Pressure-resistant 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 in pipe connection work at pipe sites such as in the ceiling space. Therefore, when connecting these pipes to be joined and the joint, various pipe joint structures have been proposed that mechanically connect the two without using fire such as conventional brazing.

[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 the claw of the lock ring is made to bite into its outer peripheral surface, thereby regulating the pulling out of the inserted pipe body. A pipe joint structure has been disclosed.

[0005] However, in the pipe joint structure of the type where the pipes to be connected are inserted, 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 sealing 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 sealing 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 onto the joint body may become loose, resulting in leakage or the pipe to be connected falling off.

[0006] In addition, in Japanese Patent 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 a ring-shaped holding member is further inserted. In a state where the end of the opening of the joint body is caulked inward, a joint structure is disclosed in which the holding member is caulked and fixed. 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 peripheral surface of the pipe, preventing the pipe from coming off. 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 fully 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 realized 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 an air-conditioning device 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. In addition, 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 hardened or highly strengthened, the insertion resistance of the connected pipe becomes excessive, and there arises a problem that it becomes difficult to insert it manually by an 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. Therefore, it was extremely difficult to insert the connected pipe by the bare hands of an operator.

[0008] Therefore, the applicant of the present application, as a pressure-resistant pipe joint that enables connection work using the normal force of an operator even for a pipe body to be connected with a large outer diameter of the pipe, in Japanese Patent Application Laid-Open No. 2022-29434, a plurality of locking claws of a regulating ring disposed for position fixation in the insertion hole of the joint body are expanded radially outward, and a predetermined guiding cylinder body is disposed 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 such a pipe body to be connected and pushed into the inner part of the insertion hole. By doing so, 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. A structure was proposed. As a result, the work of fitting and arranging such a pipe body to be connected into the regulating ring can be carried out relatively easily, simply, and quickly by the hands of an operator.

[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 an increase in cost based on this cannot be avoided. And in addition to that, it is necessary to insert a guiding cylinder body in advance into the insertion hole of the joint body of the pipe joint so as to expand a plurality of locking claws of the regulating ring radially outward and arrange them. 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 that is fixedly disposed in the insertion hole and positioned; a sealing means composed of an O-ring that is disposed outside the axial direction of the insertion hole with respect to the regulating ring, is exposed in the insertion hole, contacts the outer surface of the connected pipe body inserted into the insertion hole, and seals the space between the outer surface of the connected pipe body and the inner surface of the insertion hole; and a cylindrical pressure bush having 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, the O-ring is pressurized and compressed in the axial direction of the insertion hole, so that the O-ring bulges 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 addition, according to one of the desirable embodiments of the pressure-resistant pipe joint according to the present invention, the regulating ring is abutted against a stepped portion formed on the inner surface of the insertion hole by a screw collar member screwed to a screw portion provided on the inner surface of the insertion hole, and is 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 portion on the side where the pipe to be connected of the joint body is inserted, so as 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 of the position where the restricting ring is disposed, 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.

Advantages 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 a position-fixed manner within the insertion hole of the joint body, 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 shape 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 with respect to the restricting ring can be effectively reduced. Thus, without using the guiding cylinder body previously proposed by the applicant of the present application, 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 hands of the operator. 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 exhibited by such a tip portion biting into the outer surface of the pipe to be connected. Therefore, in addition to being able to exhibit sufficient pulling-out resistance force, by further screwing in the pressure bush screwed to the end portion of the joint body, an 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 further without the need to expand the locking claws of the regulating ring with an induction cylinder, under low insertion resistance, simply by the operator's bare hands inserting the target pipe to be connected through the insertion hole provided in the pressure bush of the pipe joint and then inserting it into the insertion hole of the joint body, the connection between the pipe to be connected and the pipe joint is completed. Therefore, 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 having a large outer diameter of 19 mm or more and up to 38.1 mm, the feature that their connection can be advantageously performed can be demonstrated.

