A solid shaft thrust and torque measuring device

Abstract

The application provides a solid shaft thrust and torque measuring device, which comprises a left clamping ring and a right clamping ring movably installed on the surface of a solid shaft, four groups of measuring arms are uniformly arranged on the same circumference between the left clamping ring and the right clamping ring, the measuring arms comprise left measuring arms and right measuring arms, a laser and a rotating mirror are arranged in the left measuring arms, the right measuring arms are provided with four-quadrant detectors capable of adjusting distance, the solid shaft thrust is measured by using laser self-mixing interference, and the solid shaft torque is measured by using the four-quadrant detectors. The application measures the deformation of the solid shaft caused by the thrust and torque by using the laser self-mixing interference technology, and finally calculates the thrust and torque through the displacement of the deformation.

Description

TECHNICAL FIELD

[0001] The present application relates to an optical sensor and a laser self-mixing interference device, in particular to a solid shaft thrust and torque measuring device. BACKGROUND

[0002] On many power machines and transport machines, such as motors, fans, water pumps, hydraulic pumps, gearboxes, automobile drive shafts, solid propulsion shafts, and oil drilling rigs, the rotational torque on the drive shaft is an extremely important parameter in the entire power system. There are many technologies on the market to measure the thrust and torque of the solid shaft, for example: 1. By directly measuring the deformation of the shaft system to measure the thrust and torque, including a thrust measuring component and a torque measuring component. The thrust measuring component is a square block, and the sensor deforms when subjected to thrust. The torque measuring component is a thin sheet composed of a through circular hole and two semicircular through holes on the shaft, and the sheet deforms when the sensor is subjected to torque. 2. By pasting strain gauges on the surface of the thrust measuring component and the torque measuring component, the deformation of the strain gauges can be measured to obtain the size of the thrust or torque. When the elastic shaft is subjected to torque and produces a small deformation, the change of the bridge resistance value is converted into the change of the voltage signal, thereby realizing torque measurement. 3. Optoelectronic measurement, by shining a laser on a four-quadrant sensor, the change in displacement will cause the output voltage signal to change, thereby measuring the displacement. As shown in the four-quadrant sensor, the signal is collected by a data acquisition card, the collected signal is processed, and the time domain and frequency domain characteristics of the laser SMI signal are analyzed. The four-quadrant photoelectric detector is a photoelectric detector device composed of four photoelectric diodes with the same performance arranged according to the Cartesian coordinate requirement. The amplification circuit of the four-quadrant detector has a current-to-voltage amplifier, which can provide a difference signal of bottom minus top and left minus right. Figure 1

[0003] Reference: 1. Song Lei, Ren Zaimei, Chen Lin, Jianglong Chen, Cheng Ersheng. Design and Research of a Marine Thrust and Torque Sensor [J]. Ship Science and Technology, 2020, 42(13): 82-85.2.

[0004] 2. Zhang Ziyin, Lu Wenke, Zuo Feng, Ding Yong. Temperature compensation of strain gauge type torque sensor based on piecewise linear interpolation method [J]. Electronic Measurement Technology, 2022, 45(08): 143-147.

[0005] 3. VAF Instruments, T-sense shaft power torque meter.

[0006] 4. CN202211243079 - A marine thrust and torque comprehensive monitoring device and method, China Shipbuilding Industry Corporation 704th Research Institute, torque measurement is realized by strain gauges. ​

[0007] Compared with the other two kinds of shaft contact type measurement, the photoelectric type measurement is a non-contact type with higher measurement accuracy. The generation of torque will affect the measurement of thrust by using a four-quadrant sensor.

