Load-bearing optimization through shell on backrest structure with airbag unit

Abstract

The invention relates to a seat back structure for a vehicle seat, comprising a left and a right side element (1) which are connected by an intermediate transverse connection structure, wherein a respective cross-sectional profile of the left and the right side element (1) forms a longitudinal leg (3) and a transverse leg (4), wherein the longitudinal leg (3) and the transverse leg (4) form a concave indentation which is oriented outwards towards the sides of the seat, so that the left and the right side element (1) form recesses pointing away from each other, wherein a recess of at least one side element (1) has a shell (6) which serves to receive an airbag unit (5), and wherein the shell (6) is connected to its side element (1) in a load-bearing manner, so that the shell (6) forms a load-bearing structural element of the seat back structure.

Description

The invention relates to a seat back structure for a vehicle seat, as well as a vehicle seat with such a seat back structure. It is common practice to install airbags in vehicles such as passenger cars. These airbags deploy in an accident, fill with gas, and, through their cushioning effect and volume, are designed to protect the vehicle occupant from serious injuries. While older vehicles typically only had front airbags, newer vehicles also commonly feature side and center airbags. Side and center airbags have had to be made increasingly larger to meet rising safety standards. The airbags are conveniently mounted laterally on the seatback frame and extend across the vehicle. By incorporating recesses to accommodate the airbag units, attempts can be made to keep the installation space within certain limits, while still meeting fatigue strength and crash test requirements. However, the installation of an airbag unit can increase the overall seat width.This in turn leads to installation space problems, especially in relation to surrounding components and functions, up to and including a necessary, but undesirable, widening of the vehicle. In this context, DE 10 2023 003 379 A1 relates to a vehicle comprising a vehicle seating arrangement with a first vehicle seat and a second vehicle seat arranged side by side in the transverse direction of the vehicle, wherein an airbag is arranged in the first vehicle seat on a side facing the second vehicle seat, wherein a foam insert is arranged in the second vehicle seat in a backrest side bolster facing the first vehicle seat and, at least substantially, at the level of the airbag, which is harder than any remaining foam of the backrest side bolster, wherein the geometric dimensions of the foam insert correspond, at least substantially, to the geometric dimensions of an airbag cover for the airbag in the first vehicle seat and / or correspond at most to the size of the backrest side bolster. The object of the invention is to create a seat back structure for a vehicle seat which allows a space-saving arrangement of an airbag unit for a sidebag or midbag and thus avoids, as far as possible, a widening of the vehicle seat for the installation of the respective airbag unit. The invention is defined by the features of the independent claims. Advantageous further developments and embodiments are the subject of the dependent claims. A first aspect of the invention relates to a seat back structure for a vehicle seat, comprising a left and a right side element which are connected to each other by an intermediate transverse connection structure, characterized in that a respective cross-sectional profile of the left and the right side element forms a longitudinal leg and a transverse leg, wherein the respective longitudinal leg is oriented substantially perpendicular to a plane of the seat back structure and the respective transverse leg extends in the plane of the seat back structure and along a transverse direction between the side elements, wherein the longitudinal leg and the transverse leg are arranged at an angle to each other and together form a concave indentation, wherein the concave indentation is oriented away from the transverse connection structure and opens outwards towards the sides of the seat.so that the left and right side elements form recesses pointing away from each other, wherein a recess of at least one side element has a shell that serves to receive an airbag unit, and wherein the shell is connected to the side element in a load-bearing manner, so that the shell forms a load-bearing structural element of the seat back structure. Compared to a conventional seat back structure, the seat back structure according to the invention is adapted, at least in the area of ​​its side elements. The side elements form lateral structural flanks of the seat back structure, which are connected to each other by a cross-connection structure. The plane of the seat back structure is formed by the cross-connection structure and the lateral flanks (formed by the side elements). The plane of the seat back structure thus forms a surface against which the occupant can lean their back on the vehicle seat. Typically, such side elements are angled, so that in a cross-section of a sectioning plane perpendicular to the plane of the seat back structure, a transverse leg and a longitudinal leg appear for each side element in the section view. The longitudinal leg and the transverse leg are not discrete legs of a respective side element; rather, the appearance of a transverse leg and a longitudinal leg arises when the respective side element is viewed in an imaginary cross-section. While for structural reasons and designs, particularly with regard to stiffness, an L-shaped profile is typically used for the side elements in the prior art, wherein the L-shaped profile is formed by the transverse leg and the longitudinal leg and the respective L is