JP4332287B2 - Fitting for soft pipe - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a soft pipe joint.
[0002]
[Prior art]
FIG. 5 is a partial sectional view showing a use state of a conventional soft pipe joint. This joint rusts the tubular body 1 by covering the outer peripheral surface 12 and the end surface 13 of the metallic tubular body 1 formed by the end of the pipe material or the short tubular joint member with the resin layer 2. It is. In addition, on the inner peripheral surface of the end portion of the cylindrical body 1, there are provided engaging portions 14 including a plurality of ring-shaped protrusions 14 a formed inwardly at a plurality of axial positions at predetermined intervals. In addition, an annular recessed portion 15 is provided in the axially inner portion of the portion where the engaging portion 14 is formed, and the resin layer 2 extends in the axial direction starting from the end face 13 of the cylindrical body 1. A protruding cylindrical protruding portion 21 is provided.
[0003]
When a soft pipe such as a resin pipe is connected to the joint to ensure the sealing performance of the connection portion, the annular packings 3 and 4 are respectively held inside the recessed portion 15 and the protruding portion 21, After the soft tube 5 is inserted into the tube, the distal end portion of the soft tube 5 is expanded by expanding the diameter of the cylindrical stiffener 6 previously inserted into the distal end portion of the soft tube 5 using a predetermined jig. . In this way, the projection 14a of the cylindrical body 1 bites into the tube wall at the distal end portion of the soft tube 5 so that the soft tube 5 is prevented from being pulled out, and the recessed portion 15 of the cylindrical body 1 is inserted into the recessed portion 15 of the cylindrical body 1 as shown in the figure. The held packing 3 is pressed and compressed by the soft tube 5 and the cylindrical body 1 to be in close contact with them, and the packing 4 held inside the protruding portion 21 of the resin layer 2 is the soft tube. 5 and the projecting portion 21 are pressed against each other and in close contact with each other in a compressed state to ensure the sealing performance of the connection portion.
[0004]
In Japanese Utility Model Laid-Open No. 1-174690, the packing 4 described in FIG. 5 is omitted, and the thickness of the protruding portion 21 is increased so that the inner peripheral surface of the protruding portion contacts the outer peripheral surface of the soft tube. There is a description of the joints in contact.
[0005]
Furthermore, in JP-A-4-145293, a packing is interposed between an end portion of a cylindrical body whose entire outer surface is covered with a resin layer and a soft tube, and the packing is connected to the cylindrical body and the cylindrical body. There is a description of a joint that is pressed by a soft pipe that has been inserted and expanded in diameter.
[0006]
[Problems to be solved by the invention]
However, in the joint of FIG. 5, the protruding portion 21 forms one end portion of the resin layer 2, and the protruding portion 21 is required to extend in the axial direction starting from the end surface 13 of the cylindrical body 1. Therefore, when the packing 4 is pushed in the diameter-expanding direction by the soft pipe 5 having an enlarged diameter and pressed against the protruding portion 21, the protruding portion 21 may be depending on the magnitude of the pressing force at that time. The protruding part 21 is peeled off from the end face 13 of the cylindrical body 1 and expanded in diameter to obtain a contact pressure between the protruding part 21 and the soft tube 5 and the packing to maintain a satisfactory sealing property. There was a risk that it would be impossible. Regarding the joint described in the above-mentioned Japanese Utility Model Laid-Open No. 1-174690, the protruding portion is peeled off from the end face of the cylindrical body by being pushed in the expanding direction by the soft tube having the protruding portion having an increased diameter. There was a risk of doing so.
[0007]
Further, in the joint described in FIG. 5 and the joint described in JP-A-4-145293 described above, a packing (such as packing 4 in FIG. 5) is interposed between the end of the joint and the soft pipe. Therefore, the packing was necessary extra.
[0008]
The present invention has been made under the above circumstances, and is for a soft pipe capable of ensuring the sealing performance of the facing portion between the end of the joint and the soft pipe inserted into the joint without using a packing. The object is to provide a joint.