[0008] Currently, there is no method for measuring the thrust of a solid shaft using laser self-mixing interference technology at the social level, such as Figure 2 As shown, the laser self-mixing interference effect (Laser Self-mixing Interference Effect) refers to the phenomenon that the output light of a laser is partially reflected or scattered by an external object (Target) and then fed back into the resonant cavity of the laser. This feedback light, which carries information about the external object, interferes with the light inside the cavity, causing changes in the output power of the laser. Due to the similarity between the output signal and the traditional two-beam interference signal, it is called self-mixing interference. Among them, LD is the laser; PD is the photodiode integrated inside the laser; MI and M2 refer to the two faces of the LD laser; M3 refers to the measurement object, which is currently the surface of the four-quadrant detector. SUMMARY

[0009] The purpose of the present application is to provide a solid shaft thrust and torque measurement device to solve the problem of measuring the thrust and torque of a solid shaft. The technical solution is as follows:

[0010] A solid shaft thrust and torque measurement device, comprising a left clasp and a right clasp mounted movably on the surface of a solid shaft, four groups of measurement arms uniformly arranged on the same circumference are installed between the left clasp and the right clasp, the measurement arms include left measurement arms and right measurement arms, the left measurement arms are provided with lasers and rotating mirrors, the right measurement arms are provided with four-quadrant detectors capable of adjusting the distance, the solid shaft thrust is measured by laser self-mixing interference, and the solid shaft torque is measured by the four-quadrant detectors.

[0011] The left clasp and the right clasp are the same in size, shape and material, and are composed of two groups of half-round steel rings. The upper and lower ends of the steel ring are provided with fixed plates, and the fixed plates are fixedly connected by clasp nuts.

[0012] The left clasp and the right clasp are provided with mounting holes for mounting the measurement arms and wiring holes for connecting wires. The two ends of the measurement arm are provided with baffles, and the outer wall of the baffle is provided with a baffle hole corresponding to the mounting hole.

[0013] The left measurement arm is welded with an extension arm, the first circuit board is installed in the extension arm, the laser is arranged on the first circuit board, the rotating mirror is arranged at the other end of the extension arm in a threaded connection, the inner wall of the rotating mirror is provided with threads, the lens groove is arranged in the interior, and the convex lens is installed in the lens groove.

[0014] The first circuit board outer wall is provided with reinforcing holes, screws are mounted in the reinforcing holes, the first circuit board is fixedly connected with the left measuring arm through the screws, the screws and the reinforcing holes are provided with four groups, and are symmetrically distributed on the first circuit board outer wall.

[0015] The right measuring arm is provided with a telescopic arm, the telescopic arm is provided with a clamping groove, a second circuit board is mounted in the clamping groove, and the second circuit board is provided with a four-quadrant detector.

[0016] The left measuring arm and the right measuring arm are connected with a light shielding sleeve, the light shielding sleeve is made of black rubber and can be freely stretched and contracted.

[0017] The right measuring arm outer wall is provided with a fixing nut, the length of the telescopic arm in the right measuring arm is controlled through the fixing nut, a fine adjustment nut is movably mounted on the telescopic arm outer wall, the fine adjustment nut is provided with four groups, the position of the second circuit board is controlled, and the laser of the laser device can be more collimated to hit the center position of the photoelectric sensor on the second circuit board.

[0018] The solid shaft is deformed under the thrust, the left measuring arm and the right measuring arm mounted on the solid shaft are relatively displaced in the X direction, the laser emitted by the laser device in the left measuring arm hits the four-quadrant photoelectric detector of the right measuring arm, the light beam is reflected on the surface of the four-quadrant photoelectric detector back to the inside of the laser cavity, interference is generated with the light beam emitted by itself, the interference signal current is output through the PD pin of the laser device, is amplified through the first circuit board, and is finally output through the first signal line for operation, so that the thrust received by the solid shaft is interpreted, the thrust and the deformation of the solid shaft satisfy the Hook's law, and the relationship between the deformation displacement D and the number N of interference fringes and the wavelength λ is represented as:

[0019]

[0020] According to the Hook's law F=KX, the thrust T can be represented as Wherein K is a constant.

[0021] When the solid shaft is affected by the torque, X direction and Y direction displacements are generated, the deformation of the torque to the solid shaft is linear, the laser emitted by the laser in the left measuring arm is on the four-quadrant photoelectric detector of the right measuring arm, the four quadrants of the four-quadrant photoelectric detector output different currents, the size of the torque is solved by tracking the track of the center of the light spot, the current output by each quadrant of the four-quadrant detector is converted into voltage, X represents the voltage difference of the top two quadrants minus the bottom two quadrants, Y represents the voltage difference of the left two quadrants minus the right two quadrants, according to the displacement change of the light spot on the four-quadrant, the displacement change of the light spot center in X and Y directions is (Delta x, Delta y), since the deformation of the torque to the solid shaft has X axis and Y axis changes, according to the Hook's law, the displacement L of the torque to the solid shaft within the rigidity range of the material is:

[0022]

[0023] Wherein, Delta X and Delta Y are the displacements of the center of the light spot moving in X axis and Y axis, the torque M calculated according to the torque of the bearing is:

[0024]

[0025] Wherein, G is the shear modulus, I P is the moment of inertia, Delta L is the distance between the clamps, all of which are constants, then the torque coefficient K M is a constant.

