Device for adjusting the hardness and / or geometry of seat elements of a vehicle seat, frame for a vehicle seat, and vehicle seat with such a device

Abstract

Device for adjusting the hardness and / or geometry of seat elements of a vehicle seat with an adjustment device (1; 70-74) for adjusting the hardness and / or geometry of a seat element of the vehicle seat, and an actuating device (9) for actuating the adjusting device (1; 70-74), characterized in that the adjusting device (1; 70-74) comprises an auxetic material (50) and is designed such that, when actuated by the actuating device (9), a tensile force is exerted on the auxetic material (50) in a first direction (x1), causing the auxetic material (50) to stretch in the first direction (x1) and to expand in a second direction (x2) transversely to the first direction (x1) in order to adjust the hardness and / or geometry of the seat element of the vehicle seat, wherein the height of the auxetic material (50) in the second direction (x2) is at least sectionally different, such that a surface of the auxetic material (50) has at least sectionally a curved or chamfered contour.

Description

Field of the invention

[0001] The present invention relates generally to the adjustment of the hardness and / or geometry of seat elements of a vehicle seat, preferably a motor vehicle seat, and particularly relates to a device for adjusting the hardness and / or geometry of seat elements of a vehicle seat, a frame for a vehicle seat and a vehicle seat with at least one such device. State of the art

[0002] DE 20 2009 000 559 U1 of the applicant discloses a device for adjusting the hardness and geometry of seat elements of a motor vehicle seat according to the preamble of patent claim 1. Such devices are adjusted electrically with a spindle drive or mechanically with a Bowden cable, but have a comparatively complicated structure with a relatively large number of mechanical components.

[0003] Comparable devices are known from DE 197 37 271 C1, DE 90 14 111 U1, DE 20 2005 006 988 U1, DE 197 50 116 C2, DE 11 2009 000 495 T5 and DE 10 2016 013 923 A1.

[0004] There is therefore a need for such devices with a simplified structure.

[0005] Auxetic materials are known from the state of the art that have the unusual property of expanding transversely to the stretching direction when stretched. These materials are characterized by a negative Poisson's ratio.

[0006] The use of auxetic materials for vibration or damping absorbing structures is known from the prior art, as disclosed, for example, in EP 1 612 108 A1 or US 2013 / 0 264 757 A1.

[0007] US 2015 / 0 320 220 A1 discloses an office chair with a horizontal seat portion and an upright backrest comprising a flexible membrane or grid. At least a portion of the grid comprises an auxetic material with a negative Poisson's ratio, wherein stretching of the auxetic material in a first and / or second direction causes the membrane or grid to expand in the other of the second and / or first directions. Summary of the invention

[0008] The object of the present invention is to further simplify and make more reliable the adjustment of the hardness and / or geometry of seat elements of a vehicle seat.

[0009] This object is achieved by a device for adjusting the hardness and / or geometry of seat elements of a vehicle seat according to claim 1, by a frame for a vehicle seat with at least one such device according to claim 25, by a vehicle seat according to claim 28, and by a use according to claim 37. Further advantageous embodiments are the subject of the dependent subclaims.

[0010] According to the present invention, a device for adjusting the hardness and / or geometry of seat elements of a vehicle seat, in particular a motor vehicle seat, is provided, comprising an adjusting device for adjusting the hardness and / or geometry of a seat element of the vehicle seat, and an actuating device for actuating the adjusting device. According to the invention, the adjusting device comprises an auxetic material, wherein the adjusting device is designed such that, upon actuation by the actuating device, a tensile force is exerted on the auxetic material in a first direction, thereby causing an elongation of the auxetic material in the first direction and an expansion of the auxetic material in a second direction transverse to the first direction in order to adjust the hardness and / or geometry of the seat element of the vehicle seat.

[0011] Extensive experiments conducted by the inventor with auxetic materials have shown that, due to their unusual property of expanding transversely to the direction of stretching when stretched, auxetic materials are also ideally suited for adjusting the hardness and / or geometry of sections of a vehicle seat, particularly in motor vehicle seats. Compared to mechanically, electrically, or pneumatically driven seat adjustments, adjustment devices according to the present invention using auxetic materials are characterized by fewer components, higher efficiency, smaller space requirements, greater variability, lower weight, and a simpler design. Adjustment devices using auxetic materials can, in particular, be easily designed with curved contours or with variable surfaces.

[0012] The actuating device can be a purely mechanical actuating device, for example a rotary wheel or a Bowden cable, an electrical actuating device, for example an electric motor with a spindle drive, or even a pneumatic drive, and enables controlled adjustment in the first direction. This adjustment is translated by the adjusting device into a stretching of the auxetic material in the first direction. For this purpose, the auxetic material is coupled to the adjusting device in a suitable manner, as explained below. Preference is given to arrangements in which the auxetic material is attached or mounted at one end to a stationary reference surface, while the opposite end, viewed in the first direction, is coupled to the adjusting device, so that the auxetic material can be suitably stretched in the first direction when actuated by the actuating device.The expansion of the auxetic material in the second direction, perpendicular to the first direction, should not be impeded by housing covers or the like of the adjustment device. The adjustment device is therefore preferably open on at least one side in the second direction to allow free expansion of the auxetic material. Preferably, the adjustment device is open on two opposite sides in the second direction to allow symmetrical expansion of the auxetic material in the second direction. In the first direction, the auxetic material is preferably completely accommodated in the adjustment device.

[0013] To be able to trigger an adjustment in a seat section in a controlled manner, it is preferred if the auxetic material, as it expands transversely to the direction of extension, presses against an adjustment surface, which in turn causes an adjustment of the seat section, for example, a padded section of the vehicle seat. This adjustment surface can be solid and plate-shaped, such as adjustable function flaps.

[0014] According to a further embodiment, the adjustment surface is pivotally mounted relative to a stationary base surface, with the auxetic material being arranged between the stationary base surface and the pivotally mounted adjustment surface, so that the adjustment surface is pivoted relative to the stationary base surface when the auxetic material expands in the second direction. The expansion of the auxetic material is thus translated into a defined angular adjustment, which is suitable, for example, for adjusting the side bolsters, the front edge, or lumbar supports of a vehicle seat.

[0015] According to a further embodiment, the adjustment surface comprises two sections on two sides of the auxetic material, which are opposite each other in the second direction, wherein a distance between the two sections is increased upon expansion of the auxetic material in the second direction. The expansion of the auxetic material is thus translated into a defined expansion of a seat section.

[0016] According to a further embodiment, the adjustment surface is designed to be circumferential or substantially circumferential in a sectional view perpendicular to the first direction and consists at least in sections of an expandable material, so that when the auxetic material expands in the second direction, a volume enclosed by the adjustment surface is increased, for example in the manner of a bubble of a conventional pneumatic adjustment device.

[0017] According to a further embodiment, the adjustment surface is designed as a hose or tube made of an expandable material whose longitudinal axis extends parallel to the first direction. This geometry is particularly suitable for fixing and coupling the auxetic material to the adjustment device. For example, one end of the auxetic material can be connected to an end face of the hose or to an external reference surface, such as a retaining clip fixedly attached to the vehicle seat, while the opposite end of the auxetic material can be coupled directly or indirectly to the adjustment device. If the hose is open at least at one end, the adjustment required to stretch the auxetic material in the first direction can take place without significant geometric restrictions.

[0018] According to a further embodiment, the auxetic material has a plurality of coupling sections for coupling to the actuating device, wherein the actuating device applies the tensile force in the first direction jointly to all coupling sections to cause the elongation of the auxetic material in the first direction and the expansion of the auxetic material in the second direction transverse to the first direction. In this way, the auxetic material can be suitably adjusted homogeneously across all coupling sections.

