EP3911556A1

EP3911556A1 - Axle support for motor vehicles and production of said axle support

Info

Publication number: EP3911556A1
Application number: EP19701595.1A
Authority: EP
Inventors: Frank Gensty; Simone SPIELMANN; Herbert LETZGUS; Daniel EINSIEDLER
Original assignee: Albert Handtmann Metallgusswerk GmbH and Co KG
Current assignee: Albert Handtmann Metallgusswerk GmbH and Co KG
Priority date: 2019-01-18
Filing date: 2019-01-18
Publication date: 2021-11-24
Also published as: WO2020147963A1

Abstract

The present invention provides an axle support for at least one axle of a multi-track motor vehicle, comprising a main body having two mutually spaced, lateral longitudinal members and at least one cross-member connecting the longitudinal members, the main body being a die cast component cast as a single piece.

Description

l

Axle beams for motor vehicles and manufacture of the same

Field of the Invention

The present invention relates to an axle support, in particular a rear axle support, for motor vehicles and a method for producing such an axle support.

State of the art

Axle beams, which are also known under other names such as axle or subframes, integral frames, sub-beams or sub-frames, are provided as pre-assembled units or modules on vehicle bodies, for example on the body and / or on, after they have been provided with units or auxiliary units Side rails of a motor vehicle attached. The axle support is part of the axle module and can generally be described as an assembly support. The axle carrier is an essential part of the axle of a motor vehicle. The attachment to the vehicle body can be done indirectly via large rubber bearings and, in conjunction with the coupled wheel carrier, ensures greater driving stability and reduces the transmission of vibrations into the passenger compartment.

Axle beams are often characterized by a high level of integration of various functions: assembly and assembly carriers for the chassis linkage, engine mounting and fastening of the steering components for the front axle as well as the fastening of the axle drive on the rear axle. Defined crash properties, body stiffening and vibration behavior are also relevant. The axle carrier can also accommodate entire drive units and / or steering modules.

In order to ensure permanent use of the axle support with a low weight, it is usually made of a rigid and heavy-duty construction, such as an extruded aluminum profile, a steel or a fiber composite construction. The respective beams, i.e. longitudinal beams and cross beams, are usually provided with a large and solid cross section, which can withstand the high loads emanating from wheel-guiding handlebars in the long term.

In addition to the usual assemblies arranged on axle supports, such as stabilizers, handlebars and differentials, the increasing use of electric drive units in electrically driven and hybrid vehicles also places increased demands on the installation space of the axle supports.

Axle beams can be produced in a variety of manufacturing processes, for example as sheet metal welded together in several parts, as a deformed tube structure, as Pipe and sheet combination, as sheet / pipe with cast nodes as well as components formed by low pressure, mold or die casting. However, the known manufacturing processes are often complex and not very flexible.

For example, in a production from welded sheet metal, process risks can arise from the joining.

When casting molds, problems sometimes arise with the sand cores used. Due to technological restrictions, further stiffening inside a cross-section formed by permanent mold casting is not possible. The connection of die-cast components by means of die-casting welding can strongly depend on the casting quality, in particular on the presence of pores, and therefore often cannot be carried out with the desired rigidity.

It is therefore the object of the present invention to provide an inexpensive and flexible manufacturing method for axle supports which overcomes the disadvantages mentioned above. In particular, joining problems are to be avoided and at the same time a high level of functional integration of the axle supports is made possible. The axle beams produced are intended to meet the high requirements with regard to rigidity and resilience, in particular of multi-link axles with only transverse and diagonally arranged links. Furthermore, axle carriers with a compact design, which nevertheless meet the installation space requirements, in particular of electrically powered vehicles, are desirable. The axle supports are also intended to stabilize natural vibrations and, in particular, offer high stability against torsional vibrations. Finally, a flexible adaptation of the manufacturing processes and manufacturing tools to the production of small series is desirable.

Description of the invention

The above-mentioned objects are achieved by an axle support, in particular a rear axle support, for at least one axle of a multi-track motor vehicle, with a base body with two spaced-apart side longitudinal members and at least one cross member connecting the longitudinal members, the base body being a die-cast component that is cast in one piece. The side members can be connected by two or more cross members and / or an additional cross bridge as described below.

According to the invention, the base body of the axle beam, which comprises the two side longitudinal beams and the at least one cross beam, is cast in one piece using the die-casting method. This means that at least the two side longitudinal members and the at least one cross member of the base body are produced and connected to one another in a common die-casting step. In particular, the two side rails and the at least one cross member of the base body is not connected to one another in any other way, for example by gluing, welding, clinching, riveting and / or screwing. The connection between the two side members and the at least one cross member of the base body is rather cohesive and is created by the die casting itself. Furthermore, the connection of the two side longitudinal members and the at least one cross member of the base body is also not produced by casting or molding one or more of these carriers onto the other carriers.

The base body with the side longitudinal members and the at least one cross member is thus cast in a common die-casting mold by filling the liquid melt of the material used under high pressure. A permanent mold is generally used as the die casting mold. Both the hot chamber die casting process and the cold chamber die casting process can be used to manufacture the base body.

