DE102016201815A1 - Subframe for a motor vehicle - Google Patents

Abstract

The invention relates to a subframe (1) for a motor vehicle which has at least two longitudinal members (4, 5) extending substantially in the direction of travel and at least two transverse members (2, 3) extending substantially transversely to the direction of travel. In addition, the subframe (1) comprises at least one cast node (6, 7) which connects a side member (4, 5) and a cross member (2, 3), wherein the cast node (6, 7) has a side member attachment point (22). and / or a cross-member attachment point (21). This subframe (1) makes it possible to minimize production costs and to save weight and costs. In addition, the subframe (1) offers the possibility to safely connect components made of different materials.

Description

The invention relates to a subframe for a motor vehicle.

Various types of subframe, also called subframe, are known from the prior art. Conventionally, these are composed, for example, of longitudinal and transverse beams, which consist of steel materials, assembled and joined. From the DE 10 2011 012 118 A1 an auxiliary frame is known in which the longitudinal members of an aluminum material and the cross member made of a steel material. The longitudinal members and the cross members are interconnected by means of cast nodes.

Based on this, the present invention seeks to further improve an auxiliary frame of the type mentioned in terms of the required manufacturing effort and to reduce the weight of the subframe.

This object is achieved by the subframe according to claim 1. The subframe according to the invention comprises at least two longitudinal members extending substantially in the direction of travel, at least two cross members extending substantially transversely to the direction of travel and at least one cast node connecting a side member and a cross member, wherein the cast node comprises a side member attachment point and / or a cross member Having binding site. Such a subframe has the advantage that components made of various materials (for example aluminum, steel, magnesium or fiber-reinforced plastics) can be securely connected by means of the casting knot in a subframe with rigidity and weight optimization. In addition, functional integration and the elimination of components reduce manufacturing costs, costs and weight compared to conventional subframes. The described casting knot may for example consist of a cast iron, magnesium casting or a cast aluminum.

Advantageous developments and improvements of the subframe according to the invention are specified in the subclaims.

An advantageous embodiment of the subframe provides that the side member attachment point and / or the cross member attachment point protrudes from the casting node. This has the advantage that the cross member and / or the longitudinal member can be securely connected to the corresponding attachment point of the casting node. The outstanding connection point also ensures good accessibility to the connection point. This facilitates the assembly of the subframe. In addition, possible welding operations can be carried out more easily and quickly.

Another particularly advantageous embodiment of the subframe provides that the side member attachment point and / or the cross member attachment point is hollow or tubular. Under tubular in this case is to be understood not only a circular shape of the cross section of the respective connection point, but rather that the attachment point has an outer wall surface and an inner wall surface. The described embodiment of the connection point has the advantage that the casting node has a lower weight in comparison to a casting node with a massively designed transverse or side member attachment point. With regard to the casting-technical manufacturability, the described embodiment of the connection section offers e.g. in terms of solidification advantages over a massive design.

A further advantageous embodiment of the subframe provides that the longitudinal member and / or the cross member is formed as a hollow profile or as an open profile. Under hollow profile is essentially a profile with a closed cross-section to understand. By contrast, an open profile does not have a shape closed over its circumference. As an example of open profiles L-, T- or U-profiles can be mentioned. The cross member or side member formed by the hollow profile or the open profile can be produced for example by an extrusion process or extrusion. However, forming processes for producing the transverse or longitudinal members are also conceivable. The described embodiment of the cross member or of the longitudinal member has the advantage that it has a very positive effect on the weight and the rigidity of the subframe.

In order to produce a secure connection between the cross member and / or the longitudinal member with the associated connection point of the casting node, provides a further advantageous embodiment of the subframe according to the invention, that the contact surfaces of cross-member attachment point and cross member are at least partially congruent to each other and / or the contact surfaces of side member attachment point and side member are at least partially congruent to each other.

A further advantageous embodiment of the subframe according to the invention provides that the longitudinal member overlaps at least partially with the side member attachment point and / or that the cross member overlaps at least partially with the cross member attachment point. The advantage of this design is that a secure and easy connection between the transverse or longitudinal beam and the casting node can be made. In addition, the overlap facilitates the positioning of the components to each other, which greatly reduces the manufacturing cost.

