Torque sensor based on structural decoupling

Abstract

A torque sensor based on structural decoupling comprises a sensitive element body, the lower portion of the sensitive element body is connected with a test circuit board, and the test circuit board is installed in a lower cover plate; an upper cover plate covers the upper part of the sensitive element main body, and the upper cover plate is connected with the lower cover plate to package the sensitive element main body and the test circuit board; the middle part of the sensitive element main body comprises a splined hole, the periphery of the splined hole is provided with a positioning groove, the left and right sides of the splined hole are provided with support beams, and the upper and lower sides of the splined hole are provided with strain beams; according to the invention, the sensor can suppress the output change caused by the force or torque in the non-sensitive direction through a structural decoupling mode, so that only the torque in the specified direction is measured; the structure and the circuit are simple, the driving mode is easy to realize and adjust, the technology is simple, the structure is stable, processing is easy, and the method can be widely applied to various torque measurement scenes.

Description

Technical Field

[0001] The present invention belongs to the technical field of torque sensors, and in particular relates to a torque sensor based on structural decoupling. Background Art

[0002] Torque sensors are an indispensable component of torque testing and are primarily used to measure various torques, rotational speeds, and mechanical power. In recent years, research has been conducted both domestically and internationally on passive and wireless sensor measurement, dynamic torque testing, sensor dynamic characteristics, and novel torque measurement methods. Surface acoustic wave (SAW), magnetoelastic, angular, and strain-sensing torque sensors have been developed based on various measurement principles. While a growing number of new torque sensors are emerging, and their performance is gradually improving, many challenging challenges remain in their practical applications. These include difficulties in completing dynamic torque tests, inability to adapt to harsh environments, susceptibility to interference from temperature, electromagnetic interference, ambient light, and dust, poor temperature stability, and measurement accuracy that has yet to meet practical application requirements.

[0003] Among the currently available literature, there are few studies on torque sensors that can only measure torque in a specified direction and are insensitive to force and torque changes in other directions. The patent application entitled "A Torque Measurement Method Based on the Hall Effect" (publication number CN 117647345B) can enrich the current torque measurement work and needs, but does not provide a specific torque sensor design solution; the patent application entitled "Torque Measurement Device and Torque Control Method" (publication number CN117928796A) introduces a measuring device that can achieve remote measurement and control of the spindle torque of the device under test, but the device uses a hydraulic system and it is difficult to achieve high measurement accuracy; the patent application entitled "A Static Torque Measuring Instrument" (publication number CN 220912516U) introduces a measuring instrument that can clamp and fix output shafts of different shapes and specifications to measure static torque, but does not involve technology for measuring torque only in a specified direction.

[0004] In summary, the existing torque sensors have low accuracy, complex structure and processing, and cannot meet the various torque measurement requirements of today. Summary of the Invention

[0005] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a torque sensor based on structural decoupling. Through structural decoupling, the sensor can suppress the output changes caused by force or torque in non-sensitive directions, so that only the torque in the specified direction is measured; the structure and circuit are simple, the driving method is easy to implement and adjust, and it has the advantages of simple process, stable structure and easy processing, and can be widely used in various torque measurement scenarios.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A torque sensor based on structural decoupling includes a sensitive element body 4, the lower part of which is connected to a test circuit board 9, which is installed in a lower cover plate 10; an upper cover plate 1 is provided on the upper part of the sensitive element body 4, and the upper cover plate 1 is connected to the lower cover plate 10 to encapsulate the sensitive element body 4 and the test circuit board 9.

[0008] The middle part of the sensor body 4 includes a spline hole 5 for applying force or torque. The outer periphery of the spline hole 5 is provided with a positioning groove 6 for positioning the upper cover plate 1. The left and right sides of the spline hole 5 are provided with support beams 7 for improving the rigidity of the sensor body 4. The upper and lower sides of the spline hole 5 are provided with strain beams 8 for transmitting the strain caused by the force or torque applied to the sensor body 4.

