Positive v-shaped silicon strain gauge flexspline integrated glass micro-fuse torque sensor and manufacturing method

Abstract

This application discloses a V-shaped silicon strain gauge flexible wheel integrated with a glass micro-fused torque sensor and its manufacturing method. The sensor includes a flexible wheel; a sensing component is mounted on the flexible wheel; the sensing component includes a glass layer and a semiconductor silicon strain gauge; the glass layer is fused to the metal surface of the flexible wheel, and the semiconductor silicon strain gauge is embedded within the glass layer; a signal processing circuit board assembly is also included; the signal processing circuit board assembly is bonded to the flexible wheel with an oil-resistant adhesive and is electrically connected to the semiconductor silicon strain gauge. This application directly integrates a glass micro-fused torque sensor onto the flexible wheel of a harmonic reducer, without altering the structure of the harmonic reducer, enabling efficient and accurate measurement of load torque, achieving lightweight design, and effectively meeting the torque sensor requirements of robots. Unlike methods that bond foil strain gauges to the flexible wheel or use magnetron sputtering to form thin films, the glass micro-fused process in this application is simple and suitable for mass automated production.

Description

Technical Field

[0001] This application relates to the field of torque sensor technology, and in particular to a positive V-type silicon strain gauge flexible wheel integrated glass micro-fusion torque sensor and its manufacturing method. Background Technology

[0002] With the development of manufacturing and intelligentization, the demand for robots is constantly growing, with collaborative robots and embodied intelligent robots developing particularly rapidly. Faced with various complex and ever-changing application environments, robots are rapidly evolving towards higher intelligence and higher safety.

[0003] Therefore, equipping robots with high-performance and high-reliability torque sensors is fundamental to developing collaborative and embodied intelligent robots with efficient and accurate control performance and high safety performance. Through their sensing capabilities, the forces and torques of the joints can be monitored in real time, enabling accurate and coordinated movement control and ensuring safety. Currently, force or torque measurement is achieved by externally mounting torque sensors on the joints. However, this method alters the joint structure, increases its weight, introduces measurement lag, and also restricts the lightweight requirements of robots. Summary of the Invention

[0004] The purpose of this application is to provide a positive V-shaped silicon strain gauge flexible wheel integrated glass micro-melting torque sensor and a manufacturing method thereof, so as to at least solve one of the above-mentioned technical problems.

[0005] To achieve the above objectives, this application provides the following technical solution: In a first aspect, this application provides a positive V-type silicon strain gauge flexible wheel integrated glass micro-fused torque sensor, comprising: A flexible wheel; the flexible wheel is equipped with a sensing component; the sensing component includes a glass layer and a semiconductor silicon strain gauge; The glass layer is fused to the metal surface of the flexible wheel, and the semiconductor silicon strain gauge is embedded in the glass layer; A signal processing circuit board assembly; the signal processing circuit board assembly is bonded to the flexible wheel by an oil-resistant adhesive and is electrically connected to the semiconductor silicon strain gauge.

[0006] In a preferred embodiment, the semiconductor silicon strain gauge is a positive V-type silicon strain gauge; the flexible wheel includes a diaphragm, and the center of the semiconductor silicon strain gauge is offset from the median diameter circle of the diaphragm by at least 0.5 mm in the radial direction; the positive V-type silicon strain gauge integrates two mutually perpendicular resistance bars on the same chip using micro-electro-mechanical system (MEMS) technology, and the angular error between the two resistance bars is within ±0.1°; the symmetry line of the positive V-type silicon strain gauge is arranged along the radial direction of the flexible wheel, so that the two resistance bars are aligned with the principal stress directions of 45° and 135° on the surface of the diaphragm, respectively.

[0007] In a preferred embodiment, the glass layer is formed by local heating and sintering of glass adhesive at a temperature below 400°C; the local heating is laser local heating or aerogel insulation local heating, combined with a negative pressure system; the peak temperature of the local heating area is controlled below 380°C, and the heating duration does not exceed 5 seconds.

[0008] In a preferred embodiment, multiple sets of positive V-shaped silicon strain gauges are arranged at equal angular intervals along the circumference of the flexible wheel; the multiple sets of positive V-shaped silicon strain gauges are connected to form a Wheatstone bridge, and there are at least two sets.

[0009] In a preferred embodiment, two positive V-shaped silicon strain gauges are symmetrically arranged 180° apart along the circumference of the flexible wheel. The two resistance bars of each positive V-shaped silicon strain gauge are respectively connected to the adjacent arms of the Wheatstone bridge, and the four resistance bars form a full bridge.

