Eddy current phase difference type rotating shaft torque measuring device and torque measuring method thereof

Abstract

The invention provides an eddy current phase difference type rotating shaft torque measuring device and a torque measuring method thereof. The eddy current phase difference type rotating shaft torque measuring device comprises a first signal gear, a second signal gear, a first eddy current sensor, a second eddy current sensor and a phase difference measuring module, the second signal gear and the first signal gear are sleeved on a detected rotating shaft according to a preset gear phase difference value; measuring the first signal gear to obtain a first signal; measuring the second signal gear to obtain a second signal; the phase difference measurement module is electrically connected with the first eddy current sensor and the second eddy current sensor so as to measure the first signal and the second signal, and then the first signal and the second signal are processed and calculated to output a torque value. The phase difference measurement module calculates the output torque value through eddy currents of different gears, and the technical problem that a rotating shaft torque measurement device which is low in measurement environment requirement and relatively simple in structure is lacked in the prior art is solved.

Description

Technical field:

[0001] The present invention relates to the field of testing technology, and in particular to an eddy current phase difference type shaft torque measuring device and a torque measuring method thereof. Background technology:

[0002] The research on shaft torque measurement has always been a focus of attention in the field of metrology and testing at home and abroad. Torque detection is an important means of mechanical transmission system performance evaluation, electromechanical equipment status monitoring and fault diagnosis, and electromechanical equipment intelligent control.

[0003] The main methods for measuring shaft torque include strain type, magnetoelasticity and angle type. As the most basic and classic 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. Although the emergence of strain type non-contact torque sensors with wireless power supply in recent years has facilitated the installation and use of sensors, its data transmission and anti-interference problems still need to be improved. The structure of magnetoelastic sensors is relatively complex, and the on-site working conditions and environmental factors have a great influence on the performance of magnetic materials, which in turn 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 are mainly photoelectric and magnetoelectric. Photoelectric torque sensors are more sensitive to on-site light pollution and have more stringent requirements on the detection environment. Magnetoelectric torque sensors are based on the principle of electromagnetic induction. The output signal is weak at medium and low speeds, and an auxiliary motor is often required to drive the magnetized component of the sensor to rotate. This not only increases the complexity and cost of the sensor and reduces its reliability, but also makes the sensor extremely bulky and difficult to use in mechanical transmission systems with limited structural space.

[0004] There is an urgent need for an eddy current phase difference type shaft torque measurement device and a torque measurement method thereof, which can help solve the technical problem in the prior art of lacking a shaft torque measurement device with low measurement environment requirements and relatively simple structure. Summary of the invention:

[0005] In one embodiment, the present invention provides an eddy current phase difference type shaft torque measurement device, which calculates the output torque value through the phase difference measurement module of the eddy currents of different gears, which helps to solve the technical problem in the prior art of lacking a shaft torque measurement device with low measurement environment requirements and relatively simple structure.

[0006] The eddy current phase difference type shaft torque measuring device comprises a first signal gear and a second signal gear, a first eddy current sensor, a second eddy current sensor, and a phase difference measuring module;

[0007] The second signal gear and the first signal gear are sleeved on the measured rotating shaft according to a predetermined gear phase difference;

[0008] The first eddy current sensor is used to measure the first signal gear to obtain a first signal;

[0009] The second eddy current sensor is used to measure the second signal gear to obtain a second signal;

[0010] The phase difference measurement module is electrically connected to the first eddy current sensor and the second eddy current sensor to measure the first signal and the second signal and then process and calculate an output torque value.

[0011] In one embodiment, the eddy current phase difference type shaft torque measurement device further includes a first signal conditioning module and a second signal conditioning module;

[0012] The first signal conditioning module is connected in series between the first eddy current sensor and the phase difference measurement module;

[0013] The second signal conditioning module is connected in series between the second eddy current sensor and the phase difference measurement module.

[0014] In one embodiment, the tooth shape of the first signal gear is rectangular, and the tooth widths of the tooth grooves are equal.

[0015] In one embodiment, the first eddy current sensor includes a sensor housing and a receiving coil, and a reference coil;

[0016] The sensor housing has an internal cavity;

[0017] The receiving coil is disposed in the internal cavity;

[0018] The reference coil is placed in the internal cavity, and the receiving coil and the reference coil are hollow cylindrical coils.

[0019] In one embodiment, the receiving coil and the reference coil have the same geometric size parameters and number of turns.