[0019] According to a further embodiment, the plurality of coupling sections comprises first coupling sections that are fixedly mounted on a first side of the auxetic material, and second coupling sections that are adjustably mounted on a second side of the auxetic material, which is opposite the first side in the pulling direction, and are coupled to the actuating device. The fixedly mounted holding surface is expediently fixedly connected to a frame of the vehicle seat, while the second coupling sections can be adjusted in a controlled manner relative to this fixed holding surface.

[0020] According to a further embodiment, the first coupling sections are jointly fastened to a retaining clip, and the second coupling sections are jointly fastened to a tension element which is mounted such that the tension element is adjusted in the first direction relative to the retaining clip when actuated by the actuating device, wherein the retaining clip is designed to be open at least on one side in the second direction. The retaining clip can be easily connected to a frame or chassis of the vehicle seat and adapted to the respective geometry in the seat section to be adjusted. In addition to retaining clips with straight legs, a base and / or lateral legs of the retaining clip can thus be provided with a suitable profile in order to impart a suitable profile to the adjustment device.For example, a suitable shape at a front and / or rear end of the adjustment device, viewed in the first direction, is conceivable here.

[0021] According to a further embodiment, the retaining clip is designed as a U-shaped section of a retaining frame that encloses the tension element and the auxetic material together in a plane in which the first tension direction lies. Such a retaining clip can advantageously be installed in a modular manner and, depending on the requirements, can be coupled optionally with a suitable actuation device, in particular with a mechanical drive or an electric drive. The decision regarding this can also be made flexibly during the final assembly of a vehicle seat.

[0022] According to a further embodiment, the tension element has guide lugs or guide grooves on two sides that are opposite one another in a direction perpendicular to the first and second directions. These guide lugs or guide grooves engage in correspondingly designed guide grooves or guide lugs of the retaining clip, so that the tension element is precisely and reliably guided in the first direction. This enables precise, uniform adjustment of the auxetic material across its entire width, particularly in the case of a block made of an auxetic material that is composed of multiple subunits and / or has a relatively large width in a direction perpendicular to the first and second directions.

[0023] According to a further embodiment, a plurality of retaining clips and associated tension elements are provided for the simultaneous adjustment of a plurality of adjustment devices. The actuating device is coupled to a central tension element, and the central tension element is coupled to the plurality of associated tension elements, so that upon actuation of the actuating device, all associated tension elements are adjusted synchronously. The central tension element is preferably designed with mirror symmetry to enable uniform adjustment of the auxetic material across its entire width.

[0024] According to a further embodiment, the central tension element has guide lugs or guide grooves on two opposite sides, which engage in correspondingly designed guide grooves or guide lugs of a central holding clamp, so that the central tension element is guided in the central holding clamp, wherein the central tension element is coupled to all associated tension elements via coupling means, for example coupling tension cables or coupling rods.

[0025] According to a further embodiment, the actuating device is designed as a spindle drive having a spindle drivable by a drive device, which engages with a spindle nut that is coupled to the tension element or to the central tension element, or preferably forms the latter. The spindle drive can be driven optionally by a mechanical or electrical rotary drive, in particular by a compact electric motor commonly used for adjusting seat sections.

[0026] According to a further alternative embodiment, the actuating device adjusts a pull cable of a Bowden cable, wherein the pull cable is coupled to the pull element or to the central pull element, in particular being directly attached thereto. The Bowden cable can be adjusted in particular with a mechanical actuating element, for example, a rotary knob or the like on the vehicle seat.

[0027] According to a further embodiment, the tension element or the central tension element is pretensioned into an initial position by means of a return element, in particular by means of a compression spring, so that the auxetic material can reliably, in particular automatically, return to its original state with comparatively little expansion of the auxetic material in the second direction when the tensile force in the first direction is no longer applied or decreases.

[0028] According to a further embodiment, the adjusting device stretches the auxetic material in the first direction between a predetermined first position and a second predetermined position, wherein an outer dimension of the auxetic material in the second direction is larger in the second predetermined position than in the first predetermined position.

[0029] According to a further embodiment, the auxetic material is prestressed in the first direction into the first position by means of a restoring element, in particular by means of a compression spring.

[0030] According to a further embodiment, the auxetic material is formed from a plurality of cells of the same basic shape, which are connected to one another to form a material block or are formed in one piece, wherein the cells are assigned a first dead center with a first width of the cells in the second direction and a second dead center with a second width of the cells in the second direction, which is greater than the first width, wherein a dependence of the width of the cells in the second direction on the extension of the cells in the first direction follows a predetermined function, and the actuating device is designed such that with a linear adjustment of the adjusting device, the adjustment of the width of the cells in the second direction essentially follows a linear function.Typically, the dependence of the width of the cells in the second direction, and thus the external dimensions of the auxetic material in the second direction, follows a non-linear function. Due to the toggle action of the longitudinal webs in the case of a diamond-folded structure, this dependence can, for example, essentially follow a sine or cosine function, with a comparatively slight gradient in the area of ​​the two reversal points or dead centers. The actuating device can account for this non-linear characteristic and be operated in such a way that the user always feels an adjustment of the geometry and / or hardness of the seat section proportional to the adjustment value triggered by it.

[0031] According to a further embodiment, the actuating device is a mechanical actuating device to which a control cam with a non-linear control curve for controlling the tensile force in the first direction is assigned, in particular an eccentric control cam or a control cam with an eccentric control surface. The control cam can be easily adapted to the aforementioned non-linear dependency in order to enable proportional adjustment of the auxetic material. A control cam designed in this way is fundamentally suitable for both purely mechanical and electrical drives. Such a control cam is particularly suitable for mechanical actuating devices, for example for actuating devices with a Bowden cable or a mechanical rotary wheel on the vehicle seat for adjustment.

[0032] According to a further alternative embodiment, the actuating device is an electrically or pneumatically operated actuating device, to which an electronic control unit with a memory is assigned. A characteristic curve of the predetermined function is stored in the memory, and the electronic control unit controls the actuating device such that, upon linear adjustment of the adjusting device, the adjustment of the width of the cells in the second direction essentially follows a linear function. The electronic control unit allows virtually any characteristic curve of the adjusting device to be mapped to linear dependencies of the adjustment of the auxetic material.

[0033] According to a further embodiment, in the first position of the auxetic material, the first width of the cells in the second direction is greater than a minimum width of the cells in the second direction. Furthermore, in the second position of the auxetic material, the second width of the cells in the second direction can be smaller than a maximum width of the cells in the second direction. By limiting the adjustment to areas that are sufficiently far away from the aforementioned reversal or dead centers of the auxetic material, a linear dependency of the aforementioned adjustment can be realized in an advantageously simple manner. Due to this limitation of the adjustment range, the risk of excessive compression or overstretching and thus damage to the auxetic material near the first or second dead center or reversal point can be reliably excluded.

[0034] According to the invention, the height of the auxetic material varies at least in sections in the second direction, so that a surface of the auxetic material has a curved or beveled contour at least in sections. In this way, the auxetic material with any desired outer contour is adapted to the respective requirements of the vehicle seat. This adaptation can, in particular, correspond to a state of the auxetic material with minimal or maximum expansion in the second direction.

[0035] According to a further embodiment, the height of the auxetic material is lower at a front and / or rear end, viewed in the first direction, than at a central portion of the auxetic material. This allows a suitable shape of the seat portion to be easily realized even at the front and / or rear end, without the need for additional elements that define the outer contour. This can be used to form rounded edges or borders of the vehicle seat or its upholstery, for example, in the region of a front edge of a seat pan of a vehicle seat.

[0036] According to a further embodiment, the auxetic material is manufactured as a diamond-folded structure made of a plastic material, in particular by means of an injection molding or lamination process. The toggle levers typical of a diamond-folded structure ensure permanently reliable adjustability of the width of the auxetic material in the second direction.