[0010] In a preferred embodiment, the signal processing circuit board assembly is an epoxy resin printed circuit board, a flexible circuit board, or a rigid-flex board, and the surface pads of the signal processing circuit board assembly are gold-plated; the oil-resistant adhesive is a polyurethane adhesive, a fluorosilicone adhesive, or an epoxy resin adhesive; the signal processing circuit board assembly is electrically connected to the semiconductor silicon strain gauge via bonding leads; the semiconductor silicon strain gauge, the signal processing circuit board assembly, and the bonding leads are covered and protected by an oil-resistant soft protective adhesive.

[0011] In one preferred embodiment, the glass adhesive is formed on a flexible roller by screen printing, stencil printing, trajectory dispensing or spraying, and sintered at a temperature below 400°C.

[0012] In a preferred embodiment, the multiple sets of positive V-shaped silicon strain gauges are arranged in 2, 8, or 24 sets at equal angular intervals along the circumference of the flexible wheel.

[0013] Secondly, this application provides a method for manufacturing a V-shaped silicon strain gauge flexure integrated with a glass micro-fused torque sensor, comprising: roughening the sensor surface of the flexure; forming a glass body on the flexure; placing a semiconductor silicon strain gauge on the glass body and performing local heating sintering to fuse the semiconductor silicon strain gauge and the glass body into one piece; applying an oil-resistant adhesive to bond a signal processing circuit board assembly to the flexure; performing wire bonding to electrically connect the signal processing circuit board assembly to the semiconductor silicon strain gauge; and applying an oil-resistant soft protective adhesive.

[0014] Thirdly, this application provides a method for manufacturing a positive V-type silicon strain gauge, comprising: A P-type epitaxial layer is formed on a silicon wafer; A boron-rich region is photolithographically etched on the P-type epitaxial layer, and boron implantation is performed to form a P+ region; A resistive strip pattern is photolithographically etched on a P-type epitaxial layer containing the P+ region, and deep reactive ion etching is used to etch the P-type epitaxial layer to a predetermined depth to form two mutually perpendicular resistive strips. Silicon oxynitride is deposited on the etched resistor strip structure, and lead holes are formed by photolithography and etching. A metal layer is deposited at the lead hole, and an ohmic connection is formed by metallization. Photolithography and etching are performed on the metallized structure to form the shape of the positive V-strain gauge; The wafer is thinned and etched on the back side to release and form a single positive V-shaped silicon strain gauge.

[0015] Compared with the prior art, this application has at least one of the following technical effects: 1. This application integrates a glass micro-fusion torque sensor directly onto the flexible wheel of a harmonic reducer, achieving efficient and accurate measurement of load torque without altering the reducer's structure. This results in lightweight design and effectively meets the robot's torque sensor requirements. Unlike methods that involve bonding foil strain gauges to the flexible wheel or using magnetron sputtering to form thin films, the glass micro-fusion process in this application is simple and suitable for mass automated production. Furthermore, the output signal of the silicon strain gauge based on the semiconductor piezoresistive effect is significantly greater than that of foil strain gauges and sputtered thin-film strain gauges, resulting in a higher signal-to-noise ratio. Taking a four-arm full-bridge as an example, the sensitivity of the positive V-shaped semiconductor silicon strain gauge in this application embodiment can reach over 20mV / V, representing an improvement of approximately one order of magnitude.

[0016] 2. The positive V-shaped silicon strain gauge of this application integrates two mutually perpendicular resistance strips on the same chip using MEMS photolithography, and the angle error can be controlled within ±0.1°. After its symmetry line is set along the radius direction of the flexure, the two resistance strips automatically coincide with the 45° and 135° principal stress directions on the surface of the flexure diaphragm, fundamentally eliminating the alignment error caused by manual pasting of discrete strain gauges and realizing "self-alignment" in structure.

[0017] 3. The two resistors on the same chip in this application have high process and temperature consistency, with a temperature drift coefficient of less than 5ppm / ℃, while the temperature drift of discrete resistor half-bridge is usually as high as 50ppm / ℃. With the symmetrical double positive V-type full-bridge structure, two positive V-type silicon strain gauges are symmetrically arranged 180° apart along the circumference of the flexible wheel. When the flexible wheel is subjected to torque, the two chips feel tensile stress and compressive stress respectively, which doubles the bridge output. When subjected to radial or axial disturbance force, the strains generated by the two in the same direction cancel each other out in the bridge, effectively suppressing common mode error and realizing dual self-compensation for temperature and external interference.

