JP2006090420A - Resin tube and pipe joint structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify construction while maintaining a convenience in inserting a pipe into a resin tube. <P>SOLUTION: When the pipe 20 is inserted into the resin tube 10 to link a fluid passage, an insertion portion 22 of the pipe 20 is inserted into a joint portion 12 of the resin tube 10. A joint part 14 and a straight tube part 13 of the joint portion 12 are in the condition of the insertion portion 22 being inserted with no gap to the inner peripheral face or are expanded by the insertion portion 22. In the joint part 14, an engaging boss 24 of the insertion portion 22 is located inside its crest portion 14a. The engaging boss 24 annularly uprising on the outer peripheral side of the pipe has contact with a valley portion 14b extending from the crest portion 14a of the joint part 14. It is reliably functioned to prevent the come-off of the pipe because the backward movement (come-off) of the pipe 20 is interrupted by the valley portion 14b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coupling structure for connecting a fluid flow path by inserting a pipe into a resin tube.

  In this type of connection structure, the convenience of pipe insertion is required, and so-called quick connectors are often used. However, such a connector is easy to insert, but has a large number of parts, and there is a limit to cost reduction due to an increase in man-hours for assembly and the like. In response to such a background, it has been proposed to provide a connector function to the resin tube itself (for example, Patent Document 1).

JP 2000-274579 A

  However, in the above-mentioned patent document, it has a bellows part provided in the middle of the straight pipe line and a connector part at the end of the straight pipe line, and this connector part has an insertion end shape of the pipe to be inserted. It has a unique expanded shape that matches the model. Therefore, when molding the resin tube, not only the molds for molding the bellows part and the connector part are required separately, but also because the mold structure is complicated, the mold is changed due to the change of the pipe insertion end shape, etc. It has been pointed out that production management becomes complicated.

  In addition, the resin tube and the pipe are sealed with an O-ring mounted inside the extended connector portion. Therefore, it is necessary to consider that the O-ring does not tilt when the O-ring is mounted, which is complicated. In addition, quality control is also required for the shape of the connector portion in order to ensure sealing performance by the O-ring, which is complicated. In addition, the O-ring at the seal location acts to suppress backlash of the pipe, but since the seal location is the tube end away from the tip of the pipe, backlash tends to occur at the end of the pipe, and the sealing function also deteriorates. Expect to get up.

  An object of the present invention is to solve the above-described problems of the prior art and to simplify the configuration while maintaining the simplicity of pipe insertion into a resin tube.

  In order to solve at least a part of such problems, the coupling structure of the present invention inserts a pipe insertion portion into a coupling portion of a tube path end portion of the resin tube when the pipe is inserted into the resin tube to connect the fluid flow path. To do. At this time, there is no gap between the insertion portion and the inner peripheral surface of the coupling portion. At the opening end of the coupling portion in this state, the engagement ridge of the pipe insertion portion is positioned inside the peak portion at the opening end. To do. Since this engaging bulge protrudes on the outer peripheral side of the pipe, it comes into contact with a trough that continues to the crest at the open end, and the retreat of the pipe (pipe disconnection) is blocked by the trough and functions as a retaining. In other words, after the pipe insertion portion is in a state where there is no gap with the inner peripheral surface of the coupling portion, the pipe insertion portion is resinated until the engagement ridge of the pipe is positioned inside the peak portion of the coupling portion opening end. By simply inserting the tube into the connecting portion of the tube, the connection between the resin tube and the pipe is completed, and the pipe is prevented from being pulled out.

  Further, the seal between the pipe and the resin tube is made by a seal member installed in a groove formed in the pipe side. Therefore, since the seal member is installed on the pipe side, the operation is simple. Moreover, since the sealing by the sealing member is performed between the expanded coupling portion and the insertion portion, and the sealing portion is near the intermediate position between the engagement ridge and the insertion portion end in the pipe, the pipe tip ( The effectiveness of suppressing rattling at the end of the insertion portion is increased. As a result, the sealing function can be maintained.

