Pressure-proof pipe joint

Abstract

To provide a pressure-proof pipe joint which does not need to use fire and a special tool when a connected pipe body is connected and enables improvement of a force for preventing drawing of the connected pipe body in a more advantageous manner while achieving excellent pressure resistance.SOLUTION: A pipe joint 10 includes: a joint body 12 having an insertion hole 24 into which a copper pipe 22 is inserted and fixed; a restriction ring 14 including an engagement claw 14b which prevents drawing of the copper pipe 22; a screw collar member 16 which may fix the restriction ring 14 to the inside of the insertion hole 24; an O ring 18 which seals a space between the copper pipe 22 and the insertion hole 24; and a pressurizing bush 20 which may pressurize and compress the O ring 18. The screw collar member 16 has an annular protruding part 34 which protrudes so as to enter an area below the bent engagement claw 14b of the restriction ring 14 at an inner peripheral edge part of a restriction ring 14 side end. The protruding part 34 is formed as a tapered surface having an inclined angle which is equal to or lower than an inclined angle of the engagement claw 14b.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a pressure-resistant pipe joint, and more particularly to a pressure-resistant pipe joint structure that can be suitably used for connecting pipes through which a fluid flows under high pressure, such as refrigerant pipes in air conditioning equipment. [Background technology]

[0002] Conventionally, various pipe fittings such as sockets, adapters, T-shaped, T-shaped, Y-shaped, cross-shaped, 90° elbows, etc. have been widely used to connect pipes that transport fluids such as liquids and gases to other pipes or to the desired equipment. For example, such pipe fittings have been used in connection work for water pipes, pipes for connecting hot water equipment, and refrigerant pipes in air conditioning equipment.

[0003] In the case of this type of pipe fitting, it has been common to use a brazing method to fasten the fitting to the pipe to be connected (connected pipe). However, because this requires the use of open flame during the work, it is difficult to employ this method for pipe connection work at piping sites such as above the ceiling. Therefore, various pipe fitting structures have been proposed that mechanically connect the connected pipe and the fitting without using open flame as in the conventional brazing method.

[0004] For example, in JP 2000-249268 A, as a joint structure that can be connected simply by inserting a connected pipe, when connecting a pipe and a joint body, a female thread formed on a pressing body is screwed into a male thread formed on the joint body, a lock ring or the like is sandwiched and fixed between the joint body and the pressing body, and a joint is proposed in which the pipe to be connected is inserted into the joint body through the pressing body, and the regulating piece of the lock ring is engaged with the outer peripheral surface of the pipe to prevent the pipe from being pulled out. In addition, JP 2019-90503 A also discloses a pipe joint structure in which a cap member is screwed into the opening of the joint body, and in a state in which a lock ring is sandwiched and fixed between the joint body and the cap member, the pipe to be connected is inserted into the joint body through the cap member, and the claws of the lock ring are allowed to bite into the outer peripheral surface of the pipe to restrict the insertion of the inserted pipe.

[0005] However, in these conventional pipe fitting structures in which a connected pipe is inserted, in order to prevent leakage of the fluid flowing through the connected pipe, it is necessary to provide sealing means in at least two locations, including a seal between the fitting body and the pressing body or the cap member, and a seal between the connected pipe and the pressing body or the cap member.As a result, not only does the sealing structure in the pipe fitting structure become complex, but there is also an inherent risk that the screwing of the pressing body or the cap member onto the fitting body will loosen, causing leakage or causing the connected pipe to fall off.

[0006] In addition, JP 2003-42369 A discloses a one-touch joint in which an O-ring and a restricting ring are inserted and arranged in order in one opening of a cylindrical joint body, and a ring-shaped retaining member is further inserted, and the end of the opening of the joint body is crimped inward to crimp and fix the retaining member, and by inserting a pipe to be connected into the opening of the joint body, the tip of the restricting tongue of the restricting ring bites into the outer circumferential surface of the pipe, preventing the pipe from being pulled out. However, since an O-ring sealing mechanism is disposed downstream in the pipe insertion direction, scratches are generated on the outer surface of the pipe that passes through the restricting ring when the pipe is inserted, and the O-ring seals the surface where the scratches occurred, so there is an inherent problem that the sealing characteristics cannot be fully exhibited.

[0007] Moreover, in the above-mentioned conventional insertion-type coupling structures, the connection pipe is attached by simply inserting it into the insertion hole of the coupling body, and the resistance to the connection pipe being pulled out is realized by the restricting piece or restricting tongue of the lock ring or restricting ring biting into the outer circumferential surface of the connection pipe, so there is an inherent problem that it is difficult to fully exert the pressure resistance and pull-out prevention force required for connection in piping through which a fluid flows under high pressure, such as refrigerant piping in an air conditioner. If the lock ring or restricting ring is provided in multiple stages or the restricting piece or restricting tongue of the lock ring or restricting ring is made hard or strong in order to increase the pull-out prevention force of such a connection pipe, the insertion resistance of the connection pipe becomes excessive, resulting in a problem that it becomes difficult for an operator to insert it manually.

[0008] Furthermore, JP 2022-29434 A discloses a pressure-resistant pipe joint that allows connection work to be performed using the normal force of an operator, even when the connected pipe has a large outer diameter. The joint body has a threaded collar member that is screwed into a threaded portion provided on the inner surface of the insertion hole of the joint body into which the connected pipe is inserted. A restricting ring is fixed in position within the insertion hole, and a plurality of locking claws of the restricting ring are spread radially outward to position a predetermined guide cylinder within the restricting ring. When the desired connected pipe is inserted, the end of the connected pipe is pressed against the guide cylinder to push it into the back of the insertion hole. In place of the guide cylinder, the connected pipe is inserted and positioned within the restricting ring, and the multiple locking claws are caused to dig into the outer surface of the connected pipe, thereby fixing and holding the connected pipe.

