JP2005140138A - Pipe joint structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely prevent the floating of a lock ring from an outer periphery of a spigot when the tensile force is acted on a joint part and to surely prevent the separation by the lock ring of a narrow axial width even when a length of a clearance between an inner face of a socket and an outer face of the spigot is changed to some degree. <P>SOLUTION: A part kept into contact with an accommodation groove 7, of the lock ring 8 is taper faces 18a, 18b, inclination angles θ1, θ2 of the taper faces are changed in accordance with a radial length L from a surface of the spigot 5 to the contact part, and the component force F1 in the direction perpendicular to the taper faces 18a, 18b, of the separation preventing force against the separation force added to the joint part is passed through an opening side of the socket 3 with respect to a contact point 15 with the outer periphery of the spigot 5 at the lock ring 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pipe joint structure.

As a joint structure of a pipe having an expansion / contraction function and a detachment preventing function, that is, an earthquake resistance function, a joint as shown in FIG. 7 is known.
The seismic joint 1 shown in FIG. 7 is configured by inserting an insertion port 5 in the other tube 4 into a receiving port 3 in one tube 2. A seal material pressure contact surface 6 and a lock ring receiving groove 7 are formed on the inner surface of the receiving port 3 from the opening side of the receiving port 3 toward the inner side of the tube axis direction receiving port. The lock ring 8 divided by 10% in the circumferential direction is accommodated, and the insertion port 5 is inserted until the insertion projection 9 passes through the inside of the lock ring 8 and reaches the back side of the receiving port 3.

  A resin backup ring 10, a rubber seal material 11, a split ring 12 that can come into contact with the seal material 11, and a press ring 13 that can press the split ring 12 are arranged in advance on the outer periphery of the insertion slot 5. The sealing material 11 is brought into contact with the sealing material pressure contact surface 6, the plurality of bolts 14 a implanted in the end surface of the receiving port 3 are passed through the plurality of round holes 13 a formed in the presser wheel 13, and the nut 14 b is screwed. Thus, the push ring 13 and the split ring 12 are pressed toward the back side of the receiving port 3, and the seal material 11 is compressed between the seal material pressure contact surface 6 and the outer periphery of the insertion port 5, thereby sealing the joint portion. In the state which provided the function, the receptacle 3 and the insertion slot 5 are mutually joined.

  When a large tensile force due to an earthquake or the like is applied to the earthquake-resistant joint 1 configured as described above, the insertion port 5 is indicated by a solid line from the state where it is inserted on the back side of the reception port 3 indicated by a virtual line in the figure. In this way, the insertion / projection function can be exhibited until the insertion projection 9 comes into contact with the lock ring 8, that is, when the insertion projection 3 comes out of the receptacle 3 only within a predetermined range. The function of preventing separation can be exhibited by engaging 9 with the lock ring 8 from the back side of the receiving port 3.

  By the way, in the seismic joint 1 as described above, the tensile force R for pulling out the insertion port 5 from the receiving port 3 is inserted into the lock ring 8 when a tensile force is applied to the joint part as shown in FIG. A detachment prevention force F acting from the mouth projection 9 and trying to prevent the insertion opening 5 from coming out of the receptacle 3 acts from the side surface 7 a on the receptacle opening side in the lock ring housing groove 7.

  At this time, since the line of action of the separation preventing force F and the tensile force R does not exist on the same straight line, a rotational force T in the clockwise direction is generated in the lock ring 8 as shown in the figure. When the acting tensile force is very large, as shown by the phantom line in the figure, the lock ring 8 divided by 10% in the circumferential direction has a contact point 15 between the side surface on the back side of the receiving port and the outer periphery of the insertion port. May rise from the outer periphery of the insertion slot 5 while being elastically deformed around the center of rotation. As described above, if the lock ring 8 is lifted from the outer periphery of the insertion slot 5, there is a possibility that an appropriate detachment preventing function cannot be exhibited.

  Therefore, as shown in FIG. 9, the cross-sectional shape of the lock ring 8 is such that the bottom side 8 c in contact with the outer periphery of the insertion port 5 is a long side, and the side surface of the lock ring 8 on the receiving opening side and the receiving port back side is tapered. It is formed in an isosceles trapezoidal shape having a surface 8a and a tapered surface 8b, and when the tensile force is applied to the joint portion, the taper surface 8a generates a component force F1 of the separation preventing force F with respect to the outer surface of the insertion port. The lock ring 8 is prevented from floating from the outer periphery of the insertion slot 5 by this component force F1 (Patent Document 1).

