JPH09257171A - Tube connecting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide structure for preventing the generation of a chemical solution leak or storage while chemical resistance is enhanced in tube connecting structure for connecting a flexible tube and a functional member such as over valve. SOLUTION: A joint 1 has a joint main body 11 and a fastening cap 12, an inner cylinder 14 for accepting a flexible tube 2 in an outer fitting sate and an outer cylinder 15 for fitting outside the fastening cap 12 are arranged on the connecting side of the joint main body 11, the space formed by these is used as a tube end accepting part 16, and a seal promotion rib 14a is circumferentially formed in the outer circumference on the open side of the inner cylinder 14. A taper guide surface 15a narrowed inward is formed on the open edge side of the outer cylinder 15, the fastening cap 12 has a fastening inner flange 19 on the tube insertion side, and a seal sleeve 13 having flexibility separated from the joint 1 and the flexible tube 2 is formed in an outer fitting state in the outer circumference on the flexible tube 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube connecting structure for connecting a flexible tube to another functional member such as a valve.

[0002]

BACKGROUND OF THE INVENTION For example, in a manufacturing plant in the field of fine chemicals or in the field of manufacturing semiconductor parts, it is premised that chemical resistance is high, and various bacteria and impurities are mixed in and chemicals leak out. Inconveniences such as these must be eliminated extremely strictly, and such measures are always required. For example, even piping (tubing) is configured to meet the request, but in this kind of piping, the above-mentioned inconvenience often occurs at the connecting portion, and the sealing performance of this portion is Improvement is always sought.

At present, fluorocarbon resin is most suitable as a material which meets the requirement of chemical resistance, but this resin is inferior in mechanical strength, elasticity and toughness, and is used as a structural material, especially for grasping objects. Since it is a difficult material when used for the purpose, it is difficult to configure the joint part when it is used as piping equipment, and as a result, connection failure at this part, leakage of chemical liquid, or chemical liquid remaining in the previous process Accumulation occurred and attempts were made to improve it.

To explain such a conventional attempt, first, in the structure shown in FIGS. 7A and 7B, the outer sleeve Sa is provided between the joint body 11 'and the tightening nut 12' in the joint 1 '. An inclined surface is provided between the outer sleeve Sa or the joint body 11 'and the tightening nut 12', and the flexible tube 2 is attached to the inner cylinder of the joint body 11 'by tightening the tightening nut 12'. It is intended to be fixed by pressing it against 14 'in a hook shape.
However, in such a system, the flexible tube 2 itself is still in a straight shape, and if it is made of a fluororesin material in consideration of chemical resistance, the joint 1'of the flexible tube 2 is used. There is a risk that it may come off and liquid leakage may occur, so it cannot be applied when a higher degree of tightness is required.

From the above, FIG. 7 (c) (d)
A part of the joint body 11 'is inserted from the inside so as to bulge outward at the tube end of the flexible tube 2 connected as shown in FIG. 7 (see FIG. 7C), or the inner sleeve Sb of another member is inserted. Insertion method (Fig. 7 (d))
(See) has been taken. However, in such cases,
In the case shown in FIG. 7 (c), the inner cylinder 14 'is projected from the joint body 11', so that a long tightening nut length is required, and the length of the main body in the joint 1'part becomes long, We cannot meet the demand for miniaturization. In addition, according to this method, by tightening the tightening nut 12 ', the flexible tube 2 is fastened between the tightening nut 12' and the inner cylinder 14 '. Since there is no action of pressing the inner cylinder 14 'into the inner cylinder 14', this cannot be said to be a sufficient countermeasure against liquid leakage.

Further, in the structure shown in FIG. 7D, since the inner sleeve Sb is fitted, the inner sleeve Sb having a diameter considerably larger than the inner diameter of the flexible tube 2 must be applied. The mounting work is extremely difficult to perform. Even in such a case, for example, the tightening nut 12 'may be loosened due to vibration caused by water hammer, pulsation, etc. due to the liquid itself being sent to the inside, vibration of the external device, or even thermal stress. Nut 1 by pulling or pulling
If the pressing by 2'is loose, liquid leakage may occur. Furthermore, it is practically impossible to prevent the portion indicated by P ₁ in the drawing from occurring in this case, and a liquid pool in which the chemical liquid etc. flowed in the previous step remains is generated there, and the chemical solution in the subsequent processing step is There was also a problem of causing quality changes.