[0009] However, in these conventional joint structures, the lock ring or the restricting ring that prevents the connected pipe from being pulled out is fixed and held in the insertion hole of the joint body by an appropriate fixing member such as a thread collar member, and the restricting piece, the restricting tongue, or the engaging claw of the lock ring or the restricting ring is bent and inclined forward in the insertion direction of the connected pipe so as to bite into the outer surface of the connected pipe, so that when a large pulling force is applied to the connected pipe, the restricting piece, the restricting tongue, or the engaging claw may bend in the pulling direction due to the force, and the connected pipe may become detached. In particular, the larger the outer diameter of the connected pipe, the greater the pulling-out prevention force must be, but the conventional arrangement structure of the lock ring or the restricting ring cannot sufficiently meet this requirement. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2000-249268 A [Patent Document 2] JP 2019-90503 A [Patent Document 3] JP 2003-42369 A [Patent Document 4] Patent Publication No. 2022-29434 Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention has been made against the background of the above circumstances, and its problem to be solved is to provide a pressure-resistant pipe fitting which can connect a connected pipe without the use of fire or special tools, while ensuring excellent pressure resistance and more advantageously increasing the pull-out prevention force of the connected pipe. Another problem to be solved is to provide a pressure-resistant pipe fitting which can effectively connect connected pipes of various diameters, from small to large. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems or problems understood from the description of the entire specification and the drawings, the present invention can be preferably implemented in various aspects as listed below, and each aspect described below can be adopted in any combination. It should be understood that the aspects and technical features of the present invention are not limited to those described below, but can be recognized based on the technical contents disclosed in the description of the entire specification and the drawings.

[0013] Therefore, in order to solve the above-mentioned problems, the present invention provides a cylindrical coupling body having an insertion hole at least on one end side, into which a connected pipe is inserted from its pipe end and fixed; a restriction ring disposed in a fixed position within the insertion hole, the restriction ring having a plurality of elastically deformable locking claws positioned at predetermined intervals in the circumferential direction of the insertion hole, the locking claws biting into the outer surface of the connected pipe inserted into the insertion hole to prevent the connected pipe from being pulled out; and a restriction ring screwed into a threaded portion provided on the inner surface of the insertion hole to lock the restriction ring. a thick-walled cylindrical thread collar member that fixes the O-ring in the insertion hole; a sealing means consisting of an O-ring that is located axially outboard of the insertion hole relative to the thread collar member and disposed so as to be exposed in the insertion hole, and that contacts the outer surface of the connected pipe inserted into the insertion hole to seal between the outer surface of the connected pipe and the inner surface of the insertion hole; and a sealing means that is screwed onto the end of the coupling body on the side where the connected pipe is inserted, and as the screwing progresses, the O-ring is pressurized and compressed in the axial direction of the insertion hole, thereby sealing the O-ring. and a cylindrical pressure bushing having an insertion hole for a connected pipe to be inserted into the insertion hole formed in the axial direction, the insertion hole extending inwardly in the radial direction of the ring to enhance the pressing ability against the outer surface of the connected pipe, the regulating ring having a ring body having a predetermined width and a ring plate shape that is held in a fixed position within the insertion hole of the joint body, the plurality of locking claws being disposed so as to extend integrally from an inner periphery of the ring body toward the center of the ring body, and the plurality of locking claws being bent at their bases. The gist of the pressure-resistant pipe joint is that the thread collar member is inclined forward in the insertion direction of the connected pipe so as to form a predetermined inclination angle with respect to the axis perpendicular to the joint body, and the thread collar member has, integrally with the inner peripheral edge of the end portion on the regulating ring side, an annular protrusion that protrudes so as to fit under the bent locking claw of the regulating ring, and the annular protrusion has a tapered surface that is inclined at an inclination angle less than the inclination angle of the bent locking claw of the regulating ring.

[0014] According to one preferred aspect of the pressure-resistant pipe fitting of the present invention, the restricting ring is clamped and fixed by the thread collar member which is screwed into a threaded portion provided on the inner surface of the insertion hole, and abuts against a stepped portion formed on the inner surface of the insertion hole.

[0015] According to another preferable aspect of the pressure-resistant pipe fitting of the present invention, the difference between the inclination angle of the bent locking claws in the regulating ring and the inclination angle of the tapered surface in the annular protrusion of the thread collar member is 0° to 10°.

[0016] Furthermore, according to another preferred embodiment of the pressure resistant pipe joint of the present invention, the inclination angle of the tapered surface of the annular projection of the thread collar member is 20° or more.

[0017] In addition, the present invention is advantageously characterized in that the inclination angle of the bent locking claws of the regulating ring is 30° to 40°.

[0018] According to another desirable aspect of the pressure-resistant pipe fitting of the present invention, the annular protrusion of the thread collar member is provided in a form that presents a triangular cross-sectional shape by a cylindrical inner surface extending linearly outward from the inner circumferential surface of the thread collar member and the tapered surface.

[0019] Furthermore, according to yet another preferable aspect of the pressure-resistant pipe fitting according to the present invention, the bent locking claws of the regulating ring are arranged so that their tips are positioned radially inward from the inner circumferential surface of the thread collar member.

[0020] Furthermore, according to a preferred embodiment of the pressure-resistant pipe fitting of the present invention, at least one of the plurality of locking claws has a narrow portion at its base which is narrower than the width of the tip portion which bites into the outer surface of the connected pipe.

[0021] The present invention is advantageously characterized in that the pressure bush is attached by being screwed into a threaded portion provided on the inner peripheral portion of the end portion of the joint body on the insertion side of the connected pipe.

[0022] Furthermore, the present invention is advantageously characterized in that the pressure bush has a knurled outer surface, and by gripping the knurled portion, the worker can manually screw in the pressure bush.

[0023] Furthermore, the present invention is advantageously characterized in that a plurality of the O-rings are arranged in the axial direction of the insertion hole with annular spacers interposed between adjacent O-rings.