[0026] The beneficial effects of the present application are:

[0027] (1) The present application measures the deformation of the solid shaft affected by the thrust and torque through the laser self-mixing interference technology, and finally calculates the thrust and torque through the displacement of the deformation. Since the deformation of the solid shaft affected by the thrust and torque is very small, the laser self-interference technology can achieve 1 / 2 wavelength accuracy, and the deformation of 317nm can be detected, which can meet the actual requirements of thrust torque measurement.

[0028] (2) The present application sets a rotating mirror at the left end of the right measuring arm, the rotating mirror is installed at the right end of the left measuring arm through a rotating thread, which is not only convenient to install, but also clamps a convex lens inside the rotating mirror, so that the light beam emitted by the laser is more collimated on the four-quadrant detector.

[0029] (3) The left measuring arm and the right measuring arm are connected through the light shielding sleeve, the light shielding sleeve is made of black rubber and can be freely stretched and contracted to ensure that the left and right measuring arms can be accurately installed in the left and right clamps; at the same time, the present application uses laser self-interference to measure displacement, which is very precise and sensitive to optical signals, and the setting of the light shielding sleeve ensures the normal measurement of the system and improves the measurement accuracy.

[0030] (4) The right measuring arm adopts telescopic arm, which can freely adjust the distance between the light source and the four-quadrant photoelectric detector, and meanwhile, the position of the second circuit board can be freely adjusted through the fine adjustment nut, so that the light beam emitted by the laser can be collimated and hit the center position of the four-quadrant photoelectric detector in the case that the measuring arm is at rest, and the measuring precision is improved.

[0031] (5) The left and right clamping rings are tightly fixed on the solid shaft, so that the loosening phenomenon does not occur when the solid shaft rotates, and the stability is ensured, then the four groups of measuring arms are uniformly installed in the left and right clamping rings, so that the installation problem is solved; meanwhile, the design of the four groups of measuring arms ensures the measuring precision, and in the case that one group is damaged, normal work can be carried out. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic view of the four-quadrant sensor;

[0033] Figure 2 is a schematic view of the laser self-mixing interference effect;

[0034] Figure 3 is a structural schematic view of the solid shaft thrust and torque measuring device;

[0035] Figure 4 is a main body schematic view of the measuring arm structure;

[0036] Figure 5 is a sectional view schematic view of the measuring arm;

[0037] Figure 6 is an internal plane enlarged view of the left measuring arm;

[0038] Figure 7 is an internal plane sectional view of the right measuring arm member;

[0039] Figure 8 is a main body structure schematic view of the rotating mirror;

[0040] Figure 9 is a plan view of the four-quadrant photoelectric detector;

[0041] Figure 10 is a schematic view of the laser diode LD;

[0042] Figure 11 is a working principle schematic view of the present application.

