Pressure resistance pipe joint

Abstract

To provide a pressure-resistance pipe joint which does not use fire at the connection of a connected pipe body, does not need to use a dedicated tool, can maintain the insertion resistance of the connected pipe body low while securing excellent pressure resistance, and is suppressed in the number of components.SOLUTION: In a pipe joint 10 having: a joint main body 12 to which a copper pipe 22 is inserted and fixed; a regulation ring 14 including a plurality of lock claws 14b for preventing the withdrawal of the copper pipe 22; an O-ring 18 located axially outside an insertion hole 24 rather than the regulation ring 14 and sealing a clearance between the copper pipe 22 and the insertion hole 24; and a pressurization bush 20 screwed to the joint main body 12, and pressurizing and compressing the O-ring 18 by the progress of the screwing, a base part of the lock claw 14b is formed into a narrow width part 32 which becomes narrower in a width than a tip part which bites into an outer surface of the copper pipe 22, curved at the narrow width part 32, and inclined to an insertion direction front side of the copper pipe 22.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 fluids such as refrigerant pipes in air-conditioning equipment flow under high pressure.

Background Art

[0002] Conventionally, various pipe joints such as sockets, adapters, tees, T-shaped, Y-shaped, cross-shaped, 90° elbows, etc. have been widely used to connect pipes for transporting fluids such as liquids and gases to other pipes or to target devices. For example, connection work for water pipes, pipes for connecting hot water equipment, refrigerant pipes in air-conditioning equipment, etc. has been carried out using such pipe joints.

[0003] By the way, in this type of pipe joint, when connecting the pipe to be connected (the pipe to be joined) and the joint, it was common to adopt a brazing method of fixing them by brazing. However, since it is necessary to use fire during the operation, it is difficult to adopt it for pipe connection work at pipe sites such as in the ceiling space. Therefore, various pipe joint structures have been proposed that mechanically connect the two without using fire such as conventional brazing when connecting the pipe to be connected and the joint.

[0004] For example, as a joint structure that can be connected simply by inserting the pipe to be connected, in Japanese Patent Application Laid-Open No. 2000-249268, when connecting a pipe and a joint body, a female screw formed on a pressing body is screwed onto a male screw formed on the joint body, and a lock ring or the like is clamped and fixed between the joint body and the pressing body. Then, the pipe to be connected is inserted into the joint body through such a pressing body, and a regulating piece of the lock ring is engaged with the outer peripheral surface of the pipe to prevent the pipe from being pulled out. A joint has been proposed. Also, in Japanese Patent Application Laid-Open No. 2019-90503, while screwing a cap member onto the opening of the joint body and clamping and fixing a lock ring between the joint body and the cap member, the pipe body to be connected is inserted into the joint body through the cap member, and by causing the claw of the lock ring to bite into the outer peripheral surface thereof, a pipe joint structure has been disclosed that regulates the pulling out of such an inserted pipe body.

[0005] However, in the pipe joint structure of the type that inserts the pipes to be connected, in order to prevent leakage of the fluid flowing through the pipes to be connected, in addition to the seal between the joint body and the pressing body or the cap member, at least two seal means including the seal between the pipe to be connected and the pressing body or the cap member need to be provided. Therefore, not only does the seal structure in the pipe joint structure become complicated, but there is also an inherent risk that the screwing of the pressing body or the cap member to the joint body may become loose, resulting in leakage or the pipe to be connected falling off.

[0006] In addition, in Japanese Patent Application Laid-Open No. 2003-42369, as a one-touch joint, an O-ring and a restricting ring are sequentially inserted and arranged in one opening of a cylindrical joint body, and further, in a state where a ring-shaped holding member is inserted, by caulking the end portion of the opening of the joint body inward, a joint structure in a form in which the holding member is caulked and fixed is disclosed. By inserting a pipe to be connected into the opening of such a joint body, the tip of the restricting tongue of the restricting ring bites into the outer peripheral surface of this pipe, and the removal of such a pipe is prevented. However, there, since a sealing mechanism by an O-ring is arranged on the downstream side in the insertion direction of the pipe, scratches are generated on the outer surface of the pipe that has passed through the restricting ring by the insertion of the pipe, and sealing by the O-ring is performed on the surface where the scratches are generated. Therefore, there was an inherent problem that the sealing characteristics could not be sufficiently exhibited.

[0007] Moreover, in the conventional insertion-type joint structure as described above, the connected pipe can be attached simply by inserting it into the insertion hole of the joint body. The resistance to pulling out the connected pipe is achieved by the locking ring, the regulating piece or the regulating tongue of the regulating ring biting into the outer peripheral surface of the connected pipe. Therefore, in a pipe such as a refrigerant pipe in air conditioning equipment where fluid flows under high pressure, there is an inherent problem that it is difficult to fully exhibit the pressure resistance and the pulling-out prevention force required for its connection. Further, in order to increase the pulling-out prevention force of the connected pipe, if a plurality of locking rings or regulating rings are installed in multiple stages, or if the regulating pieces or regulating tongues of these locking rings or regulating rings are made highly rigid or high-strength, the insertion resistance of the connected pipe becomes excessive, and there arises a problem that it becomes difficult to insert by the manual work of the operator. In particular, the larger the pipe diameter of the connected pipe, the greater the insertion resistance of the connected pipe. Specifically, when the pipe diameter (outer diameter / call diameter) of the connected pipe is 22.22 mm or more, an insertion force is required such that it cannot be inserted with the strength of a standard average male. For example, in order to insert a connected pipe with a pipe diameter of 28.58 mm, an insertion force of 0.6 kN or more is required, so it was extremely difficult to insert the connected pipe by the bare hands of the operator.

