LOAD-BEARING STRUCTURAL COMPONENT FOR A VEHICLE SEAT

Description

[0001] The present invention relates to a seat structure of a vehicle seat having the features of the preamble of claim 1.

[0002] Vehicle seats with integrated seat belts are known, for example, for use as front seats in convertibles, where at least the seat belt retractors are mounted in the seat backs. In this case, due to the lack of a load-bearing B-pillar and for reasons of access to the rear seats or distance from the rear vehicle structure, the retractors are preferably integrated into the seat backs, which must therefore also be designed to withstand the tensile forces acting in the event of a restraint. The retractors themselves are identical in their basic design to standard seat belt retractors and are only equipped with various additional components specifically designed for installation in the seat backs, such as a self-aligning inertial sensor.

[0003] The seatbelt retractors consist of a load-bearing frame and a belt spool rotatably mounted within the frame, onto which a seatbelt can be wound. In addition to supporting the belt spool, the frame also serves to attach the retractors to the seat structure and is therefore made of a sufficiently thick sheet of steel bent into a U-shape.

[0004] The basic structure of the vehicle seat consists of several load-bearing structural parts, which serve to attach the vehicle seat to the vehicle structure.

[0005] The seat structure is equipped with springs and padding to improve seating comfort and also serves to attach other components such as various seat adjustment mechanisms, including the associated electric motors and other components such as heating devices, sensors, displays, headrests and the like.

[0006] In modern vehicles with autonomous driving systems, there is an increasing demand for greater adjustability of the vehicle seats to various orientations and positions. This allows occupants to utilize the freedoms gained through autonomous driving, for example, for more in-depth communication with other passengers, extended and more intensive rest periods, or even for work, and to adjust the vehicle seat accordingly. As a result, the seat belt assembly, and in particular the belt retractor, must no longer be attached to the vehicle structure, but instead to the vehicle seat itself, as is already the case, for example, with the front seats in convertibles.

[0007] From German patent application DE 196 16 016 C2, which forms the preamble of claim 1, a seat structure is known with a U-shaped cross member with additional stiffening strips in which two seat belt retractors are arranged. German patent application EP 0 689 957 A1 also discloses a seat structure according to the preamble of claim 1.

[0008] From the publication DE 10 2012 022 159 A1, a backrest structure of a vehicle is known which has a base plate with a mounting slot in which a belt retractor can be attached.

[0009] Against this background, the invention is based on the objective of providing an improved seat structure with a fastening of a belt retractor that is as space-saving and dimensionally stable as possible.

[0010] To solve the problem, a seating structure with the features of claim 1 is proposed. Further preferred developments of the invention can be found in the dependent claims, the figures, and the accompanying description.

[0011] According to the basic concept of the invention, claim 1 proposes a seat structure of a vehicle seat with a backrest having two longitudinal struts aligned parallel to each other and a load-bearing structural element connecting the upper ends of the longitudinal struts to form a dimensionally stable upper surface of the backrest. The structural element has a cavity in which the seatbelt retractor is arranged. The load-bearing structural element comprises a profile rail open on one side with two opposing legs extending from a base surface. The cavity is formed by the space between the opposing legs, and the profile rail is completed by a cover element to form a closed profile. The proposed solution creates a seat structure in which the seatbelt retractor can be arranged on the vehicle seat in a space-saving manner.The vehicle seat can be designed more compactly in relation to the arrangement of the seatbelt retractor. For this purpose, one of the structural components is specifically provided with a cavity to accommodate the retractor. The shape and position of this cavity can be precisely adapted to the external shape of the retractor and its function, e.g., regarding the routing of the seatbelt. The load-bearing structural component can also replace the previously required frame of the retractor by mounting the retractor's spool directly on the load-bearing structural component or on a component rigidly connected to it. Furthermore, the tensile forces occurring during a restraint event can now be transferred directly into the structural component, with the shape of the cavity specifically designed to absorb these restraint forces.Since the structural component of the seat is already designed to absorb seating forces and other forces acting on the vehicle seat, it already possesses sufficient strength, which the proposed solution also utilizes to absorb the restraint forces exerted by the seat belt. Furthermore, due to the integrated cavity and the resulting three-dimensional design with its angled walls, the load-bearing structural component exhibits particularly high torsional and bending stiffness, which is advantageous for load bearing and occupant restraint in the event of an accident.