[0024] Furthermore, the present invention is advantageously characterized in that a stopper means is provided on the inner surface of the insertion hole deeper than the position of the regulating ring, against which the connected pipe body inserted into the insertion hole abuts, thereby preventing its movement.

[0025] In addition, the present invention is advantageously characterized in that the insertion holes are provided at both ends of the joint body, and the two connected pipes are connected by inserting and fixing the connected pipes into the insertion holes using the regulating ring, the thread collar member, the sealing means and the pressure bushing. Effect of the Invention

[0026] In a pressure-resistant pipe joint according to the present invention, the thread collar member for fixing the restraint ring, which is arranged in a fixed position within the insertion hole of the joint body, is made to protrude from the inner peripheral edge of the end portion on the restraint ring side so that the restraint ring fits under the locking claw which is bent and inclined forward in the insertion direction of the connected pipe, and is integrally formed with an annular protrusion having a tapered surface inclined at an angle less than the inclination angle of the bent locking claw on the restraint ring.Therefore, even if a large pulling-out force acts on the connected pipe and a force is applied to the locking claw in the opposite direction to the insertion direction of the connected pipe, the locking claw is received by the tapered surface of the annular protrusion provided on the thread collar member, and bending of the locking claw can be effectively prevented, so that the fixed state of the connected pipe can be advantageously maintained and the pull-out prevention action of the restraint ring can be effectively performed.

[0027] Furthermore, the force preventing the connected pipe from being pulled out, which is based on the locking claws on the regulating ring, is achieved by the tip of the locking claw biting into the outer surface of the connected pipe.Even if a large pulling force is applied, bending of the locking claws can be effectively prevented by the tapered surface of the annular protrusion provided on the thread collar member.As a result, the pull-out resistance force exerted by the tip of the locking claw biting into the outer surface of the connected pipe can be sufficiently secured. This not only makes it possible to exert sufficient pull-out resistance, but also because, by further screwing in the pressure bushing that is screwed onto the end of the joint body, the O-ring that seals between the inner surface of the insertion hole of the joint body and the outer surface of the connected pipe to be inserted is pressurized and compressed, causing it to bulge radially inwardly into the insertion hole, which effectively improves the adhesion or crimping ability to the outer peripheral surface of the inserted connected pipe, thereby achieving a joint structure with excellent pressure resistance.

[0028] In this way, with the pressure-resistant pipe fitting of the present invention, the connection between the connected pipe and the pipe fitting can be completed simply by inserting the desired connected pipe through the insertion hole in the pressure bush of the pipe fitting and then into the insertion hole of the fitting body, without the use of fire or any special dedicated tools. Since this pressure-resistant pipe fitting can exhibit excellent pressure resistance while also providing excellent pull-out prevention force, it can be advantageously used for connecting connected pipes through which a fluid such as a high-pressure refrigerant flows. It can also be advantageously used for connecting not only pipes with a small outer diameter, but also refrigerant pipes with a large outer diameter that are subjected to a large pull-out force due to the refrigerant pressure. [Brief description of the drawings]

[0029] [Figure 1] 1 is a partial longitudinal sectional view showing an example of a pressure-resistant pipe joint according to the present invention; [Diagram 2] 2 is an explanatory vertical sectional view showing the entire joint body used in the pressure-resistant pipe joint shown in FIG. 1. [Diagram 3] 2A and 2B are explanatory diagrams showing the state of a restricting ring used in the pressure-resistant pipe joint shown in FIG. 1 before the base of the locking claw is bent, where (a) is an explanatory plan view thereof, (b) is an explanatory right side view thereof, and (c) is an enlarged explanatory view of part A in (a). [Figure 4] 3 is an explanatory diagram showing a shape of a restricting ring used in the pressure-resistant pipe joint shown in FIG. 1 in which the locking claws are bent as shown in FIG. 3, (a) being its planar explanatory view, (b) being a cross-sectional view taken along line BB in (a), and (c) being an enlarged explanatory view of the cross section of the locking claws at part C in (b). [Diagram 5] 2A and 2B are explanatory diagrams showing a thread collar used in the pressure-resistant pipe fitting shown in FIG. 1, in which (a) is a front explanatory diagram, (b) is a DD cross-sectional explanatory diagram in (a), and (c) is an enlarged explanatory diagram of part E in (b). [Figure 6]2A and 2B are explanatory diagrams showing a pressure bushing used in the pressure-resistant pipe joint shown in FIG. 1, in which (a) is a front explanatory diagram, and (b) is an FF cross-sectional explanatory diagram in (a). [Figure 7] FIG. 2 is an explanatory longitudinal cross-sectional view showing the process of inserting and connecting a connected pipe body to the pressure-resistant pipe joint shown in FIG. 1, where (a) shows the state during the process of inserting the connected pipe body, and (b) shows the state after the connected pipe body has been inserted. [Figure 8] FIG. 2 is an explanatory diagram showing the shape of the connected pipe to be inserted and the locking claws of the regulating ring in the pressure-resistant pipe fitting shown in FIG. 1, where (a) is a cross-sectional explanatory diagram showing the shape before the connected pipe is inserted, and (b) is a cross-sectional explanatory diagram showing the shape after the connected pipe has been inserted. [Figure 9] 3A is a schematic explanatory diagram showing another form of a restraining ring used in the pressure-resistant pipe joint shown in FIG. 1, (a) being its plan view, (b) being a cross-sectional view taken along line GG in (a), and (c) being a partially enlarged explanatory view corresponding to FIG. 3C, showing the form of the locking claw before bending. [Figure 10] 2 is a longitudinal sectional view corresponding to FIG. 1 of a pressure-resistant pipe joint in which a pressure bush having a different structure is used. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] In order to clarify the configuration of the present invention more specifically, representative embodiments of the present invention will be described in detail below with reference to the drawings.

