Inductive measuring arrangement and pedal arrangement for a vehicle

Abstract

The invention relates to an inductive measuring arrangement (10) with at least one evaluation and control unit (11), a circuit carrier (7) on which at least one transmitting structure (12) and at least one receiving structure (16) are arranged, and at least one electrically conductive coupling element (14), wherein the at least one evaluation and control unit (11) is designed to couple a periodic electrical alternating signal into the at least one transmitting structure (12) and to receive a measurement signal induced into the at least one receiving structure (16) via the at least one electrically conductive coupling element (14) based on an eddy current principle, which measurement signal represents a current distance (A) or a change in the distance (A) between the circuit carrier (7) and the at least one electrically conductive coupling element (14), and to generate and output an output signal based on the measurement signal,and a pedal arrangement (1) with at least one such inductive measuring arrangement (10).,

Description

[0001] The invention relates to an inductive measuring arrangement. The present invention also relates to a pedal arrangement for a vehicle, comprising such an inductive measuring arrangement.

[0002] Pedal assemblies are known from the prior art, which are used, for example, to implement brake pedals or accelerator pedals. Such a pedal assembly for implementing a brake pedal is designed, for example, as a hydraulic system with at least one hydraulic cylinder. In order to provide sufficient fluid volumes to actuate the at least one hydraulic cylinder, the corresponding brake pedal has a long actuation travel of approximately 70 mm. The brake pedal is usually actuated via a lever that is significantly longer than the height of the pedal surface. This means that it is largely irrelevant where on the pedal surface the foot rests for actuation.

[0003] Electrification of the braking system (brake-by-wire) makes it possible to reduce actuation travel through the use of force sensors while still enabling precise operation. The goal is to use a force-sensitive pedal plate as a replacement for the traditional brake pedal with a short actuation distance of less than 2 mm, which the driver no longer perceives as "pedal travel." The main challenges for the force sensor are contamination resistance, a flat design, surface load measurement and detection of uneven loading on the pedal plate, EMC robustness (particularly relevant for electric vehicles), functional safety, and competitive manufacturing costs.

[0004] Force measurement can also be achieved by combining a linear spring element with a distance measurement. In industrial settings, distance-measuring inductive sensors with a coil are widely used. The basic principle of such inductive sensors is the change in inductance or its quality factor due to a change in the position of the sensor relative to an electrically conductive and / or ferromagnetic part. The coil, usually as part of an oscillating circuit, emits a magnetic field that induces eddy currents in a passing electrically conductive material, which is why this sensor design is also called an eddy current sensor. The amplitude and frequency of the oscillating circuit change. Using a Schmitt trigger, the output can be switched upon a certain change, or the amplitude can be converted into a distance. The coil is typically wound around a ferrite core.This design ensures that such sensors are large in the axial sensing direction, while the dimensions orthogonal to the sensing direction are small. A particular disadvantage for use in a pedal is the space required in the axial direction. Another disadvantage is the complex construction with a wound coil. This complex design makes these sensors expensive. Most inductive distance sensors operate as switches, meaning their output can only assume two states. This resolution is too low for application in a pedal.

[0005] DE 198 11 268 A1 discloses a foot-operated control device for influencing drive or deceleration means in a motor vehicle, comprising a signal generator having supply lines that generate a control signal dependent on the actuation travel. The signal generator has an elastic and conductive body provided with a first electrical contact area that extends over a first surface of the body and is conductively connected, on the one hand, to the body and, on the other hand, to a first supply line. A second electrical contact area extends over a second surface of the body opposite the first surface and is conductively connected, on the one hand, to the body and, on the other hand, to a second supply line.The electrical resistance of the body between the two contact areas depends on the distance between the two contact areas, and a measuring transducer is connected downstream of the signal generator, the inputs of which are connected to the first and second contact areas via the supply lines, and at the output of which the control signal can be taken, which forms a measure of the electrical resistance. Disclosure of the invention

[0006] The inductive measuring arrangement with the features of independent patent claim 1 has the advantage that the eddy current principle used makes it possible to provide a safe and cost-effective inductive measuring arrangement which, despite a “small” axial actuation travel of less than two millimeters (2mm), can nevertheless generate a proportional signal which is suitable, for example, for a brake pedal to activate a braking function or for an accelerator pedal to activate an acceleration function.

[0007] Embodiments of the present invention provide an inductive measuring arrangement with at least one evaluation and control unit, a circuit carrier on which at least one transmitting structure and at least one receiving structure are arranged, and at least one electrically conductive coupling element. The at least one evaluation and control unit is designed to couple a periodic electrical alternating signal into the at least one transmitting structure and to receive a measurement signal induced into the at least one receiving structure via the at least one electrically conductive coupling element based on an eddy current principle, which measurement signal represents a current distance or a change in the distance between the circuit carrier and the at least one electrically conductive coupling element, and to generate and output an output signal based on the measurement signal.

[0008] In addition, a pedal arrangement for a vehicle is proposed, comprising at least one movably mounted pedal plate which can be actuated against a force of at least one spring element over a predetermined axial actuation path, and at least one such inductive measuring arrangement which is designed to detect the actuation of the pedal plate and the corresponding actuation path.

[0009] Embodiments of the inductive measuring arrangement utilize the eddy current principle, in which electromagnetic fields are coupled from the at least one transmitting structure to one or more receiving structures via the at least one electrically conductive coupling element. The position, in particular the distance, of the at least one electrically conductive coupling element in relation to the at least one transmitting structure and the at least one receiving structure determines the strength of the inductive coupling. This coupling is measurable via an induced voltage in the at least one receiving structure and allows the determination of the distance between the at least one electrically conductive coupling element and the circuit carrier.