[0037] A further aspect of the present invention relates to a frame for a vehicle seat, comprising a seat pan and a backrest, wherein at least one device for adjusting the hardness and / or geometry of a seat element of the vehicle seat is attached to the frame. According to the invention, the at least one device for adjusting the hardness and / or geometry of the seat element of the vehicle seat is designed as a device for adjusting the hardness and / or geometry of the seat element of a vehicle seat, as described above.

[0038] According to a further embodiment, the device for adjusting the hardness and / or geometry of a section of the vehicle seat is designed as a device for adjusting the curvature and / or width of side bolsters of a seat base or the backrest, as a device for adjusting an upper backrest part of a split backrest, as a device for adjusting a lumbar support, as a device for adjusting a thigh support of the seat base or as a device for adjusting the hardness and / or geometry of a headrest module connected or connectable to the frame.

[0039] According to a further embodiment, the device for adjusting the hardness and / or geometry of a section of the vehicle seat is connected via at least one support element to an associated section of the seat pan or the backrest or to a headrest module connected or connectable to the frame, whereby a defined, stationary support of the adjusting device on the frame can be ensured in a simple manner.

[0040] A further aspect of the present invention relates to a vehicle seat, in particular a motor vehicle seat, having a frame which has a seat pan and a backrest, wherein at least one device for adjusting the hardness and / or geometry of a seat element of the vehicle seat is fastened to the frame, and wherein the seat pan and the backrest are provided with a main foam element in order to form a seat bottom part and a back part of the vehicle seat. According to the invention, the at least one device for adjusting the hardness and / or geometry of the seat element of the vehicle seat is designed as a device for adjusting the hardness and / or geometry of the seat element of a vehicle seat, as explained above, wherein it is received in a recess in the main foam element.When the auxetic material is adjusted, a corresponding deformation of the main foam element occurs, which is, however, perceived as more comfortable by users due to the additional deformability of the main foam element.

[0041] According to a further embodiment, the at least one device for adjusting the hardness and / or geometry of the section of the vehicle seat is accommodated in a primary foam housing, which is accommodated in the recess in the main foam element. This allows for a cost-effective, modular design.

[0042] According to a further embodiment, the primary foam housing comprises a profiled front end piece and / or a profiled rear end piece, with which a suitable profiling can be easily realized, especially on edges or corners of a vehicle seat.

[0043] According to a further embodiment, the auxetic material in the primary foam enclosure is covered with an upper cover plate and / or lower cover plate in order to compensate for relative movements and different pressure points of the auxetic material.

[0044] According to a further embodiment, the auxetic material with the adjustment device is accommodated, preferably immovably, in a central receptacle of the primary foam housing. The upper cover plate and the lower cover plate are movably guided in an upper receptacle and a lower receptacle, respectively, above and below the central receptacle in the second direction, and a width of the central receptacle in a direction perpendicular to the first and second directions is greater than a width of the upper and lower receptacles, respectively. The adjustment device can thus be reliably accommodated in a fixed location in the central receptacle.

[0045] According to a further embodiment, the upper or lower cover plate is connected at its front and / or rear end, viewed in the first direction, to a retaining clip of the adjusting device via an elastic cover section.

[0046] According to a further embodiment, positioning holes are provided at the front and / or rear end of the retaining clip of the adjustment device, as viewed in the first direction. Furthermore, guide holes for guiding the upper or lower cover plate in the second direction can be provided at the front and / or rear end of the upper or lower cover plate, as viewed in the first direction. The positioning holes are preferably aligned with the guide holes in the second direction.

[0047] According to a further embodiment, the primary foam enclosure has a circular profile when viewed in a sectional view perpendicular to the first and second directions.

[0048] Alternatively, an upper side and / or lower side of the primary foam enclosure, viewed in the second direction, may be flattened.

[0049] A further aspect of the present invention relates to the use of an auxetic material for a device for adjusting the hardness and / or geometry of seat elements of a vehicle seat, in particular a motor vehicle seat, as disclosed in the present application. Figure overview

[0050] The invention will be described below by way of example and with reference to the accompanying drawings, from which further features, advantages, and objects to be achieved will emerge. They show: Fig. 1 shows the basic principle of an auxetic material for use as a medium for adjusting the hardness or inner contour of a vehicle seat according to the present invention; Fig. 2a shows the combination of several basic units made of an auxetic material to form a larger unit for use as a medium for adjusting the hardness or inner contour of a vehicle seat according to the present invention; Fig. 2b shows a perspective view of a base unit made of an auxetic material for producing an adjustment unit according to the present invention in an initial state and an adjusted state with a greater installation height; Fig. 2c shows, in a side view, three examples of basic units made of an auxetic material for producing an adjustment unit with different outer contours in the adjusted or non-adjusted state in the second direction; Fig. 3a shows a schematic side view of the structure of an adjustment unit according to the present invention, which operates according to the principle of a functional flap; Fig. 3b shows a schematic side view of the structure of a further adjustment unit according to the present invention, which operates according to the principle of a bubble with an adjustable outer profile; Fig. 4a shows the basic structure of an adjustment unit according to a first embodiment of the present invention in a schematic sectional view in an initial state; Fig. 4b shows the basic structure of an adjustment unit according to the first embodiment of the present invention in a schematic sectional view in an adjusted state; Fig. 5a shows a perspective view of the structure of an adjustment unit with a motor-driven spindle drive according to a second embodiment of the present invention; Fig. 5b and Fig. 5c shows a schematic sectional view of the adjustment unit after Fig. 5a in an initial state and an adjusted state; Fig. 6a and Fig. 6b shows two embodiments of a motor-driven spindle drive and a manually operable adjustment mechanism for coupling with an adjustment unit according to the present invention; Fig. 7a shows a schematic perspective view of the coupling of a manually operable adjustment mechanism with two adjustment units according to the present invention; Fig. 7b shows a schematic perspective view of the coupling of a motor-driven spindle drive with two adjustment units according to the present invention; Fig. 8a and Fig. 8b shows a schematic sectional view of the arrangement of an adjustment unit according to the present invention in a primary foam housing of a vehicle seat; Fig. 9 shows a perspective exploded view of the structure of a primary foam enclosure with an adjustment unit and motor-driven spindle drive; Fig. 10a and Fig. 10b Structure and mode of operation of a flap adjuster according to the present invention; Fig. 11a and Fig. 11b Examples of preferred positions of an adjustment unit according to the present invention in a motor vehicle seat or headrest; Fig. 12a shows a schematic sectional view of the arrangement of a primary foam housing in a main foam element of a vehicle seat in an initial state; Fig. 12b the arrangement according to the Fig. 12a in a displaced state; and Fig. 12c a variant of the arrangement according to the Fig. 12a with form elements with fastening interface.

[0051] In the figures, identical reference symbols designate identical or essentially equivalent elements or groups of elements. Detailed description of preferred embodiments

[0052] The Fig. 1a and Fig. 1b shows the basic principle of an auxetic material 50, which consists of a plurality of cells 51 of the same configuration that are coupled to one another, in particular formed integrally with one another. The auxetic material is a three-dimensional structure, for example, formed as a diamond-folded structure or foam, which can be suitably manufactured using suitable methods, such as an injection molding process, a lamination process, or a 3D printing process. Auxetic materials made of a plastic material are preferred.

