JP4385313B2 - Sleeve type fitting - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pipe joint for connecting a resin pipe or a thin metal pipe, and more particularly to a sleeve type pipe joint for connecting a pipe by press-fitting a sleeve fitted on a joint body in the pipe axis direction.
[0002]
[Prior art]
Conventionally, resin pipes formed of polyolefin resins such as polyethylene, polybutene, and polypropylene, which are used as fluid transport pipes such as gas pipes and water pipes, are joined by various methods. Specifically, a mechanical type pipe joint is used in which a nut is screwed into a joint body, and the joint body and the packing or biting ring mounted in the nut are compressed to be connected. According to this mechanical-type pipe joint, the biting ring is assembled on the outer surface of the pipe end, and then the nut is fastened to the joint main body with a wrench to make the connection. The above-mentioned mechanical type pipe joint has the disadvantage that the pipe insertion confirmation as to whether or not the pipe has been securely inserted cannot be performed after the completion of the construction, and it is difficult to confirm the tightening degree of the nut, and the pipe connection part It was easy for variations in performance to occur. Therefore, even if there is insufficient pipe insertion, nut tightening or a biting ring installation error, these shortcomings cannot be detected by a short-term leak test performed immediately after construction, and long-term use is not possible. Occasionally, the connecting pipe may come off or leak. To solve these problems, it consists of a joint body having a core part that is inserted and supported on the inner surface of the connection pipe, and a diameter-reducing member that is attached to the outer surface of the connection pipe that is extrapolated to the core part to reduce the diameter. The diameter-reducing member has a sleeve portion that can be reduced in diameter, a thin-walled shearing portion, and a shearing portion that is compressed in the axial direction so that the inner surface fits on the outer surface of the sleeve portion, and the sleeve portion is A sleeve type pipe joint composed of an annular portion with a reduced diameter has been proposed, and its practical application has been studied (see Patent Document 1). This sleeve type pipe joint is composed only of a main body and a sleeve, and the manufacturing cost is reduced compared to the conventional joint structure combining three or more parts, and the connection work can be easily performed with a small tool. There is no variation in strength, connection confirmation after construction is easy, and there are many advantages that troublesome work such as parts assembly work and pipe expansion work at the time of pipe connection work is eliminated.
[0003]
Sleeve-type pipe joint described in Patent Document 1, although in theory it is possible to connect the tube by sliding (compression) of the sleeve to the tube axis direction, the leak applying vibration to the connection portion When the presence / absence was confirmed, there was a case in which the sleeve once tightened loosened by vibration, and fluid leaked there. Therefore, in order to prevent the sleeve from loosening, a sleeve type pipe joint has been proposed in which a locking function for the large diameter portion is added to the outer periphery of the small diameter portion of the sleeve (see Patent Document 2). The structure of this sleeve type pipe joint will be described with reference to FIG. In the pipe joint 10, the sleeve 200 is assembled to the end portion of the joint body 11 by engaging the latching portion 23 at one end of the resin sleeve 200 in the groove 15 of the joint body 11. At the end of the joint body 11, a cylindrical portion 12 that fits the inner diameter of the pipe 30 to be connected is formed, and on the outer peripheral surface thereof, a plurality of sawtooth-shaped convex portions 13 are formed, and The end surface of the tube 30 is configured to come into contact with the end surface 14 on the back side of the cylindrical portion 12. The sleeve 200, which is formed in a substantially cylindrical shape as a whole, is coupled to the end portion of the thin portion 201 through a thin portion 201 having a hook portion 23 at one end portion and a flange portion 22 at a central portion and a projection 204. And a thick part 203. A circumferential groove 202 is formed in a portion adjacent to the flange portion 22 of the thin wall portion 201, and an inner circumferential surface of the thick wall portion 203 rises from the protrusion 204 toward the end surface opposite to the stepped portion 205. It is tapered so as to be a slope. According to this pipe joint 10, the sleeve 200 is compressed in the axial direction, and the thick portion 203 is pushed in until the stepped portion 205 comes into contact with the flange portion 22, whereby the inner peripheral surface of the thick portion 203 is the thin portion 201. The pipe 30 is compressed and the connection is completed.
