Dual component common mode decoupled torque sensor elastomer and sensor

Abstract

The present application relates to the field of torque detection, in particular to a dual-component common body decoupling torque sensor elastic body and a sensor thereof. The dual-component common body decoupling torque sensor elastic body comprises: an inner ring structure; an outer ring structure surrounding the outer ring of the inner ring structure through a gap; four cross beams uniformly distributed along the circumference of the gap, each cross beam extending along the radial direction of the inner ring structure, one end of each cross beam being connected to the outer wall of the inner ring structure, and the other end of each cross beam being connected to the inner wall of the outer ring structure; wherein each cross beam is provided with two split holes spaced apart along the axial direction of the inner ring structure, and the two split holes separate the cross beam into two measurement beams located on the side away from the two split holes along the axial direction. The present application can convert the torque measurement from shear strain to bending normal strain to avoid 45° patches, offset axial force interference through bridge assembly, and make the strain distribution tend to be uniform to reduce the influence of patch position error on sensitivity.

Description

Technical Field

[0001] This invention relates to the field of torque detection, and more specifically to a dual-component cohesive torque sensor elastomer and its sensor. Background Technology

[0002] Currently, most torque sensors on the market use solid or hollow torsion shafts as elastomers, with metal foil strain gauges attached to the surface of the torsion shaft. Torque is detected by measuring shear strain in the ±45° direction.

[0003] The common elastomer structure of disc or spoke-type torque sensors consists of four rectangular cross-section straight beams evenly distributed circumferentially between the inner and outer rings. These beams are solid (although grooves or holes can be made on them, this structure is only used to adjust sensitivity and range and does not change the solid, load-bearing nature of the beam). When the inner and outer rings undergo relative torsion, the beams are subjected to a combination of bending moment and shear force. Consider a unit cell on the upper surface of the beam, whose principal stress direction forms a 45° angle with the beam axis. The maximum shear strain occurs in the 45° direction, as shown below. Figure 3 As shown in (a). Therefore, strain gauges need to be attached to the front or side of each beam at a 45° angle to the axis and assembled into a Wheatstone bridge to achieve torque measurement.

[0004] However, the torque sensor elastomer with the above-described structure, and even the torque sensor containing it, has the following technical problems: First, 45° patch placement is extremely sensitive to angular accuracy. Manual placement introduces angular deviations, which can easily lead to bending strain interference, causing the torque output signal to couple with the axial force or bending moment. Although MSG silicon strain gauges can be fabricated in a 45° sensitive direction, in the glass micro-melt screen printing process, accurately aligning the 45° direction and ensuring batch consistency is far more difficult and costly than aligning in the 0° / 90° direction.

[0005] Second, axial force cannot be naturally decoupled. When an elastic body is subjected to axial tensile or compressive loads, uniform tensile and compressive strains are generated on the beam. This strain is superimposed on the 45° shear strain caused by torque, making signal separation difficult. Existing technologies require the addition of an axial force sensor or rely on algorithms for decoupling, but the superposition of shear strain and axial tensile and compressive strains makes decoupling extremely difficult.

[0006] Third, the strain gradient is large. The bending strain in the beam root region changes abruptly along the beam's length, and even a small deviation in the strain gauge placement can lead to differences in sensitivity. For example... Figure 1 As shown, the strain at the beam root varies drastically along the beam length, and strain gauges are usually placed in the region near the root. Therefore, even a small error in the placement of the gauges can have a significant impact on the measurement results.

[0007] Therefore, there is an urgent need to provide a torque sensor elastomer and a torque sensor containing the above-mentioned technical problems. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a dual-component cohesive torque sensor elastomer, which can avoid 45° patch by converting torque measurement from shear strain to bending normal strain, and cancel axial force interference by bridging, and reduce the influence of patch position error on sensitivity by making the strain distribution more uniform.