[0053] The Fig. Figure 1a shows the auxetic material 50 in an initial state, in which the individual cells 51 have a diamond-shaped cross-section. The cells 51 are connected to one another via longitudinal webs that run parallel to the first direction x1, and via transverse webs 53 that run at an acute angle to the second direction x2 and to the first direction x1. Due to the honeycomb structure with many spaces in the cells 51, a stretching of the auxetic material 50 in the first direction x1, i.e. a tensile force in the first direction x1, causes an expansion or widening of the auxetic material 50 in the second direction x2, perpendicular to the first direction x1, as indicated by the arrows in the Fig. 1b, which shows the expanded final state of the auxetic material 50 at maximum expansion in the second direction x2. In this final state, the transverse webs 53 are folded upward and extend parallel to the second direction x2. As indicated by the dashed reference lines, the expansion of the individual cells 51 results in an overall expansion or widening of the auxetic material 50 in the second direction x2.

[0054] This effect is utilized according to the invention for adjusting seat elements or seat sections in a vehicle seat. The aforementioned expansion in the second direction x2 can be maintained by the auxetic material 50 in the final state, even when larger forces act in the second direction x2, because the cells 51 are maximally expanded in the second direction x2 in the final state and wish to remain in this energetically stable position. The expanded position can thus, in principle, also be maintained without fixing this position, for example by blocking an adjustment device (not shown). Only when the forces in the second direction x2 exceed a material-dependent threshold value is the auxetic material 50 compressed again in the second direction x2. However, this compression in the second direction x2 can be blocked mechanically, for example by blocking the adjustment device.

[0055] In practice, it has proven particularly useful if the auxetic material 50 is not adjusted to its respective maximum end positions, i.e., to an initial state of maximum compression in the second direction x2 and a final state of maximum expansion, but rather if the adjustment of the auxetic material 50 is limited by the design of the adjustment device in good time before reaching the aforementioned respective end positions. Because the dependence of the expansion of the auxetic material 50 in the second direction x2 on the stretching in the first direction x1 usually follows a trigonometric function, for example, approximately a sine function, an approximate linear expansion of the auxetic material 50 in the second direction x2 can be achieved by suitably limiting the adjustment in the first direction x1.

[0056] Fig. Figure 2a schematically shows the combination of several basic units 50 made of an auxetic material to form a larger unit 54 for use as a medium for adjusting the hardness or inner contour of a vehicle seat according to the present invention. The basic units 50 can be combined with each other in almost any way in the first and second directions, as well as in a direction perpendicular thereto, by selecting a suitable manufacturing method, whereby not only rectangular material blocks, as in the right part of the figure, Fig. 2a, but also material blocks with any other contour can be realized. For example, auxetic materials can be realized in this way which have a circular or elliptical profile in a plane spanned by the first and second directions x1, x2 or whose profile is suitably rounded at a front and / or rear end. Such profiles can be easily adapted to the geometric requirements in the seating area. For example, adjustment units with a circular or elliptical cross-section are preferred as lumbar supports or pads at the front end of vehicle seats. Even for the larger material blocks formed in this way from an auxetic material 50, the property of expansion in the second direction x2 remains when the auxetic material 50 is stretched in the first direction x1 perpendicular thereto.

[0057] The Fig. Figure 2b illustrates in a schematic perspective view the basic principle of incorporating a block 54 made of an auxetic material into an adjustment device according to the present invention. In the upper part of the figure, the Fig. 2b the adjustment device with the block 54 made of an auxetic material in a non- or only slightly expanded initial state, comparable to the Fig. 1a, while the lower part of the image shows the Fig. 2b the adjustment device with the block 54 made of an auxetic material in a widened final state, comparable to Fig. 1b. Tension webs 55 protrude from the two ends of the block 54 made of the auxetic material, which are opposite one another in the first direction x1, and are suitably coupled to the adjustment device via fastening sections 56, as explained in more detail below. Preference is given to geometries in which the fastening sections 56 are fixedly mounted at a first end of the block 54 made of the auxetic material, for example fastened to a stationary fastening section, while the fastening sections 56 at the second end of the block 54 made of the auxetic material, which is opposite in the first direction x1, are coupled to an adjusting member that is adjustable in the first direction x1 in order to stretch or compress the block 54 made of the auxetic material in the first direction x1, which is translated by the auxetic material into a corresponding expansion or compression of the block 54 in the second direction x2.

[0058] How to compare the two in the Fig. 2b, the tension webs 55 and fastening sections 56 can run essentially parallel and spaced from one another in the first direction x1 in a state with minimal expansion of the block 54 made of the auxetic material in the second direction x2, while the widening of the block 54 made of the auxetic material in the state with greater expansion of the block 54 made of the auxetic material in the second direction x2 results in at least some of the tension webs 55 and fastening sections 56 extending at an angle to the first direction x1. At the same time, this results in a certain stretching of the tension webs 55 and fastening sections 56, which must be taken into account by selecting suitable elastic materials in these sections.Overall, the block 54 made of the auxetic material, as well as the tension bars 55 and fastening sections 56, must have sufficient freedom of movement in the second direction x2, which must be taken into account in the geometric design of the adjustment device. The inclined course of the tension bars 55 and fastening sections 56 in the state with greater expansion of the block 54 made of the auxetic material can generally be used for further contouring of the seat section to be adjusted.

[0059] The Fig. Figure 2c shows three examples of contouring the seat section to be adjusted by the geometry of the cells 51 or basic units 50 made of the auxetic material. In the left part of the image, Fig. 2c shows an example in which a central section of the block 54 made of the auxetic material is higher than a front or rear section, viewed in the first direction x1. A cover 58 arranged in this region, which connects the two blocks 54 to one another, in particular is connected to them, and which consists of an elastic material, automatically forms an inclined section 58, the inclination of which depends on the expansion of the blocks 54 in the second direction x2. This inclined section 58 can, for example, be provided at or near the front edge of the seat pan of a vehicle seat in order to give this area a suitable profile. The middle part of the image of Fig. Figure 2c shows the same block 54 made of the auxetic material with a smaller extension in the second direction x2. The lower inclination of the inclined section 58 is clearly visible.

[0060] The right-hand part of the image is based on an embodiment in which the heights of the cells 51 or basic units of the block 54 made of the auxetic material are different. However, for each column of cells 51 extending in the second direction x2, the height of the cells 51 is identical. The right-hand part of the image of the Fig. Figure 2c compares a state with minimal extension in the second direction x2 with a state with greater extension in the second direction x2. In the state with minimal extension in the second direction x2, the height of the two columns of cells 51 is identical, resulting in a horizontal contour in the area of ​​the cover 57. While in the state with greater extension in the second direction x2, the right column of cells 51 has expanded more, resulting in an oblique contour in the area of ​​the cover 57. This effect can also be used to contour the seat section to be adjusted.

[0061] The Fig. 3a and Fig. 3b show a schematic sectional view of the basic structure of an adjustment device 1 according to the present invention. The block 54 made of the auxetic material is accommodated in a casing 2, which allows expansion in the second direction x2, but holds the block 54 together to ensure a flat compressive load when adjusting the block 54. According to the Fig. 3a, the block 54 made of the auxetic material is arranged between two plates 3, 4, which can be pivoted relative to one another about a pivot axis extending parallel to the first direction in order to adjust the included opening angle. The base plate 3 can be mounted in a stationary manner, for example, fixedly connected to a section of a frame of the vehicle seat, while the plate 4 is mounted such that it can be pivoted relative to it, for example on a hinge or joint extending in the first direction x1. By adjusting the block 54 made of the auxetic material, the adjustable plate 4 is thus pivoted further about the bearing area, which can be used indirectly to adjust the contour and / or hardness of a seat section of a vehicle seat.

[0062] According to the Fig. 3b, the block 54 made of the auxetic material is further arranged in a tubular sheath 5 with a longitudinal axis extending parallel to the first direction x1 and with a circumferentially formed outer surface, and is permanently in contact with the inside of the sheath 5. The sheath 5 is preferably made of an elastic material, for example, as an elastic plastic tube, which elastically prestresses the block 54 into its minimally expanded initial position. Fig. 3b, an expansion of the block 54 made of the auxetic material in its casing 2 leads to an expansion of the casing 5 in the first direction 5, which leads to a change in the outer contour of the casing 5 and can thus be used for a direct adjustment of the contour and / or hardness of a seat section of a vehicle seat.