However, the manufacture of the base body as a one-piece die-cast component does not rule out the possibility of further components on the base body, for example receptacles or recesses for wishbones, trailing arms, struts, such as tension and push struts, stabilizers and fastenings and kinematic connection points of the axle beam on the body, Reinforcing ribs, receptacles for electric drive units, and the like, can be cast on or can be fastened in one of the other ways mentioned above. However, one or more of the said receptacles or recesses, fastenings and reinforcing ribs can preferably be formed together with the side members and the at least one cross member of the base body in the die casting step. For this purpose, an appropriately trained permanent shape can be used and / or corresponding tool inserts, i.e. Die casting tools are used in a basic form. It is understood that the cast die-cast component can be further processed mechanically, thermally or in some other way, for example in order to form one or more of the above-mentioned recesses or through openings. It is essential, however, that at least the base body with the two side members and the at least one cross member is a one-piece or one-piece die-cast component.

The longitudinal beams of the base body are, as is known per se, at least roughly designed as lateral beams along a longitudinal axis of the vehicle. The longitudinal beams spaced apart from one another perpendicular to the longitudinal axis of the vehicle are connected to one another by the at least one cross beam. The die-cast component thus forms a frame of the axle support, on which the usual units, stabilizers, links, struts and / or differentials can be arranged and attached. The die-cast component can have one or two or have more cross members, each of which connects the two longitudinal members to one another. In particular, the one-piece cast die-cast component can comprise two cross members which are spaced apart from one another in the longitudinal direction of the vehicle. The one-piece cast die-cast component can also have two or more cross members, which are arranged essentially one above the other. Relative location information such as the vehicle's longitudinal direction, longitudinal axis of the vehicle, arranged laterally, one above the other, above, below, right, left, front, rear and the like always refer to the usual installation of the axle carrier in the vehicle and the forward driving direction of the vehicle. For example, front components of the axle carrier are arranged in front of rear components of the axle carrier when viewed in the forward direction of travel of the vehicle. Otherwise, the terms used here and below, unless expressly defined otherwise, have the usual meanings in the field of vehicle construction.

The axle support can be designed as a rear axle support for at least one axle of a multi-lane motor vehicle. In particular, the at least one axle can be a multi-link rear axle. The axle carrier can be designed for one, two or more rear axles. Alternatively, the axle support can be designed as a front axle support for a steered front axle of a multi-track motor vehicle. In this case, the axle support can be designed such that it has components of a front axle support known per se, such as, for example, bearings for the pivot mounting of transverse and / or diagonal links, a mounting for a torque arm, a steering housing, for example for rack and pinion steering, and further conventional components, or wearing. The multi-lane motor vehicle can in particular be a two-lane motor vehicle. The motor vehicle can be a passenger car or a commercial vehicle.

According to a development, the base body can have a shell with a substantially U-shaped cross section, which is connected to at least one separately produced molded part by die casting. The shell can be positively connected to the molded part. In a special development, in particular when using materials for the molded part with a melting point similar to the material of the shell, a partially or completely integral connection can also be present. The shell, alone or in connection with the molded part, can have the essentially U-shaped cross section. The shell is cast integrally with the remaining parts of the base body, the at least one molded part being connected to the shell by the die casting itself, in particular in a form-fitting, material-fitting or partially form-fitting and partly material-fitting manner. According to this development, the base body comprises at least one partial area in which it is designed as an integrally, ie in one piece, cast shell with an essentially U-shaped cross section. In cross section the So peel a top surface next to the two free legs. As described in more detail below, the cover surface can encompass or be formed by the molded part.

The U-shaped cross-section gives the axle support a high degree of rigidity with a low use of materials. For example, at least partial areas of the two side longitudinal members and a transverse bridge can be designed as a shell with an essentially U-shaped cross section. Except for the above-mentioned receptacles or recesses as well as fastenings and kinematic connection points, the base body of the axle support can be designed in the form of the shell with an essentially U-shaped cross section. This results in a particularly compact design with excellent mechanical properties. However, the surface of the shell may deviate from a substantially smooth surface in some places or in sections as required. The shell can in particular be an upper shell, the top surface of which is arranged at the top. This facilitates installation in the motor vehicle.

According to a further development, the shell can be at least partially closed by at least one separately produced molded part. The molded part is designed and arranged in such a way that it at least partially closes the U-shaped cross section of the shell, the closed section of the shell nevertheless essentially having a hollow profile. In other words, the molded part closes the U-shaped cross section without completely filling the cavity. For example, the molded part can be arranged between or on the legs of the U-shaped cross section and extend at least along part of the shell. It goes without saying that two or more appropriately designed and arranged molded parts can also be provided in order to partially or completely close the cross section of the shell. For example, for each of the two side members and for each of the at least one cross member, a separate molding can be provided, which at least partially closes a U-shaped cross section of the respective member.

According to a development, at least one separately produced molded part can at least partially close a shell integrally cast with a U-shaped cross section. However, it is also conceivable that a part of the U-shaped cross section is formed by or comprises one or more further molded parts. However, both the other molded parts and the molded part closing the cross section are always connected to the base body and in particular the shell by die casting. In particular, the molded parts are not connected to the base body by other types of connection such as gluing, welding, clinching, riveting and / or screwing.

The at least one molded part is a separately manufactured component, and is therefore not only formed by the die casting step mentioned above. However, this does not preclude it the molded part is also a die-cast component that is produced in a separate die-casting process. Alternatively, the molded part can be a component that is produced in another casting process, for example in the mold casting process, by extrusion, rolling, or otherwise.