[0004]
[Patent Document 1]
JP 2002-39467 A (page 3-4, FIG. 1)
[Patent Document 2]
JP 2003-113978 A (page 2-3, FIG. 5)
[0005]
[Problems to be solved by the invention]
The sleeve-type pipe joint described in Patent Document 2 compresses the sleeve 200 in the axial direction, thereby cutting (shearing) a thick-walled portion (large) by a projection 204 having a small cross-sectional area provided at the center of the sleeve 200. When the diameter portion 203 rides on the outer periphery of the thin portion (small diameter portion) 201, a part of the inner peripheral surface of the thick portion 203 fits into the circumferential groove 202, so that the thick portion 203 is piped from the thin portion 201. It is considered that there is no axial deviation. However, when the thick part 203 passes through the apex of the thin part 201 in front of the circumferential groove 202, plastic deformation occurs and the inner diameter is expanded. That is, since the inner peripheral surface of the thick portion 203 is in local contact with the maximum outer diameter portion (vertex) of the thin portion 201, the contact pressure is increased at the contact portion, and large plastic deformation occurs. In addition, since the inner peripheral surface of the thick portion 203 is inclined upward toward the end portion, the function of pressing the thin portion 201 by the thick portion 203 is weakened, that is, the pressing force is eased. There is. Therefore, even if the sleeve 200, the pipe 30 and the joint body 11 are apparently tightened due to the shearing of the sleeve 200, when the axial compression of the sleeve 200 is finished, the tightening is loosened, so that vibration is generated in the pipe connection portion. When added, there is a problem that fluid leakage occurs.
[0006]
Accordingly, an object of the present invention is to provide a sleeve type pipe joint that can solve the above-mentioned problems and can join pipes with a simple operation and that does not cause fluid leakage from the connection portion over a long period of time. is there.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a joint body having a cylindrical portion housed in a connection pipe, a small-diameter portion and a coupling portion arranged around the connection pipe and capable of contacting the outer peripheral surface of the connection pipe. And a sleeve formed in a substantially cylindrical shape including a large-diameter portion coupled to the small-diameter portion via, and by compressing the sleeve in the axial direction, the coupling portion is sheared, and the large-diameter portion In the sleeve-type pipe joint in which the connecting pipe is clamped between the cylindrical portion and the sleeve, the small diameter portion includes a conical portion that guides the large diameter portion and a shaft extending therefrom. and has a ring portion extending in a direction, the large diameter portion have a pressing portion and it than with large-diameter stepped portion in contact with the conical portion and the annular portion, in the middle of the conical portion, the When the large diameter portion and the small diameter portion are compressed, the stepped portion is locked. And it is characterized in Rukoto raised portion is formed.
[0008]
Sleeve-type pipe joint of the present invention has the above configuration, the coupling portion by compressing the sleeve in the axial direction is sheared, a large-diameter portion after the large-diameter portion, separated from the small diameter portion is over the conical portion Since the contact area with the small diameter portion is expanded, the deformation of the large diameter portion is within the elastic limit, and the end of the large diameter portion is locked to the small diameter portion, so that the joint body, the tube and the sleeve are mutually strong. Tightened . Therefore, the occurrence of leakage can be prevented even when vibration is applied to the piping.
[0009]
Furthermore, the sleeve-type pipe joint of the present invention, in the middle of the serial cone, upon compressing said large diameter portion and said small-diameter portion, since the stepped portion that has projections for engagement are formed , it is possible to a large-diameter portion is more reliably hold the large diameter portion engages with the protrusion is stepped portions when moving to the annular portion over the conical portion to the small diameter portion.
[0010]
In the sleeve-type pipe joint according to the present invention, it is preferable that the small diameter portion has a flange portion that contacts the end surface of the large diameter portion on the side opposite to the coupling portion. According to is this, the operation of only the large diameter portion to compress the sleeve until it hits the flange, it is possible to connect the connecting pipe and fittings.
[0011]
In the sleeve-type pipe joint according to the present invention, it is preferable that the small-diameter portion has at least one slit portion extending from the free end to the front of the coupling portion. According to is this, the rigidity of the small-diameter portion is weakened moderately, even when applied by compression tool size and weight, small diameter portion is reliably compressed without disruption of the small diameter portion (in the circumferential direction separated) Thus, the pipe and the joint can be firmly connected. Furthermore, it can be visually confirmed whether or not the end surface of the connecting pipe is in contact with the joint body through the slit portion.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a partial cross-sectional view showing a state immediately before a connecting pipe is inserted into a joint and compression of the sleeve is started, and FIG. 2 is a perspective view showing the appearance of the sleeve. FIG.