[0009]
Another object of the present invention is to provide a joint for soft pipes that does not cause the resin layer to peel off from the end face of the cylindrical body due to the effect of expanding the diameter of the soft pipe inserted into the cylindrical body.
[0010]
[Means for Solving the Problems]
The soft tube joint according to the present invention is a tube of a soft tube in which an outer peripheral surface and an end surface of a metal tubular body are covered with a resin layer, and the diameter is increased by being inserted into the tubular body. An engaging portion is provided that engages with the wall and prevents the soft tube from being removed. Such a joint includes the joint described in FIG.
[0011]
In the present invention, the cylinder that extends from the end surface covering portion that covers the end surface of the cylindrical body to the end inner peripheral surface side of the cylindrical body to cover the end inner peripheral surface of the cylindrical body on the resin layer A seal portion is formed on the inner peripheral surface of the inner peripheral surface covering portion to which the outer peripheral surface of the soft tube that has been inserted into the cylindrical body and expanded in diameter is in close contact. ing. And the said inner peripheral surface coating | coated part has the thickness pressed by the edge part of the said cylindrical body, and the soft pipe | tube expanded by inserting in the said cylindrical body. On the inner peripheral surface of the cylindrical body, an annular recessed portion is provided in the axially inner portion of the portion where the engaging portion is formed, and an annular packing is held inside the recessed portion.
[0012]
According to this joint, the inner peripheral surface covering portion extended from the end surface covering portion of the resin layer exhibits a function equivalent to that of the packing 4 described in FIG. That is, the outer peripheral surface of the soft pipe inserted into the cylindrical body and expanded in diameter is in close contact with the seal portion of the inner peripheral surface of the inner peripheral surface covering portion, so that the end of the joint is inserted into the joint. In addition, the sealing property at the location facing the soft tube is ensured without using packing. This effect is further achieved by the fact that the inner peripheral surface covering portion has a thickness that is pressed by the end portion of the cylindrical body and the soft tube that is inserted into the cylindrical body and has an enlarged diameter. Prominently demonstrated. In addition, since the inner peripheral surface covering portion is formed by extending from the end surface covering portion of the resin layer to the inner peripheral surface side of the end portion of the cylindrical body, an injection molding method or the like is employed to form a cylindrical shape. When the resin layer is coated on the outer peripheral surface and the end surface of the body, there is an advantage that an inner peripheral surface covering portion can be formed together.
[0013]
It is desirable that the seal portion includes a ring-shaped protrusion protruding from the inner peripheral surface of the inner peripheral surface covering portion. This protrusion can be formed, for example, in an inwardly pointed shape. According to this, since the protrusion of the inner peripheral surface covering portion comes into contact with the outer peripheral surface of the expanded soft tube, and the contact state becomes a line contact state or a state close to the line contact state, the protrusion and the soft tube A high sealing property is imparted to the contact portion with the outer peripheral surface of the. In addition, since the pressing force due to the expanded soft tube is concentrated to some extent on the formation area of the protrusion, it becomes difficult to apply a large pressing force to the entire seal portion, so the end surface covering portion of the resin layer and the inner peripheral surface covering portion are folded back. A situation in which compressive stress is excessively applied to the boundary portion of the shape is less likely to occur, which helps to prevent a situation in which a crack or a crack occurs in the boundary portion of the folded shape and the long-term sealing property is impaired.
[0014]
The protrusion may be provided at one location in the axial direction of the inner peripheral surface covering portion, or may be provided at two or more locations spaced in the axial direction of the inner peripheral surface covering portion. . When the protrusions are provided at two or more places, the protrusions are crushed by the pressing force of the expanded soft tube as compared with the case where the protrusions are provided at only one place (the above-mentioned action (above) It is difficult to cause a situation in which the compressive stress is not excessively concentrated on the boundary portion.
[0015]
The engagement portion may be a protrusion that protrudes inward from the inner peripheral surface of the cylindrical body and can be eaten into the tube wall of the soft tube that is inserted into the cylindrical body and has an enlarged diameter. Such protrusions are also provided in the conventional joint described in FIG.