[0031] First, in Fig. 1, a representative example of a pressure-resistant pipe joint according to the present invention is shown in a longitudinal cross-sectional form, here in its left half. In this, the pipe joint 10 is configured to include a joint body 12 having an overall cylindrical shape, a restricting ring 14, a thread collar 16, and two O-rings 18, 18 each arranged in the joint body 12, and a pressure bush 20 screwed into an end opening of the joint body 12. The other half of the joint body 12 (the part on the right side not shown in Fig. 1) also has a structure similar to that of the left side part shown in the figure. And, a copper pipe 22 made of a material such as copper or a copper alloy is inserted as a connected pipe body into such a pipe joint 10 to be connected.

[0032] Specifically, the joint body 12, which is one of the components constituting the pipe joint 10, is made of a metal pipe of a predetermined length with a small diameter portion at the axial center, as shown in Fig. 2, and the pipes (copper pipes 22 in this case) to be connected are inserted from both ends of the joint body 12, respectively, and for this purpose, insertion holes 24, 24 for the pipes (copper pipes 22) are provided, which open at both ends. A ring-shaped protrusion 26 as a stopper means is integrally formed on the inner circumferential surface of the joint body 12 between the insertion holes 24, 24, protruding from the inner circumferential surface at a predetermined height so as to be located at the axial center of the joint body 12. The protrusion 26 is intended to prevent the movement of the copper pipe 22 by contacting the tip of the inserted copper pipe 22, as described later.

[0033] The insertion hole 24 of the joint body 12 is opened in a stepped form in which the diameter gradually increases toward the end of the joint body 12. An inlet side female thread 28 into which the pressure bush 20 is screwed is provided on the inner peripheral surface of the end opening where the inner diameter of the insertion hole 24 is the largest, and an inner female thread 30 into which the thread collar 16 is screwed is provided at an intermediate position between the opening and the protrusion 26. A tapered portion 24a consisting of an inclined surface that inclines toward the end opening of the joint body 12 and expands in diameter is provided between the insertion hole 24 located at the most central part in the axial direction and the innermost stepped part that provides the smallest inner diameter, so that the free elastic deformation of the restriction ring 14 in the radially outward direction is not hindered.

[0034] Further, the restriction ring 14 is formed in the form shown in Fig. 4(a)-(c) by bending the tongue-shaped locking claws 14b at their bases using the restriction ring precursor 14' shown in Fig. 3(a)-(c). Specifically, the restriction ring precursor 14' is configured to have a ring body 14a having a predetermined width and a plurality of (here, 16) plate-shaped locking claws 14b having a predetermined width, which extend integrally from the inner periphery of the ring body 14a toward the center of the ring body and are radially arranged at predetermined intervals in the circumferential direction. The restriction ring precursor 14' in this form can be easily manufactured, for example, by punching an elastic metal plate having a predetermined thickness with a press. Generally, the width of the locking claws 14b of the regulating ring 14 is about 1.6 to 3.0 mm, and the thickness of the locking claws 14b is about 0.5 to 1.0 mm.

[0035] The restricting ring precursor 14' has a plurality of locking claws 14b that are bent forward at their bases in the insertion direction of the copper pipe 22, which is the connected pipe body, and are bent at a predetermined angle α 14 is formed by inclining the restricting ring 14 at an angle of, for example, about 30° to 40°. The inner diameter of the restricting ring 14 formed at the tips of the bent locking claws 14b of the restricting ring 14 is designed to be smaller than the outer diameter of the copper tube 22 by about 1 to 2 mm. As a result, the restricting ring is made of a hard metal material having elasticity, for example, a metal material that can exhibit elastic properties such as SUS301, so that the locking claws 14b can bite into, or in other words, catch, the outer surface of the copper tube 22 in response to the pull-out behavior of the copper tube 22 connected by the pipe joint 10, and thus the locking claws 14b are elastically deformable. In addition, by making the restricting ring 14 out of a metal material such as SUS301, it is possible to advantageously maintain the necessary pull-out prevention force for a long period of time.

[0036] 1, the restriction ring 14 is disposed in a fixed position in such a manner that it abuts against the stepped portion at the innermost part of the insertion hole 24 in the joint body 12. As a result, when the copper tube 22, which is the connected pipe body, is inserted into the insertion hole 24 of the fitting body 12, the locking claws 14b of the regulating ring 14 are elastically pushed outward in the radial direction by the insertion force of the copper tube 22. At that time, the base of the locking claws 14b is bent toward the front side in the insertion direction of the copper tube 22, effectively reducing the bending deformation resistance of that portion, so that it is possible to insert the copper tube 22 into the regulating ring 14 without applying a large pushing force to the copper tube 22. On the other hand, after the copper tube 22 is inserted, the tip of the locking claws 14b is made into a pin angle at the corner on the side that contacts the copper tube 22, so that it bites into or gets caught on the outer surface of the copper tube 22, and therefore, even if a pulling force is applied to the copper tube 22, it is effectively prevented from slipping out.

[0037] 5(a)-(c), the thread collar 16 is made of a thick-walled cylindrical metal tube, and on its outer circumferential surface, a male threaded portion 16a and a stepped portion are formed in parallel in the axial direction. Four tool holes 16b are formed with a phase difference of 90° so as to open on the end surface on the side on which the male threaded portion 16a is formed. Furthermore, the inner part of the end opposite to the side on which the tool holes 16b are formed is configured as an annular protruding portion 34 protruding outward in the axial direction, and the outer circumferential portion of this protruding portion 34 is formed as a tapered portion (34a) that extends at an angle toward the center.

[0038] The thread collar 16 is turned with a tool using the tool hole 16b, so that the male thread portion 16a on its outer periphery is screwed into the internal female thread portion 30 on the inner surface of the insertion hole 24 of the joint body 12, thereby clamping and fixing the ring body 14a of the restriction ring 14 between the stepped portion provided at the innermost part of the insertion hole 24 of the joint body 12, as shown in Fig. 1. The stepped portion on the outer periphery of the thread collar 16 abuts against the stepped portion on the inner periphery of the insertion hole 24 of the joint body 12, so that further screwing can be prevented in a state in which the restriction ring 14 is fixed and held with a predetermined tightening force, and the inner hole 16c has an inner diameter large enough to allow the copper pipe 22 to be inserted therethrough.

