JP2009150503A - Pipe joint structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe joint structure capable of exerting high sealing performance and surely preventing leakage of fluid even when a connected pipe has a distorted shape and the pipe itself is hard to deform. <P>SOLUTION: The pipe joint structure 1 includes a body 2 formed with a connection opening 20 having a hole part 21 and a tapered surface 24 on an inner periphery, a first ferrule 3 which takes an almost cylindrical shape having at a front an inclined part 31 formed with a tapered surface 30 on an outer periphery and is formed with annular convexes 36 with a plurality of concaves 35, 35' provided in parallel, a second ferrule 4 which engages with a groove part 16 provided in an outer wall 17 of the connected pipe P, contacts with and supports the ferrule 3 from behind, and a fastening member 5 fastened to the connection opening 20 and pressing the second ferrule 4 from behind. The pipe joint structure is constructed so that the convexes 36 of the first ferrule 3 are closely contacted over the entire circumference of an outer wall part 17a of the connected pipe P in an air tight condition along with fastening of the fastening member 5 to the connection opening 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pipe joint structure.

  2. Description of the Related Art Conventionally, in the field of industrial machinery and the like, a pipe configuration including a connecting pipe has been used to transport a fluid such as liquid or gas. In the pipe configuration, a pipe joint structure for connecting the connecting pipe to another member is required. As such a pipe joint structure, a ferrule-type pipe joint structure is known (for example, Patent Document 1). .

JP 2007-146893 A

  In the ferrule-type pipe joint structure described above, one or two ferrules are interposed between the joint body and the nut member, and the joint body and the nut member are screwed together, whereby the ferrule and the joint body or connection are connected. This ensures sealing performance with the tube.

  Especially in cases where the pipe joint structure is used in the manufacturing process of semiconductors and solar cells, very dangerous fluids such as organic chemicals are handled. Since unusable defective products are discharged simply by changing the pressure and flow rate, a very high level of sealing performance is required.

  However, according to the conventional pipe joint structure including the one described in Patent Document 1, when the connecting pipe is made of metal such as stainless steel and the processing accuracy is extremely good, a certain sealing performance is obtained. Some of them could be used, but the connection tube is made of glass, for example, and the processing accuracy varies, so it is easy to form irregular shapes and the tube itself is difficult to deform. There is a problem that fluid leakage occurs.

  Therefore, the present invention has been made in view of the above problems, and even if the connecting pipe has an irregular shape and the pipe itself is not easily deformed, it exhibits high sealing performance and ensures fluid leakage. An object of the present invention is to provide a pipe joint structure that can be prevented.

  In order to solve the above-described problem, the pipe joint structure according to claim 1 includes a connection port having a hole part into which the connection pipe can be inserted and a tapered surface gradually expanding from the hole part on the inner periphery. The main body is formed into a substantially cylindrical shape with a tapered portion formed on the outer periphery and formed with a tapered surface penetrating the connecting pipe and capable of coming into contact with the tapered surface of the connecting port. A plurality of concave portions communicated in the circumferential direction in the circumference are provided in parallel along the axial direction, whereby a first ferrule in which an annular convex portion is formed between the concave portions, and an outer wall of the connecting pipe A second ferrule that engages with a groove provided on the connecting pipe and restricts relative movement in the axial direction with respect to the connecting pipe, and can abut and support the first ferrule from the rear, and the first ferrule and the second ferrule. And is fastened to the connection port with the second ferrule. A fastening member capable of pressing the tool from the rear, and the first ferrule via the second ferrule pressed against the fastening member when the fastening member is fastened to the connection port. Is pressed from behind and the tapered surface of the first ferrule is pressed against the tapered surface of the connection port so that the tapered surface of the first ferrule and the tapered surface of the connection port are brought into tight contact with each other. In addition, when the tapered surface of the first ferrule is pressed against the tapered surface of the connection port, the first ferrule is pressed by the radially inward pressing force acting on the inclined portion of the first ferrule. The convex part of the ferrule is deformed along the strained shape of the outer wall part of the connecting pipe to be contacted, and the convex part is made to adhere tightly to the entire circumference of the outer wall part of the connecting pipe. The gist.