[0063] Fig. Figure 4a shows the basic structure of an adjustment unit 1 according to a first embodiment of the present invention in a schematic sectional view in an initial state with minimal extension in the first and second directions. A block 54 made of an auxetic material is accommodated in a casing 2. The first direction (tension direction) extends in the Fig. 4a horizontally from left to right. One end of the block 54 made of the auxetic material is connected to a holding section 15, for example a holding clamp, as explained in more detail below, via fastening sections 16, for example clamp connections, screw connections, materially bonded or welded connections, or the like. At the other end of the block 54 made of the auxetic material, opposite in the first direction, the tension webs 55 are connected to a tension element 10. In this exemplary embodiment, an electric spindle drive is used as the actuating device 9. The spindle 11 can be driven by an electric motor 14 serving as the drive device, and which meshes with a spindle nut 10 that is coupled to the tension element 10 or preferably forms the latter. The electric motor 14 is fastened to a stationary counter-element 13.Rotation of the threaded spindle 11 thus leads to an adjustment of the spindle nut 10 and the tension element, thus resulting in a tensile force exerted on the tension webs 55 and an expansion of the block 54 made of the auxetic material in the first direction. The cells of the block 54 made of the auxetic material press against the elastic, expandable casing 2, which leads to an expansion of the casing 2 in the second direction, as shown in FIG. Fig. 4b. The upper and lower sides of the casing 2 can generally be parallel, which leads to an increase in the distance between the upper and lower sides of the casing 2. Due to the widening of the block 54 made of the auxetic material, an overall elliptical curvature of the casing 2 can also occur, as shown in the Fig. 4b, i.e. a change in the outer profile of the adjustment device 1.

[0064] In a currentless state of the electric motor 14, it is preferably blocked, so that the position once assumed in the first direction x1 is unchangeable and thus the contour of the adjustment device 1 is maintained until the electric motor 14 is actuated again. In order to return to the starting position according to the Fig. 4a, the tension element 10 can be elastically preloaded into the initial position, for example by means of a compression spring 12 in which the threaded spindle 11 is accommodated and which elastically preloads the counter-element 13 and the tension element 10 against each other. However, a comparable restoring force back to an initial position can in principle also be exerted directly by the elastic properties of the casing 2 of the block 54 made of the auxetic material or a casing of the adjustment device 1.

[0065] Fig. Figure 5a shows a perspective view of the basic structure of an adjustment unit 1 with a motor-driven spindle drive according to a second embodiment of the present invention. The tension webs 55 of the block 54 made of the auxetic material are attached at a first end directly to the base leg of a U-shaped retaining clip 15, while the tension webs 55 are attached at the opposite second end directly to a tension element 10, which is either coupled to a spindle nut of the spindle drive or preferably directly forms one. As shown in the Fig. As shown in Figure 5a, several blocks 54 made of the auxetic material are held parallel to one another in the U-shaped retaining clamp 15 and secured together in the manner described above. A mirror-symmetrical mounting with respect to a plane in which the threaded spindle 11 extends is preferred. Adjusting the electric motor 14a in the manner described above leads to a uniform expansion of all blocks 54 in the second direction.

[0066] The Fig. 5a and Fig. 5b show in a schematic sectional view the adjusting device 1 after the Fig. 5a in an initial state and an adjusted state. The block 54 made of the auxetic material is accommodated between two cover plates 18 aligned parallel to each other. These are guided in the second direction, for example by means of holes comparable to the holes 17 in the retaining clip according to the Fig. 5a, so that an expansion of the block 54 made of the auxetic material in the second direction leads to a change in the distance between the two cover plates 18. Elastic cover sections 19 are provided at the front and rear ends of the block 54 made of the auxetic material, which are increasingly stretched as the block 54 made of the auxetic material expands in the second direction, resulting in an oblique or rounded outer contour at the front and rear ends of the adjustment device 1 and can be utilized to further profile the seat sections to be adjusted. The casing 2 and cover sections 19 serve to equalize the adjustment forces acting on the associated section of the vehicle seat, for example, on a foam housing.

[0067] The Fig. 6 shows further details of the mounting of the tension element 10 in an adjusting device with spindle drive according to the Fig. 4a to Fig. 5c. The threaded spindle 11 extends through a central bore 10a in the tension element 10. The fastening recesses 10b for fastening the tension webs of the blocks 54 (cf. Fig. 5a) are arranged mirror-symmetrically with respect to a mirror plane containing the threaded spindle. Guide lugs 10c (or guide recesses) are formed on both sides of the tension element 10. These guide lugs engage in corresponding guide grooves 15a (or guide lugs) formed on the two side legs of the retaining clip 15 and interact with them in a form-fitting manner to ensure straight guidance of the tension element 10 in the first direction when the threaded spindle 11 is adjusted.

[0068] Instead of an electric drive, any other drive can be used according to the present invention, for example mechanical or pneumatic drives. Fig. Figure 6b shows an example of coupling the Bowden cable of a mechanical drive with an adjusting device according to the present invention. The Bowden cable sheath 20 is mounted centrally on a stationary leg of the retaining clip 15. The pull cable 21 extends through a central bore in this leg to the pull element 10, which is connected in a corresponding manner as described above with reference to Fig. 6a, is guided and supported on the side legs of the retaining clip 15. The nipple of the tension cable 21 is attached to the tension element 10 by means of a clamping element 22 or the like. Adjusting the tension cable 21 in the first direction results in a corresponding adjustment of the tension element 10 in the first direction and thus in a corresponding expansion or compression of the auxetic material in the second direction.

[0069] In principle, several adjustment devices according to the present invention can also be adjusted jointly by a common actuating device, in particular synchronously with each other. Fig. Figure 7a illustrates this using an example with mechanical adjustment by a Bowden cable. The Bowden cable sheath 20 is mounted centrally on a stationary leg of a central retaining clip 25. The pull cable 21 extends through a central bore in this leg to a central pull element 26, which is arranged in a corresponding manner as described above with reference to Fig. 6a, is guided and mounted on the side legs of the central retaining clamp 25 (i.e., by engagement of the lateral guide lugs 26c of the central tension element 26 in correspondingly formed guide grooves 25a in the side legs of the central retaining clamp 25). The nipple of the tension cable 21 is fastened to the central tension element 26 by means of a clamping element 22 or the like. Furthermore, a retaining clamp 27 is provided on the central tension element 26, to which the first ends of coupling tension cables 28 are fastened, which act in the manner of the tension cable of an adjusting device, as described above with reference to Fig. 6b, and whose second ends are thus coupled to the central tension element 10 of a respective adjusting device 1.

[0070] When the central tension cable 21 is adjusted by the central actuating device 24, the central tension element 26 is initially adjusted and subsequently the coupling tension cables 28 are synchronously adjusted, which in turn causes the tension elements 10 of the adjusting devices 1 to be synchronously adjusted in the first direction and thus leads to a corresponding expansion or compression of the auxetic material in the second direction.

[0071] A corresponding synchronous adjustment can also be achieved for other types of central drive 24. For example, the central drive can also be a spindle drive driven by an electric motor 14a, which leads to a synchronous adjustment of two or more downstream adjustment devices 1, as in the Fig. 7b is shown schematically.

[0072] This principle can be used, for example, for the synchronous adjustment of both side bolsters in the area of ​​a seat pan or backrest of a vehicle seat. By adjusting the gear ratios when coupling the central tension element 26 with the downstream adjustment devices 1, a different adjustment of the downstream adjustment devices 1 can also be achieved. For example, the gear ratios of the coupling of the central tension element 26 with the downstream adjustment devices 1 can be suitably adjusted by mechanically adjusting a rotary knob or by means of an electric motor.

