Component for a motor vehicle
Disclosed is a component (1), particularly a crossbeam that is to be disposed between the A-shaped columns of a motor vehicle. Said component (1) comprises an essentially tubular or other elongate metallic basic member (1) to which a plastic (7) channel (2), especially a ventilation channel, is connected at least in part within the profile of said basic member (1), and a joining part (4) that is mechanically connected to the basic member (1) or a part rigidly connected thereto and is used for fixing another component. Said joining part (4) forms a material bond with the basic member (1) or a part rigidly connected thereto at a joining point (5), thus creating an intermediate area (12) so as to reduce heat transfer between the joining part (4) and the plastic (7) of the channel (2) and/or drain away a gas produced during the joining process.
The invention relates to a component, in particular a crossmember, for arranging between the A-pillars of a motor vehicle, with a basic body made from metal which is of essentially tubular design or is designed in the form of an elongated shell, i.e. an open profile, and with a duct, in particular ventilation duct, of plastic which is at least partially surrounded by the profile of the basic body and is connected mechanically thereto. A component of this type is known from DE 100 64 522 A1, for example.
In a motor vehicle, a saving on weight and/or construction space is possible by a crossmember connecting the A-pillars being used at the same time for guiding air. By lining the crossmember with plastic, both the stability of the crossmember can be increased and the probability of condensation from moisture contained in the air-conditioned air to be supplied to the vehicle interior can be reduced. Connecting points for further components, for example steering column or airbag, are typically arranged on the crossmember. Connecting points of this type are generally realized by joining parts welded to the crossmember. However, because of the thin-walled design of the crossmember that has only been made possible by the stabilizing plastic lining, the production of welding connections on the crossmember is problematic. The application of heat to the outer side of the crossmember very rapidly brings about an increase in temperature on its inner side, which can damage the plastic forming a ventilation duct. Furthermore, it is also possible for gas to be produced by the heated plastic or by evaporation of surface coatings, for example zinc layers. This gas may penetrate the molten metal of the weld seam and form pores or blow the liquid welding material out of the weld seam.
The invention is based on the object of indicating a component, in particular a crossmember of a motor vehicle, which comprises an elongated basic body made from metal and a duct, in particular ventilation duct, of plastic connected mechanically thereto, and is distinguished by particularly economical production and further processing possibilities.
This object is achieved according to the invention by a component with the features of claim 1. In this case, a duct formed at least primarily from plastic is connected mechanically to a metallic basic body essentially having the form of a tube or an open profile, in particular crossmember between the A-pillars of a motor vehicle. The basic body or a part connected rigidly thereto has at least one joining point for connection with a cohesive material joint to a joining part provided for the fastening of a further component. At least in the region of the joining point, the basic body, the part connected rigidly thereto and/or the duct has a form making it possible for an intermediate region to be provided between the joining point and the plastic forming a wall of the duct. The intermediate region reduces the heat transfer between the joining point and the plastic of the duct. The duct wall, which is at least predominantly formed from plastic, is therefore not disadvantageously affected by the application of heat at the joining point. In addition, if corresponding temperatures of the plastic are reached, the intermediate region preferably acts as a degassing opening or degassing gap and therefore permits the removal of gas formed from the plastic of the duct or from material evaporating from surface layers during the joining, in particular welding.
In a particularly economical manner, the duct is preferably connected to the profile of the basic body by means of the injection molding method in a force-transmitting manner. In this case, the plastic of the duct penetrates openings in the basic body during the injection molding method, so that the hybrid component produced in this manner has connecting elements, which are formed by the plastic in the manner of rivet connections. Additional connecting elements between the basic body, in particular crossmember, and the duct, in particular ventilation duct, are not required in this production method. The component is preferably designed geometrically in such a manner that, in order to produce the duct in the injection molding method, just a simply constructed injection mold, ideally in the form of what is referred to as an open-closed mold without or with a small number of additional slides, is required. Alternatively, however, the duct may also be premanufactured and connected mechanically to the component by adhesive connections, clip connections, collar-type joining and/or in another manner.
Irrespective of the production method, in particular IMA method (In-Mold Assembly) or PMA method (Post-Mold Assembly), the duct is already arranged in or on the component before the joining part, which serves, for example, for the fastening of an airbag or for the mounting of the steering column, is connected thereto with a cohesive material joint. By not connecting the joining part to the basic body until after the duct is introduced into the basic body or the duct is connected to the basic body, tolerance problems which are to be anticipated in other situations are avoided. Furthermore, this makes it possible in particular to produce economical manufacturing by injection molding with production at the same time of a strength-transmitting connection to the basic body without using complicated slides or sealing devices at the joining points.
