Inner ring

Abstract

A pipe-connecting device including a resin-made tube and an inner ring. The inner ring has a flared portion and a tip-contracted outer-circumferential flared surface. The tip-contracted outer-circumferential flared surface is press-inserted into an end portion of the tube to cause the end portion of the tube to be flared and deformed. A section shape of the outer-circumferential flared surface in a direction extending along an axis of the inner ring body is formed into a convex curved surface passing through a first place, which is a maximum-diameter portion of the flared portion, a second place, which is the tip end side of the flared portion of the inner ring body, and a third place, which is between the first place and the second place, and in which a diameter is equal to an outer diameter of the tube with respect to the axis.

Claims

1. A pipe-connecting device comprising: a resin-made tube; and, an inner ring in which a flared portion is formed in an outer circumferential portion of an inner ring body that is to be press-inserted into the resin-made tube, said inner ring body having a tip-contracted outer-circumferential flared surface formed in a tip end side of the flared portion, said tip-contracted outer-circumferential flared surface being press-inserted into an end portion of the resin-made tube to cause the end portion of the resin-made tube to be flared and deformed, wherein: a section shape of the outer-circumferential flared surface in a direction extending along an axis of the inner ring body is formed into a convex curved surface passing through a first place, which is a maximum-diameter portion of the flared portion, a second place, which is the tip-end side of the flared portion of the inner ring body, and a third place, which is between the first place and the second place, and in which a diameter is equal to an outer diameter of the tube with respect to the axis, the convex curved surface being defined as an arc having a center at a location farther than the axis with respect to the outer-circumferential flared surface in a radial direction, and, an angle formed by a line extending tangential to the outer-circumferential flared surface in the third place and the axis is 30 to 60 degrees (3060).

2. The pipe-connecting device according to claim 1, wherein seal element portions, which are press-contacted with seal configuring portions disposed in the pipe connecting device to constitute inner seal portions, are formed in a basal-end side of the inner ring body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a side view of an inner ring (Embodiment 1).

(2) FIG. 2 is a sectional view of the inner ring of FIG. 1.

(3) FIG. 3 is an enlarged sectional view of main portions and showing the shape of a tip-end side of the inner ring of FIG. 1.

(4) FIG. 4 is a sectional view of a state where a tube is connected to a pipe connecting device by using the inner ring of FIG. 1.

(5) FIG. 5 is an enlarged sectional view showing main portions of FIG. 4.

(6) FIG. 6 is a sectional view showing a press-contacted situation in the case where the inner ring of FIG. 1 is inclinedly press-inserted into an end portion of the tube.

(7) FIG. 7 shows the shape of the tip-end side of the inner ring, (a) shows a case where the tangential angle in a third place is 30 degrees, and (b) shows a case where the tangential angle in the third place is 60 degrees.

(8) FIG. 8 shows an inadequate fitted state of the inner ring and the tube, (a) shows a case where the tangential angle in the third place is smaller than 30 degrees, and (b) shows a case where the tangential angle in the third place is larger than 60 degrees.

(9) FIG. 9 is a sectional view of an inner ring (Embodiment 2).

(10) FIG. 10 is a sectional view of a state where a tube is connected to a pipe connecting device by using the inner ring of FIG. 9.

(11) FIG. 11 is a sectional view showing a conventional inner ring.

(12) FIG. 12 is a sectional view showing a situation of adequate press contact between the conventional inner ring and a tube.

(13) FIG. 13 is a sectional view showing a situation of inadequate press contact between the conventional inner ring and the tube.

MODE FOR CARRYING OUT THE INVENTION

(14) Hereinafter, embodiments of the inner ring of the invention will be described with reference to the drawings. In a pipe-connecting device A shown in FIGS. 4, 5, and 10 and the like, three axes, i.e., the axis Y of a pipe joint body 1, the axis P of an inner ring 3, and the axis X of a tube 4 are drawn so that they are identical ones arranged on the same straight line (the axis Y=the axis P=the axis X).

(15) In the specification, it is defined that tip end side and tip end in components of the pipe joint body 1, a union nut 2, the inner ring 3, and the tube 4 indicate the side (or the direction) in which the tube 4 separates from the pipe joint body 1 in the direction of the axis Y in FIGS. 4, 5, and the like, and basal end side and basal end indicate the side (or the direction) in which the tube 4 approaches the pipe joint body 1 in the direction of the axis Y.