[0039] The protrusion 34, which is an annular protrusion provided on the inner peripheral portion of the end face of the thread collar 16 on the side where the restricting ring 14 is disposed, protrudes outward in the axial direction, and its tapered inclined surface, in other words, tapered surface 34a, suppresses or prevents large deformation of the locking claws 14b when a pull-out force acts on the copper tube 22, thereby advantageously increasing the pull-out prevention force of the copper tube 22. Specifically, the protrusion 34 here has a cylindrical inner surface 34b that extends linearly outward in the axial direction from the inner peripheral surface of the thread collar 16 and a predetermined angle: α 2 4 and a tapered surface 34a that is inclined at the axial direction, so that the cross section of the groove 34 is in the shape of a right triangle.

[0040] The inclination angle of the tapered surface 34a of the protrusion 34 in such a screw collar 16 is: α 2 is the inclination angle of the bent locking claw 14b of the regulating ring 14: α 1 As a result, the deformation of the locking claws 14b when a pull-out force acts on the copper tube 22 can be effectively received by the tapered surface 34a of the protruding portion 34, thereby effectively preventing bending of the locking claws 14b and advantageously maintaining the fixed state of the locking claws 14b with respect to the copper tube 22, so that the pull-out prevention force can effectively work. 2 The inclination angle of the locking claw 14b is α 1 If the screw collar 16 is larger than this, when the regulating ring 14 is positioned and fixed in the insertion hole 24 of the joint body 12, the screw collar 16 will press down on the locking claw 14b before pressing down on the ring body 14a of the regulating ring 14, causing the screw collar 16 to float and raising the concern that the assembly will be completed in a loose screw state. There is a risk that the screw collar 16 will loosen due to vibration later on, causing problems such as the copper tube 22 slipping out together with the regulating ring 14.

[0041] In order to effectively utilize the pull-out prevention force based on the presence of the protrusion 34 having the tapered surface 34a in the screw collar 16, the inclination angle of the tapered surface 34a is set to α 2 is appropriately selected, but generally, an angle of 20° or more is advantageously selected. In order to effectively exert the pulling-out preventing force of the locking claws 14b of the restriction ring 14 on the copper tube 22 and to effectively maintain the fixed state of the restriction ring 14 by the thread collar 16, the inclination angle α of the bent locking claws 14b of the restriction ring 14 is set to α=1. 1 and the inclination angle of the tapered surface 34a of the annular protrusion 34 of the screw collar 16: α 2 Difference from (α 1 -α 2 It is desirable to set the difference between the inclination angles (α 1 -α 2) exceeds 10°, the gap between the protrusion 34 (tapered surface 34a) of the screw collar 16 and the bent locking claw 14b of the regulating ring 14 becomes large, and when a pulling force is applied, the protrusion 34 provided on the screw collar 16 cannot fully prevent the locking claw 14b from deforming. As a result, the locking claw 14b is significantly deformed, and problems such as it becoming easily bent may occur.

[0042] In this way, the threaded collar 16 fixes the regulating ring 14 and advantageously suppresses or prevents problems such as the locking claws 14b being significantly deformed or even bent due to the pulling force of the copper tube 22. It also contributes to the fixation of the O-ring 18 described below, and functions as a guide for the connected copper tube 22. It also has a vibration-damping effect that reduces the transmission of vibrations of the copper tube 22 to the regulating ring 14 and the O-ring 18 when the copper tube 22 vibrates.

[0043] The O-ring 18 is an annular body having a circular cross section made of a rubber material such as IIR or H-NBR, and as shown in Fig. 1, two O-rings 18, 18 having the same wire diameter and inner diameter are arranged with a circular plate-shaped spacer 36 sandwiched between them, and are arranged so that they are positioned axially outside the restriction ring 14 and the threaded collar 16 of the insertion hole 24 and exposed to the inner surface of the insertion hole 24 by being pressed by a pressure bushing 20 screwed onto the inner peripheral portion of the end of the joint body 12. The inner diameter of the two O-rings 18, 18 is made smaller than the outer diameter of the copper tube 22 so that a seal between the O-rings and the outer peripheral surface of the inserted copper tube 22 can be effectively achieved.

[0044] 6(a) and 6(b), the pressure bushing 20 is made of the same metal material as the joint body 12, has a thick-walled cylindrical shape, and has an insertion hole 20a large enough to insert a copper tube 22 as an inner hole. The pressure bushing 20 has a knurled portion 20b on the outer circumferential surface of the cylindrical wall thereof, which is knurled to be held by the operator's hand, and a male screw portion 20c that is screwed into the inlet female screw portion 28 of the joint body 12, with a circumferential groove of a predetermined depth therebetween. A ring-shaped hollow portion 20d is formed to a predetermined depth so as to open on the end face of the pressure bushing 20 on the side where the knurled portion 20b is provided, thereby reducing the weight of the pressure bushing 20. The pressure bushing 20 is screwed at its male thread portion 20c into the inlet female thread portion 28 of the fitting body 12, so that the pressure bushing 20 can be attached in a form having an outer shape that is smaller than the outer shape of the fitting body 12, as shown in FIG. 1, thereby making it possible to realize a compact pipe fitting 10 as a whole.

[0045] 1, the male threaded portion 20c of the pressure bushing 20 is screwed into the inlet side female threaded portion 28 of the joint body 12, and the pressure bushing 20 is attached to the end of the joint body 12, so that the two O-rings 18, 18 arranged via a spacer 36 are pressed by the screw-in end face of the pressure bushing 20, and the O-rings 18, 18 are accommodated and held in the end of the joint body 12 in a state in which they are sandwiched between the thread collar 16 and the spacer 36. In this state, the two O-rings 18, 18 are not compressed and deformed, so that no large insertion resistance occurs when the copper tube 22 is inserted.