Further improvement is attempted from the progress of such technical development, and a conventional type shown in FIG. 6 is close to the present invention. The joint 1'includes a joint body 11 'and a tightening nut 12', and a resin tube assembled therein has an inner sleeve 2 when assembled.
0'is press-fitted inside the end portion of the flexible tube 2 so that the end portion of the flexible tube 2 is partially bulged outward, and this portion is formed by the tightening nut 12 ' It pushes to the side. When such a tightening structure is adopted, the sealing function is exerted at each of the portions indicated by P _{1 to} P ₄ in the figure, but in reality, sufficient sealing performance is not always obtained for the following reasons. It wasn't working.

That is, when such a tightening structure is adopted, as the tightening of the tightening nut 12 'is advanced, the main body joining surface formed as an outwardly spread tapered surface on the inner side of the inner sleeve 20'. 22 'is the joint body 11'
Inner cylindrical joint surface 11a of the 'come into contact, during the site That figure is the first seal at the site indicated by P _1, further periphery and tightening the nut 12 the tube' taper formed on the outer tube 15 'in Sealing is achieved at a portion P which is a contact portion with the guide surface 15a ', and further, the inner sleeve 2 is provided.
Sealing is performed at the portion P ₄ between the outer peripheral rib 21 ′ at 0 ′ and the inner surface of the flexible tube 2. The dimensional relationship between the inner sleeve 20 ′ and the joint body 11 ′, and further, Due to the difference in the thickness of the flexible tube 2 and the like, the sealed state cannot be obtained uniformly at all of P ₁ , P ₂ , and P ₄ , and some of them loosen.

Further longitudinal case dimension longer slack occurs at the site of P ₂ is in, Although seal is being at the site of P ₁ in such a case at the same time, the joint body in this portion of the inner sleeve 20 ' The processing accuracy of 11 'cannot always be obtained sufficiently, and due to the difference in the pressing angle, it is not always possible to obtain satisfactory secrecy at the portion of P ₁ . Due to this, the conventional method does not always obtain a perfect sealed state, and the leakage of the chemical solution at that site and the partial residual of the chemical solution supplied in the previous process occur. However, the above-mentioned purpose was not always achieved.

[0010]

The present invention has been made in view of such a background, and it is a technical object to develop an improved tube connection structure excellent in sealing property. Is.

[0011]

That is, the tube connecting structure according to claim 1 is a structure in which a flexible tube is connected to another functional member through a joint, wherein the joint includes a joint body and a tightening cap. With
In addition, an inner cylinder for receiving the flexible tube in an externally fitted state and an outer cylinder for externally fitting the tightening cap are provided on the connection side of the joint body, and the space formed by these is used as a tube end receiving portion. Further, the inner cylinder is provided with a seal-promoting rib in a circumferential shape on the outer peripheral portion on the open side thereof, and further, an inner conical taper guide surface is formed on the open end side of the outer cylinder, The attached cap has an inner flange for tightening on the tube insertion side, and further has a joint and a flexible seal sleeve separate from the flexible tube on the outer periphery of the flexible tube in an externally fitted state. In a state where the flexible tube is externally fitted to the inner cylinder, a seal sleeve is externally fitted to the flexible tube at that portion,
The seal sleeve is deformed by tightening the tightening cap in this state, and the deformed seal sleeve is used to assemble the flexible tube to the inner cylinder in a pressed state. According to the present invention, the flexible tube and the joint are separated from each other by the seal sleeve, which is pressed by the tightening cap and deforms while pressing the flexible tube against the inner sleeve and the seal sleeve between the flexible tube and the outer cylinder. Will be blocked, and a reliable sealing action will be exhibited.

In addition to the above requirements, the tube connection structure according to a second aspect of the present invention is characterized in that the inner cylinder is formed integrally with the joint body. According to this invention, since the inner cylinder is formed integrally with the joint body, the end portion of the flexible tube is formed into a bag shape, and the tube end receiving portion is completely cut off from the passage of the chemical liquid or the like. Is constituted, and the remaining of the chemical solution is completely prevented.

The tube connecting structure according to claim 3 is characterized in that, in addition to the requirements of claim 1, the inner cylinder is formed separately from the joint body. According to the present invention, since the inner cylinder is separate from the joint body, the degree of freedom in design is further increased.

Further, in addition to the above requirements, the tube connection structure according to claim 4 is characterized in that the insertion side end of the inner cylinder is tapered in a tapered shape. Is. According to the present invention, the tapered portion of the inner cylinder facilitates fitting of the flexible tube.

Further, in addition to the above requirements, in the tube connecting structure according to a fifth aspect of the invention, the tightening cap is a tightening nut screwed into the joint body, and the hand tightening portion and the wrench hook portion are provided on the outer peripheral portion. It is characterized by being formed. According to the present invention, since the tightening cap is configured as a cap-shaped nut and has the hand tightening portion and the wrench hook portion, the tightening work can be easily performed.