[0012] The load-bearing structural component can be designed such that its potential load-bearing capacity changes along its longitudinal axis in response to external or internal forces. These forces can act externally on the structural component, for example, via the seatbelt or the occupant in the seat, or internally, for example, via a torque generated by a seatbelt tensioner. Preferably, the potential load-bearing capacity decreases along the structural component from the seatbelt exit point. This can be achieved by having more walls in the area of ​​the seatbelt exit point or the adjacent area than in the area furthest from the seatbelt exit point.

[0013] The advantage of the proposed solution lies in the fact that, firstly, the structural component of the seat can be prefabricated very cost-effectively as a multi-formed part or obtained as a semi-finished product. Secondly, the U-shaped profile rail features a very large access opening due to the open side between the legs. Furthermore, the profile rail has three large contact and fastening surfaces formed by the inner sides of the legs and the base. Finally, the U-shaped profile rail exhibits high torsional and bending stiffness due to its shape, which is advantageous for absorbing the forces acting during restraint.

[0014] It is further proposed that the profile rail be closed by a cover plate. The cover plate closes the profile rail to form a profile closed in all four radial directions, thereby additionally stiffening the profile rail. Furthermore, the cover plate closes the cavity within the profile rail, so that the belt retractor and its additional components are protected from external mechanical impacts.

[0015] It is further proposed that the cavity have an opening through which a safety belt, which can be wound onto the belt retractor, is led out. The opening serves to lead out the safety belt and can also be used for installation, in which case an insert part can be provided to reduce the size of the opening after the belt retractor has been installed.

[0016] It is further proposed that the opening be formed by a cutout in the profile rail. The cutout is preferably located in the middle wall, i.e., the base surface, so that the seat belt is extended through the profile rail. The belt retractor is supported in the profile rail on a side opposite the extension direction of the seat belt, ensuring that the reaction forces during extension of the seat belt or restraint of the occupant are ideally absorbed by the profile rail and transferred to the seat structure. The cutout in the profile rail can be adapted to the seat belt in geometry as a narrow slot and can also be provided with appropriate radii or inserts to increase the edges, thus minimizing stress on the seat belt in any given installation.

[0017] It is further proposed that the legs of the profile rail have different heights extending from the base surface. This proposed improvement allows the opening width of the opening in the profile rail to be increased by widening the distance between the edges of the legs due to their different heights, compared to the distance between edges of identical heights.

[0018] It is further proposed that the shorter leg of the structural component, in its intended installation position, faces the seat surface of the vehicle seat. With this proposed improvement, the enlarged opening of the seat surface is thus oriented towards the side of the restrained occupant, the same side from which the seat belt exits. This allows the belt retractor to be positioned within the cavity in such a way that it is partially covered by one of the legs and thus protected, while the seat belt can exit tangentially from the retractor over the shorter leg.

[0019] It is further proposed that the belt retractor be mounted in a web supported between the legs of the profile rail. In addition to supporting the belt retractor, the web can also stiffen the profile rail by preventing the two legs from bending relative to each other under applied forces. The web itself is specifically shaped, dimensioned, and positioned within the profile rail to support its primary function of mounting the belt shaft. Furthermore, the web can also accommodate additional functional components, such as sensors, actuators, or locking devices. In this case, the webs can also be considered functional walls.

[0020] It is further proposed that at least a second web, supported between the legs of the profile rail and spaced apart from the first web, be provided. This second web improves the deformation stiffness of the legs relative to each other, as well as the torsional stiffness of the profile rail, and thus the dimensional stability of the structural component in the event of a restraint. Furthermore, the second web can also be used for additional support of the belt retractor and / or for supporting other assemblies interacting with the belt retractor.

[0021] It is further proposed that the belt retractor have a belt spool rotatably mounted about a pivot axis, and that the belt retractor be arranged such that the pivot axis of the belt spool is aligned parallel to the longitudinal direction of the profile rail. This allows for a particularly compact and space-saving arrangement of the belt retractor. If the webs are oriented perpendicular to the profile rail, the mounting can be implemented particularly simply, as the pivot axis of the belt spool of the belt retractor is also aligned perpendicular to the webs provided for mounting.

