Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L57/00—Protection of pipes or objects of similar shape against external or internal damage or wear
  • F16L57/06—Protection of pipes or objects of similar shape against external or internal damage or wear against wear
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04C—BRAIDING OR MANUFACTURE OF LACE, INCLUDING BOBBIN-NET OR CARBONISED LACE; BRAIDING MACHINES; BRAID; LACE
  • D04C1/00—Braid or lace, e.g. pillow-lace; Processes for the manufacture thereof
  • D04C1/02—Braid or lace, e.g. pillow-lace; Processes for the manufacture thereof made from particular materials

Definitions

• the present invention relates to a fabric sleeve for a rubber tube, especially for a rubber coupling fitted in a fluid circuit in a motor vehicle engine.
• It also relates to a process for manufacturing such a rubber tube surrounded by a fabric sleeve according to the invention.
• the conventional processes for manufacturing such reinforced tubes mainly comprise the extrusion of a rubber tubular substrate, the winding, overbraiding or overknitting of a fabric fibre on this substrate, and then the extrusion of a new rubber layer in order to embed the fabric reinforcement.
• Such an external protective sleeve is, for example, described in document US 5,366,771. It comprises a woven fabric, which mixes heat-recoverable yarns and heat-stable yarns, the fabric itself being embedded in polymer film. This fabric is manufactured in the form of a sheet and is would around the tube, the longitudinal edges then being fastened to each other in order to form a tubular sleeve around the tube.
• the object of the present invention is to propose a fabric sleeve which makes it possible, in particular, to simplify the way it is fitted onto a rubber tube and to make it easier to manufacture the rubber tube itself.
• the fabric sleeve for a rubber tube according to the invention is characterised in that it comprises heat-recoverable interlaced strands forming an elastically deformable tubular structure, the strands comprising at least one monofilament yarn and at least one multifilament yarn.
• this sleeve is tubular, its elastic structure makes it easier to fit onto the rubber tube, this structure allowing it to deform while it is being slipped onto the tube.
• the heat recovery of the strands allows the design of a sleeve which has a diameter greater than the external diameter of the tube, before recovery of the strands, and consequently is simpler to slip onto the tube.
• the tubular sleeve according to the invention is therefore perfectly adapted to being slipped onto rubber tubes of varied shape, and especially those having many bends.
• an external sleeve is obtained which allows both mechanical protection against abrasion of the rubber tube and reinforcement of the tube with respect to the internal pressure exerted by the fluids.
• the monofilament yarn allows the sleeve to be held elastically against the rubber tube, which thus develops a force sufficient to reinforce the tube with respect to the internal pressure.
• the monofilament yarn holds the multifilament yarn so as to bear on the rubber tube, thus increasing the ability of the multifilament yarn to protect the rubber tube from external attack and from the risk of wear.
• the fabric sleeve according to the invention also makes it possible to dispense with inserting a fabric reinforcement into the mass of rubber forming the tube. The manufacture of the latter is thus greatly simplified.
• the heat-recovery ratios of the monofilament yarn and of the multifilament yarn are approximately equal.
• the heat recovery of the fabric sleeve around the tube therefore takes place uniformly over all the strands, thereby avoiding the appearance of wrinkles on the surface of the sleeve, which would reduce its abrasion resistance and facilitate its deterioration.
• the recovery ratios are less than 40%, that is to say the difference in length of a yarn before and after heat recovery remains less than 40% of its initial length.
• the recovery ratio of the monofilament yarn is slightly greater than the recovery ratio of the multifilament yarn.
• This provision also prevents the formation of wrinkles on the surface of the fabric sleeve after recovery.
• the multifilament yarn being more compressible than the monofilament yarn, can absorb, by being compressed, a slight additional recovery of the sleeve caused by the monofilament yarn beyond its intrinsic recoverability.
• the strands are interlaced in the form of a flexible tubular braid, the diameter of the said braid increasing with the longitudinal compression of the said braid.
• the monofilament yarn is made of polyethylene terephthalate having great elasticity and the multifilament yarn is made of a high-tenacity polyamide.
• This composition of the fabric sleeve is well suited to its double function of reinforcing the tube with respect to the internal pressure and of mechanically protecting this tube.
• a process for manufacturing a rubber tube protected by a fabric sleeve according to the invention is characterised in that is comprises the following steps:
• This manufacturing process makes it possible to manufacture the rubber tube by continuous extrusion, unlike the conventional manufacturing processes which require successive extrusions in order to embed a fabric reinforcement in the rubber tube.
• the sleeve is recovered during the vulcanisation step at elevated temperature and consequently does not require an additional step compared with the conventional processes for manufacturing the rubber tubes.
• a rubber hose especially a coupling used in a fluid circuit of an engine, is characterised in that it is formed by a rubber tube covered by a fabric sleeve according to the invention.
