Inductive Linear Displacement Sensor Arrangement for a Vehicle

Abstract

An inductive linear displacement sensor arrangement includes a movable coupling device coupled to a movable body, an electrically conductive coupling element, and a stationary circuit carrier. The circuit carrier includes an excitation structure and a receiving structure, which extend along a displacement path of the coupling device. An evaluation and control unit is designed to evaluate a measurement signal induced in the receiving structure and to determine the current position of the coupling device and of the body. The coupling device comprises a slider on which the electrically conductive coupling element is arranged. The slider is mounted for sliding movement in a plane of displacement via the path of displacement of the coupling device on two parallel guide elements, one of which guides the slider of the coupling device along the displacement path, and another of which is a sliding guide which prevents the slider from tilting and/or twisting.

Claims

1. An inductive linear displacement sensor arrangement for a vehicle, comprising: at least one movable coupling device which is coupled to a movable body and comprises at least one electrically conductive coupling element; and a stationary circuit carrier, wherein the stationary circuit carrier comprises at least one excitation structure and at least one receiving structure which extend along a displacement path of the at least one movable coupling device; an evaluation and control unit is designed to evaluate at least one measurement signal induced in the at least one receiving structure and to determine a current position of the at least one movable coupling device and of the movable body; the at least one movable coupling device comprises a slider on which the at least one electrically conductive coupling element is arranged; the slider is mounted, via the path of displacement of the at least one movable coupling device, on two parallel guide elements such that the slider slides in a plane of displacement which extends parallel to the at least one receiving structure of the stationary circuit carrier at a predeterminable, constant distance; one of the two guide elements is configured to guide the slider free from backlash along the path of movement; and another of the two guide elements is configured as a sliding guide and prevents the slider from tilting and/or twisting.

2. The inductive linear displacement sensor arrangement according to claim 1, wherein the two guide elements are each designed as cylindrical guide pins.

3. The inductive linear displacement sensor arrangement according to claim 1, wherein the two guide elements are mounted in parallel in a plastic frame which defines the path of displacement of the at least one coupling device and supports the circuit carrier.

4. The inductive linear position displacement arrangement according to claim 1, wherein the slider is designed as a plastic injection-molded component having two guide devices which form sliding zones for the guide elements.

5. The inductive linear displacement sensor arrangement according to claim 4, wherein a first of the two guide devices is designed as a guide opening through which one of the two guide elements runs free from backlash.

6. The inductive linear displacement sensor arrangement according to claim 5, wherein a second of the two guide devices is designed as a guide fork through which another of the two guide elements runs.

7. The inductive linear displacement sensor arrangement according to claim 1, wherein the slider is configured to be coupled to the movable body by at least one driver.

8. The inductive linear displacement sensor arrangement according to claim 1, wherein: the at least one excitation structure is coupled to at least one oscillator circuit which is configured to, during operation, couple a periodic alternating signal into the at least one excitation structure; and the at least one movable coupling device is configured to influence an inductive coupling between the at least one excitation structure and the at least one receiving structure as a function of the current position of the at least one movable coupling device.

9. The inductive linear displacement sensor arrangement according to claim 1, wherein the at least one excitation structure comprises at least one excitation coil, which runs circumferentially on an edge of the at least one circuit carrier.

10. The inductive linear displacement sensor arrangement according to claim 1, wherein the at least one receiving structure comprises at least one receiving coil.

11. The inductive linear displacement sensor arrangement according to claim 10, wherein the at least one receiving coil comprises a periodically repeating loop structure, which is distributed over a plurality of layers of the stationary circuit carrier.