[0009] To solve the above-mentioned technical problems, the technical solution of the present invention is: a dual-component cohesive decoupled torque sensor elastomer, comprising: Inner ring structure; The outer ring structure surrounds the outer ring of the inner ring structure with a gap between them; Four crossbeams are evenly distributed circumferentially along the gap, each crossbeam along the inner circle. The structure extends radially, with one end connected to the outer wall of the inner ring structure and the other end connected to the inner wall of the outer ring structure; wherein, Each crossbeam is provided with two dividing holes spaced apart along the axial direction of the inner ring structure. The two dividing holes divide the crossbeam along the axial direction into two measuring beams located on opposite sides of the two dividing holes.

[0010] Furthermore, the dividing hole extends through the crossbeam along its width direction.

[0011] Furthermore, the dividing hole is an oblong hole extending along the length direction of the crossbeam.

[0012] Furthermore, each of the dividing holes has a gap between its two ends and the two ends of the crossbeam to which it is located.

[0013] Furthermore, the inner ring structure, the outer ring structure, and the four crossbeams are integrally formed.

[0014] The present invention also relates to a sensor comprising at least one silicon-based strain gauge assembly and the dual-component coherent decoupled torque sensor elastomer, wherein each silicon-based strain gauge assembly comprises four silicon-based strain gauges forming a Wheatstone bridge. Specifically, for each group of four silicon-based strain gauges: two silicon-based strain gauges are disposed on the surfaces of two measuring beams that are circumferentially spaced 180° apart and located in the same axial plane; two silicon-based strain gauges on the same measuring beam are spaced apart along the width direction of the measuring beam and extend along the length direction of the measuring beam; all four silicon-based strain gauges are located at the inner end of the measuring beam or at the outer end of the measuring beam.

[0015] Furthermore, the silicon-based strain gauge is sintered onto the surface of the measuring beam via glass micro-fuse screen printing.

[0016] Furthermore, the sensor also includes: The first sealing structure seals one side of the gap and together with the dual-component co-decoupled torque sensor elastomer forms a circuit board mounting cavity. A second sealing structure seals the other side of the gap; A circuit board is installed inside the circuit board mounting cavity and is electrically connected to the silicon-based strain gauge.

[0017] By adopting the above technical solution, the present invention has the following beneficial effects: (1) This invention divides the crossbeam into two measuring beams located on opposite sides of the two dividing holes, making the crossbeam a parallelogram structure. When the inner ring twists relative to the outer ring, the two measuring beams are forced to bend in an S-shape, with the strain direction along the extension direction of the measuring beam (i.e., the 0° direction), rather than the 45° direction in the traditional structure. The stress magnitude is linearly related to the torque. Therefore, the strain gauges installed on the surface of the measuring beam only need to be arranged along the 0° direction, avoiding the angle accuracy requirement of 45° patching, reducing the difficulty of patching process, and this direction matches the most sensitive direction of MSG silicon strain gauges, which is beneficial for mass screen printing. At the same time, the surface of the measuring beam is a planar structure, which is conducive to the batch printing of multiple silicon-based strain gauges at one time using glass micro-melt screen printing process, and the process consistency and production efficiency are better than the traditional manual pasting method; (2) Under the action of torque, the upper or lower measuring beams located on the same crossbeam will generate strain regions with equal strain magnitude and opposite signs; under the action of axial force, the inner or outer ends of the four measuring beams located on the same axial plane will generate tensile or compressive strain in the same direction. Based on this strain response, by setting four silicon-based strain gauges on the inner or outer end surfaces of two measuring beams located on the same axial plane and 180° apart, forming a Wheatstone bridge connection, the axial force signals cancel each other out at the output end of the torque bridge circuit, the output of the coupled axial force bridge is zero, and the torque signal is unaffected, thereby realizing the physical separation of torque and axial force on a single elastic body without the need for additional axial force sensors or algorithm-based decoupling; (3) The double-hole parallel beam structure makes the bending moment at the end of the measuring beam basically constant and the strain gradient small. The bending strain area covers a certain range at the end of the measuring beam rather than being concentrated at a certain point, which reduces the influence of the strain gauge installation position deviation on the sensitivity. Attached Figure Description

