EP1182672B1 - Method to manufacture a dimensionally stable cable-harness and foaming tool for manufacturing such a cable-harness - Google Patents

Abstract

The method involves laying individual cables (22) in a hollow chamber (8) of a foam tool (2), which has an upper part (6) and a lower part (4). A vacuum is established between the upper and lower parts and the individual cables are enclosed in foam by introducing a material capable of forming a foam into the chamber. Independent claims are also included for the following: a foam tool for an especially stable shape cable set.

Description

The invention relates to a method for producing a particularly dimensionally stable Cable set and a foaming tool for performing such Process.

A dimensionally stable cable set (FSK) is generally a cable set, i.e. one Summary of individual cables, understood which is dimensionally stable in one given geometry. For the production of the dimensionally stable cable set are the individual cables usually in a special form, the so-called Foaming tool, inserted and with an initially available in liquid form foamable material. PU foam is preferred used. Such a dimensionally stable cable set is used in particular in automotive engineering used and serves as a prefabricated unit for laying of electrical lines within the motor vehicle. That by construction of the motor vehicle predetermined geometric boundary conditions, that is Space and predetermined routes for the cable set are given in the Manufacturing considered as a dimensionally stable unit. Such a cable set is known for example from GB 2 160 028.

Due to the foaming, compressive forces are exerted on the foaming tool. This must therefore exert a counter pressure in order to avoid the Foaming tool to be able to impress the cable set, and to prevent foam from leaking out of the mold. A conventional one Foaming tool therefore has a solid base and Upper part, which is pressed together using complex hydraulic technology become. Because of the large forces that the foaming tool can withstand , the upper part and the lower part must be solid and heavy.

The invention is based on the problem of simple manufacture of a particular to enable dimensionally stable cable set.

According to the invention to achieve this object in a method for manufacturing an in particular dimensionally stable cable set with a number of individual cables in a cavity of a foaming tool, which has an upper part and a Lower part includes the number of individual cables inserted between the lower part and the upper part creates a negative pressure and a foamable in the cavity Material introduced so that the individual cables are foamed.

This version is based on the idea instead of using external pressure forces the two parts of the foaming tool using vacuum (vacuum) to press against each other. A decisive advantage is that that on the one hand the complex and expensive hydraulic technology is eliminated, and that on the other hand, the foaming tool is significantly simpler and, in particular, lighter is designed. In particular, it is possible to replace what was previously necessary Metal tool to use for example a plastic tool perform at least one of the two parts made of plastic.

In this case, the negative pressure is preferably set within the cavity. According to a preferred development, the vacuum is additional or alternative applied in the area adjacent to the cavity between the two parts. For this purpose, a vacuum chamber is provided, in which the vacuum is generated can be. This ensures that those flanking the cavity Areas of the upper and lower parts are pressed tightly together.

Vacuum channels running along the cavity are preferred as the vacuum space provided so that the two tool parts (upper part and lower part) along the generally elongated cavity securely and firmly to each other be pressed.

According to an expedient development, in the cavity and in the vacuum chamber different negative pressures are set, especially in the cavity a lower vacuum is set than in the vacuum room. So that will ensures that the cavity keeps its desired shape and not because of too high a vacuum is deformed. At the same time there is the possibility to set a very high vacuum in the vacuum chamber, the one ensures firm pressing of the two tool parts, so that these lie close together. So-called webbeds are largely used avoided. These webs are formed by the fact that when foaming a certain proportion of the foamable material in the sealing surface between the two tool parts is pressed. These webbeds, also called film skins referred to, have to be done in complex and costly post-processing steps usually be removed again.

For the same purpose, namely to prevent the formation of the webbed skin, are preferably in different sub-areas of the vacuum chamber different negative pressures set. The vacuum space is therefore in different subdivisions. Both in these subspaces of the vacuum room as well as in the cavity itself, the negative pressure values can be set independently of one another. The main advantage of the separated sub-rooms is that in areas where Webs occur, a higher negative pressure can be applied, to increase the contact pressure of the two tool parts against each other. It will So the contact pressure between the upper part and the lower part increases there, where webbed skin occurs. The vacuum channels running on both sides of the cavity are such sub-areas. Are now in these vacuum channels different negative pressures are set, so the two tool parts more compressed on one side than on the other. This will quasi a slight "tilting" of the upper part relative to the lower part parallel alignment.