[0020] In one embodiment, during testing, the distance between the receiving coil and the first signal gear is smaller than the distance between the reference coil and the first signal gear.

[0021] In one embodiment, the first signal conditioning module includes an excitation signal, a phase shifter, a differential amplifier, a voltage-controlled amplifier, a phase-locked amplifier, a low-pass filter, an amplitude detection and a shaping circuit.

[0022] In one embodiment, the first eddy current sensor includes a first additional resistor and a second additional resistor;

[0023] A first end of the first additional resistor is electrically connected to one end of the receiving coil;

[0024] The third end of the second additional resistor is electrically connected to one end of the reference coil, and the fourth end of the second additional resistor is electrically connected to the second end of the first additional resistor;

[0025] The other end of the receiving coil is electrically connected to the other end of the reference coil.

[0026] In one embodiment, the signal between the first additional resistor and the receiving coil, and the signal between the second additional resistor and the reference coil are used for differential amplification;

[0027] A signal between the first additional resistor and the second additional resistor, and a signal between the receiving coil and the reference coil are used as an excitation signal.

[0028] In one embodiment, the present invention further provides an eddy current phase difference type shaft torque measurement method. Based on the eddy current phase difference type shaft torque measurement device, the eddy current phase difference type shaft torque measurement method includes:

[0029] Obtaining the zero-point phase difference φ0 when not loaded, the measured shaft rotates without loading torque, and the first signal and the second signal at this time pass through the phase difference measurement module to obtain a phase difference of φ0 between the two signals;

[0030] Obtaining the working phase difference φ1 during loading, the measured shaft rotates under the condition of loading torque, the first signal and the second signal at this time pass through the phase difference measurement module, and the phase difference of the two signals is φ1;

[0031] The shaft torque is calculated and output according to the zero-point phase difference φ0 and the working phase difference φ1. Description of the drawings:

[0032] Figure 1 Schematic diagram of the measurement principle in one embodiment of the present invention;

[0033] Figure 2 Schematic diagram of the system composition of an eddy current phase difference type shaft torque measurement device in another embodiment of the present invention;

[0034] Figure 3 It is a schematic diagram of the sensor layout of an eddy current phase difference type shaft torque measurement device in another embodiment of the present invention;

[0035] Figure 4 It is a schematic diagram of the structure of the eddy current sensor signal conditioning module in another embodiment of the present invention;

[0036] Figure 5It is a schematic diagram of connecting an eddy current sensor and a signal conditioning module in another embodiment of the present invention;

[0037] Figure 6 Schematic diagram of signal conditioning waveforms during eddy current phase difference shaft torque measurement in another embodiment of the present invention.

[0038] Reference numerals:

[0039] Tested shaft 1

[0040] First signal gear 2A

[0041] Second signal gear 2B

[0042] First eddy current sensor 3A

[0043] Receiving coil 31

[0044] Reference coil 32

[0045] Sensor housing 33

[0046] The first additional resistor 34

[0047] First End 341

[0048] Second end 342

[0049] The second additional resistor 35

[0050] The third end 351

[0051] Fourth End 352

[0052] Second eddy current sensor 3B

[0053] First signal conditioning module 4A

[0054] Second signal conditioning module 4B

[0055] Phase difference measurement module 5 Specific embodiment:

[0056] 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.

[0057] Various aspects and features of the present application are described herein with reference to the accompanying drawings.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] Figure 1 Schematic diagram of the measurement principle in one embodiment of the present invention; Figure 2 Schematic diagram of the system composition of an eddy current phase difference type shaft torque measurement device in another embodiment of the present invention; Figure 3 It is a schematic diagram of the sensor layout of an eddy current phase difference type shaft torque measurement device in another embodiment of the present invention; Figure 4 It is a schematic diagram of the structure of the eddy current sensor signal conditioning module in another embodiment of the present invention; Figure 5 It is a schematic diagram of connecting an eddy current sensor and a signal conditioning module in another embodiment of the present invention; Figure 6 Schematic diagram of signal conditioning waveforms during eddy current phase difference shaft torque measurement in another embodiment of the present invention.