According to a development, the at least one molded part can be positively connected to the base body by die casting. According to a further development, the at least one molded part with the base body can be partially, i.e. in sections, cohesively or completely cohesively. The connection of the base body and the molded part can moreover be partially positive and partially material, for example in different connection areas. A cohesive connection here and below is a connection in which the connection partners are held together by atomic or molecular forces, for example by cohesion and / or adhesion. This connection is made by die-casting the body itself.

The at least one molded part can be connected to the shell by pouring or casting in during the die casting of the base body. When pouring, only a region of the molded part, for example an edge region, is enclosed by the cast material of the base body. When casting, the entire molded part is completely enclosed by the cast material of the base body. The formation of the connection of the at least one molded part to the shell during the die-casting of the base body is particularly long-lasting and has a high degree of rigidity. Despite the use of separate molded parts, the base body with at least partially closed U-profiles of the cast shell can thus be produced in one piece without separate joining steps.

In a special development, the cover surface of the shell can, as mentioned, have a separately produced molded part which is connected to the shell by pouring in or casting around during the die casting of the shell. Is the molded part poured into the shell, i.e. H. the legs of the U-shaped profile, connected, part of the top surface can thus be formed by the molded part itself. Is the molded part by casting around the shell, i.e. H. the legs of the U-shaped profile, however, the surface of the top surface, i. H. the surface of the cross member of the U-shaped profile, formed by the material of the legs. In this case, the top surface of the shell has, for example, a sandwich structure with the molded part in the middle.

In both cases, the mechanical properties of the shell and thus of the base body, such as rigidity and tensile strength, can be specifically influenced by a suitable selection of the material and the shape of the molded part. The molded parts connected to the base body have, for example, a stabilizing effect on the natural vibrations of the axle carrier and thus increase driving comfort. Furthermore, the molded parts closing the U-profiles move torsional vibrations of the axle beam to higher frequencies, which have a positive effect on driving comfort. For example, the U-profiles of the two longitudinal members can be closed at least partially by means of two molded parts, which results in an advantageous frequency shift of the torsional vibrations of the axle member. The molded parts can also be regarded as inlays or inserts, since, as described below, they are inserted into the die-casting mold for the base body at the beginning of the die-casting.

The at least one molded part can consist of a material whose melting temperature is higher than the melting temperature of the base body. In this way it is ensured that the molded part does not melt with the material of the base body during die casting, so that the shape and shape of the molded part specified in the separate manufacturing process remains unchanged during die casting of the base body. As a result, not only can the material properties of the at least one molded part be selected independently of the material properties of the base body, but a precise modification of the cast shape of the base body can be achieved by the molded parts. Depending on the use of the axle carrier, the desired mechanical properties such as rigidity, elasticity and vibration stability of the axle carrier can be advantageously influenced. The axle beams obtained can be flexibly adapted to the respective needs.

For example, the base body can be produced from a light metal, preferably from aluminum, or a light metal alloy, for example an aluminum, a zinc or a magnesium alloy. The light metal alloy can thus have in particular aluminum, zinc or magnesium as the base element. For example, an Al-Si secondary alloy such as AISil OMnMg can be used. The Al-Si secondary alloy can contain 3-12% by weight Si, 0.2-0.6% by weight Mg, 0.2-0.8% by weight Fe, less than 0.6% by weight. % Cu and less than 0.5 wt% Mn. Heat treatments are possible.

Alternatively, AISil OMnMg can be used with 9.5-1.5% by weight Si, 0.5-0.8% by weight Mn, 0.1-0.5% by weight Mg and approximately 0.15 % By weight of Fe can be used. Further components can be Cu with approx. 0.03% by weight, Zn with 0.07% by weight, Ti with 0.04 - 0.15% by weight, Sr with 0.01 - 0.025% by weight and P be about 0.001% by weight. The alloy can be heat treated according to T5 (without solution annealing), T6 or T7 (with solution annealing).

Alternatively, AISil OMnMg with 9.5-1.0% by weight Si, 0.5-0.8% by weight Mn, 0.2-0.5% by weight Mg and approx. 0.2 % By weight of Fe can be used. Further components can be Cu with approx. 0.03% by weight, Zn with 0.1% by weight, Ti with 0.15% by weight and Sr. Furthermore, the alloy can be heat treated with T5 or T6 (with solution annealing). According to Euronorm EN, EN AC 43500, EN AC 43500-T5 or EN AC 43500- T7 in particular can be used as light metal alloys for the base body.

The following variants are particularly conceivable as aluminum alloys:

• AISil OMnMg, standardized alloy according to DIN EN 1706 (EN AC-43500, EN AC- AISil OMnMg) o (heat treatment) conditions: F, O, T4, T5, T6, T7

• AIMg5Si2Mn, standardized alloy according to DIN EN 1706 (EN AC-51500, EN AC- AIMg5Si2Mn)

• Alloys from the group AISi9Mn, non-standard alloy without self-hardening (missing Mg), eg Castasil ^® -37 from Rheinfelden

Alloys of the group AISi7MnMg, non-standardized alloy e.g. according to VW TL 133

• Alloys from the group AIMg4Fe2, non-standardized alloy, eg Castaduct ^® -42 or Castaduct ^® -18 (with zinc) from Rheinfelden

The at least one molded part can be made of steel, iron, a steel alloy or an iron alloy. The alloy can thus have steel or iron as the base element. As mentioned, the material of the molded part can be chosen such that its melting point lies above the melting point of the material of the base body.

