Front part or rear part of a vehicle with at least two wheelhouse elements and at least one cross-member connecting the wheelhouse elements, and method for production

Abstract

The invention relates to a front part or rear part of a vehicle with at least two wheelhouse elements (14, 16) and at least one cross-member (18, 20) connecting the wheelhouse elements, which form a main body (22) made of a lightweight metal material, wherein at least one reinforcement element (24), formed from an expanded metal (26) or a metal blank, is embedded by casting in at least one wheelhouse element (14, 16) and / or in the cross-member (18, 20). The invention also relates to a method for producing such a front part or rear part.

Description

[0001] Description

[0002] "Front end or rear end of a vehicle with at least two wheel house elements and at least one cross member connecting the wheel house elements and method for manufacturing"

[0003] The invention relates to a front end or rear end of a vehicle with at least two wheel house elements and at least one cross member connecting the wheel house elements, which cross member forms a base body. In particular, the invention relates to a front end or rear end of a motor vehicle with a vehicle weight of up to 2.8 tonnes, of a light commercial vehicle with a weight of more than 2.8 tonnes, in particular more than 3.5 tonnes, or of a heavy commercial vehicle with more than 7.5 tonnes. Reference is also made to vehicles with a correspondingly designed front end or rear end, in particular to motor vehicles and specifically to commercial vehicles with such a front end or rear end. Furthermore, the invention relates to a method for producing such a front end or rear end.

[0004] In the past, vehicle bodies and chassis structures were often manufactured from a large number of individual parts that were glued, welded, or bolted together. In recent times, there has been a trend towards simplifying manufacturing processes by producing larger body elements and structures as large castings. One challenge in this context is that the highly stressed force introduction points of such components must withstand the loads that occur not only during normal vehicle operation, but also in crash situations in order to avoid any disadvantages in terms of crash safety compared to conventionally manufactured bodies and structures. This aspect has so far been taken into account by using a suitable material in the respective component, e.g. high-strength steel.However, this approach is cost-intensive, especially when it comes to a large cast component that only partially needs to have high rigidity.

[0005] Alternatively, it is known to partially stiffen certain areas by providing a suitable geometry or material accumulation. However, this is sometimes difficult or even impossible from a casting perspective, and in the case of material accumulation, it is associated with additional weight and corresponding disadvantages in the vehicle's performance and fuel consumption.

[0006] It is also known from FR 2 558 084 A1 to provide a cast element with an insert to partially increase rigidity. However, FR 2 558 084 A1 makes no reference to large cast components or to a basic element of a front or rear end with a cross member as described above.

[0007] DE 10 2022 000 631 A1 discloses a cast component for a vehicle body structure, which comprises a separately manufactured metal insert that is connected to a die-cast part by die casting. The metal insert is partially encapsulated by the die-cast part. In a method described in this document for producing a composite component, the metal insert is to be austenitized before being inserted into the die-casting mold, and the metal insert heated by austenitization is to be placed in the die-casting mold to be fully formed by the inflowing die-casting melt in the die-casting mold and hardened by cooling in the die-casting mold. This document also makes no reference to large cast components or to a basic element of a front or rear end with a cross member as described above.

[0008] DE 10 2018 213 490 A1 discloses a component and a method for producing a component. The component is intended to comprise at least two components, wherein at least a first component is intended to be embedded, at least in part, in a second component, and wherein the first component has or forms a boundary layer up to which the second component infiltrates the first component, thereby forming a transition zone. The component is intended, in particular, to be a die-cast component made of aluminum into which a steel insert is cast. This document also makes no reference to large-scale cast components or to a basic element of a front or rear end with a cross member as described above.

[0009] The invention is based on the object of providing a front end or rear end of a vehicle according to the preamble of claim 1, as well as a method for producing such a front end or rear end, which can be manufactured as a large cast part and offer increased crash safety. This object is achieved according to the invention with the features of the independent claims. Further practical embodiments and advantages of the invention are described in conjunction with the dependent claims.