[0008] Therefore, the applicant of the present application has proposed, in Japanese Patent Application Laid-Open No. 2022-29434, a pressure-resistant pipe joint that enables connection work to be performed using the normal force of an operator even for a pipe body to be connected with a large outer diameter of the pipe. A plurality of locking claws of a regulating ring fixedly arranged in an insertion hole of a joint body are expanded radially outward, and a predetermined guiding cylinder body is arranged in such a regulating ring. When the target pipe body to be connected is inserted, the guiding cylinder body is pressed at the end of the pipe body to be connected and pushed into the inner part of the insertion hole. Instead of such a guiding cylinder body, the pipe body to be connected is fitted into the regulating ring, and a plurality of locking claws are bitten into the outer surface of the pipe body to be connected to fix and hold the pipe body to be connected. As a result, the work of fitting and arranging the pipe body to be connected into the regulating ring can be performed relatively easily, simply, and quickly by the operator's hand.

[0009] However, in such a pressure-resistant pipe joint using a guiding cylinder body, it is necessary to prepare a special member called a guiding cylinder body. Therefore, the number of parts constituting the pipe joint increases, and accordingly, there is a problem that the cost increase based on this cannot be avoided. In addition, in the insertion hole of the joint body of the pipe joint, it is necessary to insert the guiding cylinder body in advance and arrange it so as to expand a plurality of locking claws of the regulating ring radially outward. Also in this regard, there is a problem that the number of working steps increases.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0011] Here, the present invention has been made against such a background, and the problem to be solved is that when connecting the connected pipe body, without using fire and without the need to use a dedicated tool, while ensuring excellent pressure resistance, it is possible to maintain a low insertion resistance of the connected pipe body and provide a pressure-resistant pipe joint with a small number of parts. Another problem is to provide a pressure-resistant pipe joint that enables connection work using the normal force of an operator even for a large-diameter connected pipe body with an outer pipe diameter of 19 mm or more.

Means for Solving the Problems

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

[0013] Therefore, in order to solve the above-described problems, the present invention first provides a cylindrical joint body having an insertion hole at at least one end portion side, into which a connected pipe body is inserted from its pipe end and fixed; a plurality of elastically deformable locking claws that bite into the outer surface of the connected pipe body inserted into the insertion hole and prevent the pulling out of the connected pipe body, and are provided at predetermined intervals in the circumferential direction of the insertion hole; a regulating ring fixedly disposed in the insertion hole; a sealing means comprising an O-ring that is disposed on the outer side in the axial direction of the insertion hole with respect to the regulating ring, is disposed so as to be exposed in the insertion hole, contacts the outer surface of the connected pipe body inserted into the insertion hole, and seals between the outer surface of the connected pipe body and the inner surface of the insertion hole; and a pressing bush having a cylindrical shape with an insertion hole for the connected pipe body formed in the axial direction, which is screwed to the end portion on the connected pipe body insertion side of the joint body, and by advancing such screwing, presses and compresses the O-ring in the axial direction of the insertion hole, thereby bulging the O-ring radially inward to enhance the pressure-bonding property to the outer surface of the connected pipe body. The regulating ring has an annular plate-shaped ring body with a predetermined width that is fixedly held in the insertion hole of the joint body, and the plurality of locking claws are disposed so as to integrally extend from the inner peripheral portion of the ring body toward the center of the ring body. At least one of the plurality of locking claws has a narrow-width portion that is narrower than the width of the tip portion that bites into the outer surface of the connected pipe body at its base, and is bent at the narrow-width portion and inclined toward the front side in the insertion direction of the connected pipe body. The gist of the present invention is a pressure-resistant pipe joint having the above features.

[0014] In accordance with one desirable aspect of the pressure-resistant pipe joint according to the present invention as described above, the regulating ring is screwed to a screw collar member that is screwed to a screw portion provided on the inner surface of the insertion hole, and is brought into contact with a stepped portion formed on the inner surface of the insertion hole so as to be clamped and fixed.

[0015] According to another preferred aspect of the pressure-resistant pipe joint according to the present invention, the pressure bush is screwed onto a screw portion provided on the inner peripheral portion of the end on the side where the pipe to be connected is inserted of the joint body, and is configured to be attached.

[0016] Furthermore, according to another preferred aspect of the pressure-resistant pipe joint according to the present invention, the pressure bush is knurled on its outer peripheral surface, and by gripping the knurled portion, the screwing operation of the pressure bush can be performed by the operator's hand.

