Electronic multi-channel force sensor

Abstract

The invention describes an electronic multi-channel force sensor having a sensing bolt and a sensing plate, wherein the sensing bolt can be adjusted from its neutral position in at least two operating directions, and when the operating force is removed, the sensing bolt returns to its neutral position again, the sensing plate is connected to the sensing bolt, and the sensing plate is deflectable relative to the printed circuit board by adjustment of the sensing bolt, the sensing plate has an electrical measuring system, the output signal of the electrical measuring system depends on the position of the sensing plate, wherein the sensing plate is integrally connected to a plurality of strip-shaped support elements, each of the support elements having an end portion configured as a circular hole, and wherein the sensing plate and the support elements are integrally cut freely from a metal plate.

Description

Technical Field

[0001] The invention relates to an electronic multi-way force sensor having a sensing bolt and a sensing plate, wherein the sensing bolt can be adjusted in at least two operating directions from its neutral position, and when the operating force is removed, the sensing bolt moves back to its neutral position, and has a sensing plate, which is connected to the sensing bolt and can be deflected relative to a printed circuit board by adjusting the sensing bolt, and has an electrical measuring system, the output signal of the measuring system depends on the position of the sensing plate.

[0002] Components of the electronic multi-way force sensor which do not directly belong to the printed circuit board are referred to below as sensor elements. Background Art

[0003] Multi-channel force sensors of this type are used in particular as input elements, for example in seat adjustment switches in motor vehicles. A detection device in the form of a capacitive multi-channel force sensor is known from German patent application DE 10 2014 014 021 A1, the entire content of which is hereby incorporated by reference into this document. The multi-channel force sensor described in DE 10 2014 014 021 A1 has a sensing bolt, which is rigidly connected to the upper part of a housing. Inside the housing, the sensing bolt is connected to a metal or metallized plate. When the sensing bolt is deflected, the metal or metallized plate is simultaneously deflected relative to a metallized surface on a printed circuit board, so that the capacitance value of the capacitor formed by the arrangement of the metal or metallized plate and the surface changes with the deflection of the sensing bolt. Since the upper part of the housing must be elastically deformed at the same time in order to deflect the sensing bolt, the multi-channel force sensor is very rigid, which is very ideal for some applications such as seat adjustment switches.

[0004] The sensor element of the multi-channel force sensor according to DE 10 2014 014 021 A1 can advantageously be manufactured completely or largely as an injection molded part, in which at least the housing and the sensing bolt are composed of plastic in one piece. The sensor element can also be designed to be made completely of metal, but the manufacturing costs are relatively high due to the difficulty in demoulding the housing. For some applications, in particular in motor vehicles, the relatively large space requirement for the housing is also disadvantageous.

[0005] The object of the invention is to create a universal, in particular simple, inexpensive and compact electronic multi-way force sensor having a simple, inexpensive and compact sensor element made completely of metal. Summary of the invention

[0006] According to the invention, this object is achieved in that the induction plate is integrally connected to a plurality of strip-shaped support elements, each of which has an end portion configured as an eyelet, and the induction plate and the support elements are integrally cut free from a metal plate.

[0007] The induction plate and the strip-shaped support plate elements can be cut freely from a single, preferably rectangular or in particular square, metal plate, preferably by a punching process.

[0008] An approximately four-leaf-clover-shaped induction plate is retained between the strip-shaped support elements, and the induction plate has four induction blades that are opposite to each other in pairs.

[0009] A strip-shaped support element connected in one piece to the sensor board allows a particularly simple arrangement of the sensor board, either at a mounting location opposite the printed circuit board or preferably directly on the printed circuit board.

[0010] The support element serves as a fixing element for fastening the induction plate and as a centering element for precisely positioning the induction plate. Therefore, the end portion of the support element forms a screwing eyelet or a centering eyelet, into which a bolt or a centering pin is inserted.

[0011] It is advantageous if at least two of the support elements are designed as fastening elements with screw-on eyes. It is also advantageous if, in the case of the support elements provided as centering elements, the centering eyes are designed as elongated holes.

[0012] A complete sensor element is created by connecting the sensing plate with the center of the vertically protruding sensing bolt. Since it does not have any parts that are difficult to demould, such as a housing, the sensor element can be made completely from metal in a simple and inexpensive manner. The production of metal facilitates a particularly rigid production of the multi-channel force sensor with a simple structure. The sensor element can be connected directly to the printed circuit board via its supporting elements. The electronic components for detecting the deflection of the sensing plate are arranged on the printed circuit board. The measuring system formed in this way can preferably consist of a plurality of conductor surfaces arranged on the printed circuit board, which conductor surfaces form capacitors with the sensing blades of the sensing plate, whose capacitance and capacitance changes can be detected to determine the adjustment of the sensing plate. In addition to acquiring the capacitance value, the change in distance can also be determined by other measuring principles, for example by optical methods.

[0013] The deflection of the sensor lever causes the sensor blade of the sensor plate to tilt relative to the support element and thus causes an increase or decrease in the distance between the sensor blade and the conductor surface arranged on the circuit board. The magnitude of the distance change is a measure of the applied force, which can be determined by electronic equipment not described in detail here.