[0018] 4. The glass layer of this application is formed by localized laser heating or aerogel insulation localized heating sintering of glass adhesive. The sintering temperature is below 400℃, and a negative pressure system is used to assist in exhausting the air, which avoids the damage to the properties of the flexible wheel matrix material caused by the high temperature of 500℃~600℃ of conventional glass micro-melting. The peak temperature of the local heating area is controlled within 380℃, and the heating duration does not exceed 5 seconds. After sintering, the hardness and fatigue life of the flexible wheel matrix change is less than 3%, ensuring that the mechanical properties obtained by the flexible wheel through precision heat treatment are not damaged.

[0019] 5. The signal processing circuit board assembly of this application is bonded to the flexible wheel with a low-hardness, low-modulus oil-resistant adhesive, so that the stress and strain generated by the deformation of the flexible wheel under force will not be transmitted to the circuit board through the adhesive layer; the semiconductor silicon strain gauge, circuit board assembly and bonding leads are covered and protected by oil-resistant soft protective adhesive, which can work stably for a long time in the lubricating oil environment of the reducer, ensuring the reliability of electrical connection and positional stability.

[0020] 6. This application supports the arrangement of multiple sets of positive V-type silicon strain gauges at equal angular intervals along the circumference of the flexible wheel. Through multiple independent full-bridge parallel outputs or averaging processing, the measurement redundancy and accuracy can be further improved, adapting to application scenarios with different accuracy levels and reliability requirements. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. 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 overall assembly of the torque sensor provided in an embodiment of this application; Figure 2 A schematic diagram of the arrangement of the flexible sintered silicon strain gauge provided in an embodiment of this application; Figure 3 This is a schematic diagram of the compressive and tensile stresses of a flexible wheel under torque, provided in an embodiment of this application. Figure 4 Circuit diagram of the Wheatstone bridge provided in the embodiments of this application Figure 1 ; Figure 5 Circuit diagram of the Wheatstone bridge provided in the embodiments of this application Figure 2 ; Figure 6 This is a schematic diagram of the structure of a half-bridge silicon strain gauge provided in an embodiment of this application; Figure 7 This is a schematic diagram of the structure of a single-resistance silicon strain gauge provided in an embodiment of this application; Figure 8 This is a schematic diagram of the structure of a positive V-type silicon strain gauge provided in an embodiment of this application; Figure 9 A schematic diagram of the arrangement of eight silicon strain gauges provided in an embodiment of this application; Figure 10 This is a schematic diagram of the packaging cross-section provided in an embodiment of this application; Figure 11 This is a schematic cross-sectional view of a positive V-type strain gauge provided in an embodiment of this application.

[0023] Figure label: 1. Flexible wheel; 2. Glass layer; 3. Semiconductor silicon strain gauge; 4. Signal processing circuit board assembly. Detailed Implementation

[0024] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0025] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0026] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0027] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0028] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0030] In this application, the term "positive V-type silicon strain gauge" refers to a semiconductor silicon strain gauge in which two mutually perpendicular resistance bars are integrated on the same chip using microelectromechanical systems (MEMS) technology. The two resistance bars are arranged in a "V" shape (figure-eight shape), and the line of symmetry is located in the direction of the angle bisector of the two resistance bars.

[0031] In this application, the term "mid-diameter circle" refers to the circle located on the midline between the outer and inner diameters of the annular region of the flexible diaphragm, and the diameter of the mid-diameter circle is half the sum of the outer and inner diameters of the flexible diaphragm.

[0032] Example 1

[0033] Figure 1 This application illustrates an embodiment of a positive V-type silicon strain gauge flexible wheel integrated glass micro-fusion torque sensor, comprising: Flexible wheel 1; a sensing component is provided on the flexible wheel 1; The sensing components include a glass layer 2 and a semiconductor silicon strain gauge 3; The glass layer 2 is fused to the metal surface of the flexible wheel 1, and the semiconductor silicon strain gauge 3 is embedded in the glass layer 2; Signal processing circuit board assembly 4; Signal processing circuit board assembly 4 is bonded to flexible wheel 1 with oil-resistant adhesive and electrically connected to semiconductor silicon strain gauge 3.

[0034] Specifically, the sensing components are integrated into the inner groove surface of the flange of the flexure 1 of the harmonic reducer.