Embodiment 1

(16) FIGS. 1 to 3 show the inner ring 3, and FIGS. 4 and 5 show the pipe-connecting device A to which the tube 4 is connected by using the inner ring 3.

(17) The pipe-connecting device A is configured by a pipe joint through which tubes are connected to each other, has the pipe joint body 1, the union nut 2, and the inner ring 3, and is used for communicatingly connecting the tube 4 in a state where the inner ring body 3A is press-inserted into a tube end portion 4C which is an end portion of a tube.

(18) All of the pipe joint body 1, the union nut 2, the inner ring 3, and the tube 4 are made of a resin such as a fluorine resin (for example: PTFE, PFA, ETFE, CTFE, or ECTEF) having excellent heat resistance and chemical resistance.

(19) When the pipe joint body 1, the inner ring 3, and the tube 4 are made of the above-mentioned fluorine resin, the union nut 2 may be formed by a resin such as polyamide, polypropylene, or polyethylene. All of the pipe joint body 1, the union nut 2, the inner ring 3, and the tube 4 may be formed by a resin such as polyamide, polypropylene, or polyethylene.

(20) The pipe joint body 1 has a tubular structure having: a tubular trunk portion 1C; a tubular screwing portion 1A which is disposed in its tip end side in the direction of the axis Y; a tubular receiving port 1B which is disposed in its basal end side in the direction of the axis Y; one small-diameter tubular portion 1a which is formed on the radially inward side of a root portion of the tubular screwing portion 1A; another small-diameter tubular portion 1b which is formed on the radially inward side of the receiving port 1B; and an internal flow path 6 which is configured by an inner circumferential surface (not designated by a reference numeral). For example, the pipe joint body is formed into a component having a shape which is symmetrical about the direction of the axis Y.

(21) In the tubular screwing portion 1A, an external thread 7 is formed from the outer circumference of its tip end portion toward the basal end side, a tip-expanded inner circumferential surface 8 is formed on the inner circumference of its tip end portion, and a linear inner circumferential surface 9 having the same inner diameter is formed on the basal end side of the inner circumferential surface 8.

(22) A linear outer circumferential surface 10 having a constant diameter is formed on the radially outward side of the small-diameter tubular portion 1a, and an inclined inner circumferential surface 5 having a tip-expanded shape in which the diameter is gradually increased as further advancing toward the tip end side in the direction of the axis Y is formed in a tip end portion on the radially inward side.

(23) A tubular annular groove m is formed between the outer circumferential surface 10 of the one small-diameter tubular portion 1a and the inner circumferential surface 9 of the tubular screwing portion 1A.

(24) In the pipe joint body 1, as shown in FIG. 4, the receiving port 1B has the same structure as the tubular screwing portion 1A, and the other small-diameter tubular portion 1b has the same structure as the one small-diameter tubular portion 1a. As the structure shown in FIG. 10, alternatively, the receiving port 1B and the other small-diameter tubular portion 1b may have another structure.

(25) The union nut 2 is configured by a resin-made nut, and, in an inner circumferential portion, has an internal thread 13 which is screwed with the external thread 7 of the tubular screwing portion 1A, and an annular flange portion 12 which is located on the tip end side with respect to the internal thread 13, and which projects toward the radially inner side.

(26) The inner diameter portion of the flange portion 12 is set as an inner circumferential surface 12a in which the diameter is substantially equal to or very slightly larger than the outer diameter of the tube 4 so that the tube 4 can pass therethrough. The basal end side of the flange portion 12 is configured as a pressing portion 12b that presses the tip-end side outer circumferential surface (outer circumferential surface of a tip-contracted press-contact portion 4a) of the tube end portion 4C into which the inner ring body 3A is press-inserted, in the direction of the axis Y of the pipe joint body 1.

(27) Therefore, the pressing portion 12b is configured so that the portion is caused to press the tip-end side outer circumferential surface of the tube end portion 4C in the direction of the axis Y of the pipe joint body 1, by the screw advancement caused by screwing the internal thread 13 with the external thread 7 of the tubular screwing portion 1A.

(28) Although the inner circumferential surface 12a of the flange portion 12 is drawn to have a constant diameter, the surface may be formed into a tapered inner circumferential surface in which the inner diameter is gradually increased as further separating from the internal thread 13 (as further approaching toward the tip end side in the direction of the axis Y).

