Spacer element for a subframe for a motor vehicle, subframe and motor vehicle

Abstract

A spacer element for a motor vehicle subframe is proposed, comprising a prismatically designed first through-section and a prismatically designed second through-section, and a connecting section linking the first through-section to the second through-section. Furthermore, a motor vehicle subframe incorporating such a spacer element is proposed. This subframe is characterized by improved connection stiffness for the anti-roll bar on the front axle.

Description

[0001] The invention relates to a spacer element for a subframe for a motor vehicle, a subframe for a motor vehicle and a motor vehicle.

[0002] A subframe is a common component in automotive engineering. The body-side pivot points of the wheel suspension are attached to the subframe, and the assemblies, i.e. the engine, transmission and steering gear, are usually also attached to the front subframe. The subframe can also be referred to as a chassis subframe or axle carrier. The subframe often consists of several components that are joined together during production of the subframe. Such components can, for example, be an upper shell and a lower shell, which, in simple terms, each form an upper half and a lower half of the subframe. When joined together, the result is a complex hollow profile. In most cases, the upper and lower shells are joined together by a material bond, primarily by welding.However, additional connecting elements can penetrate the upper and lower shells in order to attach add-on components to the subframe or the subframe to the bodyshell. To prevent possible deformation of the subframe caused by this, several spacers or standoffs are often arranged between the upper and lower shells. These spacers ensure that the intended shape or distance between the top and bottom of the subframe is maintained. For this purpose, such spacers are designed and dimensioned according to their intended use so that they can absorb the forces acting, particularly in the vertical direction. The spacers are usually sleeve-shaped or tubular.

[0003] In practice, high stiffness values ​​for the subframe are generally advantageous. On the front axle in particular, a multitude of different forces often act simultaneously. These include, for example, drive forces, steering forces and forces introduced by the road surface, e.g., road bumps. Insufficient connection stiffness for the anti-roll bar on the front axle can have a negative impact on the vehicle's controllability in narrow road sections, e.g., when driving through motorway construction zones, as well as negative effects on yaw linearity in the linear lateral acceleration range. Likewise, low connection stiffness is generally detrimental to the intuitiveness of the steering and handling, making it more difficult for the driver to adapt to the vehicle's behavior. It can also have a negative impact on the subjective feeling of driving safety and controllability during maneuvers to avoid accidents.

[0004] It is known from the state of the art to take measures to create various geometries with high rigidity while simultaneously reducing weight. In addition to pure geometry changes, it is also known to provide additional components that are bolted or welded to increase rigidity. These can be struts or similar components, for example. It is also known to use components with high sheet thickness, which, however, are not required to meet fatigue strength requirements. The known options for improving the connection rigidity of the front anti-roll bar are therefore often characterized by high weight and high material costs.

[0005] Special structural designs of the subframe, such as connecting the stabilizer as close as possible to stiffer structures, for example on the tower of the subframe, or implementing the stiffest possible structure of the longitudinal member in the bodyshell, whereby the connection stiffness can be positively influenced by increased stiffness of the subframe and the longitudinal member, are often structurally complex and also cost-intensive.

[0006] EP 3 369 645 B1 discloses a subframe for a motor vehicle, comprising spaced-apart longitudinal members, at least one cross member connecting the longitudinal members, and reinforcing elements connected to the longitudinal members and the cross member and made of sheet metal. The reinforcing elements are composed of a first reinforcing element and a second reinforcing element, which are designed as bent shells and have overlapping ends. The overlapping ends are integrally connected, preferably welded, to the cross member or one of the longitudinal members.

[0007] The solutions known from the state of the art are each characterized by a quite significant additional weight and / or increased costs compared to a subframe without optimizing the stiffness, so that an improvement in the cost-benefit ratio is desirable.

[0008] The object of the present invention is therefore to realize a subframe which has increased rigidity, particularly in a connection area for a transverse stabilizer, and which can be manufactured in a structurally simple manner.