[0010] A front end or rear end of a vehicle according to the invention has a base body formed from at least two wheel house elements and at least one cross member connecting the wheel house elements. The base body is made of a lightweight metal material. Furthermore, at least one reinforcing element formed from expanded metal or a metal plate is embedded by casting in at least one wheel house element and / or in the cross member of the base body. A lightweight metal material within the meaning of the invention is understood to mean, in particular, aluminum or magnesium. Particularly suitable metal materials are those that have greater strength than the lightweight metal material.Preferably, at least one of the strengths - tensile strength, compressive strength, flexural strength, or torsional strength - of the reinforcing element is increased compared to the respective strength of the light metal material, preferably the tensile strength and / or the compressive strength, and independently of this, at least two or three of the stated strengths of the material of the reinforcing element are preferably increased compared to the light metal material. As will be explained below with the help of further technical details, such a base body can be manufactured as a large casting, whereby crash safety is increased by means of the casting-embedded reinforcing element. The weight is reduced compared to a base body made exclusively and in one piece from the light metal material because the material accumulations mentioned above can be dispensed with.

[0011] In a practical embodiment of a front end or rear end according to the invention, the at least one reinforcing element is made of a material which, when heated by contact with liquid light metal using a casting process to produce the base body and subsequently cooled, experiences a strength-enhancing effect. The casting process refers in particular to an aluminum casting process or a magnesium casting process. If the above technical condition is met, a material can be selected for the reinforcing element which, in its basic state, i.e., before being embedded in the base body, is relatively soft, thus ensuring good formability. This can be used, in particular, to bring the reinforcing element into a suitable, in particular bent, shape.The strength-enhancing effect then occurs with the casting-technical embedding and the associated heating and subsequent cooling, so that the reinforcing element only exhibits the desired, increased strength during or after the production of the base body. The aforementioned strength refers to the strength of the reinforcing element that exists after the base body with the embedded reinforcing element has been produced. In the last-mentioned case, this strength is also increased compared to the strength of the reinforcing element before embedding in the base body. The cooling of the base body refers in particular to cooling the base body after production by casting to the ambient temperature, in particular to a temperature between approximately 15 °C and 25 °C, for example 20 °C.

[0012] In a further practical embodiment of a front end or rear end according to the invention, the at least one reinforcement element is made of an air-hardening steel and / or a medium-manganese steel, with medium-manganese steel also being referred to as medium-manganese steel. This refers to steel with a manganese content of approximately 4% to 12%.

[0013] With regard to air-hardening steels, particular reference is made to the materials Salzgitter Flachstahl LH®900 and RobuSal®800. In connection with these materials, explicit reference is also made to the material compositions and parameters, which are available in particular at https: / / www.salzqitter-flachstahl.de / fileadmin / mediadb / szfg / informationsmaterial / produktinformationen / kaitgewalztes f einblech / deu / lh 900 szfq Werkstoff blatt 3 15 3.pdf and at https: / / www.salzqitter-flachstahl.de / fileadmin / mediadb / szfq / informationsmaterial / produktinformationen / warmqewalzte produkte / deu / robusal r 800.pdf.

[0014] In a further practical embodiment, it is advantageous if the reinforcing element is made of a material that experiences a strength-enhancing effect upon contact with liquid light metal at a temperature of approximately 600°C to 1,000°C and subsequent cooling. It is further advantageous if the strength-enhancing effect occurs within the temperature range between 600°C and 800°C, particularly between 700°C and 750°C. Such temperatures are experienced by liquefied light metal materials during the casting process, particularly aluminum processed using the aluminum casting process. Medium-manganese steels in combination with a base body made of an aluminum material are particularly suitable for this embodiment.If the at least one reinforcing element is an expanded metal formed by making cuts in a sheet metal and alternately bending and / or stretching the material strips resulting from the cuts in opposite directions—in particular upwards and downwards—the resulting base body has a very high rigidity for its weight, which is advantageous for crash requirements. The incorporation of a reinforcing element formed from expanded metal is therefore particularly preferred.

[0015] Alternatively or additionally, in a front end or rear end according to the invention, the at least one reinforcing element can also be a flat element extending over a large part of the width of the at least one cross member and / or an arcuate element extending at least over an arcuate partial section of a wheel house element.

[0016] If the reinforcement element extends over a large part of the width of the cross member, in particular over more than 60 percent, preferably more than 70 percent, more than 80 percent or more than 90 percent of the width between the inner sides of the wheel house elements, this results in a high transverse rigidity of the base body, by means of which the passenger cell in this area can be provided with increased rigidity, particularly in the event of a side impact. If the wheel house elements are provided with a corresponding reinforcement element, the transverse rigidity can be increased - in particular additionally - and the dimensional stability of the wheel house supports can also be increased, so that when forces act directly on a wheel house, the probability is increased that the shape of the wheel house will be maintained in such a way that there is no contact between the wheel house and a vehicle wheel, so that a vehicle remains drivable even after a collision.