The negative pressure is advantageously applied during the filling of the foaming tool controlled in the cavity to prevent deformation of the cavity on the one hand and on the other hand, to prevent the occurrence of air bubbles. In particular, too Start of the process when the foamable material is first introduced is set, no or only a slight negative pressure in the cavity. With increasing The foam traps the air trapped in the cavity displaced and there is a risk that air bubbles occur. Here is the Pressure in the cavity is monitored during the process and, for example, on one held certain value. The air compressed by the foaming becomes quasi deducted to prevent the appearance of air bubbles.

According to a further preferred embodiment there is an opening in the foaming tool towards the cavity when a pressure value in the cavity is exceeded automatically closed to prevent foam from escaping.

The object is further achieved by a foaming tool for a particularly stable cable set, with a lower part and with a Upper part, which in the assembled state has a cavity that can be filled with foamable material for insertion form a number of individual cables of the cable set, wherein between the Upper part and the lower part is provided with a negative pressure by a suitable means.

The advantages and preferred embodiments mentioned with regard to the method are to be transferred accordingly to the foaming tool.

According to a preferred development, the foaming tool has a number provided by side-by-side vacuum channels. Thereby it is achieved on the one hand that the two tool parts have a comparative large area are pressed against each other. Since each of the vacuum channels has a quasi-sealing effect due to the fact that several are arranged next to each other Vacuum channels achieved a kind of sealing cascade.

In order to obtain the best possible seal, this is preferred The upper part and the lower part in the manner of the tongue and groove principle. Are there preferably again several tongue and groove seals lying next to each other intended.

For the same purpose of better sealing is preferably immediately on Cavity adjacent between the upper part and the lower part a sealing element provided, which is designed in particular as a separate element and preferably consists of a special sealing material, for example rubber.

Further preferred embodiments of the foaming tool are the subclaims refer to.

Fig. 1

einen Querschnitt durch ein Schäumwerkzeug,

Fig. 2

eine Aufsicht auf ein Oberteil eines Schäumwerkzeugs,

Fig. 3 bis 5

unterschiedliche Varianten von Abdichtungsmöglichkeiten für ein Entlüftungsloch und/oder einen Einfüllstutzen,

Fig. 6

eine Querschnittsansicht eines Austrittbereichs aus dem Schäumwerkzeug mit einer Austrittsdichtung, und

Fig. 7 bis 10

unterschiedliche Varianten für die Austrittsdichtung.

Exemplary embodiments of the invention and further preferred refinements of the foaming tool are explained in more detail below with reference to the figures. Each shows in schematic representations:

Fig. 1

a cross section through a foaming tool,

Fig. 2

a top view of an upper part of a foaming tool,

3 to 5

different variants of sealing options for a ventilation hole and / or a filler neck,

Fig. 6

a cross-sectional view of an exit region from the foaming tool with an exit seal, and

7 to 10

different versions for the outlet seal.

1 has a lower part 4 and an upper part 6, the enclose a cavity 8 in the assembled state. The upper part 6 has an opening 10 to the cavity 8. About the opening 10 there is Possibility to create a vacuum (vacuum) in the cavity 8. The opening 10 can also be used as a filling opening for a foamable material (PU foam) or serve as a vent.

The upper part 6 and the lower part 4 are each contoured so that they interlock according to the tongue and groove principle. On the left half of the picture is this by means of a crenellated design of the upper part 6 with first crenellations 12A and a second battlement 12B, which has an angular cross-sectional geometry exhibit. On the right half of the picture is an alternative embodiment to the lower part 4 rounded spring 14 is provided. The battlements 12A, 12B and the spring 14 are dimensioned such that between the upper part and the lower part on both sides of the cavity 8 vacuum channels 16 as a vacuum space are formed. Suction connections each lead to these vacuum channels 16 18, to which a vacuum pump can be connected to in the vacuum channels 16 to create a vacuum.

The battlements 12A, 12B and the spring 14, in addition to the formation of the vacuum channels 16 also a good positioning or self-adjustment of the two parts to each other. In addition, the crenel 12B, which connects directly to the cavity 8, a sealing function between the Upper part 6 and the lower part 4 against emerging foam true. alternative to the configuration with the permanently molded battlement 12B can be used for sealing a separate sealing element 20 can also be provided, which - as in the right one Half of the picture shown - is preferably wedge-shaped. The sealing element consists preferably of a different material than the foaming tool 2, for example made of a silicone sealing material.