[0009] The problem is solved by a spacer element for a subframe for a motor vehicle, comprising a prismatically designed first passage portion and a prismatically designed second passage portion, and comprising a connecting portion that connects the first passage portion to the second passage portion. The problem is further solved by a subframe for a motor vehicle comprising such a spacer element, as well as by a motor vehicle comprising such a subframe and / or comprising such a spacer element.

[0010] The first spacer element and the second spacer element perform the function of the familiar, sleeve-shaped spacers. They can have one or more cavities extending axially, usually vertically when installed. These cavities are open on the underside and top of the spacer element and extend, in particular, through the respective through-portion. The cavity can then be penetrated by a screw or bolt. The screw or bolt can be provided for attaching a transverse stabilizer to the subframe.The spacer element absorbs forces acting in the axial direction and ensures that a predetermined distance, namely usually the extension of the respective spacer element and in particular of the respective passage portion in the vertical direction, between the first portion of the subframe and the second portion of the subframe is not undercut.

[0011] A prismatic body is understood, in particular, to be a body that has a geometric shape with two mutually parallel and at least substantially congruent end faces and at least one lateral surface extending perpendicular to these end faces. The end faces can, for example, have the shape of a regular polygon, such as a square, a hexagon, or an octagon. However, the end faces can also be elliptical, oval, or circular. In this preferred embodiment, the prismatic base body is then a cylindrical base body.

[0012] According to a preferred embodiment, the first passage portion and / or the second passage portion are cylindrical. Conventional spacers or distance elements are often also cylindrical. The distance element according to the invention can then be used for existing structures without major adaptations. Furthermore, such a cylindrical basic shape offers an advantageous ratio of stability to weight of the distance element.

[0013] It is advantageously possible for the connecting portion to have a rectangular basic shape. The connecting portion is preferably a rigid structure that connects the first passage portion to the second passage portion and can transmit forces between the first passage portion and the second passage portion. If the connecting portion has a rectangular basic shape, the length of a first edge of the rectangular basic shape can correspond substantially or exactly to a height of a passage portion. The length of a second edge of the rectangular basic shape can correspond substantially or exactly to a distance, in particular a distance in the horizontal direction, between the first passage portion and the second passage portion. In particular, the length of the second edge can correspond to a distance between the lateral surfaces of the first passage portion and the second passage portion.The corresponding distance can correspond to the smallest possible distance between the first passage portion and the second passage portion. However, it is also possible for the distance to be greater than this smallest possible distance. In particular, in a preferred embodiment, the length of an edge of the rectangular basic shape of the connecting element can correspond to a distance between the center axis of the first passage portion and the center axis of the second passage portion. In this case, it is possible for the connecting portion to extend tangentially to the lateral surface of the first passage portion and to the lateral surface of the second passage portion.

[0014] The connecting portion can be configured as an at least substantially planar sheet metal portion. It is then particularly possible for the spacer element to be designed as a single piece. In other words, a single metal sheet is used to produce the entire spacer element or at least a basic element of the spacer element, which comprises the first through portion, the second through portion, and the connecting portion.

[0015] According to a preferred embodiment, the spacer element has a first rolled sheet metal section, which forms the first passage portion, and / or a second rolled sheet metal section, which forms the second passage portion. The spacer element can then be produced easily and cost-effectively and, at the same time, has a rigid and strong connection between the first passage portion and the second passage portion. A rolled sheet metal section is understood in particular to mean a sheet metal section that has been formed from a flat shape into a curved shape. A bending radius can be significantly smaller than a length of the sheet and, for example, amount to less than 40%, less than 30%, or less than 20% of the length of the sheet. The bending radius is preferably constant, but can also be variable, resulting in a curved cross-section that deviates from a part-circular cross-section.The bent section can have a center angle of, for example, between 180° and 360°, preferably between 270° and 260°, and particularly preferably between 300° and 350°. In principle, it is also conceivable to roll such a sheet metal section in a spiral shape, which would analogously result in a center angle of more than 360°.