directed concavely inwards towards the cross-connection structure, according to the invention the shape of the L is mirrored and the concave indentation is directed outwards and away from the cross-sectional profile, so that a concave indentation is available on the respective side flanks of the seat line structure. This, in turn, allows the housings for the airbag units to be recessed deeper into the seat back structure, eliminating the need to widen the vehicle seat when using airbag units mounted on the outer sides of the seat back structure. This results in an improved design for the basic seat back structure. Space constraints related to surrounding vehicle components, such as the B-pillar or center console, as well as issues with other functions like front airbag deployment, are avoided. Furthermore, this design opens up more possibilities for the stylistic design of the vehicle seat. Inverting the orientation of an L-shaped side element known from the prior art can potentially lead to structural disadvantages. For example, under increased operational or crash conditions, conventional local stiffening measures, such as sheet metal doubling, cannot be used to reinforce the recess required for mounting the airbag unit, as construction restrictions prevent this. However, by designing the shell as a load-bearing component of the seat back structure and at least partially absorbing the loads occurring in the side element, the shell effectively stiffens the seat back structure. Therefore, sheet metal doubling of the side element is unnecessary. Preferably, the shell, as an optimally load-bearing component, is designed as a sheet metal half-shell instead of being made of plastic.The load-bearing shell creates a closed profile, ensuring that forces from operational or crash loads are absorbed and transferred more effectively. Despite the shell's attachment to a side element, the aforementioned advantage is achieved: the installation space in the vehicle's transverse direction is not increased, even when an airbag unit is mounted on the side of a seat backrest. According to an advantageous embodiment, the left and right side elements extend from a pivot axis for tilting a seat back with the seat back structure into different backrest angles to a connection area of ​​the seat back of a headrest. This pivot axis allows the seat back to be adjusted to various reclining angles. At the opposite end of the seat back is a connection point for a headrest. In this embodiment, the respective side element extends over the entire height of the seat back, that is, from the pivot axis for tilting the seat back to the upper end where the connection point for the headrest is located. In other words, at any height along the seat back between the pivot axis and the connection point for the headrest, the side element has a cross-sectional profile with a longitudinal leg and a transverse leg. Together, these legs form the concave recess into which an airbag unit can be inserted. According to a further advantageous embodiment, the respective cross-sectional profile extends from a pivot axis for tilting a seat back with the seat back structure into different backrest angles to a connection area of ​​the seat back of a headrest. According to another advantageous embodiment, the shell is a sheet metal half-shell. According to a further advantageous embodiment, the shell is spaced at least section by section from the side element on which the shell is arranged. According to a further advantageous embodiment, the longitudinal leg and the transverse leg form an angle between 30° and 110° in the area of ​​the concave indentation, preferably between 45° and 90°, particularly preferably between 66° and 90°. According to another advantageous embodiment, the left and right side elements are each designed as sheet metal parts. According to a further advantageous embodiment, one end of the longitudinal leg and / or one end of the transverse leg is roll-formed. According to a further advantageous embodiment, the respective longitudinal leg has no embossing. Rather, such embossing is a theoretically feasible approach for forming a recess in a side structural element according to the prior art, the naturally concave recess of which is formed between a steering leg and a transverse leg and is aligned with the transverse connection structure. The design according to the invention differs from such a design of the side structural element in that the transverse leg is oriented from the longitudinal leg towards the sides of the seat and thus projecting away from the transverse connection structure, instead of, as in the prior art, the transverse legs being aligned with each other along the transverse direction and oriented from the respective longitudinal leg towards the center of the seat back. Another aspect of the invention relates to a vehicle seat with a seat back structure as described above and below, wherein a shell with an airbag unit is arranged in a concave bulge of a side element. According to another advantageous embodiment, the airbag unit is arranged on the shell by screwing or riveting. Advantages and preferred further developments of the proposed vehicle seat result from an analogous and meaningful transfer of the above statements made in connection with the proposed seat back structure. Further advantages, features and details will become apparent from the following description, in which - possibly with reference to the drawing - at least one embodiment is described in detail. Figure 1 shows a vehicle seat in a perspective view with a seat back structure according to an embodiment of the invention. Figure 2 schematically shows the longitudinal and transverse legs of a respective side element as shown in a section plane, according to the prior art. Figure 3 schematically shows the longitudinal and transverse legs of a respective side element