JP2020118299A - Coupling structure, pipe joint and method for forming coupling structure - Google Patents

Abstract

To provide a coupling structure that can couple a pipe member with a pipe joint firmly more than before without using welding.SOLUTION: A coupling structure couples an outer peripheral surface of a pipe member P with an inner peripheral surface 22 of a cylindrical member 20 to be fitted to the pipe member in an air-tight or liquid-tight manner, where an annular projection formed at the inner peripheral surface of the cylindrical member makes the pipe member and the cylindrical member impossible to be dismounted.SELECTED DRAWING: Figure 1

Description

The present invention relates to a connecting structure of a pipe member and a cylindrical member attached to the pipe member, and in particular, an outer peripheral surface of the pipe member and an inner peripheral surface of the cylindrical member have a sealing property and are non-separably connected. The present invention relates to a joint structure, a method for forming the joint structure, and a pipe joint having the joint structure.

As a joint structure of a piping member, there is a method of welding and connecting a pair of piping members as shown in Patent Document 1.

However, the connection of pipes by welding has various problems such as various preparatory work, bead removal after welding, and post-treatment including pickling of pipe lines, leading to a long lead time and an increase in cost. There is.

JP, 2007-247702, A

The present invention has been made in order to solve the above problems, and its main intended problem is to make it possible to connect a pipe member and a pipe joint more firmly than before without using welding. It is a thing.

FIG. 19 is a schematic diagram for explaining the principle of the present invention, and relates to the coupling structure of the outer peripheral surface of the pipe member P and the cylindrical member C mounted on this outer peripheral surface. Specifically, as shown in the upper diagram, an annular protrusion t is formed on the inner peripheral surface of the cylindrical member C, and the axial predetermined width d on the outer peripheral surface of the cylindrical member C is pressed inward in the radial direction. A pressing means Pr for operating is provided.
In the lower part of FIG. 19, the annular projection t is gradually bited into the outer peripheral surface of the tube member P by the radially inward force while moving the pressing means Pr to the right as shown by the broken line. Show.

That is, the coupling structure according to the present invention to which this principle is applied is a coupling structure that couples the outer peripheral surface of the pipe member and the inner peripheral surface of the cylindrical member mounted to the pipe member in an airtight or liquid-tight manner, It is characterized in that it has an annular projection formed on the inner peripheral surface of the cylindrical member and makes the tube member and the cylindrical member inseparable.

Since the annular protrusion is formed on the inner peripheral surface of the tubular member in this way, by making the annular protrusion bite into the outer peripheral surface of the pipe member, a stronger joint structure than ever can be obtained without using welding. Obtainable.

Further, the pipe joint according to the present invention is characterized in that the pipe joint is coupled to the pipe member, and constitutes the above-mentioned coupling structure together with the pipe member.
By using such a pipe joint, the above-described joint structure can be obtained, and the joint can be firmly joined to the pipe member without using welding.

As a concrete embodiment of the pipe joint, a first member in which a housing space for housing the pipe member is formed, an outer peripheral surface of the pipe member, and an inner peripheral surface of the first member forming the housing space ( Hereinafter, it is possible to cite an example including a cylindrical member that is interposed between the cylindrical member and a pressing surface and a pressing member that applies an axial force to the cylindrical member.

In order to cause the annular projection formed on the inner peripheral surface of the cylindrical member to bite into the outer peripheral surface of the tube member, an axial force by the pushing member causes a radially inward force to the cylindrical member. It is preferably configured.

Here, the configuration of FIG. 18 showing the main points as the pipe joint (the joint body as the first member, the cylindrical member, and the nut as the pushing member) will be examined.
When using this pipe joint, first, with the cylindrical member mounted on the pipe member, these are inserted into the joint body, and a nut that is a pushing member is screwed into the joint body from the rear side of the cylindrical member. Thereby, the cylindrical member can be pushed between the outer peripheral surface of the pipe member and the inner peripheral surface of the joint body.
Here, the inner peripheral surface of the joint body and the outer peripheral surface of the cylindrical member are inclined so that the diameter gradually decreases in the insertion direction of the pipe member, and a plurality of protrusions are provided on the inner peripheral surface of the cylindrical member. .. Accordingly, by pushing the cylindrical member toward the joint body, the cylindrical member is crushed inward in the radial direction, and the protrusion bites into the pipe member.