12. The inductive linear displacement sensor arrangement according to claim 1, wherein: the at least one movable coupling device comprises a first and a second movable coupling device; the first and second movable coupling devices are mounted, one behind the other, on the two parallel guide elements such that the first and second movable coupling devices are movable in a sliding manner; a first guide element of the two parallel guide elements guides a first slider of the first movable coupling device along the displacement path free from backlash; a second guide element of the two parallel guide elements is configured as a sliding guide for the first slider and prevents the first slider from tilting and/or twisting; and the second guide element (i) guides a second slider of the second movable coupling device free from backlash along the path of displacement and the first guide element, (ii) is used as a sliding guide for the second slider, and (iii) prevents tilting and/or twisting of the second slider.

13. The inductive linear displacement sensor arrangement according to claim 12, wherein the two sliders of the two coupling devices are each designed as L-shaped injection-molded plastic components and are arranged nested within one another.

14. The inductive linear displacement sensor arrangement according to claim 1, wherein the at least one electrically conductive coupling element is designed as one of a stamped bent part, an electrically conductive foil, an electrically conductive coating, and an electrically conductive structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 shows a schematic perspective view of an exemplary embodiment of an inductive linear displacement sensor arrangement for a vehicle according to the disclosure with a circuit carrier shown in transparent form.

[0022] FIG. 2 shows a schematic sectional view of the inductive linear displacement sensor arrangement of FIG. 1 according to the disclosure without plastic frame.

[0023] FIG. 3 shows a schematic perspective view of two coupling devices of the inductive linear displacement sensor arrangement according to the disclosure from FIGS. 1 and 2, arranged on two guide elements.

[0024] FIG. 4 shows a schematic perspective view of two sliders of the coupling devices of FIG. 3 arranged on two guide elements.

[0025] FIG. 5 shows an enlarged perspective view of the sliders of FIG. 4.

DETAILED DESCRIPTION

[0026] As can be seen from FIGS. 1 through 5, the illustrated exemplary embodiment of an inductive linear displacement sensor arrangement 1 for a vehicle according to the disclosure comprises at least one movable coupling device 10 coupled to a movable body (not shown), which comprises at least one electrically conductive coupling element 12, and a stationary circuit carrier 3. The circuit carrier 3 comprises at least one excitation structure 4 and at least one receiving structure 5 extending along a path of displacement of the at least one coupling device 10, 10A, 10B. An evaluation and control unit 7 evaluates at least one measurement signal induced in the at least one receiving structure 5 and determines the current position of the at least one coupling device 10, 10A, 10B and the movable body. The at least one movable coupling device 10, 10A, 10B comprises a slider 20, 20A, 20B on which the at least one electrically conductive coupling element 12 is arranged. In this case, the slider 20, 20A, 20B is mounted for sliding movement over the path of displacement of the at least one coupling device 10, 10A, 10B on two parallel guide elements 14 in a plane of displacement which extends parallel to the at least one receiving structure 5 of the circuit carrier 3 at a predeterminable constant distance LS. One of the two guide elements 14, 14A, 14B guides the slider 20, 20A, 20B of the at least one coupling device 10, 10A, 10B free from backlash along the path of displacement and another of the two guide elements 14, 14A, 14B is used as a sliding guide and prevents the slider 20, 20A, 20B from tilting and/or twisting.

[0027] As can be further seen from FIGS. 1 through 4, the two guide elements 14, 14A, 14B in the illustrated exemplary embodiment of the inductive linear displacement sensor arrangement 1 are each designed as cylindrical guide pins. The guide elements 14, 14A, 14B, designed as cylindrical guide pins, are mounted in parallel in a plastic frame 16, which defines the path of displacement of the at least one coupling device 10, 10A, 10B and supports the circuit carrier 3.