as shown in a section plane, according to an embodiment of the invention. Figure 4 shows an airbag unit in a shell in a concave recess formed by the longitudinal and transverse legs, according to an embodiment of the invention. Figure 5 shows a structural variation of the longitudinal and transverse legs of Figure 3 according to a further embodiment of the invention. The representations in the figures are schematic and not to scale. Fig. 1 shows an unpadded basic structure of a vehicle seat, a seat back structure, and an associated seat structure for a seat cushion. The perspective view reveals a right side element 1 and at least a partial left side element 1. For clarity, only the right side element 1 is marked by two curly brackets and with a double reference numeral. The right side element 1, as designated, extends from a pivot axis of the seat back structure for tilting the backrest of the vehicle seat to an upper end of the seat back structure, where a headrest is mounted. The two side elements 1 are connected to each other by a cross-connection structure, which is visible in the view of Fig. 1, at least in the connection area of ​​a headrest (not shown). Furthermore, Fig.Figure 1 shows a planar coordinate system fixed to the seat back structure, with an x-direction in the longitudinal direction and a y-direction in the transverse direction. Accordingly, in Figure 1, the view focuses primarily on a side flank of the right side element 1, which forms a longitudinal leg 3 in cross-section. See Figure 3 for further details. A shell 6 is arranged in the concave recess of the right side element 1 of the seat structure shown, and is attached to the right side element 1 in a load-bearing capacity. The shell 6 serves to accommodate an airbag unit 5, which is not shown in Figure 1 for better visibility. While the right side element 1 is already made of sheet metal, the shell 6 is also made of sheet metal and forms a half-shell. The shell 6 is attached to the right side element 1 in a load-bearing capacity, for example by screwing, riveting, welding, bonding, or other methods.While the recess opens outwards, this shell 6 at least partially closes the resulting open cross-section and therefore offers structural advantages for the load-bearing capacity of the seat back structure. While in Fig. 1 the shell 6 is arranged on a right side element 1 as an example, the seat back can be constructed essentially symmetrically with respect to the side elements 1 and may include another shell 6 in a recess of the left side element 1. Fig. 2 shows a cross-sectional view of a prior art arrangement of a right side element 1 and a left side element 1, wherein each side element 1 forms a transverse leg 4 and a longitudinal leg 3 in section. Furthermore, Fig. 2 indicates a coordinate system whose orientation corresponds to that shown in Fig. 1. A characteristic feature of this prior art arrangement is the two opposing transverse legs 4. The indentation indicated in the drawing is achieved here by an embossing. However, this does not affect the leg arrangement between the longitudinal leg 3 and the transverse leg 4. Fig. 3, however, shows a schematic cross-sectional view of a seat back structure according to the invention. In contrast to the prior art arrangement of Fig. 2, the arrangement of Fig. 3 according to the invention is modified at the side elements 1. Here, the transverse legs 4 point away from each other and thus towards an outer side of the seat back structure, while the longitudinal legs 3 remain unchanged, pointing in the x-direction of the vehicle seat back structure. In this example, a transverse leg 4 with a corresponding longitudinal leg 3 of a side element 1 forms a concave indentation by means of an angle of ninety degrees. The concave indentation, which projects outwards from the transverse connection structure and opens towards the sides of the seat, allows the integration of airbag units 5 into the seat back with such a seat back structure, as shown in the example of Fig. 4 using an exemplary left side element 1. Fig. 4 shows one of the side elements 1, with an airbag unit 5 inserted into the shell 6. Fig. 5 shows a variation of the side elements 1 of Fig. 3, wherein in this example of Fig. 5 at least the longitudinal legs 3 and the transverse legs 4 have roll forming at their ends. In addition, a longitudinal leg 3 forms an angle of less than ninety degrees with a corresponding transverse leg 4, whereby the shell 6 is partially spaced from the longitudinal leg 3 and thus provides better reinforcement of the seat back structure. However, the roll forming and the reduced angle of less than ninety degrees can also be implemented individually, as they represent independent embodiments. Although the invention has been further illustrated and explained in detail by means of preferred embodiments, the invention is not limited by the disclosed examples, and other variations can be derived from them by a person skilled in the art without departing from the scope of protection of the invention. It is therefore clear that a multitude of possible variations exist. It is also clear that the embodiments mentioned as examples are truly only examples and are not to be understood in any way as limiting, for example, the scope of protection, the possible applications, or the configuration of the invention.Rather, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete terms, whereby the person skilled in the art, with knowledge of the disclosed inventive concept, can make various changes, for example with regard to the function or the arrangement of individual elements mentioned in an exemplary embodiment, without leaving the scope of protection defined by the claims and their legal equivalents, such as further explanations in the description. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature DE 10 2023 003 379 A1

