Side longitudinal beam unit of a chassis of a multi-axle motor vehicle

Abstract

Lateral longitudinal member unit (10) of a chassis of a multi-axle motor vehicle, comprising a longitudinal member (12) made of at least one web plate (14) which, in an installed state, extends substantially in a transverse direction (42) and a straight-ahead direction of travel (44) of the motor vehicle, characterized by a plurality of L-profile-shaped reinforcing elements (28, 30, 32, 34) which are each firmly connected to the at least one web plate (14) such that at least one profile side (36) of the profile sides (36, 38) is arranged in parallel to the web plate (14), and the other profile side (38) of the profile sides (36, 38) is vertically aligned in a plane arranged perpendicular to the straight-ahead direction of travel (44) in the installed state, wherein edges of the profile side (36) are each provided with a plurality of indentations and protrusions, and wherein at least one of the reinforcing elements (28, 30, 32,34) has at least one fastening element (40) defined by its shape.

Description

[0001] The invention relates to a side member unit of a chassis of a multi-axle motor vehicle according to the preamble of claim 1, comprising a longitudinal member made of at least one web plate. The invention further relates to a chassis of a multi-axle motor vehicle according to the preamble of claim 9 with such a side member unit.

[0002] The invention most closely related to DE 10 2015 218 413 A1 discloses a body structure for a vehicle, in particular a commercial vehicle, with at least one elongated support with a cross-section at least U-shaped, which has a support base and support walls raised thereon, and in which a reinforcing element is inserted at a load application point, the reinforcing element having a cross-section at least U-shaped with a reinforcing element base and reinforcing element walls raised thereon, which can be connected on the inside of the support to the support base and to the support walls respectively, wherein the reinforcing element is made up of at least two parts from angle profile sections, which on the support base side each have a first profile leg and a second profile leg, which are in an overlapping connection to form the reinforcing element base, in which the first profile leg overlaps the second profile leg.which is arranged in a three-layer structure between the first profile leg and the beam base. The first profile leg, which overlaps the second profile leg, has a base section that is in contact with the beam base of the beam.

[0003] DE 10 2010 018 691 A1 proposes a device for improving personal protection in a vehicle, in particular a motor vehicle, in the event of a frontal crash.Essentially, it is provided that, by means of longitudinal member structure sections designed in a certain way and having different deformation resistances of a front longitudinal member structure, in the event of a crash (frontal crash) and while the restraint system assigned to the vehicle occupant travels a response path within a "belt slack", the vehicle can initially be decelerated to such an extent that, in view of the state of the art, a premature coupling of the vehicle occupant to the restraint system can be effected, and that immediately thereafter the force level of at least one of the longitudinal member structure sections can be reduced to a certain lower value in such a way that the vehicle is decelerated to a relatively lesser extent until the maximum forward displacement of the vehicle occupant is reached, so that with reduced loading, in particular of the chest of the vehicle occupant, the occupant is coupled to the restraint system for a longer period of time.

[0004] DE 10 2006 036 455 A1 discloses a longitudinal member for a motor vehicle body, which has a reinforcing element arranged horizontally in a curved section of a tubular support member. The reinforcing element is directly connected to the highest point of a lower horizontal leg of the tubular support member and extends to an upper horizontal leg of the tubular support member.

[0005] DE 10 2004 021 553 A1 discloses a longitudinal member, in particular of a passenger vehicle, in particular a rear longitudinal member, consisting of carrier profiles connected to one another to form a hollow member, forming a closed outer surface, and an inner reinforcement profile located within the carrier cavity and connected to the carrier profiles. The inner reinforcement profile is designed as a profile composed of at least two individual profiles.

[0006] DE 1 862 678 U discloses longitudinal beams which have inserts made of angle profiles on the upper and lower flanges and which are welded to the longitudinal beams.

[0007] In the field of automotive engineering, it is known to change the properties of a motor vehicle by adding additional components, both during production and subsequently.

[0008] For example, US Patent 6,412,853 B1 provides a vehicle drag reduction system using vents, which includes at least one air flap strip. Such an air flap strip has a top, a bottom, and a perimeter formed between them. The air flap strip further includes a coupling device to allow the air flap strip to be coupled to a vehicle body. A plurality of lamellar tabs are also provided, each with a long side edge integrally connected to the air flap strip. Each lamellar tab extends upward and rearward, forming an acute angle with respect to the plane in which the air flap strip is located.

