FR2840847A1 - Production of pipe or conduit for circulating gaseous fluid(s) comprises providing tubular preform made of thermoplastic material loaded or not loaded with fibers - Google Patents

Abstract

Pipe or conduit (1) is produced by providing tubular preform made of thermoplastic material loaded or not loaded with fibers, arranging preform in open mold and insufflating expansion fluid under pressure into preform, closing the mold when the preform has reached a predetermined degree of radial expansion, extracting the unit from mold after solidification, and attaching or forming connecting and branching pieces at two opposing ends. Production of pipe or conduit comprises providing vibration attenuator in the form of a by-pass conduit portion opening at its two ends into pipe or conduit; providing tubular preform made of thermoplastic material loaded or not loaded with fibers; arranging preform in open mold and insufflating expansion fluid under pressure into the preform while its constituent material is still at a temperature close to its glass transition temperature or softening temperature; closing the mold when the preform has reached a predetermined degree of radial expansion to simultaneously form the walls (1', 2') of circulation pipe, by-pass conduit or pipe portion (2), and solid plate portions (3) connecting the pipe and the pipe portion to formed one piece with walls; extracting the unit (pipe/by-pass pipe portion) from the mold after solidification; and attaching or forming connecting and branching pieces at two opposing ends of the circulation pipe. An Independent claim is also included for a pipe or conduit for circulating gaseous fluid(s) comprising by-pass pipe portion(s) formed in one piece with the wall of circulation pipe and opening, and connecting piece at its two ends.

Description

area.

D E S C R I P T I O N

  The present invention relates to the field of means ensuring the circulation of gaseous fluids, and in particular the reduction of noise and vibrations linked to such circulation, and relates to a method of manufacturing a pipe provided with at least one attenuator. vibrations,

  S as well as a pipe obtained by such a process.

  I1 already exist many tubes, pipes or conduits comprising vibration attenuation devices, in particular acoustic. However, these attenuating devices are generally attached to the body of the pipe or conduit, thus requiring complex assembly operations, for example by vibration welding when

  said tube is made of a thermoplastic material.

  It has also been proposed to form the pipe with its attenuator by assembling several parts, each of them

  comprising a portion of the pipe and a portion of the attenuator.

  These two embodiments are particularly implemented

  for manufacturing pipes with attenuators in the form of portions of

branch pipe.

  The object of the present invention is in particular to propose a solution making it possible to obtain a hose with attenuator of the precise type in a simple manner, without assembly at its main constituent body and in particular not between the body of said hose and the body of said attenuator. For this purpose, the main object of the present invention is a method of manufacturing a pipe or conduit for circulation of gaseous fluid (s), provided with at least one vibration attenuator in the form of a portion of branch conduit. , opening at its two ends in said pipe or conduit, characterized in that it consists in providing a substantially tubular preform in thermoplastic material, loaded or not with fibers, in placing said preform in an open mold and in blowing under pressure a fluid expansion in this preform while its constituent material is still at a temperature close to its glass transition or softening temperature, to close the motile, when the preform has reached a predetermined degree of radial expansion, so as to - 2 simultaneously forming the walls of said circulation pipe and of the portion of duct or branch pipe, as well as portions of solid plates connecting the pipe and the portion of pipe and fo rmees in one piece with the walls of the latter, to be extracted from said mold [the assembly [circulation pipe / portion of pipe in derivation] after solidification and, finally, to add or form connection and connection ends to

  two opposite ends of the circulation pipe.

  The degree of expansion of the preform will depend on the form to be obtained and on the nature of the material used, said expansion being able to be completed at the time of the complete closure of the mold or possibly

still continue beyond.

  The portions of solid plates make it possible to stiffen the

  overall structure or to provide support and mounting plates.

  At least some of said portions may be provided with at least one through orifice, allowing the installation of a means of

  fixing of the stud, rivet or screw / nut type.

  The connection end pieces can be attached either by

  injection molding, either by vibration welding.