The seal is used in particular to avoid so-called film or Webbed. These form when a foamable material, which is introduced into the cavity 8, in the sealing gap between the upper part 6 and Lower part 4 arrives. Such webs are undesirable and require one complex and costly post-processing. An essential criterion for Avoiding the webbed skin is to press the lower part together 4 to the upper part 6. The contact pressure of the two parts 4.6 against each other Significantly adjusted by the level of the vacuum in the vacuum channels 16. For a particularly good seal are therefore preferably - as in the shown on the left half of the image - a plurality of vacuum channels 16 arranged side by side, in order to be able to increase the contact pressure on the one hand and on the other hand to be able to apply the contact pressure over a larger local area. 1, left half of the image, two vacuum channels 16 are provided, each are formed between two battlements 12A, 12B. This configuration is realized a kind of cascade of seals.

To create a dimensionally stable cable set, a Number of individual cables 22 inserted, then 8 is inserted into the cavity Foamed material not shown filled. The foamable material then foams inside the cavity 8 and takes the from Cavity 8 predetermined shape. By applying a vacuum in the cavity 8 and / or in the lateral vacuum channels 16, the two parts 4.6 held against each other and pressing these two parts together 4.6 from the outside using complex hydraulic technology is not necessary. Prefers becomes a higher vacuum in the lateral vacuum channels 16 than in the cavity 8 designed to achieve a sufficiently high pressing force on the one hand, and on the other hand to prevent the cavity 8 from being too high Vacuum is deformed.

The foaming tool 2 preferably consists of an easy to manufacture Hard plastic with glass fiber reinforcement or possibly with inserted metal struts. The tool only needs feet to be in the correct position to be filled. A flat contact surface is not necessary. Let it through save the weight and the curing time. The material of the foaming tool 2, in particular that of the lower part 4, is hard and has one the lowest possible thermal expansion. In contrast, the upper part 6 is elastic trained to ensure an adequate sealing function. simultaneously the upper part 6 has sufficient inherent rigidity to be applied Negative pressure not to be pulled inwards. To the rigidity too aim, stiffeners are preferably provided, in particular the Grasp the foaming tool.

The upper part 6 is preferably made of a transparent one, at least for experimental purposes Plastic trained. This allows when trying out a new one Foaming tool 2 to follow the foaming process. Thereby the possibility is created to see where directly when frothing For example, air bubbles form and, therefore, where best ventilation openings be attached.

Since no complex external hydraulic technology is still necessary, it offers also, the entire foaming tool 2, for example, somewhat obliquely so that there are air bubbles - if they exist at all due to the negative pressure arise - form at a predefined location. In particular, is on the top Area of the cavity 8 created a way to vent.

It is preferred to prevent air bubbles during the foaming process the vacuum in cavity 8 is controlled and changed, so that always there is sufficient negative pressure. This has the advantage of beginning the foaming process in the cavity 8 initially little or no Vacuum must be present. This causes the cavity 8 to deform a too high negative pressure excluded. The necessary contact pressure between the upper part 6 and the lower part 4 are therefore decisive the vacuum in the side vacuum channels 16 caused.

The use of a transparent upper part 6 enables monitoring on Formation of air bubbles and thus the appropriate setting of the negative pressure in cavity 8. Monitoring for the formation of the Air bubbles automatically. Optical methods are used in particular for this purpose. There is also the option of using ultrasound methods. The automatic monitoring preferably also enables automatic monitoring Control or regulation of the vacuum conditions, especially in the Cavity 8.

Due to the low weight there is also the possibility to avoid to let air bubbles vibrate the foam tool 2 as a whole, to "shake" any air bubbles that may arise out of the foamable material.

From the top view of the upper part 6 of the foaming tool 2 according to FIG To recognize filler neck 24. Above this, which is also known as a sprue the foamable material is filled in. There are also several Set vent holes 26 indicated.

The course of the cavity 8 within the foaming tool 2 is shown by dashed lines Lines and that of the side vacuum channels 16 by dotted lines shown. The course of the lateral vacuum channels 16 preferably follows in essentially the course of the cavity 8. The lateral vacuum channels 16 are divided into a number of subspaces 27. This is in FIG. 2 by hyphens indicated in the vacuum channels 16. The negative pressures shown in the two Vacuum channels 16 and in the individual subspaces 27 are from one another preferably independently and essentially arbitrarily adjustable. Thereby the possibility is created to suitably adjust the contact pressure locally, in particular to increase, for example, the training of Avoid webbed skin.

The individual cables 22 are made on the end sides 28 of the foaming tool 2 this led out. The corresponding outlet openings are with the help of Outlet seals 30 sealed to prevent foam from escaping.

In order for foam to escape from the vent holes 26 and / or the To prevent filler neck 24, valves 31 are preferably provided. different Variants of the valves are shown in FIGS. 3 to 5.