[0009] Furthermore, the modification of motor vehicle sills is known in the art. Sills are typically located on both sides between the wheel arches of a two-axle motor vehicle below the door entry and are aligned parallel to the straight-ahead direction of travel of the vehicle.

[0010] For example, CN 106 080 785 A proposes a solution for attaching a car door sill to a vehicle frame, where the car door sill and the vehicle frame are made of different materials or where conventional fastening methods are not applicable.

[0011] CN 106 080 785 A describes a car door sill with a door sill support. The door sill support is rigidly mounted on a frame of an automobile that supports a battery pack. The car door sill includes a mounting assembly located in the door sill support. The mounting assembly includes a support plate and several installation nuts. The installation nuts are installed at equal intervals along the length of the support plate on one side of the support plate, with the other side of the support plate resting against the door sill support. The support plate and the door sill support each have through holes that correspond one-to-one to the installation nuts. The through holes are used to insert bolts that match the mounting nuts. This solution enables easy installation of the car door sill.

[0012] Other characteristics of a motor vehicle that can be changed by attaching additional components are the external appearance and the corrosion resistance in the area of ​​the vehicle sills.

[0013] US 6 077 576 A proposes an end trim for a sill flange made from an elongated strip of material with a plurality of openings by means of which it can be attached to the sill flanges of a vehicle to provide both a decorative and a protective cover therefor. The end trim may also include lights connected to or incorporated therein. An edge trim forming an end trim may preferably be formed in a universal U-shape, V-shape, single-curve shape, L-shape, or as a partial circle. The edge trim preferably consists of an elongated strip of metal or plastic, which can vary in length and width depending on the vehicle to which it is to be applied.

[0014] Furthermore, it is known in the prior art to increase the strength of vehicle sills by additional components.

[0015] A solution aiming to provide a support structure for a vehicle that offers sufficient structural strength to allow the installation of a convertible roof or removable roof elements is described in US 4,493,506 A. The support structure can also be retrofitted to an existing vehicle.

[0016] The support structure includes a first support member disposed beneath and secured to the underside of a vehicle rocker panel. In one embodiment, a portion of the first support member extends laterally outward from the vehicle rocker panel and is secured to an outer vertical portion of the vehicle rocker panel. A decorative element is secured to the side of the vehicle and configured to overlap a portion of the first support member. A second support member may be secured to the inside of the vehicle rocker panel to increase the structural strength of the support structure.

[0017] A solution to increase the strength of sill structures that are improved in terms of ground effect and aerodynamic properties and therefore have a larger overall configuration is proposed in US Pat. No. 8,480,167 B2. This takes into account that the sills are intended to withstand the standing weight of a vehicle occupant.

[0018] The solution comprises a rocker panel assembly for attachment to a vehicle, consisting of a rocker panel body, a first end feature located at one end of the rocker panel body, and a second end feature located at the other end of the rocker panel body. The rocker panel assembly may be injection molded. The rocker panel body has an outer surface, generally convex, and an inner surface, generally concave. The outer surface of the rocker panel body extends outward from the vehicle to form an outboard section with a predetermined profile based on intended aesthetic and performance characteristics.At least one transverse rib is disposed on and integrally formed with the inner surface of the rocker body, the transverse rib being oriented generally perpendicular to a longitudinal axis of the rocker body. The rocker body has a wall structure with increased thickness in the region proximate the transverse rib. The arrangement of transverse ribs can take a variety of forms, including, but not limited to, a full transverse rib, a full transverse rib with a cutout, and a partial transverse rib.

[0019] Given the state of the art shown, there is still room for improvement in the area of ​​chassis for multi-axle motor vehicles.

[0020] The invention is based on the object of providing a side longitudinal member unit, in particular a rear side longitudinal member unit, of a multi-axle motor vehicle, which has improved properties with regard to strength and, at the same time, low weight as well as simplified manufacturability and high ease of assembly.

[0021] The problem is solved with a side longitudinal beam unit having the features of claim 1 and with a chassis having the features of claim 9.

