Force sensor element, method for producing such a force sensor element and force sensor arrangement

Abstract

The present invention relates to a method for producing a force sensor element (102) and a force sensor element that can be produced accordingly and a force sensor arrangement (100) equipped therewith, wherein an expansion plate (108) with four resistance regions (112) that are connected to one another in an electrically conductive manner in a ring and four taps (114) that are each arranged between two of the resistance regions (112) is formed from a piece of electrically conductive sheet metal, wherein the expansion plate (108) is embedded in a bedding (110) made of an electrically insulating material, so that the taps (114) can be electrically contacted to form a bridge circuit.

Description

Field of the invention

[0001] The invention relates to a force sensor element, a force sensor arrangement with a corresponding force sensor element, and a method for producing a corresponding force sensor element. State of the art

[0002] A force can be measured by detecting and evaluating the elastic deformation of a known component under the force. For example, a flexural spring with a known geometry and known material properties can be elastically deformed by the force. The deformation of the flexural spring can be detected, for example, at a free end of the flexural spring using a position sensor.

[0003] Alternatively, the deformation can be detected using at least one strain gauge glued to the bending spring. The strain gauge consists of a wire arranged in a meandering shape between two foils. The wire changes its electrical resistance depending on its elongation. Because it is glued to the bending spring, the wire is stretched or compressed when the bending spring deforms. However, the wire also changes its electrical resistance depending on a change in temperature. The changes in resistance due to the elongation and the change in temperature overlap. To compensate for the change in resistance due to the temperature, at least one additional strain gauge without elongation can be exposed to the same temperature change as the at least one stretched strain gauge.In particular, the changes in the electrical resistance of four such strain gauges can be evaluated using a Wheatstone bridge circuit. Disclosure of the invention

[0004] Against this background, the approach presented here provides a force sensor element, a force sensor arrangement with a corresponding force sensor element, and a method for producing a corresponding force sensor element according to the independent claims. Advantageous further developments and improvements of the approach presented here emerge from the description and are described in the dependent claims. Advantages of the invention

[0005] In the approach presented here, the wire of a strain gauge is replaced by a flat resistance element machined from an electrically conductive metal sheet. The resistance element consists of at least one continuous conductor track with a material thickness equal to the thickness of the metal sheet, which, in an application-specifically arranged and / or aligned pattern, fills an application-specifically designed area of the metal sheet, essentially tightly packed, particularly with minimal gaps. This area can be referred to as the resistance area.

[0006] The resistance element is embedded in an electrically insulating bedding and electrically contacted via electrical contacts in the metal sheet. The bedding is deformed by a force acting on it, stretching or compressing the resistance element embedded in it. The bedding essentially acts like a spiral spring. Stretching reduces the electrical conductivity of the resistance element, thus increasing its electrical resistance. Compression increases the electrical conductivity, and the electrical resistance decreases.

[0007] Since this resistance element also changes its electrical resistance not only depending on its expansion but also depending on its temperature change, a bridge circuit consisting of four approximately equally tempered resistance elements is advantageous for temperature compensation. Here, the four resistance elements are combined in the same metal sheet. The resistance elements are integrally connected to one another via electrically conductive connecting areas of the metal sheet. The connecting areas also form electrical connections for contacting the resistance elements as part of a bridge circuit. The resulting component can be referred to as an expansion plate. Except for the connections, the expansion plate is completely embedded in the bedding to form a force sensor element.

[0008] The bedding is designed so that at least one of the resistance elements is stretched, and at least one of the resistance elements is stretched as little as possible or not at all. Depending on the application, between 1 / 4 and 3 / 4 of the resistance elements of the force sensor element can be stretched, and the remaining 3 / 4 to 1 / 4 of the resistance elements of the force sensor element can be used for temperature compensation.

[0009] The approach presented here allows the four resistance elements to be manufactured very cost-effectively from the same piece of sheet metal in a single step. The shape of the resistance elements can be varied almost infinitely to configure the force sensor element for a wide variety of applications. Furthermore, the shape of the bedding can be varied depending on the application in order to achieve a desired deformation direction of the bedding and of the at least one stretchable resistance element or resistance region when a force to be measured is applied to the bedding.