  Further, in the pipe joint structure according to claim 2, in the configuration according to claim 1, a line of a shoulder portion that forms a rear end of the tapered surface of the first ferrule is formed on the concave portion of the first ferrule. The gist is that it is located within the arrangement range of the rearmost recess.

  According to a third aspect of the present invention, in the pipe joint structure according to the second aspect, the inner diameter dimension substantially corresponds to the outer diameter of the connecting pipe continuously to the edge portion on the front end side of the first ferrule. The gist is that the inner peripheral surface of the edge is formed.

  Further, the pipe joint structure according to claim 4 is a cross-sectional shape in which the convex portion of the first ferrule abuts on the outer wall of the connecting pipe in a line contact state in the configuration according to any one of claims 1 to 3. The summary is as follows.

  Further, the pipe joint structure according to claim 5 is characterized in that, in the configuration according to any of claims 1 to 4, the inclination angle of the tapered surface of the first ferrule is set to 25 to 35 degrees. To do.

  According to the present invention, a main body in which a connection port having a hole portion into which a connection pipe can be inserted, a tapered surface gradually expanding from the hole portion, and a connection port formed on the inner periphery, and the connection pipe is penetrated to connect the connection pipe. A substantially cylindrical shape having an inclined portion formed on the outer periphery with a tapered surface capable of contacting with the tapered surface of the mouth is formed in front, and a plurality of concave portions communicated in the circumferential direction are provided on the inner periphery of the inclined portion. By being recessed in parallel along the direction, the first ferrule in which an annular convex portion is formed between the concave portions and the groove portion provided on the outer wall of the connecting pipe are engaged with each other, While the relative movement in the axial direction is restricted, the second ferrule capable of abutting and supporting the first ferrule from the rear, and the first ferrule and the second ferrule are interposed and fastened to the connection port. A fastening member capable of pressing the second ferrule from behind. When the fastening member is fastened to the connection port, the first ferrule is pressed from the rear via the second ferrule pressed against the fastening member, and the tapered surface of the first ferrule By pressing the tapered surface of the connection port against the tapered surface, the tapered surface of the first ferrule and the tapered surface of the connection port are brought into tight contact with each other, and the tapered surface of the first ferrule is brought into contact with the connection port. When the pressing surface of the first ferrule is pressed against the inclined portion of the first ferrule, the convex portion of the first ferrule is brought into contact with the inclined portion of the first ferrule by the connecting pipe to be contacted. It is a pipe joint structure that is deformed along the strained shape of the outer wall part and tightly adheres the convex part to the entire circumference of the outer wall part of the connecting pipe, so that it exhibits high sealing performance, Leakage can be reliably prevented It made.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
1 is a partially cutaway side view showing the overall structure of the pipe joint structure according to the present embodiment, FIG. 2 is a partially exploded perspective view of the pipe joint structure according to the present embodiment, and FIG. 3 is a side sectional view of the first ferrule. 4 is an enlarged cross-sectional view showing a fastening state of the pipe joint structure according to the present embodiment, and FIG. 5 is an enlarged cross-sectional view showing a fastening completion state of the pipe joint structure according to the embodiment.
In the following description, the upper side in FIG. 1 is expressed as “front” and the lower side is expressed as “rear”.

As shown in FIG. 1, the pipe joint structure 1 according to this embodiment mainly includes a main body 2, a first ferrule 3, a second ferrule 4, and a nut 5 as a fastening member, and between the main body 2 and the nut 5. The connection pipe P is connected to the airtight state from the rear side of the main body 2 by the action of the first ferrule 3 and the second ferrule 4 interposed between the two.
In this embodiment, the pipe joint structure 1 is connected to a valve 7, and a valve body 9 that is movable by operating a handle 8 opens and closes a flow path 10 formed inside the main body 2, and branches from the connection pipe P to the branch pipe. The supply of fluid to P ′ can be controlled. The valve 7 and the branch pipe P ′ are fixed to the main body 2 with nuts 5 ′ and 5 ″, respectively.