[0043] The following are the labels in the diagram: 1. Solid shaft; 2. Left retaining ring; 3. Fixing plate; 4. Retaining ring nut; 5. Mounting hole; 6. Wiring hole; 7. First signal line; 8. Right retaining ring; 9. Second signal line; 10. Measuring arm; 101. Left measuring arm; 102. Extended arm; 103. First baffle; 104. First baffle hole; 105. Light shield; 106. Telescopic arm; 107. Fine-tuning nut; 108. Right measuring arm; 109. Fixing screw 1010, Second baffle; 1011, Third outlet hole; 1012, Second baffle hole; 1013, First outlet hole; 1014, Second outlet hole; 201, First circuit board; 202, Laser; 203, Screw; 204, Convex lens; 205, Second circuit board; 206, Four-quadrant detector; 207, Slot; 208, Reinforcing hole; 209, Rotating mirror; 2010, Lens slot; 2011, Thread. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] like Figure 3 As shown, the device for measuring the thrust and torque of a solid shaft includes a left retaining ring 2 and a right retaining ring 8 movably mounted on the surface of a solid shaft 1. The left retaining ring 2 and right retaining ring 8 are identical in size, shape, and material. Four sets of measuring arms 10 are evenly arranged on the same circumference and installed between the left retaining ring 2 and right retaining ring 8. Since the measuring arms 10 cannot be stably mounted on the solid shaft 1, they are secured by the left retaining ring 2 and right retaining ring 8, ensuring stable measurement of the measuring arms 10. Thus, the four sets of measuring arms 10 are fixed to the solid shaft by the left retaining ring 2 and right retaining ring 8. The left retaining ring 2 or right retaining ring 8 is composed of two sets of semi-circular steel rings. Fixing plates 3 are provided at the upper and lower ends of the steel rings. The fixing plates 3 are threaded, and the two sets of fixing plates 3 are fixedly connected by retaining ring nuts 4. The fixing plates 3 secure the left retaining ring 2 and right retaining ring 8, preventing them from sliding on the solid shaft.

[0046] The positions of the left clasp 2 and the right clasp 8 on the solid shaft are selected based on the actual scene, finding a place where the solid shaft is free of obstacles. The distance between the two is determined by the lengths of the left and right measuring arms, ensuring that the distance between the LED and the four-quadrant detector is 3-5mm.

[0047] The left clasp 2 and the right clasp 8 are provided with a mounting hole 5 for fixing the mounting of the measuring arm 10 and a wire hole 6 for the connection of the wire, further, the wire hole 6 of the left clasp 2 is used for passing through the first signal wire 7, and the wire hole 6 of the right clasp 8 is used for passing through the second signal wire 9. The two mounting holes 5 and one wire hole 6 form a group of openings, and the outer wall of the left clasp 2 and the right clasp 8 is provided with four groups of openings.

[0048] As shown in Figure 4 and Figure 5 The measuring arm 10 includes a left measuring arm 101 and a right measuring arm 108, the left measuring arm 101 is welded with an extension arm 102, the right measuring arm 108 is provided with a telescopic arm 106, and a light shielding sleeve 105 is connected between the extension arm 102 and the telescopic arm 106, the two ends of the light shielding sleeve 105 and the extension arm 102 and the telescopic arm 106 are fixedly connected by adhesion, the light shielding sleeve 105 is made of black rubber and can freely stretch and retract. The measuring arm 10 measures the displacement by laser self-mixing interference, and the light shielding treatment is required during the measurement, the extension arm 102 and the telescopic arm 106 are connected by the light shielding sleeve 105, which not only ensures the interference quality, but also improves the measurement accuracy.

[0049] Therefore, the measuring arm 10 includes the left measuring arm 101, the extension arm 102, the light shielding sleeve 105, the telescopic arm 106 and the right measuring arm 108 connected in sequence. The first baffle 103 protruding from the outer wall of the left measuring arm 101 is fixedly connected with the left clasp 2, the outer wall of the first baffle 103 is provided with a first baffle hole 104 corresponding to the mounting hole 5, and the inside of the left measuring arm 101 is provided with a first wire outlet hole 1013 for passing through the first signal wire 7; the second baffle 1010 protruding from the outer wall of the right measuring arm 108 is fixedly connected with the right clasp 8, the outer wall of the second baffle 1010 is provided with a second baffle hole 1012 corresponding to the mounting hole 5, the second baffle hole 1012 is provided with two groups, and the inside of the right measuring arm 108 is provided with a third wire outlet hole 1011 for passing through the second signal wire 9. The mounting structure of the right measuring arm 108 is completely same as that of the left measuring arm 102, which is not only convenient for installation, but also convenient for disassembly and detection.

