JPH0419491A - Tube fitting - Google Patents

Abstract

PURPOSE:To obtain a tube fitting provided with a bending part for liquid-tight holding by inserting a fitting part of a fitting main body provided with circular grooves into a large-diameter part formed on a plastic tube, loosely fitting a press-fitting ring to a tube, press-fitting the ring to the circular grooves of the fitting main body, and thereby forming a tube bending part. CONSTITUTION:A large-diameter part 2 is formed on an end of a tube l made of plastic such as fluororesin. A fitting main body 4 made of fluororesin or the like is inserted into the large-diameter part 2, on which main body 4 circular grooves 3 are formed. A press-fitting ring 6 made of fluororesin or the like is loosely fitted to the outre face of the large-diameter part 2. During this loosely fitting, the press-fitting ring 6 is press-fitted to the circular grooves 3 of the fitting main body 4 saindwiching the large-diameter part 2, and an intermediate part of the large-diameter part 2 is sandwiched between the outer peripheral surfaces of the circular grooves 3 and an inner surface of the press-fitting ring 6 to form a tube bending part 7. As a result, neither sealing ability nor escape- prevention strength is deteriorated, and additional fastening is disused.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a tube joint, and more specifically to a tube joint suitable as a joint for synthetic resin tubes, particularly fluororesin tubes.

[Prior art] This type of tube joint has been conventionally used, for example, in the
There is one described in Japanese Patent No. 52391.

This conventional technology includes a joint body, a cap nut for attaching a synthetic resin hard pipe to the joint body, and a trapezoidal seal ring that fits into a tapered hole communicating with a pipe insertion hole in the joint body. and a trapezoidal taper ring provided with a wide slanted groove that fits into the taper hole communicating with the female threaded portion of the cap nut, applying a compressive force to the pipe in the direction of its center and deforming the outer periphery of the pipe. This pipe joint is characterized in that it is fixed by holding the pipe joint in place.

[Problems to be Solved by the Invention] The conventional technology described above measures sealing and prevention by inserting a taper ring or seal ring into the tube, but since there is no insert inside the tube, There were problems in that the biting was weak, the tube easily came off from the joint body, and the sealing performance changed with temperature cycles, so so-called "retightening" was required, making maintenance troublesome.

In order to eliminate each of the above-mentioned problems, the present invention provides a press-fit ring which is formed in advance on a tube and inserted into an insertion portion protruding from the joint body, and which is loosely inserted into the tube in advance. The middle part of the large diameter part is inserted into the joint body by firmly pressing it into the groove ring of the joint body with the large diameter part in between, against the elasticity of each material of the tube, insertion part, or press-fit ring. It is an object of the present invention to provide a tube joint in which a tube bending part for preventing slippage and maintaining liquid tightness is tightly sandwiched between the outer circumferential surface of a groove ring and the inner circumferential surface of a press-fit ring.

[Means for Solving the Problems] An object of the present invention described above is to attach a tube by forming a deformed part on the tube to form a tube joint that prevents the tube from coming off. A large diameter part is formed at the end of the tube made of aluminum, and the insertion part of the fitting body, which has a groove ring and is made of fluororesin or the like, is inserted into the large diameter part, and is loosely inserted into the tube. , and by press-fitting a press-fit ring made of fluororesin or the like into the groove ring of the joint body with the large diameter part in between, the middle part of the large diameter part of the tube is inserted into the groove ring of the insertion part of the joint body. This is achieved by tightly sandwiching the outer circumferential surface and the inner circumferential surface of the press-fit ring to form a tube bent portion.

Further, a cap nut, which has been inserted into the tube in advance, is screwed into the male thread portion formed in the insertion portion of the joint body using its female thread portion, and the tube is inserted into the end surface of the insertion portion using the inner surface of the shoulder portion of the cap nut. It is also possible to hold the refraction tightly.

[Function] After inserting the press-fit ring into the tube in advance, inserting the pre-formed large diameter part of the tube into the insertion part of the joint body, and then inserting the groove ring formed in the insertion part. By tightly press-fitting the press-fit ring into the outer circumferential surface against the elasticity of the material of each member, the outer circumferential surface of the groove ring of the joint body and the inner circumferential surface of the press-fit ring are tightly attached to the middle part of the large diameter portion. A sandwiched tube bend can be formed.

Since this bent tube part is tightly held between the corner of the press-fit ring and the corner of the groove ring, the tube is kept liquid-tight with respect to the joint body, and the tube and press-fit ring cannot be pulled out from the joint body. There is no.

