JP5464756B2 - Pipe fitting - Google Patents

Description

  The present invention relates to a pipe joint.

  In recent years, a heat pump type hot water supply apparatus has become widespread as a clean hot water supply system in consideration of the global environment. The heat pump type hot water supply apparatus includes a heat pump unit that incorporates a refrigerant circuit that generates hot water by a refrigeration cycle, and a water storage unit that stores the hot water generated by the heat pump unit. In addition, in the heat pump hot water supply system, on-site installation work, communication piping for circulating hot water between the heat pump unit and the water storage unit, and communication for supplying hot water from the water storage unit to hot water use equipment such as a bathtub. Pipes are routed and connected to each unit and hot water equipment.

  In general, a pipe joint is used to connect a communication pipe to each unit or hot water utilization equipment. As a conventional pipe joint, there exists a thing described in patent document 1, for example. As shown in FIG. 13, this pipe joint is connected to a joint body 102 having an inner cylinder sleeve 101 on which a pipe is sheathed, an O-ring 103 fitted on the inner cylinder sleeve 101, and the joint body 102, An outer cylinder sleeve 105 having a tapered inner surface 104 that decreases in diameter toward the tube insertion port, and a C-shaped lock ring 107 in which an inner peripheral blade portion 106 that bites into the tube is formed on the inner peripheral surface.

  When the end of the pipe is inserted into the space S between the outer sleeve 105 and the inner sleeve 101 of the pipe joint, the O-ring 103 is pressed against the inner peripheral surface of the pipe, and the lock ring 107 is connected to the pipe. It bites into the outer peripheral surface of the tube and the tube is prevented from coming off. In particular, when the pipe moves in the direction of being pulled out from the pipe joint, the lock ring 103 is reduced in diameter by the tapered inner surface 104 and deeply bites into the outer peripheral surface of the pipe, so that the pipe is more reliably prevented from coming off.

JP 2010-249166 A

  In order to facilitate the insertion of the pipe into the pipe joint and to securely connect the pipe to the pipe joint, it is recommended to chamfer the outer peripheral edge of the pipe in advance. However, since such chamfering work is performed at the construction site of piping, the operator may inadvertently forget it. If a pipe that has not been chamfered is inserted into a pipe joint, the outer peripheral edge of the pipe may be caught in the middle, and the pipe may not be inserted into the pipe joint until the end. If the pipe is connected in an incomplete state with respect to the pipe joint, a sufficient seal is not achieved, which causes liquid leakage.

  This invention is made | formed in view of such a situation, and it aims at providing the pipe joint which can prevent the connection of an incomplete pipe | tube.

  A pipe joint according to a first aspect of the present invention includes an outer cylinder body into which a pipe is inserted on the distal end side in the axial direction, and a pipe that is provided on the inner peripheral surface of the outer cylinder body and is inserted into the outer cylinder body A holding ring that engages with the outer peripheral surface of the tube, the inner diameter of the axial end of the holding ring is smaller than the outer diameter of the tube, and the end when the outer peripheral edge of the tube is chamfered It is characterized by being formed larger than the outer diameter of the edge.

  According to this configuration, when the outer peripheral edge of the tube is not chamfered, the outer peripheral edge of the tube interferes with the inner peripheral edge of the holding ring, and thus the tube cannot be inserted. Therefore, an inappropriate pipe connection can be prevented.

The said structure WHEREIN: It is preferable that the dimension difference of the internal diameter of the axial direction front-end | tip of the said holding | maintenance ring and the outer diameter of a pipe | tube is set within the range of 2.0%-20.0% of the outer diameter of the said pipe | tube.
Generally, the dimension of the chamfering applied to the outer peripheral edge of the pipe (the total dimension in the diameter direction) is in the range of 2.0% to 20.0% of the outer diameter of the pipe. Therefore, by setting the dimensional difference between the inner diameter of the axial end of the retaining ring and the outer diameter of the pipe within the above range, the pipe can be chamfered without difficulty.

  A pipe joint according to a second aspect of the present invention includes an inner cylinder into which a distal end side in the axial direction is inserted into a pipe, and an inner circumference of a pipe that is provided on the outer circumferential surface of the inner cylinder and into which the inner cylinder is inserted. A retaining ring that engages with the surface, the outer diameter of the axially leading end of the retaining ring is larger than the inner diameter of the tube, and the inner edge of the tube is chamfered It is characterized by being formed smaller than the inner diameter of.

  According to this configuration, when the inner peripheral end of the tube is not chamfered, the inner peripheral end edge of the tube interferes with the outer peripheral end edge of the holding ring, and thus the tube cannot be inserted. Therefore, an inappropriate pipe connection can be prevented.

The said structure WHEREIN: It is preferable that the dimensional difference of the outer diameter of the axial direction front end edge of the said holding | maintenance ring and the internal diameter of a pipe | tube is set in the range of 2.0%-20.0% of the internal diameter of the said pipe | tube.
Generally, the dimension of the chamfering applied to the inner peripheral edge of the pipe (the total dimension in the diameter direction) is in the range of 2.0% to 20.0% of the outer diameter of the pipe. Therefore, by setting the dimensional difference between the inner diameter of the axial end of the retaining ring and the outer diameter of the pipe within the above range, the pipe can be chamfered without difficulty.