[0073] The Fig. 8a and Fig. 8b show a schematic sectional view of the arrangement of an adjustment unit 1 according to the present invention in a primary foam housing 30 of a vehicle seat. The adjustment unit is of a construction as described above with reference to Fig. 4a to Fig. 7c. An adjustable cover plate 18 is provided on the upper and lower contact surface between the adjustment unit 1 and the primary foam housing 30. This compensates for relative movements and different pressure points of the auxetic material over a large area and thus makes them uniform. The adjustment unit 1 is surrounded by a primary foam housing 30, the contour of which is tailored to the respective requirements of the vehicle seat. The primary foam housing 30 has a suitably profiled front end piece 37 at its front end and a suitably profiled rear end piece 38 at its rear end, which are not adjusted or deformed, or at most only insignificantly, when the auxetic material expands in the second direction. As shown in the Fig. 8b for the adjusted state, however, the central section of the primary foam enclosure 30 is raised or widened due to the expansion of the auxetic material and the corresponding adjustment of the cover plates 18. The adjustment of the cover plates occurs parallel to each other in the central area.

[0074] A corresponding wedge-shaped spreading of the primary foam housing 30 can be used for an adjustment unit with the structure according to the Fig. 3a in a corresponding manner.

[0075] The Fig. 9a shows, in a perspective exploded view, the structure of a primary foam housing 30 with an adjustment unit and motor-driven spindle drive according to a further embodiment of the present invention. The adjustment unit 1 is accommodated between an upper cover plate 18a and a lower cover plate 18b made of a rigid or flexible material in a central receptacle 34b of the primary foam housing 30. The cover plates 18a, 18b are each accommodated in an upper or lower receptacle 34a or 34c provided above or below the central receptacle 34b. The width of the central receptacle 34b is greater than that of the upper or lower receptacles 34a or 34c, which is due to the greater width due to the side legs of the retaining clip 15. The upper or lower receptacles 34a or 34c have a rectangular profile.The side walls of the receptacles 34a, 34c thus ensure that the cover plates 18a, 18b are guided straight therein when the adjustment unit 1 is adjusted. As shown in the . Fig. As shown in Fig. 9, guide holes 15b, 18c can be formed at the ends of the retaining clip 15 and the cover plates 18a, 18b, which are guided on rods or the like.

[0076] In an initial state with minimal width of the blocks 54 made of auxetic material in the second direction, the cover plates 18a, 18b can essentially bear against the inner surfaces of the primary foam housing 30. Upon adjustment of the adjustment unit 1 and expansion of the blocks 54 made of auxetic material in the second direction, the cover plates 18a, 18b press further against the inner surfaces of the primary foam housing 30, which leads to a corresponding expansion of the primary foam housing 30 and thus to a corresponding deformation of the primary foam housing 30. This not only allows the outer contour of the primary foam housing 30 to be changed, but also the hardness of the primary foam housing 30, for example when the foamed material of the primary foam housing 30 becomes harder in a direction perpendicular to the first and second directions x1, x2 due to expansion in the second direction x2.

[0077] As in the Fig. As shown schematically in Figure 9, the top and bottom of the primary foam housing 30 can also be flattened. Due to the deformation during adjustment of the adjustment unit 1, such a primary foam housing 30 with a flattened top and bottom can also change into a state as shown in the upper part of the figure. Fig. 9, in which the profile of the primary foam enclosure 30 is then essentially circular.

[0078] The Fig. 10a and Fig. 10b show the structure and mode of operation of a flap adjuster according to a further embodiment of the present invention, as described above with reference to Fig. 3a has already been described schematically. The blocks 54 made of auxetic material are accommodated between the base plate 3 and the pivotally mounted adjustable plate 4. Spacer elements 6 ensure a minimal distance between the two plates 3, 4 and thus prevent excessive compression of the auxetic material, which could otherwise lead to its destruction. Upon adjustment of the electric motor 14a and an associated spindle drive, the blocks 54 made of auxetic material are expanded in the second direction, which leads to the two flaps 3, 4 folding apart. Such an adjustment unit is accommodated in a primary foam housing (not shown) in the manner described above, wherein the cover plates 18a, 18b (cf. Fig. 9) are now replaced by the two flaps 3 , 4.

[0079] The Fig. 11a shows the basic structure of a frame 40 for a vehicle seat according to the present invention, comprising a seat pan 42 and a backrest 41, wherein at least one device 71-74 for adjusting the hardness and / or geometry of seat elements of the vehicle seat is attached to the frame. Side bolsters 42b are provided on the seat pan 42, and side bolsters 41b are provided on the backrest 41. In the area of ​​the side bolsters 41b of the backrest 41, adjustment devices 72 for adjusting the hardness and / or geometry of the vehicle seat in this area are provided. In the area of ​​the side bolsters 42b of the seat pan 42, adjustment devices 71 for adjusting the hardness and / or geometry of the vehicle seat in this area are provided. At the front edge of the seat pan 41, a further adjustment device 70 for adjusting the hardness and / or geometry of the vehicle seat in this area is provided.In the central area of ​​the backrest 41, three adjustment devices 72 are provided for adjusting the hardness and / or geometry of the vehicle seat in this area, acting as adjustable lumbar supports. At the upper end of the backrest 41, a headrest connecting section 44 is provided, via which a headrest 47 can be connected to the frame 40 or the vehicle seat. As shown in FIG. Fig. 11b, adjustment devices 74 for adjusting the hardness and / or geometry in this area can also be provided in the headrest body 48 or in a primary foam body thereof.

[0080] The adjusting devices 70 - 74 are connected via at least one support element, for example a metal bolt, to an associated section of the seat pan 42 or the backrest 41 or the headrest module 47 connected or connectable to the frame 40 and are mounted in a stable manner, as shown schematically in the Fig. 12b shown.

[0081] Fig. Figure 12a shows a schematic sectional view of the arrangement of a primary foam housing 30 in a main foam element 81 of the lower part 80 of a vehicle seat in an initial state. A recess is formed in the main foam element 81, in which the primary foam housing 84 is received with the adjustment unit 1. The upper side 82 of the main foam element 81 has a suitable contour and is raised in a central region thereof by adjusting the adjustment unit 1 to form a deformed section 87 in the central region, as shown in Figure 1. Fig. 12b shown.

[0082] The Fig. Figure 12c shows a further embodiment in which the primary foam housing 84 further comprises shaped elements 86 at a front and / or rear end, which further influences the properties of the primary foam housing 84 when adjusting the auxetic material. Supply lines 85 to the adjustment unit can be led out via the rear end or the underside of the main foam element 81. The adjustment unit with the primary foam housing 84 is attached to the seat pan of the vehicle seat frame via support elements 88, whereby a point-like or even planar support can be realized on the seat pan, on the frame, or on a foam pad. As indicated by the dashed line in the Fig.12c, the main foam element 81 can have a separation point for assembly at a suitable location, for example for spreading or folding open the main foam element 81 in order to insert the adjustment unit or the adjustment unit together with the primary foam housing into a recess in the main foam element 81, for example from the underside of the main foam element 81.