[0046] When an operator holds a copper tube 22, which is a pipe to be connected, with his bare hands and inserts and connects it to the pipe fitting 10 assembled in the form shown in Fig. 1, the copper tube 22 is advanced further from the position shown in Fig. 1 and further from the position shown in Fig. 7(a) to be inserted into the pipe fitting 10, and the copper tube 22 is inserted further deeper after passing through the O-rings 18, 18 and the threaded collar 16 from the insertion hole 20a of the pressure bush 20. As a result, the copper tube 22 is pushed into the restriction ring 14, but the locking claws 14b of the restriction ring 14 are bent at their bases and inclined forward in the insertion direction so that they can be easily pushed outward in the radial direction, and therefore the copper tube 22 can be easily pushed into the restriction ring 14.

[0047] As the copper tube 22 advances further, the tip of the copper tube 22 comes into contact with the protrusions 26 provided on the inner surface of the fitting body 12, thereby restricting the insertion length of the copper tube 22. Meanwhile, the locking claws 14b of the restricting ring 14 elastically come into contact with the outer surface of the copper tube 22, and the locking claws 14b bite into the outer surface of the copper tube 22 at the pin-angled corners at their tip. As a result, even if a pull-out force is applied to the copper tube 22, a large pull-out resistance can be exerted, and thus an excellent pull-out prevention force for the copper tube 22 is achieved. Specifically, when the copper tube 22 is inserted deeper from the state shown in Fig. 8(a), the multiple locking claws 14b of the regulating ring 14 are spread apart, in other words, the copper tube 22 is inserted in a state in which the locking claws 14b are elastically curved and deformed forward in the insertion direction of the copper tube 22 and pushed apart, as shown in Fig. 8(b), and the corners of the locking claws 14b on the copper tube 22 side are thereby dug into the outer surface of the copper tube 22. Note that when the copper tube 22 is inserted in this state, the inclination angle (α 1The angle θ of the locking claw 14b is generally designed to be about 45° (±3°), which allows an effective pull-out resistance to be exerted, and the protrusion 34 protruding from the end of the threaded collar 16 on the regulating ring 14 side fits under the locking claw 14b, preventing large deformation of the locking claw 14b when a large pull-out force is applied to the copper tube 22, and preventing bending of the locking claw 14b, thereby advantageously improving the pull-out resistance.

[0048] Thereafter, as described above, in a state in which the copper tube 22 abuts against the ring-shaped ridge 26 on the inner surface of the joint body 12 and is prevented from moving further, the pressure bushing 20 is rotated by hand by an operator using the knurled portion 20b for rotation provided on its outer periphery, and the screwing progresses further, whereby the two O-rings 18, 18 are pressurized and compressed in the axial direction of the insertion hole 24 by the pressing force exerted by the abutment of the end faces of the pressure bushing 20. This causes the O-rings 18, 18 to bulge radially inward, increasing the pressing force against the outer periphery of the copper tube 22. As a result of the pressure and compression action caused by further screwing in of the pressure bushing 20, the O-rings 18, 18 take on a roughly rectangular cross-sectional shape as shown in Figure 7(b).As a result, the O-rings 18, 18 are strongly pressed against the outer circumferential surface of the copper tube 22 while increasing the pressure contact area, thereby further improving the seal between the outer circumferential surface of the copper tube 22 and the inner surface of the insertion hole 24.

[0049] The compression ratio of the O-ring 18 is generally recognized as being most effective in terms of pressure resistance and durability, and is set to approximately 25%±5%. The O-rings 18, 18 are pressed against the end face of the pressure bushing 20 so that such a compression ratio is achieved, in other words, so that the final compression ratio (%) is realized.

[0050] Therefore, in the case of the pipe fitting 10 having such a configuration, when connecting the copper pipe 22, which is the pipe to be connected, the worker can easily and simply grasp the copper pipe 22 with his bare hands and insert the end of the pipe through the insertion hole 20a of the pressure bushing 20 and into the insertion hole 24 of the fitting body 12 to complete the connection. Furthermore, even if a pulling force acts on the copper pipe 22 connected by such a pipe fitting 10, the deformation of the locking claws 14b of the restricting ring 14 due to the pulling force will not occur. The pull-out prevention force realized by the restraining ring 14 can be further increased by effectively preventing pull-out by the protrusion 34 (tapered surface 34a) provided on the collar 16, which not only eliminates the need to use fire, as in the conventional brazing method, but also completely eliminates the need to use special tools for the crimping work, as in the conventional crimping method. Therefore, all of the various problems caused by the use of fire and special tools can be completely eliminated.

[0051] Also, when the outer diameter of the copper tube 22 to be inserted is increased, it is necessary to increase the pull-out prevention force, but even in such a case, the structure of the illustrated pipe fitting 10 can advantageously deal with it. In short, the larger the diameter of the copper tube 22 to be connected, the greater the pull-out force of the copper tube 22. In order to increase the pull-out resistance of the copper tube 22, the thread collar 16 is provided with an annular protrusion 34 having a tapered surface 34a at the end on the regulating ring 14 side, and the protrusion 34 is designed to enter under the locking claws 14b. The presence of the protrusion 34 advantageously suppresses or prevents the deformation of the multiple locking claws 14b of the regulating ring 14 in the opposite direction to the insertion direction of the copper tube 22. As a result, even if the outer diameter of the inserted copper tube 22 is large, the pull-out prevention force can be effectively improved.

[0052] In addition, in the pipe joint having the above-mentioned configuration, the restriction ring 14 having the locking claws as shown in Figures 9(a) to (c) is advantageously used. That is, in the pipe joint, the base of each of the locking claws 14b (here, 12 claws) is configured as a narrow portion 38 having a width x narrower than the width y of the tip side.