[0035] like Figure 1 As shown, the sensing component includes a glass layer 2 bonded to the metal surface of the flexure 1 via a low-temperature glass micro-melting process, a semiconductor silicon strain gauge 3 embedded in the glass layer 2, an oil-resistant adhesive, a circuit board assembly, bonding leads, and an oil-resistant soft protective adhesive. The glass layer 2 is bonded to the metal portion of the flexure 1 via a glass adhesive sintering process, and the semiconductor silicon strain gauge 3 is deposited within the glass layer 2 via a glass micro-melting process. The glass layer is formed by localized heating and sintering of the glass adhesive. Under localized heating, the glass adhesive softens and flows, wetting the metal surface of the flexure and the semiconductor silicon strain gauge. The glass body and the oxide layer on the metal surface of the flexure are bonded together through chemical bonding (e.g., Si-O-M bonds) and micromechanical interlocking after the glass body has cured, thus firmly encapsulating and fixing the semiconductor silicon strain gauge to the metal surface of the flexure. This bonding method ensures the reliability of strain transmission under torque and avoids the creep and aging problems caused by organic adhesives.

[0036] Furthermore, the semiconductor silicon strain gauge 3 is a positive V-type silicon strain gauge; The flexible wheel 1 includes a diaphragm, and the center of the semiconductor silicon strain gauge 3 is offset from the median diameter circle of the diaphragm by at least 0.5 mm in the radial direction. The positive V-type silicon strain gauge integrates two mutually perpendicular resistance bars on the same chip using MEMS technology, with the angular error between the two resistance bars within ±0.1°; The symmetry line of the positive V-shaped silicon strain gauge is set along the radial direction of the flexible wheel 1, so that the two resistance bars are aligned with the principal stress directions at 45° and 135° on the diaphragm surface, respectively.

[0037] Specifically, such as Figure 2 and Figure 3 As shown, the semiconductor silicon strain gauge 3 is a positive V-type silicon strain gauge, which integrates two mutually perpendicular resistance bars on the same chip using MEMS technology. The positive V-type silicon strain gauge is fabricated using MEMS technology, with the two resistors of the strain gauge at 90°, and their line of symmetry placed on the radius line of the flexible wheel 1. One resistor represents compressive strain, and the other represents tensile strain.

[0038] The symmetry line of the positive V-shaped silicon strain gauge is set along the radial direction of the flexure 1, so that the two resistance bars are automatically aligned with the 45° and 135° principal stress directions on the diaphragm surface of the flexure 1, respectively, to measure the tensile and compressive stresses of the flexure 1. When the flexure 1 is subjected to torque, the principal stress directions generated on its diaphragm surface are 45° and 135°, respectively. Traditional solutions require manual attachment of two independent single resistance strain gauges along these two directions, with angular deviations typically reaching ±2°, and the positions of the two strain gauges cannot be completely coincident, leading to measurement errors. However, the positive V-shaped silicon strain gauge in this embodiment uses MEMS photolithography to integrate the two resistance bars onto the same chip, and the angular error can be controlled within ±0.1°. The two resistance bars are positioned together with the chip, and their positions are completely coincident, exhibiting a structural "self-alignment" characteristic.

[0039] Because silicon strain gauges have a high piezoresistive coefficient, the position where the silicon strain gauge and the glass sintering wheel 1 are bonded can effectively measure torque and effectively reduce the influence of the axial or three-dimensional deformation of the flexure wheel 1 on the deformation of the silicon strain gauge. To illustrate, taking a four-arm full-bridge strain gauge as an example, the signal sensitivity of a traditional foil strain gauge is about 2mV / V@1000με, and that of a magnetron sputtering thin film strain gauge is 3mV / V@1000με. However, the positive V-shaped semiconductor silicon strain gauge used in this embodiment can achieve a sensitivity of more than 20mV / V@1000με, which is about an order of magnitude higher and significantly improves the signal-to-noise ratio.

[0040] Preferably, the center of the semiconductor silicon strain gauge 3 is offset from the center diameter of the diaphragm of the flexible wheel 1 by more than 0.5 mm to avoid the nonlinear region at the edge of the diaphragm stress field and ensure that the strain gauge works in a region with a small stress gradient and good linearity.

[0041] In this embodiment, one resistor strip of the positive V-shaped silicon strain gauge bears compressive strain, while the other resistor strip bears tensile strain. The two resistors on the same chip have good process consistency and high temperature consistency, with a temperature drift coefficient of less than 5ppm / ℃, while the temperature drift of discrete resistor half-bridge is usually as high as 50ppm / ℃, thus achieving a good temperature self-compensation effect.

[0042] Furthermore, the glass layer 2 is formed by local heating and sintering of glass adhesive at a temperature below 400°C; Local heating is achieved through laser local heating or aerogel insulation local heating, combined with a negative pressure system; The peak temperature of the local heating area is controlled below 380℃, and the heating duration does not exceed 5 seconds.