[0018] Figure 1 The strain finite element simulation cloud diagram of the elastic body of a traditional torque sensor under stress. Figure 2This is a schematic diagram of the structure of the elastomer of the dual-component cohesive decoupled torque sensor of the present invention; Figure 3 This is a schematic diagram showing the strain of a beam of a traditional torque sensor elastomer and the dual-component decoupled torque sensor elastomer of the present invention under stress. Figure 4 The strain finite element simulation cloud diagrams of the elastomer of the dual-component cohesive decoupled torque sensor of the present invention under torque and axial force respectively; Figure 5 This is a schematic diagram showing the patch position of the elastomer of the dual-component cohesive decoupled torque sensor of the present invention; Figure 6 A schematic diagram of a structure in which two silicon-based strain gauge groups are mounted on the elastomer of a dual-component coherent decoupled torque sensor. Figure 7 This is a schematic diagram of the sensor structure of the present invention; Figure 8 This is a cross-sectional view of the sensor of the present invention; Figure 2 , Figure 6 , Figure 7 and Figure 8 In the middle: 1. Inner ring structure; 2. Outer ring structure; 3. Gap; 4. Crossbeam; 5. Dividing hole; 6. Measuring beam; 7. Silicon-based strain gauge; 8. First sealing structure; 9. Second sealing structure; 10. Circuit board; Figure 1 , Figure 3 , Figure 4 and Figure 5 In the middle: different colors represent the strain state and strain value of different parts of the elastomer, where the red area represents compressive stress, the blue area represents tensile stress, and the darker the color, the greater the stress value. Figure 3 (a) is a top view of the strain of the elastic beam of a conventional torque sensor under stress; (b) is a longitudinal section view of the strain of the elastic beam of the present invention under stress. Figure 4 In the middle: (a) is the finite element simulation cloud diagram of the elastic body of the present invention under torque, and (b) is the finite element simulation cloud diagram of the elastic body of the present invention under axial force. Detailed Implementation

[0019] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0020] like Figure 2 As shown, a dual-component cohesive decoupled torque sensor elastomer includes: Inner ring structure 1; The outer ring structure 2 surrounds the outer ring of the inner ring structure 1 with a gap 3; Four crossbeams 4 are evenly distributed circumferentially along the gap 3. Each crossbeam 4 extends radially along the inner ring structure 1, with one end connected to the outer wall of the inner ring structure 1 and the other end connected to the inner wall of the outer ring structure 2; wherein, Each crossbeam 4 is provided with two dividing holes 5 arranged at intervals along the axial direction of the inner ring structure 1. The two dividing holes 5 divide the crossbeam 4 into two measuring beams 6 located on opposite sides of the two dividing holes 5 along the axial direction.

[0021] In this embodiment, the crossbeam 4 is divided into two measuring beams 6 located on opposite sides of the two dividing holes 5 by two dividing holes 5. When the inner ring structure 1 and the outer ring structure 2 undergo relative torsion, the two measuring beams 6 produce S-shaped bending deformation. The direction of the normal strain on their surfaces is along the extension direction of the measuring beams 6 (i.e., the radial direction of the inner ring structure 1, 0° direction), rather than the 45° direction in the traditional structure. Specifically, as shown below... Figure 3 As shown in (b). This allows the strain gauges mounted on the surface of the measuring beam 6 to be arranged only along the 0° direction, avoiding the 45° angle accuracy requirement for the gauges and reducing the difficulty of the gauge mounting process.

[0022] Under the action of torque, the upper and lower measuring beams 6 located on the same crossbeam 4 bend and deform, and strain regions with equal magnitude but opposite signs are generated on both the upper and lower measuring beams 6, as shown in the following figures. Figure 3 As shown in (b) and Figure 4 As shown in (a). Taking the upper measuring beam 6 as an example, the strains on both sides of its inner end surface are equal in magnitude but opposite in sign, and the strains on both sides of its outer end surface are also equal in magnitude but opposite in sign. The same applies to the lower measuring beam 6, and at the position corresponding to the upper measuring beam 6 in the axial direction of the inner ring structure 1, the strain magnitude is equal to that of the upper measuring beam 6 but opposite in sign.