(29) As shown in FIGS. 1 to 5, the inner ring 3 has a tubular structure having the inner ring body 3A which is press-inserted into the tube end portion 4C from an opening of the tube 4, and a fitting tubular portion 3B which is on the basal end side of the inner ring body 3A, and which projects toward the basal end of the inner ring body 3A from the opening of the tube 4.

(30) The inner circumferences of the inner ring body 3A and the fitting tubular portion 3B are formed into an inner circumferential portion 3w which has the same diameter, and which is uniform, and as a fluid passage.

(31) In the inner ring body 3A, a flared portion 3f is formed in an outer circumferential portion 3G, and a tip-contracted outer-circumferential flared surface 3a is formed in the tip end side of the flared portion 3f. In the basal end side of the flared portion 3f, a maximum-diameter portion 3b, and a tip-expanded outer circumferential portion 3c which is in the basal end side of the maximum-diameter portion 3b, and in which the outer diameter is further decreased as further advancing toward the fitting tubular portion 3B are formed. A trunk outer circumferential portion (trunk outer circumferential surface) 3d having a constant outer diameter is formed in the basal end side of the tip-expanded outer circumferential portion 3c.

(32) In the drawings of the application, the maximum-diameter portion 3b of the inner ring is drawn to have a structure having a constant axial length. Even in a structure corresponding to a boundary in which the outer-circumferential flared surface 3a is immediately changed to the tip-expanded outer circumferential portion 3c, there is no technical difficulty. In this case, the boundary 3g shown in FIG. 6 and the like coincides with the maximum-diameter portion 3b.

(33) The tip-contracted outer-circumferential flared surface 3a of the flared portion 3f is formed into a convex curved surface in which the whole is radially outwardly convex, the maximum-diameter portion 3b is formed in the basal end side of the outer-circumferential flared surface 3a, and the outer-circumferential flared surface 3a and the maximum-diameter portion 3b are press-inserted into the tube end portion 4C, whereby the tube end portion 4C is deformed in a flared manner.

(34) In a tip end portion of the inner ring body 3A, a cut-shaped deformation preventing portion 16 configured by an inner circumferential surface which is inclined so that the diameter becomes larger as further advancing toward the tip end of the axis P is formed. The deformation preventing portion 16 prevents a tip end portion side of the outer-circumferential flared surface 3a from, after the outer-circumferential flared surface 3a is press-inserted into the tube end portion 4C, deforming and projecting in the radial inward direction (toward the fluid passage). The deformation preventing portion 16 further prevents the tip end side of the outer-circumferential flared surface 3a from being further deformed and projected in the radial inward direction (toward the fluid passage) by the force and speed of the flow of the fluid, whereby the press contact force of the tip end portion of the outer-circumferential flared surface 3a is prevented from being reduced.

(35) In the fitting tubular portion 3B, a projecting cylindrical portion 14 which is press-inserted into the annular groove m of the pipe joint body 1, and an annular small projection 15 which is located in the radial inward side of the projecting cylindrical portion 14, and which includes an inclined outer circumferential surface 11 are formed. In a basal end portion of the annular small projection 15, a cut-shaped deformation preventing portion 17 configured by an inner circumferential surface which is inclined so that the diameter becomes larger as further advancing toward the basal end of the axis P of the inner ring body 3A is formed. The deformation preventing portion 17 prevents the basal end side of the annular small projection 15 from deforming and projecting in the radial inward direction (toward the fluid passage).

(36) The portion between the inclined outer circumferential surface 11 of the annular small projection 15 and the inner circumferential surface 14a of the projecting cylindrical portion 14 is formed into an annular recess. The small-diameter tubular portion 1a of the pipe joint body 1 is fitted into the recess. This fitting enables the inclined outer circumferential surface 11 of the annular small projection 15 and the inclined inner circumferential surface 5 of the small-diameter tubular portion 1a to be butted against each other.

(37) The diameter difference (step difference) between the outer circumferential surface 3e of the fitting tubular portion 3B and the trunk outer circumferential portion 3d is set to be substantially equal to the thickness of the tube 4 so that a gap is not formed as far as possible between the outer circumferential surface 4B of the tube 4 and the inner circumferential surface 9 of the tubular screwing portion 1A.