[0017] In addition, in the present invention, advantageously, a plurality of the O-rings are arranged in the axial direction of the insertion hole in a form in which an annular spacer is interposed between adjacent O-rings.

[0018] Also, according to another preferred aspect of the pressure-resistant pipe joint according to the present invention, stopper means is provided on the inner surface of the insertion hole on the inner side from the arrangement position of the restricting ring, and the pipe to be connected inserted into the insertion hole is brought into contact therewith to prevent its movement.

[0019] Furthermore, according to still another preferred aspect of the pressure-resistant pipe joint according to the present invention, insertion holes are respectively provided at both ends of the joint body, and the pipes to be connected are inserted and fixed to these insertion holes using the restricting ring, the sealing means, and the pressure bush, respectively, so that two pipes to be connected are connected.

[0020] Furthermore, according to a preferred aspect of the pressure-resistant pipe joint according to the present invention, the pipe to be connected is a large-diameter pipe having an outer diameter of 19 mm or more.

Effects of the Invention

[0021] In such a pressure-resistant pipe joint according to the present invention, among the plurality of locking claws of the restricting ring disposed in the insertion hole of the joint body in a position-fixed manner, at least one base portion thereof is formed with a narrow-width portion having a narrower clamping width than the width of the tip portion, and is formed in a form that is bent at the narrow-width portion. Therefore, when a predetermined pipe to be connected is inserted, the locking claw having such a narrow-width portion is easily pushed and expanded radially outward. As a result, the insertion resistance of the pipe to be connected to the restricting ring can be effectively reduced. Thus, without using the guiding cylinder proposed by the applicant of the present application in advance, the operation of fitting and arranging the pipe to be connected into the restricting ring can be performed relatively easily, simply, and quickly by the operator's hand. Thus, it can be advantageously used as a so-called one-touch joint.

[0022] Moreover, the exertion of the pulling-out preventing force of the pipe to be connected based on the locking claw in the restricting ring is realized by the tip portion of such a locking claw biting into the outer surface of the pipe to be connected. Therefore, even if the base portion of the locking claw is a narrow-width portion, there is no change in the width of the tip portion. Accordingly, there is almost no change in the pulling-out resistance force developed by such a tip portion biting into the outer surface of the pipe to be connected. Therefore, in addition to being able to exert sufficient pulling-out resistance force, by further screwing in the pressure bush screwed to the end portion 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 inserted pipe to be connected is pressurized and compressed so as to bulge radially inward of the insertion hole. Therefore, the adhesion or crimping property to the outer peripheral surface of the inserted pipe to be connected can be effectively enhanced. As a result, a joint structure excellent in pressure resistance can be realized.

[0023] Thus, according to the pressure-resistant pipe joint according to the present invention, without using fire or special dedicated tools, and furthermore, without the need to expand the locking claws of the regulating ring with an induction cylinder body, under low insertion resistance, simply by the insertion operation of the operator's bare hands, the target pipe to be connected is inserted through the insertion hole provided in the pressure bush of the pipe joint, and then the operation of inserting it into the insertion hole of the joint body is carried out. Just by doing this, the connection between the pipes to be connected and the pipe joint is completed. While reducing the number of parts, and being able to exhibit excellent pressure resistance, it can be advantageously adopted for connecting pipes to be connected through which fluids such as high-pressure refrigerants flow inside the pipe. In addition, not only for pipes with a small outer diameter, but also for refrigerant pipes with a large outer diameter having an outer diameter of 19 mm or more and up to 38.1 mm, the feature that their connection can be advantageously carried out can be exhibited.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0025] Hereinafter, in order to more specifically clarify the configuration of the present invention, representative embodiments of the present invention will be described in detail with reference to the drawings.

[0026] First, in FIG. 1, a representative example of a pressure-resistant pipe joint according to the present invention is shown here in a longitudinal sectional form for the left half thereof. Therein, the pipe joint 10 includes a joint body 12 having a cylindrical shape as a whole, a restricting ring 14, a screw collar 16, and two O-rings 18, 18 respectively arranged in such a joint body 12, and a pressure bush 20 screwed to the end opening of the joint body 12. Note that the other half of the joint body 12 (the portion not shown on the right side in FIG. 1) has the same structure as the left side portion shown. And for such a pipe joint 10, a copper pipe 22 made of a material such as copper or a copper alloy, for example, is inserted as the pipe body to be connected and is to be connected.

[0027] Specifically, the joint body 12, which is one of the members constituting such a pipe joint 10, is made of a metal pipe body of a predetermined length with a small-diameter portion at the central part in the axial direction as shown in Fig. 2. From both ends thereof, the pipe bodies (here, copper pipes 22) to be connected are inserted and connected respectively. Therefore, insertion holes 24, 24 for the pipe bodies (copper pipes 22) are provided at both ends and open respectively. And between these insertion holes 24, 24, a ring-shaped protrusion 26 as a stopper means protruding from the inner peripheral surface at a predetermined height is integrally formed on the inner peripheral surface of the joint body 12 so as to be located at the central part in the axial direction of the joint body 12. Incidentally, as will be described later, this protrusion 26 is for preventing the movement of the copper pipe 22 by allowing the tip of the copper pipe 22 to be inserted to abut thereon.