Furthermore, in addition to the above requirements, the tube connection structure according to a sixth aspect of the present invention is characterized in that the joint is made of a fluororesin. According to the present invention, since the fluorine-based resin having high chemical resistance is used, it is possible to obtain a configuration suitable as a member for piping such as a special chemical liquid.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be specifically described based on the illustrated embodiments. 1 and 2 are side views showing a usage mode of the present invention, showing a state in which a flexible tube 2 is connected by a joint 1 to a valve V which is one of functional members, for example. Is. The connection structure will be described below. First, the joint 1 includes a joint body 11 and a tightening cap 12, and further includes a separate seal sleeve 13. These materials are appropriately selected according to the purpose, but a fluororesin is a preferable example. First, the joint body 11 has an inner cylinder 14 inside which the flexible tube 2 is assembled in an externally fitted state, and an outer cylinder 15 is formed so as to cover the outer side thereof. As a result, the hollow space of the tube end receiving portion 16 is formed so as to be sandwiched between the inner cylinder 14 and the outer cylinder 15. A functional member connecting portion 17 is formed on the opposite side of the joint body 11.

First, the inner cylinder of the joint body 11 is
The flexible tube 2 has a seal promoting rib 14a on the open end side, and as a result, the flexible tube 2 externally fitted has a shape that bulges outward in a circumferential shape at the tube end. The outer peripheral surface of the seal promoting rib 14a is a tapered surface 14b, and is configured to improve the sealing action at the time of sealing the flexible tube 2 and the workability at the time of fitting. On the other hand, the outer cylinder 15 has a taper guide surface 15a on the open end side, and a male screw 15b for screwing the tightening cap 12 on the outer peripheral side thereof.

Next, the tightening cap 12 that is screwed into the joint body 11 will be described. This is one in which the female screw ring portion 18 and the tightening inner flange 19 are integrally formed. A female screw 18a is formed on the inner peripheral surface of the female screw ring portion 18 and is screwed with the male screw 15b of the outer cylinder 15. Also, this female threading portion 18
An uneven strip is formed on the outer circumference of the
b. On the other hand, the tightening inner flange 19 has a tube insertion hole 19a opened at the center thereof and a wrench hook 19b such as a spanner formed on the outer peripheral side thereof. When the joint 1 is made of a fluororesin, due to the softness of the material, the hand tightening portion 18b is normally gripped and tightened, and the wrench hooking portion 19b is used to further tighten the spanner. Tighten with a tool such as.

Next, the joint body 11 and the tightening cap 1
2, the seal sleeve 13 which is configured separately from the flexible tube 2 will be described. In a free state, this is a short cylindrical member whose inner peripheral surface is substantially smooth, and the inner taper 1 having an inner recess is formed on the inner side thereof.
3a is formed, and on the opposite side, a tightening side inner taper 13b is provided which projects inward.

The basic embodiment of the present invention has the structure as described above, and the flexible tube 2 is connected as follows. As shown in FIG. 3A, the tightening cap 12 and the seal sleeve 13 are first externally fitted to the flexible tube 2 in advance. In this state, FIG.
Connect the flexible tube 2 to the joint body 1 as shown in (b).
1 so that the inner cylinder 14 in FIG.
As shown in FIG. 3 (c), the end is fitted until it comes into contact with the innermost part of the tube end receiving portion 16. In this work, the tapered surface 14b of the inner cylinder 14 assists the insertion of the flexible tube 2 easily, and after the insertion, the flexible tube 2 bulges outward at the seal promoting rib 14a. It becomes the shape like.

After this state, the tightening cap 12 is tightened toward the joint body 11 side.
At this time, in the above-described embodiment, since the tightening cap 12 has a so-called cap nut shape in which it is directly screwed into the joint body 11, it is tightened while rotating it in the tightening direction. It is going. When this is done, as shown in FIG. 3D, the seal sleeve 1
3 is pushed and deformed by the inner surface of the inner tightening flange 19 of the tightening cap 12, and its inner taper 13a has a tube end along the taper guide surface 15a provided on the outer cylinder 15 of the joint body 11. You will be guided to get into the receiving part 16 side. As a result, the end portion of the flexible tube 2 is pressed by the seal sleeve 13 from the outer periphery in a state of being tightly tightened, and the seal is completed.