  And, as described above, in order to facilitate simple pipe insertion and pipe removal, maintaining the sealing function, in the present invention, while forming a peak / valley part equivalent to the bellows part at the joint opening end of the resin tube, The seal member is merely located near the intermediate position between the engaging ridge in the pipe and the end of the insertion portion. Therefore, the structure can be simplified, and the mold shape at the time of forming the resin tube can be matched with the irregularities for forming the bellows part, so that the mold structure can be simplified and the manufacturing cost can be reduced. Can contribute.

  Moreover, in the bellows part provided in the middle of the straight tube path, if the bellows part is cut so that one peak and one valley part remain on the straight tube path side, the straight tube path These portions can be used as the connecting portion in the present invention. Therefore, the above-described resin tube of the present invention can be obtained by a simple method of cutting the bellows portion. This also simplifies the mold configuration.

  In the coupling structure configured as described above, the expansion margin of the coupling portion when inserting the insertion portion of the pipe into the coupling portion of the resin tube is an expansion margin in a range where the insertion portion can be inserted into the coupling portion at room temperature. It is preferable to adjust the outer diameter of the insertion portion. That is, workability can be prevented from being hindered by setting the insertion portion to an appropriate diameter compared to the coupling portion.

  Next, in order to further clarify the configuration and operation of the present invention, preferred embodiments of the present invention will be described below. FIG. 1 is an explanatory view schematically showing a resin tube 10 according to the embodiment, FIG. 2 is an explanatory view showing an aspect of a bellows portion of the resin tube 10, and FIG. It is explanatory drawing to do.

  As shown in the figure, the resin tube 10 of the embodiment has a coupling portion 12 at both ends of the tube path, and a bellows portion 16 between both the coupling portions. The connecting portion 12 includes a straight straight pipe portion 13 and a connecting part portion 14 at an open end, and receives the insertion of a pipe 20 to be described later and connects to the pipe to connect the pipe and the fluid path. The bellows portion 16 includes a peak portion 16a raised around the outer periphery of the tube and a valley portion 16b depressed around the outer periphery alternately and continuously. In this case, the bellows part 16 has a continuous bellows part 17 of the peak part 16a and the valley part 16b as shown in FIG. 2 in addition to the form in which the peak part 16a and the valley part 16b are continuous in the entire path. It is also possible to have a plurality of straight path portions 18 interposed therebetween.

  As shown in FIG. 3, the resin tube 10 includes a crest portion 14 a and a trough portion 14 b that are equivalent to a crest portion 16 a and a trough portion 16 b that the bellows portion 16 has a coupling part portion 14 that hits the tip (open end) of the coupling portion 12. The valley 14b is provided on the end side. That is, the valley portion 14b is formed so that one valley remains on the inner side of the tube on the end side of the coupling part portion 14.

  The resin tube 10 having the above-described form is molded using various resins. For example, PA (Polyamide), PE (Polyethylen), EVOH (ethylene-vinyl alcohol copolymer), PPS (Polyphenylene Sulfide), etc., A fluororesin, a polyester resin, or the like can be used. Since these resins are resistant to fuel oil, the resin tube 10 can be used as a fuel supply system tube in a vehicle. The resin tube 10 can be a single-layer tube of the above-mentioned resin, and can also be a multilayer tube using various resins.

  In this embodiment, assuming that the resin tube 10 is used as a fuel system tube or the like, the material is selected from the resins described above, the inner diameter is about 30 mm, and the tube thickness is the same as the pipe 20 described later. In consideration of sealing performance, insertion workability, etc., the thickness was set to 2 mm. The tube inner diameter and the tube wall thickness are not limited to the above dimensions, and particularly the tube wall thickness is preferably 2 to 6 mm from the viewpoint of sealing performance and insertion workability.