[0028] Also, the insertion holes 24 of the joint body 12 are formed to open in a stepped form in which the diameter gradually expands toward the end of the joint body 12. An inlet-side female screw portion 28 into which the pressure bush 20 is screwed is provided on the inner peripheral surface of the end opening portion where the inner diameter of the insertion hole 24 is the largest. Further, an inner female screw portion 30 into which the screw collar 16 is screwed is provided at an intermediate position between the opening portion and the protrusion 26. Incidentally, between the insertion hole 24 portion located on the most central side in the axial direction and the innermost stepped portion having the smallest inner diameter, a tapered portion 24a composed of an inclined surface that is inclined toward the end opening portion of the joint body 12 and has an enlarged diameter is provided, so that the free elastic deformation of the regulating ring 14 outward in the radial direction is not inhibited.

[0029] Furthermore, the restricting ring 14 is formed here in the form shown in FIGS. 4(a) to (c) by using the restricting ring precursor 14' shown in FIGS. 3(a) to (c) and bending its tongue-shaped locking claws 14b at their bases. Therein, the restricting ring precursor 14' is specifically configured to have a ring body 14a in the shape of an annular plate with a predetermined width, and a plurality (here, 12) of plate-shaped locking pieces 14b with a predetermined width, which are integrally extended from the inner peripheral portion of the ring body 14a toward the center of the ring body and radially arranged at predetermined intervals in the circumferential direction. And here, the base of each locking piece 14b is configured as a narrow-width portion 32 having a narrow width: x that is narrower than the width: y on the tip side thereof. Note that the restricting ring precursor 14' in such a form can be easily manufactured, for example, by punching a predetermined metal plate having elasticity with a press.

[0030] Then, in the restricting ring precursor 14', its plurality of locking claws 14b are bent forward in the insertion direction of the copper pipe 22, which is the pipe to be connected, at the narrow-width portion 32 of their bases, and are inclined so as to form a predetermined angle: α, for example, an angle of about 30° to 40°, with respect to the plane perpendicular to the axis of the joint body 12, in other words, with respect to the plate surface of the ring body 14a. Thus, the restricting ring 14 shown in FIG. 4 is formed. Note that the inner diameter of the restricting ring 14 formed at the tips of the plurality of bent locking claws 14b in the restricting ring 14 is designed to be smaller than the outer diameter of the copper pipe 22. Thereby, with respect to the pulling-out behavior of the copper pipe 22 connected by the pipe joint 10, the locking claws 14b can bite into, in other words, can catch on, the outer surface of the copper pipe 22. The restricting ring is made of a hard metal material having elasticity, for example, a metal material capable of exhibiting elastic characteristics such as SUS301. Thus, the locking claws 14b are made to be elastically deformable. Also, by configuring the restricting ring 14 with a metal material such as SUS301, it is possible to advantageously maintain the necessary pulling-out preventing force over a long period.

[0031] And, as shown in FIG. 1, such a regulating ring 14 is disposed in a position-fixed manner in a form that abuts against a stepped portion at the innermost part of the insertion hole 24 in the joint body 12. Thus, when the copper pipe 22, which is the pipe to be connected, is inserted into the insertion hole 24 of the joint body 12, the locking claws 14b of the regulating ring 14 are elastically pushed and expanded radially outward by the insertion force of the copper pipe 22. At this time, since the base portion of the locking claw 14b is a narrow portion 32 and the bending deformation resistance of this portion is effectively reduced, it is possible to insert the copper pipe 22 into the regulating ring 14 without applying a large pushing force to the copper pipe 22. On the other hand, after the copper pipe 22 is inserted, since the tip of the locking claw 14b is formed as a pin angle at the corner on the side in contact with the copper pipe 22, it bites into or catches on the outer surface of the copper pipe 22. Therefore, even if a pulling force acts on the copper pipe 22, its slipping out can be effectively prevented.

[0032] Thus, by making the locking claw 14b of the regulating ring 14 into a narrow portion 32 at its base, it is possible to advantageously reduce the reaction force based on the elastic deformation of the locking claw 14b. The width x of the narrow portion 32 is appropriately selected according to the deformation resistance of the locking claw 14b. However, if it is too narrow, problems such as buckling will occur. Generally, the ratio (x / y) of the width x of the narrow portion 32 at the base of the locking claw 14b to the width y of the tip of the locking claw 14b is about 0.2 to 0.9, preferably about 0.3 to 0.8. And, generally, the width x of the narrow portion 32 of the locking claw 14b is 0.6 to 1.6 mm, and the width y of the tip of the locking claw 14b is 1.6 to 3.0 mm so as to satisfy such a ratio. Further, as the thickness of the locking claw 14b, a value smaller than the width x of the narrow portion 32 is adopted within the range of 0.5 to 1.0 mm.