[0022] It is further proposed that the seat structure comprises two parallel longitudinal struts spaced apart from each other, which run longitudinally along a section of the seat structure forming a backrest, and that the load-bearing structural element, with its cavity and the belt retractor arranged therein, connects the two longitudinal struts at their ends to form a stable edge of the backrest. The structural element and the longitudinal struts thus form a three-sided, stable frame for the backrest, which serves to support the occupant's upper body and, according to the invention, is additionally used to absorb restraint forces in the event of an accident.

[0023] It is further proposed that the load-bearing structural component be arranged such that the cavity opens towards one side of the vehicle seat. This proposed orientation of the structural component allows the seat belt wound onto the retractor to be guided more easily from the vehicle seat towards the occupant seated there.

[0024] It is further proposed that the cover plate should cover the free end edges of the legs. The cover plate closes the profile rail to form a profile closed in all four radial directions, thereby additionally stiffening the profile rail. Furthermore, the cover plate closes the cavity within the profile rail, so that the belt retractor and its additional components are protected from external mechanical impacts.

[0025] It is further proposed that the cover plate be pivotably connected to at least one free edge of a leg via a hinge. The connection created by the hinge enables simplified, precise positioning of the cover plate by first pivoting the cover plate to one edge of a leg of the profile rail via the hinge and then pivoting it to the other edge of the opposite leg, with the cover plate being supported by the hinge against the edge of the opposite leg.

[0026] It is further proposed that the profile rail have a retaining plate on at least one of its end faces, which has at least one fastening element for attachment to a seat structure. The retaining plate serves both to stiffen the profile rail or the structural component and to attach it to the seat structure by providing a corresponding fastening element on the retaining plate, the shape and orientation of which are specifically designed for attachment to a corresponding fastening point on the seat structure.

[0027] The belt retractor can preferably be mounted on the mounting plate, so that the bearing forces and also the tensile forces acting in the event of restraint are introduced directly into the seat structure via the mounting part and the profile rail is relieved accordingly.

[0028] Furthermore, a spring cassette of the belt retractor can preferably be held on the outside of the mounting plate. A drive spring is held within the spring cassette, one end of which is supported by the housing of the spring cassette against the mounting part, and the other end of which is connected to a belt shaft of the belt retractor, so that the belt shaft is spring-tensioned in the winding direction. The mounting part is thus also used to support the drive spring. The spring cassette is also deliberately positioned on the outside of the mounting plate, so that no additional installation space needs to be provided for the spring cassette in the profile rail.

[0029] The structural component can preferably be made from a sheet of metal, so that firstly it can be produced cost-effectively in large series by means of a plastic bending and forming process and secondly it is made from a material that is sufficiently stable for the requirements of restraining the occupant.

[0030] Alternatively, the structural component can also be made from a fiber-reinforced plastic part. Modern fiber-reinforced plastics such as GRP or CFRP exhibit similarly high strength to metal or steel, but are significantly lighter. Furthermore, they can be easily manufactured in complex shapes using appropriate molds, eliminating the need for a correspondingly complex post-processing procedure.

[0031] It is further proposed that the structural component have at least one or more stiffening ribs in the cavity area. These stiffening ribs can very efficiently increase the deformation resistance of the structural component with only a slightly higher weight. The ribs can be produced as simple thickenings on the surface, for example by welding or printing, or they can divide the cavity of the structural component into different sections, forming walls that extend from one wall of the cavity to the opposite wall.

[0032] It is further proposed that the structural component has two stepped, offset abutments for attachment to the seat structure. These stepped abutments support the structural component on the seat structure in two offset planes, both vertically and horizontally.

[0033] One of the abutments can preferably be designed as a pivot bearing and the other as a mounting flange. The fastening process then takes place by first inserting the structural component into the abutment designed as a pivot bearing and then pivoting it towards the other abutment designed as a mounting flange, and finally fastening it to it.

[0034] It is further proposed that the structural component has a fastening projection at each end, allowing it to be attached to a longitudinal strut of a backrest in the seat structure. The structural component thus connects the two longitudinal struts and stiffens the seat structure into a frame.