Furthermore, by tightly bending and holding the middle part of the tube protruding from the end face of the insertion part of the joint body to the above end face with the inner surface of the shoulder of the cap nut, the press-fit ring including the tube can be prevented from coming out from the joint body. It's fleeting.

[Example] Examples will be described with reference to the drawings.

First of all, the basic structure of this invention is that the tube is sometimes attached by forming a deformed part on the tube to form a tube joint that prevents the tube from coming off. 2 and 3 using a heat forming jig a as shown in the figure.
A large diameter portion 2 as shown in the figure is formed.

Then, a joint body 4 molded from fluororesin as shown in FIG. 4 with a groove ring 3 formed in the large diameter portion 2 is inserted through its insertion portion 5.

Further, as shown in FIG. 4, the press-fit ring 6, which has been loosely inserted into the tube 1 in advance, is moved downward using a lowering jig, and after passing through the state shown in FIG. It begins to be press-fitted into the outer peripheral surface of the insertion portion 5 of the joint body 4.

Then, as the above press-fitting continues, the large diameter portion 2 of the tube 1 is connected to the outer peripheral surface of the groove ring 3 of the insertion portion 5 and the press-fit ring 6.
A tube joint according to the present invention is obtained by tightly sandwiching the tube with the inner circumferential surface of the tube to form a tube bent portion 7 as shown in FIG.

Further, a cap nut 8, which has been inserted into the tube 1 in advance, is screwed into the male thread portion 5a of the joint body 4 with its female thread portion 8a, and the inner surface of the shoulder portion 9 of the cap nut 8 is inserted as shown in FIG. Another example of the tube joint according to the present invention is constructed by tightly bending and holding the tube 1 on the end face of the press-fit ring 6.

The press-fit ring 6 is made of plastic such as fluororesin or metal, and the joint body 4 is made of metal or plastic such as fluororesin.

FIG. 8 shows still another embodiment of the present invention, in which the insertion portion 5 of two couplings 4.4 is omitted in place of the coupling body 4 of the previous embodiment and the male threaded portion 5a is omitted. This is an example in which piping is connected between .

In this case, the tube 1 may have the same diameter as the insertion portion of the joint, as shown by the chain line, and the large diameter portion 2 may not be formed.

That is, in this case, the press-fit ring 6 is made in advance with a heating jig or the like to have an inner diameter larger than the diameter of the tube 1 (the part shown by the imaginary line), and the above-mentioned diameter is set in the groove ring 3 with the tube 1 in between. By reheating the press-fit ring 6 with the diameter-enlarged press-fit ring 6 facing forward, the diameter can be reduced as shown in FIG. The joint can be tightly joined to the joint body 4 in the same way as when it is press-fitted.

In FIG. 8, portions with the same reference numerals as those in the above embodiment indicate portions having the same effect.

The structure of the present invention is as described above. Next, the usage condition and operation of the tube joint according to the present invention will be explained below.

First, the press-fit ring 6 is inserted into the tube 1 in advance, and then the tube 1 is preformed as shown in FIG. 3 through the conditions shown in FIGS. A large diameter portion 2 is inserted into the insertion portion 5 of the joint body 4 as shown in FIG.

After the press-fit ring 6 is in the state shown in FIG. 5, the tube 1 and
By forcibly press-fitting the insertion part 5 and the press-fitting ring 6 against the elasticity of each material, it can be fitted with a single click, and the middle part of the large-diameter part 2 can be fitted with a single click, as shown in FIG. As shown in FIG. 6, the tube bent portion 7 can be formed to be tightly sandwiched between the outer peripheral surface of the groove ring 3 of the insertion portion 5 and the inner peripheral surface of the press-fit ring 6.

Since this tube bent portion 7 is tightly held between the corner of the groove ring 3 and the corner of the press-fit ring 6 as shown in FIG. 6, the tube I is held liquid-tight with respect to the joint body 4.
Moreover, it will not come off from the insertion part 5 of the joint body 4.

Furthermore, the middle part of the tube 1 protruding from the end face of the insertion part 5 of the joint body 4 is tightly bent and held at the end face by the inner surface of the shoulder part 9 of the cap nut 8, as shown in FIG.
The press-fit ring 6 including the tube 1 will never come out of the joint body 4.

In the example shown in FIG. 8, the press-fit ring 6 is inserted into the groove ring 3 of the joint body 4.
Since the tube 1 is tightly pressed between the two, the press-fit ring 6 and the tube 1 will not come out accidentally from the joint 4 even if the cap nut 8 is omitted.

