Force sensor connecting structure and force sensor

Abstract

The utility model relates to the technical field of force sensors, in particular to a force sensor connecting structure and a force sensor, the force sensor connecting structure comprises an elastic main body, the elastic main body is provided with a strain beam extending outwards, and the strain beam is fixed to an external structure. The strain beam deforms along with the elastic main body when the elastic main body is subjected to external force; the strain gauges are attached to at least one side face of the strain beam and used for detecting deformation of the strain beam in at least one axial direction, and the strain gauges are electrically connected to form a Wheatstone bridge; one end of the flexible circuit board assembly is electrically connected with the strain gauge, the other end of the flexible circuit board assembly is electrically connected with a circuit board, and the circuit board is used for signal conversion and output. Through the above arrangement, on one hand, the disorder of the wire harnesses is reduced, and on the other hand, the connection efficiency is also improved through the connection of the flexible circuit board, so that the production efficiency is improved.

Description

Technical Field

[0001] This utility model relates to the field of force sensor technology, and in particular to a force sensor connection structure and a force sensor. Background Technology

[0002] Force sensors are electronic devices capable of detecting and measuring externally applied forces, and are widely used in industrial automation, robotics, and other fields. These include resistance strain gauge force sensors, which typically consist of a metal strain gauge adhered to the surface of an elastic body. When the elastic body deforms under force, the strain gauge expands and contracts accordingly, causing a change in its resistance. These changes are converted into electrical signals by a Wheatstone bridge circuit, and after amplification, filtering, and analog-to-digital conversion, the final measured values ​​of force and torque are obtained.

[0003] In the prior art, such as the Chinese utility model patent with publication number CN216050389U disclosed on March 15, 2022, a single-axis force sensor is provided. It is constructed by attaching resistance strain gauges to the root positions of the upper and lower surfaces of the four strain beams of the elastic body, then electrically connecting the resistance strain gauges through a wire harness to form a Wheatstone bridge, and then connecting the wire harness to the circuit board to form the power supply and output lines.

[0004] However, in the actual production of the aforementioned force sensors, the large number of wire harnesses leads to a messy and disorganized wiring harness. Workers need to undergo a long period of on-the-job training to achieve correct welding, which reduces the production efficiency and yield of the products. Utility Model Content

[0005] In view of at least one of the above technical problems, the present invention provides a force sensor connection structure and a force sensor, and adopts structural improvements to improve product production efficiency and reduce wiring complexity.

[0006] According to a first aspect of the present invention, a force sensor connection structure is provided, comprising:

[0007] An elastic body has an outwardly extending strain beam, which is fixed to an external structure and deforms along with the elastic body when the elastic body is subjected to an external force.

[0008] Strain gauges are attached to at least one side of the strain beam to detect the deformation of the strain beam in at least one axial direction. The strain gauges are electrically connected to form a Wheatstone bridge.

[0009] A flexible circuit board assembly, one end of which is electrically connected to the strain gauge and the other end of which is electrically connected to a circuit board, the circuit board being used for signal conversion and output.

[0010] Furthermore, the strain beams are arranged at uniform intervals around the elastic body, and the number of flexible circuit board assemblies is the same as the number of strain beams and their positions are correspondingly arranged.

[0011] Furthermore, the strain beams are three or four in number, and the cross-section of the strain beams is rectangular.

[0012] Furthermore, the strain gauge is attached to one end of the strain beam near the elastic body.

[0013] Furthermore, the strain gauges are attached to the upper and lower surfaces and / or left and right sides of the strain beam.

[0014] Furthermore, multiple strain gauges are disposed on the surface of the strain beam, and the multiple strain gauges are arranged in a parallel or stacked manner.

[0015] Furthermore, the flexible circuit board assembly includes a first end for electrical connection with the circuit board, a second end for electrical connection with the strain gauge, and a connecting strip connecting the two, wherein the second end integrates a bridging circuit for bridging with the strain gauge.