The connecting pipe P is made of glass and manufactured with a design dimension (outer diameter) = 12 mm. However, as shown in FIG. 2, the actual dimensions are a = 12.077 mm, b = 11.535 mm, c = 11.681 mm, d = 12.038. A material having a complicated distortion in each direction such as mm is used.
As shown in FIG. 2, a groove 16 having a concave cross section is provided around the front end wall 15 of the connecting pipe P at an appropriate distance so that the second ferrule 4 can be engaged therewith. .

  Note that the connecting pipe P that is particularly targeted by the present invention is made of a material other than metal, has a variation in processing accuracy, and therefore tends to be distorted, and the pipe itself is also difficult to deform (relative to the ferrule). It is. A typical example of such a connecting pipe P is made of glass, but other than glass, for example, Teflon (registered trademark), polytetrafluoroethylene (PTFE) fluororesin, urethane resin, and the like are cylindrical and true. A material made of a material that is difficult to be formed into a circle and is easily distorted is suitable.

  As shown in FIG. 1, a connection port 20 is integrally formed in the main body 2. The connection port 20 has a substantially cylindrical shape whose inner diameter changes from the middle, communicates with a hole 21 into which the end wall 15 side of the connection pipe P can be inserted, and has a large diameter hole formed larger in diameter than the hole 21. A portion 22 is provided on the rear end side. The hole portion 21 and the large-diameter hole portion 22 are configured to be continuous by a tapered surface 24 that gradually increases in diameter toward the large-diameter hole portion 22. A male screw portion 26 for screwing the nut 5 is provided on the outer periphery of the connection port 20.

  As shown in FIG. 1, the first ferrule 3 and the second ferrule 4 are penetrated by the connecting pipe P and disposed at predetermined positions along the outer wall 17 of the connecting pipe P. As described above, each of them has a substantially cylindrical shape having an inner diameter dimension substantially corresponding to the outer diameter of the connecting pipe P, and has a generally symmetric configuration. That is, as shown in FIG. 2, in the first ferrule 3, an inclined portion 31 that is narrowed toward the front end and has a tapered surface 30 formed on the outer periphery is provided on the front half side, and the tapered surface 30 A body 33 having a constant thickness (about 2 mm in this embodiment) is provided on the rear half side by the continuous outer peripheral surface 32. On the other hand, in the second ferrule 4, an inclined portion 41 having a tapered shape toward the rear end and having a tapered surface 40 formed on the outer periphery is provided on the second half side, and the outer periphery continuous to the tapered surface 40. A body portion 43 having a certain thickness (about 2 mm in the present embodiment) by the surface 42 is provided on the front half side.

  On the other hand, in the first ferrule 3, as shown in FIG. 3, on the inner peripheral side of the inclined portion 31, the first concave portion 35 and the second concave portion 35 ′ that are communicated in the circumferential direction have a predetermined shape along the axial direction. Recessed in rows at intervals, an annular convex portion 36 is formed between the first concave portion 35 and the second concave portion 35 ′. An edge inner peripheral surface 38 is also formed on the inner periphery of the edge 31 ′ at the tip of the tapered surface 30, and each of the convex portion 36 and the edge inner peripheral surface 38 is chamfered to have a slightly rounded cross-sectional shape. ing.

The axial length W of the convex portion 36 and the protruding length D ₁ (D ₂ ) from the bottom surface of the first concave portion 35 (second concave portion 35 ′) are extremely small (in the present embodiment, about 0.5 to 0). .4 mm), and is set to about 1/2 to 1/3 of the axial length of the first recess 35, the second recess 35 ′, or the edge inner peripheral surface 38. It is preferable that the inner peripheral surface 3a of the trunk portion 33, the convex portion 36, and the edge inner peripheral surface 38 are formed flush from the viewpoint of workability by a lathe or the like.
Note that D ₁ <D ₂ or D ₁ > D ₂ can be set, but D ₁ = D ₂ is preferable. Thereby, when the connecting pipe P is tightened, it is possible to prevent a loss of pressing force due to the convex portion 36 falling to one side.