However, when the inner peripheral surface of the joint body and the outer peripheral surface of the cylindrical member are inclined, as shown in FIG. 18, when the force for pushing the cylindrical member is increased, the number of annular projections involved in the biting sharply increases. Therefore, the force that resists the pushing force also increases sharply. In other words, since the plurality of annular projections that bite into the pipe member simultaneously act as a resistance force, the pushing force becomes larger. Therefore, the tightening torque required for screwing the nut into the joint body increases, and unless the cylindrical member can be crushed until sufficient crimpability is obtained without sufficient tightening torque, the pipe member comes off from the pipe joint. ..

The above-mentioned problem is more remarkable as the diameter of the pipe member is larger, because the required tightening torque is larger.

Therefore, in order to solve the above-mentioned problems, it is preferable that the first member is formed with a force concentration portion that concentrates the radially inward force on a part of the outer peripheral surface of the cylindrical member. ..
With such a configuration, the radially inward force generated due to the axial force applied to the cylindrical member can be concentrated on a part of the outer peripheral surface of the cylindrical member. In addition to being able to reduce the resistance at the time of pushing, as shown in the schematic view of FIG. 19, the annular projections formed on the inner peripheral surface of the cylindrical member can be bited into the outer peripheral surface of the pipe member one by one, for example. ..
As a result, the force required to push in the cylindrical member (for example, the tightening torque when a nut is used) can be reduced, and thus the pipe joint according to the present invention can be applied to a large-diameter pipe member. Becomes

It is preferable that the force concentrating portion is a bulging surface that is a part of the housing surface and bulges radially inward.
In this case, the force can be concentrated on the outer peripheral surface of the cylindrical member with a simple structure.

In a cross section parallel to the axial direction of the cylindrical member, a plurality of the annular protrusions are provided along the axial direction, and the radially inward force generated in the cylindrical member causes the plurality of annular protrusions to follow the axial direction. It is preferable that each one bites into the outer peripheral surface of the pipe member.
With such a configuration, compared with a configuration in which a plurality of annular projections are bitten into the outer peripheral surface of the pipe member at a time, the force required to crush the cylindrical member becomes smaller, and it is necessary to push in the cylindrical member. The force can be further reduced.

Examples of the plurality of annular projections include a continuously formed spiral shape and a discontinuously formed annular shape.
With such a structure, it is possible to improve the crimpability between the pipe member and the pipe joint and the sealing property between them.

As an example of a specific configuration of the pressing member, a nut that is screwed into the first member, and a cylindrical element that receives a force in the axial direction from the nut to press the cylindrical member toward the first member. There is a configuration having.

Further, the method for forming a joint structure according to the present invention is a method for forming a joint structure for air-tightly or liquid-tightly joining an outer peripheral surface of a pipe member and an inner peripheral surface of a cylindrical member mounted on the pipe member. A first step of mounting a cylindrical member having an annular projection on an inner peripheral surface on a pipe member, a second step of pressing a predetermined axial width of the cylindrical member inward in a radial direction, and a pressing inward in the radial direction According to the third step, the annular protrusion formed in the axial direction predetermined width of the cylindrical member is bitten into the outer peripheral surface of the pipe member.
If the joint structure is formed in this way, the annular projection formed on the inner peripheral surface of the cylindrical member will bite into the outer peripheral surface of the pipe member, so that a stronger joint structure than ever can be obtained without using welding. You can

It is preferable to further include a fourth step of shifting the region of the cylindrical member pressed inward in the radial direction in the second step along the axial direction.
In this case, the annular projection formed on the inner peripheral surface of the cylindrical member can be gradually bited into the outer peripheral surface of the tube member, and the force required to push the cylindrical member can be reduced.

According to the present invention described above, the pipe member and the pipe joint can be joined more strongly than before without using welding, and further, by reducing the force necessary for pushing the cylindrical member, It can also be used to connect large-diameter pipe members.