[0010] Since an axial actuation travel of approximately one millimeter is sufficient to change the output signal or measurement signal by a factor of two, for example, using the eddy current principle, a distance to be detected or a change in the distance to be detected between the circuit carrier and the at least one electrically conductive coupling element of the inductive measuring arrangement or an axial actuation travel of the pedal arrangement to be detected can preferably be specified in the range of 1 mm to 5 mm. This allows a flat design of the inductive measuring arrangement and the corresponding pedal arrangement in the axial sensing direction. Through suitable design, a linear relationship between an actuation force and the output signal of the inductive measuring arrangement can be achieved. In addition, embodiments of the inductive measuring arrangement enable a continuous output signal with high resolution and accuracy, instead of a binary "switch output".With the otherwise conventional force sensors using strain gauges, in addition to the disadvantageous point measurement, the design freedom is very limited because the deformation body and measuring strip must be placed in the same location. Designs of the inductive measuring arrangement are capable of measuring actuation forces across a large area, including possible tilting. By separating the deformation body and measuring points, designs of the pedal arrangements enable very high degrees of redundancy independent of the deformation body. This allows for very high functional safety. With appropriate design, inductive distance measurement using designs of the inductive measuring arrangement is intrinsically robust to interference fields. Furthermore, designs of the inductive measuring arrangement enable a simple construction of the pedal arrangement for a vehicle using inexpensive components. Furthermore, no wound coils are required.The inductive measuring arrangement can preferably be implemented on a standard circuit board. Furthermore, an existing circuit board provides additional space for heterogeneous redundancies for distance measurement, for example, based on optical or magnetic means.

[0011] In this case, the evaluation and control unit can be understood to be an electrical circuit that processes or evaluates detected sensor signals. The evaluation and control unit can have at least one interface, which can be implemented in hardware and / or software. In a hardware implementation, the interfaces can, for example, be part of a so-called system ASIC module (ASIC: Application-Specific Integrated Circuit), which contains a wide variety of functions of the evaluation and control unit. However, it is also possible for the interfaces to be separate integrated circuits or to consist at least partially of discrete components. In a software implementation, the interfaces can be software modules that are present, for example, on a microcontroller alongside other software modules.Also advantageous is a computer program product with program code stored on a machine-readable medium such as a semiconductor memory, a hard disk memory or an optical memory and used to carry out the evaluation when the program is executed by the evaluation and control unit.

[0012] The measures and further developments listed in the dependent claims enable advantageous improvements to the inductive measuring arrangement specified in independent patent claim 1.

[0013] It is particularly advantageous that the at least one electrically conductive coupling element or the circuit carrier can be coupled to a movable body which can be moved against a force of at least one spring element. In this case, the at least one evaluation and control unit can be further designed to generate and output a further output signal based on the measurement signal and on predetermined properties of the at least one spring element, which represents a currently acting actuating force on the movable body. The output signals can, for example, be generated and output by a common evaluation and control unit or by two separate evaluation and control units. The two separate evaluation and control units can thus be arranged on the circuit carrier of the inductive measuring arrangement. Alternatively, the common evaluation and control unit ora first evaluation and control unit can be arranged on the circuit carrier of the inductive measuring arrangement. Furthermore, the common evaluation and control unit or a second evaluation and control unit can be arranged in a higher-level control unit which is electrically connected to the inductive measuring arrangement. The use of the eddy current principle has several technical advantages for the implementation of a force-measuring inductive measuring arrangement with a negligible axial actuation travel. The small axial actuation travel of the movable body or the small change in distance between the at least one electrically conductive coupling element and the circuit carrier in combination with the known properties of the at least one spring element can be used to determine the applied actuation force or pedal force.A desired force-displacement characteristic curve for the actuation force can be set using the properties of the at least one spring element. The spring properties can preferably be dimensioned such that the relationship between the force exerted on the at least one spring element and the change in distance between the at least one electrically conductive coupling element and the circuit carrier is linear. Of course, nonlinear behavior can also be applied to positively influence the feel when actuating the movable body or the pedal plate. With a known force-displacement characteristic curve, the conversion of the change in distance into actuation force is still possible.

[0014] In an advantageous embodiment of the inductive measuring arrangement, the movable body can be, for example, a pedal plate of a pedal arrangement for a vehicle. In embodiments of the pedal arrangement, the separation of the deformation elements and sensor surfaces can be easily achieved due to the separation of the at least one spring element from the at least one transmitting structure and the at least one receiving structure on the common circuit carrier. Therefore, simple adaptation of force measuring ranges is possible without changing the at least one transmitting structure and the at least one receiving structure on the common circuit carrier. In addition, good EMC behavior can be implemented through a fixed operating frequency and / or a differential measuring principle. The at least one spring element can be designed, for example, as a disc spring, a short helical spring, or even as an elastomer element.The at least one spring element can also be composed of several distributed springs. In addition, the at least one spring element can be designed as a tensile bead that connects the pedal plate to a frame. In this case, the at least one electrically conductive coupling element or the circuit carrier can be coupled to the pedal plate and moved with it when the pedal plate is actuated. This means that the at least one electrically conductive coupling element can be coupled to the pedal plate and the circuit carrier can be stationary. As a result, when the pedal plate is actuated, the at least one electrically conductive coupling element can be moved with it, while the circuit carrier is not moved. Alternatively, the circuit carrier can be coupled to the pedal plate and the at least one electrically conductive coupling element can be stationary.When the pedal plate is actuated, the circuit carrier can then be moved along with it, while the at least one electrically conductive coupling element is not moved. In this case, the coupling or connection between the pedal plate and the at least one electrically conductive coupling element or the circuit carrier can be designed such that the current distance between the circuit carrier and the at least one electrically conductive coupling element decreases when the pedal plate is actuated. Alternatively, the coupling or connection between the pedal plate and the at least one electrically conductive coupling element or the circuit carrier can be designed such that the current distance between the circuit carrier and the at least one electrically conductive coupling element increases when the pedal plate is actuated.This alternative design can be used particularly for applications that require particularly high accuracy in the lower force range.

[0015] In a further advantageous embodiment of the inductive measuring arrangement, the at least one transmitting structure can comprise at least one planar transmitting coil, and the at least one receiving structure can comprise at least one planar receiving coil. With a planar coil, the winding is not made of wire, such as copper wire, but rather of etched conductor tracks of the circuit carrier. This enables a simple and cost-effective implementation of the at least one transmitting structure and the at least one receiving structure in the circuit carrier.

[0016] In a further advantageous embodiment of the inductive measuring arrangement, the circuit carrier can be designed as a multilayer printed circuit board. This enables simple and cost-effective production of the circuit carrier. Alternatively, the circuit carrier can be designed as overmolded busbars or as an injection-molded circuit carrier (MID: Molded Interconnect Devices).