  Further, as shown in FIG. 2, the second ferrule 4 is provided with a protrusion 46 that protrudes in front of the body 43 and radially inward to form a stepped surface 45. The protruding portion 46 has a shape that is just fitted around the groove portion 16 of the connecting pipe P, and can regulate the relative movement of the second ferrule 4 in the axial direction with respect to the connecting pipe P.

The first ferrule 3 and the second ferrule 4 are used as a set, but a fitting portion 37 as shown in FIG. 3 is provided on the rear end side of the first ferrule 3, and the rear of the first ferrule 3 The end surface 37a and the stepped surface 45 of the second ferrule 4 are in contact with each other, and the outer half of the projection 46 of the second ferrule 4 (the portion protruding from the groove 16) is fitted to the fitting portion 37 of the first ferrule 3. It can be inserted.
As described above, the second ferrule 4 serves to abut and support the first ferrule 3 from the rear and to facilitate the positioning of the first ferrule 3.

  The nut 5 has, for example, a hexagonal shape in plan view, and as shown in FIG. 1, has a substantially U-shaped cross section opened to the front side, and has a through hole 50 through which the connecting pipe P passes. The inner wall of the nut 5 is formed in an annular shape corresponding to the outer peripheral shape of the connection port 20, and a female screw portion 52 that is screwed into the male screw portion 26 of the connection port 20 is provided.

  The connection port 20, the first ferrule 3, the second ferrule 4, and the nut 5 are all preferably made of resin, but the constituent materials are not limited. However, for the first ferrule 3, it is preferable to employ, for example, PFA (tetrafluoroethylene perfluoroalkyl vinyl ether copolymer) from the viewpoint of chemical resistance and predetermined mechanical strength. The tapered surface 24 portion of the connection port 20 is preferably more rigid than the tapered surface 30 portion of the first ferrule 3.

A method for using the pipe joint structure 1 constituted by each of the above-described constituent elements, operation, and the like will be described.
In the pipe joint structure 1, first, the first ferrule 3 and the second ferrule 4 are attached to the connection pipe P. This mounting is performed by fitting the second ferrule 4 so that the protrusion 46 is engaged with the groove portion 16 of the connecting pipe P, and then fitting the first ferrule 3 from the end wall 15 side of the connecting pipe P. Although the inner diameter of the protrusion 46 of the second ferrule 4 is smaller than the outer diameter of the connecting pipe P, the second ferrule 4 can be mounted by spreading the slit 48 provided as shown in FIG. It is what.

  Next, as shown in FIG. 4, the connecting pipe P on which the first ferrule 3 and the second ferrule 4 are mounted is inserted into the hole 21 in the connecting port 20 of the main body 2, and the connecting pipe P is connected to the first ferrule. First, insertion is performed until the tapered surface 30 of 3 and the tapered surface 24 of the connection port 20 contact each other. A constant gap is formed between the end wall 15 of the connecting pipe P and the bottom surface 21 ′ of the hole 21.

  Here, the inclination angle of the tapered surface 24 of the connection port 20 is shallower by about 3 to 5 degrees than the inclination angle of the tapered surface 30 of the inclined portion 31 of the first ferrule 3. As a result, when the fastening is completed, the tapered surface 24 of the connection port 20 and the tapered surface 30 of the first ferrule 3 can be brought into closer contact with each other, and a predetermined pressing force can be applied to the convex portion 36. It becomes easy to act. The inner peripheral surface 22 a of the large-diameter hole portion 22 of the connection port 20 is provided at a position where it slightly contacts the outer peripheral surface 32 of the body portion 33 of the first ferrule 3. The body 33 can be supported from the outside.

  Then, the nut 5 that has been positioned rearward as shown in FIG. 4 is moved forward so as to surround the first ferrule 3 and the second ferrule 4 as shown in FIG. 26 and the female threaded portion 52 of the nut 5 are screwed together using a tool such as a spanner. The nut 5 is provided with a tapered surface 54 having an inclined shape corresponding to the tapered surface 40 of the inclined portion 41 of the second ferrule 4. When the screwing is advanced, the taper of the inclined portion 41 of the second ferrule 4 is eventually reached. The surface 40 comes into contact with the tapered surface 54 of the nut 5 (see FIG. 5).