[0010] According to a first aspect of the present invention, a method for producing a force sensor element is proposed, wherein an expansion plate with four resistance regions that are electrically conductively connected to one another in a ring-shaped manner and four taps that are each arranged between two of the resistance regions is formed from a piece of electrically conductive metal sheet, wherein the expansion plate is embedded in a bedding of an electrically insulating material so that the taps can be electrically contacted to form a bridge circuit.

[0011] According to a second aspect of the present invention, a force sensor element is proposed, wherein the force sensor element has an expansion plate with four resistance regions that are connected to one another in an annular manner in an electrically conductive manner and four taps arranged between two of the resistance regions, as well as a bedding made of an electrically insulating material, wherein the expansion plate is embedded in the bedding so that the taps can be electrically contacted to form a bridge circuit.

[0012] According to a third aspect of the present invention, a force sensor arrangement is proposed, wherein a force sensor element according to the second aspect is arranged between two pressure surfaces and the four taps of the expansion plate are electrically conductively contacted by an evaluation device to form a bridge circuit.

[0013] Ideas for embodiments of the present invention can be considered, among other things, to be based on the thoughts and findings described below.

[0014] A force sensor element can be a force-sensitive part of a force sensor assembly. The force sensor element can be a passive component that is supplied with electrical voltage by an electrical circuit and from which an electrical quantity is tapped. A change in the electrical quantity can result in response to a change in the force applied to the force sensor element. The electrical quantity can change proportionally to the force applied.

[0015] A resistance region can be a resistance element arranged in a main extension plane of a metal sheet and made of at least one conductor machined from the metal sheet. The conductor can electrically connect one end of the resistance element to an opposite end of the resistance element in an approximately freely selectable path. Sections of the conductor can run essentially parallel to one another, for example, in the form of windings. Within the resistance region, the conductor can be separated from itself or other electrically conductive regions of the metal sheet by an insulating distance. A gap can therefore be arranged between the conductor and adjacent electrically conductive parts of the metal sheet.

[0016] The resistance element can also have two or more electrical conductors of equal length. The conductors can then run parallel to each other over a large portion of their length. Alternatively, the conductors can each run within their own sub-regions of the resistance region. In this case, sections of the conductor can run essentially parallel to each other within the sub-regions, for example, in the form of windings. At least one conductor can be aligned in a preferred direction over a large portion of its length. Likewise, the conductor can run approximately randomly within the resistance region or within its sub-region, without a preferred direction.

[0017] The four resistance zones of an expansion plate can be arranged in a common plane. The expansion plate can also be bent so that at least one of the resistance zones is aligned in a different plane. The expansion plate can also be plastically deformed in multiple dimensions.

[0018] The resistance ranges can be freely designed. For example, all resistance ranges can be the same size. Likewise, all resistance ranges can be different sizes. Likewise, two resistance ranges can be the same size. Likewise, three resistance ranges can be the same size, while one of the resistance ranges can have a different size.

[0019] The resistance regions can be arranged evenly distributed across the expansion plate. The resistance regions can also be arranged irregularly across the expansion plate. The conductors of the resistance regions can be aligned essentially in the same preferred direction. Likewise, the conductors of the different resistance regions can be aligned in different preferred directions. At least one conductor of one of the resistance regions can be aligned in a preferred direction, while at least one other conductor of another resistance region can be arranged randomly.

[0020] A bedding can be made of a plastic or ceramic material, for example. The bedding can be formed into a desired shape around the expansion plate. The bedding can exhibit a defined elasticity. The bedding can be elastically deformed by the application of force. After the application of force ceases, the bedding can return to its original shape.

[0021] An evaluation device can, in particular, comprise the remaining components of a Wheatstone bridge circuit. In particular, the evaluation device comprises a voltage source and a voltmeter. The voltage source is connected to two of the taps in such a way that two of the resistance regions, also commonly called bridge arms, form a voltage divider, i.e., are connected in series. The two voltage dividers are thus connected in parallel. The voltmeter is connected to the two remaining taps, i.e., between the two voltage dividers. Thus, a change in the electrical resistance in at least one bridge arm directly results in a change in the measured voltage.

[0022] The expansion plate can be formed using a light-assisted forming process. A light-assisted forming process can be a direct forming process, removing material through direct irradiation with electromagnetic waves, such as laser cutting. The light-assisted forming process can also be an indirect forming process, in which a particularly temporary preform is produced using electromagnetic waves, such as exposing a protective light-sensitive lacquer layer. Material removal can then occur in unexposed and therefore unprotected areas of the metal sheet, for example, by etching using an aggressive chemical, such as an acid. This process is generally referred to as photochemical metalworking.A light-assisted forming process can create very precise, small structural widths, down to the thickness of the metal sheet. The light-assisted forming process can be carried out fully automated.