[0033] Further, as is clear from FIGS. 5(a) and (b), the screw collar 16 is made of a thick-walled cylindrical metal cylinder, and on its outer peripheral surface, a male screw portion 16a and a stepped portion are formed in a form arranged in parallel in the axial direction. And four tool holes 16b are formed with a 90° phase difference so as to open to the end surface on the side where the male screw portion 16a is provided. Further, the inner part of the end on the side opposite to the side where the tool hole 16b is provided is configured as a protruding portion 34 protruding axially outward, and the outer peripheral portion of this protruding portion 34 is a tapered shape portion that extends inclined toward the center.

[0034] And, by rotating the screw collar 16 with a tool using the tool hole 16b, the male screw portion 16a provided on its outer peripheral surface is screwed into the inner female screw portion 30 provided on the inner surface of the insertion hole 24 of the joint body 12, so that, as shown in FIG. 1, between the stepped portion provided at the innermost part of the insertion hole 24 of the joint body 12, the ring body 14a portion of the regulating ring 14 can be clamped and fixed. Incidentally, the screw collar 16 is configured such that the stepped portion provided on its outer periphery abuts against the stepped portion provided on the inner peripheral surface of the insertion hole 24 of the joint body 12, so that further screwing can be prevented in a state where the regulating ring 14 is fixed and held with a predetermined tightening force, and its inner hole 16c has an inner diameter large enough for the copper pipe 22 to be inserted therethrough.

[0035] Furthermore, the protruding portion 34 provided at the end of the screw collar 16 on the regulating ring 14 arrangement side suppresses or prevents a large deformation of the locking claw 14b when a pulling force acts on the copper pipe 22 at the tapered inclined surface thereof, so that the pulling prevention force of the copper pipe 22 can be advantageously increased.

[0036] Thus, the screw collar 16 can advantageously suppress or even prevent the locking claw 14b from being greatly deformed by the pulling force of the copper tube 22 while fixing the regulating ring 14. It also contributes to the fixing of the O-ring 18 described later, functions as a guide for the connected copper tube 22, and further has a vibration damping effect of alleviating the transmission of the vibration of the copper tube 22 to the regulating ring 14 and the O-ring 18 as it is.

[0037] The O-ring 18 is a ring with a circular cross-sectional shape made of a rubber material such as IIR or H-NBR. As shown in FIG. 1, two O-rings 18, 18 with different wire diameters but the same inner diameter are arranged in a form sandwiching an annular plate-shaped spacer 36, and are pressed by a pressure bush 20 screwed into the inner peripheral portion of the end of the joint body 12, so as to be located axially outside the insertion hole 24 than the regulating ring 14 and the screw collar 16 and exposed on the inner surface of the insertion hole 24. The inner diameters of the two O-rings 18, 18 are made smaller than the outer diameter of the copper tube 22 so that sealing between the outer peripheral surface of the inserted copper tube 22 can be effectively realized. Here, since the wire diameters of the two O-rings 18, 18 are different, a stepped portion is formed on the inner surface of the joint body 12 so that the inner diameter on the side where the O-ring 18 with a smaller wire diameter is arranged becomes smaller, and the two O-rings 18, 18 can be arranged with the same inner diameter.

[0038] Furthermore, as shown in FIGS. 6(a) and 6(b), the pressure bush 20 is made of the same metal material as the joint body 12, has a thick cylindrical shape, and has an insertion hole 20a sized to insert the copper tube 22 as its inner hole. Also, on the outer peripheral surface of the cylindrical wall portion of the pressure bush 20, there are provided a knurled portion 20b formed by knurling that can be gripped by an operator's hand with a circumferential groove of a predetermined depth in between, and a male screw portion 20c that is screwed and threaded into the female screw portion 28 on the inlet side of the joint body 12. Further, an annular cutout portion 20d is formed at a predetermined depth so as to open at the end face of the pressure bush 20 on the side where the knurled portion 20b is provided, thereby reducing the weight of the pressure bush 20. And when this pressure bush 20 is screwed and threaded into the female screw portion 28 on the inlet side of the joint body 12 at its male screw portion 20c, as shown in FIG. 1, the pressure bush 20 can be attached in a form presenting a small outer shape below the outer shape of the joint body 12, thereby enabling the entire pipe joint 10 to be made more compact.

[0039] And when such a pressure bush 20 has its male screw portion 20c screwed into the female screw portion 28 on the inlet side of the joint body 12 and is attached to the end of the joint body 12 as shown in FIG. 1, the two O-rings 18, 18 arranged via the spacer 36 are pressed at the screwed-in side end face of the pressure bush 20. Thus, the O-rings 18, 18 are accommodated and held at the end of the joint body 12 in a form sandwiched between the screw collar 16 via the spacer 36. Note that in such a state, the two O-rings 18, 18 are not compressed and deformed, so that a large insertion resistance does not occur when the copper tube 22 is inserted.