[0043] Specifically, the sintering temperature of the low-temperature glass micro-melting process is below 400℃. Unlike ordinary glass micro-melting sensors that require a sintering temperature of 500℃ to 600℃, the glass adhesive used in this embodiment is a low-temperature type, which can be sintered at temperatures below 400℃ and can soften below 400℃ to bond with the semiconductor silicon strain gauge 3 without affecting the material structure properties of the flexible wheel 1.

[0044] Furthermore, the glass glue is formed on the flexible wheel 1 by screen printing, stencil printing, trajectory dispensing or spraying, and sintered at a temperature below 400°C.

[0045] Specifically, low-temperature silicone sealant can be formed on the flexible wheel 1 through methods such as screen printing, stencil printing, trajectory dispensing, and spraying.

[0046] Since the flexible wheel 1 cannot withstand a total temperature of 400℃, this embodiment uses a specialized sintering process and dedicated equipment for glass sintering. Unlike the overall heating method used for the sensor, this embodiment employs localized rapid heating via laser or localized heating with special aerogel insulation, and is equipped with a negative pressure system to heat only the area where the strain gauge is located, completing the sintering of the glass through micro-melting. The peak temperature of the localized heating area is controlled below 380℃, the diameter of the heating area is only 2-3 mm larger than the strain gauge size, the heating duration does not exceed 5 seconds, and negative pressure (e.g., -0.08 MPa) is used to assist in exhausting the air. After sintering, the changes in hardness and fatigue life of the flexible wheel 1 substrate are both less than 3%.

[0047] Specifically, aerogel insulation local heating refers to setting an aerogel insulation layer around the strain gauge location, exposing only the area to be heated, and using heat sources such as lasers for local heating, so that the heat is concentrated at the strain gauge location, preventing the heat from spreading to other areas of the flexible wheel 1, thereby achieving glass micro-melting sintering while keeping the temperature rise of the rest of the flexible wheel 1 within the allowable range.

[0048] Furthermore, multiple sets of positive V-shaped silicon strain gauges are arranged at equal angular intervals along the circumference of the flexible wheel 1; Multiple sets of positive V-type silicon strain gauges are connected to form a Wheatstone bridge, with at least two sets.

[0049] Furthermore, two positive V-shaped silicon strain gauges are symmetrically arranged 180° apart along the circumference of the flexible wheel 1. The two resistance bars of each positive V-shaped silicon strain gauge are respectively connected to the adjacent arms of the Wheatstone bridge, and the four resistance bars form a full bridge.

[0050] Multiple sets of positive V-shaped silicon strain gauges are arranged in 2, 8, or 24 groups at equal angular intervals along the circumference of the flexible wheel.

[0051] Specifically, such as Figure 4 and Figure 5As shown, the semiconductor silicon strain gauges 3 can be connected in a bridge as follows: A pair of semiconductor silicon strain gauges 3 are positioned at 45° and 135° to the axis of the flexible wheel 1, respectively, to measure the tensile and compressive stresses of the flexible wheel 1. Multiple sets of semiconductor silicon strain gauges 3 are arranged at equal angular intervals along the circumference of the flexible wheel 1, with a minimum of 2 sets, forming a Wheatstone bridge. In multi-set applications, such as 8 or 24 sets, the typical way to form the bridge is as follows: adjacent or opposing strain gauges sense the tensile and compressive strains respectively, and are connected according to the adjacent arms of the Wheatstone bridge, so that the strain signals caused by the torque are superimposed and the interference signals are canceled.

[0052] As a preferred full-bridge topology, two positive V-shaped silicon strain gauges are symmetrically arranged 180° apart along the circumference of the flexure 1. The two resistors in each positive V-shaped chip are connected to adjacent arms of a Wheatstone bridge, forming a full bridge with the four resistors. Because the two chips are distributed opposite each other on the circumference, when the flexure 1 is subjected to torque, the tensile stress at one chip corresponds to the compressive stress at the other, doubling the bridge output. Simultaneously, when the flexure 1 is subjected to radial or axial disturbance forces, the two chips produce strain changes in the same direction, canceling each other out in the bridge. This "symmetrical double positive V-shaped full-bridge" structure has better common-mode rejection capability than the traditional four independent single-resistor full-bridge, and by utilizing the high temperature uniformity of the two resistors within the positive V-shaped chip, the temperature drift coefficient can be below 5ppm / ℃.

[0053] As an alternative half-bridge topology, a single positive V-shaped silicon strain gauge can also be used to form a half-bridge. It has a simple structure, low temperature drift, and is suitable for applications with high cost or space requirements.

[0054] like Figures 6 to 8 As shown, the semiconductor silicon strain gauge 3 also includes a half-bridge silicon strain gauge and a single-resistance silicon strain gauge.