[0016] Furthermore, the flexible circuit board assembly also includes an extension end disposed on at least one side of the second end, the extension end being used for electrical connection with the strain gauge on the side and / or bottom surface of the strain beam.

[0017] Furthermore, the second end and the extension end are electrically connected to the strain gauge by welding or conductive adhesive.

[0018] The first end is connected to the circuit board using a ZIF connector or by soldering.

[0019] According to a second aspect of the present invention, a force sensor is also provided, comprising a force sensor connection structure as described in any one of the first aspects, wherein the force sensor is a single-axis force sensor, a dual-axis force sensor, a triaxial force sensor, or a six-axis force sensor.

[0020] The beneficial effects of this utility model are as follows: This utility model replaces the existing connecting wire harness with a flexible circuit board assembly. Compared with the prior art, it reduces the messiness of the wire harness and improves the connection efficiency by using a flexible circuit board, thereby improving production efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the force sensor connection structure in an embodiment of the present invention;

[0023] Figure 2 This is an exploded disassembly diagram of the force sensor connection structure in an embodiment of this utility model;

[0024] Figure 3 This is a schematic diagram of the strain gauges connected in parallel in an embodiment of this utility model;

[0025] Figure 4 This is a schematic diagram of the strain gauge stacked arrangement in an embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the unfolded structure of the flexible circuit board assembly in an embodiment of this utility model;

[0027] Figure 6 This is a three-dimensional structural diagram of the flexible circuit board assembly after connection in an embodiment of this utility model;

[0028] Figure 7 This is a schematic diagram of the connection structure between the flexible circuit board assembly, the circuit board, and the strain gauge in an embodiment of this utility model.

[0029] Explanation of reference numerals in the attached drawings: 1. Elastic body; 11. Strain beam; 2. Strain gauge; 3. Flexible circuit board assembly; 31. First end; 32. Second end; 33. Connecting strip; 34. Bridge; 35. Extension end. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0031] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] like Figures 1 to 6 The force sensor connection structure shown includes an elastic body 1, a strain gauge 2, and a flexible circuit board assembly 3. Please refer to [reference needed] for details. Figure 2 In an embodiment of this invention, the elastic body 1 has an outwardly extending strain beam 11, which is fixed to an external structure and deforms along with the elastic body 1 when subjected to external force. A strain gauge 2 is attached to at least one side of the strain beam 11 to detect deformation of the strain beam 11 in at least one axial direction. The strain gauge 2 forms a Wheatstone bridge through electrical connections. One end of the flexible circuit board assembly 3 is electrically connected to the strain gauge 2, and the other end is electrically connected to a circuit board used for signal conversion and output. It should be noted that in an embodiment of this invention, the flexible circuit board assembly can be an FPC (flexible printed circuit) or a wire harness connected in parallel, such as multiple wires arranged in parallel and fixed together. Both have the advantages of flexibility, bendability, and reduced space occupation due to parallel connection. In the following embodiments of this invention, an FPC will be used as an example for detailed description. In the embodiments of this utility model, the specific structure of the elastic body 1 is not limited. It can be a single cantilever structure, a cross-shaped structure, etc. After the elastic body 1 is deformed by an external force, the strain beam 11 deforms along with the elastic body 1, thereby causing the strain gauge 2 to be subjected to force and generate strain, which in turn causes a change in its resistance. The resistance change is converted into a voltage output through a Wheatstone bridge, and finally, the magnitude of the force on the object is obtained through processing and analysis. The Wheatstone bridge is a resistance measurement circuit that uses the balance of the bridge circuit 34 to detect small resistance changes. It is existing technology, and those skilled in the art can choose between a half-bridge or a full-bridge as needed, which will not be elaborated here.

