DE102008059795B4 - Method for producing a pressure hose by injection molding - Google Patents

Abstract

Method (10) for producing a pressure hose (12) with the following steps: - injection molding (14) of a tubular first hose element (16), - pulling (28) a fabric hose (30) on the outside of the first hose element (16), - injection molding ( 32) of a tubular second hose member (34) around the first hose member (16) and the fabric hose (16) drawn thereabove.

Description

Background of the invention

The invention relates to a method for producing a pressure hose.

Pressure hoses are used in particular in the field of motor vehicles, for example on turbochargers. But especially in the field of household and commercial cleaning machines, such as dishwashers and washing machines, pressure hoses are used. The production of such pressure hoses is relatively expensive. In known pressure hoses an inner layer or an inner tube is first extruded, which is subsequently wrapped with a fabric strip. In a second extrusion step, an outer layer is extruded onto the inner tube wound in this way. Thereafter, the extruded tube is cut into pieces which are pulled individually onto a core. On the core of each tube section is annealed and thus receives its final shape.

Out DE 42 30 946 A1 For example, a method for producing a pressure hose is known. According to this method, a tubular inner coating is produced by injection molding or extrusion. In a subsequent weaving process, this inner coating is woven in by adding warp and weft. Before the weaving process, the inner coating is pre-vulcanised and vulcanised after the weaving process has finished. To maintain its geometry, the hose is pulled off by a caterpillar take-off.

Out EP 1 160 496 A1 For example, a fuel hose is known in which inter alia an inner layer and an outer layer are produced by means of injection molding.

Underlying task

The invention has for its object to make the production of such pressure hoses more cost effective.

Inventive solution

This object is achieved according to the invention with a method for producing a pressure hose according to claim 1. Advantageous developments are described in the dependent claims.

According to the invention, a method for producing a pressure hose is provided with the following steps: injection molding of a tubular first hose element, pulling a fabric hose outside onto the first hose element and injection molding a tubular second hose element around the first hose element and the fabric hose pulled over it.

In other words, according to the invention, a pressure hose is produced in that a first inner tube is produced by means of a first injection molding process, subsequently a reinforcing stocking or fabric tube is pulled onto the inner layer and finally the inner layer with the reinforcing stocking is overmoulded with an outer layer in a second injection molding process , The outer layer forms the said second tubular element, which in this way is integrally connected to the first tubular element and the fabric tube. The fabric tube is embedded between the two tube elements, wherein the material of the second tube element penetrates the tissue of the fabric tube and connects directly to the material of the first tube member.

The method according to the invention is more cost-effective and leads to particularly individually adaptable and therefore also particularly resistant pressure hoses which, moreover, also allow particularly many variants and design options in their remaining shape.

Advantageous developments of the invention

In a first advantageous development of the invention, the step is further provided: cutting the wound fabric hose on at least one of its end sections. The cutting of the fabric tube after the step of being pulled onto the first tubular element allows the braided tube to be cut slightly shorter than the associated tubular element if necessary. It is thereby prevented that fringes of the fabric hose protrude from the finished pressure hose, as is well known in known pressure hoses. Furthermore, according to the invention, the end sections of the fabric hose can be specially embedded, in particular by forming special shapes or geometries at the end sections of the first hose element.

In a second advantageous development of the invention, at least one connection element is injection-molded onto an end region of the pressure hose in the step of injection-molding the first and / or the second hose element. The connection element is particularly preferably a flange or a sealing edge for the pressure-tight attachment of the finished pressure hose to a further technical component.

In a third advantageous development of the invention, at least one connection element is injection-molded onto a section of the wall of the pressure hose in the step of injection molding of the second hose element. In other words, in this development, connecting flanges, support surfaces or the like are formed on the outside of the pressure hose at its longitudinal extent. Such elements facilitate a later attachment of the pressure hose to an associated technical component and can be produced according to the invention almost cost neutral.

In a fourth advantageous embodiment of the invention, a thermoplastic elastomer is processed during injection molding.

