LOAD INTRODUCTION DEVICE AND METHOD FOR ADHESIVE BONDING OF A LOAD INTRODUCTION DEVICE

Abstract

A load introduction device and a method for adhesive bonding of a load introduction device for fiber composite materials is disclosed. A sealant, particularly a first adhesive is used in the creation of a cavity and in the creation of a secured arrangement for the injection of adhesive into the cavity.

Claims

1. A method for connection of at least one fiber composite work piece, especially a longitudinal member of a vehicle, with a load introduction device, especially a metallic load introduction device, said method comprising: a. making available at least one fiber composite work piece and making available a load introduction device having at least one adhesive surface; b. positioning the load introduction device relative to the at least one fiber composite work piece so that at least one cavity is produced between the at least one fiber composite work piece and the least one adhesive surface of the load introduction device, and securing an arrangement of the fiber composite work piece and the load introduction device in such a way that the arrangement is suited to withstand a first pressure in the at least one cavity for at least a first time period or a first injection loading through injection of an adhesive into the at least one cavity, especially without permanent and/or temporary alteration of the arrangement; c. injection of the adhesive at least at a second pressure in at least one second time period into the at least one cavity, especially through a cutout or a plurality of cutouts in the load introduction device, especially boreholes in the load introduction device; i. until the adhesive reaches an expansion, especially a pre-planned expansion, which is defined over at least 10% of a contour of the adhesive expansion in the at least one cavity and/or the contour of the load introduction device by the contour of the load introduction device and/or by control cutouts arranged in the load introduction device, or which corresponds to the contour of the load introduction device and/or is parallel to the contour of the load introduction device, especially in view of a fiber composite material; or ii. until an amount of adhesive is injected which results in an expansion, especially an intended expansion, of the adhesive over at least 10% of the contour of the adhesive expansion in the at least one cavity and/or the contour of the load introduction device, by the contour of the load introduction device and/or by control cutouts arranged in the load introduction device, especially boreholes, or which corresponds to and/or is parallel to, the contour of the load introduction device; and/or iii. wherein the expansion of the adhesive between the fiber composite material and the load introduction device is not hindered and/or limited by the load introduction device, the fiber composite material, and/or other media and until the cavity is at least 50% filled with adhesive, wherein the at least one second pressure does not exceed the first pressure and the second time period does not exceed the first time period, or the loading via injection does not exceed the first injection loading, and the arrangement of the fiber composite work piece and the load introduction device is secured at least for the duration of injection by securing the load introduction device relative to the fiber composite work piece by external means, at least in relation to the forces which are exerted by the injection, the external means comprises one of at least one robot arm, at least one tensioning means, at least one holding clamp, at least one holding means, and at least one pressing means.

2. A method for connection of at least one fiber composite work piece, especially a longitudinal member of a vehicle with a load introduction device, especially a metallic load introduction device, said method comprising: a. providing at least one fiber composite work piece and providing a load introduction device having at least one adhesion surface; b. positioning the load introduction device relative to the at least one fiber composite work piece while using at least one sealant so that at least one cavity is produced with a cavity volume between the at least one fiber composite work piece and the at least one adhesion surface of the load introduction device, wherein the cavity has n areas on which the cavity volume is not limited by the at least one adhesion surface of the load introduction device and the at least one adhesive surface of the at least one fiber composite work piece, wherein n is equal to or greater than one and the length measured perpendicular to a shortest connecting line between the fiber composite work piece and the at least one adhesion surface of the load introduction device, which n areas amount altogether to at least 5 cm and so that the n areas are closed over at least 90% of an overall length of the n areas by at least one sealant, and wherein the at least one sealant is in contact with the at least one fiber composite work piece and/or the load introduction device, especially with the at least one adhesion surface of the load introduction device, and/or is configured as integral with the at least one fiber composite work piece and/or the load introduction device, and the arrangement of the fiber composite work piece and the load introduction device is secured so that the arrangement is suited to resist a first pressure in the cavity for at least a first time period and/or a first injection load resulting from the injection of adhesive into the cavity and without parting and especially without permanent alteration of the arrangement; c. injection of the adhesive with at least a second pressure in at least a second time period into the cavity until the cavity is at least 50% filled with the adhesive, wherein the at least one second pressure does not exceed the first pressure and the second time period does not exceed the first time period or the loading by injection does not exceed the first injection loading, and wherein the arrangement of the fiber composite work piece and the load introduction device is secured by exerting a force on the load introduction device and/or the fiber composite work piece that compresses the at least one sealant at least for the duration of the injection, and wherein the securing is effected by fixing, at least with respect to the forces that are exerted by the injection, the load introduction device relative to the fiber composite work piece by external means, and wherein the external means comprises one of at least one robot arm, at least one tensioning means, at least one holding clamp, at least one holding means, and at least one pressing means.