  The pipe 20 is made of resin, and an end portion thereof is used as an insertion portion 22 to be inserted into the coupling portion 12 of the resin tube 10, and an engagement ridge 24 is provided at a position separated from the end portion of the insertion portion 22 by a predetermined distance L. . This engagement ridge 24 is formed in an annular bulge on the outer peripheral side of the pipe and functions as a stopper for the insertion pipe.

  In this embodiment, the outer diameter of the pipe 20, specifically, the outer diameter of the insertion portion 22 is about 31 mm, and the expansion allowance of the resin tube 10 by pipe insertion is about 1 mm. Such an expansion allowance is preferable from the viewpoint of workability because the insertion portion 22 of the pipe 20 can be easily inserted into the coupling portion 12 of the resin tube 10 at room temperature. In addition, if said expansion allowance is the range of 0-2 mm, the insertion part 22 of the pipe 20 can be inserted in the joining part 12 of the resin tube 10 without trouble at normal temperature.

  The pipe 20 is a groove formed in a ring shape around the outer periphery of the pipe in the vicinity of an intermediate position between the engagement ridge 24 and the end of the insertion portion 22, specifically in the middle of the distance L of the engagement ridge 24. 25, and a seal member 26 is mounted in the groove. That is, since the pipe 20 is inserted into the resin tube 10 with the seal member 26 mounted, considerations such as avoiding the inclination of the seal member are given when the pipe is mounted. The seal member 26 is formed of elastic rubber or the like, and exhibits a sealing function for the resin tube 10 in a state where the pipe 20 is inserted into the resin tube 10.

  When the pipe 20 is inserted into the resin tube 10 to connect the fluid flow paths, the insertion portion 22 of the pipe 20 is inserted into the coupling portion 12 in the resin tube 10. With the insertion of the insertion portion 22, the coupling part portion 14 and the straight pipe portion 13 of the coupling portion 12 are both expanded. In the expanded coupling part portion 14, the engagement bulge of the insertion portion 22 is formed inside the peak portion 14 a. 24 is located. Since the engaging ridges 24 are annularly bulged on the outer peripheral side of the pipe, they come into contact with the valley portions 14b following the ridge portions 14a in the connecting part portion 14, and the pipes 20 are retracted (pipe disconnection) by the valley portions 14b. Is blocked and functions reliably as a pipe stopper. Therefore, the resin tube can be simply inserted by inserting the insertion portion 22 until the engagement ridge 24 is located on the inner side of the mountain portion 14a of the coupling part portion 14 while expanding the coupling portion 12 of the resin tube 10 with the insertion portion 22 of the pipe 20. The connection between the pipe 10 and the pipe 20 is completed, and the pipe is prevented from being pulled out. In this case, the coupling part portion 14 is temporarily expanded by the engagement ridge 24, but returns to its original shape because it is an elastic deformation region in the expansion allowance described above. Therefore, the above-described retaining function can be reliably exhibited.

  In the state where the pipe is inserted in this manner, the seal member 26 already attached to the insertion portion 22 exhibits a sealing function between the insertion portion 22 and the coupling portion 12, specifically, the straight pipe portion 13. That is, in order to exhibit the sealing function, it is only necessary to insert the pipe after mounting the sealing member 26 in the groove 25 in the insertion portion 22, so that the work required to exhibit the sealing function becomes simple. In addition, the sealing by the sealing member 26 is performed between the expanded coupling portion 12 (specifically, the straight tube portion 13) and the insertion portion 22, and the sealing portion is the engagement ridge 24 and the insertion portion 22 in the pipe 20. Since it is in the vicinity of the intermediate position of the end, even if vibration or the like occurs in the pipe 20, the effectiveness of suppressing rattling at the tip of the pipe (the end of the insertion portion 22) is increased. As a result, the sealing function can be maintained.