[0040] Incidentally, when an operator grips a copper pipe 22, which is a pipe to be connected, by hand and inserts and connects it to the pipe joint 10 assembled in the form shown in FIG. 1, the copper pipe 22 is further advanced from the position shown in FIG. 1 and further in FIG. 7(a), inserted into the pipe joint 10, passed through the O-rings 18, 18 and the screw collar 16 from the insertion hole 20a of the pressure bush 20, and then inserted deeper. As a result, the copper pipe 22 is pushed into the regulating ring 14. However, since the locking claws 14b of the regulating ring 14 have a narrow-width portion 32 at their base and can be easily pushed outward, the pushing of the copper pipe 22 into the regulating ring 14 can be easily performed. Then, as the copper pipe 22 further advances, the tip of the copper pipe 22 abuts against the ridge 26 provided on the inner peripheral surface of the joint body 12, whereby the insertion length of the copper pipe 22 is regulated. On the other hand, the locking claws 14b of the regulating ring 14 elastically abut against the outer surface of the copper pipe 22, and the locking claws 14b bite into the outer surface of the copper pipe 22 at the corner portion having a pin angle at the tip. Thus, even when a pulling force acts on the copper pipe 22, a large pulling resistance can be exhibited, and thus, an excellent pulling prevention force for the copper pipe 22 is realized.

[0041] Next, as described above, in a state where the further movement of the copper tube 22 is blocked by the copper tube 22 coming into contact with the ring-shaped protrusion 26 on the inner surface of the joint body 12, the pressure bush 20 is rotated by the operator's hand using the knurled portion 20b for rotation operation provided on its outer peripheral portion, and its screwing is further advanced. Thus, by the pressing force exerted by the contact of the end face of the pressure bush 20, the two O-rings 18, 18 are pressurized and compressed in the axial direction of the insertion hole 24. And thereby, the O-rings 18, 18 are bulged radially inward, and the pressing force against the outer peripheral surface of the copper tube 22 is increased. The O-rings 18, 18 are formed in a substantially rectangular cross-sectional shape as shown in FIG. 7(b) by the pressurizing and compressing action due to the further screwing of the pressure bush 20. And thereby, while expanding the pressure contact area against the outer peripheral surface of the copper tube 22, it is strongly pressure contacted, so that the seal between the outer peripheral surface of the copper tube 22 and the inner surface of the insertion hole 24 can be further enhanced.

[0042] Note that, as the compression ratio of the O-ring 18, generally, about 25% ± 5% which is recognized to be able to exhibit the most effective pressure resistance performance and durability life is adopted. So that such a compression ratio is achieved, in other words, so that the final compression rate (%) is realized, the O-rings 18, 18 are pressed at the end face of the pressure bush 20.

[0043] Therefore, in the pipe joint 10 having such a configuration, when connecting the copper tube 22 which is the pipe to be connected, the operator can easily and simply complete the connection by simply inserting the copper tube 22 held by hand into the insertion hole 24 of the joint body 12 through the insertion hole 20a of the pressure bush 20. Thus, of course, there is no need to use fire as in the case of the conventional soldering method, and there is no need to use a dedicated tool for caulking work as in the conventional caulking method. Therefore, various problems caused by the use of fire and dedicated tools can all be solved.

[0044] Moreover, the insertion operation of the copper tube 22 is to be performed by radially outwardly expanding a plurality of locking claws 14b of the regulating ring 14. Since such locking claws 14b are provided with narrow portions 32 at their bases so that radial outward expansion can be easily achieved, when inserting the copper tube 22 into the regulating ring 14, a large insertion force is not required. Therefore, in addition to the fact that the insertion operation of the copper tube 22 can be easily performed by the operator's hand, since a member such as a guiding cylinder is not necessary, it has also contributed to a reduction in the number of parts.

[0045] Therefore, when the outer diameter of the copper tube 22 is increased, it is necessary to increase its anti-disengagement force. However, even in such a case, the structure of the pipe joint 10 as exemplified can advantageously cope with it. In short, as the diameter of the copper tube 22 to be connected increases, the insertion resistance of such a copper tube 22 increases. However, in order to reduce the insertion resistance of such a copper tube 22, since the bases of the locking claws 14b of the regulating ring 14 are narrow portions 32, due to the presence of the narrow portions 32, a plurality of locking claws 14b of the regulating ring 14 can be easily expanded. Thus, even when the outer diameter of the inserted copper tube 22 is 19 mm or more, its insertion resistance can be effectively reduced, and an insertion operation can be advantageously performed only by the operator's bare hands. And, due to the reduction of this insertion resistance, it also has the feature that the number of regulating rings 14 arranged can be increased.