  That is, the acting line 17 of the component force F1 in the direction perpendicular to the tapered surface 8a in the tube shaft direction disengagement preventing force F acting on the lock ring 8 from the lock ring housing groove 7 is as shown in FIG. For example, when the action line 17 passes a distance d away from the contact point 15 with respect to the contact point 15 which is the center of rotation, the rotational force T = F1 · d is applied to the lock ring 8. Acts to prevent the lock ring from lifting up.

Note that the component force F2 in the direction along the tapered surface 8a in the separation preventing force F at this time does not significantly affect the lifting of the lock ring 8 from the outer periphery of the insertion port 5.
JP 2002-5361 A

  By the way, the direction of the component force F1 generated on the taper surface 8a of the lock ring 8 is determined by the inclination angle θ of the taper surface 8a. Therefore, depending on the distance L between the inner surface of the receiving port 3 and the outer surface of the insertion port 5, the above-mentioned lift prevention condition is satisfied. There are times when it stops.

  For example, as shown in FIG. 10, when the inner diameter of the receiving port is a plus maximum tolerance value and the outer diameter of the insertion port is a minus minimum tolerance value, the above-mentioned distance d is maximized, so that the action line 17 of the component force F1 is As shown in FIG. 10, it may pass through the receiving port deeper side than the contact 15 that becomes the rotation center of the lock ring, and may rise from the outer periphery of the insertion port 5.

  Therefore, the length of the bottom side of the lock ring 8 needs to be sufficiently large so that this does not occur. Depending on the tolerance due to the tube diameter, the lock ring 8 having a wider axial width than necessary is used. There was a problem that it might be necessary.

  In particular, as shown in FIG. 11, in the case of a lock ring having a shape in which the width M of the base 8c is narrow and the height is high, and the cross section is high in the vertical direction, the component force F1 generated on the tapered surface 8a on the side surface of the receiving opening is inserted. Since the distance between the outer surface of the mouth and the inner surface of the mouth is slightly changed and the position of the contact 15 is easily exceeded to the back side of the tube mouth, the axial width M of the lock ring can be prevented. There is a problem that the size of parts and the size of joints cannot be reduced.

  Therefore, the present invention solves such problems and can reliably prevent the lock ring from floating from the outer periphery of the insertion port when a tensile force is applied to the joint portion. An object of the present invention is to make it possible to reliably prevent detachment with a narrow lock ring even if the gap distance between them changes slightly.

  In order to solve the above-mentioned problem, the present invention is configured such that a lock ring is housed in a lock ring housing groove formed on an inner surface of a receiving port of one tube, and a tip of an insertion port of the other tube inserted into the receiving port. An outer peripheral protrusion formed on the outer periphery is configured to be able to engage with the receiving port back side portion of the lock ring, and a receiving port opening side portion of the lock ring is configured to be able to engage with the lock ring receiving groove. Thus, in the joint structure of the pipe capable of preventing the insertion port from being detached from the receiving port, a portion of the lock ring that contacts the lock ring receiving groove is pointed forward with respect to the opening side of the receiving port. It is a tapered surface that becomes a ball-like shape, and an inclination angle of the tapered surface with respect to the insertion surface changes according to a radial distance from the insertion surface to the contacting portion, and from the receiving port. Above When a detachment preventing force in the tube axis direction that prevents the mouth from detaching is transmitted from the lock ring housing groove to the lock ring via the tapered surface, the lock opening with respect to the receiving opening side portion of the lock ring. Regardless of the radial distance from the outer surface of the insertion port at the position where the lock ring receiving groove is engaged, the line of action of the component force in the direction perpendicular to the tapered surface of the separation preventing force is the back side of the receiving port in the lock ring. It is characterized by passing through the opening side of the receiving port rather than the contact point between the portion and the outer periphery of the insertion port.

  According to such a configuration, the action line of the component force in the direction perpendicular to the taper surface in the tube shaft direction separation preventing force acting on the lock ring increases the distance between the inner surface of the receiving port and the outer surface of the insertion port. However, due to the gradually decreasing inclination angle, the direction of the component force generated by the inclined surface is the receiving opening side, so that the line of action of the component force passes from the contact point to the receiving opening side. Even with a lock ring having a small directional width, the function of preventing separation is surely exhibited.