[0016] According to an advantageous embodiment, the connecting portion has a recess. The recess can in particular be arranged at an edge, for example at a lower edge of the connecting portion, and be open towards this edge. In other words, the connecting portion can have a region with reduced extension in the vertical direction. This configuration prevents a component of the subframe or of the motor vehicle running between the first through-passage portion and the second through-passage portion from coming into contact with the spacer element or being disturbed by it. In particular, the free space created by the recess can be partially filled or penetrated by a transverse stabilizer of the motor vehicle.

[0017] A suitable embodiment provides that a first central axis of the first passage portion and a second central axis of the second passage portion are aligned parallel to one another. In a special embodiment, the spacer element can also be designed at least approximately mirror-symmetrically to an axis of symmetry running through the connecting portion. Accordingly, the first passage portion, in particular, can be designed similarly to the second passage portion. This is particularly, but not exclusively, the case when such an axis of symmetry is present.

[0018] It is advantageously possible for the connecting portion to be aligned parallel to a first central axis of the first through-passage portion and / or parallel to a second central axis of the second through-passage portion. The connecting portion can be flat. Accordingly, a first side surface and a second side surface of the connecting portion can be flat. If the connecting portion is designed as a sheet metal element, an upper and a lower edge of the connecting portion can run essentially or exactly horizontally. Accordingly, a third edge and a fourth edge of the connecting portion can run vertically. The third edge can be connected to the first through-passage portion and / or the fourth edge can be connected to the second through-passage portion. It is possible for the third edge and / or the fourth edge to exist merely in the geometric sense as an imaginary boundary of the connecting portion.In particular, if the spacer element is designed as a single piece, the connecting portion can transition seamlessly into the first through-passage element and / or the second through-passage element without forming a physical edge. In other words, it is possible for a circumferential surface of the first through-passage element and / or a circumferential surface of the second through-passage element to transition continuously into a side surface of the connecting portion. Measures can be taken to increase the rigidity and / or reduce the weight of the connecting portion. For example, the connecting portion can have weight-reducing recesses and / or a stiffening bead or beading.

[0019] It is possible for a first central axis of the first passage portion and a second central axis of the second passage portion to run outside a plane determined by a flat section of the connecting portion. In a plan view, the spacer element can have an opera-glass-shaped shape. In this case, the connecting portion can run along a tangent of a lateral surface of the first passage portion and / or the second passage portion. If the connecting portion simultaneously runs parallel to a connecting line between the central axis of the first passage portion and the central axis of the second passage portion, the previously described opera-glass-shaped configuration results. It is also possible for the connecting portion not to run parallel to a connecting line between the central axis of the first passage portion and the central axis of the second passage portion.The connecting section can then intersect this connecting line. In this case, an S-shaped cross-section of the spacer element results when cut parallel to the horizontal plane. If the through sections consist of rolled sheet metal sections, the forming directions of the two end sections are opposite. Thus, one section is bent or rolled toward the front of the sheet, while the other section is bent or rolled toward the back of the sheet.

[0020] It is possible for the first passage portion and / or the second passage portion and / or the connecting portion to consist of a metal sheet or a section of a metal sheet with a thickness of 1 mm to 5 mm, preferably 2 mm to 3 mm. This then results in an advantageous ratio of rigidity, strength and weight. The connecting portion can have a smaller material thickness than the passage portions. Such a configuration has weight advantages over a configuration with a constant material thickness. In an alternative configuration, it is also possible for the connecting portion to have a greater material thickness than the passage portions.

[0021] A preferred embodiment provides that the spacer element is fixed to a part of the subframe with a welded connection. The welded connection can consist of a weld seam, a spot weld, or several spot welds or weld seams. The welded connection can connect a horizontally running side or edge of the spacer element and in particular of the connecting portion to the subframe and in particular to a surface of an element of the subframe. The welded connection can preferably run horizontally. Accordingly, the surface of the element of the subframe to which the connecting portion is connected also usually runs horizontally. The welded connection can be designed as a weld seam of varying lengths.For example, the length of the weld seam may be more than 50% of the length of the connecting section and / or less than 85% of the length of the connecting section. It is also possible for the length of the weld seam to be more than 85% of the length of the connecting section and, in particular, 100% of the length of the connecting section.