[0022] A side longitudinal member unit of a chassis of a multi-axle motor vehicle is shown, comprising a longitudinal member made of at least one web plate which, in an installed state, extends essentially in a transverse direction of the vehicle and in a straight-ahead direction of travel of the motor vehicle, and which is characterized by a plurality of L-profile-shaped reinforcing elements which are each firmly connected to the at least one web plate such that at least one profile side of the profile sides is arranged in parallel to the web plate, and the other profile side of the profile sides is vertically aligned in a plane arranged perpendicular to the straight-ahead direction of travel in the installed state, wherein edges of the profile side are each provided with a plurality of indentations and protrusions, and wherein at least one of the reinforcing elements has at least one fastening element defined by its shape.

[0023] Further, particularly advantageous embodiments of the invention are disclosed in the dependent subclaims.

[0024] It should be noted that the features and measures listed individually in the following description can be combined with one another in any technically reasonable manner and demonstrate further embodiments of the invention. The description further characterizes and specifies the invention, particularly in conjunction with the figures.

[0025] As already stated above, a side member unit of a chassis of a multi-axle motor vehicle has a longitudinal member consisting of at least one web plate, which, in an installed state, extends substantially in a vehicle transverse direction and a straight-ahead direction of travel of the motor vehicle, wherein a longitudinal member / web plate can extend in all three vehicle coordinates: longitudinally, transversely, and also in the vertical direction. The side member unit contains a plurality of L-profile-shaped reinforcing elements. The reinforcing elements are each firmly connected to the at least one web plate in such a way that at least one of the profile sides is arranged parallel to the web plate and the other of the profile sides is vertically aligned in a plane perpendicular to the straight-ahead direction of travel in the installed state.Preferably, both profile sides of the modular reinforcement elements are positioned horizontally and vertically in the longitudinal cross-section. Longitudinally, the profile preferably follows the course of the longitudinal beam.

[0026] For the purposes of this invention, a "motor vehicle" shall be understood to mean, in particular, a passenger car, a truck, a semi-trailer truck, or a bus. The term "plurality" shall, for the purposes of this invention, be understood to mean, in particular, a number of at least one.

[0027] The invention makes it possible to provide a side member unit that can offer maximum strength while simultaneously being lightweight. The reinforcement elements of the plurality of reinforcement elements can be used in a modular manner according to predetermined requirements, whereby the side member can be used as a substantially unaltered base element in various applications with different requirements.

[0028] Furthermore, the proposed side-mounted longitudinal beam unit avoids disadvantages that can arise from the use of conventional manufacturing processes to achieve the required strength, such as hot forming processes. These disadvantages include increased susceptibility to corrosion, reduced dimensional accuracy of the final product, and high costs. The invention also enables simplified manufacturing with tighter tolerances. Additionally, the use of extra retaining clips for reinforcement is eliminated when using the side-mounted longitudinal beam unit according to the invention, resulting in improved ease of assembly.

[0029] Preferably, the at least one web plate has a U-shaped profile in the plane perpendicular to the straight-ahead direction of travel, at least along a portion of its extent in the straight-ahead direction. At least one reinforcing element of the plurality of reinforcing elements is rigidly connected to the at least one web plate such that both profile sides of the reinforcing element are arranged parallel to the web plate. In this way, variable requirements regarding bending and / or torsional strength can be met with particularly low material usage.

[0030] In preferred embodiments of the side longitudinal member unit, the at least one web plate is equipped with a plurality of contact surfaces. Each of the contact surfaces has a contour that is adapted to the contour of at least one of the profile sides of a reinforcing element of the plurality of reinforcing elements. The firm connection of the reinforcing elements to one of the contact surfaces can simplify the manufacture of the side longitudinal member unit and improve ease of assembly.

[0031] Preferably, the parallel alignment of at least one profile side of at least one of the reinforcing elements occurs without an intermediate layer, i.e., without a sealing element. Nevertheless, the need for additional sealing can be eliminated, and a painting process typically carried out at the end of production can be sufficient to protect the parts from corrosion. This is also because the respective reinforcing element can be individually manufactured to the required reinforcement task and to the existing side longitudinal beam unit, so that the reinforcing element rests virtually without gaps against the contact surface(s).