[0083] As will be apparent to those skilled in the art upon studying the above description, the use of an auxetic material significantly simplifies the construction of devices for adjusting the hardness and / or geometry of seat elements of a vehicle seat, in particular a motor vehicle seat. Suitable auxetic materials for this purpose include, in principle, any prior art auxetic materials, in particular diamond-fold structures made of a plastic material, in particular produced by means of an injection molding or lamination process. Composite materials with a plastic component or foams with auxetic properties are also generally suitable. Due to the further technical advances in 3D printing processes, it is expressly contemplated that an auxetic material for use in accordance with the present invention can also be produced by suitable 3D printing processes, in particular from a plastic.The inventor’s corresponding experiments have fundamentally confirmed the suitability of 3D printing processes for this purpose. List of reference symbols 1 adjustment unit / adjustment device 2 Wrapping 3 Base plate 3a Side panel of base plate 4 adjustable plates 4a Side panel of adjustable plate 5 Bubble / Envelope 6 spacer element 7 Hinge 9 Actuating device 10 Spindle nut / tension element 10a central hole 10b Mounting recess 10c guide nose 11 Threaded spindle 12 compression spring 13 stationary counter element 13a central hole 13b Mounting recess 13c Guide nose 14 Rotary drive 14a Electric motor 15 Retaining clip / retaining frame 15a Guide groove 15b Guide hole 16 Fastening section 17 Mounting hole 18 Cover plate 18a upper cover plate 18b lower cover plate 18c guide hole 19 elastic cover section 20 Bowden cable sheath 21 Pull rope 22 nipple clamp element 24 Actuating device 25 central retaining clip 25 guide groove 26 central tension element 26c guide nose 27 Retaining clip 28 Coupling pull rope 30 primary foam enclosure 31 recording 32 z-inner contour 33 Transverse inner contour 34a upper shot 34b central recording 34c lower shot 37 profiled front end piece of primary foam enclosure 38 profiled rear end piece of primary foam enclosure 40 Motor vehicle seat 41 Backrest 41a Backrest frame 41b sidewall 42 seat pan 42a Seat pan frame 42b sidewall 43 Front edge of seat pan 44 Headrest connecting section 45 seat rail 46 bar rod 47 Headrest 48 headrest bodies 50 auxetic material, basic unit made of auxetic material 51 Cell 52 Longitudinal web 53 Crossbar 54 block of auxetic material 55 Tension bridge / coupling section 56 fastening section 57 Cover with optional straight or inclined contour 58 Cover with inclined contour 70 Adjustment unit on the front edge of the seat pan 71 Adjustment unit on side bolsters of seat pan 72 Lumbar support element 73 Adjustment unit on side bolsters of backrest 74 Adjustment unit in headrest 80 seat base 81 Main foam element 82 Top 83 leading edge 84 Upholstery tube with adjustment device 85 supply lines 86 form elements 87 deformed section 88 Support element x1 first direction / direction of travel x2 second direction / expansion direction