In order to be able to securely fix the casting node to the cross member or to the longitudinal member, a further advantageous embodiment of the auxiliary frame provides that the cross member attachment point and the cross member and / or the side member attachment point and the side member have an interference fit to each other. By a press fit possible later joining steps can be omitted, whereby the manufacturing cost decreases. If joining operations are nevertheless carried out in the following, the interference fit prevents a displacement of the casting node relative to the transverse or longitudinal beam, so that a repeatable welding operation is possible. Furthermore, a possible gap formation between abutment surfaces of the transverse or longitudinal member and casting node can be prevented, so that a high-quality and re-hollow joint connection can be realized.

A further advantageous embodiment of the subframe according to the invention provides that the longitudinal member is formed at least in its, the longitudinal beam connection point enclosing end portion and / or the cross member at least in its, the cross-member attachment point enclosing end portion triangular. This has the advantage that the accessibility for a welding robot is guaranteed from all sides. The triangular configuration of the cross member also allows a less expensive weld guide compared to a pipe or a square profile, since a robot guide in a plane or particularly long-distance between the vertices of the triangle is possible. Another advantage of a cross-sectionally triangular cross member is that the space available in the vehicle can be better utilized than at a e.g. in cross-section round cross member.

A further advantageous embodiment of the subframe according to the invention provides that the side member is welded to the side member attachment point and / or the cross member with the cross member attachment point and / or mechanically joined. In this way, different materials can be joined technology-appropriate.

For example, a similar connection between a cast aluminum node and an aluminum cross member can be welded, whereas a foreign connection between an aluminum cast node and can be bolted or glued to a steel side member.

The use of friction stir welding offers various advantages with regard to the subframe according to the invention. Friction stir welding, for example, offers the possibility of joining together materials that are susceptible to hot cracking with limited weldability and with low energy input into the material. In addition, by friction stir welding in a welding process relatively large bonding surfaces between the joining partners can be generated. This has a positive effect on the strength of the welded joint. In addition, it has been found that friction stir welding is also suitable for joining types of material combinations (for example, aluminum with an iron alloy). Therefore, a further advantageous embodiment of the subframe provides that the longitudinal member is welded to the side member attachment point and / or the cross member with the cross member attachment point by means of friction stir welding.

A further advantageous embodiment of the subframe according to the invention provides that the cast node has at least one body attachment point and / or a handlebar attachment point and / or a brake pressure line holder attachment point and / or an exhaust system attachment point and / or a stabilizer attachment point. This embodiment of the subframe has the advantage that the cast node as an integral component combines different functions. As a result, different items can be omitted, whereby the cost and the production cost of the subframe can be reduced.

Advantageous embodiments of the invention are shown in simplified form in the drawings and explained in more detail in the following description.

Show it

1 a subframe according to the invention for a motor vehicle,

2a B a three-dimensional illustrated casting node according to the invention from the inside ( 2a ) and from the outside ( 2 B ),

3 a load path and weight optimized casting node according to the invention,

4 exemplary embodiments of the cross member,

5a C shows a casting node according to the invention, shown in a three-dimensional view, with the cross member attached;

6 a further embodiment of a casting node according to the invention with side members.

1 shows the subframe according to the invention 1 , Also referred to as subframe, the front in the direction of travel V front cross member 2 and a rear cross member 3 includes. The front cross member 2 is formed in the present embodiment by an extruded profile. The rear cross member 3 For example, it consists of a front shell element 3 ' and a back shell member connected thereto 3 '' and is eg directly with a seen in the direction of travel left side member 4 and a right side member seen in the direction of travel 5 welded. The shell elements 3 ' . 3 '' and the side members 4 . 5 are made, for example, from formed steel sheets. The front cross member 2 is via a left cast node 6 and a right cast node 7 with the side rails 4 . 5 connected. The cast nodes 6 . 7 For example, consist of a light metal alloy and have a filigree rib-like structure.

Furthermore, in 1 on both sides made of sheet metal holder for brake pressure lines 8th shown, which via a brake pressure plate holder attachment point 9 with the cast node 6 are connected. It is conceivable that the brake pressure line holders 8th integral part of the cast nodes 6 . 7 are.