  According to the present invention, it is not possible to insert a pipe that has not been chamfered into a pipe joint, so that incomplete pipe connection can be prevented.

It is a perspective view which shows the pipe joint which concerns on the 1st Embodiment of this invention. It is sectional drawing of the pipe joint shown by FIG. It is sectional drawing which expands and shows the mounting part of the elastic seal member and holding ring in a pipe joint. (A) is sectional drawing of a retaining ring, (b) is a front view of a retaining ring. It is sectional drawing which shows the dimensional relationship between a holding | maintenance ring and a pipe | tube. It is sectional drawing which shows the state which inserts the pipe | tube in which the chamfering was given to a pipe joint. It is sectional drawing which shows the state which inserts the pipe | tube which has not been chamfered into a pipe joint. It is sectional drawing of the pipe joint which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows the dimensional relationship between a holding | maintenance ring and a pipe | tube. It is sectional drawing which shows the state which inserts the pipe | tube with which chamfering is not given to the pipe joint which concerns on a comparative example. It is sectional drawing which shows the dimensional relationship of the holding | maintenance ring and pipe in the pipe joint which concerns on the 3rd Embodiment of this invention. (A) is sectional drawing of a retaining ring, (b) is a front view of a retaining ring. It is sectional drawing of the pipe joint which concerns on a prior art.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
<< First Embodiment >>
FIG. 1 is a perspective view showing a pipe joint 10 according to a first embodiment of the present invention.
The pipe joint 10 according to the present embodiment is used to connect a pipe P through which a fluid such as a liquid or a gas flows and various devices U using the fluid. Connected to the end of the tube P, the base end in the axial direction is connected to the device U. Therefore, an insertion port 11 for inserting the pipe P is formed on the distal end side of the pipe joint 10 in the axial direction, and on the proximal end side in the axial direction, the end of the pipe (connected portion) U1 on the equipment U side. A nut 16 as a screw cylinder is provided to be screwed into the provided male screw.

In addition, the pipe joint 10 of this Embodiment is mainly for connection with the apparatus P and the pipe P which handles liquids, such as water, seawater, a chemical | medical agent, and brine which do not change a phase mainly in normal temperature (for example, 5 to 35 degreeC). Is preferably used. In particular, it is suitably used for connection between a heat source unit and piping in a hot water supply device, an air conditioner, a floor heating device, or the like. Further, the pipe P is a hard resin pipe such as a cross-linked polyethylene pipe or a boribden pipe having good corrosion resistance and heat resistance, or a metal reinforced resin pipe such as a three-layer pipe in which the inner and outer surfaces of a metal pipe such as aluminum are coated with a resin material. Is used. Since the hard resin pipe and the three-layer pipe have high heat resistance, they are preferably used in a system that generates very high temperature hot water of 90 ° C. or higher, such as a heat source unit using a CO ₂ refrigerant.

FIG. 2 is a cross-sectional view of the pipe joint 10 shown in FIG. In the pipe joint 10 shown in this figure, the tip end to which the pipe P is connected is shown on the left side in the figure, and the base end part connected to the connected portion U1 of the device U is shown on the right side in the figure. Yes.
The pipe joint 10 is mainly composed of an inner cylinder body 14, an outer cylinder body 15, and a nut 16. The inner cylinder body 14, the outer cylinder body 15, and the nut 16 are made of a metal material such as lead-free bronze or gun metal, or a hard resin material. The inner cylindrical body 14 is formed in a cylindrical shape, and an annular notch groove 17 is formed on the outer peripheral surface of the distal end portion thereof. An elastic force which will be described later is provided on the base end side (right side in FIG. 2) from the notch groove 17. An annular mounting groove (seal mounting portion) 18 for mounting the seal member 36 is formed. The inner peripheral surface of the base end portion of the inner cylindrical body 14 is formed on a tapered surface 19 whose inner diameter is increased toward the base end side.

  An annular first protrusion 21 that protrudes radially outward is formed at the proximal end of the inner cylindrical body 14. In addition, at a position adjacent to the distal end side (the left side in FIG. 2) of the first protrusion 21, an annular second protrusion protruding outward in the radial direction with a protrusion amount smaller than that of the first protrusion 21. A portion 22 is formed.

  The outer cylinder 15 is formed in a cylindrical shape, and is disposed concentrically with the inner cylinder 14 on the radially outer side of the inner cylinder 14. A space (hereinafter also referred to as “insertion space”) S in which the pipe P can be inserted is formed between the inner peripheral surface of the outer cylindrical body 15 and the outer peripheral surface of the inner cylindrical body 14. . The outer peripheral surface of the distal end portion of the outer cylindrical body 15 is formed as a tapered surface 24 whose outer diameter increases toward the proximal end side. An annular holding recess 25 for accommodating a holding ring 42 described later is formed on the inner peripheral surface of the distal end portion of the outer cylindrical body 15. The holding recess 25 is disposed at a position overlapping the radially outer side of the notch groove 17 and the mounting groove 18 formed in the inner cylinder 14.