  As described above, in this embodiment, in order to easily insert and remove the pipe at normal temperature and to maintain the sealing function, the connecting part portion 14 of the resin tube 10 is formed with a peak portion 14 a equivalent to the bellows portion 16. While forming the valley portion 14 b, the seal member 26 is merely positioned near the middle position between the engagement ridge 24 and the insertion portion 22 end of the pipe 20. Therefore, the configuration can be simplified. In addition, since the shape of the peak portion and the valley portion is the same between the bellows portion 16 and the coupling part portion 14, the mold shape at the time of forming the resin tube may be matched with the unevenness for forming the bellows portion 16. For this reason, it can contribute to the simplification of a metal mold | die structure and a reduction in manufacturing cost.

  Here, the manufacturing method of the resin tube 10 is demonstrated. FIG. 4 is an explanatory view for explaining one manufacturing method of the resin tube 10. As shown in the figure, in this manufacturing method, the resin tube is molded so that the straight straight pipe portion 13 and the bellows portion 16 are mixed. In this case, the mold has an uneven mold shape capable of continuously forming the peak portions 16a and valley portions 16b of the bellows portion 16, and a straight mold shape for forming the straight pipe portion 13. In the bellows portion 16 of the resin tube thus molded, the bellows portion 16 is cut along the cut line shown in the drawing. This cut line is defined so that one crest 16a and a trough 16b remain after the straight pipe portion 13, and after cutting, the connecting part 14 having the crest 14a and the trough 14b is straight. The connecting portion 12 is formed by the straight pipe portion 13 and the connecting part portion 14. That is, the resin tube 10 described above can be easily manufactured by a simple method of cutting the bellows portion 16. Moreover, since the mold used has only to have an uneven mold shape and a straight mold shape as described above, the mold configuration can be simplified.

  The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof.

It is explanatory drawing which shows schematically the resin tube 10 of an Example. 3 is an explanatory diagram illustrating an aspect of a bellows portion in the resin tube 10. FIG. It is explanatory drawing explaining the mode of the coupling | bonding of the resin tube 10 and the pipe 20. FIG. 3 is an explanatory diagram for explaining one manufacturing method of the resin tube 10. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Resin tube 12 ... Connection part 13 ... Straight pipe part 14 ... Connection part part 14a ... Mountain part 14b ... Valley part 16 ... Bellows part 16a ... Mountain part 16b ... Valley part 17 ... Bellows parts 18 ... Straight path part 20 ... Pipe 22 ... Insertion part 24 ... Engagement ridge 25 ... Groove 26 ... Sealing member

Claims (2)

A coupling structure that connects a fluid flow path by inserting a pipe into a resin tube,
The resin tube is
A straight joint located at the end of the tube path to receive the insertion of the pipe;
It is located in the middle of the straight tube path, and has a bellows part formed continuously by a peak part protruding around the outer periphery and a valley part depressed around the outer periphery,
The pipe is
An insertion portion that is inserted into the coupling portion in a state in which no gap occurs with the inner peripheral surface of the coupling portion;
An engaging bulge for preventing pipe removal formed to bulge toward the outer periphery of the pipe at a position separated from the end of the insertion portion;
A groove formed in a ring shape around the outer periphery of the pipe in the vicinity of an intermediate position between the engagement ridge and the end of the insertion portion;
A sealing member that is installed in the groove and exhibits a sealing function with respect to the expanded joint portion;
The resin tube is
At the opening end of the coupling portion, provided with a crest and a trough equivalent to the crest and trough that the bellows has, with the trough on the end side,
The pipe is
The joint structure of the resin tube and the pipe, wherein the engagement ridge is positioned inside the peak portion of the resin tube at the end portion of the joint portion and is prevented from being removed by the valley portion. The coupling structure according to claim 1,
The outer diameter of the insertion portion of the pipe is:
The resin tube is set such that the expansion allowance of the insertion portion when the insertion portion is inserted into the connection portion of the resin tube is an expansion allowance in a range in which the insertion portion can be inserted into the connection portion at room temperature. Pipe connection structure.

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