FIG. 3 is an exploded cross-sectional view showing the configuration of the pipe joint in the embodiment of the present invention. The elements on larger scale of the inner peripheral surface of the cylindrical member in the same embodiment. Sectional drawing which shows the state before connection of a pipe joint and a pipe member in the same embodiment. The schematic diagram for demonstrating the function of the stress concentration part in the embodiment. The result of analyzing the force applied to the cylindrical member in the same embodiment (position immediately after the start of press-fitting into the cylindrical member). The result of analyzing the force applied to the cylindrical member in the same embodiment (the middle position of press-fitting into the cylindrical member). Sectional drawing which shows the state after connection of the pipe joint and the pipe member in the same embodiment. The photograph of the pipe member used for the experiment of the adhesiveness and sealability of the pipe joint in the same embodiment. Sectional drawing which shows the structure of the 1st member in other embodiment. Sectional drawing which shows the state after connection of the pipe joint and the pipe member in other embodiment. Sectional drawing which shows the structure of the cylindrical member in other embodiment. Sectional drawing which shows the state before connection of a pipe joint and a pipe member in other embodiment. Sectional drawing which shows the state after connection of the pipe joint and the pipe member in other embodiment. Sectional drawing which shows the structure of the pushing member in other embodiment. Sectional drawing which shows the structure of the annular protrusion in other embodiment. Sectional drawing which shows the structure of the annular protrusion in other embodiment. Sectional drawing which shows the structure of the annular protrusion in other embodiment. Sectional drawing which shows the structure of the joint main body in other embodiment. Sectional drawing which shows the coupling structure of the pipe member and cylindrical member in other embodiment. The schematic diagram explaining the usage method of the pipe joint in other embodiment. The schematic diagram explaining the force which acts on a cylindrical member when the conventional pipe joint is used. The schematic diagram explaining the force which acts on a cylindrical member when using the pipe joint of this invention.

An embodiment of the present invention will be described below with reference to the drawings.

In the pipe joint 100 of the present embodiment, a pipe member P is connected, and specifically, as shown in FIG. 1, a part of the pipe member P (here, a pipe end portion Pa) is inserted. It includes a joint body 10 as a first member having a mouth H, a cylindrical member 20 attached to the pipe end portion Pa, and a pushing member 30 that pushes the cylindrical member 20 toward the joint body 10 side. The pipe joint 100 here connects a pair of pipe members P whose pipe ends Pa are opposed to each other, and includes a cylindrical member 20 and a pushing member 30 used for each pipe member P. ing.
The configuration shown in FIG. 1 shows a state in which one (left) pipe member P is already connected to the pipe joint 100 and the other (right) pipe member P is not connected to the pipe joint 100. ..

The joint body 10 connects the pipe member P while allowing fluid to flow between the joint body 10 and the pipe member P, and as shown in FIG. 1, the pipe end portion inserted through the insertion port H. An accommodation space S that accommodates Pa is formed. The joint body 10 here connects a pair of pipe members P, and a pair of accommodation spaces S corresponding to the respective pipe end portions Pa of the respective pipe members P and a communication passage communicating these accommodation spaces S. L and L are formed.

More specifically, the joint body 10 has a substantially rotating body shape, and the diameter dimension of the portion 11 (hereinafter, also referred to as the accommodation surface 11) of the inner peripheral surface forming the accommodation space S is It is larger than the diameter dimension of the portion forming the communication passage L. A step is formed between the accommodation space S and the communication passage L, and the tube member P inserted into the accommodation space can be locked by the step.

As shown in FIG. 1, the cylindrical member 20 is interposed between the accommodation surface 11 and the outer peripheral surface of the pipe end portion Pa in a state where the pipe end portion Pa is accommodated in the accommodation space S described above, and these This is for ensuring the adhesion of the surfaces and the sealing property between them. The cylindrical member 20 here is designed to be press-fitted into an annular space formed between the accommodation surface 11 and the outer peripheral surface of the pipe end portion Pa, and specifically, in a state before press-fitting. The outer diameter (diameter of the outer peripheral surface 21) is slightly larger than the diameter of the accommodation surface 11, and the inner diameter (diameter of the inner peripheral surface 22) is slightly larger than the diameter of the pipe member P.