  The nut (screw cylinder) 16 is formed integrally with the base end portion of the outer cylinder body 15. That is, the nut 16 and the outer cylindrical body 15 are configured by a single component by machining one material. The outer peripheral surface 27 of the nut 16 is formed in a hexagonal shape into which a tool such as a spanner can be fitted, and a female screw 28 is formed on the inner peripheral surface. In addition, an annular third protrusion 29 that protrudes radially inward is formed on the tip end side of the nut 16. In addition, the screw cylinder 16 can also be made into the form which has an external thread in an outer peripheral surface according to the shape of the to-be-connected location U1 at the apparatus U side.

  The inner cylindrical body 14 is inserted into the nut 16 from the base end side (right side in FIG. 2) of the nut 16, and further protrudes toward the distal end side (left side in FIG. 2) from the nut 16 to the inside of the outer cylindrical body 15. Be placed. At this time, the first protrusion 21 of the inner cylinder 14 abuts against the third protrusion 29 of the nut 16 in the axial direction, thereby restricting the movement of the inner cylinder 14 relative to the nut 16 toward the tip side. Yes. Therefore, the first protrusion 21 of the inner cylinder 14 and the third protrusion 29 of the nut 16 constitute a position restricting part 31 for restricting the movement of the inner cylinder 14 relative to the nut 16 toward the tip side. doing.

In addition, the 2nd protrusion part 22 formed in the inner cylinder 14 has a function as a stopper which sets the insertion limit of the pipe | tube P with respect to the insertion space S. As shown in FIG.
Further, an annular packing 33 is provided inside the nut 16, and this packing 33 is sandwiched between the base end surface of the inner cylinder 14 and the tip end surface of the connected portion U <b> 1 on the device U side. , Preventing fluid leakage between the two. Further, when the pipe joint 10 is not used or when only the pipe P is connected to the pipe joint 10, the movement of the inner cylinder body 14 relative to the nut 16 is not restricted. A cap (not shown) that restricts movement of the body 14 toward the proximal end is attached.

FIG. 3 is an enlarged cross-sectional view showing a mounting portion of the elastic seal member 36 and the holding ring 42 in the pipe joint 10.
An annular elastic seal member 36 is mounted in the mounting groove 18 formed in the inner cylindrical body 14. The elastic seal member 36 is made of an elastically deformable material, for example, nitrile rubber, ethylene propylene rubber, silicon rubber, fluorine rubber, or the like.

  On the outer peripheral surface of the elastic seal member 36, two annular seal portions 38a and 38b bulging in an arc shape radially outward are formed side by side in the axial direction. The seal portions 38 a and 38 b protrude outward in the radial direction from the inner peripheral surface of the inner cylindrical body 14 in a state of being inserted into the mounting groove 18. These seal portions 38a and 38b have a function of preventing fluid leakage between the inner cylindrical body 14 and the pipe P by being in close contact with the inner peripheral surface of the pipe P inserted into the insertion space S. doing.

  A flat surface 40 substantially parallel to the central axis O is formed on the base end side (the right side in FIG. 3) of the elastic seal member 36. The flat surface 40 serves as a mark indicating the mounting direction of the elastic seal member 36 with respect to the mounting groove 18. Specifically, in the present embodiment, the elastic seal member 36 is mounted in the mounting groove 18 so that the flat surface 40 is positioned on the proximal end side.

  The elastic seal member 36 of the present embodiment has a configuration in which two seal portions 38a and 38b are integrally provided in the axial direction, but the two seal portions 38a and 38b are formed separately and are mutually connected. It may be an independent configuration. For example, the elastic seal member 36 may be configured by arranging two O-rings or the like constituting one seal portion side by side in the axial direction. Furthermore, there may be only one seal portion. Moreover, the elastic seal member 36 may be provided in two or more places at intervals in the axial direction.

FIG. 4A is a cross-sectional view of the retaining ring 42, and FIG. 4B is a front view of the retaining ring 42.
As shown in FIGS. 3 and 4, a holding ring 42 is accommodated in the holding recess 25 formed on the inner peripheral surface of the outer cylinder 15. The holding ring 42 is formed in a C-shape with a circumferential portion 43 missing, and the radial dimension can be reduced by elastically deforming the gap between the missing portions 43. . Further, the holding ring 42 can be attached to the holding recess 25 by being inserted from the front end opening of the outer cylindrical body 15 with the radial dimension reduced. The holding ring 42 is inserted from the front end opening of the outer cylinder 15 and is not only elastically deformed in the diameter reducing direction but also slightly plastically deformed when mounted in the holding recess 25. Therefore, there is a change in the diameter of the retaining ring 42 before and after mounting on the outer cylinder 15.

  As shown in FIG. 3, a first claw portion (first holding portion) 46 that protrudes inward in the radial direction is formed on the tip end side in the axial direction (the left end side in FIG. 2) on the inner peripheral surface of the holding ring 42. In addition, a second claw portion (second holding portion) 45 protruding inward in the radial direction is formed on the proximal end side in the axial direction (the right end side in FIG. 2). The first claw portion 46 and the second claw portion 45 have a function of holding the pipe P firmly by being pressed against the outer peripheral surface of the pipe P by reducing the radial dimension of the holding ring 42. ing. The axial tip of the retaining ring 42 is formed on a flat surface 51 that is substantially perpendicular to the axial center, and the axial proximal end of the retaining ring 42 is also formed on a flat surface 58 that is substantially perpendicular to the axial center.