[0050] The inside of the extension arm 102 is provided with a first circuit board 201 fixedly connected with the left measuring arm 101, the first circuit board 201 is provided with a first sensor 202 and a second sensor 203 as shown in Figure 10The laser 202 shown is a semiconductor laser, model HL6320G, wavelength 635nm, the product laser can be self-mixing interference, and the intensity of the interference light is converted into current output through the pin, the laser 202 is connected with the first signal line 7. The other end of the lengthened arm 102 is provided with a threaded rotating mirror 209, the outer side of the rotating mirror 209 is bonded with a light shielding sleeve 105, combined with Figure 8 As shown, the inner wall of the rotating mirror 209 is provided with a thread 2011, which cooperates with the external thread of the lengthened arm 102, and the lengthened arm 102 and the rotating mirror 209 can also adopt other fixing modes. The rotating mirror 209 is internally provided with a lens groove 2010, and a convex lens 204 is installed in the lens groove 2010. The light source emitted by the laser is more collimated through the convex lens 204 inside the rotating mirror, improving the measurement accuracy of the measurement arm.

[0051] As Figure 6 shown, the outer wall of the first circuit board 201 is provided with a reinforcing hole 208, and a screw 203 is installed in the reinforcing hole 208, which fixes the first circuit board 201 and the left measurement arm 101 through the screw 203. The screw 203 and the reinforcing hole 208 are provided with four groups, and the four groups of screw 203 and reinforcing hole 208 are symmetrically distributed on the outer wall of the first circuit board 201. The four groups of screws 203 are fixed to ensure that the first circuit board does not move.

[0052] Combined with Figure 7 shown, the telescopic arm 106 is internally provided with a clamping groove 207, and a second circuit board 205 is installed in the clamping groove 207, one end of the second circuit board 205 is provided with a four-quadrant detector 206, the four-quadrant detector 206 belongs to the product of First Sensor company, model OP50-6, the other end of the second circuit board 205 is welded with a second signal line 9, and the telescopic arm 106 is internally provided with a second wire outlet hole 1014 for passing through the second signal line 9. As Figure 9 shown, the four-quadrant photoelectric detector is a photoelectric detector device arranged according to the requirements of rectangular coordinates by four photoelectric diodes (A, B, C, D) with the same performance, which can convert the light energy of laser into current output, and the second signal line 9 can output the voltage signal for processing, and also can supply power for the second circuit board 205.

[0053] The other end of the telescopic arm 106 is inserted into the right measuring arm 108. A fixing nut 109 is installed on the outer wall of the right measuring arm 108 to fix the telescopic arm 106. Four sets of fine-tuning nuts 107 are movably installed on the outer wall of the telescopic arm 106, with one end of each set distributed around the second circuit board 205. The fixing nut 109 controls the length of the telescopic arm 106, ensuring a suitable distance between the light source emitted by the laser 202 and the second circuit board 205. The four sets of fine-tuning nuts 107 control the position of the second circuit board 205, allowing the laser to more accurately strike the center of the photoelectric sensor on the second circuit board 205.

[0054] like Figure 10 The laser LD shown has three pins: an anode, a cathode (both of which are used to emit light), and a pin connected to a photodetector (PD) inside the LD.

[0055] like Figure 11 As shown, the working principle of this invention is as follows: The deformation of a solid shaft under thrust and torque is measured using laser self-mixing interferometry, and the thrust and torque are calculated from the deformation. The laser drive module drives the laser to emit laser light, which is then projected onto a four-quadrant detector through a lens. The signal from the four-quadrant detector is amplified and sent to a signal processing device for processing. The interference signal current output from the laser's PD pin is also sent to the signal processing device for further processing.

[0056] This invention features an installation mechanism that secures the left retaining ring 2 and the right retaining ring 8 to the surface of the solid shaft 1 using retaining ring nuts 4. Since the solid shaft 1 is cylindrical, the left retaining ring 2 and the right retaining ring 8 employ a semi-circular steel ring design to ensure stability and prevent loosening during rotation of the solid shaft 1. Four measuring arms are then evenly installed inside the left and right retaining rings, solving the installation problem. They are then fixed using mounting holes and baffle holes, ensuring that the four sets of measuring arms 10 are accurately and securely mounted on the solid shaft 1. The design of four sets of measuring arms also guarantees measurement accuracy, allowing the machine to continue operating even if one set is damaged. The measuring arm 10 adopts a left and right measuring arm design, which is bonded by a light shield 105. The light shield 105 can extend and retract freely, ensuring that the measuring arm 10 can be freely installed and removed. After installation and fixing, a pre-adjustment is performed by adjusting the fine-tuning nut 107 to ensure that the beam emitted by the laser 202 can hit the center position of the four-quadrant detector in a static state. At the same time, the fixing nut 109 can adjust the length of the telescopic arm 106 to adjust the distance between the laser and the four-quadrant detector.