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, Fig. 1 shows a representative example of a pressure-resistant pipe joint according to the present invention. Here, for the left half thereof, it is shown in a longitudinal sectional form. 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 part not shown on the right side in Fig. 1) has the same structure as the left side part 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 a member 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 end portions thereof, the pipe bodies (here, copper pipes 22) to be connected are inserted and are to be connected. Therefore, insertion holes 24, 24 for the pipe bodies (copper pipes 22) are provided, which open at both end portions respectively. And between these insertion holes 24, 24, a ring-shaped protrusion 26 as stopper means, which protrudes from the inner peripheral surface at a predetermined height so as to be located at the central part in the axial direction of the joint body 12, is integrally formed on the inner peripheral surface 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 come into contact therewith.

[0028] Also, the insertion holes 24 of the joint body 12 are formed to open in a stepped form in which the diameter gradually increases toward the end portion 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-side 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 giving the smallest inner diameter, a tapered portion 24a composed of an inclined surface that inclines toward the end opening portion of the joint body 12 and has an enlarged diameter is provided, whereby 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 width: x that is narrower than the width: y on the tip side. Such a restricting ring precursor 14' can be easily manufactured, for example, by punching a predetermined metal plate having elasticity with a press.

[0030] And in such a restricting ring precursor 14', a plurality of its locking claws 14b are bent at the narrow-width portion 32 of their bases to the front side in the insertion direction of the copper pipe 22, which is the pipe to be connected, 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, whereby 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. Thus, with respect to the pulling-out behavior of the copper pipe 22 connected by the pipe joint 10, the restricting ring is made of a hard metal material having elasticity, such as SUS301, which can exhibit elastic characteristics, so that the locking claws 14b can bite into, in other words, can catch on, the outer surface of the copper pipe 22. Accordingly, the locking claws 14b are made 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 claw 14b of the regulating ring 14 is 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 portion of the locking claw 14b is formed as a pin angle at the corner portion on the side in contact with the copper pipe 22, it will bite into or catch on the outer surface of the copper pipe 22. Therefore, even when 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 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 portion 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 portion 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 apparent from FIGS. 5(a) and 5(b), the screw collar 16 is composed 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 face 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 such tool holes 16b are 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, such screw collar 16 is screwed, by a rotation operation with a tool using its tool hole 16b, the male screw portion 16a provided on its outer peripheral surface, into the inner female screw portion 30 provided on the inner surface of the insertion hole 24 of the joint body 12. Thus, 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 restricting ring 14 can be clamped and fixed. Incidentally, this screw collar 16 is such that, when the stepped portion provided on its outer peripheral portion abuts against the stepped portion provided on the inner peripheral surface of the insertion hole 24 of the joint body 12, further screwing-in can be prevented while the restricting ring 14 is fixed and held with a predetermined tightening force, and its inner hole 16c has an inner diameter of a size through which the copper tube 22 can be inserted.

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

[0036] In this way, 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, and also contributes to the fixing of the O-ring 18 described later. It also 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 restricting ring 14 and the O-ring 18 as it is.