  A first inclined surface 49 is formed on the outer peripheral surface of the holding ring 42 on the distal end side in the axial direction so that the outer diameter increases toward the proximal end side (the right side in FIG. 3). Further, a second inclined surface 48 that is inclined so that the outer diameter increases toward the proximal end side is formed on the proximal end side with respect to the first inclined surface 49. Therefore, the first and second inclined surfaces 49 and 48 are formed so that the radial distance between the outer peripheral surface of the tube P inserted into the insertion space S becomes narrower toward the distal end side. Further, a first step surface 50 is formed between the first inclined surface 49 and the second inclined surface 48, and the first step surface 50 is formed substantially parallel to the central axis O.

  The first inclined surface 49 and the second inclined surface 48 are formed at substantially the same inclination angle. Further, the first inclined surface 49 and the second inclined surface 48 are arranged apart from each other in the axial direction with the first step surface 50 interposed therebetween. Note that the base end side of the outer peripheral surface of the retaining ring 42 further than the second inclined surface 48 is an inclined surface 52 whose outer diameter decreases toward the base end side. Since the outer diameter of the base end side of the holding ring 42 is reduced by the inclined surface 52, the holding ring 42 can be easily inserted from the distal end opening of the outer cylindrical body 15, and can be easily attached to the holding recess 25. become able to.

  The bottom surface of the holding recess 25 formed in the outer cylinder 15 has a third inclined surface 54 and a fourth inclined surface 53. The third inclined surface 54 is inclined at substantially the same angle as the first inclined surface 49 of the holding ring 42 and abuts on the first inclined surface 49. The fourth inclined surface 53 is inclined at substantially the same angle as the second inclined surface 48 of the holding ring 42 and abuts on the second inclined surface 48. A second step surface 55 substantially parallel to the central axis O is formed between the third inclined surface 54 and the fourth inclined surface 53.

  The holding ring 42 is elastically deformed and plastically deformed in the diameter reducing direction when inserted from the distal end opening of the outer cylinder 15, and slightly elastically returns in the diameter expanding direction when disposed in the holding recess 25. At this time, a radial gap is formed between the first and second inclined surfaces 49 and 48 and the third and fourth inclined surfaces 54 and 53. When the pipe P is inserted into the insertion space S between the outer cylinder 15 and the inner cylinder 14, the radial dimension of the holding ring 42 is enlarged, and the first and second inclined surfaces 49, 48 are formed. It abuts on the third and fourth inclined surfaces 54 and 53.

  When force in a direction (arrow X) in which the pipe P is separated from the insertion space S is applied to the pipe P due to the pressure of the fluid flowing inside the pipe P, the holding ring 42 moves to the tip side together with the pipe P, and the first to first The fourth inclined surfaces 49, 48, 54, and 53 are pushed radially inward by the outer cylinder 15 to reduce the radial dimension. Then, by reducing the radial dimension of the retaining ring 42, the first claw portion 46 and the second claw portion 45 are more strongly pressed against the outer peripheral surface of the tube P, and the tube P is reliably detached from the insertion space S. Is prevented. In particular, since the holding ring 42 is pushed radially inward at two locations of the first and second inclined surfaces 49 and 48 on both sides in the axial direction, the entire range of the holding ring 42 in the axial direction is set around the circumference of the pipe P. Can be strongly pressed against the surface.

  Here, the first to fourth inclined surfaces 49, 48, 54, 53 constitute an action part that reduces the radial dimension of the holding ring 42 by the movement of the pipe P in the separation direction X, and this action part and the holding part The ring 42 constitutes a holding mechanism 47 that holds the pipe P inserted into the insertion space S. In addition, the action portion is a first action surface configured by a set of a first inclined surface 49 and a third inclined surface 54, and a second set of a second inclined surface 48 and a fourth inclined surface 53. It consists of a working surface.

  In addition, the inclined surface which comprises an action part does not need to be formed in both the outer cylinder 15 and the holding ring 42, and should just be formed in any one. For example, the action part may be constituted by only the first inclined surface (first action surface) 49 and the second inclined surface (second action surface) 48 formed in the holding ring 42, and in this case, the holding recess It is only necessary that a portion (for example, a corner) that contacts the first inclined surface 49 and the second inclined surface 48 be present on the bottom surface of 25. On the contrary, the action part may be constituted only by the third inclined surface (first action surface) 54 and the fourth inclined surface (second action surface) 53, and in this case, the outer peripheral surface of the holding ring 42 In addition, it is sufficient if there are portions (for example, corners) that are in contact with the third inclined surface 54 and the fourth inclined surface 53, respectively.