[0014] The arrangement of four sensing blades ensures that at least four operating directions can be detected with only one sensor element. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Exemplary embodiments of the present invention will be shown and explained below with reference to the accompanying drawings. The sole drawing shows an exploded view of an electronic multi-channel force sensor designed according to the present invention. DETAILED DESCRIPTION

[0016] The illustrated multi-path force sensor functions according to the capacitive measuring principle and consists of a metallic sensor element 10 and a printed circuit board 20 , in particular on which a plurality of conductor surfaces 21 are applied.

[0017] The sensor element 10 has a substantially cylindrical sensing rod 11. A metal sensing plate 12 is connected to the lower end portion of the sensing rod 11, and when the longitudinal axis of the sensing rod 11 is deflected, the sensing plate 12 is deflected.

[0018] This changes the position of the sensing plate 12 relative to the conductor surfaces 21 arranged on the printed circuit board 20. Parts of the sensing plate 12 form capacitors with these conductor surfaces 21, the capacitance of which changes with the deflection of the sensing plate 12. The change in capacitance can be evaluated by electronic equipment (not shown here) in order to detect the change in position of the sensing plate 12 and thus the operating force acting on the sensing bolt 11. The deflection of the sensing bolt 11 can be achieved manually, for example, by means of an additional button cover (not shown here).

[0019] The lower part of the sensor element 10 is made of a square or rectangular metal plate, from which strip-shaped support elements 13, 14, 15, 16 are freely cut in the diagonal direction. The end portions of the support elements 13, 14, 15, 16 form screw holes 17 and centering holes 18, 19. The centering holes 18, 19 for centering the sensor element 10 are designed as holes 18 and long holes 19.

[0020] The portion of the metal plate integrally connected to the strip-shaped support elements 13 , 14 , 15 , 16 is formed into a sensing plate 12 approximately in the shape of a four-leaf clover, having four sensing blades 12 a facing each other in pairs, the center of which is firmly connected to a vertically protruding cylindrical sensing bolt rod 11 .

[0021] After assembly, the sensor element 10 is arranged on the upper side of the printed circuit board 20, and the screw holes 17 are connected to the screw holes 23 by bolts. For the precise positioning of the sensor element 10, the centering pins 22 arranged on the upper side of the printed circuit board 20 are also inserted into the centering holes 18, 19 of the sensor element 10.

[0022] In the neutral position of the sensor element 10 , the sensing blade 12 a is aligned slightly tilted upwards compared to the plane spanned by the support elements 13 , 14 , 15 , 16 , so that a relative movement is possible in all possible tilting directions.

[0023] 10 Sensor element

[0024] 11 Sensor bolt

[0025] 12 Induction board

[0026] 12a Induction blade

[0027] 13, 14, 15, 16 Support elements

[0028] 17 Tighten the eyelet

[0029] 18, 19 Centering holes

[0030] 18 holes

[0031] 19 Long hole

[0032] 20. PCB

[0033] 21 Conductor surface

[0034] 22 Locating pin

[0035] 23 Tightening hole

Claims

1. An electronic multi-way force sensor having a sensing rod (11) and a sensing plate (12), wherein the sensing rod (11) is adjustable from its neutral position in at least two operating directions, and when the operating force is removed, the sensing rod returns to its neutral position again, The sensing plate (12) is connected to the sensing bolt (11), and the sensing plate (12) is deflectable relative to a printed circuit board (20) by adjusting the sensing bolt (11), the printed circuit board having an electrical measuring system, the output signal of which depends on the position of the sensing plate (12), It is characterized in that The induction plate (12) is integrally connected to a plurality of strip-shaped support elements (13, 14, 15, 16), each of which has an end portion configured as an eyelet (17, 18, 19), and The induction plate (12) and the supporting elements (13, 14, 15, 16) are integrally formed from a single rectangular metal plate and are freely cut in the diagonal direction of the metal plate, so that an approximately four-leaf clover-shaped induction plate (12) is retained between the strip-shaped supporting elements (13, 14, 15, 16), and the induction plate has four pairs of induction blades (12a) facing each other.

2. The electronic multi-channel force sensor according to claim 1, characterized in that: The distal ends of at least two of the support elements (13, 14) form screw-on holes.

3. The electronic multi-channel force sensor according to claim 1, characterized in that: The end portion of at least one of the support elements (15, 16) forms a centering eyelet.

4. The electronic multi-channel force sensor according to claim 2, characterized in that: The screwing hole (17) is screwed to the printed circuit board (20).

5. The electronic multi-channel force sensor according to claim 3, characterized in that: The centering holes (18, 19) cooperate with the centering pins on the printed circuit board (20).

6. The electronic multi-channel force sensor according to claim 3, characterized in that: The centering eyelet is formed as an elongated hole (19).

7. The electronic multi-channel force sensor according to claim 1, characterized in that: The printed circuit board (20) has a plurality of conductor surfaces (21) and a deflection of the sensor plate (12) relative to the conductor surfaces (21) of the printed circuit board (20) can be detected by means of capacitance measuring electronics.

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