[0035] The invention is explained below with reference to preferred embodiments and the accompanying figures. Fig. 1 shows two longitudinal struts of a vehicle seat with a load-bearing structural element according to the invention; Fig. 2 shows the load-bearing structural element with a cavity and a belt retractor arranged therein; Fig. 3 shows a sectional view of the load-bearing structural element with the cavity and the belt retractor arranged therein; and Fig. 4 shows the load-bearing structural element in a second embodiment.

[0036] In the Figure 1The seat structure is a part of a vehicle seat's backrest. It forms the rigid core of the seat and is additionally fitted with springs and / or padding to improve seating comfort. Furthermore, the seat structure incorporates other functional components such as seat adjustment mechanisms, a headrest, electronic devices like displays, and heating elements.

[0037] The seat structure comprises a composite of several load-bearing structural elements 2, two of which are formed by longitudinal struts 1 aligned parallel to each other. The upper ends of the longitudinal struts 1 are connected to each other by a load-bearing structural element 2 designed according to the invention to form a dimensionally stable upper surface of the backrest. To connect the longitudinal struts 1, raised tabs 4 with fastening openings are provided on them, and fastening openings are also provided on the structural element 2 through which the parts are connected to each other either by screws or rivets. Furthermore, a headrest support 3 in the form of two raised bars is provided on the structural element 2.

[0038] In the Figure 2The load-bearing structural part 2 is shown in an enlarged view, visible as a single component. The load-bearing structural part 2 comprises, as its basic component, a U-shaped profile rail 7 with a base surface 10 and two opposing, parallel, wall-like legs 8 and 9 extending upwards from the base surface 10. The profile rail 7 has an opening 28 formed between the edge faces of the legs 8 and 9, which is enclosed by a [missing element] in the Figure 1 The recognizable insert part 6 is closed, but that in the Figure 2For better visibility of structural part 2, the insert part 6 has been omitted. The insert part 6 is formed by a plate with a shape adapted to the form of the opening 28 and has a slot 13 through which a safety belt 12, described in more detail below, is guided from a cavity 21 between the legs 8 and 9 to the outside, towards a restrained occupant on the vehicle seat. The insert part 6 closes or reduces the opening 28 except for the designated slot 13, so that the cavity 21 is closed to the outside and a belt retractor 40 provided therein is protected from mechanical impact. The end faces of the profile rail 7 are each closed by a web 15 and 20.

[0039] The belt retractor 40 with a belt spool 14 and the safety belt 12 that can be wound onto it is arranged in the cavity 21 of the load-bearing structural part 2, which is located in the Figure 3As can be seen in the sectional view. The belt retractor 40 comprises, in addition to the belt spool 14, a force limiting device 25 with several torsion bars 26, a pyrotechnic irreversible belt tensioner 24, and a reversible electromechanical belt tensioner 23 in a coaxial arrangement to the axis of rotation of the belt spool 14. The external dimensions of the belt spool 14 with the maximum length of the safety belt 12 wound on it, as well as the external dimensions of the force limiting device 25, the pyrotechnic belt tensioner 24, and the electromechanical belt tensioner 23, are selected in the cross-sectional area perpendicular to the axis of rotation of the belt spool 14 such that they are not larger than the dimensions of the cavity 21 perpendicular to the longitudinal extent of the profile rail 7, so that they can be arranged in the cavity 21 of the profile rail 7.