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Claims

Seat back structure for a vehicle seat, comprising a left and a right side element (1) which are connected to each other by an intermediate transverse connection structure, characterized in that a respective cross-sectional profile of the left and the right side element (1) forms a longitudinal leg (3) and a transverse leg (4), wherein the respective longitudinal leg (3) is oriented substantially perpendicular to a plane of the seat back structure and the respective transverse leg (4) extends in the plane of the seat back structure and along a transverse direction between the side elements (1), wherein the longitudinal leg (3) and the transverse leg (4) are arranged at an angle to each other and together form a concave indentation, wherein the concave indentation is oriented away from the transverse connection structure and opens outwards towards the sides of the seat, so that the left and the right side element (1) form recesses pointing away from each other.wherein a shell (6) is arranged on a recess of at least one side element (1) which serves to receive an airbag unit (5), and wherein the shell (6) is connected to the side element (1) in a load-bearing manner, such that the shell (6) forms a load-bearing structural element of the seat back structure. Seat back structure according to claim 1, wherein the left and right side elements (1) extend from a pivot axis for tilting a seat back with the seat back structure into different backrest angles to a connection area of ​​the seat back of a headrest. Seat back structure according to claim 2, wherein the respective cross-sectional profile extends from a pivot axis for tilting a seat back with the seat back structure into different backrest angles to a connection area of ​​the seat back of a headrest. Seat back structure according to one of the preceding claims, wherein the shell (6) is a metal sheet half-shell. Seat back structure according to one of the preceding claims, wherein the shell (6) is spaced at least sectionally apart from the side element (1) on which the shell (6) is arranged. Seat back structure according to one of the preceding claims, wherein the longitudinal leg (3) and the transverse leg (4) form an angle between 66° and 90° in the area of ​​the concave indentation. Seat back structure according to one of the preceding claims, wherein the left and right side elements (1) are each designed as sheet metal parts. Seat back structure according to one of the preceding claims, wherein one end of the longitudinal leg (3) and / or one end of the transverse leg (4) is roll-formed. Vehicle seat with a seat back structure according to one of the preceding claims, wherein a shell (6) with an airbag unit (5) is arranged in a concave recess of a side element (1). Vehicle seat according to claim 9, wherein the airbag unit (5) is arranged on the shell (6) by screwing or riveting.

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