[0017] In a further advantageous embodiment of the inductive measuring arrangement, the at least one planar transmitting coil and / or the at least one planar receiving coil can be arranged in multiple layers of the circuit board. The sections of the at least one planar transmitting coil and / or the at least one planar receiving coil arranged in different layers can be electrically connected to one another via vias and connected in series. Here, "planar" is to be understood as meaning that the spatial extent in the "planar plane" is significantly larger than the spatial extent across the layers of the circuit board.

[0018] In a further advantageous embodiment of the inductive measuring arrangement, the circuit carrier can be arranged between two electrically conductive coupling elements. In this case, a current first distance between a first electrically conductive coupling element and the circuit carrier can decrease during a movement of the movable body based on an acting actuating force, and a current second distance between a second electrically conductive coupling element and the circuit carrier can increase during the movement of the movable body based on the acting actuating force. By appropriately arranging the two electrically conductive coupling elements relative to the circuit carrier, a relationship between the voltage induced in the at least one receiving structure and the distance between the at least one electrically conductive coupling element and the circuit carrier can be largely linearized.The use of two electrically conductive coupling elements can provide improved linearization than just one electrically conductive coupling element.

[0019] In a further advantageous embodiment of the inductive measuring arrangement, the at least one receiving structure can comprise at least one coil pair comprising two adjacently arranged planar receiving coils with opposing windings. The opposing windings of the two receiving coils allow external interference fields to be effectively suppressed.

[0020] In a further advantageous embodiment of the inductive measuring arrangement, the planar receiving coils of a coil pair can have, for example, a geometric polygon shape, preferably a geometric rectangular shape or a geometric triangular shape, or a geometric circular shape or a geometric semicircular shape or a geometric elliptical shape or another suitable geometric shape.

[0021] In a further advantageous embodiment of the inductive measuring arrangement, the at least one planar transmitting coil of a corresponding transmitting structure can geometrically enclose the coil pair of the at least one receiving structure. As a result, the at least one coil pair is arranged entirely within an area spanned by the at least one planar transmitting coil.

[0022] In a further advantageous embodiment of the inductive measuring arrangement, the at least one electrically conductive coupling element can at least partially cover an area spanned by the at least one coil pair and an area spanned by the at least one planar transmitting coil. Preferably, the at least one electrically conductive coupling element can be based on the same geometric shape as the at least one receiving coil. In addition, the at least one electrically conductive coupling element can, for example, cover half of the area spanned by the two receiving coils of the at least one coil pair. By covering half of the area spanned by the receiving coils of the at least one coil pair, it can be achieved that a signal can be generated by forming the difference in the two receiving coils, while external interference influences that affect both receiving coils equally are suppressed.Of course, a different degree of coverage can also be implemented, such as an overlap of one quarter or one third of the receiving coils of the at least one coil pair. Depending on the distance to the circuit carrier, the at least one electrically conductive coupling element can transfer energy from the at least one transmitter coil to the at least one receiving coil, which can be measured as voltage or current at the at least one receiving coil. Half coverage can also be achieved by the at least one electrically conductive coupling element having a profile structure that has different heights above the two receiving coils. The at least one electrically conductive coupling element can also be manufactured using printed circuit board technology, analogous to the circuit carrier, in order to achieve the necessary partial coverage of the receiving coils.In this case, the at least one electrically conductive coupling element can be manufactured such that an electrically conductive surface is arranged above a first receiving coil of the at least one coil pair, while only non-conductive carrier material is arranged above the second receiving coil of the at least one coil pair. Alternatively, the at least one electrically conductive coupling element can be designed as a busbar overmolded with plastic or as an injection-molded circuit carrier (MID: Molded Interconnect Devices).

[0023] In a further advantageous embodiment of the inductive measuring arrangement, at least three coil pairs, each enclosed by a planar transmitting coil, can form a sensor array that can be at least partially covered by a common electrically conductive coupling element or by two different electrically conductive coupling elements. The at least one evaluation and control unit can be further configured to receive and evaluate the measurement signals induced in the multiple coil pairs of the at least one receiving structure and to determine a spatial position of the movable body based on the evaluation. This allows a multi-channel design to be implemented, which advantageously enables an improved relationship between the actuating force applied to the movable body and the movement detected by the inductive measuring arrangement.This allows different forces acting on the movable body or on the pedal plate to be detected via the sensor array, resulting in tilting in two axes, as well as centering of the actuation force and the current distance or a change in the distance between the circuit carrier and the at least one electrically conductive coupling element. By determining the spatial position of the movable body, which can usually vary repeatedly during actuation by the user, it is possible to reliably detect whether the pedal plate is being actuated at all. This makes it possible to compensate for drift during operation, which can be caused, for example, by aging.This also enables error detection, for example, in the event of changes in the temperature behavior of the individual channels, as well as the detection of contamination in the air space between the at least one electrically conductive coupling element and the circuit carrier. Furthermore, the redundancy in the sensor array design allows for plausibility checks of the measurement signals, thus meeting high functional safety requirements. For example, degradation or failure of individual receiving coils can be reliably detected by comparing them with the other receiving coils.

[0024] Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description. In the drawings, like reference numerals designate components or elements that perform the same or similar functions. Short description of the drawings Fig. 1 shows a sectional view of a first embodiment of a pedal arrangement according to the invention for a vehicle with a first embodiment of an inductive measuring arrangement according to the invention. Fig. 2 shows a schematic plan view of the inductive measuring arrangement according to the invention from Fig. 1. Fig. 3 shows a schematic plan view of a first embodiment of a circuit carrier designed as a printed circuit board for the inductive measuring arrangement according to the invention from Fig. 1 and Fig. 2. Fig. 4 shows a schematic plan view of a second embodiment of the inductive measuring arrangement according to the invention. Fig. 5 shows a schematic plan view of a second embodiment of a circuit carrier designed as a printed circuit board for the inductive measuring arrangement according to the invention from Fig. 4. Fig. 6 shows a schematic plan view of a third embodiment of the inductive measuring arrangement according to the invention. Fig. 7 shows a sectional view of a second embodiment of a pedal arrangement according to the invention for a vehicle with a fourth embodiment of an inductive measuring arrangement according to the invention. Fig. 8 shows a schematic plan view of the inductive measuring arrangement according to the invention from Fig. 7. Fig. 9 shows a schematic plan view of a fifth embodiment of the inductive measuring arrangement according to the invention. Fig. 10 shows a schematic representation of an electrically conductive coupling element for the inductive measuring arrangement according to the invention from Fig. 9. Fig. 11 shows a schematic electrical block diagram of the inductive measuring arrangement according to the invention. Fig. 12 shows a schematic measurement signal-distance characteristic diagram with characteristics of two coil pairs of the inductive measuring arrangement according to the invention. Embodiments of the invention