When the strength of the tube P deteriorates with long-term use, the tube P tends to be detached from the insertion space S. However, as described above, the holding ring 42 causes the tube P to move away from the insertion space S by the movement of the tube P in the direction X. Since the tube P is firmly held, the separation of the tube P is reliably prevented.
Further, the elastic seal member 36 is deteriorated by long-term use, and permanent set is generated as the elastic force is reduced. This permanent distortion causes a decrease in the surface pressure of the elastic seal member 36 with respect to the inner peripheral surface of the pipe P, which causes fluid leakage. In this embodiment, the second claw portion 45 of the holding ring 42 is disposed at a position facing the radially outer side of the elastic seal member 36 in this embodiment, so that the radial dimension of the holding ring 42 is reduced. When the second claw portion 45 is strongly pressed against the outer peripheral surface of the pipe P, the inner peripheral surface of the pipe P is strongly pressed against the elastic seal member 36, and the seal surface pressure by the elastic seal member 36 is increased. Therefore, even if permanent deformation occurs in the elastic seal member 36, the function of the elastic seal member 36 can be maintained.

  Further, the first claw portion 46 of the retaining ring 42 is disposed at a position facing the radially outer side of the cutout groove 17 of the inner cylindrical body 14. For this reason, when the radial dimension of the retaining ring 42 is reduced and the first claw portion 46 is strongly pressed against the outer peripheral surface of the pipe P, the inner peripheral surface of the pipe P is the edge (locking portion) 56 of the notch groove 17. The edge 56 bites into the inner peripheral surface of the pipe P and is locked. Thereby, the holding force of the pipe P by the holding ring 42 is increased, and the detachment of the pipe P from the insertion space S is more reliably prevented.

Although the pipe joint 10 demonstrated above inserts the pipe P in the insertion space S from the insertion port 11, it connects the pipe P and the apparatus U by screwing the nut 16 in the connection location U1 of the apparatus U. In this case, the pipe joint 10 may be connected to the pipe P first, or may be connected to the device U first.
In the former case, for example, as shown in FIG. 2, when the nut 16 is rotated for connection to the device U in a state where the pipe P is inserted into the insertion space S of the pipe joint 10, the nut 16 is integrally formed. The outer cylinder 15 is also rotated. On the other hand, the inner cylinder 14 is only restricted to move toward the tip by the position restricting portion 31 with respect to the nut 16 and the outer cylinder 15, and can rotate relative to the nut 16 and the outer cylinder 15. Therefore, the stopped state is maintained without being rotated with the rotation of the nut 16.

  Further, since the holding ring 42 pressed against the pipe P is only in contact with the bottom surface of the holding recess 25 of the outer cylinder 15, even if the outer cylinder 15 rotates with the nut 16, the holding ring 42. Does not slide along the bottom surface of the holding recess 25, and the pipe P is also kept stopped. Accordingly, only the outer cylinder 15 rotates together with the nut 16, and the pipe P is not kinked with the rotation of the nut 16, and the elastic seal member 36 is not excessively rubbed and damaged. Therefore, the sealing performance by the elastic seal member 36 can be suitably maintained.

  In the latter case, not only when the nut 16 of the pipe joint 10 is screwed into the connected portion U1 on the equipment U side, but also when the pipe P is inserted into the insertion space S of the pipe joint 10 thereafter, the pipe P The elastic seal member 36 is hardly damaged by rubbing against the pipe P. Therefore, the pipe P and the device U can be connected without any problem.

  The pipe joint 10 of the present embodiment is assembled by inserting the inner cylindrical body 14 from the proximal end side of the nut 16 toward the distal end side and arranging the inner cylindrical body 14 inside the outer cylindrical body 15. And the movement to the front end side of the inner cylinder 14 with respect to the nut 16 is restrict | limited by making the 3rd protrusion 29 of the nut 16 and the 1st protrusion 21 of the inner cylinder 14 contact | abut in an axial direction. The Therefore, it is not necessary to use a C-ring for retaining the inner cylinder 14 with respect to the nut 16, so that the pipe joint 22 can be assembled very easily and the number of parts can be reduced. Can be planned.

As shown in FIG. 3, the first and second inclined surfaces 49 and 48 formed in the holding ring 42 and the third and fourth inclined surfaces 54 and 53 formed in the holding recess 25 are both in between. First and second step surfaces 50 and 55 are interposed. This has the following advantages.
For example, if the first step surface 50 is omitted and the first inclined surface 49 is extended to the base end side as it is and continues to the second inclined surface 48, the first and second inclined surfaces 49, 48 are radially outward. The holding ring 42 is formed thicker in the radial direction. When the holding ring 42 is formed thick in the radial direction, there is a disadvantage that the weight increases and the rigidity becomes high, so that the mounting to the holding recess 25 becomes difficult. Similarly, when the second step surface 55 of the holding recess 25 is omitted and the third inclined surface 54 is extended as it is to the base end side and is continued to the fourth inclined surface 53, the holding recess 25 is moved radially outward. It will be deeply formed. Accordingly, the radial dimension of the outer cylinder 15 must be increased, and the pipe joint 10 is increased in size. When the holding recess 25 is deepened, the holding ring 42 must naturally be formed thicker in the radial direction.