[0022] As already indicated above, it is possible for the spacer element to be arranged in a region of the subframe in which a transverse stabilizer bar of the motor vehicle runs when the subframe is installed in a motor vehicle. In this case, it is possible for the first through-passage portion and the second through-passage portion to be arranged on opposite sides of a through-passage region for a transverse stabilizer, as viewed in the direction of travel. It is also possible for an imaginary connecting line between the first through-passage element and the second through-passage element to run parallel to the direction of travel. For example, the imaginary connecting line can be aligned horizontally and connect a central axis of the first through-passage element and a central axis of the second through-passage element.

[0023] Various measures can be taken to achieve weight savings. For example, the through-passage portions and / or the connecting portion can have recesses or hole-shaped cutouts, for example through-bores. Both the through-passage portions and the connecting portion can each have one such recess or a plurality of recesses, for example at least 2, at least 3 or at least 5 recesses. The recesses can, for example, be circular or elongated. If one or both through-passage portions have a recess in the form of an elongated hole or a slot, said recess preferably runs parallel to the central axis of the through-passage portion, which usually corresponds to the vertical. Several elongated holes or slots can be distributed over the circumference of the respective through-passage portion.One or both passage sections can each have one or more horizontal lines running along the circumference of the respective passage section, each with several spaced-apart recesses. In this case, the recesses can also be circular, for example.

[0024] The connecting portion can also have one or more such horizontally extending rows of, for example, circular recesses. Alternatively or additionally, the connecting portion can have a horizontally extending elongated hole or a horizontally extending slot. To increase the rigidity, particularly of the connecting portion, a bead or embossing of the connecting portion can be provided. The bead or embossing can preferably be horizontally aligned.

[0025] Embodiments of the invention are explained in more detail with reference to the drawings and the following description. They show: Fig. 1: a first embodiment of a subframe in a perspective view, Fig. 2: a section of a subframe according to the state of the art, Fig. 3: a section of a first embodiment of a subframe 2 with a spacer element according to the invention in a perspective view, Fig. 4: Parts of the first embodiment in a perspective view, Fig. 5: Parts of the first embodiment in a perspective view, and Fig. 6: a perspective view from below of the first embodiment.

[0026] Fig. Figure 1 shows a first embodiment of a subframe 2 in a perspective view with two spacer elements according to the invention that are not visible in the illustrated view. The subframe 2 consists of three main components, namely the upper shell 4, the lower shell 6 and the body 8. The three main components are each three-dimensionally formed metal parts that are connected to each other and, together with several other three-dimensionally formed sheet metal parts such as tower shells, cross members, etc., form the subframe 2. Furthermore, Fig. 1 shows a transverse stabilizer bar 10, which is connected to the subframe 2. This connection is usually made using clamps that are not visible in the view shown. The dashed areas roughly correspond to the sections shown in the following figures.

[0027] Fig. 2 shows a section of a subframe 2 according to the prior art. This subframe also consists of an upper shell 4 and a lower shell 6. For the sake of clarity, the upper shell 4 and the lower shell 6 are not shown in full in order to reveal details that would otherwise be hidden, for example, by side walls of the upper shell 4 or the lower shell 6. The upper shell 4 and the lower shell 6 are connected to one another at several points by screws, which serve to attach further components to the subframe 2 or to fix the subframe 2 to the bodyshell of the motor vehicle. In the example shown, two screws have been screwed from below through the lower shell 6 into nuts arranged on the upper shell 4. The two spacer elements 12 ensure that the two components to be connected do not fall below the intended distance and that there is no deformation of the upper shell 4 and / or the lower shell 6.The spacer elements 12 are designed as sleeves or tube sections. They are made of metal and have a cylindrical or hollow-cylindrical basic shape.

