JP2007120622A - Surface formation method of grip ring in pipe joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent disconnection of a pipe, by making blade edges, which are formed contiguously to a grip ring, deeply bite into a side surface of the pipe to be inserted/connected with a pipe joint. <P>SOLUTION: The grip ring 17 has L-shaped slits or V-shaped grooves 17b on its right and left sides, and blades 17a are contiguously formed between the L-shaped slits or V-shaped grooves 17b. Tip parts of the blades 17a are the blade edges 17c, and the blade edges 17c of the grip ring 17 bite into the side surface of the pipe (not shown) to prevent the disconnection of the pipe when a casing 15 is fastened. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

In the present invention, the surface of the grip ring used for the pipe joint is subjected to a super-hardening process using a special method, and a series of the grip ring is formed on the surface of a pipe (pipe) to be inserted and connected to the pipe joint. The present invention relates to a method for forming a surface of a grip ring in a pipe joint in which a cutting edge is deeply cut into a side surface of the pipe to prevent the pipe from being removed.

Conventionally, as a first example of this type of pipe joint, there is a technique disclosed in Utility Model Registration No. 3018876 Utility Model Publication shown in FIG. To explain this, the pipe joint 1 includes a sleeve 12 that covers the outer periphery of the pipe, a casing 2 that covers the outer periphery of the sleeve 12, and fastens the sleeve 12 to the outer periphery of the pipe; The grip ring 5 is disposed between the flange 4 provided at the three edges and the sleeve 12, and when the pipe is fastened by the casing 2, the grip ring 5 that bites into the outer periphery of the pipe and fixes the pipe in the pipe joint 1. It consists of a ring fixed inside. The end portions 2a and 2b of the casing 2 arranged opposite to each other are provided with tongue pieces 6a and 6b extending from the end portions 2a and 2b, respectively. The tongue pieces 6a and 6b are formed in the semicircular arc shape. The bracket 4 is formed by folding back to the outside of the flange 4 and fixing its tip to the outer periphery of the flange 4 to form a part of an arc inscribed in the rod washer 7a.

A rod-shaped washer 7a provided with two holes having an inner diameter slightly larger than the outer diameter of the bolts 9, 9 is provided in the bracket 8 formed between the outer periphery of the tongue piece 6a and one end of the flange 4. In a bracket 8 formed between the outer periphery of the other end of the flange 4 and the tongue piece 6b, a bar nut 7b having a screw hole for screwing with the bolts 9, 9 is supported. The brackets 8 and 8 are provided with openings 10 and 10 through which the bolts 9 and 9 are inserted into the rod-shaped washers 7a and the rod nuts 7b. The bolts 9 and 9 are inserted into the rod washer 7a and the rod nut 7b, and screwed into the rod washer 7a and the rod nut 7b. In this way, the brackets 8 and 8 supporting the rod-shaped washer 7a and the rod nut 7b are crushed by a punch or the like to form an indentation portion, and the inner walls of the brackets 8 and 8 are the rod-shaped washer 7a and rod. The rod washer 7a and the rod nut 7b supported in the brackets 8 and 8 are prevented from being displaced in the brackets 8 and 8 so as to be in pressure contact with the nut 7b.

Further, the tip portions of the bolts 9 and 9 may be formed in a conical shape or a head cone shape that gradually changes in cross section in the tip direction, and a screw hole of a rod nut 7b into which the bolts 9 and 9 are inserted. In the vicinity of the inlet, a counterbore-shaped counterbore for guiding the tip of the bolts 9 and 9 into the screw hole of the bar nut 7b is formed. Furthermore, one end of a slide plate 11 that is curved with substantially the same curvature as the inner periphery of the casing 2 is fixed to the inner peripheral surface of one end of the flange 4 that forms the casing 2. When the casing 2 is closed, the ends 2a and 2b of the casing 2 are covered from the inner periphery of the casing 2, and the other end is a free end. The casing 2 is formed as the casing 2 is opened and closed. It arrange | positions in the position which slides with the inner periphery of the other end of the flange 4. FIG.

Further, flanges 4 projecting in the center direction of the casing 2 are provided at the peripheral edges of the both end openings 3 and 3 of the casing 2, and the slide plate 11 and the protection plate fixed to the inner peripheral surface of the flange 4 are also provided. A similar flange 4 is formed, and the flange 4 that is continuous over the entire inner peripheral edge of the opening is formed even when the end portions 2a and 2b of the casing 2 are separated from each other. The casing 2 may have a configuration in which the flange 4 is connected by the hinge, and the substantially cylindrical casing 2 is formed by facing the end portions 2a and 2b of the single flange 4 formed as shown in this example. In addition, by providing one or a plurality of cutouts on the flanges protruding from the peripheral edges 3 and 3 of the opening 2 of the casing 2, the casing 2 can be configured to be openable and closable between the ends 2a and 2b. it can. A cylindrical sleeve 12 is disposed in the casing 2.