In a fifth advantageous embodiment of the invention, a hose made of aramid is processed as a fabric hose. Aramids or aromatic polyamides (polyaramides) are those long-chain synthetic polyamides in which at least 85% of the amide groups are bonded directly to two aromatic rings. Aramid is produced as a fiber for the fabric hoses used according to the invention. The fibers are characterized by very high strength, high impact strength, high elongation at break, good vibration damping and resistance to acids and alkalis. They are also very heat and fire resistant. Aramid fibers do not melt at high temperatures, but begin to char from about 400 ° C.

In a sixth advantageous development of the invention, the pressure hose is molded onto a core during the injection molding of the first and second hose element and subsequently demoulded from this core by means of a pressure pulse.

In a seventh advantageous development of the solution according to the invention, the pressure hose during injection molding of the first and / or second hose member is formed with partially different wall thicknesses and / or materials depending on the acoustic requirements to be met. Modern machines and plants, which use pressure hoses, are subject to increasingly stringent acoustic requirements. "Pollution" from noise is an increasingly important topic. According to the invention, these acoustic requirements can be met in a particularly simple manner by determining areas with wall thicknesses of different thicknesses and / or different rigid materials by empirical investigations and / or calculations and subsequently forming them very inexpensively with the injection molding method according to the invention.

An eighth advantageous development of the invention comprises the step: encapsulation of a connection region of a component to which the pressure hose to be produced is to be coupled in a fluid-tight manner during the step of injection molding the tubular first and / or second hose element. With such spraying can be dispensed with a separately to be mounted and sealed connection from the pressure hose to another component. It not only eliminates an assembly step, but it can also be minimized in particular the risk of leakage at the junction between the inventive pressure hose and coupling component. The injection of the pressure hose to the component can be done from the outside or particularly advantageous from the inside against the wall of the component. It is then pressed under pressure from the pressure hose from the inside against the wall of the component and a principle possible removal of the pressure hose from the component additionally prevented.

In a ninth advantageous development of the solution according to the invention, the component is inserted with its connection area during injection molding of the first and / or second tubular element as an insert in an associated injection mold and supported / the core for molding the first tubular element on this insert.

Brief description of the drawings

Hereinafter, an embodiment of the solution according to the invention will be explained in more detail with reference to the accompanying drawings. It shows:

1 a flowchart of an embodiment of the method according to the invention,

2 a partially sectioned view of one with the method according to 1 manufactured pressure hose,

three a variant of the first method step according to 1 and

4 a variant of the third method step according to 1 ,

Detailed description of the embodiment

In the 1 is a procedure 10 for making a pressure hose 12 which illustrates injection molding as the first essential step 14 a tubular first hose member 16 on a core, here in the form of an insert core 18 , includes. The insert core 18 is in one of two halves 20 and 22 formed first injection mold 24 into which a thermoplastic elastomer 26 injected under high pressure and high temperature.

The following will be in one step 28 a fabric hose made of aramid 30 on the outside of the first hose element 16 mounted or mounted. The first hose element 16 is still on the insert core 18 which has been previously removed only from the first injection mold. Further, in the step 28 the fabric hose 30 cut at its two end faces so that it does not or only slightly over the associated ends of the first tubular element 16 protrudes.

In a subsequent step 32 becomes a tubular second hose element 34 around the first hose element 16 and the fabric tube pulled over it 30 injection molded. The insert core 18 is located together with the first hose element 16 and the suspended fabric hose 30 in a turn of two halves 36 and 38 formed second injection mold 40 , wherein a second, optionally of the thermoplastic elastomer 26 distinctive second thermoplastic elastomer 42 in the injection mold 40 is injected. In this second injection molding process are on the pressure hose 12 at the same time two end flanges 44 and 46 designed as connection elements. Furthermore, a cable clip 48 as a connection element on the wall of the pressure hose 12 with a metallic insert disposed therein 50 educated.

Alternatively or additionally, in a non-illustrated embodiment of a pressure hose 12 also one or more bellows are formed. Also, different wall thicknesses can be realized in sections of different proportions of material, in particular to optimize the mobility of the pressure hose with simultaneous pressure resistance.

In this case, areas of different wall thicknesses and / or materials can also be formed particularly advantageously as a function of acoustical requirements to be met.