Alternatively, the at least one molded part can comprise or consist of a composite material. The composite material can in particular be a fiber or particle composite material. Combinations of several composite materials are also possible.

The use of composite materials for the molded parts allows a high degree of flexibility in determining the mechanical properties with a low weight, in particular for fiber-plastic composites.

The cavity between the molded part and the U-profile of the shell can be provided with a damping material after the die-casting step to dampen noise and vibrations, for example by foaming the cavity with aluminum or other materials.

The at least one molded part can in particular be designed as a sheet metal. In this case, the sheet can be flat or can be formed as a formed sheet, that is to say it can itself have a structure, for example an L shape or a T shape. Furthermore, the molded part itself can be partially, for example in sections and / or in cross section, or have a completely closed shape, for example a tubular shape with a round or angular, in particular rectangular, cross section. In general, the molded part can be flat or have a non-flat profile. Sheet metal with a thickness in the range of 0.5 to 3 mm, for example, can be used as molded parts.

According to a further development, the shell can extend over the region of the side longitudinal members and can be at least partially closed by the at least one molded part in the region of the side longitudinal members. In this way, torsional vibrations of the side members are damped and shifted in frequency.

According to a further development, the shell can have a multiplicity of rib, web, honeycomb and / or belt-like stiffeners, in particular reinforcing ribs on one side of the shell. In particular, the stiffeners can be located on an underside of an integrally cast upper shell of the base body. In areas which are closed by the at least one molded part, the stiffeners can be arranged within the cavity. The stiffeners can also be formed on a molded part during die casting without being directly connected to the remaining die cast parts of the shell. The reinforcements increase the rigidity of the base body without hindering the flexible use of the molded parts. The stiffeners can in particular be arranged obliquely to the course of the beams.

Furthermore, the base body can have a rear cross member, as seen in the direction of travel, reinforced with die-cast honeycomb. The rear cross member can in particular be designed as a rear vertical wall, the central region of which is formed with die-cast honeycombs. The die-cast honeycombs not only reduce the overall weight of the axle carrier, but also allow cables to be routed to the converted space of the axle carrier in a way that is optimized for installation space. Furthermore, the die-cast honeycomb stiffens the cross member with regard to strength in critical areas.

Additionally or alternatively, a lower, separately produced cross bridge can be provided, which is attached to the base body by gluing, welding, clinching, riveting and / or screwing. The lower cross bridge can in particular be arranged below a front cross member. The lower cross bridge can in particular be fastened to the base body without pretensioning. The lower cross bridge is therefore stiffening and can also be flexibly adapted to the respective requirements of the installation space. The lower cross bridge can also be made in one piece using die casting. In addition to any attachments or connection points for attaching the lower cross bridge to the base body, the lower cross bridge can have one or more receptacles for an electrical drive unit. As an alternative to manufacturing as one piece Die-cast component, the lower cross bridge can integrate other or further extruded profiles and / or cast parts that were produced by other casting processes.

According to a special development, the axle support can have a front cross member of the base body and a rear cross member of the base body reinforced with die-cast honeycomb, both of which are cast together with the side members in a common die-casting step. In addition, the axle beam can include the lower cross bridge described below below the front cross beam.

The described further developments of axle supports save joining costs due to the one-piece production in the die casting process and avoid process risks that can arise during joining. The die casting process is inexpensive and offers an extremely high level of functional integration. Variants can be created using tool inserts, i.e. Die casting tools. Possible problems when welding due to strong and / or difficult to control distortion are avoided. Furthermore, problems with the sand cores of a mold solution can be avoided with the die casting process used. Welding of die castings is generally avoided due to the one-piece design.

Any welded tabs, extensions or attachments can be attached to the integrally designed die-cast base body. The integrally designed main body of the axle beam is characterized by the integration of the load-bearing cross and longitudinal beams in a single die-casting mold.

The above-mentioned objects are also achieved by a method for producing an axle carrier, in particular according to one of the developments described above, with the following steps: inserting, inserting or inserting at least one molded part into a predetermined position of a die-casting mold for die-casting a base body of the axle carrier; and one-piece die casting of the base body in such a way that the at least one molded part is connected to the base body.

The same variations and developments that were described above in connection with the axle carriers according to the invention can also be applied to the method for producing an axle carrier.

For example, the die-casting mold can be designed such that the base body is formed with two spaced-apart, side longitudinal members and at least one cross member connecting the longitudinal members during die casting. Furthermore, the die casting mold can have space for inserting the at least one molded part at corresponding points. The at least one molded part is inserted or inserted into the open die, in particular the permanent die, before the die casting process begins. The die-casting mold is then closed and poured out with the material of the base body, for example the light metal alloys mentioned above, under high pressure. In die casting, the liquid melt can be pressed into the die under high pressure of approx. 10 to 200 megapascals and at a very high mold filling speed of up to 120 m / s (piston speed). As mentioned, a hot chamber die casting process or a cold chamber die casting process can be used to produce the base body. As described above, the at least one molded part can be designed with a higher melting temperature than the melting temperature of the base body and is produced in advance in one of the separate manufacturing processes described above. The melt can thus be filled in at a temperature which is below the melting temperature of the molded part. For example, the at least one molded part can be made of steel, iron, a steel alloy or an iron alloy. Alternatively, the at least one molded part can comprise a composite material, as described above, or be produced from such. As described above, the at least one molded part can be designed as a flat or formed sheet, in particular in tubular form.