In this regard, in the present embodiment, a first step surface 50 is formed between the first inclined surface 49 and the second inclined surface 48, and between the third inclined surface 54 and the fourth inclined surface 53. Since the second step surface 55 is formed, the holding ring 42 can be formed in a wide axial range without increasing the radial thickness of the holding ring 42 and without forming the holding recess 25 so deep. The tube P can be strongly pressed against the outer peripheral surface.
Note that the first and second step surfaces 50 and 55 are not limited to surfaces parallel to the central axis O of the pipe joint 10, but are more gentle than the first to fourth inclined surfaces 49, 48, 54, and 53. Thus, it is possible to use a surface inclined in the same direction as these or a surface inclined in the opposite direction to the first to fourth inclined surfaces 49, 48, 54, 53.

As shown in FIG. 5, a flat surface 51 that is substantially perpendicular to the axis is formed at the tip of the holding ring 42 in the axial direction. The inner diameter (the diameter of the inner peripheral edge 57 of the flat surface 51) Dci at the axial tip of the retaining ring 42 has the relationship of the following expression (1) with respect to the outer diameter Dpo of the pipe P.
Dci <Dpo (1)
The inner diameter Dci of the holding ring 42 is a dimension when the holding ring 42 is attached to the outer cylinder 15, and is different from the dimension of the holding ring 42 before being attached to the outer cylinder 15.

On the other hand, in the construction site of piping, it is common practice to form a chamfer 60 on the outer peripheral edge of the pipe P before connecting the pipe P to the pipe joint 10. The outer diameter of the outer peripheral edge 61 of the pipe P when the chamfer 60 is formed is (Dpo-2Co) when the dimension of the chamfer 60 is Co, and the relationship with the inner diameter Dci of the holding ring 42 is expressed by the following equation. (2) is set.
Dci> Dpo-2Co (2)

Therefore, from the above formulas (1) and (2), the inner diameter Dci of the retaining ring 42 is smaller than the outer diameter Dpo of the pipe, but the outer peripheral edge 61 of the pipe P when the pipe P is chamfered 60 is applied. It becomes a dimension larger than an outer diameter (Dpo-2Co) (refer following Formula (3)).
Dpo-2Co <Dci <Dpo (3)

  Here, the pipe joint 10 of the present embodiment and the pipe joint according to the comparative example shown in FIG. 10 will be described in comparison. In the pipe joint shown in FIG. 10, the flat surface 51 is not formed at the tip of the holding ring 42, and the inner diameter Dci of the holding ring 42 is larger than the outer diameter Dpo of the pipe P. For this reason, even if chamfering is not formed on the tube P, the tube P can be inserted radially inward of the retaining ring 42 by the inclination of the first claw portion 46 of the retaining ring 42. However, if the pipe P is not chamfered, the insertion end position where the pipe P is caught by the other claw portion 45 or the like during the insertion into the insertion space S and abuts against the second protrusion 22 (see FIG. 2). There is a high possibility that the pipe P will stop before reaching. If the pipe P stops halfway, the connection with the pipe joint 10 becomes insufficient, and there is a possibility that the retaining ring 42 cannot properly prevent the pipe P from being removed, or that the elastic seal member 36 does not sufficiently seal the pipe P. Further, if the tube P stops in a state of being locked to the first claw portion 46, it is difficult to pull out the tube C by the first claw portion 46 even if the tube P is pulled out for reworking.

On the other hand, in the case of the present embodiment, since the inner diameter Dci of the retaining ring 42 is smaller than the outer diameter Dpo of the pipe P, as shown in FIG. 7, if the pipe P is not chamfered, the retaining ring 42 is retained. The inner peripheral edge 57 of the ring 42 and the outer peripheral edge 61 ′ of the pipe P interfere with each other, and the pipe P cannot be inserted into the insertion space S. Therefore, as described above, the pipe P can be prevented from being connected to the pipe joint 10 in an insufficient state.
If the inner diameter dimension Dci of the axial end of the holding ring 42 is set as in the above formula (3), if the chamfer 60 is formed on the outer peripheral edge of the pipe P, the holding ring 42 is held as shown in FIG. The inner peripheral edge 57 of the ring 42 and the outer peripheral edge 61 of the pipe P do not interfere with each other, and the pipe P can be smoothly inserted to the insertion end position of the pipe joint 10. Can be connected.

As shown in FIG. 5, the dimension Co of the chamfer 60 formed on the outer peripheral edge of the pipe P is usually 1.0% to 10.0% of the outer diameter Dpo of the pipe P. In other words, the total dimension 2Co in the diameter direction of the chamfer 60 is set to 2.0% to 20.0% of the outer diameter Dpo of the pipe P. Therefore, it is recommended that the dimension of the inner diameter Dci at the tip of the holding ring 42 in the axial direction be formed in the range represented by the following formula (4) in consideration of the dimension Co of the chamfer 60.
0.80 Dpo <Dci <0.98 Dpo (4)

When the above formula (4) is satisfied, the dimensional difference between the inner diameter Dci of the retaining ring 42 and the outer diameter Dpo of the pipe P is in the range of 2.0% to 20.0% of the outer diameter Dpo of the pipe P. .
By setting the inner diameter Dci dimension of the holding ring 42 in this way, the pipe P can be inserted inside the holding ring 42 in the radial direction if the pipe P is chamfered 60 with a normal dimension. That is, it is not necessary to make a large chamfer 60 in order to insert the pipe P inside the holding ring 42 in the radial direction, and the chamfer 60 can be easily constructed on site.
In addition, in the construction site of piping, the operation | work which chamfers 60 to the pipe P using the special instrument called a "chamfering machine" is performed, and if this chamfering machine is used, the outer diameter Dpo of the pipe P will be carried out. The chamfer 60 having a dimension Co of about 1.0% to 10.0% can be easily formed.