(38) In the tube 4, when the inner ring body 3A is press-inserted into the tube end portion 4C to flare and deform the tube end portion, the tip-contracted press-contact portion 4a which is press-contacted with the outer-circumferential flared surface 3a of the inner ring body 3A, a maximum flared press-contact portion 4b which is press-contacted with the maximum-diameter portion 3b of the inner ring body 3A, a tip-expanded press-contact portion 4c which is butted against the outer circumferential portion 3c of the inner ring body 3A, and a trunk press-contact portion 4d which is press-contacted with the trunk outer circumferential portion 3d of the inner ring body 3A are formed.

(39) In the formation state, the diameter of an internal flow passage 4W configured by the inner circumferential surface of the tube 4, that of the inner circumferential portion 3w constituting the fluid passage of the inner ring 3, and that of the internal passage 6 of the pipe joint body 1 are set to have the same dimension d (see FIGS. 3 and 4), i.e., to be flush. However, the formation state is not limited to the case where the surface flush state is set.

(40) After the inner ring body 3A is press-inserted into the tube end portion 4C of the tube 4, the tube is inserted and disposed into the pipe joint body 1. As shown in FIGS. 4 and 5, then, the internal thread 13 of the union nut 2 is screwed with the external thread 7 of the tubular screwing portion 1A of the pipe joint body 1, and screw advanced, thereby causing the pressing portion 12b of the union nut 2 to press the tip-end side outer circumferential surface (outer circumferential surface of the tip-contracted press-contact portion 4a) of the tube end portion 4C in the direction of the axis Y.

(41) This pressing causes the projecting cylindrical portion 14 of the inner ring 3 to be press-inserted into the annular groove m of the pipe joint body 1, and the inclined outer circumferential surface 11 of the inner ring 3 to be butted against and press-contacted with the inclined inner circumferential surface 5 of the pipe joint body 1.

(42) When the tube 4 into which the inner ring 3 is press-inserted as described above is inserted into and connected with the pipe-connecting device A, at least three seal portions (S1, S3, S4) are configured as described below.

(43) The first seal portion S1 is a seal portion configured by: press contact between the tip-contracted press-contact portion 4a of the tube 4 and the outer-circumferential flared surface 3a of the inner ring body 3A; that between the maximum flared press-contact portion 4b of the tube 4 and the maximum-diameter portion 3b of the inner ring body 3A; that between the tip-expanded press-contact portion 4c of the tube 4 and the outer circumferential portion 3c of the inner ring body 3A; and the trunk press-contact portion 4d of the tube 4 and the trunk outer circumferential portion 3d of the inner ring body 3A.

(44) A second seal portion S2 is a seal portion configured in the case where a structure in which the tip-expanded press-contact portion 4c of the tube 4 and the tip-expanded inner circumferential surface 8 in the tubular screwing portion 1A of the pipe joint body 1 are press-contacted with each other is employed.

(45) The third seal portion S3 is a seal portion configured by: press contact between the outer circumferential surface of the fitting tubular portion 3B of the inner ring 3 and a basal end side portion of the inner circumferential surface 9 of the tubular screwing portion 1A of the pipe joint body 1; and further press contact between the fitting tubular portion 3B, more specifically the inner circumferential surface 14a of the projecting cylindrical portion 14, and the outer circumferential surface 10 of the small-diameter tubular portion 1a of the pipe joint body 1.

(46) The fourth seal portion S4 is a seal portion configured by press contact due to collision butting between the inclined outer circumferential surface 11 of the annular small projection 15 of the inner ring 3 and the inclined inner circumferential surface 5 of the small-diameter tubular portion 1a of the pipe joint body 1.

(47) The configuration of the first, third, and fourth seal portions S1, S3, S4 prevents the fluid flowing through the tube 4, the inner ring 3, and the pipe joint body 1 from entering between contact surfaces of the tubular screwing portion 1A of the pipe joint body 1 and the tube end portion 4C to leak therefrom, and attains a perfect seal.

(48) When, among the first, third, and fourth seal portions S1, S3, S4, the first seal portion S1 is surely sealed, the fluid does not enter nor leak from between the tubular screwing portion 1A of the pipe joint body 1 and the tube end portion 4C, and a satisfactory seal is ensured. In order to ensure a more perfect seal, however, it is preferable to dispose at least one of the third seal portion S3 and the fourth seal portion S4.

(49) In the first seal portion S1, the press contact between the tip-contracted press-contact portion 4a of the tube 4 and the outer-circumferential flared surface 3a of the inner ring body 3A is configured in the following manner.

