WO2004035339A1

WO2004035339A1 - Expanded strip as support strip for chassis seals

Info

Publication number: WO2004035339A1
Application number: PCT/DE2003/002505
Authority: WO
Inventors: Ralf Sehr
Original assignee: Saargummi Gmbh
Priority date: 2002-10-12
Filing date: 2003-07-25
Publication date: 2004-04-29
Also published as: DE10247678B4; DE10247678A1; EP1613496A1

Abstract

The invention relates to a metallic strip, which finds application as support for a seal within the chassis of automobiles and is produced by the slitting method. The aim of the invention is to develop a metallic support strip which gives the seal of rubber-like material sufficient rigidity for production and assembly with low weight, has good stress and strain properties, has sufficient mobility and gives the seal a high clamping power. Said aim is to be achieved with the lowest possible production costs. Said aim is achieved by means of a selection of the arrangement and form of the slits in a support strip, whereby short inner slits (2.3) are combined with long outer slits (3.2) and long inner slits (2.2) are combined with short outer slits (3.3) such that a slight overlapping (a') or (a') is achieved between the inner and the outer slits and, at least for the most part, a sufficiently large separation (b') between two tips of opposing outer slits and at least for the most part a sufficiently large separation (d') between inner slits and the edge of the support strip (5) are achieved.

Description

P 02/08

Alternating cut tape as carrier tape for body seals

The present invention relates to a metallic tape which is used as a carrier for a seal made of rubber-like materials in the body area of automobiles and which is produced by the roller cutting method. When installing the seals with a metallic carrier tape, they are placed on appropriately designed flanges in the body area, and here in particular on doors and on the trunk lid. The metallic carrier tape ensures a sufficient clamping force of the seal on the plug-on flange and thus for a secure and permanent fit of the seal, which could not be guaranteed solely through the rubber-like material.

A carrier tape is produced by punching out recesses (punching process) or roll cutting slots and then stretching (roll cutting process) from a metal tape as an intermediate product, bending it into a U-shaped cross section and then extrusion-coating it with a rubber-like, flexible sealing material.

The basic requirements for such a carrier tape can be seen in the following points when used as part of a seal in the body area: high tensile strength,

- good stretching and compression behavior,

- high mobility in all directions,

- high clamping force,

- light weight as well

- low manufacturing costs.

The requirement for the highest possible tensile strength is based on the fact that the carrier tape is subjected to tensile stress several times during the production process, for example when overmoulding with the rubber-like material under high pressure or when bending into the U-shaped state, and should not tear in the process. which would disrupt the manufacturing process in terms of performance. Good stretching and compression behavior is particularly required when assembling the finished seal on the automobile; If the seal can be stretched or compressed in particular without the formation of folds, the fitter can compensate for length inaccuracies that occurred during the production of the sealing tape; the requirement for the smallest possible tolerances in the manufacturing process can be reduced, which reduces the costs for the manufacturing process.

A seal should be able to be flexibly shaped in all directions, so that the fitter can follow the predetermined course of the plug-on flange on the automobile body, which is curved in some areas.

A high clamping force between the seal and the mounting flange of the body ensures that the seal sits securely and permanently on the mounting flanges of the body parts.

In order to save manufacturing costs and fuel when operating the automobile, the weight of the seal should be kept as low as possible. For this reason, aluminum is often used as the carrier material, but this has negative effects on the strength properties of the carrier tape, which is why the tape thickness must be increased compared to a steel carrier tape. In addition, the design of the carrier tape should enable the most cost-effective production possible.

DE 695 01 998 T2 and DE 36 28 448 C2 describe metallic strips which are produced by the roll cutting process. The recesses are cut using a tool in the form of a thin line. The slits obtain their characteristic, wedge-shaped design by subsequently stretching the strip. With the rotary cutting process, however, only symmetrical recesses can be created. The shape of the recesses is therefore quite inflexible and can only be adapted to a small extent to a desired strength behavior. In the case of tapes which are produced using the roll cutting process, a greater material thickness is required, also reinforced by the notch effect which occurs, in order to achieve the same strength properties as in the case of a tape which has been produced by the punching process.

