JP4332839B2 - 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. Generally, 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 having an annular portion with a reduced diameter has been proposed, and its practical application has been studied (see Patent Document 1 and Patent Document 2). In this sleeve type pipe joint, the main components of the pipe joint are the main body and the sleeve, and the manufacturing cost is reduced compared to the conventional joint structure in which three or more parts are combined, and connection work can be performed with a small tool. It can be easily performed, there is no variation in connection 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]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-349481 (page 3-4, FIG. 1)
[Patent Document 2]
JP 2002-39467 A (page 3-4, FIG. 1)
[0004]
[Problems to be solved by the invention]
The above-mentioned sleeve-type pipe joint can theoretically be connected to the pipe by sliding (compressing) the sleeve in the pipe axis direction. It was found that there were still points to be improved. For example, in order to make it easy to connect with a small tool, after the sleeve and the annular part are separated by the shearing part, the annular part quickly rides on the sleeve part, so that the small diameter part is reduced in diameter. However, if the small diameter part can be easily reduced in diameter, for example, by thinning the small diameter part, the small diameter part is divided into a plurality of parts in the course of the sleeve compression process. Problems such as inability to connect are likely to occur. For this reason, in the conventional sleeve-type pipe joint, in order to make a reliable connection, a relatively large rigidity is given to the small diameter portion, and compression is performed with a large tightening force using a large tool.
[0005]
Accordingly, an object of the present invention is to provide a sleeve-type pipe joint that solves the above-described problems and can reliably join the connecting pipe and the joint with a small tool.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a joint body having a cylindrical portion inserted into the inner periphery of a connecting pipe, and a contact small diameter portion and a thin wall disposed on the outer peripheral surface of the connecting pipe. A sleeve formed in a substantially cylindrical shape including a large-diameter portion coupled to the small-diameter portion via a portion, and by compressing the sleeve in the axial direction, the thin-walled 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 by the portion riding on the small diameter portion, the small diameter portion has one axial direction from one end to the other end. More than one slit part is provided, and one or more axial grooves are provided in a shorter range than the slit part on the outer periphery of the small diameter part, and the small diameter part has a flange on the opposite side of the thin part. The axial groove extends from the flange portion to the thin wall portion. And it has a structure that is formed before.
[0007]
The present invention comprises only a joint body and a sleeve, the small diameter portion on which the large diameter portion rides is provided with one or more slit portions along the axial direction from one end to the other end, and 1 on the outer periphery of the small diameter portion. Since there are more axial grooves, the sleeve is cut (sheared) in the axial direction using a small compression tool, and then the thin part is cut (sheared) and separated into two parts. Since the large diameter portion rides on the outer periphery of the small diameter portion and the small diameter portion on the inner peripheral side is reliably reduced in diameter, the connecting pipe is firmly sandwiched and connected between the joint body and the sleeve. In addition, since the axial groove provided separately from the slit portion is formed in a range shorter than the slit portion, the small diameter portion is prevented from being divided during compression.
[0008]
Further, the small diameter portion has a flange portion on the opposite side of the thin portion, the axial groove so formed from the flange portion to the front of the thin portion, appropriate rigidity can be imparted to the small-diameter portion Therefore, even when a small and lightweight compression tool is used, the small-diameter portion is reliably compressed without breaking the small-diameter portion, and the pipe and the joint can be firmly connected.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view of a sleeve type pipe joint according to an embodiment of the present invention, showing a state immediately before a connecting pipe is inserted into the joint and compression of the sleeve is started, and FIG. 2 is used in FIG. FIG. 3 is a perspective view of the sleeve, FIG. 3 is a sectional view showing a state in which the sleeve is compressed in the sleeve type pipe joint of FIG. 1, and FIG. 4 is a front view showing a state in which the sleeve type pipe joint is sandwiched with a compression tool.
[0010]
In FIG. 1, reference numeral 10 denotes a pipe joint, which is composed of a joint body 11 and a sleeve 20 provided around the joint body 11, and a connecting pipe 30 is interposed between the two. A cylindrical portion 12 having an outer diameter that can be inserted into the inner periphery of the connection pipe 30 is formed at one end of the joint body 11, and the back end surface 14 of the cylindrical portion 12 faces the end surface 31 of the connection pipe 30, On the outer peripheral surface of the cylindrical portion 12, a plurality of cross-sectional sawtooth-shaped ridges 13 are provided. A circumferential groove 15 that receives the end of the sleeve 20 is formed at a predetermined distance from the rear end surface 14 of the cylindrical portion 12 (on the side away from the connecting tube 30).