[0040] The profile rail 7 has several webs 15, 16, 17, 18, 19, and 20 in the form of wall sections oriented perpendicular to the longitudinal extent of the profile rail 7. These webs extend from one leg 8 or 9 to the other leg 8 or 9 and are connected to them. Furthermore, the webs 15, 16, 17, 18, 19, and 20 can extend to the base surface 10 of the profile rail 7, thus filling the entire cross-sectional area of ​​the profile rail 7. The webs 15, 16, 17, 18, 19, and 20 each have one or more openings or projections in which the belt retractor or parts thereof, such as the belt spool 14, are mounted, fastened, and / or guided. Furthermore, for example, one of the webs 15, 16, 17, 18, 19 and 20 may also have a toothing or other type of blocking design in which the belt spool 14 or other parts of the belt winder can be blocked.Furthermore, the webs 15, 16, 17, 18, 19, and 20 can also have additional cavities for accommodating further components of the belt retractor, such as pyrotechnic propellant charges for the pyrotechnic belt tensioner 24, electronic components such as sensors, electronic control units, or storage units. If the webs 15, 16, 17, 18, 19, and 20 extend from one leg 8 or 9 to the other leg 8 or 9, they can also be used to stiffen the profile rail 7, which in turn is advantageous for load bearing and the dimensional stability of the profile rail 7 in the event of occupant restraint. The components of the belt retractor are deliberately arranged coaxially and one behind the other, so that the assembly deliberately has smaller radial dimensions and can therefore also be arranged in a narrow, elongated cavity 21 of the profile rail 7.This allows the profile rail 7 and the load-bearing structural part to be designed to be correspondingly narrow and elongated, which is particularly advantageous for the use of the load-bearing structural part according to the invention in a seat structure of the vehicle seat.

[0041] In the Figure 3 The load-bearing structural component according to the invention can be seen in the section through the profile rail 7 and the belt winder. The profile rail 7, which has a U-shaped cross-section, has legs 8 and 9 facing the viewer in this illustration and a base surface 10. The cavity 21, in which the belt winder is arranged, is provided between the legs 8 and 9. The cavity 21 is subdivided by six webs 15, 16, 17, 18, 19, and 20, with the two outer webs 15 and 20 closing the cavity 21 to the outside at both ends of the profile rail 7.

[0042] A spring cassette with a drive spring 27 is held on the right-hand web 15. This spring is connected to the belt spool 14 and thereby pre-tensions the belt spool 14 in the winding direction of the safety belt 12 wound onto it. The belt spool 14 is provided at its end projecting into the profile rail 7 with a force-limiting device 25. This device consists of a tubular extension 38 arranged coaxially with the belt spool 14, three torsion bars 26, 36, and 37 arranged in series, and a locking element 41 that can be locked against rotation relative to the profile rail 7. In the present embodiment, three torsion bars 26, 36, and 37 are provided, each of which is connected at one end to the belt spool 14 or 37, respectively.The torsion bars 26, 36, and 37 are connected to the tubular extension 38 either directly or indirectly in a rotationally fixed manner and can be locked or detached from the profile rail 7 at their respective other ends by a switching device provided in one of the webs 16 or 17. This allows the torsion bars 26, 36, and 37 to be activated individually or in combination, enabling the restraint forces to be applied at different force limitation levels or in a stepped force limitation profile. The locking element 41 can be locked in the extension direction of the safety belt 12 by a vehicle-sensitive and / or belt-sensitive locking device, thereby blocking the force limiting device 25. This causes the force limiting device 25 to be automatically activated if the force limiting level defined by the force limiting device 25 is exceeded.Furthermore, a pyrotechnic, irreversible belt tensioner 24 is provided with a drive wheel 35 arranged coaxially to the belt reel 14. Upon activation, the drive wheel 35 drives the belt reel 14 in the winding direction via an intermediate clutch and tightens the seat belt 12. Additionally, a reversible belt tensioner 23 with an electric motor 22 is provided. Upon activation, the electric motor 22 drives the belt reel 14 in the winding direction via a second clutch or the same clutch as the pyrotechnic belt tensioner 24, thereby tightening the seat belt 12. The electric motor 22 is also arranged coaxially to the belt reel 14 and thus also to the force limiting device 25 and the pyrotechnic belt tensioner 24. Furthermore, an electronic control unit 29 is provided in the profile rail 7 of the load-bearing structural part 2. This control unit can be used to control the belt retractor 40 and / or other components.The load-bearing structural part 2 is a basic component of the seat structure, in that it connects to other parts of the seat structure, such as those in the . Figure 1 The longitudinal struts 1, which can be identified, are connected to each other. The structural part 2 thus has the task of forming the seat structure and, through the provided cavity 21, also serves to accommodate the belt retractor 40. The load-bearing structural part 2 can be pre-assembled as a module with the belt retractor 40 and then final-assembled as a single unit during the manufacturing of the seat structure or the vehicle seat.