[0028] Fig. 3 shows a section of a first exemplary embodiment of a subframe 2 with a spacer element 14 according to the invention. The subframe 2 consists, in a known manner, of at least an upper shell 4 and a lower shell 6. In the section shown, the upper shell 4 and the lower shell 6 are traversed by two screws not visible in the figure. The two screws penetrate the spacer element 14. The spacer element 14 has a first cylindrical through-passage portion 16 and a second cylindrical through-passage portion 18, as well as a connecting portion 20. A first end face of each of the first through-passage portion 16 and the second through-passage portion 18 is in contact with a surface of the lower shell 6. On the opposite side, a second end face of each of the first connecting portion 16 and the second connecting portion 18 is in contact with a surface of the upper shell 4 not shown in the figure.Both the upper shell 4 and the lower shell 6 have through holes for the screws at the corresponding points. On a surface of the upper shell 4 opposite the spacer element 14, there are two nuts into which the screws have been screwed. Furthermore, a welded connection 22 is shown, which is designed as a weld seam and connects the spacer element 14 to a portion of the subframe 2. In the illustrated embodiment, this portion connected to the spacer element 14 is an underside of the upper shell 4. The welded connection 22 thus connects an upper edge of the connecting portion 20 to an underside of the upper shell 4.

[0029] Fig. 4 shows the first embodiment in a view analogous to Fig. 3, whereby in this view only the upper shell 4 and a cross-roller 10 are shown. It can be seen that the area in which the spacer element, not visible in this view, is arranged is a box-shaped section 24 of the upper shell 4. On the upper side of the upper shell 4, the two nuts 28 can be seen, into which the screws for connecting the upper shell 4 to the lower shell 6 (not shown) and for mounting the cross-roller 10 are screwed. It can also be seen that the upper shell 4 has a free space 26 in the area of ​​the cross-roller 10, through which the cross member 10 runs. The free space 26 is realized in particular by a part-circular, approximately semicircular recess in the side walls of the box-shaped section 24. The free space 26 between the cross-roller 10 and the upper shell 4 is filled by the geometry of rubber bearings for mounting the cross-roller 10.The clamp (not shown in the figure) for attaching the anti-roll bar 10 to the subframe 2 runs around this rubber geometry. The connecting portion of the spacer element, not visible in the figure, has a similar recess through which the anti-roll bar 10 can pass. The recess in the connecting portion can have a similar shape to the recess in the side wall of the upper shell 4 or be congruent with it.

[0030] Fig. 5 also shows the embodiment from Fig. 4. In this view, however, the upper shell 4 is only partially shown, so that the spacer element 14 is visible. The spacer element 14 rests on its underside, in particular with the lower end faces of the first through-passage portion 16 and the second through-passage portion 18, on an upper side of the lower shell 6. At an upper side or upper edge of the connecting portion 20, the connecting portion 20 is also in contact with the upper shell 4. In this area, a welding area 30 is formed, in which, in the assembled state, the welded connection to a portion of the subframe, in this case to the upper shell 4, is arranged. The connecting portion 20 of the spacer element 14 has an arcuate edge 32 on its downward-facing end face, which makes it possible to provide the previously described free space for the anti-roll bar 10 and its mounting.It can also be seen that the two through sections 16, 18 consist of bent sections of a sheet metal which forms the spacer element 14 and which were brought from a flat shape into the illustrated shape of the spacer element 14 by partially rolling up the end sections. The flat original shape of the sheet metal corresponds to a rectangle with a relatively large aspect ratio. In other words, the length of the long side of the rectangle is several times greater than the length of the short side of the rectangle. The short side of the rectangle corresponds to the height of the spacer element 14 in the installed state. In contrast to a rectangle, the sheet metal in its original shape has a part-circular cutout which, in the formed state, forms the free space with the curved edge 32.