[0028] As can be further seen from FIGS. 1 through 5, the inductive linear displacement sensor arrangement 1 in the illustrated exemplary embodiment comprises two coupling devices 10, 10A, 10B, which are mounted one behind the other on the two guide elements 14, 14A, 14B for sliding displacement. In this case, a first guide element 14A guides a first slider 20A of a first coupling device 10A along the displacement path free from backlash, and a second guide element 14B is used as a sliding guide for the first slider 20A and prevents the first slider 20A from tilting and/or twisting. In addition, the second guide member 14B guides a second slider 20B of a second coupling device 10B along the displacement path free from backlash, and the first guide member 14A is used as a sliding guide for the second slider 20B and prevents the second slider 20B from tilting and/or twisting. The two sliders 20, 20A, 20B of the two coupling devices 10, 10A, 10B are each designed as injection-molded plastic components with two guide devices 22, 22A, 22B, which form sliding zones 28, 28A, 28B for the guide elements 14, 14A, 14B. In the illustrated exemplary embodiment, the two sliders 20, 20A, 20B of the two coupling devices 10, 10A, 10B each have an L-shape and are arranged nested within each other. The two sliders 20, 20A, 20B can move independently on the guide elements 14, 14A, 14B.

[0029] As can be further seen in particular from FIGS. 4 and 5, a first guide device 22A of the two sliders 20, 20A, 20B is each designed as a guide opening 24 through which one of the two guide elements 14, 14A, 14B runs free from backlash. A second guide device 22B of each of the two sliders 20, 20A, 20B is designed as a guide fork 26 through which another of the two guide elements 14, 14A, 14B runs. In the illustrated exemplary embodiment, the first guide element 14A runs free from backlash through the guide opening 24 of the first slider 20A and through the guide fork 26 of the second slider 20B. The second guide element 14B runs free from backlash through the guide opening 24 of the second slider 20B and through the guide fork 26 of the first slider 20A. In the illustrated exemplary embodiment, the guide openings 24 of the two sliders 20, 20A, 20B are formed by injection molding by a plurality of U-shaped recesses 24A, 24B, 24C which are formed sequentially on a first leg of the L-shaped sliders 20, 20A, 20B. In this case, adjacent U-shaped recesses 24A, 24B, 24C are rotated 180? relative to each other so that the openings of the U-shaped recesses 24A, 24B, 24C face in opposite directions. The associated connecting regions of the legs of the U-shaped recesses 24A, 24B, 24C are formed as first sliding zones 28A. In the illustrated exemplary embodiment, the guide forks 26 of the two sliders 20, 20A, 20B are formed at the end portion of a second leg of the L-shaped sliders 20, 20A, 20B. In this case, the two guide forks 26 each have three webs 26.1, 26.2, 26.3, which form two plane-parallel surfaces as second sliding zones 28.2. The webs 26.1, 26.2, 26.3 of the guide forks 26 are arranged alternately on opposite sides of the second leg of the L-shaped sliders 20, 20A, 20B. Doing so results in a small running clearance between the guide elements 14, 14A, 14B and the sliders 20, 20A, 20B, so that precise guidance of the sliders 20, 20A, 20B is possible.

[0030] Given the described design of the sliders 20, 20A, 20B and guide elements 14, 14A, 14B, the displacement of the electrically conductive coupling elements 12 mounted on the sliders 20, 20A, 20B is only one-dimensional. All other directions of displacement which are caused by, e.g., tilting, twisting, backlash, etc., can be minimized by the dual guidance and opposing support of the sliders 20, 20A, 20B. The movable structure enables independent displacement of the two L-shaped sliders 20, 20A, 20B within certain limits, although the 180? rotated installation position of the two sliders 20, 20A, 20B relative to each other means that completely free displacement is only possible in one opposite direction in each case. The L-shaped design of the sliders 20, 20A, 20B enables a cost-effective design of the plastic injection molded parts, also with regard to low tolerances, which can be manufactured as a tool-bound geometry.