Due to the higher melting temperature of the at least one molded part, it does not melt during the die-casting of the base body and essentially retains its original shape. The predetermined positions at which the at least one molded part is inserted into the die-casting mold can, as described above, be selected with regard to optimized rigidity, strength and stability against vibrations and in particular for the frequency shift of vibrations, in particular torsional vibrations and / or bending vibrations.

The at least one molded part is inserted into the die-casting mold in such a way that it is connected to the base body by the one-piece die-casting of the base body. This connection to the base body can, as described above, in particular in a form-fitting, material-fitting or partial, i.e. in sections, form-fitting and partially, i.e. in other sections, be cohesive.

Furthermore, as described in detail above, the base body can have a shell with an essentially U-shaped cross section, the at least one molded part being positioned in the die-casting mold in such a way that the at least one molded part is produced by the one-piece die-casting between the legs or on the legs of the U-shaped cross section is connected to the base body. After connection to the base body, the molded part can form a ceiling of the hollow profile closed thereby, arranged transversely between the free legs of the shell or on the free legs of the shell. Alternatively or in addition, a molded part can be connected to the legs of the shell be that it forms at least part of a top surface, ie the cross member, of the U-shaped cross section of the shell. The at least one molded part can be cast in or cast on by the one-piece pressure casting between or on the legs of the U-shaped cross section. When pouring, the cast material of the legs encloses an edge region of the molded part as described above. When casting on, a part of the legs, in particular their free end, is connected to the molded part, in particular in a cohesive manner. Alternatively, the material of the legs can be cast around the at least one molded part.

According to a special further development, the one-piece die-casting of the base body can additionally provide one or more receptacles and / or recesses for the control arm, in particular control arm or trailing arm, and / or stabilizers and / or struts and / or fastenings or kinematic connections of the axle support to a body of the Vehicle with be trained. In this way, the brackets mentioned can be connected to the base body without joining, which on the one hand increases the mechanical strength of the brackets and on the other hand simplifies the manufacturing process and is inexpensive. The consoles mentioned can be defined by releasably inserting corresponding die casting tools into a die casting basic mold.

According to a further development, receptacles for a separately produced cross bridge can be formed on one side of the base body by the one-piece die-casting of the base body, the manufacturing method of the axle beam further securing the separately produced cross bridge to the receptacles on the side of the base body by gluing, as described above , by welding, by clinching, by riveting and / or by screwing. As mentioned above, the side of the base body on which the separately produced cross bridge is attached can in particular be the underside of a base body formed with an upper shell. As described above, the cross bridge can be produced in a separate production step, in particular as a die-cast component with or without further extruded profiles and / or cast parts.

The manufacturing processes described allow the production of an axle beam with reduced joining costs. The integrally cast base body can be manufactured particularly cost-effectively in die casting and offers an extremely high level of functional integration. The possibility of flexibly inserting casting tools into a general die-casting mold, as well as the use of molded parts that are inserted, inserted or inserted into the die-casting mold at the beginning of the manufacturing process, allows the manufacturing process to be opened up simple and inexpensive way to adapt to a wide variety of vehicle types and requirements for the axle beams to be manufactured.

Further features and exemplary embodiments and advantages of the present invention are explained in more detail below with reference to the drawings. It is understood that the embodiments are not exhaustive of the scope of the present invention. It goes without saying that some or all of the features described below can also be combined with one another in other ways.

FIG. 1 shows a top view of an exemplary embodiment of a rear axle support according to the present invention.

FIG. 2 shows the underside view of the rear axle carrier belonging to FIG. 1 with a closed rear cross member.

Figure 3 shows a three-dimensional oblique view of the rear axle beam of Figure 1 with a honeycomb-reinforced rear cross member.

FIG. 4 shows an alternative further development of the rear axle support with an additional lower cross bridge.

FIG. 5 shows the underbody view of the rear axle support from FIG. 4.

FIG. 6 shows a three-dimensional detailed view of a lower cross bridge.

FIG. 7 shows a cross section along the line A-A in FIG. 5 with a molded or cast-in molded part according to various developments of the present invention.

FIG. 8 schematically shows a method for producing an axle carrier according to the present invention.

In the figures described below, the same reference symbols designate the same elements. For better clarity, the same elements are only described when they first appear. However, it goes without saying that the variants and embodiments of an element described with reference to one of the figures can also be applied to the corresponding elements in the other figures.

FIG. 1 shows a top view of an exemplary embodiment of a rear axle support according to the present invention. It goes without saying that the further development shown, in particular with regard to the shape of the axle support and the receptacles and cutouts provided, is only chosen to illustrate the present invention and is not to be understood in any way as limiting in this regard. The figure also shows an example of a rear axle support 100 in order to demonstrate the inventive concept of the one-piece cast base body. However, it is understood that the A person skilled in the art can also design and manufacture front axle supports according to the present invention by known modifications of the shape and arrangement of the base body.