More specifically, the cylindrical member 20 has a substantially cylindrical shape, and includes a locking portion 23 that locks on the distal end surface of the inserted pipe end portion Pa, and an object to be pressed by a pressing member 30 described later. And a pressing surface 24. Then, the cylindrical surface 20 is inserted (press-fitted) into the accommodation space S together with the pipe member P by pressing the pressed surface 24 while the end face of the pipe member P is in contact with the locking portion 23. Is configured. The pressed surface 24 here is an inclined surface that is inclined with respect to the axial direction, but it does not necessarily have to be inclined.

Further, the cylindrical member 20 is provided with a taper portion 25 whose outer diameter gradually decreases toward the tip (on the side of the joint body 10). By making the outer diameter of the tip end side of the tapered portion 25 smaller than the diameter dimension of the accommodation surface 11 described above, the tip end portion of the cylindrical member 20 can be easily inserted into the accommodation space S. .. On the other hand, the outer peripheral surface 21 of the cylindrical member 20 on the rear side of the tapered portion 25 extends in the axial direction without inclining with respect to the axial direction.

Further, on the inner peripheral surface 22 of the cylindrical member 20, as shown in FIG. 2, an annular protrusion 26 is provided which protrudes radially inward. The annular projection 26 bites into the outer peripheral surface of the pipe end portion Pa when the cylindrical member 20 is press-fitted between the accommodation surface 11 and the outer peripheral surface of the pipe end portion Pa and is crushed in the radial direction. Although the protruding direction of the annular projection 26 is a direction slightly inclined from the radial direction toward the tip end side here, it is not limited to this and may be projected in the radial direction, for example. In this embodiment, a plurality of annular protrusions 26 are provided in the cross section along the axial direction, and these annular protrusions 26 are formed in a spiral shape as a whole. The annular projection 26 may be an annular one formed discontinuously in the cross section along the axial direction. The annular projection 26 is provided on the inner peripheral surface 22 of the cylindrical member 20 on the rear side of the tapered portion 25, and is not provided on the tapered portion 25.

As shown in FIG. 1, the pushing member 30 pushes the cylindrical member 20 toward the joint body 10, and has a pressing surface 31 that presses the pressed surface 24 of the cylindrical member 20. The pushing member 30 of the present embodiment is a nut into which the pipe member P is inserted and which is screwed into a threaded portion formed on the outer peripheral surface of the joint body 10. Although the pressing surface 31 is an inclined surface that is inclined with respect to the pressed surface 24 with respect to the axial direction, it does not necessarily have to be inclined.
As described above, the function of the pushing member 30 can be described as pushing the cylindrical member 20 relative to the joint body 10 if the cylindrical body 20 is focused, but if the coupling body 10 is focused, the joint body 10 is pressed. Can be described as retracting relative to the cylindrical member. That is, the pushing member 30 is for pulling the joint body 10 into the cylindrical member 20 while shortening the distance from the joint body 10 and pushing the cylindrical member 20 into the joint body 10 while shortening the distance to the joint body 10. is there. "Pushing" in this specification is a concept including both the above-mentioned functions (pushing in and pulling in).

Here, a method of connecting the pipe member P to the pipe joint 100 of the present embodiment will be described.

First, as shown in FIG. 3, a nut, which is the pushing member 30, is passed through the pipe member P (the pipe member P on the right side in FIG. 3) to be connected to the pipe joint 100, and the cylindrical member 20 is attached to the pipe end portion Pa (external fitting). In this state, the pipe end portion Pa is pressed against the joint body 10 so that the tip end portion of the cylindrical member 20 (specifically, the tapered portion 25) is pressed against the insertion port H of the joint body 10.

In this state, the nut serving as the pushing member 30 is screwed into the joint body 10. As a result, the pressing surface 31 of the pressing member 30 presses the pressed surface 24 of the cylindrical member 20, and an axial force is applied from the pressing member 30 to the cylindrical member 20, so that the cylindrical member 20 moves to the outer periphery of the pipe end portion Pa. It is pressed into the accommodation space S together with the pipe end portion Pa while being crushed between the surface and the accommodation surface 11.

