Torque measuring device based on magnetic field sensing and measuring method thereof

Abstract

The invention provides a torque measuring device based on magnetic field sensing and a measuring method thereof. The torque measuring device based on magnetic field sensing comprises a measured shaft, a first signal gear, a second signal gear, a first torque sensor, a second torque sensor, a phase difference measuring module and an output module. A preset length interval is reserved between the first signal gear and the second signal gear; the first torque sensor is used for detecting and generating a first path of signal; the second torque sensor detects and generates a second path of signal; the phase difference measurement module is electrically connected with the first torque sensor and the second torque sensor. And the output module is electrically connected with the phase difference measurement module. Signals are generated through the first signal gear and the second signal gear by using different torque sensors, and torque measurement and calculation are performed, so that the technical problem that a torque measurement device in a complex detection environment is lacked in the prior art is solved.

Description

Technical field:

[0001] The present invention relates to the technical field of torque measurement, and in particular to a torque measurement device based on magnetic field sensing and a measurement method thereof. Background technology:

[0002] Torque is one of the most important technical parameters of rotating machinery and equipment. The actual measurement and monitoring of torque is an important means to achieve mechanical equipment status monitoring and intelligent control. The detection of torque can evaluate the performance of the entire mechanical transmission system, including the power output, energy consumption, service life, safety and stability of the system.

[0003] Torque measurement research has always been concerned by the field of metrology and testing at home and abroad. At present, the more mature shaft torque measurement methods mainly include strain type, magnetoelasticity and angle type. As the most basic and classic existence in the field of torque measurement, strain type torque sensors are mostly contact sensors, which will introduce additional mechanical interference and friction to a large extent, reduce the reliability of measurement and the accuracy of data, and also bring many inconveniences to installation. In recent years, strain type non-contact torque sensors with wireless power supply have been introduced, which facilitates the installation and use of sensors, but their data transmission and anti-interference problems still need to be improved. The structure of magnetoelastic sensors is relatively complex, and the field working conditions and environmental factors have a great influence on the performance of magnetic materials, which directly affects the accuracy of measurement, so they are rarely used on site. The angle measurement method has obvious advantages in shaft torque measurement because it is easy to achieve non-contact measurement. Common angle torque sensors include photoelectric, magnetoelectric and magnetic field sensing. Photoelectric torque sensors are more sensitive to on-site light pollution and have more stringent requirements for the detection environment, while magnetoelectric torque sensors have weak output signals at low and medium speeds and often require the addition of auxiliary motors, which increases the complexity and cost of the sensor. Magnetic field sensing torque sensors use magnetic sensing technology to sense the rotation of gears to obtain the torsion angle of the shaft, but the installation distance from the gears often causes changes in the signal amplitude, affecting the accuracy of torque measurement. These defects directly limit the practical engineering application of these measurement methods in harsh environments.

[0004] There is an urgent need for a torque measurement device based on magnetic field sensing and a measurement method thereof, which can help solve the technical problem of the lack of a torque measurement device in a complex detection environment in the prior art. Summary of the invention:

[0005] In one embodiment, the present invention provides a torque measurement device based on magnetic field sensing, which generates signals using different torque sensors through a first signal gear and a second signal gear, and performs torque measurement calculations, which helps to solve the technical problem in the prior art of lacking a torque measurement device in a complex detection environment.

[0006] The torque measuring device based on magnetic field sensing includes a measured shaft and a first signal gear, a second signal gear, a first torque sensor and a second torque sensor, a phase difference measuring module, and an output module;

[0007] The first signal gear is sleeved on one end of the measured shaft;

[0008] The second signal gear is sleeved on the other end of the measured shaft, and a predetermined length interval is left between the first signal gear and the second signal gear;

[0009] The first torque sensor is used to detect that the first signal gear generates a first signal;

[0010] The second torque sensor is used to detect that the second signal gear generates a second signal;

[0011] The phase difference measurement module is electrically connected to the first torque sensor and the second torque sensor respectively;

[0012] The output module is electrically connected to the phase difference measurement module.

[0013] In one embodiment, the first signal gear is made of ferromagnetic material, and the tooth shape is rectangular, involute, or polygonal.