[0043] The profile rail 7 forms the basic component of the load-bearing structural part 2 and is shaped and dimensioned according to the connection to be achieved with the other structural parts in the seat structure. The profile rail 7 can replace the previously required frame of the seat belt retractor 40 by serving both to support the seat belt retractor 40 and to attach the seat belt retractor 40 to the vehicle seat.

[0044] The belt retractor 40 is modularly designed with the belt spool 14 and the other assemblies, namely the force limiting device 25, the pyrotechnic belt tensioner 24 and the reversible belt tensioner 23, in a coaxial series arrangement. The assemblies are deliberately designed so that their radial outer dimensions do not exceed the dimensions of the belt winding on the belt spool 14 when the safety belt 12 is wound to its maximum extent, as shown in the Figure 3This can be seen. The maximum outer diameter of the belt retractor 40 is thus determined by the diameter of the belt reel when the safety belt 12 is wound up to its maximum. Since the belt reel has a circular cross-section, and the cavity 21 in the profile rail 7 or the housing in the Figure 4 If the cross-section is rectangular, the maximum dimensions specified by the belt winding shall also include a cavity with a cross-section that is rectangular and has side lengths corresponding to the diameter of the belt winding or slightly larger.

[0045] In addition to their bearing function, the webs 15, 16, 17, 18, 19, and 20 can also be considered functional walls by providing appropriate receptacles and arranging various functional units in or on the receptacles. To fulfill their bearing function, the webs 15, 16, 17, 18, 19, and 20 are preferably supported between the legs 8 and 9 and the base surface 10 of the profile rail 7 or between the Figure 4 The recognizable housing parts 30 and 31 are rotationally fixed.

[0046] The one in Figure 4 The recognizable alternative embodiment thus differs from the embodiment of the Figure 3by the fact that the belt winder 40 is provided here with a two-part housing with two housing parts 30 and 31 instead of a profile rail 7. The housing parts 30 and 31 are each U-shaped and enclose the belt spool 14 and the other assemblies, including the webs 15, 16, 17, 18, 19 and 20 in the assembled position facing outwards, as shown in the upper right illustration of the Figure 4As can be seen, the housing parts 30 and 31, in their assembled position, form an elongated cavity 21 with a square cross-section. Since the belt spool 14 with the safety belt 12 wound on it and the other assemblies have a circular cross-section, an elongated, approximately triangular, cross-sectional free space is provided at each corner between the belt winding of the belt spool 14, the assemblies, and the housing. This free space is used here for the arrangement of the tensioner drive tube 32. The tensioner drive tube 32 serves to guide a drive device, such as a chain of loosely connected masses or an elastic drive train, which is accelerated upon activation of the pyrotechnic belt tensioner and thereby brought into drive connection with the drive wheel 35.The drive wheel 35 and the belt spool are thereby subsequently driven to a rotary motion in the winding direction of the seat belt 12. The tensioner drive tube 32 has a linear section 33 and a curved section 34 and is aligned and arranged such that the linear section 33 is parallel to the axis of rotation of the belt spool 14 and the drive wheel 35, and the curved section 34 is tangential to the outer circumference of the drive wheel 35. The curved section 34 is curved exclusively in one plane, so that the curved section 34 and the linear section 33 are arranged in a plane which, in the assembled arrangement of the tensioner drive tube 32, runs parallel to the axis of rotation of the belt spool 14.

[0047] In their assembled position, housing parts 30 and 31, together with the belt winder 40 arranged therein, form a dimensionally stable housing, which is described as the one described in the Figure 1The load-bearing structural component that can be identified in the seat structure can be used.

[0048] The load-bearing structural part 2 with the profile rail 7 or the housing parts 30 and 31 was constructed according to the illustration in the Figure 1The horizontal installation geometry is described, which offers advantages regarding the horizontal orientation of the seat belt 12 as it is fed to the occupant. A horizontal orientation of the seat belt 12 as it is fed to the occupant is advantageous because it allows the seat belt 12 to be guided horizontally onto the occupant's shoulder without being redirected. Alternatively, the load-bearing structural part 2 can also be arranged vertically or at an angle on the seat structure. The seat belt 12 is then fed at an angle or redirected into the intended feeding direction onto the occupant by means of a separate deflection device.Furthermore, the structural part 2 can also be arranged at a lower point or on a side of the seat structure of the backrest instead of at an upper edge of the backrest, provided that the seat structure or the routing of the safety belt 12 requires and / or allows this. Instead of the profile rail 7 or the housing parts 30 and 31, it would also be conceivable to provide a tubular structural part 2 with a circular or other cross-section in which the belt retractor 40 is arranged and, in particular, inserted from the end face.