The rear axle beam 100 shown in different views in FIGS. 1 and 2 comprises, in particular, the base body 1 10 cast in one piece as described in detail above. In the non-limiting further development shown here, this includes, in addition to the two side longitudinal beams 120a and 120b, two crossbeams 130a and 130b . FIGS. 1 to 5 also always indicate the direction of travel FR of the vehicle when driving forward, so that the cross member 130a represents a front cross bridge, while the cross member 130b represents a rear cross bridge.

Furthermore, FIG. 1 shows a top view of the top of the rear axle carrier 100. In this top view, a shell-shaped design of the entire front cross member 130a and large parts of the longitudinal members 120a and 120b can be seen. It goes without saying, however, that other areas of the base body 110 can also be of shell-shaped design, and that, conversely, partial areas of the supports of shell-shaped design in FIG. 1 can be of a different design, as long as the base body 110 has a cast shell at least in one area.

As an example, the rear axle support shown in FIG. 1 has receptacles 140a-d as kinematic connection points to the body of the vehicle. These receptacles are designed as hollow cylindrical through openings and are integrally connected to the base body 110. The through openings can be formed together with the base body by using appropriate die casting tools during die casting, or can be formed by mechanical processing of the base body after removal of the cast base body from the die casting mold.

Furthermore, the rear axle support shown has left and right receptacles 145a and 145b and, as can be seen from the underside view of FIG. 2, left and right receptacles 146a and 146b for further links and / or struts. In the further development shown, the receptacles for the further links and / or struts were formed integrally with the base body by die casting. Finally, the rear axle support has left and right receptacles 150a and 150b for various steering struts, for example spring links, which were also formed integrally with the base body by die casting. However, it goes without saying that the receptacles 145a, 145b, 146a and 146b and also the receptacles 150a and 150b can also be produced separately and then connected to the base body 110 by gluing, welding, die-casting welding, clinching, riveting and / or screwing . These receptacles can also be molded onto the base body after die casting. It is understood that the pictures shown are only are shown as examples and further and / or other receptacles or consoles can be provided.

In Figure 2, the rear axle beam 100 of Figure 1 is at an angle from below, i.e. shown in an underbody view. In addition to the elements in FIG. 1, the above-mentioned receptacles 146a and 146b for further handlebars and / or struts can be seen in FIG. Furthermore, it can be seen in the oblique view of FIG. 2 that the rear cross member 130b is formed with an essentially vertical, closed wall element 134. Only circular receptacles or bushings are provided here, on which, for example, an electric drive unit can be arranged. In the three-dimensional view of FIG. 3, in addition to the lower cross bridge 160, the design of the rear cross member 130b can be seen as a vertical wall. The rear cross member 130b is thus oriented substantially perpendicular to a running surface of the vehicle and has an expansion in this vertical direction that is adapted to the desired installation space.

An alternative development of the rear cross member 130b is shown in the three-dimensional oblique view of the rear axle member 200 in FIG. Here, the base body 210 of the rear axle beam 200 has a rear cross member 230b with a large number of die-cast honeycombs 235, which at the same time offer a high degree of rigidity of the rear cross member 230b while using little material. The die-cast honeycomb 235 can be formed together with the rest of the base body 210 in a common die-casting step, for example by using a suitable die-casting tool or sliders in a die-cast basic mold.

Returning to FIG. 2, it can be seen from the underbody view of the rear axle beam 100 that partial areas of the side longitudinal beams 120a and 120b and the entire front crossmember 130a were cast in the form of an upper shell with a substantially U-shaped cross section. As can be seen in FIG. 2, a multiplicity of reinforcing ribs 170 are provided on the underside of the upper shell. According to the invention, these reinforcing ribs are formed integrally with the base body by die casting. The reinforcing ribs 170 can, as shown in FIG. 2, be formed obliquely for the alignment of the longitudinal beams 120a and 120b in order to bring about a maximum increase in the rigidity. The U-shaped cross section of the parts of the base body 1 10 designed as a cast shell thus offers optimal mechanical properties, such as rigidity and stability against vibrations, with reduced use of material without joining steps. The parts of the base body 110 or 210 which are designed as a cast shell can in particular be designed as shown in FIG. FIG. 4 shows an alternative further development of the rear axle support with an additional lower cross bridge. As can be seen in the three-dimensional oblique view of FIG. 4, in this non-limiting further development of the rear axle support 300, a stiffening cross bridge 360 is provided, which is connected to the base body 310 of the rear axle support via screw connections 365a and 365b. The cross bridge 360 is produced as described above in a separate process, for example by producing a central part of the cross bridge in die casting and then connecting it to the screw connection elements 365a and 365b by joining. The separately produced cross bridge 360 is only attached to the base body 310 after the die casting has been completed.

As can be seen from the three-dimensional view of the rear axle beam 300 in FIG. 4, the stiffening cross bridge 360 is arranged below the front cross beam 130a of the rear axle beam 300. The transverse bridge 360 arranged in this way thus serves to absorb tensile and compressive stresses on the rear axle beam 300. The cross bridge 360 itself can, however, be fastened to the base body 310 without pretensioning.