[0014] In one embodiment, the first torque sensor includes a sensor housing, a magnetic sensor, a permanent magnet, and a signal conditioning circuit;

[0015] The sensor housing has an internal cavity;

[0016] The magnetic sensor is disposed in the internal cavity;

[0017] The permanent magnet is disposed in the internal cavity;

[0018] The signal conditioning circuit is also disposed within the internal cavity.

[0019] In one embodiment, the magnetic sensor is an integrated magnetic field sensor, and the magnetic sensor is a Hall sensor, or a magnetoresistive sensor, or a tunnel magnetoresistive sensor.

[0020] In one embodiment, the first torque sensor and the second torque sensor are on the same straight line.

[0021] In one embodiment, a distance between the first torque sensor and the first signal gear is smaller than a distance between the second torque sensor and the second signal gear.

[0022] In one embodiment, the first torque sensor and the second torque sensor have the same magnetic field sensitive direction.

[0023] In one embodiment, the magnetic pole of the permanent magnet points to the first signal gear, and the magnetic pole includes an N pole or an S pole; and the shape of the permanent magnet is a cylinder.

[0024] In one embodiment, the signal conditioning circuit includes an isolation protection module, a voltage control amplification module, a secondary amplification module, an amplitude detection module, and an amplitude adaptive shaping module.

[0025] In one embodiment, the present invention further provides a torque measurement method based on magnetic field sensing. Based on the torque measurement device based on magnetic field sensing, the measurement method includes:

[0026] Obtaining a zero-point phase difference when not loaded, wherein the measured shaft rotates when not loaded, and the first signal and the second signal output by the first torque sensor and the second torque sensor pass through the phase difference measurement module, and the phase difference between the two signals is Δφ0;

[0027] Obtaining a working phase difference during loading, wherein the measured shaft rotates under loading, and the first signal and the second signal output by the first torque sensor and the second torque sensor pass through a phase difference measurement module, and the phase difference between the two signals is Δφ1;

[0028] The output phase difference is calculated based on the phase differences Δφ0 and Δφ1. Description of the drawings:

[0029] Figure 1 A structural principle diagram of a torque measurement device based on magnetic field sensing provided in one embodiment of the present invention;

[0030] Figure 2 A simplified side view of the structure of a torque measuring device based on magnetic field sensing provided in another embodiment of the present invention;

[0031] Figure 3 A schematic diagram of the spatial positions of two magnetic field sensors in another embodiment of the present invention;

[0032] Figure 4 A schematic diagram of a signal conditioning circuit of a torque sensor in another embodiment of the present invention;

[0033] Figure 5 FIG. 4 is a schematic diagram of a signal waveform of a torque sensor in another embodiment of the present invention.

[0034] Reference numerals:

[0035] Measured axis 1

[0036] First signal gear 2A

[0037] Second signal gear 2B

[0038] First torque sensor 3A

[0039] Magnetic sensor 31

[0040] Permanent magnet 32

[0041] Signal conditioning circuit 33

[0042] Sensor housing 34

[0043] Second torque sensor 3B

[0044] Phase difference measurement module 4

[0045] Output module 5

[0046] Predetermined length interval L Specific embodiment:

[0047] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0048] Various aspects and features of the present application are described herein with reference to the accompanying drawings.

[0049] These and other characteristics of the present application will become apparent from the following description of a preferred form of embodiment given as a non-limiting example with reference to the accompanying drawings.

[0050] It should also be understood that, although the present application has been described with reference to some specific examples, those skilled in the art will be able to realize many other equivalent forms of the present application that have the features described in the claims and are therefore within the scope of protection defined thereby.

[0051] The above and other aspects, features and advantages of the present application will become more apparent in view of the following detailed description when taken in conjunction with the accompanying drawings.

[0052] Specific embodiments of the present application are described hereinafter with reference to the accompanying drawings; however, it should be understood that the embodiments applied for are merely examples of the present application, which may be implemented in a variety of ways. Well-known and / or repeated functions and structures are not described in detail to determine the true intent based on the user's historical operations and to avoid unnecessary or redundant details that make the present application unclear. Therefore, the specific structural and functional details applied for herein are not intended to be limiting, but are merely used as the basis and representative basis for the claims to teach those skilled in the art to use the present application in a variety of ways with substantially any suitable detailed structure.