[0031] The mechanical fixation of the guide elements 14, 14A, 14B takes place in the frame 16 made of plastic. The plastic materials of the frame 16 and the sliders 20, 20A, 20B are selected so that the sliders 20, 20A, 20B and the frame 16 behave thermally in a similar manner over the required temperature range. The plastic materials used can be adapted in terms of their material properties, so that a small running clearance and thus precise guidance of the sliders 20, 20A, 20B can be produced. The described exemplary embodiment of the slider 20, 20A, 20B is cost-optimized and manufactured as a simple cost-optimized plastic injection-molded part. Given that no slides, etc., are required, the slides 20, 20A, 20B can be produced in molds with multiple cavities. The material pairing between the fixed guide elements 14, 14A, 14B and the sliders 20, 20A, 20B is designed such that, on the one hand, only the smallest forces are required for displacement with low running clearance (e.g. <0.05 mm) and, on the other hand, wear between pins and sliders is also minimized. In the illustrated exemplary embodiment, the material pairing used is POM polymer (POM: PolyOxyMethylene) or PEEK polymer (PEEK: Polyetheretherketone) for the sliders 20, 20A, 20B and the frame 16 in combination with an alloyed stainless steel for the guide elements 14, 14A, 14B.

[0032] As can be further seen in particular from FIGS. 2 and 3, the at least one electrically conductive coupling element 12 is designed as a stamped and bent part 12A and is attached to the corresponding slider 20, 20A, 20B via hot caulking. Of course, other suitable fastening techniques can also be used. In the illustrated exemplary embodiment, two electrically conductive coupling elements 12 are arranged on each of the two slides 20, 20A, 20B at a distance from each other. The respective stamped and bent part 12A is designed such that drivers 12.1, which mechanically couple the sliders 20, 20A, 20B to the movable body not shown, are each formed as a clamp and can thus perform the function of a backlash-free and positive connection with the mechanical encoder system. The elastic properties of the metal are relevant in this case and determine the shape or dimensions of the clamp. This embodiment of the carrier 12.1 provides sufficient clearance in the contact surface with the mechanical encoder or the moving body in one plane to compensate for tolerances with regard to mechanics, components, assembly and temperature. This clearance is designed such that displacement is only possible in a two-dimensional plane which is perpendicular to the direction of displacement of the sliders 20, 20A, 20B. The mechanical encoder or the moving body can be, e.g., a pedal rod of a brake pedal.

[0033] In alternative exemplary embodiments (not shown), the at least one electrically conductive coupling element 12 is implemented as an electrically conductive foil or as an electrically conductive coating or as an electrically conductive structure and is applied directly to the corresponding slider 20, 20A, 20B.

[0034] In the illustrated exemplary embodiment, an excitation structure 4 is coupled to an oscillator circuit, (not shown in greater detail), which couples a periodic alternating signal to the excitation structure 4 during operation. The illustrated excitation structure 4 comprises an excitation coil that extends circumferentially along the edge of the at least one circuit carrier 3. The electrically conductive coupling elements 12 of the two sliders 20, 20A, 20B of the two coupling devices 10, 10A, 10B influence an inductive coupling between the excitation structure 4 and the receiving structure 5 depending on their current position and enable a differential detection or determination of the current position of the two coupling devices 10, 10A, 10B of the corresponding moving body. The receiving structure 5 shown comprises a plurality of receiving coils, each of which features a periodically repeating loop structure. The loop structures are distributed over multiple layers of the stationary circuit carrier 3 so that overlaps can be easily avoided. The sections of the repeating loop structures, arranged in different layers, are electrically connected to each other via vias.

[0035] As can be further seen in particular from FIGS. 1 and 2, the circuit carrier 3 comprises a first section arranged at the edge of the frame 16, in which the evaluation and control unit 7 is arranged, which is designed as an ASIC module, and a laterally arranged second section, on which electrical contact points 9 are arranged for contacting the inductive linear displacement sensor arrangement 1. In addition, the circuit carrier 3 comprises a third section inserted in the frame 16, on which the excitation coil of the excitation structure 14 and the reception coils of the receiving structure 5 are arranged. The surface extent of the third section of the circuit carrier 5 is adapted to the path of displacement of the sliders 20, 20A, 20B and the surfaces of the two coupling devices 10, 10A, 10B determined by the frame 3.