[0025] As from Fig. 1 to 9, the illustrated embodiments of an inductive measuring arrangement 10, 10A, 10B, 10C, 10D, 10E according to the invention each comprise at least one evaluation and control unit 11, a circuit carrier 7 on which at least one transmitting structure 12 and at least one receiving structure 16 are arranged, and at least one electrically conductive coupling element 14.In this case, the at least one evaluation and control unit 11 is designed to couple a periodic electrical alternating signal into the at least one transmitting structure 12 and to receive a measurement signal MS induced based on an eddy current principle via the at least one electrically conductive coupling element 14 into the at least one receiving structure 16, which measurement signal MS represents a current distance A or a change in the distance A between the circuit carrier 7 and the at least one electrically conductive coupling element 14, and to generate and output an output signal AS based on the measurement signal MS.

[0026] The current distance A between the circuit carrier 7 and the at least one electrically conductive coupling element 14 determines a degree of coupling between the at least one transmitting structure 12 and the at least one receiving structure 16. A relative movement between the circuit carrier 7 and the at least one electrically conductive coupling element 14 changes the current distance between the circuit carrier 7 and the at least one electrically conductive coupling element 14 and thus the measurement signal MS induced in the at least one receiving structure 16. Here, the at least one electrically conductive coupling element 14 or the circuit carrier 7 is coupled to a movable body 3, which is movable against a force of at least one spring element 15.The at least one evaluation and control unit 11 is further designed to generate and output a further output signal based on the measurement signal MS and on predetermined properties of the at least one spring element 15, which represents a currently acting actuating force F on the movable body 3. In the illustrated embodiments, a common evaluation and control unit 11 is designed to generate the output signals AS of the respective inductive measuring arrangement 10, 10A, 10B, 10C, 10D, 10E. In the embodiments shown in . Fig. 1 and Fig. In the embodiments of the pedal arrangement 1 for a vehicle shown in Fig. 7, the movable body 3 is a pedal plate 3A.

[0027] As from Fig. 1 and Fig. As can be further seen in Figure 7, the illustrated embodiments of a pedal arrangement 1, 1A, 1B according to the invention for a vehicle each comprise a movably mounted pedal plate 3A, which can be actuated against a force of at least one spring element 15 over a predetermined small axial actuation path, a circuit carrier 7 and at least one inductive measuring arrangement 10, 10A, 10B, 10C, 10D, 10E, which is designed to detect the actuation of the pedal plate 3A and the corresponding axial actuation path. As can be seen from Fig. 1 and Fig. 7, the evaluation and control unit 11 in the illustrated embodiments of the pedal arrangement 1, 1A, 1B is arranged on a bottom side of the circuit carrier 7. As can be seen from Fig. 1 and Fig. 7, in the illustrated embodiments of the pedal arrangement 1, 1A, 1B, the at least one electrically conductive coupling element 14 is coupled to the pedal plate 3A and is moved along with the pedal plate 3A when the latter is actuated.

[0028] In alternative embodiments of the pedal arrangement 1 (not shown), the circuit carrier 7 is coupled to the movable body 3 or the pedal plate 3A and is moved when the movable body 3 or the pedal plate 3A is actuated.

[0029] As from Fig. 1 and Fig. As can be further seen in Figure 7, in the illustrated embodiments of the pedal arrangement 1A, 1B, the circuit carrier 7 with the at least one transmitting structure 12 and the at least one receiving structure 16 is arranged in a housing 9. In addition, several spring elements 15 of the illustrated embodiments of the pedal arrangement 1A, 1B are each designed as helical springs 15A, which are supported on a carrier 5 designed as a base plate 5A. The base plate 5A forms the bottom of the housing 9.

[0030] As from Fig. 1, in the illustrated first embodiment of the pedal arrangement 1A, an electrically conductive coupling element 14 is arranged on a holding structure 4 designed as a holding plate 4A, which is coupled or connected to the pedal plate 3A via connecting webs 3.1. In this case, the connecting webs 3.1 are guided through a cover of the housing 9 (not shown in more detail). As a result, the coupling element 14 is arranged between the circuit carrier 7 and the pedal plate 3A and the distance A between the coupling element 14 and the circuit carrier 7 decreases when the actuating force F is applied to the pedal plate 3A. End regions of the holding plate 4 form stops 4.1, which in combination with the cover of the housing 9 define an illustrated starting position of the holding plate 4 and thus of the pedal plate 3A.The spring elements 15, designed as helical springs 15A, act as compression springs and press the retaining plate 4 against the cover of the housing 9 into the illustrated initial position. As can be seen from . Fig. 1, the circuit carrier 7 is firmly connected to the base plate 5A via unspecified spacer elements.

[0031] As from Fig. 1 to 9, the at least one transmitting structure 12 in the illustrated embodiments comprises at least one planar transmitting coil 13, 13A, 13B, 13C, 13D. The at least one receiving structure 16 comprises at least one planar receiving coil 17, 17A, 17B. In addition, the circuit carrier 7 is designed as a multi-layer printed circuit board 7A, 7B, 7C. Here, the at least one planar transmitting coil 13, 13A, 13B, 13C, 13D and the at least one planar receiving coil 17, 17A, 17B are arranged in several layers of the printed circuit board 7A. The sections of the at least one planar transmitting coil 13, 13A, 13B, 13C, 13D and the at least one planar receiving coil 17, 17A, 17B arranged in different layers are electrically contacted with one another via vias 13,1, 17.1 and connected in series.