[0053] This specification may use the phrases "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," all of which may refer to one or more of the same or different embodiments according to the present application.

[0054] Figure 1 A structural principle diagram of a torque measurement device based on magnetic field sensing provided in one embodiment of the present invention; Figure 2 A simplified side view of the structure of a torque measuring device based on magnetic field sensing provided in another embodiment of the present invention; Figure 3 A schematic diagram of the spatial positions of two magnetic field sensors in another embodiment of the present invention; Figure 4 A schematic diagram of a signal conditioning circuit of a torque sensor in another embodiment of the present invention; Figure 5 FIG. 4 is a schematic diagram of a signal waveform of a torque sensor in another embodiment of the present invention.

[0055] like Figures 1 to 5 As shown, the present invention provides a torque measuring device based on magnetic field sensing, the torque measuring device based on magnetic field sensing includes a measured shaft 1, a first signal gear 2A, a second signal gear 2B, a first torque sensor 3A, a second torque sensor 3B, a phase difference measuring module 4, and an output module 5;

[0056] The first signal gear 2A is sleeved on one end of the measured shaft 1;

[0057] The second signal gear 2B is sleeved on the other end of the measured shaft 1. A predetermined length interval L is left between the first signal gear 2A and the second signal gear 2B. The first signal gear 2A and the second signal gear 2B are arranged opposite to each other along the axial direction of the measured shaft 1. The distance between the first signal gear 2A and the second signal gear 2B is L.

[0058] The first torque sensor 3A is used to detect the first signal gear 2A to generate a first signal;

[0059] The second torque sensor 3B is used to detect the second signal gear 2B to generate a second signal; the torque sensors correspond to the signal gears one by one, and a torque sensor is fixed opposite to each signal gear.

[0060] The phase difference measurement module 4 is electrically connected to the first torque sensor 3A and the second torque sensor 3B respectively;

[0061] The output module 5 is electrically connected to the phase difference measurement module 4 .

[0062] In one embodiment, the first signal gear 2A is made of ferromagnetic material, preferably 45# steel, and the tooth shape is rectangular, involute, or polygonal.

[0063] In one embodiment, the first torque sensor 3A includes a sensor housing 34, a magnetic sensor 31, a permanent magnet 32, and a signal conditioning circuit 33;

[0064] The sensor housing 34 has an internal cavity;

[0065] The magnetic sensor 31 is disposed in the inner cavity;

[0066] The permanent magnet 32 ​​is placed in the internal cavity. The permanent magnet 32 ​​is a neodymium iron boron permanent magnet, and its shape is a cylinder with a diameter of 12 mm and a height of 5 mm.

[0067] Signal conditioning circuitry 33 is also disposed within the interior cavity.

[0068] In one embodiment, the magnetic sensor 31 is an integrated magnetic field sensor, and the magnetic sensor 31 is a Hall sensor, or a magnetoresistive sensor, or a tunnel magnetoresistive sensor.

[0069] In one embodiment, the first torque sensor 3A and the second torque sensor 3B are on the same straight line.

[0070] In one embodiment, the distance between the first torque sensor 3A and the first signal gear 2A is smaller than the distance between the second torque sensor 3B and the second signal gear 2B.

[0071] In one embodiment, the first torque sensor 3A and the second torque sensor 3B have the same magnetic field sensitive direction, the first signal gear 2A and the second signal gear 2B are radial (y direction) or circumferential (x direction).

[0072] In one embodiment, the magnetic pole of the permanent magnet 32 ​​points to the first signal gear 2A, and the magnetic pole includes an N pole or an S pole; the permanent magnet 32 ​​is in the shape of a cylinder.

[0073] In one embodiment, the signal conditioning circuit 33 includes an isolation protection module, a voltage control amplification module, a secondary amplification module, an amplitude detection module, and an amplitude adaptive shaping module.

[0074] The signal conditioning circuit 33 has an amplitude adaptive shaping function. The output signals of the two magnetic sensors 31 are subjected to overvoltage protection and impedance transformation by the isolation protection module, differentially amplified by the voltage control amplifier module and amplified by the secondary amplifier module, and then sent to the adaptive shaping module to shape the output square wave signal; the amplitude detection module performs amplitude detection on the output signal of the secondary amplifier module, and its output is used to control the automatic gain adjustment of the voltage control amplifier module, so that the voltage control amplifier module outputs a signal with stable amplitude; the output of the amplitude detection module is also used to control the threshold voltage of the amplitude adaptive shaping module, so that the comparison voltage of the amplitude adaptive shaping module can be automatically adjusted following the signal amplitude, and the output square wave signal will not change its phase information due to changes in the signal amplitude.

