JP2008202767A - Pipe connection structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe connection structure capable of connecting a resin tube to a pipe body in irrotational state without using a special irrotational tool. <P>SOLUTION: A bulged portion 7 is formed to be bulged from an insertion end 9 of the first pipe body 1, and plane portions 19, 19 are provided on both sides of the bulged portion 7 at radially symmetrical positions. The insertion end 9 of the first pipe body 1 is inserted (press-fitted) into the resin tube 21 in such a relatively tight manner that the resin tube 21 has whole or almost whole contact with the bulged portion 7 including the plane portions 19, 19. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a connection structure between a piping resin tube and a tubular body such as a pipe body, for example, a vehicle under-floor piping (a piping between a resin fuel tube of an automobile and a metal pipe body under the floor).

  For example, fuel pipes of automobiles use flexible rubber hoses that can be bent freely when pipes are connected and that can sufficiently follow relative displacement between members to be connected. However, rubber hoses are heavy. And handling is not good. Therefore, resin pipes that are lightweight and excellent in handleability are also used in automobile fuel piping. When connecting such a resin tube to, for example, a pipe body, a tube connecting portion having an annular retaining protrusion having an acute tip (outer end) is provided on one side, and the pipe body is connected to the pipe body from the other side. A quick connector configured to be connected with one touch is used, and after connecting a resin tube to the tube connecting portion, the quick connector is connected to the pipe body.

  However, if a quick connector is used to connect the pipe body and the resin tube, the pipe connection point becomes large in diameter and the part placement space is compressed. The connector may be damaged. Therefore, a connection method (direct attachment method) in which a resin tube (or tube) is directly connected to a pipe body (or cylindrical body) without using a quick connector is also used (see, for example, Patent Documents 1 to 3). When directly connecting the resin tube to the pipe body, a bulge is formed on the outer periphery of the insertion end of the pipe body, and the resin tube that is tightly fitted to the outer periphery of the insertion end is retained by this bulge. In addition, the sealing property between the pipe body and the resin tube is ensured.

JP 2006-124665 A Japanese Patent No. 3567790 Japanese Patent No. 2673418

  By the way, since the resin tube is less elastic than the rubber hose, it becomes easier to rotate relative to the counterpart member, and when the resin tube rotates after long-term deterioration, the seal between the resin tube and the counterpart member Sex is reduced. Therefore, the rotation prevention between the resin tube and the pipe body is performed using a special rotation prevention device (for example, one using a bent portion of the resin tube). The diameter of the pipe connection part will increase.

  Then, this invention aims at provision of the piping connection structure which can connect the resin tube to a pipe body in the non-rotating state, without using a special anti-rotation tool.

  In order to achieve this object, the pipe connection structure of the present invention is a pipe connection structure in which a resin tube for piping is tightly fitted and connected to the outer periphery of the insertion end of the pipe body. An annular bulge portion is provided for retaining the bulge, and the bulge portion is formed in a non-circular cross section (a cross section by a radial cut surface). The pipe body is made of metal, for example. For example, the outer surface of the bulge portion is formed in a noncircular cross section. The resin tube is deformed to expand along the bulge part or the outer surface of the bulge part, that is, deformed into a non-circular cross section at the bulge part, and is fitted to the insertion end of the pipe body. Therefore, since the bulge part of the pipe body and the resin tube constitute a non-circular fitting structure, the pipe body and the resin tube are connected to be prevented from rotating. The bulge portion can be formed, for example, in a cross-sectional shape having a flat cutout portion (or cutout portion) in a circular part. Further, the bulge portion can be formed to have non-bulged portions at a plurality of locations in the circumferential direction. In this case as well, the bulge portion has a non-circular cross section that is concave at the non-bulged portion with respect to, for example, a circle.

  When a plurality of bulge parts are formed at intervals in the axial direction at the insertion end of the pipe body, it is not always necessary to form all the bulge parts in a non-circular cross section. For example, the pipe connection structure according to the present invention is a pipe connection structure in which a resin tube for piping is tightly fitted and connected to the outer periphery of the insertion end of the pipe body, and the outer end of the insertion end is provided with a tip and an intermediate An annular first bulge portion and a second bulge portion are provided in each of the portions, and the first bulge portion is formed in a circular shape in a cross section (a cross section by a radial cut surface), and the second bulge portion Can be formed in a non-circular cross section (cross section by a cut surface in the radial direction). By ensuring that one (part) bulge part has a circular cross section and the other (remaining) bulge part has a non-circular cross section, one (part) bulge part has sufficient retaining and sealing properties. The other (remaining) bulge part can be secured with a retaining property (or retaining property and sealing property) and a detent property.

  If the pipe connection structure of the present invention is used, the resin tube and the pipe body can be effectively prevented from rotating without increasing the diameter of the pipe connection portion.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an insertion end portion of a first pipe body used in a first pipe connection structure according to the present invention, and FIG. 2 is a perspective view showing a first pipe connection structure using the first pipe body. FIG.3 and FIG.3 is sectional drawing which shows the 1st piping connection structure.

  The first pipe body 1 is made of, for example, metal, and is fixed to the internal device so as to protrude from the internal device of the automobile (for example, a vehicle underfloor pipe, not shown). One end (tip side) in the axial direction of the first pipe body 1 is formed by connecting an annular opening side portion 5 to one end in the axial direction of an end portion body 3 having a constant inner diameter and outer diameter and extending elongated. A bulge portion 7 (second bulge portion) protruding outward in the radial direction is formed in an intermediate portion of the portion main body 3 so as to be formed as an insertion end portion 9. The opening side portion 5 has a conical shape from a tip opening portion 11 having a diameter smaller than that of the end body 3 to a peak portion 13 having a diameter larger than that of the end body 3 toward the other side in the axial direction (bulge portion 7 side). The diameter is increased, and the diameter is reduced in a conical shape from the peak portion 13 toward the other end in the axial direction until the end portion 3 is connected. Therefore, an annular projecting portion 15 (first bulge portion) is formed at the other end portion in the axial direction of the opening side portion 5.