<< Second Embodiment >>
FIG. 8 is a cross-sectional view of a pipe joint according to the second embodiment of the present invention, and FIG. 9 is a cross-sectional view showing a dimensional relationship between the retaining ring and the pipe.
The pipe joint 10 of the present embodiment is different from the pipe joint 10 of the first embodiment in the arrangement of the retaining ring 42 and the notch groove 17. Specifically, a holding recess 25 is formed on the outer peripheral surface of the inner cylindrical body 14 on the tip side of the mounting groove 18, and the holding ring 42 is accommodated in the holding recess 25. The holding ring 42 includes a first claw portion 46 and a second claw portion 45 on its outer peripheral surface, and the diameter of the holding ring 42 at the bottom surface of the holding recess 25 by the movement of the tube P in the direction X to be removed from the insertion space S. The radial dimension is enlarged by being pushed outward in the direction, and the first claw portion 46 and the second claw portion 45 are pressed against the inner peripheral surface of the pipe P so as to hold the pipe P firmly. Yes.

  A notch groove 17 is formed on the inner peripheral surface of the outer cylindrical body 15. The cutout groove 17 is formed at a position facing the radially outer side of the first claw portion 46 of the holding ring 42. For this reason, when the radial dimension of the retaining ring 42 is enlarged and the first claw portion 46 is strongly pressed against the inner peripheral surface of the pipe P, the outer peripheral surface of the pipe P is the edge (locking portion) 56 of the notch groove 17. The edge 56 bites into the inner peripheral surface of the pipe P and is locked. Thereby, the holding force of the pipe P by the holding ring 42 is increased, and the detachment of the pipe P from the insertion space S is more reliably prevented.

As shown in FIG. 9, the outer diameter Dco at the tip of the holding ring 42 in the axial direction has a relationship satisfying the following expression (5) with the inner diameter Dpi of the pipe P.
Dco> Dpi (5)

In the case of the present embodiment, it is recommended that a chamfer 62 is formed on the inner peripheral edge of the pipe P. If the dimension of the chamfer 62 is Ci, the inner diameter of the inner peripheral edge 63 of the pipe P is recommended. Is (Dpi + 2Ci), and the relationship with the outer diameter Dco of the retaining ring 42 is set as in the following equation (6).
Dco <Dpi + 2Ci (6)

Therefore, from the above formulas (5) and (6), the outer diameter Dco of the retaining ring 42 is larger than the inner diameter Dpi of the pipe P, but the inner peripheral edge of the pipe P when the pipe P is chamfered 62. The size is smaller than the inner diameter (Dpi + 2Ci) of 63 (see the following equation (7)).
Dpi <Dco <Dpi + 2Ci (7)

  With the above configuration, the outer peripheral edge 59 of the retaining ring 42 interferes with the inner peripheral edge of the pipe P even when trying to insert the pipe P that has not been chamfered 62 into the pipe joint 10, and the pipe P cannot be inserted. It is possible to prevent the pipe P and the pipe joint 10 from being connected in an insufficient state.

In addition, the dimension Ci of the chamfer 62 formed on the inner peripheral edge of the pipe P is normally 1.0% to 10.0% of the inner diameter Dpi of the pipe P. In other words, the total dimension 2Ci in the diameter direction of the chamfer 62 is set to 2.0% to 20.0% of the inner diameter Dpi of the pipe P. Therefore, it is recommended that the dimension of the outer diameter Dco at the tip of the holding ring 42 in the axial direction be formed within the range represented by the following formula (8) in consideration of the dimension Ci of the chamfer 62.
1.02 Dpi <Dco <1.20 Dpi (8)

When the above formula (8) is satisfied, the dimensional difference between the outer diameter Dco of the retaining ring 42 and the inner diameter Dpi of the pipe P is in the range of 2.0% to 20.0% of the inner diameter Dpi of the pipe P.
By setting the outer diameter Dco of the retaining ring 42 in this way, if the chamfer 62 is formed with a normal dimension with respect to the tube P, the tube P can be inserted radially outward of the retaining ring 42. . That is, there is no need to chamfer in order to insert the pipe P outside the holding ring 42 in the radial direction, and the chamfering 62 can be performed without difficulty in the field.

<< Third Embodiment >>
FIG. 11 is a cross-sectional view showing a dimensional relationship between a retaining ring and a tube in a pipe joint according to a third embodiment of the present invention, FIG. 12 (a) is a sectional view of the retaining ring, and FIG. It is a front view.
The retaining ring 42 of the first and second embodiments is formed in a C shape with a circumferential portion 43 (see FIG. 4) missing, but the retaining ring 42 of the present embodiment is missing. It is formed in an annular shape with no part.