[0055] like Figure 9 As shown, eight sets of silicon strain gauges can be arranged at equal angles around the flexure, or 24 sets or other numbers of sets can be arranged. Each set of strain gauges is connected to form a Wheatstone bridge to improve the redundancy and accuracy of the measurement.

[0056] Specifically, when using 8 sets of semiconductor silicon strain gauges 3, each pair of semiconductor silicon strain gauges 3 arranged opposite each other (180° apart) forms a full bridge, and the 8 sets form a total of 4 independent full bridges; similarly, when using 24 sets, 12 independent full bridges can be formed. The output signals of multiple full bridges can be connected in parallel, or they can be averaged and then connected to the signal processing circuit board assembly 4 to improve the redundancy and accuracy of the measurement.

[0057] Furthermore, the signal processing circuit board assembly 4 is an epoxy resin printed circuit board, a flexible circuit board, or a rigid-flex board, and the surface pads of the signal processing circuit board assembly 4 are gold-plated. The oil-resistant adhesive is a polyurethane adhesive, a fluorosilicone adhesive, or an epoxy resin adhesive; The signal processing circuit board assembly 4 is electrically connected to the semiconductor silicon strain gauge 3 via bonding leads; The semiconductor silicon strain gauge 3, the signal processing circuit board assembly 4, and the bonding leads are covered and protected by oil-resistant soft protective adhesive.

[0058] Specifically, such as Figure 10 As shown, the signal processing circuit is integrated on a circuit board assembly. The signal processing circuit board assembly 4 is a common epoxy resin PCB, flexible circuit board (FPC), or rigid-flex PCB, and the surface pads are gold-plated, providing good bonding wire (aluminum wire or gold wire) performance. Oil-resistant adhesive is used for bonding the circuit board. This adhesive has low hardness, ensuring that stress and strain are not transferred to the circuit board through the adhesive under the deformation conditions of the flexible wheel 1. It also ensures that the circuit board bonding can operate in a lubricating oil environment and maintain the bonding position and strength. Examples of suitable adhesives include polyurethane adhesives, fluorosilicone adhesives, or epoxy resin adhesives. Furthermore, the adhesive is required to have low hardness and low modulus. The circuit board and silicon strain gauge are protected with an oil-resistant soft protective adhesive. This oil-resistant soft protective adhesive has good coating properties, ensuring that the circuit board, silicon strain gauge, and bonding wires are all protected by the oil-resistant protective adhesive.

[0059] As a specific implementation method, the Shore hardness of the oil-resistant adhesive is A20 to A50, and the elastic modulus is 2 to 10 MPa. Preferably, the Shore hardness is not greater than A40 and the elastic modulus is not greater than 8 MPa, so that under the condition of deformation of the flexible wheel 1, stress and strain will not be transmitted to the signal processing circuit board assembly 4 through the oil-resistant adhesive.

[0060] Example 2

[0061] Based on Example 1, this embodiment provides a method for manufacturing a glass micro-fused torque sensor integrated with a positive V-shaped silicon strain gauge flexure wheel 1, including roughening the sensor surface of the flexure wheel 1; forming a glass body on the flexure wheel 1; placing a semiconductor silicon strain gauge 3 on the glass body and performing local heating sintering to fuse the semiconductor silicon strain gauge 3 and the glass body into one piece; applying an oil-resistant adhesive to bond the signal processing circuit board assembly 4 to the flexure wheel 1; performing wire bonding to electrically connect the signal processing circuit board assembly 4 and the semiconductor silicon strain gauge 3; and applying an oil-resistant soft protective adhesive.

[0062] The specific steps are as follows: S1. Roughen the sensor surface of the flexible wheel 1 by means of precision sandblasting, laser texturing or chemical etching; S2. Print, dispensing or spraying glass glue on the flexible wheel 1 that has completed S1, and then sinter to remove organic matter to form a glass body; S3. The positive V-shaped silicon strain gauge is bonded to the glass body and sintered by local laser heating or aerogel insulation heating in conjunction with a negative pressure system. The peak temperature is controlled within 380℃ and the heating duration does not exceed 5 seconds, so that the semiconductor silicon strain gauge 3 and the glass are sintered into one piece. S4. Apply oil-resistant adhesive and bond the circuit board assembly, perform lead bonding, and then apply oil-resistant soft protective adhesive. S5. Install the packaged flexible wheel 1 sensor module on a standard torque table to calibrate the torque and obtain a standard electrical signal for torque conversion.