[0064] like Figures 1 to 6 As shown, in one embodiment, the present invention provides an eddy current phase difference type shaft torque measuring device, the eddy current phase difference type shaft torque measuring device comprising a first signal gear 2A and a second signal gear 2B, a first eddy current sensor 3A, a second eddy current sensor 3B, and a phase difference measuring module 5;

[0065] The second signal gear 2B and the first signal gear 2A are sleeved on the measured rotating shaft 1 according to a predetermined gear phase difference;

[0066] A first eddy current sensor 3A, which is used to measure the first signal gear 2A to obtain a first signal;

[0067] A second eddy current sensor 3B, which is used to measure the second signal gear 2B to obtain a second signal;

[0068] The phase difference measurement module 5 is electrically connected to the first eddy current sensor 3A and the second eddy current sensor 3B to measure the first signal and the second signal and then process and calculate the output torque value.

[0069] like Figure 1 As shown, the first signal gear 2A and the second signal gear 2B are arranged axially opposite to each other along the measured rotating shaft 1, and the two signal gears are separated by a certain distance L. The eddy current sensor corresponds to the signal gears one by one, and the first signal and the second signal are measured by the phase difference measurement module 5 to obtain the phase difference and process and calculate the output torque value, which helps to solve the technical problem of the lack of a rotating shaft torque measurement device with low measurement environment requirements and relatively simple structure in the prior art.

[0070] In one embodiment, the eddy current phase difference type shaft torque measurement device further includes a first signal conditioning module 4A and a second signal conditioning module 4B;

[0071] The first signal conditioning module 4A is connected in series between the first eddy current sensor 3A and the phase difference measurement module 5;

[0072] The second signal conditioning module 4B is connected in series between the second eddy current sensor 3B and the phase difference measurement module 5 .

[0073] In one embodiment, the signal gear is made of metal material, including ferromagnetic metal material and non-ferromagnetic metal material. The tooth shape of the first signal gear 2A is rectangular, and the tooth widths of the teeth are equal. The second signal gear 2B adopts the same material and structure.

[0074] In one embodiment, the first eddy current sensor 3A includes a sensor housing 33, a receiving coil 31, and a reference coil 32;

[0075] The sensor housing 33 has an internal cavity;

[0076] The receiving coil 31 is placed in the internal cavity;

[0077] The reference coil 32 is placed in the internal cavity, and the receiving coil 31 and the reference coil 32 are hollow cylindrical coils. The first eddy current sensor 3A and the second eddy current sensor 3B may have the same structure.

[0078] In one embodiment, the receiving coil 31 and the reference coil 32 have the same geometrical size parameters and number of turns.

[0079] In one embodiment, during testing, the distance between the receiving coil 31 and the first signal gear 2A is smaller than the distance between the reference coil 32 and the first signal gear 2A. The receiving coil 31 and the reference coil 32 are coaxially arranged front and back, and their axial direction is the same as the radial direction of the signal gear 2.

[0080] In one embodiment, the first signal conditioning module 4A includes an excitation signal, a phase shifter, a differential amplifier, a voltage-controlled amplifier, a phase-locked amplifier, a low-pass filter, an amplitude detection and a shaping circuit.

[0081] In this embodiment, a specific implementation method for subsequent processing of the first signal or the second signal collected by the eddy current sensor is provided. The first signal conditioning module 4A and the second signal conditioning module 4B may have the same structure.

[0082] The first signal or the second signal is subjected to differential amplification, voltage-controlled amplification, phase-locked amplification, and low-pass filtering in sequence, and then output through a shaping circuit, amplitude detection is realized during the low-pass filtering process, and then fed back to the voltage-controlled amplification, one side of the excitation signal is fed back to the eddy current sensor, and the other side of the excitation signal is used in the phase-locked amplification process through a phase shifter.

[0083] In one embodiment, the first eddy current sensor 3A includes a first additional resistor 33 and a second additional resistor 34;

[0084] A first end 341 of the first additional resistor 34 is electrically connected to one end of the receiving coil 31;

[0085] The third end 351 of the second additional resistor 35 is electrically connected to one end of the reference coil 32 , and the fourth end 352 of the second additional resistor 35 is electrically connected to the second end 342 of the first additional resistor 33 ;

[0086] The other end of the receiving coil 31 is electrically connected to the other end of the reference coil 32 .

[0087] The signal conditioning module 4 and the eddy current sensor form a bridge measurement circuit. The first additional resistor 33 is connected in series with the receiving coil 31, the second additional resistor 34 is connected in series with the reference coil 32, and then the two branches are connected in parallel, one end of the excitation signal is connected to the common connection end of the bridge additional resistors R1 and R2, that is, the first additional resistor 33 and the second additional resistor 34, and the other end of the excitation signal is connected to the common connection end of the receiving coil 31 and the reference coil 32. The common connection end of the first additional resistor 33 and the receiving coil 31 is connected to the differential amplifier positive input end of the signal conditioning module, and the common connection end of the second additional resistor 34 and the reference coil 32 is connected to the differential amplifier negative input end of the signal conditioning module.