[0023] The bedding can be produced using a primary forming process. The bedding can be formed in the cavity of a primary forming tool. For example, the bedding can be molded into its desired shape by casting, sintering, pressing, injection molding, or vulcanizing. The bedding material can be introduced into the mold cavity, particularly in a liquid or powdered state, and enclose the expansion plate. Within the mold cavity, the material can transition to a solid state, for example, by cooling, sticking together, or chemically reacting. Primary forming allows for virtually unlimited freedom in the shaping of the bedding.

[0024] The bedding can be made of an elastic material. The bedding can be made of an elastomer. In particular, the elastic modulus of the material used for the bedding can be lower than that of the material forming the expansion plate. This allows the bedding to stretch elastically when a force is applied, particularly transversely to a force direction, and the expansion plate can stretch along with it.

[0025] The bedding can have at least one depression on at least one surface oriented substantially parallel to a main direction of extension of the expansion plate. This allows at least one cavity to be formed between at least one of the pressure surfaces and the bedding. The bedding can rest against the pressure surface all the way around the cavity. The at least one depression can alternatively or additionally also be formed in the pressure surface(s). The cavity can, for example, be filled with gas. The gas can be air, for example. The bedding can be deformed into the cavity by the action of force. The depression can thereby decrease or disappear. The cavity or depression can make the bedding locally less rigid. At least one of the resistance regions can be arranged in the region of the depression or cavity.At least one other resistance region can be arranged laterally offset from the recess or cavity. This resistance region can be deformed only slightly or not at all when the force is applied, thus serving to compensate for temperature.

[0026] The cavity can be connected to the environment via a pressure equalization channel. The pressure equalization channel allows gas to escape from the cavity when the cavity is reduced under the action of force. This prevents counterpressure from building up in the cavity, which could impede the deformation of the bedding. The pressure equalization channel can lead through the pressure surface or through the bedding.

[0027] At least one of the pressure surfaces can have an edge that at least substantially laterally encloses the force sensor element. This edge can prevent lateral displacement of the force sensor element. The edge can be spaced from the bedding in the unforced state. The bedding can then deform laterally up to the edge when a force is applied. Upon contact with the edge, the lateral deformation can be limited.

[0028] Alternatively, the edge can rest against the side surfaces of the bedding when the force sensor assembly is in a force-free state. This edge can then prevent the bedding from deflecting sideways during the application of force. Especially in combination with a cavity, this allows the deformation of the force sensor element to be controlled.

[0029] It should be noted that some of the possible features and advantages of the invention are described herein with reference to different embodiments. One skilled in the art will recognize that the features of the force sensor element, the force sensor assembly, and the method can be combined, adapted, or interchanged as appropriate to achieve further embodiments of the invention. Short description of the drawings

[0030] Embodiments of the invention are described below with reference to the accompanying drawings, wherein neither the drawings nor the description are to be construed as limiting the invention. Fig. 1 shows a representation of a force sensor arrangement according to an embodiment; and Fig. 2 shows representations of expansion plates according to embodiments.

[0031] The figures are merely schematic and not to scale. Like reference numerals denote like or equivalent features. Embodiments of the invention

[0032] Fig. Figure 1 shows a representation of a force sensor assembly 100 according to one exemplary embodiment. The force sensor assembly 100 comprises a force sensor element 102 and an evaluation device 104. The force sensor element 102 is arranged between two pressure surfaces 106. The force sensor element 102 is loaded with a force F via the pressure surfaces 106.

[0033] The force sensor element 102 consists of an expansion plate 108 and a bedding 110 in which the expansion plate 108 is embedded.

[0034] The expansion plate 108 is a piece of contoured sheet metal. The expansion plate 108 is contoured to have four resistance regions 112 and four taps 114. The resistance regions 112 are electrically connected to one another. Each end of each resistance region 112 is connected to the beginning of the next resistance region 112. The end of the last resistance region 112 is again connected to the beginning of the first resistance region 112, resulting in a closed, ring-shaped structure. The taps 114 are each arranged between a beginning and an end.