[0032] In preferred embodiments of the side longitudinal member unit, the fixed connection of at least one of the reinforcing elements to the at least one web plate is designed as at least one integral connection, which can ensure sufficient strength of the connection. The integral connection can preferably be achieved by welding, in particular by spot welding, or by gluing.

[0033] Preferably, a profile side of at least one of the reinforcement elements, which is essentially vertically oriented in a plane perpendicular to the straight-ahead direction of travel in the installed state, faces a vehicle interior if the reinforcement element is firmly connected to the at least one web plate by a profile side. In such configurations, increased protection against splash water and corrosion can be achieved.

[0034] Preferably, a profile side of at least one of the reinforcing elements, which in the installed state is oriented substantially vertically in a plane perpendicular to the straight-ahead direction of travel, extends at least partially within a space enclosed by a U-shaped profile, provided that the reinforcing element has an L-shaped profile at least along part of its extent in the straight-ahead direction of travel. With such a design, a side longitudinal beam unit of the required strength can be provided with a particularly compact structure and low space requirement.

[0035] As mentioned above, at least one of the reinforcement elements has a fastening element defined by its shape. This allows for a particularly lightweight fastening of the side longitudinal beam unit within a chassis or the fastening of other components to the side longitudinal beam unit. Furthermore, it enables exceptionally easy assembly.

[0036] Preferably, the plurality of reinforcing elements is arranged along a predominant portion of the length of the at least one web plate. The term "predominant portion" in the context of the invention is understood to mean, in particular, a portion of more than 50%, preferably more than 60%, and particularly preferably more than 70% of the length of the at least one web plate. In this way, a side longitudinal member unit can be provided in which the improved strength can be converted into a uniform, i.e., better-defined force transmission along the side longitudinal member unit.

[0037] In preferred embodiments of the side longitudinal beam unit, at least one of the properties of the shape, material type, profile thickness, or multiple reinforcing elements varies, as does the number of reinforcing elements, depending on their position along a length of the at least one web plate. Each reinforcing element on a specific side longitudinal beam unit can therefore be individually adapted in terms of its length, material thickness, material type, and / or shape. The material type should be selected to ensure corrosion resistance even in metallic contact. Due to this modularity of the multiple reinforcing elements, various existing strength requirements for the side longitudinal beam unit can be met in a manner optimized with regard to weight, cost, and / or number of parts.

[0038] In a further aspect of the present invention, a chassis of a multi-axle motor vehicle is provided according to claim 9. The chassis is equipped with at least one embodiment of the side longitudinal member unit according to the invention. The advantages described in connection with the proposed side longitudinal member unit are fully transferable to the chassis.

[0039] Preferably, at least one side longitudinal beam unit is arranged in a rear section of the chassis. The relatively higher strength requirements in this section allow for a particularly significant weight reduction.

[0040] The invention is exemplified by an application in the rear side member of a motor vehicle. The subject matter of the invention is conceivable and feasible in a variety of longitudinal, transverse, and vertical applications, as well as diagonally in space, wherever forces are transmitted to a profile without causing it to collapse.

[0041] In principle, the subject matter of the invention can be used in all industrial applications, including aerospace, in which L-, U-, X-shaped round or polygonal profiles are used, so that buckling of the base profiles can be prevented with the help of the modular L-shaped reinforcement elements according to the invention. The shape of the L does not necessarily have to be 90°, i.e. right-angled; any angle can be realized and rounded modular reinforcement elements in a round base profile or reinforcement elements that are at least partially U-shaped along their extension in sections of U-shaped base profiles are also feasible. In the construction industry, for example, versions made of L-shaped structural steel are conceivable, and in the furniture industry L-shaped wooden profiles glued to the main profile.The same applies to plastic strips that can be glued or otherwise attached to an existing main profile made of any material, or even incorporated into the manufacturing process of that main profile.

[0042] Further advantageous embodiments of the invention are disclosed in the dependent claims and the following description of the figures. Fig. 1 a schematic representation of a side longitudinal member unit according to the invention of a chassis of a multi-axle motor vehicle in a plan view.