[0088] The common connection end of the receiving coil 31 and the reference coil 32 of the eddy current sensor is a same-name end, and one end of the receiving coil 31 connected to the first additional resistor 33 and one end of the reference coil 32 connected to the second additional resistor 34 are same-name ends.

[0089] In one embodiment, the signal between the first additional resistor 33 and the receiving coil 31 , and the signal between the second additional resistor 34 and the reference coil 32 are used for differential amplification;

[0090] The signal between the first additional resistor 33 and the second additional resistor 34 and the signal between the receiving coil 31 and the reference coil 32 are used as excitation signals.

[0091] The signal conditioning module has the function of adaptive amplitude amplification and shaping. The eddy current sensor is output through the bridge circuit and then enters the differential amplifier for amplification, and then undergoes voltage-controlled amplification, phase-locked amplification and low-pass filtering. On the one hand, the output of the low-pass filter is shaped into a square wave signal through the shaping circuit, and on the other hand, a feedback voltage is output after amplitude detection to automatically adjust the amplification factor of the voltage-controlled amplification. This makes the signal entering the phase-locked amplifier a signal with a relatively stable amplitude. The reference signal of the phase-locked amplifier comes from the output of the excitation signal after phase shifting, and the output signal of the voltage-controlled amplification has the same phase as the output signal of the phase shifter.

[0092] In one embodiment, the present invention further provides an eddy current phase difference type shaft torque measurement method. Based on the eddy current phase difference type shaft torque measurement device, the eddy current phase difference type shaft torque measurement method includes:

[0093] The first step is to install the measuring device: select two measuring points with an axial distance L on the measured shaft 1, install and tighten the signal gear; fix an eddy current sensor opposite the middle of each signal gear, connect the two eddy current sensors to the signal conditioning module, and connect the outputs of the two signal conditioning modules to the phase difference measurement module.

[0094] The second step is to obtain the zero-point phase difference φ0 when there is no load. The measured shaft 1 rotates without loading torque. At this time, the first signal and the second signal pass through the phase difference measurement module 5, and the phase difference between the two signals is φ0;

[0095] The third step is to obtain the working phase difference φ1 during loading. The measured shaft 1 rotates under the condition of loading torque. The first signal and the second signal at this time pass through the phase difference measurement module 5, and the phase difference between the two signals is φ1.

[0096] The shaft torque is calculated and output according to the zero-point phase difference φ0 and the working phase difference φ1.

[0097] In one embodiment, the phase difference is measured by FPGA using a pulse counting method, such as Figure 6 , start counting at the rising edge of the first signal S4A output by the signal conditioning circuit, stop counting at the next rising edge, and obtain the signal period T. Further, start counting at the rising edge of the first signal S4A output by the signal conditioning circuit, stop counting at the rising edge of the second signal S4B, the measured time length is τ, and the phase difference between the two signals is 2π×(τ / T). The measured shaft rotates without loading, and the measured phase difference is the zero-point phase difference φ0. The measured shaft rotates under loading, and the measured phase difference is the working phase difference φ1.

[0098] Based on the eddy current phase difference torque measurement method, the effective phase difference φ is calculated according to the formula φ=φ1-φ0; the torque M of the measured shaft is calculated according to the following formula.

[0099] According to the formula φ=φ1-φ0, the effective phase difference φ is calculated; and the torque M of the measured rotating shaft 1 is calculated according to the following formula.

[0100]

[0101] Wherein, M is the torque of the measured rotating shaft 1, m is the number of teeth of the signal gear, L is the center distance between the two signal gears, d is the diameter of the measured rotating shaft 1, G is the shear elastic modulus of the measured rotating shaft 1, and φ is the effective phase difference.

[0102] The present invention has the following beneficial effects:

[0103] 1. The present invention adopts eddy current sensor to measure the torque of rotating shaft, which overcomes the disadvantages of light pollution in photoelectric sensor and the influence of rotation speed on signal amplitude in magnetoelectric sensor, and can realize torque measurement under medium and low rotation speed conditions in harsh environment at low cost. The present invention combines phase-locked amplification and voltage-controlled amplification technology to condition the eddy current sensor signal, and the detection device has the advantages of non-contact, no wear and strong anti-interference ability.