[0035] The evaluation device 104 is connected to the taps 114 via four lines 116. Two of the taps 114 are connected to a voltage source 118 of the evaluation device 104. The other two taps 114 are connected to a voltmeter 120 of the evaluation device 104. Between the poles of the voltage source 118, both voltage dividers, each consisting of two series-connected resistor regions 112, are connected in parallel to form a full bridge. The voltmeter 120 connects the voltage dividers and taps a voltage between the resistor regions 112.

[0036] When force F is applied to force sensor element 102 via pressure surfaces 106, bedding 110 deforms, and this deformation is transferred to expansion plate 108. The deformation of expansion plate 108 changes the electrical resistance of at least one of resistance regions 112. The change in resistance leads to a change in the measured voltage.

[0037] In one embodiment, the bedding 110 has a depression 122 in the area of one of the resistance regions 112. The depression 122 creates a cavity 124 between one of the pressure surfaces 106 and the bedding. When the force sensor element 102 is compressed by the force F, the bedding 110 can deform into the cavity 124. If the force F is large enough, the cavity 124 disappears and the bedding 110 rests against the pressure surface 106. The cavity 124 deforms the resistance region 112 above it more than at least one of the other resistance regions 112. The resistance region 112 located above the cavity 124 is thus force-sensitive, while the resistance regions 112 located next to the cavity 124 are essentially force-insensitive and serve for temperature compensation.

[0038] The bedding 110 and / or the pressure surface 106 may also have a plurality of depressions 122. Likewise, the cavity 124 may be so large that more than one of the resistance regions 112 lies within the sphere of influence of the cavity 124.

[0039] In one embodiment, one of the pressure surfaces 106 has an edge 126. The edge encloses side surfaces of the force sensor element 102. The edge 126 prevents lateral deformation of the bedding 110 and protects the expansion plate 108 from damage caused by excessive deformation.

[0040] Fig. Figure 2 shows representations of expansion plates 108 according to exemplary embodiments. The expansion plates 108 can be used in force sensor elements as in Fig.1. The expansion plates 108 have different basic shapes. The expansion plates can be designed for specific applications. All expansion plates 108 have four resistance regions 112 and four taps 114. The resistance regions 112 each have a connection region 200 at opposite ends of their conductors. The connection regions 200 have a larger cross-section than the conductors of the resistance regions 112. The connection regions 200 are strips made from the same piece of sheet metal from which the resistance regions 112 were machined. A connection region 200 is always arranged between two resistance regions 112 and is electrically connected to both resistance regions 112. The taps 114 are arranged at the connection regions 200. The taps 114 are designed such that they protrude from the bedding (not shown).The taps 114 can be arranged in a main extension plane of the metal sheet or be bent out of the main extension plane. For example, the taps can be bent upward approximately perpendicular to the main extension plane. In this case, the taps can be contacted, for example, through recesses in one or both pressure surfaces 106.

[0041] The resistance regions 112 of the various embodiments have different shapes and sizes. For example, the resistance regions 112 can be round, polygonal, or arc-shaped.

[0042] In three of the illustrated embodiments, the expansion plate 108 has a round basic shape, a round resistance region 112 is arranged centrally in the expansion plate 108, and three arcuate resistance regions 112 are arranged around the round resistance region 112. In the three embodiments, the resistance regions 112 have different areas.

[0043] In two of the illustrated embodiments, the expansion plates 108 have a rectangular basic shape, a polygonal resistance region 112 is arranged essentially centrally in the expansion plate 108, and three polygonal resistance regions 112 are arranged around the central resistance region 112. The resistance regions 112 are of different sizes and shapes. The taps 114 also have different lengths in these embodiments.

[0044] In each case, a different number of the resistance regions 112 are provided as force-sensitive. Accordingly, a different number of the resistance regions 112 are provided as force-insensitive and for temperature compensation.

[0045] In the following, possible embodiments of the invention are summarized again or presented with slightly different wording.

[0046] An integrated full-bridge strain gauge (IVBDMS) is presented.

[0047] The approach presented here is based on the measuring principle of strain gauges (SGs). The measuring principle of converting forces into electrical voltage using strain gauges has been an established method for decades. The physical basis of the strain gauge method is the change in electrical resistance in the strain gauge due to external influences such as temperature and deformation. Force measurements utilize the deformation of the strain gauge. These strain gauges typically consist of a fine wire meandering inside a foil. This foil strain gauge is glued to a component that deforms under force to measure force.