  When the screwing is further advanced, the taper surface 54 of the nut 5 presses the taper surface 40 of the inclined portion 41 of the second ferrule 4 and the first ferrule 3 is pressed from the rear via the second ferrule 4. The tapered surface 30 of the inclined portion 31 of the first ferrule 3 is pressed against the tapered surface 24 of the connection port 20. 5, the tapered surface 30 of the inclined portion 31 of the first ferrule 3 is deformed along the shape of the tapered surface 24 of the connection port 20, and the tapered surface 30 of the inclined portion 31 of the first ferrule 3 is obtained. And the tapered surface 24 of the connection port 20 are in close contact with each other in an airtight state. At this time, since the predetermined inner peripheral surface 38 is provided on the inclined portion 31 of the first ferrule 3, the vicinity of the edge portion 31 'of the tapered surface 30 can be particularly tightly sealed.

  In addition to the above, in the fastening completion state shown in FIG. 5, the convex portion 36 of the first ferrule 3 is deformed along the strained shape of the outer wall portion 17a of the connecting pipe P, and the convex portion 36 of the first ferrule 3 and the connecting pipe The outer wall portion 17a of P is in tight contact with the entire circumference. This is a predetermined configuration in which the convex portion 36 is disposed between the first concave portion 35 and the second concave portion 35 ′, so that the taper surface 30 of the inclined portion 31 of the first ferrule 3 is the taper of the connection port 20. When pressed against the surface 24, the radially inward pressing force acting on the inclined portion 31 of the first ferrule 3 acts on the convex portion 36 in a concentrated manner, and the convex portion 36 is connected to the connecting pipe P. This is probably because the outer wall portion 17a can be easily deformed along the strained shape.

  In order to effectively perform such deformation of the convex portion 36, as shown in FIG. 3, the line 39a of the shoulder portion 39 that forms the rear end of the tapered surface 30 of the first ferrule 3 has a rearmost first line 39a. It is good to constitute so that it may be located in arrangement range R of 2 crevice 35 '. More optimally, the line 39a of the shoulder 39 is substantially aligned with the rear end 35'a of the second recess 35 '. Further, it is preferable that the inclination angle (α in FIG. 3) of the tapered surface 30 of the first ferrule 3 is 25 to 35 degrees, more preferably about 30 degrees. Thus, it is possible to transmit the pressing force directed inward in the radial direction acting on the inclined portion 31 of the first ferrule 3 to the convex portion 36 without waste.

  In the pipe joint structure 1 of the present embodiment, the strain of the outer wall portion 17a of the connecting pipe P with which the convex portion 36 abuts is 5% at maximum (actual outer diameter = 11.4 mm to 12.6 mm in the present embodiment). To the extent that is acceptable.

As described above, according to the pipe joint structure 1 according to the present embodiment, the connecting pipe P has an irregular shape as shown in FIG. 2, and the pipe P itself is not easily deformed, but exhibits high sealing performance. As a result, fluid leakage can be reliably prevented. Accordingly, it is possible to prevent fluid leakage accidents in factories and transportation vehicles that use the pipe joint structure 1, and to reliably avoid contamination of impurities into the fluid and fluctuations in the fluid pressure and flow rate.
And even if the connecting pipe P is not good in processing accuracy, it is not necessary to discard or repeatedly perform a replacement test in order to find a fitting that exactly fits the connection port 20 or the first ferrule 3, It has a great effect on the reduction of the manufacturing cost and the improvement of productivity.