According to a preferred refinement, the joining point is situated directly on the basic body. In this connection, if it is possible when the strength requirements are taken into consideration, the insertion of reinforcing additional parts, such as plates, into the profile of the basic body in the region of the joining point is omitted. In the region provided for the fastening of the joining part with a cohesive material joint, the basic body preferably has an embossed structure, in particular a knob or rib structure, which ensures that the joining point is spaced apart from the plastic of the duct. It is therefore possible solely by the form of the basic body to produce a spacing between the joining part and parts of the component which are formed from plastic, said spacing reducing the heat transfer between the joining point and the plastic. The embossed structure is preferably designed in such a manner that the wall of the duct, which is otherwise formed from plastic, is formed in the intermediate region adjoining the joining point exclusively from the material of the basic body. This can be realized in terms of manufacturing in a simple manner by the knobs, ribs or other embossed structures of the basic body being impressed from the outer side thereof to such a depth that the plastic applied to the inner side of the profile of the basic body to produce the duct only forms a wall of the duct in surface regions of the basic body outside the knobs, ribs or similar depressions—as viewed from the outer side of the profile. By contrast, in the region of the depressions mentioned, the wall of the duct is formed by the material of the basic body. An overall smooth, inner surface of the duct can be produced by the sum of the embossed depth of the embossed structure of the basic body and of the wall thickness of the basic body corresponding at least approximately to the wall thickness of the duct in the region outside the depressions. Overall, the inner surface of the duct, including the depressions which do not have any plastic, is formed for the most part from plastic, so that the condensation problems typically arising in the case of ducts made from metal are avoided. Furthermore, the embossed structure of the basic body at the same time increases the mechanical stability of the component in a particularly advantageous manner.
Despite the good heat conduction of the metallic basic body, regions of the duct wall that are lined with plastic or are formed entirely from plastic are spaced apart sufficiently far from the joining point in order to permit welding at this point. The at least limited thermal decoupling of the joining point from the duct makes it possible for the joining point to be configured with large dimensions with a correspondingly extensive introduction of force from the joining part into the basic body. This is all the more advantageous the thinner-walled the design of the basic body is. The component is therefore of particularly weight-saving design with a great degree of design freedom with regard to the arrangement and form of the joining parts. A particularly uniform, extensive introduction of force is preferably provided by the fact that the joining part is connected to the basic body with a cohesive material joint, in particular is welded, not only at individual points or lines, in particular outer contours, but also has joining points which extend over relatively large areas, for example in the form of weld seams in the manner of a honeycomb pattern or cross-hatching.
In the region adjacent to the joining point, the basic body preferably has one or more apertures, preferably holes or punched portions, as degassing openings, which form the intermediate region or part of the intermediate region. Degassing openings of this type, for example produced by a laser beam before the welding on of the joining part, are preferably combined with embossed portions of the basic body and/or of the joining part fastened thereon, which form ducts or other cavities through which gases arising during the joining method can escape. In addition, the joining part preferably also has openings and/or contours interacting with the degassing openings of the basic body.
According to a preferred development, the joining point is formed on at least one bent-outward part of the basic body, which bent-outward part is spaced apart at this point from the duct, in particular ventilation duct, and is bent outward, i.e. points away from the duct. Both a particularly large spacing of the joining point from the plastic of the duct and a particularly extensive connection of the basic body to the joining part can therefore be produced. A particularly economical production of the component is also made possible in this refinement by the fact that the joining point is arranged directly on the basic body, without further auxiliary elements.
In a departure from the previously described, single-part design of the basic body with the joining point arranged on the surface of the duct and/or on the bent-outward part, a separate part, in particular an “insert part”, can also be connected, for example welded, to the basic body, which part has the joining point for the connection with a cohesive material joint to a further component. In this case, the insert part preferably has a subregion arranged within the profile of the basic body, i.e. on that side of the basic body which faces the duct, and a subregion protruding out of the duct. The inner subregion is preferably injected into the duct at the same time as the duct is produced in the injection molding method, with, in comparison to an injection mold which is provided for producing a component without additional insert parts or adaptors, the injection mold not being of more complicated design or only being of insignificantly more complicated design, in particular not having an additional slide. In a particularly advantageous manner, an additional reinforcing of the component is provided by the insert part. The wall thickness of the insert part is preferably dimensioned in such a manner that the wall of the duct is free from plastic in regions in which the insert part bears against the basic body, with an overall at least approximately smooth surface being formed. The insert part therefore forms at least part of the intermediate region between the joining point, in particular welding root, and the plastic wall of the duct. In this case, the joining point is situated on that part of the insert part which is arranged outside the basic body and/or within a surface region of the basic body on which the inner subregion of the insert part rests. In particular in the design with separate insert parts, the component has the advantage that the manufacturing of various variants is possible without or only with slight modification of the basic body serving as the base part.
According to all of the above-explained designs of the component, the intermediate region is primarily produced by the design of a part manufactured from metal in order to protect the plastic of the duct. In a departure from this, or in a combination with these refinements, according to further refinements the at least one intermediate region, which preferably forms both an insulation space and a degassing gap, is produced by the surface structure of the plastic of the duct. This is advantageous in particular in cases in which a premanufactured ventilation duct is connected to the basic body by adhesive bonding and/or mechanical connecting devices. Intermediate regions are formed, for example, by ribs or other elevations of the duct, which is entirely manufactured from plastic, that bear against a essentially smooth inner surface of the basic body.