[0048] When the strain gauge is stretched due to deformation, the wire length in the strain gauge changes, and so does the electrical resistance. The latter is part of the measuring chain and generates the measurement signal. The key difficulty here is compensating for the influence of temperature on the specific electrical resistance of the strain gauge wire material. This is, however, quite easy to achieve if four individual strain gauges are used as a full bridge and positioned in the same temperature environment. Whether all four strain gauges experience strain or only a small amount is only relevant for signal interpretation. However, if all four strain gauges experience the same strain and temperature, no signal is produced. At least one strain gauge must experience a different strain or exhibit different strain behavior.

[0049] One manufacturing process used here, in particular, is metal etching. Metal sheets with very fine geometries, produced by etching, are already widely used in mass-produced products. This technique allows structures to be produced in the range of the metal sheet thickness, even in the range of 50 µm, while maintaining very tight tolerances.

[0050] Another manufacturing process used here is composite processing. Overmolding metal components with plastic has been established for years in a variety of high-volume products. However, sintering or vulcanizing non-metallic materials around a metal component has also been used in high-volume production for several years.

[0051] This article presents a cost-effective force measurement system suitable for large-scale production. Many products currently on the market require the functionality of a force measurement system. Current standard components for force measurement, which are typically based on piezoelectric, electrocapacitive, or electroresistive conversion principles, are very expensive to manufacture. Therefore, the force measurement function is often implemented indirectly, with compromises in accuracy, resolution, and measuring range being accepted. The most common principle is to use the electrical power of the drive as a force measure. Examples of such products include anti-pinch protection for power windows in cars or overload protection for lifting devices. Direct force measurement with lower manufacturing costs would improve functionality and thus provide a significant advantage.

[0052] The integrated full-bridge strain gauge "IVBDMS" presented here, provided a suitable electrical amplifier and a transducer are available, enables the axial force between two connecting bodies to be determined. This makes the IVBDMS a force measurement system. Since the measuring range and resolution of the IVBDMS are very easy to dimension, while the manufacturing costs remain low, it has a wide range of applications.

[0053] The IVBDMS consists of an expansion plate and a bedding. The expansion plate, located in the bedding, can be placed in a shell and compressed by a stamp.

[0054] The expansion plate can be manufactured by etching sheet metal. The bedding can be produced by non-metal injection molding or non-metal sintering. The expansion plate embedded in the bedding can be referred to as a composite expansion plate. The shell and die can be manufactured by machining or forming processes. The approach presented here enables low component costs, cost-effective assembly suitable for large-scale production, and unproblematic scalability.

[0055] An expansion plate etched from a metal sheet, with its contour, represents a full strain gauge bridge in a component. If required from a design perspective, the connection contacts to the measuring amplifier can be raised from the plane of the expansion plate by bending. The individual resistors R1, R2, R3, and R4 are electrical conductors used as expansion elements and are defined by the geometry of the expansion plate. Any orientation of the expansion elements, such as primarily radial, primarily circumferential, or any freeform, can be used. The positioning and design of the outer shape of each of the four resistors is also highly variable. Only the correct electrical contacting of the resistors is required.

[0056] The expansion plate is embedded in an electrically non-conductive material, with the connection contacts, possibly previously bent upwards, protruding from this bedding. The elasticity of the bedding is deliberately chosen to scale the deformation resulting from the axial force to be determined. Elastomers, plastics, or even ceramics can be used as the bedding material. Depending on the material, the expansion plate can be embedded in the bedding by injection molding, sintering, or vulcanization.

[0057] The composite component consisting of the expansion plate and bedding can be arranged in a shell. This shell is significantly stiffer than the bedding itself. A cavity can be formed at the bottom of the bedding. This prevents the bedding from resting completely on the shell floor, for example. The cavity can be ventilated using suitable design features, such as holes and grooves. However, this ventilation is only necessary if a gas spring has an excessive influence on the measurement result. This will primarily only be the case when measuring low forces. The cavity can be created by the shape of the bedding and / or the shell.

[0058] A punch can be mounted on top of the bedding. This punch can be secured against rotation relative to the bedding by a tongue-and-groove connection. The punch is highly rigid. The punch can be guided in the shell with a slight clearance fit. The punch can also have feedthroughs for the connecting contacts. If structurally possible, the punch can also be part of an upper attachment body. The shell can also be part of a lower attachment body.