[0043] Fig. Figure 1 shows a schematic top view of a possible embodiment of a side longitudinal member unit 10 according to the invention for a chassis of a multi-axle motor vehicle. The motor vehicle can be a passenger car, for example an SUV (Sport Utility Vehicle). The side longitudinal member unit 10 is arranged as part of a rear section of the chassis and in a rear right half-space of the chassis. A mirror-image embodiment of the side longitudinal member unit 10 is arranged accordingly in a rear left half-space of the chassis.

[0044] The side longitudinal member unit 10 has a longitudinal member 12 made of a web plate 14. The web plate 14 can be punched from a steel sheet. The web plate 14 extends essentially in a transverse direction 42 of the vehicle and in a straight-ahead direction 44 of the motor vehicle, which in the Fig. 1 is directed to the left. The web plate 14 can have a U-shaped profile along part of its extension in the straight-ahead direction of travel 44, with paired edges running parallel to each other and a cranked area 18. The U-shaped profile can be arranged with the open side of the U-shape facing upwards.

[0045] The longitudinal beam 12 thus has U-shaped side walls 24 projecting upwards at right angles on both its upper and lower sides. Furthermore, the side walls 24 are partially provided with vertically outwardly projecting flanges 26.

[0046] Furthermore, the longitudinal member 12 includes a plurality of through-openings 22, which are arranged in a central region 16 of the web plate 14 or in outer regions of the rectangular folds 26 of the side walls 24, which are designed as tabs 20, and which serve to fasten the longitudinal member 12 within the chassis or to fasten vehicle components to the longitudinal member 12. For reasons of clarity, Fig. 1 only some of the through openings 22 or tabs 20 are provided with reference symbols as an example.

[0047] The side longitudinal beam unit 10 is equipped with a variety of L-profile-shaped reinforcement elements 28, 30, 32, 34. The reinforcement elements 28, 30, 32, 34 can be manufactured, for example, by bending and punching from a steel plate.

[0048] The reinforcing elements 28, 30, 32, 34 are firmly connected to the web plate 14. One profile side 36 of the profile sides 36, 38 of the L-profile of each of the reinforcing elements 28, 30, 32, 34 is arranged parallel to the web plate 14 and without an intermediate layer, i.e. without a sealing intermediate element. The edges of these profile sides 36 are each provided with a plurality of indentations and bulges in order to achieve a desired local strength with a minimum use of material. The other profile side 38 of the profile sides 36, 38 of the L-profile is oriented essentially vertically in a plane arranged perpendicular to the straight-ahead direction of travel 44, so that it can be imagined from the plane of the drawing of the Fig. 1 protrude upwards. These profile sides 38 can have a uniform web width along an extension of the reinforcing elements 28, 30, 32, 34 viewed in the straight-ahead direction of travel 44.

[0049] The profile sides 38 of the L-profile of each of the reinforcing elements 28, 30, 32, 34 are also arranged in parallel to the web sheet 14, namely with one of the side walls 24 each, and without an intermediate layer, i.e. without a sealing intermediate element.

[0050] The substantially vertically oriented profile sides 38 of the reinforcement elements 28, 30, 32, 34 extend within a space enclosed by the U-shaped profile, wherein the profile sides 36 and 38 of the reinforcement elements 28, 30, 32, 34 can be arranged inside and / or outside the longitudinal beam 12.

[0051] In a rear area of ​​the web plate 14, two reinforcing elements 32, 34 are arranged parallel to one of the side walls 24 of the web plate 14. One of the reinforcing elements 34 may have a greater extension than the other reinforcing element 32.

[0052] As from the Fig. 1, the plurality of reinforcing elements 28, 30, 32, 34 are arranged along a predominant portion of the length of the web plate 14 and in particular along an almost complete portion of the length of the web plate. Fig. 1 shows four reinforcing elements 28, 30, 32, 34 as examples. However, more or fewer than the four reinforcing elements 28, 30, 32, 34 shown may be used, although at least one is required.

[0053] The reinforcement elements 28, 30, 32, 34 have shaped fastening elements 40, which are formed as through holes in the reinforcement elements 28, 30, 32, 34. The fastening elements 40 can serve, on the one hand, for guiding and fastening in a punching tool for producing the reinforcement elements 28, 30, 32, 34. On the other hand, the fastening elements 40 can be used to guide and hold the side longitudinal member unit 10 within the chassis or other motor vehicle components on the side longitudinal member unit 10, thereby achieving a high level of ease of assembly.