  These nozzles can each comprise one or more fixing eyelets form (s) integrally with said nozzles, to ensure the

  connection and assembly of the assembly at these ends.

  To make attenuations more efficient and more suited to the types of vibrations to be eliminated or reduced, provision may be made to provide the circulation pipe with at least one additional attenuator, intended to functionally cooperate with the first attenuator formed by

the bypass tube portion.

  Thus, according to a first embodiment of the invention, the method can consist in subsequently attaching at least one additional attenuator to said circulation pipe, for example by welding by

  vibrations at a hole in the wall of said pipe.

  According to a second preferred embodiment of the invention, making it possible to maintain a structure of the body of the circulation pipe without joint or similar assembly area, the method consists in forming at least one additional attenuator integrally with said pipe, by controlled conformation from the wall to said pipe when closing the

  mold on the preform expanded or still being expanded.

  - 3 In accordance with a very preferential variant of the invention, the circulation pipe is provided with two additional attenuators in the form of recesses with a circular cross section of its wall, located in the immediate vicinity, preferably following the openings of the ends. of the section of branch pipe in the form of

  loop leading into the circulation pipe.

  The present invention also relates to a pipe or conduit for the circulation of gaseous fluid (s) provided with at least one attenuator, obtained by the intermediary of the manufacturing process described above, characterized in that it comprises at least a portion of branched pipe, formed integrally with the wall of the circulation pipe and opening at its two ends into the latter, said circulation pipe being provided at each of its two ends with a connection connection piece or overmold, or form in one piece (depending on its

structural complexity).

  The invention will be better understood, thanks to the description below

  after, which relates to a preferred embodiment, given by way of nonlimiting example, and explains with reference to the accompanying schematic drawings, in which: Figure 1 is a front elevational view of the circulation pipe according to the invention ; Figure 2 is a top view of the pipe of Figure 1; Figure 3 is a right side elevational view of the pipe shown in Figure 2; Figure 4 is a sectional view along A-A of the pipe shown in Figure 2; Figure 5 is a sectional view along B-B of the pipe shown

in figure 2.

  The invention relates to a pipe or conduit 1 for the circulation of gaseous fluid (s) provided with at least one attenuation structure of

  vibrations, in particular acoustic, integrated.

  As shown in the figures of the appended drawings, said circulation pipe or duct 1 comprises at least one portion of branch pipe 2, formed integrally with the wall 1 'of the circulation pipe 1 and emerging at its two ends in the latter, said circulation pipe 1 being provided at each of its two ends with a connection end piece 4 attached or molded, or possibly in the form of a single

  holding with the circulation tube 1.

  Preferably, said circulation pipe 1 is provided with two additional attenuators 5 in the form of cavities or recesses set back from the wall 1 ′ of the circulation pipe 1, arranged after the

  2 "outlet portion of the branch pipe 2.

  The circulation pipe 1 may have a rectilinear structure (median axis of circulation in the form of a straight line) or not (median axis of circulation not rectilinear, but possibly located in a

1 0 plan).

  However, in general, said circulation pipe 1 will have a three-dimensional extension structure, adapting to the mounting site provided for its installation. In the latter case, the axes of the

  connection pieces 4 wind located in non-parallel planes.

  Figures 1 to 5 of the accompanying drawings show a mode of

  preferred embodiment of a circulation pipe according to the invention.

  This pipe or conduit 1 comprises a portion 2 of conduit or branched pipe in the form of a loop (attenuation by interference) and two lateral recesses 5 (attenuators in 1/4) forming cavities in the wall 1 'of the pipe 1 substantially in look of the through openings 2 "of the bypass portion 2. This gives a complex attenuator structure in the form of A. As shown in the figures of the accompanying drawings, the axes of symmetry of the circular recesses 5 are inclined with respect to the axes 2 "openings at the ends of the pipe portion

derivation 2.

  This pipe or duct assembly 1 / loop portion 2 is remarkable in that its main body is obtained in a single injection-blowing manufacturing operation, therefore in a continuous manner (absence of

joint, or assembly line).