• Das Schäumwerkzeug 2 ist vergleichsweise billig, es ist kein Druck-Schließsystem notwendig.
• Aufgrund der dichtenden Ausbildung des Unterteils 4 und des Oberteils 6 nach Art eines Nut-Feder-Prinzips ist die Ausbildung von Filmhäuten zwischen diesen beiden Teilen 4,6 verhindert.
• Durch den Unterdruck ist das Auftreten von Luftblasen verhindert oder zumindest reduziert. Zudem lässt sich das Auftreten von Luftblasen im Versuchsstadium einfach während des Schäumungsprozesses beobachten.

With such a foaming tool 2, the following advantages in particular are achieved compared to a conventional foaming tool:

• The foaming tool 2 is comparatively cheap, no pressure locking system is necessary.
• Due to the sealing design of the lower part 4 and the upper part 6 in the manner of a tongue and groove principle, the formation of film skins between these two parts 4, 6 is prevented.
• The occurrence of air bubbles is prevented or at least reduced by the negative pressure. In addition, the occurrence of air bubbles in the experimental stage can be easily observed during the foaming process.

3 and 4, the valve 31 is formed by a seen in cross section approximately cruciform design of the cavity 8, wherein a sealing element 32 is arranged. According to FIG. 3, the sealing element 32 is curved Element formed that extends into the lateral openings 34 of the cruciform Cavity 8 extends into it. The curvature is preferably for Top 36 oriented, from which the cavity 8 with the foamable material is filled. When filling, there is therefore the possibility for this material on the sealing element 32 to flow along and into the lower region 38 of the cavity 8 to arrive. If the material foams, the sealing element 32 shifted upwards and against the upper boundary edges 40 of the side Openings 38 pressed. The boundary edges 40 act as a sealing seat. The negative pressure prevailing in the cavity 8 supports the fact that the Air 8 in the cavity emerges through the opening 10 during the foaming process can, and that the sealing member 32 due to the foaming in Cavity 8 resulting air cushion not already against the upper boundary edges 40 is pressed.

4 is a instead of the curved sealing element 32 of FIG. 3 Sealing element 32 is provided with a circular cross section. The principle of action is similar to the sealing element 32 according to FIG. 3. When foaming this sealing element 32 with the circular cross section is also counter the boundary edges 40 are pressed to allow the foam to exit the opening 10 to prevent.

5, the valve 31 is in a further variant in the manner of a cut Sparkling wine cork. Such "champagne cork seals" are simple to manufacture and therefore also very inexpensive. You can go beyond that can be quickly attached to the foaming tool 2. It therefore lends itself to a to provide such valve 31 as a one-way valve or as a one-way seal. It has an upper hollow cylindrical region 42, which adjoins it Bottom connects a closure flap 44 in the manner of a check valve. This valve 31 shown in FIG. 5 can in particular be self-sealing Filler neck 24 are used and as such is in an opening 10 introduced in the foaming tool 2. For a secure fit in one The opening has the upper hollow cylindrical region 42 with barbs 46. The foamable material is through the interior of the hollow cylindrical area 42 cast in and can penetrate into the cavity 8 on the lower side, because the flap 44 is folded down. Foams the material in the cavity 8, it presses against the flap 44 and this is pivoted upwards and against one at the lower end of the hollow cylindrical Area 42 arranged sealing seat 48 pressed. With the in Figs. 3-5 shown valves 31 prevents leakage of foam and at the same time the negative pressure is effective up to the highest filling point.

6 is a cross section through the outlet seal 30 with those enclosed by it Individual cables 22 shown. The outlet seal 30 has one ring-like outer seal carrier 50 made in particular of a hard and rigid Material on. On the inside, oriented to the individual cables 22, is on Seal carrier 50 arranged a seal part 52 which can be pressed onto the individual cables 22. The outlet seal 30 is in two separable halves 53A, B divided.

7 to 10 different versions of the outlet seal 30 are shown. Common to all is the rigid seal carrier 50 to which the actual one Sealing part 52 is arranged. The rigid seal carrier 50 according to FIG. 10 has wires 54 running on both sides, ie is wire-reinforced. Between A soft material can be clamped on the two wires according to the type of Food packaging usual closure means, in which between the Wires for example paper or thin plastic films are stretched. The Sealing part 52 is made, for example, as a soft, elastic sealing part Rubber or silicone formed, as indicated in FIGS. 7 and 10. Here, the sealing part 52 consists of solid material. In contrast, that closes Sealing part 52 according to FIGS. 8 and 9 a hollow interior 56. The 9 is made of a hard elastic material. With regard to the sealing part 52 shown in FIG. 8, the To apply interior pressure 56 with overpressure, so that the sealing part 52 against the individual cables 22 are pressed in order to securely seal them.