[0016]
It is desirable that the inner surface and the outer surface of the boundary portion between the inner peripheral surface covering portion and the end surface covering portion are smooth surfaces having no bent corners. According to this, the compressive stress does not act excessively on the boundary portion due to the characteristics of the outer surface and the inner surface of the boundary portion between the inner periphery covering portion and the end surface covering portion.
[0017]
It is desirable that the inner peripheral surface covering portion has a function of preventing the resin layer from being separated from the cylindrical body by engaging with the inner peripheral surface of the end portion of the cylindrical body. Such a peeling prevention function of the inner peripheral surface covering portion is as described above. The inner peripheral surface covering portion extends from the end surface covering portion covering the end surface of the cylindrical body to the inner peripheral surface side of the cylindrical body. This is a function that is naturally exhibited by being formed into a cylindrical shape. In order to enhance this function, it is effective to increase the length of the cylindrical inner peripheral surface covering portion .
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a partial cross-sectional view showing a use state of a soft pipe joint according to the present invention, and FIG. 2 is an enlarged view of a main part of FIG. FIG. 3 is an enlarged view of a main part of a modification, and FIG. 4 is an enlarged view of a main part of another modification.
[0019]
As shown in FIG. 1, in this joint, the outer peripheral surface and the end surface of the metal cylindrical body 1 are covered with the resin layer 2, and the cylindrical body 1 is inserted into the cylindrical body 1 and expanded. An engaging portion 14 is provided for engaging with the tube wall of the diameter of the soft tube 5 to prevent the soft tube 5 from being pulled out, and the engaging portion 14 includes a plurality of inwardly-pointed protrusions 14a. In these respects, the joint of FIG. 1 corresponds to the joint described in FIG.
[0020]
However, this joint differs from the joint described in FIG. 5 in the following points. That is, as shown in an enlarged view in FIG. 2, the end surface covering portion 22 that covers the end surface 13 of the cylindrical body 1 on the resin layer 2 that covers the outer peripheral surface of the cylindrical body 1 and the end surface 13. A cylindrical inner peripheral surface covering portion 23 extending from the end portion inner peripheral surface side of the cylindrical body 1 to cover the end inner peripheral surface 16 of the cylindrical body 1, and this inner peripheral surface covering The seal portion 24 is formed on the inner peripheral surface of the portion 23 so that the outer peripheral surface 51 of the soft tube 5 inserted into the cylindrical body 1 and expanded in diameter is in close contact therewith. In FIG. 2, the thickness of the end surface covering portion 22 of the resin layer 2 is indicated by a symbol T1, and the length of the inner peripheral surface covering portion 23 is indicated by a symbol L1.
[0021]
In the illustrated joint, the seal portion 24 of the inner peripheral surface covering portion 23 described above refers to a portion where the outer peripheral surface 51 of the soft pipe 5 whose diameter has been expanded is in close contact. Therefore, as shown in FIG. 2, when the ring-shaped protrusions 26 protruding inwardly with a gap are formed at two positions in the axial direction of the inner peripheral surface 25 of the inner peripheral surface covering portion 23, Of course, the protrusion 26 is included, the protrusion 26 is crushed by the expanded soft tube 5, or the protrusion 26 recedes in the radially outward direction due to the flexibility of the resin, so that the outer peripheral surface 51 of the soft tube 5 is formed. The flat inner peripheral surface 25 is also included when closely contacting the inner peripheral surface 25 flat in the axial direction.
[0022]
The inner peripheral surface covering portion 23 has a thickness that is pressed by the end portion of the tubular body 1 and the soft tube 5 that is inserted into the tubular body 1 and has an enlarged diameter. Therefore, when the inner peripheral surface covering portion 23 is pushed in the diameter increasing direction by the expanded soft tube 5, the inner peripheral surface covering portion 23 is pressed by the end portion 17 of the cylindrical body 1 and the soft tube 5. Therefore, the outer peripheral surface 51 of the soft tube 5 is brought into close contact with the seal portion 24 on the inner peripheral surface of the inner peripheral surface covering portion 23, whereby the end portion of the joint (specifically, the end portion 17 of the tubular body 1). ) And the soft tube 5 inserted into the joint, the sealing property is ensured without using packing.