Specifically, the retaining ring 42 protrudes from a radially inner end of the annular portion 42a, at least the outer peripheral side thereof being disposed substantially perpendicular to the central axis of the pipe joint 10, and the pipe joint 10 And a plurality of engaging portions 42b curved in an arc shape toward the base end side.
Further, the outer cylindrical body 15 according to the present embodiment is divided into a base end side member 15a and a front end side member 15b. The female screw 15a1 formed on the base end side member 15a and the front end side member 15b. The base end side member 15a and the front end side member 15b are connected by screwing the male screw 15b1 formed on the front end. The retaining ring 42 is attached to the outer cylinder 15 by sandwiching the outer peripheral side of the annular portion 42a between the proximal end side member 15a and the distal end side member 15b.

  In the present embodiment, the diameter Dci of the inner peripheral edge at the tip in the axial direction of the holding ring 42 is configured to satisfy the above-described formulas (1) to (4). Therefore, when the pipe P with the chamfered 60 is inserted into the insertion space S between the outer cylinder 15 and the inner cylinder 14, the locking portion 42b of the retaining ring 42 is elastically deformed toward the proximal end, Insertion of the tube P is allowed. Further, when a force in the direction of separating from the insertion space S (arrow X) acts on the tube P, the locking portion 42b of the holding ring 42 bites into the outer peripheral surface of the tube P, so that the tube P is detached from the insertion space S. Is reliably prevented.

  In addition, when trying to insert the pipe P not chamfered 60 into the insertion space S, the inner peripheral edge 57 at the tip in the axial direction of the holding ring 42 interferes with the outer peripheral edge of the pipe P. It becomes difficult to insert the tube P into the space S. Therefore, it is possible to prevent the pipe P from being connected to the pipe joint 10 in an insufficient state.

The present invention is not limited to the above-described embodiment, and can be appropriately changed within the scope of the invention described in the claims.
The retaining ring 42 of the first and second embodiments may be provided with only the first claw portion 46. Further, the holding ring 42 may be provided at a plurality of locations in the axial direction. Further, in the first embodiment, the inner peripheral side of the first claw portion 46 of the holding ring 42 is an inclined surface, but it may be a surface parallel to the axis. Similarly, in the second embodiment, the outer peripheral side of the first claw portion 46 of the retaining ring 42 may be a surface parallel to the axis instead of the inclined surface.

In the above embodiment, the chamfers 60 and 62 formed on the pipe P are tapered, but they may be rounded (convex arcuate surface) or arcuately concaved.
The pipe joint 10 of the present invention can be used to connect the pipe P and the equipment U that handle gas as well as liquid.
Also. The configurations of the outer cylinder 15, the inner cylinder 14, and the screw cylinder 16 of the pipe joint 10 are not limited to the above embodiment. For example, the outer cylinder 15 and the inner cylinder 14 may be integrally formed (or integrally connected), and the screw cylinder 16 may be connected to be relatively rotatable. Moreover, the inner cylinder 14 and the screw cylinder 16 may be integrally formed, and the outer cylinder 15 may be connected thereto.

10: Pipe joint 14: Inner cylinder 15: Outer cylinder 16: Nut (screw cylinder)
31: Position restricting part 36: Elastic sealing member 38a: Sealing part 38b: Sealing part 42: Holding ring 51: End face of holding ring 57: Inner peripheral edge of holding ring 59: Outer peripheral edge of holding ring 60: Chamfer 61 : Outer peripheral edge of pipe 62: Chamfer 63: Inner peripheral edge of pipe P: Pipe Dci: Tip inner diameter of retaining ring Dco: Outer diameter of retaining ring Dpo: Outer diameter of pipe Dpi: Inner diameter of pipe Co: Chamfer dimension Ci: Chamfer dimension

Claims (4)

An outer cylinder (15) into which the tube (P) is inserted on the tip end side in the axial direction;
A retaining ring (42) provided on the inner peripheral surface of the outer cylindrical body (15) and engaged with the outer peripheral surface of the pipe (P) inserted into the outer cylindrical body (15),
The inner diameter (Dci) of the axial tip of the holding ring (42) is smaller than the outer diameter (Dpo) of the pipe (P), and the outer peripheral edge of the pipe (P) is chamfered (60). The pipe joint is formed larger than the outer diameter of the edge in the case.   The dimensional difference between the inner diameter (Dci) of the axial end of the retaining ring (42) and the outer diameter (Dpo) of the pipe (P) is 2.0% to 20% of the outer diameter (Dpo) of the pipe (P). The pipe joint according to claim 1, which is set within a range of 0.0%. An inner cylinder (14) into which the tip end in the axial direction is inserted into the pipe (P);
A retaining ring (42) that is provided on the outer peripheral surface of the inner cylindrical body (14) and engages with the inner peripheral surface of the pipe (P) into which the inner cylindrical body (14) is inserted,
The outer diameter (Dco) of the axial tip of the holding ring (42) is larger than the inner diameter (Dpi) of the pipe (P), and the inner peripheral edge of the pipe (P) is chamfered (62). A pipe joint characterized in that it is formed smaller than the inner diameter of the end edge in the case of.   The dimensional difference between the outer diameter (Dco) of the axial tip of the retaining ring (42) and the inner diameter (Dpi) of the pipe (P) is 2.0% to 20.0% of the inner diameter of the pipe (P). The pipe joint according to claim 3, which is set within a range.

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