3. The method of claim 1, wherein the use of the at least one sealant occurs by insertion of the at least one sealant, and wherein the insertion of the at least one sealant is carried out by arrangement of at least one elongated elastic seal along an outer contour of the at least one adhesion surface of the load introduction device and/or along the outer contour of the load introduction device, especially by arrangement of the at least one elongated elastic seal and one at least has an elongated elastic seal that has, especially in its cross section, on at least one, especially on two or three sides a stabilizing and/or surrounding frame.

4. The method of one claim 3, wherein the at least one elongated elastic seal is admitted in a frame and/or is secured, and/or the at least one elongated elastic seal is configured to be inflatable and is inflated before the injection, and/or wherein the at least one elongated elastic seal and the adhesive are selected so that the adhesive does not bind with the at least one elongated elastic seal and/or whereby the frame and/or the at least one elongated elastic seal cause the securing and/or support the securing, and/or through the securing by means of the load introduction device are held and/or wherein the at least one elongated elastic seal and/or the frame serve as a spacer between the load introduction device and the fiber composite material and/or wherein at least one spacer is used to influence the spread of adhesive.

5. The method of claim 1, wherein at least one spacer is employed for positioning, and the at least one spacer is arranged between the at least one fiber composite work piece and the at least one load introduction device.

6. The method of claim 1, wherein a ventilation is made possible or is implemented during the injection, and the ventilation is made possible or implemented through one of at least one non-closed part of at least an area.

7. The method of claim 2, wherein after the injection, the n areas are completely closed.

8. The method of claim 1, wherein the injection occurs while a pressure of less than 20 bar prevails in the cavity volume that is not yet filled with adhesive, and/or a pressure of less than 500 mbar prevails before a start of the injection.

9. The method of claim 1, wherein air injected into the cavity and/or into a ventilation cavity connected in air-permeable fashion with the cavity of the load introduction device is compressed.

10. The method of claim 1, wherein at least three openings are provided in the cavity and the injection is carried out as a staggered injection so that when a flow front of the adhesive that is injected through a first opening reaches a second opening and/or reaches an area with an extension of up to 50 mm about a second of the openings, the injection through the second opening and/or a third opening is continued until the adhesive injected through the second opening reaches a third opening and/or the adhesive injected through the third opening reaches the second opening.

11. (canceled)

12. A load introduction device for introducing a load into at least one fiber composite work piece in an adhesively bonded state with the at least one fiber composite work piece, wherein the load introduction device has at least one adhesion surface for adhesive bonding with the at least one fiber composite work piece by means of adhesive, wherein the load introduction device has at least one device for injection of adhesive through the load introduction device and the at least one adhesion surface, and the geometry of the load introduction device is such that with arrangement of the at least one adhesion surface over a surface of the at least one fiber composite work piece at an interval between 1 and 15 mm and with injection of the adhesive through the at least one device for injection of adhesive, the adhesive is distributed between the load introduction device and the at least one fiber composite work piece so that a contour of the adhesive covers over at least 10%, especially at least 50%, of an extension of the contour of the load introduction device in viewing the surface of the at least one fiber composite work piece and/or runs parallel to the contour of the load introduction device without being limited in the adhesive's spreading between the load introduction device and the at least one fiber composite work piece by the load introduction device and/or other media, and/or the geometry of the load introduction device is so configured that the contour of the load introduction device or of at least one of the load introduction device's sides and/or adhesive surface segments, squared in relation to a surface of the load introduction device's sides and/or adhesive surface segments is greater than 18.