However, the pipe joint 100 of the present embodiment converts the axial force applied to the cylindrical member 20 into a radially inward force as shown in FIGS. The inward force is concentrated on a part of the outer peripheral surface 21 of the cylindrical member 20.

More specifically, as shown in FIG. 4A in particular, on the receiving surface 11 of the joint body 10, the axial force applied to the cylindrical member 20 is converted into a radially inward force, and the diameter thereof is changed. A force concentrating portion X for concentrating the inward force in a part of the outer peripheral surface 21 of the cylindrical member 20 is provided. In FIG. 4a, it seems as if the housing surface 11 of the joint body 10 does not move and the cylindrical member 20 is pushed into the housing surface 11, but in reality, as described above, The main body 10 is also pulled into the cylindrical member 20.

4b and 4c show the results of FEM analysis of the force applied to the outer peripheral surface 21 of the cylindrical member 20 in this configuration. From this analysis result, it is understood that the force is concentrated on the part of the outer peripheral surface 21 of the cylindrical member 20 by the force concentrating portion X. The length of the arrow in FIGS. 4b and 4c indicates the magnitude of the force applied to the outer peripheral surface of the cylindrical member 20. The longest arrow in the illustrated example corresponds to 700 MPa.

The force concentrating portion X is, for example, a bulging surface that bulges radially inward from the accommodation surface 11, and is a surface that receives the tip portion (taper portion 25) of the cylindrical member 20 in the state of FIG. 3. The force concentrating portion X here is provided in the vicinity of the insertion port H in the accommodation surface 11, and the portion of the accommodation surface 11 where the force concentrating portion X is not provided is inclined with respect to the axial direction. Without, it extends along the axial direction.

When the axial force applied to the cylindrical member 20 is converted into a radially inward force by the force concentrating portion X and concentrated on a part of the outer peripheral surface 21 of the cylindrical member 20, as shown in FIG. The cylindrical member 20 is crushed and deformed at the location where the force is concentrated, and the annular projection 26 formed on the inner peripheral surface 22 of the cylindrical member 20 bites into the outer peripheral surface of the pipe member P.

As shown in FIGS. 4a, 4b, and 4c, the force concentrating portion X of the present embodiment concentrates the radially inward force on a part of the outer peripheral surface 21 of the cylindrical member 20 to thereby cause the cylindrical member 20 to move. The plurality of annular projections 26 formed on the inner peripheral surface 22 of the above are configured to gradually (for example, one by one) bite into the outer peripheral surface of the pipe member P along the axial direction.

In this way, the cylindrical member 20 is pushed toward the joint body 10 to the state shown in FIG. 5 while the nut, which is the pushing member 30, is screwed onto the joint body 10, so that the cylindrical member 20 moves to the accommodation surface 11 and the pipe end. The annular projection 26 formed on the inner peripheral surface 22 of the cylindrical member 20 bites into the outer peripheral surface of the pipe end portion Pa while being pressed into the annular space formed between the outer peripheral surface of the pipe member P and the outer peripheral surface of the pipe member P. And the pipe joint 100 are firmly coupled and connected. As a result, the connecting structure is formed by using the annular projection 26 formed on the inner peripheral surface 22 of the cylindrical member 20 between the outer peripheral surface of the pipe end portion Pa and the inner peripheral surface 22 of the cylindrical member 20. A coupling structure that has a sealing property (airtightness or liquid-tightness) and cannot be separated is formed.

With the pipe joint 100 configured in this manner, force concentration is performed so that the annular protrusions 26 formed on the inner peripheral surface 22 of the cylindrical member 20 bite into the outer peripheral surface of the pipe member P one by one along the axial direction. Since the portion X is provided, the force required to push the cylindrical member 20 (tightening torque of the nut that is the pushing member 30) can be reduced as compared with the configuration in which the plurality of annular protrusions 26 are bitten all at once. For example, it is possible to apply to a pipe member P having a large outer diameter of about 30 mm.