[0046] Incidentally, the above-described features of the present invention are also obvious from the experimental results shown in Table 1 below. That is, in such an experiment, as the restricting ring 14 used for the pipe joint 10 having the structure shown in FIG. 1, those having the thickness, tip width, narrow width of the base part, and number of the locking claws 14b different as shown in Table 1 below were prepared. Three of them were overlapped and arranged in a three-stage form via spacers. Except that the wire diameters and inner diameters of the two O-rings 18, 18 were the same, a pipe joint 10 having the same structure as that in FIG. 1 was constructed. Then, the insertion resistance of a copper pipe 22 with an outer diameter of 22.22 mm into each pipe joint 10 was examined. In the prepared pipe joint 10, the dimensions of the O-ring 18 were an outer diameter of 31.22 mm, an inner diameter of 21.22 mm, and a thickness of 5.0 mm. Also, the initial compression ratio of the O-ring 18 was 10%, the final compression ratio due to the tightening of the pressure bush 20 was 25%, and the tightening allowance of the pressure bush 20 was 1.0 mm. Then, the insertion resistance of the copper pipe 22 into the pipe joint 10 using the restricting rings 14 of various sizes was examined, and the evaluation results are shown in Table 1 below.

[0047]

Table 1

[0048] As is clear from the results in Table 1 above, in the locking claws 14b of the restricting ring 14, in the pipe joints 10 of Experiment Nos. 1 to 4, in which the narrow width part 32 is provided with the width of the base part as the pinched width rather than the width of the tip part, it is recognized that the insertion resistance is small in each case and the insertion operation can be performed only with the operator's bare hands (evaluation: ○). On the other hand, in the pipe joints 10 of Experiment Nos. 5 and 6, in which the width of the tip part and the width of the base part of the locking claw 14b are the same and the narrow width part 32 is not provided, it is recognized that the insertion resistance becomes large and the insertion operation with only the operator's bare hands is difficult (evaluation: ×).

[0049] In addition, with respect to the pipe joints 10 of Experiment Nos. 1 to 4 used in the above-described insertion resistance evaluation test, each was pulled with a tensile testing machine up to a limit load of 11.7 kN to evaluate the pull-out prevention force. As a result, in none of the pipe joints 10 did the copper pipe 22 come out, and furthermore, it was confirmed that no leakage occurred even when a predetermined pressure was applied in the airtightness test.

[0050] As described above, the representative embodiments of the present invention have been described in detail, but they are merely examples, and it should be understood that the present invention is not construed in any way limited by the specific descriptions of such embodiments.

[0051] For example, in the above-described embodiment, a pipe joint in which two copper pipes 22, which are the pipes to be connected, are linearly connected is described as an example. However, the present invention is by no means limited thereto, and various conventionally known pipe joints with various names used for connecting a pipe for transporting a fluid such as a liquid or a gas to another pipe with a different diameter or to a target device, for example, sockets, adapters, tees, T-shaped, Y-shaped, cross-shaped, 90° elbows, etc. can all be advantageously applied.

[0052] In addition, in the present invention, instead of the pressure bush 20 having a structure as exemplified, a pressure bush 40 having a thinned form as shown in FIG. 8 can also be advantageously used. This pressure bush 40 has a form in which the cylindrical wall portion located on the radially outer side of the relief portion 20d in the previous pressure bush 20 is cut away, and the outer surface of the cylindrical wall portion located on the radially inner side of the relief portion 20d is knurled to form a knurled portion 40b. The operator can grip this knurled portion 40b and rotate the pressure bush 20 by hand. Note that such a pressure bush 40 is provided with an insertion hole 40a in the same manner as the previous pressure bush 20, and a male screw portion 40c that is screwed into the female screw portion 28 on the inner peripheral portion of the end of the joint body 12 is provided on the outer peripheral surface.

[0053] Furthermore, in the exemplary embodiment, 12 locking claws 14b integrally provided on the restricting ring 14 are arranged at predetermined intervals in the circumferential direction. However, the number thereof is appropriately selected in consideration of the insertion resistance of the copper pipe 22, the pulling-out preventing force, etc. Generally, they are provided at equal intervals at a ratio of 6 to 18. In addition, all of such locking claws 14b are formed in a form having a narrow portion 32 at their bases. However, the number of locking claws 14b provided with such a narrow portion 32 is appropriately selected according to the intended insertion resistance. As the number of locking claws 14b provided with such a narrow portion 32 increases, it is possible to reduce the insertion resistance of the copper pipe 22. And regarding the width of the narrow portion 32 provided at the base of the locking claw 14b, in addition to the case where all the narrow portions 32 are provided with the same width, it is also possible to make the widths of the narrow portions 32 different for each locking claw 14b.

[0054] Moreover, regarding the number of restricting rings 14 arranged, it is appropriately selected according to the pipe diameter of the copper pipe 22 to be connected, the pressure of the fluid flowing therethrough, etc., so that effective pressure resistance and pulling-out preventing force can be exhibited. In addition to the single-stage use as in the exemplary embodiment, the three-stage use adopted in the performance evaluation, and further, the use in other multiple stages are all acceptable. When a plurality of restricting rings 14 are used and arranged in multiple stages, in order to avoid mutual interference of the locking claws 14b, in a form in which a spacer with a predetermined thickness is interposed between the respective ring bodies 14a, it will be arranged in the insertion hole 24 of the joint body 12. However, such a spacer is not necessarily required as long as an appropriate interval can be ensured between the adjacent restricting rings 14, 14. For example, it is also possible to form a predetermined gap between them by increasing the thickness of the ring body 14a.