(50) As shown in FIG. 3, namely, a sectional shape of the outer-circumferential flared surface 3a along the direction of the axis P of the inner ring body 3A is formed so as to constitute a convex curved surface passing through: a first place e1 which is the maximum-diameter portion 3b of the flared portion 3f; a second place e2 which is the tip end on the side of the tube press insertion; and a third place e3 which is between the first place e1 and the second place e2, and in which the diameter is equal to the outer diameter D of the tube 4 with respect to the axis P.

(51) In FIG. 3, for example, the first place e1 is a place where, in the maximum-diameter portion 3b of the flared portion 3f, is the tip end on the side of the tube press insertion, and the angle formed by the tangential line L of the outer-circumferential flared surface 3a in the third place e3 and the axis P is 30 to 60 degrees (3060).

(52) More specifically, in FIG. 3, the sectional shape of the outer-circumferential flared surface 3a along the axis P is defined as an arc (a three point arc or a three point curve) which passes through the above-described three points or the first to third places e1 to e3, which has a center i, and which has a radius R. In the shape drawn in FIG. 3, the boundary between the outer-circumferential flared surface 3a and the deformation preventing portion 16 is the first place e1, that between the outer-circumferential flared surface 3a and the maximum-diameter portion 3b is the second place e2, and the tangential angle 42 degrees.

(53) The outer diameter D of the tube 4 is the diameter of the outer circumferential surface 4B. In FIG. 3, the center i of the arc of the radius R is in the vicinity of the axis P, but the position is variously changed in accordance with conditions of the tangential angle and the like.

(54) In the configuration, in this way, the tip-contracted outer-circumferential flared surface 3a is formed into a convex curved surface which is defined as described above, the following effects are attained.

(55) It is assumed that, since the inner ring body 3A is press-inserted into the tube end portion 4C and inclinedly press-inserted, a relative angle exists between the axis P of the inner ring body 3A and the axis X of the tube as shown in FIG. 6.

(56) Even in an unanticipated situation in which the inner ring body is inclinedly press-inserted, a first press-contact portion a1 is formed between the outer-circumferential flared surface 3a of the inner ring body 3A and the tip-contracted press-contact portion 4a of the tube 4, and the first press-contact portion a1 can attain press contact which has a ring-like shape that is not intermittent in the circumferential direction, and which has an area that is wide in the direction of the axis P.

(57) Namely, the press contact of the area having a large width does not depend on the material, thickness, and flare amount of the tube 4, and exactly can be press contact which is continuously integrated from the first press-contact portion a1 of the conventional art shown in FIG. 6 to the second press-contact portion a2.

(58) When the relative angle exists between the axis P of the inner ring body 3A and the axis X of the tube, the bending (flared bending) of a portion which changes in a flared manner from the free diameter portion (the portions which are designated by the reference numerals 4A and 4B in FIG. 6) of the tube 4 to the tip-contracted press-contact portion 4a is gentle in a bending-direction outward portion s of the tube 4 as shown in FIG. 6. Therefore, a state where the tip-contracted press-contact portion 4a is pressed against the outer-circumferential flared surface 3a of the inner ring body 3A is formed, and a strong press-contact state is attained.

(59) In a bending-direction inward portion v of the tube 4, the bending (flared bending) of a portion which changes in a flared manner from the free diameter portion of the tube 4 to the tip-contracted press-contact portion 4a changes steeply (abruptly) to exert a function of separating the outer-circumferential flared surface 3a of the inner ring body 3A and the tip-contracted press-contact portion 4a from each other, and a weak press-contact state is obtained.

(60) In the configuration of the application, however, the annular first press-contact portion a1 having an area that is wide as described above is realized (maintained) also in the bending-direction inward portion v where the press contact is weak, and sufficient press contact can be performed. Therefore, it is possible to eliminate the conventional defect that the surface-pressure reduced portion n or the non-contact portion n is produced.

(61) For reference, FIG. 7(a) shows the tip end portion of the inner ring in a case where the tangential angle is 30 degrees, and FIG. 7(b) shows the tip end portion of the inner ring in a case where the tangential angle is 60 degrees. The figures are exemplified views of a section of main portions. In FIGS. 7(a) and (b), the inner ring 3 has different shapes and dimensions in the portion from the outer-circumferential flared surface 3a to the tip end side, but has the same shape and dimensions in the portion from the maximum-diameter portion 3b to the basal end side.

(62) In any case, the tube 4 is smoothly flared so as to attain a state where the tube 4 extends along the outer-circumferential flared surface 3a, and press-inserted into the inner ring 3.