[0054] The profile sides 38 of the reinforcing elements 28, 30, 32, 34 with uniform web width can in particular be used when the longitudinal beam 12 is bent in a plane that corresponds to the plane of the drawing. Fig. 1 corresponds to absorbing the tensile and compressive forces that occur and to provide mechanical reinforcement of the side longitudinal beam unit 10 for such movements. The profile sides 36 of the reinforcement elements 28, 30, 32, 34, arranged parallel to the web plate 14, serve to absorb tensile and compressive forces that occur when the longitudinal beam 12 bends perpendicular to the plane corresponding to the plane of the drawing. Fig. 1, and provide mechanical reinforcement of the side member unit with respect to the corresponding movements.

[0055] The terms “front” and “rear” used in this application and word forms derived therefrom refer to the straight-ahead direction of travel 44 of the motor vehicle and an installed state of the side longitudinal member unit 10.

[0056] The fixed connection between each of the reinforcing elements 28, 30, 32, 34 and the web plate 14 or its side walls 24 is established by a plurality of material-bonded connections, which may in particular be formed by spot welds. In other embodiments, at least one of the material-bonded connections may also be formed by an adhesive bond.

[0057] Particularly good force transmission and durability of the connection can be achieved with material-bonded connections between the reinforcing elements 28, 30, 32, 34 and the web plate 14 or its side walls 24. In principle, however, other methods for producing a firm connection between one of the reinforcing elements 28, 30, 32, 34 and the web plate 14 or its side walls 24 are also conceivable, for example by means of a screw connection, a rivet connection or by means of a combination of different connection techniques that appear appropriate to a person skilled in the art.

[0058] In the places where the Fig. 1, the web plate 14 is provided with a contact surface (not shown). Each of the contact surfaces has a contour in a plane arranged perpendicular to the straight-ahead direction of travel 44, which contour is adapted to a contour of the profile side 36 of the respective reinforcement element 28, 30, 32, 34. In this way, the web plate 14 and the profile side 36, or the side wall 24 of the web plate 14 and the profile side 38 of the respective reinforcement element 28, 30, 32, 34, lie so closely together that a specially provided seal or gasket is unnecessary.

[0059] In other embodiments, it is also conceivable that the contact surfaces with contours adapted to the reinforcing elements 28, 30, 32, 34 are recessed in the web plate 14 or in its side walls 24. This allows the reinforcing elements 28, 30, 32, 34 to be arranged in the recessed contact surfaces in the web plate 14 and pressed into the contact surfaces in a pressing operation, so that a firm connection between each of the reinforcing elements 28, 30, 32, 34 and the web plate 14 is established by means of a positive and non-positive connection. The contours can be efficiently incorporated into the web plate 14, whereby the web plate 14 is manufactured as a base element and the respective individually required recess is only later incorporated into the web plate once it has been determined in which vehicle the respective web plate is to be mounted.

[0060] By replacing the reinforcement elements 28, 30, 32, 34 with others having at least one modified property, or by changing the number of reinforcement elements 28, 30, 32, 34 having at least one modified property, the side longitudinal member unit 10 can be equipped with reinforcement elements to meet different existing requirements. These properties relate in particular, but are not limited to, a shape, a type of material, and a wall thickness of the profile shape of the reinforcement elements 28, 30, 32, 34. Equipping the side longitudinal member unit 10 with a plurality of reinforcement elements therefore has the characteristics of a modular concept.

[0061] By replacing the reinforcing elements 28, 30, 32, 34 with others having at least one changed property, or by changing the number of reinforcing elements 28, 30, 32, 34 having at least one changed property, the corresponding property of the plurality of reinforcing elements 28, 30, 32, 34 varies depending on a position along the extension length of the web plate 14.