[0053] In this way, by forming the locking claws 14b of the regulating ring 14 as narrow portions 38 at their bases, it is possible to advantageously reduce the reaction force due to the elastic deformation of the locking claws 14b. The width x of the narrow portions 38 is appropriately selected depending on the deformation resistance of the locking claws 14b. However, if the width is too narrow, problems such as buckling will occur. Therefore, in general, the ratio (x / y) of the width x of the narrow portions 38 at the bases of the locking claws 14b to the width y of the tips of the locking claws 14b is set to a value of about 0.2 to 0.9, preferably about 0.3 to 0.8. In order to satisfy such a ratio, the width x of the narrow portion 38 of the locking claw 14b is generally set to 0.6 to 1.6 mm, and the width y of the tip of the locking claw 14b is set to 1.6 to 3.0 mm. Furthermore, the thickness of the locking claw 14b is set to a value within the range of 0.5 to 1.0 mm, which is smaller than the width x of the narrow portion 38.

[0054] Moreover, the insertion operation of the copper tube 22 is performed by pushing the multiple locking claws 14b of the regulating ring 14 radially outward. Since the locking claws 14b have narrow portions 38 at their bases, which make it easy to push them radially outward, no large insertion force is required when inserting the copper tube 22 into the regulating ring 14. Therefore, the copper tube 22 can be easily inserted by hand by the worker. In addition, since there is no need to use components such as an induction cylinder, this also contributes to a reduction in the number of parts.

[0055] Although typical embodiments of the present invention have been described above in detail, it should be understood that these are merely examples, and that the present invention should not be construed in any way as being limited to the specific descriptions of such embodiments.

[0056] For example, in the above-described embodiment, a pipe fitting for linearly connecting two copper pipes 22 as the connected pipes has been described as an example, but the present invention is in no way limited to this, and can be advantageously applied to any of the various types of conventionally known pipe fittings with various names, such as sockets, adapters, tee, T-shaped, Y-shaped, cross-shaped, 90° elbows, etc., which are used to connect a pipe for transporting a fluid such as a liquid or gas to another pipe of a different diameter, or to connect to the target equipment.

[0057] In addition, in the present invention, instead of the pressure bush 20 having the structure as illustrated, a pressure bush 40 having a thin wall as shown in Fig. 10 can be advantageously used. In order to further reduce the weight and the outer diameter of the bush, this pressure bush 40 has a configuration in which the cylindrical wall portion located radially outside the hollowed-out portion 20d in the previous pressure bush 20 is removed, and the outer surface of the cylindrical wall portion located radially inside the hollowed-out portion 20d is knurled to form a knurled portion 40b, so that an operator can hold the knurled portion 40b and rotate the pressure bush 20 with bare hands. Note that, like the previous pressure bush 20, the pressure bush 40 has an insertion hole 40a, and a male screw portion 40c that screws into the inlet female screw portion 28 provided on the inner peripheral portion of the end of the joint body 12 is provided on the outer peripheral surface.

[0058] Furthermore, in the illustrated embodiment, 16 or 12 locking claws 14b are provided integrally with the restriction ring 14 at predetermined intervals in the circumferential direction, but the number is appropriately selected taking into consideration the insertion resistance and pull-out prevention force of the copper tube 22, and is generally provided at equal intervals in a ratio of 6 to 18. Of course, the locking claws 14b can be provided at any interval other than equal intervals.

[0059] 9, all of the locking claws 14b have a base portion that is a narrow portion 38, but the number of locking claws 14b provided with such narrow portions 38 is appropriately selected according to the desired insertion resistance, and as the number of locking claws 14b provided with such narrow portions 38 increases, it is possible to reduce the insertion resistance of the copper tube 22. Also, as for the width of the narrow portions 38 provided at the base of the locking claws 14b, in addition to the example in which all the narrow portions 38 are provided with the same width, it is also possible to make the width of the narrow portions 38 different for each locking claw 14b.

[0060] Furthermore, the number of restriction rings 14 is appropriately selected so that effective pressure resistance and pull-out prevention force can be exhibited depending on the diameter of the copper pipe 22 to be connected and the pressure of the fluid flowing therethrough, and there is no problem with using multiple stages in addition to using one stage as in the illustrated embodiment. When using multiple restriction rings 14 and arranging them in multiple stages, they are arranged in the insertion hole 24 of the joint body 12 in a form in which a spacer of a predetermined thickness is interposed between each ring body 14a to avoid mutual interference of the locking claws 14b. However, such a spacer is not necessarily required as long as an appropriate interval can be secured between adjacent restriction rings 14, 14. For example, it is possible to form a predetermined gap between them by increasing the thickness of the ring body 14a.

[0061] In the illustrated embodiment, two O-rings 18 having the same wire diameter and inner diameter are used as the O-rings 18, but it is also possible to use two O-rings 18 having the same inner diameter but different wire diameters (thickness). In this case, the O-ring with the smaller wire diameter is arranged so as to be located at the back side of the insertion hole 24, and a stepped portion with a different inner diameter is provided on the inner surface of the joint body 12, and the two O-rings 18 with different wire diameters are arranged thereon.

[0062] In addition, as for the method of manufacturing the regulating ring 14, in addition to the method of forming a regulating ring precursor 14' as shown in Figure 3, as illustrated, and then bending its locking claws 14b at its base to complete the regulating ring 14 in the form shown in Figure 4, various known methods can be adopted.For example, a method can be adopted in which the inner diameter shape of the ring body 14a and the locking claws 14b are punched out of a metal plate using a press, the locking claws 14b are then bent at their base, and the metal plate is then pressed to punch out the outer diameter shape of the ring body 14a, thereby obtaining the desired regulating ring 14.