[0009] A connecting plate 3 is installed in each of the four grooves of the sensitive element body 4. A detection unit is attached to the top of each connecting plate 3. The four detection units are the first detection unit 2-1, the second detection unit 2-2, the third detection unit 2-3, and the fourth detection unit 2-4.

[0010] The test circuit board 9 is powered by an external power supply through an interface, and drives the first detection unit 2-1, the second detection unit 2-2, the third detection unit 2-3, and the fourth detection unit 2-4 through the connection board 3 and detects changes therein.

[0011] The testing circuit board 9 is provided with an interface, and the interface is placed on the hollow portion of the sensitive element body 4; the circuit components are installed below the testing circuit board 9.

[0012] The first detection unit 2-1, the second detection unit 2-2, the third detection unit 2-3, and the fourth detection unit 2-4 are driven by electrostatics.

[0013] The first detection unit 2-1, the second detection unit 2-2, the third detection unit 2-3, and the fourth detection unit 2-4 collect the changes in the values ​​to be detected through the test circuit board 9 and the connecting board 3, and calculate the detection values ​​of the first detection unit 2-1, the second detection unit 2-2, the third detection unit 2-3, and the fourth detection unit 2-4 through numerical difference to obtain the sensitivity of the sensor in measuring the torque in the specified direction.

[0014] The outer diameter of the upper cover 1 is equal to the outer diameter of the lower cover 10 ; the outer diameter of the sensitive element body 4 is equal to the diameter of the test circuit board 9 ; the outer diameter of the sensitive element body 4 is smaller than the inner diameter of the lower cover 10 .

[0015] The diameter of the middle through hole on the upper cover plate 1 is larger than the diameter of the middle hole on the sensitive element body 4 ; the diameter of the middle hole of the test circuit board 9 is larger than the diameter of the middle circular boss of the lower cover plate 10 .

[0016] The upper cover plate 1 , the sensor body 4 and the test circuit board 9 are connected to the lower cover plate 10 by screws.

[0017] The diameters of the upper cover plate 1 and the lower cover plate 10 are set to 140-142 mm, the thickness of the upper cover plate 1 is set to 17-18 mm, and the thickness of the lower cover plate 10 is set to 28-28.5 mm; the thickness of the sensitive element body 4 is set to 9-10 mm, and the diameter is set to 98-102 mm.

[0018] Compared with the prior art, the present invention has the following beneficial effects: since the present invention adopts four detection units, it has the advantage of high measurement accuracy; since the present invention adopts structural decoupling, it only measures the torque in a specific direction and avoids crosstalk between torque and force in other directions, so it has the advantage of high torque measurement accuracy; since the structure and circuit adopted by the present invention are simple and the driving method is easy to implement and adjust, it has the advantages of simple process, stable structure and easy processing, and can be widely used in various torque measurement scenarios.

[0019] In the present invention, four detection units are selected, and the torque can be conveniently transmitted to the detection unit through the strain beam, causing the detection value to change, achieving the correspondence between the torque and the detection value changes, and reducing parasitic vibration, which is beneficial to improving the performance of the sensor.

[0020] The dimensions of the upper cover plate and the lower cover plate of the present invention determine the overall size, rigidity and strength of the torque sensor, and ensure that the sensitive element body and the circuit board can be packaged.

[0021] The thickness and size of the strain beam and the support beam of the main body of the sensitive element of the present invention affect the range and sensitivity of the sensor in measuring torque, and the thickness and diameter of the main body of the sensitive element determine the strength and rigidity of the sensor.

[0022] The detection units of the present invention affect the accuracy and range of torque measurement by the sensor; the spatial distribution of the four detection units determines that when the sensor is subjected to a force on an axis perpendicular to the plane of the sensitive element body, a differential method can be used to improve the sensitivity of the sensor.

[0023] The middle part of the main body of the sensitive element of the present invention adopts a spline hole structure, which can be easily inserted into the spline shaft and exert torque on the shaft to achieve torque measurement.

[0024] Comprehensive analysis shows that the present invention provides a torque sensor based on structural decoupling. The invention has a simple structure and circuit, and the driving method is easy to implement and adjust. It has the advantages of simple process, stable structure and easy processing. It can measure the torque in a specified direction and suppress the influence of forces and torques in other directions. It can be widely used in various torque measurement scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of an embodiment of the present invention.