[0049] In the Figure 5 An alternative embodiment of the load-bearing structural part 2 can be seen, which is connected to two longitudinal struts 1 of the backrest and thereby stiffens or completes the seat structure of the backrest. The [details of the] Figure 6A fitting 50 is arranged on each of the visible end faces of the longitudinal struts 1, each fitting having a pair of claws 48 and a mounting surface 49. On the part located in the Figure 7The structural part 2, as shown in the illustration, has two stepped abutments 43 and 44. The upper abutment 43, shown at the front, is formed by two recesses in the profile rail 7, dimensioned to allow the claws 48 of the fitting 50 to engage in them. The lower abutment 44, shown at the rear, is formed by a downwardly projecting mounting flange of the profile rail 7, shaped and positioned so that, in the fixed position of the structural part 2, it rests flush against the mounting surfaces 49 of the fitting 50. To attach the structural part 2, it is positioned against the longitudinal struts 1 such that the claws 48 engage the upper abutments 43 at the front, thus pre-positioning the structural part 2.The front upper abutment 43 and the engaging claws 48 then form a pivot bearing, around which the structural part is subsequently pivoted until the rear lower abutment 44 rests against the mounting surface 49. The final fastening of the structural part 2 is then effected by two [unclear - possibly referring to a specific feature or component]. Figure 8 The screws are clearly visible. The rear lower abutment 44 has an opening in each of its outer sections into which the screws are inserted and then screwed into corresponding threads in the longitudinal struts 1. The abutment 44, in the form of the mounting flange, thus forms two mounting projections 45 via which the structural part 2 is connected to the longitudinal struts 1. The structural part 2 is then fastened in two abutments 43 and 44 arranged in a stepped pattern.

[0050] In the Figures 9 to 15Another alternative embodiment of the structural part 2 can be seen. The structural part 2 has an opening 28 formed in the profile rail 7 in the form of a cutout, through which the [unclear text] in the Figure 1The safety belt 12 shown extends outwards from the belt reel 14. The belt retractor 40 is thus supported on the inside of the profile rail 7 when tensile forces are exerted via the safety belt 12. Furthermore, the structural part 2 has two fastening points 6 in the form of two fastening projections 45, which are shaped to encompass the, in this case, slender rectangular-profile end faces of the longitudinal struts 1. The profile rail 7 also has a curved chamfer 53 on its lower edge, which faces the occupant and thus the backrest's contact surface, flattening the edge of the profile rail 7. This allows the upholstery or seat structure to be designed with a flatter profile without compromising the occupant's seating comfort.

[0051] As in the Figure 12As can be seen, the profile rail 7 is closed on the outer sides by a retaining plate 46, on which fastening elements 6 are provided in the form of downwardly projecting and laterally angled fastening projections 45. Furthermore, the retaining plates 46 serve to support the belt retractor 40 and, in particular, the belt spool 14. In addition, the mounting plates 46 shown in the illustration serve to support the belt retractor 40 and, in particular, the belt spool 14. Figure 12 right retaining plate 46 for fastening a spring cassette 42 arranged on the outside, in which a drive spring (not shown) is arranged that pretensions the belt spool 14 in the winding direction.

[0052] The retaining plate 46, arranged on the side of the belt spool 14, together with an L-shaped retaining element 54, forms a frame with a U-shaped cross-section in which the belt spool 14 is mounted, as shown in the Figure 13 can be seen.

[0053] Furthermore, structural part 2, next to profile rail 7, has a [missing information] in the Figure 14and 15 The cover part 5, which can be identified, projects beyond the end faces of the legs of the profile rail 7 and thereby covers or completes the profile rail 7 to form a closed profile. The cover part 5 has a plurality of regularly arranged teeth 52 on one of its edge faces, which, together with a plurality of regularly arranged windows 51 in one of the edge faces of a leg of the profile rail 7, form a hinge 47. To mount the cover part 5, it is inserted with the teeth 52 into the windows 51 and then pivoted towards the profile rail 7 until it completely closes the profile rail in the mounting position.