Furthermore, if the press-fit ring 6 is made of fluororesin, by actively utilizing its heating deformability, the press-fit ring 6 can be preheated to a diameter shown in FIG. 5 or a slightly larger diameter than this diameter. If the press-fit ring 6 is loosely inserted into the tube 1 and exposed to the groove ring 3 with the Chicove large-diameter portion 2 in between, the press-fit ring 6 is reheated to reduce its diameter, as shown in Fig. 6. As shown, the tube 1 can be tightly sandwiched and press-fitted onto the outer peripheral surface of the groove ring 3.

Particularly in this case, it is not necessary to press-fit the press-fit ring 6 mechanically or physically as in the previous embodiment, so that the press-fitting operation can be carried out even more easily.

[Effects of the Invention] Since the present invention is configured as described above, it produces the effects described below.

After inserting the press-fit ring 6 into the tube l in advance, insert the large-diameter portion 2 previously formed in the tube 1 into the joint body 4 through its insertion portion 5, and insert the press-fit ring 6 into the large diameter portion 2. By forcefully inserting the tube 1, the press-fit ring 6, and the insertion portion 5 into the tube 1, the press-fit ring 6, and the insertion portion 5 with the diameter portion 2 in between, the fitting can be achieved with a single snap and lock. A tube bent portion 7 can be formed in the middle portion of the diameter portion 2, which is tightly sandwiched between the outer circumferential surface of the groove ring 3 of the insertion portion 5 of the joint body 4 and the inner circumferential surface of the press-fit ring 6.

Since this tube bending part 8 is tightly held between the corner of the press-fit ring 6 and the corner of the groove ring 3, the tube l is held liquid-tight with respect to the joint body 4 and can be pulled out from the joint body 4. Therefore, the sealing performance and pull-out strength are not impaired by temperature cycles or aging, and the so-called "
The first advantage is that maintenance is easy because there is no need to retighten, and hard synthetic resin tubes are less likely to come off.
It has the effect of

In particular, with this invention, as mentioned above, even without using a cap nut, the tube can be reliably joined to the joint body by locking it with a single snap with a press-fit ring or by reheating, making it easier to connect piping at the construction site. A second effect is that workability is significantly improved compared to the conventional example.

According to claim 2, in addition to the above-mentioned effects, the intermediate portion of the tube 1 protruding from the end face of the insertion portion 5 of the joint body 4 is tightly bent at the end face by the inner surface of the shoulder portion 9 of the cap nut 8. By holding the tube 1, the press-fit ring 6 is further prevented from slipping out from the joint body 4, which has the effect of stably maintaining the function of the joint over a long period of time.

[Brief explanation of the drawing]

Each of the figures shows an embodiment of the present invention. Figure 1 is a cross-sectional view of a tube and a heat-forming jig, and Figure 2 is a tube that is press-fitted into a heat-forming jig to form a large diameter part. cross section,
Figures 3 and 4 are cross-sectional views showing the procedure for inserting the tube into the joint body, Figure 5 is a cross-sectional view showing the moment when the press-fit ring is press-fitted into the joint body with the tube in between, and Figure 6 is a cross-sectional view showing the procedure for inserting the tube into the joint body. FIG. 7 is a cross-sectional view of a tube joint in which a cap nut is screwed together, and FIG. 8 is a cross-sectional view showing another example of a tube joint. ...Tube...Large diameter part...Groove ring...Joint body...Insertion part/Male thread part 6...Press-fit ring 7...Tube bent part 8...Cap nut 8a...Female Neck part 9...Shoulder part Applicant Isao Takahashi of Fuu Kogyo Co., Ltd.

Claims (1)

[Claims] 1. A tube joint in which the tube is prevented from coming off by forming a deformed portion when the tube is attached,
A large diameter portion 2 is formed at the end of a tube 1 made of plastic such as fluororesin, and a groove ring 3 is formed within this large diameter portion 2, and a joint body 4 made of fluororesin or the like is inserted. 5, and a press-fit ring 6 loosely inserted into the tube 1 and made of fluororesin or the like is press-fitted into the groove ring 3 of the joint body 4 with the large-diameter portion 2 in between.
A tube joint formed by tightly sandwiching the middle portion of the large diameter portion 2 between the outer peripheral surface of the groove ring 3 of the insertion portion 5 and the inner peripheral surface of the press-fit ring 6 to form a tube bending portion 7. 2. Screw the cap nut 8, which has been inserted into the tube 1 in advance, into the male thread portion 5a formed on the joint body using the female thread portion 8a, and insert the tube 1 into the inner surface of the shoulder portion 9 of the cap nut 8. 2. The tube joint according to claim 1, wherein the fitting portion 5 is tightly bent and held at the end face thereof.