• This rubber hose is thus externally reinforced with a fabric sleeve which perfectly matches its shape and creates no additional thickness, nor puckering, on its surface.
• FIG. 1 is a view illustrating a fabric sleeve according to the invention
• FIG. 2 is a perspective view of a rubber hose according to the invention.
• This fabric sleeve 1 is suitable for covering and protecting rubber hoses, such as couplings used in fluid circuits in motor vehicles, for example.
• This fabric sleeve 1 comprises heat-recoverable interlaced strands 2, 3, that is to say exhibiting heat-recoverability.
• This recoverability of each strand may be measured using a recovery ratio, corresponding to the maximum difference in length of the strand, before and after recovery, with respect to its initial length before heat recovery. Throughout the rest of the description, the recovery ratio corresponds to a recoverability measured in a dry oven at 200°C.
• the interlaced strands 2, 3 form an elastically deformable tubular structure.
• the strands 2, 3 are interlaced in the form of a flexible tubular braid, the diameter of the tubular braid increasing with the longitudinal compression of the braid.
• the fabric sleeve may be formed from knitted strands, the strands 2, 3 being knitted in the form of a flexible tubular knit, the diameter of the knit increasing with the longitudinal compression of the knit.
• the strands comprise a monofilament yarn 2 and a multifilament yarn 3.
• the heat-recovery ratios of the monofilament yarn 2 and of the multifilament yarn 3 are approximately equal, and remain less than 40%.
• the recovery ratios of the monofilament yarn 2 and of the multifilament yarn 3 are not equal, it is preferable for the recovery ratio of the monofilament yarn 2 to be slightly greater than the recovery ratio of the multifilament yarn, the latter being less sensitive to the formation of wrinkles since it is slightly compressible.
• the recovery ratio of the monofilament yarn 2 is between 1 times and 3 times the recovery ratio of the multifilament yarn 3, and preferably between 1.5 times and 2 times the recovery ratio of the multifilament yarn 3.
• the recovery ratio of the monofilament yarn 2 may be between 0.5 times and 4 times the recovery ratio of the multifilament yarn.
• the recovery ratio of the monofilament yarn 2 is between 3% and 40% and the recovery ratio of the multifilament yarn 3 is between 1% and 20%.
• the recovery ratio of the monofilament yarn 2 is between 5% and 30% and the recovery ratio of the multifilament yarn 3 is between 5% and 15%.
• the recovery ratio of the monofilament yarn 2 is between 15% and 25% and the recovery ratio of the mulifilament yarn is between 8% and 15%.
• the proportions of monofilament yarns and of multifilament yams in the fabric sleeve may vary over a wide range since the elasticity of the sleeve remains sufficient to allow easy fitting.
• the interlaced strands comprise between two monofilament yarns 2 per one multifilament yam 3 and one monofilament yarn 2 per ten multifilament yarns 3, and preferably between one monofilament yarn 2 per one multifilament yarn 3 and one monofilament yarn 2 per four multifilament yarns 3.
• the proportion is advantageously one monofilament yarn 2 per three multifilament yarns 3.
• a monofilament yarn with a very high modulus of elasticity will be present in a lower proportion than a monofilament yarn having a lower modulus, with respect to the total weight of the multifilament yarns employed.
• the monofilament yarn 2 used for its elasticity will preferably be made of polyethylene terephthalate.
• It may consist of any polymer having a high modulus of elasticity, such as olefin polymers, polyesters, polyphenylene oxides and sulphides, silicone-carbonate block copolymers, polyketones, polysulphones, polycarbonates, polyamides, epoxy resins and blends of these materials among themselves.
• the multifilament yarn 3 used for its abrasion resistance will preferably consist of a polyamide, such as a nylon-6 or a nylon-6,6. Any other type of polyamide polymer or of abrasion-resistant polymer may be chosen.
• This fabric sleeve 1 is fitted onto a rubber tube according to a manufacturing process illustrated in Figures 3A to 3E.
• a rubber tube 4 is extruded by a conventional extrusion technique.
• a cutting device 6 Downstream of the extruder 5, a cutting device 6 allows the rubber tube 4 to be cut to a predetermined length.
• the rubber tube 4 is preferably slipped onto a tubular mandrel 7.
• Figure 3C then illustrates the fitting of the fabric sleeve 1 on the tube 4, the diameter of the sleeve 1 being slightly greater than the diameter of the rubber tube 4.
• the rubber tube 4 fitted onto the mandrel 7 and covered by the fabric sleeve 1, is vulcanised as illustrated in Figure 3D, preferably in an autoclave oven 8.
• This vulcanisation causes heat recovery of the fabric sleeve 1, which thus perfectly matches the external surface of the rubber tube 4.
• the vulcanisation is preferably carried out at a temperature of approximately 180°C.
• the vulcanisation temperature depends, of course, on the type of rubber used for manufacturing the tube 4.
• the mandrel 7 is removed, as illustrated in Figure 3E, after the vulcanisation step.
• the recovery ratios of the strands making up the fabric sleeve 1 are not too high so that the heat-recovery force generated by the fabric sleeve 1 does not impede the operation of removing the mandrel.
• this protective sleeve 1 allow it to match the external surface of the tube 4 without puckering, nor areas of additional thickness, especially in the bent portions of the hose.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Textile Engineering (AREA)
• Rigid Pipes And Flexible Pipes (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)
• Laminated Bodies (AREA)
• Braiding, Manufacturing Of Bobbin-Net Or Lace, And Manufacturing Of Nets By Knotting (AREA)