Next, the pipe joint structure of the present invention will be described.
In the first to fourth embodiments described below, the same reference numerals as those used in FIGS. 7 to 11 are given to the same parts as those already described in the conventional pipe joint structure. Detailed description thereof is omitted.
(Embodiment 1)
As shown in FIG. 1, an insertion port 5 in the other tube 4 is inserted into the receiving port 3 in one tube 2, and an insertion projection that is an outer peripheral projection on the outer periphery of the distal end side of the insertion port 5. 9 is formed.

On the inner surface of the receiving port 3, a lock ring receiving groove 7 having a U-shaped cross section and opening to the inner surface of the receiving port 3 is formed as shown in the figure.
The lock ring housing groove 7 accommodates a lock ring 8 which is divided by 10% in the circumferential direction. The lock ring 8 has an opening side surface 8a which is a receiving opening side and a back side surface 8b which is a receiving back side. Are formed so as to be perpendicular to the outer periphery of the insertion opening 5, and the back side surface 8 b is formed so as to be in surface contact with the end face of the insertion opening protrusion 9 on the receiving opening side. In addition, a portion corresponding to the opening edge 7a of the lock ring receiving groove 7 on the opening side surface 8a of the lock ring 8 is a ring-side tapered surface that has a tapered shape with respect to the receiving opening side, and has an inclination angle. Are formed so that the opening edge 7a and the ring-side tapered surfaces 18a, 18b are in point (line) contact.

Here, the inclination angle θ1 of the ring-side taper surface 18a is set such that the distance from the inner surface of the receiving port to the outer surface of the insertion port is L, and the distance from the opening edge 7a of the lock ring housing groove 7 to the contact point 15 is M.
M> Ltan θ1 (A)
The angle θ1 is set so as to satisfy the above condition.

On the other hand, if the taper surface has an angle θ1, only the axial width m {= [M + (L−f) cot θ1] (f is the height of the vertical portion)} and the relationship between θ1 and L, M = Ltan θ1 ... (B)
There can be a point.

Therefore, with the point of (B) as the boundary, the inclination angle θ2 of the other inclined surface 18b is set to Ltanθ1> Ltanθ2 and M> Ltanθ2
Is set so as to satisfy the above.

  In other words, the tapered surfaces 18a and 18b are such that the inclination angle θ becomes smaller as the distance L at (D1−D2) / 2 = L becomes larger when the inner diameter of the receiving port is D1 and the outer diameter of the insertion tube is D2. In the illustrated example, the inclination angle θ2 of the second-stage inclined surface 18b corresponding to the large value L is smaller than the inclination angle θ1 of the first-stage inclined surface 18a corresponding to the small value L. A component force F1 in a direction perpendicular to the inclined surfaces 18a and 18b, which is generated when the opening edge 7a of the lock ring receiving groove 7 is in contact with the inclined surfaces 18a and 18b, is inserted into the lock ring 8 and the inclined surfaces 18a and 18b. Before passing through the contact 15 with the outer surface of the mouth, it changes to the receiving opening side.

  In the joint portion having such a structure, when a large tensile force is applied due to an earthquake or the like, separation prevention that acts on the ring side taper surfaces 18a and 18b of the lock ring 8 from the groove side taper surface 7b of the lock ring housing groove 7 is performed. The force F is related to the distance L from the inner surface of the receiving port to the outer surface of the insertion port. The component force F1 in the direction perpendicular to the tapered surfaces 18a and 18b always passes through the receiving port opening side from the contact point 15. Accordingly, the rotational force T = F1 · d in the direction in which the lock ring 18 does not float from the outer periphery of the insertion port 5, that is, the direction in which the lock ring 18 is pressed against the outer periphery of the insertion port 5, is rotated about the contact point 15. Acts as

  Therefore, when the groove-side tapered surface 7b is formed on the side surface 7a on the receiving opening side of the lock ring housing groove 7 and the ring-side tapered surface 18c is also formed on the opening-side side surface 18a of the lock ring 18, The lock ring 18 having a small axial width can be obtained by adjusting the inclination angle θ with respect to the distance L between the inner surface of the receiving port and the outer surface of the insertion port based on the inequality (A).

(Embodiment 2)
In the pipe joint structure described in the second embodiment, the inclined surface of the lock ring 8 in the pipe joint structure described in the first embodiment is changed in three stages as shown in FIG. Since the change amount of θ1 to θ3 is small and can be formed in multiple stages, it is suitable when the value of L, that is, the tolerance is large.
(Embodiment 3)
In the pipe joint structure described in the third embodiment, as shown in FIG. 4, the change in the inclined surface of the lock ring 8 in the pipe joint structure described in the second embodiment is further changed into a curved surface. In addition to a simple circular curve, it is a quadratic curve or the like.