In addition, the illustrated subframe according to the invention 1 eg a tubular exhaust system holder 10 which is via an exhaust system holder connection point 11 with the left-hand cast node seen in the direction of travel 6 connected is. It is also readily conceivable that the exhaust system holder 10 also via an exhaust gas holder connection point 11 at the right in the direction of travel seen cast nodes 7 is connected. Another embodiment, not shown here, each sees an exhaust system holder attachment point 11 with or without exhaust system holder 10 at the two casting nodes 6 . 7 in front. An integration of the exhaust system holder 10 in the cast nodes 6 . 7 is just as conceivable.

The 2a B show an embodiment of the left casting node according to the invention 6 in three-dimensional orientation. The same is true in mirror image for the right cast node 7 , Referring to the entire frame shows 2a the left cast node 6 seen from an inner view. 2 B shows the same casting node 6 seen from an external view.

The cast node 6 is designed so that its production no slides are required during the casting process. This has the advantage that the casting tool is made simpler and that the casting node 6 can be made faster and cheaper.

The shape of the casting node shown as an example 6 is essentially cup-shaped or trough-like. The trough-like structure of the casting knot 6 consists essentially of a first costal arch 12 and a second rib bow 13 , as well as a tub bottom 14 , where the ribbed arches 12 . 13 extend substantially transverse to the direction of travel and the tub bottom 14 extends substantially in the direction of travel. As in 3 to recognize the ribs arches 12 . 13 and the tub floor 14 for weight reasons and / or to optimize the load path with recesses 15 and / or additional stiffening ribs 16 be provided.

At the ribbed bows 12 . 13 and the tub floor 14 are, for example, the connection points 9 . 11 . 17 . 18 . 19 . 20 . 21 . 22 intended. So has the exemplary casting node 6 over two body attachments 20 , about which the casting node 6 or the subframe 1 eg is fastened by means of screws to a vehicle body. Furthermore, the casting node points 6 two connection points 19 for an upper control arm and / or connection points 17 for a lower wishbone. The connection points 19 for the upper wishbone are designed as a slot, for example, to adjust the wheel position of the motor vehicle.

Further, in 2 B the brake pressure line holder connection point 9 shown in more detail. In this embodiment, the brake pressure line holder attachment point 9 pocket-shaped. This makes it possible that an existing example of a sheet brake pressure line holder 8th , like in the 1 is shown, partially inserted into the bag and connected to this is is t. The connection can be made, for example, by welding, in particular friction stir welding, gluing, riveting, screwing or other connection technologies. The pocket-shaped design of the brake pressure line holder attachment point 9 has the advantage that the brake pressure line holder 8th especially safe with the casting knot 6 can be connected. Another, not shown embodiment of the casting node 6 . 7 provides that the brake pressure line holder attachment point 9 is formed so that this similar to the brake pressure line holder 8th is directly suitable for mounting a brake pressure line and thus completely assumes its function.

Depending on the exhaust system guidance of the motor vehicle, the casting node points 6 . 7 an exhaust system holder attachment point 11 on. In the 2a illustrated exhaust system holder attachment point 11 is, for example, also bag-shaped educated. The inner wall of the exhaust system holder connection point 11 can be executed in different ways. For example, it may have a cylindrical, elliptical or one or more flattened shape. The cylindrical design has the advantage that the in 1 illustrated exhaust system holder 10 freely rotatable and positionable in the exhaust system holder connection point before its final fixation 11 is. The elliptical or flattened shape of the exhaust system holder attachment point 11 has the advantage that the exhaust system holder 10 , which has a corresponding outer surface is prefixed by a positive connection against rotation. As a result, on the one hand facilitates the assembly and on the other hand, an improved power transmission, for example during operation allows.

The connection from the exhaust system holder 10 with the blind hole-shaped exhaust system holder connection point 11 can be done by welding (eg friction stir welding), gluing, bolting or other joining technologies. The round design of the exhaust system holder 10 has the advantage that it can be made inexpensively and easily from a round material. Furthermore, the exhaust system holder 10 Depending on the requirements have a different geometry and thus find flexible for different embodiments of exhaust systems use. Another non-illustrated embodiment of the exhaust system holder 10 provides that this is made of a metal sheet or a tube. It is also conceivable that the exhaust system holder connection point 11 is designed so that this the functions of the exhaust system holder 10 even takes over.