[0037] The O-ring 18 is a ring having 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 having different wire diameters but the same inner diameter are in a form sandwiching an annular plate-shaped spacer 36, and are screwed into the inner peripheral portion of the end of the joint body 12. By being pressed by the pressure bush 20, it is located axially outside the insertion hole 24 with respect to the restricting ring 14 and the screw collar 16, and is arranged so as to be 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 the 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 in its inner hole that is large enough to insert the copper pipe 22. Also, on the outer peripheral surface of the cylindrical wall portion of the pressure bush 20, there are provided a knurled portion 20b that is knurled for gripping by an operator's hand with a circumferential groove of a predetermined depth in between, and a male screw portion 20c that is screwed into and engaged with 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 to 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 engaged with 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, whereby the entire pipe joint 10 can 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 of being sandwiched between the male collar 16 via the spacer 36. Incidentally, in such a state, the two O-rings 18, 18 are not compressed and deformed, and therefore, a large insertion resistance does not occur when the copper pipe 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 the copper pipe 22 is inserted deeper. As a result, the copper pipe 22 is pushed into the restricting ring 14. However, since the locking claws 14b of the restricting ring 14 have a narrow-width portion 32 at their bases and can be easily pushed outward, the pushing of the copper pipe 22 into the restricting ring 14 can be easily performed. Then, due to further advancement of the copper pipe 22, the tip of the copper pipe 22 abuts against the protrusion 26 provided on the inner peripheral surface of the joint body 12, whereby the insertion length of the copper pipe 22 is restricted. On the other hand, the locking claws 14b of the restricting 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 formed as the pin angle at the tip thereof. 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 abutting against the ring-shaped protrusion 26 on the inner surface of the joint body 12, the pressure bush 20 is rotated by the hand of an operator using the knurled portion 20b for rotation operation provided on its outer peripheral portion, and the screwing is further advanced. Thus, by the pressing force exerted by the abutment 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. As a result, the O-rings 18, 18 bulge radially inward, increasing the pressing force against the outer peripheral surface of the copper tube 22. The O-rings 18, 18 assume a substantially rectangular cross-sectional shape as shown in FIG. 7(b) due to the pressurizing and compressing action caused by the further screwing of the pressure bush 20. By this, while expanding the pressure contact area against the outer peripheral surface of the copper tube 22, the O-rings 18, 18 are 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, generally, as the compression ratio of the O-ring 18, about 25% ± 5% which is recognized to be able to exhibit the most effective pressure resistance performance and durability life is adopted. The O-rings 18, 18 are pressed at the end face of the pressure bush 20 so that such a compression ratio, in other words, the final compression rate (%) is achieved.

[0043] Therefore, in the pipe joint 10 having such a configuration, when connecting the copper tube 22 which is the tube to be connected, the operator can simply hold the copper tube 22 by hand and insert the tube end portion into the insertion hole 24 of the joint body 12 through the insertion hole 20a of the pressure bush 20, and easily and simply complete the connection. As a result, there is no need to use fire as in the case of the conventional soldering method, and of course, 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 the 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 can contribute to the reduction of the number of parts.

[0045] Therefore, when the outer diameter of the copper tube 22 is increased, it is necessary to increase its anti-loosening 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 the 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] In addition, 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 different thicknesses, tip widths, narrow widths at the base, and numbers of the locking claws 14b as shown in Table 1 below were prepared. Three of them were overlapped and arranged in a three-stage form via spacers. A pipe joint 10 having the same structure as that of FIG. 1 was constructed except that the wire diameters and inner diameters of the two O-rings 18 and 18 were the same. 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 part 32 is provided with the width at the base as the sandwiching width rather than the width at the tip, it is recognized that the insertion resistance is small in each case, and the insertion operation can be performed only by the bare hands of the operator (evaluation: ○). On the other hand, in the pipe joints 10 of Experiment Nos. 5 and 6, in which the width at the tip and the width at the base of the locking claw 14b are the same and the narrow part 32 is not provided, it is recognized that the insertion resistance becomes large and the insertion operation can be difficult only by the bare hands of the operator (evaluation: ×).

[0049] Also, regarding the pipe fittings 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 fittings 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 interpreted in any way limited by the specific descriptions of such embodiments.

[0051] For example, in the above-described embodiment, a pipe fitting 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 fittings with different 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 be advantageously applied.

[0052] Also, 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 relieved 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 relieved portion 20d is knurled to form a knurled portion 40b. An 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 an external thread portion 40c that is screwed into the female thread 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, twelve 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 rate of 6 to 18. Also, all of such locking claws 14b are formed in a form in which their bases are narrow portions 32. However, the number of locking claws 14b provided with such narrow portions 32 is appropriately selected according to the intended insertion resistance. As the number of locking claws 14b provided with such narrow portions 32 increases, it is possible to reduce the insertion resistance of the copper pipe 22. And also 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 width of the narrow portion 32 different for each locking claw 14b.

[0054] Furthermore, also 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, use in other multiple stages are all acceptable. When arranging in multiple stages using a plurality of restricting rings 14, 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 with each other 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 enjoying advantages such as not having to provide stepped portions with different inner diameters on the inner surface of the joint body 12.

[0056] Also, in 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 methods 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, and 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 and the like are appropriately adopted.