[0026] Figure 2 Schematic diagram of the torque applied on the axis (Z axis) perpendicular to the main body of the sensitive element according to an embodiment of the present invention.

[0027] Figure 3 A tuning fork is selected as the detection unit in the embodiment of the present invention. A schematic diagram of the stress distribution and displacement change of the sensing element body when subjected to a torque of 20 N·m along an axis perpendicular to the sensing element body (Z axis) in a simulation is shown.

[0028] Figure 4 In the embodiment of the present invention, tuning forks are selected as detection units. In the experiment, when a torque is applied on an axis perpendicular to the main body of the sensitive element (Z axis), the resonant frequency of the four tuning forks changes with the torque.

[0029] Figure 5 In the embodiment of the present invention, a tuning fork is selected as the detection unit. In the experiment, when subjected to torque on the axis perpendicular to the sensitive element body (Z axis) and on the X axis and Y axis perpendicular to the Z axis, the sensor uses structural decoupling, that is, the resonant frequency changes of the four tuning forks are calculated by differential calculation to obtain the sensor torque sensitivity curve.

[0030] Figure 6 In the embodiment of the present invention, a tuning fork is selected as the detection unit. In the experiment, when subjected to forces on the axis perpendicular to the main body of the sensitive element (Z axis) and on the X and Y axes perpendicular to the Z axis, the sensor uses structural decoupling, that is, the resonant frequency changes of the four tuning forks are calculated by differential calculation to obtain the sensor force sensitivity curve.

[0031] In the figure: 1 is the upper cover, 2-1 is the first detection unit, 2-2 is the second detection unit, 2-3 is the third detection unit, 2-4 is the fourth detection unit, 3 is the connecting plate, 4 is the sensitive element body, 5 is the spline hole, 6 is the positioning groove, 7 is the support beam, 8 is the strain beam, 9 is the test circuit board, and 10 is the lower cover. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments and drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] Reference Figure 1 A torque sensor based on structural decoupling includes: an upper cover 1, a first detection unit 2-1, a second detection unit 2-2, a third detection unit 2-3, a fourth detection unit 2-4, a connecting plate 3, a sensitive element body 4, a spline hole 5, a positioning groove 6, a support beam 7, a strain beam 8, a test circuit board 9, and a lower cover 10; the lower part of the sensitive element body 4 is connected to the test circuit board 9, and the test circuit board 9 is installed in the lower cover 10; the middle part of the sensitive element body 4 includes a spline hole 5 for applying force or torque, and the outer periphery of the spline hole 5 is provided with a positioning groove 6 for positioning the upper cover 1, the left and right sides of the spline hole 5 are provided with support beams 7 for improving the rigidity of the sensitive element body 4, and the upper and lower sides of the spline hole 5 are provided with strain beams 8 for transmitting the strain caused by the force or torque applied to the sensitive element body 4; the upper part of the sensitive element body 4 is provided with an upper cover 1, and the key on the upper cover 1 cooperates with the positioning groove 6 on the sensitive element body 4, the upper cover 1 and the lower cover 10 are connected to encapsulate the sensitive element body 4 and the test circuit board 9.

[0034] A connecting plate 3 is installed in each of the four grooves of the sensitive element body 4, and a detection unit is attached to the upper part of each connecting plate 3. In this embodiment, there are four detection units, namely the first detection unit 2-1, the second detection unit 2-2, the third detection unit 2-3, and the fourth detection unit 2-4.

[0035] The outer diameter of the upper cover 1 is equal to the outer diameter of the lower cover 10 ; the outer diameter of the sensitive element body 4 is equal to the diameter of the test circuit board 9 ; the outer diameter of the sensitive element body 4 is smaller than the inner diameter of the lower cover 10 .

[0036] The test circuit board 9 is powered by an external power supply through an interface, and drives the first detection unit 2-1, the second detection unit 2-2, the third detection unit 2-3, and the fourth detection unit 2-4 through the connection board 3 and detects changes therein.