A sleeve 12 is made of an elastic material such as synthetic rubber, and is formed in a cylindrical shape having an outer diameter substantially the same as the inner periphery of the casing 2 described above. The outer periphery of the sleeve 12 is formed flat to ensure good adhesion with the inner peripheral surface of the casing 2. The inner peripheral surface of the sleeve 12 is formed in an uneven shape. The concave-convex shape of the inner peripheral surface of the sleeve 12 undulates at the center thereof, and the sleeve 12 is a tongue that is folded back toward the inner center of the sleeve 12 in the vicinity of the openings at both ends of the sleeve 12. A projecting portion is formed on the inner periphery of the sleeve 12 in a substantially trapezoidal shape in the distal direction of the tongue-shaped portion. Reference numeral 5 denotes a grip ring. The grip ring 5 has an annular shape whose center is inclined in the inward direction of the pipe joint 1, and a plurality of teeth 5a are formed at equal intervals on the inner periphery thereof. Yes. The teeth 5a are formed by making a substantially L-shaped cut from the inner periphery of the annular ring and slightly raising a portion surrounded by the cut.

The grip ring 5 has a C-shape with one end cut out, and an auxiliary plate extending one cut-out end is fixed to the cut-out portion, and the other end of the auxiliary plate is fixed. Is slidably brought into contact with the side surface of the other notch end to form the endless ring. The grip ring 5 formed in this way is inserted between the flange 4 of the casing 2 and the open end of the sleeve 12 arranged in the casing 2. When inserting the grip ring 5, it is preferable to place a ring formed by bending a metal wire or the like in a C shape between the grip ring 5 and the flange 4 of the casing 2. By inserting the ring in this way, play in the casing 2 of the grip ring 5 can be prevented.

As a second example of this type of pipe joint, there is a technique disclosed in Japanese Patent Publication No. 2-53670. This technique particularly discloses a clamping ring as a grip ring. To explain this, there is a J-shaped cut out from the inner edge, and the thin plate produced by this cut is bent or twisted somewhat outward from the inner peripheral surface of the truncated cone. The inner edge has a concave profile. This contour forms a V shape with an acute angle. On the other hand, the outer edge is rounded. A rounded outer edge is supported on the corner between the end flange of the housing and the cylindrical portion. The inner edge has a V-shaped profile. The side portion of the contour forms an acute blade edge together with the inner peripheral surface of the frustoconical clamping ring. When the bolt is tightened, the blade edge enters the material at the pipe end. At that time, the pipe material is displaced or turned up. In contrast, the other side of the V-shaped profile forms a pair of stops with the tube material rolled up by the acute angle cutting edge, effectively preventing the cutting edge from further entering the tube material. Housing shrinkage or tightening, sufficient for complete mechanical connection of the tube ends, can be clearly detected when the bolt is tightened.
Registration No. 3018876 Utility Model Gazette Japanese Patent Publication No. 2-53670

The conventional technique has the following problems because it is configured as described in the background art.
That is, in the prior art, as shown in FIGS. 3 (a) and 3 (b), the pipe wall pipe inserted and connected to the pipe joint has a thick wall thickness t1 and an outer surface. Is a carbon steel pipe 13 having a hardness of about HV130, for example, the cutting edge 5a of the grip ring 5 has sufficiently invaded the outer surface of the pipe. However, when the pipe is a pipe with a thin pipe wall, the thickness t2 is thin and the outer surface is a thin stainless steel pipe 13A as shown in FIG. Even if the torque value to be tightened is increased, the tube wall thickness 13 is low and the rigidity is low, and the cutting edge 5a of the grip ring 5 does not bite as shown in FIG. There was a problem that it was formed to dent inward.
And in the conventional technology, according to the austenitic stainless steel as the pipe (pipe), it can be hardened even by the conventional heat treatment, but the corrosion resistance is remarkably impaired and the corrosion resistance is increased. There is a problem that low-cost processing must be performed without impairing the process.

The method of forming the surface of the grip ring in the pipe joint according to the present invention is to raise the grip ring to about HV800 to 1000 by performing a super-curing treatment on the surface of the grip ring. The object of the present invention is to provide a novel grip ring surface forming method that allows the cutting edge to penetrate deeper and has the following configuration and means.