[0032] In the illustrated embodiments of the inductive measuring arrangement 10, 10A, 10B, 10C, 10D, 10E, the at least one receiving structure 16 comprises at least one coil pair 18, 18A, 18B, 18C, 18D, which comprises two adjacently arranged planar receiving coils 17, 17A, 17B with opposing windings, which are electrically connected in series. This means that the windings of one of the two planar receiving coils 17, 17A, 17B run clockwise, and the windings of the other of the two planar receiving coils 17, 17A, 17B run counterclockwise. Ideally, the area spanned by the receiving coil 17, 17A, 17B with clockwise windings is exactly as large as the area spanned by the receiving coil 17, 17A, 17B with counterclockwise windings.In this way, suppression of external interference magnetic fields is achieved because, in total, no voltage is induced in the receiving coils 17, 17A, 17B by the interference fields, or the voltages induced in the partial windings add up to zero.

[0033] The at least one planar transmitting coil 13, 13A, 13B, 13C, 13D of a corresponding transmitting structure 12 geometrically encloses the at least one coil pair 18, 18A, 18B, 18C, 18D of the at least one receiving structure 16. The most important property of the at least one planar transmitting coil 13, 13A, 13B, 13C, 13D is the provision of an inductance. This inductance depends primarily on the external dimensions (height and width) of the at least one planar transmitting coil 13, 13A, 13B, 13C, 13D as well as on the number of turns. Typical external dimensions are in the range of 10 mm by 10 mm. The area spanned by the at least one transmitting coil 13, 13A, 13B, 13C, 13D can be rectangular, circular, elliptical, or another suitable shape. The planar receiving coils 17, 17A, 17B of the individual coil pairs 18, 18A, 18B, 18C, 18D are geometrically located within the corresponding planar transmitting coil 13, 13A, 13B, 13C, 13D.The connections of the receiving coils 17, 17A, 17B are led out of the corresponding planar transmitting coil 13, 13A, 13B, 13C, 13D and connected to the at least one evaluation and control unit 11. The planar receiving coils 17, 17A, 17B of a coil pair 18, 18A, 18B, 18C, 18D can have a geometric polygonal shape, preferably a geometric rectangular shape or a geometric triangular shape, or a geometric circular shape, a geometric semicircular shape, or a geometric elliptical shape. Of course, the planar receiving coils 17, 17A, 17B can also have another suitable geometric shape.

[0034] As from Fig. As can be further seen in Figures 1 to 9, the at least one electrically conductive coupling element 14, 14A, 14B at least partially covers a surface spanned by the at least one coil pair 18, 18A, 18B, 18C, 18D and a surface spanned by the at least one planar transmitting coil 13, 13A, 13B, 13C, 13D. The geometric shape of the at least one electrically conductive coupling element 14, 14A, 14B is preferably based on the same geometric shape as the receiving coils 17, 17A, 17B.

[0035] As from Fig. 2 and Fig. 3, the illustrated first embodiment of the inductive measuring arrangement 10A comprises a circuit carrier 7 designed as a multi-layer printed circuit board 7A, shown transparently, with a receiving structure 16, which has two coil pairs 18A, 18B, each with two rectangular planar receiving coils 17A, 17B, each with eight turns, and a transmitting structure 12, which has a rectangular planar transmitting coil 13 with ten turns, and a rectangular electrically conductive coupling element 14. Here, the planar receiving coils 17A, 17B of the two coil pairs 18A, 18B and the planar transmitting coil 13 of the transmitting structure are each arranged in two layers of the printed circuit board 7A. As can be seen in particular from Fig. 3, a first planar receiving coil 17A of a first coil pair 18A on the left in the illustration is arranged above a second planar receiving coil 17B of the first coil pair 18A. The windings of the first planar receiving coil 17A of the first coil pair 18A run clockwise, and the windings of the second planar receiving coil 17B of the first coil pair 18A run counterclockwise. A first planar receiving coil 17A of a second coil pair 18B on the right in the illustration is arranged above a second planar receiving coil 17B of the second coil pair 18B. The windings of the first planar receiving coil 17A of the second coil pair 18B run counterclockwise, and the windings of the second planar receiving coil 17B of the second coil pair 18B run clockwise. As can be seen from Fig. 2 and Fig. 3, the planar transmitting coil 13 geometrically encloses the planar receiving coils 17A, 17B of the two coil pairs 18A, 18B. The planar receiving coils 17A, 17B of the two coil pairs 18A, 18B each have eight turns. As can be seen from Fig. 2, the rectangular electrically conductive coupling element 14 covers an upper half of the planar transmitting coil 13 and the two first planar receiving coils 17A of the two coil pairs 18A, 18B.

[0036] As from Fig. 4 and Fig. 5, the illustrated second embodiment of the inductive measuring arrangement 10B comprises, analogously to the first embodiment, a circuit carrier 7 designed as a multi-layer printed circuit board 7B, shown transparently, with a receiving structure 16, which has two coil pairs 18A, 18B, each with two triangular planar receiving coils 17A, 17B, each with eight turns, and a transmitting structure 12, which has a rectangular planar transmitting coil 13 with ten turns, and a triangular electrically conductive coupling element 14. Here, the planar receiving coils 17A, 17B of the two coil pairs 18A, 18B and the planar transmitting coil 13 of the transmitting structure are each arranged in two layers of the printed circuit board 7A. As can be seen in particular from Fig. 5, a first planar receiving coil 17A of a first coil pair 18A shown at the top of the illustration is arranged to the left of a second planar receiving coil 17B of the first coil pair 18A. The windings of the first planar receiving coil 17A of the first coil pair 18A run clockwise, and the windings of the second planar receiving coil 17B of the first coil pair 18A run counterclockwise. A first planar receiving coil 17A of a second coil pair 18B shown at the bottom of the illustration is arranged to the left of a second planar receiving coil 17B of the second coil pair 18B. The windings of the first planar receiving coil 17A of the second coil pair 18B run counterclockwise, and the windings of the second planar receiving coil 17B of the second coil pair 18B run clockwise. As from Fig. 4 and Fig. 5, the planar transmitting coil 13 geometrically encloses the receiving coils 17A, 17B of the two coil pairs 18A, 18B. The planar receiving coils 17A, 17B of the two coil pairs 18A, 18B each have eight turns. As can be seen from Fig. 4, the triangular electrically conductive coupling element 14 covers a right quarter of the planar transmitting coil 13 and the two second planar receiving coils 17B of the two coil pairs 18A, 18B.