[0023]
As can be seen in FIG. 2, the protrusion 26 is positioned on the inner side in the axial direction than the end face 13 of the metallic cylindrical body 1. Further, even if the inner peripheral surface covering portion 23 is pushed in the radially outward direction by the soft pipe 5 whose diameter has been expanded, the inner peripheral surface covering portion 23 is backed up from the outside by the end portion 17 of the metallic cylindrical body 1. Therefore, the inner peripheral surface covering portion 23 does not warp in the diameter expansion direction. Therefore, a high sealing property is ensured at the facing portion. Particularly in this embodiment, since the protrusion 26 is included in the seal portion 24, the protrusion 26 always comes into contact with the outer peripheral surface 51 of the soft pipe 5 whose diameter has been expanded. In this case, if the inner peripheral surface covering portion 23 having the protrusions 26 and the soft tube 5 are made of the same hardness, the soft tube 5 is expanded in diameter and the outer peripheral surface 51 of the soft tube 5 protrudes. Since the protrusion 26 is crushed as shown in FIG. 2 by pressing 26, the surface pressure at the contact portion between the protrusion 26 and the outer peripheral surface 51 of the soft tube 5 increases, and the portion has an extremely high sealing performance. Is granted. Here, the hardness of the protrusion 26 may be appropriately determined in relation to the hardness of the tube wall of the soft tube 5 so that the protrusion 26 bites into the tube wall of the soft tube 5.
[0024]
As can be seen from FIG. 2, at the boundary portion 28 connecting the inner peripheral surface covering portion 23 and the end surface covering portion 22, the inner surface 28 a and the outer surface 28 b of the boundary portion 28 are smooth and have no bent corners. It is a serious aspect. Specifically, the inner surface 28a of the boundary portion 28 is an arcuate curved surface, and the outer surface 28b of the boundary portion 28 is formed by a tapered surface 28c and arcuate curved surfaces 28d and 28e on both sides thereof. . When the inner surface 28a and the outer surface 28b of the boundary portion 28 are formed in such a shape, even if the inner peripheral surface covering portion 23 is pushed in the diameter expansion direction by the expanded soft tube 5, the compressive stress is applied to the boundary portion 28. Does not act excessively, and cracks and cracks are less likely to occur at the boundary portion 28. This effect becomes even more remarkable when the protrusion 26 is included in the seal portion 24. That is, when the protrusion 26 of the inner peripheral surface covering portion 23 comes into contact with the outer peripheral surface 51 of the expanded soft tube 5, the pressing force by the expanded soft tube 5 is concentrated to some extent on the formation portion of the protrusion 26 and the seal portion. This is because a large pressing force is less likely to be applied to the entirety of 24, so that a situation in which a compressive stress acts excessively on the boundary portion 28 is less likely to occur. Furthermore, when the projections 26 are provided at two locations as in the illustrated example, the projections 26 are crushed by the pressing force of the soft tube 5 whose diameter has been expanded compared to the case where the projections 26 are provided only at one location. As a result, the situation in which the above action (the action that the compressive stress is not excessively concentrated on the boundary portion) is impaired is less likely to occur.
[0025]
In this embodiment, the inner peripheral surface covering portion 23 is formed in a cylindrical shape having a length L1. Therefore, the inner peripheral surface covering portion 23 exerts a function of preventing the resin layer 2 from being separated from the cylindrical body 1 by being engaged with the end inner peripheral surface 16 of the cylindrical body 1.
[0026]
The inner peripheral surface coating layer 23 can be molded together with the outer peripheral surface coating layer 29 (shown by the length symbol L2 in FIG. 2) of the resin layer 2 and the end surface coating layer 22 when injection molding is performed. It is. Even when the inner peripheral surface covering layer 23 is formed in close contact with the end inner peripheral surface 16 of the cylindrical body 1, it is tapered in a state where it is separated from the end inner peripheral surface 16 of the cylindrical body 1 as shown in FIG. You may form in the shape of a circle. If it is formed in a tapered shape as shown in FIG. 3, the soft tube (not shown) inserted therein acts so that its inner peripheral surface covering layer 23 is tightened. The degree of adhesion with the layer 23 is increased.