[0034] In the embodiments of this utility model, the existing connecting wire harness is replaced by a flexible circuit board assembly 3. Compared with the prior art, this reduces the messiness of the wire harness and improves the connection efficiency by using a flexible circuit board, thereby improving production efficiency.

[0035] Optionally, such as Figure 2As shown, strain beams 11 are arranged at uniform intervals around the elastic body 1, and the number of flexible circuit board assemblies 3 is the same as the number of strain beams 11, with corresponding positions. The uniform distribution of the strain beams 11 improves measurement accuracy. Furthermore, by ensuring that the number of flexible circuit board assemblies 3 is the same as the number of strain beams 11 and that they are correspondingly arranged, a one-to-one correspondence is achieved between the flexible circuit board assemblies 3 and the strain beams 11. This structural arrangement allows each strain beam 11 to have an independent signal acquisition channel and also facilitates installation and manufacturing.

[0036] Alternatively, please continue to refer to Figure 2 In some embodiments of this invention, there are three or four strain beams 11, and the cross-section of the strain beams 11 is rectangular. The use of three or four strain beams 11 and the rectangular cross-section structure allows for the application of triaxial or hexaaxial force sensors. Furthermore, in embodiments of this invention, the strain gauge 2 is attached to the end of the strain beam 11 near the elastic body 1. By attaching the strain gauge 2 to the side near the elastic body 1, the measurement sensitivity can be improved.

[0037] Optionally, in some embodiments of this utility model, the strain gauge 2 can be attached to the upper and lower surfaces, the left and right surfaces, or all four sides, to detect different axial forces. When specifically attaching the strain gauge 2, such as... Figure 3 As shown, multiple strain gauges can be attached side-by-side on each sidewall. It should be noted that when multiple strain gauges 2 are installed on the sidewalls, a method such as... Figure 4 The multiple strain gauges 2 shown are arranged in a stacked manner. By increasing the number of strain gauges 2, the signal redundancy and measurement accuracy of the sensor can be improved.

[0038] In some embodiments of this utility model, the specific structure of the flexible circuit board assembly 3 is as follows: Figure 5 and Figure 6 As shown, the flexible circuit board assembly 3 includes a first end 31 for electrical connection to the circuit board, a second end 32 for electrical connection to the strain gauge 2, and a connecting strip 33 connecting the two. The second end 32 integrates a bridge circuit 34 for bridging with the strain gauge 2. By integrating the bridge circuit 34 into the flexible circuit board assembly 3, additional wiring and soldering can be reduced, thereby further simplifying the circuit layout and improving product yield and manufacturing efficiency. It should be noted that in embodiments of this invention, the specific bridge circuit 34 can be selected in various ways, such as a full-bridge or half-bridge structure.

[0039] Please continue to refer to Figure 5 and Figure 6In some embodiments of this invention, the flexible circuit board assembly 3 further includes an extension end 35, which is disposed on at least one side of the second end 32. The extension end 35 is used for electrical connection with the strain gauge 2 on the side and / or bottom surface of the strain beam 11. In some embodiments of this invention, to accommodate six-axis measurement, the extension end 35 extends in a direction perpendicular to the connecting strip 33. It can extend on both sides or only on one side, as those skilled in the art can choose according to their needs. By setting the extension end 35, the extension end 35 and the second end 32 together wrap around the strain beam 11, thereby achieving the electrical connection of the strain gauge 2 in different directions. The extension end 35 is attached to the side wall of the strain beam 11. For the structure after connection with the strain gauge 2, please refer to [reference needed]. Figure 7 .

[0040] In embodiments of this invention, electrical connections can take various forms. For example, the second end 32 and the extension end 35 can be electrically connected to the strain gauge 2 by welding or using conductive adhesive. Specifically, welding can be performed using laser welding or ultrasonic micro-welding, while conductive adhesive can be applied using conductive silver paste printing. During welding, conductive silver paste is first applied to the flexible circuit board assembly 3 using a screen printing process, allowing it to directly bond and conduct to the metal leads of the strain gauge 2. In embodiments of this invention, the first end 31 is connected to the circuit board using a ZIF connector or by welding. The specific welding method is the same as described above. When using a ZIF connector, the end of the flexible circuit board assembly 3 has metallized pins, which are directly inserted into the ZIF connector and then clamped together to form a reliable connection. The ZIF connector connection method enables a detachable structure, facilitating future maintenance.