[0063] Furthermore, the annular protrusion 34 protruding from the end of the screw collar 16 on the regulating ring 14 side can be provided in a protrusion form having an appropriate cross-sectional shape as long as it has a tapered surface 34a according to the present invention.In addition to being provided in a right-angled triangular cross-sectional shape as in the exemplary embodiment, it can also be provided as an annular protrusion having various cross-sectional shapes such as an isosceles triangle shape, a scalene triangle shape, a trapezoid shape, etc.

[0064] In addition, the connected pipe may be made of any metal material such as aluminum or its alloy, other than the copper pipe 22, and generally, a pipe made of a soft metal material is advantageously used. Furthermore, the material of the restricting ring 14 is not limited to SUS, and a metal material harder than the connected pipe is advantageously used.

[0065] In addition, although we will not list them one by one, the present invention can be implemented in various forms with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and it goes without saying that all such implementation forms fall within the scope of the present invention as long as they do not deviate from the spirit of the present invention. [Explanation of symbols]

[0066] 10 Pipe joint 12 Joint body 14 Regulating ring 14a Ring body 14b Locking claw 14' Restriction ring precursor 16 Thread collar 16a Male thread 16b Tool hole 16c Inner hole 18 O-ring 20 Pressure bush 20a Insertion hole 20b Knurled portion 20c Male thread 20d Hollowed out part 22 Copper tube 24 Insertion hole 24a Tapered portion 26 Ridge 28 Inlet side female thread 30 Inside female thread 34 Projection 38 Narrow width 40 Pressure bush 40a Insertion hole 40b Knurled portion 40c Male thread portion

Claims

1. a cylindrical coupling body having an insertion hole at least on one end side into which a connected pipe is inserted from its pipe end and fixed; a restriction ring disposed in a fixed position within the insertion hole and having a plurality of elastically deformable locking claws positioned at predetermined intervals in the circumferential direction of the insertion hole, the locking claws dig into the outer surface of the connected pipe inserted into the insertion hole to prevent the connected pipe from being pulled out; a thick-walled cylindrical thread collar member screwed into a threaded portion provided on the inner surface of the insertion hole to fix the restriction ring within the insertion hole; and a thread collar member positioned axially outboard of the insertion hole relative to the thread collar member and configured to lock the restriction ring within the insertion hole. a sealing means comprising an O-ring disposed so as to be exposed within an insertion hole and in contact with an outer surface of the connected pipe inserted into the insertion hole to seal between the outer surface of the connected pipe and the inner surface of the insertion hole; and a cylindrical pressure bushing having an insertion hole formed in the axial direction of the connected pipe inserted into the insertion hole, which is screwed onto an end of the joint body on the side where the connected pipe is inserted, and which, as the screwing progresses, pressurizes and compresses the O-ring in the axial direction of the insertion hole, causing the O-ring to bulge radially inwardly, thereby enhancing the pressing ability against the outer surface of the connected pipe, a first end of the threaded collar member facing the first pipe and a second end of the threaded collar member facing the first pipe, the first end of the threaded collar member facing the first pipe, and the second end of the threaded collar member facing the first pipe, the first end of the threaded collar member facing the first pipe, the second end of the threaded collar member facing the first pipe, the second end of the threaded collar member facing the first pipe, the second end of the threaded collar member facing the first pipe, the second end of the threaded collar member facing the first pipe, the second end of the threaded collar member facing the first pipe, the second end of the threaded collar member facing the first pipe,

2. 2. The pressure-resistant pipe joint according to claim 1, characterized in that the regulating ring is abutted against a stepped portion formed on the inner surface of the insertion hole by the thread collar member which is screwed into a threaded portion provided on the inner surface of the insertion hole, thereby clamping and fixing the regulating ring.

3. The pressure-resistant pipe joint according to claim 1, characterized in that the difference between the inclination angle of the bent locking claws in the regulating ring and the inclination angle of the tapered surface in the annular protrusion of the thread collar member is 0° to 10°.

4. 2. A pressure-resistant pipe joint according to claim 1, characterized in that the inclination angle of the tapered surface of the annular protrusion of the thread collar member is 20° or more.

5. 2. The pressure-resistant pipe joint according to claim 1, wherein the inclination angle of the bent locking claws of the regulating ring is 30° to 40°.

6. 2. A pressure-resistant pipe fitting as described in claim 1, wherein the annular protrusion of the thread collar member is provided in a form that presents a triangular cross-sectional shape by a cylindrical inner surface extending linearly outward from the inner circumferential surface of the thread collar member and the tapered surface.

7. 2. A pressure-resistant pipe joint according to claim 1, characterized in that the bent locking claws of the regulating ring are arranged so that their tips are located radially inward from the inner circumferential surface of the thread collar member.

8. A pressure-resistant pipe fitting as described in claim 1, characterized in that at least one of the multiple locking claws has a narrow portion at its base that is narrower than the width of the tip portion that bites into the outer surface of the connected pipe.

9. 2. A pressure-resistant pipe joint according to claim 1, characterized in that the pressure bush is attached by being screwed into a threaded portion provided on an inner peripheral portion of an end portion of the joint body on which the connected pipe is inserted.

10. 2. A pressure-resistant pipe joint as claimed in claim 1, characterized in that the pressure bushing has a knurled outer surface, and the pressure bushing can be screwed in by hand by gripping the knurled portion.

11. A pressure-resistant pipe joint as described in claim 1, characterized in that a plurality of the O-rings are arranged in the axial direction of the insertion hole with annular spacers interposed between adjacent O-rings.

12. 2. The pressure-resistant pipe joint according to claim 1, further comprising a stopper means provided on the inner surface of the insertion hole deeper than the position of the regulating ring, against which the connected pipe inserted into the insertion hole abuts to prevent its movement.

13. 13. A pressure-resistant pipe joint as claimed in any one of claims 1 to 12, characterized in that the insertion holes are provided at both ends of the joint body, and the two connected pipes are connected to each other by inserting and fixing the connected pipes into the insertion holes using the regulating ring, the thread collar member, the sealing means and the pressure bushing.

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