[0037] As from Fig. 6, the illustrated third embodiment of the inductive measuring arrangement 10C comprises a circuit carrier 7 designed as a multi-layer printed circuit board 7C with a receiving structure 16, which has four coil pairs 18A, 18B, 18C, 18D, each with two triangular planar receiving coils 17A, 17B, and a transmitting structure 12, which has four rectangular planar transmitting coils 13A, 13B, 13C, 13D, and a rectangular, here square, electrically conductive coupling element 14, which is shown transparently. The four planar transmitting coils 13A, 13B, 13C, 13D each enclose one of the coil pairs 18A, 18B, 18C, 18D, so that a sensor array 19 with four basic cells is created, each consisting of a planar transmitting coil 13A, 13B, 13C, 13D and a coil pair 18A, 18B, 18C, 18D.

[0038] As from Fig. 6, the two triangular planar receiving coils 17A, 17B of a first coil pair 18A arranged at the top left in the illustration are geometrically enclosed by a first planar transmitting coil 13A. Here, a first triangular planar receiving coil 17A is arranged to the left of a second triangular planar receiving coil 17B. The two triangular planar receiving coils 17A, 17B of a second coil pair 18B arranged at the bottom left in the illustration are geometrically enclosed by a second planar transmitting coil 13B. Here, a first triangular planar receiving coil 17A is arranged to the left of a second triangular planar receiving coil 17B. The two triangular planar receiving coils 17A, 17B of a third coil pair 18C arranged at the top right in the illustration are geometrically enclosed by a third planar transmitting coil 13C.Here, a first triangular planar receiving coil 17A is arranged to the right of a second triangular planar receiving coil 17B. The two triangular planar receiving coils 17A, 17B of a fourth coil pair 18D arranged at the bottom right in the illustration are geometrically enclosed by a fourth planar transmitting coil 13D. Here, a first triangular planar receiving coil 17A is arranged to the right of a second triangular planar receiving coil 17B. As can be seen from . Fig. 6, the square electrically conductive coupling element 14 in the illustrated embodiment is arranged tilted by 90°, so that it covers half of the four planar transmitting coils 13A, 13B, 13C, 13D and the second planar receiving coil 17B of the four coil pairs 18A, 18B, 18C, 18D.

[0039] Here, the evaluation and control unit 11 is further designed to receive and evaluate the measurement signals MS induced in the multiple coil pairs 18A, 18B, 18C, 18D of the receiving structure 16 and, based on the evaluation, to determine a spatial position of the movable body 3 or of the electrically conductive coupling element 14 coupled to the movable body 3. This makes it possible to implement a multi-channel structure and different force effects on the movable body 3 or on the pedal plate 3A or on the electrically conductive coupling element 14 can be detected via the sensor array 19. Using trigonometric functions, resulting tilts in two axes of the movable body 3 or the pedal plate 3A orof the electrically conductive coupling element 14 as well as a centering of the actuating force and the current distance A or a change in the distance A between the circuit carrier 7 and the electrically conductive coupling element 14 can be calculated.

[0040] As from Fig. 7, the circuit carrier 7 in the illustrated second embodiment of the pedal arrangement 1B is arranged between two electrically conductive coupling elements 14, 14A, 14B. In this case, a current first distance A1 between a first electrically conductive coupling element 14A and the circuit carrier 7 decreases upon actuation of the pedal plate 3A and a current second distance A2 between a second electrically conductive coupling element 14B and the circuit carrier 7 increases upon actuation of the pedal plate 3A. As can be seen from Fig. 7, in the illustrated second embodiment of the pedal arrangement 1B, analogous to the first embodiment of the pedal arrangement 1A, the first electrically conductive coupling element 14A is arranged on a holding structure 4 designed as a holding plate 4A, which is coupled or connected to the pedal plate 3A via connecting webs 3.1. As a result, the first coupling element 14A is arranged between the circuit carrier 7 and the pedal plate 3A and the first distance A1 between the first coupling element 14A and the circuit carrier 7 decreases when the actuating force F is applied to the pedal plate 3A. The second electrically conductive coupling element 14B is arranged between the circuit carrier 7 and the base plate 5A and is coupled or connected to the first electrically conductive coupling element 14A via connecting webs (not designated in more detail) which are guided through the circuit carrier 7.When the actuating force F is applied to the pedal plate 3A, the second distance A2 between the second coupling element 14B and the circuit carrier 7 increases. Analogous to the first exemplary embodiment of the pedal arrangement 1A, in the illustrated second exemplary embodiment of the pedal arrangement 1B, end regions of the holding plate 4 form stops 4.1 which, in combination with the cover of the housing 9, define an illustrated starting position of the holding plate 4 and thus of the pedal plate 3A. The spring elements 15, designed as helical springs 15A, act as compression springs and press the holding plate 4 against the cover of the housing 9 into the illustrated starting position. In addition, the circuit carrier 7 is firmly connected to the base plate 5A via spacer elements (not shown in more detail), which are designed to be higher than the spacer elements in the first exemplary embodiment.

[0041] In the Fig. 7 and Fig. In the fourth external embodiment of the inductive measuring arrangement 10D shown in FIG. 8, a circuit carrier 7 designed as a multilayer printed circuit board 7A, shown transparently, corresponds to the multilayer printed circuit board 7A of the first embodiment of the inductive measuring arrangement 10A. This means that the receiving structure 16 has two coil pairs 18A, 18B, each with two rectangular planar receiving coils 17A, 17B, each with eight turns, and the transmitting structure 12 has a rectangular planar transmitting coil 13 with ten turns, which geometrically encloses the planar receiving coils 17A, 17B of the two coil pairs 18A, 18B. In contrast to the first embodiment, the inductive measuring arrangement 10D in the fourth embodiment comprises two rectangular electrically conductive coupling elements 14A, 14B, between which the circuit carrier 7 is arranged.