[0011]
As shown in FIG. 2, the sleeve 20 is a member formed in a substantially cylindrical shape as a whole, and has a large diameter portion 24 having an end face 202 and a stepped portion 25 along the direction in which the connecting pipe 30 is inserted, and an inner periphery thereof. It has a thin-walled portion 26 provided on the side, and a small-diameter portion 21 including a conical portion 27 and a flange portion 22 formed so as to have an upward slope from there to the maximum-diameter portion 211. The small-diameter portion 21 is formed on an inclined surface having an upward slope from the end surface 201 of the flange portion 22 toward the end portion, and a circumferential protrusion 23 that is engaged with the groove 15 is provided on the inner periphery of the end portion. . The small diameter portion 21 is symmetrically provided with a pair of slit portions 28 extending from one end (free end) to the other end (stepped portion 25) along the axial direction. A pair of axial grooves 29 extending from the flange portion 22 to the front of the stepped portion 25 are symmetrically provided on the outer periphery of the small diameter portion 21 in the middle of the slit portion 28 in the circumferential direction. The sleeve 20 is attached to the joint body 11 using elastic deformation by pushing the circumferential protrusion 23 into the circumferential groove 15.
[0012]
By compressing the sleeve 20 in the axial direction with the compression tool 40 from the state shown in FIG. 4, the connecting pipe 30 and the joint 10 are connected as shown in FIG. That is, the sleeve 20 is sheared by the thin-walled portion 26 by sandwiching the end surface 201 of the flange portion 22 of the sleeve 20 and the end surface 202 of the large-diameter portion 24 with a tool and pressing until the flange 22 hits the stepped portion 25. The conical portion 27 is inserted into the inner circumference of the 24 while being reduced in diameter. Accordingly, the connecting tube 30 is pressed (reduced in diameter) between the sleeve 20 and the cylindrical portion 12, and the cutting edge of the ridge 13 provided on the outer periphery of the cylindrical portion 12 bites into the inner periphery of the connecting tube 30. The connecting pipe 30 and the joint 10 are firmly connected. Since the sleeve 20 is provided with the slit portion 28 and the axial groove 29 in the small diameter portion 21, the rigidity of the small diameter portion 21 is smaller than that of the large diameter portion 24 and can be easily reduced in diameter. Moreover, the slit portion 28 is provided over the entire length of the small diameter portion 21, but the axial groove 29 is provided in a range shorter than the slit portion 28, thereby preventing the small diameter portion 21 from being divided during compression. Can do. The object of the present invention can be achieved if each of the cut portion 28 and the axial groove 29 is at least one. However, in order to further reduce the size of the tool and reliably prevent the division of the small diameter portion when the sleeve is compressed, a plurality of slit portions 28 and a plurality of axial grooves 29 are formed in the small diameter portion 21 as shown in FIG. It is preferable that the slits 28 and the axial grooves 29 are arranged alternately in the circumferential direction. The number of the slits 28 and the axial grooves 29 depends on the size of the connecting pipe, the material of the sleeve, and the like. What is necessary is just to set suitably. The tool shown in FIG. 4 is an example of a manual type tool, and is used when the connecting pipe has a small size (outer diameter of 13 mm or less). The sleeve compression tool is not limited to the manual type, but may be an electric type or a hydraulic type. In any type, the smaller the thrust required to connect the joint, the smaller the tool size and weight. It is desirable because it can be reduced.
[0013]
In the present invention, in order to reduce the thrust required for the above-described shearing and climbing, it is desirable that the sleeve is made of plastic. Specific materials include PPA (polyphthalamide), PA (polyamide), and POM. A plastic having a dynamic friction coefficient of 0.4 or less, such as (polyacetal) or PPS (polyphenylene sulfide) to which a fluororesin is added, is suitable. This dynamic friction coefficient is measured with a thrust type tester under the conditions of P (surface pressure) = 0.98 MPa (10 Kgf / cm ² ) and V (sliding speed) = 0.3 m / S) by preparing a sample of the same material. It is the value. For example, when a thrust at the time of connecting a polybutene pipe having an outer diameter of 13 mm to a joint having the joint body 11 assembled with the PPA sleeve 20 was measured, it was confirmed that the shear thrust was 3100 N and the maximum ride load was 3800 N. On the other hand, when a metal sleeve is assembled to the joint body, the mechanical strength (especially the longitudinal elastic modulus) of the sleeve is large, so the thrust required for shearing and climbing is about 12000 N in the case of a polybutene pipe with an outer diameter of 13 mm. In the case of a polybutene tube having a diameter of 27 mm, it was confirmed that it would be about 25000 N. When the pipe joint of the present invention is applied to a hot water supply pipe, the sleeve is known as a heat-resistant {heat-resistant temperature> 150 ° C. and tensile strength> 0.98 MPa (10 Kgf / cm ² )} plastic. It may be made of plastic such as PSF (polysulfone), PPS (polyphenylene sulfide), PPO (polyphenylene oxide), PPE (modified polyphenylene ether), PPSF (polyphenylsulfone), etc. These plastics have a coefficient of dynamic friction of 0. Since it is as large as about 45 to 0.7, a lubricant (for example, a solid lubricant such as fatty acid, soap, wax, molybdenum disulfide, organic compound) on the surface of the conical portion 27 of the sleeve 20 or the inner peripheral surface of the large diameter portion 24. Is preferably applied. Thereby, the maximum thrust at the time of boarding can be made small.