[0031] Fig. Figure 6 shows a perspective view obliquely from below of the previously described embodiment of the subframe 2 with the spacer element 14. In the view shown, only the upper shell 4 is shown, but not the lower shell 6. Furthermore, the upper shell 4 together with the spacer element 14 is shown in comparison to the view in the Fig. 4 and Fig. 5 rotated by 90°. Next to the upper shell 4, the spacer element 14 can be seen, which consists of the first passage part 16 and the second passage part 18 as well as the connecting part 20. The connecting part 20 has the Fig. 5 already described arcuate edge 32. Also visible is the welded connection 22 which connects the connecting portion 20 to a surface of the upper shell 4. The first through-passage portion 16 has a central cavity 34 through which a screw (not shown) runs. Analogously, the second through-passage portion 18 has a central cavity 36 through which a screw (not shown) also runs. It can also be seen that although the through-passage portions 16, 18 basically have a hollow cylindrical basic shape, the outer surface is not completely closed. The through-passage portions 16, 18 therefore each have a gap 38, 40 or slot running in the vertical direction, which creates a free space between the respective end face of an end section of the sheet metal portion from which the through-passage portions 16, 18 were formed, and the respective transition region between the respective first through-passage portion 16 orthe second passage portion 18 and the connecting portion 20.

[0032] All features of various embodiments, which are not logically mutually exclusive, can of course be combined with one another. In the embodiments, the preferred example of a cylindrical design of the base body of the passage portions was described. However, another prismatic basic shape, for example a cuboid base body, is also readily conceivable and offers the same advantages in terms of strength and rigidity as the cylindrical base body. Further modifications are also conceivable. For example, the spacer element 14 can be Fig. 5 shown embodiment rotated by 180° into the subframe 2. In other words, then, compared to the Fig.5, the upper edge and the lower edge of the spacer element 14 are swapped. The curved edge can then point towards the upper shell of the subframe 2. The welding area 30, in turn, can be oriented downwards towards the lower shell 6 in this embodiment. A horizontally running edge of the spacer element 14 can then be in contact with an upper side of the lower shell 6. If this edge has the welding area 30, a material connection, for example a welded connection, can exist between the spacer element 14 and the lower shell. The spacer element 14 can therefore be welded to the subframe 2 and in particular to the lower shell 6 by means of the welding area 30. List of reference symbols 2 subframes 4 upper shell 6 lower shell 8 Corpus 10 Anti-roll bar 12 spacer element 14 Spacer element 16 first passage portion 18 second passage portion 20 connection share 22 Welded joint 24 box-shaped section 26 Clearance for anti-roll bar 28 mother 30 welding area 32 curved edge 34 cavity 36 cavity 38 gap 40 gap QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This 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

[0000] EP 3 369 645 B1

[0006]

Claims

[1] Spacer element (14) for a subframe (2) for a motor vehicle, with a prismatically designed first passage portion (16) and a prismatically designed second passage portion (18), and with a connecting portion (20) which connects the first passage portion (16) to the second passage portion (18). [2] Spacer element (14) according to claim 1, characterized by that the first passage portion (16) and / or the second passage portion (18) is / are cylindrical. [3] Spacer element (14) according to one of the preceding claims, characterized by that the connecting portion (20) is designed as an at least substantially planar sheet metal portion. [4] Spacer element (14) according to one of the preceding claims, characterized by that the spacer element (14) is designed in one piece. [5] Spacer element (14) according to one of the preceding claims, characterized bya first rolled sheet metal section forming the first passage portion (16), and by a second rolled sheet metal section forming the second passage portion (18). [6] Spacer element (14) according to one of the preceding claims, characterized by that a first central axis of the first passage portion (16) and a second central axis of the second passage portion (18) extend outside a plane determined by a flat section of the connecting portion (20). [7] Spacer element (14) according to one of the preceding claims, characterized by that a circumferential surface of the first passage portion (16) and / or a circumferential surface of the second passage portion (18) continuously merges into a side surface of the connecting portion (20). [8] Subframe (2) for a motor vehicle with a spacer element (14) according to one of the preceding claims. [9] Subframe (2) according to claim 8, characterized bythat the spacer element (14) is fixed to a part of the subframe (2) by a welded connection (22). [10] Motor vehicle with a spacer element (14) according to one of claims 1 to 7 and / or with a subframe (2) according to one of claims 8 to 9.

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