[0037] The diameter of the middle through hole on the upper cover plate 1 is larger than the diameter of the middle hole on the sensitive element body 4 ; the diameter of the middle hole of the test circuit board 9 is larger than the diameter of the middle circular boss of the lower cover plate 10 .

[0038] The testing circuit board 9 is provided with an interface, and the interface is placed on the hollow portion of the sensitive element body 4; the circuit components are installed under the testing circuit board 10.

[0039] The upper cover plate 1 , the sensor body 4 and the test circuit board 9 are connected to the lower cover plate 10 by screws.

[0040] The first detection unit 2-1, the second detection unit 2-2, the third detection unit 2-3, and the fourth detection unit 2-4 are driven by electrostatics.

[0041] The first detection unit 2-1, the second detection unit 2-2, the third detection unit 2-3, and the fourth detection unit 2-4 can collect the changes in the values ​​to be detected through the test circuit board 9 and the connecting board 3, and the detection values ​​of the first detection unit 2-1, the second detection unit 2-2, the third detection unit 2-3, and the fourth detection unit 2-4 can be calculated through numerical difference to obtain the sensitivity of the sensor in measuring the torque in the specified direction.

[0042] Reference Figure 2 , Figure 2 This is a schematic diagram of the torque model applied on the axis (Z axis) perpendicular to the main body of the sensitive element in the sensor calibration experiment of this embodiment. Figure 3 , Figure 3 The tuning fork is selected as the detection unit in this embodiment. The stress distribution and displacement change diagram of the sensitive element body when subjected to a torque of 20N*m on the axis perpendicular to the sensitive element body (Z axis) in the simulation. When the middle part of the sensitive element body is subjected to torque, the force will be transmitted to the tuning fork attached to the connecting plate through the support beam in the structure, causing the stress of the four tuning forks in the structure to change. Figure 4 , Figure 4 In this embodiment, tuning forks are selected as detection units. According to the sensor structural parameters in Table 1, the resonant frequency of the four tuning forks varies with torque when subjected to torque on an axis perpendicular to the main body of the sensitive element (Z axis) in the experiment. The test circuit board is connected to an external power supply interface, and the test circuit board can be connected to the electrodes on the tuning forks through a connecting board, thereby driving the tuning forks and detecting their resonant frequencies. It can be seen from the figure that the resonant frequencies of tuning forks 1 and 4 increase, while the resonant frequencies of tuning forks 2 and 3 decrease. Figure 5 , Figure 5A tuning fork is selected as the detection unit for this embodiment. In the experiment, when subjected to torque on the axis perpendicular to the main body of the sensitive element (Z axis) and on the X axis and Y axis perpendicular to the Z axis, the sensor decouples the structure, that is, the resonant frequency changes of the four tuning forks are calculated by differential calculation. The sensor torque sensitivity curve reflects the sensitivity that the present invention can achieve when measuring torque. The present invention is used to measure the torque on the axis perpendicular to the main body of the sensitive element (Z axis). The layout of the tuning fork structure can improve its sensitivity by differential calculation. When subjected to torque on the X axis and Y axis, the frequency change can be eliminated by structural decoupling, so that the torque sensor is only sensitive to the torque on the axis perpendicular to the main body of the sensitive element, that is, Δf = (Δf1-Δf2)-(Δf3-Δf4). The various index parameters of the sensor can be obtained. When measuring the torque on the Z axis, the sensitivity is 381Hz / N·m, when measuring the torque on the X axis, the sensitivity is 0.14Hz / N·m, and when measuring the torque on the Y axis, the sensitivity is 0.16Hz / N·m. Figure 6 , Figure 6 When a tuning fork is selected as the detection unit for this embodiment, when subjected to forces on the axis perpendicular to the sensitive element body (Z axis) and on the X and Y axes perpendicular to the Z axis in the experiment, the sensor achieves a force sensitivity curve of the sensor by differential calculation of the resonant frequency changes of the four tuning forks through structural decoupling.