Furthermore, the embodiment of the subframe according to the invention provides 1 a cast node 6 before, which one in 2 B and 3 illustrated stabilizer attachment site 18 having. The stabilizer attachment site 18 has, for example, two attachment points. The attachment points are executed in this embodiment as a through hole with thread and a blind hole with thread. However, it is conceivable that both attachment points are designed as through holes without thread and the stabilizer via a screw-nut combination at the casting node 6 is attached.

In addition, the subframe according to the invention provides 1 for example, a casting node 6 . 7 which longitudinal beam connection points 22 having. As in 2a can be seen, the side member attachment points 22 be executed as screw-on. The attachment points are designed in this example as a blind hole with thread. This in 3 illustrated embodiment of the side member attachment points 22 provides through holes without thread. The side member 4 will in such a case by a combination of screws and nuts at the casting node 6 attached. Alternatively, the side member 4 with the cast node 6 welded (eg friction stir welding) or glued. As in 6 is shown in more detail, is the side member attachment point 22 for example, designed so that this forms a kind of connection section, which from the casting node 6 protrudes. This trained as a connection section side member connection point 22 is advantageously designed so that they at least partially flat on the side rail 4 is applied.

For fastening the front cross member 2 at the casting node 6 , This has a cross-beam connection point 21 on. This crossbar connection point 21 protrudes from the casting node 6 . 7 out. In the illustrated embodiment, the cross member attachment point 21 in its cross section substantially triangular pronounced. With regard to production and weight aspects, it is advantageous that the cross-member attachment point 21 hollow executed. Hollow in this case means that the connection point 21 a blind hole-like opening (pocket) 23 or has a through opening. Nevertheless, it can be useful to cross-beam connection point 21 be executed solid. Further not shown embodiments of the cross-member attachment point 21 also provide a round or polygonal design.

4 shows various embodiments of cross members 2 the subframe according to the invention. 4a shows an embodiment of the cross member 2 which also in 1 and 5 is shown. It is a hollow profile whose cross-section is triangular. The inner surfaces of the profile are designed so that they are at least partially congruent to the in 2 illustrated outer surfaces of the cross member connection point 21 are. Such a cross member 2 can be made for example as an extruded profile.

Another in 4b illustrated embodiment of a cross member 2 provides that the cross section is substantially triangular with a curved side. The curvature may be advantageous in terms of available space or in terms of stability.

Another in 4c illustrated embodiment of the cross member 2 provides a V-shaped open profile. Such a one-sided open cross member 2 Can an undercut 24 which has the secure grip on the cross member attachment point 21 should ensure. Other not shown Embodiments of an open cross member 2 provide U-, L- or T-shaped cross sections.

Another embodiment of a cross member 2 is in 4d shown. This cross member 2 has curvatures in its course 25 on. These bends 25 may have advantages in terms of the available space or advantages in terms of stiffness of the cross member. Furthermore, the cross member, as out 4d it can be seen within the profile ribs 26 have, which increase the rigidity of the cross member.

Other embodiments, not shown, of the cross member 2 provide cross sections with strength and weight optimized variable wall thicknesses.

The 5a -c show exemplary detailed views of the connection of a front cross member 2 with a left cast node 6 , The tubular cross member 2 is about the out of the cast node 6 outstanding cross member connection point 21 pushed. The cross member overlaps 2 with the crossbeam connection point 21 partially. Ideally, the cross member 2 and the crossbeam tether 21 Fixed to each other via a press fit. Additionally or exclusively, the cross member 2 and the crossbeam tether 21 welded together, glued or mechanically joined. The weld can ideally be in the lap joint between the cross member 2 and the crossbeam tether 21 by means of friction stir welding.

5b shows exemplified by friction stir welding trained the connecting surfaces 27 between the cross member 2 and the crossbeam tether 21 , Due to the triangular design of the cross member 2 and the crossbeam tether 21 are particularly long one-piece interfaces 27 , Another possible welding technology is the laser beam welding in the lap joint. Furthermore, it is conceivable, the cross member 2 and the crossbeam tether 21 to be connected by inert gas welding. In the present case fillet welds or plug welds are suitable for inert gas welding.

6 shows an example of an alternative embodiment of the connection between the left side member 4 and the left cast node 6 , The cast node 6 , an L-shaped curved longitudinal beam connection point 22 on which from the casting node 6 protrudes. In the connection area is the geometry of the longitudinal member 4 Congruent to the longitudinal member connection point 22 formed. The side member 4 and the side member attachment point 22 are over a connection area 27 connected with each other.