Further, the cylindrical member 20 is press-fitted into the annular space formed between the accommodation surface 11 and the outer peripheral surface of the tube end portion Pa, and the annular protrusion 26 formed on the inner peripheral surface 22 of the cylindrical member 20 is attached to the tube end. Since it digs into the outer peripheral surface of the portion Pa, very good adhesion and sealability can be obtained between the accommodation surface 11 and the outer peripheral surface of the pipe member P.
The photograph shown in FIG. 6 is the proof of that, and it is the result of keeping the pipe member P connected to the pipe joint 100 of this embodiment in a sealed state and continuously supplying pressure oil. That is, when the pipe member P is hermetically closed and the pressure oil is continuously supplied, if the adhesion between the accommodation surface 11 and the outer peripheral surface of the pipe member P is insufficient, the pipe joint 100 may cause the pipe member P to move. Although the pressure oil continues to leak if it comes off and the sealing property is insufficient, the pipe member P actually ruptured (the portion surrounded by the broken line in the photograph). This is proof that extremely high adhesion and sealing properties are obtained between the accommodation surface 11 and the outer peripheral surface of the pipe member P. The pipe member P used here is made of carbon steel having an outer diameter of 34 mm and a wall thickness of 6.4 mm, and has a tensile strength of 500 N/mm ² . The breaking pressure was 230 MPa.

Further, as shown in FIG. 4c, the portion other than the force concentrating portion X on the accommodation surface 11 and the outer peripheral surface 21 on the rear side of the tapered portion 25 of the cylindrical member 20 do not incline with respect to the axial direction, and Since it extends along the direction, the radially inward force does not act on the cylindrical member 20 in the portion of the cylindrical member 20 after passing through the force concentrating portion X, and the deformation of the cylindrical member 20 is suppressed, The pushing of the cylindrical member 20 is not hindered. As a result, the force required to push the cylindrical member 20 in can be further reduced.

Moreover, since the annular projection 26 formed on the inner peripheral surface 22 of the cylindrical member 20 has a spiral shape as a whole, the sealing performance is further improved by making the annular projection 26 bite into the outer peripheral surface of the pipe member P. You can

The present invention is not limited to the above embodiment.

For example, as shown in FIG. 7, the first member 40 into which the pipe end portion Pa is inserted may be a member different from the joint body 10. Specifically, the first member 40 has a storage space S in which the pipe end portion Pa is stored, as in the above embodiment, and the storage surface 41 and the pipe end portion Pa that form the storage space S are formed. The cylindrical member 20 is press-fitted between itself and the outer peripheral surface. The communication passage L communicating with the accommodation space S is formed here between the first member 40 and the joint body 10.

Then, in the pipe joint 100 here, as shown in FIG. 8, the end surface 12 of the joint main body 10 and the end surface 42 of the first member 40 face each other, and these end surfaces 12, 42 are seals such as O-rings. It is configured to be in close contact with the member Z. Specifically, similarly to the above-described embodiment, the pushing member 30 pushes the cylindrical member 20 toward the first member 40, so that the first member 40 is pushed toward the joint body 10. As a result, the end surface 12 of the joint body 10 and the end surface 42 of the first member 40 come into close contact with each other via the seal member Z such as an O-ring.

With such a configuration, since the first member 40 is a member separate from the joint body 10, the first member 40 can be separated from the joint body 10 by removing the nut that is the pushing member 30 from the joint body 10. Is possible. In other words, the joint body 10 can be moved in the radial direction, the pipe joint 100 that can be attached to and detached from the pipe member P can be provided, and workability in, for example, a narrow space can be improved.

The pushing member 30 may be the one shown in FIGS. 9 to 11.
Specifically, in addition to the nut 30a in the above embodiment, the pushing member 30 further includes a cylindrical moving body 30b that receives a force in the axial direction from the nut 30a and presses the cylindrical member 20 toward the joint body 10. ..
The cylindrical moving body 30b has an inner diameter smaller than the outer diameter of the cylindrical member 20, and a step portion 32 is formed on the inner peripheral surface thereof to project inward in the radial direction and receive the end portion of the cylindrical member 20. There is.

When this pipe joint 100 is used, as shown in FIG. 10, the nut 30a is first passed through the pipe member P, and then the cylindrical moving body 30b is mounted. Then, the cylindrical member 20 is attached to the pipe member P. In that state, the pipe member P is inserted into the accommodation space S. Then, the cylindrical moving body 30b is pushed toward the joint body 10 by the nut 30a, so that the cylindrical moving body 30b forms the cylindrical member 20 disposed on the outer peripheral surface of the pipe end portion Pa and the housing surface 11 of the joint body 10. Is pressed in between.