That is, according to the first aspect of the present invention, the step of filling the pot with the electroless nickel and the inert gas, the step of inserting the grip ring having a series of cutting edges in the pot and performing the low temperature heat treatment And a step of welding a hard film on the surface of the grip ring.

According to invention of Claim 2, it consists of the process of making a tungsten carbide infiltrate into the surface of the grip ring which formed the cutting edge in series with the electric discharge machine, and the process of forming a hardened layer on the surface of the grip ring. Features.

According to invention of Claim 3, the process which makes the carbon component included in the grip ring which formed the cutting edge in series by the carbon solid solution diffusion processing method into a solid solution diffusion state, and forms a hardened layer on the surface of the grip ring It is characterized by comprising the steps of:

Since the method of forming the surface of the grip ring in the pipe joint according to the present invention has the above configuration, the following effects are obtained.

That is, according to the first aspect of the present invention, the step of filling the pot with the electroless nickel and the inert gas, the step of inserting the grip ring having a series of cutting edges in the pot and performing the low temperature heat treatment And a method of forming a surface of the grip ring in a pipe joint, comprising the step of welding a hard film to the surface of the grip ring.
Since it was such a structure, since the hard film was welded to the surface of the grip ring by the low-temperature heat treatment process, the cutting edge of the grip ring was improved to a hardness of about HV 800 to 1000, and the connection piping was not deformed. It has the effect of deeply digging into the side and preventing detubation.

According to invention of Claim 2, it consists of the process of making a tungsten carbide infiltrate into the surface of the grip ring which formed the cutting edge in series with the electric discharge machine, and the process of forming a hardened layer on the surface of the grip ring. Provided is a method for forming a surface of a grip ring in a pipe joint.
With this structure, a hardened layer is formed on the surface of the grip ring by an electric discharge machine, so that the cutting edge of the grip ring is improved to a hardness of about HV1300 to 1500, and the connection pipe can be formed without deforming the pipe. It has the effect of deeply digging into the side and preventing detubation.

According to invention of Claim 3, the process which makes the carbon component included in the grip ring which formed the blade edge in series by the carbon solid solution diffusion processing method into a solid solution diffusion state, and forms a hardened layer on the surface of the grip ring A method of forming a surface of a grip ring in a pipe joint.
Since it was such a structure, since the hardened layer was formed on the surface of the grip ring by the carbon solid solution diffusion treatment method, the edge of the grip ring was improved to a hardness of about HV 700 to 800, and the piping was not deformed. There is an effect that the pipe can be deeply cut into the side surface of the connection pipe to prevent the pipe removal.

Embodiments of a method for forming a surface of a grip ring in a pipe joint according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a perspective view showing the structure of a pipe joint according to the present invention, and shows that a grip ring is provided at a pipe joint opening portion.
In explaining the surface forming method of the grip ring in the pipe joint according to the present invention, the pipe joint A will be described first. If the pipe joint A is explained, the outer circumference of the pipe (not shown) inserted into the pipe joint A is covered. A sleeve 14 which covers the outer periphery of the sleeve 14 and fastens the sleeve 14 to the outer periphery of the pipe, and is disposed between the flange 16 and the sleeve 14 provided at the edges 15a and 15b of the both ends of the casing 15. When the pipe (pipe) is tightened by the casing 15, the grip ring 17 that bites into the outer periphery of the pipe and fixes the pipe in the pipe joint A and a ring (not shown) that fixes the grip ring 17 in the casing 15 are formed. . Ends 15c and 15d of the flange 14 arranged in opposition to each other are folded back to the outside of the casing 15 and their tips are fixed on the outer periphery of the casing 15 so as to inscribe the rod-shaped nut 18 and the rod-shaped washer 19. A desired number of brackets 20 that are formed in a part are formed, that is, in the case of FIG. 1, three are formed in pairs.

Further, a rod-shaped washer 19 provided with a hole having an inner diameter slightly larger than the outer diameter of the bolt 21 is supported in the bracket 20... And a rod-shaped nut having a screw hole screwed with the bolt 21. 18 is supported. The brackets 20 are provided with holes for inserting the bolts 21 through the rod-shaped nut 18, and the bolts 21 are inserted into the rod-shaped nut 18 through the holes. Screwed onto the rod-shaped nut 18. In this way, the bracket 20 supported by the rod-shaped nut 18 is crushed on the outer wall with, for example, a punch or the like to form the indented portion 20a, and the inner wall of the bracket 20 is pressed against the rod-shaped washer 19. , The rod-shaped washer 19 supported in the brackets 20 is prevented from being displaced in the brackets 20.