FIG. 5 shows the underbody view of the rear axle beam 300 from FIG. 4. In addition to the elements already described in connection with FIG. 2, the additional transverse bridge 360 and its connection to the base body 310 via screw connections 365a and 365b can be seen in this view. FIG. 5 also shows a cross-sectional line A-A, along which the cross-sections of the right-hand side member 120b shown in FIG. 7 can be formed. It goes without saying that corresponding designs can also be provided for the left side member 120a and the front and / or rear cross member 130a or 230b.

FIG. 6 shows a separate three-dimensional view of the lower cross bridge 360. In this view, in addition to the central part 380, which is produced, for example, by die casting, the fastening elements 365a and 365b can be seen, with which the cross bridge 360 is screwed to the base body 310. In addition, the lower cross bridge 360 has two receptacles 375a and 375b for electric drive units with which the wheels of the rear axle can be driven electrically. It goes without saying that the illustrated development of the lower cross bridge is only exemplary and can be modified in accordance with the respective requirements. For example, other fastening elements, for example for gluing or welding, can be provided. Likewise, further and / or different brackets can be arranged on the lower cross bridge in order to implement the desired functions of the rear axle support. FIG. 7 shows a cross section of the U-shaped profile of the longitudinal beam 120b along the line AA in FIG. 5. Seven alternative connections of the molded part to the legs of the U-shaped cross section of the upper shell are shown in FIG. 7.

In the first partial figure a), the molded part 190a is arranged between the free legs 192a of the U-profile and completely encapsulated with the material of the base body. In this non-limiting development, the arrangement of the molded part 190a is selected such that the free legs 192a extend beyond the molded part 190a. The molded part 190a closes the cavity 195 as a cover layer. In the figure, some representative reinforcing ribs 170 are also shown in cross section, which are formed integrally with the shell-shaped profile during die casting. The molded part 190a can, however, also be arranged and cast in such a way that the free legs 192a of the U-profile are flush with the molded part.

In the second sub-figure b) of FIG. 7, an alternative development is shown, in which the molded part 190b is only cast in between or on the free legs 192b of the U-profile. This means that an edge region of the molded part 190b is surrounded by the material of the base body during die casting. Here too, the molded part 190b closes off a cavity 195 in the form of a cover layer.

According to the developments of sub-figures a) and b), the U-shaped cross section of the shell is cast integrally, while the molded part 190a or 190b is arranged between the free ends of the legs 192a or 192b and thereby closes the cavity 195 of the shell.

Alternatively, however, the molded part can also be arranged as part of the transverse element of the shell connecting the legs, and thus, as described above, form at least part of the top surface of the shell. Corresponding developments are shown in the sub-figures c) to f) of FIG. 7.

In sub-figure c), the molded part 190c is cast between the legs 192c of the U-shaped profile at a point opposite the free ends of these legs as part of the transverse element, i. H. in cross section completely surrounded by the material of the base body. In this way, the transverse element of the U-shaped shell has a sandwich structure with the molded part 190c in the middle. As is known, the reinforcing ribs 170 can be formed integrally with the shell-shaped profile during die casting.

In the partial figure d), the molded part 190d is only cast in between the legs 192d of the U-shaped profile at a point opposite the free ends of these legs, so that part of the transverse element is formed solely by the molded part 190d. Since the molded part 190d is already inserted in the die at the start of the die casting or is inserted, the reinforcing ribs 170 can be integrally formed with the shell-shaped profile during die casting. In the development of sub-figure d), some of the reinforcing ribs are molded onto a surface of the molded part 190d by die casting.

A modification of the further development of the partial figure c) is shown in the partial figure e). Here the actual surface of the top surface is formed by the material of the legs 192e, but part of the molded part 190e is exposed between the reinforcing ribs.

Part f) shows a modification of the development of part d), in which the reinforcing ribs 170 are integrally connected to the legs 192f, while the surface of the top surface is formed by the molded part 190f.

Finally, sub-figure g) shows a further modification of the further development of sub-figure c). Here, the molded part 190g has a tubular cross section. The top surface of the shell is formed by the material of the legs 192g. The tubular shaped part 190g has a cavity which can be foamed with aluminum or other materials.

It goes without saying that mixed forms and combinations of the developments in FIGS. 7a) -g) can also be used in the die-casting of the longitudinal and transverse beams of the axle beam.

Both the casting around the molded part 190a, 190c or 190g and the casting in of the molded parts 190b or 190d-f creates a positive or partially or completely material connection between the separately produced molded part and the base body 110. The molded part can be produced as described above in detail and indicated in FIG. 7 as sheet metal, for example made of steel or a steel alloy or one of the composite materials mentioned above. The molded part can be coated to produce an at least partially integral connection. The increased stiffness of the molded part can thus be used in a targeted manner in order to improve the mechanical properties of the U-profile of the base body. The arrangement and connection of the molded part with the U-profile can be selected such that natural vibrations of the rear axle support are damped and, in particular, torsional vibrations are frequency shifted as described above. It goes without saying that, depending on the position of the molded parts inserted into the die, oblique arrangements with respect to the cross section of the U-profile are also possible.

FIG. 8 schematically shows the steps of a method for producing one of the axle supports described above. In a separate manufacturing step 1, the at least one molded part is first manufactured. The molded part can be an extruded profile Rolling, by casting or otherwise manufactured. As described above, the molded part can be produced in particular from steel or iron or a steel or iron alloy. Alternatively, the molded part can be produced from a composite material, in particular a fiber composite material. For this purpose, fibers made of plastic, carbon or metal can be embedded in a matrix. Depending on the composite material, this can also be done by separate die casting.