With such a configuration, when the cylindrical moving body 30b is pushed by the pushing member 30, the axial position of the pipe member P is not restricted. Further, as shown in FIG. 11, when the inner diameter of the left pipe member is larger than the outer diameter of the right pipe member, the axial mounting position of the right pipe member is not restricted at all, so-called double pipe structure. Is composed of.

The pushing member 30 is not limited to the nut of the above-described embodiment, and as shown in FIG. 12, a flange portion F provided at the pipe end portion Pa of each of the pair of pipe members P, a screw connecting the flange portion F, and the like. It may be configured with the connecting portion B of.
Specifically, the cylindrical member 20 is fitted onto each of the pair of pipe members P, and the respective pipe ends Pa are inserted into the accommodation space S. In this state, the cylindrical member 20 can be pushed in while reducing the distance between the flange portions F by inserting and tightening the connecting portions B such as screws into the plurality of screw holes formed in the respective flange portions F.
In addition, the 1st member 10 in the structure of FIG. 12 is the joint main body of the said embodiment, the 1st element 10a in which one accommodation space S was formed, and the 2nd element 10b in which the other accommodation space S was formed. The opposing surfaces of the first element 10a and the second element 10b are in close contact with each other via a seal member Z such as an O-ring.

The force concentrating portion X may be provided at a plurality of locations on the accommodation surface 11 as shown in FIG. 13a.
Further, as shown in FIG. 13b, the force concentrating portion X may be provided not only in the vicinity of the insertion port H on the accommodation surface 11 but also at a position separated from the insertion port H to the communication path L side.

Although a plurality of annular protrusions 26 are provided on the inner peripheral surface 22 of the cylindrical member 20 of the above-described embodiment, as shown in FIG. 14, one annular protrusion 26 is provided on the inner peripheral surface 22 of the cylindrical member 20. It may be.

The pipe joint 100 of the above-described embodiment is for connecting a pair of pipe members P whose pipe ends Pa are opposed to each other, but as shown in FIG. 15, the connecting space is L-shaped. Alternatively, the pair of pipe members P may be connected in a state where the pipe ends Pa are oriented orthogonally to each other.
Further, the pipe joint 100 of the above-described embodiment connects the pair of pipe members P, but one side may not be the pipe member, and, for example, connects a port of a fluid device or the like to the pipe member P. The pipe joint 100 may be used for this purpose.

Further, as shown in FIG. 16, the pipe joint 100 only needs to be configured by using at least the cylindrical member 20, and the joint body 10 and the pushing member 30 in the above embodiment are not necessarily required.

Moreover, as shown in FIG. 17, if the annular projection 26 formed on the inner peripheral surface 22 of the cylindrical member 20 is previously bitten into the outer peripheral surface of the pipe member P, the pushing member 30 will be used as the pipe joint 100. It does not have to be provided.

More specifically, as shown in FIG. 17, firstly, the pipe member P fitted with the cylindrical member 20 is fixed to the stopper 50. At this time, the pipe end portion Pa and the cylindrical member 20 are accommodated in the accommodation space S1 of the joint body corresponding member 60 corresponding to the joint body 10. In this state, the pushing member 30 prepared separately from the pipe joint 100 is pushed into the annular space between the outer peripheral surface 21 of the cylindrical member 20 and the housing surface 61 forming the housing space S1 by, for example, the hydraulic cylinder 70. Also in this case, the axial force applied to the cylindrical member 20 by the hydraulic cylinder 70 is converted into the radially inward force by the force concentrating portion X provided on the inner peripheral surface of the pushing member 30, and the cylindrical member 20. Concentrate on the outer peripheral surface 21 of the. As a result, the annular protrusion 26 bites into the outer peripheral surface of the pipe member P.
In this way, if the annular projection 26 is made to bite into the outer peripheral surface of the pipe member P in advance, the pipe member P can be inserted into the accommodation space S of the joint body 10, and therefore the nut can be screwed into the joint body 10. The tightening torque required for joining can be made very small.
In the example shown in FIG. 17, the pushing member 30 is axially pushed (press-fitted) into the accommodation space S1 and then separated from the tip end of the cylinder 70, so that the pushing member 30 is fixed integrally with the joint body equivalent member 60. Indicates that Further, reference numeral 60a is a screw portion for coupling. In this case, the member 60 corresponding to the joint body of the accommodation space S1 may be omitted. It is also possible to pull out the pushing member 30 while fixing it to the tip of the cylinder. When the push-in member 30 is pulled out, the pull-out resistance can be reduced, for example, by radially expanding the push-in member 30 by hydraulic pressure.