Further, one end of a slide plate 22 that is curved with substantially the same curvature as that of the inner periphery of the casing 15 is fixed to a part of the outer peripheral surface of the sleeve 14 attached to the inner peripheral surface of the casing 15. The plate 22 is disposed at a position that slides with the inner periphery of the flange 16 that forms the casing 15 as the casing 15 is opened and closed. Further, flanges 16 projecting toward the center of the casing 15 are provided at the peripheral edges of both ends 15a and 15b of the casing 15, and the slide plate 22 and the protective plate fixed to the inner peripheral surface of the flange 16 are also provided. A similar flange 16 may be formed. A cylindrical sleeve 14 is disposed in the casing 15.

The sleeve 14 is made of an elastic material such as synthetic rubber, and is formed in a cylindrical shape having an outer diameter substantially the same as the inner periphery of the casing 15 described above. The outer periphery of the sleeve 14 is formed flat to ensure good adhesion with the inner peripheral surface of the casing 15. The inner peripheral surface of the sleeve 14 is formed in an uneven shape 14a. The concave-convex shape 14 a on the inner peripheral surface of the sleeve 14 is undulated in the central portion thereof, and the sleeve 14 is folded back toward the inner central portion of the sleeve 14 in the vicinity of both end openings of the sleeve 14. A tongue portion (not shown) is provided, and projecting portions are formed in the distal direction of the tongue portion, the inner periphery of the sleeve 14 bulging into a substantially trapezoidal shape.

Reference numeral 17 denotes a grip ring. The grip ring 17 has an annular shape whose center is inclined in the inward direction of the pipe joint A, as shown in FIG. A blade 17a is formed. The blade 17a is formed by making a cut 17b in a substantially L shape or V shape from the inner periphery of the annular grip ring 17, and slightly raising a portion surrounded by the cut 17b. The grip ring 17 has a substantially C shape with one end cut out, and the blade 17a has a blade edge 17c on one end surface of the upper surface thereof. The grip ring 17 thus formed is inserted between the flange 16 of the casing 15 and the open end of the sleeve 14 disposed in the casing 15. When inserting the grip ring 17, it is preferable to place a ring formed by bending a metal wire or the like in a C shape between the grip ring 17 and the flange 16 of the casing 15.

Next, a method for forming the surface of the grip ring 17 in the pipe joint A will be described.
As shown in FIG. 2, the grip ring 17 is provided with a substantially L-shaped cut or V-shaped groove 17b on the left and right sides, and a blade 17a is formed in series between the substantially L-shaped cut or the V-shaped groove 17b. Do it. The tip portion of the blade 17a is a blade edge 17c, and when the casing 15 is tightened, the blade edge 17c of the grip ring 17 bites into the side surface of a pipe (pipe) (not shown) to prevent unpipe. And as a surface formation method of the grip ring 17 in the pipe joint A, the step of filling electroless nickel and an inert gas in the pot, and the cutting edge 17c or the blade 17a were formed in series in the pot. It comprises a step of inserting the grip ring 17 and performing a low-temperature heat treatment, and a step of welding a hard film on the surface of the grip ring 17.

Here, electroless nickel is a nickel-phosphorus (5-13%) alloy plating with a surface treatment with many mechanical, electrical and physical properties, and most metal materials, plastics and ceramics. Is possible. Its characteristics are uniform precipitation, regardless of the shape, the throwing power is perfect and within ± 10% of the predetermined film thickness, and the hardness is 500 to 550 HV in the precipitated state, wear resistance. It is superior to electroplating. It has also been found that in heat resistance, it helps prevent surface scale due to high-temperature oxidation, is extremely excellent in adhesion, and is equivalent or superior to pure nickel in corrosion resistance.
However, the cutting edge 17c of the grip ring 17 cannot be made to have a hardness of about HV800 to HV1000 only with such electroless nickel, and it is necessary to fill this electroless nickel with an inert gas.

Next, a first embodiment of the surface forming method of the grip ring 17 in the pipe joint A will be described.
The first embodiment is composed of a step of infiltrating tungsten carbide into the surface of the grip ring 17 formed with a series of cutting edges 17c by an electric discharge machine, and a step of forming a hardened layer on the surface of the grip ring 17. The
Here, as one of the steps for infiltrating the tungsten carbide, the binary alloy plating method of nickel and tungsten is plating with a high content of tungsten and has acid resistance that does not dissolve in hydrofluoric acid or nitric acid. This is a surface treatment method with ultra-high corrosion resistance. Its feature point is a heat-resistant film that has no pinholes, is highly flexible, and is strong against fluorine gas. And although it is about HV600-700 in a precipitation state, it becomes HV1300 or more by hardening. In the salt spray test, there is no change for more than 1000 hours, it has chemical resistance, abrasion resistance and corrosion resistance, high temperature oxidation resistance, non-adhesiveness, and release property, industrial chrome plating It is an environmentally friendly plating method as an alternative to the above.