Also in this case, it is possible to obtain a fine pull-out prevention force against the change in L and to prevent the lock ring from falling.
(Embodiment 4)
In the pipe joint structure described in the fourth embodiment, as shown in FIG. 5, the change in the inclined surface of the lock ring 8 in the pipe joint structure described in the third embodiment is a combination of a straight line and a curved surface. .

Also in this case, it is possible to obtain a fine pull-out prevention force against the change in L and to prevent the lock ring from falling.
In the above embodiment, the side surface 7a of the lock ring housing groove 7 is perpendicular to the tube axis. However, as shown in FIG. It can carry out similarly about what inclined to the direction.

It is sectional drawing which shows the effect | action of the joint structure of the pipe | tube of Embodiment 1 of this invention. It is sectional drawing which shows the other effect | action of the joint structure of the pipe | tube of Embodiment 1 of this invention. It is sectional drawing which shows the joint structure of the pipe | tube of Embodiment 2 of this invention. It is sectional drawing which shows the joint structure of the pipe | tube of Embodiment 3 of this invention. It is sectional drawing which shows the joint structure of the pipe | tube of Embodiment 4 of this invention. It is sectional drawing which shows the other structural example in each embodiment. It is sectional drawing which shows the coupling part of the conventional pipe | tube which has an earthquake resistance function. It is a figure which shows the state which the rotational force which raises this lock ring from the outer periphery of an insertion port is acting on the lock ring in the conventional joint structure of a pipe | tube. FIG. 9 is a diagram showing a pipe joint structure for preventing the generation of the rotational force shown in FIG. 8 in the conventional technique. In the joint structure of the pipe | tube in a prior art, it is a figure which shows the state in which the rotational force which lifts a lock ring from the outer periphery of an insertion slot is acting on the lock ring. It is explanatory drawing which shows the state in which the rotational force which floats on the lock ring in the prior art is acting.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Earthquake-resistant joint 2 One pipe 3 Receptacle 4 The other pipe 5 Insertion 7 Lock ring accommodation groove 7a Receptacle opening side surface 8 Lock ring 9 Insertion protrusion 15 Contact (rotation center)
17 Action Line 18a Inclined Surface 18b Inclined Surface 18c Inclined Surface 18d Curved Surface F Detachment Prevention Force θ Inclination Angle

Claims (4)

A lock ring is housed in a lock ring housing groove formed on the inner surface of the receiving port of one tube, and an outer peripheral protrusion formed on the outer periphery of the distal end of the insertion port of the other tube inserted into the receiving port is the lock. The insertion port is configured to be able to engage with the receiving port back side portion of the ring, and the insertion port is separated from the receiving port by configuring the receiving port opening side portion of the lock ring to be able to engage with the lock ring receiving groove. In the pipe joint structure that can be prevented, the portion of the lock ring that contacts the lock ring receiving groove is a tapered surface that is tapered toward the opening side of the receiving port, and An angle of inclination of the tapered surface with respect to the insertion surface is changed according to a radial distance from the insertion surface to the contacting portion, and the tube prevents the insertion port from being detached from the receiving port. Axial The insertion opening at a position where the lock ring receiving groove contacts the receiving opening opening side portion of the lock ring when a disengagement preventing force is transmitted from the lock ring receiving groove to the lock ring via the tapered surface. Regardless of the radial distance from the outer surface, the line of action of the component force in the direction perpendicular to the taper surface of the detachment preventing force is more than the contact point between the back side of the lock port and the outer periphery of the insertion port. A pipe joint structure characterized by passing through the opening side of the receiving port. In the pipe joint structure according to claim 1, as the radial distance from the insertion surface of the tapered surface of the lock ring to the portion in contact with the lock ring storage groove increases, the inclination angle of the tapered surface decreases stepwise. Pipe joint structure. The inclination angle of the taper surface decreases steplessly as the radial distance from the insertion surface of the taper surface of the lock ring in the pipe joint structure according to claim 1 to the portion in contact with the lock ring storage groove increases. Pipe joint structure with a smooth curved surface. 3. A pipe joint structure in which the inclined surface of the tapered surface of the lock ring in the pipe joint structure of claim 2 is a combination of a linearly inclined surface that changes stepwise and a smooth curved surface that changes stepwise. .

Images