In FIG. 1, reference numeral 10 denotes a pipe joint, which is composed of a joint body 11 and a sleeve 20, and a pipe 30 to be connected is interposed therebetween. A cylindrical portion 12 to be inserted into the inner diameter side of the pipe 30 is provided at the end of the joint body 11, and a convex strip 13 having a sawtooth cross section is formed on the outer peripheral surface thereof. The tube 30 is inserted between the joint main body 11 and the sleeve 20 until the end surface 31 abuts on the end surface 14 provided at the back of the cylindrical portion 12, and further, the sleeve 20 is inserted into the groove portion 15 formed at the back of the end surface 14. The latching | locking part 23 formed in the free end side inner periphery is fitted.
[0013]
As shown in FIGS. 1 and 2, the sleeve 20 is a single resin member formed entirely in a substantially cylindrical shape by, for example, injection molding, and has a substantially annular large diameter having an end surface 202 and a stepped surface 25. It has the part 24, the thin coupling | bond part 26 formed in the one end part of the internal peripheral surface, the small diameter part 21 extended in an axial direction from there, and the collar part 22 formed in the middle of the small diameter part. The inner peripheral surface (pressing portion) 205 of the large-diameter portion 24 is formed to have a substantially equal diameter along the axial direction and a slightly larger diameter than the inner peripheral surface 205 in order to compress the small-diameter portion. A stepped portion 203 having a diameter larger than that of the inner peripheral surface 205 is formed at the right end portion of 205 (see FIG. 1). The small diameter portion 21 includes a conical portion 27 formed so as to have an upward slope from the base of the coupling portion 26 and an annular portion 29 having an outer peripheral surface extending in the axial direction in parallel to the inner peripheral surface. A projection 204 is provided in the middle to form a step. A latching portion 23 is formed on the inner periphery of the small-diameter portion 21 on the free end side. By inserting the latching portion 23 into the groove portion 15 of the main body 11, the sleeve 20 is assembled to the joint main body 11 by its elastic deformation. It is done. The dimensions of the small-diameter portion 21 and the large-diameter portion 24 are set according to the deformation amount (compression amount) of the small-diameter portion 21 required for connecting the pipe 30. In order to prevent the large-diameter portion 24 from protruding greatly when riding on the small-diameter portion 21, the length of the large-diameter portion 24 in the longitudinal direction of the tube is set to a dimension substantially equal to the distance between the uneven surface 25 and the flange portion 22. It is desirable that In order for the small-diameter portion 21 of the sleeve 20 to be easily elastically deformed, a plurality of (or even one) slit portions 28 extending from the latching portion 23 to the front of the uneven surface 25 are provided, and the width of the slit portion 28 is The length or the number of the lengths is set according to the mechanical strength of the sleeve 20 and the compressive force necessary to fix the tube 30 to the joint body 11. The resin forming the sleeve 20 is desirably a thermoplastic resin having a tensile strength of 60 MPa or more. Examples of such a resin include PA6 (tensile strength: 70 to 85 MPa), POM (tensile strength: 62 to 70 MPa). ), Engineering plastics such as PPS (tensile strength: 75 MPa).
[0014]
Connection between the pipe joint 10 and the pipe 30 shown in FIGS. 1 and 2 is performed in the following procedure. First, in the state shown in FIG. 1, the large-diameter portion 24 and the small-diameter portion 21 are stepped by sandwiching the end surface 201 of the flange portion 22 and the end surface 202 of the large-diameter portion 24 with, for example, a pliers-like compression tool (not shown). It is sheared by the coupling portion 26 provided at the base of the surface 25, the inner peripheral surface of the large diameter portion 24 gets over the conical portion 27, and the large diameter portion 24 moves in the axial direction until the stepped surface 25 hits the flange 22. FIG. 3 shows a state where the connection of the pipe 30 is completed. At the same time as the large diameter portion 24 moves in the axial direction, the conical portion 27 and the annular portion 29 are elastically deformed by the moved large diameter portion 24 (radial direction). Compressed). Along with this, the tube 30 is elastically deformed (compressed in the radial direction), so the tube 30 is pressed against the cylindrical portion 12 of the joint body 11 and the cutting edge of the ridge 13 of the cylindrical portion 12 on the inner surface of the tube 30. As a result, the pipe 30 is clamped and fixed between the sleeve 20 and the joint body 11. At this time, since the annular portion 29 exists in front of the conical portion 27, the surface pressure generated between the inner peripheral surface (pressing portion) 205 of the large diameter portion 24 and the conical portion 27 and the annular portion 29 is The large-diameter portion 24 does not show a large value locally in a part of the length direction as in the conventional case, and