Priority Applications (9)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9531335

Family Applications (1)

Country Status (14)

Cited By (2)

Families Citing this family (6)

Citations (6)

• 1998
  • 1998-10-08 FR FR9812618A patent/FR2784447B1/fr not_active Expired - Fee Related
• 1999
  • 1999-09-28 CA CA002346129A patent/CA2346129A1/en not_active Abandoned
  • 1999-09-28 BR BR9914327-5A patent/BR9914327A/pt not_active IP Right Cessation
  • 1999-09-28 PL PL99347065A patent/PL347065A1/xx unknown
  • 1999-09-28 AU AU60898/99A patent/AU6089899A/en not_active Abandoned
  • 1999-09-28 WO PCT/EP1999/007408 patent/WO2000022216A1/en not_active Application Discontinuation
  • 1999-09-28 EP EP99947468A patent/EP1119656A1/en not_active Withdrawn
  • 1999-09-28 HU HU0103757A patent/HUP0103757A2/hu unknown
  • 1999-09-28 CZ CZ20011267A patent/CZ20011267A3/cs unknown
  • 1999-09-28 SK SK469-2001A patent/SK4692001A3/sk unknown
  • 1999-09-28 ID IDW00200101011A patent/ID28401A/id unknown
  • 1999-09-28 JP JP2000576100A patent/JP2002527684A/ja active Pending
• 2001
  • 2001-04-03 BG BG105406A patent/BG105406A/bg unknown
  • 2001-04-04 ZA ZA200102757A patent/ZA200102757B/en unknown

Patent Citations (6)

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