[0063] Example 3

[0064] Based on Example 1, this embodiment provides a method for manufacturing a positive V-type silicon strain gauge, such as... Figure 11 As shown, it includes the following materials: 1. Select a high-resistivity N-type silicon wafer; 2. Epitaxially grow a P-type epitaxial layer with a specific doping concentration on the silicon wafer, with a thickness of 2μm; 3. Photolithographically etch the boron-rich region and perform high-doped boron implantation to form the P+ region; 4. Photolithographically etch the resistor strips and use DRIE to etch the resistor strips to a depth of 2μm; 5. Deposit silicon oxynitride; 6. Photolithographically etch the lead holes to expose them; 7. Deposit a metal layer, including an adhesion layer, an isolation layer, and aluminum metal, and perform pattern etching; 8. Perform high-temperature metallization to form ohmic connections; 9. Photolithographically etch the deep region to form the depth direction and shape of the figure-eight strain gauge; 10. Protect the entire surface by thinning and etching the wafer; 11. Release to form a single positive V-type strain gauge.

[0065] The positive V-type silicon strain gauge is fabricated through the following steps: A P-type epitaxial layer is formed on a silicon wafer; a boron-rich region is photolithographically etched on the P-type epitaxial layer, and boron implantation is performed to form a P+ region; a resistance strip pattern is photolithographically etched on the P-type epitaxial layer containing the P+ region, and deep reactive ion etching (DRIE) is used to etch the P-type epitaxial layer to a predetermined depth to form two mutually perpendicular resistance strips; silicon oxynitride is deposited on the etched resistance strip structure, and lead holes are formed by photolithography and etching; a metal layer is deposited at the lead holes, and ohmic connections are formed by high-temperature metallization; a deep region is photolithographically etched on the metallized structure to form the outline of a positive V-type strain gauge; the wafer is thinned and etched on the back side to release and form a single positive V-type silicon strain gauge.

[0066] Example 4

[0067] This embodiment provides an implementation method for low-temperature glass micro-melting sintering.

[0068] Low-temperature silicone sealant is applied to the surface of the flexible wheel sensor via screen printing or stencil printing. First, pre-sintering at below 400°C removes organic matter, forming a glass body. Then, a positive V-shaped silicon strain gauge is placed on the glass body, and a laser is used to rapidly scan and heat it along the periphery of the strain gauge. The diameter of the laser-heated area is only 2-3 mm larger than the strain gauge size, and the heating duration does not exceed 5 seconds, with the peak temperature controlled below 380°C. Simultaneously, a negative pressure system (e.g., -0.08 MPa) is activated to help expel air bubbles between the molten glass and the metal surface, ensuring a strong micro-fusion bond between the glass body, the flexible wheel's metal surface, and the silicon strain gauge. Because heating is limited to the strain gauge area, the temperature rise of the rest of the flexible wheel is minimal, preventing damage to the hardness and fatigue properties obtained through precision heat treatment.

[0069] To illustrate, as a comparison, the flexible wheels of the same batch were heated to 400°C and held at that temperature for 10 minutes. Testing showed that their surface hardness decreased by approximately 15%, and their fatigue life (10... 7 The temperature drops by about 20% per cycle. However, with the local heating method in this embodiment, the peak temperature is controlled below 380°C and the heating duration does not exceed 5 seconds. After sintering, the change in hardness and fatigue life of the flexible wheel matrix is ​​less than 3%.

[0070] It is understandable that the lower the sintering temperature and the shorter the heating duration, the smaller the impact on the material properties of the flexible wheel 1; the sintering temperature can be, for example, 350℃~400℃, and the specific parameters can be adjusted according to the heat treatment characteristics of the flexible wheel 1 material.

[0071] Example 5

[0072] This embodiment provides an oil-resistant encapsulation and signal processing implementation method.

[0073] The circuit board assembly uses a rigid-flex PCB with gold-plated pads. The leads of the silicon strain gauge are bonded to the circuit board pads via gold or aluminum wire bonding. The circuit board is bonded to the flexible wheel using a low-hardness, low-modulus polyurethane adhesive, preventing stress and strain generated by the deformation of the flexible wheel from being transmitted to the circuit board. Subsequently, an oil-resistant soft protective adhesive is applied to the surfaces of the circuit board, silicon strain gauge, and bonding leads. This oil-resistant soft protective adhesive has good coating properties and can operate for a long time in the environment of the gearbox lubricating oil, ensuring the reliability of the electrical connection and positional stability. After packaging, the flexible wheel sensor module is mounted on a standard torque stage for multi-point calibration to establish the correspondence between torque and bridge output voltage, obtaining a standard electrical signal for torque conversion.