[0042] As from Fig. 8, a first rectangular electrically conductive coupling element 14A partially covers an upper side of the circuit carrier 7. In this case, the first rectangular electrically conductive coupling element 14 covers an upper half of the planar transmitting coil 13 in the illustration and the two first planar receiving coils 17A of the two coil pairs 18A, 18B from above. A second rectangular electrically conductive coupling element 14B partially covers an underside of the circuit carrier 7. In this case, the second rectangular electrically conductive coupling element 14B covers a lower half of the planar transmitting coil 13 in the illustration and the two second planar receiving coils 17B of the two coil pairs 18A, 18B from below.This means that the second rectangular electrically conductive coupling element 14B covers the areas of the transmitting coil 13 and the receiving coils 17A, 17B of the two coil pairs 18A, 18B not covered by the first rectangular electrically conductive coupling element 14B. Thus, the current first distance A1 between the first electrically conductive coupling element 14A and the top side of the circuit carrier 7 decreases during a movement of the movable body 3 or the pedal plate 3A based on an acting actuating force F, and the current second distance A2 between the second electrically conductive coupling element 14B and the underside of the circuit carrier 7 increases during the movement of the movable body 3 or the pedal plate 3A based on the acting actuating force F. The second target covers the areas of the coil system not covered by the first target.

[0043] In the Fig. 9 and Fig. 10, a circuit carrier 7, illustrated transparently and designed as a multilayer printed circuit board 7A, corresponds to the multilayer printed circuit board 7B of the second exemplary embodiment of the inductive measuring arrangement 10B. This means that the receiving structure 16 has two coil pairs 18A, 18B, each with two triangular planar receiving coils 17A, 17B, each with eight turns, and the transmitting structure 12 has a rectangular planar transmitting coil 13 with ten turns, which geometrically encloses the planar receiving coils 17A, 17B of the two coil pairs 18A, 18B. In contrast to the second exemplary embodiment, the inductive measuring arrangement 10E in the fifth exemplary embodiment comprises two electrically conductive coupling elements 14A, 14B, between which the circuit carrier 7 is arranged.

[0044] As from Fig. 9, a first triangular electrically conductive coupling element 14A partially covers an upper side of the circuit carrier 7. In this case, the first triangular electrically conductive coupling element 14A covers a right-hand quarter of the planar transmitting coil 13 and the two second planar receiving coils 17B of the two coil pairs 18A, 18B from above. A second rectangular electrically conductive coupling element 14B with a triangular cutout, which corresponds to the triangular shape of the first electrically conductive coupling element 14A, as can be seen from Fig. 10, partially covers an underside of the circuit carrier 7. In this case, the second electrically conductive coupling element 14B covers the remaining three-quarters of the planar transmitting coil 13 and the two first planar receiving coils 17A of the two coil pairs 18A, 18B from below. This means that the second electrically conductive coupling element 14B covers the areas of the transmitting coil 13 and the receiving coils 17A, 17B of the two coil pairs 18A, 18B that are not covered by the first electrically conductive coupling element 14B. The current first distance A1 between the first electrically conductive coupling element 14A and the upper side of the circuit carrier 7 decreases during a movement of the movable body 3 orthe pedal plate 3A, and the current second distance A2 between the second electrically conductive coupling element 14B and the underside of the circuit carrier 7 increases during the movement of the movable body 3 or the pedal plate 3A based on the acting actuating force F.

[0045] In the first, second, fourth and fifth embodiments of the inductive measuring arrangement 10A, 10B, 10D, 10E, the receiving structure 16 comprises two coil pairs 18A, 18B, so that the evaluation and control unit 11 receives a first measuring signal MS output by the first coil pair 18A, the course of which in Fig. 12 is designated K1, and a second measuring signal MS output by the second coil pair 18B, the course of which is shown in Fig. 12 designated K2, receives and evaluates. The two measurement signals MS have different polarity. The two measurement signals MS can be evaluated for plausibility checks or to implement homogeneous redundancy. Preferably, to monitor the evaluation in the case of different polarity, a sum signal can be evaluated, which should have a value of "zero" within a predeterminable tolerance range. To implement homogeneous redundancy, two separate evaluation and control units 11 can be used, each of which receives and evaluates one of the measurement signals MS. A common electrically conductive coupling element 14 can be used to generate the two measurement signals MS.

[0046] As from Fig.11, the evaluation and control unit 11 in the illustrated embodiment is designed as an ASCI component 11A (ASIC: Application Specific Integrated Circuit) and comprises an oscillator circuit 11.1, a demodulator circuit 11.2, a calculation unit 11.3, an output driver 11.4 and a supply circuit which generates and provides the internal voltages required to supply and operate the evaluation and control unit 11. The transmitting coil 13 is connected to discrete capacitors C1, C2 to form an electrical excitation resonant circuit. The evaluation and control unit 11, designed as an ASIC component 11A, is used to maintain the resonant oscillation in the excitation resonant circuit and to evaluate the receiver coil signals.The ASIC module 11A has at least one or more drivers and one or more connections for the at least one transmitting coil 13 and at least one connection for the at least one receiving coil 17, 17A, 17B. In the illustrated embodiment, the ASIC module 11A comprises connections for several receiving coils 17A, 17B and for several coil pairs 18, 18A, 18B, 18C, 18D. The demodulator circuit 11.2 of the ASIC module 11A performs a demodulation of the amplitude-modulated receiving coil signals, and the calculation unit 11.3 calculates the distance A between the at least one electrically conductive coupling element 14 and the circuit carrier 7 from the level of the induced voltage. If necessary, the calculation unit 11.3 also performs a linearization of the characteristic curves K1, K2. The output signal AS can be passed on to a higher-level control unit in analog or digital form via the output driver 11.4.In addition, a temperature sensor in the ASIC module 11A can be used to compensate for thermal drifts, for example to compensate for impedance changes of the at least one electrically conductive coupling element 14 or the planar receiving coils 17A, 17B or transmitting coils 13.