If one is provided, the lower cross bridge is produced in a separate manufacturing step 2. As already mentioned, the lower cross bridge can be produced as a die-cast component with or without attached brackets and / or fastening elements. The known production methods for cross bridges, for example die casting, permanent mold casting, welding or the like, can be used for this purpose. The lower cross bridge 2 can also be manufactured at a later point in time.

In step 3, the die-casting mold for die-casting the base body is first opened. In step 4, the at least one molded part is inserted, inserted or inserted into the opened die-casting mold before the die-casting mold is then closed again in step 5. A pressure tool and / or spacer can be used to hold the at least one molded part in a desired position. In step 6, the melt of the material of the base body is filled into the closed die-casting mold under high pressure in order to produce the base body integrally by die-casting as described in detail above. Then the die-casting mold is opened in step 7 and the cast base body is removed. Optionally, a mechanical post-processing step 8 can follow, in which the integrally cast base body is further processed, for example for the production of kinematic connection points and for the attachment of receptacles and console-like elements. Preferably after this post-processing, the separately produced lower cross bridge is optionally attached to the base body in step 9.

The axle support thus formed at the same time has a high level of functional integration at generally low manufacturing costs. Due to the integral design of the base body, in particular joining problems can be avoided. Pouring or pouring the molded parts also allows the mechanical properties of the support, in particular its rigidity and stability against vibrations, to be influenced in a targeted manner. By using die casting tools, the shape and function of the axle carrier can also be flexibly adapted to the respective needs of the vehicle type.

Claims

Expectations

1 . Axle beam (100; 200; 300), in particular rear axle beam, for at least one axle of a multi-lane motor vehicle, comprising a base body (1 10; 210; 310) with two spaced-apart, side longitudinal beams (120a, 120b) and at least one cross beam connecting the longitudinal beams (130a, 130b; 230b), characterized in that the base body (1 10; 210; 310) is a one-piece die-cast component.

2. axle support according to claim 1, wherein the base body (1 10; 210; 310) has a shell with a substantially U-shaped cross section, which is connected to at least one separately produced molded part (190a-g) by die casting.

3. axle support according to claim 2, wherein the shell is at least partially closed by the molded part (190a, 190b).

4. axle support according to claim 2 or 3, wherein the at least one molded part (190a-g) is connected to the shell by pouring or casting around during the die-casting of the base body (1 10; 210; 310).

5. axle support according to claim 4, wherein the at least one molded part (190a-g) consists of a material whose melting temperature is higher than the melting temperature of the base body (1 10; 210; 310).

6. axle support according to one of claims 2 to 5, wherein the base body (1 10; 210; 310) made of a light metal, preferably of aluminum, or a light metal alloy, preferably an aluminum, zinc or magnesium alloy, and wherein at least one molded part (190a-g) is made in particular of iron or steel or a steel or iron alloy.

7. Axle carrier according to one of claims 2 to 5, wherein the at least one molded part (190a-g) comprises a composite material, in particular a fiber or particle composite material, or consists of such.

8. axle support according to one of claims 2 to 7, wherein the at least one molded part (190a-g) is designed as a flat or formed sheet or has a non-flat profile.

9. axle support according to one of claims 2 to 8, wherein the shell extends over the region of the side longitudinal members (120a, 120b) and is at least partially closed by the at least one molded part (190a, 190b) in the region of the side longitudinal members.

10. Axle carrier according to one of claims 2 to 9, wherein the shell has a plurality of reinforcing ribs (170) on one side of the shell.

1 1. Axle carrier according to one of the preceding claims, wherein the base body (210; 310) has a rear cross member (230b) reinforced with die-cast honeycomb (235) when viewed in the direction of travel.

12. A method for producing an axle carrier, in particular according to one of claims 1 to 1 1, with the following steps:

Inserting (4) at least one molded part (190a-g) into a predetermined position of a die-casting mold for die-casting a base body (110; 210; 310) of the axle support (100; 200; 300); and one-piece die casting (6) of the base body (1 10; 210; 310) in such a way that the at least one molded part (190a-g) is connected to the base body (1 10; 210; 310).

13. The method according to claim 12, wherein the base body (1 10; 210; 310) has a shell with a substantially U-shaped cross section, and wherein the at least one molded part (190a-g) is positioned in the die-casting mold such that the at least a molded part is connected to the base body (1 10; 210; 310) by the one-piece die casting between or on the legs (192a-g) of the U-shaped cross section.

14. The method according to claim 13, wherein the at least one molded part (190a-g) is cast or cast by the one-piece pressure casting between or on the legs (192a-f) of the U-shaped cross section.

15. The method according to any one of claims 12 to 14, wherein the at least one molded part (190a-g) is positively, materially or partially positively and partially integrally connected to the base body (1 10; 210; 310).

16. The method according to any one of claims 12 to 15, wherein by the one-piece die-casting of the base body (1 10; 210; 310) one or more receptacles and / or recesses (140a-d, 145a, 145b, 146a, 146b, 150a, 150b ) for handlebars and / or stabilizers and / or struts and / or attachments of the axle support (100; 200; 300) to a body of the vehicle.