(63) In the case where, as described above, the satisfactory first press-contact portion a1 which has an area that is wide in the direction from the tip end portion of the inner ring 3 toward the basal end side of the axis P, and which has a nonintermittent annular shape is formed between the outer-circumferential flared surface 3a of the inner ring body 3A and the tip-contracted press-contact portion 4a of the tube 4, even when the fluid is a highly penetrative liquid, it is possible to prevent the defect that, as in the conventional art shown in FIG. 13, the inner ring body 3A is inclinedly press-inserted, the fluid is caused by the capillary action or the like to penetrate from the non-contact portion n into the gap portion k between the outer-circumferential flared surface 3a of the inner ring body 3A and the tip-contracted press-contact portion 4a of the tube 4.

(64) The conventional defect that the old fluid which is previously flown and collected in the gap portion k oozes out from the non-contact portion n, and is mixed with the replaced new fluid, and, because of the mixture, the purity of the new fluid is lowered, and the replaced new fluid is modified can be eliminated by the first press-contact portion a1. Furthermore, it is possible to eliminate the other defect that a lot of time, washing fluid, and replacement fluid are consumed in washing and replacement.

(65) As a structure that is different from the invention in which, as described above, the outer-circumferential flared surface 3a of the inner ring body 3A has a large diameter, and a convex curved surface, it is contemplated that means for further reducing the angle with respect to the axis P as compared to that with respect to the outer-circumferential flared surface 3a of the conventional inner ring body 3A shown in FIG. 11, i.e., means for further reducing the angle t of the outer-circumferential flared surface 3a of a tip-contracted conical surface may be employed.

(66) In order that a first press-contact portion which is not circumferentially intermitted is obtained by this means, however, the length in the direction of the axis P is inevitably considerably prolonged. In this case, the length of the inner ring body 3A is largely increased as compared to the present situation (FIG. 11). In the case where there is a relative angle between the axis P of the inner ring body 3A and the axis X of the tube, in addition, the press contact between the tube 4 and the inner ring 3 in a bending-direction inward portion (see bending-direction inward portion v shown in FIG. 6) becomes weak as described above, and there is a possibility that penetration may occur.

(67) In the case where the tangential angle in the third place e3 is larger than 60 degrees (>60), the radius (curvature) R of the outer-circumferential flared surface 3a in the direction along the axis P is reduced as shown in FIG. 8(b). In this case, the press insertion load for the tube 4 is large, a strong force is required in the insertion of the inner ring 3, and reduction of the mechanical properties of the tube material, i.e., modification of the tube material is caused by rapid flaring of the tube. In addition, for example, there arises a necessity to soften the tube 4 by heating. Therefore, the possibility that the tube is modified is increased.

(68) In the case where press insertion is performed in this way, as shown in FIG. 8(b), bending in the flared portion extending from the natural-diameter portion of the tube 4 to the press-contact portion 4a cannot follow the outer-circumferential flared surface 3a, the contact area itself (see a1 in FIG. 6) between the both portions is reduced, and a stable sealing function cannot be expected. In addition, a portion where the tube 4 cannot extend along the outer-circumferential flared surface 3a, i.e., a separating portion F is largely produced to form a liquid pool, and a possibility that the liquid replacement property is adversely affected is large.

(69) By contrast, in the case where the tangential angle in the third place e3 is smaller than 30 degrees (<300), the radius (curvature) R of the outer-circumferential flared surface 3a in the direction along the axis P is increased as shown in FIG. 8(a), and a gently curved surface is formed. In this case, the tube 4 cannot be deformed along the gently curved surface, and there arises an inconvenience that a gap G is formed between the tube inner circumferential surface 4A and the outer-circumferential flared surface 3a. This produces a contact state which is similar to the conventional inconvenient state, and is not preferable.

(70) When the tangential angle is smaller than 30 degrees or larger than 60 degrees, various inconveniences are easily produced as described above. Therefore, it is preferable that the tangential angle is 30 to 60 degrees.

(71) Although, in Embodiment 1, the outer-circumferential flared surface 3a of the inner ring body 3A is formed into a spherical convex curved surface, the shape of the outer-circumferential flared surface 3a is not limited to a spherical shape, and may be a smooth convex curved surface such as a catenary curved surface.