In a final operation, the pressure hose 12 including the insert core 18 from the second injection mold 40 taken and subsequently by means of an air-pressure pulse from the insert core 18 removed from the mold.

In three is a variant of the method step 14 according to 1 illustrated in which the first hose member 16 in injection molding not only on the insert core 18 but at one of its end regions at the same time from the outside to a connection area 52 another component 54 is sprayed on. The component 54 is here as an insert in the from the two halves 20 and 22 formed injection mold 24 , wherein the insert core 18 at its associated end region inside the connection area 52 is supported.

In 4 is a variant of the process step 32 according to 1 shown in which the second hose element 34 not only on the outside of the first hose element during injection molding 16 and the fabric hose 30 is injected, but at the same time from the inside against a connection area 52 another component 54 , The component 54 is also in the injection mold 24 inserted and the insert core 18 supported inside. The component 54 points in the connection area 52 inside on its wall several annular (unspecified) formations, in the material 56 of the second hose element 34 in injection molding 32 penetrates to form a positive connection between the pressure hose in this way 12 and the component 54 manufacture.

LIST OF REFERENCE NUMBERS

10

method

12

pressure hose

14

Injection molding of the first hose element

16

first hose element

18

insert core

20

half

22

half

24

first injection mold

26

first thermoplastic elastomer

28

Pulling on the fabric hose

30

Gewebeschlauch

32

Injection molding of the second hose element

34

second hose element

36

half

38

half

40

second injection mold

42

second thermoplastic elastomer

44

Flange as connecting element

46

Flange as connecting element

48

Cable clip as connection element

50

insert

52

terminal area

54

component

56

Material of the second hose element

Claims (10)

Procedure ( 10 ) for producing a pressure hose ( 12 ) comprising the steps of: - injection molding ( 14 ) of a tubular first tubular element ( 16 ), - mounting ( 28 ) of a fabric hose ( 30 ) on the outside of the first hose element ( 16 ), - injection molding ( 32 ) of a tubular second hose element ( 34 ) around the first one Hose element ( 16 ) and the fabric tube ( 16 ). Method according to claim 1, comprising the step of: cutting the wound up fabric tube ( 30 ) at least one of its end sections after step ( 28 ) of the winding up of the fabric hose ( 30 ) on the outside of the first hose element ( 16 ). Method according to Claim 1 or 2, with the step: injection molding of at least one connecting element ( 44 . 46 ) at one end region of the pressure hose ( 12 ) at the injection molding step ( 14 ; 32 ) of the first and / or the second tubular element ( 16 ; 34 ). Method according to one of claims 1 to 3, with the step: injecting at least one connection element ( 48 ) at a portion of the wall of the pressure hose ( 12 ) at the injection molding step ( 32 ) of the second hose element ( 34 ). Method according to one of claims 1 to 4, wherein in injection molding ( 14 . 32 ) a thermoplastic elastomer ( 26 . 42 ) is processed. Method according to one of claims 1 to 5, wherein as a fabric hose ( 30 ) a hose made of aramid is processed. Method according to one of claims 1 to 6, wherein the pressure hose ( 12 ) in injection molding ( 14 ; 32 ) of the first and second tubular elements ( 16 ; 34 ) on a core ( 18 ) and subsequently from this core ( 18 ) is removed from the mold by means of a pressure pulse. Method according to one of claims 1 to 7, wherein the pressure hose ( 12 ) in injection molding ( 14 ; 32 ) of the first and / or second tubular element ( 16 ; 34 ) is formed with partially different wall thicknesses and / or materials depending on the acoustic requirements to be met. Method according to one of claims 1 to 8, comprising the step of: overmolding a connection region ( 52 ) of a component ( 54 ), to which the pressure hose ( 12 ) is to be coupled fluid-tight, in the step of injection molding ( 14 ; 32 ) of the tubular first and / or second tubular element ( 16 ; 34 ). Method according to Claim 9, in which the component ( 54 ) with its connection area ( 52 ) in injection molding ( 14 ; 32 ) of the first and / or second tubular element ( 16 ; 34 ) as an insert in an associated injection mold ( 24 ; 40 ) and a core ( 18 ) for molding the first tubular element ( 16 ) is supported on this insert.

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