[0074] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0075] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0076] In the embodiments disclosed in this application, it should be understood that the disclosed devices / terminal equipment and methods can be implemented in other ways. For example, the device / terminal equipment embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling or direct coupling or communication connection may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0077] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

Claims

1. A positive V-shaped silicon strain gauge flexible wheel integrated with a glass micro-fusion torque sensor, characterized in that, include: Flexible wheel; the flexible wheel is equipped with a sensing component; The sensing component includes a glass layer and a semiconductor silicon strain gauge; The glass layer is fused to the metal surface of the flexible wheel, and the semiconductor silicon strain gauge is embedded in the glass layer; A signal processing circuit board assembly; the signal processing circuit board assembly is bonded to the flexible wheel by an oil-resistant adhesive and is electrically connected to the semiconductor silicon strain gauge.

2. The positive V-shaped silicon strain gauge flexible wheel integrated glass micro-fusion torque sensor according to claim 1, characterized in that, The semiconductor silicon strain gauge includes a positive V-type silicon strain gauge; The flexible wheel includes a diaphragm, and the center of the semiconductor silicon strain gauge is offset from the median diameter circle of the diaphragm in the radial direction by at least 0.5 mm; The positive V-shaped silicon strain gauge integrates two mutually perpendicular resistance bars on the same chip using MEMS technology. The angular error between the two resistor bars is within ±0.1°; The symmetry line of the positive V-shaped silicon strain gauge is set along the radial direction of the flexible wheel, so that the two resistance bars are respectively aligned with the principal stress directions of 45° and 135° on the diaphragm surface; The semiconductor silicon strain gauge also includes a half-bridge silicon strain gauge and a single-resistance silicon strain gauge.

3. The positive V-shaped silicon strain gauge flexible wheel integrated glass micro-fusion torque sensor according to claim 1, characterized in that, The glass layer is formed by local heating and sintering of glass adhesive at a temperature below 400°C. The local heating is either laser local heating or aerogel insulation local heating, combined with a negative pressure system; The peak temperature of the local heating area is controlled below 380℃, and the heating duration does not exceed 5 seconds.

4. The positive V-shaped silicon strain gauge flexible wheel integrated glass micro-fusion torque sensor according to claim 1, characterized in that, Multiple sets of positive V-type silicon strain gauges are arranged at equal angular intervals along the circumference of the flexible wheel; The multiple sets of positive V-shaped silicon strain gauges are connected to form a Wheatstone bridge, and there are at least two sets.

5. The positive V-shaped silicon strain gauge flexible wheel integrated glass micro-fusion torque sensor according to claim 4, characterized in that, Two positive V-shaped silicon strain gauges are symmetrically arranged 180° apart along the circumference of the flexible wheel. The two resistance bars of each positive V-shaped silicon strain gauge are respectively connected to the adjacent bridge arm of the Wheatstone bridge, and the four resistance bars form a full bridge.

6. The V-shaped silicon strain gauge flexible wheel integrated glass micro-fusion torque sensor according to claim 1, characterized in that, The signal processing circuit board assembly is an epoxy resin printed circuit board, a flexible circuit board, or a rigid-flex board, and the surface pads of the signal processing circuit board assembly are gold-plated. The oil-resistant adhesive is a polyurethane adhesive, a fluorosilicone adhesive, or an epoxy resin adhesive. The signal processing circuit board assembly is electrically connected to the semiconductor silicon strain gauge via bonding leads; The semiconductor silicon strain gauge, signal processing circuit board assembly, and bonding wires are covered and protected by an oil-resistant soft protective adhesive.

7. The V-shaped silicon strain gauge flexible wheel integrated glass micro-fusion torque sensor according to claim 3, characterized in that, The glass adhesive is formed on a flexible roller by screen printing, stencil printing, trajectory dispensing or spraying, and sintered at a temperature below 400°C.

8. The V-shaped silicon strain gauge flexible wheel integrated glass micro-fusion torque sensor according to claim 4, characterized in that, The multiple sets of positive V-shaped silicon strain gauges are arranged in 2, 8, or 24 sets at equal angular intervals along the circumference of the flexible wheel.

9. A method for manufacturing a glass micro-fusing torque sensor integrated with a flexural wheel of a positive V-type silicon strain gauge as described in claim 1, characterized in that, include: The sensor surface of the flexible wheel is roughened. A glassy body is formed on the flexible wheel; The semiconductor silicon strain gauge is placed on the glass body and subjected to local heating and sintering to fuse the semiconductor silicon strain gauge and the glass body into one piece. Apply oil-resistant adhesive and bond the signal processing circuit board assembly to the flexible wheel; Wire bonding is performed to electrically connect the signal processing circuit board assembly to the semiconductor silicon strain gauge; Apply an oil-resistant soft protective coating.

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