[0041] In embodiments of this utility model, a force sensor is also provided, including the force sensor connection structure described above. The force sensor is a single-axis force sensor, a dual-axis force sensor, a triaxial force sensor, or a six-axis force sensor. In embodiments of this utility model, a single-axis force sensor measures force in only one direction and is typically used for weighing or pressure measurement, often employing a cantilever beam or diaphragm structure. A dual-axis force sensor can simultaneously measure force in two orthogonal directions, often employing orthogonal cantilever beams, cross beams, etc. In specific configurations, two strain gauge bridges can be configured in each direction to decouple the forces in the two axes. A triaxial force sensor can simultaneously measure force in three directions for three-dimensional force sensing, often employing a ring beam, cross beam, etc., with at least four strain gauges configured in each axis to form an independent Wheatstone bridge. A six-axis force sensor can simultaneously measure force in the XYZ directions and torque in all three directions, typically employing a ring beam structure, with at least multiple strain gauge bridges configured in each direction, and force decoupling is achieved using a mathematical model. The above-mentioned structural forms are existing technologies, but all those that apply the force sensor connection structure of this utility model fall within the protection scope of this utility model.

[0042] Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A force sensor connection structure, characterized in that, include: An elastic body has an outwardly extending strain beam, which is fixed to an external structure and deforms along with the elastic body when the elastic body is subjected to an external force. Strain gauges are attached to at least one side of the strain beam to detect the deformation of the strain beam in at least one axial direction. The strain gauges are electrically connected to form a Wheatstone bridge. A flexible circuit board assembly, one end of which is electrically connected to the strain gauge and the other end of which is electrically connected to a circuit board, the circuit board being used for signal conversion and output.

2. The force sensor connection structure according to claim 1, characterized in that, The strain beams are arranged at uniform intervals around the elastic body, and the number of flexible circuit board assemblies is the same as the number of strain beams and their positions are correspondingly arranged.

3. The force sensor connection structure according to claim 2, characterized in that, The strain beams are three or four in number, and the cross-section of the strain beams is rectangular.

4. The force sensor connection structure according to claim 1, characterized in that, The strain gauge is attached to one end of the strain beam near the elastic body.

5. The force sensor connection structure according to claim 1, characterized in that, The strain gauges are attached to the upper and lower surfaces and / or left and right sides of the strain beam.

6. The force sensor connection structure according to claim 1, characterized in that, Multiple strain gauges are disposed on the surface of the strain beam, and the multiple strain gauges are arranged in a parallel or stacked manner.

7. The force sensor connection structure according to claim 1, characterized in that, The flexible circuit board assembly includes a first end for electrical connection to the circuit board, a second end for electrical connection to the strain gauge, and a connecting strip connecting the two. The second end integrates a bridge circuit for connecting the strain gauge to form the Wheatstone bridge.

8. The force sensor connection structure according to claim 7, characterized in that, The flexible circuit board assembly further includes an extension end disposed on at least one side of the second end, the extension end being used for electrical connection with the strain gauge on the side and / or bottom surface of the strain beam.

9. The force sensor connection structure according to claim 8, characterized in that, The second end and the extension end are electrically connected to the strain gauge by welding or conductive adhesive. The first end is connected to the circuit board using a ZIF connector or by soldering.

10. A force sensor, characterized in that, The force sensor connection structure includes any one of claims 1 to 9, wherein the force sensor is a single-axis force sensor, a dual-axis force sensor, a triaxial force sensor, or a six-axis force sensor.

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