[0057] The first circuit board is installed in the left measuring arm 101, mainly for power supply of the semiconductor laser and output of the current signal generated by interference; the second circuit board is installed in the right measuring arm 108, which is not only used for power supply of the four-quadrant photoconductive detector, but also can analyze the situation of the light spot on the photoelectric detector. Moreover, the thrust is detected by using the laser self-mixing interference, and the torque is directly measured by the four-quadrant detector, so that the thrust and the torque are separated for measurement, and the interference between them is reduced. Since the deformation of the solid shaft 1 caused by the thrust and the torque is very small, the laser self-interference technology can achieve the accuracy of 1 / 2 wavelength, and the deformation of 317 nm can be detected in the range of 317 nm, which can far meet the actual requirements of the thrust and torque measurement.

[0058] The rotating mirror 209 is arranged at the right end of the left measuring arm 101, and the rotating mirror is installed at the right end of the left measuring arm 101 through a rotating thread, which is not only convenient for installation, but also has a convex lens clamped in the rotating mirror 209, so that the light beam emitted by the laser is more collimated and hits the four-quadrant detector. The left measuring arm and the right measuring arm are connected through the light shielding sleeve made of black rubber, which can be freely stretched and contracted, so that the left and right measuring arms can be accurately installed in the left and right clamping rings; meanwhile, the laser self-interference is used to measure the displacement, which is very precise and sensitive to the light signal, and the setting of the light shielding sleeve ensures the normal measurement of the system and improves the measurement accuracy. The telescopic arm 106 is adopted in the right measuring arm 108, so that the distance between the light source and the four-quadrant photoelectric detector can be freely adjusted, and the position of the second circuit board can be freely adjusted through the fine adjustment nut, so that the light beam emitted by the laser can be collimated and hit the center of the four-quadrant photoelectric detector in the case that the measuring arm is stationary, and the measurement accuracy is improved.

[0059] During measurement, the solid shaft 1 will be deformed under the thrust, and the left and right measuring arms installed on the solid shaft will have a relative displacement in the X direction, so that the laser emitted by the laser in the left measuring arm hits the four-quadrant photoelectric detector of the right measuring arm. Since the light beam will be reflected on the surface of the four-quadrant photoelectric detector and back to the laser cavity, interference will be generated with the light beam emitted by itself, and the interference signal current is output through the PD pin of the laser, and then amplified through the first circuit board, and finally input to the computer through the first signal line for operation and interpretation of the thrust received by the solid shaft. According to the experimental results, the deformation of the solid shaft caused by the thrust satisfies the Hook's law, F=KX, which is a linear relationship, and the resolution reaches 317 nm. When the left and right measuring arms generate a displacement of 1 / 2 wavelength 317 nm, the light beam moves half a wavelength on the optical axis, and the phase changes T, and the time domain signal appears an interference fringe. The relationship between the deformation displacement D and the number of interference fringes N and the wavelength can be expressed as:

[0060]

[0061] According to Hooke's law F = KX, the thrust T can be expressed as where K is a constant.

[0062] In the measurement, when the solid shaft 1 is affected by the torque, the solid shaft 1 will produce displacement in the Y direction. Since the deformation amount is very small, it is about micron level movement, and the deformation of the solid shaft by the torque is considered to be linear. Therefore, the laser emitted by the laser in the left measuring arm hits the four-quadrant photodetector in the right measuring arm, and the four quadrants of the four-quadrant photodetector output different currents. By calculating the current of each quadrant, the displacement of the light spot on the four-quadrant detector can be calculated. Finally, the second signal line outputs it to the computer for processing to calculate the size of the torque.