[0023] Under axial force, the inner or outer ends of all four crossbeams will produce the same tensile or compressive strain, specifically as follows: Figure 4 As shown in (b) above. Specifically, the four upper measuring beams 6 produce the same tensile or compressive strain at their inner ends within the width range, and the four upper measuring beams 6 produce another strain at their outer ends within the width range, which is the same in value but in a different direction from the strain at the inner ends. Figure 4 As shown in (b), tensile strain is generated at the inner end and compressive strain is generated at the outer end. The specific type of strain depends on the direction of the axial force.

[0024] Based on the above differences in strain response, it is possible to Figure 5A torque measurement bridge is constructed using silicon-based strain gauges 7 at the indicated locations: two measuring beams 6 are circumferentially spaced 180° apart and located in the same axial plane, with each silicon-based strain gauge 7 located either on the inner end surface or on the outer end surface of the corresponding measuring beam 6, for a total of four silicon-based strain gauges (e.g., ...). Figure 5 The red sections form one full-bridge circuit, and the purple sections form another. When measuring torque, the average value of the two full-bridge circuits is taken. When the elastic body is subjected to torque, the bridge outputs an electrical signal corresponding to the torque. If, during torque measurement, the elastic body is subjected to an additional axial force (for torque sensors, because the inner and outer rings are fixed, most torque sensors on the market are affected by axial force to varying degrees), the four strain gauges respond to the axial force by producing tensile or compressive strains of the same direction and equal value, satisfying R1×R3-R2×R4=0, resulting in a zero bridge output. Therefore, the axial force cannot be coupled into the torque measurement. Thus, the physical separation of torque and axial force (i.e., decoupling the coupled axial force) can be achieved on a single elastic body without the need for an additional axial force sensor or a decoupling algorithm.

[0025] It should be noted that currently, torque sensors are mostly equipped with fixed inner and outer rings, so the majority of interference they experience is from axial forces. This embodiment effectively decouples the coupled axial force. R1, R2, R3, and R4 correspond to... Figure 5 The resistance of the four red silicon-based strain gauges 7 also corresponds to Figure 5 The resistance of the four purple silicon-based strain gauges 7.

[0026] Furthermore, the double-hole parallel beam structure ensures that the bending moment at the end region of the measuring beam 6 remains essentially constant, resulting in a small strain gradient. The bending strain region covers a certain area at the end of the measuring beam 6 rather than being concentrated at a single point. Specifically, as shown below... Figure 3 As shown in (b), the impact of strain gauge installation position deviation on sensitivity is reduced. Furthermore, the planar surface of the measuring beam 6 facilitates the batch printing of multiple silicon-based strain gauges using glass micro-fusion screen printing technology, resulting in superior process consistency and production efficiency compared to traditional manual pasting methods.

[0027] In some examples, such as Figure 2 and Figure 6 As shown, the dividing hole 5 extends through the crossbeam 4 along the width direction of the crossbeam 4.

[0028] In some examples, such as Figure 2 and Figure 6 As shown, the dividing hole 5 is an oblong hole extending along the length direction of the crossbeam 4.

[0029] In some examples, such as Figure 2 and Figure 6 As shown, each of the dividing holes 5 has a gap between its two ends and the two ends of the crossbeam 4 to which it is located.

[0030] In some examples, such as Figure 2 and Figure 6 As shown, the inner ring structure 1, the outer ring structure 2, and the four crossbeams 4 are integrally formed structures.

[0031] like Figure 7 and Figure 8 As shown, a sensor includes at least one silicon-based strain gauge group and a dual-component co-existing decoupled torque sensor elastomer as described in any of the above examples, each silicon-based strain gauge group including four silicon-based strain gauges 7 forming a Wheatstone bridge. Specifically, for each silicon-based strain gauge group, two silicon-based strain gauges 7 are disposed on the surfaces of two measuring beams 6 that are circumferentially spaced 180° apart and located in the same axial plane; the two silicon-based strain gauges 7 on the same measuring beam 6 are spaced apart along the width direction of the measuring beam 6 and extend along the length direction of the measuring beam 6; all four silicon-based strain gauges 7 are located at the inner end of the measuring beam 6 or at the outer end of the measuring beam 6.