The special structural design of the foaming tool 2 is in principle generally applicable to molds in which a cavity 8 is pressed against each other is formed by molded parts, and in this cavity forming material is introduced. Such a molding tool is suitable therefore for a variety of molding processes in which the mold halves must be pressed together. The key advantage is that none external pressure must be applied. The molding tool is particularly suitable therefore for so-called large molded parts, which, for example, spread length of more than 0.5 m.

LIST OF REFERENCE NUMBERS

2

foaming

4

lower part

6

top

8th

cavity

10

opening

12A, B

battlements

14

feather

16

Vacuum channel

18

suction

20

sealing element

22

Single cable

24

filler pipe

26

vent hole

27

subspaces

28

end side

30

outlet seal

32

sealing

34

lateral. opening

36

top

38

lower area

40

boundary edge

42

hollow cylindrical area

44

cap

46

barb

48

sealing seat

50

seal carrier

52

sealing part

53A, B

separable halves

54

wires

56

inner space

Claims (19)

1. Method for producing a cable harness, in particular a dimensionally stable cable harness, with a number of individual cables, individual cables (22) being placed into a cavity (8) of a foaming mould (2), which comprises an upper part (6) and a lower part (4), a negative pressure acting between the lower part (4) and the upper part (6) being generated, and the individual cables (22) being encapsulated by introducing a foamable material into the cavity (8).
2. Method according to Claim 1, in which the negative pressure is generated in the cavity (8).
3. Method according to Claim 1 or 2, in which the negative pressure is generated in a negative-pressure space (16) arranged next to the cavity (8).
4. Method according to Claim 3, in which negative-pressure channels (16) running laterally along the cavity are provided.
5. Method according to Claim 2 or 3, in which different negative pressures are set in the cavity (8) and in the negative-pressure space (16), and in which in particular a lower negative pressure is set in the cavity (8) than in the negative-pressure space (16).
6. Method according to one of Claims 3 to 5, in which different negative pressures are set in different subregions (27) of the negative-pressure space (16).
7. Method according to one of Claims 2 to 6, in which the negative pressure in the cavity (8) is monitored during the filling of the foaming mould (2).
8. Method according to one of the preceding claims, in which an opening (10, 24, 26) in the foaming mould (2) to the cavity (8) is automatically closed when a pressure value in the cavity (8) is exceeded.
9. Foaming mould (2) for producing a cable harness, in particular a dimensionally stable cable harness, with a lower part (4) and with an upper part (6), which in the joined-together state form a cavity (8) which can be filled with foamable material for placing in a number of individual cables (22) of the cable harness, means which generate a negative pressure between the upper part (6) and the lower part (4) being provided.
10. Foaming mould (2) according to Claim 9, in which a negative-pressure space (16) is provided next to the cavity (8), and the negative pressure can be generated in the cavity (8) and/or in the negative-pressure space (16).
11. Foaming mould (2) according to Claim 10, in which the negative-pressure space (16) is subdivided into a number of subspaces (27), in which different negative pressures can be generated.
12. Foaming mould (2) according to Claim 10 or 11, in which negative-pressure channels (16) run laterally along the cavity (8).
13. Foaming mould (2) according to Claim 12, in which a number of negative-pressure channels (16) arranged next to one another are provided.
14. Foaming mould (2) according to one of Claims 9 to 13, in which the upper part (6) and the lower part (4) engage in each other.
15. Foaming mould (2) according to one of Claims 9 to 14, in which a sealing element (20) is provided directly adjacent to the cavity (8), between the upper part (6) and the lower part (4).
16. Foaming mould (2) according to one of Claims 9 to 15, which has an opening (10, 24, 26) to the cavity (8), which is provided with a valve (31) which closes automatically when a pressure value in the cavity (8) is exceeded.
17. Foaming mould (2) according to Claim 16, in which the valve (31) has a sealing element (32) which is movable and can be pressed against a sealing seat (48) when the pressure value occurs.
18. Foaming mould (2) according to Claim 16, in which the valve (31) is a one-way valve and is formed in particular in the manner of a cut-open champagne cork, which has a hollow-cylindrical region (42) and an adjoining closure flap (44).
19. Foaming mould (2) according to one of Claims 9 to 18, in which an outlet seal (30), through which the individual cables (22) can be led out from the cavity (8), is provided, the outlet seal (30) being formed by a stable seal support (50) and a seal part (52) which is attached thereupon and can be shaped.

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