13. The load introduction device claim 12, wherein the load introduction device has at least one spacer and/or wherein the at least one adhesive surface has at least two adhesive surface segments which are arranged to lie opposite each other, and/or wherein the at least one adhesion surface has at least two adhesion surface segments between which at least one adhesive surface has or encloses at least one angle or edge.

14. The load introduction device of claim 12, wherein at least one adhesion surface is in connection with at least one adhesion surface segment and contains a ventilation cavity configured so that air is pushed from the at least one adhesion surface segment into the ventilation cavity and is compressed in the ventilation cavity starting from a pressure on the at least one adhesion surface that is over normal pressure or that is a maximum of 100 mbar over a pressure in the ventilation cavity up to a pressure of at least 5 bar.

15. A system comprising at least one fiber composite work piece and a load introduction device according to claim 12, for load introduction into the at least one fiber composite work piece, wherein the at least one fiber composite work piece and the load instruction device are connected via an adhesive bonding with an adhesive volume, wherein a surface of the adhesive volume is limited in part on a first part of the surface of the adhesive volume by the at least one fiber composite work piece and on a second part of the surface of the adhesive volume by the load introduction device, and on a third part the surface lies free, and wherein the third part amounts to at least 50%, especially at least 80%, of a difference value, especially in essence or totally equal to the difference value, wherein the difference value arises from the surface of the adhesive volume minus the first part of the surface of the adhesive volume and minus the second part of the surface of the adhesive volume and minus the surface of the adhesive volume that is together totally surrounded by the fiber composite material and the load introduction device.

16. Employment of at least one elongated elastic seal for an injection adhesive bonding of at least two parts by injection of a second adhesive at an injection pressure, wherein the at least two parts are at least one fiber composite work piece and at least one load introduction device; wherein the at least one elongated seal is arranged along an outer contour of at least one adhesive surface and/or along the outer contour of the at least one load introduction device, wherein the at least one elongated elastic seal is used so that the at least one elongated elastic seal comes to be or is in contact with both of the least two parts, and the at least two parts are secured before the second adhesive is injected into a cavity, and the cavity and/or the at least one elongated elastic seal resists the injection pressure, especially without alteration, and wherein a force compressing the at least one elongated seal is exerted at least for a duration of the injection, and/or the securing is exerted by securing of the at least one load introduction device relative to the at least one fiber composite work piece through external means at least in regard to the forces that are exerted due to the injection, and wherein the external means comprises one of a robot arm, at least one tensioning means, at least one holding clamp, at least one retaining means, and at least one compressing means and at least one load introduction device according to claim 12.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0080] Further advantageous embodiments are shown purely as examples without limitation using the following figures. Shown are:

[0081] FIG. 1: a cross section through an arrangement of a load introduction device and of a Fiber composite work piece

[0082] FIG. 2: a cross section through another arrangement of a load introduction device and a Fiber composite work piece

[0083] FIG. 3: A depiction of adhesive bonding without a sealant

[0084] FIG. 4: A depiction of various sealants

[0085] FIG. 5: A depiction of guidance of the adhesive through a spacer

[0086] FIG. 6: A depiction of a load introduction device with two sides, and

[0087] FIG. 7: A facing view of one of the sides of the load introduction device from FIG. 6.

DETAILED DESCRIPTION

[0088] FIG. 1 shows a load introduction device 1 and a fiber composite work piece made of fiber composite material 2 along with connection media 3, here designed as elastic, elongated round seals. Between the load introduction device, which has adhesive surfaces oriented downward, and the fiber composite work piece, a cavity 4 is formed. This is limited upwards by the load introduction device and downwards by the fiber composite work piece. The gap that is produced is closed outward by the seal 3. The load introduction device has injection and/or ventilation openings A, B, C to n. The curved brackets indicate that here more openings are placed but not shown, thus between opening C and n additional openings are found. Before an injection, especially first through opening A, from above pressure can be exerted on the load introduction device, so that the arrangement is secured. If the flow front of the adhesive that is injected through opening A, reaches opening B, injection through opening A is stopped and injection through opening B is continued until the adhesive reaches opening C. Then injection is carried out through opening C until the next opening is reached, and so on until the adhesive reaches opening n.

