material 22 Nipple 23 Sleeve 24 Nut 25 Truncated cone-shaped enlarged seat part 26 Truncated cone-shaped protruding edge 27 Tip part 31 Conical hole-shaped seating surface 35 Truncated cone outer surface 36 Annular clearance

Claims (1)

[Claims] A frusto-conical enlarged seat (2) is provided at an axial end portion.
5), and an enlarged seat (2) of the tube material.
5) a nipple (22) having an inner surface with a conical hole-shaped seating surface (31) pressed in close contact with the nipple (22); 3
5) the length of the generatrix is longer than the length of the generatrix of the conical hole-shaped seating surface (31) of the nipple (22);
Thereby, when the enlarged seat (25) of the pipe (21) is in close contact with the conical hole-shaped seating surface (31) of the nipple (22), the tip (27) of the enlarged seat (25) An annular concave portion (19) is formed so as to protrude radially inward and axially deeper than the conical hole-shaped seating surface (31), and radially inward of the truncated conical seat (25). A resilient hollow frustoconical ridge (26) having a wall thickness substantially equal to that of the main body of the tubular member (21) and having an elasticity is formed, and a cone of a frustoconical outer surface (35) of the enlarged seat (25) is formed. The apex angle is smaller than the conical apex angle of the conical hole-shaped seating surface (31) in a free state of the hollow frusto-conical projection (26), whereby the pipe material (21) and the nipple ( 22), the outer surface of the truncated cone (3)
An annular gap (36) expanding radially outward is formed between the conical hole-shaped seating surface (5) and the conical hole-shaped seating surface (31), and the hollow frusto-conical protruding edge (26) is formed. The inner surface in the radial direction is not constrained from the inside, and is entirely elastically deformable inward in the radial direction. The enlarged seat (25) of the pipe (21) and the nipple (2)
In the state where the conical hole-shaped seating surface (31) of 2) is in close contact, the hollow frusto-conical protruding edge (26) is elastically deformed inward in the radial direction and the annular gap (36) disappears. A pipe joint characterized in that the truncated cone outer surface (35) is adapted to fit in a conical hole-shaped seating surface (31) in surface contact.