[0075] Isolation protection module, voltage control amplifier module, secondary amplifier module, amplitude detection module, amplitude adaptive shaping module. In one embodiment, the voltage control amplifier module adopts VCA810 voltage-controlled gain amplifier, whose voltage control gain ranges from -40 to 40 dB, and the comparison voltage U H and U L It can be automatically adjusted according to the signal amplitude. When the stable amplitude signal output by the secondary amplifier module is ±4V, U H and = 1.2V, U L =0.6V. In another embodiment, when the amplitude-stabilized signal output by the secondary amplification module is ±3.8V, U H and = 1.14V, U L =0.57V.

[0076] In one embodiment, the present invention further provides a torque measurement method based on magnetic field sensing. Based on the torque measurement device based on magnetic field sensing, the measurement method includes:

[0077] Obtaining a zero-point phase difference when not loaded, wherein the measured shaft (1) rotates when not loaded, and a first signal and a second signal output by the first torque sensor (3A) and the second torque sensor (3B) pass through the phase difference measurement module (4), and a phase difference between the two signals is Δφ0;

[0078] Obtaining a working phase difference when loaded, wherein the measured shaft (1) rotates when loaded, and a first signal and a second signal output by the first torque sensor (3A) and the second torque sensor (3B) pass through a phase difference measurement module (4), and a phase difference of Δφ1 is obtained between the two signals;

[0079] The output phase difference is calculated based on the phase differences Δφ0 and Δφ1.

[0080] The torque measurement method based on magnetic field sensing is to calculate the effective phase difference φ according to the formula φ=Δφ1-Δφ0; and calculate the torque M of the measured shaft 1 according to the following formula.

[0081]

[0082] Where M is the torque of the measured shaft, m is the number of teeth of the signal gear, L is the center distance between the two signal gears, r is the radius of the measured shaft, G is the shear elastic modulus of the measured shaft, and φ is the effective phase difference φ.

[0083] Specifically, the measuring device is installed by selecting two measuring points with a certain axial distance L on the measured shaft, installing and tightening the signal gear; fixing a torque sensor (3) at the middle of each signal gear, connecting the signals of the two torque sensors (3) to a phase difference measuring module (4), and connecting the phase difference measuring module (4) to a signal processing and output module (5).

[0084] 2) Obtaining the zero-point phase difference when not loaded: The measured shaft rotates without loading, and the first signal and the second signal output by the two torque sensors pass through the phase difference measurement module to obtain a phase difference of Δφ0 between the two signals.

[0085] 3) Obtaining the working phase difference during loading: The measured shaft rotates under loading, and the first signal and the second signal output by the two torque sensors pass through the phase difference measurement module to obtain a phase difference of Δφ1 between the two signals.

[0086] In one embodiment, the phase difference is measured by FPGA using a pulse counting method, such as Figure 5 , start counting at the rising edge of the first signal output by the torque sensor, stop counting at the next rising edge, and obtain the signal period T. Further, start counting at the rising edge of the second signal output by the torque sensor, and stop counting at the rising edge of the first signal output by the torque sensor. The measured time length is τ, and the phase difference between the two signals is Δφ=2π×(τ / T). When the measured shaft rotates without loading, the measured phase difference is Δφ0. When the measured shaft (1) rotates under loading, the measured phase difference is Δφ1.

[0087] The torque measurement method based on magnetic field sensing is to calculate the effective phase difference φ according to the formula φ=Δφ1-Δφ0; and calculate the torque M of the measured shaft (1) according to the following formula.

[0088]

[0089] Where M is the torque of the measured shaft, m is the number of teeth of the signal gear, L is the center distance between the two signal gears, r is the radius of the measured shaft, G is the shear elastic modulus of the measured shaft, and φ is the effective phase difference φ.