According to the first embodiment, a hardened layer having a high hardness on the surface of the grip ring 17 is formed, and a hardened film of about 20 to 30 μm is formed on the work surface. A hardened layer having a thickness of about 10 to 20 μm is also formed inside the work. Moreover, the surface of the grip ring 17 melts well with the workpiece material, and forms a high-quality cured layer with a thickness of 10 to 20 μm inside the workpiece material. A hard film of about 10 to 20 μm is formed on the work surface. Also, the film on the workpiece surface can be easily removed. And the lifetime of the said grip ring 17 improved significantly and the hard layer could be formed by mixing a very hard ceramic type material into the inside of the surface of the said grip ring 17. Moreover, a hardened layer is formed inside the surface of the grip ring 17 and can be used in combination with quenching treatment or plating coating treatment. In addition to improving wear resistance, it has simple equipment and simple operation procedures. The surface of the grip ring 17 could be formed in a short time.

Next, a second embodiment of the method for forming the surface of the grip ring 17 in the pipe joint will be described.
In the second embodiment, first, a carbon component included in the grip ring 17 in which the blade edges 17c are formed in series by the carbon solid solution diffusion treatment method is brought into a solid solution diffusion state, and a hardened layer is formed on the surface of the grip ring. It is comprised by the process to do.

The above-mentioned carbon solid solution diffusion treatment method is a surface hardening treatment method for austenitic stainless steel, and the hardened layer itself formed on the surface of the grip ring 17 is formed with a stable austenite structure, and wear resistance and toughness. The surface of the grip ring 17 can be formed with corrosion resistance and corrosion resistance. And it became clear that the hardness of the surface of the grip ring 17 is not less than HV800 and has non-magnetic characteristics, and the surface hardness of the grip ring 17 equivalent to the nitrogen treatment method can be obtained, and the fatigue strength is remarkably improved. .

As described above, according to the method for forming a surface of a grip ring according to the present invention based on the above-described embodiment, Example 1 or Example 2, the surface of the grip ring is super-cured so that the grip ring is HV800. It was raised to about ˜1000, and the feature point that the cutting edge 17c could be deeply penetrated into the side surface of the pipe even with the conventional tightening torque value could be revealed.

It is a perspective view which shows the structure of the pipe joint which applied the grip ring produced with the surface formation method of the grip ring which concerns on this invention. It is a perspective view which shows the shape of the grip ring applied to the pipe joint which concerns on this invention. It is explanatory drawing which shows the state which bites into the piping (pipe) in which the grip ring in a prior art is inserted and arrange | positioned at a pipe joint, Comprising: (a) is a state before biting a grip ring into piping of a thick pipe wall Explanatory drawing which shows a state, (b) is explanatory drawing which shows the state which the grip ring digged into piping of a thick pipe wall, (c) is an explanation which shows the state before digging the grip ring into piping of a thin pipe wall FIG. 4D is an explanatory view showing a state where the thin pipe wall pipe is curved when the grip ring is bitten into the pipe of the thin pipe wall. It is a perspective view which shows the structure of a pipe joint when the grip ring formed by the prior art is applied to a pipe joint.

Explanation of symbols

14 Sleeve 15 Casing 15a Casing one opening 15b Casing other opening 15c Casing end 15d Casing end 16 Flange 17 Grip ring 17a Grip ring blade 17b Grip ring substantially L-shaped cut (V-shaped groove) )
17c Grip ring cutting edge 18 Bar nut 19 Bar washer 20 Bracket 20a Bracket indentation 21 Bolt 22 Slide plate A Pipe joint

Claims (3)

Filling the pot with electroless nickel and inert gas, inserting a grip ring with a series of cutting edges into the pot and performing low-temperature heat treatment, and welding a hard film on the surface of the grip ring A method for forming a surface of a grip ring in a pipe joint, characterized by comprising the steps of: A grip ring in a pipe joint comprising a step of infiltrating tungsten carbide into the surface of a grip ring formed with a series of cutting edges by an electric discharge machine and a step of forming a hardened layer on the surface of the grip ring. Surface forming method. The carbon component included in the grip ring formed with a series of cutting edges by a carbon solid solution diffusion treatment method is a step of forming a solid solution diffusion state, and a step of forming a hardened layer on the surface of the grip ring. A method for forming a surface of a grip ring in a pipe joint.

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