[0047] The high-frequency current flow in the at least one transmitting coil 13 generates a magnetic field with the same frequency. This magnetic field is penetrated by the at least one electrically conductive coupling element 14. As a result, shielding eddy currents are induced within a thin surface layer of the coupling element 14. According to Lenz's law, these shielding currents are directed opposite to their source (excitation field) and thus weaken the excitation field. The coupling element 14 is not located over the entire coil surface of the coil pairs 18, 18A, 18B, 18C, 18D, but only over a certain portion. In this way, an imbalance of the induced partial voltages within a coil pair 18, 18A, 18B, 18C, 18D is achieved. The induced voltage is therefore not equal to zero and depends on the air gap or distance between the electrically conductive coupling element 14 and the circuit carrier 7.The geometry of the at least one electrically conductive coupling element 14 depends significantly on the shape of the receiver coils 17, 17A, 17B and just covers a receiver coil 17, 17A, 17B of a corresponding coil pair 18, 18A, 18B, 18C, 18D as well as part of the transmitter coil 13. In principle, all materials with a conductivity above 1 MS / m are suitable as materials for the at least one electrically conductive coupling element 14, including copper, aluminum, and steel. The thickness of the electrically conductive coupling element 14 depends on the resonant frequency of the resonant circuit and the conductivity of the material used and should be at least in the range of the skin depth. Implementation using a standard printed circuit board is possible and very cost-effective. The relationship between induced receiver coil voltage and air gap or distance A between the at least one electrically conductive coupling element 14 and the circuit carrier is non-linear.By using two electrically conductive coupling elements 14, 14A, 14B, between which the circuit carrier 7 is arranged, the relationship can be largely linearized. Further linearization can be achieved by an embodiment with a non-plane-parallel electrically conductive coupling element 14, for example, with a hemispherical or parabolic electrically conductive coupling element 14. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 198 11 268 A1

[0005]

Claims

[1] Inductive measuring arrangement (10) with at least one evaluation and control unit (11), a circuit carrier (7) on which at least one transmitting structure (12) and at least one receiving structure (16) are arranged, and at least one electrically conductive coupling element (14), wherein the at least one evaluation and control unit (11) is designed to couple a periodic electrical alternating signal into the at least one transmitting structure (12) and to receive a measuring signal (MS) induced into the at least one receiving structure (16) via the at least one electrically conductive coupling element (14) based on an eddy current principle, which measuring signal represents a current distance (A) or a change in the distance (A) between the circuit carrier (7) and the at least one electrically conductive coupling element (14), and to generate and output an output signal (AS) based on the measuring signal (MS). [2] Inductive measuring arrangement (10) according to claim 1,characterized by in that the at least one electrically conductive coupling element (14) or the circuit carrier (7) is coupled to a movable body (3) which is movable against a force of at least one spring element (15), wherein the at least one evaluation and control unit (11) is further designed to generate and output a further output signal based on the measurement signal (MS) and on predetermined properties of the at least one spring element (15), which further output signal represents a currently acting actuating force (F) on the movable body (3). [3] Inductive distance measuring arrangement (10) according to claim 2, characterized by that the movable body (3) is a pedal plate (3A). [4] Inductive distance measuring arrangement (10) according to one of claims 1 to 3, characterized bythat the at least one transmitting structure (12) comprises at least one planar transmitting coil (13) and the at least one receiving structure (16) comprises at least one planar receiving coil (17). [5] Inductive measuring arrangement (10) according to one of claims 1 to 4, characterized by that the circuit carrier (7) is designed as a multi-layer printed circuit board (7A). [6] Inductive measuring arrangement (10) according to claims 4 and 5, characterized by that the at least one planar transmitting coil (13) and / or the at least one planar receiving coil (17) are arranged in several layers of the printed circuit board (7A), wherein the sections of the at least one planar transmitting coil (13) and / or the at least one planar receiving coil (17) arranged in different layers are electrically contacted with one another via vias (13,1, 17.1) and are connected in series. [7] Inductive measuring arrangement (10) according to one of claims 2 to 6, characterized byin that the circuit carrier (7) is arranged between two electrically conductive coupling elements (14), wherein a current first distance (A1) between a first electrically conductive coupling element (14A) and the circuit carrier (7) decreases during a movement of the movable body (3) based on an acting actuating force (F), and a current second distance (A2) between a second electrically conductive coupling element (14B) and the circuit carrier (7) increases during the movement of the movable body (3) based on the acting actuating force (F). [8] Inductive measuring arrangement (10) according to one of claims 1 to 7, characterized by that the at least one receiving structure (16) comprises at least one coil pair (18) which comprises two planar receiving coils (17) arranged next to one another with opposite windings which are electrically connected in series. [9] Inductive measuring arrangement (10) according to claim 8, characterized by that the planar receiving coils (17) of a coil pair (18) have a geometric polygon shape or a geometric circular shape or a geometric semicircular shape or a geometric elliptical shape. [10] Inductive measuring arrangement (10) according to claim 8 or 9, characterized by that the at least one planar transmitting coil (13) of a corresponding transmitting structure (12) geometrically encloses the coil pair (18) of the at least one receiving structure (16). [11] Inductive measuring arrangement (10) according to one of claims 8 to 10, characterized by that the at least one electrically conductive coupling element (14) at least partially covers a surface spanned by the at least one coil pair (18) and a surface spanned by the at least one planar transmitting coil (13). [12] Inductive measuring arrangement (10) according to one of claims 8 to 11, characterized bythat the at least one electrically conductive coupling element (14) is based on the same geometric shape as the at least one receiving coil (17). [13] Inductive measuring arrangement (10) according to one of claims 8 to 12, characterized by in that at least three coil pairs (18), each enclosed by a planar transmitting coil (13), form a sensor array (19) which is at least partially covered by a common electrically conductive coupling element (14) or by two different electrically conductive coupling elements (14). [14] Inductive measuring arrangement (10) according to claim 13, characterized by that the at least one evaluation and control unit is further designed to receive and evaluate the measurement signals (MS) induced in the plurality of coil pairs (18) of the at least one receiving structure (16) and to determine a spatial position of the movable body (3) based on the evaluation. [15] Pedal arrangement (1) for a vehicle, with at least one movably mounted pedal plate (3A) which can be actuated against a force of at least one spring element (15) over a predetermined axial actuation path, and at least one inductive measuring arrangement (10) which is designed and constructed according to one of claims 1 to 14 to detect the actuation of the pedal plate (3A) and the corresponding actuation path.

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