[0017] Preferably, the at least one reinforcing element is fully embedded at least on one side, resulting in a large-area connection to the base body and making it unlikely that the reinforcing element will become loose or sheared off during a crash. Preferably, the at least one reinforcing element is fully embedded in the base body so that the reinforcing element is optimally protected from external influences and separation during a crash. In this respect, an approximately central arrangement within the base body with respect to the thickness of the base body is preferred. If an off-center arrangement of the reinforcing element is provided, it is possible to arrange the reinforcing element more towards the outside of the vehicle or more towards the inside of the vehicle.The arrangement more towards the inside of the vehicle has the advantage that the reinforcement element is optimally protected from external forces caused by intrusion forces from crash partners. The arrangement towards the outside of the vehicle has the advantage that intrusion forces initially impact the reinforcement element with greater strength, so that the forces are transferred from this harder element to the base body, which is essentially further inside the vehicle. If there is no risk of the reinforcement element becoming detached from the base body due to a sufficiently load-bearing connection and the geometric design of the reinforcement element (for example, essentially covering the entire surface of the base body on the outside), an arrangement of the reinforcement element on the outside of the vehicle on the base body is preferable from a crash perspective.

[0018] With regard to both lightweight construction aspects and a secure connection between the reinforcement element and the base body, it is preferred if, in a front end or rear end according to the invention, the reinforcement element has through-holes designed such that, after embedding by casting, they are completely filled with the light metal material. In this case, the reinforcement element has a reduced weight due to the through-holes. Furthermore, a very good and load-bearing connection is achieved between the reinforcement element and the base body, since the base body penetrates the connecting element in the area of ​​the through-holes, thus creating a large contact surface and good "interlocking" between the reinforcement element and the base body.

[0019] The invention also relates to a method for producing a front end or rear end as described above, according to which the reinforcing element is held by means of support structures made of the light metal material and then the base body made of light metal material is produced by at least partially encapsulating the reinforcing element, wherein the support structures are melted with a delay during the encapsulation process only when the reinforcing element is fixed in its relative position within the front end or rear end by the already hardened light metal. This can be achieved, for example, by providing the support structures on the underside while pouring occurs predominantly from the top side, in particular such that the casting mold is initially filled from the top side and only fills from the bottom side towards the end of the casting process.As soon as the casting mold is largely filled, the flow velocity decreases sharply, so that the flow around the support structures can be delayed if the casting mold and the pouring point(s) are selected in such a way that the area with the support structures is only reached by the liquid light metal towards the end of the filling of the casting mold.

[0020] In another embodiment of a method likewise according to the invention for producing a front end or rear end as described above, the reinforcing element is held by means of casting cores that are lost or demolded after the casting process. In the case of demolding, the casting process can be designed as desired to a large extent. If lost cores are used, similar boundary conditions must be observed as in the method described above, in which the support structures are melted. In this case, through openings remain in the area of ​​the lost cores after production, which allow visual contact with the reinforcing element. This can be advantageous if the material condition of the reinforcing element is to remain verifiable by visual inspection and / or material testing technology that requires direct access to the reinforcing element.

[0021] Further practical embodiments of the invention are described below in conjunction with the drawings. They show:

[0022] Fig. 1 shows a section of a vehicle with a rear section according to the invention, the embedded reinforcement element being shown in dashed lines,

[0023] Fig. 2 shows a section of a reinforcing element designed as expanded metal,

[0024] Fig. 3 shows a section of a reinforcement element designed as a perforated sheet and

[0025] Fig. 4 is a schematic representation of a casting mold with support structures for supporting a reinforcing element during the casting production of a front or rear vehicle according to the invention.

[0026] Figure 1 shows a section of a vehicle 10 with a rear end 12 and is formed from a first wheel house element 14 and a second wheel house element 16, each of which extends in an arc over a wheel house cutout on the outside of the vehicle 10. In the embodiment shown, the wheel house elements 14, 16 are connected to one another via a first cross member 18 and a second cross member 20 to form a base body 22. In the embodiment shown in Figure 1, a reinforcing element 24, shown in dashed lines, is embedded in the first cross member 18. This reinforcing element is located entirely within the first cross member 18 and is therefore shown in dashed lines.

[0027] The base body 22 is made of aluminum using an aluminum casting process. In the embodiment shown, the reinforcement element 24 is completely embedded in the first cross member 18 by casting. The reinforcement element 24 extends across the entire width between the wheel house elements 10, 16.

[0028] Figures 2 and 3 show two different embodiments of various reinforcing elements 24.