In FIGS. 1 to 17 described above, an example in which a press-fitting operation is mainly adopted as the pressing means Pr (see FIG. 19) for pressing the cylindrical member inward in the radial direction is shown. The operation method is not limited. That is, as described above, the press-fitting operation system simultaneously generates a pressing force inward in the radial direction with the movement of the pressing member such as the nut along the axial direction. In addition, the generation of the pressing force inward in the radial direction and the axial movement of the pressing means Pr may be performed at different timings. Examples of such a method include a method using a known rolling roller (for example, Japanese Patent Laid-Open No. 11-290980) and a caulking method in which a split mold is used to reduce the diameter in the radial direction.

Besides, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

100... Pipe joint P... Pipe member Pa... Pipe end portion 10... Joint body (first member)
H... Insert S S... Storage space L... Communication passage 11... Storage surface 20... Cylindrical member 21... Outer peripheral surface 22... Inner peripheral surface 23... Stopper surface 24... Pressed surface 25... Tapered portion 26... Annular projection 30... Pushing member 31... Pressing surface X... Force concentrating portion

Claims (11)

A coupling structure for air-tightly or liquid-tightly coupling an outer peripheral surface of a pipe member and an inner peripheral surface of a cylindrical member mounted on the pipe member,
A coupling structure having an annular projection formed on the inner peripheral surface of the cylindrical member, and making the tube member and the cylindrical member inseparable. A pipe joint coupled to the pipe member,
A pipe joint that constitutes the joint structure according to claim 1 together with the pipe member. A first member in which a housing space for housing the pipe member is formed;
The cylindrical member interposed between the outer peripheral surface of the pipe member and the inner peripheral surface of the first member that forms the accommodation space (hereinafter referred to as the accommodation surface);
The pipe joint according to claim 2, further comprising a pushing member that applies an axial force to the cylindrical member. The pipe joint according to claim 3, wherein the axial force of the pushing member is configured to generate a radially inward force on the cylindrical member. The pipe joint according to claim 4, wherein the first member is formed with a force concentration portion that concentrates the radially inward force on a part of an outer peripheral surface of the cylindrical member. The pipe joint according to claim 5, wherein the force concentration portion is a bulging surface that is a part of the housing surface and bulges radially inward. In a cross section parallel to the axial direction of the cylindrical member, a plurality of the annular protrusions are provided along the axial direction,
The radial inward force generated on the cylindrical member is configured to bite into the outer peripheral surface of the tube member one by one along the axial direction by the plurality of annular projections. The pipe joint according to item 1. The pipe joint according to claim 7, wherein the plurality of annular protrusions are continuously formed in a spiral shape or discontinuously formed in an annular shape. The pushing member is
A nut screwed to the first member,
The pipe joint according to any one of claims 3 to 8, further comprising a cylindrical element that receives an axial force from the nut to press the cylindrical member toward the first member. A method for forming a joint structure for air-tightly or liquid-tightly joining an outer peripheral surface of a pipe member and an inner peripheral surface of a cylindrical member mounted on the pipe member,
A first step of mounting a cylindrical member having an annular protrusion on an inner peripheral surface thereof on a pipe member;
A second step of pressing a predetermined axial width of the cylindrical member inward in the radial direction;
A third step of causing the annular projection formed in the axial direction predetermined width of the cylindrical member to bite into the outer peripheral surface of the tube member by the inward pressing in the radial direction. The method for forming a joint structure further comprising a fourth step of axially shifting an area of the cylindrical member pressed inward in the second step in the axial direction.