[0055] And in the exemplary embodiment, although O-rings 18 with different wire diameters (thicknesses) are used, it is also possible to use two O-rings 18 with the same wire diameter and inner diameter, thereby enabling advantages such as not having to provide stepped portions with different inner diameters on the inner surface of the joint body 12.

[0056] Also, regarding the manufacturing method of the restricting ring 14, as exemplified, after forming the restricting ring precursor 14' shown in FIG. 3, by bending its locking claw 14b at the narrow portion 32 of the base, in addition to the method of completing the restricting ring 14 in the form shown in FIG. 4, various known techniques can be adopted. For example, by punching out the inner diameter shape of the ring body 14a and the locking claw 14b from a metal plate by pressing, then bending the locking claw 14b at the narrow portion 32 of its base, and then performing a pressing process of punching out the outer diameter shape of the ring body 14a on the metal plate, a method of obtaining the target restricting ring 14, etc., is appropriately adopted.

[0057] In addition, regarding the pipe to be connected, in addition to the exemplary copper pipe 22, a pipe made of a metal material such as an aluminum material made of aluminum or its alloy is also acceptable without any problem. Generally, a pipe made of a soft metal material is advantageously used. Furthermore, regarding the material of the restricting ring 14, it is not limited to the SUS material, and a metal material harder than the pipe to be connected is advantageously adopted.

[0058] In addition, without listing them one by one, the present invention can be implemented in various modified, corrected, improved, etc. forms based on the knowledge of those skilled in the art, and it goes without saying that any such implementation forms belong to the scope of the present invention as long as they do not deviate from the gist of the present invention.

Explanation of Reference Numerals

[0059] 10 Pipe joint 12 Joint body 14 Restricting ring 14a Ring body 14b Locking claw 14' Restricting ring precursor 16 Screw collar 16a External thread portion 16b Tool hole 16c Inner hole 18 O-ring 20 Pressing bush 20a Insertion hole 20b Knurled portion 20c External thread portion 20d Relief portion 22 Copper tube 24 Insertion hole 24a Taper portion 26 Rib 28 Female thread portion on the inlet side 30 Female thread portion on the inner side 32 Narrow portion 34 Protruding portion 40 Pressing bush 40a Insertion hole 40b Knurled portion 40c External thread portion

Claims

1. A regulating ring that is fixedly positioned within the insertion hole of a pipe fitting into which the pipe to be connected is inserted, The device comprises a ring body in the shape of a ring plate of a predetermined width, and a plurality of locking claws that extend integrally from the inner circumference of the ring body toward the center of the ring body and are arranged circumferentially at intervals so as not to come into contact with each other. The locking claws are bent at their base and inclined toward the front side in the insertion direction of the pipe to be connected, and the inner diameter of the regulating ring formed at the tips of the plurality of locking claws is configured to be smaller than the outer diameter of the pipe to be connected, so that when the pipe to be connected is inserted, the locking claws are elastically pushed outward in the radial direction, and are configured to elastically contact the outer surface of the pipe to be connected against the pulling force, thereby preventing pulling out, A restricting ring characterized in that at least one of the plurality of locking claws has a tip portion that extends from its base toward the tip with a constant width and bites into the outer surface of the pipe to be connected, and a narrow portion at the base of the locking claw that is narrower than the width of the tip portion and does not span the ring body, and the ratio (x / y) of the width of the narrow portion (x) to the width of the tip portion (y) is 0.2 to 0.

9.

2. The regulating ring according to Claim 1, characterized in that the thickness of the locking claw is within the range of 0.5 to 1.0 mm and is smaller than the width (x) of the narrow portion.

3. The regulating ring according to claim 1, characterized in that a plurality of locking claws in the regulating ring are spaced apart from each other and arranged in the circumferential direction of the inner circumference of the ring body such that a gap of at least the width (y) is formed between the tips of adjacent locking claws.

4. The restricting ring according to claim 1, characterized in that the narrow portion of the locking claw is formed in a constricted shape in which recesses are formed on both sides in the width direction of the base of the locking claw.

5. A structure to prevent a pipe to be connected from coming loose when inserted into an insertion hole of a pipe joint, The pipe fitting comprises a regulating ring according to any one of claims 1 to 4, fixed within the insertion hole of the pipe fitting; a projection within the insertion hole, positioned outside the regulating ring in the axial direction of the insertion hole, and projecting so as to fit under the bent locking claw of the regulating ring; and a tapered inclined surface formed on the outer circumference of the projection, extending inclined toward the center. A retaining structure characterized in that, when a pulling force is applied to the pipe to be connected, which is inserted into the insertion hole of the pipe fitting, the deformation of the locking claw is suppressed or prevented by the inclined surface.

6. A pipe fitting characterized by comprising a regulating ring as described in any one of Claims 1 to 4.

7. A pipe joint characterized by having the anti-loosening structure described in Claim 5.

8. The pipe fitting according to claim 6 or 7, characterized in that a plurality of the regulating rings are arranged to overlap in the axial direction of the insertion hole with spacers between adjacent regulating rings.

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