[0062] As is readily apparent to the person skilled in the art, the modularity of the numerous reinforcement elements 28, 30, 32, 34 allows the various existing requirements for the strength of the side longitudinal beam unit 10 to be met in a manner optimized with regard to weight and / or cost and / or number of parts. The longitudinal beam 12 can be used in its unchanged form for the different applications. List of reference symbols: 10 Side member unit 12 longitudinal members 14 web plate 16 Midrange 18 Offset area 20 tabs 22 passage opening 24 side wall 26 chamfer 28 Reinforcing element 30 Reinforcing element 32 Reinforcing element 34 Reinforcing element 36 profile page 38 profile page 40 Fastening element 42 Vehicle transverse direction 44 Straight-ahead direction

Claims

[1] Side longitudinal member unit (10) of a chassis of a multi-axle motor vehicle, comprising a longitudinal member (12) made of at least one web plate (14) which, in an installed state, extends substantially in a vehicle transverse direction (42) and a straight-ahead direction of travel (44) of the motor vehicle, characterized bya plurality of L-profile-shaped reinforcing elements (28, 30, 32, 34), each of which is firmly connected to the at least one web plate (14) in such a way that at least one profile side (36) of the profile sides (36, 38) is arranged in parallel contact with the web plate (14), and the other profile side (38) of the profile sides (36, 38) is aligned vertically in a plane arranged perpendicular to the straight-ahead direction of travel (44) in the installed state, wherein edges of the profile side (36) are each provided with a plurality of indentations and bulges, and wherein at least one of the reinforcing elements (28, 30, 32, 34) has at least one fastening element (40) defined by shaping. [2] Side longitudinal member unit (10) according to claim 1, characterized byin that the at least one web plate (14) has a U-shaped profile in the plane arranged perpendicular to the straight-ahead direction of travel (44) at least along part of its extension in the straight-ahead direction of travel (44) and at least one reinforcing element (28, 30, 32, 34) of the plurality of reinforcing elements (28, 30, 32, 34) is firmly connected to the at least one web plate (14) in such a way that both profile sides (36) of the reinforcing element (28, 30, 32, 34) are arranged in parallel contact with the web plate (14). [3] Side longitudinal member unit (10) according to claim 1 or 2, characterized by in that the at least one web plate (14) is equipped with a plurality of contact surfaces, wherein each of the contact surfaces has a contour which is adapted to a contour of at least one profile side (36) of the profile sides (36, 38) of a reinforcing element (28, 30, 32, 34) of the plurality of reinforcing elements (28, 30, 32, 34). [4] Side longitudinal member unit (10) according to one of the preceding claims, characterized by that the parallel arrangement of the at least one profile side (36) of at least one of the reinforcing elements (28, 30, 32, 34) exists without an intermediate layer. [5] Side longitudinal member unit (10) according to one of the preceding claims, characterized by that the fixed connection of at least one of the reinforcing elements (28, 30, 32, 34) to the at least one web plate (14) is designed as at least one material-to-material connection. [6] Side longitudinal member unit (10) according to one of the preceding claims, characterized byin that a profile side (38) of at least one of the reinforcing elements (28, 30, 32, 34) which, in the installed state, is vertically oriented in a plane arranged perpendicular to the straight-ahead direction of travel (44) faces a vehicle interior when the reinforcing element (28, 30, 32, 34) is firmly connected to the at least one web plate (14) by a profile side (38), and in that a profile side (38) of at least one of the reinforcing elements (28, 30, 32, 34) which, in the installed state, is vertically oriented in a plane arranged perpendicular to the straight-ahead direction of travel (44) extends at least partially within a space enclosed by a U-shaped profile when the reinforcing element (28, 30, 32, 34) has an L-shaped profile at least along part of its extension in the straight-ahead direction of travel (44). [7] Side longitudinal member unit (10) according to one of the preceding claims, characterized bythat the plurality of reinforcing elements (28, 30, 32, 34) are arranged along a predominant portion of an extension length of the at least one web plate (14). [8] Side longitudinal member unit (10) according to one of the preceding claims, characterized by that at least one of the properties of shape, type of material, thickness of the profile shape of the plurality of reinforcing elements (28, 30, 32, 34) and a number of reinforcing elements (28, 30, 32, 34) varies depending on a position along an extension length of the at least one web plate (14). [9] Chassis of a multi-axle motor vehicle, characterized by at least one side longitudinal member unit (10) according to one of the preceding claims.

Images