FIG. 1 shows another example of a carrier tape 6 which was produced by the roll cutting method. Elongated inner slots 2 and outer slots 3 were cut into the metallic base body 1 and then by stretching the Metal band brought into their characteristic, wedge-shaped design. Both slot shapes are arranged mirror-symmetrically to the center line 4 of the carrier tape 6, the inner slots being halved by the center line. Furthermore, both the tips of the inner slots 2.1 and the tips of the outer slots 3.1 and the tips of two outer slots 3.1 are directed towards each other. The tips of the outer slots are directed towards the center line, the tips of the inner slots towards the edge 5 of the metal strip. The outer slots 3 open out in the edge of the metal strip 5. The respective length of the inner and the length of the outer slots is the same over the entire length of the carrier tape. The two slot shapes overlap in a portion of their length with a dimension a. The size of the overlap is decisive for the tensile strength, the mobility and the stretching and compression behavior of the carrier tape. A slight overlap results in a high tensile strength but also a low mobility and an unfavorable stretching and compression behavior of the carrier tape, which complicates the installation of the seal, especially when the plug-on flange of the body is curved. By a large overlap, as was chosen in Figj r 1 and also in DE 695 01 998 T2 and DE 36 28 448 C2, a high mobility but a low tensile strength of the carrier tape are achieved. This fact is reinforced by the choice of three further dimensions. A small distance b between two mutually directed tips of outer slots 3.1 and a small, perpendicularly directed distance c between an inner 2 and an outer slot 3 and a small distance d between the tip of an inner slot 2.1 and the edge of the metal strip 5 reduce the Tensile strength, but increase the flexibility and the stretching and compression behavior of the carrier tape.

If the carrier tape is subjected to tensile stress, after a limit value of the tensile strength has been exceeded, a crack will form between the points of two outer slots 3.1 facing each other or between the tip of an inner slot 2.1 and the edge 5. As the stress increases, the crack continues until, for example, it runs continuously between the two tips and the carrier tape breaks. Increased by the notch effect, the failure of such a carrier tape according to Figure 1 occurs at such low tensions that the carrier tape during the manufacturing process of the body seals when injecting the rubber-like material in the extruder, during the tensile movement of the sealing strip in the extrusion process or when bending the carrier tape into the U-shape is exposed. The tensile strength of a carrier tape can of course also be influenced by the choice of a suitable material and the tape thickness. In contrast, there is the demand of the automotive industry for the lowest possible weight, so that the thickness is chosen as small as possible and aluminum is used instead of steel, which in turn has a negative effect on the strength behavior of the carrier tape. Furthermore, the strength of the tape according to Figure 1 is adversely affected by the leverage between the inner and outer slots. The greater the overlap a between the outer and inner slots, the greater this is. The disadvantage of the low tensile strength of a carrier tape, which was produced according to the roll cutting process, is offset by the advantages of the roll cutting process that there is no loss of material when punching is not required; on the contrary, the stretching of the band even results in a length gain, which, however, in turn has a negative effect on its strength properties due to the resulting reduction in cross-section of the carrier band.

DE 101 01 778 C2 describes a carrier tape whose short and long wedge-shaped recesses (reference numerals 2 and 3) have been punched out of the metal tape. The punching process has the advantage over the rotary cutting process that one has greater freedom in the design of the punched geometry. Through a favorable choice of the pattern of the punched holes, optimal values for the tensile strength and the stretching and compression behavior of the carrier tape can be achieved. The disadvantage of the stamping process, however, is the high manufacturing costs. These result on the one hand from the material losses that result from the large-scale punching out and on the other hand from the low production speeds. The low production speed is based on the clocked movement that the punching process brings with it. A further disadvantage of the stamping process is the occurrence of the so-called "hungry horse effect". This is understood to mean the optical effect that large-area punched-out areas in the carrier tape are visible due to the rubber-like material of the seal. This effect is undesirable in particular in the case of seals of which Clamping area is in the field of vision of the vehicle occupants and cannot be covered by a panel.

Proceeding from this, the invention has for its object to develop a metallic carrier tape that the seal made of rubber-like material for manufacture and assembly gives sufficient tensile strength with low weight and at the same time has good stretching and compression behavior, has sufficient mobility to be able to follow the specified directional course of the body parts and gives the seal a clamping force that ensures a secure and permanent fit of the seal the slip-on flanges of the body parts. In order to be able to perform these tasks with the lowest possible manufacturing costs, the carrier tape should be manufactured using the roll cutting process.

The object is achieved by a choice of the arrangement and shape of slots in a carrier tape according to the characterizing part of claim 1. Here, short inner with long outer and long inner with short outer slots are combined such that a slight overlap between the inner and the outer slots and at least predominantly a sufficiently large distance between the two tips of opposing outer slots and at least predominantly a sufficiently large distance between the inner slots and the edge of the carrier tape is achieved. This arrangement thus increases the tensile strength of the carrier tape to a level that allows a safe manufacturing process of the seal. Furthermore, good stretching and compression behavior and sufficient mobility of the band is achieved by reducing the distance between the inner and outer slots compared to a band according to FIG. 1; the number of slots is thus increased over a defined length.