[0104] 2. The present invention uses voltage-controlled amplification to condition the signal of the eddy current sensor. When the installation distance between the eddy current sensor and the signal gear is close, the signal is strong, and the voltage-controlled amplifier has a smaller amplification factor; when the installation distance between the eddy current sensor and the signal gear is far, the signal is weak, and the voltage-controlled amplifier has a larger amplification factor. In this way, the signal entering the phase-locked amplifier is always maintained with a strong amplitude, which can greatly reduce the phase measurement error caused by the subsequent shaping circuit, and can also reduce the accuracy requirements for the installation of the eddy current sensor.

[0105] The measurement principle diagram of the present invention shows that two signal gears are installed at two measuring points on the rotating shaft at a distance of L. When the shaft rotates with a certain torque load, the signal gear will also produce relative torsion following the shaft section where the measuring point is located. When no torque is applied, the relative torsional deformation angle θ generated by points A and B on the same generatrix after the torque M is applied is:

[0106] θ=ML / GI

[0107] Where I is the polar moment of inertia of the measured shaft section, d is the diameter of the shaft; M is the torque load; G is the shear elastic modulus of the shaft.

[0108] The relative torsional deformation angle can also be written as:

[0109]

[0110] Phase difference of the periodic signal generated by the signal gear The relationship between the relative torsion angle θ is:

[0111]

[0112] Where m is the number of teeth on the signal gear. Further, the torque load M can be expressed as:

[0113]

[0114] Therefore, the torque load M can be indirectly tested by testing the effective phase difference of the periodic signals generated by the two signal gears.

[0115] Under the guidance of this principle, Figure 2 The system composition diagram of the eddy current phase difference type shaft torque measuring device is given. It includes a measured shaft, a signal gear, an eddy current sensor, a signal conditioning module and a phase difference measurement module. The signal gear includes a first signal gear and a second signal gear, which are arranged opposite to each other along the axial direction of the measured shaft, and the two signal gears are a certain distance L apart; the eddy current sensor includes a first eddy current sensor and a second eddy current sensor; the eddy current sensors correspond to the signal gears one by one, and one eddy current sensor is fixed to each signal gear; the first eddy current sensor and the second eddy current sensor correspond to the first signal and the second signal respectively; the first signal and the second signal are measured by the phase difference measurement module to obtain the phase difference and process and calculate the output torque value.

[0116] In one embodiment, the diameter of the measured rotating shaft is 178 mm, the material of the signal gear is 45# steel, the tooth shape is rectangular, the module is 3, and the number of teeth is 80.

[0117] The eddy current sensor includes a receiving coil and a reference coil. The shape of the eddy current sensor is a hollow cylindrical coil. The receiving coil and the reference coil have the same geometric size parameters and number of turns. In one embodiment, the inner diameter of the coil is 3 mm, the outer diameter is 6 mm, the height is 3 mm, and the number of turns is 105 turns. The receiving coil and the reference coil are coaxially arranged front and back, and the spacing between them is 5 mm.

[0118] The signal conditioning module includes: excitation signal, phase shifter, differential amplifier, voltage-controlled amplifier, phase-locked amplifier, low-pass filter, amplitude detection and shaping circuit. In one embodiment, the excitation signal is a 200kHz sine wave, and the speed of the measured shaft is 300 rpm. The voltage-controlled amplifier module uses a VCA810 voltage-controlled gain amplifier, and its voltage-controlled gain ranges from -40 to 40dB.

[0119] The signal conditioning module and the eddy current sensor form a bridge measurement circuit. The additional resistor R1 is connected in series with the receiving coil, the additional resistor R2 is connected in series with the reference coil, and then the two branches are connected in parallel. One end of the excitation signal is connected to the common connection end of the bridge additional resistors R1 and R2, and the other end of the excitation signal is connected to the common connection end of the receiving coil and the reference coil. The common connection end of the additional resistor R1 and the receiving coil is connected to the differential amplifier positive input end of the signal conditioning module, and the common connection end of the additional resistor R2 and the reference coil is connected to the differential amplifier negative input end of the signal conditioning module. In one embodiment, the nominal resistance of the additional resistors R1 and R2 is 100 ohms, and the differential amplifier module adopts an AD8421 instrument amplifier.