  It has, at its opposite ends, connection or connection ends 4. These latter, for example, are reported

by vibration welding.

  Preferably, the pipe or conduit l with its attenuators 2 and 5 is produced in PA6 or PA66 loaded at 15% with glass fibers and the end pieces 4, as well as the various pastes or fins 4 'for fixing, wind in PA6

  or PA66 3 to 5% glass fiber filler.

  However, the circulation pipe 1 / attenuators 2, 5 assembly may also be made of an unloaded thermoplastic material, metal rings then being placed and overmolded at the level

connection fittings 4.

  S Said assembly will find an advantageous use in relation to the circulation of hot gases under pressure, such as for example downstream

  or at the outlet of a motor vehicle turbocharger.

  Of course, the invention is not limited to the embodiment described and shown in the accompanying drawings. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without leaving for

  as much of the protection field of the invention.

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Claims (10)

  1. Method for manufacturing a pipe or pipe for circulation of gaseous fluid (s), provided with at least one vibration attenuator in the form of a portion of branch pipe, opening at both ends in said pipe or conduit, characterized in that it consists in providing a substantially tubular preform made of thermoplastic material, loaded or not with fibers, to dispose said preform in an open mold and to inject under pressure an expansion fluid in this preform while its material constitutive is still at a temperature close to its glass transition or softening temperature, to close the motile, when the preform has reached a predetermined degree of radial expansion, so as to simultaneously form the walls (1 'and 2') at said circulation pipe (1) and the portion of duct or branch pipe (2), as well as portions of solid plates (3) connecting the pipe (1) and the portion of pipe (2) and formed of a standing alone with walls (1 'and 2') of the latter, to be extracted from said mold ['assembly [pipe (l) / portion of branch pipe (2)] after solidification and, finally, to add or form end pieces (4) of connection and connection at the two opposite ends of the circulation pipe (1).   2. Method according to claim 1, characterized in that at least some of the solid plate portions (3) are provided with at least a through hole (3 ').   3. Method according to claim 1 or claim 2, characterized in that the connection end pieces (4) are reported by injection molding.   4. Method according to claim l or claim 2, characterized in that the connection end pieces (4) are reported by vibration welding.   5. Method according to any one of claims 1 to 4,   characterized in that the connection end pieces (4) each comprise one or more fixing eyelets (4 ') in the form of a senl holding with said end caps (4).   6. Method according to any one of claims 1 to 5,   characterized in that it consists in subsequently attaching at least one additional attenuator (5) to said pipe (1), for example by welding -7 by vibration at the level of a hole in the wall (1 ') to said pipe ( 1)   7. Method according to any one of claims 1 to 6,   characterized in that it consists in forming at least one additional attenuator (S) integrally with said pipe (1), by controlled conformation of the wall (1 ') to said pipe (1) when the mold is closed on the   preform expanded or still expanding.   8. Method according to any one of claims 6 or 7,   characterized in that the circulation pipe (1) is provided with two additional attenuators (5) in the form of recesses with circular section of its wall (1 '), located after the openings (2 ") of the ends of the portion of branch pipe (2) in the form of a loop opening into the circulation pipe (1).   9. Pipe or conduit for circulation of gaseous fluid (s) provided with at least one attenuator, obtained by means of the method of   manufacture according to any one of claims 1 to 8, characterized in   that it comprises at least a portion of branch pipe (2), forms a senl holding with the wall (1 ') of the circulation pipe (1) and opening at its two ends into the latter, said pipe circulation (1) being provided at each of its two ends with a connection end piece (4) reports or molds.   10. Pipe according to claim 9, characterized in that it is provided with two additional attenuators (5) in the form of cavities or recesses recessed from the wall (1 ') of the circulation pipe (1), arranged at the continuation of the outlet openings (2 ") of the branch pipe portion (2) and in that the axes of the connection end pieces (4) are located in planes