[0090] Beneficial effects:

[0091] 1. The present invention adopts torque measurement based on magnetic field sensing, which overcomes the defects of the influence of light pollution in the photoelectric method and the influence of the rotation speed on the signal amplitude in the magnetoelectric method. It can realize torque measurement under medium and low speed conditions in a relatively harsh environment at a relatively low cost. At the same time, the torque measurement based on magnetic field sensing of the present invention is also suitable for torque measurement under medium and high speeds, and has a wide speed adaptation range.

[0092] 2. The present invention adopts a signal conditioning circuit with an amplitude adaptive shaping function, which can greatly reduce the phase error caused by signal trigger shaping, thereby reducing the installation accuracy requirements for the torque sensor, improving the accuracy and convenience of torque measurement, and broadening the application scenarios of the present invention.

[0093] The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art may make various modifications or equivalent substitutions to the present invention within the essence and protection scope of the present invention, and such modifications or equivalent substitutions shall also be deemed to fall within the protection scope of the present invention.

Claims

1. A torque measurement device based on magnetic field sensing, characterized in that: The torque measurement device based on magnetic field sensing comprises: A measured axis (1); A first signal gear (2A) sleeved on one end of the measured shaft (1); a second signal gear (2B) sleeved on the other end of the measured shaft (1), with a predetermined length interval (L) being left between the first signal gear (2A) and the second signal gear (2B); a first torque sensor (3A) for detecting a first signal generated by the first signal gear (2A); a second torque sensor (3B), used for detecting the second signal generated by the second signal gear (2B); a phase difference measurement module (4), which is electrically connected to the first torque sensor (3A) and the second torque sensor (3B) respectively; An output module (5) is electrically connected to the phase difference measurement module (4).

2. The torque measurement device based on magnetic field sensing according to claim 1, characterized in that: The first signal gear (2A) is made of ferromagnetic material, and its tooth shape is rectangular, involute, or polygonal.

3. The torque measuring device based on magnetic field sensing according to claim 2, characterized in that: The first torque sensor (3A) comprises: a sensor housing (34) having an interior cavity; a magnetic sensor (31) disposed in the inner cavity; a permanent magnet (32) disposed in the inner cavity; A signal conditioning circuit (33) is also disposed in the interior cavity.

4. The torque measuring device based on magnetic field sensing according to claim 3 is characterized in that: The magnetic sensor (31) is an integrated magnetic field sensor, and the magnetic sensor (31) is a Hall sensor, or a magnetoresistive sensor, or a tunnel magnetoresistive sensor.

5. The torque measuring device based on magnetic field sensing according to claim 4, characterized in that: The first torque sensor (3A) and the second torque sensor (3B) are on the same straight line.

6. The torque measurement device based on magnetic field sensing according to claim 5, characterized in that: The distance between the first torque sensor (3A) and the first signal gear (2A) is smaller than the distance between the second torque sensor (3B) and the second signal gear (2B).

7. The torque measurement device based on magnetic field sensing according to claim 6, characterized in that: The first torque sensor (3A) and the second torque sensor (3B) have the same magnetic field sensitive direction.

8. The torque measurement device based on magnetic field sensing according to claim 7, characterized in that: The magnetic pole of the permanent magnet (32) points to the first signal gear (2A), and the magnetic pole includes an N pole or an S pole; the shape of the permanent magnet (32) is a cylinder.

9. The torque measurement device based on magnetic field sensing according to claim 8, characterized in that: The signal conditioning circuit (33) comprises an isolation protection module, a voltage control amplification module, a secondary amplification module, an amplitude detection module, and an amplitude adaptive shaping module.

10. A torque measurement method based on magnetic field sensing, characterized in that: Based on the torque measurement device based on magnetic field sensing according to any one of claims 1 to 9, the measurement method comprises: Obtaining a zero-point phase difference when not loaded, wherein the measured shaft (1) rotates when not loaded, and a first signal and a second signal output by the first torque sensor (3A) and the second torque sensor (3B) pass through the phase difference measurement module (4), and a phase difference between the two signals is Δφ0; Obtaining a working phase difference when loaded, wherein the measured shaft (1) rotates when loaded, and a first signal and a second signal output by the first torque sensor (3A) and the second torque sensor (3B) pass through a phase difference measurement module (4), and a phase difference of Δφ1 is obtained between the two signals; The output phase difference is calculated based on the phase differences Δφ0 and Δφ1.

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