[0027]
In the above embodiment, the protrusions 26 are included in the seal portion 24. However, as shown in FIG. 4, this point is that the seal portion 24 is formed only by the flat inner peripheral surface of the inner peripheral surface covering portion 23. It may be formed. In this way, the one effect exerted by the presence of the protrusion 26 described above, that is, the effect of remarkably avoiding excessive concentration of compressive stress on the boundary portion 28 is somewhat reduced. The point can be solved in consideration of other factors such as the material of the resin layer 2 and the shape of the boundary portion 28.
[0028]
In FIG. 1 to FIG. 4, for simplicity of explanation, the same or corresponding parts as those explained in FIG. 1 to 4, the same or corresponding parts are denoted by the same reference numerals.
[0029]
【The invention's effect】
As described above, according to the soft pipe joint of the present invention, it is possible to ensure the sealing performance of the facing portion between the end of the joint and the soft pipe inserted into the joint without using packing. Further, there is no possibility that the resin layer is peeled off from the end face of the cylindrical body due to the influence of expanding the diameter of the soft tube inserted into the cylindrical body.
[Brief description of the drawings]
FIG. 1 is a partial sectional view showing a use state of a soft pipe joint according to the present invention.
FIG. 2 is an enlarged view of a main part of FIG.
FIG. 3 is an enlarged view of a main part of a modified example.
FIG. 4 is an enlarged view of a main part of another modified example.
FIG. 5 is a partial cross-sectional view showing a use state of a conventional soft pipe joint.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylindrical body 2 Resin layer 5 Soft pipe 12 Outer peripheral surface of cylindrical body 13 End surface of cylindrical body 14 Engagement part 14a Projection 16 End inner peripheral surface of cylindrical body 22 End surface covering part 23 Inner peripheral surface covering part 24 Seal Part 25 Inner peripheral surface of inner peripheral surface covering portion 26 Protrusion 28 Boundary portion 28a Inner surface 28b of boundary portion Outer surface of boundary portion 51 Outer peripheral surface of soft tube

Claims (5)

An outer peripheral surface and an end surface of a metal tubular body are covered with a resin layer, and the tubular body is engaged with a tube wall of a soft pipe that is inserted into the tubular body and expanded in diameter. In a soft pipe joint provided with an engaging portion for preventing
A cylindrical inner periphery that extends from the end surface covering portion that covers the end surface of the cylindrical body to the end inner peripheral surface side of the cylindrical body and covers the inner peripheral surface of the cylindrical body. A surface covering portion is provided, and on the inner peripheral surface of the inner peripheral surface covering portion, a seal portion is formed in which the outer peripheral surface of the soft tube, which is inserted into the cylindrical body and expanded in diameter, is in close contact,
The inner peripheral surface covering portion has a thickness that is pressed by an end portion of the cylindrical body and a soft tube that is inserted into the cylindrical body and expanded in diameter,
On the inner peripheral surface of the cylindrical body, an annular recess is provided in the axially inner portion of the formation portion of the engagement portion,
A soft pipe joint, wherein an annular packing is held inside the recessed portion.   The soft pipe joint according to claim 1, wherein the seal portion includes a ring-shaped protrusion protruding from an inner peripheral surface of the inner peripheral surface covering portion.   The soft pipe joint according to claim 2, wherein the protrusion is formed in an inwardly-pointed shape.   2. The protrusion is a protrusion that protrudes inward from an inner peripheral surface of the cylindrical body and can be eaten into a tube wall of a soft pipe that is inserted into the cylindrical body and has an enlarged diameter. The soft pipe joint according to claim 3. The inner peripheral surface covering portion, the cylindrical body engaged with the end portion inner peripheral surface of the resin layer of claims 1 to 4 has a function of preventing from being separated from the tubular body A soft pipe joint described in any one of the above.

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