Claims

1. Seat structure of a vehicle seat comprising a backrest having two longitudinal struts (1) aligned in parallel with one another, and a load-bearing structural part (2) connecting the upper ends of the longitudinal struts (1) to one another to form a dimensionally stable upper side of the backrest, wherein - the structural part (2) has a cavity (21) in which a belt retractor (40) is arranged, wherein - the load-bearing structural part (2) comprises a profile rail (7) which is open on one side and has two opposite side faces (8, 9) extending from a base face (10), and - the cavity (21) is formed by the intermediate space between the opposite side faces (8, 9), characterized in that - the profile rail (7) is completed by a cover part (5) to form a closed profile.

2. Seat structure according to claim 1, characterized in that - the cavity (21) has an opening (28) through which a safety belt (12) which can be wound on the belt retractor (40) is guided out.

3. Seat structure according to claim 2, characterized in that - the opening (28) is formed by a cutout in the profile rail (7).

4. Seat structure according to any of the preceding claims, characterized in that - the side faces (8, 9) of the profile rail (7) have a different height starting from the base face (10).

5. Seat structure according to claim 4, characterized in that - the side face (8, 9) having the smaller height faces a seat surface of the vehicle seat in the intended installation position of the structural part (2).

6. Seat structure according to any of the preceding claims, characterized in that - the belt retractor (40) is mounted in a web (15, 16, 17, 18, 19, 20) which is supported between the side faces (8, 9) of the profile rail (7).

7. Seat structure according to claim 6, characterized in that - at least a second web (15, 16, 17, 18, 19, 20), which is supported between the side faces (8, 9) of the profile rail (7) and is spaced apart from the first web (15, 16, 17, 18, 19, 20), is provided.

8. Seat structure according to any of claims 3 to 7, characterized in that - the belt retractor (40) has a belt reel (14) mounted rotatably about an axis of rotation (A), and - the belt retractor (40) is arranged such that the axis of rotation (A) of the belt reel (14) is aligned in parallel with the longitudinal direction of the profile rail (7).

9. Seat structure according to any of claims 3 to 8, characterized in that - the cover part (5) covers the free edges on the ends of the side faces (8, 9).

10. Seat structure according to any of the preceding claims, characterized in that - the cover part (5) is pivotably connected to at least one free edge of a side face (8, 9) by means of a hinge (47).

11. Seat structure according to any of the preceding claims, characterized in that - the profile rail (7) has, on at least one of the end faces thereof, a holding plate (46) which has at least one fastening attachment (6) for fastening to a seat structure.

12. Seat structure according to claim 11, characterized in that - the belt retractor (40) is mounted on the holding plate (46).

13. Seat structure according to either claim 11 or claim 12, characterized in that - a spring cassette (42) of the belt retractor is held on the outside of the holding plate (46).

14. Seat structure according to any of the preceding claims, characterized in that - the structural part (2) is formed from a metal sheet.

15. Seat structure according to any of the preceding claims, characterized in that - the structural part (2) is formed from a fiber-reinforced plastics part.

16. Seat structure according to any of the preceding claims, characterized in that - the structural part (2) has one or more stiffening ribs at least in the region of the cavity (21).

17. Seat structure according to any of the preceding claims, characterized in that - the structural part (2) has two abutments (43, 44) arranged offset from one another in a stepped manner for fastening to the seat structure.

18. Seat structure according to claim 17, characterized in that - one of the abutments (43, 44) is designed as a pivot bearing and the other abutment (43, 44) as a fastening flange.

19. Seat structure according to any of the preceding claims, characterized in that - the structural part (2) has, at each of the ends thereof, a fastening projection (45), by means of which the structural part (2) can be fastened to a relevant longitudinal strut (1) of a backrest of the seat structure.

20. Seat structure according to any of the preceding claims, characterized in that the load-bearing capacity of the structural part (2) decreases along the longitudinal orientation thereof.