[0057] In addition, for 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, the material of the restricting ring 14 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, and improved forms based on the knowledge of those skilled in the art. And it goes without saying that any such embodiments 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 male screw part 16b tool hole 16c inner hole 18 O-ring 20 pressure bush 20a insertion hole 20b knurled part 20c male screw part 20d relieved part 22 copper tube 24 insertion hole 24a tapered part 26 protrusion 28 female screw part on the inlet side 30 female screw part on the inner side 32 narrow part 34 protruding part 40 pressure bush 40a insertion hole 40b knurled part 40c male screw part

Claims

1. A pressure-resistant pipe joint having: a cylindrical joint body having an insertion hole at at least one end portion side, into which a metal pipe to be connected is inserted and fixed; a plurality of elastically deformable locking claws that bite into the outer surface of the metal pipe to be connected inserted into the insertion hole and prevent the pulling out of the pipe to be connected, and are provided at predetermined intervals in the circumferential direction of the insertion hole; a restricting ring that is fixedly disposed in the insertion hole and is located axially outside the insertion hole with respect to the restricting ring, is disposed so as to be exposed in the insertion hole, contacts the outer surface of the pipe to be connected inserted into the insertion hole, and seals between the outer surface of the pipe to be connected and the inner surface of the insertion hole; a sealing means comprising an O-ring; and a cylindrical pressure bush having an insertion hole for the pipe to be connected formed axially, which is screwed to the end portion of the joint body on the side where the pipe to be connected is inserted, and by advancing such screwing, the O-ring is pressurized and compressed in the axial direction of the insertion hole, so that the O-ring bulges radially inward to enhance the pressure-bonding property to the outer surface of the pipe to be connected. The regulating ring has an annular plate-shaped ring body with a predetermined width that is fixedly held within the insertion hole of the joint body. The plurality of locking claws are arranged in the circumferential direction so as to integrally extend from the inner peripheral portion of the ring body toward the center of the ring body and at intervals where they do not contact each other. Further, 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 body to be connected. And at least one of the plurality of locking claws has a narrow-width portion that does not span the ring body and is narrower than the width of the tip portion that bites into the outer surface of the pipe body to be connected at its base. The narrow-width portion is bent at the narrow-width portion and inclined toward the front side in the insertion direction of the pipe body to be connected. Further, such a locking claw has a tip portion that extends with a constant width from the base side toward the tip, and the ratio (x / y) of the width (x) of the narrow-width portion provided at the base to the width (y) of the tip portion is configured to be 0.2 to 0.

9. When the pipe body to be connected is inserted into the insertion hole of the joint body and pushed into the regulating ring, the plurality of locking claws are elastically pushed and expanded radially outward, and the locking claws are elastically abutted against the outer surface of the pipe body to be connected. A pressure-resistant pipe joint characterized by this.

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

3. The pressure-resistant pipe joint according to claim 1, characterized in that the pressure bush is screwed and attached to a screw portion provided on the inner peripheral portion of the end of the joint body on the side where the pipe body to be connected is inserted.

4. The pressure-resistant pipe joint according to claim 3, characterized in that the outer peripheral surface of the pressure bush is knurled, and the screwing operation of the pressure bush can be performed by an operator's hand by gripping the knurled portion.

5. The pressure-resistant pipe joint according to claim 1, characterized in that 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.

6. Stopper means is provided on the inner surface of the insertion hole on the inner side from the arrangement position of the regulating ring, and the connected pipe body inserted into the insertion hole is brought into contact therewith to prevent its movement. The pressure-resistant pipe joint according to claim 1, characterized in that it is provided.

7. Insertion holes are respectively provided at both ends of the joint body, and the connected pipe bodies are inserted and fixed to these insertion holes by using the regulating ring, the sealing means, and the pressurizing bush, respectively. The pressure-resistant pipe joint according to claim 1, characterized in that two connected pipe bodies are connected.

8. The pressure-resistant pipe joint according to any one of claims 1 to 7, characterized in that the connected pipe body is a large-diameter pipe body having an outer diameter of 19 mm or more.

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