even if the inner diameter of the large-diameter portion 24 is expanded, the small-diameter portion 21 is pressed toward the tube 30 to be contracted. Force is generated. In addition, since the stepped portion 203 formed on the inner peripheral surface of the end of the large-diameter portion 24 is engaged with the projection 204 provided in the middle of the conical portion 27, the small-diameter portion 21 and the large-diameter portion 24 are firmly engaged with each other. . Therefore, since the state in which the small diameter portion 21 is compressed in the radial direction by the large diameter portion 24 is maintained for a long period of time, even if vibration is applied to the connection portion due to fluid pressure fluctuation or the like after connecting the pipe 30 to the joint body 11, The large diameter portion 24 of the sleeve 20 can be prevented from slipping out from the small diameter portion 21 in the tube axis direction. Further, since the small diameter portion 21 is provided with the flange 22, the connecting work can be completed by pressing the stepped surface 25 until it hits the flange 22. Furthermore, by providing the slit portion 28 in the sleeve 20, the rigidity of the small diameter portion 21 becomes smaller than that of the large diameter portion 24 of the sleeve 20, and the diameter can be easily reduced. By providing such a slit portion 28 in the sleeve 20, it is possible to visually confirm whether or not the end portion 31 of the tube 30 is in contact with the tube end abutting surface 14 from the outside of the pipe joint 10. Insufficiency can be easily prevented.
[0015]
In the pipe joint 10, since the sleeve 20 can be assembled to the joint body 11 in advance, the pipe can be connected to the joint simply by inserting the pipe into the joint and compressing the sleeve in the axial direction. Since the work for assembling the parts becomes unnecessary, the chance of occurrence of construction defects is reduced.
[0016]
【The invention's effect】
As described above, according to the pipe joint of the present invention, when the sleeve is compressed in the axial direction, the small diameter portion and the large diameter portion are firmly engaged, and the small diameter portion is compressed in the radial direction by the large diameter portion. Since it is maintained over a long period of time, even when vibration occurs in the pipe, the large diameter portion does not come out of the small diameter portion, and thus there is no fluid leakage, and a highly reliable pipe connection portion can be obtained. Further, according to the pipe joint of the present invention, since the sleeve can be assembled to the joint body in advance, it is possible to perform a simple operation of simply compressing the sleeve using a tool after inserting the pipe into the joint, thereby preventing poor construction. It is possible. Further, according to the pipe joint of the present invention, the rigidity of the small diameter portion of the sleeve can be reduced, so that the thrust required for compression is reduced, and piping can be performed with a small tool.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a state immediately before connection of a sleeve type pipe joint according to an embodiment of the present invention.
FIG. 2 is a perspective view showing a sleeve used in the sleeve type pipe joint of FIG. 1;
FIG. 3 is a cross-sectional view showing a state after the connection of the sleeve type pipe joint of FIG. 1 is completed.
FIG. 4 is a cross-sectional view showing a state immediately before connection of a sleeve-type pipe joint of a prior application.
[Explanation of symbols]
10: pipe joint, 11: joint body, 12: cylindrical part, 13: convex part, 14: end face, 15: groove part, 20: sleeve, 21: small diameter part, 22: collar part, 23: latching part, 24 : Large diameter portion, 25: Stepped surface, 26: Coupling portion, 27: Conical portion, 28: Cutting portion, 29: Ring portion, 201, 202: End surface, 203: Stepped portion, 204: Protruding portion 205: Inside Peripheral surface (pressing part) 30: connecting pipe, 31: end surface

Claims (1)

A joint body having a cylindrical portion built in the connecting pipe, a small diameter portion arranged around the connecting pipe, and capable of contacting the outer peripheral surface of the connecting pipe and a large diameter coupled to the small diameter portion via a coupling portion A sleeve formed in a substantially cylindrical shape including a portion, and by compressing the sleeve in the axial direction, the coupling portion is sheared, the large diameter portion rides on the small diameter portion, and the connecting pipe is In the sleeve type pipe joint sandwiched between the cylindrical portion and the sleeve,
The small diameter portion has a conical portion for guiding the large diameter portion and an annular portion extending in the axial direction therefrom,
The large diameter portion have a pressing portion and it than with large-diameter stepped portion in contact with the conical portion and the annular portion,
Wherein the middle of the conical portion, said upon compressing a large diameter portion and the small diameter portion, the sleeve-type pipe joint portion with said stage, characterized that you have projections for locking is formed.

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