[0089] FIG. 2 shows a load introduction device 1 having three adhesion surface segments 9, which are arranged in a U-shaped cross section and a fiber composite work piece 2, which is at least partially surrounded on three sides by the load introduction device, along with a connection means 3, here designed as an elastic, elongated, round seal, and interrupted by a spacer 8 with a ventilation opening 10. Between load introduction device 1 and fiber composite work piece 2, a cavity 4 is formed. At the top this is limited by the load introduction device and by the fiber composite work piece. The resulting gap is closed toward the outside by seal 3. The height 11 of the cavity is larger on the upper adhesive surface segment than on the lateral adhesive surface segments 9. Load introduction device 1 has a beading 7 for adjusting the height 11 of the cavity. The height 11 of the cavity is also determined by seal 3 and spacer 8. The height of the cavity on upper adhesive surface segment 9 is adjusted by a spacer not shown in the depiction. For securing, the arrangement chosen here, due to its geometry, requires only a sufficient pressure from above on the load introduction device with a corresponding outer support under the fiber composite work piece. What is depicted is adhesive 5, which is injected in the direction of the adhesive expansion 6 through an injection opening 12 of load introduction device 1 into cavity 4. Beading 7 does not extend over the entire extent of load introduction device 1 parallel to the plane of the drawing, which makes it possible for adhesive to flow around the beading.

[0090] FIG. 3 shows, a composite work piece (2) with an omega-shaped cross section, at left in cross section and at right in a view of the side wall extending in the left depiction from above downwards. A load introduction device (1) is arranged with an interval on the fiber composite work piece (2). In the cavity situated between, adhesive (5) is injected through nine injection openings in the form of boreholes. Of the injection openings, four are on each side, of which one is shown in the right depiction and one in the surface that connects the two sides of the load introduction device.

[0091] The adhesive is injected on the sides with the two outer injection openings so that the adhesive can spread without hindrance in the cavity and its contour extends in wide segments parallel to the contour of the load introduction device. The adhesive was injected on the sides with the two center injection openings so that the adhesive at least could spread out unhindered in all directions in the cavity and extend forward tangentially at a location (above) to the contour of the load introduction device, coinciding with same at this point. Also downward the adhesive can spread unhindered, if necessary it is turned by 90, the spreading ends before the turning or it unites with the adhesive injected at the injection opening situated on the adjoining surface, so that a joint contour results, which, however, can spread unhindered.

[0092] FIG. 4 at left depicts as examples various designs of sealing elements, which especially are applied to enclose the contour of the adhesion surface and the load introduction device. In each case what is shown is a fiber composite work piece (below), a load introduction device (above), adhesive (between the fiber composite work piece and load introduction device) as well as a seal and part of a frame. In the uppermost depiction a sealing element, especially an elastic one, is seen, which extends between the fiber composite work piece and the load introduction device, and there can be secured by pressing the load introduction device in the direction of the fiber composite work piece. In the depiction below it a sealing element, especially an elastic one, is seen, compressed from without onto the load introduction device. In the depiction below that, a sealing element, especially an elastic one, is seen, that surrounds the load introduction device partially on the side facing away from the fiber composite work piece, and toward the left fully surrounds it, and thus it can secure the load introduction device in two spatial directions. By arranging such seals on four sides, the load introduction device can be secured in all the spatial directions, and also secured against the injection pressure so that under injection pressure it is secured in a position defined by the seal.

[0093] The lowest depiction shows a frame which partially surrounds the load introduction device on the side facing away from the fiber composite work piece, and completely surrounds it toward the left, and is secured on a seal, which limits the spreading of the adhesive. By arranging such seals on four sides, the load introduction device can be secured in all the spatial directions, and also secured against the injection pressure so that under injection pressure it is secured in a position defined by the seal.