The description of the above embodiment does not limit the present invention, and various design changes and the like can be made without departing from the gist of the present invention.
For example, the convex part 36 of the 1st ferrule 3 can be made into various shapes, as shown to Fig.6 (a)-(d). Among them, a shape that can come into contact with the connecting pipe P in a line contact state (FIGS. 6A and 6B, etc.) is easy to concentrate stress, and an extremely high effect can be expected.
In the above, the configuration in which the convex portions 36 are arranged in one row is shown. However, as shown in FIG. 6 (e), a plurality of rows of convex portions 36, 36 ', ... (and corresponding concave portions 35, 35', 35 '). ', ...) can also be provided. However, since the stress is easily dispersed, it is considered that the one-row configuration can obtain a better result.
Further, the valve 7 is one example of application of the present invention, and the present invention may be applied to various other members for the purpose of direction change, merging, branching, closing, etc. The application to the valve (needle valve) as in the present embodiment is particularly optimal because the sealing performance can be secured even when an unexpected pressure is applied due to an erroneous operation or some trouble.

  The present invention provides a pipe joint structure that exhibits high sealing performance and can reliably prevent fluid leakage even when the connecting pipe has an irregular shape and the pipe itself is not easily deformed. Yes, it has industrial applicability.

1 is a partially cutaway side view showing an overall configuration of a pipe joint structure according to an embodiment. It is a partial exploded perspective view of the pipe joint structure concerning an embodiment. It is side surface sectional drawing of a 1st ferrule. It is an expanded sectional view showing the fastening situation of the pipe joint structure concerning an embodiment. It is an expanded sectional view showing the fastening completion state of the pipe joint structure concerning an embodiment. It is a fragmentary sectional view showing other embodiments of the 1st ferrule.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe joint structure 2 Main body 3 1st ferrule 4 2nd ferrule 5 Nut 16 Groove part 17 Outer wall 17a Outer wall part 20 Connection port 21 Hole part 24 Tapered surface 30 Tapered surface 31 Inclined part 31 'Edge 35 First recessed part 35' Second Concave part 36 Convex part 38 Edge inner peripheral surface 39 Shoulder part 39a Line 46 Protrusion part P Connection pipe
R Installation range α Inclination angle

Claims (5)

A main body in which a connection port having a hole part into which the connection pipe can be inserted, a tapered surface gradually expanding from the hole part, and having an inner periphery;
It forms a substantially cylindrical shape having a sloped portion formed on the outer periphery with a tapered surface penetrating through the connecting pipe and capable of coming into contact with the tapered surface of the connection port, and on the inner circumference of the sloped portion in the circumferential direction. The first ferrule in which an annular convex portion is formed between the concave portions by forming the plurality of concave portions communicated in parallel along the axial direction;
A second ferrule that engages with a groove provided on the outer wall of the connecting pipe to restrict axial relative movement with respect to the connecting pipe and that can abut and support the first ferrule from the rear;
A fastening member that is fastened to the connection port via the first ferrule and the second ferrule, and that can press the second ferrule from the rear,
With the fastening of the fastening member to the connection port,
The first ferrule is pressed from behind via the second ferrule pressed against the fastening member, and the tapered surface of the first ferrule is pressed against the tapered surface of the connection port, thereby the first ferrule. While closely contacting the tapered surface of the ferrule and the tapered surface of the connection port in an airtight state,
When the tapered surface of the first ferrule is pressed against the tapered surface of the connection port, the radially inward pressing force acting on the inclined portion of the first ferrule causes the first ferrule to A pipe joint structure in which the convex portion is deformed along the strained shape of the outer wall portion of the connecting pipe to be contacted, and the convex portion is brought into tight contact with the entire circumference of the outer wall portion of the connecting pipe. The shoulder line forming the rear end of the tapered surface of the first ferrule is located within the arrangement range of the rearmost concave portion of the concave portions of the first ferrule. Pipe joint structure. 3. The pipe joint structure according to claim 2, wherein an inner peripheral surface of an edge having an inner diameter dimension substantially corresponding to an outer diameter of the connection pipe is formed continuously to the edge on the front end side of the first ferrule. The pipe joint structure according to any one of claims 1 to 3, wherein the convex portion of the first ferrule has a cross-sectional shape in contact with the outer wall of the connection pipe in a line contact state. The pipe joint structure according to any one of claims 1 to 4, wherein an inclination angle of the tapered surface of the first ferrule is 25 to 35 degrees.

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