[0032] When at least two silicon-based strain gauge sets are set, the average output can be taken to improve measurement reliability, or one can be used as the main strain gauge while the others are used as redundant backups.

[0033] In some examples, the silicon-based strain gauge 7 is sintered onto the surface of the measuring beam 6 via glass micro-fuse screen printing. Specifically, the silicon-based strain gauge 7 is printed onto the planar surface of the measuring beam 6 using a glass micro-fuse screen printing process, and then sintered at high temperature to form an integrated encapsulation structure with the measuring beam 6.

[0034] In some examples, such as Figure 7 and Figure 8 As shown, the sensor also includes: The first sealing structure 8 seals one side of the gap 3 and together with the dual-component co-existing decoupled torque sensor elastomer, forms a circuit board mounting cavity. The second sealing structure 9 seals the other side of the gap 3; Circuit board 10 is installed in the circuit board mounting cavity and is electrically connected to the silicon-based strain gauge 7.

[0035] The first sealing structure 8 and the second sealing structure 9 can be sealing sheets, which together ensure the sealing of the circuit board mounting cavity.

[0036] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A dual-component cohesive decoupled torque sensor elastomer, characterized in that, include: Inner ring structure (1); The outer ring structure (2) surrounds the outer ring of the inner ring structure (1) with a gap (3); Four crossbeams (4) are evenly distributed circumferentially along the gap (3), each crossbeam (4) extending radially along the inner ring structure (1), one end connected to the outer wall of the inner ring structure (1), and the other end connected to the inner wall of the outer ring structure (2); wherein, Each crossbeam (4) is provided with two dividing holes (5) arranged axially along the inner ring structure (1), the two dividing holes (5) dividing the crossbeam (4) into two measuring beams (6) located on opposite sides of the two dividing holes (5).

2. The dual-component cohesive decoupled torque sensor elastomer according to claim 1, characterized in that, The dividing hole (5) extends through the crossbeam (4) along the width direction of the crossbeam (4).

3. The dual-component cohesive decoupled torque sensor elastomer according to claim 1, characterized in that, The dividing hole (5) is a waist-shaped hole extending along the length direction of the crossbeam (4).

4. The dual-component cohesive decoupled torque sensor elastomer according to claim 3, characterized in that, Each of the dividing holes (5) has a gap between its two ends and the two ends of the crossbeam (4) to which it is located.

5. The dual-component cohesive decoupled torque sensor elastomer according to claim 1, characterized in that, The inner ring structure (1), the outer ring structure (2), and the four crossbeams (4) are integrally formed.

6. A sensor, characterized in that, It includes at least one silicon-based strain gauge group and a dual-component co-decoupled torque sensor elastomer as described in any one of claims 1 to 5, wherein each silicon-based strain gauge group includes four silicon-based strain gauges (7) that form a Wheatstone bridge. For each group of four silicon strain gauges (7): two silicon strain gauges (7) are provided on the surfaces of two measuring beams (6) that are circumferentially spaced 180° apart and located in the same axial plane; the two silicon strain gauges (7) on the same measuring beam (6) are spaced apart along the width direction of the measuring beam (6) and extend along the length direction of the measuring beam (6); all four silicon strain gauges (7) are located at the inner end of the measuring beam (6) or at the outer end of the measuring beam (6).

7. The sensor according to claim 6, characterized in that, The silicon-based strain gauge (7) is sintered onto the surface of the measuring beam (6) by glass micro-fuse screen printing.

8. The sensor according to claim 6, characterized in that, Also includes: The first sealing structure (8) is sealed on one side of the gap (3) and together with the dual-component decoupled torque sensor elastomer, forms a circuit board mounting cavity. The second sealing structure (9) seals the other side of the gap (3); The circuit board (10) is installed in the circuit board mounting cavity and is electrically connected to the silicon-based strain gauge (7).

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