[0120] The signal conditioning module has the function of adaptive amplitude amplification and shaping. The eddy current sensor is output through the bridge circuit and then enters the differential amplifier for amplification, and then undergoes voltage-controlled amplification, phase-locked amplification and low-pass filtering. In one embodiment, the waveform diagram of the signal conditioning process is as follows Figure 6 As shown. The differentially amplified output signal S2 has the same main frequency component as the excitation signal S1, and its envelope frequency is the same as the periodic signal frequency generated by the signal gear. The differentially amplified signal is phase-locked amplified and low-pass filtered to obtain the S3 signal, which represents the periodic signal generated by the rotation of the signal gear. The low-pass filtered output signals corresponding to the two gears have the same frequency, but there is a certain phase difference.

[0121] 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. An eddy current phase difference type shaft torque measuring device, characterized in that: The eddy current phase difference type shaft torque measuring device comprises: a first signal gear (2A); a second signal gear (2B), the second signal gear (2B) and the first signal gear (2A) being sleeved on the measured rotating shaft (1) according to a predetermined gear phase difference; a first eddy current sensor (3A), used for measuring the first signal gear (2A) to obtain a first signal; a second eddy current sensor (3B), used for measuring the second signal gear (2B) to obtain a second signal; A phase difference measurement module (5) is electrically connected to the first eddy current sensor (3A) and the second eddy current sensor (3B) to measure the first signal and the second signal and then process and calculate an output torque value.

2. The eddy current phase difference type shaft torque measuring device according to claim 1, characterized in that: The eddy current phase difference type shaft torque measuring device also includes: a first signal conditioning module (4A) connected in series between the first eddy current sensor (3A) and the phase difference measurement module (5); A second signal conditioning module (4B) is connected in series between the second eddy current sensor (3B) and the phase difference measurement module (5).

3. The eddy current phase difference type shaft torque measuring device according to claim 2, characterized in that: The tooth shape of the first signal gear (2A) is rectangular, and the tooth widths of the tooth grooves are equal.

4. The eddy current phase difference type shaft torque measuring device according to claim 3, characterized in that: The first eddy current sensor (3A) comprises: a sensor housing (33) having an internal cavity; a receiving coil (31) disposed in the internal cavity; A reference coil (32) is placed in the internal cavity. The receiving coil (31) and the reference coil (32) are hollow cylindrical coils.

5. The eddy current phase difference type shaft torque measuring device according to claim 4, characterized in that: The receiving coil (31) and the reference coil (32) have the same geometrical dimension parameters and number of turns.

6. The eddy current phase difference type shaft torque measuring device according to claim 5, characterized in that: During testing, the distance between the receiving coil (31) and the first signal gear (2A) is smaller than the distance between the reference coil (32) and the first signal gear (2A).

7. The eddy current phase difference type shaft torque measuring device according to claim 6, characterized in that: The first signal conditioning module (4A) comprises an excitation signal, a phase shifter, a differential amplifier, a voltage-controlled amplifier, a phase-locked amplifier, a low-pass filter, an amplitude detection and a shaping circuit.

8. The eddy current phase difference type shaft torque measuring device according to claim 7, characterized in that: The first eddy current sensor (3A) comprises: a first additional resistor (34), a first end (341) of which is electrically connected to one end of the receiving coil (31); a second additional resistor (35), a third end (351) of which is electrically connected to one end of the reference coil (32), and a fourth end (352) of the second additional resistor (35) is electrically connected to the second end (342) of the first additional resistor (34); The other end of the receiving coil (31) is electrically connected to the other end of the reference coil (32).

9. The eddy current phase difference type shaft torque measuring device according to claim 8, characterized in that: The signal between the first additional resistor (33) and the receiving coil (31), and the signal between the second additional resistor (34) and the reference coil (32) are used for differential amplification; The signal between the first additional resistor (33) and the second additional resistor (34), and the signal between the receiving coil (31) and the reference coil (32) are used as excitation signals.

10. An eddy current phase difference type shaft torque measurement method, characterized in that: Based on the eddy current phase difference type shaft torque measurement device according to any one of claims 2 to 9, the eddy current phase difference type shaft torque measurement method comprises: Obtaining a zero-point phase difference φ0 when not loaded, the measured rotating shaft (1) rotates without loading torque, and at this time, the first signal and the second signal pass through a phase difference measurement module (5), and the phase difference of the two signals is φ0; Obtaining a working phase difference φ1 during loading, the measured rotating shaft (1) rotates under a loaded torque, and the first signal and the second signal at this time pass through a phase difference measurement module (5), and the phase difference between the two signals is φ1; The shaft torque is calculated and output according to the zero-point phase difference φ0 and the working phase difference φ1.

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