[0014]
In the sleeve type joint according to the embodiment of the present invention, since the sleeve 20 is assembled in advance to the joint body 11, the pipe is connected by simply inserting the pipe into the joint and compressing the sleeve 20 in the axial direction. Can do. Therefore, it is not necessary for the pipe construction company to assemble the parts, and the chances of construction errors are reduced. Further, whether or not the tube is surely inserted into the joint can be confirmed by the fact that the end portion 31 of the tube 30 abuts against the tube end contact surface 14 from the outside by the slit portion 26 of the sleeve 20. Inadequate tube insertion is prevented. Furthermore, since the completion of the compression operation of the sleeve 20 can be confirmed by the butting of the flange portion 22 and the stepped portion 25 of the sleeve 20, the confirmation operation by the administrator after construction can be easily performed.
[0015]
【The invention's effect】
As described above, according to the present invention, the small diameter portion of the sleeve assembled to the joint main body is provided with one or more slit portions along the axial direction from one end to the other end, and the outer periphery of the small diameter portion. Since one or more axial grooves are provided in the pipe, the pipe and the joint can be connected with a small operating force. Therefore, it is possible to obtain a highly reliable piping construction using a small tool.
[0016]
Furthermore, according to the present invention, the following effects can be obtained. By assembling the sleeve to the joint body in advance, the pipe connection work at the pipe construction site is simply inserting the pipe into the joint and compressing the sleeve using a tool, making the work easy and reducing the possibility of construction errors. . In addition, when connecting, the sleeve as a single member is sheared at the center due to compression by the tool and functions as two parts, so the manufacturing cost can be reduced compared to the structure in which two parts are made in advance, The time and labor of assembly can be saved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a sleeve-type pipe joint according to an embodiment of the present invention, showing a state immediately before a connecting pipe is inserted into the joint and compression of the sleeve is started.
FIG. 2 is a perspective view of a sleeve used in FIG.
3 is a partial cross-sectional view of the sleeve-type joint of FIG. 1 after completion of pipe connection.
FIG. 4 is a front view of a tool used to construct the pipe joint of the present invention.
[Explanation of symbols]
10: Pipe joint, 11: Joint body, 12: Cylindrical part, 13: Convex line part, 14: End face on the pipe end, 15: Groove part 20: Sleeve, 21: Small diameter part, 22: Gutter part, 23: Projection part, 24: Large diameter part,
25: Stepped portion, 26: Thin portion, 27: Conical portion, 28: Cutting portion 29: Axial groove, 201, 202: End face, 211: Maximum diameter portion 30: Connection pipe, 31: End portion 40: Tool

Claims (1)

A joint main body having a cylindrical portion built in the connecting pipe, and a large diameter disposed around the connecting pipe and connected to the small diameter section via a small diameter portion and a thin portion that can contact the outer peripheral surface of the connecting pipe. A sleeve formed in a substantially cylindrical shape including a portion, and by compressing the sleeve in the axial direction, the thin-walled portion is sheared, and the large-diameter portion rides on the small-diameter portion, whereby the connecting pipe In the sleeve-type pipe joint that is sandwiched between the cylindrical portion and the sleeve,
The small-diameter portion is provided with one or more slit portions along the axial direction from one end to the other end, and one or more axial grooves are provided in a range shorter than the slit portion on the outer periphery of the small-diameter portion ,
The small-diameter portion has a flange on the opposite side to the thin portion, and the axial groove is formed from the flange to the front of the thin portion .

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