[0063] Specifically, the four quadrants (A, B, C, D) of the four-quadrant photodetector output different currents. Since the four-quadrant detector outputs a current signal, when the laser hits the four-quadrant detector, the four-quadrant detector converts the light intensity on each quadrant (A, B, C, D) into a current output. Finally, the collected voltage signal converts the current output of each quadrant into a voltage:

[0064] V A = IR A V B = IR B V C = IR C V D = IR D R

[0065] where V A represents the voltage signal output by the A quadrant of the four-quadrant detector, I A represents the current signal output by the A quadrant of the four-quadrant detector; V B represents the voltage signal output by the B quadrant of the four-quadrant detector, I B represents the current signal output by the B quadrant of the four-quadrant detector; V C represents the voltage signal output by the C quadrant of the four-quadrant detector, I C represents the current signal output by the C quadrant of the four-quadrant detector; V D represents the voltage signal output by the D quadrant of the four-quadrant detector, I D represents the current signal output by the D quadrant of the four-quadrant detector; R represents the resistance of the four-quadrant detector.

[0066] The amplification circuit converts current into voltage, because the current value is small, set amplification 10000 times, so that the deformation of the shaft produces 900um, there is 1v voltage signal change. The signal processing device is to add and subtract the signals output by each quadrant.

[0067] When the solid shaft is affected by torque, X and Y direction displacement is generated, the deformation of the solid shaft belongs to linear relationship, the laser emitted by the laser in the left measuring arm hits the four-quadrant photodetector in the right measuring arm, the four quadrants of the four-quadrant photodetector will output different currents, the size of the torque is calculated by tracking the track of the center of the light spot, the current output by each quadrant of the four-quadrant detector is converted into voltage, X represents the voltage difference between the top two quadrants and the bottom two quadrants, Y represents the voltage difference between the left two quadrants and the right two quadrants,

[0068] X=(V A +V D )-(V B +V C )

[0069] Y=(V A +V B )-(V C +V D )

[0070] According to the displacement change of the light spot on the four quadrants, the displacement change of the light spot center in X and Y directions is (Δx, Δy), since the deformation of the solid shaft caused by the torque has X and Y axis changes, according to Hooke's law, the torque displacement L of the solid shaft within the material rigidity range is:

[0071]

[0072] Where ΔX and ΔY are the displacements of the light spot center in X and Y axes, the torque M calculated according to the torque of the bearing is:

[0073]

[0074] Where G is the shear modulus, I P is the moment of inertia, and ΔL is the distance between the clamps, all of which are constants, so the torque coefficient K M is a constant.

[0075] The four measuring arms are installed on the same shaft, and the strain should not differ much, and the final torque data will be calculated by adding and averaging the four groups, which will be more accurate.

[0076] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it is not intended to exclude myriad other embodiments of the present application that other inventors can develop based on the same general inventive concepts embodied by the described embodiments. That is, although the present application is described in terms of particular embodiments and illustrative figures, it should be apparent that the scope of the present application is not limited to these specific embodiments.

[0077] While the embodiments of the application have been shown and described herein, it is to be understood that the scope of the application, jointly pointed out in the appended claims, is not to be limited to the above-described embodiments but can be otherwise variously changed, modified, replaced, and altered within the principles and spirit of the present application.

Claims

1. A method for measuring the thrust and torque of a solid shaft, comprising using a device for measuring the thrust and torque of a solid shaft, characterized in that: The device for measuring the thrust and torque of a solid shaft includes a left and a right retaining ring movably mounted on the surface of the solid shaft. Four sets of measuring arms are evenly arranged on the same circumference between the left and right retaining rings. Each set of measuring arms includes a left measuring arm and a right measuring arm. A laser and a rotating mirror are installed inside the left measuring arm. The right measuring arm is equipped with a telescopic arm, and a four-quadrant photodetector is installed on the telescopic arm, so that the distance between the laser and the four-quadrant photodetector can be freely adjusted. The thrust of the solid shaft is measured using laser self-mixing interferometry, and the torque of the solid shaft is measured by the four-quadrant photodetector. The measurement method includes: measuring the deformation of the solid shaft under thrust using laser self-mixing interferometry, and finally calculating the thrust from the deformation; when the solid shaft is affected by torque, it produces displacements in the X and Y directions. The torque and the deformation of the solid shaft are linearly related. The laser emitted by the laser in the left measuring arm strikes a four-quadrant photodetector in the right measuring arm. The four quadrants of the four-quadrant photodetector output different currents. The magnitude of the torque is calculated by tracking the trajectory of the light spot center. The current output by each quadrant of the four-quadrant photodetector is converted into voltage. X represents the voltage difference between the top two quadrants and the bottom two quadrants, and Y represents the voltage difference between the left two quadrants and the right two quadrants. Based on the displacement changes of the light spot in the four quadrants, the displacement changes of the light spot center in the X and Y directions are respectively... , Since the deformation of the solid shaft caused by torque includes changes in both the X and Y axes, according to Hooke's Law, the torsional displacement L experienced by the solid shaft within the material's rigidity range is: ； in , These represent the displacements of the light spot center along the X and Y axes, respectively. The torque M, calculated based on the torsional displacement acting on the solid shaft, is: ； Where G is the shear modulus, For moment of inertia, Given the circlip spacing, and all three factors being constants, the torque coefficient K... M It is a constant.