  The bulge portion 7 is annular (annular) so that it protrudes larger than the annular protrusion 15, that is, the peak portion 17 is located outside the peak portion 13 of the annular protrusion 15, and The cross section by the cut surface including the axis is formed so as to be an isosceles triangle, but on both sides of the radially symmetric position, plane portions 19, 19 are formed, and between the plane portions 19, 19 The interval is substantially equal to the outer diameter of the end body 3.

  The connection between the first pipe body 1 and the resin tube 21 is achieved by inserting (inserting) the insertion end portion 9 of the first pipe body 1 into the resin tube 21 relatively tightly, or This is done by tightly fitting the resin tube 21 to the outer periphery of the insertion end 9 of the pipe body 1. When the first pipe body 1 and the resin tube 21 are connected, the resin tube 21 comes into close contact with the outer surface of the insertion end portion 9 of the first pipe body 1 or substantially along the annular projecting portion. 15 and the bulge portion 7 prevent the first pipe body 1 from coming off, and the space between the first pipe body 1 is sealed. The resin tube 21 has an inner diameter that is the same as or substantially the same as the outer diameter of the tip opening 11 before fitting.

  The resin tube 21 is fitted over the insertion end 9 of the first pipe body 1 so as to be in contact with the bulge portion 7 in its entirety or substantially entirely, so that the resin tube 21 is a flat surface of the bulge portion 7. The portions 19 and 19 are also in contact with the entire surface or almost the entire surface. Therefore, the resin tube 21 and the first pipe body 1 are relatively prevented from rotating by the contact between the resin tube 21 and the flat portions 19 and 19 of the bulge portion 7.

  4 is a perspective view showing an insertion end portion of a second pipe body used in the second pipe connection structure according to the present invention, and FIG. 5 is a perspective view showing a second pipe connection structure using the second pipe body. FIG.6 and FIG.6 is sectional drawing which shows the 2nd piping connection structure.

  The second pipe body 23 is obtained by changing the configuration of the bulge portion 7 formed at the insertion end portion 9 of the first pipe body 1, and other configurations are the same as the pipe body 1. The same reference numerals are given and description thereof is omitted. The bulge portion 27 formed at the insertion end portion 25 of the second pipe body 23 protrudes larger than the annular projecting portion 15, that is, the peak portion 29 is larger than the peak portion 13 of the annular projecting portion 15. It is formed in an annular shape (annular shape) so as to be located on the outer side and a cross section with a cut surface including the axis line is an isosceles triangle. Here, four non-bulged portions 31 are formed at intervals of 90 degrees. Therefore, in the bulge part 27, it can be considered that four protrusions 33 having an isosceles triangular shape with a narrow width in the circumferential direction are formed at equal intervals in the circumferential direction. Here, the circumferential widths of the protrusion 33 and the non-bulged portion 31 can be made substantially the same. Therefore, the circumferential width of one protrusion 33 and one non-bulged portion 31 can be made approximately one-eighth of the outer periphery of the end body 3.

  The resin tube 21 is in contact with the bulge portion 27 entirely or substantially entirely, that is, the bulge portion 27 is in contact with the bulge portion 27 along or substantially along the concavo-convex shape of the bulge portion 27. Since the resin tube 21 is fitted into the insertion end portion 25, the resin tube 21 falls sufficiently deeply into the non-bulged portion 31 of the bulge portion 27. Therefore, since the circumferential end portion of the protrusion 33 is in contact with the resin tube 21, the resin tube 21 and the second pipe body 23 are relatively prevented from rotating.

  The pipe connection structure of the present invention is suitable for a detent connection between a resin tube and a pipe body in a narrow place such as a fuel tank periphery or a vehicle underfloor pipe.

It is a perspective view which shows the insertion end part of the 1st pipe body used for the 1st piping connection structure which concerns on this invention. It is a perspective view which shows the 1st piping connection structure using a 1st pipe body. It is sectional drawing which shows a 1st piping connection structure. It is a perspective view which shows the insertion end part of the 2nd pipe body used for the 2nd piping connection structure which concerns on this invention. It is a perspective view showing the 2nd piping connection structure using the 2nd pipe body. It is sectional drawing which shows a 2nd piping connection structure.

Explanation of symbols

1 1st pipe body 7, 27 Bulge part 9, 25 Insertion end part
21 Resin tube 23 Second pipe body

Claims (4)

A piping connection structure for connecting a resin tube for piping by tightly fitting it to the outer periphery of the insertion end of the pipe body,
An annular bulge portion for retaining the outer end of the insertion end portion is provided, and the bulge portion is formed in a non-circular cross section.   The pipe connection structure according to claim 1, wherein the bulge part is formed in a cross-sectional shape having a flat cutout part in a circular part.   The pipe connection structure according to claim 1, wherein the bulge portion has a non-bulged portion at a plurality of locations in the circumferential direction and is formed in a non-circular cross section. A piping connection structure for connecting a resin tube for piping by tightly fitting it to the outer periphery of the insertion end of the pipe body,
On the outer periphery of the insertion end portion, an annular first bulge portion and a second bulge portion are provided at the distal end portion and the intermediate portion, respectively, and the first bulge portion is formed in a circular cross section, A pipe connection structure characterized in that the second bulge portion is formed in a non-circular cross section.

Images