[0043] Table 2 shows the frequency response of the sensor when a tuning fork is used as the detection unit in the experiment. When the tuning fork is applied to the force and torque on the X, Y, and Z axes, the Z axis is perpendicular to the plane of the sensitive element. By comparing the force and torque sensitivity of the sensor in various directions, it can be seen that the sensor can be used to measure torque in the Z axis direction.

[0044] Table 1 Sensor structural parameters

[0045]

[0046]

[0047] Table 2 Sensor frequency response when force and torque are applied

[0048] Mz Mx My Fz Fx Fy 381Hz / N*m 0.14Hz / N*m 0.16Hz / N*m 0.0054Hz / N 0.000062Hz / N 0.8Hz / N

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A torque sensor based on structural decoupling, comprising a sensitive element body (4), characterized in that: The lower part of the sensitive element body (4) is connected to a test circuit board (9), and the test circuit board (9) is installed in a lower cover plate (10); the upper part of the sensitive element body (4) is provided with an upper cover plate (1), and the upper cover plate (1) and the lower cover plate (10) are connected to encapsulate the sensitive element body (4) and the test circuit board (9).

2. The torque sensor according to claim 1, wherein: The middle portion of the sensor body (4) includes a spline hole (5) for applying force or torque, a positioning groove (6) for positioning the upper cover plate (1) is formed on the periphery of the spline hole (5), support beams (7) for improving the rigidity of the sensor body (4) are provided on the left and right sides of the spline hole (5), and strain beams (8) for transmitting strain caused by the force or torque applied to the sensor body (4) are provided on the upper and lower sides of the spline hole (5).

3. The torque sensor according to claim 1, wherein: A connecting plate (3) is respectively installed in the four grooves of the sensitive element body (4), and a detection unit is attached to the upper part of each connecting plate (3). The four detection units are a first detection unit (2-1), a second detection unit (2-2), a third detection unit (2-3), and a fourth detection unit (2-4).

4. The torque sensor according to claim 3, wherein: The test circuit board (9) is powered by an external power supply through an interface, and drives the first detection unit (2-1), the second detection unit (2-2), the third detection unit (2-3), and the fourth detection unit (2-4) through the connection board (3) and detects changes therein.

5. The torque sensor according to claim 3, wherein: An interface is provided on the test circuit board (9), and the interface is placed on a hollow portion of the sensitive element body (4); circuit components are installed below the test circuit board (9).

6. The torque sensor according to claim 3, characterized in that: The first detection unit (2-1), the second detection unit (2-2), the third detection unit (2-3), and the fourth detection unit (2-4) are driven by electrostatics.

7. The torque sensor according to claim 3, characterized in that: The first detection unit (2-1), the second detection unit (2-2), the third detection unit (2-3), and the fourth detection unit (2-4) collect the variation of the value to be detected through the test circuit board (9) and the connection board (3), and calculate the detection values ​​of the first detection unit (2-1), the second detection unit (2-2), the third detection unit (2-3), and the fourth detection unit (2-4) through numerical difference to obtain the sensitivity of the sensor in measuring the torque in the specified direction.

8. The torque sensor according to claim 1, wherein: The outer diameter of the upper cover plate (1) is equal to the outer diameter of the lower cover plate (10); the outer diameter of the sensitive element body (4) is equal to the diameter of the test circuit board (9); and the outer diameter of the sensitive element body (4) is smaller than the inner diameter of the lower cover plate (10).

9. The torque sensor according to claim 1, wherein: The diameter of the middle through hole on the upper cover plate (1) is larger than the diameter of the middle hole on the sensitive element body (4); the diameter of the middle hole on the test circuit board (9) is larger than the diameter of the middle circular boss on the lower cover plate (10).

10. The torque sensor according to claim 1, wherein: The diameters of the upper cover plate (1) and the lower cover plate (10) are set to 140-142 mm, the thickness of the upper cover plate (1) is set to 17-18 mm, and the thickness of the lower cover plate (10) is set to 28-28.5 mm; the thickness of the sensitive element body (4) is set to 9-10 mm, and the diameter is set to 98-102 mm.

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