(72) As described above, the outer-circumferential flared surface 3a and the tip-contracted press-contact portion 4a can be set to a press-contact state without increasing the dimension of the outer-circumferential flared surface 3a in the direction of the axis P, and a strip-like press-contact portion which is wide in the axial direction can be formed. Therefore, it is possible to prevent the conventional defect (penetration possibility) from occurring.

Embodiment 2

(73) As shown in FIGS. 9 and 10, an inner ring 3 of Embodiment 2 is different from the inner ring of Embodiment 1 only in the configuration of the fitting tubular portion 3B. Because of this difference, also in the pipe-connecting device A, the configuration of the fitting tubular portion 3B of the pipe joint body 1 is different. In FIG. 10, the receiving port 1B and the other small-diameter tubular portion 1b are drawn in the same manner as those of the pipe joint body 1 shown in FIG. 4.

(74) In the fitting tubular portion 3B of the inner ring 3, namely, the outer circumferential surface 3e, the inner circumferential portion 3w, and a tip-contracted inner circumferential surface 20 which is tip-contracted as advancing toward the tip end of the inner ring 3 in the basal end side are formed. In the pipe joint body 1, by contrast, the tip-contracted small-diameter tubular portion 1a having an outer circumferential surface 18 in which the diameter is further reduced as advancing toward the tip end portion of the pipe joint body 1 is formed on the radially inward side of a root portion of the tubular screwing portion 1A, and a tip-expanded annular groove 19 into which the basal end side of the fitting tubular portion 3B is fitted is formed between the outer circumferential surface 18 of the small-diameter tubular portion 1a and the inner circumferential surface 9 of the tubular screwing portion 1A.

(75) In the tip end portion of the small-diameter tubular portion 1a, the tip end side of the small-diameter tubular portion 1a is deformed and projected in the radial inward direction (toward the fluid passage), thereby forming a cut-shaped deformation preventing portion 21 for preventing the fluid from entering and staying.

(76) In the case of Embodiment 2, the union nut 2 is screw-advanced by being screwed with the tubular screwing portion 1A of the pipe joint body 1, and turned in the fastening direction. Then, the tip-end side outer circumferential surface (outer circumferential surface of the tip-contracted press-contact portion 4a) of the tube end portion 4C is pressed in the direction of the axis Y by the pressing portion 12b of the union nut 2.

(77) This causes the basal end side of the fitting tubular portion 3B of the inner ring 3 to be press-inserted into the annular groove 19 of the pipe joint body 1, and the tip-contracted outer circumferential surface 18 (an example of the seal configuring portion) of the pipe joint body 1 and the tip-contracted inner circumferential surface 20 (an example of the seal element portion) of the inner ring 3 to be butted against and press-contacted with each other, and the third seal portion (an example of the inner seal portion) S3 is configured.

(78) In order to enable the third seal portion S3 to perfectly function, i.e., in order to prevent the basal end side of the fitting tubular portion 3B from being butted against the bottom surface of the annular groove 19 to cause the tip-contracted inner circumferential surface 20 to enter a state where the inner circumferential surface is not press-contacted with the outer circumferential surface 18 of the tubular screwing portion 1A, the end surface of the basal end side of the fitting tubular portion 3B is formed into a cut-shaped butting avoiding portion 22.

(79) The connection of the tube 4 and the pipe joint body 1 by using the inner ring 3 of Embodiment 2 is similar to that in the configuration of Embodiment 1 shown in FIGS. 4 and 5 except the configuration of the third seal portion S3 (the inner seal portion). Therefore, the reference numerals in FIGS. 4 and 5 are used also in FIGS. 9 and 10, and their description is omitted.

OTHER EMBODIMENTS

(80) It is matter of course that the connection of the tube 4 into which the inner ring 3 is press-inserted is not limited to the pipe-connecting device A (pipe joint) of Embodiments 1 and 2. A connection with the pipe-connecting device A (pipe joint) having another mode may be performed without departing from the invention. It is matter of course that the tube 4 into which the inner ring 3 is press-inserted may be connected to a pipe-connecting device configured by a fluid apparatus such as a pump or a valve.

DESCRIPTION OF REFERENCE NUMERALS

(81) 1a seal configuring portion 3A inner ring body 3G outer circumferential portion 3a outer-circumferential flared surface 3b maximum-diameter portion 3f flared portion 4 tube 4C end portion 14, 15 seal element portion A pipe-connecting device D outer diameter of tube P axis (axis of inner ring) S3, S4 inner seal portion e1 first place e2 second place e3 third place m seal configuring portion