The slight overlap between the inner and outer slots and the at least predominantly greater distance between the two tips of opposing outer slots means that a crack between the opposing tips of two outer slots will only develop with a higher tensile load than with a belt according to Figure 1. Furthermore, the leverage between inner and outer slots is reduced as a result of the tensile stress. The interchangeable cut tape according to FIG. 2 thus has a higher tensile strength than the carrier tape according to FIG. 1. This effect is supported by the at least predominantly greater distance between the tip of an inner slot and the edge of the tape. The invention is illustrated in FIG. 2 using an exemplary embodiment and is described below with reference to FIG. 2.

Figure 2 shows a carrier tape 6 before the bending process in the U-shape. Inner 2 and outer slots 3 are made in the metallic base body 1. The slots are arranged mirror-symmetrically to the center line 4. In contrast to Figure 1, however, both slot forms are in the long 2.2, 3.2 and short 2.3, 3.3 version.

These are arranged in an advantageous embodiment according to FIG. 2 so that in the longitudinal direction of the carrier tape, at least one side is followed by two opposite short outer slots 3.3 on a long inner slot 2.2 and that at least one short inner slot 2.3 follows the two opposite short outer slots 3.3 , Furthermore, a short inner slot 2.3 is followed, at least on one side, by two opposite long outer slots 3.2. This arrangement leads to overlaps a 'between a short inner slit 2.3 and a long outer slit 3.2 or a "between a long inner slit 2.2 and a short outer slit 3.3, which are less than the overlap a in FIG. 1. Short inner slits 2.3 and short outer slots 3.3 do not overlap.

A further effect of this arrangement is that the distance b 'between two tips 3.3.1 of short outer slots lying opposite one another is greater than the distance b in FIG. 1.

Also in the case of such an interchangeable cut tape according to FIG. 2, the distance d 'between the tip of a short inner slot 2.3.1 and the edge of the tape 5 is shorter than the distance d in FIG. 1. These factors increase the tensile strength of the carrier tape, but reduce it Stretching and compression behavior and its mobility. In order to counteract this, the distance c 'between an inner and an outer slot was reduced in FIG. 2 compared to the distance c in FIG. 1 and the number of slots was thus increased over a defined length.

In an advantageous embodiment, a high degree of mobility and good stretching and compression behavior of the band with sufficient tensile strength for the manufacturing process is achieved in that, according to FIG. 2, on both sides in the longitudinal direction of the band a long inner slit 2.2 two short inner slits 2.3 follow that between two short inner slits 2.3 there are two opposing long outer slits 3.2 and that between a long inner slit 2.2 and a short inner slit 2.3 two opposite short outer slits 3.3 are arranged.

LIST OF REFERENCE NUMBERS

1 metallic base

2 inner slits

2.1 Tip of an inner slot

2.2 long inner slot

2.3 short inner slot

2.3.1 Tip of a short inner slot

3 outer slot

3.1 Tip of an outer slot

3.2 long outer slot

3.3 short outer slot

3.3.1 Tip of a short outer slot

4 Center line of the carrier tape

5 edge of the carrier tape

6 carrier tape

a Overlap between an inner and an outer slot a 'Overlap between a short inner and a long outer slot a "Overlap between a long inner and a short outer slot b Distance between the tips of two outer slots b' Distance between the tips of two short outer slots Slots c, c 'distance between an inner and an outer slot d distance between the tip of an inner slot and the edge of the carrier tape d' distance between the tip of a short inner slot and the edge of the carrier tape

Claims

claims

1. Carrier tape for body seals with in the base body (1) introduced elongated inner (2) and outer slots (3), both the tips of the inner slots (2.1) and the tips of the outer slots (3.1), as well as the tips of two outer slots (3.1) are directed towards each other, characterized in that both the inner slots (2) and the outer slots (3) are formed in a long form (2.2, 3.2) and a short form (2.3, 3.3).

2. carrier tape for body seals according to claim 1, characterized in

- That in the longitudinal direction of the carrier tape (6) on a long inner slot

(2.2) at least on one side two opposite short outer slots

(3.3) follow,

- that two opposite, short outer slots (3.3) are followed by at least one short inner slot (2.3),

- That on a short inner slot (2.3) at least on one side two opposite long outer slots (3.2) follow.

3. carrier tape for body seals according to claim 2, characterized in

- That in the longitudinal direction of the carrier tape (6) two short inner slots (2.3) follow on both sides of a long inner slot (2.2),

- that between two short inner slots (2.3) two opposing long outer slots (3.2) are arranged,

- That between a long inner slot (2.2) and a short inner slot (2.3) two opposite short outer slots (3.3) are arranged.