[0094] At right in FIG. 4 is an example depiction of various embodiments of frames with inflatable sealing elements, each in an inflated state, which can especially be applied in surrounding fashion about the contour of the adhesion surface and the load introduction device. In each case is shown a fiber composite work piece (below), a load introduction device (above), adhesive (between the fiber composite work piece and load introduction device) as well as a frame with an inflated seal. The seal can extend only between the fiber composite work piece and load introduction device (second depiction from the bottom) or also next to the load introduction device (lowest depiction) or only next to the load introduction device and cavity (uppermost depiction), or also only adjoining the cavity (second depiction from the top and center depiction).

[0095] FIG. 5a depicts an embodiment of a spacer, which can also be used to affect or guide the spreading of the adhesive. As shown here as an example, such can consist of two elongated rods, here shown straight and parallel, and at least one connection element connecting therewith, here a ring, which lies on the rods and is connected with them. Advantageously the spacer is secured at least partially or fully in its position and/or orientation by placement in a recess in the load introduction element, especially an injection opening. For further or complete securing, it can also be arranged onto the load introduction device adjoining in more one direction.

[0096] FIG. 5b depicts the position between fiber composite work piece (below) and load introduction device (above) and of the ring in an injection opening. The arrow illustrates that adhesive is injected through the ring.

[0097] FIGS. 5c to 5e depict the unlimited spreading of adhesive (dashed lines) during the injection. First the spreading is hindered in two directions by the rods (FIG. 5c), then the adhesive flows around the obstacle that is formed by the spacer or its rods. Thereafter the adhesive can freely spread in all directions in the cavity (FIG. 5e). The contour is formed by the dashed lines and outlines of the rods. In FIG. 5c the contour is formed by the dashed lines (right and left) and the sections lying between of the inner sides of the rods. In FIG. 5d, the contour is formed by the dashed lines (right and left) and the inner sides of the rods. In FIG. 5e, the contour is formed by the dashed line and the contour of the rods surrounded by flow.

[0098] FIG. 6 shows a load introduction device for U-shaped enclosure of a fiber composite work piece as shown in FIG. 2. It has three flat adhesive surface segments. The end-placed or lateral sides of the load introduction device, of which one is shown in the vertical view of the adhesive surface segment in FIG. 7, has a ratio of contour squared and divided by the surface of M=57.9. If one considers the load introduction device shown in FIG. 6, one obtains M=76.5. When considering one side, as shown in FIG. 7, but without the lower (bending) edge, which is connected with the rest of the load introduction device, to be viewed as a contour, one obtains M=42.1. For this, the surrounding edge length has been summed with the edge length of the cutouts, the result was squared and divided by the surface of the side of the load introduction device as is perceived in FIG. 7. After arrangement on a fiber composite material, the load introduction device from FIG. 6 is adhesive bonded, especially one as shown in FIG. 2, by injection through the injection openings until the particular injected adhesive amounts form a contour that is identical with the rounded features of the load introduction device. The arrangement can be made by holding via a robot arm. Both sides of the load introduction device, of which one is shown in FIG. 7, then have four areas segregated from each other after the injections on one adhesive surface segment per side, on which they are adhesive bonded with adhesive. These areas are connected by the bars, which are included in the computation of the coefficient. In the configuration shown here the bars are also part of the adhesive surface segment, even when no adhesive bonding is done on them. However if one considers the coefficient of the adhesive per side, per side only the four circles that result through the four unimpeded injections would be allowed for, the contour of the four circles would be added, to square the result. This would then be divided by a number that results from addition of the surfaces of the four circles and squaring the result. If one considers this for the entire load introduction device, correspondingly eight circles would be involved.

LIST OF REFERENCE SYMBOLS

[0099] 1 Load introduction device
2 Fiber composite work piece made of fiber composite material
3 seal
4 cavity
5 adhesive
6 adhesive expansion
7 beading
8 spacer
9 adhesive surface segment
10 ventilation opening
11 height of cavity
12 injection opening