[0023]

Other Embodiments The tube connection structure of the present invention is based on the above-described form, but there is still another modification shown in FIG. In this structure, the inner cylinder 14 of the joint body 11 is configured as a member separate from the joint body 11. In this case, a main body joint surface 14c having a shape in which the inner portion is recessed is formed with respect to the inner cylinder 14, and the inner cylinder joint surface 1 having substantially the same tapered shape on the joint body 11 side.
1a is formed in advance. In this case, the joint main body 11 can be processed relatively easily, and the dimension setting of the inner cylinder 14 and the like can be configured separately from the joint main body 11. Therefore, various selections can be made in terms of dimensional specifications. .

In the embodiment shown in FIG. 5, when the tightening cap 12 is tightened, the tightening cap 12 is not directly screwed into the joint body 11, but is tightened by using the tightening bolt B separately. It is a thing. The point is that the tightening cap 12 may be configured to be able to approach the joint body 11. The connection structure of the present invention is configured as a joint by a member separate from the functional member such as the valve V, or may be directly formed on the functional member.

[0025]

The tube connection structure of the present invention has the specific structure as described above, and by providing the seal sleeve 13 separately, the tube end can be completely sealed, and the tube endurance is improved. Performance such as vibration is also improved. In particular, it is possible to completely avoid liquid leakage at the connection site, disconnection of the flexible tube 2, and the like. In addition, there is no dead space that causes a liquid pool, and the properties of chemicals to be supplied are not impaired. Further, since the inner tube Sb of the abacus beads which has the middle part bulging outwardly unlike the conventional one is not used for the flexible tube 2, the assembling work can be performed very easily, and a jig or the like is additionally required for the work. Not. Further, since the tube end receiving portion 16 is formed so as to be cut inward, the size of the joint portion can be shortened as a whole, and a compact product can be obtained. In addition, for example, if the valve V, which is a functional component, is integrated, the device can be made more compact.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an exploded tube connection structure of the present invention.

FIG. 2 is a partially broken side view showing the assembled state of the same as above and b-
It is an arrow b view.

FIG. 3 is a partially cutaway side view showing the above assembling order.

FIG. 4 is a partially cutaway side view showing another embodiment of the above.

FIG. 5 is a partially cutaway side view showing still another embodiment of the same.

FIG. 6 is a partially cutaway side view showing an example of a conventional type.

FIG. 7 is a partially cutaway side view showing still another four conventional examples.

[Explanation of symbols]

 1 Joint 2 Flexible Tube 11 Joint Body 11a Inner Cylinder Joint Surface 12 Tightening Cap 13 Seal Sleeve 13a Inner Tapered 13b Clamping Side Inner Taper 14 Inner Cylinder 14a Seal Promoting Rib 14b Tapered Surface 14c Body Joint Surface 15 Outer Cylinder 15a Tapered guide surface 15b Male thread 16 Tube end receiving section 17 Functional member connecting section 18 Female thread ring section 18a Female thread 18b Hand tightening section 19 Inner flange for tightening 19a Tube insertion hole 19b Wrench hooking section B Bolt V Valve

Claims (6)

[Claims] 1. A structure in which a flexible tube is connected to another functional member through a joint, wherein the joint includes a joint body and a tightening cap, and a flexible tube is provided on a connection side of the joint body. An inner cylinder for externally fitting and an outer cylinder for externally fitting the tightening cap are provided, and a space formed by these is used as a tube end receiving portion. Further, the inner cylinder has an outer peripheral portion on the open side. A seal-promoting rib is provided on the circumference, an inner conical taper guide surface is formed on the open end side of the outer cylinder, and the tightening cap has a tightening inner flange on the tube insertion side. Furthermore, a joint and a flexible seal sleeve, which is separate from the flexible tube, are externally fitted to the outer circumference of the flexible tube, and the flexible tube is externally fitted to the inner cylinder. In this state, the seal sleeve is externally fitted to the flexible tube at that position, and the tightening cap is tightened in this state to deform the seal sleeve, and the deformed seal sleeve presses the flexible tube to the inner cylinder. A tube connection structure characterized by being assembled in a state. 2. The tube connecting structure according to claim 1, wherein the inner cylinder is formed integrally with the joint body. 3. The tube connection structure according to claim 1, wherein the inner cylinder is formed separately from the joint body. 4. The insertion-side end of the inner cylinder is tapered in a tapered shape.
Alternatively, the tube connection structure described in 3 above. 5. The tightening cap is a tightening nut that is screwed into the joint body, and has a hand tightening portion and a wrench hooking portion formed on the outer peripheral portion.
The tube connection structure according to 2, 3, or 4. 6. The tube connection structure according to claim 1, 2, 3, 4, or 5, wherein the joint is made of a fluororesin.