Claims

[1] Device for adjusting the hardness and / or geometry of seat elements of a vehicle seat with an adjusting device (1; 70-74) for adjusting the hardness and / or geometry of a seat element of the vehicle seat, and an actuating device (9) for actuating the adjusting device (1; 70-74), characterized by that the adjusting device (1; 70-74) comprises an auxetic material (50) and is designed such that, upon actuation by the actuating device (9), a tensile force is exerted on the auxetic material (50) in a first direction (x1), thereby causing an elongation of the auxetic material (50) in the first direction (x1) and a widening of the auxetic material (50) in a second direction (x2) transverse to the first direction (x1) in order to adjust the hardness and / or geometry of the seat element of the vehicle seat, wherein a height of the auxetic material (50) in the second direction (x2) is different at least in sections, so that a surface of the auxetic material (50) has a curved or beveled contour at least in sections. [2] Device according to claim 1, wherein the auxetic material (50) acts at least partially on an adjustment surface (4, 5) when expanded in the second direction (x2) in order to adjust the hardness and / or geometry of the seat element of the vehicle seat. [3] Device according to claim 2, wherein the adjustment surface (4) is plate-shaped and is tilted or further adjusted in the second direction (x2) upon expansion of the auxetic material (50) in the second direction (x2). [4] Device according to claim 3, wherein the adjustment surface (4) is pivotally mounted relative to a stationary base surface (3), wherein the auxetic material (50) is arranged between the stationary base surface (3) and the pivotally mounted adjustment surface (4), so that the adjustment surface (4) is pivoted relative to the stationary base surface (3) when the auxetic material (50) expands in the second direction (x2). [5] Device according to claim 2, wherein the adjustment surface (4) has two sections on two sides of the auxetic material (50) which are opposite to each other in the second direction (x2), wherein a distance between the two sections is increased upon expansion of the auxetic material (50) in the second direction (x2). [6] Device according to claim 5, wherein the adjustment surface (4) is designed to be circumferential or substantially circumferential in a sectional view perpendicular to the first direction (x1) and is made at least in sections of an expandable material, so that upon expansion of the auxetic material (50) in the second direction (x2) a volume enclosed by the adjustment surface (4) is increased. [7] Device according to claim 6, wherein the adjusting surface (4) is designed as a tube made of an expandable material, the longitudinal axis of which extends parallel to the first direction (x1). [8] Device according to one of the preceding claims, wherein the auxetic material (50) has a plurality of coupling sections (56, 57) for coupling to the actuating device (9), wherein the actuating device (9) applies the tensile force in the first direction (x1) jointly to all coupling sections (56) to cause the elongation of the auxetic material (50) in the first direction (x1) and widening of the auxetic material (50) in the second direction (x2) transverse to the first direction (x1). [9] Device according to claim 8, wherein the plurality of coupling sections (56, 57) comprises first coupling sections (56) which are fixedly mounted on a first side of the auxetic material (50), and second coupling sections (57) which are adjustably mounted on a second side of the auxetic material (50) which is opposite to the first side in the pulling direction (x1) and are coupled to the actuating device (9). [10] Device according to claim 9, wherein the first coupling sections (56) are jointly fastened to a holding clamp (15) and wherein the second coupling sections (57) are jointly fastened to a pulling element (10) which is mounted such that the pulling element (10) is adjusted in the first direction (x1) when actuated by the actuating device (9) relative to the holding clamp (15), wherein the holding clamp (15) is designed to be open at least on one side in the second direction (x2). [11] Device according to claim 10, wherein the holding clamp (15) is designed as a U-shaped section of a holding frame which jointly encloses the tension element (10) and the auxetic material (50) in a plane which is parallel to the first tension direction (x1). [12] Device according to claim 10 or 11, wherein the pulling element (10) has, on two sides which are opposite one another in a direction perpendicular to the first and the second direction (x1, x2), guide lugs (10c) or guide grooves which engage in correspondingly formed guide grooves (15a) or guide lugs of the holding clip (15), so that the pulling element (10) is guided in the first direction (x1). [13] Device according to one of claims 10 to 12, with a plurality of holding clamps (15) and associated pulling elements (10) for the simultaneous adjustment of a plurality of adjusting devices (1; 70-74), wherein the actuating device (9) is coupled to a central pulling element (26) and the central pulling element (26) is coupled to the plurality of associated pulling elements (10), so that upon actuation of the actuating device (9), all associated pulling elements (10) are adjusted synchronously. [14] Device according to claim 13, wherein the central pulling element (26) has guide lugs (26c) or guide grooves on two opposite sides, which engage in correspondingly designed guide grooves (25a) or guide lugs of a central holding clamp (25), so that the central pulling element (26) is guided in the central holding clamp (25), and the central tension element (26) is coupled to all associated tension elements (10) via coupling tension cables (28). [15] Device according to one of the preceding claims, wherein the actuating device (9) is designed as a spindle drive which has a spindle (11) which can be driven by a drive device (14, 14a) and which meshes with a spindle nut (10) which is coupled to the pulling element (10) or to the central pulling element (26) or forms this. [16] Device according to one of claims 1 to 14, wherein the actuating device (9, 24) adjusts a pull cable (21) of a Bowden cable (20), wherein the pull cable (21) is coupled to the pull element (10) or to the central pull element (26). [17] Device according to claim 15 or 16, wherein the tension element (10) or the central tension element (26) is pretensioned into an initial position by means of a return element. [18] Device according to one of the preceding claims, wherein the adjusting device (1; 70-74) stretches the auxetic material (50) in the first direction (x1) between a first predetermined position and a second predetermined position, wherein an outer dimension of the auxetic material (50) in the second direction is larger in the second predetermined position than in the first predetermined position. [19] Device according to claim 18, wherein the auxetic material (50) is prestressed in the first direction (x1) by means of a return element into the first position, wherein the actuating device (9) is lockable. [20] Device according to claim 18 or 19, wherein the auxetic material (50) is formed from a plurality of cells (51) of the same basic shape, which are connected to one another to form a block of material, wherein the cells (51) are assigned a first dead center with a first width of the cells (51) in the second direction (x2) and a second dead center with a second width of the cells (51) in the second direction (x2) which is greater than the first width, a dependence of the width of the cells (51) in the second direction (x2) on the extension of the cells (51) in the first direction (x1) follows a predetermined function, and the actuating device (9, 24) is designed so that, with a linear adjustment of the adjusting device (1; 70-74), the adjustment of the width of the cells (51) in the second direction (x2) essentially follows a linear function. [21] Device according to claim 20, wherein the actuating device (9, 24) is a mechanical actuating device to which a control cam with a non-linear control curve is assigned for controlling the tensile force in the first direction (x1), or wherein the actuating device (9, 24) is an electrically or pneumatically operated actuating device to which an electronic control with a memory is assigned, wherein a characteristic curve of the predetermined function is stored in the memory and the electronic control controls the actuating device (9, 24) such that, upon a linear adjustment of the adjusting device (1; 70-74), the adjustment of the width of the cells (51) in the second direction (x2) essentially follows a linear function. [22] Device according to claim 20 or 21, wherein in the first position of the auxetic material (50), the first width of the cells (51) in the second direction (x2) is greater than a minimum width of the cells (51) in the second direction (x2) and / or in the second position of the auxetic material (50), the second width of the cells (51) in the second direction (x2) is smaller than a maximum width of the cells (51) in the second direction (x2). [23] Device according to one of the preceding claims, wherein the height of the auxetic material (50) is lower at a front and / or rear end, viewed in the first direction (x1), than at a central portion of the auxetic material (50). [24] Device according to one of the preceding claims, wherein the auxetic material (50) is made as a diamond-fold structure from a plastic material. [25] Frame (40) for a vehicle seat, comprising a seat pan (42) and a backrest (41), wherein at least one device (71-74) for adjusting the hardness and / or geometry of seat elements of the vehicle seat is attached to the frame (40), characterized bythat the at least one device (71-74) for adjusting the hardness and / or geometry of seat elements of the vehicle seat is designed as a device for adjusting the hardness and / or geometry of seat elements of a vehicle seat according to one of claims 1 to 24. [26] Frame (40) according to claim 25, wherein the device (71-74) for adjusting the hardness and / or geometry of a seat element of the vehicle seat is designed as a device (71, 73) for adjusting the curvature and / or width of side bolsters of a seat base (80) or the backrest (41), as a device for adjusting an upper backrest part of a split backrest, as a device (72) for adjusting a lumbar support, as a device (70) for adjusting a leg support of the seat base (80) or as a device (74) for adjusting the hardness and / or geometry of a headrest module (47) connected or connectable to the frame (40). [27] Frame (40) according to claim 25 or 26, wherein the device (71-74) for adjusting the hardness and / or geometry of a seat element of the vehicle seat is connected via at least one support element (88) to an associated section of the seat pan (42) or the backrest (41) or a headrest module (47) connected or connectable to the frame (40). [28] Vehicle seat, comprising a frame (40) having a seat pan (42) and a backrest (41), wherein at least one device (71-74) for adjusting the hardness and / or geometry of a portion of the vehicle seat is attached to the frame (40), and wherein the seat pan (42) and the backrest (41) are each provided with a main foam element (81) to form a seat base (80) and a back part of the vehicle seat (40), characterized bythat the at least one device (71-74) for adjusting the hardness and / or geometry of the seat element of the vehicle seat is designed as a device for adjusting the hardness and / or geometry of the seat element of a vehicle seat according to one of claims 1 to 24, which is received in a recess in the main foam element (81). [29] Vehicle seat according to claim 28, wherein the at least one device (71-74) for adjusting the hardness and / or geometry of the seat element of the vehicle seat is accommodated in a primary foam housing (84; 30) which is accommodated in the recess in the main foam element (81). [30] Vehicle seat according to claim 28 or 29, wherein the primary foam housing (84; 30) has a profiled front end piece (37) and / or a profiled rear end piece (38). [31] Vehicle seat according to claim 29 or 30, wherein the auxetic material (50) in the primary foam housing (84; 30) is covered with an upper cover plate (18a) and / or a lower cover plate (18b) to compensate for relative movements and different pressure points of the auxetic material (50). [32] Vehicle seat according to claim 31, wherein the auxetic material (50) is accommodated with the adjusting device (1; 70-74) in a central receptacle (34b) of the primary foam housing (84; 30), the upper cover plate (18a) or the lower cover plate (18b) is movably guided in an upper receptacle (34a) or a lower receptacle (34c) above or below the central receptacle (34b) in the second direction (x2), and a width of the central receptacle (34b) in a direction perpendicular to the first and second directions (x1, x2) is greater than a width of the upper and lower receptacles (34a, 34c) in the direction perpendicular to the first and second directions (x1, x2). [33] Vehicle seat according to claim 31 or 32, wherein the upper or lower cover plate (18a, 18b) is connected at its front and / or rear end, viewed in the first direction (x1), to a retaining clip (15) of the adjusting device (1; 70-74) via an elastic cover section (19). [34] Vehicle seat according to claim 33, wherein at the front and / or rear end of the retaining clip (15) of the adjusting device (1; 70-74), viewed in the first direction (x1), positioning holes (15b) are provided, and / or at the front and / or rear end of the upper or lower cover plate (18a, 18b) viewed in the first direction (x1), guide holes (18c) are provided for guiding the upper or lower cover plate (18a, 18b) in the second direction (x2). [35] Vehicle seat according to one of claims 30 to 34, wherein the primary foam enclosure (84; 30), viewed in a sectional view perpendicular to the first and second directions (x1, x2), has a circular profile, or an upper side and / or lower side of the primary foam housing (84; 30) is flattened when viewed in the second direction (x2). [36] Vehicle seat according to one of claims 28 to 34, wherein the vehicle seat is a motor vehicle seat. [37] Use of an auxetic material (50) for a device for adjusting the hardness and / or geometry of seat elements of a vehicle seat, wherein a tensile force in a first direction (x1) is exerted on the auxetic material (50) by an adjusting device (1; 70-74), thereby causing an extension of the auxetic material (50) in the first direction (x1) and an expansion of the auxetic material (50) in a second direction (x2) transverse to the first direction (x1) in order to adjust the hardness and / or geometry of the seat element of the vehicle seat, wherein a height of the auxetic material (50) in the second direction (x2) is different at least in sections, so that a surface of the auxetic material (50) has a curved or bevelled contour at least in sections. [38] Use according to claim 37, wherein the auxetic material (50) has a plurality of coupling sections (56, 57), wherein the tensile force in the first direction (x1) is applied jointly to all coupling sections (56) to cause the elongation of the auxetic material (50) in the first direction (x1) and widening of the auxetic material (50) in the second direction (x2) transverse to the first direction (x1). [39] Use according to claim 38, wherein the plurality of coupling sections (56, 57) comprises first coupling sections (56) which are fixedly mounted on a first side of the auxetic material (50), and second coupling sections (57) which are adjustably mounted on a second side of the auxetic material (50) which is opposite to the first side in the tensile direction (x1), wherein the tensile force is applied to the second coupling sections (57) of the auxetic material (50).

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