Irrespective of the geometrical design of the basic body and of the duct, the joining part is preferably connected to the basic body by means of a low-heat joining process, for example laser welding or electron beam welding. In this manner, even in the case of a thin-walled basic body, at most a small distortion occurs because of the joining.
The advantage of the invention resides in particular in the fact that, in spite of a thin-walled design of the basic body, an economical, reliable, mechanically highly loadable connection of the crossmember to joining parts to be fastened at the joining points is made possible by the strength-transmitting connection of a metallic basic body of a crossmember of a motor vehicle to a ventilation duct having a wall at least predominantly of plastic, and the formation of intermediate regions, which serve to reduce the heat transfer, between joining points arranged directly on the basic body and the plastic of the ventilation duct which is introduced into the basic body in the injection molding method.
A number of exemplary embodiments of the invention are explained in more detail below with reference to a drawing, in which:
FIGS. 4 to 7 show further exemplary embodiments of components in each case in a view analogous to
Parts which correspond to one another or act in an identical manner are provided with the same designations in all of the figures.
The arrangement according to
While the outer side 9 of the ventilation duct 2 is formed exclusively from the material of the basic body 1 in its top region in the illustration, i.e. above two webs 10 which adjoin the circular ventilation duct 2 in the radial direction as parts of the basic body 1, the inner side 11 has regions made from metal, namely the knobs 8, and otherwise a surface made from plastic 7. The wall thickness of the ventilation duct 2, which wall thickness is approximately constant over the entire circumference, is denoted by d, the wall thickness of the basic body 1 by a, and the embossed depth of the embossed structure 6 by p. As is apparent in particular from the view of the detail according to
FIGS. 4 to 7 each show, in a specific refinement of the basic example according to
The exemplary embodiments according to
In the exemplary embodiment according to
In a departure from the exemplary embodiments according to
The exemplary embodiments according to
The first joining point 5 is situated directly on the outer side of the basic body 1, on the left in
- 1 Basic body, crossmember
- 2 Ventilation duct
- 3 Component
- 4 Joining part
- 5 Joining point, weld seam
- 6 Embossed structure
- 7 Plastic
- 8 Knob
- 9 Outer side
- 10 Web
- 11 Inner side
- 12 Intermediate region
- 13 Hole
- 14 Bent-outward part
- 15 Limb
- 16 Eyelet
- 17 Aperture
- 18 Rib
- 19 Side wall
- 20 Base surface
- 21 Supporting limb
- 22 Fastening limb
- 23 Hole
- 24 Hole
- 25 Embossed structure
- 26 Opening
- 27 Fastening arm
- 28 Notch
- 29 Ribbed structure
- 30 Insert part
- 31 Inner section
- 32 Retaining arm
- a Wall thickness of the basic body
- b Wall thickness of the duct
- c Embossed depth
Claims
1. A component, in particular crossmember, for arranging between A-pillars of a motor vehicle, with a metallic basic body which has essentially a tubular form or another elongated form and to which a duct, in particular ventilation duct, of plastic is connected at least partially within the profile of the basic body, and with a joining part which is connected mechanically to the basic body or to a part connected rigidly thereto and is used for fastening a further component, characterized in that the joining part is connected at a joining point with a cohesive material joint to the basic body or to a part connected rigidly thereto with an intermediate region being formed in order to reduce the heat transfer between the joining part and the plastic of the duct and/or to conduct away a gas produced during the joining.
2. The component as claimed in claim 1, wherein the duct is connected to the basic body by means of plastic injection molding in a strength-transmitting manner.
3. The component as claimed in claim 1, wherein the joining point is arranged directly on the basic body.
4. The component as claimed in claim 3, wherein in the region provided for the fastening of the joining part, the basic body has an embossed structure which is designed in such a manner that the wall of the duct, which is otherwise formed from plastic, is formed in the intermediate region adjoining the joining point from the material of the basic body.
5. The component as claimed in claim 4, wherein the sum of the embossed depth (p) of the embossed structure and of the wall thickness (a) of the basic body corresponds at least approximately to the wall thickness (d) of the duct.
6. The component as claimed in claim 3, wherein the joining point is formed on a bent-outward part of the basic body, which bent-outward part points away from the duct.
7. The component as claimed in claim 1 wherein the joining point is arranged on an inset part connected rigidly to the basic body.
8. The component as claimed in claim 1, wherein on its outer side facing the basic body the duct has a surface structure forming the intermediate region.
9. The component as claimed in claim 1, wherein the jointing part is connected to the basic body at the joining point by means of a low-heat joining method.
Type: Application
Filed: Oct 15, 2004
Publication Date: Mar 15, 2007
Applicant: BEHR GmbH & CO. KG (Stuttgart)
Inventors: Thomas Feith (Korntal-Muchingen), Jochen Schmitz (Leonberg), Volker Unholz (Stuttgart), Walter Wolf (Oppenweiler-Zell)
Application Number: 10/575,910
International Classification: E21B 33/12 (20060101);