[0059] An axial force "F" emanating from the upper attachment body or punch and directed through the bedding into the lower attachment body or shell deforms the bedding and the expansion plate located therein. In order to amplify this deformation in a defined manner or to allow it to act only locally, a cavity can be provided between the bedding and the lower attachment body or shell and / or the bedding and the upper attachment body or punch. The aim is to enlarge the bending line BL of the expansion plate without leaving the linear elastic range of the expansion plate material. To ensure that the linear elastic range is not left even by extremely high axial forces, the stiffness of the bedding and the unloaded cavity geometry are coordinated in such a way that above a certain axial force level the cavity is no longer present - the initially existing gap S then no longer exists.In this state, the measurement resolution of the IVBDMS is significantly reduced, but the IVBDMS is also protected against overload.

[0060] By designing and positioning cavities, it is possible to make only a specific number of the four resistors R1, R2, R3, and R4 sensitive to the force-induced strain. This allows the resolution of the IVBDMS to be increased without excessive degradation of temperature compensation.

[0061] The external shape of the shell and stamp can be designed in a variety of ways, depending on the force connection and guidance as well as the laying of the electrical cables.

[0062] The dimensions of an IVBDMS are limited by the metal etching manufacturing process, but range from approximately 1 mm to 1 m. This allows for dimensioning for a very wide range of forces while maintaining a consistently high resolution. An IVBDMS is therefore feasible for many applications.

[0063] The expansion plate, etched from sheet metal, can have subsequently bent contacts. The contacts can be bent open before the expansion plate is embedded in the bedding. The expansion plate is integrated into a full-bridge circuit.

[0064] The outer shape of the respective resistors R1, R2, R3, and R4 is almost arbitrary. Only the electrical contact at the corresponding points is required. Furthermore, a hollow space can ensure a locally less load-bearing bedding. This allows only certain resistors to be stretched as a result of an external force F. The remaining resistors thus serve only for temperature compensation.

[0065] Finally, it should be noted that terms such as "comprising," "having," etc., do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality. Reference signs in the claims are not to be considered limiting.

Claims

[1] Method for producing a force sensor element (102), wherein an expansion plate (108) with four resistance regions (112) connected to one another in an electrically conductive manner in a ring and four taps (114) arranged between two of the resistance regions (112) is formed from a piece of electrically conductive metal sheet, wherein the expansion plate (108) is embedded in a bedding (110) made of an electrically insulating material, so that the taps (114) can be electrically contacted to form a bridge circuit. [2] The method of claim 1, wherein the expansion plate (108) is formed by a light-assisted forming process. [3] Method according to one of the preceding claims, in which the bedding (110) is produced by a primary forming process. [4] Force sensor element (102), wherein the force sensor element (102) has an expansion plate (108) with four resistance regions (112) connected to one another in an electrically conductive manner in a ring shape and four taps (114) arranged between two of the resistance regions (112), as well as a bedding (110) made of an electrically insulating material, wherein the expansion plate (108) is embedded in the bedding (110) so that the taps (114) can be electrically contacted to form a bridge circuit. [5] Force sensor element (102) according to claim 4, wherein the bedding (100) consists of an elastic material. [6] Force sensor element (102) according to one of the preceding claims, wherein the bedding (110) has at least one recess 122 on at least one surface aligned substantially parallel to a main extension direction of the expansion plate (108). [7] Force sensor arrangement (100), wherein a force sensor element (102) according to one of claims 4 to 6 is arranged between two pressure surfaces (106) and the four taps (114) of the expansion plate (108) are electrically conductively contacted by an evaluation device (104) to form a bridge circuit. [8] Force sensor arrangement (100) according to claim 7, wherein at least one cavity (124) is formed between at least one of the pressure surfaces (106) and the bedding (110), wherein the bedding (110) bears against the pressure surface (106) circumferentially around the cavity (124). [9] Force sensor arrangement (100) according to claim 8, wherein the cavity (124) has a connection to an environment via a pressure equalization channel. [10] Force sensor arrangement (100) according to one of claims 7 to 9, wherein at least one of the pressure surfaces (106) has an edge (126) at least substantially laterally enclosing the force sensor element (102). [11] Force sensor arrangement (100) according to claim 10, wherein the edge (126) rests against side surfaces of the bedding (110) in a force-free state of the force sensor arrangement (100).

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