[0029] In the embodiment shown in Figure 2, the reinforcing element 24 is formed from an expanded metal 26. The expanded metal 26 is formed from a plurality of material strips 28, which are alternately separated from one another by bending and stretching the material strips 28 in different directions, here upwards and downwards. To produce the expanded metal 26, slits of approximately equal length are provided, forming the material strips 28. In the areas where no slit is provided between the material strips 28, so-called nodes 30 are provided.

[0030] Figure 3 shows a reinforcement element 24 in the form of a perforated plate 32. The perforated plate 32 has a plurality of through-openings 34, which are square in the embodiment shown. However, it is also possible to provide the through-opening 34 in other shapes, in particular circular, oval, rectangular, polygonal, or otherwise shaped.

[0031] Figure 4 shows a schematic representation of a casting mold 36 with support structures 38 for supporting a reinforcing element 24 during casting production. The casting mold 36 has a pouring section 40 arranged on the top. Liquid metal, in particular liquid aluminum, flows into the casting mold 36 via the pouring section 40 and flows around the reinforcing element 24.

[0032] The liquid metal only reaches the support structures 38 towards the end of the casting process, when the casting mold 36 is already largely filled with liquid metal. The support structures 38 can, in particular, be made of the metal casting material, so that the support structures 38 are melted by the identical liquid metal after the support structure 24 has already been held by solidified material on the top, sides, and partially on the bottom.

[0033] Alternatively, the support structures 38 can also be designed as lost cores or as demoldable cores that are removed after the casting process. In the latter case, through openings remain in the area of ​​the support structures 38 after demolding and removal of the cores, allowing direct visual contact and access to the support structure 24 even after the front or rear end of the vehicle has been manufactured.

[0034] The features of the invention disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. The invention may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

[0035] List of reference symbols

[0036] Vehicle Rear end First wheel house element Second wheel house element First cross member Second cross member

[0037] Base body reinforcement element expanded metal

[0038] Material strips nodes perforated sheet

[0039] Through opening casting mold

[0040] Support structure pouring section

Claims

Patent claims 1. Front end or rear end of a vehicle with at least two wheel house elements (14, 16) and at least one cross member (18, 20) connecting the wheel house elements (14, 16), which form a base body (22) made of a light metal material, characterized in that at least one reinforcing element (24) formed from an expanded metal (26) or a metal plate is embedded by casting in at least one wheel house element (14, 16) and / or in the cross member (18, 20).

2. Front end or rear end according to the preceding claim, characterized in that the at least one reinforcing element (24) is made of a material which, when heated by contact with liquid light metal using a casting process and subsequent cooling, experiences a strength-enhancing effect.

3. Front end or rear end according to one of the preceding claims, characterized in that the at least one reinforcing element (24) is made of an air-hardening steel and / or a medium-manganese steel.

4. Front end or rear end according to one of the preceding claims, characterized in that the reinforcing element (24) is made of a material which, upon contact with liquid light metal material at a temperature of approximately 600 °C to 1,000 °C and subsequent cooling, experiences a strength-enhancing effect.

5. Front end or rear end according to one of the preceding claims, characterized in that the at least one reinforcing element (24) is an expanded metal (26) which is formed by making cuts in a sheet metal and alternately bending and / or stretching the resulting material strips (28) in opposite directions.

6. Front end or rear end according to one of the preceding claims, characterized in that the at least one reinforcing element (24) is a flat element extending over a large part of the width of the at least one cross member (18, 20) and / or an arcuate element extending at least over an arcuate partial section of a wheel house element (14, 16).

7. Front end or rear end according to one of the preceding claims, characterized in that the at least one reinforcing element (24) is embedded over its entire surface at least on one side (preferably completely embedded so that it is arranged completely within the base body (22)).

8. Front end or rear end according to one of the preceding claims, characterized in that the reinforcing element (24) has through openings (34) which are designed such that they are completely filled with the light metal material after the casting embedding.

9. Method for producing a front end or rear end (12) according to one of claims 1 to 8, characterized in that the reinforcing element (24) is held by means of support structures (38) made of the light metal material and then the base body (22) is produced from light metal material by at least partially encapsulating the reinforcing element (24), wherein the support structures (38) are only melted with a delay during the encapsulation when the reinforcing element (24) is fixed in its relative position within the front end or rear end (12) by the already hardened light metal.

10. A method for producing a front end or rear end (12) according to one of claims 1 to 8, characterized in that the reinforcing element (24) is held by means of casting cores which are lost or demolded after the casting process.

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