LIST OF REFERENCE NUMBERS

1

 subframe

2

 Cross member in front

3

 Cross member rear

3 '

 front shell element of the rear cross member

3 ''

 rear shell element of the rear cross member

4

 Side member left

5

 Side member right

6

 Casting knot on the left

7

 Casting knot on the right

8th

 Brake pressure line hangers

9

 Brake pressure line holder attachment site

10

 Exhaust systems Holder

11

 Exhaust system Holder attachment site

12

 first rib bow

13

 second costal arch

14

 Wannenboden

15

 recess

16

 stiffening rib

17

 Connection point lower wishbone

18

 Stabilizer attachment site

19

 Connection point upper wishbone

20

 Body attachment site

21

 Cross member connecting point

22

 Longitudinal support connecting point

23

 Pocket cross member connection section

24

 Cross member undercut

25

 curvature

26

 Cross member ribbing

27

 interface

V

 direction of travel

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102011012118 A1 [0002]

Claims (11)

Subframe ( 1 ) for a motor vehicle comprising - at least two longitudinal members extending substantially in the direction of travel ( 4 . 5 ), - at least two transversely extending substantially transverse to the direction of cross member ( 2 . 3 ), - at least one casting node ( 6 . 7 ), which a longitudinal beam ( 4 . 5 ) and a cross member ( 2 ), characterized in that the casting node ( 6 . 7 ) a longitudinal beam connection point ( 22 ) and / or a cross-member connection point ( 21 ) having. Subframe ( 1 ) according to claim 1, characterized in that the side member attachment point ( 22 ) and / or the crossbar attachment point ( 21 ) from the casting node ( 6 . 7 ) stands out. Subframe ( 1 ) according to one of claims 1 or 2, characterized in that the side member attachment point ( 22 ) and / or the crossbar attachment point ( 21 ) is hollow or tubular. Subframe ( 1 ) according to one of claims 1 to 3, characterized in that the longitudinal member ( 4 . 5 ) and / or the cross member ( 2 ) is designed as a hollow profile or as an open profile. Subframe ( 1 ) according to one of claims 1 to 4, characterized in that the contact surfaces of the cross-member attachment point ( 21 ) and cross beams ( 2 ) are at least partially congruent to one another and / or that the contact surfaces of side member attachment point ( 21 ) and side members ( 4 . 5 ) are at least partially congruent to each other. Subframe ( 1 ) according to one of claims 1 to 5, characterized in that the longitudinal member ( 4 . 5 ) at least partially with the side member attachment point ( 22 ) overlaps and / or that the cross member ( 2 ) at least partially with the cross-member attachment point ( 21 ) overlaps. Subframe ( 1 ) according to one of claims 1 to 6, characterized in that the cross-member attachment point ( 21 ) and the cross member ( 2 ) and / or the longitudinal member attachment point ( 22 ) and the side member ( 4 . 5 ) have an interference fit with each other. Subframe ( 1 ) according to one of claims 1 to 7, characterized in that the longitudinal member ( 4 . 5 ) at least in its, the longitudinal member attachment point ( 22 ) enclosing end portion and / or the cross member ( 2 ) at least in its, the cross-member attachment point ( 21 ) enclosing end portion is triangular. Subframe ( 1 ) according to one of claims 1 to 8, characterized in that the longitudinal member ( 4 . 5 ) with the longitudinal member attachment point ( 22 ) and / or the cross member ( 2 ) with the crossbeam attachment point ( 21 ) is welded and / or mechanically joined. Subframe ( 1 ) according to one of claims 1 to 9, characterized in that the longitudinal member ( 4 . 5 ) with the longitudinal member attachment point ( 22 ) and / or the cross member ( 2 ) with the crossbeam attachment point ( 21 ) is welded by friction stir welding. Subframe ( 1 ) according to one of claims 1 to 10, characterized in that the casting node ( 6 . 7 ) at least one body attachment point ( 20 ) and / or a handlebar connection point ( 17 . 19 ) and / or a brake pressure line holder attachment point ( 9 ) and / or an exhaust system holder connection point ( 11 ) and / or a stabilizer attachment site ( 18 ) having.

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