2. The method for measuring the thrust and torque of a solid shaft according to claim 1, characterized in that: The left and right retaining rings are the same size, shape and material, each consisting of two sets of semi-circular steel rings. The upper and lower ends of the steel rings are provided with fixing plates, and adjacent fixing plates are fixedly connected by retaining ring nuts.

3. The method for measuring the thrust and torque of a solid shaft according to claim 1, characterized in that: Both the left and right retaining rings are provided with mounting holes for mounting the measuring arm and wiring holes. The mounting holes are used to fix the measuring arm in place, and the wiring holes are used to connect the signal line. One end of the left measuring arm and one end of the right measuring arm are respectively provided with a baffle, and the outer wall of the baffle is provided with baffle holes corresponding to the mounting holes.

4. The method for measuring the thrust and torque of a solid shaft according to claim 1, characterized in that: The left measuring arm is welded with an extension arm, and a first circuit board is installed inside the extension arm. The first circuit board is equipped with a laser. The other end of the extension arm is equipped with a threaded rotating mirror. The inner wall of the rotating mirror is threaded, and a lens groove is provided inside the rotating mirror. A convex lens is installed in the lens groove.

5. The method for measuring the thrust and torque of a solid shaft according to claim 4, characterized in that: The first circuit board has reinforcement holes on its outer wall, and screws are installed inside the reinforcement holes. The screws fix the first circuit board to the left measuring arm. There are four sets of screws and reinforcement holes, which are symmetrically distributed on the outer wall of the first circuit board.

6. The method for measuring the thrust and torque of a solid shaft according to claim 1, characterized in that: The right measuring arm is equipped with a telescopic arm, and the telescopic arm has a slot inside. A second circuit board is installed inside the slot, and a four-quadrant photodetector is installed on the second circuit board.

7. The method for measuring the thrust and torque of a solid shaft according to claim 1, characterized in that: A light-shielding sleeve is connected between the left and right measuring arms. The light-shielding sleeve is made of black rubber and can extend and retract freely.

8. The method for measuring the thrust and torque of a solid shaft according to claim 6, characterized in that: A fixing nut is installed on the outer wall of the right measuring arm. The length of the telescopic arm in the right measuring arm is controlled by the fixing nut. A fine-tuning nut is movably installed on the outer wall of the telescopic arm. There are four sets of fine-tuning nuts, which are used to control the position of the second circuit board so that the laser beam can be more accurately hit the center position of the four-quadrant photodetector on the second circuit board.

9. The method for measuring the thrust and torque of a solid shaft according to claim 4, characterized in that: The solid shaft deforms under the thrust, causing relative displacement in the X direction between the left and right measuring arms mounted on it. A laser beam emitted from the laser in the left measuring arm strikes a four-quadrant photodetector in the right measuring arm. The beam is reflected back into the laser cavity from the photodetector's surface, interfering with the laser beam it emitted earlier. An interference signal current is output through the laser's PD pin, amplified by the first circuit board inside the extended arm, and finally output through the first signal line for calculation. The thrust on the solid shaft is then calculated. The thrust and the deformation of the solid shaft satisfy Hooke's Law. The relationship between the deformation displacement D, the number of interference fringes N, and the wavelength λ is expressed as: ； Thrust T is expressed as , where K is a constant.

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